Abstract Objective  This study investigated biomechanical behavior of custom post core made of six different materials on the tooth with and without the ferrule under different occlusal load. Materials and Methods  Three-dimensional models of mandibular first premolar, with and without ferrule, reconstructed from micro-computed tomography image are restored with different custom post core and zirconia crowns. By using the finite element analysis, von Mises stress shown in MPa was measured under simulated axial and oblique load of 200 [N]. To compare the stress distribution, six different custom post core materials were chosen: zirconia, Ni-Cr alloy, gold alloy, glass fiber-polyether ether ketone, polyether ether ketone, and carbon fiber-polyether ether ketone. Results  Custom post cores with a higher modulus of elasticity showed higher measured stress in the posts, but less stress in dentin. Measured stress in custom post core under oblique loading was approximately three times higher compared with axial loading. Stress in custom post core and in dentin under both types of loads was slightly higher in teeth without ferrule effect. Conclusion  The use of custom cast post cores made of different alloys is recommended in restoration of endodontically treated teeth, with extensive loss of tooth structure especially in teeth without ferrule effect.

Introduction: Stress among students is a growing problem. As emotional stress increases, the limbic structures and hypothalamus are stimulated, activating the gamma efferent system, which ultimately leads to an increase in muscle tone or additional muscle activity that can become repetitive behaviors such as bruxism. The aim of the study was to investigate the stress level that students are exposed to, to determine the difference between students in terms of gender, faculty, and year of study, and to evaluate the possible relationship between stress level and self-reported bruxism in college students during the pandemic COVID-19. Methods: In April 2022, a cross-sectional study was conducted on a sample of students from the Faculty of Dentistry and the Faculty of Pharmacy at the University of Sarajevo (BiH). The students answered a questionnaire consisting of two parts: The first part contained questions on basic personal data and data on self-reported bruxism and the second part contained questions on the perceived stress scale (PSS). Results: The study included 756 students from both faculties. Analysis of stress levels among students revealed higher stress levels. Female students were more likely to be under stress than male respondents. Students in the Faculty of Pharmacy were more likely to be stressed than students in the Faculty of Dentistry. At the Faculty of Pharmacy, there was no difference in stress levels between the different years of study, while at the Faculty of Dentistry, the individual score for PSS was highest among 1st-year students. A high prevalence (46.8%) of self-reported bruxism was found among students in both faculties. Conclusion: A slight positive correlation between self-reported bruxism and stress suggests that it is important to implement stress management strategies during academic education and to prevent bruxism and its consequences.

(1) Background: This study evaluates the effect of a conventional/low-voltage light-curing protocol (LV protocol) (10 s with 1340 mW/cm2) and high-voltage light-curing protocol (HV protocol) (3 s with 3440 mW/cm2) on the microhardness (MH) of dental resin-based composites (RBCs). Five resin composites were tested: conventional Evetric (EVT), Tetric Prime (TP), Tetric Evo Flow (TEF), bulk-fill Tetric Power Fill (PFL), and Tetric Power Flow (PFW). (2) Materials and Methods: Two tested composites (PFW and PFL) were designed for high-intensity light curing. The samples were made in the laboratory in specially designed cylindrical molds; diameter = 6 mm and height = 2 or 4 mm, depending on the type of composite. Initial MH was measured on the top and bottom surfaces of composite specimens 24 h after light curing using a digital microhardness tester (QNESS 60 M EVO, ATM Qness GmbH, Mammelzen, Germany). The correlation between the filler content (wt%, vol%) and the MH of the RBCs was tested. For the calculation of depth-dependent curing effectiveness, the bottom/top ratio for initial MH was used. (3) Conclusions: MH of RBCs is more dependent on material composition than on light-curing protocol. Filler wt% has a greater influence on MH values compared to filler vol%. The bottom/top ratio showed values over 80% for bulk composites, while for conventional sculptable composites, borderline or suboptimal values were measured for both curing protocols.

