e1
Block Versus Particulate/Titanium Mesh for Ridge Augmentation for Mandibular Lateral Incisor Defects: Clinical and Histologic Analysis Salvatore D’Amato, MD, DDS1 Gianpaolo Tartaro, MDS2 Angelo Itro, MD, DDS3 Livia Nastri, DDS, PhD4 Mario Santagata, MD, PhD5 The purpose of this study was to clinically, histologically, and immunohistochemically evaluate the quantity and quality of newly regenerated bone by means of direct clinical measuring and biopsy specimens of alveolar ridges augmented by autogenous cortical bone or titanium micromesh—both filled with autogenous particulate bone graft in the anterior jaws. For the preliminary study, 10 alveolar bone defects in five partially edentulous patients (two men and three women), between 19 and 35 years old (mean: 25.4, SD: 5.94) were selected. Bone defects were randomly (coin toss) divided into two groups: A (micromesh) and B (bone block). The donor site was the mandibular symphysis in all cases. On the return appointment, operative grafts appeared well incorporated into the native bone, which suggests that good contact and fit between the graft and the recipient site had been obtained during the first surgery. Histologic investigations confirmed excellent integration and revascularization of the graft in both study groups, with formation of new bone tissue without any relevant inflammation. (Int J Periodontics Restorative Dent 2015;35:e1–e8. doi: 10.11607/prd.2073)
Aggregate Professor Maxillofacial Surgery, Division of Oral and Maxillofacial Surgery, Multidisciplinary Department of Medical and Dental Specialties, AOU—Second University of Naples, Naples, Italy. 2Head of Maxillofacial Surgery, Division of Oral and Maxillofacial Surgery, Multidisciplinary Department of Medical and Dental Specialties, AOU—Second University of Naples, Naples, Italy. 3Director of Multidisciplinary Department of Medical and Dental Specialities, Division of Oral and Maxillofacial Surgery, Multidisciplinary Department of Medical and Dental Specialties, AOU—Second University of Naples, Naples, Italy. 4Aggregate Professor of Periodontology, Division of Oral and Maxillofacial Surgery, Multidisciplinary Department of Medical and Dental Specialties, AOU—Second University of Naples, Naples, Italy. 5Assistant Professor, Division of Oral and Maxillofacial Surgery, Multidisciplinary Department of Medical and Dental Specialties, AOU–Second University of Naples, Naples, Italy. 1
Correspondence to: Dr Salvatore D’Amato, B. Croce, 18 80059, Torre del Greco Napoli, Italy; email: [email protected]. ©2015 by Quintessence Publishing Co Inc.
The reconstruction of alveolar ridges for implant placement is still a challenging surgical procedure, especially in cases of extensive vertical and horizontal bone atrophy. A number of surgical procedures have been used to reconstruct the alveolar crest, including “split-ridge” (osteotomy for lateral expansion)1–4; osteodistraction; bone grafting with various grafting materials (autogenous bone, allograft, xenograft, and alloplastic materials); guided bone regeneration (GBR), alone or in combination with grafting materials1–9; and other techniques.10–14 One of the major challenges, however, is to minimize the resorption of grafted bone. Titanium (Ti) mesh was first introduced for the reconstruction of large osseous defects by Boyne15 and was later proposed for osseous restoration of deficient edentulous maxillary ridges.16,17 In 1996, von Arx et al18 introduced Ti micromesh for reconstructive implant surgery and reported positive results for a staged approach (ridge augmentation performed before implant placement) and a simultaneous procedure (implant placement and ridge
Volume 35, Number 1, 2015 © 2015 BY QUINTESSENCE PUBLISHING CO, INC. PRINTING OF THIS DOCUMENT IS RESTRICTED TO PERSONAL USE ONLY. NO PART MAY BE REPRODUCED OR TRANSMITTED IN ANY FORM WITHOUT WRITTEN PERMISSION FROM THE PUBLISHER.
e2 Randomization
Table 1 Patient distribution Patient 1 2 3 4 5
Age (y)
Sex
Titanium mesh
Cortical bone
19 23 26 24 35
F F M M F
Right side Right side Left side Left side Left side
Left side Left side Right side Right side Right side
augmentation performed at the same time). Recent clinical studies have confirmed the reliability of this technique.19–21 Few reports in the literature address histologic evidence in humans of the results obtained by using Ti mesh for localized alveolar ridge augmentation.22 Therefore, the purpose of this study was to clinically, histologically, and immunohistochemically evaluate the quantity and quality of newly regenerated bone for mandibular lateral incisor defects employing and comparing two different techniques: autogenous cortical bone graft versus Ti micromesh, both filled with autogenous particulate bone.
