A Three-Dimensional Finite Element Study on the Biomechanical Simulation of Various Structured Dental Implants and Their Surrounding Bone Tissues

Pang

Computational and Mathematical Methods in Medicine

et al. 2019

Purpose. To evaluate the effects of different placements of mesial implants and different angles of distant implants in maxillary edentulous jaws on the stress on the implant and the surrounding bone tissue under dynamic loading. Materials and Methods. Cone beam computed tomography was used to acquire images of maxillary edentulous jaws. Using Mimics 17.0, Geomagic, and Unigraphics NX8.5 software, three-dimensional models were established: two mesial implants were placed vertically in the anterior region of the maxilla (bilateral central incisor, lateral incisor, and canine), and two distant implants were placed obliquely in the bilateral second premolar area at different inclined angles (15°, 30°, and 45°). The established models were designated I–IX. The models were subjected to dynamic load using Abaqus 6.12, with the working side posterior teeth loading of 150 N and simulation cycle of 0.875 s. Results. During the second to fourth phases of the mastication cycle, the stress was mainly concentrated on the neck of the distal implant. The stress of the distal implants was greater than that of mesial implants. Stress levels peaked in the third stage of the cycle. The stress of the distal cortical bone of distal implant of Model I reached the maximum of 183.437 MPa. The stress of the distal cortical bone and cancellous bone of distal implant of Model VIII represented the minima (62.989 MPa and 17.186 MPa, respectively). Conclusions. Our models showed optimal stress reductions when the mesial implants were located in the canine region and the distal implants tilted 30°.

Section: Introductionmentioning

confidence: 99%

Effects of Different Positions and Angles of Implants in Maxillary Edentulous Jaw on Surrounding Bone Stress under Dynamic Loading: A Three-Dimensional Finite Element Analysis

Pang

Computational and Mathematical Methods in Medicine

et al. 2019

The Journal of Contemporary Dental Practice

“…Bone simulation around the implant wasn't simulated in this study due to evidence that during the preload there's minimal transfer of stresses to it. 24,26 Beyond this limitations, the use of prosthetic crown and different abutments, the use of multiple implants, different size and width of the implants and the application of external load are factors that could alter the results found.…”

Section: Resultsmentioning

confidence: 99%

“…It allows greater control of variables related to the experiment without the risks and costs of implementation gathering elaborate data that cannot be obtained using conventional methods. 6,7,16,[24][25][26] Hence, this study aims to compare the stress distribution caused by different torque loads on prosthetic screws of external hexagon (EH) and morse taper (MT) implants. The specific objectives are: to compare quantitatively the stress distribution created by the preload simulation on the prosthetic screw of two different implant models with your respective pilars and to compare the maximum tensions generated with the recommended preload for the external hexagon and morse taper by the manufacturer and 10 Ncm above.…”

Section: Introductionmentioning

confidence: 99%

A Comparison of Torque Stress on Abutment Screw of External Hexagon and Morse Taper Implant

Linden¹,

Paranhos²,

Rodrigues³

et al. 2018

Aim: This three-dimensional (3D) finite element analysis observed the stress distribution on the prosthetic screws on external hexagon implant and morse taper implant with different tightening loads. Materials and methods:For this, two different 3D models assembly were obtained from the manufacturer and transferred to finite element analysis software: External hex implant model (EHM), and Morse taper implant model (MTM), both compounds by 3.75 x 7 mm implant, abutment and abutment screw. Bolt pretension force was applied on the shaft next to the threads of the prosthetic abutment. Preload was calculated using the torque on the prosthetic screw as recommended by the manufacturer (EHM30 and MTM20) and 10 Ncm torque above the manufacturer recommendations (EHM40 and MTM30). Maximum von mises equivalent stresses were obtained on the screws. Results: Preload values results were 243.18N (EHM30), 229.71N (MTM20), 324.24N (EHM40) and 344.57N (MTM30). In EHM30, EHM40 and MTM20 models the maximum stresses were below the yield strength of the abutment screw material. However, the maximum stress in MTM30 model was higher than the reference value. Conclusion:The torque loads above the manufacturer recommendations can cause plastic deformation in the MT abutment screw threads. The screws of morse taper implant can be more sensitive to higher loads than external hexagon implant. Clinical significance:The adequate torque can result in screw loosening, while fracture may occur if torque is excessive. Abutment screw suffers many screwing cycles in its lifetime in a way that some tightening forces are above manufacturer recommen dations.

“…Despite the possibility of reducing the treatment longevity due to implant's inclination the clinician will need this arrangement several times due to anatomical accidents and bone disposition which restricts installation sites 7 . The decision to install an inclined implant can be scientifically based on several articles that evaluated inclined implants in anterior regions, with reduced occlusal load and contact on the prosthetic crown's palatine face [8][9][10] . These studies mostly express a common clinical situation and provide the dentist with an initial basis that inclined implants aggravate the strain generated around the supporting tissue, but the physiological limit is still maintained 9 .…”

Section: Introductionmentioning

confidence: 99%

Biomechanical effect of inclined implants in fixed prosthesis: strain and stress analysis

Rodrigues

Tribst

Santis

et al. 2018

Rev. odontol. UNESP

Introduction Implant inclinations can be corrected using mini abutments at different angulations. Objective To analyze the influence of external hexagon implants in different inclinations (3 levels) on the microstrain distribution generated around three implants. Method A geometric bone model was created through Rhinoceros CAD software (version 5.0 SR8, Mcneel North America, Seattle, WA, USA). Three implants (4.1 × 13 mm) were modeled and inserted inside the substrate at three different inclinations: 0º, 17º and 30º. Next, all groups received mini conical abutments, fixation screws and a simplified prosthesis. The final geometry was exported in STEP format to analysis software and all materials were considered homogeneous, isotropic and linearly elastic. An axial load (300N) was applied on the center of the prosthesis. An in vitro study was conducted with same conditions and groups for validating the tridimentional model. Result Stress was concentrated on the external area of the implants, in contact with the cortical bone and external hexagon. For the bone simulator, the strain increased in the peri-implant region according to the increase in the implant’s inclination. The difference between groups was significant (p = 0.000). The 30º group presented higher stress and strain concentration. Conclusion The microstrain and stress increase around implants directly proportional to the increase of the installation angle.