title: The relationship between base dimensions, force to failure, and shear bond strengths of bondable molar tubes.
abstract: OBJECTIVE
  To compare forces versus failure and shear bond strengths, and to explore their association with the base dimensions of four currently available bondable molar tubes.
  
  
  METHODS
  Tubes were bonded to hydroxyapatite discs using a conventional light-cured adhesive and were tested to shear failure with the Instron Universal testing machine. Results were analyzed using the Kruskal-Wallis test and regression and survival analyses.
  
  
  RESULTS
  No statistical difference was observed between the four groups globally in terms of force to failure (P  =  .059) and bond strength (P  =  .179). However, regression analysis showed that each 1 mm(2) increase in base surface area required an additional force of 3.11 N to debond the tube. Survival analysis showed that the tube with the greatest base dimensions had the best survival with increasing force to failure.
  
  
  CONCLUSIONS
  Although a relationship was demonstrated between force to failure and base surface area, it was not a simple one. No statistically significant relationship was found between bond strength and base surface area.
authors: UCL Eastman Dental Institute, London, UK.
authors: Marvi
authors: M
authors: Talpur
authors: Susan J
authors: SJ
authors: Cunningham
authors: David R
authors: DR
authors: Moles
authors: Steven P
authors: SP
authors: Jones
mesh_terms: D001840:Dental Bonding; D003799:Dental Stress Analysis; D008422:Materials Testing; D016382:Orthodontic Appliance Design; D009967:Orthodontic Appliances; D011108:Polymers; D012044:Regression Analysis; D033081:Shear Strength; D013499:Surface Properties; D016019:Survival Analysis
chemical_list: D011108:Polymers