performed at baseline, including a study cast, periapical or panoramic radiographs, and cone beam computed tomography (CBCT) scan. The main inclusion criterion was the presence of a bilateral agenesis of the mandibular lateral incisors with a horizontal bone defect of at least 3 mm (CBCT scan) insufficient for correct prosthetic implant positioning. In addition, patients had to agree to participate in a postoperative follow-up program and to sign an informed consent form. The exclusion criteria were as follows: • • •
Method and materials • Selection of patients
Ten alveolar bone defects related to a missing mandibular lateral incisor were selected in five partially edentulous patients from those referred to Second University of Naples, Multidisciplinary Department of Medical-Surgical and Dental Specialties. After a medical history interview and clinical examination, all patients received a prophylaxis session. A preoperative evaluation was
• • • • • • •
Local infection Smoking (more than 10 cigarettes per day) Uncontrolled diabetes (HbA1c > 53 mmol/mol) Previous radiotherapy in head and neck region Chemotherapy in progress Liver, kidney, or hematologic diseases Immunosuppression Corticosteroid therapy in progress Pregnancy Inflammatory or autoimmune diseases of the oral cavity Poor oral hygiene and lack of motivation
Bone defects were randomly divided into two groups (Table 1): (1) group A (Ti-mesh group), treated with a three-dimensional (3D) bone reconstruction using bone chips taken from the mandibular symphysis and covered with a Ti mesh; or (2) group B (bone block group), treated with a 3D bone reconstruction through autologous cortical bone graft combined with particulate bone harvested from the same region.
Clinical measurements
Bone height and width were measured by periodontal probe (15 UNC/CP, Hu-Friedy) and recorded by the same operator approximating to 0.5 mm at baseline surgical procedure and at time of implant placement (reentry). Two horizontal measurements were taken, one at the point of greatest coronal convexity of the adjacent teeth and one at the greatest concavity of the defects. For the second measurement, the distance to the adjacent teeth’s cementoenamel junction (CEJ) was recorded to standardize the height measurement. Vertical measurements were taken at the maximum bone deficiency and compared to adjacent bone peaks. Table 2 shows the bone defect measurements.
Surgical procedures
Surgical procedures were performed under local anesthesia (mepivacaine
The International Journal of Periodontics & Restorative Dentistry © 2015 BY QUINTESSENCE PUBLISHING CO, INC. PRINTING OF THIS DOCUMENT IS RESTRICTED TO PERSONAL USE ONLY. NO PART MAY BE REPRODUCED OR TRANSMITTED IN ANY FORM WITHOUT WRITTEN PERMISSION FROM THE PUBLISHER.
e3
Table 2 Measurements (µm) of preoperative defects in the two study groups
Patient 1 2 3 4 5 Mean ± SD
(A) Titanium mesh group
(B) Cortical bone group
Horizontal coronal Deep horizontal Vertical bone bone defect bone defect defect
Horizontal coronal Deep horizontal Vertical bone bone defect bone defect defect
4 2 2 4 3
4 4 3 4 4 3.4 ± 0.8
2 2 1 1 2 1.6 ± 0.5
3 2 3 3 2
4 3 4 3 4 3.1 ± 0.7
2 2 1 1 2 1.6 ± 0.7
Fig 1 Bone defects and clinical measurement before the clinical procedure.
a
2% + epinephrine 1:100,000) plus oral sedation (midazolam 5 mg). The patients were premedicated 1 hour prior with amoxicillin plus clavulanic acid 2 g orally. They had been instructed to rinse with 0.20% chlorhexidine for 1 minute twice a day for 2 days before surgery. Surgical access was through a midcrestal incision, maximizing the keratinized tissue on each side of the incision, and through an intrasulcular buccal incision at the adjacent teeth. Fullthickness flaps were reflected to expose the alveolar ridge. A complete debridement of the fibrous tissue on the site was performed, and the defect was measured as previously described (Fig 1). The donor site was the mandibular symphysis in all cases (Fig 2b).
b
In group B, the bone graft was harvested from the chin using a microsaw for the block, which was then scraped to obtain the particulate. The residual bone cortex was fitted with two Ti synthesis screws, away from the recipient bed, in order to maintain the space and determine the shape and width of the alveolar crest. The remaining space between the recipient bed and bone block was then filled with the bone particulate (Fig 2a). For group A, the bone particulate was obtained directly from the symphysis through scraping, applied to the recipient site, covered with a Ti mesh appropriately cropped and shaped, and secured to vestibular native bone with two mini-Ti screws (Fig 2c).
The flap was carefully released and sutured with 5-0 Monomyd (Butterfly) without tension. Patients were instructed not to brush the surgical site and to continue rinsing with 0.20% chlorhexidine twice a day until suture removal 15 days later. Postoperative therapy included amoxicillin plus clavulanic acid 1 g twice a day for 6 days and ibuprofen 400 mg twice a day for the first 3 days. All patients had weekly checkups for the first month, biweekly checkups for the second month, and monthly checkups in the third and fourth months. Four months after bone grafting, implants were inserted. A fullthickness flap was reflected and, after removal of all fibrous tissue,
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e4
a
b
c
Fig 2 (a) Bone block graft (group A), (b) GBR with titanium mesh (group B), and (c) particulate autologous bone harvested from the chin.
