Massimo Simion

Publications of Massimo Simion

• Treatment of combined endodontic-periodontic lesions using guided tissue regeneration: clinical case and histology.

  Authors: Carlo Ghezzi, Mauro Virzi, Peter Schupbach, Alessandro Broccaioli, Massimo Simion

  The International journal of periodontics & restorative dentistry. 08/2012; 32(4):433-9.

  The aim of this case report is to histologically evaluate periapical healing after combined endodontic-periodontic treatment. A maxillary left central incisor was treated with conventional endodonticThe aim of this case report is to histologically evaluate periapical healing after combined endodontic-periodontic treatment. A maxillary left central incisor was treated with conventional endodontic therapy, followed by periodontal surgery. The facial bony defect was filled with a mixture of autologous bone and Bio-Oss. A resorbable membrane was used. Histology showed the presence of new cementum, ligament, and bone around the apex of the treated tooth. This finding was clinically associated with minimal residual probing depth and maximum attachment gain. This histologic report demonstrates the possibility of true regeneration in a case of severe periodontal attachment loss resulting from an endodontic-periodontic lesion.

• Evaluation of a Resorbable Collagen Matrix Infused with rhPDGF-BB in Peri-implant Soft Tissue Augmentation: A Preliminary Report with 3.5 Years of Observation.

  Authors: Massimo Simion, Isabella Rocchietta, Filippo Fontana, Claudia Dellavia

  The International journal of periodontics & restorative dentistry. 06/2012; 32(3):273-82.

  Soft tissue augmentation around dental implants in the esthetic region remains a challenging and unpredictable procedure. The ideal surgical technique would include of an off-the-shelf product toSoft tissue augmentation around dental implants in the esthetic region remains a challenging and unpredictable procedure. The ideal surgical technique would include of an off-the-shelf product to minimize morbidity after autogenous grafting procedures. The aim of this study was to use a resorbable collagen matrix (Mucograft) to serve as a scaffold to recombinant human platelet-derived growth factor BB (rhPDGF-BB) to increase peri-implant soft tissue volume in anterior maxillary sites. A total of six patients who had previously undergone a bone regeneration procedure were included in this study. The collagen matrix was applied during stage-two surgery (expanded polytetrafluoroethylene membrane removal and implant placement). Measurements were performed through customized stents by means of endodontic files, and at abutment connection, a soft tissue biopsy specimen was harvested for histologic examination. The healing period was uneventful in all six patients. Measurements were taken apically, centrally, and occlusally for each site. The mean gains in volume from baseline to the 4-month measurement at the apical, central, and occlusal aspects were 0.87 ± 2.13 mm, 2.14 ± 3.27 mm, and 0.35 ± 3.20 mm, respectively. The results showed a moderate increase in the soft tissue volume in esthetic peri-implant sites when applying a collagen matrix infused with rhPDGF-BB. However, the measuring techniques available need to be further improved to record exact changes in the soft tissue volume.

• Soft tissue integration of a porcine collagen membrane: an experimental study in pigs.

  Authors: Isabella Rocchietta, Peter Schupbach, Carlo Ghezzi, Emilio Maschera, Massimo Simion

  The International journal of periodontics & restorative dentistry. 02/2012; 32(1):e34-40.

  Autogenous soft tissue augmentation procedures around natural teeth and dental implants are performed daily by clinicians. However, patient morbidity is often associated with the second surgicalAutogenous soft tissue augmentation procedures around natural teeth and dental implants are performed daily by clinicians. However, patient morbidity is often associated with the second surgical site; hence, research is moving toward an era where matrices may substitute autogenous grafts. The aim of this study was to assess the soft tissue response to a collagen matrix in an animal model. Nine pigs were included in this study. Each animal received four collagen matrices, two for each mandible. Three cohorts were included in the study: group A, where the matrix was applied as an onlay on a partial-thickness flap; group B, where the matrix was inserted under a partial-thickness flap; and group C, where the matrix was inserted in an inverted position under a full-thickness flap. Sacrifice occurred at 7, 15, and 30 days postoperatively for histologic assessment. The collagen matrix was seen in place for the first 2 weeks, and it was completely replaced by healthy connective tissue within 30 days in the inlay cohorts. No inflammatory adverse reactions were noticed in any specimen, resulting in optimal integration of the device. This study showed an optimal integration within 30 days postoperative of the placement of experimental collagen matrix in the soft tissues of an animal model. Its proven safety in this model provides an optimal starting point for further research projects considering its clinical applications.

