Cavity preparation devices: effect on microleakage of Class V resin-based composite restorations.
OBJECTIVE
To evaluate the effect of cavity preparation device (i.e. carbide bur, diamond bur, air abrasive, Sonicsys, and Er:YAG laser) on microleakage of Class V resin-based composite (RBC) restorations, the tooth restoration interface and dentin ultrastructure.


METHODS
Eight groups (n=18) of 9 human molars each were prepared on the buccal and lingual surfaces for Class V RBC restorations using five preparation devices: Group 1: carbide bur #8 round; Group 2: diamond bur #801; Group 3: KCP 1000 air abrasion unit; Group 4: Sonicsys Approx.; Group 5: Er:YAG laser; Group 6: carbide bur plus air abrasive; Group 7: carbide bur plus laser, and Group 8: laser without etching. Circular cavity preparations, 3 mm diameter and 1.5 mm deep, were cut at the CEJ on the buccal and lingual surfaces of each tooth. A bevel was placed on the enamel margin. All cavities were restored using Single Bond adhesive system and Silux Plus according to manufacturer's directions, with the exception that no etchant was used with Group 8. After thermocycling, specimens were tested for microleakage using silver nitrate methodology. Dye penetration data was collected and subjected to non-parametric statistical analysis. SEM analysis of the dentin-RBC interface, as well as the effect of each cavity preparation device on the surface of dentin was performed.


RESULTS
Microleakage did not occur in enamel for any method of cavity preparation when the enamel was etched prior to adhesive application. Kruskal-Wallis One-way ANOVA revealed differences in dentin microleakage among the tested groups at alpha=0.05. Mann-Whitney Test for Paired Comparisons at alpha=0.01 demonstrated significantly greater dentin microleakage in Groups 5 and 7 compared to all groups except Group 3 (air abrasive). Although Group 8 had the least microleakage in dentin, this was not significantly different from Groups 1, 2, 4 and 6. SEM observation revealed hybridization at the dentin-resin interface for all groups except for Group 8 (laser prepared, non-etched). Surface analysis showed differences related to the operating mode of each preparation device.


CONCLUSIONS
The method of cavity preparation did not affect microleakage in etched enamel. When using a laser for cavity preparation, enamel should be etched although not etching dentin may help to improve marginal seal.
Setien
V J
VJ
University of the Andes, Merida, Venezuela. vsetien@blue.weeg.uiowa.edu
Cobb
D S
DS
Denehy
G E
GE
Vargas
M A
MA
D000134:Acid Etching, Dental; D000388:Air; D000704:Analysis of Variance; D017438:Bisphenol A-Glycidyl Methacrylate / Q000737:chemistry; D017554:Carbon Compounds, Inorganic; D003188:Composite Resins / Q000737:chemistry*; D001840:Dental Bonding; D003737:Dental Cavity Preparation / Q000295:instrumentation*; D003743:Dental Enamel / Q000648:ultrastructure; D003763:Dental Leakage / Q000145:classification*; D003793:Dental Restoration, Permanent / Q000145:classification*; D003804:Dentin / Q000648:ultrastructure; D017220:Dentin-Bonding Agents / Q000737:chemistry; D018130:Diamond; D004867:Equipment Design; D006801:Humans; D007834:Lasers; D008855:Microscopy, Electron, Scanning; D016622:Silver Staining; D018709:Statistics, Nonparametric; D013499:Surface Properties; D013816:Thermodynamics; D019237:Tooth Cervix / Q000648:ultrastructure
D017554:Carbon Compounds, Inorganic; D003188:Composite Resins; D017220:Dentin-Bonding Agents; C115612:single bond; C074741:Silux Plus; D017438:Bisphenol A-Glycidyl Methacrylate; D018130:Diamond