Fig 3 Clinical aspect of bone increase.
a
b
the dimension of the alveolar ridge defect was measured (Fig 3). Bone volume measurements were taken and recorded as previously described for the baseline evaluation (Table 3). Before drilling the implant sites, bone specimens were obtained using a 2-mm biopsy trephine bur (Stoma, Storz am Mark), obtaining a core of tissue that intersected the augmented bone (Figs 4a and 5a). Ten NobelActive implants (Nobel Biocare; 3.0-mm diameter and 15-mm length) were inserted as prosthetically planned.
Immunohistochemistry
Histologic analyses were performed on bone samples derived from group A and group B. Each bone
sample was fixed in 10% buffered formalin, demineralized in nitric acid at 14% for 48 hours, dehydrated in an ascending series of alcohol (50%, 75%, 95%, and 100% for 24 hours), cleared in xylene for 24 hours, and embedded in paraffin. For immunohistochemistry and hematoxylin and eosin (HE) staining, 5-µm paraffin-embedded samples were sectioned. The sections were deparaffined and rehydrated with xylene and a decreasing scale of alcohols and then distilled water. Immunohistochemical analyses for vimentin and CD4 and CD8 lymphocytes were performed with the Dako EnVision + System-HRP kit (Dako Cytomation), according to the manufacturer’s instructions. The nuclei were stained with hematoxylin and the sections were observed under a light microscope.
Statistical analysis
To evaluate the differences between measurements before and after treatment and between the two groups, a Student t test was used for statistical evaluation. A value of P < .05 was considered significant.
Results Five patients were recruited (two men and three women), between 19 and 35 years old (mean: 25.4, SD: 5.94). Patient data and randomization of the defects are shown in Table 1. Baseline (preoperative) defects are summarized in Table 2, giving an overall horizontal defect of 3.4 mm (SD: 0.8) in the Ti mesh group and of 3.1 mm (SD: 0.7) in the bone block
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e5
Table 3 Measurements (mm) of residual defects at the time of the second surgery
Patient 1 2 3 4 5 Mean ± SD
a
(A) Titanium mesh group
(B) Cortical bone group
Horizontal coronal Deep horizontal Vertical bone bone defect bone defect defect
Horizontal coronal Deep horizontal Vertical bone bone defect bone defect defect
0 0 –1 0 0
0 1 0 0 1
1 0 0 0 0
0.1 ± 0.6
0 0 1 0 0
0.2 ± 0.4
b
1 0 0 0 1
1 0 0 0 0
0.3 ± 0.5
c
0.2 ± 0.4
d
Fig 4 (a) Biopsy specimen and (b) histologic evaluation on bone block graft side (magnification ×10). (c) Formation of new bone tissue; (d) osteoid tissue, vascularized, near the lamellar bone, was detectable (magnification ×40).
a
b
c
d
Fig 5 (a) Biopsy specimen and (b) histologic evaluation on GBR side with titanium mesh and particulate bone autologous graft (5b magnifiction ×10; 5c, 5d, 5e magnification ×40).
e
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e6
a
b
c
d
group. Vertical mean defect was 1.6 mm for both groups with a slight difference in SD. At reentry, measurements of residual defects at the time of the second surgery showed an overall reset of vertical and horizontal defects (Table 3). Statistical analyses revealed no differences between the two groups (t value = 1.70, P = .104). Only one patient reported a transient paresthesia in the chin area. For the remaining patients, healing was uncomplicated. In no case was there exposure of the Ti mesh or cortical bone graft.
Histologic analyses
HE staining revealed the formation of new bone tissue, richly vascularized with surrounding cells
peppered in close contact with the mature lamellar bone graft and the recipient bed in both groups (Figs 4b and 5b). The regenerated bone was characterized by cells, probably osteoblasts that form osteoid matrix, localized to the front of preexisting bone tissue. Moreover, osteocytes containing lacunae were visible. There were no significant differences between the two groups. Vimentin, CD4, and CD8 expressions also were analyzed. Vimentin is part of the so-called intermediate filaments, which, together with microtubules and actin microfilaments, constitute the cytoskeleton of eukaryotic cells. It is expressed by mesenchymal cells and is used as a tissues marker of mesenchymal origin. Positivity for vimentin was detectable for both groups tested without significant differences, indicating mesenchymal
Fig 6 (a, magnification ×40; b, magnification ×10) The immunohistochemical images for CD4 and CD8, respectively, show relative rarity of leuckocytes with predominant perivascular distribution. (c, magnification ×20; d, magnification ×40) Vimentin in immunohistochemistry. Barring very slight inflammatory activity immediately behind the particles of grafted tissue, there are no significant differences in the samples from the two study groups.
origin of neo-formed tissue (Fig 6). To investigate the presence of infiltrated lymphocytes and inflammation, CD4 and CD8 expressions were evaluated. The CD4 molecule belongs to the immunoglobulin (Ig) superfamily and is expressed on lymphocytes T helper, monocytes, and macrophages. The CD8 molecule also belongs to the Ig superfamily and is expressed on cytotoxic T lymphocytes (CTL). Immunohistochemical analyses for CD4 and CD8 showed a relative rarity of these cells with predominant perivascular distribution. No significant differences between the two study groups were detectable (see Fig 6). In conclusion, the immunohistochemical analyses showed that in both study groups an ongoing regenerative/reparative process was present, without significant differences between groups.
