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Lateral Alveolar Ridge Augmentation Using Tenting Screws, Acellular Dermal Matrix, and Freeze-Dried Bone Allograft Alone or with Particulate Autogenous Bone Gregory R. Caldwell, DDS, MS1 Michael P. Mills, DMD, MS2 Richard Finlayson, DDS2 Brian L. Mealey, DDS, MS3
This randomized prospective study evaluated the clinical benefits of using a corticocancellous mixture of freeze-dried bone allograft alone or in combination (1:1) with particulated autogenous bone for horizontal ridge augmentation and subsequent implant placement. Twenty-four patients with atrophic ridges received lateral ridge augmentations with particulate grafts placed around tenting screws and covered with a fixed acellular dermal matrix membrane. Thirty-three standard-diameter implants were successfully placed in 21 patients after a 24-week graft healing period. Three patients experienced early postoperative infections following the grafting procedure (12.5% of sites). At reentry, the allograft alone group showed similar average horizontal ridge width gains (3.33 ± 0.83 mm) to the combination group (3.09 ± 0.63 mm; P = .44). The mean graft resorption between baseline and reentry averaged 13.89%. (Int J Periodontics Restorative Dent 2015;35:75–83. doi: 10.11607/prd.2260)
Private Practice, El Paso, Texas, USA. Clinical Associate Professor, Department of Periodontics, University of Texas Health Science Center San Antonio, San Antonio, Texas, USA. 3Professor and Graduate Program Director, Department of Periodontics, University of Texas Health Science Center at San Antonio, San Antonio, Texas, USA. 1 2
Correspondence to: Dr Gregory Caldwell, Caldwell & Dimmitt Periodontics, 9398 Viscount Bldg. 1-A, El Paso, TX 79925, USA; fax: 915-593-7478; email: [email protected]. ©2015 by Quintessence Publishing Co Inc.
The success of implant dentistry has been largely related to the advent of bone augmentation techniques that allow for the regeneration of atrophic alveolar ridges into an ideal ridge form and for placement of implants in their ideal functional and esthetic positions.1–4 The current practice for ridge augmentation consists of a variety of techniques, including particulate grafts, onlay block grafts, ridge splitting, distraction osteogenesis, or a combination of these techniques.2,5–7 Guided bone regeneration (GBR) studies utilizing both nonresorbable and resorbable membranes have shown great success with horizontal alveolar ridge augmentation.2,5–13 Resorbable membranes are typically made of polyesters or tissue-derived collagens from human and animal sources.2 Acelluar dermal matrix (AlloDerm, LifeCell) has been successfully used for root coverage, thickening of soft tissues, and GBR.14–17 AlloDerm GBR (BioHorizons) is a thinner version (thickness, 0.5 to 0.9 mm) of the original AlloDerm product (thickness, 0.9 to 1.6 mm), specifically designed for GBR.
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76 Aside from soft tissue exclusion and clot stability, space maintenance is key to the success of GBR and can be accomplished in various ways using titanium-reinforced nonresorbable membranes, titanium mesh, particulate grafts and/ or block grafts, dental implants, or tenting screws.2,7,8,10,18–20 Nonresorbable2,20–24 and resorbable tenting screws25 have been used to aid in space maintenance, decrease graft mobility, and relieve external pressure on the graft. Autogenous bone is still considered by many to be the gold standard graft material for GBR because of its osteogenic, osteoinductive, and osteoconductive properties.7,26 Autogenous bone is commonly harvested from the ramus and symphysis but has been associated with increased patient morbidity.2,27,28 As an alternative to autogenous grafts, various bone substitutes, including xenografts, alloplasts, and allografts are used as adjuncts for GBR with successful clinical and histologic outcomes.7,13,21 However, some have advocated mixing autogenous bone with the various bone substitutes in order to combine the osteogenic and osteoinductive growth factors of autogenous bone with the osteoconductive properties of a bone substitute.10,12,29,30 Others have advocated applying the combination graft using a bilayer or sandwich technique with the most osteogenic or osteoinductive grafting material placed against the native bone and covered by an osteoconductive graft for space maintenance.29,31
Only one nonrandomized human study has compared the clinical outcomes of GBR procedures in atrophic ridges using particulate freeze-dried bone allograft (FDBA) alone or in combination with particulate autogenous bone using a bilayer technique.29 This study found no statistical difference in horizontal and/or vertical bone formation between treatment groups but had several weaknesses, including a high spontaneous membrane exposure rate (24%), lack of randomization and standardization between treatment groups, and imprecise ridge width gain measurement techniques. The purpose of the present study was to further evaluate the clinical benefits, or lack thereof, of using an allograft alone or in combination (1:1) with particulated autogenous bone for horizontal ridge augmentation and subsequent implant placement.
Method and materials This was a nonmasked, randomized, prospective clinical trial. Twenty-seven systemically healthy partially edentulous patients who were referred to the University of Texas Health Science Center at San Antonio Graduate Periodontics Clinic for lateral ridge augmentation and dental implant placement were included in the study. Eleven periodontics residents under direct supervision of board-certified periodontics faculty completed the surgical procedures between April 2012 and January 2014. The
principal investigator (GRC) or coprincipal investigator (BLM) was present for all of the surgical procedures and made all of the intraoperative study measurements. Study sites were required to exhibit a partially edentulous ridge with inadequate buccolingual dimension for the placement of a standarddiameter dental implant, as measured clinically and radiographically using cone beam computed tomography (CBCT). Exclusion criteria included heavy smoking (>10 cigarettes per day), active periodontal disease, uncontrolled systemic diseases, infectious diseases, pregnancy, or a history of bone-altering medications that could interfere with the treatment. Following enrollment and written consent, patients were randomized into a treatment group by selecting from a group of sealed envelopes, each containing a piece of paper labeled either “Group 1: Autogenous + FDBA” or “Group 2: FDBA.” Study sites were classified based on arch (maxillary or mandibular), position in the mouth (anterior or posterior), and whether they were tooth bound (tooth bound or non– tooth bound). Study sites also were classified as small (≤ 13 mm) or large (> 13 mm) edentulous spans based on their mesiodistal dimensions. Patients were placed on prophylactic amoxicillin, 500 mg three times per day for 10 days, starting the day before surgery. If the patient was sensitive to amoxicillin, clindamycin, 300 mg four times per day for 10 days, was substituted. Patients rinsed with chlorhexidine 0.12% for 1 minute prior to surgery.
