Wedad Y Awliya, Khamis A Hassan.
In-vitro assessment of composite resin microhardness as affected by immersion in different beverage.
J Pak Dent Assoc Jan ;14(4):195-9.

OBJECTIVE: This study investigated the microhardness of a microfilled anterior composite resin material; Esthet-X as influenced by immersion in different beverages. MATERIALS AND METHODS: Twenty disc specimens (10 mm internal diameter and 2 mm thickness) were used. Vickers microhardness measurements were recorded after storage in artificial saliva. Specimens were randomly divided into four groups of 5 specimens each, according to the tested beverages; Regular Cola, Diet Cola, orange juice and distilled water (control). Control specimens were kept in distilled water for 14 days throughout the experiment. For experimental specimens, a 14-day testing cycle was carried out. Experimental specimens were initially stored in distilled water for 24 hours, and then submitted to a five-minute immersion in the tested beverages five times daily, followed by microhardness measurements. Data were submitted to one-way ANOVA and Tukey`s HSD multiple range test (p<0.05). RESULTS: One-way ANOVA indicated significant change in microhardness among the different groups (p=0.000). Experimental specimens immersed in Regular Cola, Diet Cola and orange juice exhibited significant changes in microhardness from the control specimens immersed in distilled water (P=0.000). CONCLUSION: The present findings disclosed that all experimented beverages significantly decreased the microhardness of the tested composite resin material, where Regular Cola showed the least decrease in microhardness and orange juice exhibited the highest decrease. Regular Cola showed a significant difference in microhardness from Diet Cola and orange juice (P=0.012 & 0.009 respectively). Diet Cola and orange juice displayed no significant change in microhardness (P=1.000).

PakMediNet -Pakistan's largest Database of Pakistani Medical Journals - http://www.pakmedinet.com