Calcium phosphates as fillers for methacrylate-based sealer.

OBJECTIVES: The aim of this study was to evaluate the mineral deposition, push-out bond strength, radiopacity, the degree of conversion, film thickness, flow, calcium ion release, and pH of experimental endodontic sealers containing hydroxyapatite (HAp), aflfa-ticalcium phosphate (α-TCP), or octacalcium phosphate (OCP) particles. MATERIALS AND METHODS: Fifty single straight root human premolars were instrumented and divided into five groups (n = 10). Experimental endodontic sealers were formulated by 70 wt% urethane dimethacrylate (UDMA), 15 wt% of glycerol-1,3-dimethacrylate (GDMA), 15 wt% of ethoxylated bisphenol A glycol dimethacrylate (BISEMA), camphorquinone (CQ), N,N-dihydroxyethyl-para-toluidine (DHEPT), and benzoyl-peroxide. 10 wt% of each HAp, α-TCP, or OCP were added to the resin and its properties were assessed. RESULTS: After 7 days, the degree of conversion ranged from 44.69% (GOCP) to 50.74% (Gcontrol) and no statistical difference were observed (p < 0.05). GAHplus showed the highest push-out bond strength 4.91 (± 2.38) MPa at 28 days of analysis (p < 0.05). Film thickness and pH were not statistically different (p > 0.05). Statically lower values of flow were found for GHAp, GOCP, and Gα-TCP (p < 0.05). Calcium deposition values were higher for GHAp at 28 days. CONCLUSIONS: Bond strength, degree of conversion, and film thickness of endodontic sealers with phosphates showed similar results compared with AHplus, but displayed higher amounts of Ca2+ release. CLINICAL RELEVANCE: Phosphate fillers improve the performance of endodontic sealers after 28 days of simulated body fluid.

Influence of mouthwashes on the physical properties of orthodontic acrylic resin

AIM: The aim of this study was to evaluate the influence of acrylic resin immersion in different mouthwashes on hardness, roughness and color. METHODS: Specimens of an orthodontic self-cured acrylic resin (Orto Clas(r)) were produced and immersed in five mouthwashes: Plax(r) Classic (Colgate(r)); Plax(r) alcohol-free (Colgate(r)); Listerine(r) (Johnson & Johnson(r)); Periogard(r) (Colgate(r)) and Periogard(r) alcohol-free (Colgate(r)). Nine different immersion times were studied: 1, 2, 4, 6, 8, 10, 12, 24 h and 7 days, totalizing 45 groups. The specimens were evaluated before and after immersion by Knoop microhardness (n=5), roughness in Ra parameter (n=5), and colorimetric analysis, CIElab (n=3). RESULTS: All mouthwashes softened the acrylic resins after 7 days of immersion. PlaxÒ alcohol-free showed no statistically significant difference of softening between the immersion times. Listerine(r) showed softening after immersion at all times. Plax(r) alcohol-free and Listerine(r) showed significantly increased values of roughness after 12 h of immersion (p<0.05). Listerine(r) presented a significant increase in color variation after 12 h of immersion. CONCLUSIONS: Immersion in mouthwashes could influence acrylic resin hardness, roughness and color...