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77 Fig 1 (left) Representative site from treatment group 1, grafted with a 1:1 ratio of particulated autogenous bone and freezedried bone allograft (FDBA) in the posterior mandible. Occlusal view reveals 4 mm of existing alveolar ridge width and inadequate ridge width for placement of a standarddiameter implant at the mandibular right second premolar and first molar sites. Three titanium tenting screws have been placed to recreate the ideal ridge contour. Fig 2 (top right) Frontal view of right mandibular ramus shows the outline of the autogenous harvest site. Cortical cuts have been made using an ultrasonic bone saw. Fig 3 (middle right) Crushing autogenous blocks into 1- to 2-mm particles using doubleaction rongeurs in a bowl of saline. Fig 4 (bottom right) Autogenous bone and FDBA measured in a 1:1 ratio (by volume) for the combination graft using modified 1-mL syringes.
The same ridge augmentation technique was used in both treatment groups, with the exception of the grafting material. Following reflection of a mucoperiosteal flap, a gauged ridge-mapping caliper (Salvin Dental) was used to identify and measure the greatest horizontal alveolar ridge defect present at a point 3 mm apical to the alveolar crest. A 1.5-mm-diameter titanium reference screw (Pro-fix, Osteogenics Biomedical) was placed perpendicular to the alveolar ridge, extending laterally to the desired amount of horizontal augmentation.
The attempted horizontal gain was measured, to the nearest 0.5 mm, from the screw head to the bone using a UNC-15 periodontal probe. Additional screws were placed every 4 to 6 mm to re-create the ideal ridge form (Fig 1). Following cortical perforations with a ½ or 1 round bur, periosteal releasing incisions were made for tension-free advancement of the flap. In group 1, the particulate graft consisted of a 1:1 combination of FDBA (MinerOss Cortical & Cancellous, BioHorizons) and particulated autogenous bone, harvested from the mandibu-
lar external oblique ridge, ramus, or symphysis region using an ultrasonic bone saw (Piezosurgery, Mectron; Fig 2). The autogenous bone was crushed into 1- to 2-mm particles using double-action rongeurs in a bowl of saline (Fig 3). The 1:1 ratio of graft was measured by volume using two modified 1-mL syringes (Terumo; Fig 4) and applied to the recipient site using a bilayer technique with the autogenous particles placed against the native bone. The particulate bone graft was placed around supporting tenting screws to the level of the screw heads and covered
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Fig 5 Buccal view following cortical perforations and fixation of the AlloDerm GBR membrane apically with three titanium tacks (not visible).
Fig 6 Buccal view following placement of the combination graft around the tenting screws using a bilayer technique with the particulated autogenous bone placed against the native bone and veneered with MinerOss FDBA. The lateral extension of bone graft material intentionally ended at the level of the screw heads (no overbulking was performed).
Fig 7 Buccal view following fixation of the GBR membrane on the lingual aspect. Distobuccal membrane fixation tack is visible.
Fig 8 Sutured flap using horizontal mattress and interrupted sutures with 4-0 PTFE.
Fig 9 After 6 months, reentry surgery shows bone regeneration to the heads of the tenting screws and adequate alveolar ridge width to place standard-diameter implants.
Fig 10 Standard-diameter implants placed in augmented ridge.
with an acellular dermal matrix GBR membrane (AlloDerm GBR), which was fixed to the bone with titanium tacks (truTACK, ACE Surgical Supply) (Figs 5 to 7). Primary closure was obtained using a combination of interrupted and horizontal mattress sutures with 4-0 polytetrafluoro
ethylene (PTFE) sutures (Fig 8). In group 2, the particulate graft consisted of only FDBA with no autogenous graft harvesting. Patients returned for observation of wound healing and suture removal after 1 week and 3 weeks, and again for observation of wound heal-
ing 3 and 4 months postsurgery. Approximately 5 months after surgery, a second postoperative CBCT of the grafted sites was made. At approximately 6 months, a surgical reentry procedure was performed to make clinical study measurements (Fig 9) and place dental implants (Fig 10).
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79 The gain in alveolar horizontal ridge width was measured in a manner similar to that of the first surgery. If a standard-diameter dental implant(s) could be placed at the desired location, the GBR procedure was considered to be successful. An independent statistician performed all data analysis using Stata 13.1 software (StataCorp). Prior to the study, a power analysis was completed and determined that a sample size of 11 sites per group was sufficient to detect a mean difference in horizontal ridge width gain of 1.0 mm between the two treatment groups at the .05 level with a power of 80%. Treatment group comparisons were made in terms of patient age, initial ridge width healing time, horizontal ridge width gain via screw measurement, horizontal ridge width gain via caliper measurement, and graft resorption using two-sample Student t tests and Mann-Whitney U tests. Statistical analyses were performed both including and excluding sites with postoperative infections. For all comparisons, P < .05 was considered significant.
Results Twenty-seven partially edentulous patients enrolled in the study (Tables 1 to 5). Three patients were withdrawn from the study due to noncompliance. A total of 24 patients (4 men and 20 women, age range: 25 to 73 years; mean: 50.2 years) completed the study. Two patients received split-mouth treatment for a total of 26 sites. Two patients in the FDBA group and 1 patient in
Table 1 Patient characteristics and details of surgical sites treated with horizontal ridge augmentation for subsequent dental implant placement Patient no.
Age (y)
Sex
Site(s)*
Group†
1 2 3 4 5 6
55 67 56 66 57 31
M M F F M F
7 8 9 10 11‡ 12 13 14 15 16 17 18 19 20‡ 21 22 23
51 54 53 66 59 36 25 41 49 46 60 43 50 63 54 31 57
F F F F F F M F F F F F F F F F F
24 25 26‡ 27
32 52 66 73
M F F F
36 45, 46 36 22 36 45, 46 36 11, 12, 21, 22 46 46 14–16 31, 41, 42 45, 46 11 14, 15 22 21 36 21 24, 25 36, 37 34–36 36 45, 46 35, 36 12 31, 32, 41, 42 14, 15 46, 47
2 2 2 1 1 1 2 2 2 2 2 2 1 2 1 1 2 2 2 2 1 1 1 1 2 1 1 2 1
Graft healing Postoperative time (wk) infection 22 21 25 23 25 23 25 21 22 27 23 NR 21 21 21 23 24 29 21 21 NR 25 19 28 28 30 24 NR 29
No Yes No No Yes No No No No Yes No NR No No No No No No No No NR No No No No No No NR No
NR = not reported because of patient withdrawal. *Federation Dentaire Internationale tooth-numbering system. †Group 1 = combination graft; group 2 = FDBA alone. ‡Patient was withdrawn and excluded from the data analysis.
