Aesthetic and radiographic outcomes using the root membrane technique in immediate adjacent implant placement: a retrospective clinical study with a 5- to 9-year follow-up

PURPOSE: The root membrane technique was designed to preserve the buccal portion of the root in situ, preventing postextraction bundle bone loss and overlying soft tissue recession. Nevertheless, maintenance of the aesthetic gingival architecture around two or multiple adjacent implants, particularly in the anterior maxilla, remains a challenge, notably regarding the gingival contour and the interimplant papillae. The present study aimed to evaluate the clinical, aesthetic and radiographic outcomes for immediate adjacent implants placed using the root membrane technique in the anterior maxilla in a sample with a 5- to 9-year follow-up. MATERIALS AND METHODS: A retrospective clinical study was designed using the medical records of two private dental practices. A total of 40 patients who were treated using the root membrane technique for at least two adjacent implants and single-crown restorations between January 2010 and February 2019 were selected (100 implants). The clinical and radiographic data were analysed to assess implant survival/success, marginal bone loss and the pink aesthetic score. RESULTS: The cumulative survival rate after a mean follow-up period of 81.5 ± 30.5 months was 99.0% (implant-based) and 97.5% (patient-based), respectively. Between 1 and 5 years (n = 99), the mean marginal bone loss changed from 0.39 ± 0.07 mm to 0.36 ± 0.07 mm and subsequently to 0.37 ± 0.07 mm at the 7-year follow-up (n = 71) and 0.33 ± 0.07 mm at the 9-year follow-up (n = 14). The improvement from 1 year was significant at all the follow-up time points (P = 0.000). The mean global pink aesthetic score increased from baseline (11.33 ± 1.03) to 3 months after placement of the final restoration (11.73 ± 0.95) and the final observation (12.01 ± 0.87). This was a significant increase (P = 0.000 baseline to 3 months, 3 months to final observation and baseline to final observation). CONCLUSIONS: In this non-controlled retrospective study, adjacent implants placed using the root membrane technique achieved a satisfactory survival and success rate. The variation in marginal bone loss showed a significant positive trend from 1 year to 5 and 7 years. The overall pink aesthetic scores improved significantly between sequential observation periods. CONFLICT-OF-INTEREST STATEMENT: Dr Leitão-Almeida receives personal fees (for sponsored lectures) and non-financial support from MegaGen (Daegu, South Korea) outside of the submitted work; the other authors declare no conflicts of interests relating to this study.