A 3-year prospective cohort study on 132 calcium phosphate-blasted implants: flap vs flapless technique

Purpose: To evaluate the survival rate and marginal bone loss (MBL) of a calcium phosphate-blasted titanium implant inserted by a flap or flapless technique and to study the morphochemical characteristics of the implant surface. Materials and Methods: Sixty out of 85 patients who received one or more implants were selected as eligible for this prospective longitudinal cohort clinical study. Titanium implants (n = 132) were placed in human healthy subjects using either a flap or flapless technique, selected on the basis of the best practice. The survival rate and MBL were evaluated after 3 months (preloading stress-free healing period) and after 6, 12, 24, and 36 months in relation to implant diameter, location, sex, and smoking habits. Surface morphochemical analyses were performed by environmental scanning electron microscopy connected with energy-dispersive x-ray (ESEM/EDX). Results: The overall survival rate was 97.72%. After 3 and 36 months, MBL was 0.36 ± 0.66 mm and 1.09 ± 1.10 mm for the flapless group and 0.29 ± 0.51 mm and 1.03 ± 0.92 mm for the flap group. MBL showed a statistically significant increase with time (P = .0001), and differences were found at all times since 6 months. No statistical differences between the flapless and flap groups and sex were observed at any time, while MBL was significantly higher in the maxillary versus mandibular location (6, 12, and 24 months) and in smokers versus nonsmokers (6 months). Higher MBL in both groups was found for a smaller diameter (3.5 mm) than larger diameter (4.1, 5 mm). The surface showed a Ti-Al-V alloy displaying a uniform nanotexture. Conclusion: The implant system showed a high survival rate and markedly lower MBL considering the limits for acceptable progression. Flapless and flap techniques demonstrated similar results of MBL at the preloading healing period and at the 6 months to 3 years postloading periods. Both surgical procedures induced an early MBL during the preloading stress-free period. Implant diameter, mandibular/ maxillary location, preloading stress-free period, and smoking habits affect MBL more than the type of surgery after both short- and long-term follow-up.