Table 2 Data analysis including postoperative infections Parameter Mean (SD) Median Interquartile range Range
Age (y)
Graft healing time (wk)
50.2 (12.6) 52.5 42 to 57 25 to 73
24.4 (2.83) 23.5 21.9 to 25.9 21.1 to 30.0
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Table 3 Clincal measurements (mm) before and after horizontal ridge augmentation Patient no. 1 2† 3 4 5† 6 7 8 9† 10 11‡ 12 13 14 15 16 17 18 19 20‡ 21 22 23 24 25 26‡ 27
Group*
Initial ridge width
Attempted gain
Ridge width at reentry
Ridge width gain
Graft resorption
Implants placed
2 2 2 1 1 1 2 2 2 2 2 2 1 2 1 1 2 2 2 2 1 1 1 1 2 1 1 2 1
5.0 5.0 4.0 1.5 6.5 4.5 3.5 1.0 3.5 2.5 3.5 4.0 4.0 1.0 2.0 4.0 2.5 4.0 4.0 3.5 5.0 6.0 6.0 4.0 3.0 3.5 3.0 3.0 3.5
4.0 3.5 4.0 5.0 4.0 3.5 4.0 4.0 4.0 4.0 3.0 4.0 4.0 5.0 4.0 3.0 4.0 4.0 3.0 3.0 4.0 3.0 3.0 4.0 3.0 4.0 4.0 5.0 4.0
8.0 6.0 6.5 5.0 7.5 8.0 7.5 4.0 6.0 3.0 6.0 NR 7.5 5.5 6.0 6.5 7.0 7.5 6.5 7.0 NR 9.0 9.0 6.5 6.0 6.5 7.0 NR 6.0
3.0 0.5† 3.5 3.5 1.0† 3.0 4.0 4.0 2.0 0.5† 2.5 NR 3.5 5.0 4.0 2.5 4.0 3.5 2.5 3.0 NR 3.0 3.0 2.5 3.0 3.0 4.0 NR 2.0
1.0 3.0 0.5 1.5 3.0 0.5 0.0 0.0 2.0 3.5 0.5 NR 0.5 0.0 0.0 0.5 0.0 0.5 0.5 0.0 NR 0.0 0.0 1.5 0.0 1.0 0.0 NR 2.0
Y N Y Y N Y Y Y Y N Y NR Y Y Y Y Y Y Y Y NR Y Y Y Y Y Y NR N§
NR = not reported because of patient withdrawal. *Group 1 = combination graft; group 2 = FDBA alone. †Patient experienced postoperative infections. ‡Patient was withdrawn due to noncompliance. §Patient had enough bone for implant placement but was unable to have the implant placed because of other restorative needs.
the combination group experienced acute postoperative infections during the first 3 weeks after grafting that resulted in the loss of the majority of the graft material and an inability to place standard-sized dental implants. Thirty-three standard-sized
dental implants were successfully placed in the remaining 23 treatment sites in 21 patients after a 24week graft healing period. Overall, the tenting screw technique with the GBR membrane demonstrated an average ridge width
gain of 2.92 ± 1.08 mm at reentry, including the three sites with postoperative infections (Table 6). When the three postoperative infections were excluded, the mean horizontal ridge width gain was 3.22 ± 0.74 mm (range, 2.0 to 5.0 mm).
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Table 4 Data analysis including postoperative infections (n = 26 sites)* Parameter Mean (SD)
Initial ridge width Attempted gain Ridge width at reentry Ridge width gain Graft resorption 3.63 (1.40)
3.77 (0.57)
6.58 (1.34)
2.92 (1.08)
0.85 (1.06)
Median
3.5
4.0
6.5
3.0
0.5
Interquartile range
3.0 to 4.0
3.0 to 4.0
6.0 to 7.5
2.5 to 3.5
0.0 to 1.5
Range
1.0 to 6.5
3.0 to 5.0
3.0 to 9.0
0.50 to 5.00
0.0 to 3.5
*All measurements are in millimeters.
Table 5 Data analysis excluding postoperative infections (n = 23 sites)* Parameter
Initial ridge width Attempted gain Ridge width at reentry Ridge width gain Graft resorption
Mean (SD)
3.50 (1.31)
3.76 (0.60)
6.72 (1.18)
3.22 (0.74)
0.54 (0.66)
Median
3.5
4.0
6.5
3.0
0.5
Interquartile range
3.0 to 4.0
3.0 to 4.0
6.0 to 7.5
2.5 to 4.0
0.0 to 1.0
Range
1.0 to 6.0
3.0 to 5.0
4.0 to 9.0
2.0 to 5.0
0.0 to 2.0
*All measurements are in millimeters.
Table 6 Treatment group comparisons of clinical measurements, excluding GBR failures (n = 23 sites) Comparison of group 1 to group 2 Mean (SD) Parameter Age (y) Healing time (wk) Initial ridge width (mm)* Attempted gain (mm)† Actual gain (mm)† Resorption (mm) Graft resorption (%)
Mann-Whitney U test
Student t test
Overall
Group 1 (n = 11)
Group 2 (n = 12)
Mean
48.95 (12.59) 24.34 (2.91) 3.50 (1.31)
47.45 (14.51) 24.65 (3.39) 3.82 (1.40)
49.50 (11.80) 23.85 (2.77) 3.21 (1.20)
–2.05 0.80 0.61
–13.5 to 9.4 –1.88 to 3.47 –0.52 to 1.74
.71 .54 .27
3.76 (0.60)
3.77 (0.61)
3.75 (0.62)
0.02
–0.51 to 0.56
.93
3.22 (0.74) 0.54 (0.66) 13.89 (16.0)
3.09 (0.63) 0.68 (0.72) 16.91 (17.10)
3.33 (0.83) 0.42 (0.60) 11.12 (15.11)
–0.24 0.27 5.79
–0.89 to 0.40 –0.30 to 0.84 –8.2 to 19.8
.44 .34 .40
95% CI
P
P
.36 .37
Group 1 = combination graft; group 2 = FDBA alone; CI = confidence interval. *Measurements made using a ridge-mapping caliper. †Measurements made using a UNC-15 periodontal probe relative to the head of the reference tenting screw.
The mean baseline ridge width of 3.50 ± 1.31 mm increased to 6.72 ± 1.18 mm. The overall mean attempted gain was 3.76 ± 0.60 mm. The mean graft resorption between baseline and reentry averaged 0.54 ± 0.66 mm or 13.89% ± 16.0%.
The horizontal ridge width gain of the treated sites was not affected by the following site-related factors: arch (maxillary vs mandibular; P = .31), location in the arch (anterior vs posterior; P = .10), size of the edentulous space (small vs large;
P = .62), or presence of adjacent teeth (tooth bound vs non–tooth bound edentulous space; P = .89). A comparison between the treatment groups showed no statistical difference in baseline ridge width (P = .27), attempted ridge
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82 width gain (P = .93), or healing time (P = .54) between the treatment groups. The allograft alone group showed similar average horizontal ridge width gains (3.33 ± 0.83 mm) to the combination graft group (3.09 ± 0.63 mm; P = .44) at reentry. Mean graft resorption was similar between the two treatment groups measured linearly (P = .36) and as a percentage of attempted gain in ridge width (P = .37).
