Clinical and histologic evaluation of healing following tooth extraction with ridge preservation technique using a xenograft protocol in aesthetics sites

reabsorption of the alveolar ridge with quantitative and qualitative changes of its profile that tends to decrease and results in the disappearance of bundle bone. To modify bone remodelling after extraction, especially in absence of the vestibular bone wall, various ridge preservation techniques have been proposed. The objective of this study was to evaluate and to compare changes of hard and soft tissues in post-extraction sockets and histologically quantify the alveolar ridge preservation after tooth extraction using a new surgical protocol. Methods: Ten subjects who required tooth extraction and implant placement in an aesthetic site were enrolled in this study. All subjects presented, at the end of the tooth extraction, different level of defects in the buccal bone. The buccal wall was subsequently remodelled to create a standardized defect, 4 mm wide coronally, 2 mm wide apically, and 6 mm high. deproteinized bovine bone mineral (DBBM) xenograft granules were used to fill the defects. All surgical sites were subsequently covered vestibular by with a resorbable membrane composed of 90% anorganic bovine bone in combination with 10% porcine collagen fibers and, occlusal, with a resorbable 3D collagen matrix membrane and a non-submerged healing was obtained. Following 14 weeks of healing, clinical measurements as horizontal ridge width, vertical ridge changes and width of keratinized gingiva were recorded and a core biopsy was obtained and prepared for histologic evaluation of percentages of vital bone, residual graft, and soft tissues assessment in each patient. Results: At 14 weeks, the mean horizontal ridge width at the buccal crest decreased from 8.2 ± 1.1 to 7.8 - 1.2 mm for a mean loss of 0.4 ± 0.8 mm (P>0.05) and the vertical change at the lingual sites was 0.5 mm respect to baseline; the keratinized gingiva showed a coronal shift of 1.2 mm. In addition, only 14% of sites required an additional bone augmentation at implant placement. The biopsies harvested from the grafted sites revealed the presence of trabecular bone, which was highly mineralized and well structured. Particles of the grafted material could be identified in 71% of the samples in the treated subjects and the bone formed in the sites was also well structured with a minor percentage of mineralized bone. The amount of connective tissue was significantly higher. Conclusions: The use of xenograft particles concomitantly with the application of two different collagen membranes used for the vertical ridge preservation approach immediately after tooth extraction contributed to the preservation of the alveolar process. Furthermore, the histologic analysis showed that the porcine-derived xenograft particles were not resorbed but became surrounded by new bone and that was present a significantly higher percentage of trabecular bone and total mineralized tissue in ridge-preservation sites 14 weeks after tooth