Horizontal ridge augmentation using GBR with a native collagen membrane and 1:1 ratio of particulate xenograft and autologous bone: A 3-year after final loading prospective clinical study.

BACKGROUND: Cawood-Howell class IV atrophies, also known as "knife-edge" ridges, represent a serious horizontal defect, making the placement of regular implants challenging. AIM: To clinically and radiographically evaluate bone regeneration of severe horizontal bone defects with 3 years of follow-up. MATERIALS AND METHODS: This study was designed as a single cohort, prospective clinical trial. Patients having horizontal bone width of 4 mm or less in the posterior mandible or maxilla were treated with resorbable collagen membranes and a 1:1 mixture of anorganic bovine bone (ABB) and autogenous bone. Implants were inserted and loaded 7 months later. Outcomes were implant and prosthetic survival rates, any biological and prosthetic complications, horizontal and volumetric bone dimensional changes measured on cone beam computer tomography (CBCT), peri-implant marginal bone level (MBL) changes measured on periapical radiographs, plaque index (PI), and bleeding on probing (BOP). RESULTS: Eighteen patients received 55 implants. No patient dropped-out. No implant and prosthetic failures and no complications were recorded. Super imposition of pre and 7-month postoperative CBCT scans revealed an average horizontal bone gain of 5.03 ± 2.15 mm (95% CI: 4.13-5.92 mm). After 3 years, mean MBL was 1.15 ± 0.28 mm (95% CI 0.84-1.22 mm). The PI was 11.6%, and BOP was 5.2%. CONCLUSION: Within the limitations of the present study, high implant survival rate and high average bone augmentation seem to validate the use of collagen resorbable membranes with a 1:1 mixture of particulate ABB and autogenous bone for the reconstruction of Cawood-Howell class IV alveolar ridge atrophies.

One-stage horizontal guided bone regeneration with autologous bone, anorganic bovine bone and collagen membranes: Follow-up of a prospective study 30 months after loading.

PURPOSE: To present the medium-term results of one-stage guided bone regeneration (GBR) using autologous bone and anorganic bovine bone, placed in layers, in association with resorbable collagen membranes, for the reconstruction of horizontal bony defects. MATERIALS AND METHODS: This study was designed as an uncontrolled prospective study. Partially edentulous patients, having less than 6.0 mm and more than 4.0 mm of residual horizontal bone width were selected and consecutively treated with simultaneously implant installation and bone regeneration by using 2.0 mm of autologous bone and 2.0 mm of anorganic bovine bone that was placed in layers and then covered with a resorbable collagen membrane. Outcome measures were: implant and prosthesis failures, any complications, peri-implant marginal bone level changes, probing pocket depth (PPD) and bleeding on probing (BOP). RESULTS: In total, 45 consecutive patients (20 male, 25 female) with a mean age of 52.1 years each received at least one GBR procedure, with contemporary placement of 63 implants. At the 3-year follow-up examination, no patient had dropped out and no deviation from the original protocol had occurred. No implant or prosthesis failed. In six patients (13.3%) the collagen membrane was slightly exposed 1 to 2 weeks after bone reconstruction. Four of these patients were moderate smokers. Post-hoc analysis using Fisher's exact test found significant association (P = 0.0139) between a smoking habit and early membrane exposure. Mean marginal bone loss experienced between initial loading and 30 months afterwards was 0.60 ± 0.20 mm (95% CI 0.54 - 0.66). The mean BOP values measured at the definitive restoration delivery were 1.23 ± 0.93, while 2 years later they were 1.17 ± 0.78. The difference was not statistically significant (-0.06 ± 0.76; P = 0.569). The mean PPD values measured at the definitive restoration delivery were 2.62 ± 0.59 mm, while 2 years later they were 2.60 ± 0.54 mm. The difference was not statistically significant (-0.03 ± 0.62; P = 0.765). CONCLUSIONS: Within the limitations of the present study, the use of a 2.0 mm layer of particulated autologous bone on the implant threads, and a 2.0 mm layer of anorganic bovine to cover the resorbed ridge, in combination with the resorbable collagen membrane, seems to be a viable treatment option for the reconstruction of horizontal bony defects.

