scholarly journals Photoelastic Study of the Effects of Occlusal Surface Morphology on Tooth Apical Stress from Vertical Bite Forces

2004 ◽  
Vol 5 (1) ◽  
pp. 74-93 ◽  
Author(s):  
Mei-Qing Wang ◽  
Min Zhang ◽  
Jun-Hua Zhang
Keyword(s):  
Surface Morphology ◽  
Occlusal Surface ◽  
Posterior Teeth ◽  
Occlusal Contact ◽  
Test Assembly ◽  
Photoelastic Study ◽  
Normal Occlusion ◽  
Occlusal Surfaces ◽  
Mandibular Teeth ◽  
Relationship Of

Abstract The aim of the study was to determine how the morphology of occlusal surfaces might affect occlusal loading that is transferred to the tooth apex. Photoelastic methods were used to assess apical stress generated by seven variations of occlusions. A test assembly with a 2 kg weight was applied to teeth to create a vertical load. By analyzing the direction and magnitude of the apical principle stress under the polar light that was measured at the apexes of mandibular teeth, the occlusal loading position of each tooth and its direction was obtained based on general mechanical principles. It was found distal incline planes (or slopes) of cusps and lingual incline planes (or slope) of buccal cusps of mandibular posterior teeth carried the greatest occlusal load in normal occlusion. In the other six variations of occlusion presented in this study, the principle apical stresses changed more or less as a result of the different occlusal contact relationships. The magnitude of principle apical stress increased considerably in the flat surface occlusion because of the lack of distribution of occlusion loading by the smooth dentition surface. It is concluded the occlusal surface morphology has a significant effect on the direction and magnitude of apical stress. To establish a suitable relationship of occlusion that can conduct favorable occlusal loading physiologically is very important. Citation Wang M, Zhang M, Zhang J. Photoelastic Study of the Effects of Occlusal Surface Morphology on Tooth Apical Stress from Vertical Bite Forces . J Contemp Dent Pract 2004 February;(5)1:074-093.

Prototyping artificial jaws for the robotic dental testing simulator

2008 ◽  
Vol 222 (8) ◽  
pp. 1209-1220 ◽  
Author(s):  
K Alemzadeh ◽  
D Raabe
Keyword(s):  
Degrees Of Freedom ◽  
Force Transducer ◽  
Resin Cement ◽  
Posterior Teeth ◽  
Occlusal Contact ◽  
Six Degrees Of Freedom ◽  
Lower Jaw ◽  
Normal Occlusion ◽  
Occlusal Surfaces ◽  
Artificial Teeth

This paper presents a robot periphery prototyped for the six-degrees-of-freedom robotic dental testing simulator, simulating the wear of materials on dental components, such as individual teeth, crowns, bridges, or a full set of teeth. The robot periphery consists of the artificial jaws and compliance module. The jaws have been reverse engineered and represent a human-like mandible and maxilla with artificial teeth. Each clinically fabricated tooth consists of a crown and glass ceramic roots which are connected using resin cement. Normal clinical occlusion of the artificial jaws assembly was emulated by a dental articulator based on ‘Andrew's six keys to occlusion’. The radii of the von Spee curve, the Monson curve, and the Wilson curve were also measured as important jaw characteristic indicators to aid normal occlusion. A compliance module had to be built between the lower jaw and the robot platform to sustain the fluctuating forces that occur during normal chewing in the occlusal contact areas, where these high bite forces are major causes of dental component failure. A strain gauge force transducer has been integrated into the machined lower jaw, underneath the second molars, to measure axial biting forces applied to the posterior teeth. The experiments conducted have shown that the sensor is able to sense small changes in the compression force satisfactorily, when applied perpendicular to the occlusal surfaces of the teeth.

Comparative Study of Different Materials for Occlusal Matrix Technique in Posterior Teeth

2016 ◽  
Vol 695 ◽  
pp. 50-54
Author(s):  
Adriana Maria Monea ◽  
K. Ivacson A. Csinszka ◽  
Bukhari Csilla ◽  
Gabriela Bereșescu
Keyword(s):  
Dental Materials ◽  
Acrylic Resin ◽  
Ease Of Use ◽  
Resin Cement ◽  
Occlusal Surface ◽  
Posterior Teeth ◽  
Surface Anatomy ◽  
Carious Lesions ◽  
Occlusal Surfaces ◽  
Component Material

