Search results for: tooth anatomy

Authors: H. K. Sachidananda, K. Raghunandana, B. Shivamurthy

Abstract:

The estimation of gear tooth stiffness is important for finding the load distribution between the gear teeth when two consecutive sets of teeth are in contact. Based on dynamic model a C-program has been developed to compute mesh stiffness. By using this program position dependent mesh stiffness of spur gear tooth for various profile shifts have been computed for a fixed center distance and altering tooth-sum gearing (100 by ± 4%). It is found that the C-program using dynamic model is one of the rapid soft computing technique which helps in design of gears. The mesh tooth stiffness along the path of contact is studied for both 20° and 25° pressure angle gears at various profile shifts. Better tooth stiffness is noticed in case of negative alteration tooth-sum gears compared to standard and positive alteration tooth-sum gears. Also, in case of negative alteration tooth-sum gearing better mesh stiffness is noticed in 20° pressure angle when compared to 25°.

Keywords: altered tooth-sum gearing, bending fatigue, mesh stiffness, spur gear

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Authors: Priyakant Vaghela, Jagdish Prajapati

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Bending stress at the root of the gear tooth is the very important criteria in gear design and it should be kept the minimum. Minimization of bending stress at the root of the gear tooth is a recent demand from industry. This paper presents an innovative approach to obtain minimum bending stress at the root of a tooth by optimizing tooth root profile and drive side pressure angle. Circular-filleted at the root of the tooth is widely used in the design. Circular fillet creates discontinuity at the root of the tooth. So, at root stress concentration occurs. In order to minimize stress concentration, an important criterion is a G2 continuity at the blending of the gear tooth. A Bezier curve is used with G2 continuity at the root of asymmetric spur gear tooth. The comparison has been done between normal and modified tooth using ANSYS simulation. Tooth root profile and drive side pressure angle are optimized to minimize bending stress at the root of the tooth of the asymmetric involute spur gear. Von Mises stress of optimized profile is analyzed and compared with normal profile symmetric gear. Von Mises stress is reducing by 31.27% by optimization of drive side pressure angle and root profile. Stress concentration of modified gear was significantly reduced.

Keywords: asymmetric spur gear tooth, G2 continuity, pressure angle, stress concentration at the root of tooth, tooth root stress

Procedia PDF Downloads 156

Authors: Hao-Yuan Tseng, Chuan-Yang Chang, Ying-Hui Chen, Sheng-Che Chen, Chih-Han Chang

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Orthodontic tooth treatment has demonstrated a high success rate in clinical studies. It has been agreed upon that orthodontic tooth movement is based on the ability of surrounding bone and periodontal ligament (PDL) to react to a mechanical stimulus with remodeling processes. However, the mechanism of the tooth movement is still unclear. Recent studies focus on the simple principle compression-tension theory while rare studies directly measure tooth movement. Therefore, tracking tooth movement information during orthodontic treatment is very important in clinical practice. The aim of this study is to investigate the mechanism responses of the tooth movement during the orthodontic treatments. A stereovision system applied to track the tooth movement of the patient with the stamp brackets. The system was established by two cameras with their relative position calibrate. And the orthodontic force measured by 3D printing model with the six-axis load cell to determine the initial force application. The result shows that the stereovision system accuracy revealed the measurement presents a maximum error less than 2%. For the study on patient tracking, the incisor moved about 0.9 mm during 60 days tracking, and half of movement occurred in the first few hours. After removing the orthodontic force in 100 hours, the distance between before and after position incisor tooth decrease 0.5 mm consisted with the release of the phenomenon. Using the stereovision system can accurately locate the three-dimensional position of the teeth and superposition of 3D coordinate system for all the data to integrate the complex tooth movement.

Keywords: orthodontic treatment, tooth movement, stereovision system, long-term tracking

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Authors: Kazumasa Kawasaki, Isamu Tsuji, Hiroshi Gunbara

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A face gear drive is actually composed of a spur or helical pinion that is in mesh with a face gear and transfers power and motion between intersecting or skew axes. Due to the peculiarity of the face gear drive in shunt and confluence drive, it shows potential advantages in the application in the helicopter transmission. The advantages of such applications are the possibility of the split of the torque that appears to be significant where a pinion drives two face gears to provide an accurate division of power and motion. This mechanism greatly reduces the weight and cost compared to conventional design. Therefore, this has been led to revived interest and the face gear drive has been utilized in substitution for bevel and hypoid gears in limited cases. The face gear drive with a spur or a helical pinion is newly designed in order to determine an effective meshing area under the design parameters and specific design dimensions. The face gear has two unique dimensions which control the face width of the tooth, and the outside and inside diameters of the face gear. On the other hand, it is necessary to modify the tooth surfaces of face gear drive in order to avoid the influences of alignment errors on the tooth contact patterns in practical use. In this case, the pinion tooth surfaces are usually modified in the conventional method. However, it is hard to control the tooth contact pattern intentionally and adjust the position of the pinion axis in meshing of the gear pair. Therefore, a method of the modification of the tooth surfaces of the face gear is proposed. Moreover, based on tooth contact analysis, the tooth contact pattern and transmission errors of the designed face gear drive are analyzed, and the influences of alignment errors on the tooth contact patterns and transmission errors are investigated. These results showed that the tooth contact patterns and transmission errors were controllable and the face gear drive which is insensitive to alignment errors can be obtained.