Abstract Objectives  The aim of the study was to analyze the occurrence of stress on teeth with abfraction lesions restored with six different restorative materials, and by introducing the tensile strength parameters to calculate the safety factor of the material under the load (ratio between the strength of the material and the maximum stress). Materials and Methods  Three-dimensional models of the mandibular premolar are created from a microcomputed tomography images. An abfraction lesion is modeled on the tooth. The stress of the dental tissues and six restorative materials under functional and nonfunctional occlusal loading of 200 (N) are analyzed by finite element method. Statistical Analysis  CTAn program 1.10 and ANSYS Workbench (version 14.0) were used for analysis. Results are presented in von Mises stress. Results  Oblique loads caused ≈ four times higher stress in restorative materials than the axial ones. It is noticeable that high values of von Mises stress are measured at the bottom of the sharp lesion, even up to 240 MPa, that are significantly reduced after the restoration. The highest stresses at the restorative material are present at the lower (gingival) margin of the restoration. The highest stresses under both types of loads are measured in nanohybrid composite (Tetric EvoCeram, Ivoclar Vivadent). The lowest values of the stress are measured in the flowable composite (Tetric Flow, Ivoclar Vivadent), but at the same time, the highest value of the stress is measured in the surrounding dental tissues on the tooth restored with the flowable composite. The microhybrid composite (Herculite XR, Kerr), with the highest safety factor, is the material that best withstands the stresses it is exposed to. The obtained safety factor did not exceed the critical limit, except for the glass ionomer cement, with the safety factor lower than 1. Conclusion  The type of tooth loading has the greatest influence on the intensity of stress. The value of the obtained stresses in the restorative material and dental tissues differ due to the different mechanical properties of the materials. Restoration of noncarious lesions significantly reduces extremely high stress values at their bottom.

Introduction: Perceptions of the esthetic appearance of teeth vary in different individuals and can affect satisfaction with the dental appearance, attitudes, and the need for appropriate dental treatment. The research aims to examine the factors influencing the satisfaction with the appearance of the dentition and the attitude toward treatments which improve dental esthetics among students of the faculty of dentistry in comparison to the attitudes of students of non-dental faculties.Methods: The research included a total of 358 students of the Faculty of Dentistry and Faculty of Architecture in Sarajevo who voluntarily filled out a questionnaire created for this research. The questionnaire contained questions related to satisfaction with the appearance of teeth in general, tooth color, tooth position, questions related to the previous, and future desired esthetic restorations and treatments.Results: Female subjects expressed statistically significantly greater dissatisfaction with the appearance of the dentition and did or plan to do treatments that could improve dental esthetics compared to male subjects. Students of the Faculty of Dentistry at final years were significantly more satisfied with the general appearance of teeth and tooth color compared to freshmen students of the Faculty of Dentistry and students of the Faculty of Architecture.Conclusion: Satisfaction with dental appearance is a subjective experience that is influenced by various factors, level, and type of education is among them.

OBJECTIVE Tumors of the brain and spine make up about 20% of all childhood cancers; they are the second most common form of childhood cancer after leukemia. Brain tumors are the most common solid tumor in children. Symptoms depend on a variety of factors, including location of the tumor, age of child, and rate of tumor growth. The aim of study was to present our experience with the diagnosis and treatment of brain tumors in children. PATIENTS AND METHODS The aim of this study is to analyze clinicopathological characteristics, treatments, complications, and outcomes in children with brain tumors. This study is a retrospective analysis of 27 consecutive patients younger than 16 years and hospitalized for surgical treatment of brain tumors. Intracranial hypertension, neurological status, radiological computerized tomography (CT) or magnetic resonance imaging (MRI) findings, tumor localization, type of resection, hydrocephalus treatment, histopathology, complications, and outcome were analyzed. RESULTS Twenty-seven surgeries were performed in patients for brain tumors. There were 9 females and 18 males. The average patient age was 7.8 years. There were 11 (40%) children with astrocytoma; of these, there were 9 (82%) pilocytic astrocytomas and 2 (18%) ordinary histopathological subtypes of high-grade tumors. CONCLUSION As with any cancer, prognosis and long-term survival vary greatly from child to child. Prompt medical attention and aggressive therapy are important for the best prognosis. Continuous follow-up care is essential for a child diagnosed with a brain tumor.

OBJECTIVE To evaluate and compare the solubility of three luting cements in three different solutions: distilled water and artificial saliva with different pH values (7.4 and 3.0). MATERIALS AND METHODS 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 solubility of the cements was calculated by weighing the specimens before and after immersion and desiccation. Values of solubility in water (Wsl) in microgram/mm3 for each of the five specimens were calculated using the following formula (ISO 4049:2009): Wsl=(m1-m3)/V. The Mann-Whitney U nonparametric statistical method and Post hoc sample comparisons were applied. RESULTS GC Fuji Plus showed statistically significant higher solubility in comparison with Variolink II and Multilink Automix in all three solutions. In acidic artificial saliva (pH 3.0) Multilink Automix showed significantly higher values of solubility compared to Variolink II (P<0.016). By studying the effect of pH value on the solubility of GC Fuji Plus cement, significantly higher values of solubility in pH 3.0 artificial saliva were confirmed (P<0.009). The influence of the surrounding pH value on the solubility of the resin cements Multilink Automix and Variolink II was researched. No statistically significant difference was found. CONCLUSION Solubility values were mainly influenced by the proportion of hydrophilic matrix, the type and composition of filler, and the pH value of the solutions.

