title: Evaluation of margin angles of collarless metal ceramic restorations.
abstract: This study was designed to measure the porcelain margin angles of completed collarless metal ceramic restorations and determine if these angles correspond to the most frequently recommended porcelain margin angle of 90 degrees. A sample of 99 metal ceramic restorations with porcelain labial margins were evaluated. A 1.0 mm slice taken from the midfacial impression of each restoration was evaluated by tooth location with a stereomaster microscope and the angle of the labial porcelain margin was calculated. The comparison of margin angles by tooth location showed no statistical difference between the groups. Comparison of the average margin angle with the most suggested 90-degree angle was analyzed with a One-Sample t-test and found to be statistically significant (p = 0.000). Although the majority of dental schools teach the shoulder preparation for collarless metal ceramic restorations, only 43% of the restorations measured fell within 10 degrees of this standard.
authors.affiliation: Department of Veterans Affairs Medical Center, Augusta, Georgia, USA.
authors.forename: Deborah L
authors.initials: DL
authors.lastname: Dalvit
authors.forename: M Harry
authors.initials: MH
authors.lastname: Parker
authors.forename: Stephen M
authors.initials: SM
authors.lastname: Cameron
authors.forename: M Chad
authors.initials: MC
authors.lastname: Hawkins
authors.forename: John R
authors.initials: JR
authors.lastname: Agar
authors.forename: J Stephen
authors.initials: JS
authors.lastname: Brousseau
mesh_terms: D000704:Analysis of Variance; D001641:Bicuspid; D003442:Crowns; D003481:Cuspid; D003760:Dental Impression Materials / Q000737:chemistry; D003776:Dental Porcelain / Q000737:chemistry*; D017267:Dental Prosthesis Design; D006801:Humans; D007180:Incisor; D016876:Metal Ceramic Alloys / Q000737:chemistry*; D008963:Molar; D011145:Polyvinyls / Q000737:chemistry; D012833:Siloxanes / Q000737:chemistry; D013499:Surface Properties
chemical_list: D003760:Dental Impression Materials; D016876:Metal Ceramic Alloys; D011145:Polyvinyls; D012833:Siloxanes; C034183:vinyl polysiloxane; D003776:Dental Porcelain