Hypersensitive dentin: testing of procedures for mechanical and chemical obliteration of dentinal tubuli.

This study examined by scanning electron microscopy the effect of various mechanical and chemical procedures in obliterating dentinal tubuli. Dentin blocks containing open, cross-sectioned dentinal tubuli were separated into one experimental and one control area. The mechanical treatments consisted of 20 seconds of continuous instrumentation with sharp and dull curets, finely textured inserts for the EVA reciprocating handpiece, metal and plastic inserts for a sonic scaler, and metal inserts for an ultrasonic scaler. Chemical treatments included a light-cured dental resin and active obliterating agents including sodium, stannous and hydrogen fluorides, potassium oxalate, glycerin, ferric oxalate, and potassium nitrate. These substances were applied to the test surfaces for 2 minutes and allowed to dry. One half of the chemically treated specimens were then sprayed with water in order to evaluate the retention of the obliterating agents. The results revealed that among the mechanical treatments, the sharp curet gave the most consistent and complete obliteration of the tubuli. The plastic inserts had no tubular occluding effects. Among the chemical procedures, the light-cured resin resulted in the most complete obliteration of the tubuli, while the fluoride agents and glycerin had no effect. It can be hypothesized that combining instrumentation with a sharp curet causing a heavy smear layer and occlusion of tubuli apertures, followed by application of a light body resin, may prove to be a rational method of desensitizing hypersensitive dentin surfaces. However, this combined treatment should be evaluated in clinical trials.