Sinus lift grafting with anorganic bovine bone vs 50% autologous bone mixed with 50% anorganic bovine bone: 2 years after loading results from a randomised controlled trial.

PURPOSE: To compare the outcome of implants inserted in maxillary sinuses augmented with anorganic bovine bone (ABB) grafts vs mixed 50% ABB and 50% autologous bone graft, using a lateral window approach. MATERIALS AND METHODS: This study was designed as a randomised controlled trial of parallel groups. Patients in need of an implant-supported prosthesis in a maxillary posterior area with a residual alveolar bone height no greater than 4 mm (range 0-4 mm) were recruited for lateral sinus grafting. Patients were randomly allocated to receive 50% ABB and 50% autogenous bone (group A) or 100% ABB (group B). After 7 months, tapered implants were inserted with an insertion torque between 20 and 45 Ncm. After 3 months, implants were loaded with screw-retained temporary crowns. Definitive crowns were delivered 3 months later. Outcome measures were implant survival, complications, radiographic marginal bone-level changes, probing pocket depths (PPD) and bleeding on probing (BOP). Clinical data were collected at definitive prosthesis delivery, 1 and 2 years after loading. RESULTS: Thirty-two consecutive patients were treated with 32 sinus lift procedures (16 group A, 16 group B). A total of 46 implants were installed. No patient dropped out. No crown/implant failed by the end of the study. Three complications (one sinus membrane perforation and two chipping of the ceramic) were observed in three patients in group A, vs none in group B (RR 0.81; 95% CI 0.64 - 1.03 mm; P = 0.225). At the 2-year after final loading follow-up, the mean marginal bone loss was 1.18 ± 0.50 mm (95% CI 0.95 - 1.45 mm) in group A and 1.28 ± 0.48 mm (95% CI 0.97 - 1.43 mm) in group B, with no statistically significant differences between the two groups (difference 0.11 ± 0.22 mm; 95% CI -0.06 - 0.16 mm; P = 0.586). At the same follow-up, the mean PPD value was 2.70 ± 0.39 for group A and 2.54 ± 0.66 for group B, with no statistically significant difference between groups (difference 0.17 ± 0.39 mm; 95% CI 0.06 - 0.32 mm; P = 0.456), while the mean BOP value was 1.21 ± 0.79 for group A and 1.28 ± 0.68 for group B, (difference: 0.06 ± 0.49 mm; 95% CI -0.23 - 0.25 mm; P = 0.297). CONCLUSIONS: Within the limitations of this study, the present data seem to confirm the hypothesis that the clinical outcome of implants inserted in sinuses grafted with ABB vs implants inserted in sinuses grafted with mixed 50% ABB and 50% autologous bone are comparable. Conflict-of-interest statement: This study was not supported by any company. All the authors declare no conflict of interest.

Horizontal Ridge Augmentation using GBR with a Native Collagen Membrane and 1:1 Ratio of Particulated Xenograft and Autologous Bone: A 1-Year Prospective Clinical Study.

