scholarly journals Optical metrology analysis of the lower jaw deformations

2011 ◽  
Vol 68 (4) ◽  
pp. 336-340 ◽  
Author(s):  
Ivan Tanasic ◽  
Ljiljana Tihacek-Sojic ◽  
Aleksandra Milic-Lemic
Keyword(s):  
Optical Metrology ◽  
Dental Arch ◽  
Digital Cameras ◽  
Full Field ◽  
Second Molar ◽  
Biomechanical Behavior ◽  
Lower Jaw ◽  
Bone Strains ◽  
Applied Forces ◽  
Lower Premolar

Background/Aim. New optical stereometric methods based on both contact and noncontact mechanisms for displacement measurement have become common methods in biomechanical behavior research of biomaterials, bone and soft tissue. The aim of this study was to register and measure possible deformations of the lower jaw (mandible) with the intact dental arch using optical metrology method. Methods. The system for full field measurement of deformations (strains) comprised of two digital cameras for a synchronized stereoview of the specimen, and the Aramis software. Results. The maximum mandibular bone strains were measured in the regions of the lower first premolar and the lower second molar. In the action force of 500 N simulated in the region of the first lower premolar the intensity of deformation was 86 ?m. The value of maximum strain in the bone around the molars was 24 ?m for the force of 500 N acting on the second lower molar. When it comes to premolars, 3-5 times stronger deformation was observed in the region of the first lower premolar, compared to the deformation values of the second lower premolar area. Conclusion. Under loading of the applied forces the measured strains were in the elastic deformation area, meanning that the dependence of force and deformity is linear. The highest values of strain measurements obtained by the optical method were found in the jaw bone tissue around the loading teeth, and the bony regions of the triangle and mental region. According to the obtained results from the Aramis processing software it can be concluded that this method is applicable in a variety of biomedical research.

scholarly journals Morphometric regularities of the depth indices of dental arches in the mesocrane skull type

2018 ◽  
Vol 9 (4) ◽  
pp. 28-32
Author(s):  
E. Y. Efmova
Keyword(s):  
Morphometric Parameters ◽  
Cutting Edge ◽  
Clinical Aspects ◽  
Dental Arch ◽  
Men And Women ◽  
Lower Jaw ◽  
Upper Jaw ◽  
Point Of Intersection

Objective: to reveal the morphometric regularities of the depth indices of the dental arches of the upper and lower jaws of the mesocrane skull type.Material and methods: the morphometric parameters of the depth of the dental arches of the upper and lower jaws were investigated. Te work was performed on 144 preparations of mesocrane skull type of people of both sexes of mature age with physiological occlusion of teeth. Te depth of the dental arch was measured from the point located at the center of the cutting edge of the medial incisor to the point of intersection with the line connecting the distal surfaces of the tooth crowns at the level of the canines, frst premolars, second premolars, frst molars, and second molars.Results: the range of confdence limits of the depth of the dental arches of the upper jaw in men at the level of canines and premolars surpassed those of women. Te range of confdence limits of the depth of the dental arches of the lower jaw in men and women at all levels of measurement was similar.Conclusions: the indices of the confdence limits of the depth of the vestibular and palatal dental arches of the upper and lower jaws are revealed. Te new data obtained as a result of the research, supplement and expand the information on the studied parameters, both in theoretical and clinical aspects.

Overlap of the Primary Dentition in Children

2009 ◽  
Vol 33 (3) ◽  
pp. 269-274
Author(s):  
Issei Saitoh ◽  
Haruaki Hayasaki ◽  
Emi Inada ◽  
Tomoaki Maruyama ◽  
Yoshihiko Takemoto ◽  
...  
Keyword(s):  
Three Dimensional ◽  
Primary Dentition ◽  
Dental Arch ◽  
Second Molar ◽  
Dental Models ◽  
Arch Forms ◽  
Best Fit ◽  
Single Coordinate ◽  
Variable Measurement ◽  
Primary Canine

Objective: The aim of the present study was to estimate the amount of overlap in children with the primary dentition. Study design: The sample consisted of 20 Japanese boys between 3 and 5 years of age (mean age:4years 10 months). Landmarks on their maxillary and mandibular dental models were digitized using a three-dimensional mechanical digitizer in a single coordinate system. Multilevel statistical models created best-fit polynomial curves to determine overbite, overjet and buccal height of all primary teeth and describe the dental arch forms. Results: No significant side differences were detected. The primary canine showed the largest overbite (1.87 mm) and buccal height (9.07 mm). The primary second molar exhibited the largest ovejet (2.76 mm). Buccal height was the least variable measurement. Conclusion: Occlusal relationships of the primary dentition were evaluated in 3-dimensions, establishing overlap variables for clinical diagnosis and treatment planning.

