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Ridge Preservation Techniques in the Anterior Esthetic Zone Luis Brandam, DDS,* Hans Malmstrom, DDS,† Fawad Javed, BDS, PhD,* Jose-Luis Calvo-Guirado, DDS, MS, PhD,‡ and Georgios E. Romanos, DDS, PhD, Dr. Med. Dent§
he healing process in extraction ridges is characterized by internal changes that lead to bone formation within the ridge and external changes that result in loss of the alveolar ridge width and height. This loss of alveolar bone volume after tooth extraction often complicates prosthetic reconstruction after implant placement. To preserve the ridge contours, various techniques and grafting materials have been reported in the literature, with promising results. Several terms have been used to describe such attempts at conserving the integrity of the ridge walls after tooth extraction, including ridge preservation (RP) and site preservation. The authors consider the term ridge preservation to be the most precise and hence have used it in this review. Although many animal studies and clinical case series have demonstrated a role for alveolar ridge-preservation techniques, published reports have covered a wide gamut of techniques, including such variables as the extraction site location (anterior/posterior;
T
*Resident, Division of General Dentistry, Eastman Institute for Oral Health, University of Rochester, Rochester, NY. †Professor and Chair, Division of General Dentistry, Eastman Institute for Oral Health, University of Rochester, Rochester, NY. ‡Professor, Department of International Dentistry Research, Faculty of Medicine and Dentistry, San Antonio Catholic University of Murcia (UCAM), Murcia, Spain. §Professor, Department of Periodontology, School of Dental Medicine, Stony Brook University, Stony Brook, NY; Professor, Department of Oral Surgery and Implant Dentistry, University of Frankfurt, Dental School (Carolinum), Frankfurt, Germany.
Reprint requests and correspondence to: Georgios E. Romanos, DDS, PhD, Dr. Med. Dent., School of Dental Medicine, Stony Brook University, 106 Rockland Hall, Stony Brook, NY 11794-8700, Phone: (631) 632-8755, Fax: (631) 632-8670, E-mail: georgios.romanos@ stonybrook.edu ISSN 1056-6163/15/02406-699 Implant Dentistry Volume 24 Number 6 Copyright © 2015 Wolters Kluwer Health, Inc. All rights reserved. DOI: 10.1097/ID.0000000000000341
Purpose: Various techniques have been developed to limit resorption of the alveolar ridge after tooth extraction, and results from using them have been promising. The aim of this study was to evaluate the role and reliability of ridge preservation (RP) in the anterior esthetic zone, in anticipation of later implant placement. Materials and Methods: Using the MEDLINE and PubMed databases, searches were performed using combinations of different terms. Results: A total of 223 studies were identified, from which 55 articles were further examined. Of these, 11 studies were randomized clinical trials, controlled clinical trials, or prospective/retrospective studies with a minimum of 5 subjects
and at least 3 months of follow-up. Only human studies of RP for singlerooted tooth or bicuspid sites were included. Selection criteria also excluded studies in which primary closure was obtained. Conclusion: Although a direct comparison of the 11 articles was difficult because of the different techniques, materials, and healing time, no single graft material seemed to be superior. However, all studies found less ridge contraction at grafted than nongrafted sites. Longterm data about the outcomes for implants placed in sites where RP was attempted are still needed. (Implant Dent 2015;24:699–712) Key Words: anterior zone, bone graft, bone loss prevention, ridge preservation
maxillary/mandibular); whether a flap was elevated; whether grafting materials were used, and if so, what kind; whether a membrane was used; and whether primary closure of the ridge was obtained. The aim of this article was to focus on the anterior maxilla, asking whether using ridge-preservation techniques in the esthetic zone reliably preserves the alveolar ridge in preparation for dental implant placement?
extraction, implants-ridge preservation, ridge preservation, ridge-ridge, ridge alteration-extraction, ridge preservation-extraction ridge, and ridge preservation. The search was limited to human subjects. Bibliographies of reviews from 1994 to March 2012 were assessed for appropriate studies. Reference lists of studies identified were searched for further citations. Of those that were initially identified, studies were considered for inclusion in the present review if they were randomized clinical trials (RCTs), controlled clinical trials, or prospective/ retrospective studies with a minimum of 5 patients and a follow-up of at least
MATERIALS
AND
METHODS
In MEDLINE and PubMed, searches were performed for articles in English language using the following terms and combination of them: dentistry, implants, dental implants,
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RIDGE PRESERVATION TECHNIQUES
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ET AL
Table 1. Excluded Articles and Reason for Exclusion Article
Author
Year
Reason for Exclusion
Osseoretention? Comparative assessment of particulate hydroxyapatite inserted beneath immediate dentures A comparison of demineralized freeze-dried bone and autologous bone to induce bone formation in human extraction ridges Clinical and histological observations of sites implanted with intraoral autogenous bone grafts and allografts. Fifteen human case reports Bone regeneration in extraction sites after immediate placement of an e-PTFE membrane with or without a biomaterial Alveolar ridge preservation following extraction of maxillary teeth. Report on 23 consecutive cases A bone regenerative approach to alveolar ridge maintenance following tooth extraction. Report of 10 cases Preservation of alveolar bone in extraction ridges using bioabsorbable membranes Alveolar ridge reconstruction and/or preservation using root form bioglass cones Autogenous masticatory mucosal grafts in extraction ridge seal procedures: a comparison between ridges grafted with demineralized freeze-dried bone and deproteinized bovine bone mineral Histomorphometric evaluation of extraction ridges and deficient alveolar ridges treated with allograft and barrier membrane: a pilot study Histologic evaluation of human extraction ridges treated with DFDBA and cell occlusive membrane Preserving alveolar ridge anatomy following tooth removal in conjunction with immediate implant placement Changes in alveolar bone height and width following ridge augmentation using bone graft and membranes Porous bovine mineral in healing of human extraction ridges. Part 1: histomorphometric evaluations at 9 mo Evaluation of the effect of immediate grafting of mandibular postextraction ridges with synthetic bone Histological comparison of healing extraction ridges implanted with bioactive glass or demineralized-dried bone allograft: a pilot study Dental implant placed in extraction sites implanted with bioactive glass: Human histology and clinical outcome Use of HTR synthetic bone grafts in conjunction with immediate dental implants
Hoad-Reddick et al1 Becker et al2
1994
Primary closure
1994
Becker et al3
1996
Primary closure and periodontal teeth Unclear data and posterior teeth
Dies et al4
1996
Primary closure
Nemcovsky and Serfaty5 Lekovic et al6
1996
Primary closure by rotated flap Primary closure
Lekovic et al7
1998
Yilmaz et al8
1998
Tal9
1999
Primary closure (soft tissue from palate)
Smukler et al10
1999
Primary closure
Brugnami et al11
1999
Primary closure
Sclar12
1999
Lack of data
Simon et al13
2000
Artzi et al14
2000
Primary closure and augmented sites Primary closure
Bolouri et al15
2001
Primary closure
Froum et al16
2002
Primary closure
Norton and Wilson17 Yukna et al18
2002
Changes in alveolar bone height and width following postextraction ridge augmentation using a fixed bioabsorbable membrane and demineralized freeze-dried bone osteoinductive graft Bone healing and soft tissue contour changes following singletooth extraction: a clinical and radiographic 12-mo prospective study The use of bovine porous bone mineral in combination with collagen membrane or autologous fibrinogen/fibronectin system for ridge preservation following tooth extraction Healing of human extraction ridges filled with Bio-Oss
Zubillaga et al19
2003
Defected ridges and augmented sites Posterior teeth, primary closure and implants and graft at the same time Primary closure
Schropp et al20
2003
Posterior teeth
Vasilic et al21
2003
Primary closure
Carmagnola et al22
2003
Posterior teeth
1997
2003
Primary closure and periodontal teeth Primary closure
(continued on next page)
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Table 1. (Continued) Article
Author
Preservation of ridge dimensions following grafting with coral granules of 48 post-traumatic and post-extraction dentoalveolar defects Efficacy of bovine bone mineral for alveolar augmentation: a human histologic study Histologic evaluation of human biopsies after dental augmentation with demineralized bone matrix putty Comparison of an allograft in an experimental putty carrier and a bovine-derived xenograft used in ridge preservation: a clinical and histologic study in humans Extraction ridges and implantation of hydroxyapatite with membrane barriers: a histologic study Medical grade calcium sulphate hemihydrate in healing of human extraction ridges: clinical and histological observations at 3 mo Randomized study evaluating recombinant human bone morphogenetic protein-2 for extraction ridge augmentation Acellular dermal matrix and hydroxyapatite in prevention of ridge deformities after tooth extraction Titanium membranes in prevention of alveolar collapse after tooth extraction Immediate bone augmentation after infected tooth extraction using titanium membranes Xenograft versus extraction alone for ridge preservation after tooth removal: a clinical and histomorphometric study Preservation of the postextraction alveolar ridge: a clinical and histologic study Bone formation following implantation of bone biomaterials into extraction sites Magnesium-enriched hydroxyapatite compared with calcium sulfate in the healing of human extraction ridges: radiographic and histomorphometric evaluation at 3 mo Ridge bone maintenance in human after extraction Ridge preservation following tooth extraction: a comparison between atraumatic extraction and ridge seal surgery Buccal plate augmentation: a new alternative to ridge preservation Corticocancellous porcine bone in the healing of human extraction ridges: combining histomorphomerty with osteoblast gene expression profiles in vivo Ridge preservation using a composite bone graft and a bioabsorbable membrane with and without primary wound closure: a comparative clinical trial Analysis of tissue neogenesis in extraction ridges treated with GBR: clinical, histologic, and micro-CT results Histologic comparison of healing after ridge preservation using human demineralized bone matrix putty with one versus 2 different-sized bone particles
