IADR Abstract Archives
In Vitro Evaluation of Monomer Release From Fixed Retainers
Objectives: The adhesives used to bond orthodontic retentions are low-loaded composite resins with a resinous matrix. Fixed lingual retainers, used in orthodontics since the 1970s, are bonded to the anterior mandibular teeth to prevent relapse or secondary crowding.
The aim of this study was to generate a reproducible protocol for the in vitro evaluation of the release of monomers from orthodontic retainers.
Methods: We realized a retention model with calibrated molds (diameter: 4 mm, height: 1.5 mm). For each sample, 6 dots of composite representing the 6 anterior teeth were placed. Each dot was cured using a curing light (ScanWave Mini LED®, Acteon) with a power of 1500+/- 10% mW per square centimeter and a wavelength of radiant energy between 390 and 510 nm for 20 seconds. Each cured sample is immersed in MilliQ water (ISO 10993-12 standard) contained in a glass tube for 24 hours at 37 ° C. The analysis of the eluates composition was performed by GC-MS (gas chromatography - mass spectrometry).
Results: The qualitative and quantitative evaluation of the in vitro release of monomers from orthodontic adhesives is possible with this model. Peaks in the chromatogram correspond to mass spectra. The compounds found are mostly monomers or their derivatives, and additives. No BPA was detected. A greater release of TEGDMA from fluid orthodontic adhesives was detected. Toxic components were also identified (iodobenzene, iodobiphenyl, triphenyl stibine, etc.).
Conclusions: The probability of release of TEGDMA is strong. No trace of BPA has been identified in this orthodontic resin. It would be appropriate to consider composite resins without TEGDMA, Bis-GMA or toxic compounds to bond orthodontic retainers, especially in children and adolescents.
The aim of this study was to generate a reproducible protocol for the in vitro evaluation of the release of monomers from orthodontic retainers.
Methods: We realized a retention model with calibrated molds (diameter: 4 mm, height: 1.5 mm). For each sample, 6 dots of composite representing the 6 anterior teeth were placed. Each dot was cured using a curing light (ScanWave Mini LED®, Acteon) with a power of 1500+/- 10% mW per square centimeter and a wavelength of radiant energy between 390 and 510 nm for 20 seconds. Each cured sample is immersed in MilliQ water (ISO 10993-12 standard) contained in a glass tube for 24 hours at 37 ° C. The analysis of the eluates composition was performed by GC-MS (gas chromatography - mass spectrometry).
Results: The qualitative and quantitative evaluation of the in vitro release of monomers from orthodontic adhesives is possible with this model. Peaks in the chromatogram correspond to mass spectra. The compounds found are mostly monomers or their derivatives, and additives. No BPA was detected. A greater release of TEGDMA from fluid orthodontic adhesives was detected. Toxic components were also identified (iodobenzene, iodobiphenyl, triphenyl stibine, etc.).
Conclusions: The probability of release of TEGDMA is strong. No trace of BPA has been identified in this orthodontic resin. It would be appropriate to consider composite resins without TEGDMA, Bis-GMA or toxic compounds to bond orthodontic retainers, especially in children and adolescents.