STRAIN ASSESSMENT OF COBALT CHROMIUM VERSUS POLY-ETHER-ETHER-KETONE FOR REINFORCING MANDIBULAR OVERDENTURE ASSISTED BY TWO IMPLANTS (A COMPARATIVE IN-VITRO STUDY)

INTRODUCTION: Patients with a traditional denture may have difficulty chewing because of the absence of retention. Recently, using two un-splinted implants assisted overdenture to overcome the retention problem. But still Acrylic material has problems; such as lowers impact, fatigue strengths, and fracture. Reinforcement of acrylic denture base to avoid fracture by a variety of materials such as; Metal reinforcement, fillers like carbon fiber, and Poly-Ether-Ether-Ketone (PEEK) is frequently utilized in dentistry and is seen as a viable alternative to traditional materials. AIM OF THE STUDY : Compare between Two different denture base reinforcement materials (CoCr) and (PEEK) in comparison to acrylic denture base on strain around two implant-assisted mandibular overdenture and on ridge area. MATERIALS AND METHODS: 3 epoxy models were used with two implants placed at the canine region. 8 mandibular overdenture were constructed for each group; (group A) Acrylic overdenture without reinforcement, for (group B) and (group c) acrylic overdenture were reinforcement by (CoCr, PEEK) respectively. Six linear strain gauges were used at the mesial and distal of each implant, and under the lower second molars bilaterally. Strain measurements were taken under central and unilateral loading around the two implants and on the ridge regions. RESULTS: No significant difference between all groups upon application of central load 100N on ridges. However, group C showed lower strain values upon application of central and unilateral loading 100N. CONCLUSION: PEEK reinforcement material showed less strain values with favorable stress distribution when compared to Acrylic and cobalt chromium reinforcement material for implant-assisted mandibular overdenture.