• Vertical Ridge Augmentation Using an Equine Bone and Collagen Block Infused With Recombinant Human Platelet Derived Growth Factor-BB (rhPDGF-BB): A Randomized Single-Blind Histologic Study in Non-Human Primates.

  Authors: Massimo Simion, Myron Nevins, Khalid Al-Hezaimi, Emilio Maschera, Filippo Fontana, Isabella Rocchietta, Peter Schupbach, Nadeem Karimbux, David M Kim

  Journal of periodontology. 01/2012;

  Background: This study tested the effectiveness of hydroxyapatite and collagen bone blocks of equine origin (eHAC), infused with recombinant platelet derived growth factor-BB (rhPDGF-BB), to augmentBackground: This study tested the effectiveness of hydroxyapatite and collagen bone blocks of equine origin (eHAC), infused with recombinant platelet derived growth factor-BB (rhPDGF-BB), to augment localized posterior mandibular defects in non-human primates (Papio hamadryas). Methods: Bilateral critical-size defects simulating severe atrophy were created at the time of the posterior teeth removal. Test and control blocks (without growth factor) were randomly grafted into the respective sites in each non-human primates. Results: All sites exhibited vertical ridge augmentation, with physiological hard and soft tissue integration of the blocks when clinical and histological examinations were done at four months after the vertical ridge augmentation procedure. There was a clear, though non-significant, tendency to increased regeneration in the test sites. As in the first two preclinical studies in this series using canines, experimental eHAC blocks infused with rhPDGF-BB proved to be a predictable and technically viable method to predictably regenerate bone and soft tissue in-critical size defects. Conclusion: This investigation supplies further evidence that eHAC blocks infused with rhPDGF-BB growth factor is a predictable and technically feasible option for vertical augmentation of severely resorbed ridges.

• Effects of a calcium phosphate coating on the osseointegration of endosseous implants in a rabbit model.

  Authors: Filippo Fontana, Isabella Rocchietta, Alessandro Addis, Peter Schupbach, Gianfranco Zanotti, Massimo Simion

  Clinical oral implants research. 12/2010; 22(7):760-6.

  The aim of the present study was to evaluate a Ca-P coated implant surface in a rabbit model. The Ca-P surface (test) was compared to the titanium porous oxide surface (control) in terms ofThe aim of the present study was to evaluate a Ca-P coated implant surface in a rabbit model. The Ca-P surface (test) was compared to the titanium porous oxide surface (control) in terms of bone-to-implant contact (BIC) and removal torque value. Two hundred and sixteen dental implants were inserted in the tibia and in the femur of 36 rabbits. One hundred and eight were represented by Ca-P oxidized surface implant and other 108 were titanium porous oxide surface modified implants. Each rabbit received six implants. Animals were sacrificed after 2, 4 and 9 weeks of healing. Each group included 12 rabbits. The femoral implant and the proximal implant of the tibia of each animal were subjected to the histologic analysis and the distal implants of the tibia underwent removal torque test (RTQ). Histological analysis in terms of BIC and RTQ did not revealed any significant difference between the Ca-P oxidized surface and the oxidized surface at 2 and 4 weeks. At 9 weeks, the oxidized surface demonstrated better results in terms of RTQ in the tibia. In conclusion, findings from the present study suggested that the Ca-P coating had no beneficial effect in improving bonding strength at the bone-implant interface either at 2, 4 and 9 weeks.

• Surface-modified zirconia implants: tissue response in rabbits.

