Effects Of Span And Detachment On Snap-On Abutment Retention

This study aimed to evaluate the effect of prosthetic span and repeated detachment on the retention of a newly developed snap-on abutment system. Implant fixtures (4.5mm×10mm) were placed in resin block using a parallelometer. Four groups were designed to represent different prosthetic spans: P1 (first premolar), P1P2 (first and second premolars), P1M1 (first premolar and first molar), and P1M2 (first premolar and second molar), with five specimens per group (n=5). Crowns were designed using CAD software and fabricated through 3D printing using PMMA resin. Abutments (4.8mm×2mm) were connected to the implant fixtures, and detachable cylinders (4.8 mm×6mm) were connected to the abutments via a snap-on mechanism. Retention was measured using a universal testing machine and recorded at initial detachment and after 5, 10, 15, and 20 repeated cycles. Data were analyzed using one-way and repeated measures ANOVA (p<0.05). At the initial detachment, P1 and P1P2 showed statistically significant differences from each other and from P1M1 and P1M2 (p < 0.05). From the 5th to the 20th cycles, only P1 remained significantly different. Retention significantly decreased up to the 10th cycle in P1 and the 5th cycle in P1P2, while no significant change was observed in P1M1 and P1M2. Multi-unit bridges maintained stable retention, whereas single crowns exhibited significant retention loss. Although initial retention was influenced by span, repeated detachment led to stabilization of retention.