Abstract:

  Background and Aim: Angulation of implant and attachment in regard to path of insertion of prosthesis would affect the retention and longevity of the overdenture. The purpose of this study was to evaluate the effect of 5 and 10 degree distolabial of implants and attachments on the retention and longevity of the overdenture.

  Materials and Methods: This in vitro experimental study was conducted on 25 samples, divided into 5 groups. Each group included twin implants and attachments which were placed into acrylic blocks. Parallel implants and attachments comprised the control group (Group 1). The study groups (Group 2-5) consisted of implants and attachments with 5 and 10 degrees of distolabial inclination. All samples were kept wet using artificial saliva. The level of retention was then measured from cycle one to cycle 3000 (equivalent to 750 days of longevity) using the Santam retention test device. Data was analyzed by ANOVA and Paired T-test.

  Results: The initial retention measured in groups 1-5 was: (3.8± 0.34),(5.6±0.66),(6±0.66),(6.8±0.3) and (6.9±0.28) respectively. The reduction in retention after 3000 cycles in group 1-5 was measured to be: (11%), (32%),(31%), (38%) and 36% respectively. Statistical analysis revealed no significant difference between the initial and final retention levels among the case groups (p<0.2). However, there was significant difference between the control and the case groups in terms of retention (p<0.05).

  Conclusion: Distolabial inclination of the implant results in an initial increase of retention level followed by a reduction of retention level over time. This degree of inclination has no major influence on the longevity of the implant.

  Key words: Overdenture, Angled implant, Angled attachment, Retention