Posterior composite restorations are difficult to contour and polish due to their occlusal anatomy and opposing occlusion. Our study describes a technique for duplicating occlusal surface anatomy, using different dental materials that are able to copy anatomic details. The aim of the study was to evaluate the efficiency of occlusal matrix technique, by comparing technical ease of different dental materials. The study was conducted on extracted teeth which had intact occlusal surfaces or initial carious lesions at this level. An impression of the occlusal surface was made prior to cavity preparation, with four different dental materials: a flow composite, a dual-cure resin cement, a temporary acrylic resin (powder and liquid) and a temporary crown and bridge two-component material in a Unidose®. When the last layer of composite has been placed, the occlusal matrix was forced into the uncured composite to replicate the original occlusal surface, instead of performing manual curing and shaping as in the standard approach. Time needed for complete finishing the case, the hardness of each occlusal matrix and the final morphology obtained were evaluated. The main benefits of the occlusal matrix technique are the technical ease of use due to its simplicity and its high accuracy in reconstructing occlusal morphology. Although the shortest time needed for occlusal matrix preparation was for the dual-cure resin cement, the best oclusssal matrix was obtained with the temporary acrylic resin (powder and liquid).

Mastication

2013 ◽  
Author(s):  
Martin E. Atkinson
Keyword(s):  
Occlusal Plane ◽  
Dental Arch ◽  
Posterior Teeth ◽  
Maxillary Molars ◽  
Anterior Teeth ◽  
Occlusal Surfaces ◽  
Mandibular Teeth ◽  
Maxilla And Mandible ◽  
Dynamic Relationships ◽  
Muscles Of Mastication

Now you have an understanding of the anatomy of the maxilla and mandible, the TMJs, and jaw musculature, we can examine how these structures work together to produce the complex actions involved in the biting and chewing of food. Technically, incision is biting a piece from a larger chunk of food and mastication is the grinding down of that piece into smaller components and mixing them with saliva. Mastication is often used to cover both actions. Box 26.1 briefly compares the anatomy of the human dentition to that of other mammals. As well as knowledge of the TMJ, muscles of mastication, and other muscles used in jaw movements, it is necessary to appreciate some aspects of the static and dynamic relationships of the teeth to understand chewing movements. The first thing to notice is the bigger width of the upper dental arch compared to the lower arch, a condition known as anisognathy. In Figure 26.1A , you can see that the maxillary molars overhang the mandibular teeth by half a cusp width so the buccal cusps of the lower molars and premolars occlude between the buccal and palatal cusps of the maxillary teeth. Observe also that the long axis of the maxillary molars and premolars incline buccally while the corresponding axis of the mandibular teeth incline lingually; the occlusal plane of the posterior teeth is thus curved transversely as illustrated in Figure 26.1A . It would be possible to chew food simply by moving the teeth up and down without any side-to-side movement, but this would be inefficient and not make full use of the cusps on the occlusal surfaces of posterior teeth. However, we can only chew on one side at a time because of the anisognathy of the upper and lower teeth. Due to anisognathic jaw positions, the maxillary anterior teeth are also going to protrude in front of the mandibular anterior teeth. Figure 26.1B illustrates the normal relationships of the anterior teeth. The maxillary incisors overhang the mandibular incisors by about 2–3 mm in the horizontal plane; this is called the overjet. The upper incisors usually have a vertical overhang, the overbite, of about the same amount. As mentioned in Chapter 24 , the mouth at rest is closed by tonic contraction of the muscles of mastication and facial expression.

scholarly journals Distances between mandibular posterior teeth and the WALA ridge in Peruvians with normal occlusion

2017 ◽  
Vol 22 (6) ◽  
pp. 56-60 ◽  
Author(s):  
Carla Y. Kong-Zárate ◽  
Marcos J. Carruitero ◽  
Will A. Andrews
Keyword(s):  
Age Groups ◽  
Test Results ◽  
Posterior Teeth ◽  
Normal Occlusion ◽  
Tooth Type ◽  
The Mean ◽  
Student’S T ◽  
Mandibular Posterior Teeth ◽  
Digital Caliper ◽  
Student’S T Test

ABSTRACT Objective: The purposes of this investigation were to determine the horizontal distances between the mandibular posterior teeth and the WALA ridge in a sample of Peruvians with normal occlusion and to compare them by tooth type, sex, arch side, and age groups. Methods: 65 dental casts of subjects with normal occlusion were collected. Posterior teeth, except for third molars, were evaluated. The horizontal distances between the occluso-gingival midpoints of the buccal surfaces (FA points) of each tooth and the WALA ridge were measured using a modified digital caliper. The values between each different tooth type within the sample were compared using the ANOVA and Scheffe tests, while comparisons by sex, arch side and age groups, using the Student’s t-test. Results: The mean distances in the sample was 0.96 mm for first premolars, 1.45 mm for second premolars, 2.12 mm for first molars and 2.55 mm for second molars. Statistically significant differences between each of the four tooth types were found. There were no significant differences found between sex, arch side and age groups. Conclusion: The horizontal distances between the mandibular posterior teeth and the WALA ridge increased progressively from the first premolars to the second molars in Peruvians with normal occlusion. The WALA ridge was a good landmark to evaluate the positions of posterior teeth in Peruvians with normal occlusion.

