Stress Distribution In Implants Research Articles

Static and dynamic stress analysis of different crown materials on a titanium base abutment in an implant-supported single crown: a 3D finite element analysis

BackgroundThis Finite Element Analysis was conducted to analyze the biomechanical behaviors of titanium base abutments and several crown materials with respect to fatigue lifetime and stress distribution in implants and prosthetic components.MethodsFive distinct designs of implant-supported single crowns were modeled, including a polyetheretherketone (PEEK), polymer-infiltrated ceramic network, monolithic lithium disilicate, and precrystallized and crystallized zirconia-reinforced lithium silicates supported by a titanium base abutment. For the static load, a 100 N oblique load was applied to the buccal incline of the palatal cusp of the maxillary right first premolar. The dynamic load was applied in the same way as in static loading with a frequency of 1 Hz. The principal stresses in the peripheral bone as well as the von Mises stresses and fatigue strength of the implants, abutments, prosthetic screws, and crowns were assessed.ResultsAll of the models had comparable von Mises stress values from the implants and abutments, as well as comparable maximum and minimum principal stress values from the cortical and trabecular bones. The PEEK crown showed the lowest stress (46.89 MPa) in the cervical region. The prosthetic screws and implants exhibited the highest von Mises stress among the models. The lithium disilicate crown model had approximately 9.5 times more cycles to fatique values for implants and 1.7 times more cycles to fatique values for abutments than for the lowest ones.ConclusionsWith the promise of at least ten years of clinical success and favorable stress distributions in implants and prosthetic components, clinicians can suggest using an implant-supported lithium disilicate crown with a titanium base abutment.

Biomechanical behavior of all-on-4 concept and alternative designs under different occlusal load configurations for completely edentulous mandible: a 3-D finite element analysis.

The aim of this study was to evaluate the effect of the All-on-4 design and 4 alternative implant-supported fixed prosthesis designs on stress distribution in implants, peri-implant bone, and prosthetic framework in the edentulous mandible under different loading conditions using three-dimensional finite element analysis (3D-FEA).Five different experimental finite element models (Model A (unsplinted 6), Model B (splinted 6), Model C (All-on-4), Model D (axial; 2 anterior, 2 posterior), and Model E (4 interforaminal)) were created. Three different loading conditions were applied (canine loading, unilateral I-loading, and unilateral II-loading). The highest minimum (Pmin) and the maximum (Pmax) principal stress values were acquired for cortical and trabecular bones; the highest von Mises (mvM) stress values were obtained for implants and metal frameworks. Model B and Model D showed the most favorable stress distribution. The All-on-4 design (Model C) also showed acceptable stress values close to those of Model B and Model D in the cortical and trabecular bones. In accordance with the stress values in the bone structure, the lowest stress values were measured in the implants and Co-Cr framework in Model B and Model D. The highest stress values in all structures were measured for unilateral loading- II, while the lowest values were found for canine loading. It was concluded that Model B and Model D experimental models showed better biomechanical performance in all structures. Furthermore, the use of a splinted framework, avoiding cantilevers, results in lower stress transmission. On the other hand, canine loading and unilateral loading-I exhibited the best loading conditions.

Influence of diameter in the stress distribution of extra-short dental implants under axial and oblique load

Aim: This study evaluated the influence of a wide diameter on extra-short dental implant stress distribution as a retainer for single implant-supported crowns in the atrophic mandible posterior region under axial and oblique load. Methods: Four 3D digital casts of an atrophic mandible, with a single implant-retained crown with a 3:1 crown-to-implant ratio, were created for finite element analysis. The implant diameter used was either 4 mm (regular) or 6 mm (wide), both with 5 mm length. A 200 N axial or 30º oblique load was applied to the mandibular right first molar occlusal surface. The equivalent von Mises stress was recorded for the abutment and implant, minimum principal stress, and maximum shear stress for cortical and cancellous bone. Results: Oblique load increased the stress in all components when compared to axial load. Wide diameter implants showed a decrease of von Mises stress around 40% in both load directions at the implant, and an increase of at least 3.6% at the abutment. Wide diameter implants exhibited better results for cancellous bone in both angulations. However, in the cortical bone, the minimum principal stress was at least 66% greater for wide than regular diameter implants, and the maximum shear stress was more than 100% greater. Conclusion: Extra-short dental implants with wide diameter result in better biomechanical behavior for the implant, but the implications of a potential risk of overloading the cortical bone and bone loss over time, mainly under oblique load, should be investigated.

