scholarly journals Comparison of occlusal contact areas of class I and class II molar relationships at finishing using three-dimensional digital models

2015 ◽  
Vol 45 (3) ◽  
pp. 113 ◽  
Author(s):  
Hyejoon Lee ◽  
Minji Kim ◽  
Youn-Sic Chun
Keyword(s):  
Three Dimensional ◽  
Class Ii ◽  
Class I ◽  
Digital Models ◽  
Occlusal Contact ◽  
Contact Areas

scholarly journals Evaluation of Occlusal Contacts among Different Groups of Malocclusion using 3D Digital Models

2014 ◽  
Vol 15 (1) ◽  
pp. 46-55 ◽  
Author(s):  
Naim Z Al-Rayes ◽  
Mohammad Y Hajeer
Keyword(s):  
Class Ii ◽  
Sexual Differences ◽  
Class I ◽  
Stepwise Multiple Regression ◽  
Regression Equations ◽  
Class Iii ◽  
Digital Models ◽  
Arch Width ◽  
Division 1 ◽  
3D Digital Models

ABSTRACT Objectives (1) To evaluate the applicability of using 3D digital models in the assessment of the magnitude of occlusal contacts by measuring occlusal contact surface areas (OCSAs) and 3D mesh points in ‘contact’ (OCMPs) in a sample of orthodontic patients; (2) To detect any sex differences in the magnitude of occlusal contacts in all malocclusion groups; (3) To detect intergroup differences; (4) To assess possible correlations between occlusal contacts and other dental characteristics. Materials and methods Study casts of 120 malocclusion patients were selected and divided into 4 groups (class I division 1, class II division 1, class II division 2, class III) with equal numbers for both sexes. 3D digital models were produced using O3DM™ technology. Occlusal contacts were quantified using two methods of measuring. Results (1) No significant sexual differences were detected for OCMPs (mesh points) and OCSAs (mm2) in all groups. (2) There were statistically significant differences among malocclusion groups for OCMPs and OCSAs (p < 0.001). Tukey's HSD posthoc tests showed that class III patients had significantly less occlusal contacts than other malocclusion groups. (3) Stepwise multiple regression equations showed that overjet, lower arch width and overbite could explain approximately 19.5% of the total variance of OCSAs and OCMPs. Conclusion Sexual differences in occlusal contacts were not detected. Class I division 1 patients had the highest amount of occlusal contacts among all groups of malocclusion. Overjet, overbite and lower dental arch width were best predictors of occlusal contacts in the current sample. How to cite this article Al-Rayes NZ, Hajeer MY. Evaluation of Occlusal Contacts among Different Groups of Malocclusion using 3D Digital Models. J Contemp Dent Pract 2014;15(1):46-55.

scholarly journals Purification and Crystallization Reveal Two Types of Interactions of the Fusion Protein Homotrimer of Semliki Forest Virus

2004 ◽  
Vol 78 (7) ◽  
pp. 3514-3523 ◽  
Author(s):  
Don L. Gibbons ◽  
Brigid Reilly ◽  
Anna Ahn ◽  
Marie-Christine Vaney ◽  
Armelle Vigouroux ◽  
...  
Keyword(s):  
Fusion Protein ◽  
Fusion Proteins ◽  
Semliki Forest Virus ◽  
Three Dimensional ◽  
Class Ii ◽  
Class I ◽  
Structural Basis ◽  
Viral Fusion ◽  
Purification Method ◽  
Viral Fusion Proteins

ABSTRACT The fusion proteins of the alphaviruses and flaviviruses have a similar native structure and convert to a highly stable homotrimer conformation during the fusion of the viral and target membranes. The properties of the alpha- and flavivirus fusion proteins distinguish them from the class I viral fusion proteins, such as influenza virus hemagglutinin, and establish them as the first members of the class II fusion proteins. Understanding how this new class carries out membrane fusion will require analysis of the structural basis for both the interaction of the protein subunits within the homotrimer and their interaction with the viral and target membranes. To this end we report a purification method for the E1 ectodomain homotrimer from the alphavirus Semliki Forest virus. The purified protein is trimeric, detergent soluble, retains the characteristic stability of the starting homotrimer, and is free of lipid and other contaminants. In contrast to the postfusion structures that have been determined for the class I proteins, the E1 homotrimer contains the fusion peptide region responsible for interaction with target membranes. This E1 trimer preparation is an excellent candidate for structural studies of the class II viral fusion proteins, and we report conditions that generate three-dimensional crystals suitable for analysis by X-ray diffraction. Determination of the structure will provide our first high-resolution views of both the low-pH-induced trimeric conformation and the target membrane-interacting region of the alphavirus fusion protein.