Keywords: alignment error, face gear, gear design, helicopter transmission, tooth contact analysis

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Authors: Azin Zargham, Gholamreza Rouhi, Allahyar Geramy

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One of the most prevalent types of alveolar bone loss is horizontal bone loss (HBL) in which the bone height around teeth is reduced homogenously. In the presence of HBL the magnitudes of forces during orthodontic treatment should be altered according to the degree of HBL, in a way that without further bone loss, desired tooth movement can be obtained. In order to investigate the appropriate orthodontic force system in the presence of HBL, a three-dimensional numerical model capable of the simulation of orthodontic tooth movement was developed. The main goal of this research was to evaluate the effect of different degrees of HBL on a long-term orthodontic tooth movement. Moreover, the effect of different force magnitudes on orthodontic tooth movement in the presence of HBL was studied. Five three-dimensional finite element models of a maxillary lateral incisor with 0 mm, 1.5 mm, 3 mm, 4.5 mm and 6 mm of HBL were constructed. The long-term orthodontic tooth tipping movements were attained during a 4-weeks period in an iterative process through the external remodeling of the alveolar bone based on strains in periodontal ligament as the bone remodeling mechanical stimulus. To obtain long-term orthodontic tooth movement in each iteration, first the strains in periodontal ligament under a 1-N tipping force were calculated using finite element analysis. Then, bone remodeling and the subsequent tooth movement were computed in a post-processing software using a custom written program. Incisal edge, cervical, and apical area displacement in the models with different alveolar bone heights (0, 1.5, 3, 4.5, 6 mm bone loss) in response to a 1-N tipping force were calculated. Maximum tooth displacement was found to be 2.65 mm at the top of the crown of the model with a 6 mm bone loss. Minimum tooth displacement was 0.45 mm at the cervical level of the model with a normal bone support. Tooth tipping degrees of models in response to different tipping force magnitudes were also calculated for models with different degrees of HBL. Degrees of tipping tooth movement increased as force level was increased. This increase was more prominent in the models with smaller degrees of HBL. By using finite element method and bone remodeling theories, this study indicated that in the presence of HBL, under the same load, long-term orthodontic tooth movement will increase. The simulation also revealed that even though tooth movement increases with increasing the force, this increase was only prominent in the models with smaller degrees of HBL, and tooth models with greater degrees of HBL will be less affected by the magnitude of an orthodontic force. Based on our results, the applied force magnitude must be reduced in proportion of degree of HBL.

Keywords: bone remodeling, finite element method, horizontal bone loss, orthodontic tooth movement.

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Authors: Yanuarti Retnaningrum, Cendrawasih A. Farmasyanti, Kuswahyuning

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Orthodontists find challenges in treating patients who have cases of macroglossia and multiple tooth agenesis because difficulties in determining the causes, formulating a diagnosis and the potential for relapse after treatment. Definition of macroglossia is a tongue enlargement due to muscle hypertrophy, tumor or an endocrine disturbance. Macroglossia may cause many problems such as anterior proclination of upper and lower incisors, development of general diastema and anterior and/ or posterior open bite. Treatment for such patients with multiple tooth agenesis and macroglossia can be complex and must consider orthodontic and/or surgical interventions. This article discusses an orthodontic non surgical approach to a patient with a general diastema in both maxilla and mandible associated with multiple tooth agenesis and macroglossia. Fixed orthodontic therapy with straightwire appliance was used for space closure in anterior region of maxilla and mandible, also to create a space suitable for future prosthetic restoration. After 12 months treatment, stable and functional occlusal relationships was achieved, although still have edentulous area in both maxilla and mandible. At the end of the orthodontic treatment was obtained with correct overbite and overjet values. After removal of the brackets, a maxillary and mandibular removable retainer combine with artificial tooth were placed for retention.

Keywords: general diastema, macroglossia, space closure, tooth agenesis

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Authors: Jake Hindmarch, Edward Farley, Norman Eizenberg, Mark Midwinter

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There is a need to bring the anatomical knowledge of medical students up to the standards required by surgical specialties. Contention exists amongst anatomists, clinicians, and surgeons about the standard of anatomical knowledge medical students need. The aim of this study was to explore the standards which the Royal Australasian College of Surgeons are applying knowledge of anatomy. Furthermore, to align medical school teaching to what the surgical profession requires from graduates.: The 2018 volume of the ANZ Journal of Surgery was narrowed down to 254 articles by applying the search term “Anatomy”. The main topic was then extracted from each paper. The content of the paper was assessed for ‘novel description’ or ‘application’ of anatomical knowledge’ and classified accordingly. The majority of papers with an anatomical focus was from the general surgery specialty, which focused on surgical techniques, outcomes and management. Vascular surgery had the highest percentage of papers with a novel description and application of anatomy. Cardiothoracic and paediatric surgery had no papers with a novel description of anatomy. Finally, a novel application of anatomy was the main focus of each speciality. Firstly, a high proportion of novel applications and descriptions of anatomy are in general surgery. Secondly, vascular surgery had the largest proportion of novel application and description of anatomy, namely due to the rise of therapeutic imaging and endovascular techniques. Finally, all disciplines demonstrated a trend towards having a higher proportion of novel application of anatomical knowledge

Keywords: anatomical knowledge, anatomy, surgery, novel anatomy

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Authors: Suhayla Reda Al-Banai

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Problem Statement: Tooth whitening was used for over one hundred and fifty year. The question concerning the whiteness of teeth is a complex one since tooth whiteness will vary from individual to individual, dependent on age and culture, etc. Tooth whitening following treatment may be dependent on the type of whitening system used to whiten the teeth. There are a few side-effects to the process, and these include tooth sensitivity and gingival irritation. Some individuals may experience no pain or sensitivity following the procedure. Purpose: To systematically review the available published literature until 31st December 2021 to identify all relevant studies for inclusion and to determine whether there was any evidence demonstrating that the application of whitening procedures resulted in the tooth sensitivity. Aim: Systematically review the available published works of literature to identify all relevant studies for inclusion and to determine any evidence demonstrating that application of 10% & 15% carbamide peroxide in tooth whitening procedures resulted in tooth sensitivity. Material and Methods: Following a review of 70 relevant papers from searching both electronic databases (OVID MEDLINE and PUBMED) and hand searching of relevant written journals, 49 studies were identified, 42 papers were subsequently excluded, and 7 studies were finally accepted for inclusion. The extraction of data for inclusion was conducted by two reviewers. The main outcome measures were the methodology and assessment used by investigators to evaluate tooth sensitivity in tooth whitening studies. Results: The reported evaluation of tooth sensitivity during tooth whitening procedures was based on the subjective response of subjects rather than a recognized methodology for evaluating. One of the problems in evaluating was the lack of homogeneity in study design. Seven studies were included. The studies included essential features namely: randomized group, placebo controls, doubleblind and single-blind. Drop-out was obtained from two of included studies. Three of the included studies reported sensitivity at the baseline visit. Two of the included studies mentioned the exclusion criteria Conclusions: The results were inconclusive due to: Limited number of included studies, the study methodology, and evaluation of DS reported. Tooth whitening procedures adversely affect both hard and soft tissues in the oral cavity. Sideeffects are mild and transient in nature. Whitening solutions with greater than 10% carbamide peroxide causes more tooth sensitivity. Studies using nightguard vital bleaching with 10% carbamide peroxide reported two side effects tooth sensitivity and gingival irritation, although tooth sensitivity was more prevalent than gingival irritation

