The Effect of the Length and Distribution of Implants for Fixed Prosthetic Reconstructions in the Atrophic Posterior Maxilla: A Finite Element Analysis

Abstract

In this study, different prosthetic designs that could be applied instead of advanced surgical techniques in atrophic maxilla were evaluated with finite element analysis. Atrophic posterior maxilla was modeled using computer tomography images and four models were prepared as follows: Model 1 (M1), two implants supporting a three-unit distal cantilever prosthesis; Model 2 (M2), two implants supporting a three-unit conventional fixed partial denture; Model 3 (M3), three implants supporting three connected crowns; and Model 4 (M4), two implants supporting two connected crowns. Implants 4 mm in width and 8 mm or 13 mm in length were used. A linear three-dimensional finite element programme was used for analysis. The maximum principle stress (tensile) and minimum principle stress (compressive) were used to display stress in cortical and cancellous bones. The von Mises criteria were used to evaluate the stress on the implants. M1 was found to be the most risky model. The short dental arch case (M4) revealed the lowest stresses among the models but is not recommended when one more implant can be placed because of the bending forces that could occur at the mesial implant. In M2 and M3, the distal implants were placed bicortically between the crestal and sinus cortical plates, causing a fall of the stresses because of the bicortical stability of these implants.

Three-dimensional finite element analysis of buccally cantilevered implant-supported prostheses in a severely resorbed mandible

“…With respect to maximum von Mises stress values in bone, cantilevered prosthesis has been reported to exhibit higher peak stress in the bone when compared to noncantilevered prosthesis 3 34 and so do high crown-to-implant ratio prostheses when compared to lower crown-to-implant ratio prostheses. 35 36 In the present study, Model CP2 with the cantilevered prosthesis showed a lower peak stress in cortical bone compared to Model PD2, which had a shorter cantilever and a higher crown-to-implant ratio.…”

A Minimally Invasive Technique for Short Spiral Implant Insertion with Contextual Crestal Sinus Lifting in the Atrophic Maxilla: A Preliminary Report

“…In the past, some concerns regarding complications due to the increased crown–implant ratio in prosthetic rehabilitation supported by short implants were reported. In this regard, the recent literature demonstrated that no correlation exists between occurrence of biological and technical complications and the crown–implant ratio of implant-supported reconstructions, in addition to the fact that the crown–implant ratio does not influence peri-implant crestal bone loss [ 19 , 20 , 21 , 22 ]. Besides, several studies reported on the efficacy of short implants compared to 10 mm or longer implants placed in crestally lifted sinuses, also showing no significant differences regarding prosthesis and implant failures, complications, and radiographic peri-implant marginal bone lose [ 1 , 2 , 3 , 9 , 10 , 15 , 16 , 17 , 18 , 19 ].…”

Investigation of the tensile state of the mandible with implants

“…Для расчета механические характеристики дентальной системы принято следующее: а) титановые имплантат, абатмент и проволока (шина)модуль упругости E = 110 ГПа, коэффициент Пуассона μ = 0,36 [1, 2, 3]; б) кортикальная (челюстная) кость, E = 29,3 ГПа, μ = 0,42 [7][8][9]. в) литая пластинка из сплава Co-Cr, E = 209 ГПа [4,5], μ = 0,3.…”

“…Инженерный подход к созданию ортопедических конструкций предусматривает применение механики деформируемого твердого тела. В настоящее время существует большое количество работ об исследовании напряженного состояния в ортопедических конструкциях как аналитическими и численными методами, так и методом фотоупругости [4][5][6][7][8][9][10][11][12][13][14]. Однако при планировании несъемных шинированых имплантатов обоснование выбора их расположения в нижней челюсти не проводили.…”