scholarly journals Influence of Occlusal Contact Area on Cusp Deflection and Stress Distribution

2014 ◽  
Vol 15 (6) ◽  
pp. 699-704 ◽  
Author(s):  
Anna Karina Figueiredo Costa ◽  
Thaty Aparecida Xavier ◽  
Tarcisio José Arruda Paes-Junior ◽  
Oswaldo Daniel Andreatta-Filho ◽  
Alexandre Luiz Souto Borges
Keyword(s):  
Stress Distribution ◽  
Contact Area ◽  
Three Dimensional ◽  
Great Influence ◽  
Maximum Principal Stress ◽  
Occlusal Surface ◽  
Load Application ◽  
Element Analysis ◽  
Occlusal Contact ◽  
Contact Areas

ABSTRACT Objective The purpose of this study was to evaluate the effect of occlusal contact area for loading on the cuspal deflection and stress distribution in a first premolar restored with a high elastic modulus restorative material. Materials and methods The Rhinoceros 4.0 software was used for modeling the three-dimensional geometries of dental and periodontal structures and the inlay restoration. Thus, two different models, intact and restored teeth with three occlusal contact areas, 0.1, 0.5 and 0.75 mm2, on enamel at the occlusal surface of buccal and lingual cusps. Finite element analysis (FEA) was performed with the program ANSYS (Workbench 13.0), which generated a mesh with tetrahedral elements with greater refinement in the regions of interest, and was constrained at the bases of cortical and trabecular bone in all axis and loaded with 100 N normal to each contact area. Results To analysis of maximum principal stress, the smaller occlusal contact area showed greater compressive stress in region of load application for both the intact and inlay restored tooth. However, tensile stresses at the occlusal isthmus were similar for all three tested occlusal contact areas (60 MPa). To displacement of the cusps was higher for teeth with inlay (0.46- 0.48 mm). For intact teeth, the smaller contact area showed greater displacement (0.10 mm). For teeth with inlays, the displacement of the cusps were similar in all types of occlusal area. Conclusion Cuspal displacement was higher in the restored tooth when compared to the intact tooth, but there were no significant variations even with changes in the occlusal contact area. Relevance clinical Occlusal contacts have a great influence on the positioning of teeth being able to maintain the position and stability of the mandible. Axial loads would be able to generate more uniform stress at the root presenting a greater concentration of load application in the point and the occlusal surface. Thus, is necessary to analyze the relationship between these occlusal contacts as dental wear and subsequent occlusal interferences. How to cite this article Costa AKF, Xavier TA, Paes-Junior TJA, Andreatta-Filho OD, Borges ALS. Influence of Occlusal Contact Area on Cusp Deflection and Stress Distribution. J Contemp Dent Pract 2014;15(6):699-704.

scholarly journals Influence of Sagittal Root Positions on the Stress Distribution Around Custom-made Root-analogue Implants: A Three-dimensional Finite Element Analysis

2021 ◽  
Author(s):  
Chunping Lin ◽  
Hongcheng Hu ◽  
Junxin Zhu ◽  
Yuwei Wu ◽  
Qiguo Rong ◽  
...  
Keyword(s):  
Stress Concentration ◽  
Three Dimensional ◽  
Class Ii ◽  
Class I ◽  
Von Mises Stress ◽  
Class Iii ◽  
Element Analysis ◽  
Custom Made ◽  
Root Position ◽  
Von Mises