Retention and Stress Distribution of Implant Retained mandibular Complete Overdenture with Locator versus Ball and socket Attachments (An in vitro Study)

Retention and Stress Distribution of Implant Retained mandibular Complete Overdenture with Locator versus Ball and socket Attachments (An in vitro Study)

Stress Distribution with Different Angulation of Implant with or without Cantilever Extension: A Systematic Review

Introduction: To systematically review the literature on stress distribution of implants with different angulation and the effect of cantilever prosthesis. Study Design: The three major electronic databases were screened: MEDLINE (via PubMed), and Scopus and Elsevier. Review: Methodological quality assessment showed sample size calculation to be reported by only one study, and follow-up did not include a large number of participants - a fact that may introduce bias and lead to misleading interpretations of the study results. Conclusions: A systematic review of the current literature showed only in vitro evidence that there is no consensus on the advantage of using an offset configuration implant compared to those in straight-line configuration, well some studies shows significant improvement of bone stress distribution when an angulated implant is under oblique loading.

Comparative evaluation of short or standard implants with different prosthetic designs in the posterior mandibular region: a three-dimensional finite element analysis study

The purpose of this study is to evaluate the stress distribution of splinted or nonsplinted restorations supported by 2 short or 2 standard dental implants in the mandibular molar region using three-dimensional finite element analysis. Two standard implants (4.8 × 10mm) were placed in the mandibular molar area. Two short implants (4.8 × 6 mm) were located in the mandibular molar atrophied area. Implant-supported prostheses were simulated with splinted or nonsplinted crowns design. Vertical load of 200 N and oblique load of 100 N were applied on the central fossa and the buccal cusps. Evaluation of stress distribution in implants and peri-implant cortical bone using the finite element analysis software (Ansys, Version 2020, R2), a multipurpose computer design program. The maximum principal stress of cortical bone around the implants was higher in nonsplinted crowns when compared to splinted crowns. The stress concentration of cortical bone surrounding implants increased as the implant length decreased either splinted crowns or nonsplinted crowns. The short implants with nonsplinted crowns showed lower stresses when compared to standard implants with nonsplinted crowns. The results suggest that the nonsplinted prostheses supported by short dental implants might be considered in the molar area of the atrophic mandible.

Effects of Marginal Bone Loss Progression on Stress Distribution in Different Implant–Abutment Connections and Abutment Materials: A 3D Finite Element Analysis Study

Peri-implantitis is a common implant-supported prosthesis complication, and marginal bone loss affects the stress distribution in implant systems. This three-dimensional finite element analysis study investigated how bone loss affects the implant assembly; in particular, models including two implant systems with different connection systems (external or internal hexagon), abutment materials (titanium or zirconia), and bone loss levels (0, 1.5, 3, or 5 mm) were created. We observed that the maximum von Mises stress distinctly increased in the groups with bone loss over 1.5 mm compared to the group without bone loss, regardless of the connection system or abutment material used. Moreover, the screw stress patterns with bone loss progression were determined more by the connection systems than by the abutment materials, and the magnitude of the stress on the fixture was affected by the connection systems with a similar pattern. The highest stress on the screw with the external hexagon connection system increased over 25% when bone loss increased from 3 to 5 mm, exceeding the yield strength of the titanium alloy (Ti–6Al–4V) when 5 mm bone loss exists; clinically, this situation may result in screw loosening or fracture. The highest stress on the fixture, exceeding the yield strength of pure titanium, was noted with the internal hexagon connection system and 1.5 mm bone loss. Titanium and zirconia abutments—both of which are clinically durable—presented similar screw and fixture stress patterns. Therefore, clinicians should pay more attention to maintaining the peri-implant bone to achieve the long-term stability of the implant-supported prosthesis.