AIM: To clinically and radiographically evaluate bone regeneration of severe horizontal bone defects. MATERIALS AND METHODS: This study was designed as a single cohort, prospective clinical trial. Partially or fully edentulous patients, having less then 4 mm of residual horizontal bone width were selected and consecutively treated with resorbable collagen membranes and a 1:1 mixture of particulated anorganic bovine bone and autogenous bone, 7 months before implant placement. Tapered body implants were inserted and loaded 3 to 6 months later with a screw retained crown or bridge. Outcomes were: implant survival rate, any biological and prosthetic complications, horizontal alveolar bone dimensional changes measured on cone beam computed tomography (CBCT) taken at baseline and at implant insertion, peri-implant marginal bone level changes measured on periapical radiographs, plaque index (PI), and bleeding on probing index (BoP). RESULTS: Eighteen consecutive patients (11 females, 7 males) with a mean age of 56.8 years (range 24-78) and 22 treated sites received 55 regular platform implants. No patient dropped-out and no implants failed during the entire follow-up, resulting in a cumulative implant survival rate of 100%. No prosthetic or biological complications were recorded. Supraimposition of pre- and 7-month post-operative CBCT scans revealed an average horizontal bone gain of 5.03 ± 2.15 mm (95% CI: 4.13-5.92 mm). One year after final prosthesis delivery, mean marginal bone loss was 1.03 ± 0.21 mm (95% CI 0.83-1.17 mm). PI was 11.1% and BoP was 5.6%. CONCLUSION: Within the limitation of the present study, high implant survival rate and high average bone augmentation seem to validate the use of collagen resorbable membranes with a 1:1 mixture of particulated anorganic bovine bone and autogenous bone, for the reconstruction of severe horizontal ridge defects.

Platform switching versus regular platform implants: 3-year post-loading results from a randomised controlled trial.

PURPOSE: To test the hypothesis that platform switching and regular platform implants would have different outcomes in single-tooth replacement against the alternative hypothesis of no difference. MATERIAL AND METHODS: This study was designed as a randomised controlled split-mouth trial. Eighteen patients with bilaterally missing single premolars or molars to be restored with implant-supported single crowns, were consecutively enrolled. Implant sites were randomly assigned to be treated according to the platform switching concept (PS group), or with matching implant-abutment diameters (RP group). A total of 36 Nobel Replace Tapered Groovy implants were installed. All the implants were inserted in healed bone, with an insertion torque between 35 and 45 Ncm, according to a one-stage protocol. Both implant types were loaded with a screw-retained temporary crown 3 months after implant insertion. Definitive screw-retained single crowns were delivered 2 months later. Outcome measures were implant and prosthetic survival rates, biological and prosthetic complications, radiographic marginal bone level (MBL) changes, pocket probing depth (PPD) and bleeding on probing (BOP). Clinical data was collected at implant placement (baseline), and at 3, 9 and 36 months after loading. RESULTS: No patients dropped out and no implant failed. No prosthetic complications were recorded. One patient experienced mucosal inflammation with positive BOP (RP group) after 3 months, three patients had bilateral peri-implant mucosal inflammation with positive BOP at 6, 24 and 30 months after loading, respectively. There were no statistically significant differences between groups for complications (3/18 versus 4/18; P = 1.0; Odds Ratio = 1.333; 95% CI: 0.3467 to 5.1272). Nine months after loading, the mean MBL was 0.93 ±â€…0.26 mm in the RP group and 0.84 ±â€…0.23 mm in the PS group, with no statistically significant differences between groups (mean difference = 0.09 mm, 95% CI: -0.22 to 0.04, P = 0.18). Three years after loading, mean MBL was 1.09 ±â€…0.31 mm in the RP group and 1.06 ±â€…0.24 mm in the PS group, with no statistically significant differences between groups (mean difference = 0.02 mm, 95% CI: -0.06 to 0.10, P = 0.70). Marginal bone level changes between 3 years and baseline were 0.72 ±â€…0.28 mm in the RP group and 0.71 ±â€…0.27 mm in the PS group, with no statistically significant differences between the groups (mean difference = -0.00 mm, 95% CI: -0.07 to 0.07, P = 0.89). Mean PPD was 2.70 ±â€…0.52 mm in the RP group and 2.46 ±â€…0.69 mm in the PS group at 36 months after loading, with no statistically significant differences between the groups (mean difference = 0.23 mm, 95% CI: -0.05 to 0.35, P = 0.43). Mean BOP was 0.83 ±â€…0.96 mm in the RP group and 0.89 ±â€…0.99 mm in the PS group at 36 months after loading, with no statistically significant differences between the groups (mean difference = 0.07 mm, 95% CI: -0.03 to 0.17, P = 0.77). Conclusions: The clinical and radiographic outcomes of implants restored according to the platform-switching concept versus implants restored with the matching implant-abutment diameters are comparable, 3 years after loading. Conflict of interest statement: This study was not supported by any company. All authors declare no conflict of interest.

