EVALUATION OF STRESS DISTRIBUTION AROUND IMPLANTS RETAINING MANDIBULAR OVER-DENTURES WITH TWO DIFFERENT ATTACHMENT SYSTEMS:AN IN- VITRO COMPARATIVE STUDY

The clinical success of dental implant depends on the biomechanics and proper distribution of the occlusal load, the use of thermoplastic materials as (peek & nylon) in implant supported overdentures is an excellent choice to overcome occlusal overload. Aim: The aim of this in-vitro study is to evaluate stress distribution around implant retaining mandibular over-dentures with two different attachment systems (Novaloc & Equator). Materials and Methods: A mandibular 3D-printed cast model from the epoxy resin was used for this study after selection of the implant sites, surrounded by four channels of estimated depth, to allow a 2mm thickness of epoxy resin between the strain gauge rosettes and the implant. Two implants were inserted parallel to their sites in the 3D-printed model, attachments were screwed to implants. Sixteen attachments were divided into two groups (eight Novaloc attachment and eight Equator attachment). Strain gauges were cemented around the implants to measure the micro strain. Vertical and oblique (unilateral & bilateral) load was applied using a universal testing machine, and stress analysis was made. Results were collected and analyzed using statistical software. Result: There was a significant different between Novaloc and Equator on Stress Distribution around Implants in Implant-Supported Prostheses. Conclusion: Both Novaloc and Equator attachments are less traumatic to underlying bone in implant supported overdenture, with Novaloc attachment being less traumatic under oblique loading than Equator attachment.