The Influences of Implant Angulations in One and Two Directions on the Retentive Properties of Overdenture Attachments: An In Vitro Study

Abstract

Implant alignment is an important factor in overdentures retained by solitary abutments. In this study, the effect of implant angulations in two directions, on the amount of retention of attachments was evaluated. Ninety models were divided into nine groups of two blocks each; one for two implants and one for two attachments. The implants were placed either parallel to, at 5°, or at 10° relative to the reference plane. The attachments were related to the implants with a 0, 5, or 10° angulations. The direction of the implant was either labial or distolabial. The initial and the subsequent retention values of each sample were measured after each 500 cycles of insertion and removal. The measurements were repeated for five consecutive 3,000 cycles, and the results were analyzed by means of one-way ANOVA and Tukey HSD tests. Group 9 with a 10° distolabial tilt of the implants and of their attachments showed the highest initial retention, whereas group 1 with a 0° angulations and parallel attachments showed the lowest (6.9 ± 0.28 and 3.88 ± 0.19 N, respectively). The initial retention and the final loss of retention was significantly higher in those groups with the distolabial tilt of the implants (p < 0.05). Within the limitations of this study, it was demonstrated that the more divergent the implants and their retentive components, the higher their initial retention and the lower their final retention may be.

Using an Attachment System with PEEK Matrices for Single-Implant Overdentures: In Vitro Retention Force

“…From the linear regression analysis, it was deduced that the highest retentive forces amongst all attachment groups were at a platform inclination of 0°, and the largest loss in retention across all groups was present at an incline of 10° followed by 0° and 20°. The present results indicate that the wear and tear of retentive components may not be affected by the parallelism of multiple implants or a perfectly linear path of insertion of a denture on an implant/fixture as previously believed [ 27 , 28 , 29 , 30 ]. However, 20° may be the limit for angulation.…”

In vitro retention force measurement for three different attachment systems for implant-retained overdenture

“…The analog holes were prepared 22 mm apart from each other by the aid of an acrylic stent to ensure parallelism and avoid discrepancies arise from misalignment of attachment components which accelerates wear mechanisms. [ 3 10 11 ] It was made of clear heat cure acrylic resin (Acrostone Manufacturing and Import Co., Cairo, Egypt) with the same length (4 cm), width (2 cm), but of a lower thickness (1 cm) with two vertical metal sleeves installed parallel to each other by aid of the surveyor (Ney Surveyor, Dentsply, NY, USA), 22 mm apart from each other. Holes were made so that the top of the two implant analogs (Ankylos, Dentsply Friadent, Mannheim, Germany) 4 mm in diameter, 12 mm in length was 1 mm below the top surface of the base block.…”