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e7 Fig 7 (a) The final result. (b to d) The biologic results in hard and soft tissue produce excellent esthetic architecture of the periimplant soft tissue and prosthetic crown.
a
b
Discussion According to this study, both of the bone augmentation techniques generated a sufficient amount of bone to insert an implant properly. At reentry, both bone block graft and augmented bone under Ti meshes appeared clinically well incorporated into the native bone, suggesting that good contact and good fit between the graft and the recipient site had been obtained during the first surgery. No exposure of the Ti mesh was observed in the current study. This phenomenon, which is rather commonly reported,18 was carefully
c
avoided by a complete release of the flaps during the first surgery. Moreover, several authors have described neurologic problems due to bone harvesting from the mandibular symphysis, characterized by paresthesia, anesthesia, and hyperalgesia of the chin area.23,24 In this study, only one patient reported paresthesia in the chin region, which spontaneously resolved within 8 weeks. The authors’ results, in accordance with Nkenke et al,23 were supported by the surgical technique at the donor site, which required a secure distance from tooth apexes and nerve emergences.
d
Histologic investigations confirmed excellent integration and revascularization of the graft, with formation of new bone tissue and no signs of relevant inflammatory processes in either study group. The evaluation of bone defects at baseline and at reentry was a daunting task because of the obvious difficulty in taking measurements. The authors opted for intraoperatory clinical measurements in order to compare the augmented site using a CBCT scan while a metal mesh was still inserted, since an intraoperatory CBCT scan taken after mesh removal was not possible in
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e8 the area where the surgery was performed. The authors did not create a surgical individual stent for measurements because all the defects were interdental and confined to a single tooth with many repeatable reference points. The clinical measurements provided similar results for both study groups, highlighting adequate bone gains and a similar bone resistance to drilling during site preparation.
Conclusions On the basis of the two techniques described, applied to this split mouth study, no relevant differences were found between the two groups. Although the application of the Timesh might be considered more effective in the modelling of the crest defect, this study found no relevant difference, bar longer operation time for the bone block surgery. Further studies are needed to increase the sample size, to verify augmentation stability over time, and to show the success of implant therapy in the medium and long term and eventual differences in the incidence of biologic or esthetic complications using the two techniques.
Acknowledgments The authors reported no conflicts of interest related to this study.
References 1. Widmark G, Andersson B, Ivanoff CJ. Mandibular bone graft in the anterior maxilla for single-tooth implants. Presentation of surgical method. Int J Oral Maxillofac Surg 1997;26:106–109. 2. Sjostrom M, Sennerby L, Nilson H, Lundgren S. Reconstruction of the atrophic edentulous maxilla with free iliac crest grafts and implants: A 3-year report of a prospective clinical study. Clin Implant Dent Relat Res 2007;9:46–59. 3. Donos N, Mardas N, Chadha V. Clinical outcomes of implants following lateral bone augmentation: Systematic assessment of available options (barrier membranes, bone grafts, split osteotomy). J Clin Periodontol 2008;35:173–202. 4. Hammerle CH, Jung RE, Yaman D, Lang NP. Ridge augmentation by applying bioresorbable membranes and deproteinized bovine bone mineral: A report of twelve consecutive cases. Clin Oral Implants Res 2008;19:19–25. 5. 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. 6. Gonzalez-Garcia R, Monje F, Moreno C. Alveolar split osteotomy for the treatment of the severe narrow ridge maxillary atrophy: A modified technique. Int J Oral Maxillofac Surg 2011;40:57–64. 7. Simion M, Baldoni M, Zaffe D. Jawbone enlargement using immediate implant placement associated with a split-crest technique and guided tissue regeneration. Int J Periodontics Restorative Dent 1992;12:462–473. 8. Scipioni A, Bruschi GB, Calesini G. The edentulous ridge expansion technique: A five-year study. Int J Periodontics Restorative Dent 1994;14:451–459. 9. Santagata M, Guariniello L, Tartaro G. A modified edentulous ridge expansion technique and immediate implant placement: A 3-year follow-up [epub ahead of print 2013 May 3]. J Oral Implantol. 10. Schwartz-Arad D, Levin L. Multi-tier technique for bone augmentation using intraoral autogenous bone blocks. Implant Dent 2007;16:5–12. 11. Levin L, Nitzan D, Schwartz-Arad D. Success of dental implants placed in intraoral block bone grafts. J Periodontol 2007;78:18–21.
