The staggered installation of dental implants and its effect on bone stresses.
OBJECTIVE
The aim of this study was to investigate the effect of offsetting the middle or peripheral implant on the compressive stress values in the crestal bone around the neck of the dental implant.


METHODS
Three finite element models describing three titanium implants installed in quadrilateral pieces of bone was executed. A 2-mm nickel chromium superstructure representing a bridge was modeled over the implant abutments. In model 1, implants were installed along a straight line. Model 2 had the middle implant installed outside the line connecting the two peripheral implants buccally. Model 3 had the mesial implant installed out of alignment. Six 100-N loads were modeled on top of the mesial and middle implants of the three models individually. Loads 1 and 2 were directed vertically on the mesial and middle implants, while loads 3 and 4 represented the horizontal loads in the buccal direction. Loads 5 and 6 were directed mesially on the mesial and central implants. Maximal compressive stress levels in the crestal bone of the three models were then investigated.


RESULTS
The results demonstrated that offset implant installation revealed slightly lower bone stresses under buccally or lingually directed horizontal forces. Slightly higher bone stresses under vertical loads were observed. Horizontal mesial or distal loads resulted in slightly higher bone stresses than those caused by buccal or lingual loading.


CONCLUSIONS
The in-line implant alignment clearly had the safest compressive stress outcome on the surrounding structure under vertical loads. Under buccolingual loads, implant alignment with peripheral offset would have, relatively, the safest compressive stress outcome on bone.
Abu-Hammad
Osama
O
Department of Conservative Dentistry and Prosthodontics, Faculty of Dentistry, University of Jordan, Amman, Jordan.
Khraisat
Ameen
A
Dar-Odeh
Najla
N
Jagger
Daryll C
DC
Hammerle
Christoph H F
CH
D001696:Biomechanical Phenomena; D002858:Chromium Alloys / Q000737:chemistry; D003198:Computer Simulation; D000044:Dental Abutments; D003758:Dental Implantation, Endosseous / Q000379:methods*; D015921:Dental Implants; D003764:Dental Materials / Q000737:chemistry; D019094:Dental Prosthesis, Implant-Supported; D020342:Finite Element Analysis; D006801:Humans; D008334:Mandible / Q000502:physiology*; D008954:Models, Biological; D016348:Osseointegration / Q000502:physiology; D013314:Stress, Mechanical; D013499:Surface Properties; D014025:Titanium / Q000737:chemistry; D016474:Weight-Bearing
D002858:Chromium Alloys; D015921:Dental Implants; D003764:Dental Materials; D014025:Titanium