Early volumetric changes after vertical augmentation of the atrophic posterior mandible with interpositional block graft versus onlay bone graft: A retrospective radiological study.

PURPOSE: The aim of this study was to evaluate volumetric and clinical outcomes of atrophic posterior mandibles treated with inlay or onlay bone grafting techniques. MATERIALS AND METHODS: In posterior mandibles, alveolar ridges were treated either with interpositional equine cancellous bone block (inlay group) or with onlay autogenous bone block (onlay group). Bone volumes at baseline and at 4 months after surgery were measured by computed tomography. RESULTS: A total of 20 subjects were enrolled in the present study: 10 in the inlay group and 10 in the onlay group. After surgery, atrophic posterior mandibles showed a mean vertical augmentation height of 6.0 mm in the inlay group and 7.4 mm in the onlay group. No significant differences were recorded between the two groups regarding volume loss of the grafted bone or decrease in vertical bone height of the augmented site (29% and 1.9 mm for the onlay group, and 35% and 1.7 mm for the inlay group) during healing. Two complications (1 wound dehiscence and 1 mandibular fracture) occurred postoperatively in the inlay group; on the other hand, the onlay group had three complications (wound dehiscence). A total of 80 dental implants were placed in augmented areas: 46 in the inlay group with a peri-implant marginal bone loss of 0.8 mm, and 34 in the onlay group with a peri-implant marginal bone loss of 1.3 mm (p = 0.0006). CONCLUSIONS: Inlay xenogeneic grafts showed volumetric bone remodeling similar to that recorded for onlay autogenous bone. The success of the autogenous onlay blocks (82.4%) appeared to be lower than that registered for the inlay group (93.8%), but the difference was not significant.

Extra oral digital scanning and imaging superimposition for volume analysis of bone remodeling after tooth extraction with and without 2 types of particulate porcine mineral insertion: A randomized controlled trial.

BACKGROUND: Incorporation of bone substitute material into the extraction socket could minimize the edentulous ridge volume loss or maximize the bone formation within the healing area. PURPOSE: The aim of the study was to test the effectiveness in maintaining the volumetric contour of fresh extraction sockets grafted with or without 2 types of porcine biomaterials and covered with a resorbable barrier. MATERIALS AND METHODS: In the present multi-center single-blind randomized control trial, 55 patients underwent 1-tooth extraction, were surveyed, and randomly allocated to control- (25 sites, nat-group) or test groups (15 sites grafted with pre-hydrated collagenated cortico-cancellous porcine bone, coll-group, and 15 with cortical porcine bone, cort-group). Before extraction, and then 4 months later, contours of the sockets were acquired through a laser scanner, voxelized, and ghosts of each patient were superimposed with a matrix laboratory. Volumetric and area evaluations of the virtual superimposed models were performed with dentascan tools to create a volume of interest extending between the 2 residual teeth. Intra- and inter-group comparisons of the outcomes were performed. Non-parametric tests were applied with a level of significance set at P < .05. RESULTS: Intergroup analysis at 4 months' survey revealed that percentage loss of alveolar ridge volume of the coll-group (28.8% ± 8.8%) and of the cort-group (30.2% ± 7.1%) was significantly lower (P < .0001) than that of the naturally-healing group (46.4% ± 4.1%). No statistically-significant differences in outcomes were observed between the 2 test groups at any of the observation periods. Moreover, tooth position (bicuspids vs molars) seemed to affect neither volume loss nor basal shrinkage. CONCLUSION: At the 4-month analysis both test groups showed reduced bone loss when compared to naturally healing sockets. However, the 2 grafting materials were not able to preserve the alveolar crest, and a reduction close to 30% in the estimates was registered after healing.

Gene clustering analysis in human osseous remodeling.

BACKGROUND: Tentative bioinformatic predictions were performed to comprehend the complexity of the gene interaction networks of the T lymphocyte cell cycle and of human periodontitis. This study aims to identify and rank genes involved in osseous augmentation or bone remodeling to obtain groups with more numerous predicted associations called the leader gene clusters. METHODS: An iterative search (consisting of a consecutive expansion-filtering loop) was performed for which only genes involved in a specific process were identified. For each gene, predicted associations with all other involved genes were obtained from a Web-available database (Search Tool for the Retrieval of Interacting Genes/Proteins) and the weighted number of links (WNL), given by the sum of only high-confidence predicted associations (results with a score > or =0.9), allowing gene ranking. Genes belonging to higher clustering classes were identified. RESULTS: A total of 161 genes potentially involved in bone-volume augmentation and 128 genes connected with the bone-remodeling phenomenon were identified. For the bone-volume augmentation process, only one gene belonged to the leader gene group, whereas six other genes were classified as cluster B genes; for the bone-remodeling phenomenon, three leader genes were identified, whereas six other genes formed the cluster B group. No one gene belonged to leader gene clusters of both processes, whereas one gene of each higher cluster group belonged to the immediately lower cluster of the opposite process. Only three genes of the higher clusters were experimentally involved in both analyses. CONCLUSIONS: A de novo identification was performed based on the data mining of leader genes involved in bone-volume augmentation or bone remodeling to acquire primeval information about their molecular basis and to plan future ad hoc targeted experiments. For several genes of the upper clusters, an active role in the bone processes was already known, but the present analysis suggested that they play a major role in the analyzed phenomena. The role of the transcription factors as leader genes and the numerous orphan genes (genes with WNL = 0) recovered probably attest to a lack of information regarding these processes, which could be further clarified through specific DNA microarray experiments.