  Authors: Isabella Rocchietta, Filippo Fontana, Alessandro Addis, Peter Schupbach, Massimo Simion

  Clinical oral implants research. 09/2009; 20(8):844-50.

  AIM: To evaluate the bone tissue response to zirconia implants with three different surface modifications in comparison with the oxidized titanium surface with the goal to optimize osseointegrationAIM: To evaluate the bone tissue response to zirconia implants with three different surface modifications in comparison with the oxidized titanium surface with the goal to optimize osseointegration in terms of strength and speed. MATERIALS AND METHODS: A total of 18 rabbits with 143 implants were used. One hundred and twenty-three were threaded zirconia ceramic implants with three different surface topographies and 20 modified titanium oxide implants were controls. Each rabbit received eight implants and sacrificed after 3 weeks. The removal torque test (RTQ) and histology were performed. RESULTS: Sixteen out of 18 rabbits completed the study with a total of 110 implants. No statistical significance was observed between the chemical modification implants compared with the topographically modified zirconia implant in terms of interfacial shear strength proven by the RTQ applied. No statistical significance was also observed in the bone-to-implant contact between the zirconia implants and the control oxidized implants. CONCLUSIONS: The findings suggest that additional specific chemical modifications of the topographically modified zirconia implants do not seem to enhance the bone-to-implant contact and appear not to increase the interfacial shear strength.

• Vertical ridge augmentation using an equine block infused with recombinant human platelet-derived growth factor-BB: a histologic study in a canine model.

  Authors: Massimo Simion, Myron Nevins, Isabella Rocchietta, Filippo Fontana, Emilio Maschera, Peter Schupbach, David M Kim

  The International journal of periodontics & restorative dentistry. 07/2009; 29(3):245-55.

  This preclinical study evaluated the efficacy of purified recombinant human platelet-derived growth factor (rhPDGF-BB), combined with a novel equine hydroxyapatite and collagen (eHAC) bone block, inThis preclinical study evaluated the efficacy of purified recombinant human platelet-derived growth factor (rhPDGF-BB), combined with a novel equine hydroxyapatite and collagen (eHAC) bone block, in providing vertical bone regeneration in critical-size defects simulating localized mandibular alveolar bone atrophy. In addition, the impact of barrier membrane placement in growth factor-mediated bone regeneration was also studied. Bilateral posterior mandibular defects simulating severe localized bony atrophy were created in 12 adult foxhounds following removal of all four mandibular premolars. Three months later, the defects were grafted as follows: group A: eHAC block alone; group B: eHAC block + collagen membrane; group C: eHAC block + rhPDGF-BB; group D: eHAC block + rhPDGF-BB + membrane. The animals were sacrificed after 5 months and the grafted areas were examined histologically, radiographically, and clinically. Groups A and B (controls) exhibited little to no vertical bone regeneration. Group C demonstrated significant vertical bone regeneration, with dense, well-vascularized bone, high bone-to-implant contact, and accelerated replacement of graft particles with newly formed bone. In group D, with the imposition of a barrier membrane, robust bone regeneration was less evident when compared to group C. As in the first study in this series, the importance of the periosteum as a source of osteoprogenitor cells in growth factor-mediated regenerative procedures is examined.

• Biocompatibility and manageability of a new fixable bone graft for the treatment of localized bone defects: preliminary study in a dog model.

  Authors: Filippo Fontana, Isabella Rocchietta, Claudia Dellavia, Myron Nevins, Massimo Simion

  The International journal of periodontics & restorative dentistry. 01/2009; 28(6):601-7.

  The present investigation was performed to compare the biocompatibility, safety, and manageability of a newly developed bone block and a deproteinized bovine bone block (Bio-Oss) for the treatment ofThe present investigation was performed to compare the biocompatibility, safety, and manageability of a newly developed bone block and a deproteinized bovine bone block (Bio-Oss) for the treatment of localized bone defects in a dog model. Two male beagle dogs were used for this study. The mandibular premolars were extracted and two saddle-type defects were created bilaterally in the edentulous area. The defects were filled according to a randomized design with Bio-Oss bone block or with an equine hydroxyapatite plus collagen bone block (eHAC). Most control and test sites developed dehiscences during healing. After 4 weeks, the animals were euthanized and each hemimandible was prepared for histologic examination. No significant difference in terms of local tolerance was observed between test and control sites, and test and control sites showed similar histologic findings. However, a significant difference was noticed between the Bio-Oss block and the new bone block in terms of manageability.