Full-field dynamic deformation and strain measurements using high-speed digital cameras

2005 ◽  
Author(s):  
Timothy E. Schmidt ◽  
John Tyson ◽  
Konstantin Galanulis ◽  
Duane M. Revilock ◽  
Matthew E. Melis
Keyword(s):  
High Speed ◽  
Dynamic Deformation ◽  
Digital Cameras ◽  
Full Field ◽  
Strain Measurements ◽  
Field Dynamic

Second Molar Extraction in the Treatment of Lower Premolar Crowding

1992 ◽  
Vol 19 (4) ◽  
pp. 299-304 ◽  
Author(s):  
Margaret E. Richardson ◽  
Donald J. Burden
Keyword(s):  
Second Molar ◽  
Lower Arch ◽  
Lower Premolar ◽  
Molar Extraction

Thirty-four children with lower premolar crowding were treated by extraction of second molars. Thirteen cases had mechanical lower arch treatment started not less than 6 months after extractions. The remainder had no treatment in the lower arch. The change in premolar crowding was measured, and the reasons why spontaneous alignment occurred in some cases and not in others were examined.

scholarly journals Similar biomechanical properties of four tripled tendon graft models for ACL reconstruction

2021 ◽  
Author(s):  
Davide Pavan ◽  
Federica Morello ◽  
Francesco Monachino ◽  
Giuseppe Rovere ◽  
Lawrence Camarda ◽  
...  
Keyword(s):  
Acl Reconstruction ◽  
Testing Machine ◽  
Thermoelastic Stress ◽  
Fatigue Loading ◽  
Biomechanical Properties ◽  
Simultaneous Increase ◽  
Full Field ◽  
Biomechanical Behavior ◽  
Significant Difference ◽  
Group 2

Abstract Purpose The present study tested and compared the biomechanical properties of four different triplicate graft tendon techniques. Methods 32 tripled tendons from the common extensor muscle of bovine fingers were tested on a material testing machine, passing the end loop over a metal rod of a clevis connected to the load cell on the upper side, and fixing the lower end to a clamp. The samples were divided into four groups: (A) tripled with a free end sutured only to one of the two fixed bundles (B) tripled with a free end positioned between the two fixed strands and sutured to both (C) tripled with an S-shape and all the three strands sutured together at the upper and lower extremities of the graft (D) partially quadrupled with the free end sutured together with the other three bundles at the upper extremity. Each sample was pretensioned at 50 N for 10 min and then subjected to 1000 load control cycles between 50 and 250 N. Finally, each sample was subjected to a load to failure test. Authors also present some preliminary results on the feasibility of a non-contact and full-field Thermoelastic Stress Analysis technique, based on Infrared Thermography, to evaluate the level of stress on the whole graft, and hence on each strand, during fatigue loading. Results Eighty five percent of the samples failed at the level of the clamp. The cyclical elongation progressively decreased in all the samples and there was a simultaneous increase in stiffness. An increased stiffness was noted between Group 2 vs Group 3 and Group 2 vs Group 4 at the 500th and 1000th cycle. The failure loads were as follows: (a) 569.10 N, (b) 632.28 N, (c) 571.68 N, (d) 616.95 N. None of the parameters showed a statistically significant difference between the four groups. Conclusion This study reported similar biomechanical behavior of four different models of tripled grafts suitable for ACL reconstruction. In addition, the biomechanics of overall tripled tendon grafts seems more affected by the viscoelastic property of the tendon itself rather than the preparation method.

scholarly journals Utilization of residual space of deciduous second molar to align teeth in a crowded arch

2020 ◽  
Vol 19 (4) ◽  
pp. 763-768
Author(s):  
Kamrun Nessa ◽  
Nabila Anwar ◽  
Ranjit Ghosh ◽  
Sonali Mondal ◽  
Mohammad Khursheed Alam
Keyword(s):  
Case Report ◽  
Medical Science ◽  
Female Adolescent ◽  
Mixed Dentition ◽  
Adolescent Patient ◽  
Second Molar ◽  
Lower Jaw ◽  
Residual Space ◽  
Deciduous Molar ◽  
Critical Aspects

The decision forutilization of a space of a retained deciduous molar to alleviate crowding in late mixed dentition is one of the critical aspects in orthodontic treatment.Hence, the aimof the treatment hereis to use the extraction spaces properly to relieve severe crowding and align both the arches to the point where a stable overjet/overbite exist. This case report presenting a 13-year-old female adolescent with severe crowding in both upper and lower jaw and a convex profile. Although she was initially anxious to extract her teeth to treat her case but also she was looking for desirable results. The case was later treated in a conventional orthodontic approach with extraction ofthree 1stpremolars. It was quite challenging to make the best use of the space of missing lower right 2nd premolar after extraction of deciduous second molar on that sideto relieve severe crowding. However; at the end of the treatment, the patient expressed satisfaction with the results- proper bite, smile and most importantly esthetics. This case report demonstrates successful treatment of an adolescent patient with severe crowding by proper utilization of the extraction spaces. Bangladesh Journal of Medical Science Vol.19(4) 2020 p.763-768

Probabilistic Vision-Based Full-Field Displacement and Strain Measurement via Uncertainty Propagation