Discussion To the best of the authors’ knowledge, this is the first randomized prospective study comparing the clinical differences in horizontal ridge width gain between an allograft alone and a combination particulate autogenous/allograft for lateral ridge augmentation using a fixed acellular dermal matrix GBR membrane and tenting screws. The results indicate that the addition of particulate autogenous bone to an allograft does not provide any clinical benefit over allograft alone for horizontal alveolar ridge augmentation. In the present study, GBR success was defined as the ability to place a standard-diameter dental implant at the prescribed restorative position at reentry. Of the 26 treatment sites in the 24 patients who completed the study, 23 sites had successful GBR outcomes. Two sites in the FDBA group and 1 site in the combination group experienced early postoperative infections that resulted in near-complete loss of the grafted materials and
were considered failures. This represented a 12.5% infection rate of treatment sites. A systematic review by Jensen and Terheyden reported an 18.9% complication rate with GBR procedures using resorbable membranes; however, the authors did not differentiate between infections and other complications.7 When the three infectionrelated failures were excluded, the current study demonstrated an average horizontal ridge width gain of 3.22 mm after a 24-week graft healing period. The average gain in horizontal ridge width for this study was slightly less than the 3.6 mm reported in the systematic review by Jensen and Terheyden.7 The decreased mean in horizontal ridge width gains found in the current study could have been due to the lack of overbulking the grafts beyond the ideal ridge form. The use of tenting screws in this study resulted in significantly less graft resorption compared with other GBR studies using particulate without tenting screws. At reentry, there was only 13% graft resorption, with no statistical differences between treatment groups. The only other study reporting a graft resorption rate was done by Sterio et al using a mineralized bone allograft (Puros, Zimmer Dental) and a resorbable bovine pericardium membrane without tenting screws. They reported a mean clinical graft resorption of 66.6% at 6 months after augmentation.11 It is possible that the use of tenting screws and membrane fixation could have contributed to the minimal resorption measured in the current study.
The present study found no significant difference in average horizontal ridge width gain at reentry between the combination group and FDBA-alone group (3.33 versus 3.09 mm; P = .44). These findings are in agreement with Beitlitum et al.29 Within the limitations of this study, the addition of particulated autogenous bone to FDBA did not provide any clinical benefit in the amount of bone formation over using FDBA alone for horizontal alveolar ridge augmentation procedures. One of the limitations of this study is the lack of histologic comparison between treatment groups. Additional research is required to determine if the addition of particulated autogenous bone results in a faster regenerative process and/or increased graft density.
Conclusions Horizontal alveolar ridge augmentation using a tenting screw technique with particulate grafts, tenting screws, and a fixed acellular dermal matrix membrane is a successful and predictable approach to regenerating atrophic alveolar ridges.
Acknowledgments The authors reported no conflicts of interest related to this study.
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83 References 1. Hammerle CH, Jung RE, Feloutzis A. A systematic review of the survival of implants in bone sites augmented with barrier membranes (guided bone regeneration) in partially edentulous patients. J Clin Periodontol 2002;29(suppl 3):226–231. 2. McAllister BS, Haghighat K. Bone augmentation techniques. J Periodontol 2007; 78:377–396. 3. Nevins M, Mellonig JT. The advantages of localized ridge augmentation prior to implant placement: A staged event. Int J Periodontics Restorative Dent 1994;14: 96–111. 4. Clementini M, Morlupi A, Canullo L, Agrestini C, Barlattani A. Success rate of dental implants inserted in horizontal and vertical guided bone regenerated areas: A systematic review. Int J Oral Maxillofac Surg 2012;41:847–852. 5. Aghaloo TL, Moy PK. Which hard tissue augmentation techniques are the most successful in furnishing bony support for implant placement? Int J Oral Maxillofac Implants 2007;22(suppl):49–70. 6. Esposito M, Grusovin MG, Felice P, Karatzopoulos G, Worthington HV, Coulthard P. The efficacy of horizontal and vertical bone augmentation procedures for dental implants—A Cochrane systematic review. Eur J Oral Implantol 2009;2: 167–184. 7. Jensen SS, Terheyden H. Bone augmentation procedures in localized defects in the alveolar ridge: Clinical results with different bone grafts and bone-substitute materials. Int J Oral Maxillofac Implants 2009;24(suppl):218–236. 8. Buser D, Dula K, Hirt HP, Schenk RK. Lateral ridge augmentation using autografts and barrier membranes: A clinical study with 40 partially edentulous patients. J Oral Maxillofac Surg 1996;54:420–432. 9. Buser D, Dula K, Hess D, Hirt HP, Belser UC. Localized ridge augmentation with autografts and barrier membranes. Periodontol 2000 1999;19:151–163. 10. Simion M, Fontana F, Rasperini G, Maiorana C. Vertical ridge augmentation by expanded-polytetrafluoroethylene membrane and a combination of intraoral autogenous bone graft and deproteinized anorganic bovine bone (Bio-Oss). Clin Oral Implants Res 2007;18:620–629. 11. Sterio TW, Katancik JA, Blanchard SB, Xenoudi P, Mealey BL. A prospective, multicenter study of bovine pericardium membrane with cancellous particulate allograft for localized alveolar ridge augmentation. Int J Periodontics Restorative Dent 2013;33:499–507.