3 months after tooth extraction. Whenever a series of articles reported the same study, the article that included the clinical measurements and/or details about implant placement was selected. Only included were studies of RP for single-rooted teeth or bicuspids
Year
Reason for Exclusion
23
2003
Primary closure and bony defects on the ridge
Norton et al24
2003
Babbush et al25
2003
Vance et al26
2004
Primary closure and augmented sites Primary closure and augmented sites Primary closure
Froum et al27
2004
Primary closure
Guarnieri et al28
2004
Primary closure
Fiorellini et al29
2005
Luczyszyn et al30
2005
Pinho et al31
2006
Primary closure and no buccal wall Full-thickness flap elevation and periodontal teeth Primary closure
Kfir et al32
2007
Primary closure
Barone et al33
2008
Primary closure
Cardaropoli and Cardaropoli34 Molly et al35
2008
Posterior teeth
2008
Primary closure
Crespi et al36
2009
Primary closure (soft tissue graft) and no buccal wall
Casado et al37 Oghli and Steveling38 Caiazzo et al39
2010 2010
Crespi et al40
2011
Primary closure Primary closure (soft tissue graft) and no buccal wall 2 case reports, no measurements Molar teeth extractions
Engler-Hamm et al41
2011
Posterior teeth and primary closure in one group
Neiva et al42
2012
Primary closure
Hoang and Mealey43
2012
Primary closure
Sandor et al
for which primary closure was not obtained. Animal studies were thus excluded because they do not include single-root teeth, and the healing phase in animals is different from that in humans. Full-thickness flap was included to evaluate the thickness
2010
of the bone and bone architecture (Table 1). From each included study, the following data were obtained: number of patients and treated sites, position of sites, augmentation methods for test and control sites, observation period,
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Table 2. Characteristics of the Included Studies Study
Method CCT 16-wk follow-up
Participants
No
16 patients
Anterior or premolar
d
12 patients. Premolars and anterior teeth only
11 maxillary premolars, 6 maxillary incisors, 1 maxillary canine, 6 mandibular premolars
Yes
Upper and lower premolars, upper incisors, upper canines
d
2 upper premolars, 2 upper laterals and 1 upper central
d
24 patients. Maxillary premolars
Maxillary premolars
No
20 patients. Monoradicular tooth
Upper and lower premolars, incisors, and canines
d
Anterior maxilla
No
Iasella et al46
Serino et al47
2 study groups Parallel 4–6 mo of follow-up CT 2 study groups
45 patients
Wang and Tsao48
6-mo follow-up CCT
Periodontal status: periodontitis 5 patients
5–6 mo of follow-up No control group RCT 2 study groups Parallel 4-mo follow-up CT 2 study groups
Neiva et al49
Serino et al50
Aimetti et al51
Mardas et al52
3-mo follow-up RCT 2 study groups Parallel 3-mo follow-up RCT
Periodontal status: periodontitis 40 patients
2 study groups Parallel 8-mo follow-up CCT 6-mo follow-up No control group
Single root teeth or bicuspids
26 patients
40 patients Single root teeth
Maxillary or mandibular incisors, canine, or premolars
Yes but no heavy smokers (.10 cigarette per day)
24 sites in maxilla and 14 in mandible
Yes
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ET AL
(continued on next page)
BRANDAM
Beck and Mealey53
Smoking
Maxillary premolars and forward
No control group CCT Split-mouth design 6-mo follow-up RCT
Camargo et al45
Teeth
12 patients 6 RP of single root teeth and 6 bone augmentation
RIDGE PRESERVATION TECHNIQUES
Howell et al44
Study
Method 54
Wood and Mealey
RCT
Participants
Smoking No
11 maxillary incisors, 4 maxillary canines, 11 maxillary premolars, 6 mandibular premolars
ET AL
40 patients. Single root teeth (nonmolars)
Teeth
BRANDAM
Table 2. (Continued)
2 study groups Parallel 5-mo follow-up
Surgical Considerations
Intervention
Measurement Method
Outcome
2 teeth with periodontal bone loss. No active periodontitis
Full-thickness flap. Extraction, debrided, and decortication of the ridge with 1/2 bur. No primary closure
Test: application of the rhBMP2/ACS into the ridge
Periodontal probe, PA x-rays, and CT scan
Better than complete infill of the ridge
d
Flaps replaced in original position
Test: bioactive glass and Casulfate
Pins for fixed reference
Test with more internal ridge fill, less resorption in height, and similar resorption in width compared with controls
9.2 mm initial and after 4 mo 8.0 mm in RP; and 9.1 mm and 6.4 in extraction only
Control: clot d
Full-thickness mucoperiosteal flap
Control: extraction alone
Clinical + stent
Atraumatic extraction
Test: RP FDBA 500–1000 mm particle size, and a collagen membrane
Histologic analysis from biopsy
Test: bioabsorbable sponge of polylactide-polyglycolide acid, Fisiograft Control: natural healing Ridges filled with FDBA (Puros) and CollaPlug
Re-entry surgery at 6 mo + stent
No primary closure Teeth with bone loss
No primary closure
Yes
Atraumatic extraction. Ridge perforated with round bur. No primary closure
Biopsy taken Histologic analysis
Results showed less bone height resorption on the T sites (t sites +0.2 [1.5] and c sites −0.7 [1.2]) Vital bone 68.5% average, 3.8% graft particles and 27.7% CT/bone marrow
Biopsy was taken
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IMPLANT DENTISTRY / VOLUME 24, NUMBER 6 2015
Periodontal Status
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Table 2. (Continued) Periodontal Status
Yes, teeth with bone loss
Caries, root fracture, and residual roots
No periodontal disease
Measurement Method
Outcome
Test: putty P-15 and a bioabsorbable collagen wound dressing material
Clinical measurements and customized acrylic templates
No statistical significant between the ridge width in control and test sites; but there is a statistical significant in height
Control: bioabsorbable collagen wound dressing material only
Biopsy taken
Full-thickness flap elevation
Test: polylactide-polyglycolide acid, Fisiograft
Histological analysis
At the time of the implant placement, no particles of the grafted material were identified. No mention on the article about the vertical and horizontal changes of the ridge
No primary closure No primary closure
Control: natural healing Test: MGCSH
Re-entry at 3 mo and stent
Vertical resorption and reduction of the width were more pronounced at control sites than at MGCSH sites (1.2 versus 0.5 mm, and 3.2 versus 2.0 mm, respectively)
Control: no ridge filling
Biopsy was taken
Test: SBC
Biopsy was taken
Buccolingual width $ baseline 8 mm and 7 at 8 mo (SBC); baseline 9 mm and 6.9 at 8 mo (DBBM)
Group 1: 20 delayed healing group. Group 1: 20 early healing group
Periodontal probe and sharp calipers
No statistical significant difference between groups for any histologic parameter was identified
Implant placement within 3–6 wk after CT scan
Cone beam CT scan
Atraumatic extraction with degranulation
Full-thickness mucoperiosteal flap. Atraumatical extraction. Flaps were secured without primary closure
Intervention
RIDGE PRESERVATION TECHNIQUES
Yes
Surgical Considerations
Control: DBBM (Bio-Oss) In both groups a resorbable bilayer collagen barrier (BioGlide) was placed No periodontal disease
Atraumatic extraction. Graft non– freeze-dried cancellous mineralized human bone allograft (250–1000 mm). Bioabsorbable collagen wound dressing was placed on the top of the graft
BRANDAM
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ET AL
(continued on next page)
Periodontal Status
Intervention
Measurement Method
Atraumatic extraction
Group 1: DFDBA
Cone beam CT scan
No flap
Group 2: FDBA
Clinical measurements with calipers
No primary closure
Collagen membrane over either graft material Implant placed 18–20 wk after the RP No control group
Outcome No significant differences when comparing changes in the alveolar ridge dimensions of each group
ET AL
No less than 10 mm of bone
Surgical Considerations
BRANDAM
Table 2. (Continued)
PA, periapical.
Author Howell et al44 Camargo et al45 Iasella et al46 Serino et al47 Wang and Tsao48 Neiva et al49 Serino et al50 Aimetti et al51 Mardas et al52 Beck and Mealey53 Wood and Mealey54
Representative Population
Eligibly Criteria Defined
Randomization
Blinded
Reported Loss to Follow-up
No Yes Yes Yes No Yes Yes Yes Yes Yes
Yes Yes Yes Yes No Yes Yes Yes Yes Yes
d d d Yes No Yes Yes Yes Yes No
d d d Yes No Yes Yes Yes d d
No Yes Yes Yes No ? Yes Yes Yes Yes
Yes
Yes
Yes
No
Yes
No. of (%) Dropouts
Control Group
Risk of Bias
0 0 0 (20%) 0 ? (20%) 0 (13%) (17%)
No Yes Yes Yes No Yes Yes Yes Yes No
High High High Low High Moderate Low Moderate Moderate High
7 (17%)
No
Moderate
9
4 4 7
IMPLANT DENTISTRY / VOLUME 24, NUMBER 6 2015
Table 3. Characteristics of the Included Studies
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Table 4. Characteristics of the Included Studies Measurement
Followup, (mo)
Howell et al44
Periodontal probe, PA x-rays, and CT scan
4
Camargo et al45
Pins for fixed reference
6
Iasella et al46
Clinical + stent Histologic Analysis from biopsy Reentry surgery at 6 mo + stent
Serino et al47
Wang and Tsao48 Neiva et al49
Biopsy taken Histologic analysis
4–6
6
5–6
Intervention Test: rhBMP-2/ACS into the ridge d Test: bioactive glass and calcium sulfate Control: clot Test: FDBA Control: clot
d 7.86 (60.68)
d 4.38 (60.43)
d −0.38
d −3.48
d NSS
7.50 (60.74) 9.2 6 1.2 9.1 6 1.0
4.44 (60.27) 8.0 6 1.4 6.4 6 2.2
−1 1.3 6 2.0 −0.9 6 1.6
−3.06 −1.2 6 0.9 −2.6 6 2.3
NSS ,0.05 ,0.05
−0.7 6 1.2 ?
? ?
,0.01 ?
d Test: putty P-15
d ?
d ?
d 0.15 6 1.76
d −1.3 6 0.96
d NSS width, P , 0.05 height
?
