Supervisors info:
Πολυχρονάκης Νικόλαος, Αναπληρωτής Καθηγητής, Τμήμα Οδοντιατρικής, Σχολή Επιστημών Υγείας, ΕΚΠΑ
Σαραφιανού Ασπασία, Επίκουρη Καθηγήτρια, Τμήμα Οδοντιατρικής, Σχολή Επιστημών Υγείας, ΕΚΠΑ
Ιόλη Αρτοπούλου, Επίκουρη Καθηγήτρια, Τμήμα Οδοντιατρικής, Σχολή Επιστημών Υγείας, ΕΚΠΑ
Summary:
Purpose: The aim of this study was to evaluate the influence of accelerated aging on the color and translucency parameter (TP) of acrylic denture teeth.
Materials and Methods: Twenty acrylic teeth of each of four different brands (Cosmo HXL-Degudent, Creopal-KLEMA Zahnproduktion, Executive-Degudent and Ivostar-Ivoclar Vivadent, n=80) were divided in two groups, from which the first group was submitted to AAA procedure (n=10) and the second served as control (n=10). The teeth of AAA groups (n=40) were aged in an accelerated aging chamber for 144 hours at 765W/m2, corresponding to 432 cycles of 20 min. Color and translucency changes (ΔΕ* and ΔTP*) of all teeth were measured using a tristimulus colorimeter, based on the CIE L*a*b* system and CIEDE2000 formula, at baseline and 24h, 72h and 144h time intervals. The data were analyzed using three-way repeated measurements ANOVA at a statistical level of significance a=0,05.
Results: Statistical analysis on baseline values (pair-wise cell comparisons on rm ANOVAs) indicated significant differences among brand groups for all parameters . ΔE*ab values, 144h after AAA ranged from 1,68 to 2,63 units. Repeated measures ANOVAs for ΔΕ*ab data, indicated significant differences between AAA treatments and brands. Due to time x AAA, time x brand and AAA x brand interactions, post-hoc pairwise comparisons indicated differences. ΔΕ00 values, 144h after AAA ranged from 1,20 to 2,07 units. Repeated measurements ANOVAs showed significant differences among time periods, brands and AAA treatments, which located by pairwise multiple comparisons due to two-factor interactions. F-distribution values, estimated by rm ANOVAs, indicated that the greatest effect on variances in L*, a* and b* parameters was related primarily to brand type and AAA treatments. In ΔE*ab and ΔE00 the greatest effect on their variances was related to AAA treatments. TP00 values ranged at 144h from 0,65 to 1,72 units and found to have not significant differences among brands. The change from baseline (ΔTP) was also not significant across time or AAA treatments. Correlation analysis showed insignificant or very small association between TP and L* (r=-0.048), a* (r=-0.278), or b* (r=-0.198) coordinates.
Conclusions: Αging-dependent color changes in ΔΕ*ab and ΔΕ00 units were noticed for all brands. However, they were below the clinical acceptability threshold. Cosmo HXL teeth showed the best color stability among all brands. ΔTP values were below the determined perceptibility threshold for all brands, with Ivostar teeth showing the lowest TP changes.
Clinical Significance: The color stability of acrylic denture teeth should be routinely reexamined since aging may cause significant color changes. The selection of the type of acrylic teeth is a decisive factor for the optimal esthetic performance of complete dentures during the clinical use.
Keywords:
Acrylic teeth, Color, Translucency, Accelerated aging
