Secondary stability achieved in dental implants with a calcium-coated sandblasted, large-grit, acid-etched (SLA) surface and a chemically modified SLA surface placed without mechanical engagement: A preclinical study.

Abstract

To assess the osseointegration of calcium-coated (CS) and chemically modified, sandblasted, large-grit, acid-etched (MS) dental implants with a lack of primary mechanical stability. Eighteen implants in CS and MS groups each were loosely placed in the mandible of six mongrel dogs and allowed to heal for 2, 4 and 8weeks. Implant stability quotient (ISQ) and implant stability test (IST) values recorded periodically and bone-to-implant contact (BIC) and the number of Haversian canals per 1mm2 measured histologically were statistically analysed (p<.05). All CS and MS implants placed survived. Compared with immediately after installation, ISQ and IST values in both groups increased significantly to over 76 at 2weeks (p<.0083) and remained stable thereafter. BIC was significantly greater at 8weeks (61.3±13.6% in CS group; 57.6±5.9% in MS group) compared to 2 and 4weeks in both groups (p<.017). There were no significant intergroup differences in ISQ, IST or BIC at different time points. Significantly more Haversian canals were observed in group CS (6.2±1.0/mm2 ) compared with group MS at 4weeks (3.7±1.8 /mm2 ; p<.05), while intergroup difference was not significant at 8weeks. Both CS and MS implants inserted without primary stability obtained osseointegration within 2weeks, and lamellar bone adjacent to the implants was first observed at 8weeks. The formation of primary osteons was more active at 4weeks in group CS than in group MS.