• Clinical outcomes of vertical bone augmentation to enable dental implant placement: a systematic review.

  Authors: Isabella Rocchietta, Filippo Fontana, Massimo Simion

  Journal of clinical periodontology. 10/2008; 35(8 Suppl):203-15.

  BACKGROUND: This review addressed the focused question of what is the predictability of vertical ridge augmentation techniques for patients, who were diagnosed with insufficient alveolar bone volumeBACKGROUND: This review addressed the focused question of what is the predictability of vertical ridge augmentation techniques for patients, who were diagnosed with insufficient alveolar bone volume for the placement of dental implants. MATERIAL AND METHODS: A systematic online review of three main databases was performed between 1966 and 1 November 2007. Four groups of vertical bone augmentation techniques have been identified and evaluated: (1) guided bone regeneration, (2) distraction osteogenesis, (3) onlay bone grafting, and (4) an array of different techniques. Data extraction was based on the following outcomes: (a) success and failure rate of the procedure (vertical bone gain/loss), (b) complication rate of the procedure, and (c) implant survival, success and failure rate. RESULTS: The initial search identified 189 papers from the electronic database. The review produced seven papers for GBR, 13 reporting distraction osteogenesis, five for onlay bone grafting and three describing different techniques. CONCLUSIONS: For the concept of vertical ridge augmentation to enable dental implant placement, there are clinical and histological data supporting its potential use. Given the confined number of investigators using these techniques and the low number of patient treatments reported in the literature, the generalizability of this approach is limited at this time.

• Three-dimensional alveolar bone reconstruction with a combination of recombinant human platelet-derived growth factor BB and guided bone regeneration: a case report.

  Authors: Massimo Simion, Isabella Rocchietta, Maurizio Monforte, Emilio Maschera

  The International journal of periodontics & restorative dentistry. 07/2008; 28(3):239-43.

  A report of a patient who presented with severe disfigurement of the maxillary left lateral incisor and canine area following oncologic surgery is presented. The bone defect extended 20 mm from theA report of a patient who presented with severe disfigurement of the maxillary left lateral incisor and canine area following oncologic surgery is presented. The bone defect extended 20 mm from the cervical line of adjacent teeth up to and including the nasal cavity. Treatment was performed with a 1:1 ratio of autogenous bone graft (harvested from the retromolar region) and deproteinized bovine bone particles. The composite graft was hydrolyzed with recombinant human platelet-derived growth factor BB and covered with a titanium-reinforced nonresorbable membrane. Second-stage surgery was performed at 6 months, at which point the membrane was removed and two titanium dental implants were successfully placed. The elapsed time from initial surgery to definitive prosthesis placement was 14 months.

• Bone regenerated via rhPDGF-bB and a deproteinized bovine bone matrix: backscattered electron microscopic element analysis.

  Authors: Isabella Rocchietta, Claudia Dellavia, Myron Nevins, Massimo Simion

  The International journal of periodontics & restorative dentistry. 01/2008; 27(6):539-45.

  This study used backscattered electron microscopy (BSE-SEM) to analyze specimens in which bone was augmented both horizontally and vertically with a xenograft scaffold and recombinant humanThis study used backscattered electron microscopy (BSE-SEM) to analyze specimens in which bone was augmented both horizontally and vertically with a xenograft scaffold and recombinant human platelet-derived growth factor (rhPDGF-BB), with or without a resorbable collagen membrane. The study objective was to compare percentage weight and volume calcium-phosphorus ratios of regenerated bone and native bone and the nature of the bony contact with two different implant surfaces. Examination of the nature of the mineralized tissues by BSE-SEM provides an understanding of the composition and element ratio of bone regenerated from nonautogenous grafts. The data collected demonstrated no statistically significant difference between regenerated bone and native bone in the two tested groups. Our observations suggest that bone regenerated via nonautogenous grafts displays composition, structure, and physical properties very similar to those of native bone. Similarly, no significant differences were observed at the bone-implant interface between bone regenerated proximal to oxidized versus machined implants.