12. Urban IA, Nagursky H, Lozada JL, Nagy K. Horizontal ridge augmentation with a collagen membrane and a combination of particulated autogenous bone and anorganic bovine bone-derived mineral: A prospective case series in 25 patients. Int J Periodontics Restorative Dent 2013; 33:299–307. 13. Feuille F, Knapp CI, Brunsvold MA, Mellonig JT. Clinical and histologic evaluation of bone-replacement grafts in the treatment of localized alveolar ridge defects. Part 1: Mineralized freeze-dried bone allograft. Int J Periodontics Restorative Dent 2003;23:29–35. 14. Griffin TJ, Cheung WS, Hirayama H. Hard and soft tissue augmentation in implant therapy using acellular dermal matrix. Int J Periodontics Restorative Dent 2004;24: 352–361. 15. Fowler EB, Breault LG, Rebitski G. Ridge preservation utilizing an acellular dermal allograft and demineralized freeze-dried bone allograft: Part II. Immediate endosseous implant placement. J Periodontol 2000;71:1360–1364. 16. Borges GJ, Novaes AB Jr, Grisi MF, Palioto DB, Taba M Jr, de Souza SL. Acellular dermal matrix as a barrier in guided bone regeneration: A clinical, radiographic and histomorphometric study in dogs. Clin Oral Implants Res 2009;20:1105–1115. 17. Sudarsan S, Arun KV, Priya MS, Arun R. Clinical and histological evaluation of alloderm GBR and BioOss in the treatment of Siebert’s class I ridge deficiency. J Indian Soc Periodontol 2008;12:73–78. 18. Pellegrini G, Pagni G, Rasperini G. Surgical approaches based on biological objectives: GTR versus GBR techniques. Int J Dent 2013;2013:521547. 19. Polimeni G, Koo KT, Qahash M, Xiropaidis AV, Albandar JM, Wikesjo UM. Prognostic factors for alveolar regeneration: Effect of a space-providing biomaterial on guided tissue regeneration. J Clin Periodontol 2004;31:725–729. 20. Simon BI, Chiang TF, Drew HJ. Alternative to the gold standard for alveolar ridge augmentation: Tenting screw technology. Quintessence Int 2010;41:379–386. 21. Langer B, Langer L, Sullivan RM. Vertical ridge augmentation procedure using guided bone regeneration, demineralized freeze-dried bone allograft, and miniscrews: 4- to 13-year observations on loaded implants. Int J Periodontics Restorative Dent 2010;30:227–235.
22. Le B, Rohrer MD, Prasad HS. Screw “tent-pole” grafting technique for reconstruction of large vertical alveolar ridge defects using human mineralized allograft for implant site preparation. J Oral Maxillofac Surg 2010;68:428–435. 23. Hempton TJ, Fugazzotto PA. Ridge augmentation utilizing guided tissue regeneration, titanium screws, freeze-dried bone, and tricalcium phosphate: clinical report. Implant Dent 1994;3:35–37. 24. Fugazzotto PA. Ridge augmentation with titanium screws and guided tissue regeneration: Technique and report of a case. Int J Oral Maxillofac Implants 1993;8: 335–339. 25. Becker W, Becker BE, McGuire MK. Localized ridge augmentation using absorbable pins and e-PTFE barrier membranes: A new surgical technique. Case reports. Int J Periodontics Restorative Dent 1994;14:48–61. 26. Goldberg VM, Stevenson S. Natural history of autografts and allografts. Clin Orthop Relat Res 1987:7–16. 27. Misch CM. Comparison of intraoral donor sites for onlay grafting prior to implant placement. Int J Oral Maxillofac Implants 1997;12:767–776. 28. Capelli M. Autogenous bone graft from the mandibular ramus: A technique for bone augmentation. Int J Periodontics Restorative Dent 2003;23:277–285. 29. Beitlitum I, Artzi Z, Nemcovsky CE. Clinical evaluation of particulate allogeneic with and without autogenous bone grafts and resorbable collagen membranes for bone augmentation of atrophic alveolar ridges. Clin Oral Implants Res 2010;21: 1242–1250. 30. Toscano N, Holtzclaw D, Mazor Z, Rosen P, Horowitz R, Toffler M. Horizontal ridge augmentation utilizing a composite graft of demineralized freeze-dried allograft, mineralized cortical cancellous chips, and a biologically degradable thermoplastic carrier combined with a resorbable membrane: A retrospective evaluation of 73 consecutively treated cases from private practices. J Oral Implantol 2010;36: 467–474. 31. Wang HL, Misch C, Neiva RF. “Sandwich” bone augmentation technique: Rationale and report of pilot cases. Int J Periodontics Restorative Dent 2004;24:232–245.
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Lateral Alveolar Ridge Augmentation Using Tenting Screws, Acellular Dermal Matrix, and Freeze-Dried Bone Allograft Alone or with Particulate Autogenous Bone Gregory R. Caldwell, DDS, MS1 Michael P. Mills, DMD, MS2 Richard Finlayson, DDS2 Brian L. Mealey, DDS, MS3
This randomized prospective study evaluated the clinical benefits of using a corticocancellous mixture of freeze-dried bone allograft alone or in combination (1:1) with particulated autogenous bone for horizontal ridge augmentation and subsequent implant placement. Twenty-four patients with atrophic ridges received lateral ridge augmentations with particulate grafts placed around tenting screws and covered with a fixed acellular dermal matrix membrane. Thirty-three standard-diameter implants were successfully placed in 21 patients after a 24-week graft healing period. Three patients experienced early postoperative infections following the grafting procedure (12.5% of sites). At reentry, the allograft alone group showed similar average horizontal ridge width gains (3.33 ± 0.83 mm) to the combination group (3.09 ± 0.63 mm; P = .44). The mean graft resorption between baseline and reentry averaged 13.89%. (Int J Periodontics Restorative Dent 2015;35:75–83. doi: 10.11607/prd.2260)
Private Practice, El Paso, Texas, USA. Clinical Associate Professor, Department of Periodontics, University of Texas Health Science Center San Antonio, San Antonio, Texas, USA. 3Professor and Graduate Program Director, Department of Periodontics, University of Texas Health Science Center at San Antonio, San Antonio, Texas, USA. 1 2
Correspondence to: Dr Gregory Caldwell, Caldwell & Dimmitt Periodontics, 9398 Viscount Bldg. 1-A, El Paso, TX 79925, USA; fax: 915-593-7478; email: [email protected]. ©2015 by Quintessence Publishing Co Inc.
The success of implant dentistry has been largely related to the advent of bone augmentation techniques that allow for the regeneration of atrophic alveolar ridges into an ideal ridge form and for placement of implants in their ideal functional and esthetic positions.1–4 The current practice for ridge augmentation consists of a variety of techniques, including particulate grafts, onlay block grafts, ridge splitting, distraction osteogenesis, or a combination of these techniques.2,5–7 Guided bone regeneration (GBR) studies utilizing both nonresorbable and resorbable membranes have shown great success with horizontal alveolar ridge augmentation.2,5–13 Resorbable membranes are typically made of polyesters or tissue-derived collagens from human and animal sources.2 Acelluar dermal matrix (AlloDerm, LifeCell) has been successfully used for root coverage, thickening of soft tissues, and GBR.14–17 AlloDerm GBR (BioHorizons) is a thinner version (thickness, 0.5 to 0.9 mm) of the original AlloDerm product (thickness, 0.9 to 1.6 mm), specifically designed for GBR.