OBJECTIVE The aim of this paper was to analyze the distribution of stress and deformation on the mandibular first premolar under two types of loading (axial and para-axial load of 200 N) using the FEM computer method. MATERIALS AND METHOD For this research a µCT scan of the first mandibular premolar was used, and the method used in this research was FEM analysis under two types of loading. RESULTS The values of the von Mises stress measured in the cervical part of an intact tooth under axial load were up to 12 MPa, and under paraaxial load over 50 MPa. The values of the stress measured on the bottom of the noncarious lesion are very high ≈ 240 Mpa. Stress values in the cervical part of the intact tooth are higher in the zone of the sub-surface enamel. The deformation values of the tooth under para-axial loading were ≈ 10 times higher than the value of the deformation under axial load. The greatest deformations were seen in the area of the tooth crown. CONCLUSIONS Occlusal loading leads to significant stress in the cervical part of teeth. The values of the measured stress are greater under the action of paraxial load. The values of stress in abfraction lesions measured under a paraxial load are extremely high. Exposing the lesion to further stress will lead to its deepening. The total deformation of the entire tooth under paraxial load was ≈ 10 times higher compared to the deformation value of the tooth under axial load.

Aim: The aim of this study was to compare time of preparation and canal aberrations in a simulated root canals after using three different rotary systems: Endostar E5, Endostar E3 and T One File Gold. Materials and Methods: A total of 90 endodontic training blocks were used in this study and divided into three groups consisting of 30 each (n = 30). Blocks processing was performed by thirty dentists without any prior experience in rotary instrumentation techniques. In the first group blocks were prepared using Endostar E5, in second one with Endostar E3 and in third one with T One File Gold system. The preparation time was measured. The postoperative image of each block was taken by stereomicroscope and canal aberrations (ledge and instrument fracture) was recorded. Statistical analysis was done by SPSS software. Results: Instrumentation with T One File Gold system is significantly faster compared to instrumentation with Endostar E5 and Endostar E3 systems (p <0.05). There are no statistically significant differences in the type and number of procedural errors between Endostar E5, Endostar E3 and T One File Gold systems when the operators have no previous experience in rotary instrumentation techniques. Conclusion: Under the conditions of this study, the incidence of examined canal aberrations were similar for all tested systems. The preparation time was significantly shorter with single file system.

Introduction: One of the most frequently used method for scanning patients with indication for dental implantation in dentistry is cone beam computed tomography. Implantation, CBCT imaging and implant programme are inevitable when planning a successful replacement of lost teeth. CBCT offers exact information about available bone and its density, adjacent tooth roots, the place of mandibular canal and maxillary sinus and adjacent anatomical structure. Aim: The goal of this study is to estimate accuracy of measurements on CBCT images ofpatients who have implants of different producers and determine if there is any statistically significant correlation between four test groups regardless of the alloy of which implants are made. Material and methods: The study was a prospective-comparative, and included fifteen patients with hundred dental implants divided in four groups depending on the producer. Results: Over dimensioning in the gained measurements of the whole sample on CBCT images in relation to dimensions of producers is between 0.1006mm and 0.368mm. Even though over dimensioning is measured in millimetres, it has to be taken into consideration in clinical practice when planning an implant placement, and we can recommend safety zone of 0.5mm. There have been no statistically significant differences in the gained results in over dimensioning of implants of different alloys for horizontal and vertical measurements on CBCT images of Astra Tech, Brendet titanium implants and Straumann titanium-zirconium implants. Based on the goals of the study there have been confirmed statistically significant correlations of great value (from 0.841 to 0.936) of high level of importance between manufactured value of dimensions and average dimensions values gained through CBCT imaging in four types of implants (four test groups). The total exactness of measurements on CBCT scan in this research is 96.66% for horizontal measuring and 96.92% for vertical measuring. Therefore, we can conclude that CBCT as radiological method has an unavoidable importance in planning and successful realisation of dental implant procedure. Conclusion: Cone Beam Computed Tomography provides exact measurements of dimensions of placed dental implant in relation to dimensions of the producers of the implant because the material from which dental implants have been made does not significantly affect the precision of the measurement.