• The safety and acceptability of an electric toothbrush on peri-implant mucosa in patients with oral implants in aesthetic areas: a prospective cohort study.

  Authors: Giulio Rasperini, Gaia Pellegrini, Antonia Cortella, Isabella Rocchietta, Dario Consonni, Massimo Simion

  European journal of oral implantology. 01/2008; 1(3):221-8.

  The aim of this cohort study was to evaluate the safety and the acceptability of an electric toothbrush used on the peri-implant mucosa of implants placed in the aesthetic area. One hundredThe aim of this cohort study was to evaluate the safety and the acceptability of an electric toothbrush used on the peri-implant mucosa of implants placed in the aesthetic area. One hundred consecutive patients rehabilitated with implants positioned in the maxillary aesthetic area were recruited. Implants had to be restored at least 6 months prior to baseline. At baseline, subjects were provided with Oral-B Professional Care 7000 and received appropriate instructions to brush twice a day over a 12-month period. Papillary bleeding index, recession and probing depth were measured at baseline and at 3, 6, and 12 months. Ninety-eight (98) patients completed the study. There was an overall reduction of recession (mean 0.2 mm) of borderline statistical significance. All of the changes occurred at the first followup visit (P=0.09) and persisted thereafter. The statistical analyses regarding the probing depth found a highly significant decrease over time (mean 0.3 mm). The bleeding score showed a gradual decrease over time, with a reduction at 12 months by more than half (0.65) in comparison with the baseline (1.50) and was shown to be highly significant (Wilcoxon sign-rank test: P < 0.001). No patient showed adverse effects such as ulcerations or desquamation. A high score of satisfaction by the patients using the electric toothbrush was reported (94% would continue to use it). The electric toothbrush Oral B Professional Care 7000 appears to be safe for patients with fixed prosthesis on implants in aesthetic areas. Successive randomised clinical trials are needed to compare this instrument with other therapeutic devices for mechanical plaque control.

• Vertical ridge augmentation by expanded-polytetrafluoroethylene membrane and a combination of intraoral autogenous bone graft and deproteinized anorganic bovine bone (Bio Oss).

  Authors: Massimo Simion, Filippo Fontana, Giulio Rasperini, Carlo Maiorana

  Clinical oral implants research. 11/2007; 18(5):620-9.

  OBJECTIVE: To evaluate, from a histological and histomorphometrical perspective, the efficacy of a 1 : 1 mixture of deproteinized bovine bone mineral (DBBM) and autogenous bone graft associated withOBJECTIVE: To evaluate, from a histological and histomorphometrical perspective, the efficacy of a 1 : 1 mixture of deproteinized bovine bone mineral (DBBM) and autogenous bone graft associated with an expanded-polytetrafluoroethylene (e-PTFE) membrane for vertical ridge augmentation in the human. MATERIAL AND METHODS: Seven patients with 10 surgical sites requiring vertical ridge augmentation of partially edentulous lower jaws were included in the study. The vertical augmentation procedure was performed combining a titanium-reinforced e-PTFE Gore-Tex membrane with a composite graft consisting of a 1 : 1 ratio of DBBM (Bio-Oss) and autogenous bone. Twenty-seven Branemark implants have been inserted. Eleven biopsies from the regenerated area were analyzed histologically and histomorphometrically. RESULTS: The healing period was uneventful in nine surgical sites. In one site the membrane showed an exposure after 3 months. At the abutment connection, all implants appeared stable and submerged by a hard regenerated tissue clinically similar to bone. The histological analysis showed new bone formation and ongoing remodelling of the autogenous bone and the DBBM particles. CONCLUSIONS: The findings from the present clinical and histological study support the use of a 1 : 1 combination of DBBM and autogenous bone chips for vertical ridge augmentation by means of guided bone regeneration techniques. The regenerated bone may lead to proper osseointegration of a dental implant inserted at the time of the regenerative procedure or after a healing period of at least 6 months. DBBM undergoes very slow resorption and substitution with new bone. Furthermore, long-term clinical studies are needed to confirm the positive effect of DBBM in enhancing the lasting stability of the vertically augmented bone.