Keywords: dentine, sensitivity, bleaching, carbamide peroxde

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Authors: A. H. Elkholy, A. H. Falah

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A new approach has been developed to estimate the load share and stress distribution of worm gear sets. The approach is based upon considering the instantaneous tooth meshing stiffness where the worm gear drive was modelled as a series of spur gear slices, and each slice was analyzed separately using the well established formulae of spur gears. By combining the results obtained for all slices, the entire envolute worm gear set loading and stressing was obtained. The geometric modelling method presented, allows tooth elastic deformation and tooth root stresses of worm gear drives under different load conditions to be investigated. On the basis of the method introduced in this study, the instantaneous meshing stiffness and load share were obtained. In comparison with existing methods, this approach has both good analysis accuracy and less computing time.

Keywords: gear, load/stress distribution, worm, wheel, tooth stiffness, contact line

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Authors: Mateusz Hermyt, Pawel Kaczmarek, Weronika Rupik

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The egg tooth is a crucial structure during hatching of lizards and snakes. In contrast to birds, turtles, crocodiles, and monotremes, egg tooth of squamate reptiles is a true tooth sharing common features of structure and development with all the other teeth of vertebrates. The egg tooth; however, due to its function, exhibits structural differences in relation to regular teeth. External morphology seems to be important in the context of phylogenetic relationships within Squamata but up to date, there is scarce information concerning structure and development of the egg tooth at the submicroscopical level. In presented studies detailed analysis of the egg tooth development in grass snake has been performed with the usage of light (including fluorescent), transmission and scanning electron microscopy. Grass snake embryo’s heads have been used in our studies. Grass snake is common snake species occurring in most of Europe including Poland. The grass snake is characterized by the presence of single unpaired egg tooth (as in most squamates) in contrast to geckos and dibamids possessing paired egg teeth. Studies show changes occurring on the external morphology, tissue and cellular levels of differentiating egg tooth. The egg tooth during its development changes its curvature. Initially, faces directly downward and in the course of its differentiation, it gradually changes to rostro-ventral orientation. Additionally, it forms conical dentinal protrusions on the sides. Histological analysis showed that egg tooth development occurs in similar steps in relation to regular teeth. It undergoes initiation, bud, cap and bell morphological stages. Analyses focused on describing morphological changes in hard tissues (mainly dentin and predentin) of egg tooth and in cells which enamel organ consists of. It included: outer enamel epithelium, stratum intermedium, inner enamel epithelium, odontoblasts, and cells of dental pulp. All specimens used in the study were captured according to the Polish regulations concerning the protection of wild species. Permission was granted by the Local Ethics Commission in Katowice (41/2010; 87/2015) and the Regional Directorate for Environmental Protection in Katowice (WPN.6401.257.2015.DC).

Keywords: hatching, organogenesis, reptile, Squamata

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Authors: Siti Nurma Hanim Hadie, Asma’ Hassan, Zul Izhar Ismail, Ahmad Fuad Abdul Rahim, Mohd. Zarawi Mat Nor, Hairul Nizam Ismail

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Anatomy is a medical subject, which contributes to high cognitive load during learning. Despite its complexity, anatomy remains as the most important basic sciences subject with high clinical relevancy. Although anatomy knowledge is required for safe practice, many medical students graduated without having sufficient knowledge. In fact, anatomy knowledge among the medical graduates was reported to be declining and this had led to various medico-legal problems. Applying cognitive load theory (CLT) in anatomy teaching particularly lecture would be able to address this issue since anatomy information is often perceived as cognitively challenging material. CLT identifies three types of loads which are intrinsic, extraneous and germane loads, which combine to form the total cognitive load. CLT describe that learning can only occur when the total cognitive load does not exceed human working memory capacity. Hence, managing these three types of loads with the aim of optimizing the working memory capacity would be beneficial to the students in learning anatomy and retaining the knowledge for future application.

Keywords: cognitive load theory, intrinsic load, extraneous load, germane load

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Authors: K. Zhumadilov, P. Kazymbet, A. Ivannikov, M. Bakhtin, A. Akylbekov, K. Kadyrzhanov, A. Morzabayev, M. Hoshi

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The aim of the study is to evaluate the possible excess of dose received by uranium processing plant workers. The possible excess of dose of workers was evaluated with comparison with population pool (Stepnogorsk) and control pool (Astana city). The measured teeth samples were extracted according to medical indications. In total, twenty-seven tooth enamel samples were analyzed from the residents of Stepnogorsk city (180 km from Astana city, Kazakhstan). About 6 tooth samples were collected from the workers of uranium processing plant. The results of tooth enamel dose estimation show us small influence of working conditions to workers, the maximum excess dose is less than 100 mGy. This is pilot study of EPR dose estimation and for a final conclusion additional sample is required.

