title: Evaluation of the marginal and internal discrepancies of CAD-CAM endocrowns with different cavity depths: An in vitro study.
abstract: BACKGROUND
  The marginal and internal discrepancies of computer-aided design and computer-aided manufacturing (CAD-CAM) endocrowns are unknown.
  
  
  OBJECTIVE
  The purpose of this in vitro study was to evaluate the marginal and internal discrepancies of endocrowns with different cavity depths by measuring them with microcomputed tomography (μCT).
  
  
  METHODS
  Endocrowns (n=48) of 2 different cavity depths (2 mm and 4 mm) were fabricated in 2 different chairside CAD-CAM systems (CEREC AC and E4D). A μCT scan was made before and after cementation. For analysis of the marginal and internal discrepancies, reference points were selected in 2-dimensional views of 3 buccolingual cross-sections and 3 mesiodistal cross-sections. To calculate the total discrepancy volume, the μCT sections were reconstructed 3-dimensional views, and changes in volume and surface area were examined. Statistical analysis was performed using 2-way ANOVA with Bonferroni correction (α=.05).
  
  
  RESULTS
  An endocrown with a 4-mm cavity showed a larger marginal and internal volume than one with a 2-mm cavity. Cementation did not show significant differences in total discrepancy thickness. Discrepancies on the pulpal floor were largest in other sites. Both chairside CAD-CAM systems showed similar discrepancy in the endocrowns.
  
  
  CONCLUSIONS
  Based on the present study, marginal and internal discrepancies increased depending on cavity depth. Cementation did not increase the dimension of the discrepancy between the restoration and the cavity wall. The discrepancy on the pulpal floor appeared to affect these results.
authors.affiliation: Clinical Assistant Professor, Department of Conservative Dentistry, Oral Science Research Center, College of Dentistry, Yonsei University, Seoul, Republic of Korea.
authors.forename: Yooseok
authors.initials: Y
authors.lastname: Shin
authors.affiliation: Professor, Department of Conservative Dentistry, Oral Science Research Center, College of Dentistry, Yonsei University, Seoul, Republic of Korea.
authors.forename: Sungho
authors.initials: S
authors.lastname: Park
authors.affiliation: Professor, Department of Conservative Dentistry, College of Dentistry, Gangnam Severance Hospital, Yonsei University, Seoul, Republic of Korea.
authors.forename: Jeong-Won
authors.initials: JW
authors.lastname: Park
authors.affiliation: Professor, Department of Dental Biomaterials, College of Dentistry, Yonsei University, Seoul, Republic of Korea.
authors.forename: Kwang-Mahn
authors.initials: KM
authors.lastname: Kim
authors.affiliation: Professor, Department of Prosthodontics, College of Dentistry, Yonsei University, Seoul, Republic of Korea.
authors.forename: Young-Bum
authors.initials: YB
authors.lastname: Park
authors.affiliation: Professor, Department of Conservative Dentistry, Oral Science Research Center, College of Dentistry, Yonsei University, Seoul, Republic of Korea. Electronic address: operatys16@yuhs.ac.
authors.forename: Byoung-Duck
authors.initials: BD
authors.lastname: Roh
mesh_terms: D002484:Cementation; D017076:Computer-Aided Design; D003442:Crowns; D003737:Dental Cavity Preparation / Q000379:methods*; D018772:Dental Marginal Adaptation / Q000592:standards; D017267:Dental Prosthesis Design / Q000379:methods*; D006801:Humans; D066298:In Vitro Techniques; D011861:Radiography, Dental / Q000379:methods; D055114:X-Ray Microtomography