Abstract Background: Stress concentration may cause bone resorption even lead to the failure of implantation. This study was designed to investigate whether a certain sagittal root position could cause stress concentration around maxillary anterior custom-made root-analogue implants via three-dimensional finite element analysis.Methods: Six models were constructed and divided into two groups. The smooth group included models of unthreaded custom-made implants in Class I, II or III sagittal root positions. The threaded group included models of reverse buttress-threaded implants in the three positions. Stress distributions under vertical and oblique loads of 100 N were analyzed.Results: Stress concentrations around the labial lamella area were more prominent in the Class I position than in the Class II and Class III positions under oblique loading. Under vertical loading, the most obvious stress concentration areas were the labial lamella and palatal apical areas in the Class I and Class III positions, respectively. Stress was relatively distributed in the labial and palatal lamellae in the Class II position. The maximum von Mises stress in the bone around the custom-made root-analogue implants in this study was lower than around traditional implants reported in the literature. Additionally, compared to the smooth group, the threaded group showed lower von Mises stress in the bone around the implants.Conclusions: The sagittal root position affected the von Mises stress distribution around custom-made root-analogue implants. There was no certain sagittal root position that could cause excessive stress concentration around the custom-made root-analogue implants. Among the three sagittal root positions, the Class II position would be the most appropriate site for custom-made root-analogue implants.

scholarly journals Three-dimensional comparative evaluation of articular disc position and other temporomandibular joint morphology in Class II horizontal and vertical cases with Class I malocclusion:

2020 ◽  
Vol 90 (5) ◽  
pp. 707-714
Author(s):  
Zynul Ali Sirsmith John ◽  
Sunita S. Shrivastav ◽  
Ranjit Kamble ◽  
Eshita Jaiswal ◽  
Rajasbala Dhande
Keyword(s):  
Temporomandibular Joint ◽  
Orthodontic Treatment ◽  
Sagittal Plane ◽  
Three Dimensional ◽  
Class Ii ◽  
Class I ◽  
Articular Disk ◽  
Disc Position ◽  
Condylar Position ◽  
Mri Evaluation

ABSTRACT Objective To evaluate and compare articular disk position, condylar position, and joint spaces in Class II vertical, Class II horizontal, and Class I cases. The purpose was to assess the potential for development of temporomandibular disorders (TMDs) in the three groups. Materials and Methods A sample of 75 cases, 25 cases in each group of Class I, Class II vertical, and Class II horizontal, were selected based on inclusion and exclusion criteria. Magnetic resonance imaging (MRI) assessments were made with a 1.5-Tesla basic system with a closed-mouth technique for evaluating articular disk position in the sagittal and transverse planes, condylar position, and joint spaces in the sagittal plane. Philips 3.0 software was used to analyze the MR images. Results There was evidence of alterations in the temporomandibular joint (TMJ) morphology in both Class II vertical and Class II horizontal cases, with maximum discrepancy in Class II vertical cases. MRI evaluation suggested a tendency for antero-medial disk displacement with anteriorly positioned condyles in Class II vertical cases. The discrepancy was milder in the Class II horizontal group. Conclusions Class II vertical cases are more susceptible to the development of TMDs and should be subjected to TMJ evaluation before starting any orthodontic treatment to intercept and prevent a mild asymptomatic TMD from developing into a more severe form. Class II vertical cases should be subjected to MRI evaluation before starting any orthodontic treatment.

scholarly journals Three-dimensional study of the upper airway in different skeletal Class II malocclusion patterns

2018 ◽  
Vol 89 (1) ◽  
pp. 93-101
Author(s):  
Fernando C. Brito ◽  
Daniel P. Brunetto ◽  
Matilde C. G. Nojima
Keyword(s):  
Linear Regression Analysis ◽  
Three Dimensional ◽  
Upper Airway ◽  
Class Ii ◽  
Class I ◽  
Class Ii Malocclusion ◽  
Skeletal Class ◽  
Skeletal Class Ii ◽  
Intergroup Comparison ◽  
Reconstruction Software

