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The efficacy of horizontal and vertical bone augmentation procedures for dental implants - a Cochrane systematic review.

BACKGROUND dental implants require sufficient bone to be adequately stabilised. For some patients implant treatment would not be an option without horizontal or vertical bone augmentation. A variety of materials and surgical techniques are available for bone augmentation. OBJECTIVES to test whether and when augmentation procedures are necessary and which is the most effective technique for horizontal and vertical bone augmentation. SEARCH METHODS the Cochrane Oral Health Groups Trials Register, the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE and EMBASE were searched. Several dental journals were hand searched. The bibliographies of review articles were checked, and personal references were searched. More than 55 implant manufacturing companies were also contacted. The last electronic search was conducted on 11 June 2009. SELECTION CRITERIA randomised controlled trials (RCTs) of different techniques and materials for augmenting bone horizontally and/or vertically for implant treatment that reported the outcome of implant therapy at least to abutment connection. Trials were divided into two broad categories: horizontal augmentation and vertical augmentation techniques. DATA COLLECTION AND ANALYSIS screening of eligible studies, assessment of the methodological quality of the trials and data extraction were conducted independently and in duplicate. Authors were contacted for any missing information. Results were expressed as random-effects models using mean differences for continuous outcomes and odds ratios (OR) for dichotomous outcomes with 95% confidence intervals (CI). The statistical unit of the analysis was the patient. RESULTS 13 RCTs out of 18 potentially eligible trials were suitable for inclusion. Three RCTs (106 patients) dealt with horizontal and 10 trials (218 patients) with vertical augmentation. Since different techniques were evaluated in different trials, only one meta-analysis could be performed. When comparing whether vertical augmentation procedures were more advantageous than short implants, a meta-analysis of two trials resulted in more implant failures OR = 5.74 (95% CI 0.92 to 35.82; borderline significance, P = 0.06) and statistically significantly more complications OR = 4.97 (95% CI 1.10 to 22.40) in the vertically augmented group. When comparing various horizontal augmentation techniques (three trials) no statistically significant differences were observed. When comparing various vertical bone augmentation techniques (eight trials) no statistically significant differences were observed except for three trials which showed that more vertical bone gain could be obtained with osteodistraction than with inlay autogenous grafts (mean difference 3.25 mm; 95% CI 1.66 to 4.84), and with bone substitutes rather than autogenous bone in guided bone regeneration (mean difference 0.60 mm; 95% CI 0.21 to 0.99) in posterior atrophic mandibles, and that patients preferred a bone substitute block over a block of autogenous bone taken from the iliac crest (OR = 0.03; 95% CI 0.00 to 0.64; P = 0.02). CONCLUSIONS conclusions are based on few trials including few patients, sometimes having a short follow-up, and often being judged to be at high risk of bias. Various techniques can augment bone horizontally and vertically, but it is unclear which are the most efficient. Short implants appear to be a better alternative to vertical bone grafting of resorbed mandibles. Complications, especially for vertical augmentation, are common. Some bone substitutes could be a preferable alternative to autogenous bone. Osteodistraction osteogenesis allows for more vertical bone augmentation than other techniques, which, on the other hand, can allow for horizontal augmentation at the same time. Titanium screws may be preferable to resorbable screws to fixate onlay bone grafts.

Alveolar distraction osteogenesis versus inlay bone grafting in posterior mandibular atrophy: a prospective study

OBJECTIVE The objective of this study was to compare bone gain, implant survival, implant success, bone resorption, and complication rate in groups of patients who underwent distraction osteogenesis (DO) and inlay bone grafting (Inlay) for preprosthetic issues in the atrophic posterior mandible. STUDY DESIGN Twelve surgical sites were randomly assigned to 2 treatment groups: group A: DO and group B: Inlay. After 3 to 4 months, 16 fixtures in the DO group and 21 in the Inlay group were placed for fixed prosthetic rehabilitation. The median follow-up was 26 months. RESULTS The median bone gain was 10 versus 5.8 mm (DO versus Inlay, P = .003); the median bone resorption was 1.4 mm versus 0.9 mm (DO versus Inlay, P = .088). The implant survival rate was 100% for each group, while the implant success rate was 93.7% (DO) versus 95.2% (Inlay) (P > .05). The complication rate was 60% for DO and 14.3% for Inlay (P < .05). CONCLUSION DO obtained more vertical bone gain than Inlay, but was more prone to complications in the pre-implantology phase. The implant results in each group were comparable to those in native alveolar bone.

