Amany Mohamed Bayoumi, Mai Mahmoud Yousry And Rasha Rafaat Hassan,

ABSTRACT
Objective: This Study Was Conducted To Evaluate The Surface Roughness Of Machinable Ceramic, Composite, And Hybrid Blocks Before And After Erosion And/or Abrasion Challenge.

Materials and Methods: A Total Of 90 Specimens Of Ceramic, Hybrid And Composite CAD/CAM Blocks Were Tested In The Study. They Were Divided Into 3 Main Groups Of 30 Specimens Each, Then Subdivided Into 3 Subgroups Of 10 Specimens Each According To Challenge. First, Erosion Challenge; Where Specimens Were Exposed To Pepsi-Cola ,Second, Abrasion Challenge; Where Half Of The Specimen Of This Subgroup Were Subjected To The Abrasion Using Powered Toothbrush With A Dentifrice, While The Other Half Was Subjected To Toothbrush Abrasion Without Toothpaste. And Third, Erosion/Abrasion Challenge Where The Specimens Were Subjected To An Erosive Followed By An Abrasive Challenge Either With Or Without An Abrasive Toothpaste. For Each Specimen, An Optical Profilometer Was Used To Record The Surface Roughness Before (baseline) And After The Erosive And/or Abrasive Challenge. Surface Roughness (Ra) Was Then Calculated And Statistically Analyzed Using Three-way ANOVA And Bonferroni?s Post-hoc Test.

Results: Regarding The Surface Roughness Results, With Different Challenges Either Before Or After Brushing, Without Or With Toothpaste; There Was No Statistically Significant Difference Between Mean (Ra) Of The Three Materials. Conclusion: The Surface Roughness Of CAM/CAM Blocks Was Not Influenced By Any Of The Tested Erosion And/or Abrasion Challenges.