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Background: The coronavirus disease (COVID) is predicted to cause serious mental health problems among healthcare providers (HCPs) especially dentists. Also understanding the influencing factors of the acceptance of COVID-19 vaccination among HCPs are important aspects in the design of effective strategies to improve the vaccine coverage rate. Therefore, this study aimed to assess the knowledge, vaccination acceptance, fear, and obsession, as well as the preventive practice behaviors of Iranian dentists and dental students in late 2020 toward COVID-19., Materials and Methods: A descriptive, web-based cross-sectional survey was conducted among Iranian dental students and dentists (general practitioners and specialists). All Iranian dentists and dental students living in the Islamic Republic of Iran regardless of their city and workplace were invited to participate in the study. The total number of dentists in Iran was estimated to be 54,927. The sample size was calculated 380. The questionnaires used in this study were adapted from previously published studies based on the authors' permission. The questionnaire consisted of four sections that sought to collect information on the respondents' vaccination acceptance, knowledge, preventive practice, fear, and obsession toward COVID-19. The relationship between the study variables was assessed using Pearson's correlation coefficient and also multiple linear regression tests., Results: Overall, 394 dentists were filled the questionnaire (65 dental students, 151 general dentists and 178 specialists). There were no differences in terms of vaccination acceptance, knowledge and also fear score in different designation groups. Dentists had significantly higher obsession and also preventive practice scores than other designation groups ( P < 0.05). The majority of respondents had good knowledge (more than 9), acceptable preventive practice (more than 19), low fear-obsession (<2.7), and high acceptance of COVID-19 vaccination (more than 8.8)., Conclusions: Although obsession and fear scores were low in all designation groups, dentists had higher obsession and also preventive practice scores than other designation groups. More than half of respondents preferred imported COVID-19 vaccines. Finally, organizations such as the World Health Organization and the Ministry of Public Health in Iran should increase vaccine convenience and accessibility in terms of vaccine importing, distribution, supply, and immunization service., Competing Interests: There are no conflicts of interest., (Copyright: © 2022 Journal of Education and Health Promotion.)

Stars and planets both form by accreting material from a surrounding disk. Because they grow from the same material, theory predicts that there should be a relationship between their compositions. In this study, we search for a compositional link between rocky exoplanets and their host stars. We estimate the iron-mass fraction of rocky exoplanets from their masses and radii and compare it with the compositions of their host stars, which we assume reflect the compositions of the protoplanetary disks. We find a correlation (but not a 1:1 relationship) between these two quantities, with a slope of >4, which we interpret as being attributable to planet formation processes. Super-Earths and super-Mercuries appear to be distinct populations with differing compositions, implying differences in their formation processes.

As an exoplanet transits its host star, some of the light from the star is absorbed by the atoms and molecules in the planet's atmosphere, causing the planet to seem bigger; plotting the planet's observed size as a function of the wavelength of the light produces a transmission spectrum. Measuring the tiny variations in the transmission spectrum, together with atmospheric modelling, then gives clues to the properties of the exoplanet's atmosphere. Chemical species composed of light elements-such as hydrogen, oxygen, carbon, sodium and potassium-have in this way been detected in the atmospheres of several hot giant exoplanets, but molecules composed of heavier elements have thus far proved elusive. Nonetheless, it has been predicted that metal oxides such as titanium oxide (TiO) and vanadium oxide occur in the observable regions of the very hottest exoplanetary atmospheres, causing thermal inversions on the dayside. Here we report the detection of TiO in the atmosphere of the hot-Jupiter planet WASP-19b. Our combined spectrum, with its wide spectral coverage, reveals the presence of TiO (to a confidence level of 7.7σ), a strongly scattering haze (7.4σ) and sodium (3.4σ), and confirms the presence of water (7.9σ) in the atmosphere.

Introduction: The smile is a key facial expression, and a careful assessment of the facial profile in smiling is an essential part of a complete orthodontic diagnosis. The aim of this study was to determine the preferred maxillary incisor inclination in the smile profile with regard to different mandibular positions., Methods: A smiling profile photograph of a man with normal facial profile features was altered digitally to obtain 3 different mandibular sagittal positions in 4-mm decrements or increments from -4 to +4 mm. In each mandibular position, the inclination of the maxillary incisors was changed from -10° to +10° in 5° increments. A total of 234 raters (72 senior dental students, 24 orthodontists, 21 maxillofacial surgeons, 25 prosthodontists, and 92 laypeople) were asked to score each photograph using a Likert-type rating scale. Mann-Whitney, Kruskal-Wallis, and intraclass correlation coefficient tests were used to analyze the data., Results: In retruded and protruded mandibles, normal incisor inclination and the most retroclined incisors were selected as the most and the least attractive images, respectively, by almost all groups. With an orthognathic mandible, the image with the most retroclined incisors was selected as the least attractive, but the raters were not unanimous regarding the most attractive image. The intraclass correlation coefficient was 0.82 (high level of agreement). Also, the sex of the raters had no effect on the rating of the photographs., Conclusions: It is crucial to establish a normal incisor inclination, especially in patients with a mandibular deficiency or excess. An excessive maxillary incisor lingual inclination should be avoided regardless of the mandibular position., (Copyright © 2015 American Association of Orthodontists. Published by Elsevier Inc. All rights reserved.)