12. Schwartz-Arad D, Levin L. Intraoral onlay bone grafts for implant site preparation. Pract Proced Aesthet Dent 2006;18 (suppl):10. 13. Schwartz-Arad D, Levin L, Sigal L. Surgical success of intraoral autogenous block onlay bone grafting for alveolar ridge augmentation. Implant Dent 2005; 14:131–138. 14. Schwartz-Arad D, Levin L. Intraoral autogenous block onlay bone grafting for extensive reconstruction of atrophic maxillary alveolar ridges. J Periodontol 2005; 76:636–641. 15. Boyne PJ. Restoration of osseous defects in maxillofacial casualities. J Am Dent Assoc 1969;78:767–776. 16. Boyne PJ, Cole MD, Stringer D, Shafqat JP. A technique for osseous restoration of deficient edentulous maxillary ridges. J Oral Maxillofac Surg 1985;43:87–91. 17. Gongloff RK, Cole M, Whitlow W, Boyne PJ. Titanium mesh and particulate cancellous bone and marrow grafts to augment the maxillary alveolar ridge. Int J Oral Maxillofac Surg 1986;15:263–268. 18. von Arx T, Hardt N, Wallkamm B. The TIME technique: A new method for localized alveolar ridge augmentation prior to placement of dental implants. Int J Oral Maxillofac Implants 1996;11:387–394. 19. de Freitas RM, Susin C, Spin-Neto R, et al. Horizontal ridge augmentation of the atrophic anterior maxilla using rhBMP-2/ ACS or autogenous bone grafts: A proofof-concept randomized clinical trial. J Clin Periodontol 2013;40:968–975. 20. Guze KA, Arguello E, Kim D, Nevins M, Karimbux NY. Growth factor-mediated vertical mandibular ridge augmentation: A case report. Int J Periodontics Restorative Dent 2013;33:611–617. 21. Misch CM. Bone augmentation of the atrophic posterior mandible for dental implants using rhBMP-2 and titanium mesh: Clinical technique and early results. Int J Periodontics Restorative Dent 2011; 31:581–589. 22. Smiler D, Soltan M, Lee JW. A histomorphogenic analysis of bone grafts augmented with adult stem cells. Implant Dent 2007;16:42–53. 23. Nkenke E, Schultze-Mosgau S, Radespiel-Tröger M, Kloss F, Neukam FW. Morbidity of harvesting of chin grafts: A prospective study. Clin Oral Implants Res 2001;12:495–502. 24. Raghoebar GM, Louwerse C, Kalk WW, Vissink A. Morbidity of chin bone harvesting. Clin Oral Implants Res 2001;12: 503–507.
The International Journal of Periodontics & Restorative Dentistry © 2015 BY QUINTESSENCE PUBLISHING CO, INC. PRINTING OF THIS DOCUMENT IS RESTRICTED TO PERSONAL USE ONLY. NO PART MAY BE REPRODUCED OR TRANSMITTED IN ANY FORM WITHOUT WRITTEN PERMISSION FROM THE PUBLISHER.
Block Versus Particulate/Titanium Mesh for Ridge Augmentation for Mandibular Lateral Incisor Defects: Clinical and Histologic Analysis Salvatore D’Amato, MD, DDS1 Gianpaolo Tartaro, MDS2 Angelo Itro, MD, DDS3 Livia Nastri, DDS, PhD4 Mario Santagata, MD, PhD5 The purpose of this study was to clinically, histologically, and immunohistochemically evaluate the quantity and quality of newly regenerated bone by means of direct clinical measuring and biopsy specimens of alveolar ridges augmented by autogenous cortical bone or titanium micromesh—both filled with autogenous particulate bone graft in the anterior jaws. For the preliminary study, 10 alveolar bone defects in five partially edentulous patients (two men and three women), between 19 and 35 years old (mean: 25.4, SD: 5.94) were selected. Bone defects were randomly (coin toss) divided into two groups: A (micromesh) and B (bone block). The donor site was the mandibular symphysis in all cases. On the return appointment, operative grafts appeared well incorporated into the native bone, which suggests that good contact and fit between the graft and the recipient site had been obtained during the first surgery. Histologic investigations confirmed excellent integration and revascularization of the graft in both study groups, with formation of new bone tissue without any relevant inflammation. (Int J Periodontics Restorative Dent 2015;35:e1–e8. doi: 10.11607/prd.2073)
Aggregate Professor Maxillofacial Surgery, Division of Oral and Maxillofacial Surgery, Multidisciplinary Department of Medical and Dental Specialties, AOU—Second University of Naples, Naples, Italy. 2Head of Maxillofacial Surgery, Division of Oral and Maxillofacial Surgery, Multidisciplinary Department of Medical and Dental Specialties, AOU—Second University of Naples, Naples, Italy. 3Director of Multidisciplinary Department of Medical and Dental Specialities, Division of Oral and Maxillofacial Surgery, Multidisciplinary Department of Medical and Dental Specialties, AOU—Second University of Naples, Naples, Italy. 4Aggregate Professor of Periodontology, Division of Oral and Maxillofacial Surgery, Multidisciplinary Department of Medical and Dental Specialties, AOU—Second University of Naples, Naples, Italy. 5Assistant Professor, Division of Oral and Maxillofacial Surgery, Multidisciplinary Department of Medical and Dental Specialties, AOU–Second University of Naples, Naples, Italy. 1
Correspondence to: Dr Salvatore D’Amato, B. Croce, 18 80059, Torre del Greco Napoli, Italy; email: [email protected]. ©2015 by Quintessence Publishing Co Inc.
