EFFECTS OF CAVITY PREPARATION USING A NANOSECOND-PULSED ND-YAG LASER ON TOOTH-RESTORATION INTERFACE

This study evaluated the tooth-restoration interface between composite resin or glass ionomer cement and the tooth surface in teeth where ca ries removal and cavity preparation were performed either with the den tal drill, the dental drill and laser irradiation, or laser irradiatio n alone. A nanosecond-pulsed Nd-YAG; laser was used at energy densitie s of 2-8 J cm(-2). After tooth restoration, microleakage tests were pe rformed using methylene blue. Using general linear model procedures, n o significant differences in microleakage were determined between 'dri ll' and 'drill and laser'-prepared groups (p<0.01) in resin- and in gl ass-ionomer-restored teeth. These specimens showed significantly less dye penetration than the 'laser only' group (p<0.0001). No correlation was found between fluence and microleakage using either restorative m aterial (p=0.8). Dye penetration was significantly greater in the comp osite-filled than in the glass-ionomer group (p<0.05). Mechanisms infl uencing laser effects on bonding require further investigation before clinical application of lasers as an alternative to the dental drill c an become viable.