?
−0.56 6 1.04
−1.43 6 1.05
?
?
?
?
NSS width, P , 0.05 height ?
? 9.4 6 2.2
? 7.4 6 2.0
? −0.5 6 1.1
? 2.0 6 1.1
? ,0.05
10.0 6 0.7 8.1 6 1
6.8 6 1.3 7 6 1.1
−1.2 6 0.6 −0.4 6 1
3.2 6 1.8 −1.1 6 1
Control: DBBM (Bio-Oss)
9 6 1.6
6.9 6 1.9
0.2 6 0.7
−2.1 6 1
Group 1: 20 delayed healing group Group 1: 20 early healing group Group 1: DFDBA
9.38 mean
?
0.37 6 1.46
1.47 6 1.81
8.47 mean
?
−0.32 6 2.61
1.43 6 1.89
NSS
9.70 6 1.13
?
−0.37 6 1.11
NSS
Group 2: FDBA
9.97 6 1.01
?
−0.57 6 1.18
−2.18 6 1.62 (−22.8%) −2.09 6 1.71 (−20.9%)
3
8
Control: clot Test: SBC
,0.05 ,0.05 width, NSS height ,0.05 width, NSS height NSS
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ET AL
NSS, not statistically significant; PA, periapical.
NSS
BRANDAM
Clinical measurements with calipers
?
? ?
Reentry at 3 mo and stent Biopsy was taken Biopsy was taken
5
?
? ?
Aimetti et al51
Cone beam CT scan
0.316 mm
,0.01
3
Wood and Mealey54
?
?
Histological analysis
3
P
?
0.2 6 1.5
Serino et al50
6
Change in Width (mm)
?
Control: bioabsorbable collagen wound dressing Test: polylactidepolyglycolide acid, Fisiograft Control: clot Test: MGCSH
Periodontal probe and sharp calipers Cone beam CT scan
Change in Height (mm)
?
4
Beck and Mealey53
End (mm)
Test: bioabsorbable sponge of polylactidepolyglycolide acid, Fisiograft Control: clot FDBA
Clinical measurements and customized acrylic templates Biopsy taken
Mardas et al52
Baseline (mm)
RIDGE PRESERVATION TECHNIQUES
Authors
IMPLANT DENTISTRY / VOLUME 24, NUMBER 6 2015
− ?
?
+ + ?
NSS NSS
NSS
? ? ?
1.43* −2.09*
−2.18*
? ? ? ? ,0.01 ? 0.316 0.9 ?
NSS −0.37*
RESULTS
4 6 3
NSS NSS −0.32* −0.57* 6 5
3
? ? ?
+ ?
+ + ? ? + NSS ,0.05 ,0.05 ,0.05 NSS 0.13 −1.2 −1.1* −2.1* 1.47* ,0.05 ,0.05 NSS NSS NSS 0.71 0.7 −0.4* 0.2* 0.37* 4 3 8
?
+ − ? ? +
+ ? ,0.05 ? 1.4 ? 4–6 5–6
2.2 ?
,0.05 ?
+ ?
+ NSS −0.42 6
0.62
NSS
−
Height
*No clot as a control group. Difference between baseline and final outcome. NSS, not statistically significant.
rhBMP-2/ACS polylactide-polyglycolide acid polylactide-polyglycolide acid Growth factor Sponge
DFDBA
Wood and Mealey54 Wood and Mealey54 Howell et al44 Serino et al47 Serino et al50 FDBA
Putty P-15 MGCSH SBC DBBM Mineralized human bone allograft
Iasella et al46 Wang and Tsao48 Neiva et al49 Aimetti et al51 Mardas et al52 Mardas et al52 Beck and Mealey53
Camargo et al
Bioactive glass and calcium sulphate FDBA FDBA Filler
707
and complications. The primary outcome evaluated was the change in ridge dimensions after tooth extraction and ridge-preservation therapy, measured as the change in the height and width of the alveolar process in millimeters or as a percentage. The secondary outcome was the success of the implant placement and the amount of grafting material found in the grafted site during the procedure.
45
Authors Intervention Method
Table 5. Evaluation of the Studies According to the Grafting Materials
Follow-up, (mo)
Difference in Height (mm) Between Test/Control
P
Difference in Width (mm) Between Test/Control
P
Width
ET AL
Summary
BRANDAM
A total of 223 studies initially were identified, from which 55 full-text articles were further examined. Of those, 11 studies met the inclusion criteria.44–54 These publications are briefly described in Table 2. Five studies were RCTs with 2 study groups and a follow-up period of between 3 and 8 months.46,49,51,52,54 Six studies were controlled clinical trials.44,45,47,48,50,53 Of these, 3 had a test and control group.45,47,50 Only 1 study used a split-mouth design,45 whereas the others all were parallel designs. All studies had a follow-up period of at least 3 months. The study populations ranged from 5 to 45 individuals. Smoking habits were described in 3 studies,46,52,53 whereas smokers were excluded from 4 studies.44,49,51,54 The other 4 studies did not mention the subjects’ smoking status.45,47,48,50 Full-thickness buccal and lingual flaps were elevated in most of the studies,44–50,52 whereas 3 studies attempted RP without opening a flap.51,53,54 In all the studies, the extraction ridges were carefully debrided before any graft material was inserted. None of the studies used primary closure. In all the studies in which full-thickness flaps were elevated, the tissue was sutured in its original position without advancing it to achieve primary closure. The reasons for extraction varied and included caries,44,51,53 periodontal bone loss,44,47,50 periodontal disease,48 nonrestorable roots,44,51 tooth fracture,48,51,53 and endodontic complications.48,52,53 Some studies did not specify the causes of tooth extraction.45,46,49,54 Atraumatic extraction was reported on different studies.45,46,48,49,51–54
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BRANDAM
? ? ? ? 27.7 ? ? ? ? ? ? ? ? 39.6 6 13.0 41.3 6 14.6 52.7 6 7.9 49.9 6 11.0
RIDGE PRESERVATION TECHNIQUES
% Connective Tissue
708
ET AL
Decortication with a bur was performed by 2 groups.44,48 The other researchers did only degranulation of the ridge but not decortication. Some authors44–46,51–54 prescribed antibiotics for at least 1 week after extraction(s) and RP.
65.2 6 6.4 62.6 6 7.4 ? ? 58.8 6 3.5 47.2 6 7.7 ? ? ? ? ? ?
26 6 11 34 6 12 ? ?
37 6 18 d 0 d 3.8 6.25 d 0 d 0 d ? ? 14.6 6 12.9 13.5 6 12.2 8.9 6 12.8 25.4 6 17.0 28 6 14 54 6 12 67 6 19 44 6 9 68.5 29.9 6 8.4 36.5 6 7.7 59.9 6 22.4 48.8 6 14.4 ? ? ? ? 45.8 6 22.4 45.0 6 19.8 38.4 6 14.5 24.6 6 13.6 MGCSH
SBC DBBM Mineralized human bone allograft
Aimetti et al51
Mardas et al52
DFDBA FDBA
Sponge Serino et al50
Wood and Mealey54
FDBA Putty P-15 Wang and Tsao48 Neiva et al49
FDBA Iasella et al
Beck and Mealey53
Sponge Serino et al47
Preservation Extraction alone Preservation Extraction alone Preservation Preservation Collagen dressing Preservation Extraction alone Preservation Extraction alone Preservation Preservation 3 mo preservation 6 mo preservation Preservation Preservation
% Graft Material Graft Material
46
Authors
Table 6. Histological Results of the Studies
Site
% Bone
% Trabecular Bone
Bone Grafting Materials
Graft material was used alone in some studies44,45,47,50,51 and in combination with a membrane in others.46,48,49,52–54 Filler materials were used in most of the studies.45,46,48,49,51–54 Sponges (bioabsorbable polylactide-polyglycolide acid) were used in 2,47,50 and a growth factor (rhBMP-2/ACS) was used only in 1 study44 (Table 3–5). Among the fillers, human bone allograft was used most commonly.46,48,53,54 This included freeze-dried bone allograft (FDBA),46,48,54 mineralized non–freezedried allograft,53 and demineralized freeze-dried bone allograft (DFDBA).48 One group52 used the xenograft demineralized bovine bone mineral (DBBM). Alloplasts used in the studies45,49,51,52 were bioactive glass, hydroxyapatite, and medical-grade calcium sulfate hemihydrate (MGCSH). Dimensional changes in the ridges were assessed by clinical, radiographic, or acrylic stent examination, or some combination of those. Three groups44,53,54 used computed tomographic scanning, whereas other means of assessment included intraoperative measurement of the width of the alveolar ridge at the time of re-entry,47,51 the use of acrylic stents,46,47,49–51 and the use of titanium pins on the outer surface of the buccal bone as a reference.45 Eight of the groups46–53 used histological analysis to identify new bone formation in the ridge. The quality of the studies was assessed by considering the following factors: whether the study population was representative, whether eligibility criteria were defined, whether treatment was randomized and blinded, whether loss to follow-up was reported (along with the percentage of drop-outs), and whether a control group was included. Based on these factors, the risk of bias for each study was determined, and 5 studies were considered to have a high risk of being biased.44–46,53 Four studies were considered to have a moderate
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IMPLANT DENTISTRY / VOLUME 24, NUMBER 6 2015
NA
Yes
Bone Dimension Outcomes
Yes
Yes 5 Yes
NA
3 and 6 Yes Yes
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risk,49,51,52,54 with only 2 studies considered to have a low risk (Table 2).47,50
34/38 good primary stability. 4/38 insufficient bone width Good primary stability in all of the implants. One subject did not have enough bone width for implant placement Yes
8 Yes
8/12 implants 4/38 implants
Yes
3 3 Yes Yes
9/13 implants
Yes Yes
6 5–6 4 Yes Yes Yes
NA NA
Yes Yes Yes
Table 3 displays the changes in the extraction-ridge height and/or, as reported in 9 of the studies. Two of the studies used only histological analysis and did not record the ridge dimensions. Those that compared the use of a ridgepreservation technique with natural healing45–47,50,51 showed that the height of the alveolus in the test groups was better preserved, that is, the average height of the alveolar process of the control group was significantly lower than that of the test group. Overall, the control groups showed a change in the alveolar height ranging between −1.2 and 0.2 mm, whereas the ridge-preservation group was more heterogeneous, demonstrating vertical bone loss that ranged between −0.57 and 1.3 mm. Differences between test and control groups were found to be statistically significant by the authors in 4 studies.46,47,49,51 Mardas et al52 found a statistically significant difference between the baseline and outcome values of both groups treated (with Straumann ceramic bone and DBBM). Three studies45,46,51 measured the change in the width in test group extraction ridges and control group extraction ridges that healed naturally. The reduction of the ridge width in the control groups ranged between 3.2 and −3.06 mm, whereas in the test groups it ranged between 2 and −3.48 mm.
