Finite element analysis of three designs of an implant-supported molar crown
ABSTRACT Statement of problemThe optimal method of implant support for a single mandibular molar crown is controversial because commonly used, threaded, root-form implants developed by Branemark were not originally designed to support individual crowns.PurposeThe purpose of this study was to develop a finite element model of a single mandibular first molar crown supported by (1) a standard 3.75-mm–diameter implant, (2) a 5-mm, wide-diameter implant, and (3) double standard-diameter implants, and to compare the induced displacements as a result of various loading conditions.Material and methodsThree-dimensional finite element models were made to simulate the 3 single-molar implant designs. Each model was analyzed with 2 force magnitudes (35 N and 70 N) and with 2 force directions (vertical and 15 degrees to the vertical axis). Displacements in 3-dimensional space as a result of the simulated loading conditions were evaluated along 3 primary axes, mesiodistal, faciolingual, and superior-inferior.ResultsMesiodistal and buccolingual displacements for the crown supported by the 5-mm–diameter implant were reduced by approximately 50% compared with the crown supported by the 3.75-mm implant when the crowns were loaded at the distobuccal cusp tip or the distal marginal ridge. The double-implant design recorded the least mesiodistal displacement with off-center loading of the crown.ConclusionWhen the crown was loaded off-center, the double-implant design produced substantially less displacement when compared with either of the single-implant designs.
Article: Stress distribution of an internal connection implant prostheses set: a 3D finite element analysis.[show abstract] [hide abstract]
ABSTRACT: This study evaluated the stress distribution by loads, under a internal connection implant system with two sort of abutment screws and prosthetic crown models at ten observation points. The analysis were made in two models with internal butt joint, and with gold and titanium screw, respectively. The load was 382N with 90 masculine to the occlusal surface and 15 masculine to the implant axis at 4 and 6 mm from the implant center. In both models, a large amount of stress was located around the implant neck and little stress was concentrated along the abutment screw. The simulations made suggest that the internal connection protects the abutment screw from the accumulated stresses; however, it exposes the implant walls to these stresses.Stomatologija / issued by public institution "Odontologijos studija" ... [et al.] 01/2009; 11(2):55-9.
Article: Bendable vs. angulated dental implants: consideration of elastic and plastic material properties based on experimental implant material data and FEA.[show abstract] [hide abstract]
ABSTRACT: Bendable and angulated single-piece implants are used alternatively to screwable abutments in two-piece dental implant designs. Though used frequently, data on the stress distribution within such implants are not available and the question whether the bending contributes to fracture resistance has not been addressed. We used the method of finite element to identify von Mises stresses and maximum stresses in bent and non-bent but angulated implants. Implants with one (e.g. applicable to screw designs) or two (applicable to basal implants) bending areas were the variables under investigation. For bends up to 13 degrees we discovered that if there is only one bend, the maximum stress is in the bent area. If two bends are made in two different bending areas, the maximum stresses are distributed between the two and, if either one of the bent areas is machined, there are no residual stresses within the implant body in this area. The maximum stresses are always located near the base-plates. The absolute value of the maximum stress is higher because no residual stresses are available to compensate stresses that stem from loading. Assuming that all other parameters are equal, bendable (basal) implants show a more even stress distribution along the vertical implant region than identically shaped implants with a machine-angulated area. Bendable basal implants therefore probably resist masticatory forces better than pre-angulated, machined implants, and unbent implants which provide a thin region in the vertical implant area.Biomedical papers of the Medical Faculty of the University Palacky, Olomouc, Czechoslovakia 01/2009; 152(2):309-16.
Article: Evaluation of Micromovements and Stresses around Single Wide-Diameter and Double Implants for Replacing Mandibular Molar: A Three-Dimensional FEA.[show abstract] [hide abstract]
ABSTRACT: Purpose. The purpose of this finite element study was to compare stresses, strains, and displacements of double versus single implant, in immediate loading for replacing mandibular molar. Materials and Methods. Two 3D FEM models were made to simulate implant designs. The first model used 6 mm wide-diameter implant to support a single molar crown. The second model used 3.75-3.75 double implant design. Each model was analyzed with a single force magnitude of 70 N in oblique axis in three locations. Results. This FEM study suggested that micromotion can be well controlled by both double implants and 6 mm single wide-diameter implant. The Von Mises stress for double implant had 31%-43% stress reduction compared to the 6 mm implant. Conclusion. Within the limitations of the paper, when the mesiodistal space for artificial tooth is more than 12.5 mm, under immediate loading, the double implant support should be considered.ISRN dentistry. 01/2012; 2012:680587.