title: [Effect of the number and inclination of implant on stress distribution for mandibular full-arch fixed prosthesis].
abstract: OBJECTIVE
  To study the effect of implant number and inclination on stress distribution in implant and its surrounding bone with three-dimensional finite element analysis.
  
  
  METHODS
  A special denture was made for an edentulous mandible cast to collect three-dimensional finite element data. Three three-dimensional finite element models were established as follows. Model 1: 6 paralleled implants; model 2: 4 paralleled implants; model 3: 4 implants, the two anterior implants were parallel, the two distal implants were tilted 30° distally.
  
  
  RESULTS
  Among the three models, the maximum stress values found in anterior implants, posterior implants, and peri-implant bone were modle 3<modle 1<modle 2 in turn. The effect of implant numbers on stress distribution was as follow: the maximum stress value of the anterior and posterior implant, and the peri-implant bone of model 2 were 126.8, 267.4, and 40.0 MPa, which was 35.8%, 3.8% and 7.8% higher than those in model 1 (93.4, 257.7, 37.1 MPa) respectively. The impact of implant inclination on stress distribution was as follow: when the distal implant titled 30° in model 3, the maximum stress value of the anterior and posterior implant, and the peri-implant bone were 82.0, 239.5 and 28.7 MPa, which was 35.4%, 10.5% and 28.2% lower than those in model 2 respectively.
  
  
  CONCLUSIONS
  Within the limitation of this study, when implants are placed parallel, the maximum stress of the distal implant can be reduced by increasing the number of implant.When the number of implant was decreased from six to four, the maximum stress around the implant can be reduced by tilting the distal implant. This design will provide a better prostheses effect than the design with six implants does.
authors.affiliation: Department of Stomatology, Changhai Hospital, The Second Military Medical University, Shanghai 200433, China.
authors.forename: Xiaoying
authors.initials: X
authors.lastname: Zheng
authors.forename: Xiaomei
authors.initials: X
authors.lastname: Li
authors.forename: Zhen
authors.initials: Z
authors.lastname: Tang
authors.forename: Lulu
authors.initials: L
authors.lastname: Gong
authors.affiliation: Email: wang_dento@163.com.
authors.forename: Dalin
authors.initials: D
authors.lastname: Wang
mesh_terms: D015921:Dental Implants; D017267:Dental Prosthesis Design; D019094:Dental Prosthesis, Implant-Supported; D003799:Dental Stress Analysis; D020342:Finite Element Analysis; D008334:Mandible; D019736:Prostheses and Implants; D019919:Prosthesis Implantation
chemical_list: D015921:Dental Implants