Load bearing of different fixed prosthesis materials with various cantilever lenghts

ABSTRACT Aşkan, İ. (2023). Load Bearing of Different Fixed Dental Prosthesis Materials with Various Cantilever Lengths. Yeditepe University, Institute of Health Sciences, Department of Prosthodontic Dentistry, Phd Thesis, Istanbul. The aim of this in vitro study was to observe structural changes of CAD-CAM polyaryletherketons under load as a cantilever fixed prosthesis framework. Three different types of high performance polymers were milled from CAD-CAM blanks to test, after being cemented on an edentulous scenario [Polyetheretherketon (PEEK) (PE), Polyetherketonketon (PEKK) (PK), Bio High Performance Polymer (Bio-HPP) (BH), Lazer sintered Cr-Co alloy frameworks serve as the control group (CC). Samples have been prepared to create two subgroups by two different cantilevers [14 mm cantilevered samples (PE14, PK14, BH14, CC14) (n=10); 21 mm cantilevered samples (PE21, PK21, BH21, CC21) (n=10)]. Each specimen underwent thermocycle and cemented on the main model with resin reinforced glass ionomer cement. Specimens reciprocated vertical load 2 mm away from the most lateral point of cantilever beam, on Instron Universal Testing Machine 3228, carrying out a load to failure test. Decementation and deformation values have been recorded. The conformity of the parameters to the normal distribution was evaluated by Kolmogorov-Smirnov and Shapiro-Wilks tests. The data was analyzed with two way ANOVA. There was no statistically significant difference between the material groups in terms of decementation and deformation values [(p:0.122 ; p>0.05 and (p:0.337 ; p>0.05)]. There was a statistically significant difference between the cantilever lenghts in terms of decementation and deformation values [(p:0.005 ; p<0.05) and (p:0.001 ; p<0.05)]. Within the limitations of this study, load to failure results can be showm respectively as; BH14, PK14, PE14, PK21, BH21, PE21 (¯x deformation values; ▁(+)288 N, ▁(+)255 N, ▁(+)249,5 N, ▁(+)150,5 N, ▁(+)148 N, ▁(+)131 N). Keywords: Fixed Prosthesis, PEEK, PEKK, Bio-HPP, Cr-Co, Cantilever, CAD/CAM