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Abstract Background Releasing of metal ions might implicate in allergic reaction as a negative subsequent of the corrosion of Stainless Steel (SS304) orthodontic wires. The aim of this study was to evaluate the corrosion resistance of zinc-coated (Zn-coated) SS orthodontic wires. Methods Zinc coating was applied on SS wires by PVD method. Electrochemical impedance spectroscopy (EIS), Potentiodynamic polarization tests and Tafel analysis methods were used to predict the corrosion behavior of Zn-coated and uncoated SS wires in both neutral and acidic environments. Results The values of Ecorr ,icorr and Rct ,which were the electrochemical corrosion characteristics, reported better corrosion behavior of Zn-coated SS wires against uncoated ones in both artificial saliva and fluoride-containing environments. Experimental results of the Tafel plot analyses were consistent with that of electrochemical impedance spectroscopy analyses for both biological solutions. Conclusion Applying Zn coating on bare SS orthodontic wire by PVD method might increase the corrosion resistance of the underlying stainless-steel substrate.

Abstract Objective The purpose of this study was to determine the students' attitudes before and after the flipped classroom, and the effectiveness of this method to promote the students' lateral cephalograms tracing abilities, students' satisfaction and their final exam scores. Materials and Methods This is a single‐group quasi‐experimental research conducted on dental students of Shiraz University of Medical Sciences (SUMS), Iran in 2019. The intervention was carried out in a blended learning approach with the flipped classroom model. Thirty‐five fourth‐year dental students participated in a flipped classroom held during a semester for the lateral cephalograms tracing course. The students were provided with the educational materials before the class time through multimedia learning tools and the class time was devoted to discussions. The students were asked to fill out four questionnaires (pretest/posttest attitudes, pretest/posttest self‐assessments of theoretical knowledge and practical skills in cephalograms, posttest of satisfaction from quality of the course, and posttest of students' views about effectiveness of blended learning tools) and final exam scores of students. Results Students' attitudes toward e‐Learning were improved after the flipped classroom and the quality of this method was acceptable to the students (p

Abstract Aim The purpose of this study was to evaluate the effect of the density and the thickness of the cortical and the cancellous bone at selected inter-radicular areas in subjects with different facial growth patterns using cone beam computed tomography (CBCT) in order to choose the optimal area for miniscrew insertion. Materials and methods From 150 CBCT scans, 45 scans were included in the study. The subjects were categorized into three groups based on their skeletal growth pattern according to SN-GoMe angle and facial height index. Cortical and cancellous bone density and thickness were measured at the selected inter-radicular areas. Results Compared to the other two groups, the hyperdivergent group had thinner cortical bone in the anterior region of the maxilla between the central and the lateral incisors on the buccal side at 4 mm from the alveolar crest (P-value: 0.012) and on the palatal side at 7 mm from the alveolar crest (P-value: 0.030). Cancellous bone density values in these areas were higher in subjects with hypodivergent and hyperdivergent growth pattern. Furthermore, in hyperdivergent group less dense cortical bone in the posterior region of the maxilla on the palatal side between the second premolar and the first molar (p-value: 0.020) and on the buccal side between the first molar and the second molar (p-value: 0.038 & 0.047) was observed. No significant differences were found in the mandible between the three groups. No significant differences were found between the male and the female subjects. Conclusion Hyperdivegents presented thinner cortical bone in the anterior of the maxilla between the central and the lateral incisors. Less dense cortical bone was found between maxillary second premolar and first molar on the palatal side and also between the maxillary first molar and the second molar on the buccal side in this group too. Normal showed higher density values in the posterior of the maxilla compared to the other two groups. No significant differences were found among three groups in mandible.

Abstract Aim Vitamin D plays an important role in immune system regulation, also its deficiency is assumed to affect the patients’ predisposition to viral diseases such as recurrent herpes labialis. In this cross-sectional study, we tried to compare the mean serum level of vitamin D in participants with a positive history of recurrent herpes labial lesions and healthy controls. Materials and methods The vitamin D serum level of 43 participants with a positive history of recurrent herpes labial lesions who were referred to the Motahhari laboratory in Shiraz during 2020–2022, was compared with 42 healthy controls. It was assessed by an Elisa kit. An Independent T-test was used to compare the vitamin D serum level between two genders. In order to assess the mean age value and gender distribution, an independent T-test and Pearson Chi-Square were used, respectively for the two groups. The serum vitamin D level was compared between both control and test groups. Results There was no significant difference between vitamin D mean serum levels in the two evaluated groups (p.value = 0.72). Although the age (p.value = 0.09) and recurrence (p.value = 0.13) of herpes labialis had no statistically significant relation to the vitamin D serum level, the healing duration of herpes labialis was inversely related (p.value = 0.01). Lower-level of serum vitamin D were accompanied by a longer healing duration of the lesions. Conclusion Although the vitamin D serum level of participants with a history of recurrent herpes labialis had no relation with age and herpes virus recurrence frequency, a longer healing duration of lesions had been reported in patients with lower serum levels of vitamin D.