scholarly journals Versatility of the cone beam computed tomography in oral surgery: an overview

2011 ◽  
Vol 1 (2) ◽  
pp. 31
Author(s):  
Kishan G. Panicker ◽  
Anuroopa Pudukulangara Nair ◽  
Bipin Chandra Reddy
Keyword(s):  
Computed Tomography ◽  
Alveolar Bone ◽  
Oral Surgery ◽  
Cone Beam Ct ◽  
Cone Beam ◽  
Facial Skeleton ◽  
Posterior Teeth ◽  
True Nature ◽  
Root Apices ◽  
Relationship Of

Cone beam CT (CBCT) produces threedimensional information on the facial skeleton, teeth and their surrounding tissues; and is increasingly being used in many of the dental specialties. This is usually achieved with a substantially lower effective dose compared with conventional medical computed tomography (CT). Periapical pathologies, root fractures, root canal anatomy and the true nature of the alveolar bone topography around teeth may be assessed. CBCT scans are desirable to assess posterior teeth prior to periapical surgery, as the thickness of the cortical and cancellous bone can be accurately determined as can the inclination of roots in relation to the surrounding jaw. The relationship of anatomical structures such as the maxillary sinus and inferior dental nerve to the root apices may also be clearly visualized. Measurements on CBCT are more accurate when compared with OPG. Therefore, CBCT permits the clinician to have all necessary information when planning dental implants. The purpose of this article is to provide an overview of the unique image display capabilities of maxillofacial CBCT systems and to illustrate specific applications in clinical practice.

Employing the T-Scan/BioEMG III Synchronized Technologies to Diagnose and Treat Chronic Occluso-Muscle Disorder

2020 ◽  
pp. 362-514
Author(s):  
Robert B. Kerstein, DMD
Keyword(s):  
Periodontal Ligament ◽  
Temporomandibular Disorder ◽  
Surface Friction ◽  
Masticatory Muscles ◽  
Neural Activation ◽  
Clinical Implementation ◽  
Posterior Teeth ◽  
Occlusal Contact ◽  
Muscle Disorder ◽  
Time Reduction

This chapter discusses chronic occluso-muscle disorder, which is a myogenous subset of temporomandibular disorder (TMD) symptoms resultant from occlusally activated muscle hyperactivity. It also describes the computer-guided occluso-muscle disorder treatment known as disclusion time reduction (DTR), that studies repeatedly show reduces many common muscular temporomandibular disorder symptoms. T-Scan-based research since 1991 has determined that a significant etiologic component of occluso-muscle disorder is prolonged (in time) occlusal surface friction shared between opposing posterior teeth during mandibular excursions, that occurs in both normal chewing function and during parafunction. This friction results in prolonged compressions of the periodontal ligament (PDL) fibers of the involved teeth, which when in excursive opposing occlusal contact, also experience pulpal flexure that leads to pulpal neural activation, which together with the periodontal ligament compressions, trigger excess muscle contractions within the masticatory muscles. It is this unique neuroanatomy that incites and perpetuates many chronic muscular TMD symptomatology, that can be readily resolved in patients that meet the diagnostic criteria for DTR candidacy, using the ICAGD coronoplasty that is performed in the maximum intercuspal position (MIP), without employing treatment splints, deprogrammers, appliances, orthotics, or mandibular repositioning. Additionally, this chapter will highlight the newest disclusion time reduction therapy (DTR) studies that support the clinical implementation of this highly effective measured occlusal treatment for occluso-muscle disorder.

scholarly journals The prevalence of malocclusion among 7–15-year-old Lithuanian schoolchildren

Medicina ◽  
2009 ◽  
Vol 45 (2) ◽  
pp. 147 ◽  
Author(s):  
Antanas Šidlauskas ◽  
Kristina Lopatienė
Keyword(s):  
Important Determinant ◽  
Age Groups ◽  
Epidemiological Data ◽  
Dental Arch ◽  
Class Iii ◽  
Posterior Crossbite ◽  
Normal Occlusion ◽  
Dental Crowding ◽  
Relationship Of ◽  
The Relationship

