Debonding force and shear bond strength of an array of CAD/CAM-based customized orthodontic brackets, placed by indirect bonding- An In Vitro study

PLoS One. 2018 Sep 11;13(9):e0202952. doi: 10.1371/journal.pone.0202952. eCollection 2018.

Abstract

Based on three-dimensional scanning and computer-aided design and computer-aided manufacturing (CAD/CAM) techniques, customized bracket systems are increasingly used. However, data remain limited regarding customized bracket design, characteristics, and stability. This study was undertaken to evaluate the design, bond strength, and residual adhesives of four different CAD/CAM customized brackets that were attached to human tooth specimens by indirect bonding. Thirty extracted human upper premolars were divided into five groups: Group 1, preadjusted self-ligating labial metal bracket; Group 2, lingual self-ligating metal injection molding customized bracket; Group 3, gold-casted lingual customized bracket; Group 4, labial self-ligating milled customized bracket; Group 5, labial customized resin base bracket. Except in Group 1, premolar specimens were scanned via model scanner, and the images were sent to each manufacturing company to fabricate customized brackets and transfer trays/jigs. Debonding force (DF; N) was measured by Instron universal testing machine and shear bond strength (SBS; MPa) was calculated via dividing DF by bonding area. Adhesive remnants were analyzed via stereo microscopic images. Group 2 (196.90±82.75 N) exhibited significantly higher DF than Group 1 (62.77±12.65 N); other groups exhibited similar DFs, compared with Group 1. No customized bracket groups exhibited significant differences in SBS, relative to Group 1 (6.73±1.36 MPa). However, SBS in Group 5 (11.46±7.22 MPa) was significantly higher than in Group 3 (3.58±2.14 MPa). Group 3 had significantly lower ARI scores than other groups (P<0.05). Customized brackets exhibited large deviations in DF and SBS; all customized bracket systems exhibited DF that was equivalent or superior to that of preadjusted brackets, even when placed by indirect bonding.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Bicuspid
  • Computer-Aided Design*
  • Dental Bonding*
  • Dental Stress Analysis
  • Humans
  • Materials Testing
  • Microscopy, Electron, Scanning
  • Orthodontic Brackets*
  • Resin Cements
  • Shear Strength

Substances

  • Resin Cements

Grants and funding

This research was supported by a grant (16172MFDS335) from the Korea Ministry of Food and Drug Safety in 2016 (http://mfds.go.kr/eng/index.do) and by Advanced Technology Center Program (No.10077361), 'Integrated System for Dental Diagnosis, Treatment Simulation & PSI(Patient Specific Instrument) Design' from the Ministry of Trade, Industry & Energy, MOTIE, Korea (www.motie.go.kr/). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.