Keywords: EPR dose, workers, uranium mines, tooth samples

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Authors: Nasir Mustafa

Abstract:

One of the prerequisites required for an efficient diagnosis in a medical practice is to have a strong command of both functional and clinical anatomy. In this study, we introduce a new collaborative approach to the effective teaching of the knee and hip joints. In the present teaching model, anatomists, orthopedists and physical therapists present the anatomy of the hip and knee joints in small groups. Courses for the hip and knee joints were scheduled during the early stages of the medical curriculum. Students of nursing and physical therapy were grouped together to sensitize to the importance of a collaborative effort. The study results clearly demonstrate that nursing students and physical therapy students appreciated this teaching approach. The collaborative approach further proved to be a suitable method to teach both functional and clinical anatomy of the hip and knee joints. Aside from this training, a collaborative approach between medical students and physical therapy students was also successful for a healthcare organization.

Keywords: hip and knee joint anatomy, collaborative, Anatomy teaching, Nursing students, Physiotherapy students

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Authors: Abdulsalam I. Rafida, Abdulhmid M. Alkout, Abdultif M. Alroba

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This study investigates the heavy metal content in the saliva of persons with amalgam tooth fillings. For this purpose, samples of saliva have been collected based on two factors i.e. the number of amalgam fillings in the mouth (one, two or three fillings), and the time factor i.e. the time since the fillings have been in place (less than a year and more than a year). Samples of saliva have also been collected from persons with no amalgam tooth fillings for control. The samples that have been collected so far, have been examined for the basic heavy metal content featuring amalgam, which include mercury (Hg) and silver (Ag). However, all the above mentioned elements have been detected in the samples of saliva of the persons with amalgam tooth fillings, though with varying amounts depending on the number of fillings. Thus, for persons with only one filling the average quantities were found to be 0.00061 ppm and 0.033 ppm for Hg and Ag respectively. On the other hand for persons with two fillings the average quantities were found to be 0.0012 ppm and 0.029 ppm for each of the two elements respectively. However, in order to understand the chemical reactions associated with amalgam tooth fillings in the mouth, the material have been treated outside the mouth using some nutrient media. Those media included drinking water, fizzy drinks and hot tea. All three media have been found to contain the three elements after amalgam treatment. Yet, the fizzy drink medium was found to contain the highest levels of those elements.

Keywords: amalgam, mercury, silver, fizzy drinks, media

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Authors: Alitajer Saeed, Negintaji Farshad

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This study has been examined the relationship between anatomical components of mosques and place attachment of people to anatomies of mosques with the approach of attending to Islamic wisdom. To this end, this article by reviewing the theoretical and empirical literature of mosques' anatomy and the role of anatomy on the architectural design of Iranian mosques by examining the quantitative and qualitative indicators and in order to understand and identify the anatomy of mosques, components such as: entrance, portico, minarets, domes, bedchamber and pool have been investigated. For this purpose, SPSS software has been used. Research is related to field and is of descriptive, analytical and inferential type and quantitative and qualitative indicators have been examined. Statistical analysis obtained from the questionnaire indicates that there is a significant relationship between the anatomical components of architecture and place attachment of the participants. By understanding and identifying the anatomy of mosques and appropriate planning to use the anatomy in Islamic architecture and considering it as an eminent indicators of designing, it can present great Iranian architecture.

Keywords: Islamic wisdom, Islamic architecture, mosque anatomy place attachment, Islamic art

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Authors: Mamatha Hosapatna, Anne D. Souza, Antony Sylvan Dsouza, Vrinda Hari Ankolekar

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Our study intends to know the effect of the overall teaching program of Anatomy on a students learning. The advancement of various teaching methodologies in the present era has led to progressive changes in education. A student should be able to correlate well between the theory and practical knowledge attained even in the early years of their education in medicine and should be able to implement the same in patient care. The present study therefore aims to assess the impact the current anatomy teaching program has on a students learning and to what extent is it successful in making the learning program effective. Specific objectives of our study to assess the impact of overall teaching program of Anatomy in a students’ learning. Description of process proposed: A questionnaire will be constructed and the students will be asked to put forth their views regarding the Anatomy teaching program and its method of assessment. Suggestions, if any will also be encouraged to be put forth. Type of study is cross sectional observations. Target population is the first year MBBS students and sample size is 250. Assessment plan is to obtaining students responses using questionnaire. Calculating percentages of the responses obtained. Tabulation of the results will be done.

Keywords: anatomy, observational study questionnaire, observational study, M.B.B.S students

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Authors: Neeraj Malhotra, Ramya Shenoy

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Objective: To assess the effect of clinical parameters (bonding agent, preparation design & storage media) on the strength of reattached anterior tooth fragment. Methodology: This is a systematic review and meta-analysis for articles referred from MEDLINE, PUBMED, and GOOGLE SCHOLAR. The articles on tooth reattachment and clinical factors affecting fracture strength/bond strength/fracture resistance of the reattached tooth fragment in anterior teeth and published in English from 1999 to 2016 were included for final review. Results: Out of 120 shortlisted articles, 28 articles were included for the systematic review and meta-analysis based on 3 clinical parameters i.e. bonding agent, tooth preparation design & storage media. Forest plot & funnel plots were generated based on individual clinical parameter and their effect on strength of reattached anterior tooth fragment. Results based on analysis suggest combination of both conclusive evidence favoring the experimental group as well as in-conclusive evidence for individual parameter. Conclusion: There is limited evidence as there are fewer articles supporting each parameter in human teeth. Bonding agent had showed better outcome in selected studies.

