Stress analysis of two different attachments for a single implant retained mandibular overdentures in the midline (In vitro study)

Abstract

Objective: aiming to record the induced micro-strain around one installed implant in the midline of a completely edentulous mandible using strain gauges utilizing an implant retained overdenture with two different types of attachments Ball and CMLOC attachment. Materials and methods: An acrylic resin test resin test model representing a completely edentulous lower arch was used.The distal part of the residual ridge was covered with silicon based soft liner to stimulate the mucopcriostcum. Steps of complete denture fabrication was followed in conventional manner .Duplication of the finished denture was carried out to be used as a surgical stent .A single implant installed in the midline. After the implant was installed in the acrylic resin cast, the ball attachment was screwed to the implant. The denture was prepared for the direct pick up procedure, the same procedure repeated for CM IOC attachment. Four strain gauges around were installed on all surfaces of implant (Buccal. Lingual. Mesial .Distal) to monitor the effect of the applied loads vertical on the two types of attachments. A vertically load applied of 100 N static load was applied by using universal testing machine at two different sites (unilateral left first molar and bilaterally). Results : When the load applied unilaterally on the left side ,it was shown that the single implant retained overdenture with the Ball attachment has shown higher microstrain than the CMLOC ,average microstrain for Ball (391.26) N , and for CMLOC (223.22) N. When the load applied bilaterally, the single implant retained overdenture with the CMLOC (269.05)N attachment has shown higher microstrain than the Ball (106.79) N. Conclosion: It can be concluded from this invitro study that the newly introduced attachment the CMLOC lends to show a better performance with regards to the micro-strains induced around the implants. On the other hand the Ball attachments tends to show more micro-strain around the implants.