Vertical ridge augmentation of the atrophic posterior mandible with interpositional bloc grafts: bone from the iliac crest vs bovine anorganic bone. Clinical and histological results up to one year after loading from a randomized-controlled clinical trial.

OBJECTIVES To compare two different techniques for vertical bone augmentation of the posterior mandible: bone blocs from the iliac crest vs. anorganic bovine bone blocs used as inlays. MATERIALS AND METHODS Ten partially edentulous patients having 5-7 mm of residual crestal height above the mandibular canal had their posterior mandibles randomly allocated to both interventions. After 4 months implants were inserted, and after 4 months, provisional prostheses were placed. Definitive prostheses were delivered after 4 months. Histomorphometry of samples trephined at implant placement, prosthesis and implant failures, any complication after loading and peri-implant marginal bone-level changes were assessed by masked assessors. All patients were followed up to 1 year after loading. RESULTS Four months after bone augmentation, there was statistically significant more residual graft (between 10% and 13%) in the Bio-Oss group. There were no statistically significant differences in failures and complications. Two implants could not be placed in one patient augmented with autogenous bone because the graft failed whereas one implant and its prosthesis of the Bio-Oss group failed after loading. After implant loading only one complication (peri-implantitis) occurred at one implant of the autogenous bone group. In 16 months (from implant placement to 1 year after loading), both groups lost statistically significant amounts of peri-implant marginal bone: 0.82 mm in the autogenous bone group and 0.59 mm in the Bio-Oss group; however, there were no statistically significant differences between the groups. CONCLUSIONS Both procedures achieved good results, but the use of bovine blocs was less invasive and may be preferable than harvesting bone from the iliac crest.

Vertical augmentation with interpositional blocks of anorganic bovine bone vs. 7-mm-long implants in posterior mandibles: 1-year results of a randomized clinical trial

OBJECTIVES To evaluate whether 7-mm-long implants could be an alternative to longer implants placed in vertically augmented posterior mandibles. MATERIALS AND METHODS Sixty patients with posterior mandibular edentulism with 7-8 mm bone height above the mandibular canal were randomized to either vertical augmentation with anorganic bovine bone blocks and delayed 5-month placement of ≥10 mm implants or to receive 7-mm-long implants. Four months after implant placement, provisional prostheses were delivered, replaced after 4 months, by definitive prostheses. The outcome measures were prosthesis and implant failures, any complications and peri-implant marginal bone levels. All patients were followed to 1 year after loading. RESULTS One patient dropped out from the short implant group. In two augmented mandibles, there was not sufficient bone to place 10-mm-long implants possibly because the blocks had broken apart during insertion. One prosthesis could not be placed when planned in the 7 mm group vs. three prostheses in the augmented group, because of early failure of one implant in each patient. Four complications (wound dehiscence) occurred during graft healing in the augmented group vs. none in the 7 mm group. No complications occurred after implant placement. These differences were not statistically significant. One year after loading, patients of both groups lost an average of 1 mm of peri-implant bone. There no statistically significant differences in bone loss between groups. CONCLUSIONS When residual bone height over the mandibular canal is between 7 and 8 mm, 7 mm short implants might be a preferable choice than vertical augmentation, reducing the chair time, expenses and morbidity. These 1-year preliminary results need to be confirmed by follow-up of at least 5 years.