Keywords: bonding agent, bond strength, fracture strength, preparation design, reattachment, storage media

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Authors: R. Sutjiati, Rubianto, I. B. Narmada, I. K. Sudiana, R. P. Rahayu

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The prevalence of post-treatment relapse in orthodontics in the community is high enough; therefore, relapses in orthodontic treatment must be prevented well. The aim of this study is to experimentally test the inhibition of relapse of orthodontics tooth movement in NaF of expression TGF-β1, Runx2, alkaline phosphatase (ALP) and microscopic of woven bone. The research method used was experimental laboratory research involving 30 rats, which were divided into three groups. Group A: rats were not given orthodontic tooth movement and without NaF. Group B: rats were given orthodontic tooth movement and without 11.5 ppm by topical application. Group C: rats were given orthodontic tooth movement and 11.75 ppm by topical application. Orthodontic tooth movement was conducted by applying ligature wires of 0.02 mm in diameter on the molar-1 (M-1) of left permanent maxilla and left insisivus of maxilla. Immunohistochemical examination was conducted to calculate the number of osteoblast to determine TGF β1, Runx2, ALP and haematoxylin to determine woven bone on day 7 and day 14. Results: It was shown that administrations of Natrium Fluoride topical application proved effective to increase the expression of TGF-β1, Runx2, ALP and to increase woven bone in the tension area greater than administration without natrium fluoride topical application (p < 0.05), except the expression of ALP on day 7 and day 14 which was significant. The results of the study show that NaF significantly increases the expressions of TGF-β1, Runx2, ALP and woven bone. The expression of the variables enhanced on day 7 compared on that on day 14, except ALP. Thus, it can be said that the acceleration of woven bone occurs on day 7.

Keywords: TGF-β1, Runx2, ALP, woven bone, natrium fluoride

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Authors: Fatma Mohamed Magdy Badr El Dine, Amr Mohamed Abd Allah

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Introduction: Age estimation of individuals is one of the crucial steps in forensic practice. Different traditional methods rely on the length of the diaphysis of long bones of limbs, epiphyseal-diaphyseal union, fusion of the primary ossification centers as well as dental eruption. However, there is a growing need for the development of precise and reliable methods to estimate age, especially in cases where dismembered corpses, burnt bodies, purified or fragmented parts are recovered. Teeth are the hardest and indestructible structure in the human body. In recent years, assessment of pulp/tooth area ratio, as an indirect quantification of secondary dentine deposition has received a considerable attention. However, scanty work has been done in Egypt in terms of applicability of pulp/tooth ratio for age estimation. Aim of the Work: The present work was designed to assess the Cameriere’s method for age estimation from pulp/tooth ratio of maxillary canines, central and lateral incisors among a sample from Egyptian population. In addition, to formulate regression equations to be used as population-based standards for age determination. Material and Methods: The present study was conducted on 270 peri-apical X-rays of maxillary canines, central and lateral incisors (collected from 131 males and 139 females aged between 19 and 52 years). The pulp and tooth areas were measured using the Adobe Photoshop software program and the pulp/tooth area ratio was computed. Linear regression equations were determined separately for canines, central and lateral incisors. Results: A significant correlation was recorded between the pulp/tooth area ratio and the chronological age. The linear regression analysis revealed a coefficient of determination (R² = 0.824 for canine, 0.588 for central incisor and 0.737 for lateral incisor teeth). Three regression equations were derived. Conclusion: As a conclusion, the pulp/tooth ratio is a useful technique for estimating age among Egyptians. Additionally, the regression equation derived from canines gave better result than the incisors.

Keywords: age determination, canines, central incisors, Egypt, lateral incisors, pulp/tooth ratio

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Authors: Ahmed Elkholy

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Most power transmission cases use gearing in general, and worm gearing, in particular for energy utilization. Therefore, designing gears for minimum weight and maximum power transmission is the main target of this study. In this regard, a new approach has been developed to estimate the load share and stress distribution of worm gear sets. The approach is based upon considering the instantaneous tooth meshing stiffness where the worm gear drive was modelled as a series of spur gear slices, and each slice was analyzed separately using a well-established criteria. By combining the results obtained for all slices, the entire worm gear set loading and stressing was determined. The geometric modelling method presented, allows tooth elastic deformation and tooth root stresses of worm gear drives under different load conditions to be investigated. On the basis of the method introduced in this study, the instantaneous meshing stiffness and load share were obtained. In comparison with existing methods, this approach has both good analytical accuracy and less computing time.

Keywords: gear, load/stress distribution, worm, wheel, tooth stiffness, contact line

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Authors: Vlado Ostovic

Abstract:

An electric machine topology characterized by single tooth winding in both stator and rotor is presented. The proposed machine is capable of operating as a direct drive double fed wind generator (DDDF, D3F) because it requires no gearbox and only a reduced-size converter. A wind turbine drive built around a D3F generator is cheaper to manufacture, requires less maintenance, and has a higher energy yield than its conventional counterparts. The single tooth wound generator of a D3F turbine has superb volume utilization and lower stator I2R losses due to its extremely short-end windings. Both stator and rotor of a D3F generator can be manufactured in segments, which simplifies its assembly and transportation to the site, and makes production cheaper.

Keywords: direct drive, double fed generator, gearbox, permanent magnet generators, single tooth winding, wind power

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Authors: Pakize Neslihan Taslı, Alev Cumbul, Gul Merve Yalcın, Fikrettin Sahin

