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

Abstract

To evaluate the outcomes of excessively loaded implants. In five dogs, all mandibular premolars were extracted. After 3months, six implants (three SLA® and three SLActive®) were placed (S). After 4weeks, 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 24weeks. 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%). 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.