In vitro study of enamel and dentin marginal integrity of composite and compomer restorations placed in primary teeth after diamond or Er:YAG laser cavity preparation.
OBJECTIVE
The aim of this in vitro study was to evaluate the effect of laser vs diamond instruments on Class II and Class V cavity margins in primary teeth with SEM after restoration with composite and compomer materials and subsequent thermocycling.


METHODS
Class V cavities with margins completely located in enamel were prepared in 36 extracted primary teeth to examine the restoration-enamel interface. Eighteen cavities were prepared with an Er:YAG laser operated at 3 Hz, 300 mJ/pulse, and 18 with a spherical fine diamond bur. In 24 primary teeth, Class II cavities with cervical proximal margins located in dentin were prepared for examination of the restoration-dentin interface. All Class II cavities were prepared with a conventional cylindrical diamond bur. In 12 cavities, the margins located in dentin were conditioned with an Er:YAG laser (1 Hz, 100 mJ/pulse). All cavities were restored with a fine hybrid composite resin or a compomer material.


RESULTS
SEM examination of Class V cavities after thermocycling (between 5 degrees C and 55 degrees C, 2500 cycles) revealed over 90% "perfect" margins in all composite fillings and in those compomer restorations applied after conventional preparation and acid etching. Compomer restorations placed without acid etching revealed a significantly superior marginal integrity in laser-prepared cavities (81% perfect margins) vs conventionally prepared cavities (60% perfect margins). SEM analysis of the dentinal margins of both compomer and composite restorations in Class II cavities showed mean percentages of perfect marginal adaptation ranging from only 13% to 66%.


CONCLUSIONS
Er:YAG laser treatment can be recommended for composite restorations in Class V cavities in primary teeth. Compomer restorations can be placed after conventional preparation of Class V cavities and acid etching or after laser preparation. Dentin bonding in Class II cavities in primary teeth is not sufficient and cannot be improved with Er:YAG laser pretreatment.
Stiesch-Scholz
M
M
Department of Prosthetic Dentistry, Medical University of Hannover, Carl-Neuberg-Strasse 1, D-30625 Hannover, Germany. ms@prothetik.zmk.mh-hannover.de
Hannig
M
M
D000134:Acid Etching, Dental; D000538:Aluminum Silicates; D020770:Compomers / Q000737:chemistry*; D003188:Composite Resins / Q000737:chemistry*; D003737:Dental Cavity Preparation / Q000145:classification / Q000295:instrumentation / Q000379:methods*; D003743:Dental Enamel / Q000648:ultrastructure*; D018772:Dental Marginal Adaptation; D003793:Dental Restoration, Permanent / Q000145:classification / Q000379:methods; D003804:Dentin / Q000648:ultrastructure*; D017220:Dentin-Bonding Agents / Q000737:chemistry; D018130:Diamond; D004871:Erbium; D006801:Humans; D007834:Lasers; D008855:Microscopy, Electron, Scanning; D013223:Statistics as Topic; D018709:Statistics, Nonparametric; D013499:Surface Properties; D013816:Thermodynamics; D014094:Tooth, Deciduous / Q000648:ultrastructure*; D015019:Yttrium
D000538:Aluminum Silicates; D020770:Compomers; D003188:Composite Resins; D017220:Dentin-Bonding Agents; C113300:TPH hybrid; D015019:Yttrium; D018130:Diamond; D004871:Erbium