Postextraction socket preservation using epithelial connective tissue graft vs porcine collagen matrix. 1-year results of a randomised controlled trial.

PURPOSE: To compare epithelial connective tissue graft vs porcine collagen matrix for sealing postextraction sockets grafted with deproteinised bovine bone. MATERIALS AND METHODS: A total of 30 patients, who needed a maxillary tooth to be extracted between their premolars and required a delayed, fixed, single implant-supported restoration, had their teeth atraumatically extracted and their sockets grafted with deproteinised bovine bone. Patients were randomised according to a parallel group design into two arms: socket sealing with epithelial connective tissue graft (group A) vs porcine collagen matrix (group B). Outcome measures were: implant success and survival rate, complications, horizontal and vertical alveolar bone dimensional changes measured on Cone Beam computed tomography (CBCT) scans at three levels localised 1, 3, and 5 mm below the most coronal aspect of the bone crest (levels A, B, and C); and between the palatal and buccal wall peaks (level D); and peri-implant marginal bone level changes measured on periapical radiographs. RESULTS: 15 patients were randomised to group A and 15 to group B. No patients dropped out. No failed implants or complications were reported 1 year after implant placement. Five months after tooth extraction there were no statistically significant differences between the 2 groups for both horizontal and vertical alveolar bone dimensional changes. At level A the difference was 0.13 ± 0.18; 95% CI 0.04 to 0.26 mm (P = 0.34), at level B it was 0.08 ± 0.23; 95% CI -0.14 to 0.14 (P = 0.61), at level C it was 0.05 ± 0.25; 95% CI -0.01 to 0.31 mm (P = 0.55) and at level D it was 0.13 ± 0.27; 95% CI -0.02 to 0.32 mm (P = 0.67). One year after implant placement there were no statistically significant differences between the 2 groups for peri-implant marginal bone level changes (difference: 0.07 ± 0.11 mm; 95% CI -0.02 to 0.16; P = 0.41). CONCLUSIONS: When teeth extractions were performed atraumatically and sockets were filled with deproteinised bovine bone, sealing the socket with a porcine collagen matrix or a epithelial connective tissue graft showed similar outcomes. The use of porcine collagen matrix allowed simplification of treatment because no palatal donor site was involved.

Partial lateralization of the nasopalatine nerve at the incisive foramen for ridge augmentation in the anterior maxilla prior to placement of dental implants: a retrospective case series evaluating self-reported data and neurosensory testing.

The objective of this study was to assess implant therapy after a staged guided bone regeneration procedure in the anterior maxilla by lateralization of the nasopalatine nerve and vessel bundle. Neurosensory function following augmentative procedures and implant placement, assessed using a standardized questionnaire and clinical examination, were the primary outcome variables measured. This retrospective study included patients with a bone defect in the anterior maxilla in need of horizontal and/or vertical ridge augmentation prior to dental implant placement. The surgical sites were allowed to heal for at least 6 months before placement of dental implants. All patients received fixed implant-supported restorations and entered into a tightly scheduled maintenance program. In addition to the maintenance program, patients were recalled for a clinical examination and to fill out a questionnaire to assess any changes in the neurosensory function of the nasopalatine nerve at least 6 months after function. Twenty patients were included in the study from February 2001 to December 2010. They received a total of 51 implants after augmentation of the alveolar crest and lateralization of the nasopalatine nerve. The follow-up examination for questionnaire and neurosensory assessment was scheduled after a mean period of 4.18 years of function. None of the patients examined reported any pain, they did not have less or an altered sensation, and they did not experience a "foreign body" feeling in the area of surgery. Overall, 6 patients out of 20 (30%) showed palatal sensibility alterations of the soft tissues in the region of the maxillary canines and incisors resulting in a risk for a neurosensory change of 0.45 mucosal teeth regions per patient after ridge augmentation with lateralization of the nasopalatine nerve. Regeneration of bone defects in the anterior maxilla by horizontal and/or vertical ridge augmentation and lateralization of the nasopalatine nerve prior to dental implant placement is a predictable surgical technique. Whether or not there were clinically measurable impairments of neurosensory function, the patients did not report them or were not bothered by them.

