Replacement of resin-based composite: evaluation of cavity design, cavity depth, and shade matching.
OBJECTIVE
The aim of this study was to evaluate the effect of different cavity designs, cavity depths, and shade matching on the dimensions of Class I resin-based composite preparations during replacement of the restoration.


METHODS
Forty Class I cavity preparations were prepared in extracted premolars. The occlusal depths varied from 1.5 to 2.5 mm. In 20 teeth, the buccal and lingual walls were perpendicular to the pulpal floor; in another 20, they were divergent to the pulpal floor. Impressions were made of all preparations. The cavities were restored with resin-based composite. All subgroups were further divided into another two subgroups (n = 5), in which half of the teeth were restored with shade that matched the tooth and the other half were restored with a resin composite that was three shades different from the tooth. After 168 hours in distilled water, the restorations were removed. New impressions were made, and a total of 80 stone casts were fabricated. The perimeter and area of the restorations were recorded with a video-based imaging system. The dimensions of the postoperative cavity preparations were compared to the initial cavity sizes.


RESULTS
The depth of the original cavity preparation had a statistically significant effect on the change in cavity dimension, as measured by area and perimeter. The 2.5-mm-deep cavities showed greater loss of tooth structure. No statistically significant difference was found for different cavity designs or shade matching.


CONCLUSIONS
Replacement of Class I resin-based composite restorations results in loss of tooth structure. The deeper the original cavity preparation, the greater the loss of tooth structure at the occlusal cavosurface margin during replacement.
Gordan
Valeria V
VV
Department of Operative Dentistry, University of Florida, College of Dentistry, Health Science Center, PO Box 100415, Gainesville, Florida 32610, USA. vgordan@dental.ufl.edu
Mondragon
Eduardo
E
Shen
Chiayi
C
D000704:Analysis of Variance; D001641:Bicuspid; D003116:Color; D003188:Composite Resins / Q000737:chemistry; D003737:Dental Cavity Preparation / Q000145:classification / Q000379:methods*; D003743:Dental Enamel / Q000033:anatomy & histology; D003761:Dental Impression Technique; D003775:Dental Polishing; D003782:Dental Pulp / Q000033:anatomy & histology; D003793:Dental Restoration, Permanent; D017220:Dentin-Bonding Agents / Q000737:chemistry; D006801:Humans; D007091:Image Processing, Computer-Assisted; D007101:Immersion; D018715:Microscopy, Video; D003765:Models, Dental; D019279:Resin Cements / Q000737:chemistry; D019233:Retreatment; D012822:Silicon Dioxide; D016037:Single-Blind Method; D013223:Statistics as Topic; D013499:Surface Properties; D014867:Water / Q000737:chemistry; D015040:Zirconium
D003188:Composite Resins; D017220:Dentin-Bonding Agents; C099128:Prodigy; D019279:Resin Cements; C084018:Scotchbond Multi-Purpose; C083568:Z100 composite resin; D014867:Water; D012822:Silicon Dioxide; D015040:Zirconium