The association between removable partial dentures (RPD) and implants is greatly valuable, especially for class I and II Kennedy classification. Proper design, with splinting of the implants and employing attachments avoids unilateral RPD compromises.
The aim of this in-vitro study was to evaluate and compare the retention of Ball attachments and OT Equator attachments used with two splinted implants retaining unilateral mandibular (RPDs).
Materials and methods: 4 identical experimental models were fabricated and categorized into two groups according to the type of attachment used (Group I) with Ball attachments and (Group II) with OT Equator attachments. Each model received two root-form implant analogs, one at the second premolar area and one at the first molar area, Theses two implants were splinted together by a metal superstructure, with attachments used to retain the unilateral RPD. Retention of the two groups was tested and compared using a Universal testing machine.
Results: In (group I), the mean retention ± standard deviation decreased from 8.07 ± 0.86 at baseline to 5.61 ± 0.74 after 450 cycles, then decreased again to 3.13 ± 0.71 after 900 cycles. In (group II), the mean retention ± standard deviation decreased from 9.89 ± 0.93 at baseline to 6.51 ± 0.90 after 450 cycles, then decreased again to 5.62 ± 0.38 after 900 cycles.
Conclusion: OT Equator showed higher retention rates than Ball with significant differences between them after 900 cycles of insertion and removal representing 6 months usage of the implant retained unilateral RPDs.