Cells and Materials


The strength of adhesion between dental calculus and enamel or dentin surfaces determines the ease with which the calculus can be removed by brushing or professional dental treatment. In this study, we examined the adhesion of canine calculi formed on substrata with different surface free energies (sfe) and roughness by means of scanning electron microscopy. In 4 beagle dogs fenestrated crowns were made on the upper fourth premolars. Subsequently, facings of glass (sfe = 120 mJ. m-2), bovine enamel (sfe = 85 mJ.m-2), bovine dentin (sfe = 92 mJ.m-2), polymethyl-methacrylate (PMMA, sfe = 56 mJ.m-2) and polytetrafluorethylene (PTFE, sfe = 20 mJ. m-2) were inserted in the crowns for 1, 3, 7, 14 or 28 days. After removal from the oral cavity the samples were fixed with glutardialdehyde and Os04, freeze-dried and fractured prior to scanning electron microscopical examination. On low sfe substrata, as PTFE and PMMA, a larger distance was observed between the calculus mass and substratum than observed for high sfe substrata, as glass, enamel and dentin. In addition, the fracture was mainly of interfacial character on the low sfe substrata and cohesive in the calculus mass for the high sfe substrata. These observations support previous findings that calculus removal by brushing or ultrasonic treatment is easier from low sfe substrata.