Influence of Implant Location, Number, and Design in Ischemic Zone for Implant Prosthesis Success Rate: A Comparative Three-Dimensional Finite Element Analysis.

BACKGROUND

The performance of an implant-supported prosthesis depends on the implant type, number, implant location, and prosthesis design which is directly associated with the distribution of the occlusal forces during mastication. The purpose of the present study is to analyze with three-dimensional (3D) finite element comparative analysis, the influence of implant location, number, and prosthesis design in the mandibular posterior region where multiple posterior teeth replacement is indicated, which in turn is associated with the longevity or Implant success rate.

MATERIAL AND METHODS

Mandibular posterior section, where 4 teeth are missing, based on the space available for implants and following the surgical guide instructions, a standard make four implants (1st and 2nd premolars {3.8 mm × 11.5 mm}, 1st and 2nd molar {5.1 mm × 11.5 mm}) were selected and with standardization for placement, 4 groups were created with different implant location, number and prosthesis design from the selected implants as model FM, FM, FM, FM. Finite element analysis was carried out using ANSYS software, version 14.5 (ANSYS Inc., Canonsburg, PA, USA) for assessment of stress, strain, and deformation around implant and bone.

RESULTS

Maximum von Mises stress on vertical loading was highest for FM (139.55MPa) model (center of prosthesis on premolar and molar pontics) and lowest for FM (53.65MPa) model (on 2nd premolar pontic) with values in decreasing order as FM ˃ FM ˃ FM ˃ FM. Maximum von Mises stress on oblique loading was highest at the distal of 1st molar implant pontic for FM (539.81MPa) and lowest at the 2nd premolar pontic for FM (352.48MPa) model with values as FM˃FM˃FM˃FM. Deformation for vertical and oblique loading was observed minimum at the buccal cusp and buccal crestal bone of 2nd premolar, 1st molar on FM model against highest deformation on buccal and lingual crestal bone, cuspal area of 2nd premolar, 1st molar implants. For oblique loading minimum deformation was seen for the 2nd premolar, 1st molar cuspal area in FMand maximum at the 2nd premolar region in FM.

CONCLUSION

Four single implants may be chosen if there is enough mesiodistal and buccolingual space to allow for a minimum inter-implant and inter-implant-tooth distance that can be maintained while putting the least amount of stress on the implants and bone. To reduce stress on the bone and implants, it is best to avoid long-span implant-supported prostheses when using fixed implant-supported prostheses.