Safety and antibacterial properties of controlled release SnF2

Two clinical studies were performed to evaluate the safety and efficacy of an intracoronal device for the controlled release of SnF2. SnF2-polycarboxylate cement, containing approximately 72 mg F-, was placed in subjects' molars requiring two-surface restorations. In the trial for safety, eight subjects had the restoration in place for 34 days. The salivary fluoride levels were elevated to a mean of 0.3/10(6) over the experimental period. Urinary fluoride levels were only above baseline levels during the first few days. The restoration's physical properties were adequate; however, subjects experienced gingival irritation in areas where the restoration was contacted with gingiva. In the trial for efficacy, fourteen subjects had either a SnF2-polycarboxylate or a placebo restoration placed in a molar tooth during a 2 week period of no oral hygiene. During the experimental period, the control subjects had higher levels of salivary total CFU, Streptococcus sanguis and Streptococcus mutans: while the subjects with the SnF2 restoration had increased S. sanguis and decreased S. mutans levels. No differences in G.I. or PL 1 scores were noted between groups. Further development of this controlled release system should include using the SnF2-polycarboxylate restoration in more than one tooth per subject to increase the fluoride reservoir, and not allowing the restoration to contact gingival tissues.