Effect of Erosive pH Cycling on Different Restorative Materials and on Enamel Restored with These Materials

Abstract

The different types of restorative materials tested were not able to protect adjacent enamel from erosion. Thus, the ability of a restorative material to prevent tooth erosion should not be considered when choosing a material. SUMMARYThis in vitro study evaluated the effect of erosive pH cycling on the percentage of surface microhardness change (%SMHC) and wear of different restorative materials and bovine enamel restored with these materials. Eighty enamel specimens were randomly divided into eight groups according to the restorative materials and immersion media used: GI/GV-resin-modified glass-ionomer, GII/GVI-conventional glassionomer, GIII/GVII-resin composite and GIV/GVIII-amalgam. Over a period of seven days, groups GI to GIV were immersed in a cola drink (ERO) for 5 minutes, 3x/day and kept in artificial saliva between erosive cycles. Groups GV to GVIII were immersed in artificial saliva (SAL) throughout the entire experimental period (control). Data were tested for significant differences using ANOVA and Tukey's tests (p<0.05). For %SMHC, considering the restorative materials, no significant differences were detected among the materials and immersion media. Mean wear was higher for the resin modified glass ionomer cement when compared to conventional cement, but those materials did not significantly differ from the others. For enamel analyses, erosive pH cycling promoted higher wear and %SMHC compared to saliva. There were no significant differences in wear and %SMHC of enamel around the different restorative materi-

Optical coherence tomography for evaluation of enamel and protective coatings

“…4), the coating layer appeared to be fractured. Such voids and cracks have been attributed to the continuous internal acid-base reactions known for glass ionomers 38) ; and could also be due to the effect of the acidic environment on the integrity of material 39) . On the other hand, anti-caries effects of RMGIs were attributed to the presence of the loosely-bound fluoride ions from the glass fillers, which are free to move and protect enamel surface 15) .…”

Effects of erosive challenge on the morphology and surface properties of luting cements

“…Some studies have shown that the erosive degradation of cements depends on the immersion time 18 , the type of beverage 12,14 and the acidity of the media 18 . It is known that during consumption, a beverage contacts the tooth surface and dental materials for only a short duration before it is washed away by saliva 19 .…”

“…The phosphoric acid found in the cola beverage could induce the softening of dimethacrylate and Bis-GMA polymers 14 and could favor the displacement of inorganic fillers, contributing to the formation of rough surfaces. This fact could also be associated with the decrease in VHN values found after erosive challenge for resin-based luting cements (Table 3).…”

“…In addition, the percentage of microhardness loss (% VHN) was calculated using the following formula 14 :…”

“…However, to simulate erosive development caused by the daily ingestion of acidic beverages, in vitro studies have used dynamic erosive challenge with daily cycles of immersion in acidic beverages and artificial saliva [13][14][15] .…”