Platform switching vs regular platform implants: nine-month post-loading results from a randomised controlled trial.

PURPOSE: To compare the clinical outcome of platform switching (PS) and regular platform (RP) implants in bilateral single molar replacements. MATERIAL AND METHODS: This study was designed as a randomised, controlled, split-mouth trial. Eighteen patients, with bilaterally missing single molars had one site randomly assigned to a PS implant or a RP implant. A total of 36 implants were bilaterally installed. Both implants were loaded with screw retained temporary crowns 3 months after implant insertion and with screw retained definitive crowns 3 months later. Outcome measures were implant/crown failure, complications, radiographic marginal bone-level changes, pocket probing depth (PPD) and bleeding on probing (BOP). Clinical data were collected at baseline 6 and 12 months after implant placement. RESULTS: No patients dropped out and no implant failed. No prosthetic or major biological complications were observed. One year after implant placement, mean marginal bone level was 0.93 ± 0.26 mm (95% CI 0.81 to 1.05) in RP group and 0.84 ± 0.23 mm (95% CI 0.73 to 0.95) in the PS group and no statistically significant differences between the two groups were observed (P = 0.18). Mean PPD and BOP values were, 6 and 12 months after implant placement, 2.74 ± 0.49 mm (95% CI 2.51 to 2.97) and 1.28 ± 0.75 (95% CI 0.93 to 1.63) in the RP group, and 2.70 ± 0.38 mm (95% CI 2.53 to 2.88) and 1.39 ± 0.78 (95% CI 1.03 to 1.75) in the PS group respectively, with no statistical differences between groups (P = 0.81 and P = 0.16, respectively). CONCLUSIONS: No statistically significant difference was observed between platform switched and non-platform switched implants.

Prevalence of peri-implantitis in patients with implant-supported fixed prostheses.

OBJECTIVE: The purpose of this study was to evaluate periimplantitis prevalence in patients using implant-supported fixed prostheses that did not have any routine maintenance care. METHOD AND MATERIALS: A total of 161 implants (27 patients) were evaluated in patients using implant-supported fixed prostheses. Collected data included information related to patient general health and local factors such as characteristics of implants, time in function, type of loading, positioning, Modified Bleeding Index, bacterial plaque, bleeding on probing (BOP), marginal recession, probing depth (PD), keratinized mucosa, and radiographic bone loss (BL). Factors related to the prostheses were also evaluated. The exclusion criteria were patients that have had any follow-up visit for plaque control of the prosthesis and/or the implants. RESULTS: From a total of 161 implants, 116 (72%) presented without peri-implantitis (PD > 4 mm + BOP + BL > 2 mm) while 45 (28%) had some sign of the disease. Implants placed in the maxilla were 2.98 times more likely to develop the disease (P < .05). Moreover, patients aged ≤ 60 years old were 3.24 times more likely to develop peri-implantitis (P < .05). Another analysis with statistical relevance (P < .05) was that implants with less than 3 mm interimplant distance were three times more likely to have peri-implantitis. There was no statistical relevance considering other analyses. CONCLUSION: It can be concluded that patients aged ≤ 60 years have a greater chance of presenting periimplantitis, as well as for implants positioned in the maxilla and those placed with an interimplant distance < 3 mm.

The "All-on-4" concept for implant rehabilitation of an edentulous jaw.

Complete edentulism is a significant oral health burden associated with a reduction of overall health and quality of life. Osseointegrated implant prostheses offer a number of substantial advantages compared with conventional dentures. Traditional implant therapy, however, requires a period of at least 3 months of osseointegration to load a definitive prosthesis onto an implant. The "All-on-4" treatment concept facilitates immediate function and esthetics, along with various benefits that are associated with efficacious long-term outcomes and patient satisfaction. This article discusses considerations for All-on-4 treatment and presents methodological descriptions for the effective use of this treatment concept.