Stress Distribution Along the Implant-Bone Interface: A Pilot Study using Finite Element Analysis to Compare Tilted and Non-Tilted Implants under Different Loads

Introduction: This study used finite element analysis to evaluate stress distribution of implants placed at different angulations under two loadings. Stress was measured at the implant-bone interface. Methods: Four models of implant and bone were manufactured via three-dimensional optical scanning and point cloud data extraction. They included implants placed: 1) Without tilt 2) tilted at 15o, 3) tilted at 30o, and 4) tilted at 45o. A tissue-level implant was scanned, and a mandible bone model was extracted from cone-beam computed tomography systems. A 3D model of the implants in the mandible were constructed. The finite element analyses were carried out using simulation software. The physical interaction at implant-bone interfaces during loading were considered through bonded surface-to-surface contacts. Static loading (with axial forces of 150N and 300N) were applied to evaluate the implant-bone model. Results: The amount of stress along the implant-bone interface was greater under 300N loading than 150N loading. The stress along tilted implants were greater than that of non-tilted implants under both 150N and 300N. There was no significant variance among the various angles of implants. The displacements along the tilted implants were larger than those of nontilted implants. The stress distribution along the implant-bone interface increased when the loading increased. Conclusion: The tilted implants presented greater stress distribution. The in vitro stress distribution analysis using FEA will provide clinical guidance for implant placement.

Influence of Abutment Design on Stress Distribution in Narrow Implants with Marginal Bone Loss: A Finite Element Analysis.

The aim of this study was to determine the effect of solid (one-piece) and two-piece abutments on the stress profile of narrow implants with marginal bone loss. Solid and two-piece abutments were connected to a conical internal octagon-connection implant (3.3 mm in diameter, 10 mm in length) and restored with a single crown. Three-dimensional finite element analysis was used to simulate the stress distribution in implant models with different levels of marginal bone resorption (0, 1, 2, and 3 mm). The effect of the design variables under increased bone resorption scenarios, including abutment screw length and diameter, was assessed. Static loading was applied to determine the mechanical response of the implant and cortical and trabecular bone. Marginal bone resorption levels dominated the mechanical response under static loading conditions. A marginal bone loss of 3 mm significantly increased stress values in the implant vicinity and abutment screw. Both abutment designs displayed similar stress distribution in the surrounding bone, but lower stress values were observed in the implant body with two-piece abutments. The abutment screw length was more effective in the resultant stress, as the longer screws reduced the stress in the implants. Marginal bone resorption magnitude is the crucial parameter in biomechanics to determine the mechanical behavior. As bone loss increases, resultant stress around implants under mastication forces may lead to implant failure, regardless of abutment type.

Effect of bone quality and bone loss level around internal and external connection implants: A finite element analysis study

Statement of problemA consensus regarding the biomechanical effects of vertical bone loss in normal and osteoporotic bone tissue according to different implant-abutment interfaces is lacking. PurposeThe purpose of this finite element analysis study was to evaluate the effect of vertical bone loss (without bone loss; with 1.5-mm bone loss; with 3-mm bone loss; and with 4.5-mm bone loss) in normal and osteoporotic bone that received a Ø4×10-mm implant with different implant-abutment connections (external connection [external hexagon] and internal connection [Morse taper]) by using 3D finite element analysis. Material and methodsSixteen 3D models were simulated. Axial and oblique forces of 200 N and 100 N, respectively, were applied on the occlusal surfaces of the prostheses. Maximum principal stress and microstrain were determined from the bone tissue of each model. von Mises stress analysis was used to evaluate the stress distribution in implants and prosthetic components (fixation screws, abutment, and crown). ResultsThe results showed higher stress concentrations in models with bone loss as increased vertical bone loss contributed to higher stress and microstrain in the bone tissue, regardless of the quality of bone and implant-abutment connection. Osteoporotic bone contributed to increase in microstrain in the trabecular bone. The internal connection showed lower stress than the external connection implants only in models without marginal bone loss. Furthermore, higher stress concentrations were observed in the implants and fixation screws in models with increased bone loss and external connection implants, mainly under oblique loading. Osteoporotic bone did not affect stress distribution in the implants and prosthetic components. ConclusionsProgressive bone loss contributed to higher stress in the bone tissue, implants, and prosthetic components. The osteoporotic bone affects only the microstrain in the trabecular bone, but not the stress in the implants and prosthetic components. The internal connection implants showed lower stress in the cortical bone only in models without bone loss, while external connection implants exhibited higher stress in the implants and screws under oblique loading.