The epidemiological data on the prevalence of malocclusion is an important determinant in planning appropriate levels of orthodontic services. The occurrence of occlusal anomalies varies between different countries, ethnic and age groups. The aim of this study was to describe the prevalence of malocclusion among Lithuanian schoolchildren in the 7–9-, 10– 12-, and 13–15-year age groups assessing occlusal morphology. The study included 1681 schoolchildren aged 7–15 years. The crowding, spacing, overbite, overjet, the relationship of the first upper and lower molars according Angle’s classification, and posterior crossbite were assessed. The study demonstrated that only 257 children had normal occlusion, and 44 had undergone orthodontic treatment among them. The greatest overjet in the studied contingent was 11 mm, and the negative overjet – 3 mm. The overbite ranged between 0 and 6 mm with a mean of 2.29±1.23 mm. Posterior crossbite was recorded in 148 children (8.8%). This study showed that the prevalence of malocclusion among 7–15-year-old Lithuanian schoolchildren is 84.6%. The most common malocclusion was dental crowding. The upper dental arch crowding was registered for 44.1% and lower for 40.3% of all schoolchildren. The class I molar relationship was detected in 68.4% of the subjects, class II – in 27.7%, and class III – in 2.8%.

scholarly journals Normal torque of the buccal surface of mandibular teeth and its relationship with bracket positioning: a study in normal occlusion

2006 ◽  
Vol 17 (2) ◽  
pp. 155-160 ◽  
Author(s):  
Marcelo Antonio Mestriner ◽  
Carla Enoki ◽  
José Nelson Mucha
Keyword(s):  
Orthodontic Treatment ◽  
Small Difference ◽  
Orthodontic Appliances ◽  
Vertical Shift ◽  
Mandibular Tooth ◽  
Normal Occlusion ◽  
History Of ◽  
Mandibular Teeth ◽  
Bracket Positioning ◽  
Mandibular Incisors

This study evaluated the degree of buccolingual inclination of mandibular tooth crowns relative to torque. For such purpose, mandibular and maxillary stone casts from 31 Caucasian Brazilian adults with normal occlusion, pleasant facial aspect and no history of previous orthodontic treatment were examined. A custom device was developed for measuring the degree of inclination (torque) of bracket slots of orthodontic appliances relative to the occlusion plane, at three bonding height: standard (center of clinical crown), occlusal (0.5 mm occlusally from standard) and cervical (0.5 mm cervically from standard). Except for the mandibular incisors, which presented a small difference in torque from one another (lingual root torque for central incisors and buccal root torque for lateral incisors), the remaining average values are close to those found in the literature. Due to the convexity of the buccal surface, the 1-mm vertical shift of the brackets from occlusal to cervical affected the values corresponding to the normal torque, in approximately 2 degrees in central and lateral incisors, 3 degrees in canines and 8 degrees in premolars and molars.

scholarly journals Relationship of Dental Caries and Fluorosis to Fluoride Supplement History in a Non-Fluoridated Sample of Schoolchildren

1989 ◽  
Vol 3 (2) ◽  
pp. 161-167 ◽  
Author(s):  
R.A. Bagramian ◽  
S. Narendran ◽  
M. Ward
Keyword(s):  
Odds Ratio ◽  
Response Rate ◽  
Dental Fluorosis ◽  
Tooth Surface ◽  
Caries Experience ◽  
Significant Relation ◽  
Posterior Teeth ◽  
Supplement Use ◽  
Tooth Surfaces ◽  
Relationship Of

A random sample of 206 Michigan children, aged from 9 to 13, were examined for fluorosis from a larger group of 2038 children participating in a dental project. Clinical examinations included caries data (DMFS) and assessment of fluorosis by use of the Tooth Surface Index of Fluorosis (TSIF). Separate examiners were used for each index. The response rate of a questionnaire mailed to parents to gather information on residence histories, use of fluoride supplements, and antibiotics was 78%. The prevalence of fluorosis was about 20% among the respondents. Of the 4868 tooth surfaces examined, 9.2% were affected by fluorosis. In all cases, dental fluorosis was judged as mild, with most occurrences on the posterior teeth. No instances of moderate or severe fluorosis were found. The caries experience of respondents was 1.69 ± 2.73 DMFS. Caries experience does not appear to be significantly related to income, education, or fluoride supplement use. Approximately 52% of respondents were reported to have taken fluoride supplements with various degrees of consistency. Parents' education was positively related to both prevalence of fluorosis (odds ratio = 2.2) and use of fluoride supplements (odds ratio = 2.7). No significant relation was revealed with evidence of fluorosis and use of supplements. This study shows a relatively mild level of dental fluorosis in a sample of children from a non-fluoridated area. Dental fluorosis in this group does not appear to be related to use of fluoride supplements or differences in caries experience.

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