Inlay versus Onlay Iliac Bone Grafting in Atrophic Posterior Mandible: A Prospective Controlled Clinical Trial for the Comparison of Two Techniques

PURPOSE To compare the efficacy of inlay and onlay bone grafting techniques in terms of vertical bone formation and implant outcomes for correcting atrophic posterior mandibles. MATERIALS AND METHODS Twenty surgical sites were assigned to two treatment groups, inlay and onlay, with iliac crest as donor site. After 3 to 4 months, 43 implants were placed and loaded 4 months later. The median follow up after loading was 18 months. RESULTS For the inlay versus onlay group, median bone gain was 4.9 versus 6.5 mm (p = .019), median bone resorption was 0.5 versus 2.75 mm (p < .001), and median final vertical augmentation was 4.1 versus 4 mm (p = .190). The implant survival rate was 100% in both groups, while the implant success rate was 90% versus 86.9% (p = .190, not significant). A minor and major complication rate of 20% and 10%, respectively, for both groups was encountered. CONCLUSIONS Inlay results in less bone resorption and more predictable outcomes, but requires an experienced surgeon. In contrast, onlay results in greater bone resorption and requires a bone block graft oversized in height, but involves a shorter learning curve. Once implant placement has been carried out, the outcomes are similar for both procedures.

Five-year outcome of 111 immediate nonfunctional single restorations.

Immediate loading is a surgical-prosthetic procedure extensively used in implant dentistry. Despite its frequent use, minimal data are available on the long-term clinical success rate of immediate functional loading (IFL) and immediate nonfunctional loading (INFL) of implants. The aim of this study was to evaluate the long-term survival and bone loss of immediate nonfunctional single implant restorations in a group of patients that were monitored for 5 years. One hundred and eleven patients (41.4% men) with a median age of 40 years were included in this study. A total of 111 implants were placed. All implants were placed with a minimum insertion torque of 25 Ncm. A temporary restoration was relined with acrylic resin, trimmed, polished, and cemented or screw-retained 1 to 2 hours later. Occlusal contact was avoided in centric and lateral excursions. After provisional crown delivery, a periapical radiograph was performed by means of a customized Rinn holder device. Data were analyzed by means of Kaplan-Meier and life-table algorithms. Stratification of implant survival was performed for the available variables of interest, and comparisons were analyzed using a log-rank test. Investigated parameters were time of implant placement, bone quality, implant site, implant diameter and length, and type of implant surface enhancement. The parameters for overall success rate were defined by bone resorption <1.5 mm after the first year of loading and <0.2 mm thereafter. During the 5-year follow-up period, a survival rate of 95.5% was observed. All failures occurred within 4 months of implant loading. There were statistically significant differences regarding healed vs post-extraction implant sites (100% and 92.5%, respectively, P = .05) and type of bone (D1 vs D4 yielded 100% and 95.5%, respectively, P <.05). No differences were detected for: (1) site (100% for mandible and 94.63% for maxilla, P =-.319); (2) implant diameter (survival rates of 97.26% for <4.5-mm diameter and 92.11% for >4.5mm diameter, P = .206); (3) implant lengths (survival rates of 96.97% for implants >13 mm and 94.87% for implants <13 mm, P =.624); and (4) type of implant surface enhancement (survival rates of 94.03% for 67 cases of grit-blasted and acid-etched surfaces and a failure rate of 4 out of 5, and 94.12% for 17 cases of hydroxyapatite (HA)-coated surfaces with only 1 failure). The success rate (defined as bone resorption >1.5 mm after the first year of loading and >0.2 mm thereafter) was 97.2%. Immediate nonocclusal loading of single implants is a reliable surgical-prosthetic procedure with a low rate of implant loss and a low quantity of peri-implant bone loss over time.