Statement of the Problem: Medial depression of the mandibular ramus (MDMR) as a normal anatomical variation might complicate orthognatic surgeries that involve ramus. When planning an orthognatic surgery, it is clinically valuable to notice MDMR in osteotomy site to decrease the risk of failure.Purpose: The aim of present study was to evaluate the prevalence as well as characteristics of MDMR in three skeletal sagittal classifications.Materials and Method: This cross sectional study evaluated 530 cone beam computed tomography (CBCT) scans, of which 220 were enrolled. The skeletal sagittal classification, the presence of MDMR, the shape, depth, and width of MDMR were recorded for each patient by two examiners. Chi-square test was performed to determine the differences between three skeletal sagittal groups and between two genders.Results: The overall prevalence of MDMR was 60.45%. MDMR was mostly detected in class III (76.92%), followed by class II (76.66%), and class I (54.87%). In the analyzed CBCT scans, semi-lunar was the most common shape detected (42.85%), followed by triangular (30.82%), circular (18.04%), and tear-drop (8.27%). The depth of MDMR was not significantly different between three sagittal groups and between genders; however, the width of MDMR was higher in class III group and in male patients. In the present study, MDMR was found to be more common in patients with class II and class III skeletal classifications. Although, MDMR was more frequent in class III, the difference between class II and class III was not significant.Conclusion: More caution is needed during orthognatic surgery in patients with dentoskeletal deformities during the splitting of the ramus. Moreover, higher width of MDMR in class III and male patients should be concerned when planning an orthognatic surgery for these patients.

Statement of the Problem: The first permanent molar (FPM) teeth are the most important elements of mastication and are crucial in the improvement of functionally proper occlusion. However, in childhood, these teeth are most susceptible to caries. The loss of an FPM in a child can cause changes in the dental arches. These changes can occur throughout a person’s life. In such cases, the dentists and dental specialists need to decide whether to preserve or extract the FPM. Purpose: This study aimed to evaluate the extent of knowledge of dental specialists in Shiraz (Iran) on clinical guidelines for the preservation and extraction indications of FPMs. Materials and Method: The authors developed a dedicated questionnaire for the purpose of knowledge evaluation. A total of 6 orthodontists and 15 dental specialists, respectively confirmed the validity and reliability of the questionnaire. The 19-item questionnaire covered topics such as demographic data, preservation criteria for FPM teeth, and indications for FPM extraction. The survey was carried out across six dental disciplines in Shiraz (Iran) during July-August 2018. The data were analyzed using the SPSS software (version 22.0) with the dependent sample t test and one-way ANOVA. p Value< 0.05 was considered statistically significant. Results: Out of 89 dental specialists, 64 participants (53% male, 47% female) completed the questionnaire. The mean knowledge score for all participants was 10.09±3.93 (maximum of 19). The level of knowledge had a significant and inverse correlation with age (p< 0.001) and years of experience (p= 0.017). It also had a significant relationship with dental specialization (p< 0.001). Conclusion: The overall level of knowledge of the specialists was insufficient, except for the pedodontists and orthodontists. A re-education training program for dental specialists is strongly recommended.

Purpose: The aim of current study was to assess the glenoid fossa morphology among different vertical skeletal patterns using cone beam computed tomography (CBCT). Materials and Methods: The CBCT images of 63 patients with Class I sagittal skeletal pattern were classified into three groups based on posterior facial height (PFH)/ Anterior facial height (AFH) ratio. Each group divided in to normal, horizontal and vertical growth pattern groups. Depth, width and inclination of glenoid fossa were measured and assessed on CBCT images. One-way analysis of variance (ANOVA) and Tukey post-hoc test were used to compare mean values of measured variables among the groups. Results: The width (28.76±0.79) and depth (14.61±0.514) of glenoid fossa were lower in horizontal in comparison to vertical and normal growth patterns (p-value