• Three-dimensional ridge augmentation with xenograft and recombinant human platelet-derived growth factor-BB in humans: report of two cases.

  Authors: Massimo Simion, Isabella Rocchietta, Claudia Dellavia

  The International journal of periodontics & restorative dentistry. 05/2007; 27(2):109-15.

  The present paper reports on two patients who underwent three-dimensional ridge augmentation using a xenograft in combination with recombinant human platelet-derived growth factor-BB (rhPDGF-BB).The present paper reports on two patients who underwent three-dimensional ridge augmentation using a xenograft in combination with recombinant human platelet-derived growth factor-BB (rhPDGF-BB). Patient 1 received a deproteinized bovine block infused with PDGF and secured to the alveolar crest by two fixation screws to augment the crest horizontally. After 5 months, implants were successfully placed. Patient 2 underwent a vertical ridge augmentation procedure that combined deproteinized bovine bone particles embedded in a collagen matrix soaked in PDGF Three titanium dental implants were placed in each patient 5 months later. Clinical and histologic results showed excellent soft and hard tissue healing. Bone had regenerated throughout the whole area and the xenograft particles were embedded in bone, which presented resorption lacunae close to areas with ongoing bone formation. This indicated that, in augmented areas, intense physiologic remodeling was ongoing. No data exist concerning three-dimensional bone augmentation using PDGF and a xenograft in humans. This report suggests that the use of rhPDGF-BB in combination with a deproteinized bovine graft may have the potential to regenerate large three-dimensional alveolar defects in humans.

• Management of the exposure of e-PTFE membranes in guided bone regeneration.

  Authors: Simone Verardi, Massimo Simion

  Practical procedures & aesthetic dentistry : PPAD. 04/2007; 19(2):111-7.

  Guided bone regeneration (GBR) has been used extensively since its introduction in the late 1980s. In such treatment, e-PTFE membranes are often preferred because of their inert biological featuresGuided bone regeneration (GBR) has been used extensively since its introduction in the late 1980s. In such treatment, e-PTFE membranes are often preferred because of their inert biological features and the predictability of the barrier effect. One complication of GBR is the premature exposure of the membrane. A consequence of the resulting soft tissue dehiscence is compromised bone regeneration. There are situations in which an exposed membrane can be maintained and obtain satisfactory results. This article discusses suggested guidelines for the treatment of exposed e-PTFE membranes. Learning Objectives: This article discusses treatment options for e-PTFE membranes that are exposed with or without infection. Upon reading this article, the reader should: Be able to identify both Class I and Class II exposures. Understand how to properly treat both a Class I and Class II exposed e-PTFE membrane.

• Vertical ridge augmentation with guided bone regeneration in association with dental implants: an experimental study in dogs.

  Authors: Massimo Simion, Christer Dahlin, Isabella Rocchietta, Andreas Stavropoulos, Raquel Sanchez, Thorkild Karring

  Clinical oral implants research. 03/2007; 18(1):86-94.

