scholarly journals Photoelastic analysis of stress distribution on parallel and angled implants after installation of fixed prostheses

2004 ◽  
Vol 18 (1) ◽  
pp. 45-52 ◽  
Author(s):  
Cristiane Ueda ◽  
Roberto Adrian Markarian ◽  
Cláudio Luiz Sendyk ◽  
Dalva Cruz Laganá
Keyword(s):  
Stress Distribution ◽  
Apical Region ◽  
Axial Loads ◽  
Bone Morphology ◽  
Prosthetic Rehabilitation ◽  
Implant Placement ◽  
Isochromatic Fringes ◽  
Fixed Prosthesis ◽  
Photoelastic Analysis ◽  
Surrounding Bone

The longevity of implant-supported prosthetic rehabilitation depends largely on how the masticatory forces are transferred to the implants and surrounding bone. Anatomical conditions, bone morphology and aesthetics usually dictate implant placement in less than ideal positions for prosthetic rehabilitation and sometimes it is possible to find them with different inclinations. The purpose of this paper was to compare, through photoelastic analysis, the stress distribution in a fixed prosthesis with 3 parallel implants, to the stress distribution in the same prosthesis in the existence of an angled central implant. Two photoelastic resin models were made and a polariscope was used in the visualization of isochromatic fringes formed in the models when axial loads of 2 kg, 5 kg and 10 kg were applied to a unique central point of the prosthesis. The presence of inducted tensions (preloads) was observed in the models after applying torque to the retention screws. Preloads were intensified with the incidence of occlusal forces. In the parallel implants, the force dissipation followed the long axis. The angled implant had a smaller quantity of fringes and the stresses were located mostly around the apical region of the lateral implants.

Photoelastic Analysis on Different Retention Methods of Implant-Supported Prosthesis

2015 ◽  
Vol 41 (3) ◽  
pp. 258-263 ◽  
Author(s):  
Angélica Castro Pimentel ◽  
Marcello Roberto Manzi ◽  
Cristiane Ibanhês Polo ◽  
Claudio Luiz Sendyk ◽  
Maria da Graça Naclério-Homem ◽  
...  
Keyword(s):  
Stress Distribution ◽  
Axial Load ◽  
Testing Machine ◽  
Compressive Load ◽  
Lower Intensity ◽  
Photoelasticity Method ◽  
Universal Testing ◽  
Isochromatic Fringes ◽  
Photoelastic Analysis ◽  
Compressive Axial Load

The aim of this study was to evaluate the stress distribution of different retention systems (screwed, cemented, and mixed) in 5-unit implant-supported fixed partial dentures through the photoelasticity method. Twenty standardized titanium suprastructures were manufactured, of which 5 were screw retained, 5 were cement retained, and 10 were mixed (with an alternating sequence of abutments), each supported by 5 external hexagon (4.0 mm × 11.5 mm) implants. A circular polariscope was used, and an axial compressive load of 100 N was applied on a universal testing machine. The results were photographed and qualitatively analyzed. We observed the formation of isochromatic fringes as a result of the stresses generated around the implant after installation of the different suprastructures and after the application of a compressive axial load of 100 N. We conclude that a lack of passive adaptation was observed in all suprastructures with the formation of low-magnitude stress in some implants. When cemented and mixed suprastructures were subjected to a compressive load, they displayed lower levels of stress distribution and lower intensity fringes compared to the screwed prosthesis.

Photoelastic Analysis of Stress Distribution With Different Implant Systems

2014 ◽  
Vol 40 (2) ◽  
pp. 117-122 ◽  
Author(s):  
Eduardo Piza Pellizzer ◽  
Rafael Imai Carli ◽  
Rosse Mary Falcón-Antenucci ◽  
Fellippo Ramos Verri ◽  
Marcelo Coelho Goiato ◽  
...  
Keyword(s):  
Stress Concentration ◽  
Stress Distribution ◽  
Testing Machine ◽  
Load Direction ◽  
Mass Model ◽  
Load Model ◽  
Universal Testing ◽  
Isochromatic Fringes ◽  
Photoelastic Analysis ◽  
Oblique Load