SBC Mardas et al52
Wood and Mealey54
Sponge MGCSH Serino et al50 Aimetti et al51
DBBM Mineralized human bone allograft DFDBA
Sponge FDBA Putty P-15 Serino et al47 Wang and Tsao48 Neiva et al49
Beck and Mealey53
FDBA
Histological Outcomes
FDBA
Comments Histology
Yes
Some sites with dehiscence NA NA NA 4–6 Yes
Secondary Bone Augmentation Graft Material
Time After Extraction, (mo) Implant Placement Authors
Table 7. Final Clinical Outcome
Some sites with dehiscence requires secondary bone augmentation Good primary stability in all of the implants d One implant has not had primary stability in the control group Good primary stability in all C and T groups No radiographically difference between the bone in C and T groups Bone resistance during trephination was similar for both groups. One patient in DBBM group had no primary stability, and the implant placement was not possible
ET AL
Iasella et al46
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Nine of 11 studies examined the histology of biopsies from the graft sites. Four studies46,47,50,51 analyzed the test and control ridges histomorphometrically and showed similar results, with approximately 50% new bone formation (Table 6). Among the 3 studies that used FDBA as a graft material,46,48,54 the results reported by Iasella et al46 and Wood and Mealey54 were similar (% bone: 28 6 14/24.6 6 13.6 and % graft material: 37 6 18/25.4 6 17.0, respectively), but they differed from those reported by Wang et al48 (% bone: 68.5 and % graft material: 3.8). Wood and Mealey54 also analyzed results from using DFDBA and found
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a higher percentage of bone and a lower percentage of graft particles in that group than the FDBA group. Three studies47,50,51 found no remaining graft material at the time of the biopsy, after using a bioabsorbable sponge of polylactide-polyglycolide acid as a graft material47,50 and calcium sulfate.51 Neiva et al49 found a lower percentage of bone in the group augmented with P-15 putty (29.9 6 8.4) than in the control group, which had received only a collagen dressing (36.5 6 7.7). Implant-Related Outcomes
The objective of RP is to make it possible to later place implants with ideal diameters in the ideal positions. Although the studies included in this review reported placing implants at various times after extraction in sites grafted with a variety of materials, none of them reported the size of the implants or whether they were placed in the ideal position. Nine of the 11 studies reported on implant placement (Table 7). The other 2 studies did not, nor did they analyze the histology of the preserved site. None of the studies specified whether implants were placed in the test or control group, but many implants were satisfactorily placed in both groups.47,50,51 Primary implant stability was achieved in almost all of the implants. Some subjects did not have enough width after the RP, and implants could not be placed without secondary bone augmentation.46,52–54
DISCUSSION To create implant-supported dental prostheses that function ideally and have excellent esthetics, the implants must be in the correct 3-dimensional position. Sufficient alveolar bone volume and a favorable ridge architecture are essential to achieving this. Otherwise, an inappropriate restoration-implant alignment may result, complicating restorative treatment. The aim of extraction-RP is to maintain the vertical and horizontal bone and the integrity of the soft tissue to enable later placement of implants that are optimally dimensioned and
positioned. It is well known that the alveolar ridge tends to resorb after tooth extraction. This resorption typically affects the buccal wall, with the alveolar crest shifting lingually.55 Given this and the fact that the majority of anterior maxillary buccal walls have a width of 0.5 to 1 mm,55,56 any postextraction collapse of the alveolar bone width and height can be expected to significantly affect future implant placement. A question that arises is whether RP is indicated if there are sufficient bone walls and no infection is present. Can placing an implant immediately in the fresh extraction ridge limit the resorption? A number of previous studies have addressed this question.55–58 However, these studies do not demonstrate that immediate implant placement predictably controls either buccal wall resorption or soft-tissue recession, and thus esthetic outcomes are unpredictable. Among the techniques proposed for RP is primary closure of the ridge. Bone loss is a well-recognized consequence of flap elevation.55 It is known that after a flap procedure, there is evidently bone loss, and this bone loss depends on the alveolar ridge architecture. Patients with thin buccal bone are particularly likely to experience significant bone loss, because of the high osteoclastic activity.55 When RP was evaluated in 2011 with and without primary closure,55 the researchers concluded that the width of ridges treated without primary closure decreased by 24%, compared with 28% in the primary closure group. Moreover, the RP without primary closure better preserved the keratinized mucosa and resulted in less postoperative patient discomfort. The concept of RP to maintain the ridge for future implant must be differentiated from guided bone regeneration (GBR), in which a grafting material and a barrier membrane are placed and primary closure is achieved.55 In general, GBR is indicated if an augmentation or corrective surgery of a defect for a future implant placement is planned. RP is indicated if the ridge is intact, and the objective to preserve as much tissue as possible in preparation for future implant placement. No fenestrations,
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dehiscences, sinus communication, periodontal pockets, or apical pathology should be present. The literature suggests that some confusion between RP and the GBR technique exists. Therefore, the authors propose a new definition of “ridge preservation”: a procedure in which grafting material is placed in the intact alveolus after atraumatic tooth extraction, without flap elevation, to preserve the alveolar ridge, with the final objective of an implant placement in the ideal position. A related question is the ideal time for implant placement after the RP. Although researchers have found extractions ridges to be substantially filled at 40 days55 and completely filled at 10 weeks,55 when biopsies from grafted ridges were compared at 3 and 6 months,53 no statistically significant difference in the percentage of bone and graft material present was found. The authors believe that 3 months is a reliable healing time for achieving good primary stability of the implant and subsequent osseointegration. Future studies are planned to answer this question. The literature is conspicuously silent regarding the outcomes of implant rehabilitation after RP. Implants have been placed in sites where RP was undertaken and in control sites, but there is a lack of information about the tridimensional positioning of those implants, as well as how deeply or shallowly the placement was, relative to adjacent teeth. Similarly, the role of implant design, important especially in the anterior esthetic zone, is unexamined.
CONCLUSION The studies reviewed used different preservation techniques, grafting materials, and healing times, but all of them found less vertical and horizontal ridge contraction at grafted extraction sites than at nongrafted ones. Depending on the graft material and technique, some degree of residual graft was found, as well as new bone formation. The use of membranes seemed to optimize final outcomes. Three months seems to be a sufficient healing time after RP to enable new bone formation that will
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allow for placement of implants with good primary stability. The studies reviewed did not provide evidence of superiority of one graft material over another. Furthermore, they provided no data regarding the impact of RP on esthetic outcomes or long-term implant outcomes. Such data are still needed.
DISCLOSURE The authors claim to have no financial interest, either directly or indirectly, in the products or information listed in the article.
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35. Molly L, Vandromme H, Quirynen M, et al. Bone formation following implantation of bone biomaterials into extraction sites. J Periodontol. 2008;79:1108–1115. 36. Crespi R, Capparè P, Gherlone E. Magnesium-enriched hydroxyapatite compared to calcium sulfate in the healing of human extraction ridges: Radiographic and histomorphometric evaluation at 3 months. J Periodontol. 2009;80:210–218. 37. Casado PL, Duarte ME, Carvalho W, et al. Ridge bone maintenance in human after extraction. Implant Dent. 2010;19:314–322. 38. Oghli AA, Steveling H. Ridge preservation following tooth extraction: A comparison between atraumatic extraction and ridge seal surgery. Quintessence Int. 2010; 41:605–609. 39. Caiazzo A, Brugnami F, Mehra P. Buccal plate augmentation: A new alternative to ridge preservation. J Oral Maxillofac Surg. 2010;68:2503–2506. 40. Crespi R, Capparé P, Romanos GE, et al. Corticocancellous porcine bone in the healing of human extraction ridges: Combining histomorphometry with osteoblast gene expression profiles in vivo. Int J Oral Maxillofac Implants. 2011;26:866–872. 41. Engler-Hamm D, Cheung W, Yen A, et al. Ridge preservation using a composite bone graft and a bioabsorbable membrane with and without primary wound closure: A comparative clinical trial. J Periodontol. 2011;82:377–387. 42. Neiva R, Pagni G, Duarte F, et al. Analysis of tissue neogenesis in extraction ridges treated with guided bone regeneration: Clinical, histologic, and micro-CT results. Int J Periodontics Rest Dent. 2011; 31:457–469. 43. Hoang TN, Mealey BL. Histologic comparison of healing after ridge preser-
vation using human demineralized bone matrix putty with one versus two different-sized bone particles. J Periodontol. 2012;83:174–181. 44. Howell H, Jones A, Nummikoski P, et al. A feasibility study evaluating rhBMP2/absorbable collagen sponge device for local alveolar ridge preservation or augmentation. Int J Periodontics Rest Dent. 1997;17:124–139. 45. Camargo P, Lekovic P, Weinlaender M, et al. Influence of bioactive glass on changes in alveolar process dimensions after exodontia. Oral Surg Oral Med Oral Pathol Oral Radiol Endos. 2000;90: 581–586. 46. Iasella J, Greenwell H, Miller RL, et al. Ridge preservation with freeze-dried bone allograft and a collagen membrane compared to extraction alone for implant site development: A clinical and histologic study in humans. J Periodontol. 2003;74: 990–999. 47. Serino G, Biancu S, Iezzi G, et al. Ridge preservation following tooth extraction using a polylactide and polyglycolide sponge as spacer filler: A clinical and histological study in human. Clin Oral Implants Res. 2003;14:651–658. 48. Wang HL, Tsao YP. Histologic evaluation of ridge augmentation with mineralized human allograft. Int J Periodontics Rest Dent. 2008;28:231–237. 49. Neiva R, Tsao YP, Eber R, et al. Effects of a putty-form hydroxyapatite matrix combined with the synthetic cellbinding peptide P-15 on alveolar ridge preservation. J Periodontol. 2008;79: 291–299. 50. Serino G, Rao W, Iezzi G, et al. Polylactide and polyglycolide sponge used in human extraction ridges: Bone formation
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following 3 months after its application. Clin Oral Implants Res. 2008;19:26–31. 51. Aimetti M, Romano F, Griga FB, et al. Clinical and histologic healing of human extraction ridges filled with calcium sulfate. Int J Oral Maxillofac Implants. 2009;24:902–909. 52. Mardas N, Chadha V, Donos N. Alveolar ridge preservation with guided bone regeneration and a synthetic bone substitute or a bovine-derived xenograft: A randomized, controlled clinical trial. Clin Oral Implants Res. 2010;21:688–698. 53. Beck T, Mealey B. Histologic analysis of healing after tooth extraction with ridge preservation using mineralized human bone allograft. J Periodontol. 2010;81:1765–1772. 54. Wood R, Mealey B. Histological comparison of healing following tooth extraction with ridge preservation using mineralized vs. demineralized freeze-dried bone allograft. J Periodontol. 2012;83:329–336. 55. Covani U, Ricci M, Bozzolo G, et al. Analysis of the pattern of the alveolar ridge remodeling following single tooth extraction. Clin Oral Implants Res. 2011; 22:820–825. 56. Huynh-Ba G, Pjetursson B, Sanz M, et al. Analysis of the ridge bone wall dimensions in the upper maxilla in relation to immediate implant placement. Clin Oral Implants Res. 2010;21:37–42. 57. Januario AL, Duarte WR, Barriviera M, et al. Dimension of the facial bone wall in the anterior maxilla: A cone-beam computed tomography study. Clin Oral Implants Res. 2011;22:1168–1171. 58. Botticelli D, Berglundh T, Lindhe J. Hard-tissue alterations following immediate implant placement in extraction sites. J Clin Periodont. 2004;31:820–828.