Three-dimensional finite element analysis of the influence of an abutment buffer layer on implant stress distribution

To study the stress distribution under dynamic loading in the presence or absence of an abutment buffer layer by using three-dimensional finite element analysis. A three-dimensional solid geometric model of an implant in a human mandible was established on the basis of CT scan data. A buffer-free abutment prosthesis and a buffer-abutment abutment prosthesis were installed above the implant. The buffer layer was made of high-density polyethylene. A vertical load of 200 N and a horizontal load of 100 N (45°) were concentrated on the centers of the implant restorations of the two groups. Stresses on the implant neck and body, abutment neck and body, central bolt neck and body, and bone interface were compared via three-dimensional finite element analysis. Stresses on the implant neck and body, abutment neck and body, central bolt neck and body, and bone interface on the abutment with a buffer layer were significantly lower than those on the abutment without a buffer layer. The increase in the buffer layer of the abutment neck significantly reduced stress on the implant neck, abutment, central bolt neck, and bone interface.

Yeni Vida Tutuculu Abutment Sistemlerine Simante Edilen İmplant Destekli Zirkonya Restorasyonların Biyomekanik Davranışları: Üç Boyutlu Sonlu Elemanlar Analiz Çalışması

Objective: The purpose of this study was to evaluate the biomechanical behaviors of non-engaging titanium base abutments (NTiBA) bonded to three-unit zirconia restorations in terms of stress distribution in implants and prosthetic components. Material and Methods: Three-dimensional (3D) models of a tissue-level and bonelevel implant systems and their screw-retained abutments (SRA) and NTiBA were created. A bone block representing the maxillary right posterior region was created, and the implants were placed in the first premolar and first molar areas. Six different three-unit implant-supported fixed dental prostheses (I-FDPs) models were created: tissuelevel implant, N-TiBA, 6 mm crown height (TL6); tissue-level implant, N-TiBA, 10 mm crown height (TL10); bone-level implant, SRA, 6 mm crown height (SR6); bone-level implant, SRA, 10 mm crown height (SR10); bone-level implant, N-TiBA, 6 mm crown height (BL6); bonelevel implant, N-TiBA, 10 mm crown height (BL10). The restoration material was determined as monolithic zirconia. In each model, equal vertical (200 N) and oblique (100 N) loads were applied to each tooth simultaneously. The stress distribution in the restoration, implant, abutments, and basal screws was evaluated through the von Mises stres analysis. Results: The TL6 and TL10 exhibited higher von Mises stres values in the implants and lower von Mises stress values in the abutments than in the other FEA models. The increase in the crown height resulted in higher stress values under oblique loading compared to vertical loading. Conclusion: The non-engaging connection type and crown height affected the stress distribution in the implant and prosthetic components.

Evaluation of Stress Distribution in Implants Used to Retain Auricular Prosthesis with V-shaped and Reverse Buttress Thread Design by Three-dimensional Finite Element Analysis

Evaluation of Stress Distribution in Implants Used to Retain Auricular Prosthesis with V-shaped and Reverse Buttress Thread Design by Three-dimensional Finite Element Analysis

Analysis of stress distribution in ceramic and titanium implants in alveolar sockets of the anterior region of the maxilla.

