Microstrain analysis of implants retained complete mandibular overdenture by using two different attachments (an in vitro study)

Purpose The aim of this work is to evaluate strain analysis of two piece implants retained complete edentulous mandibular overdenture with two different attachment systems bar and clip attachment and extracoronal resilient attachment (ERA + bar) by using strain gauge analysis. Materials and Methods This in vitro strain analysis of implants retained complete mandibular overdenture with two attachments carried out on two completely edentulous mandibular models covered by 2 mm thickness mucosa. Two finished dentures were constructed one denture for each group. Group 1: two implants at canine region with bar attachment. Group 2: two implants at canine region with bar and ERA attachments. Four strain gauges were cemented around each implant, buccal, lingual, mesial, and distal. A 50 N static load was applied on the experimental model in vertical and oblique directions. Strain data of each group was collected tabulated and statically analyzed. Results The result of this study revealed that the difference of microstrain between the two groups was significant as the maximum microstrain recorded was found in group 1 followed by group 2. The oblique forces increase the resulting strain than vertical forces. Conclusion There are different patterns of strain analysis at bone–implant interface between the studied attachment designs, the ERA-bar combination exhibited better strain analysis than bar-clip system