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Ridge Preservation Techniques in the Anterior Esthetic Zone Luis Brandam, DDS,* Hans Malmstrom, DDS,† Fawad Javed, BDS, PhD,* Jose-Luis Calvo-Guirado, DDS, MS, PhD,‡ and Georgios E. Romanos, DDS, PhD, Dr. Med. Dent§
he healing process in extraction ridges is characterized by internal changes that lead to bone formation within the ridge and external changes that result in loss of the alveolar ridge width and height. This loss of alveolar bone volume after tooth extraction often complicates prosthetic reconstruction after implant placement. To preserve the ridge contours, various techniques and grafting materials have been reported in the literature, with promising results. Several terms have been used to describe such attempts at conserving the integrity of the ridge walls after tooth extraction, including ridge preservation (RP) and site preservation. The authors consider the term ridge preservation to be the most precise and hence have used it in this review. Although many animal studies and clinical case series have demonstrated a role for alveolar ridge-preservation techniques, published reports have covered a wide gamut of techniques, including such variables as the extraction site location (anterior/posterior;
T
*Resident, Division of General Dentistry, Eastman Institute for Oral Health, University of Rochester, Rochester, NY. †Professor and Chair, Division of General Dentistry, Eastman Institute for Oral Health, University of Rochester, Rochester, NY. ‡Professor, Department of International Dentistry Research, Faculty of Medicine and Dentistry, San Antonio Catholic University of Murcia (UCAM), Murcia, Spain. §Professor, Department of Periodontology, School of Dental Medicine, Stony Brook University, Stony Brook, NY; Professor, Department of Oral Surgery and Implant Dentistry, University of Frankfurt, Dental School (Carolinum), Frankfurt, Germany.
Reprint requests and correspondence to: Georgios E. Romanos, DDS, PhD, Dr. Med. Dent., School of Dental Medicine, Stony Brook University, 106 Rockland Hall, Stony Brook, NY 11794-8700, Phone: (631) 632-8755, Fax: (631) 632-8670, E-mail: georgios.romanos@ stonybrook.edu ISSN 1056-6163/15/02406-699 Implant Dentistry Volume 24 Number 6 Copyright © 2015 Wolters Kluwer Health, Inc. All rights reserved. DOI: 10.1097/ID.0000000000000341
Purpose: Various techniques have been developed to limit resorption of the alveolar ridge after tooth extraction, and results from using them have been promising. The aim of this study was to evaluate the role and reliability of ridge preservation (RP) in the anterior esthetic zone, in anticipation of later implant placement. Materials and Methods: Using the MEDLINE and PubMed databases, searches were performed using combinations of different terms. Results: A total of 223 studies were identified, from which 55 articles were further examined. Of these, 11 studies were randomized clinical trials, controlled clinical trials, or prospective/retrospective studies with a minimum of 5 subjects
and at least 3 months of follow-up. Only human studies of RP for singlerooted tooth or bicuspid sites were included. Selection criteria also excluded studies in which primary closure was obtained. Conclusion: Although a direct comparison of the 11 articles was difficult because of the different techniques, materials, and healing time, no single graft material seemed to be superior. However, all studies found less ridge contraction at grafted than nongrafted sites. Longterm data about the outcomes for implants placed in sites where RP was attempted are still needed. (Implant Dent 2015;24:699–712) Key Words: anterior zone, bone graft, bone loss prevention, ridge preservation
maxillary/mandibular); whether a flap was elevated; whether grafting materials were used, and if so, what kind; whether a membrane was used; and whether primary closure of the ridge was obtained. The aim of this article was to focus on the anterior maxilla, asking whether using ridge-preservation techniques in the esthetic zone reliably preserves the alveolar ridge in preparation for dental implant placement?
extraction, implants-ridge preservation, ridge preservation, ridge-ridge, ridge alteration-extraction, ridge preservation-extraction ridge, and ridge preservation. The search was limited to human subjects. Bibliographies of reviews from 1994 to March 2012 were assessed for appropriate studies. Reference lists of studies identified were searched for further citations. Of those that were initially identified, studies were considered for inclusion in the present review if they were randomized clinical trials (RCTs), controlled clinical trials, or prospective/ retrospective studies with a minimum of 5 patients and a follow-up of at least
MATERIALS
AND
METHODS
In MEDLINE and PubMed, searches were performed for articles in English language using the following terms and combination of them: dentistry, implants, dental implants,
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Table 1. Excluded Articles and Reason for Exclusion Article
Author
Year
Reason for Exclusion
Osseoretention? Comparative assessment of particulate hydroxyapatite inserted beneath immediate dentures A comparison of demineralized freeze-dried bone and autologous bone to induce bone formation in human extraction ridges Clinical and histological observations of sites implanted with intraoral autogenous bone grafts and allografts. Fifteen human case reports Bone regeneration in extraction sites after immediate placement of an e-PTFE membrane with or without a biomaterial Alveolar ridge preservation following extraction of maxillary teeth. Report on 23 consecutive cases A bone regenerative approach to alveolar ridge maintenance following tooth extraction. Report of 10 cases Preservation of alveolar bone in extraction ridges using bioabsorbable membranes Alveolar ridge reconstruction and/or preservation using root form bioglass cones Autogenous masticatory mucosal grafts in extraction ridge seal procedures: a comparison between ridges grafted with demineralized freeze-dried bone and deproteinized bovine bone mineral Histomorphometric evaluation of extraction ridges and deficient alveolar ridges treated with allograft and barrier membrane: a pilot study Histologic evaluation of human extraction ridges treated with DFDBA and cell occlusive membrane Preserving alveolar ridge anatomy following tooth removal in conjunction with immediate implant placement Changes in alveolar bone height and width following ridge augmentation using bone graft and membranes Porous bovine mineral in healing of human extraction ridges. Part 1: histomorphometric evaluations at 9 mo Evaluation of the effect of immediate grafting of mandibular postextraction ridges with synthetic bone Histological comparison of healing extraction ridges implanted with bioactive glass or demineralized-dried bone allograft: a pilot study Dental implant placed in extraction sites implanted with bioactive glass: Human histology and clinical outcome Use of HTR synthetic bone grafts in conjunction with immediate dental implants
Hoad-Reddick et al1 Becker et al2
1994
Primary closure
1994
Becker et al3
1996
Primary closure and periodontal teeth Unclear data and posterior teeth
Dies et al4
1996
Primary closure
Nemcovsky and Serfaty5 Lekovic et al6
1996
Primary closure by rotated flap Primary closure
Lekovic et al7
1998
Yilmaz et al8
1998
Tal9
1999
Primary closure (soft tissue from palate)
Smukler et al10
1999
Primary closure
Brugnami et al11
1999
Primary closure
Sclar12
1999
Lack of data
Simon et al13
2000
Artzi et al14
2000
Primary closure and augmented sites Primary closure
Bolouri et al15
2001
Primary closure
Froum et al16
2002
Primary closure
Norton and Wilson17 Yukna et al18
2002
Changes in alveolar bone height and width following postextraction ridge augmentation using a fixed bioabsorbable membrane and demineralized freeze-dried bone osteoinductive graft Bone healing and soft tissue contour changes following singletooth extraction: a clinical and radiographic 12-mo prospective study The use of bovine porous bone mineral in combination with collagen membrane or autologous fibrinogen/fibronectin system for ridge preservation following tooth extraction Healing of human extraction ridges filled with Bio-Oss
Zubillaga et al19
2003
Defected ridges and augmented sites Posterior teeth, primary closure and implants and graft at the same time Primary closure
Schropp et al20
2003
Posterior teeth
Vasilic et al21
2003
Primary closure
Carmagnola et al22
2003
Posterior teeth
1997
2003
Primary closure and periodontal teeth Primary closure
(continued on next page)
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Table 1. (Continued) Article
Author