Vertical ridge augmentation with titanium-reinforced, dense-PTFE membranes and a combination of particulated autogenous bone and anorganic bovine bone-derived mineral: a prospective case series in 19 patients.

PURPOSE: This prospective case series evaluated the use of a new titanium-reinforced nonresorbable membrane (high-density polytetrafluoroethylene), in combination with a mixture of anorganic bovine bone-derived mineral (ABBM) and autogenous particulated bone, for vertical augmentation of deficient alveolar ridges. MATERIALS AND METHODS: A mixture of ABBM and autogenous particulated bone was used for vertical ridge augmentation and covered with a new titanium-reinforced nonresorbable membrane. Ridge measurements were obtained before and after the procedure, complications were recorded, and biopsy specimens were taken for histologic examination. RESULTS: Twenty vertical ridge augmentation procedures were carried out in 19 patients. All treated defect sites exhibited excellent bone formation, with an average bone gain of 5.45 mm (standard deviation 1.93 mm). The healing period was uneventful, and no complications were observed. Eight specimens were examined histologically; on average, autogenous or regenerated bone represented 36.6% of the specimens, ABBM 16.6%, and marrow space 46.8%. No inflammatory responses or foreign-body reactions were noted in the specimens. CONCLUSION: The treatment of vertically deficient alveolar ridges with guided bone regeneration using a mixture of autogenous bone and ABBM and a new titanium-reinforced nonresorbable membrane can be considered successful.

Horizontal guided bone regeneration in the posterior maxilla using recombinant human platelet-derived growth factor: a case report.

This clinical case report describes and demonstrates the successful use of purified recombinant human platelet-derived growth factor in conjunction with autogenous bone, an organic bovine bone-derived mineral, and a barrier membrane to reconstruct severe alveolar bone defects. Significant horizontal bone regeneration was achieved in the posterior maxillary region. Three implants were placed into the newly formed ridge and demonstrated stable crestal bone after 36 months of loading.

Definitive abutment-driven stage-two surgery as a means to reduce peri-implant soft tissue changes: introduction of a new concept.

This report introduces an innovative approach for optimizing esthetics and minimizing soft tissue changes in clinical scenarios that involve extensive site preparation and submerged implants. The existing soft tissue morphology is registered at the time of implant uncovery, and an optimal peri-implant transmucosal contour is created indirectly in the lab. The customized definitive abutment is inserted during stage-two surgery and subsequently guides the peri-implant soft tissue, replicating an optimal emergence profile. The concept is demonstrated through the presentation of two clinical cases.

Vertical ridge augmentation using guided bone regeneration (GBR) in three clinical scenarios prior to implant placement: a retrospective study of 35 patients 12 to 72 months after loading.

PURPOSE: The aims of the current study were to: (1) evaluate the results of vertical guided bone regeneration (GBR) with particulate autogenous bone grafts, (2) determine clinically and radiographically the success and survival rates of 82 implants placed in such surgical sites after prosthetic loading for 12 to 72 months, and (3) compare defects that were treated simultaneously with sinus augmentation and vertical GBR to other areas of the jaw treated with vertical GBR only. MATERIALS AND METHODS: Eighty-two implants were inserted in 35 patients with 36 three-dimensional vertical bone defects. The patients were divided into three groups: single missing teeth (group A), multiple missing teeth (group B), and vertical defects in the posterior maxilla only (group C). All group C subjects were treated simultaneously with sinus and vertical augmentations. All patients were treated with vertical ridge augmentation utilizing titanium-reinforced polytetrafluoroethylene (e-PTFE) membranes and particulated autografts. After removal of the e-PTFE membrane, all sites received a collagen membrane. RESULTS: At membrane removal, mean vertical augmentation was 5.5 mm (+/-2.29 mm). Mean combined crestal remodeling was 1.01 mm (+/-0.57 mm) at 12 months, which remained stable through the 6-year follow-up period. There were no statistically significant differences between the three groups in mean marginal bone remodeling. One defect had a bone graft complication (2.78%, 95% CI: 0.00%, 8.15%). The overall implant survival rate was 100% with a cumulative success rate of 94.7%. CONCLUSIONS: (1) Vertical augmentation with e-PTFE membranes and particulated autografts is a safe and predictable treatment; (2) success and survival rates of implants placed in vertically augmented bone with the GBR technique appear similar to implants placed in native bone under loading conditions; (3) success and failure rates of implants placed into bone regenerated simultaneously with sinus and vertical augmentation techniques compare favorably to those requiring only vertical augmentation.

