Dentine bond strength of fluoride-containing dental adhesives: a systematic review

Abstract

Objectives: Purpose of this review was to investigate the fluoride release/uptake and bond strength of fluoride-containing dental adhesives. Methods: Information from scientific reviews (n=20) and original papers (n=115) with search titles (“fluoride” or “fluorine”) AND (“dental adhesives”, “restorative materials” or “dentine bonding agents”), published between 1990 and June 2016 (PubMed and Scopus) were included. Articles covering orthodontic materials, endodontic materials, resin composites, compomers, giomers, or GICs were excluded. Ultimately, 24 original articles were selected and reviewed by first two authors following PRISMA statement. Results: Articles included in this review followed non-unified study protocol and give contradictory results. Based on these articles a proper systematic review approach cannot be followed. Accordingly, we can only report that: (1) Fluoride-containing dental adhesives (F-dental adhesives) release various levels of fluoride in vitro due to factors, majorly the composition of adhesive, type of fluoride filler contents (e.g. NaF, F-glass, pre-reacted GI fillers (PRG)) and experimental environment (e.g. distilled water, phosphate buffer solution and artificial saliva) affect the degree of fluoride release. (2) Only two studies regarding µTBS tests of fluoride containing dental adhesives, which all showed that F-dental adhesives achieved a weaker initial bond than non-fluoride dental adhesives, but the bond of F-dental adhesives after 3 months of storage was found to be significantly higher than the non-fluoride ones. Whether the fluoride release from adhesives affect the dentine bonding quality is still substantiated. (3) 12 studies determined fluoride release using Ion selective electrode method and only 1 study has used ion chromatography. Conclusions: The use of fluoride in dental adhesive to improve dentine bond strength is still questionable. A standardized approach must be followed to show fluoride effect on µTBS and amount of fluoride ion release in storage media for clear understanding.