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76 Aside from soft tissue exclusion and clot stability, space maintenance is key to the success of GBR and can be accomplished in various ways using titanium-reinforced nonresorbable membranes, titanium mesh, particulate grafts and/ or block grafts, dental implants, or tenting screws.2,7,8,10,18–20 Nonresorbable2,20–24 and resorbable tenting screws25 have been used to aid in space maintenance, decrease graft mobility, and relieve external pressure on the graft. Autogenous bone is still considered by many to be the gold standard graft material for GBR because of its osteogenic, osteoinductive, and osteoconductive properties.7,26 Autogenous bone is commonly harvested from the ramus and symphysis but has been associated with increased patient morbidity.2,27,28 As an alternative to autogenous grafts, various bone substitutes, including xenografts, alloplasts, and allografts are used as adjuncts for GBR with successful clinical and histologic outcomes.7,13,21 However, some have advocated mixing autogenous bone with the various bone substitutes in order to combine the osteogenic and osteoinductive growth factors of autogenous bone with the osteoconductive properties of a bone substitute.10,12,29,30 Others have advocated applying the combination graft using a bilayer or sandwich technique with the most osteogenic or osteoinductive grafting material placed against the native bone and covered by an osteoconductive graft for space maintenance.29,31
Only one nonrandomized human study has compared the clinical outcomes of GBR procedures in atrophic ridges using particulate freeze-dried bone allograft (FDBA) alone or in combination with particulate autogenous bone using a bilayer technique.29 This study found no statistical difference in horizontal and/or vertical bone formation between treatment groups but had several weaknesses, including a high spontaneous membrane exposure rate (24%), lack of randomization and standardization between treatment groups, and imprecise ridge width gain measurement techniques. The purpose of the present study was to further evaluate the clinical benefits, or lack thereof, of using an allograft alone or in combination (1:1) with particulated autogenous bone for horizontal ridge augmentation and subsequent implant placement.
Method and materials This was a nonmasked, randomized, prospective clinical trial. Twenty-seven systemically healthy partially edentulous patients who were referred to the University of Texas Health Science Center at San Antonio Graduate Periodontics Clinic for lateral ridge augmentation and dental implant placement were included in the study. Eleven periodontics residents under direct supervision of board-certified periodontics faculty completed the surgical procedures between April 2012 and January 2014. The
principal investigator (GRC) or coprincipal investigator (BLM) was present for all of the surgical procedures and made all of the intraoperative study measurements. Study sites were required to exhibit a partially edentulous ridge with inadequate buccolingual dimension for the placement of a standarddiameter dental implant, as measured clinically and radiographically using cone beam computed tomography (CBCT). Exclusion criteria included heavy smoking (>10 cigarettes per day), active periodontal disease, uncontrolled systemic diseases, infectious diseases, pregnancy, or a history of bone-altering medications that could interfere with the treatment. Following enrollment and written consent, patients were randomized into a treatment group by selecting from a group of sealed envelopes, each containing a piece of paper labeled either “Group 1: Autogenous + FDBA” or “Group 2: FDBA.” Study sites were classified based on arch (maxillary or mandibular), position in the mouth (anterior or posterior), and whether they were tooth bound (tooth bound or non– tooth bound). Study sites also were classified as small (≤ 13 mm) or large (> 13 mm) edentulous spans based on their mesiodistal dimensions. Patients were placed on prophylactic amoxicillin, 500 mg three times per day for 10 days, starting the day before surgery. If the patient was sensitive to amoxicillin, clindamycin, 300 mg four times per day for 10 days, was substituted. Patients rinsed with chlorhexidine 0.12% for 1 minute prior to surgery.
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77 Fig 1 (left) Representative site from treatment group 1, grafted with a 1:1 ratio of particulated autogenous bone and freezedried bone allograft (FDBA) in the posterior mandible. Occlusal view reveals 4 mm of existing alveolar ridge width and inadequate ridge width for placement of a standarddiameter implant at the mandibular right second premolar and first molar sites. Three titanium tenting screws have been placed to recreate the ideal ridge contour. Fig 2 (top right) Frontal view of right mandibular ramus shows the outline of the autogenous harvest site. Cortical cuts have been made using an ultrasonic bone saw. Fig 3 (middle right) Crushing autogenous blocks into 1- to 2-mm particles using doubleaction rongeurs in a bowl of saline. Fig 4 (bottom right) Autogenous bone and FDBA measured in a 1:1 ratio (by volume) for the combination graft using modified 1-mL syringes.
The same ridge augmentation technique was used in both treatment groups, with the exception of the grafting material. Following reflection of a mucoperiosteal flap, a gauged ridge-mapping caliper (Salvin Dental) was used to identify and measure the greatest horizontal alveolar ridge defect present at a point 3 mm apical to the alveolar crest. A 1.5-mm-diameter titanium reference screw (Pro-fix, Osteogenics Biomedical) was placed perpendicular to the alveolar ridge, extending laterally to the desired amount of horizontal augmentation.
The attempted horizontal gain was measured, to the nearest 0.5 mm, from the screw head to the bone using a UNC-15 periodontal probe. Additional screws were placed every 4 to 6 mm to re-create the ideal ridge form (Fig 1). Following cortical perforations with a ½ or 1 round bur, periosteal releasing incisions were made for tension-free advancement of the flap. In group 1, the particulate graft consisted of a 1:1 combination of FDBA (MinerOss Cortical & Cancellous, BioHorizons) and particulated autogenous bone, harvested from the mandibu-
lar external oblique ridge, ramus, or symphysis region using an ultrasonic bone saw (Piezosurgery, Mectron; Fig 2). The autogenous bone was crushed into 1- to 2-mm particles using double-action rongeurs in a bowl of saline (Fig 3). The 1:1 ratio of graft was measured by volume using two modified 1-mL syringes (Terumo; Fig 4) and applied to the recipient site using a bilayer technique with the autogenous particles placed against the native bone. The particulate bone graft was placed around supporting tenting screws to the level of the screw heads and covered
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Fig 5 Buccal view following cortical perforations and fixation of the AlloDerm GBR membrane apically with three titanium tacks (not visible).
Fig 6 Buccal view following placement of the combination graft around the tenting screws using a bilayer technique with the particulated autogenous bone placed against the native bone and veneered with MinerOss FDBA. The lateral extension of bone graft material intentionally ended at the level of the screw heads (no overbulking was performed).
Fig 7 Buccal view following fixation of the GBR membrane on the lingual aspect. Distobuccal membrane fixation tack is visible.
Fig 8 Sutured flap using horizontal mattress and interrupted sutures with 4-0 PTFE.
Fig 9 After 6 months, reentry surgery shows bone regeneration to the heads of the tenting screws and adequate alveolar ridge width to place standard-diameter implants.