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A key experimental trial in the regeneration of large oral and craniofacial defects is the neogenesis of osseous and ligamentous interfacial structures. Currently, oral regenerative medicine strategies are unpredictable for repair of tooth supporting tissues destroyed as a consequence of trauma, chronic infection or surgical resection. A different approach combining the gel-casting method with Hydroxy Apatite HA-based scaffold and different cell lineages as a hybrid system leads to successively mimic the early stage of tooth development, in vitro. HA is widely accepted as a bioactive material for guided bone and tooth regeneration. In this study, it was reported that, HA porous scaffold preparation, characterization and evaluation of structural and chemical properties. HA is the main factor that exists in tooth and it is in harmony with structural, biological, and mechanical characteristics. Here, this study shows mimicking immature tooth at the late bell stage design and construction of HA scaffolds for cell transplantation of human Adipose Stem Cells (hASCs), human Bone Marrow Stem Cells (hBMSCs) and Gingival Epitelial cells for the formation of human tooth dentin-pulp-enamel complexes in vitro. Scaffold characterization was demonstrated by SEM, FTIR and pore size and density measurements. The biological contraction of dental tissues against each other was demonstrated by mRNA gene expressions, histopatologic observations and protein release profile by ELISA tecnique. The tooth shaped constructs with a pore size ranging from 150 to 300 µm arranged by gathering right amounts of materials provide interconnected macro-porous structure. The newly formed tissue like structures that grow and integrate within the HA designed constructs forming tooth cementum like tissue, pulp and bone structures. These findings are important as they emphasize the potential biological effect of the hybrid scaffold system. In conclusion, this in vitro study clearly demonstrates that designed 3D scaffolds shaped as a immature tooth at the late bell stage were essential to form enamel-dentin-pulp interfaces with an appropriate cell and biodegradable material combination. The biomimetic architecture achieved here is providing a promising platform for dental tissue engineering.

Keywords: tooth regeneration, tissue engineering, adipose stem cells, hydroxyapatite tooth engineering, porous scaffold

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Authors: L. Sun, T. Hargreaves, Z. Ahmad

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Newly-qualified Foundation Year 1 doctors in the United Kingdom are frequently expected to perform practical skills involving the upper limb in clinical practice (for example, venipuncture, cannulation, and blood gas sampling). However, a move towards systems-based undergraduate medical education in the United Kingdom often precludes or limits dedicated time to anatomy teaching with cadavers or prosections, favouring only applied anatomy in the context of pathology. The authors hypothesised that detailed anatomical knowledge may consequently be adversely affected, particularly with respect to long-term retention. A simple picture quiz and accompanying questionnaire testing the identification of 7 upper limb surface landmarks was distributed to a total of 98 final year medical students from two universities - one with a systems-based curriculum, and one with a dedicated longitudinal dissection-based anatomy module in the first year of study. Students with access to dissection and prosection-based anatomy teaching performed more strongly, with a significantly higher rate of correct identification of all but one of the landmarks. Furthermore, it was notable that none of the students who had previously undertaken a systems-based course scored full marks, compared with 20% of those who had participated in the more dedicated anatomy course. This data suggests that a traditional, dissection-based approach to undergraduate anatomy teaching is superior to modern system-based curricula, in terms of aiding long-term retention of anatomical knowledge pertinent to newly-qualified doctors. The authors express concern that this deficit in proficiency could be detrimental to patient care in clinical practice, and propose that, where dissection-led anatomy teaching is not available, further anatomy revision modules are implemented throughout undergraduate education to aid knowledge retention and support clinical excellence.

Keywords: dissection, education, surface anatomy, upper limb

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Authors: Tarek Abdelkader, Suresh Selvaraj, Prasad Iyer, Yong Mun Hin, Hajmath Begum, P. Gopalakrishnakone

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Nowadays, more and more educational institutes, as well as students, rely on 3D anatomy programs as an important tool that helps students correlate the actual locations of anatomical structures in a 3D dimension. Lately, virtual reality (VR) is gaining more favor from the younger generations due to its higher interactive mode. As a result, using virtual reality as a gamified learning platform for anatomy became the current goal. We present a model where a Virtual Human Anatomy Program (VHAP) was developed to assist with the anatomy learning experience of students. The anatomy module has been built, mostly, from real patient CT scans. Segmentation and surface rendering were used to create the 3D model by direct segmentation of CT scans for each organ individually and exporting that model as a 3D file. After acquiring the 3D files for all needed organs, all the files were introduced into a Virtual Reality environment as a complete body anatomy model. In this ongoing experiment, students from different Allied Health orientations are testing the VHAP. Specifically, the cardiovascular system has been selected as the focus system of study since all of our students finished learning about it in the 1st trimester. The initial results suggest that the VHAP system is adding value to the learning process of our students, encouraging them to get more involved and to ask more questions. Involved students comments show that they are excited about the VHAP system with comments about its interactivity as well as the ability to use it solo as a self-learning aid in combination with the lectures. Some students also experienced minor side effects like dizziness.

Keywords: 3D construction, health sciences, teaching pedagogy, virtual reality

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Authors: Amin Akbari, Dongcai Wang, Huiru Li, Xiaoping Du, Jie Chen

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The effect of vibrational force (VF) on accelerating orthodontic tooth movement depends on the level of delivered stimulation to the tooth in terms of peak load (PL), which requires contacts between the tooth and the VF device. A personalized device ensures the contacts, but the resulting PL distribution on the teeth is unknown. Furthermore, it is unclear whether the PL on particular teeth can be adjusted to the prescribed values. The objective of this study was to investigate the efficacy of apersonalized VF device in controlling the level of stimulation on two teeth, the mandibular canines and 2nd molars. A 3-D finite element (FE) model of human dentition, including teeth, PDL, and alveolar bone, was created from the cone beam computed tomography images of an anonymous subject. The VF was applied to the teeth through a VFdevice consisting of a mouthpiece with engraved tooth profile of the subject and a VF source that applied 0.3 N force with the frequency of 30 Hz. The dentition and mouthpiece were meshed using 10-node tetrahedral elements. Interface elements were created at the interfaces between the teeth and the mouthpiece. The upper and lower teeth bite on the mouthpiece to receive the vibration. The depth of engraved individual tooth profile could be adjusted, which was accomplished by adding a layer of material as an interference or removing a layer of material as a clearance to change the PL on the tooth. The interference increases the PL while the clearance decreases it. Fivemouthpiece design cases were simulated, which included a mouthpiece without interference/clearance; the mouthpieces with bilateral interferences on both mandibular canines and 2nd molars with magnitudes of 0.1, 0.15, and 0.2-mm, respectively; and mouthpiece with bilateral 0.3-mm clearances on the four teeth. Then, the force distributions on the entire dentition were compared corresponding to these adjustments. The PL distribution on the teeth is uneven when there is no interference or clearance. Among all teeth, the anterior segment receives the highest level of PL. Adding 0.1, 0.15, and 0.2-mm interferences to the canines and 2nd molars bilaterally leads to increase of the PL on the canines by 10, 62, and 73 percent and on the 2nd molar by 14, 55, and 87 percent, respectively. Adding clearances to the canines and 2nd molars by removing the contactsbetween these teeth and the mouthpiece results in zero PL on them. Moreover, introducing interference to mandibular canines and 2nd molarsredistributes the PL on the entireteeth. The share of the PL on the anterior teeth are reduced. The use of the personalized mouthpiece ensures contactsof the teeth to the mouthpiece so that all teeth can be stimulated. However, the PL distribution is uneven. Adding interference between a tooth and the mouthpiece increases the PL while introducing clearance decreases the PL. As a result, the PL is redistributed. This study confirms that the level of VF stimulation on the individual tooth can be adjusted to a prescribed value.

