Stability, marginal bone loss and survival of standard and modified sand-blasted, acid-etched implants in bilateral edentulous spaces: a prospective 15-month evaluation

Objectives: Chemical modification of the already proven sand-blasted and acid-etched (SLA) implant had increased its surface wettability and consequent early-term osseointegration characteristics. The aim of this clinical trial was to compare the stability changes, success, survival, peri-implant parameters and marginal bone loss (MBL) of the early-loaded standard (SLA) and modified sand-blasted, acid-etched (modSLA) implants. Material and methods: A total of 96 SLA and modSLA implants were placed in a bi-lateral, cross-arch position to the jaws of 22 patients. Resonance frequency analysis (RFA) was used to measure the implant stability in the surgery and following healing after 1, 3 and 6 weeks. At the stage of loading, a panoramic X-ray was obtained and RFA measurement was repeated for all implants. Implants were restored by metal-ceramic crowns and followed for 1 year to determine the success, survival rate, peri-implant parameters and MBL. Results were compared by one-and two-way ANOVA, log-rank test and generalized linear mixed models (P<0.05). Results: One modSLA implant was lost after 3 weeks following the surgery yielding to a 100 and 97.91% success rate for SLA and modSLA implants, respectively (P = 0.323). At the loading stage, modSLA implants showed significantly lower MBL (0.18 +/- 0.05 mm) than SLA implants (0.22 +/- 0.06 mm; P = 0.002). In the loading stage, RFA value of the modSLA implants (60.42 +/- 6.82) was significantly higher than the both implant types in the surgical stage (55.46 +/- 8.29 and 56.68 +/- 8.19), and following 1 (56.08 +/- 7.01 and 55.60 +/- 9.07) and 3 weeks of healing (55.94 +/- 5.95 and 55.40 +/- 6.50 for SLA and modSLA implants, respectively). Conclusions: modSLA implants demonstrated a better stability and a reduced MBL at the loading stage. Both SLA and modSLA implants demonstrated a favorable success and survival at the end of 15-month follow-up.