The aim of this study was to evaluate stress distribution with different implant systems through photoelasticity. Five models were fabricated with photoelastic resin PL-2. Each model was composed of a block of photoelastic resin (10 × 40 × 45 mm) with an implant and a healing abutment: model 1, internal hexagon implant (4.0 × 10 mm; Conect AR, Conexão, São Paulo, Brazil); model 2, Morse taper/internal octagon implant (4.1 × 10 mm; Standard, Straumann ITI, Andover, Mass); model 3, Morse taper implant (4.0 × 10 mm; AR Morse, Conexão); model 4, locking taper implant (4.0 × 11 mm; Bicon, Boston, Mass); model 5, external hexagon implant (4.0 × 10 mm; Master Screw, Conexão). Axial and oblique load (45°) of 150 N were applied by a universal testing machine (EMIC-DL 3000), and a circular polariscope was used to visualize the stress. The results were photographed and analyzed qualitatively using Adobe Photoshop software. For the axial load, the greatest stress concentration was exhibited in the cervical and apical thirds. However, the highest number of isochromatic fringes was observed in the implant apex and in the cervical adjacent to the load direction in all models for the oblique load. Model 2 (Morse taper, internal octagon, Straumann ITI) presented the lowest stress concentration, while model 5 (external hexagon, Master Screw, Conexão) exhibited the greatest stress. It was concluded that Morse taper implants presented a more favorable stress distribution among the test groups. The external hexagon implant showed the highest stress concentration. Oblique load generated the highest stress in all models analyzed.

scholarly journals Effect of mucosa thicknesses on stress distribution of implant-supported overdentures under unilateral loading: Photoelastic analysis

2019 ◽  
Vol 17 (4) ◽  
pp. 228080001988264
Author(s):  
Ozgun Yusuf Ozyilmaz ◽  
Filiz Aykent ◽  
Gulsum Sayin Ozel
Keyword(s):  
Stress Distribution ◽  
Surrounding Tissue ◽  
Vertical Force ◽  
Test Models ◽  
Isochromatic Fringes ◽  
Mucosal Thickness ◽  
Photoelastic Analysis ◽  
Photoelastic Stress ◽  
The Right ◽  
Mandibular Overdenture

Introduction: The aim of this study was to evaluate the effect of different heights of attachment and mucosa thicknesses on the stress distribution of two implant-retained mandibular overdenture designs under loading using the photoelastic stress analysis method. Materials and methods: Six photoelastic models of an edentulous mandibula were fabricated with two solitary implants that were placed in the canine regions. The attachment systems studied were ball and locator stud attachments. Both the ball and locator groups included three models that had different residual ridge heights so as to provide different mucosa thicknesses (1 mm–1 mm, 1 mm–2 mm, 1 mm–4 mm). A static vertical force of 135 N was applied unilaterally (each on the right then the left side) to the central fossa of the first molars. Models were positioned in the field of a circular polariscope to observe the distribution of isochromatic fringes around the implants and the interimplant areas under loading. The photoelastic stress fringes were monitored and recorded photographically. Results: The ball attachment groups showed higher stress values than did the locator groups under loading. Both attachment systems produced the lowest stress values in stimulated 1 mm–1 mm mucosa thickness models. The models with 1 mm–2 mm mucosa thicknesses showed higher stress values than did other models for both attachment systems. The highest stress value observed around both attachment systems was the moderate level in all test models. Conclusion: In different height mucosa thicknesses, locator attachment models distributed the load to the other side of the implant and its surrounding tissue, whereas the ball attachment did not. Regardless of mucosal thickness and attachment type, the implant on the loading side was subjected to the highest stress concentration.

Immediate Functional Loading of an Implant-Supported Fixed Prosthesis at the Time of Ablative Surgery and Mandibular Reconstruction for Squamous Cell Carcinoma

2010 ◽  
Vol 36 (3) ◽  
pp. 225-230 ◽  
Author(s):  
Guillaume Odin ◽  
Thierry Balaguer ◽  
Charles Savoldelli ◽  
Gérard Scortecci
Keyword(s):  
Squamous Cell Carcinoma ◽  
Cell Carcinoma ◽  
Squamous Cell ◽  
External Beam Radiotherapy ◽  
Mandibular Reconstruction ◽  
Implant Placement ◽  
Fibula Free Flap ◽  
Ablative Surgery ◽  
Fixed Prosthesis ◽  
Implant Loading

Abstract The authors describe a case of squamous cell carcinoma of the oral cavity managed by ablative surgery, mandibular reconstruction with a fibula free flap, and implant placement during the same session. Immediate functional implant loading, respecting the principles of basal implantology, was performed 48 hours later using a highly rigid, screw-secured fixed prosthesis that served as an external fixator for the implants and grafted bone. Implant loading before external beam radiotherapy improves flap stability, bone consolidation, and quality of life. Functional and esthetic outcomes were evaluated 2 years after radiotherapy was completed.