Statement of the Problem: The validity of the Index of Complexity, Outcome and Need (ICON) which is an orthodontic index developed and introduced in 2000 should be studied in different ethnic groups., Purpose: The aim of this study was to perform an analysis on the ICON and to verify whether this index is valid for assessing both the need and complexity of orthodontic treatment in Iran., Materials and Method: Five orthodontists were asked to score pre-treatment diagnostic records of 100 patients with a uniform distribution of different types of malocclusions determined by Dental Health Component of the Index of Treatment Need. A calibrated examiner also assessed the need for orthodontic treatment and complexity of the cases based on the ICON index as well as the Index of Orthodontic Treatment Need (IOTN). 10 days later, 25% of the cases were re-scored by the panel of experts and the calibrated orthodontist., Results: The weighted kappa revealed the inter-examiner reliability of the experts to be 0.63 and 0.51 for the need and complexity components, respectively. ROC curve was used to assess the validity of the index. A new cut-off point was adjusted at 35 in lieu of 43 as the suggested cut-off point. This cut-off point showed the highest level of sensitivity and specificity in our society for orthodontic treatment need (0.77 and 0.78, respectively), but it failed to define definite ranges for the complexity of treatment., Conclusion: ICON is a valid index in assessing the need for treatment in Iran when the cut-off point is adjusted to 35. As for complexity of treatment, the index is not validated for our society. It seems that ICON is a well-suited substitute for the IOTN index.

Background: This study aims to evaluate and compare the effect of pre-procedural administration of acetaminophen, ibuprofen, and meloxicam in reducing pain after separator placement., Methods: Three hundred twenty-one patients who needed orthodontic treatment and aged above 15 were randomly assigned to one of the three study groups: group A: 650 mg acetaminophen, group B: 400 mg ibuprofen, and group C: 7.5 mg meloxicam. All subjects received a single dose of medication 1 h prior to separator placement. Using visual analog scale, patients recorded their pain perception during rest, fitting posterior teeth together, and chewing at time intervals of immediately, 2, 6, 24, and 48 h after separator placement., Results: There was no significant difference between acetaminophen, ibuprofen, and meloxicam in post-separator placement pain control when administered 1 h before the procedure. In all the groups, at rest, pain level elevated after separator placement and reached its peak at 24 h and then subsided until 48 h. But during chewing and fitting of the posterior teeth, some of the groups reached a peak in pain at 48 h. No significant difference was found in pain experience between males and females., Conclusions: Meloxicam can be used as an effective analgesic in orthodontic pain control considering it has less gastric side effects compared to the conventional nonsteroidal anti-inflammatory drugs., Trial Registration: Iranian Registry of Clinical Trials, IRCT2015041821828N1.

Background: Different environmental conditions, such as high temperature or exposure to some chemical agents, may affect the force decay of different methods of space closure during orthodontic treatment. The aim of this in vitro study was to evaluate the force decay pattern in the presence of tea as a popular drink in some parts of the world and two mouthwashes that are usually prescribed by the orthodontist once the treatment is in progress., Materials and Methods: Elastic chain (EC), nickel-titanium (Ni-Ti) closed coil spring and tie-back (TB) method were used as the means of space closure. The specimens were placed in five different media: Hot tea, hot water (65°), chlorhexidine mouthwash, fluoride mouthwash and the control group (water at 37°). The specimens were stretched 25 mm and the elastic force of three systems was measured at the beginning of the study, after 24 h, after 1 week and after 3 weeks. One-way ANOVA was used to compare the results between the groups and Duncan test was carried out to compare the sets of means in different groups (P ≤ 0.05)., Results: Tea increases the force decay in the EC and TB groups. Oral mouthwashes also resulted in more rapid force decay than the control group. EC and Ni-Ti groups were not much affected in the presence of oral mouthwashes., Conclusion: Regarding the immersion media, TB method showed the biggest variation in different media and Ni-Ti coil spring was least affected by the type of media.