Preservation of ridge dimensions following grafting with coral granules of 48 post-traumatic and post-extraction dentoalveolar defects Efficacy of bovine bone mineral for alveolar augmentation: a human histologic study Histologic evaluation of human biopsies after dental augmentation with demineralized bone matrix putty Comparison of an allograft in an experimental putty carrier and a bovine-derived xenograft used in ridge preservation: a clinical and histologic study in humans Extraction ridges and implantation of hydroxyapatite with membrane barriers: a histologic study Medical grade calcium sulphate hemihydrate in healing of human extraction ridges: clinical and histological observations at 3 mo Randomized study evaluating recombinant human bone morphogenetic protein-2 for extraction ridge augmentation Acellular dermal matrix and hydroxyapatite in prevention of ridge deformities after tooth extraction Titanium membranes in prevention of alveolar collapse after tooth extraction Immediate bone augmentation after infected tooth extraction using titanium membranes Xenograft versus extraction alone for ridge preservation after tooth removal: a clinical and histomorphometric study Preservation of the postextraction alveolar ridge: a clinical and histologic study Bone formation following implantation of bone biomaterials into extraction sites Magnesium-enriched hydroxyapatite compared with calcium sulfate in the healing of human extraction ridges: radiographic and histomorphometric evaluation at 3 mo Ridge bone maintenance in human after extraction Ridge preservation following tooth extraction: a comparison between atraumatic extraction and ridge seal surgery Buccal plate augmentation: a new alternative to ridge preservation Corticocancellous porcine bone in the healing of human extraction ridges: combining histomorphomerty with osteoblast gene expression profiles in vivo Ridge preservation using a composite bone graft and a bioabsorbable membrane with and without primary wound closure: a comparative clinical trial Analysis of tissue neogenesis in extraction ridges treated with GBR: clinical, histologic, and micro-CT results Histologic comparison of healing after ridge preservation using human demineralized bone matrix putty with one versus 2 different-sized bone particles
3 months after tooth extraction. Whenever a series of articles reported the same study, the article that included the clinical measurements and/or details about implant placement was selected. Only included were studies of RP for single-rooted teeth or bicuspids
Year
Reason for Exclusion
23
2003
Primary closure and bony defects on the ridge
Norton et al24
2003
Babbush et al25
2003
Vance et al26
2004
Primary closure and augmented sites Primary closure and augmented sites Primary closure
Froum et al27
2004
Primary closure
Guarnieri et al28
2004
Primary closure
Fiorellini et al29
2005
Luczyszyn et al30
2005
Pinho et al31
2006
Primary closure and no buccal wall Full-thickness flap elevation and periodontal teeth Primary closure
Kfir et al32
2007
Primary closure
Barone et al33
2008
Primary closure
Cardaropoli and Cardaropoli34 Molly et al35
2008
Posterior teeth
2008
Primary closure
Crespi et al36
2009
Primary closure (soft tissue graft) and no buccal wall
Casado et al37 Oghli and Steveling38 Caiazzo et al39
2010 2010
Crespi et al40
2011
Primary closure Primary closure (soft tissue graft) and no buccal wall 2 case reports, no measurements Molar teeth extractions
Engler-Hamm et al41
2011
Posterior teeth and primary closure in one group
Neiva et al42
2012
Primary closure
Hoang and Mealey43
2012
Primary closure
Sandor et al
for which primary closure was not obtained. Animal studies were thus excluded because they do not include single-root teeth, and the healing phase in animals is different from that in humans. Full-thickness flap was included to evaluate the thickness
2010
of the bone and bone architecture (Table 1). From each included study, the following data were obtained: number of patients and treated sites, position of sites, augmentation methods for test and control sites, observation period,
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702
Table 2. Characteristics of the Included Studies Study
Method CCT 16-wk follow-up
Participants
No
16 patients
Anterior or premolar
d
12 patients. Premolars and anterior teeth only
11 maxillary premolars, 6 maxillary incisors, 1 maxillary canine, 6 mandibular premolars
Yes
Upper and lower premolars, upper incisors, upper canines
d
2 upper premolars, 2 upper laterals and 1 upper central
d
24 patients. Maxillary premolars
Maxillary premolars
No
20 patients. Monoradicular tooth
Upper and lower premolars, incisors, and canines
d
Anterior maxilla
No
Iasella et al46
Serino et al47
2 study groups Parallel 4–6 mo of follow-up CT 2 study groups
45 patients
Wang and Tsao48
6-mo follow-up CCT
Periodontal status: periodontitis 5 patients
5–6 mo of follow-up No control group RCT 2 study groups Parallel 4-mo follow-up CT 2 study groups
Neiva et al49
Serino et al50
Aimetti et al51
Mardas et al52
3-mo follow-up RCT 2 study groups Parallel 3-mo follow-up RCT
Periodontal status: periodontitis 40 patients
2 study groups Parallel 8-mo follow-up CCT 6-mo follow-up No control group
Single root teeth or bicuspids
26 patients
40 patients Single root teeth
Maxillary or mandibular incisors, canine, or premolars
Yes but no heavy smokers (.10 cigarette per day)
24 sites in maxilla and 14 in mandible
Yes
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ET AL
(continued on next page)
BRANDAM
Beck and Mealey53
Smoking
Maxillary premolars and forward
No control group CCT Split-mouth design 6-mo follow-up RCT
Camargo et al45
Teeth
12 patients 6 RP of single root teeth and 6 bone augmentation
RIDGE PRESERVATION TECHNIQUES
Howell et al44
Study
Method 54
Wood and Mealey
RCT
Participants
Smoking No
11 maxillary incisors, 4 maxillary canines, 11 maxillary premolars, 6 mandibular premolars
ET AL
40 patients. Single root teeth (nonmolars)
Teeth
BRANDAM
Table 2. (Continued)
2 study groups Parallel 5-mo follow-up
Surgical Considerations
Intervention
Measurement Method
Outcome
2 teeth with periodontal bone loss. No active periodontitis
Full-thickness flap. Extraction, debrided, and decortication of the ridge with 1/2 bur. No primary closure
Test: application of the rhBMP2/ACS into the ridge
Periodontal probe, PA x-rays, and CT scan
Better than complete infill of the ridge
d
Flaps replaced in original position
Test: bioactive glass and Casulfate
Pins for fixed reference
Test with more internal ridge fill, less resorption in height, and similar resorption in width compared with controls
9.2 mm initial and after 4 mo 8.0 mm in RP; and 9.1 mm and 6.4 in extraction only
Control: clot d
Full-thickness mucoperiosteal flap
Control: extraction alone
Clinical + stent
Atraumatic extraction
Test: RP FDBA 500–1000 mm particle size, and a collagen membrane
Histologic analysis from biopsy
Test: bioabsorbable sponge of polylactide-polyglycolide acid, Fisiograft Control: natural healing Ridges filled with FDBA (Puros) and CollaPlug
Re-entry surgery at 6 mo + stent
No primary closure Teeth with bone loss
No primary closure
Yes
Atraumatic extraction. Ridge perforated with round bur. No primary closure
Biopsy taken Histologic analysis
Results showed less bone height resorption on the T sites (t sites +0.2 [1.5] and c sites −0.7 [1.2]) Vital bone 68.5% average, 3.8% graft particles and 27.7% CT/bone marrow
Biopsy was taken
(continued on next page)
IMPLANT DENTISTRY / VOLUME 24, NUMBER 6 2015
Periodontal Status
703
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704
Table 2. (Continued) Periodontal Status
Yes, teeth with bone loss
Caries, root fracture, and residual roots
No periodontal disease
Measurement Method
Outcome
Test: putty P-15 and a bioabsorbable collagen wound dressing material
Clinical measurements and customized acrylic templates
No statistical significant between the ridge width in control and test sites; but there is a statistical significant in height
Control: bioabsorbable collagen wound dressing material only
Biopsy taken
Full-thickness flap elevation
Test: polylactide-polyglycolide acid, Fisiograft
Histological analysis
At the time of the implant placement, no particles of the grafted material were identified. No mention on the article about the vertical and horizontal changes of the ridge
No primary closure No primary closure
Control: natural healing Test: MGCSH
Re-entry at 3 mo and stent
Vertical resorption and reduction of the width were more pronounced at control sites than at MGCSH sites (1.2 versus 0.5 mm, and 3.2 versus 2.0 mm, respectively)
Control: no ridge filling
Biopsy was taken
Test: SBC
Biopsy was taken
Buccolingual width $ baseline 8 mm and 7 at 8 mo (SBC); baseline 9 mm and 6.9 at 8 mo (DBBM)
Group 1: 20 delayed healing group. Group 1: 20 early healing group
Periodontal probe and sharp calipers
No statistical significant difference between groups for any histologic parameter was identified
Implant placement within 3–6 wk after CT scan
Cone beam CT scan
Atraumatic extraction with degranulation
Full-thickness mucoperiosteal flap. Atraumatical extraction. Flaps were secured without primary closure
Intervention
RIDGE PRESERVATION TECHNIQUES
Yes
Surgical Considerations
Control: DBBM (Bio-Oss) In both groups a resorbable bilayer collagen barrier (BioGlide) was placed No periodontal disease
Atraumatic extraction. Graft non– freeze-dried cancellous mineralized human bone allograft (250–1000 mm). Bioabsorbable collagen wound dressing was placed on the top of the graft
BRANDAM
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ET AL
(continued on next page)
Periodontal Status
Intervention
Measurement Method
Atraumatic extraction
Group 1: DFDBA
Cone beam CT scan
No flap
Group 2: FDBA
Clinical measurements with calipers
No primary closure
Collagen membrane over either graft material Implant placed 18–20 wk after the RP No control group
Outcome No significant differences when comparing changes in the alveolar ridge dimensions of each group
ET AL
No less than 10 mm of bone
Surgical Considerations
BRANDAM
Table 2. (Continued)
PA, periapical.
