IADR Abstract Archives
Effects of Lithothamnion Calcareum Incorporation on a Methacrylate-Based Orthodontic Resin
Objectives: Several studies in our laboratory demonstrated that, even at low concentration (0.03%), the aqueous solution of Lithothamnion Calcareum (LC) prevents enamel demineralization as (or more) efficiently as fluorides. Preliminary experiments also indicated that LC fairly inhibited S. mutans growth. Thus, we hypothesized that LC could help reducing the risk of enamel demineralization around the interface enamel-orthodontic-bracket. This study assessed the effect of LC on a methacrylate-based orthodontic resin degree of conversion (%DC), water sorption (WS), solubility (SL) and ability to prevent enamel demineralization following pH-challenge.
Methods: The orthodontic adhesive TransBond-XT (3M) was added with 2% LC powder. Pristine TransBond-XT was used as control. The %DC was measured using an ATR-FTIR approach (n=3/group). Disc-like specimens (13.5x2.5mm thick) were prepared for WS and SL measurements (n=5/group). Twenty de-identified caries-free human molars were sectioned longitudinally into 2 halves, cleaned with fluoride-free paste, rinsed, and treated with TransBond-XT primer. Metallic brackets were bonded to half of samples with TransBond-XT and the other half with TransBond-XT+LC. Samples were submitted to pH-challenge cycling, staying 6hrs in demineralization solution (pH4.5) and 18hrs in remineralization solution (pH7.4). Between one and another solution, samples were 5-minute incubated in either water or 0.03% LC (n=10/group). This procedure was repeated for 14 days. Enamel at the interface with bonded bracket was assessed by tactile and visual (stereoscope-4X) analyses. Data were analyzed by ANOVA and Tukey tests (α=0.05).
Results: LC addition did not affect TransBond-XT %DC. WS and SL were significantly lower and higher for TransBond-XT+LC compared to TransBond-XT, but values met the ISO-4049 requirements (Figure1). No difference was detected by tactile analysis of enamel at its interface with bonded brackets. Conversely, white-spot lesions were visually seen in 7 of 10 samples bonded with TransBond-XT and not exposed to LC solution, which was not observed in TransBond-XT+LC-treated samples.
Conclusions: LC enhanced the ability of an orthodontic methacrylate-based adhesive at preventing enamel demineralization following pH-challenge.
Methods: The orthodontic adhesive TransBond-XT (3M) was added with 2% LC powder. Pristine TransBond-XT was used as control. The %DC was measured using an ATR-FTIR approach (n=3/group). Disc-like specimens (13.5x2.5mm thick) were prepared for WS and SL measurements (n=5/group). Twenty de-identified caries-free human molars were sectioned longitudinally into 2 halves, cleaned with fluoride-free paste, rinsed, and treated with TransBond-XT primer. Metallic brackets were bonded to half of samples with TransBond-XT and the other half with TransBond-XT+LC. Samples were submitted to pH-challenge cycling, staying 6hrs in demineralization solution (pH4.5) and 18hrs in remineralization solution (pH7.4). Between one and another solution, samples were 5-minute incubated in either water or 0.03% LC (n=10/group). This procedure was repeated for 14 days. Enamel at the interface with bonded bracket was assessed by tactile and visual (stereoscope-4X) analyses. Data were analyzed by ANOVA and Tukey tests (α=0.05).
Results: LC addition did not affect TransBond-XT %DC. WS and SL were significantly lower and higher for TransBond-XT+LC compared to TransBond-XT, but values met the ISO-4049 requirements (Figure1). No difference was detected by tactile analysis of enamel at its interface with bonded brackets. Conversely, white-spot lesions were visually seen in 7 of 10 samples bonded with TransBond-XT and not exposed to LC solution, which was not observed in TransBond-XT+LC-treated samples.
Conclusions: LC enhanced the ability of an orthodontic methacrylate-based adhesive at preventing enamel demineralization following pH-challenge.
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