Fig 10 Standard-diameter implants placed in augmented ridge.
with an acellular dermal matrix GBR membrane (AlloDerm GBR), which was fixed to the bone with titanium tacks (truTACK, ACE Surgical Supply) (Figs 5 to 7). Primary closure was obtained using a combination of interrupted and horizontal mattress sutures with 4-0 polytetrafluoro
ethylene (PTFE) sutures (Fig 8). In group 2, the particulate graft consisted of only FDBA with no autogenous graft harvesting. Patients returned for observation of wound healing and suture removal after 1 week and 3 weeks, and again for observation of wound heal-
ing 3 and 4 months postsurgery. Approximately 5 months after surgery, a second postoperative CBCT of the grafted sites was made. At approximately 6 months, a surgical reentry procedure was performed to make clinical study measurements (Fig 9) and place dental implants (Fig 10).
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79 The gain in alveolar horizontal ridge width was measured in a manner similar to that of the first surgery. If a standard-diameter dental implant(s) could be placed at the desired location, the GBR procedure was considered to be successful. An independent statistician performed all data analysis using Stata 13.1 software (StataCorp). Prior to the study, a power analysis was completed and determined that a sample size of 11 sites per group was sufficient to detect a mean difference in horizontal ridge width gain of 1.0 mm between the two treatment groups at the .05 level with a power of 80%. Treatment group comparisons were made in terms of patient age, initial ridge width healing time, horizontal ridge width gain via screw measurement, horizontal ridge width gain via caliper measurement, and graft resorption using two-sample Student t tests and Mann-Whitney U tests. Statistical analyses were performed both including and excluding sites with postoperative infections. For all comparisons, P < .05 was considered significant.
Results Twenty-seven partially edentulous patients enrolled in the study (Tables 1 to 5). Three patients were withdrawn from the study due to noncompliance. A total of 24 patients (4 men and 20 women, age range: 25 to 73 years; mean: 50.2 years) completed the study. Two patients received split-mouth treatment for a total of 26 sites. Two patients in the FDBA group and 1 patient in
Table 1 Patient characteristics and details of surgical sites treated with horizontal ridge augmentation for subsequent dental implant placement Patient no.
Age (y)
Sex
Site(s)*
Group†
1 2 3 4 5 6
55 67 56 66 57 31
M M F F M F
7 8 9 10 11‡ 12 13 14 15 16 17 18 19 20‡ 21 22 23
51 54 53 66 59 36 25 41 49 46 60 43 50 63 54 31 57
F F F F F F M F F F F F F F F F F
24 25 26‡ 27
32 52 66 73
M F F F
36 45, 46 36 22 36 45, 46 36 11, 12, 21, 22 46 46 14–16 31, 41, 42 45, 46 11 14, 15 22 21 36 21 24, 25 36, 37 34–36 36 45, 46 35, 36 12 31, 32, 41, 42 14, 15 46, 47
2 2 2 1 1 1 2 2 2 2 2 2 1 2 1 1 2 2 2 2 1 1 1 1 2 1 1 2 1
Graft healing Postoperative time (wk) infection 22 21 25 23 25 23 25 21 22 27 23 NR 21 21 21 23 24 29 21 21 NR 25 19 28 28 30 24 NR 29
No Yes No No Yes No No No No Yes No NR No No No No No No No No NR No No No No No No NR No
NR = not reported because of patient withdrawal. *Federation Dentaire Internationale tooth-numbering system. †Group 1 = combination graft; group 2 = FDBA alone. ‡Patient was withdrawn and excluded from the data analysis.
Table 2 Data analysis including postoperative infections Parameter Mean (SD) Median Interquartile range Range
Age (y)
Graft healing time (wk)
50.2 (12.6) 52.5 42 to 57 25 to 73
24.4 (2.83) 23.5 21.9 to 25.9 21.1 to 30.0
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Table 3 Clincal measurements (mm) before and after horizontal ridge augmentation Patient no. 1 2† 3 4 5† 6 7 8 9† 10 11‡ 12 13 14 15 16 17 18 19 20‡ 21 22 23 24 25 26‡ 27
Group*
Initial ridge width
Attempted gain
Ridge width at reentry
Ridge width gain
Graft resorption
Implants placed
2 2 2 1 1 1 2 2 2 2 2 2 1 2 1 1 2 2 2 2 1 1 1 1 2 1 1 2 1
5.0 5.0 4.0 1.5 6.5 4.5 3.5 1.0 3.5 2.5 3.5 4.0 4.0 1.0 2.0 4.0 2.5 4.0 4.0 3.5 5.0 6.0 6.0 4.0 3.0 3.5 3.0 3.0 3.5
4.0 3.5 4.0 5.0 4.0 3.5 4.0 4.0 4.0 4.0 3.0 4.0 4.0 5.0 4.0 3.0 4.0 4.0 3.0 3.0 4.0 3.0 3.0 4.0 3.0 4.0 4.0 5.0 4.0
8.0 6.0 6.5 5.0 7.5 8.0 7.5 4.0 6.0 3.0 6.0 NR 7.5 5.5 6.0 6.5 7.0 7.5 6.5 7.0 NR 9.0 9.0 6.5 6.0 6.5 7.0 NR 6.0
3.0 0.5† 3.5 3.5 1.0† 3.0 4.0 4.0 2.0 0.5† 2.5 NR 3.5 5.0 4.0 2.5 4.0 3.5 2.5 3.0 NR 3.0 3.0 2.5 3.0 3.0 4.0 NR 2.0
1.0 3.0 0.5 1.5 3.0 0.5 0.0 0.0 2.0 3.5 0.5 NR 0.5 0.0 0.0 0.5 0.0 0.5 0.5 0.0 NR 0.0 0.0 1.5 0.0 1.0 0.0 NR 2.0
Y N Y Y N Y Y Y Y N Y NR Y Y Y Y Y Y Y Y NR Y Y Y Y Y Y NR N§
NR = not reported because of patient withdrawal. *Group 1 = combination graft; group 2 = FDBA alone. †Patient experienced postoperative infections. ‡Patient was withdrawn due to noncompliance. §Patient had enough bone for implant placement but was unable to have the implant placed because of other restorative needs.
the combination group experienced acute postoperative infections during the first 3 weeks after grafting that resulted in the loss of the majority of the graft material and an inability to place standard-sized dental implants. Thirty-three standard-sized
dental implants were successfully placed in the remaining 23 treatment sites in 21 patients after a 24week graft healing period. Overall, the tenting screw technique with the GBR membrane demonstrated an average ridge width
gain of 2.92 ± 1.08 mm at reentry, including the three sites with postoperative infections (Table 6). When the three postoperative infections were excluded, the mean horizontal ridge width gain was 3.22 ± 0.74 mm (range, 2.0 to 5.0 mm).
