Biologics and cell therapy tissue engineering approaches for the management of the edentulous maxilla: a systematic review

Purpose: The aim of this systematic review was to evaluate current and emerging regenerative approaches for implant site development in the edentulous atrophic maxilla using tissue engineering and regenerative medicine (TERM) principles and to identify priorities for future research. Materials and Methods: Two independent examiners conducted a comprehensive search using specific keywords to identify original clinical studies using TERM for implant site development in the edentulous atrophic maxilla including indications for alveolar ridge preservation, horizontal alveolar augmentation, maxillary sinus augmentation, and augmentation of severe vertical or combined defects. Endpoints included clinical, radiographic, histologic, and patient-centered outcomes. Results: The initial search identified 3,061 articles. The final selection included 89 articles, of which 12 evaluated alveolar ridge preservation, 6 horizontal defects, 61 maxillary sinus augmentation, and 11 management of severe vertical or combined defects. A summary of the main findings relative to the effect of TERM-based approaches applied for implant site development in the atrophic maxillary segments is presented. Marked heterogeneity among included studies prevented meaningful quantitative analysis. The following relevant effects of TERM-based therapies for site development in the edentulous atrophic maxilla were observed: (1) recombinant human bone morphogenetic protein-2 in an absorbable collagen sponge carrier increased bone augmentation; (2) recombinant human platelet-derived growth factor BB in combination with freeze-dried bone allograft or beta tricalcium phosphate accelerated bone formation through accelerated remodeling of carrier biomaterials; (3) autologous cell therapy enhanced clinical and radiographic outcomes; (4) autologous cell therapy in alveolar ridge preservation provided superior histomorphometric outcomes (vital bone formation) at 6 weeks; and (5) platelet-rich plasma formulations combined with autologous bone grafts for maxillary sinus augmentation increased radiographic density and accelerated bone mineralization at 6 months. Conclusion: Clinical success has been demonstrated with the application of different TERM modalities for implant site development in the edentulous atrophic maxilla. However, indications are narrow and further study is needed. Clinical trials assessing meaningful outcomes, involving larger populations, and with longer follow-up are warranted to discern the effectiveness of the achieved results compared with a valid control.Gustavo Avila-Ortiz, P. Mark Bartold, William Giannobile, Wataru Katagiri, Salvador Nares, Hector Rios, Daniel Spagnoli, Ulf M.E. Wikesj

The Effect of Suturing Protocols on Coronally Advanced Flap Root-Coverage Outcomes: A Meta-Analysis

The purpose of this systematic review and meta-analysis was to investigate whether suturing protocols (suture removal timing and/or type of suture material) influence root coverage outcomes in recession defects treated with a coronally advanced flap (CAF) procedure. Databases (MEDLINE, EMBASE) were searched for randomized clinical trials (RCTs) that assessed single-tooth, Miller Class I/II recession defects, surgically treated by CAF. Mixed-effects linear regression analysis evaluated differences on complete root coverage (CRC) between RCTs with early (<10 days postoperatively) and late (≥10 days) suture removal, as well as between RCTs using absorbable and non-absorbable sutures removed ≥10 days postoperatively. Seventeen RCTs were eligible for inclusion. Overall, data from 325 single gingival recession defects revealed a statistically significant superior proportion of sites exhibiting CRC when sutures were removed ≥10 days postoperatively compared to those in which sutures were removed <10 days (P = 0.03). Conversely, there were no significant differences in CRC outcomes between absorbable and non-absorbable sutures when they were removed ≥10 days after surgery (P = 1.00). The majority of included RCTs (59%) reported use of non-absorbable suture materials. Within the limitations of the available data, it can be concluded that early suture removal (<10 days) can negatively influence root-coverage outcomes in single-tooth defects treated by a CAF procedure. There is a strong need for studies designed specifically to investigate suturing protocols in root-coverage procedures