Treatment planning of implants when 3 mandibular posterior teeth are missing:  a 3-dimensional finite element analysis.
OBJECTIVE
To analyze the biomechanics of 3 designs of implant treatment for 3 teeth missing in posterior low arch quadrants.


METHODS
A posterior portion of the human mandible missing 44, 45, 46 and three 4.1 × 10 mm threaded ITI implants with crowns were used to construct the finite element model. According to 3 implants being single, splinted or 2 implants support fixed partial denture (FPD) fixed in bone segments. Three implant support conditions were prepared with ANSYS 10.0. A load of 100 N was applied at the central fossa of the occlusal surfaces of the crowns at 45 degrees buccolingually along the triangular ridge of the buccal cusp. The von Mises stress and strain distributions in periimplant bone were observed.


RESULTS
The results demonstrated that the von Mises stress in the supporting bone of the 2-implant supported FPD significantly increased compared with that in the 3-implant replacement. Meanwhile, when 3 implants were splinted, only the median implant had a decreased and more homogenous stress distribution, and the other implants did not exhibit significant differences when splinted.


CONCLUSIONS
This study suggests that when space and cost permit, a 2-implant supported FPD should not be used, and 1 implant for each missing tooth being single is recommended.
Department of Prosthodontics, The Third Affiliated Hospital, Sun Yat-sen University, Guangzhou, China.
Xia-Yun
XY
Chen
Chun-Yuan
CY
Zhang
Er-Ming
EM
Nie
Mei-chao
MC
Zhang
D000538:Aluminum Silicates / Q000737:chemistry; D001696:Biomechanical Phenomena; D001732:Bite Force; D003198:Computer Simulation; D003442:Crowns; D015921:Dental Implants; D003764:Dental Materials / Q000737:chemistry; D003776:Dental Porcelain / Q000737:chemistry; D017267:Dental Prosthesis Design; D019094:Dental Prosthesis, Implant-Supported; D003799:Dental Stress Analysis / Q000295:instrumentation; D003779:Denture Design; D003830:Denture, Partial, Fixed; D020342:Finite Element Analysis; D006801:Humans; D021621:Imaging, Three-Dimensional / Q000379:methods*; D007576:Jaw, Edentulous, Partially / Q000534:rehabilitation / Q000601:surgery*; D008334:Mandible / Q000601:surgery*; D008954:Models, Biological; D010347:Patient Care Planning; D017680:Potassium Compounds / Q000737:chemistry; D013314:Stress, Mechanical; D014025:Titanium / Q000737:chemistry
D000538:Aluminum Silicates; D015921:Dental Implants; D003764:Dental Materials; D017680:Potassium Compounds; D003776:Dental Porcelain; C016447:feldspar; D014025:Titanium