ABSTRACT Objectives: To characterize upper airway volume and morphology in patients with different skeletal patterns of Class II malocclusion compared to Class I. Materials and Methods: A total of 197 individuals who had cone-beam computed tomography were allocated into groups according to ANB, SNA, and SNB angles (Class I, Class II maxillary protrusion, Class II mandibular retrusion), each subdivided into hypodivergent, normal, and hyperdivergent. Nasopharynx (NP), oropharynx (OP), and hypopharynx (HP) were assessed with three-dimensional image reconstruction software. Results: Intergroup comparison did not detect significant differences in volume and morphology of NP, OP, and HP. The males displayed larger OP and HP volume than the females. Positive correlations between age and NP, OP, HP volume and between craniocervical angle and OP and HP volume were observed. Linear regression analysis detected a tendency for OP and HP volume to increase as maxillary and mandibular length increased. Conclusions: Upper airway volume and morphology were similar in different skeletal patterns of Class II malocclusion. Actual upper and lower jaw lengths were more closely related to upper airway volume and morphology than the angles that reflected their position relative to the cranial base.

scholarly journals Analysis of Three-Dimensional Morphological Differences in the Mandible between Skeletal Class I and Class II with CBCT Fixed-Point Measurement Method

Scanning ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-9
Author(s):  
Qiang Dong ◽  
HaoYu Shi ◽  
Qi Jia ◽  
Yueyi Tian ◽  
Keqian Zhi ◽  
...  
Keyword(s):  
Anterior Part ◽  
Three Dimensional ◽  
Morphological Characteristics ◽  
Vertical Direction ◽  
Class Ii ◽  
Class I ◽  
Skeletal Class ◽  
Skeletal Class Ii ◽  
Mandibular Body

This study was aimed at determining the three-dimensional differences in the mandible morphology between skeletal class I and II patients, at exploring the pathogenic mechanisms and morphological characteristics of skeletal class II, and at providing clinical references. The subjects were assigned to two groups according to the size of ANB angle: skeletal class I ( 2 ° < ANB   angle < 5 ° ) and skeletal class II ( 5 ° < ANB   angle < 8 ° ). After cone-beam computed tomography (CBCT) scanning, 31 landmarks and 25 measurement items were determined by In Vivo Dental 5.1 software (Anatomage, CA) for statistical analysis. The results were as follows: Co-Go, Go-Me, and CdM-CdD in skeletal class II cases were smaller than those in skeletal class I, and GoR-Me-GoL, GoR-Me-CoL, and, Ig-Men were larger than those in skeletal class I cases. In conclusion, there were significant differences in the three-dimensional morphology of the mandible between skeletal class I and class II patients. The vertical growth of the ramus, the horizontal growth of the mandibular body, and the condyle in skeletal class II patients were smaller than those in skeletal class I cases. In skeletal class II, the growth of the anterior part of the mandible in the vertical direction was larger than that in skeletal class I, and the shape of the mandible was more extended.

scholarly journals Digital analysis of tooth sizes among individuals with different malocclusions: A study using three-dimensional digital dental models

2021 ◽  
Vol 104 (3) ◽  
pp. 003685042110381
Author(s):  
Beyza Karadede Ünal ◽  
Deniz Dellaloğlu
Keyword(s):  
Three Dimensional ◽  
Class Ii ◽  
Tooth Size ◽  
Digital Models ◽  
Three Dimensional Model ◽  
Digital Format ◽  
Significant Difference ◽  
Three Dimensional Measurement ◽  
Anterior Ratio ◽  
Overall Ratio

Objective: It is aimed to examine the tooth sizes of digital models of patients with different malocclusions with the help of three-dimensional measurement software. Methods: Digital models of 252 patients aged between 13 and 25 years of age were included. According to the Angle classification, three different malocclusion groups were allocated such that there were 84 patients in each group, plaster models of patients scanned with the three-dimensional model browser 3Shape R700 3D Scanner (3Shape A/S Copenhagen, Denmark) and transferred to the digital format. 3Shape Ortho Analyzer (3Shape A/S Copenhagen, Denmark) software was used for making the necessary tooth size measurements. Results: When the measurements were evaluated, it was determined that significant changes occurred between tooth sizes of individuals with different malocclusions. Generally, higher values were observed in mesiodistal and buccolingual tooth dimensions of class II individuals compared to other groups. There was no difference between the groups in the anterior ratio values, but when the overall ratio values were evaluated among the groups, a statistically significant difference was determined. Class II malocclusion group was found to have a significantly lower overall ratio of occurrence. Conclusion: Individuals with different malocclusions differ in tooth size.

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