An esthetic solution for single-implant restorations - type III porcelain veneer bonded to a screw-retained custom abutment: a clinical report.

A new esthetic solution to restore dental implants in combination with limited interdental, facial or labial, or interocclusal space is presented. This article describes the translational application of novel-design porcelain veneers and adhesive restorative principles in the implant realm. A patient is presented who was treated with a single implant-supported restoration replacing a missing mandibular lateral incisor and partially collapsed interdental space. A screw-retained custom metal ceramic abutment was combined with a bonded porcelain restoration. This unique design was motivated by the limited restorative space and subgingival implant shoulder. It was also developed as a solution to the interference of the screw-access channel with the incisal edge, therefore providing the surgeon with more options during implant axis selection. The porcelain-to-porcelain adhesive approach was used instead of traditional principles of retention and resistance form of the abutment.

Bone rehabilitation to achieve optimal aesthetics.

Treatment involving oral implants has established a high success rate, including implant survival on a long-term basis. The challenge facing the clinicians today is to achieve an optimal long-term aesthetic result. To address this challenge, the volume of the underlying hard and soft tissue must be restored either prior to or simultaneously with the implant placement. The learning objective of this article is to review the critical biologic and clinical criteria essential in achieving a predictable success in aesthetic enhancement of the implant site.

Bone reconstruction following implantation of rhBMP-2 and guided bone regeneration in canine alveolar ridge defects.

BACKGROUND: Alveolar ridge aberrations commonly require bone augmentation procedures for optimal placement of endosseous dental implants. The objective of this study was to evaluate local bone formation following implantation of recombinant human bone morphogenetic protein-2 (rhBMP-2) in an absorbable collagen sponge (ACS) carrier with or without provisions for guided bone regeneration (GBR) as potential treatment modalities for alveolar augmentation. METHODS: Surgically induced, large, mandibular alveolar ridge saddle-type defects (2 defects/jaw quadrant) in seven young adult Hound dogs were assigned to receive rhBMP-2/ACS, rhBMP-2/ACS combined with GBR (rhBMP-2/GBR), GBR, and surgery controls. The animals were euthanized at 12 weeks post-surgery when block sections of the defect sites were collected for histologic analysis. RESULTS: Clinical complications included swelling for sites receiving rhBMP-2 and wound failure with exposure of the barrier device for sites receiving GBR (4/6) or rhBMP-2/GBR (3/7). The radiographic evaluation showed substantial bone fill for sites receiving rhBMP-2/ACS, rhBMP-2/GBR, and GBR. In particular, sites receiving rhBMP-2/GBR presented with seroma-like radiolucencies. The surgery control exhibited moderate bone fill. To evaluate the biologic potential of the specific protocols, sites exhibiting wound failure were excluded from the histometric analysis. Sites receiving rhBMP-2/ACS or rhBMP-2/GBR exhibited bone fill averaging 101%. Bone fill averaged 92% and 60%, respectively, for sites receiving GBR and surgery controls. Bone density ranged from 50% to 57% for sites receiving rhBMP-2/ACS, GBR, or surgery controls. Bone density for sites receiving rhBMP-2/GBR averaged 34% largely due to seroma formation encompassing 13% to 97% of the sites. CONCLUSION: rhBMP-2/ACS appears to be an effective alternative to GBR in the reconstruction of advanced alveolar ridge defects. Combining rhBMP-2/ACS with GBR appears to be of limited value due to the potential for wound failure or persistent seromas.

