DETERMINATION OF THE RETENTION STRENGTH OF A REMOVABLE DENTAL PROSTHESIS SUPPORTED BY A VARIOUS NUMBER OF MINI-IMPLANTS

Abstract

Introduction. Retention is one of the most important factors in the successful use of removable dentures supported on dental implants, as well as conditionally removable dentures. In the context of using mini-implants as supporting elements, the number of implants has been proposed as the primary variable affecting denture retention, mechanical stability, durability of use, and patient satisfaction. Methodology and methods of the study. The study aimed to investigate the retention force of retainers for complete removable dentures with fixation on dental mini-implants in different design variants in laboratory conditions. Jaw models with four parallel installed miniimplants were used. O-ring matrix sleeves were fixed to the acrylic plate of the prosthesis. The retention force was determined using a strain gauge, with the maximum load upon detachment recorded in Newtons. For each configuration (1, 2 side by side, 2 opposite, 3 and 4 supports) 10 measurements were performed. Summary of the primary study material. A gradual increase in retention force with increasing number of mini-implants was established: 5.31±1.15 N (1 support), 9.72±1.81 N (2 side by side), 11.90±3.17 N (2 opposite), 18.45±3.31 N (3 supports) and 21.73±2.95 N (4 supports). The ANOVA test revealed statistically significant differences between groups (p<0.001). Paired comparisons showed significant differences between all groups, except for two configurations with 2 implants (p=0.14). The effect size was large (η² = 0.846), indicating a strong association between the number of implants and retention. The obtained data confirm a linear relationship between the number of supports and the prosthesis's fixation force and are consistent with the current literature. An increase in the number of mini-implants significantly increases retention, although the increase between three and four supports is less pronounced. The limitations of the study include the model's laboratory nature and the absence of clinical factors, so the results require further clinical verification. Conclusions. The use of two, three, and four supports progressively increases the retention force of a removable denture supported by dental implants. The location of implants in non-adjacent segments of the dentition in a two-support design also increases retention force compared to when the supports are adjacent.