Effect of Duodenogastric Reflux on Dental Enamel.

PURPOSE: To evaluate the effects of stomach and duodenal fluid on enamel surfaces, simulating the action of refluxed liquid in patients with duodenogastric reflux. METHODS AND MATERIALS: Forty bovine incisors were used to obtain enamel fragments. Only half of the enamel surface was exposed to erosive challenges; the samples were then randomly divided into the following four groups (n = 10): G1: HCl; G2: HCl + pepsin; G3: HCl + ox bile + NaHCO3; and G4: HCl + pancreatin + NaHCO3. The specimens were placed in 37°C solutions, six times per day, for 20 s, over a period of 5 days and then analysed for morphology, surface roughness and the step formed on the dental enamel using confocal laser microscopy. The data were analysed using the Kruskal-Wallis and Dunn's test (p <0.05). RESULTS: Both analyses revealed a higher step and surface roughness for the G3 group (5.6 µm ± 1.69, 2.2 µm ± 1.61), which were statistically significant compared with the G1 and G2 groups (3.9 µm ± 1.5 µm; 1.0 µm ± 0.18; 3.7 µm ± 1.45; and 0.9 µm ± 0.12) (p <0.05); only the step in the G4 group (4.9 µm ± 1.8 µm) was similar to that of the G3 group (p >0.05). Morphological analysis showed greater structural loss in the G3 and G4 groups. CONCLUSIONS: Bile and pancreatin, in combination with hydrochloric acid, may promote a greater loss of structure, increased surface roughness and loss of enamel prismatic anatomy.

Efficacy of different strategies to treat root dentin eroded by liquid or gaseous hydrochloric acid associated with brushing abrasion.

OBJECTIVE: This study aims to evaluate how casein phosphopeptide-amorphous calcium phosphate (CPP-ACP) associated with Nd:YAG or Diode laser affects dentin exposed to hydrochloric acid (HCl) with or without tooth brushing. DESIGN: One hundred and sixty human root dentin blocks were selected after they were initially eroded with liquid HCl (pH 1.2) 3x for one day. The blocks were divided into the following groups: G1- liquid HCl (HCl-l), G2- HCl-l + brushing, G3- gaseous HCl (HCl-g), and G4- HCl-g + brushing. Each group was randomly assigned to the following treatments (n = 10): A) Control (no treatment), B) CPP-ACP, C) CPP-ACP associated with Nd:YAG laser (λ = 1064 nm) (40 mJ, 10 Hz, 0.4 W, 15 s), and D) CPP-ACP associated with Diode laser (λ = 980 nm) (0.5 W, 200 µs, 15 s). The treatment with CPP-ACP (G2, G3 and G4) was applied on the dentine surface for 5 min. Erosion (6x/day/20 s) and erosion (6x/day/20 s) with abrasion (2x/10 s) were performed for five days. Dentin volume loss was determined by 3D confocal laser microscopy. Data were analyzed with two-way ANOVA and Tukey's tests. RESULTS: G1 - CPP-ACP (10.77 ±â€¯1.66) and CPP-ACP associated with Diode laser (9.98 ±â€¯0.89) showed lower volume loss in relation Control group (12.86 ±â€¯0.63) (p < 0.05). G2 - CPP-ACP associated with Diode laser (12.41 ±â€¯1.08) elicited lower volume loss as compared to the Control (14.42 ±â€¯1.24) (p < 0.05). As for G3 and G4, all treatments showed similar volume loss. CONCLUSION: CPP-ACP and CPP-ACP associated with Diode laser could control dental tissue loss in dentin eroded by liquid HCl. Moreover, CPP-ACP associated with Diode laser could effectively decrease dental tissue loss in dentin exposed to liquid HCl and brushing.