  AIM: To evaluate the effect of using guided bone regeneration (GBR) with a titanium-reinforced e-PTFE membrane in alveolar bone defects with titanium implants. MATERIAL AND METHODS: FollowingAIM: To evaluate the effect of using guided bone regeneration (GBR) with a titanium-reinforced e-PTFE membrane in alveolar bone defects with titanium implants. MATERIAL AND METHODS: Following extraction of three mandibular premolars and a molar on both sides of the jaw in three dogs, alveolar bone defects (depth: 5-7 mm) were produced. After 4 months, three implants were inserted into each defect to a depth of approximately 4 mm, so that their coronal portion was protruding about 5 mm. Four sides in the dogs were assigned to a test group and the remaining two sides to a control group. The 12 implants in the test group were covered with a reinforced e-PTFE membrane. The space under the membrane was filled with peripheral venous blood from the animal, and the flaps were sutured over the membrane. The six control implants received no membrane before the suturing of the flaps to complete wound closure. The animals were sacrificed after 6 months, and non-decalcified histological specimens of the implants and surrounding tissues were prepared. RESULTS: Histologic and histomorphometric analyses revealed a significantly (Mann-Whitney test; P=0.08) larger amount of bone fill in the test group (mean=57.42%) than in the controls (mean=11.65%), and clinical evaluation of one test site showed that the implants were completely covered with tissue resembling bone. In most of the specimens, bone had grown in height close to, or in direct contact with the membrane. However, the new bone generally was not in direct contact with the implants. Regularly, a zone of dense connective tissue was interposed between the implants and the newly formed bone. CONCLUSION: The formation of even considerable amounts of bone following vertical ridge augmentation with GBR and implants was not accompanied by predictable osseointegration of the implants.

• Vertical ridge augmentation by means of deproteinized bovine bone block and recombinant human platelet-derived growth factor-BB: a histologic study in a dog model.

  Authors: Massimo Simion, Isabella Rocchietta, David Kim, Myron Nevins, Joseph Fiorellini

  The International journal of periodontics & restorative dentistry. 11/2006; 26(5):415-23.

  The primary objective of this proof-of-principle study was to evaluate the outcome of vertical ridge augmentation in a standardized dog model by combining purified recombinant platelet-derived growthThe primary objective of this proof-of-principle study was to evaluate the outcome of vertical ridge augmentation in a standardized dog model by combining purified recombinant platelet-derived growth factor (rhPDGF-BB) and a block of deproteinized cancellous bovine bone. The secondary objective was to determine the value of a resorbable barrier membrane to improve the efficacy of the procedure. Six adult foxhounds were committed to bilateral surgical extraction of all four mandibular premolars. A vertical alveolar ridge defect was created at the time of the extractions. Three months later, the artificially created defects were grafted: Group A used a deproteinized bovine bone block in combination with a collagen barrier membrane, group B used a deproteinized bovine bone block infused with rhPDGF-BB only, and group C included a deproteinized bovine bone block infused with rhPDGF-BB, plus a collagen resorbable barrier membrane. After 4 months, the animals were sacrificed. Histologic examination of group B revealed a large amount of newly formed bone, and a large amount of bone-to-implant contact was visible in the areas of bone regeneration extending over the top of the implant cover screw. The results of this preclinical canine study provide proof-of-principle that rhPDGF-BB, used in combination with a deproteinized bovine block without placement of a barrier membrane, has the potential to regenerate significant amounts of new bone in severe mandibular ridge defects. In addition, the results seem to point to the importance of the periosteum as a source of osteoprogenitor cells in growth factor-mediated regenerative procedures.

• Vertical ridge augmentation around implants using e-PTFE titanium-reinforced membrane and deproteinized bovine bone mineral (bio-oss): A case report.

  Authors: Luigi Canullo, Paolo Trisi, Massimo Simion

  The International journal of periodontics & restorative dentistry. 09/2006; 26(4):355-61.

  The aim of this case report was to evaluate the ability of Bio-Oss used together with an expanded polytetrafluoroethylene, titanium-reinforced membrane to restore a vertical bone defect. Bio-OssThe aim of this case report was to evaluate the ability of Bio-Oss used together with an expanded polytetrafluoroethylene, titanium-reinforced membrane to restore a vertical bone defect. Bio-Oss served as a filler material. After the membrane was removed, screw-type implants were placed. During this phase, cylindric bone samples were retrieved from the augmented area for histologic examination. The biopsy samples were composed of low-density trabecular bone with numerous interspersed graft particles. Clinical and histologic results demonstrated that this surgical technique could be a successful and predictable procedure for rebuilding a resorbed ridge to place implants.