Author Howell et al44 Camargo et al45 Iasella et al46 Serino et al47 Wang and Tsao48 Neiva et al49 Serino et al50 Aimetti et al51 Mardas et al52 Beck and Mealey53 Wood and Mealey54
Representative Population
Eligibly Criteria Defined
Randomization
Blinded
Reported Loss to Follow-up
No Yes Yes Yes No Yes Yes Yes Yes Yes
Yes Yes Yes Yes No Yes Yes Yes Yes Yes
d d d Yes No Yes Yes Yes Yes No
d d d Yes No Yes Yes Yes d d
No Yes Yes Yes No ? Yes Yes Yes Yes
Yes
Yes
Yes
No
Yes
No. of (%) Dropouts
Control Group
Risk of Bias
0 0 0 (20%) 0 ? (20%) 0 (13%) (17%)
No Yes Yes Yes No Yes Yes Yes Yes No
High High High Low High Moderate Low Moderate Moderate High
7 (17%)
No
Moderate
9
4 4 7
IMPLANT DENTISTRY / VOLUME 24, NUMBER 6 2015
Table 3. Characteristics of the Included Studies
705
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706
Table 4. Characteristics of the Included Studies Measurement
Followup, (mo)
Howell et al44
Periodontal probe, PA x-rays, and CT scan
4
Camargo et al45
Pins for fixed reference
6
Iasella et al46
Clinical + stent Histologic Analysis from biopsy Reentry surgery at 6 mo + stent
Serino et al47
Wang and Tsao48 Neiva et al49
Biopsy taken Histologic analysis
4–6
6
5–6
Intervention Test: rhBMP-2/ACS into the ridge d Test: bioactive glass and calcium sulfate Control: clot Test: FDBA Control: clot
d 7.86 (60.68)
d 4.38 (60.43)
d −0.38
d −3.48
d NSS
7.50 (60.74) 9.2 6 1.2 9.1 6 1.0
4.44 (60.27) 8.0 6 1.4 6.4 6 2.2
−1 1.3 6 2.0 −0.9 6 1.6
−3.06 −1.2 6 0.9 −2.6 6 2.3
NSS ,0.05 ,0.05
−0.7 6 1.2 ?
? ?
,0.01 ?
d Test: putty P-15
d ?
d ?
d 0.15 6 1.76
d −1.3 6 0.96
d NSS width, P , 0.05 height
?
?
−0.56 6 1.04
−1.43 6 1.05
?
?
?
?
NSS width, P , 0.05 height ?
? 9.4 6 2.2
? 7.4 6 2.0
? −0.5 6 1.1
? 2.0 6 1.1
? ,0.05
10.0 6 0.7 8.1 6 1
6.8 6 1.3 7 6 1.1
−1.2 6 0.6 −0.4 6 1
3.2 6 1.8 −1.1 6 1
Control: DBBM (Bio-Oss)
9 6 1.6
6.9 6 1.9
0.2 6 0.7
−2.1 6 1
Group 1: 20 delayed healing group Group 1: 20 early healing group Group 1: DFDBA
9.38 mean
?
0.37 6 1.46
1.47 6 1.81
8.47 mean
?
−0.32 6 2.61
1.43 6 1.89
NSS
9.70 6 1.13
?
−0.37 6 1.11
NSS
Group 2: FDBA
9.97 6 1.01
?
−0.57 6 1.18
−2.18 6 1.62 (−22.8%) −2.09 6 1.71 (−20.9%)
3
8
Control: clot Test: SBC
,0.05 ,0.05 width, NSS height ,0.05 width, NSS height NSS
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ET AL
NSS, not statistically significant; PA, periapical.
NSS
BRANDAM
Clinical measurements with calipers
?
? ?
Reentry at 3 mo and stent Biopsy was taken Biopsy was taken
5
?
? ?
Aimetti et al51
Cone beam CT scan
0.316 mm
,0.01
3
Wood and Mealey54
?
?
Histological analysis
3
P
?
0.2 6 1.5
Serino et al50
6
Change in Width (mm)
?
Control: bioabsorbable collagen wound dressing Test: polylactidepolyglycolide acid, Fisiograft Control: clot Test: MGCSH
Periodontal probe and sharp calipers Cone beam CT scan
Change in Height (mm)
?
4
Beck and Mealey53
End (mm)
Test: bioabsorbable sponge of polylactidepolyglycolide acid, Fisiograft Control: clot FDBA
Clinical measurements and customized acrylic templates Biopsy taken
Mardas et al52
Baseline (mm)
RIDGE PRESERVATION TECHNIQUES
Authors
IMPLANT DENTISTRY / VOLUME 24, NUMBER 6 2015
− ?
?
+ + ?
NSS NSS
NSS
? ? ?
1.43* −2.09*
−2.18*
? ? ? ? ,0.01 ? 0.316 0.9 ?
NSS −0.37*
RESULTS
4 6 3
NSS NSS −0.32* −0.57* 6 5
3
? ? ?
+ ?
+ + ? ? + NSS ,0.05 ,0.05 ,0.05 NSS 0.13 −1.2 −1.1* −2.1* 1.47* ,0.05 ,0.05 NSS NSS NSS 0.71 0.7 −0.4* 0.2* 0.37* 4 3 8
?
+ − ? ? +
+ ? ,0.05 ? 1.4 ? 4–6 5–6
2.2 ?
,0.05 ?
+ ?
+ NSS −0.42 6
0.62
NSS
−
Height
*No clot as a control group. Difference between baseline and final outcome. NSS, not statistically significant.
rhBMP-2/ACS polylactide-polyglycolide acid polylactide-polyglycolide acid Growth factor Sponge
DFDBA
Wood and Mealey54 Wood and Mealey54 Howell et al44 Serino et al47 Serino et al50 FDBA
Putty P-15 MGCSH SBC DBBM Mineralized human bone allograft
Iasella et al46 Wang and Tsao48 Neiva et al49 Aimetti et al51 Mardas et al52 Mardas et al52 Beck and Mealey53
Camargo et al
Bioactive glass and calcium sulphate FDBA FDBA Filler
707
and complications. The primary outcome evaluated was the change in ridge dimensions after tooth extraction and ridge-preservation therapy, measured as the change in the height and width of the alveolar process in millimeters or as a percentage. The secondary outcome was the success of the implant placement and the amount of grafting material found in the grafted site during the procedure.
45
Authors Intervention Method
Table 5. Evaluation of the Studies According to the Grafting Materials
Follow-up, (mo)
Difference in Height (mm) Between Test/Control
P
Difference in Width (mm) Between Test/Control
P
Width
ET AL
Summary
BRANDAM
A total of 223 studies initially were identified, from which 55 full-text articles were further examined. Of those, 11 studies met the inclusion criteria.44–54 These publications are briefly described in Table 2. Five studies were RCTs with 2 study groups and a follow-up period of between 3 and 8 months.46,49,51,52,54 Six studies were controlled clinical trials.44,45,47,48,50,53 Of these, 3 had a test and control group.45,47,50 Only 1 study used a split-mouth design,45 whereas the others all were parallel designs. All studies had a follow-up period of at least 3 months. The study populations ranged from 5 to 45 individuals. Smoking habits were described in 3 studies,46,52,53 whereas smokers were excluded from 4 studies.44,49,51,54 The other 4 studies did not mention the subjects’ smoking status.45,47,48,50 Full-thickness buccal and lingual flaps were elevated in most of the studies,44–50,52 whereas 3 studies attempted RP without opening a flap.51,53,54 In all the studies, the extraction ridges were carefully debrided before any graft material was inserted. None of the studies used primary closure. In all the studies in which full-thickness flaps were elevated, the tissue was sutured in its original position without advancing it to achieve primary closure. The reasons for extraction varied and included caries,44,51,53 periodontal bone loss,44,47,50 periodontal disease,48 nonrestorable roots,44,51 tooth fracture,48,51,53 and endodontic complications.48,52,53 Some studies did not specify the causes of tooth extraction.45,46,49,54 Atraumatic extraction was reported on different studies.45,46,48,49,51–54
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BRANDAM
? ? ? ? 27.7 ? ? ? ? ? ? ? ? 39.6 6 13.0 41.3 6 14.6 52.7 6 7.9 49.9 6 11.0
RIDGE PRESERVATION TECHNIQUES
% Connective Tissue
708
ET AL
Decortication with a bur was performed by 2 groups.44,48 The other researchers did only degranulation of the ridge but not decortication. Some authors44–46,51–54 prescribed antibiotics for at least 1 week after extraction(s) and RP.
65.2 6 6.4 62.6 6 7.4 ? ? 58.8 6 3.5 47.2 6 7.7 ? ? ? ? ? ?
26 6 11 34 6 12 ? ?