Implant survival in maxillary and mandibular osseous onlay grafts and native bone: a 3-year clinical and computerized tomographic follow-up.

PURPOSE: This article discusses a 3-year retrospective survey of implant clinical survival and computerized tomographic analysis of bone remodeling in atrophic alveolar crests reconstructed via various autogenous bone grafting procedures and in similar regions of native bone. MATERIALS AND METHODS: The retrospective chart review included consecutive edentulous patients with severe alveolar crest atrophy treated between 2000 and 2002 with onlay autogenous bone grafts in the mandible and anterior maxilla (as needed) and implant insertion. Implant recipients were followed for 3 years. Defective areas were reconstructed by bone graft harvested from the chin or iliac crest. Implants in reconstructed areas were divided into two groups according to graft source. Implants in corresponding native areas served as controls. Cumulative survival rate (CSR), survival rate, and confidence interval (CI) were calculated, and linear measurements of bone remodeling around implants were assessed on computerized tomographic scans. Results were compared for statistically significant differences by Wilcoxon signed-rank test with a significance level a = .05. RESULTS: Forty patients were treated with 109 screw-type, root-form, rough-surfaced implants inserted in 48 onlay grafts; 88 implants were placed in native bone. The implant 3-year CSRs were 98.9% (CI 96.7% to 100%) in native bone and 99.1% (CI 97.3% to 100%) in onlay grafts, irrespective of bone source. Mean resorption in the maxilla was 4.6 +/- 0.9 mm buccally and 3.8 +/- 0.8 mm palatally in areas reconstructed with chin grafts, 3.4 +/- 1.7 mm buccally and 2.6 +/- 1.4 mm palatally in areas reconstructed with iliac crest grafts, and 3.2 +/- 1.2 mm buccally and 2.1 +/- 0.9 mm palatally in native areas. CONCLUSIONS: Similar implant CSRs were seen in native and grafted sites. Maximal implant CSR was observed in onlay grafts from the chin despite more marked linear bone remodeling in this group as compared to iliac crest grafts or native bone.

Implant success in sinus-lifted maxillae and native bone: a 3-year clinical and computerized tomographic follow-up.

PURPOSE: The present study was a 3-year follow-up evaluation of implant clinical success and radiographic bone remodeling in sinus floors elevated with different autogenous bone-grafting procedures and in similar native bone regions. MATERIALS AND METHODS: This retrospective chart review examined consecutive edentulous patients with severe jaw atrophy treated between 2000 and 2002 via sinus lift, when needed, and implant insertion. Implants in sinus lift areas were divided into four groups by graft source (iliac crest, chin area) and technique (bone block, particulate). Implants positioned in native areas beneath the sinus floor served as controls. The cumulative success rate (CSR) and success rate (SR) were calculated, and linear measurements of bone remodeling around implants were assessed on computerized tomographic scans. Results were statistically compared with the Wilcoxon signed rank test. RESULTS: Twenty-eight patients were treated in the posterior maxilla via insertion of 70 screw-type, root-form, rough implants in 39 sinus-lifted areas. All surgical procedures were uneventful. Twenty-four implants were positioned in native areas beneath the sinus floor. The implant CSR was 95.8% in native areas (one failure/24 implants), 85% in sinuses lifted with particulate chin bone (three failures/20 implants), and 100% in the other three groups (eight in particulate iliac crest, 20 in chin block, and 22 in iliac crest block). Computerized tomographic scans revealed that bone remodeling around apices caused implants to bulge into the sinuses in both particulate bone graft groups. Crestal remodeling around implant necks was similar for all groups. CONCLUSIONS: The use of particulate chin bone grafts in sinus lift procedures does not seem to yield optimal outcomes. Milled iliac crest and chin bone tends to remodel around the implant apices, leading to bulging within the sinuses. Grafting sinuses with either chin or.iliac crest bone blocks yields the highest implant success rates and stable sinus floors.