• A study of the fate of the buccal wall of extraction sockets of teeth with prominent roots.

  Authors: Myron Nevins, Marcelo Camelo, Sergio De Paoli, Bernard Friedland, Robert K Schenk, Stefano Parma-Benfenati, Massimo Simion, Carlo Tinti, Barry Wagenberg

  The International journal of periodontics & restorative dentistry. 03/2006; 26(1):19-29.

  The objective of this investigation was to determine the fate of thin buccal bone encasing the prominent roots of maxillary anterior teeth following extraction. Resorption of the buccal plateThe objective of this investigation was to determine the fate of thin buccal bone encasing the prominent roots of maxillary anterior teeth following extraction. Resorption of the buccal plate compromises the morphology of the localized edentulous ridge and makes it challenging to place an implant in the optimal position for prosthetic restoration. In addition, the use of Bio-Oss as a bone filler to maintain the form of the edentulous ridge was evaluated. Nine patients were selected for the extraction of 36 maxillary anterior teeth. Nineteen extraction sockets received Bio-Oss, and seventeen sockets received no osteogenic material. All sites were completely covered with soft tissue at the conclusion of surgery. Computerized tomographic scans were made immediately following extraction and then at 30 to 90 days after healing so as to assess the fate of the buccal plates and resultant form of the edentulous sites. The results were assessed by an independent radiologist, with a crest width of 6 mm regarded as sufficient to place an implant. Those sockets treated with Bio-Oss demonstrated a loss of less than 20% of the buccal plate in 15 of 19 test sites (79%). In contrast, 12 of 17 control sockets (71%) demonstrated a loss of more than 20% of the buccal plate. In conclusion, the Bio-Oss test sites outperformed the control sites by a significant margin. No investigator was able to predict which site would be successful without the grafting material even though all were experienced clinicians. This leads to the conclusion that a patient has a significant benefit from receiving grafting materials at the time of extraction.

• Long-term evaluation of osseointegrated implants placed in sites augmented with sinus floor elevation associated with vertical ridge augmentation: a retrospective study of 38 consecutive implants with 1- to 7-year follow-up.

  Authors: Massimo Simion, Filippo Fontana, Giulio Rasperini, Carlo Maiorana

  The International journal of periodontics & restorative dentistry. 07/2004; 24(3):208-21.

  This clinical study retrospectively evaluated, after 1 to 7 years of prosthetic loading, 38 implants consecutively placed in 16 surgical sites, where severe atrophy of the posterior maxilla wasThis clinical study retrospectively evaluated, after 1 to 7 years of prosthetic loading, 38 implants consecutively placed in 16 surgical sites, where severe atrophy of the posterior maxilla was treated by combining sinus elevation with the vertical ridge regenerative procedure. Two different surgical techniques were adopted. In seven patients (16 implants), implants were placed at the same stage as the regenerative procedures. In the other seven patients (22 implants), implant placement was performed at second-stage surgery, after 6 to 13 months of submerged membrane healing. Each implant was classified as a success, survival, or failure. The distance between the top of the implant shoulder and the first visible bone-implant contact was assessed radiographically for every implant at the mesial and distal sides. Two membranes became exposed during the healing process (12.5%). In the remaining 14 sites (87.5%), the membrane remained covered for a 6- to 13-month healing period. The survival rate of the implants was 92.1%, whereas the success rate was 76.3%. Three implants (7.9%) failed. A comparison of the implant shoulder-bone-implant contact distances between abutment connection and the last examination showed a mean crestal loss of 1.65 mm at the mesial side and 1.68 mm at the distal side. The bone regenerated vertically by means of sinus floor elevation and vertical ridge augmentation showed the same biologic behavior as native, nonregenerated bone; however, in a few cases, its remodeling pattern seemed to determine slightly higher bone crest resorption.