37 6 18 d 0 d 3.8 6.25 d 0 d 0 d ? ? 14.6 6 12.9 13.5 6 12.2 8.9 6 12.8 25.4 6 17.0 28 6 14 54 6 12 67 6 19 44 6 9 68.5 29.9 6 8.4 36.5 6 7.7 59.9 6 22.4 48.8 6 14.4 ? ? ? ? 45.8 6 22.4 45.0 6 19.8 38.4 6 14.5 24.6 6 13.6 MGCSH
SBC DBBM Mineralized human bone allograft
Aimetti et al51
Mardas et al52
DFDBA FDBA
Sponge Serino et al50
Wood and Mealey54
FDBA Putty P-15 Wang and Tsao48 Neiva et al49
FDBA Iasella et al
Beck and Mealey53
Sponge Serino et al47
Preservation Extraction alone Preservation Extraction alone Preservation Preservation Collagen dressing Preservation Extraction alone Preservation Extraction alone Preservation Preservation 3 mo preservation 6 mo preservation Preservation Preservation
% Graft Material Graft Material
46
Authors
Table 6. Histological Results of the Studies
Site
% Bone
% Trabecular Bone
Bone Grafting Materials
Graft material was used alone in some studies44,45,47,50,51 and in combination with a membrane in others.46,48,49,52–54 Filler materials were used in most of the studies.45,46,48,49,51–54 Sponges (bioabsorbable polylactide-polyglycolide acid) were used in 2,47,50 and a growth factor (rhBMP-2/ACS) was used only in 1 study44 (Table 3–5). Among the fillers, human bone allograft was used most commonly.46,48,53,54 This included freeze-dried bone allograft (FDBA),46,48,54 mineralized non–freezedried allograft,53 and demineralized freeze-dried bone allograft (DFDBA).48 One group52 used the xenograft demineralized bovine bone mineral (DBBM). Alloplasts used in the studies45,49,51,52 were bioactive glass, hydroxyapatite, and medical-grade calcium sulfate hemihydrate (MGCSH). Dimensional changes in the ridges were assessed by clinical, radiographic, or acrylic stent examination, or some combination of those. Three groups44,53,54 used computed tomographic scanning, whereas other means of assessment included intraoperative measurement of the width of the alveolar ridge at the time of re-entry,47,51 the use of acrylic stents,46,47,49–51 and the use of titanium pins on the outer surface of the buccal bone as a reference.45 Eight of the groups46–53 used histological analysis to identify new bone formation in the ridge. The quality of the studies was assessed by considering the following factors: whether the study population was representative, whether eligibility criteria were defined, whether treatment was randomized and blinded, whether loss to follow-up was reported (along with the percentage of drop-outs), and whether a control group was included. Based on these factors, the risk of bias for each study was determined, and 5 studies were considered to have a high risk of being biased.44–46,53 Four studies were considered to have a moderate
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IMPLANT DENTISTRY / VOLUME 24, NUMBER 6 2015
NA
Yes
Bone Dimension Outcomes
Yes
Yes 5 Yes
NA
3 and 6 Yes Yes
709
risk,49,51,52,54 with only 2 studies considered to have a low risk (Table 2).47,50
34/38 good primary stability. 4/38 insufficient bone width Good primary stability in all of the implants. One subject did not have enough bone width for implant placement Yes
8 Yes
8/12 implants 4/38 implants
Yes
3 3 Yes Yes
9/13 implants
Yes Yes
6 5–6 4 Yes Yes Yes
NA NA
Yes Yes Yes
Table 3 displays the changes in the extraction-ridge height and/or, as reported in 9 of the studies. Two of the studies used only histological analysis and did not record the ridge dimensions. Those that compared the use of a ridgepreservation technique with natural healing45–47,50,51 showed that the height of the alveolus in the test groups was better preserved, that is, the average height of the alveolar process of the control group was significantly lower than that of the test group. Overall, the control groups showed a change in the alveolar height ranging between −1.2 and 0.2 mm, whereas the ridge-preservation group was more heterogeneous, demonstrating vertical bone loss that ranged between −0.57 and 1.3 mm. Differences between test and control groups were found to be statistically significant by the authors in 4 studies.46,47,49,51 Mardas et al52 found a statistically significant difference between the baseline and outcome values of both groups treated (with Straumann ceramic bone and DBBM). Three studies45,46,51 measured the change in the width in test group extraction ridges and control group extraction ridges that healed naturally. The reduction of the ridge width in the control groups ranged between 3.2 and −3.06 mm, whereas in the test groups it ranged between 2 and −3.48 mm.
SBC Mardas et al52
Wood and Mealey54
Sponge MGCSH Serino et al50 Aimetti et al51
DBBM Mineralized human bone allograft DFDBA
Sponge FDBA Putty P-15 Serino et al47 Wang and Tsao48 Neiva et al49
Beck and Mealey53
FDBA
Histological Outcomes
FDBA
Comments Histology
Yes
Some sites with dehiscence NA NA NA 4–6 Yes
Secondary Bone Augmentation Graft Material
Time After Extraction, (mo) Implant Placement Authors
Table 7. Final Clinical Outcome
Some sites with dehiscence requires secondary bone augmentation Good primary stability in all of the implants d One implant has not had primary stability in the control group Good primary stability in all C and T groups No radiographically difference between the bone in C and T groups Bone resistance during trephination was similar for both groups. One patient in DBBM group had no primary stability, and the implant placement was not possible
ET AL
Iasella et al46
BRANDAM
Nine of 11 studies examined the histology of biopsies from the graft sites. Four studies46,47,50,51 analyzed the test and control ridges histomorphometrically and showed similar results, with approximately 50% new bone formation (Table 6). Among the 3 studies that used FDBA as a graft material,46,48,54 the results reported by Iasella et al46 and Wood and Mealey54 were similar (% bone: 28 6 14/24.6 6 13.6 and % graft material: 37 6 18/25.4 6 17.0, respectively), but they differed from those reported by Wang et al48 (% bone: 68.5 and % graft material: 3.8). Wood and Mealey54 also analyzed results from using DFDBA and found
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710
RIDGE PRESERVATION TECHNIQUES
a higher percentage of bone and a lower percentage of graft particles in that group than the FDBA group. Three studies47,50,51 found no remaining graft material at the time of the biopsy, after using a bioabsorbable sponge of polylactide-polyglycolide acid as a graft material47,50 and calcium sulfate.51 Neiva et al49 found a lower percentage of bone in the group augmented with P-15 putty (29.9 6 8.4) than in the control group, which had received only a collagen dressing (36.5 6 7.7). Implant-Related Outcomes
The objective of RP is to make it possible to later place implants with ideal diameters in the ideal positions. Although the studies included in this review reported placing implants at various times after extraction in sites grafted with a variety of materials, none of them reported the size of the implants or whether they were placed in the ideal position. Nine of the 11 studies reported on implant placement (Table 7). The other 2 studies did not, nor did they analyze the histology of the preserved site. None of the studies specified whether implants were placed in the test or control group, but many implants were satisfactorily placed in both groups.47,50,51 Primary implant stability was achieved in almost all of the implants. Some subjects did not have enough width after the RP, and implants could not be placed without secondary bone augmentation.46,52–54
DISCUSSION To create implant-supported dental prostheses that function ideally and have excellent esthetics, the implants must be in the correct 3-dimensional position. Sufficient alveolar bone volume and a favorable ridge architecture are essential to achieving this. Otherwise, an inappropriate restoration-implant alignment may result, complicating restorative treatment. The aim of extraction-RP is to maintain the vertical and horizontal bone and the integrity of the soft tissue to enable later placement of implants that are optimally dimensioned and
positioned. It is well known that the alveolar ridge tends to resorb after tooth extraction. This resorption typically affects the buccal wall, with the alveolar crest shifting lingually.55 Given this and the fact that the majority of anterior maxillary buccal walls have a width of 0.5 to 1 mm,55,56 any postextraction collapse of the alveolar bone width and height can be expected to significantly affect future implant placement. A question that arises is whether RP is indicated if there are sufficient bone walls and no infection is present. Can placing an implant immediately in the fresh extraction ridge limit the resorption? A number of previous studies have addressed this question.55–58 However, these studies do not demonstrate that immediate implant placement predictably controls either buccal wall resorption or soft-tissue recession, and thus esthetic outcomes are unpredictable. Among the techniques proposed for RP is primary closure of the ridge. Bone loss is a well-recognized consequence of flap elevation.55 It is known that after a flap procedure, there is evidently bone loss, and this bone loss depends on the alveolar ridge architecture. Patients with thin buccal bone are particularly likely to experience significant bone loss, because of the high osteoclastic activity.55 When RP was evaluated in 2011 with and without primary closure,55 the researchers concluded that the width of ridges treated without primary closure decreased by 24%, compared with 28% in the primary closure group. Moreover, the RP without primary closure better preserved the keratinized mucosa and resulted in less postoperative patient discomfort. The concept of RP to maintain the ridge for future implant must be differentiated from guided bone regeneration (GBR), in which a grafting material and a barrier membrane are placed and primary closure is achieved.55 In general, GBR is indicated if an augmentation or corrective surgery of a defect for a future implant placement is planned. RP is indicated if the ridge is intact, and the objective to preserve as much tissue as possible in preparation for future implant placement. No fenestrations,
BRANDAM
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dehiscences, sinus communication, periodontal pockets, or apical pathology should be present. The literature suggests that some confusion between RP and the GBR technique exists. Therefore, the authors propose a new definition of “ridge preservation”: a procedure in which grafting material is placed in the intact alveolus after atraumatic tooth extraction, without flap elevation, to preserve the alveolar ridge, with the final objective of an implant placement in the ideal position. A related question is the ideal time for implant placement after the RP. Although researchers have found extractions ridges to be substantially filled at 40 days55 and completely filled at 10 weeks,55 when biopsies from grafted ridges were compared at 3 and 6 months,53 no statistically significant difference in the percentage of bone and graft material present was found. The authors believe that 3 months is a reliable healing time for achieving good primary stability of the implant and subsequent osseointegration. Future studies are planned to answer this question. The literature is conspicuously silent regarding the outcomes of implant rehabilitation after RP. Implants have been placed in sites where RP was undertaken and in control sites, but there is a lack of information about the tridimensional positioning of those implants, as well as how deeply or shallowly the placement was, relative to adjacent teeth. Similarly, the role of implant design, important especially in the anterior esthetic zone, is unexamined.
CONCLUSION The studies reviewed used different preservation techniques, grafting materials, and healing times, but all of them found less vertical and horizontal ridge contraction at grafted extraction sites than at nongrafted ones. Depending on the graft material and technique, some degree of residual graft was found, as well as new bone formation. The use of membranes seemed to optimize final outcomes. Three months seems to be a sufficient healing time after RP to enable new bone formation that will
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allow for placement of implants with good primary stability. The studies reviewed did not provide evidence of superiority of one graft material over another. Furthermore, they provided no data regarding the impact of RP on esthetic outcomes or long-term implant outcomes. Such data are still needed.
DISCLOSURE The authors claim to have no financial interest, either directly or indirectly, in the products or information listed in the article.
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