Lavandula angustifolia Mill. (lavender) is known for its antibacterial, muscle relaxant, antispasmodic, sedative, and anesthetic effects, and is also proposed to be used as an analgesic agent. Despite several studies on the analgesic activity of lavender, this is the first experiment in patients with orthodontic pain. This "2-arm parallel" study aims to evaluate the effect of lavender oil inhalation on reducing pain after elastomeric separator placement as a part of orthodontic treatment. Patients who needed elastic separator placement in mesial and distal of first permanent molars of all quadrants prior to their first-ever fixed orthodontic treatment, with the age range of 20 to 24, were randomly assigned to one of the two study groups: lavender oil and sesame oil. Participants had to breathe in their medication for 2 minutes just before separator insertion, as well as 4, 8, 12, 24, 36, and 48 h afterward. A visual analog scale (VAS) was used to measure the level of pain during three oral situations, including rest, fitting posterior teeth, and chewing at the following periods: just before separator placement (T0), immediately after insertion (T1), 3 h post-insertion (T2), 12 h post-(T3), 24 insertion h post-insertion (T4), and 48 h after separator placement (T5). The current study indicated the effectiveness of lavender oil inhalation in reducing pain perception while chewing 48 h after elastic separator placement. The pain level in lavender inhalation was lower from 12 h to 48 h after separator insertion, although not considerable, indicating the probability of its effectiveness on delayed responses to orthodontic pain.

The aim of this study was to evaluate the mechanical properties of stainless steel (SS) orthodontic wires coated with zinc (Zn), using a Physical Vapored Deposition (PVD) machine. A total of 100 straight SS orthodontic wires were cut into pieces of 5 centimeters in length and were divided into two groups. Half of the wires were coated with Zn using a PVD machine, and the others remained uncoated. Tensile strength (n = 15), three-point bending (n = 15), and frictional resistance at 0° (n = 10) and 10° (n = 10) were measured to compare the mechanical properties of the Zn-coated and uncoated orthodontic wires using the universal testing machine. The surface of the coated wires was observed by SEM and AFM. An independent t-test, multivariate ANOVA, and measurement ANOVA were used for data analysis. SEM and AFM showed a homogenous Zn layer of 0.28 ± 0.006 µm on the SS wires. The tensile strength and three-point bending strength significantly increased after Zn coating of wires with the PVD method (P0.05). Coating with Zn improved the tensile and load-bending strength of SS orthodontic wires and reduced their frictional resistance which might be advantageous in terms of reducing the risk of root resorption during the orthodontic treatment.

Objectives: Various methods have been introduced for evaluation of tooth movement in orthodontics. The challenge is to adopt the most accurate and most beneficial method for patients. This study was designed to introduce analysis of digital photographs with Auto- CAD software as a method to evaluate tooth movement and assess the reliability of this method. Materials and Methods: Eighteen patients were evaluated in this study. Three intraoral digital images from the buccal view were captured from each patient in half an hour inter- val. All the photos were sent to AutoCAD software 2011, calibrated and the distance be- tween canine and molar hooks were measured. The data was analyzed using intraclass cor- relation coefficient. Results: Photographs were found to have high reliability coefficient (P > 0.05). Conclusion: The introduced method is an accurate, efficient and reliable method for eval- uation of tooth movement.

path of microleakage between the enamel and adhesive potentially allows microbial ingress that may consequently cause enamel decalcification. The aim of this study was to compare microleakage of brackets bonded either by laser or acid etching techniques.The specimens were 33 extracted premolars that were divided into three groups as the acid etching group (group 1), laser etching with Er:YAG at 100 mJ and 15 Hz for 15s (group 2), and laser etching with Er:YAG at 140 mJ and 15 Hz for 15s (group 3). After photo polymerization, the teeth were subjected to 500 thermal cycles. Then the specimens were sealed with nail varnish, stained with 2% methylen blue for 24hs, sectioned, and examined under a stereomicroscope. They were scored for marginal microleakage that occurred between the adhesive-enamel and bracket-adhesive interfaces from the occlusal and gingival margins. Data were analyzed with the Kruskal- Wallis test.For the adhesive-enamel and bracket-adhesive surfaces, significant differences were not observed between the three groups.According to this study, the Er:YAG laser with 1.5 and 2.1 watt settings may be used as an adjunctive for preparing the surface for orthodontic bracket bonding.