BackgroundIn the routine of dentistry, knowing the biomechanical properties of implant systems and their inherent stress distribution under force loading is an essential step to predict structural damage and biological responses. This study aimed to investigate stress distribution in zirconia and titanium implants and their biomechanical response in alveolar sockets of the anterior region of the maxilla through tridimensional finite element analysis.Material and MethodsFrom computed tomography scans of a reference patient, three models of the maxillary dental arch were designed with Rhinoceros 5.0 software (McNeel Europe™, Barcelona, Spain). In each model, a dental implant replaced the maxillary left central incisor. The implants consisted of M1) Zirconia Pure Ceramic Implant Monotype; M2) Zirconia Pure Ceramic ZLA; and M3) Titanium Bone Level - Roxolid SLA. Ceramic crowns were installed in all the implants. Implants and prostheses were loaded with 50N oblique and axial forces. Von-Mises and Mohr Coulomb criteria were used to assess stress distribution in the implant systems and perimplantar bone, respectively.ResultsTraction was detected in the cervical region of the palatal bone surface of all the models. Oppositely, compression was found in the cervical region of the vestibular bone surfaces.ConclusionsZirconia Pure Ceramic Implant Monotype had the best response under oblique force loading. Ceramic implants may be an alternative to replace titanium implants in fresh alveolar sockets in the anterior region of the maxilla. Key words:Finite elements, implants, stress, ceramic, titanium.

Comparative Study on Material Combinations of Various Dental Implant-abutment Systems

Objective: The aim of the study was to evaluate the effect of material combinations on stress distribution at implant-bone interface, which benefits the selection of implant-abutment system materials; Methods: The simplified models of mandibular bone, implant and mandibular molar were established by Geomagic studio and Solidworks. To assess the stress distribution of implants and the peri-implant bone tissue under different implant-abutment system material combinations. All were subjected to static loading and analyzed by finite element method. Results: The results showed that the stress distribution of each group was similar. The stress of the implant was concentrated at the upper thread, and the maximum stress appeared at the neck of the implant. The stresses in abutment were highest at the contact region around the implant. The maximum stress of the screw appeared in the first thread. The stresses in cortical bone and trabecular bone were highest at the crestal region around the implant. Conclusions: The use of implant-abutment system components with different material is possible, and optimal implant-abutment system material design need to consider the compatibility with abutment and implant material, so that we can acquire better comprehensive performance.

Effect of implant number and height on the biomechanics of full arch prosthesis

Aim: Aim: The goal of this study was to clarify the stress distribution in a full arch prosthesis according to the implant number and height in order to guide the clinical choice during planning. Methods: A computational analysis was performed to analyze the stress distribution in implants and bone tissue according to implant number (3, 4 or 5) and height (5, 8, 11 mm). A model of a jaw with polyurethane properties to simulate bone tissue was created through the Rhinoceros software (version 5.0 SR8, McNeel North America, Seattle, WA, USA). The titanium bar was fixed to the implant through a retention screw. The final geometry was exported in STEP format to ANSYS (ANSYS 15.0, ANSYS Inc., Houston, USA) and all materials were considered homogeneous, isotropic and linearly elastic. To assess distribution of stress forces, an axial load (200 N) was applied on the cantilever. Results in Von-Mises stress and strain criteria’s were obtained for implants and bone, respectively. Qualitative and quantitative evaluations were performed. Results: The implant number and height influenced the prosthesis biomechanics, with more von-Mises stress and bone strain concentration for combination of 3 implants with 5 mm. Conclusion: It was concluded that higer length and more quantity of implant supporting a full arch prosthesis promoted less stress concentration during the simulated load. Decreasing the number of implants in rehabilitation is more harmful than decreasing their length for the stress and strain distribution.

Influence of different implant-abutment connections on stress distribution in single tilted implants and peripheral bone: A three-dimensional finite element analysis.

