The effect of a flapless alveolar ridge preservation procedure with or without a xenograft on buccal bone crest remodeling compared by histomorphometric and microcomputed tomographic analysis.

OBJECTIVES: This study evaluated buccal bone crest remodeling, socket composition after healing, and dimensional ridge preservation after flapless tooth extraction procedures with or without a xenograft comparing histomorphometric and microcomputed tomographic (micro-CT) data. MATERIAL AND METHODS: The mandibular premolars of eight dogs were extracted without flaps. One socket on each side received a grafting material (test group), and the other remained only with a blood clot (control group). Twelve weeks after treatment, buccal bone crest, alveolar ridge dimensions, and composition were analyzed by histomorphometry and micro-CT. RESULTS: Two- and three-dimensional evaluations showed better results for the grafted group when compared to the non-grafted group. CONCLUSION: The flapless alveolar ridge preservation procedure with deproteinized bovine bone material enhanced buccal bone crest, alveolar ridge dimensions and bone formation when compared to sockets with the blood clot only, as observed by histomorphometric and micro-CT analysis.

Early peri-implant endosseous healing of two implant surfaces placed in surgically created circumferential defects. A histomorphometric and fluorescence study in dogs.

OBJECTIVE: Several implant surfaces are being developed, some in the nanoscale level. In this study, two different surfaces had their early healing properties compared in context of circumferential defects of various widths. MATERIAL AND METHODS: Six dogs had the mandibular premolars extracted. After 8 weeks, four implants were placed equicrestally in each side. One acted as control, while the others were inserted into sites with circumferential defects of 1.0, 1.5 and 2.0 mm wide and 5 mm deep. A nano-modified surface was used on one side and a micro-rough on the other. Bone markers were administered on the third day after implant placement and then after 1, 2, 4 weeks to investigate the bone formation dynamic through fluorescence analysis. Ground sections were prepared from 8-week healing biopsies and histomorphometry was performed. RESULTS: The fluorescence evaluation of the early healing showed numerically better results for the nano-modified group; however this trend was not followed by the histomorphometric evaluation. A non-significant numerical superiority of the micro-rough group was observed in terms of vertical bone apposition, defect bone fill, bone-to-implant contact and bone density. In the intra-group analysis, the wider defects showed the worse results while the control sites showed the best results for the different parameters, but without statistical relevance. CONCLUSION: Both surfaces may lead to complete fill of circumferential defects, but the gap width has to be considered as a challenge. The nano-scale modification was beneficial in the early stages of bone healing, but the micro-rough surface showed numerical better outcomes at the 8-week final period.

Acellular dermal matrix allograft. The results of controlled randomized clinical studies.

The aim of this presentation was to discuss the effectiveness of the acellular dermal matrix in root coverage therapy and in alveolar ridge augmentation, based on three controlled randomized clinical trials conducted by our research team (Novaes Jr et al., 2001; Barros et al., 2005; Luczyszyn et al., 2005). The first and second studies highlight the allograft's performance in the treatment of gingival recession. In both studies, clinical parameters were assessed prior to surgery and 6 or 12 months post-surgery. The first one compared the use of the acellular dermal matrix with the subepithelial connective tissue graft and showed 1.83 and 2.10 mm of recession reduction, respectively. Because no statistically significant differences between the groups were observed, it was concluded that the allograft can be used as a substitute for the autograft. In the second study, a new surgical approach was compared to a conventional surgical procedure described by Langer and Langer in 1985. A statistically significant greater recession reduction favoring the test procedure was achieved. The percentage of root coverage was 82.5% and 62.3% for test and control groups. Thus the new technique was considered more suitable for the treatment of gingival recessions with the allograft. Finally, the third study evaluated the allograft as a membrane, associated or not with a resorbable hydroxyapatite in bone regeneration to prevent ridge deformities. In one group the extraction sockets were covered only by the allograft and in the other, the alveoli were also filled with the resorbable hydroxyapatite. After six months, both treatments were able to preserve ridge thickness, considering the pre-operative values. In conclusion, no adverse healing events were noted with the use of allograft in site preservation procedures, and sites treated with the combination of allograft plus resorbable hydroxyapatite showed significantly greater ridge thickness preservation at six months when compared to sites treated with allograft alone (6.8 +/- 1.26 and 5.53 +/- 1.06 respectively).

Influence of implant surfaces on osseointegration.

The biological fixation between the dental implant surfaces and jaw bones should be considered a prerequisite for the long-term success of implant-supported prostheses. In this context, the implant surface modifications gained an important and decisive place in implant research over the last years. As the most investigated topic in, it aided the development of enhanced dental treatment modalities and the expansion of dental implant use. Nowadays, a large number of implant types with a great variety of surface properties and other features are commercially available and have to be treated with caution. Although surface modifications have been shown to enhance osseointegration at early implantation times, for example, the clinician should look for research evidence before selecting a dental implant for a specific use. This paper reviews the literature on dental implant surfaces by assessing in vitro and in vivo studies to show the current perspective of implant development. The review comprises quantitative and qualitative results on the analysis of bone-implant interface using micro and nano implant surface topographies. Furthermore, the perspective of incorporating biomimetic molecules (e.g.: peptides and bone morphogenetic proteins) to the implant surface and their effects on bone formation and remodeling around implants are discussed.