Reconstruction of Atrophied Posterior Mandible With Inlay Technique and Mandibular Ramus Block Graft for Implant Prosthetic Rehabilitation

PURPOSE To describe a successful clinical case of implant prosthetic rehabilitation in an atrophic posterior mandible reconstructed by inlay bone grafting after bone block harvesting from the mandibular ramus. PATIENTS AND METHODS A 55-year-old woman with an atrophied right posterior mandible underwent surgical inlay ridge augmentation under local anaesthesia using a block graft harvested from the ipsilateral mandibular ramus. Three months later 3 dental implants were inserted, and after an additional 4 months abutments were connected and a definitive fixed bridge inserted. RESULTS After a 24-month follow-up, no implant failure was recorded; the patient was functionally and esthetically satisfied. CONCLUSION The inlay procedure in atrophic posterior mandible, associated with mandibular ramus graft harvesting, may be considered an effective, minimally invasive and well-tolerated procedure for implant prosthetic rehabilitation.

Clinical-radiographic and histological evaluation of two hydroxyapatites in human extraction sockets: a pilot study

After tooth extraction the healing process involves bone resorption and soft tissue contraction, events that can compromise the ideal implant placement with functional and aesthetic limitations. Following tooth extraction, a socket preservation technique can limit bone resorption. This study evaluated two different types of hydroxyapatite (HA) grafting materials placed into fresh extraction sockets, 6 months after tooth extraction, histologically, clinically and radiographically. Ten extraction sockets from 10 patients were divided in two groups: 5 sockets received a biomimetic HA and 5 received nanocrystalline HA. After 6 months, before implant placement, samples from the grafted area were harvested and evaluated clinically, radiographically and histologically. The percentages of bone, osteoid areas and residual material in the two groups were not statistically different. All samples showed great variability with extensive bone formation and total material resorption or amounts of osteoid tissue that filled the spaces between the residual material particles. The authors did not find any differences between biomimetic and nanocrystalline HA and assume that, within the limits of this study, both these materials could be applied into fresh extraction sockets to limit bone resorption. A control material and a much larger sample size are needed to confirm these findings.

Implant prosthetic rehabilitation of posterior mandible after tumor ablation with inferior alveolar nerve mobilization and inlay bone grafting: a case report.

PURPOSE To report a successful clinical case of dental implant provisionalization of a posterior mandible resected for tumor ablation and subsequently reconstructed with interpositional bone grafting after mobilization of the inferior alveolar nerve. MATERIALS AND METHODS A 47-year-old woman with a severe posterior mandibular defect due to ablation of a squamous cell carcinoma was treated with transposition of the inferior alveolar nerve and inlay iliac bone graft. Four months later, 4 dental implants were inserted and immediately provisionalized. Bone core biopsies were taken during implant insertion. After an additional 3 months, a definitive fixed bridge was inserted. RESULTS At the 24-month follow-up visit, all implants appeared to have osseointegrated. The histologic examination showed that the grafted bone was lined by newly formed bone without gaps at the interface. CONCLUSIONS Inlay bone grafting can allow implant provisonalization of the posterior mandible even with a remarkable bone alveolar deficit after tumor ablation.

Le Fort I Osteotomy With Interpositional Graft and Immediate Loading of Delayed Modified SLActive Surface Dental Implants for Rehabilitation of Extremely Atrophied Maxilla: A Case Report

PURPOSE To describe a successful clinical case of immediate prosthetic loading of modified sandblasting and acid-etching surface ITI dental implants inserted in a grafted maxilla after Le Fort I osteotomy. MATERIALS AND METHODS A 59-year-old man with a severely atrophied maxilla was treated with Le Fort I osteotomy and interpositional iliac bone graft. Thirteen weeks later, 7 modified sandblasted and acid-etched surface ITI dental implants were inserted with immediate application of a screw-fixed prosthetic acrylic device kept in functional loading for 3 months until a definitive fixed prosthesis was inserted. RESULTS After 20-month follow-up there has been no implant failure, with minimal bone loss and healthy peri-implant soft tissues; the patient is functionally and esthetically satisfied. CONCLUSIONS Immediate loading of implants placed after Le Fort I osteotomy and interpositional iliac bone grafting could be an applicable protocol to rehabilitate extremely atrophied edentulous maxillas.