Release of bisphenol A and its derivatives from orthodontic adhesive systems available on the European market as a potential health risk factor.

INTRODUCTION: Treatment with fixed orthodontic appliances requires the application of adhesive systems to enable secure fastening of brackets and retainers to the surface of tooth enamel. The orthodontic bonding systems are similar in terms of chemical composition to dental filling materials, the chemical stability of which is not satisfactory. Particularly alarming is the release of bisphenol A and its derivatives to the external environment, which has been well-documented for materials used in conservative dentistry. OBJECTIVES: The aim of the study was an in vitro assessment of the release of biologically harmful bisphenol A and its derivatives from orthodontic adhesives available on the European market, as a potential health risk factor for orthodontic patients. MATERIAL AND METHODS: The study assessed levels of BPA, BPA polymers and Bis-GMA resin in eluates of six commonly used orthodontic adhesives: Light Bond, Transbond XT, Resilence, Aspire, GrenGloo and ConTec LC, obtained after one hour, 24 hours, 7 days and 31 days of material sample storage in water. The presence and concentration of the studied chemicals in the obtained solutions were identified using the HPLC method. RESULTS: The highest (p≤0.05) concentration of BPA at 32.10µg/ml was observed in the Resilence material eluates. The highest concentration of poly-bisphenol A was found in solutions obtained after incubation of ConTec LC adhesive at 371.90µg/ml, whereas the highest amount of Bis-GMA resin (425.07µg/ml) was present in Aspire material eluates. CONCLUSIONS: 1) In conditions of the current experiment it was demonstrated that most of the assessed orthodontic adhesive resins available on the European market and released into the outside environment - biologically harmful bisphenol A or its derivatives, posing a potential threat to the patients' health. 2) Release of BPA and its derivatives into aqueous solutions is the highest in the early stages of sample incubation.

[Dentinal hypersensivity after vertical stripping of enamel]. / Ocena wrazliwosci zebiny po szlifowaniu pionowym szkliwa.

INTRODUCTION: Vertical stripping of enamel in patients with minor or moderate crowding of teeth and Angle's class I is an effective method which supplements orthodontic treatment. Stripping is an alternative to tooth extraction or to extension of alveolar arches which carries the risk of recurrence of crowding and further periodontal difficulties. Stripping also shortens considerably the duration of treatment. Apart from unquestionable advantages, enamel reduction may lead to complications such as caries or hypersensitivity of interproximal surfaces of stripped teeth. The aim of this study was to determine the prevalence of hypersensitivity and to measure the intensity of pain. MATERIALS AND METHODS: We performed a verbal and visual assessment of pain in a group of 32 patients who underwent stripping during the recent few years as part of orthodontic treatment. RESULTS: According to verbal assessment, the highest percentage (46.9%) of patients rated their pain as 1 (gentle pain) which corresponded to 1-3 cm on the 10 cm Visual Analog Scale. 37.5% of patients reported no pain. CONCLUSION: None of the patients described their pain as very strong and discouraging from further treatment. All symptoms subsided without recurrence. The patients found this method to be more effective than alternative ones.