The reconstruction of alveolar ridges for implant placement is still a challenging surgical procedure, especially in cases of extensive vertical and horizontal bone atrophy. A number of surgical procedures have been used to reconstruct the alveolar crest, including “split-ridge” (osteotomy for lateral expansion)1–4; osteodistraction; bone grafting with various grafting materials (autogenous bone, allograft, xenograft, and alloplastic materials); guided bone regeneration (GBR), alone or in combination with grafting materials1–9; and other techniques.10–14 One of the major challenges, however, is to minimize the resorption of grafted bone. Titanium (Ti) mesh was first introduced for the reconstruction of large osseous defects by Boyne15 and was later proposed for osseous restoration of deficient edentulous maxillary ridges.16,17 In 1996, von Arx et al18 introduced Ti micromesh for reconstructive implant surgery and reported positive results for a staged approach (ridge augmentation performed before implant placement) and a simultaneous procedure (implant placement and ridge
Volume 35, Number 1, 2015 © 2015 BY QUINTESSENCE PUBLISHING CO, INC. PRINTING OF THIS DOCUMENT IS RESTRICTED TO PERSONAL USE ONLY. NO PART MAY BE REPRODUCED OR TRANSMITTED IN ANY FORM WITHOUT WRITTEN PERMISSION FROM THE PUBLISHER.
e2 Randomization
Table 1 Patient distribution Patient 1 2 3 4 5
Age (y)
Sex
Titanium mesh
Cortical bone
19 23 26 24 35
F F M M F
Right side Right side Left side Left side Left side
Left side Left side Right side Right side Right side
augmentation performed at the same time). Recent clinical studies have confirmed the reliability of this technique.19–21 Few reports in the literature address histologic evidence in humans of the results obtained by using Ti mesh for localized alveolar ridge augmentation.22 Therefore, the purpose of this study was to clinically, histologically, and immunohistochemically evaluate the quantity and quality of newly regenerated bone for mandibular lateral incisor defects employing and comparing two different techniques: autogenous cortical bone graft versus Ti micromesh, both filled with autogenous particulate bone.
performed at baseline, including a study cast, periapical or panoramic radiographs, and cone beam computed tomography (CBCT) scan. The main inclusion criterion was the presence of a bilateral agenesis of the mandibular lateral incisors with a horizontal bone defect of at least 3 mm (CBCT scan) insufficient for correct prosthetic implant positioning. In addition, patients had to agree to participate in a postoperative follow-up program and to sign an informed consent form. The exclusion criteria were as follows: • • •
Method and materials • Selection of patients
Ten alveolar bone defects related to a missing mandibular lateral incisor were selected in five partially edentulous patients from those referred to Second University of Naples, Multidisciplinary Department of Medical-Surgical and Dental Specialties. After a medical history interview and clinical examination, all patients received a prophylaxis session. A preoperative evaluation was
• • • • • • •
Local infection Smoking (more than 10 cigarettes per day) Uncontrolled diabetes (HbA1c > 53 mmol/mol) Previous radiotherapy in head and neck region Chemotherapy in progress Liver, kidney, or hematologic diseases Immunosuppression Corticosteroid therapy in progress Pregnancy Inflammatory or autoimmune diseases of the oral cavity Poor oral hygiene and lack of motivation
Bone defects were randomly divided into two groups (Table 1): (1) group A (Ti-mesh group), treated with a three-dimensional (3D) bone reconstruction using bone chips taken from the mandibular symphysis and covered with a Ti mesh; or (2) group B (bone block group), treated with a 3D bone reconstruction through autologous cortical bone graft combined with particulate bone harvested from the same region.
Clinical measurements
Bone height and width were measured by periodontal probe (15 UNC/CP, Hu-Friedy) and recorded by the same operator approximating to 0.5 mm at baseline surgical procedure and at time of implant placement (reentry). Two horizontal measurements were taken, one at the point of greatest coronal convexity of the adjacent teeth and one at the greatest concavity of the defects. For the second measurement, the distance to the adjacent teeth’s cementoenamel junction (CEJ) was recorded to standardize the height measurement. Vertical measurements were taken at the maximum bone deficiency and compared to adjacent bone peaks. Table 2 shows the bone defect measurements.
