title: Experimentally induced abutment strains in three types of single-molar implant restorations.
abstract: BACKGROUND
  The choice of single-molar implant design is difficult because of a lack of controlled, quantitative biomechanical analyses.
  
  
  OBJECTIVE
  This study determined the effect of 3 single-molar implant designs on implant strains under a variety of homologous loading conditions.
  
  
  METHODS
  On each implant abutment, 4 strain gauges were placed axially at 90 degrees to each other on the buccal, lingual, mesial, and distal surfaces. Effects of implant design, load location, direction, and magnitude were tested on axial and bending (buccolingual and mesiodistal) strains of 3 single-molar implant designs: (1) single, 3.75-mm (regular) diameter implant, (2) single, 5-mm (wide) diameter implant, and (3) two 3.75-mm diameter (double) implants connected through a single-molar crown. Results were analyzed with ANOVA.
  
  
  RESULTS
  Variations in loading conditions induced 3-dimensionally complex abutment strains on the tested implant designs. Peak absolute strains in mesiodistal direction were 6493 microepsilon for design 1 and 3958 microepsilon on design 2, and 3160 microepsilon in buccolingual direction on design 3. For all loading conditions, the single 3.75-mm diameter implant consistently experienced the largest strains compared with wide-diameter and double implant designs. Changes in centric contact location affected implant abutment strains differently among the 3 designs. Angulated force direction resulted in larger bending strains.
  
  
  CONCLUSIONS
  For single-molar implant designs, an increase in implant number and diameter may effectively reduce experimental implant abutment strains.
authors.affiliation: School of Dentistry, University of Minnesota, Minneapolis 55455, USA. seong001@tc.umn.edu
authors.forename: W J
authors.initials: WJ
authors.lastname: Seong
authors.forename: T W
authors.initials: TW
authors.lastname: Korioth
authors.forename: J S
authors.initials: JS
authors.lastname: Hodges
mesh_terms: D000704:Analysis of Variance; D001696:Biomechanical Phenomena; D001732:Bite Force; D000044:Dental Abutments; D003758:Dental Implantation, Endosseous; D019250:Dental Implants, Single-Tooth; D017267:Dental Prosthesis Design; D003799:Dental Stress Analysis; D006801:Humans; D008334:Mandible; D008963:Molar; D018583:Pliability; D016474:Weight-Bearing