2012 ◽  
Author(s):  
Tomonari Furukawa ◽  
Yoshitaka Wada ◽  
John G. Michopoulos ◽  
Athanasios Iliopoulos
Keyword(s):  
Field Measurement ◽  
Uncertainty Propagation ◽  
Measurement Techniques ◽  
Digital Cameras ◽  
Strain Fields ◽  
Full Field ◽  
Validation Standard ◽  
Triangular Elements ◽  
Nodal Displacements ◽  
Continuous Field

This paper presents formulations that enable the vision-based measurement of displacement and strain fields extensively in a probabilistic manner. The proposed formulations are built on the dot centroid tracking (DCT) method by digital cameras, which measures the darkness of each pixel in gray scale, identify dots marked on a specimen, derives dot centroids using pixel darkness information and derives displacement and strain fields by tracking the centroids and interpolating the nodal displacements and strains. Under the Gaussian assumption, the proposed formulations analytically propagate the standard deviation of uncertainty in darkness measurement and estimate that in the displacement and strain field measurement. As the first step, the formulations were completed for continuous field measurement with triangular elements. Most advantageously, the proposed formulations allow discussion on measurement error bounds, which also enables the quantitative comparison of the DCT method to the other measurement techniques. For numerical validation, standard deviations of nodal displacements and strains estimated from the known darkness uncertainty were compared to those derived from large samples created with the same darkness uncertainty. The results show the validity of the proposed formulations and their potential in measurement with reliability.

scholarly journals Taking advantage of an unerupted third molar: a case report

2017 ◽  
Vol 22 (4) ◽  
pp. 97-101 ◽  
Author(s):  
Igor Figueiredo Pereira ◽  
Fernando Zander Mucci Santiago ◽  
Augusto Cesar Sette-Dias ◽  
Vladimir Reimar Augusto de Souza Noronha
Keyword(s):  
Root Resorption ◽  
Third Molar ◽  
Dental Arch ◽  
Third Molars ◽  
Supernumerary Tooth ◽  
Proper Position ◽  
Dental Surgery ◽  
Second Molar ◽  
The Third ◽  
Permanent Molar

ABSTRACT Introduction: Treatments with dental surgery seek to displace tooth to the correct position within the dental arch. Objective: To report a clinical case that took advantage of an unerupted third molar. Case history: A male patient, 18 years of age, was referred by his dentist to evaluate the third molars. The clinical exam revealed no visible lower third molars. The computed tomography (CT) exam showed the presence of a supernumerary tooth in the region of the mandibular ramus, on the left side, and impaction of the third molar, which was causing root resorption on the second molar, thus making it impossible to remain in the buccal cavity. The preferred option, therefore, was to remove both second molar and the supernumerary tooth, in addition to attaching a device to the third molar during surgery for further traction. Results: After 12 months, the third molar reached the proper position. Conclusion: When a mandibular second permanent molar shows an atypical root resorption, an impacted third molar can effectively substitute the tooth by using an appropriate orthodontic-surgical approach.

scholarly journals Buccolingual Inclination of Canine and First and Second Molar Teeth and The Curve of Wilson in Different Sagittal Skeletal Patterns of Adults Using Cone-Beam Computed Tomography

2020 ◽  
Author(s):  
Amin Golshah ◽  
Navid Rezae ◽  
Sara Heshmati
Keyword(s):  
Computed Tomography ◽  
Cone Beam Computed Tomography ◽  
Class Ii ◽  
Class I ◽  
Cone Beam ◽  
Dental Arch ◽  
Cross Sectional ◽  
Second Molar ◽  
Molar Teeth ◽  
The Mean

Abstract Background: This study aimed to assess the buccolingual inclination of canine and first and second molar teeth and the curve of Wilson in different sagittal skeletal patterns in untreated adults using cone-beam computed tomography (CBCT). Methods: Sixty-six CBCT scans of adults (mean age: 28.74±5.25 years) were evaluated in this cross-sectional study. The images were standardized using the Frankfurt horizontal plane and the interorbital line. The sagittal skeletal pattern was determined using the ANB angle and Wits appraisal. Inclination angles were measured by NNT Viewer and Mimics software. The curve of Wilson was measured by connecting the tips of mesiobuccal and mesiolingual cusps of maxillary first and second molars along the buccal groove and measuring the formed angle. Data were analyzed using ANOVA. Results: The intraobserver agreement was 0.969. The mean inclination of maxillary first and second molars in class I and III patients was significantly higher than that in class II patients (P<0.05). The mean inclination of mandibular first and second molars in class II patients was significantly higher than that in class I and III patients (P<0.05). The difference in inclination of maxillary and mandibular canine teeth was not significant (P>0.05). The mean curve of Wilson in second molars of class II patients was significantly higher than that in class I patients (P<0.05). Conclusion: In different sagittal skeletal patterns, a compensatory relationship exists between the opposing teeth, which along with the standards of crowns, can be used to determine the appropriate position of teeth in dental arch.

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