Objective:The present study aims to investigate the influence of presence and shape of cervical lesions on biomechanical behavior of mandibular first premolar, subjected to two types of occlusal loading using three-dimensional (3D) finite element method (FEM).Materials and Methods:3D models of the mandibular premolar are created from a micro computed tomography X-ray image: model of sound mandibular premolar, model with the wedge-shaped cervical lesion (V lesion), and model with saucer-shaped cervical lesion (U lesion). By FEM, straining of the tooth tissues under functional and nonfunctional occlusal loading of 200 (N) is analyzed. For the analysis, the following software was used: CTAn program 1.10 and ANSYS Workbench (version 14.0). The results are presented in von Mises stress.Results:Values of calculated stress in all tooth structures are higher under nonfunctional occlusal loading, while the functional loading is resulted in homogeneous stress distribution. Nonfunctional load in the cervical area of sound tooth model as well as in the sub-superficial layer of the enamel resulted with a significant stress (over 50 [MPa]). The highest stress concentration on models with lesions is noticed on the apex of the V-shaped lesion, while stress in saucer U lesion is significantly lower and distributed over wider area.Conclusion:The type of the occlusal teeth loading has the biggest influence on cervical stress intensity. Geometric shape of the existing lesion is very important in the distribution of internal stress. Compared to the U-shaped lesions, V-shaped lesions show significantly higher stress concentrations under load. Exposure to stress would lead to its progression.
Introduction:An abfraction lesion is a type of a non-carious cervical lesion (NCCL) that represents a sharp defect on the cervical part of tooth, caused by occlusal biomechanical forces. The largest prevalence of the NCCL is found on the mandibular first premolar. The goal of the study is, by means of a numerical method – the finite element method (FEM), in an appropriate computer program, conduct a stress analysis of the mandibular premolar under various static loads, with a special reference to the biomechanics of cervical tooth region.Material and methods:A three-dimensional model of the mandibular premolar is gained from a µCT x-ray image. By using the FEM, straining of the enamel, dentin, peridontal ligament and alveolar bone under axial and paraxial forces of 200 [N] is analyzed. The following software were used in the analysis: CT images processing–CTAn program and FEM analysis–AnsysWorkbench 14.0.Results:According to results obtained through the FEM method, the calculated stress is higher with eccentric forces within all tested tooth tissue. The occlusal load leads to a significant stress in the cervical tooth area, especially in the sub-superficial layer of the enamel (over 50 MPa). The measured stress in the peridontal ligament is approximately three times higher under paraxial load with regard to the axial load, while stress calculated in the alveolar bone under paraxial load is almost ten times higher with regard to the axial load. The highest stress values were calculated in the cervical part of the alveoli, where bone resorption is most commonly seen.Conclusion:Action of occlusal forces, especially paraxial ones, leads to significant stress in the cervical part of tooth. The stress values in the cervical sub-superficial enamel layer are almost 5 times higher in relation to the superficial enamel, which additionally confirms complexity of biomechanical processes in the creation of abfraction lesions.
IntroductionIn Bosnia and Herzegovina, apart from domicile population, there is a certain number of displaced persons. Most of them are situated in the area of Canton Tuzla. These persons are generally at risk of and being watched for various diseases, including the disease of the orofacial area. Dental fear and anxiety (DFA) is also inevitably present in displaced persons, with higher prevalence compared with general population. Therefore, the aim was to evaluate the DFA presence and the most common reasons for dental fear and anxiety in displaced persons in our country.Patients and methods310 interviewed persons were included in this study, aged 35 to 44 years, from several cities of Canton Tuzla. They were divided in the group of displaced persons (n=153), and the group of domicile inhabitants (n=157). The study participants were interviewed about the DFA presence, as well as about the risk factors for DFA, which was subsequently evaluated by the Modified Corah's Dental Anxiety Scale.ResultsA high prevalence of DFA presence was determined in the total sample (38.71%), and particularly in the displaced persons group (57.52%). The results showed that displaced persons rarely visited dentists, mainly when it was necessary (odontalgia), with stronger reactions to factors that could cause DFA appearance.ConclusionDisplaced persons are regarded as one of the highest risk groups for prevalence of DFA. This could be mainly due to poor oral health status, rare dental office visits and the urgent need for dental treatment, which could lead to vicious circle of mutual strengthening between bad oral health and DFA appearance.
<p><strong>Objective.</strong> To evaluate the influence of gender on the mental index (MI) and the mandibular cortical index (MCI).</p><p><strong>Methods.</strong> In this study, there were 120 subjects (43 male and 77 female subjects), who had undergone a dental panoramic radiograph examination for the needs of diagnosis and future treatment planning. MI and MCI were determined by orthopantomograph.</p><p><strong>Results.</strong> There was a statistically significant difference in MI dependent on gender. Male patients demonstrated significantly higher values for MI than female patients (right: t=4.127; P=0.0001, left: t=3.110; P=0.002). No statistically significant difference was observed for MCI dependent on gender (right: χ²=2.36 P=0.308, left: χ²=3.85 P=0.146).</p><p><strong>Conclusion. </strong>MI is affected by gender, but MCI is not.</p>
Introduction: Dentists and generally dental personnel work under the risk of being infected by patients suffering from COVID-19, who are unaware that they are infected. The reason lies in the fact that during dental procedures, aerosol is formed with droplets that may contain the virus. Thus, it is extremely important that dental personnel complies with adequate protective measures and equipment during clinical work. The aim of this investigation was to evaluate the knowledge of COVID-19 and determine the amount of stress with dental personnel of the Faculty of Dentistry in Sarajevo, Bosnia and Herzegovina. Methods: Health care personnel of the Faculty of Dentistry with Clinics of the University in Sarajevo have been included in the research: teaching staff, clinical doctors, dental nurses and dental technicians. The research was conducted in April 2020. It was conducted by an anonymous survey that participants filled-in. Out of 157 distributed questionnaires in paper form, 134 participants responded. The questionnaire was divided into 3 parts: 1) personal data 2) knowledge of infection COVID-19 (diagnostic methods, transmission pathways, prevention measures); 3) the amount of stress (feelings and thoughts) during epidemic COVID-19 with personnel. Results: The largest number of participants (61.97%) consider that COVID-19 may be transmitted from infected to a healthy person by inhalation of droplets generated through coughing of an infected person and by direct contact with aerosol dispersed from the mouth of the infected patient during dental treatment. The largest number of participants, 80 of them (59.7%) consider that the method of nucleic acid test is used in diagnosing COVID-19. COVID – 19 had a significantly larger influence on females; they showed higher extent of concern for the claim „I hardly fall asleep because of thinking about it“, „I try not to talk on this topic“ and „In my mind appear pictures in relation to this.“ (p<0.05) Conclusion: Knowledge of COVID-19 and measures of protection of health care personnel at the Faculty of dentistry with Clinics in Sarajevo is satisfactory. The largest fear of participants was fear of unconsciously transmitting the infection on people close to them and that members of their families become infected with COVID-19.
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