Stress in Bonded Adherends for Single Lap Joints

1996 ◽  
Vol 12 (03) ◽  
pp. 167-171
Author(s):  
G. Bezine ◽  
A. Roy ◽  
A. Vinet
Keyword(s):  
Finite Element ◽  
Shear Stress ◽  
Numerical Model ◽  
Stress Distribution ◽  
Normal Stress ◽  
Lap Joints ◽  
Axial Loads ◽  
Normal Stress Distribution ◽  
Single Lap Joints ◽  
Element Technique

A finite-element technique is used to predict the shear stress and normal stress distribution in adherends for polycarbonate/polycarbonate single lap joints subjected to axial loads. Numerical and photoelastic results are compared so that a validation of the numerical model is obtained. The influences on stresses of the overlap length and the shape of the adherends are studied.

PHOTOELASTIC ANALYSIS OF STRESS DISTRIBUTION ON THE TIBIOFEMORAL JOINT AFTER MENISCECTOMY

Orthopedics ◽  
1992 ◽  
Vol 15 (12) ◽  
pp. 1445-1450
Author(s):  
Joo-Chul Ihn ◽  
Myun-Whan Ahn ◽  
Dae-Mang Kim
Keyword(s):  
Stress Distribution ◽  
Tibiofemoral Joint ◽  
Photoelastic Analysis

Novel and simplified optimisation pathway using response surface and design of experiments methodologies for dental implants based on the stress of the cortical bone

2021 ◽  
pp. 095441192110253
Author(s):  
João PO Freitas ◽  
Bruno Agostinho Hernandez ◽  
Paulo J Paupitz Gonçalves ◽  
Edmea C Baptista ◽  
Edson A Capello Sousa
Keyword(s):  
Finite Element ◽  
Stress Distribution ◽  
Design Of Experiments ◽  
Cortical Bone ◽  
Response Surface ◽  
Dental Implants ◽  
Finite Element Models ◽  
Long Term Treatment ◽  
Dimensional Finite Element ◽  
Surrounding Bone

Dental implants are widely used as a long-term treatment solution for missing teeth. A titanium implant is inserted into the jawbone, acting as a replacement for the lost tooth root and can then support a denture, crown or bridge. This allows discreet and high-quality aesthetic and functional improvement, boosting patient confidence. The use of implants also restores normal functions such as speech and mastication. Once an implant is placed, the surrounding bone will fuse to the titanium in a process known as osseointegration. The success of osseointegration is dependent on stress distribution within the surrounding bone and thus implant geometry plays an important role in it. Optimisation analyses are used to identify the geometry which results in the most favourable stress distribution, but the traditional methodology is inefficient, requiring analysis of numerous models and parameter combinations to identify the optimal solution. A proposed improvement to the traditional methodology includes the use of Design of Experiments (DOE) together with Response Surface Methodology (RSM). This would allow for a well-reasoned combination of parameters to be proposed. This study aims to use DOE, RSM and finite element models to develop a simplified optimisation analysis method for dental implant design. Drawing on data and results from previous studies, two-dimensional finite element models of a single Branemark implant, a multi-unit abutment, two prosthetic screws, a prosthetic crown and a region of mandibular bone were built. A small number of combinations of implant diameter and length were set based on the DOE method to analyse the influence of geometry on stress distribution at the bone-implant interface. The results agreed with previous studies and indicated that implant length is the critical parameter in reducing stress on cortical bone. The proposed method represents a more efficient analysis of multiple geometrical combinations with reduced time and computational cost, using fewer than a third of the models required by the traditional methods. Further work should include the application of this methodology to optimisation analyses using three-dimensional finite element models.

