Early Evaluation of a New Cervical Implant Design to Improve the Perimplant Tissues Healing: A Preclinical Experimental Study

Objectives: The aim of the present preclinical study, using rabbits as an experimental model, investigated the effects of a new implant design that incorporates specific changes in the cervical portion, using a conventional implant design as a control group. Materials and Methods: Ten rabbits and 40 dental implants with two different macrogeometries were used. Two groups were formed (n = 20 per group): Collo group, where implants with a new cervical design were used, which present a concavity (reduction in diameter) in the first 3.5 mm and with this portion of the implant without surface treatment; Control group, where conical implants with conventional design were used, which feature surface treatment throughout the body. All implants present dimensions of 4 mm in diameter and 10 mm in length. The initial implant stability quotient (ISQ) was measured immediately after the implant insertion (T1) and immediately after removing the pieces with the implants. The animals (n=5 animals/time) were euthanized at 3 weeks (T1) and 4 weeks (T2). Histological sections were prepared and, the percentage of bone-implant contact (BIC%) and the tissue area fraction occupancy (TAFO%) were analyzed in the pre-determined cervical area of the first 4 mm from the implant platform. Results: The ISQ values showed no statistical differences in T1 and T2 (p = 0.9458 and p = 0.1103, respectively). However, in T3 superior values were found for the Collo group (p = 0.0475). Higher BIC% values were presented in samples from the Collo group compared to the Control group, with statistical differences (3-weeks p = 0.0009 and 4-weeks p = 0.0007). TAFO% (new bone, medullary spaces, and collagen matrix) had statistical differences between the groups at each evaluation time. Conclusion: Within the limitations of the present pre-clinical study, the results of this study suggest that the new implant design with changes in the cervical portion (Collo group) presents significant advantages concerning the conventional implant (Control group), regarding stability in the initial times and osseointegration.