Biomechanical and Histologic Evaluation of Osseointegration of Titanium Dental Implants Modified by Various Combinations of Sandblasting, Acid-Etching, Hydroxyapatite, and Hyaluronic Acid Coating Techniques

Purpose: To compare the osseointegration process of the titanium dental implants with five different surface characteristics—sandblasted, sandblasted and acid-etched, hyaluronic acid–coated (HYA), hydroxyapatite-coated (HA), and machined—in an experimental sheep model at 1- and 3-month examinations.
Materials and Methods: One hundred sixty dental implants were placed in the left and right tibias of 16 sheep. Five experimental groups were designed. Eight animals (80 implants) were used for biomechanical tests of reverse torque analysis and resonance frequency analysis (RFA). Eight of them (80 implants) were used for the evaluation of bone-to-implant contact (BIC) percentage in histomorphometric analysis. Forty of 80 implants (8 implants for each group) were used at 1-month examinations, and the remaining 40 (8 implants for each group) implants were used at 3-month examinations in the biomechanical test group and histomorphometric examination group, separately.
Results: Intergroup analysis at the 3-month followup showed that the increase in the implant stability quotient (ISQ) value was statistically significant for only the HYA group (P < .05). According to ISQ values at 1 and 3 months, group HYA showed statistically higher values at the 1 and 3-month examinations (P < .05). Groups HYA and HA had statistically higher reverse torque values than other groups at the 1-month examination (P < .05). At the 3-month evaluation, the HYA group showed significantly higher reverse torque values compared to other groups (P < .05). The BIC values of the sandblasted and acid-etched, HYA, and HA groups were significantly higher than the sandblasted and machined groups at the 1- and 3-month examinations (P < .05). The BIC value for the HA group showed decreased value at the 3-month examination compared to the 1-month examination (P < .05).
Conclusion: The RFA, reverse torque, and histomorphometric analysis at 1- and 3-month examinations show that dental implants coated with HYA may have increased potential for osseointegration compared to dental implants with sandblasted, sandblasted and acid-etched, machined, and HA-coated surfaces.