UC Irvine

This study evaluated the tooth-restoration interface between composite resin or glass ionomer cement and the tooth surface in teeth where caries removal and cavity preparation were performed either with the dental drill, the dental drill and laser irradiation, or laser irradiation alone. A nanosecond-pulsed Nd-YAG laser was used at energy densities of 2-8 J cm-2. After tooth restoration, microleakage tests were performed using methylene blue. Using general linear model procedures, no significant differences in microleakage were determined between 'drill' and 'drill and laser'-prepared groups (p < 0.01) in resin- and in glass-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 material (p = 0.8). Dye penetration was significantly greater in the composite-filled than in the glass-ionomer group (p < 0.05). Mechanisms influencing laser effects on bonding require further investigation before clinical application of lasers as an alternative to the dental drill can become viable.