Mahmoud Ahmed Kamel, Manal Rafei Hassan And Raiessa Mohammed Hashem,

ABSTRACT

Objectives: The Purpose Of This Study Is To Investigate The Wear Of Recently Used CAD/CAM Ceramics Against Natural Tooth Structure In A Chewing Apparatus.

Materials and Methods: Thirty Rectangular Ceramic Samples (12x14x2) Were Divided Into Three Groups (n=10): Translucent Zirconia (Zr), Lithium Disilicate (e-max) And Hybrid Ceramic (vita Enamic). Natural Human Premolar Cusps Were Used As Antagonists. Ceramic Samples And Premolar Antagonists Were Dynamically Three-body Loaded In A Dual Axis Chewing Simulator With 49 N For 150,000 Loading Cycles. Wear Measurement For Ceramic Samples And Premolar Antagonists Were Calculated Using Weight Loss (gm.), And Surface Roughness Measurements (?m). Data Were Statistically Analyzed With One-way ANOVA Test, Followed By Post-hoc Test Between Groups.

Results: A Significant Difference Was Detected Between The Mean Values Of Weight Loss (gm.) Of The Three Tested Ceramic Materials And Their Premolar Antagonists With The Greatest Weight Loss Detected In Polymer-infiltrated Ceramics (Mean ? SD: 0.0094?0.0028) Followed By Lithium-disilicate ( 0.0032?0.0009) And The Lowest Loss In Zirconia (0.0009?0.0002) And P Value Of (<0.001). For The Premolar Antagonists; The Greatest Loss In The Mean Weight Of Premolar Cusps Was Detected In Cusps Opposing Zirconia (0.0113?0.0018), Followed By Lithium-disilicate (0.0038?0.0009) And The Least Loss Detected In Cusps Opposing Polymer-infiltrated Ceramics (0.0003? 9) And P Value Of (<0.001). A Significant Difference In Surface Roughness (?m) In The Tested Ceramic Samples And In The Antagonistic Premolar Cusps. Surface Roughness Increased After Wear Testing But The Greatest Increase Was Found In Polymer-infiltrated Ceramic Samples (0.0056?0.0008) Followed By Lithium Disilicate (0.0033?0.0009) And The Least Change Was In Zirconia Samples (0.001?0.0003 And P Value Of (<0.001). Surface Roughness Of Zirconia Antagonistic Premolar Cusps Showed The Greatest Increase (0.0042?0.0007) Followed By Lithium-disilicate (0.0024?0.0009), While The Least Increase In Roughness Was In Cusps Opposing Polymer-infiltrated Ceramic Samples (0.0004?0.0001) And P Value Of (<0.001). Conclusion: Zirconia Showed The Best Wear Behavior Followed By Lithium-disilicate And Polymer-infiltrated Ceramics. Polymer-infiltrated Ceramic Is The Most Antagonist-friendly Among Tested Materials.