The load transfer between the implant-bone interface depends on various factors, including loading type; material properties of the implant and prosthesis; and implant geometry, length, diameter, and shape. The purpose of this study was to evaluate stress distribution in single tilted bone-level implants with different connections and peripheral bone under vertical and oblique loads using three-dimensional (3D) finite element analysis (FEA).METHOS.3D models of four different implant systems and their abutments were created from the data (computer-aided design) of original implants and abutments scanned with an optical scanner. The implants were placed in the bone block at degrees of 0°, 15°, and 30°. Then, a 3D model of the metal-ceramic crown was created and a 100-N total load was applied vertically and obliquely. Stress analyses showed variable results depending on the connection design and tilting angle; however, the tube in tube (TIT) connection type exhibited lower stress values in most loading and tilting simulations. Increase in tilting angle showed variable results in each connection design. The TIT connection design was found to be more successful in terms of stress distributions in the implant components and the peripheral bone.

The Effect of Different Bar Materials on Stress Distribution in Implant Supported Mandibular Overdenture Supporting Structure. (An in-Vitro Study)

Objective: To study the effect of different bar materials (cobalt chromium & polyetheretherketone)on stress distribution in implant supported mandibular overdenture supporting structure .By using strain gauge analysis. Material and methods: Six bar attachments were made from different materials (cobalt chromium& polyetheretherketone)and were constructed in acrylic model for implant supported mandibular overdenture and determine stress distribution in implant and supporting structure by using strain gauge analysis. Results: Showing No statistically significant differencewas found between (CoCr) bars and (PEEK) bars on stress distribution in implantsupported mandibular overdenture supporting structure when Comparison betweenrecorded microstrains measured with unilateral and bilateral load application.Conclusion: The cobalt chromium bars are subjected to more stresses than polyetheretherketone.Significantly greater amount of stresses are transmitted to the implantswhether unilateral or bilateral in all loading situations. Unilateral loading is more traumatic to the implants and residual ridge compared to bilateral loading.

STUDYING THE EFFECT OF THE PRELOAD INDUCED BY SCREW TIGHTENING ON STRESS DISTRIBUTION OF A DENTAL IMPLANT

The success of implants is largely dependent on initial stability and long-term osseointegration due to optimal stress distribution around the bone and implant. The purpose of this study is the numerical analysis of stress distribution in jaw bone and implant using finite element analysis considering the static forces caused by screw tightening and masticatory preloads. These forces and design limitations have been applied in accordance with implant science in dentistry to provide a proper stress distribution. First, all the parts were modelled with Solidworks software and then transferred to Abaqus software for analysis and applying the forces. For a better and more exact stress distribution analysis in the bone and implant, this analysis was conducted by two steps, that after determining the properties of each part, boundary conditions, loading and finally meshing the complex using hexahedral meshes and Match mesh technique, the abutment was tightened inside the implant with different tightening torques through six tests to apply preload in first step which this force applying induced stress in jaw and implant. Then, the amount of jaw force was applied to the crown surface. The results showed that the preload is quite effective in bone and implant stress distribution. However, its value only affects the surface stresses of the implant and has little effect on the of jaw bone stress value. This study can be carried on to evaluate the implants life considering Preload.

EFFECT OF TWO DIFFERENT RESTORATIVE MATERIALS ON STRESS DISTRIBUTION ON ALL-ON-FOUR IMPLANT RETAINED RESTORATIONS

Purpose: The purpose of this in vitro study was to evaluate the effect of restorative material either zirconia or BioHPP on stress distribution affecting periimplant supporting structures.Materials and methods: Four implants were installed using a surveyor in a maxillary model. Scan bodies were used to scan implant fixture position using identica hybrid desktop scanner then Exocad software was used to design a cutback implant retained restoration. VHF 5 axis milling machine was used for manufacturing of zirconia & bioHPP restoration from the same STL design, veneering was then performed by feldspathic porcelain & composite respectively. Strain gauge was installed 1mm distal to implant fixture. Universal testing machine was used to apply both axial & off axial loads 100 N & microstrains were recorded to test amount of developed strain around implant. Results: The results of independent t test showed that there was no statistically significant effect between bioHPP and Zirconia groups under axial loading (p= 0.064) and off axial loading (p=0.11) Conclusions: Based on the present in vitro results, the change in restoration material did not affect the stress distribution in implants and peripheral bone under axial & off axial loads.