Surgical procedures
Surgical procedures were performed under local anesthesia (mepivacaine
The International Journal of Periodontics & Restorative Dentistry © 2015 BY QUINTESSENCE PUBLISHING CO, INC. PRINTING OF THIS DOCUMENT IS RESTRICTED TO PERSONAL USE ONLY. NO PART MAY BE REPRODUCED OR TRANSMITTED IN ANY FORM WITHOUT WRITTEN PERMISSION FROM THE PUBLISHER.
e3
Table 2 Measurements (µm) of preoperative defects in the two study groups
Patient 1 2 3 4 5 Mean ± SD
(A) Titanium mesh group
(B) Cortical bone group
Horizontal coronal Deep horizontal Vertical bone bone defect bone defect defect
Horizontal coronal Deep horizontal Vertical bone bone defect bone defect defect
4 2 2 4 3
4 4 3 4 4 3.4 ± 0.8
2 2 1 1 2 1.6 ± 0.5
3 2 3 3 2
4 3 4 3 4 3.1 ± 0.7
2 2 1 1 2 1.6 ± 0.7
Fig 1 Bone defects and clinical measurement before the clinical procedure.
a
2% + epinephrine 1:100,000) plus oral sedation (midazolam 5 mg). The patients were premedicated 1 hour prior with amoxicillin plus clavulanic acid 2 g orally. They had been instructed to rinse with 0.20% chlorhexidine for 1 minute twice a day for 2 days before surgery. Surgical access was through a midcrestal incision, maximizing the keratinized tissue on each side of the incision, and through an intrasulcular buccal incision at the adjacent teeth. Fullthickness flaps were reflected to expose the alveolar ridge. A complete debridement of the fibrous tissue on the site was performed, and the defect was measured as previously described (Fig 1). The donor site was the mandibular symphysis in all cases (Fig 2b).
b
In group B, the bone graft was harvested from the chin using a microsaw for the block, which was then scraped to obtain the particulate. The residual bone cortex was fitted with two Ti synthesis screws, away from the recipient bed, in order to maintain the space and determine the shape and width of the alveolar crest. The remaining space between the recipient bed and bone block was then filled with the bone particulate (Fig 2a). For group A, the bone particulate was obtained directly from the symphysis through scraping, applied to the recipient site, covered with a Ti mesh appropriately cropped and shaped, and secured to vestibular native bone with two mini-Ti screws (Fig 2c).
The flap was carefully released and sutured with 5-0 Monomyd (Butterfly) without tension. Patients were instructed not to brush the surgical site and to continue rinsing with 0.20% chlorhexidine twice a day until suture removal 15 days later. Postoperative therapy included amoxicillin plus clavulanic acid 1 g twice a day for 6 days and ibuprofen 400 mg twice a day for the first 3 days. All patients had weekly checkups for the first month, biweekly checkups for the second month, and monthly checkups in the third and fourth months. Four months after bone grafting, implants were inserted. A fullthickness flap was reflected and, after removal of all fibrous tissue,
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a
b
c
Fig 2 (a) Bone block graft (group A), (b) GBR with titanium mesh (group B), and (c) particulate autologous bone harvested from the chin.
Fig 3 Clinical aspect of bone increase.
a
b
the dimension of the alveolar ridge defect was measured (Fig 3). Bone volume measurements were taken and recorded as previously described for the baseline evaluation (Table 3). Before drilling the implant sites, bone specimens were obtained using a 2-mm biopsy trephine bur (Stoma, Storz am Mark), obtaining a core of tissue that intersected the augmented bone (Figs 4a and 5a). Ten NobelActive implants (Nobel Biocare; 3.0-mm diameter and 15-mm length) were inserted as prosthetically planned.
Immunohistochemistry
Histologic analyses were performed on bone samples derived from group A and group B. Each bone
sample was fixed in 10% buffered formalin, demineralized in nitric acid at 14% for 48 hours, dehydrated in an ascending series of alcohol (50%, 75%, 95%, and 100% for 24 hours), cleared in xylene for 24 hours, and embedded in paraffin. For immunohistochemistry and hematoxylin and eosin (HE) staining, 5-µm paraffin-embedded samples were sectioned. The sections were deparaffined and rehydrated with xylene and a decreasing scale of alcohols and then distilled water. Immunohistochemical analyses for vimentin and CD4 and CD8 lymphocytes were performed with the Dako EnVision + System-HRP kit (Dako Cytomation), according to the manufacturer’s instructions. The nuclei were stained with hematoxylin and the sections were observed under a light microscope.
Statistical analysis
To evaluate the differences between measurements before and after treatment and between the two groups, a Student t test was used for statistical evaluation. A value of P < .05 was considered significant.
Results Five patients were recruited (two men and three women), between 19 and 35 years old (mean: 25.4, SD: 5.94). Patient data and randomization of the defects are shown in Table 1. Baseline (preoperative) defects are summarized in Table 2, giving an overall horizontal defect of 3.4 mm (SD: 0.8) in the Ti mesh group and of 3.1 mm (SD: 0.7) in the bone block
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e5
Table 3 Measurements (mm) of residual defects at the time of the second surgery
Patient 1 2 3 4 5 Mean ± SD
a
(A) Titanium mesh group
(B) Cortical bone group
Horizontal coronal Deep horizontal Vertical bone bone defect bone defect defect
Horizontal coronal Deep horizontal Vertical bone bone defect bone defect defect
0 0 –1 0 0
0 1 0 0 1
1 0 0 0 0
0.1 ± 0.6
0 0 1 0 0
0.2 ± 0.4
b
1 0 0 0 1
1 0 0 0 0
0.3 ± 0.5
c
0.2 ± 0.4
d
Fig 4 (a) Biopsy specimen and (b) histologic evaluation on bone block graft side (magnification ×10). (c) Formation of new bone tissue; (d) osteoid tissue, vascularized, near the lamellar bone, was detectable (magnification ×40).
