Developmental oronasal fistula of the incisive papilla.

Various terms (including patent nasopalatine fistula and patent nasopalatine duct) have been used to describe the presence of a developmental fistulous tract that connects the oral and nasal cavities through an oral opening located at the incisive papilla. Reportedly, this condition is a rare developmental variant; approximately 40 cases have been reported in the literature. Because awareness of this entity is important to avoid misdiagnosis, this article presents the clinical and conebeam computed tomography findings of two cases. Based on a review of the development of the nasopalatine structures in man, the authors propose that this entity be classified as a developmental oronasal fistula of the incisive papilla.

Bond strength of composite to dentin and enamel using self-etching adhesive systems.

To determine the shear bond strength of 10 self-etching adhesive systems to dentin and enamel, flat bonding sites were prepared on 216 extracted human molar teeth, using 600-grit silicon carbide paper to expose dentin or enamel. Following the application of each adhesive system, bonded assemblies of Spectrum TPH were prepared using a gelatin capsule matrix (n = 24). After 24 hours of storage in water at 37 degrees C, 12 specimens from each enamel and dentin group were debonded. This was followed by thermocycling for 6,000 cycles between water baths at 5 degrees C and 55 degrees C, with a dwell time of 20 seconds in each bath. Specimens were loaded to failure in a testing machine with a crosshead speed of 5 mm/minute. Statistical analysis included a one-way ANOVA and least square difference post hoc test. There were significant differences in shear bond strength for both enamel and dentin among the materials tested (p < 0.05).