Comparative Stress Analysis Study Of CAD/CAM Milled PEEK And Zirconia Primary Copings In Double Crown PEEK Framework Mandibular Partial Denture After 1 Year Simulated Function

Abstract

Aim of the study: The objective was to assess and compares the effect of PEEK and Zirconia primary copings in milled double crown PEEK framework. Materials and methods: One cast was fabricated simulating Kennedy Class I with the premolars as the last standing abutment. The primary copings were classified into two groups, milled PEEK group I and milled Zirconia group II. Two milled PEEK frameworks were used. Four strain gauges were installed bilaterally in the model. A load of 100 N was applied to the area of the first molar bilaterally. The same procedure was repeated 10 times. Cyclic loading was applied simulating 1 year of function. Strains induced on the abutments during bilateral loading were evaluated before and after chewing simulation. Results: The highest compressive micro-strain was recorded at channel (4) after cyclic loading for PEEK group 359.00±5.055 µm/m followed by channel (2) 356±13.293 µm/m. While the least compressive micro-strain was recorded at channel (1) before cyclic loading for the Zirconia was 150±7.817 µm/m. There was significant difference in channels ( 2) and (4) regarding PEEK group before and after cyclic loading. While for Zirconia group there was significance difference in channels ( 1) and (3) before and after cyclic loading where P value was<0.05. There was significant difference in all the channels before and after cyclic loading. Conclusion: PEEK and Zirconia primary copings showed different distribution of stress, as PEEK primary coping transmitted more stress to the supporting structures.

<i>In-vitro</i> evaluation of wear characteristics, microhardness and color stability of dental restorative CAD/CAM materials

“…Loading force was considered as a significant parameter, effecting the loaded object for fatigue 13) . The number of cycles range from 10,000 to 3.6 million cycles (0.04-14.4 clinical years), and 240,000 stress cycles were determined to simulate one year period, clinically 14) . In this study, the specimens were aged with 240,000 chewing cycles to mimic one-year of clinical aging.…”