a
b
c
d
Fig 5 (a) Biopsy specimen and (b) histologic evaluation on GBR side with titanium mesh and particulate bone autologous graft (5b magnifiction ×10; 5c, 5d, 5e magnification ×40).
e
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a
b
c
d
group. Vertical mean defect was 1.6 mm for both groups with a slight difference in SD. At reentry, measurements of residual defects at the time of the second surgery showed an overall reset of vertical and horizontal defects (Table 3). Statistical analyses revealed no differences between the two groups (t value = 1.70, P = .104). Only one patient reported a transient paresthesia in the chin area. For the remaining patients, healing was uncomplicated. In no case was there exposure of the Ti mesh or cortical bone graft.
Histologic analyses
HE staining revealed the formation of new bone tissue, richly vascularized with surrounding cells
peppered in close contact with the mature lamellar bone graft and the recipient bed in both groups (Figs 4b and 5b). The regenerated bone was characterized by cells, probably osteoblasts that form osteoid matrix, localized to the front of preexisting bone tissue. Moreover, osteocytes containing lacunae were visible. There were no significant differences between the two groups. Vimentin, CD4, and CD8 expressions also were analyzed. Vimentin is part of the so-called intermediate filaments, which, together with microtubules and actin microfilaments, constitute the cytoskeleton of eukaryotic cells. It is expressed by mesenchymal cells and is used as a tissues marker of mesenchymal origin. Positivity for vimentin was detectable for both groups tested without significant differences, indicating mesenchymal
Fig 6 (a, magnification ×40; b, magnification ×10) The immunohistochemical images for CD4 and CD8, respectively, show relative rarity of leuckocytes with predominant perivascular distribution. (c, magnification ×20; d, magnification ×40) Vimentin in immunohistochemistry. Barring very slight inflammatory activity immediately behind the particles of grafted tissue, there are no significant differences in the samples from the two study groups.
origin of neo-formed tissue (Fig 6). To investigate the presence of infiltrated lymphocytes and inflammation, CD4 and CD8 expressions were evaluated. The CD4 molecule belongs to the immunoglobulin (Ig) superfamily and is expressed on lymphocytes T helper, monocytes, and macrophages. The CD8 molecule also belongs to the Ig superfamily and is expressed on cytotoxic T lymphocytes (CTL). Immunohistochemical analyses for CD4 and CD8 showed a relative rarity of these cells with predominant perivascular distribution. No significant differences between the two study groups were detectable (see Fig 6). In conclusion, the immunohistochemical analyses showed that in both study groups an ongoing regenerative/reparative process was present, without significant differences between groups.
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e7 Fig 7 (a) The final result. (b to d) The biologic results in hard and soft tissue produce excellent esthetic architecture of the periimplant soft tissue and prosthetic crown.
a
b
Discussion According to this study, both of the bone augmentation techniques generated a sufficient amount of bone to insert an implant properly. At reentry, both bone block graft and augmented bone under Ti meshes appeared clinically well incorporated into the native bone, suggesting that good contact and good fit between the graft and the recipient site had been obtained during the first surgery. No exposure of the Ti mesh was observed in the current study. This phenomenon, which is rather commonly reported,18 was carefully
c
avoided by a complete release of the flaps during the first surgery. Moreover, several authors have described neurologic problems due to bone harvesting from the mandibular symphysis, characterized by paresthesia, anesthesia, and hyperalgesia of the chin area.23,24 In this study, only one patient reported paresthesia in the chin region, which spontaneously resolved within 8 weeks. The authors’ results, in accordance with Nkenke et al,23 were supported by the surgical technique at the donor site, which required a secure distance from tooth apexes and nerve emergences.
d
Histologic investigations confirmed excellent integration and revascularization of the graft, with formation of new bone tissue and no signs of relevant inflammatory processes in either study group. The evaluation of bone defects at baseline and at reentry was a daunting task because of the obvious difficulty in taking measurements. The authors opted for intraoperatory clinical measurements in order to compare the augmented site using a CBCT scan while a metal mesh was still inserted, since an intraoperatory CBCT scan taken after mesh removal was not possible in
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e8 the area where the surgery was performed. The authors did not create a surgical individual stent for measurements because all the defects were interdental and confined to a single tooth with many repeatable reference points. The clinical measurements provided similar results for both study groups, highlighting adequate bone gains and a similar bone resistance to drilling during site preparation.
Conclusions On the basis of the two techniques described, applied to this split mouth study, no relevant differences were found between the two groups. Although the application of the Timesh might be considered more effective in the modelling of the crest defect, this study found no relevant difference, bar longer operation time for the bone block surgery. Further studies are needed to increase the sample size, to verify augmentation stability over time, and to show the success of implant therapy in the medium and long term and eventual differences in the incidence of biologic or esthetic complications using the two techniques.
Acknowledgments The authors reported no conflicts of interest related to this study.
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