Objectives: This study was designed to assess the relationship between postsurgical cephalometric changes and quality of life and satisfaction after orthognathic surgery., Material and Methods: Sample size consisted of 30 patients with class III and 25 patients with class II malocclusion treated with bilateral sagittal split osteotomy and Le Fort I osteotomy. Profile convexity, lower facial height proportion, lip position and length, nose, and chin position were measured on pre and post-treatment cephalograms. To assess the patients' satisfaction and quality of life (QoL) after surgery, the questionnaire of the Rustemeyer's study and Oral Health Impact Profile (OHIP) questionnaire were used, respectively. The paired-sample t-test, Spearman correlation analysis and Pearson correlation analysis was used in SPSS statistical software., Results: In class III malocclusion patients, decrease in facial angle, convexity angle, mentolabial angle, and increase in upper lip protrusion had the most positive impact on QoL. Decrease in facial angle and increase in upper lip protrusion were correlated positively with satisfaction questionnaires. In class II malocclusion patients, increase in convexity angle, facial angle and mentolabial angle had the most positive impact on satisfaction and QoL., Conclusions: Consideration both subjective and objective parameters affecting on the patients' satisfaction and their quality of life is essential.

Objective: This study evaluated the effect of superpulse CO2 laser irradiation and deglazing of porcelain surfaces on the shear bond strength (SBS) of metal orthodontic brackets, and compared it with two conventional etching techniques., Methods: Forty-eight Feldspathic porcelain fused to metal specimens embedded in cylindrical acrylic resin tubes were fabricated, and all the specimens were divided into four groups. In Group 1, the specimens were roughened with a diamond bur and etched with hydrofluoric acid (HFA) gel for 4 min. In Group 2, the specimens were roughened with a bur and irradiated by a CO2 laser with a 2 W power setting for 20 sec. In Group 3, the specimens were only irradiated by a CO2 laser. In Group 4, the porcelain surface was sandblasted with 50 μm aluminum oxide. Before bonding, the bracket silane was applied on the porcelain surfaces. SBS was evaluated by a Universal testing machine (Zwickroll, Germany). The remaining adhesive after the bond failure was evaluated using an adhesive remnant index (ARI). Statistical analysis was conducted by analysis of variance (ANOVA), Tukey, and Kruskal-Wallis tests., Results: ANOVA revealed significant differences in SBS among the four groups (p<0.001). Group 1 demonstrated significantly higher bond strength (13.13±2.47) when compared with the other groups. Group 2 showed higher bond strength (9.60±1.91) when compared with group 4 (6.40±1.67) (p=0.016). Group 1 displayed the highest ARI scores among the groups., Conclusions: Deglazing combined with HFA etching produced the highest bond strength, but CO2 laser irradiation provided adequate bond strength and allowed for elimination of the HFA step. Deglazing is not recommended as a preliminary step before CO2 laser conditioning.

Background: Two-dimensional projection radiographs have been traditionally considered the modality of choice for cephalometric analysis. To overcome the shortcomings of two-dimensional images, three-dimensional computed tomography (CT) has been used to evaluate craniofacial structures. However, manual landmark detection depends on medical expertise, and the process is time-consuming. The present study was designed to produce software capable of automated localization of craniofacial landmarks on cone beam (CB) CT images based on image registration and to evaluate its accuracy., Methods: The software was designed using MATLAB programming language. The technique was a combination of feature-based (principal axes registration) and voxel similarity-based methods for image registration. A total of 8 CBCT images were selected as our reference images for creating a head atlas. Then, 20 CBCT images were randomly selected as the test images for evaluating the method. Three experts twice located 14 landmarks in all 28 CBCT images during two examinations set 6 weeks apart. The differences in the distances of coordinates of each landmark on each image between manual and automated detection methods were calculated and reported as mean errors., Results: The combined intraclass correlation coefficient for intraobserver reliability was 0.89 and for interobserver reliability 0.87 (95% confidence interval, 0.82 to 0.93). The mean errors of all 14 landmarks were <4 mm. Additionally, 63.57% of landmarks had a mean error of <3 mm compared with manual detection (gold standard method)., Conclusion: The accuracy of our approach for automated localization of craniofacial landmarks, which was based on combining feature-based and voxel similarity-based methods for image registration, was acceptable. Nevertheless we recommend repetition of this study using other techniques, such as intensity-based methods.

