Correction of Buccal Dehiscence During Immediate Implant Placement Using the Flapless Technique: A Tomographic Evaluation

• Autores: Jamal Hassan Assaf, Débora do Canto Assaf, Raquel Pippi Antoniazzi, Leandro Berni Osório, Fabiana Mantovani Gomes França
• Localización: Journal of periodontology, ISSN 0022-3492, Vol. 88, Nº. 2, 2017, págs. 173-180
• Idioma: inglés
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• Resumen

  • Background: The aim of this study was to evaluate a new technique for treating dehiscence buccal bone sites (Class II) with immediate implant and collagen-enriched bovine-derived xenograft blocks without a surgical flap or membrane.

    Methods: Individuals with at least 5 mm of buccal bone dehiscence were selected for a flapless surgical approach to insert xenograft blocks into buccal dehiscence defects as well as the gap between implant and residual bone wall. No membrane was used. Buccal bone wall height was measured by computed tomography in the preoperative period (T0) and 6 to 12 months after procedure (T1). Likewise, buccal-lingual width of alveolar ridge as well as thickness of buccal wall was compared with the contralateral tooth.

    Results: Fourteen patients were selected. Buccal wall height at T1 was not significantly different after 6 to 12 months between the treated and contralateral teeth, although both were greater than T0 (P <0.01). The heights ranged from 6.4 to 16.30 mm at T0, 12.8 to 25.6 mm at T1, and 14.8 to 25.29 mm in the contralateral teeth. Significant differences were observed between treated teeth (T1) and their contralateral, both buccal-lingually in the alveolar ridge (P = 0.007) and in buccal wall thickness (P = 0.003). Wall thickness ranged from 0.9 mm to 3.81 mm at T1 and 0.25 mm to 1.60 mm in the contralateral teeth.

    Conclusion: Immediate implant placement at dehiscence buccal bone sites using flapless surgery combined with xenograft blocks provided complete formation of the buccal bone wall up to the implant shoulder.

    Resorption of alveolar bone walls is a consequence of tooth extraction, particularly in the buccal wall,1 regardless whether a surgical flap was raised.2-4 Studies in humans using lyophilized bone, autogenous bone, xenogeneic bone grafts, and synthetic bone substitute have been performed with the aim of preserving alveolar dimensions following tooth extraction, revealing that such approaches were able to partially preserve alveolar ridge dimensions after healing.5-7 Evidence from animal models has also shown that use of collagen-enriched bovine-derived xenograft blocks in extraction sockets resulted in reduction in alveolar dimension loss when compared with non-grafted sites.8,9 Immediate implant placement does not prevent loss of alveolar dimensions1,10-12 and, for that reason, alternative treatment approaches to preserve alveolar dimensions during immediate implant placement have been investigated.13,14 Use of biomaterials in the gap between implant and buccal bone wall aims to minimize bone resorption at the implant site.13 Several studies have reported lower resorption of buccal bone walls when using biomaterials.14-17 Such studies have evaluated extraction sockets and immediate implants at sites with intact bone walls, but little is known with regard to sockets that feature buccal bone loss. In an animal model study, it was observed that healing of buccal bone defects after extraction had a distinctive pattern when compared with sockets with intact walls, where the former showed greater dimension loss.18 Use of immediate implants at sites with Class II and III bony dehiscence defects19 is usually accompanied by guided bone regeneration (GBR), where a surgical flap is necessary, as well as use of biomaterials or autologous or allogenic bone and a membrane.20 GBR allows the surgical site to be colonized by bone tissue cells surrounding the regeneration area and re-establishment of local bone volume.19,21 Studies involving dehiscence implant sites have also investigated grafts without a membrane and reported similar results to those in which a membrane was used.17,22-25 In Class II dehiscence defects, in which volume stability is achieved by the adjacent bone walls in combination with an implant placed within the confines of the bony defect, partial regeneration of the defect occurs even without use of regenerative techniques.17,23,26 In spite of such gain being only partial, this fact alone demonstrates the excellent regenerating potential of this type of defect.

    The literature, however, is scarce on regenerative approaches that feature simple procedures. Therefore, the aim of this study was to evaluate a new technique for treating dehiscence buccal bone sites (Class II) with immediate implant and collagen-enriched bovine-derived xenograft blocks without a surgical flap or membrane.