Evaluation of polished and unpolished acetal resin clasp color with different beverages (in vitro study)

Background: Clasp materials play a critical role in overall aesthetic outcomes of removable partial dentures. The long-term maintenance of these outcomes depends on color stability of these materials. Staining of prosthodontics materials may result in patient dissatisfaction and additional expense for replacement.
Purpose: The purpose of this in vitro study was to evaluate the effect of various commonly consumed beverages on the color stability of Acetal resin clasps when being polished or left non-polished.
Materials and methods: A normative class IV Kennedy partially edentulous maxillary heat cure acrylic resin model was chosen, duplicated to obtain the stone master casts .10 Acetal resin RPDs were constructed and finished. A mechanical polishing was performed for the ten left clasps of Acetal resin RPDs while leaving the right ones to be non-polished. Before immersion, Acetal resin RPDs we reanalyzed for color characteristics against a gray background with A3 using a spectrophotometer. They were immersed infour beverages media (tea, coffee, cola, and orange juice).The Specimens were removed at 1, 7, and 28 days respectively, desiccated, and analyzed by the spectrophotometer.
Results: The results reported statistically significant differences between polished and non-polished clasps for both tea and orange juice solutions (0.03* and 0.006* respectively).
With respect to (L) parameter (lightness), higher mean values were revealed for non-polished Acetal resin clasps when being immersed in tea and orange juice solutions (71.1±2 2.7 and 72.5 ±1.28 respectively).Whilst this significant difference is also for coffee solutions only (P=0.004*) concerning (A) parameter (red/ green value).No significant difference was revealed for (B) parameter (yellow/ blue value) and (W) (whiteness) when immersing Acetal clasps (polished and non -polished) in all solutions under investigation.
Conclusion: Color changes were exhibited by non-polished clasps specimens immersed intea, coffeeand orange juice solutions. Polishing procedures significantly improve the color stability of Acetal resins clasps when being immersed incommonly consumed beverages.