Esthetic therapy with standard and scalloped implant designs: the five biologic elements for success.

The field of implant dentistry has grown significantly in recent years. Balancing natural-looking esthetics with long-term function, however, remains a challenging task. The main focus of implant dentistry is on improving the survival rate, simplifying the treatment, improving the esthetic outcome, and reducing the treatment time. Developing a natural contour and anatomically dimensioned soft-tissue margin is critical to attaining an esthetic implant restoration. This article discusses the five elements to achieve natural implant esthetics: bone foundation, implant design and placement, soft-tissue profile, prosthetic tissue support, and ceramic art design.

Long-term functional loading of dental implants in rhBMP-2 induced bone. A histologic study in the canine ridge augmentation model.

Osseointegration [direct bone-implant contact (BIC)] is a primary goal following installation of endosseous dental implants. Such bone contact provides stability for the dental implant over time. The objective of this study was to evaluate bone formation and BIC at long-term, functionally loaded, endosseous dental implants placed into bone induced by recombinant human bone morphogenetic protein-2 (rhBMP-2) in an absorbable collagen sponge (ACS) carrier. Mandibular, saddle-type, alveolar ridge defects (approximately 15 x 10 x 10 mm), two per jaw quadrant, were surgically induced in each of six young adult American fox hounds. The defects were immediately implanted with rhBMP-2/ACS. Two defects per animal additionally received a nonresorbable expanded polytetrafluoroethylene (ePTFE) membrane or a bioresorbable polyglycolide fiber membrane. Healing was allowed to progress for 3 months, when the ePTFE membrane was removed, and machined, threaded, titanium dental implants were installed into the rhBMP-2/ACS induced bone and into the adjacent resident bone. At 4 months of osseointegration, the implants were exposed to receive abutments and prosthetic treatment (two- or three-unit bridges). Some implants were removed for histologic analysis. The remainder of implants were exposed to functional loading for 12 months at which time the animals were killed for histometric analysis. One animal died prematurely due to kidney failure unrelated to the experimental protocol and was not included in the analysis. The 12-month block sections from a second animal were lost in the histological processing. Four sites receiving rhBMP-2/ACS and ePTFE or resorbable membranes experienced wound failure and membrane exposure, and subsequently exhibited limited bone formation. Defects without wound failure filled to contour with the adjacent alveolar bone. The newly formed bone exhibited features of the resident bone with a re-established cortex; however, it commonly included radiolucent areas that resolved over time. Dental implants block biopsied at 4 months exhibited limited, if any, crestal resorption, whereas those exposed to functional loading for 12 months exhibited some crestal resorption. Implants biopsied at 4 months exhibited a mean (+/- SD) BIC of 40.6 +/- 8.2% in rhBMP-2/ACS induced bone vs. 52.7 +/- 11.4% in resident bone. Dental implants exposed to 12 months of functional loading exhibited a mean BIC of 51.7 +/- 7.1% in rhBMP-2/ACS induced bone vs. 74.7 +/- 7.0% in resident bone. There were no significant differences between dental implants placed into rhBMP-2/ACS induced bone and resident bone for any parameter at any observation interval. In conclusion, rhBMP-2/ACS-induced bone allows installation, osseointegration, and long-term functional loading of machined, threaded, titanium dental implants in dogs.

The Management of Peri-implant Breakdown Around Functioning Osseointegrated Dental Implants.

Peri-implant tissue breakdown can be the result of microbial action as well as of biomechanical and occlusal overload. The long-term goal of the treatment of peri-implant breakdown is to arrest the progression of the disease and to achieve a maintainable site for the patient. Peri-implant bony defects around functioning implants can be treated with either non-surgical or surgical (resective or regenerative) techniques. Bone regeneration is possible in selected peri-implant bony defects of functioning implants if appropriate surgical techniques are utilized and the etiologic cause is eradicated. J Periodontol 1993; 64:1176-1183.