PURPOSE: To compare the time-dependent cumulative survival rates of smooth- and rough-surface dental implants. MATERIALS AND METHODS: A retrospective chart review was conducted for two time periods: January 1, 1991, through December 31, 1996, during which smooth-surface implants were used, and January 1, 2001, through December 31, 2005, during which rough-surface implants were used. This study included all implants placed and restored in one institution during the two time frames. Data were collected relative to patient age, gender, implant diameter, implant length, and anatomic location of implants. To facilitate the comparison, implants from the first and second time periods were followed through mid-1998 and mid-2007, respectively. Associations of patient/implant characteristics with implant survival were evaluated using marginal Cox proportional hazards models (adjusted for age and gender) and summarized with hazard ratios and corresponding 95% confidence intervals. RESULTS: A total of 593 patients (322 women and 271 men; mean age, 51.3 +/- 18.5 years) received 2,182 smooth-surface implants between 1991 and 1996, while 905 patients (539 women and 366 men; mean age, 48.2 +/- 17.8 years) received 2,425 rough-surface implants between 2001 and 2005. At 5 years after implant placement, survival rates were 94.0% and 94.5%, respectively, for smooth- and rough-surface implants (difference not significant). Among the smooth implants, implant length <or= 10 mm and anatomic location were identified as significantly associated with implant failure. In contrast, among the rough implants, implant length <or= 10 mm and anatomic location were not identified as risk factors for implant failure. CONCLUSIONS: Based on this retrospective study of two groups of patients with different implant surfaces and more than 2,000 implants in each group, there was no significant difference in the survival rates of smooth- and rough-surface dental implants. Anatomic location and implant length <or= 10 mm were associated with failures of the smooth-surface implants only.
PURPOSE: To compare the time-dependent cumulative survival rates of smooth- and rough-surface dental implants. MATERIALS AND METHODS: A retrospective chart review was conducted for two time periods: January 1, 1991, through December 31, 1996, during which smooth-surface implants were used, and January 1, 2001, through December 31, 2005, during which rough-surface implants were used. This study included all implants placed and restored in one institution during the two time frames. Data were collected relative to patient age, gender, implant diameter, implant length, and anatomic location of implants. To facilitate the comparison, implants from the first and second time periods were followed through mid-1998 and mid-2007, respectively. Associations of patient/implant characteristics with implant survival were evaluated using marginal Cox proportional hazards models (adjusted for age and gender) and summarized with hazard ratios and corresponding 95% confidence intervals. RESULTS: A total of 593 patients (322 women and 271 men; mean age, 51.3 +/- 18.5 years) received 2,182 smooth-surface implants between 1991 and 1996, while 905 patients (539 women and 366 men; mean age, 48.2 +/- 17.8 years) received 2,425 rough-surface implants between 2001 and 2005. At 5 years after implant placement, survival rates were 94.0% and 94.5%, respectively, for smooth- and rough-surface implants (difference not significant). Among the smooth implants, implant length <or= 10 mm and anatomic location were identified as significantly associated with implant failure. In contrast, among the rough implants, implant length <or= 10 mm and anatomic location were not identified as risk factors for implant failure. CONCLUSIONS: Based on this retrospective study of two groups of patients with different implant surfaces and more than 2,000 implants in each group, there was no significant difference in the survival rates of smooth- and rough-surface dental implants. Anatomic location and implant length <or= 10 mm were associated with failures of the smooth-surface implants only.