Hybrid Funnel Technique Reduces Marginal Bone Loss Versus Conventional Drilling: A 3-Year, Prospective, Non-randomized, Controlled Clinical Trial.

PURPOSE: This study aimed to compare marginal bone loss (MBL) associated with Hybrid Funnel Technique (HFT) and conventional drill osteotomy for implant site preparation when bioactive implants are used, testing the null hypothesis that no significant differences occur at 1- and 3 years.

MATERIALS AND

METHODS

This prospective non-randomized controlled clinical trial included patients undergoing implant rehabilitation with bioactive-surface implants. Implants were placed using either conventional subtractive drilling (control group) or HFT (test group), which combines selective cortical preparation with medullary osteocompaction. The primary outcome was radiographic MBL at 3-year follow-up. Secondary outcomes included bleeding on probing (BoP) and plaque index (PI). Statistical analyses were performed at implant level, and linear mixed-effects models were used to account for clustering within patients and adjust for potential confounders.

RESULTS

A total of 87 implants in 43 patients were analyzed (42 control, 45 HFT). At 1-year follow-up, the test group reported significantly lower MBL (0.33 ± 0.43 mm vs. mean = 0.78 ± 0.82 mm; Mann-Whitney p-value = 0.006). At 3 years, MBL was significantly higher in the conventional site preparation group compared with the HFT group (1.34 ± 0.79 mm vs. 0.46 ± 0.69 mm; p < 0.001). In multivariate mixed-effects analysis, the implant site preparation technique was the only variable independently associated with MBL at 3 years (β = -1.10 mm, 95% CI = -1.675 to -0.527, p < 0.001), while insertion torque and other baseline variables showed no significant association. In addition, the HFT group demonstrated significantly lower BoP and PI scores, indicating more favorable peri-implant soft tissue conditions.

CONCLUSIONS

Despite the use of identical bioactive-surface implants, implant site preparation technique significantly influenced peri-implant bone remodeling. HFT demonstrated superior preservation of marginal bone over 3 years, suggesting that reduction of cortical compression during osteotomy provides a biological advantage. Implant site preparation remains a key determinant of long-term peri-implant bone stability.