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.

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Background: Antimicrobial photodynamic therapy (PDT) has been introduced as a potential option for peri-implantitis treatment. The aim of this study is to evaluate the antimicrobial effect of a novel technique involving a combination of 445 nm diode laser light with 0.1% riboflavin solution (used as a photosensitizing dye) as applied on a bacterial–fungal biofilm formed on implants and to compare the performance of this technique with that of the commonly used combination of 660 nm diode laser with 0.1% methylene blue dye. Methods: An in vitro study was conducted on 80 titanium dental implants contaminated with Staphylococcus aureus (SA) and Candida albicans (CA) species. The implants were randomly divided into four groups: negative control (NC), without surface treatment; positive control (PC), treated with a 0.2% chlorhexidine (CHX)-based solution; PDT1, 660 nm (EasyTip 320 µm, 200 mW, Q power = 100 mW, 124.34 W/cm2, 1240 J/cm2) with a 0.1% methylene blue dye; and PDT2, 445 nm (EasyTip 320 µm, 200 mW, Q power = 100 mW, 100 Hz, 124.34 W/cm2, 1.24 J/cm2) with a 0.1% riboflavin dye. Results: The PDT1 and PDT2 groups showed greater reduction of SA and CA in comparison to the NC group and no significant differences in comparison to the PC group. No statistically significant differences between the PDT1 and PDT2 groups were observed. Conclusions: A novel antimicrobial treatment involving a combination of 445 nm diode laser light with riboflavin solution showed efficiency in reducing SA and CA biofilm formation on dental implant surfaces comparable to those of the more commonly used PDT treatment consisting of 660 nm diode laser light with methylene blue dye or 0.2% CHX treatment.

<div class="WordSection1"><p><strong>Objective. </strong>To evaluate and compare the water sorption of three luting cements in three different solutions: distilled water and artificial saliva with different pH values (7.4 and 3.0). <strong>Materials and methods</strong>. Resin-modified glass-ionomer cement (GC Fuji Plus) and two resin cements (Multilink Automix and Variolink II) were used. A total of 45 specimens - 15 specimens (15x1 mm) for each cement were prepared according to ISO standard 4049:2009. The water sorptions of the cements were calculated by weighing the specimens before and after immersion and desiccation. <strong>Results. </strong>Nonparametric statistic methods were applied. GC Fuji Plus cement showed significantly higher values of water sorption in all three solutions of both resin cements (p&lt;0.009) and significantly higher values of sorption in artificial saliva pH 3.0. Multilink Automix showed significantly higher values of water sorption compared with Variolink II in artificial saliva pH 7.4, and higher values of sorption in this solution compared with pH value 3.0. <strong>Con- clusion. </strong>Water sorption values are mainly influenced by the proportion of hydrophilic matrix, the type and composition of filler, and the pH value of solutions.</p></div>

RESUMO ABSTRACTRadioterapia; Neoplasias de cabeça e pescoço; Efeitos de radiação; Cárie dentária.Radiotherapy; Head and neck neoplasms; Radiati on eff ects; Dental caries. Objecti ve: To determine the incidence of radiati on induced caries in conventi onally treated pati ents with head and neck cancer in Bosnian populati on. Method: A number of 30 pati ents with malignant diseases were included into this study, from the Clinic for Maxillofacial Surgery and Clinic for Otorhinolaryngology. All the pati ents were treated with radiotherapy in the region of head and neck, at the Insti tute for Oncology, Clinical Centre of University in Sarajevo. All thirty pati ents were examined in four ti me periods: before the radiati on, 3 weeks aft er commencing the radiati on, three months aft er commencing the radiati on and six months aft er commencing the radiati on. DESCRITORES KEYWORDS