Evaluation of Strains Around Distally Inclined Implants Retaining Mandibular Overdenture with Ti Si Snap Attachment

Document Type : Original Article


The Departments of BDS, Faculty of Dentistry, Al-Azhar University*, Removable Prosthodntics** and Dental Biomaterials***, Faculty of Dentistry, Alexandria University


Abstract Background: Implant-assisted removable overdentures had fewer difficulties than traditional full dentures in the rehabilitation of a totally edentulous arch. A two-implant overdenture should be the minimal standard of care for an edentulous mandible, according to the McGill consensus statement. Aim of Study: To compare strain around two implants retained mandibular overdenture with different degrees of distal inclination 0°, 17.5, 35°  and different types of retention sil, for the Titanium Silicon snap attachments. Material and Methods: The sample size was calculated using the following assumptions: Alpha error=5% and study power=80%. The sample size for each group was projected to be four, however this will be raised to five to account for laboratory processing inefficiencies. The total sample size required to detect the effect of distal inclination of implants at different angles using Ti-si snap attachment=numbers of groups x numbers per group=6 X 5=30, A total of 3 ready made completely edentulous epoxy models were used. To imitate robust edentulous ridge mucosa, an approximately 1.5-mm thick layer of auto polymerized resilient silicone soft lining material was employed for each model. Results: Shapiro-Wilk tests were employed to determine whether data were normally distributed. Parametric and regularly distributed data were found in the analysis. Descrip-tive data for peri-implant strain values comprised the mean, the standard deviation of the range, the lowest, and the highest value. Different groups (0º,17.5º, and 35º implant inclinations) and measurement locations (RD, RM, LM, and LD) were studied using a general linear model (two-Way ANOVA), with post hoc tests and least significant differences (LSD) for multiple comparisons. Conclusion: As the angle of distal implant inclination rises, the peri-implant strain surrounding two implants put in the canine region to hold mandibular overdentures with TiSi attachments increases. This means that the implants should be placed perpendicular to the top of the ridge, so that tension is transferred as little as possible into the peri-implant area. The effect of different retention sil used, strain increased when retention sil with higher shore hardness values was used in all inclinations.