The Effect of Two Body Wear on CAD/CAM PEEK against Monolithic Zirconia, Lithium Disilicate, and Tooth Enamel; “An in vitro study”

Abstract

Statement of the Problem:The fracture of the veneering material of any bi-layered fixed restoration is a decisive factor. Recently developed PEEK has gained an attention in being used in the oral cavity as a fixed partial denture framework. However, deciding whether PEEK restoration will withstand function and retain its form is still under investigation.Introduction; PEEk which is basically a result when manufacturer included ceramic filler particles in its matrix BioHPP, making it a suitable polymer to be used as a temporary and permanent restorations. To test whether this new BioHPP will withstand the function in the oral cavity, in terms of wear and volumetric loss, and determine its efficacy as permanent or final restoration.Materials and Methods; 30 BioHPP discs, apposing human enamel and lithium disilicate and zirconia six millimeter hemispheres, were tested in a dual axis chewing simulator. The number of cycles was 120,000 corresponding to six months intra-orally. Then the specimens were scanned pre and post testing, and volume was evaluated using Geomagic qualify software.Results; There was a statistically significant difference between volume loss in the three groups (P-value = 0.003, Effect size = 0.361). Pair-wise comparisons between the groups revealed that enamel showed the statistically significantly highest mean volume loss whereas L. Zirconia showed lower mean value and Lithium Disilicate showed the lowest mean weight loss. Conclusion;BioHPP is a convenient material to use intra orally in a monolithic form, its also expected to cause less wear than most used ceramics.

Color Stability of Three Different Types of Monolithic CAD/CAM Esthetic Restorations After Exposure to Artificial Accelerated Aging (An In-vitro study)

“…This leads to hydrolysis of the silane, reducing the retention of the filler particles and therefore color change "discoloration" of the material. 31,34,41 IPS e.max CAD showed the least color change among the three investigated materials, and this agreed with previous studies. 8,39,42 Color change of IPS e.max may be attributed to the metal oxides which added to ceramic to obtain the color shades and under the UV light these metal oxides can very easily break down and peroxides compound may develop and result in color change.…”

“…To convert CAD/CAM blocks to cylinders, a cylindrical shape with 10mm diameter and 14mm long was designed using Z brush software. 34 The designed cylinder was exported as standard tessellation language (STL) file and then imported into CORiTEC SmartControl TM software. 34 The design was nested into CAD/CAM blocks and milled using CORiTEC 250i CAD/CAM milling machine.…”

“…34 The designed cylinder was exported as standard tessellation language (STL) file and then imported into CORiTEC SmartControl TM software. 34 The design was nested into CAD/CAM blocks and milled using CORiTEC 250i CAD/CAM milling machine. 34 After that, the cylinders were cut into discs with uniform thickness of…”

“…34 The design was nested into CAD/CAM blocks and milled using CORiTEC 250i CAD/CAM milling machine. 34 After that, the cylinders were cut into discs with uniform thickness of…”

“…Additionally, most polymers have functional groups in their molecular chains that absorb UV light. 31,34,41 AAA leads to the degradation of the matrix/silane/filler, as the composite absorbs the water that penetrates the filler/resin interface. This leads to hydrolysis of the silane, reducing the retention of the filler particles and therefore color change "discoloration" of the material.…”