Slow release fluoride glass devices in the prevention of enamel demineralisation during fixed appliance orthodontic treatment.

Enamel demineralisation or white spot lesions (WSLs) is a risk for all patients undergoing fixed appliance orthodontic treatment (FAOT) with no consensus with regards to prevalence, risk factors, prevention and treatment. Slow-release fluoride glass devices (SRFGDs) have been shown to clinically prevent caries without relying on patient’s compliance, therefore their effectiveness in preventing WSLs during FAOT was investigated. An in-vitro exploratory study investigated fluoride (F) and phosphate (PO4) release from different types of powder from SRFGDs incorporated into a composite resin bonding material. Samples were stored in artificial saliva and assessed with ion chromatography for up to six months. Three types of powder showed high F release to maximise caries prevention and low PO4 release to minimise degradation of powder. A questionnaire was emailed to orthodontists’ members of the British Orthodontic Society. For majority of responders the key factors to the problems related to WSLs are clinical examination, photographs, F, oral hygiene, diet and duration of FAOT. A double-blind, randomised clinical study with orthodontic patients randomly allocated to SRFGDs or placebo devices threaded onto the orthodontic wire was conducted. Cross-polarised digital photographs of the maxillary permanent central and lateral incisors and canines were taken for 63 subjects at the start and for 40 subjects at the end of the study. One examiner assessed photographs for presence and severity of WSLs. Majority of volunteers and the smallest number of refusals lived in the most deprived areas according to the Multiple Deprivation Index. Use of SRFGDs would decrease severity by preventing 2.88 times more teeth compared to use of 225 ppm F mouth-rinse once daily and 1,450 ppmF tooth-paste twice daily. Duration of FAOT and increased gingival index at the start of FAOT increased significantly the risk of developing WSLs. SRFGDs were effective in preventing teeth with WSLs during the course of FAOT.