Evaluation of the accuracy of a novel surgical guide for flapless dental implant placement for immediate loading in edentulous jaws

2021 ◽  
Author(s):  
Giovanni de Almeida Prado Di Giacomo ◽  
Patrícia Cury ◽  
Airton Moreira da Silva ◽  
Jorge Vicente Lopes da Silva ◽  
Carlos Eduardo Pompeo Souto ◽  
...  
Keyword(s):  
Dental Implants ◽  
Dental Implant ◽  
Selective Laser Sintering ◽  
Apical Region ◽  
Virtual Planning ◽  
Surgical Guide ◽  
Implant Placement ◽  
Surgical Guides ◽  
Edentulous Jaws ◽  
Edentulous Jaw

This study was designed to evaluate the accuracy of a novel computer-designed and selectively laser sintered surgical guide for flapless dental implant placement in the edentulous jaw. Fifty dental implants were placed in 11 patients with at least one totally edentulous jaw. Initially, cone-beam computed tomography (CBCT) was performed in each patient to define the virtual position of the dental implants based on the assessment of bone availability and the proposed dental prosthesis. After virtual planning, 3D surgical guides were printed using selective laser sintering. CBCT was repeated after the surgery, and the pre-and postoperative images were overlapped in the CAD software to compare the planned and actual positions of the dental implants using a one-sample t-test. The mean ± angular standard deviation between the long axes of the planned and final dental implant positions was 4.58 ±2.85 degrees; The linear deviation in the coronal position was  0.87 ± 0.49 mm and  in the apical region of the dental implants was 1.37 ± 0.69 mm. These differences were statistically significant (p <0.001). The proposed modifications reduced the deviations, resulting in an improvement in the technique. We were able to place implants and temporary prostheses using the present protocol, taking into account the differences between the planned and final positions of the dental implants.

scholarly journals Rehabilitation of Maxillary Defect Using Zygomatic Implant Retained Obturator

2021 ◽  
Vol 2021 ◽  
pp. 1-5
Author(s):  
Mounika Ayinala ◽  
Gautam Shetty
Keyword(s):  
Hard Palate ◽  
Odontogenic Myxoma ◽  
Prosthetic Rehabilitation ◽  
Implant Placement ◽  
Heat Cure ◽  
Maxillary Defect ◽  
Zygomatic Implants ◽  
And Function ◽  
Zygomatic Implant

Tumors involving the hard palate, maxillary sinus, or nasal cavity require maxillectomy based on the extent of the lesion. Lack of these boundaries affects the speech, esthetics, and masticatory function. Prosthetic rehabilitation of these defects can be done utilizing zygomatic implants. This present case describes the use of a zygomatic implant to retain a maxillary obturator in a 22-year-old male patient following partial maxillectomy (Brown’s Class 2b) due to odontogenic myxoma. A surgical obturator was secured in position subsequent to the implant placement. Following the healing period, an interim obturator using heat cure acrylic was fabricated. Mechanical retention for the definitive obturator was obtained through the ball attachment suspended from the multiunit abutment of the zygomatic implant. The case was followed up closely for a year to evaluate the function of the prosthesis. The prosthetic rehabilitation not only promoted esthetics and function but also improved the patient’s quality of life.

scholarly journals Comparative analysis of reflection photoelasticity in mandible’s segment with or without base

RSBO ◽  
2018 ◽  
Vol 1 (3) ◽  
pp. 156
Author(s):  
Humberto Gennari Filho ◽  
José Vitor Quineli Mazaro ◽  
Marcelo Coelho Goiato ◽  
Karina Helga Leal Turcio ◽  
Andressa Paschoal Amoroso ◽  
...  
Keyword(s):  
Comparative Analysis ◽  
Applied Load ◽  
Central Portion ◽  
Axial Loads ◽  
Isochromatic Fringes ◽  
Photoelastic Model ◽  
To Receive

Introduction and Objective: To analyze if axial loads of 50 N and 100 N, applied on an implant of 3.75 X 10 mm (Conexão-Jaú, SP, Brazil) fixed on the central portion of a prototype of the mandible with and without support base, generate isochromatic fringes of different intensity and ways. Material and methods: The sample was a segment of the mandible with 115 mm in length, 30 mm height,and 12 mm in thickness, from a block of #7 rose wax. This matrix was adapted to a modified articulator in such way that its base could or not keep contact with the lower arm of the articulator, simply by modifying the support axis. An implant was put perpendicular to the segment of the mandible’s body and then the photoelastic model obtained. The healing abutment was screwed to the implant to receive loads from 50 N to 100 N, with the model with or withoutcontact of its base with the inferior arm of the articulator. Results: Alterations in the reflections of the colors was observed when the implants had been submitted to loads of 50 N and 100 N with or without supported base. Conclusion: Based on the results, it can be concluded that during the photoelasticity analyses alterations in the color standards occurred depending on the support of the sample and the applied load.

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