Evaluating Surface Roughness and Gloss of Manufactured Pedodontic Anterior Zirconia Crowns

Objectives: Determine gloss and surface roughness of pedodontic anterior zirconia crowns.
Evaluate the relationship between gloss and surface roughness.
Methods: The gloss of pedodontic anterior zirconia crowns from 3 manufacturers (NuSmile, EZ-Pedo and Kinder Krowns) was measured using a glossmeter (Novo-Curve, Rhopoint Instruments) and surface roughness was measured using a contact surface profilometer (Talysurf Plus, Taylor Hobson). The crowns were placed on the aperture of the glossmeter with facial and lingual surfaces exposed to a light beam and covered to prevent outside light from entering the field. Three values for each surface were taken for the samples, and averaged. Data were analyzed using one-way ANOVA and Tukey post hoc test at the 0.05 level of significance. The crowns were mounted horizontally and vertically with same surfaces exposed. The surface roughness (Ra, um) of the unprepared surface was measured using a tracing length of 1 mm and a cutoff value of 0.25 mm to maximize filtration of surface waviness. Three tracings in horizontal and vertical manner were performed on each surface. Mean values and standard deviations of Ra were determined. Data were analyzed by analysis of variance and Tukey at a 0.05 level of significance.
Results: Main effects were significant for crown type (p<0.01) and crown surface (p<0.01). A significant interaction between crown surface and type was also shown (p<0.001). There were significant differences in mean gloss among the three crown types (p=0.01) with NuSmile showing the highest gloss followed by EZ-Pedo and Kinder Krowns. Mean gloss was highest on the lingual surfaces (p<0.01). NuSmile displayed the overall lowest mean Ra (p<0.001) followed by EZ-Pedo and Kinder Krowns (p<0.003). When comparing Ra for lingual and buccal surfaces, there were significant interactions between crowns and surfaces (p<0.001). NuSmile showed the lowest lingual Ra (1.9) followed by Kinder Krowns (3.2) and EZ-Pedo (3.7). The lowest Ra values for the buccal surfaces were measured on EZ-Pedo (2.5), followed by NuSmile (2.8) and Kinder Krowns (4.3).
Conclusions: NuSmile displayed the highest gloss and lowest surface roughness compared to Kinder Krowns and EZ-Pedo zirconia crowns. Kinder Krowns performed lowest in gloss and surface roughness.