title: Replacement of resin-based composite: evaluation of cavity design, cavity depth, and shade matching.
abstract: 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.
authors: Department of Operative Dentistry, University of Florida, College of Dentistry, Health Science Center, PO Box 100415, Gainesville, Florida 32610, USA. vgordan@dental.ufl.edu
authors: Valeria V
authors: VV
authors: Gordan
authors: Eduardo
authors: E
authors: Mondragon
authors: Chiayi
authors: C
authors: Shen
mesh_terms: 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
chemical_list: 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