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Table 4 Data analysis including postoperative infections (n = 26 sites)* Parameter Mean (SD)
Initial ridge width Attempted gain Ridge width at reentry Ridge width gain Graft resorption 3.63 (1.40)
3.77 (0.57)
6.58 (1.34)
2.92 (1.08)
0.85 (1.06)
Median
3.5
4.0
6.5
3.0
0.5
Interquartile range
3.0 to 4.0
3.0 to 4.0
6.0 to 7.5
2.5 to 3.5
0.0 to 1.5
Range
1.0 to 6.5
3.0 to 5.0
3.0 to 9.0
0.50 to 5.00
0.0 to 3.5
*All measurements are in millimeters.
Table 5 Data analysis excluding postoperative infections (n = 23 sites)* Parameter
Initial ridge width Attempted gain Ridge width at reentry Ridge width gain Graft resorption
Mean (SD)
3.50 (1.31)
3.76 (0.60)
6.72 (1.18)
3.22 (0.74)
0.54 (0.66)
Median
3.5
4.0
6.5
3.0
0.5
Interquartile range
3.0 to 4.0
3.0 to 4.0
6.0 to 7.5
2.5 to 4.0
0.0 to 1.0
Range
1.0 to 6.0
3.0 to 5.0
4.0 to 9.0
2.0 to 5.0
0.0 to 2.0
*All measurements are in millimeters.
Table 6 Treatment group comparisons of clinical measurements, excluding GBR failures (n = 23 sites) Comparison of group 1 to group 2 Mean (SD) Parameter Age (y) Healing time (wk) Initial ridge width (mm)* Attempted gain (mm)† Actual gain (mm)† Resorption (mm) Graft resorption (%)
Mann-Whitney U test
Student t test
Overall
Group 1 (n = 11)
Group 2 (n = 12)
Mean
48.95 (12.59) 24.34 (2.91) 3.50 (1.31)
47.45 (14.51) 24.65 (3.39) 3.82 (1.40)
49.50 (11.80) 23.85 (2.77) 3.21 (1.20)
–2.05 0.80 0.61
–13.5 to 9.4 –1.88 to 3.47 –0.52 to 1.74
.71 .54 .27
3.76 (0.60)
3.77 (0.61)
3.75 (0.62)
0.02
–0.51 to 0.56
.93
3.22 (0.74) 0.54 (0.66) 13.89 (16.0)
3.09 (0.63) 0.68 (0.72) 16.91 (17.10)
3.33 (0.83) 0.42 (0.60) 11.12 (15.11)
–0.24 0.27 5.79
–0.89 to 0.40 –0.30 to 0.84 –8.2 to 19.8
.44 .34 .40
95% CI
P
P
.36 .37
Group 1 = combination graft; group 2 = FDBA alone; CI = confidence interval. *Measurements made using a ridge-mapping caliper. †Measurements made using a UNC-15 periodontal probe relative to the head of the reference tenting screw.
The mean baseline ridge width of 3.50 ± 1.31 mm increased to 6.72 ± 1.18 mm. The overall mean attempted gain was 3.76 ± 0.60 mm. The mean graft resorption between baseline and reentry averaged 0.54 ± 0.66 mm or 13.89% ± 16.0%.
The horizontal ridge width gain of the treated sites was not affected by the following site-related factors: arch (maxillary vs mandibular; P = .31), location in the arch (anterior vs posterior; P = .10), size of the edentulous space (small vs large;
P = .62), or presence of adjacent teeth (tooth bound vs non–tooth bound edentulous space; P = .89). A comparison between the treatment groups showed no statistical difference in baseline ridge width (P = .27), attempted ridge
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82 width gain (P = .93), or healing time (P = .54) between the treatment groups. The allograft alone group showed similar average horizontal ridge width gains (3.33 ± 0.83 mm) to the combination graft group (3.09 ± 0.63 mm; P = .44) at reentry. Mean graft resorption was similar between the two treatment groups measured linearly (P = .36) and as a percentage of attempted gain in ridge width (P = .37).
Discussion To the best of the authors’ knowledge, this is the first randomized prospective study comparing the clinical differences in horizontal ridge width gain between an allograft alone and a combination particulate autogenous/allograft for lateral ridge augmentation using a fixed acellular dermal matrix GBR membrane and tenting screws. The results indicate that the addition of particulate autogenous bone to an allograft does not provide any clinical benefit over allograft alone for horizontal alveolar ridge augmentation. In the present study, GBR success was defined as the ability to place a standard-diameter dental implant at the prescribed restorative position at reentry. Of the 26 treatment sites in the 24 patients who completed the study, 23 sites had successful GBR outcomes. Two sites in the FDBA group and 1 site in the combination group experienced early postoperative infections that resulted in near-complete loss of the grafted materials and
were considered failures. This represented a 12.5% infection rate of treatment sites. A systematic review by Jensen and Terheyden reported an 18.9% complication rate with GBR procedures using resorbable membranes; however, the authors did not differentiate between infections and other complications.7 When the three infectionrelated failures were excluded, the current study demonstrated an average horizontal ridge width gain of 3.22 mm after a 24-week graft healing period. The average gain in horizontal ridge width for this study was slightly less than the 3.6 mm reported in the systematic review by Jensen and Terheyden.7 The decreased mean in horizontal ridge width gains found in the current study could have been due to the lack of overbulking the grafts beyond the ideal ridge form. The use of tenting screws in this study resulted in significantly less graft resorption compared with other GBR studies using particulate without tenting screws. At reentry, there was only 13% graft resorption, with no statistical differences between treatment groups. The only other study reporting a graft resorption rate was done by Sterio et al using a mineralized bone allograft (Puros, Zimmer Dental) and a resorbable bovine pericardium membrane without tenting screws. They reported a mean clinical graft resorption of 66.6% at 6 months after augmentation.11 It is possible that the use of tenting screws and membrane fixation could have contributed to the minimal resorption measured in the current study.
The present study found no significant difference in average horizontal ridge width gain at reentry between the combination group and FDBA-alone group (3.33 versus 3.09 mm; P = .44). These findings are in agreement with Beitlitum et al.29 Within the limitations of this study, the addition of particulated autogenous bone to FDBA did not provide any clinical benefit in the amount of bone formation over using FDBA alone for horizontal alveolar ridge augmentation procedures. One of the limitations of this study is the lack of histologic comparison between treatment groups. Additional research is required to determine if the addition of particulated autogenous bone results in a faster regenerative process and/or increased graft density.
Conclusions Horizontal alveolar ridge augmentation using a tenting screw technique with particulate grafts, tenting screws, and a fixed acellular dermal matrix membrane is a successful and predictable approach to regenerating atrophic alveolar ridges.
Acknowledgments The authors reported no conflicts of interest related to this study.
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