10-year Historical Prospective Cohort Study of Calcium Phosphate–Blasted Acid-Etched Titanium Implants Placed in Different Ridges

Purpose: To evaluate the survival rate and marginal bone level (MBL) of calcium phosphate–blasted acid-etched titanium implants placed in a cohort of patients with different ridges after a follow-up period of at least 10 years.
Materials and Methods: A total of 61 patients with a minimum implant follow-up of 10 years were selected for this historical prospective, best clinical practice cohort study. Between 2009 and 2012, 121 titanium implants were placed using a flap, flapless, or postextractive technique. The implant placement timing was performed according to pre-extractive diagnosis and divided into immediate (immediately after tooth extraction with an absence of infection), early (within 2 to 3 months with an acute periapical lesion), delayed (6 to 12 months from extraction with a large periapical infection), or late (> 12 months from extraction with healed edentulous ridges). All implants were loaded after 3 months with provisional and definitive cemented restorations. Periapical radiographs were taken before implant insertion and at 3, 6, 12, 24, 36, 48, 96, and 120 months (T3, T6, T12, T24, T36, T48, T96, and T120, respectively). The MBL was calculated in single blind by an additional examiner. Linear logistic regression was performed to analyze statistically significant differences in relation to different operative variables at all evaluation times. Multilevel mixed logistic regression was made to evaluate the factors associated to MBL at 10 years (T120).
Results: After 10 years, 47 patients and 92 implant restorations were analyzed, showing that 88 implants (95.6%) survived and 4 implants (4.4%) failed. The cumulative drop-out rate was 22.1%. Loosening and/or mobility was observed in a total of 9 abutments (9.7%) during the observational time. No other complications were reported. Implants placed with a flapless technique revealed a similar MBL to those placed with a flap technique. No significant differences were observed between the surgical techniques at T96 and T120. Immediate and early implants revealed a more stable MBL than both delayed and late implants up to T48. At longer evaluation times (T96 and T120), the MBL values were not statistically significant (P > .05). Narrower diameter implants (3.5 mm) revealed a higher bone loss when compared to the 4.1-mm– and 5.0-mm–diameters, especially in the first year from implant insertion (from T3 to T12) and at longer follow-up (T36 and T48). After that, the difference was reduced. Multilevel analysis showed that none of these variables appear to significantly influence MBL at 120 months.
Conclusions: MBL was not influenced by surgical technique or implant placement timing after 10 years. Maintaining a strict occlusal and hygiene control created the conditions to preserve bone integrity and achieve a high implant survival rate.