Nano-Hybrid Versus Micro-Hybrid Composite as Reinforced Resin for Ribbon Bar Attachment

Abstract

Purpose: The goal of this study was to compare and evaluate stress transmitted to an overdenture abutment tooth supported by polyethylene ribbon bar reinforced composite resin of hybrid type, the hybrid type includes Nano-hybrid composite and Micro-hybrid composite. Methods: Edentulous educational acrylic model modified to receive two canine teeth and duplicated to ten models. Polyvinyl silicon impression material was packed to simulate mucosa covering the ridge. The canines prepared to receive a metal jacket and then infibra ribbon bar constructed on the abutments, mandibular overdenture constructed to each model over the bar, the ten models divided equally into two groups, Group I: Five models received mandibular overdenture supported by two canines splinted with ribbon fiber bar reinforced with Nano-hybrid composite. Group II: Five models received mandibular overdenture supported by two canines, splinted with ribbon fiber bar reinforced with Micro-hybrid composite. Installation of strain gauges around each surface of the abutment, Universal testing machine used to apply load to each model Unilateral (50 N) and bilateral (100 N) vertical static load applied at 1st molar area to measure µ-strains at buccal, lingual, mesial and distal surfaces of the abutment. the outcomes collected and statistically analyzed to compare between the two groups. Result: -Infibra ribbon bar reinforced by Nano-hybrid composite and infibra ribbon bar reinforced by micro-hybrid composite exhibits No significant difference of microstrain transmitted to overdenture abutment except the labial surface. - Under bilateral loading, Infibra ribbon bar reinforced with a Nano-hybrid composite bar transmit higher microstrain to all labial, lingual, and mesial surfaces of overdenture abutment than infibra ribbon bar reinforced with Micro-hybrid composite except the distal surface. Conclusion: -Infibra ribbon bar reinforced with hybrid type composite decrease stresses transmitted to mandibular overdenture abutment -Regarding stress distribution, Micro-hybrid composite is the material of choice to construct infibra ribbon bar over Nano-hybrid composite.