Influence Of Implant Design In Osseointegration And Streptococcus Mutans Adherence

Objective: The purpose of the present study was to analyze and compare, in an animal model, the bone apposition at the interface of screw implants with rough surface (commercially available implants) to cylindrical implants with porous surface after various healing periods. In addition, the study aimed at elucidating the influence of the surface configuration of the implants on Streptococcus mutans adherence.

Method: Using powder metallurgy technique, a new method was developed to produce titanium implants presenting a dense core integrated to porous surface to increase bone-implant contact (BIC). Sixty implants were placed in 15 rabbits. In each rabbit, two experimental and two control implants were placed in the right or left tibia. The experimental implants were inserted under pressure into the surgical cavity, while the control implants were self-threaded. The rabbits were euthanazied after 4, 8 and 12 weeks post-insertion for histologic nondecalcified processing and morphometric evaluation of BIC.  Sixteen implants, eight experimental and eight control, were incubated with S. mutans to evaluate adherence in each type implant. Analysis of variance with repeated measures and a t Student test were applied, respectively.

Result: Histology showed intimate bone-implant interfaces without soft tissue intervention, in both groups. Porous surface cylindrical implants showed a higher BIC (78.90% ± 9.47) than the rough surface screw implants (61.22% ± 14.12) (p=0.001), but there was no significant difference in the S. mutans adherence (p=0.351). The percentage of BIC was similar between the healing periods (p=0.07), but it gradually increased over time.

Conclusion: Within the limitations of this study, the new implant with dense core integrated to porous surface increased BIC, but without provoking enlarged S. mutans adherence when compared to the screw implant commercially available. Thus, this new implant can emerge as an innovative procedure, particularly for areas presenting poor bone quantity and quality.