Keywords: finite element method, orthodontic treatment, stress analysis, tooth movement, vibrational force

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Authors: Regina Tedjasulaksana, Maria Martina Nahak, A. A. Gede Agung, Ni Made Widhiasti

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Strategic effort to realize the empowerment of community in school is through the peer group approach so that it needs to choose the students who are trained as the’ little dentist’ in order to have the cognitive and skills to participate in the school dental health effort (UKGS) program, such as providing oral health education to the other students. Aim: To assessed the effectiveness of peer group approach to enhance the oral health knowledge level of schoolchildren at primary school in Klungkung, Bali. Methods: Experimental study using the pre-post test without control group design. The differences of knowledge levels, tooth brushing behavior and oral hygiene status (using PHP-M index) of 10 students before and after trained as the little dentists were analyzed using paired t-test. The correlations between knowledge level and tooth brushing behavior and correlations between tooth brushing behavior and oral hygiene before and after trained as the little dentists were analyzed using Spearman. Furthermore, the trained little dentists provide oral health education to 102 students of grade 1 to 5 at their school once a week for 3 months. The students’ knowledge level scores of each grade were taken every 21 days as many as three times The difference of it was analyzed using Repeated Measured. Result: The mean scores among all little dentists before and after training for each of knowledge level were each 63.05 + 5.62 and 85.00 + 7.81, tooth brushing behavior were each 31.00 + 14.49 and 100.00 + 0.00 and oral hygiene status using PHP-M index were each 32.80 + 10.17 and 11.40 + 8.01. The knowledge level, tooth brushing behavior and oral hygiene status of 10 students before and after trained as the little dentists were different significantly (p<0.05). Before and after trained as the little dentists it showed that significant correlations between knowledge level with tooth brushing behavior (p<0.05) and significant correlations between tooth brushing behavior and oral hygiene (p<0.05). The mean scores of knowledge level among all students before (pre-test) and after (post-test (1),(2),(3)) getting oral health education from little dentists for each, of grade 1 were 40.00 + 17.97; 67.85 + 18.88; 81.72 +26.48 and 70.00 + 22.87, grade 2 were 40.00 + 17.97; 67.85 + 18.88; 81.72 + 26.48 and 70.00 + 22.87, grade 3 were 65.83 + 23.94; 72.50 + 26.08; 80.41 + 24.93 and 83.75 + 19.74, grade 4 were 88.57 + 12.92; 90.71 + 9.97; 92.85 + 10.69 and 93.57 + 6.33 and grade 5 were 86.66 + 13.40; 93.33 + 9.16; 94.16 + 10.17 and 98.33 + 4.81. The students’ knowledge level of grade 1,2 and 3 before and after getting oral health education from little dentists showed significant different (p<0.05), meanwhile there was no significant different on grade 4 and 5 (p<0.05) although mean scores showed an increase. Conclusion: Peer group approach can be used to enhance the oral health knowledge level of schoolchildren at primary school in Klungkung, Bali.

Keywords: small dentists, oral health, peer group approach, school children

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Authors: Lelika Lazarus, Reshma Sookrajh, Kapil S. Satyapal

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Reflecting on teaching is commonly cited as a fundamental practice for personal and professional development. Educational research into the scholarship of teaching and learning anatomy includes engaging in discipline specific literature on teaching, reflecting on individual teaching methods and communicating these findings to peers. The aim of this paper is to formally assess the opinions of senior anatomy instructors regarding the state of anatomical knowledge at their respective institutions. The context of the paper derives from ongoing debates about the perceived decline in standards of anatomical knowledge of medical students and postgraduate learners. An open ended questionnaire was devised consisting of eight direct questions seeking opinions on anatomy teaching, knowledge, and potential educational developments and general thoughts on the teaching of anatomy to medical students. These were distributed to senior anatomy Faculty (identified by the author by their affiliation with the Anatomical Society of Southern Africa) based at the eight national medical schools within the country. A number of key themes emerged. Most senior faculty felt that the standard of medical education at their respective institutions was ‘good.’. However, emphasis was also placed on the ‘quality of teaching’ incorporating clinical scenarios. There were also indications that staff are split into those that are keen to do research and those that are happy to provide teaching to medical students as their primary function. Several challenges were also highlighted such as time constraints within the medical curriculum, the lack of cadavers to reinforce knowledge and gain depth perception and lack of appropriately qualified staff. Recommendations included fostering partnerships with both clinicians and medical scientists into the anatomy curriculum thus improving teaching and research.

