A within-subject comparison of short implants in the posterior region: retrospective study of up to 10 years

PURPOSE: This intra-patient retrospective study of up to 10 years evaluated the clinical success and risk factors of 6- and 8-mm long implants and their respective prostheses. MATERIALS AND METHODS: The sample consisted of patients treated at a Military Polyclinic dental service, who received both 6- and 8-mm long tissue level implants in the posterior region of the same arch. Data were collected from the dental charts, clinical and radiographic exams, self-report of sleep bruxism, measurement of maximum occlusal force, and clinical crown-to-implant (C/I) ratio. Data were analyzed by descriptive and inferential statistics with univariate and hierarchical multivariate models, at the 0.05 significance level. RESULTS: The 30 patients (27 women) had 85 implants and 83 prostheses. Two implants were lost before prosthesis installation (implant survival: 97.6%). Ten events of prosthetic complication (screw tightening loss) occurred in five patients (success rate: 87.9%) in a single moment. Only the variable C/I ratio had a significant effect for repairable prosthesis complication (P<.05). CONCLUSION: The results suggest that 6- and 8-mm long implants have similar long-term clinical success for implants and prostheses.