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: The purpose of the current study was to estimate the biocompatibility of endodontic sealers with different bases on L929 mouse fibroblasts permanent cell line using Multiscan EX Spectrophotometer. Materials and Methods: Endodontics sealers used in this study were GuttaFlow (Roeko) silicone based sealer, AH plus (De Tray-DENTSPLY) epoxy resin based, Apexit (Vivadent) calcium hydroxide based and Endorez (Ultradent) methacrylate based sealer. Sealer were tested trough time, freshly mixed 24 h, 48h and 7 days after setting. Biocompatibility was determinate on permanent cell lines L929 mouse fibroblasts trough cytotoxicity using MTT assay. Level of absorption was measured with multi scan EX spectrophotometer on length 420-600 nm. Results: Sealer based on calcium hydroxide Apexit Plus, GuttaFlow silicone based sealer and AH plus epoxy resin based sealer, have shown a low cytotoxicity through the all periods of time on culture of L292 mouse fibroblasts. Methacrylate based sealer, Endorez showed moderate cytotoxicity when freshly mixed and after 7 days. After 24 hours the visibility of the cells was 74,0% and after 48 hours 65,1%. which is slightly cytotoxic. Conclusions: According to results of this study there is a statistically significant difference among the groups p<0,05 for all the tested sealers. Apexit Plus, GuttaFlow and AH plus can be considered as biocompatibile. EndoREZ sealer which is based on methacrylate, after 7 days shows 50,1% of visible live cells which is considered as moderate cytotoxicity.

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.

Objective – The aim of this case report is to present the results of surgical treatment of a patient with the pineal germinoma. Case report – A 12-year-old patient presented with two months history of headache, nausea, and vomiting, following by neuro-ophthalmologic disturbances (Parinaud syndrome). Computed tomography of the head showed a 3 cm mass in the pineal region, followed by obstructive hydrocephalus, and magnetic resonance imaging showed a pineal gland lesion with heterogeneous enhancement on contrast studies, with surrounding peritumoral edema, suggesting pineal germinoma. The patient underwent surgery to place a ventricular-peritoneal shunt, and second surgery using the occipital interhemispheric transtentorial approach to remove the tumor totally. Conclusion – Pineal germinomas that compress adjacent structures result in a typical clinical syndrome with endocrine malfunction, hydrocephalus or neuro-ophthalmological disturbances. A multimodality approach, including chemotherapy, radiotherapy and surgery, can offer excellent chances of free survival, and even cure.

Adresa za dopisivanje Samra Korać DMD, MSc Sveučilište u Sarajevu Stomatološki fakultet Zavod za restorativnu stomatologiju i endodonciju Bolnička 4 a 1000 Sarajevo, Bosna i Hercegovina samragk@gmail.com Sažetak Svrha istraživanja bila je izmjeriti i usporediti unutarnju stabilnost boje triju svjetlosnopolimerizirajućih materijala i jednoga kemijski stvrdnjavajućeg nakon njihova ubrzanog starenja. Materijali i metode: Testovi za stabilnost boja obavljeni su na svjetlosnopolimerizirajućim kompozitima – nanopunjenju Filtek Supreme XT (3M ESPE), nanohibridu Tetric Evo Ceram (Ivoclar Vivadent) i mikrohibridu Herculite XRV (Kerr) te na samopolimerizirajućem kompozitu Bisfil II (Bisco). Svi uzorci bili su uronjeni u destiliranu vodu (37°C) i držani u tamnoj posudi 24 sata. Nakon toga podijeljeni su u tri skupine. Postupak ubrzanog starenja proveden je prema dvama protokolima – u vodenoj kupelji na 60°C i prema ISO-u 7491. Uzorci iz kontrolne skupine držani su u destiliranoj vodi 30 dana na temperaturi od 37°C. Razlike u boji – ∆E, računale su se iz koordinata CIE L*a*b* izmjerenih spektrofotometrom nasuprot bijeloj pozadini prije postupka starenja uzoraka i poslije njega. Razina osjetljivosti boje postavljena je na 1, a prihvatljivi šum na 3,5. Statistička analiza obavljena je uparenim t-testom i ANOVA-om (p≤0,05). Rezultati: Svi ispitani materijali pokazali su klinički neprihvatljive promjene boje nakon ubrzanog starenja u vodenoj kupelji, a fotostarenjem nastala je vidljiva promjena boje kod svih svjetlosnopolimerizirajućih kompozita. Nanokompozitni materijali značajno su promijenili boju i u kontrolnoj skupini. Zaključak: Unutarnja stabilnost boje testiranih materijala ovisi o uvjetima starenja i vrsti dentalnog kompozita. Kemijski stvrdnjavajući kompoziti pokazali su tijekom fotostarenja bolju stabilnost. Ključne riječi kompozitne smole; starenje; materijali, testiranje; boja 1 Katedra za restorativnu stomatologiju i endodonciju Stomatološkog fakulteta Sveučilišta u Sarajevu Department of Restorative Dentistry and Endodontics, Faculty of Dentistry, University of Sarajevo 2 Odjel za ispitivanje dentalnih materijala Akademskog centra za stomatologiju, Amsterdam (ACTA), Nizozemska Dental Materials Science Department, Academic Centre for Dentistry Amsterdam (ACTA) 3 Katedra za pretkliničku stomatologiju Stomatološkog fakulteta Sveučilišta u Sarajevu Departmet of Preclinical Dentistry, Faculty of Dentistry, University of Sarajevo