Keywords: anatomy, education, reflection, teaching

Procedia PDF Downloads 261

Authors: Najlaa Yousef Qusti, Steven J. Brookes, Paul A. Brunton

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Background: Tooth discoloration can be an aesthetic problem, and tooth whitening using carbamide peroxide bleaching agents are a popular treatment option. However, there are concerns about possible adverse effects such as demineralisation of the bleached enamel; however, the cause of this demineralisation is unclear. Introduction: Teeth can become stained or discoloured over time. Tooth whitening is an aesthetic solution for tooth discoloration. Bleaching solutions of 10% carbamide peroxide (CP) have become the standard agent used in dentist-prescribed and home-applied ’vital bleaching techniques’. These materials release hydrogen peroxide (H₂O₂), the active whitening agent. However, there is controversy in the literature regarding the effect of bleaching agents on enamel integrity and enamel mineral content. The purpose of this study was to establish if carbamide peroxide bleaching agents affect the acid solubility of enamel (i.e., make teeth more prone to demineralisation). Materials and Methods: Twelve human premolar teeth were sectioned longitudinally along the midline and varnished to leave the natural enamel surface exposed. The baseline behavior of each tooth half in relation to its demineralisation in acid was established by sequential exposure to 4 vials containing 1ml of 10mM acetic acid (1 minute/vial). This was followed by exposure to 10% CP for 8 hours. After washing in distilled water, the tooth half was sequentially exposed to 4 further vials containing acid to test if the acid susceptibility of the enamel had been affected. The corresponding tooth half acted as a control and was exposed to distilled water instead of CP. The mineral loss was determined by measuring [Ca²⁺] and [PO₄³⁻] released in each vial using a calcium ion-selective electrode and the phosphomolybdenum blue method, respectively. The effect of bleaching on the tooth surfaces was also examined using SEM. Results: Exposure to carbamide peroxide did not significantly alter the susceptibility of enamel to acid attack, and SEM of the enamel surface revealed a slight alteration in surface appearance. SEM images of the control enamel surface showed a flat enamel surface with some shallow pits, whereas the bleached enamel appeared with an increase in surface porosity and some areas of mild erosion. Conclusions: Exposure to H₂O₂ equivalent to 10% CP does not significantly increase subsequent acid susceptibility of enamel as determined by Ca²⁺ release from the enamel surface. The effects of bleaching on mineral loss were indistinguishable from distilled water in the experimental system used. However, some surface differences were observed by SEM. The phosphomolybdenum blue method for phosphate is compromised by peroxide bleaching agents due to their oxidising properties. However, the Ca²⁺ electrode is unaffected by oxidising agents and can be used to determine the mineral loss in the presence of peroxides.

Keywords: bleaching, carbamide peroxide, demineralisation, teeth whitening

Procedia PDF Downloads 99

Authors: Joanne Rieta Miranda

Abstract:

Learning anatomy and physiology among Deaf Non-Science major students is a challenge. They have this mindset that Anatomy and Physiology are difficult and very technical. In this study, nine (9) deaf students who are business majors were considered. Non-conventional teaching strategies and classroom activities were employed such as cooperative learning, virtual lab, Facebook live, big sky, blood typing, mind mapping, reflections, etc. Of all the activities; the deaf students ranked cooperative learning as the best learning activity. This is where they played doctors. They measured the pulse rate, heart rate and blood pressure of their partner classmate. In terms of mindset, 2 out of 9 students have a growth mindset with some fixed ideas while 7 have a fixed mindset with some growth ideas. All the students passed the course. Three out of nine students got a grade of 90% and above. The teacher was evaluated by the deaf students as very satisfactory with a mean score of 3.54. This means that the learner-centered practices in the classroom are manifested to a great extent.

Keywords: deaf students, learning anatomy and physiology, teaching strategies, learner-entered practices

Procedia PDF Downloads 201

Authors: Nor Hidayah Reduwan, Jira Chindasombatjaroen, Suchaya Pornprasersuk-Damrongsri, Sopee Pomsawat

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INTRODUCTION: Odontogenic keratocyst (OKC) remain as a controversial pathologic entity under the scrutiny of many researchers and maxillofacial surgeons alike. The high recurrence rate and relatively aggressive nature of this lesion demand a meticulous analysis of the radiographic characteristic of OKC leading to the formulation of an accurate diagnosis. OBJECTIVE: This study aims to determine the radiographic characteristic of odontogenic keratocyst (OKC) using conventional radiographs and cone beam computed tomography (CBCT) images. MATERIALS AND METHODS: Patients histopathologically diagnosed as OKC from 2003 to 2016 by Oral and Maxillofacial Pathology Department were retrospectively reviewed. Radiographs of these cases from the archives of the Department of Oral and Maxillofacial Radiology, Faculty of Dentistry Mahidol University were retrieved. Assessment of the location, shape, border, cortication, locularity, the relationship of lesion to embedded tooth, displacement of adjacent tooth, root resorption and bony expansion of the lesion were conducted. RESULTS: Radiographs of 91 patients (44 males, 47 females) with the mean age of 31 years old (10 to 84 years) were analyzed. Among all patients, 5 cases were syndromic patients. Hence, a total of 103 OKCs were studied. The most common location was at the ramus of mandible (32%) followed by posterior maxilla (29%). Most cases presented as a well-defined unilocular radiolucency with smooth and corticated border. The lesion was in associated with embedded tooth in 48 lesions (47%). Eighty five percent of embedded tooth are impacted 3rd molar. Thirty-seven percentage of embedded tooth were entirely encapsulated in the lesion. The lesion attached to the embedded tooth at the cementoenamel junction (CEJ) in 40% and extended to part of root in 23% of cases. Teeth displacement and root resorption were found in 29% and 6% of cases, respectively. Bony expansion in bucco-lingual dimension was seen in 63% of cases. CONCLUSION: OKCs were predominant in the posterior region of the mandible with radiographic features of a well-defined, unilocular radiolucency with smooth and corticated margin. The lesions might relate to an embedded tooth by surrounding an entire tooth, attached to the CEJ level or extending to part of root. Bony expansion could be found but teeth displacement and root resorption were not common. These features might help in giving the differential diagnosis.

Keywords: cone beam computed tomography, imaging dentistry, odontogenic keratocyst, radiographic features

Procedia PDF Downloads 104