Excessive occlusal load on chemically modified and moderately rough titanium implants restored with cantilever reconstructions. An experimental study in dogs

Objective: To evaluate the outcomes of excessively loaded implants. Material and Methods: In five dogs, all mandibular premolars were extracted. After 3 months, six implants (three SLA® and three SLActive®) were placed (S). After 4 weeks, implants were restored: one single crown with stable occlusal contacts (SC), one crown and a cantilever unit with excessive occlusal contacts (OL), and a non-loaded implant (NL). Bleeding-on-probing (BoP), attachment level (AL), mucosal margin (GM) were assessed. Resonance frequency analysis (RFA) was assessed weekly. Standardized X-rays were taken at S, 4 and 24 weeks. Results: Similar findings were observed for SLA® and SLActive® implants regarding PlI, GI, GM, AL, and BL. No significant differences were detected between baseline and 24-weeks or between treatment modalities for all clinical parameters (p >.05). Six months after loading, RFA values were significantly greater than at implant placement. No significant differences between treatment modalities were found. Linear radiographic measurements yielded similar results between SLA® and SLActive® implants. SLA® OL implants yielded a statistically significant gain on peri-implant bone density over all other groups (p =.012). Radiographic results were confirmed by descriptive histology. Technically, loosened occlusal screws occurred in 13.3% (SC = 3.3%; OL = 10%), while abutment fractures totalized 23.3% (SC = 6.6%; OL = 16.6%). Conclusions: Excessive occlusal load applied to implants (SLA® or SLActive®) restored with cantilevers did not cause loss of osseointegration or significant changes in their clinical, radiographic, or histologic outcomes. Early excessive occlusal load on SLA® implants promoted a gain in peri-implant bone density. Excessively loaded implants showed more technical complications.