Statement of the Problem: Fixed retainers were developed to maintain incisor alignments after orthodontic treatments. Although the effects of fixed retainers on periodontal health are clinically studied, no studies have still evaluated the histological changes in the periodontium after the placement of thefixed retainers., Purpose: The aim of this study was to evaluate the effects of customised retainers on periodontium histologically., Materials and Method: Forty pairs of maxillary and mandibular central incisors of twenty rabbits were randomly divided into four equal groups: The first group was considered as the control and in the second group, Fiber Reinforced Composite (FRC), in the third group, 0.014 inch stainless steel (SS) wire and in the fourth group, 0.175 inch multistrand stainless steel (MSS) wire were bonded on the labial surfaces of the incisors. After sixty days; animals' periodontium were evaluated histologically., Results: The number of bone resorption lacuna in the control group was significantly less than FRC and 0.014 SS groups. The periodontal vessel count and their diameter in the control group was significantly lower than the other groups. The pulp vessel count and their diameter in controls were significantly more than the 0.014 SS and the 0.175 MSS groups., Conclusion: Findings of this study suggest that FRC fixed retainer might cause detrimental effects on the periodontal ligaments and supporting bone and the 0.014- inch and 0.175- inch fixed retainers can cause hyalinization and possibly the necrosis of the pulp.

Background: The purpose of this study was to compare the occlusal peer assessment rating (PAR) index in Class I patients treated by means of Begg and Edgewise methods., Materials and Methods: The pre- and post-treatment study models of Class I patients, referred to two private clinics, treated with Begg method (n = 30) and standard Edgewise method (n = 30), were reviewed retrospectively using PAR index including dental displacements, buccal occlusion (anteroposterior, vertical and transverse), overjet, overbite and midline parameters. The changes in PAR indices were analyzed using paired t-test. A P < 0.05 was considered as statistically significant., Results: There was no significant difference in sex and age distribution between the two groups. The improvement of buccal occlusion in patients treated by Begg method (1.51 ± 0.39) was significantly higher than that of patients treated by Edgewise method (0.28 ± 0.39). The duration of treatment in Begg method (17.8 ± 1.3 months) was significantly shorter than that of Edgewise method (23.7 ± 1.3 months). However, there were no significant differences between the two methods in terms of total PAR index, dental displacements, overjet, overbite and midline., Conclusion: In conclusion, findings of the present study indicated that Begg method might be associated with better improvement of buccal occlusion and shorter duration of treatment.

Introduction: All parts of the face, other than jaw relationships, should be considered in orthodontic treatment planning. The role of forehead and neck in facial esthetics is well known; however, the majority of conventional facial analysis methods have not considered them. Neck and forehead may confer mutual effects on equilibrium and on esthetics of other facial components, and may change the overall convexity/concavity view of the profile. Therefore, the aim of this study was to assess the effect of anteroposterior position of the forehead and neck on the esthetics of skeletal class I, II and III jaw relationships using profile silhouettes., Methods: Class II and III jaw relationships were constructed on the silhouette of a class I normal profile by altering the mandibular position. Retruded, normal and protruded positions were also applied for the forehead and neck. Three hundred Iranian laypeople (150 men, 150 women) scored the esthetics of profile silhouettes from 1 to 7. Half of the participants were told to consider the profiles as a man, and the other half were told to consider them as a woman. Data were analyzed using non-parametric methods., Results: Class I jaw relation was found to be the most beautiful profile followed by class II and III respectively. Esthetics of different positions of the neck and forehead were significantly different (P < 0.05). In subjects with a normal neck and forehead position, and those with a retruded neck, the best esthetic relationship was class I, and the worst was class III. For protruded foreheads, the best jaw relationship was class II for females and class I for males, and the worst was class III for both. In a retruded forehead position, the most preferred jaw relationship was class I, and the worst was class II. For profiles with a protruded neck, the best esthetics was found to be in class III jaw relationship, and the worst was in class II. There was a small difference in scoring for male and female profiles (P < 0.05); there were also small differences in scoring trends of men and women (P < 0.05)., Conclusion: This study showed that the anteroposterior position of the forehead and neck affects the esthetics of jaw relationships in profile view. In laypeople's opinions, in a normal profile, the overall appearance is more important compared to the independent position of the neck and forehead; however, having jaw abnormalities, the neck plays an important independent role. The preferred jaw relation for profiles with each forehead or neck position was introduced.

Background: Most orthodontists believe that fixed retainers are necessary to maintain ideal dental relationships. However, untoward side effects might result from their long-term placement. The aim of this study was to evaluate the clinical and radiographic effect of two commonly used fixed retainers on the health of the periodontium., Methods: Thirty patients were randomly divided into two groups to receive either a fiber-reinforced composite retainer or a spiral wire retainer extended on the lingual surfaces of both maxillary and mandibular arches from canine to canine. Periapical radiographs were obtained from the patients at the time of placement of the retainers and after the 6-month period to assess the radiographic conditions of the periodontium. Clinical examination was carried out at the same two time intervals., Results: Even though there were no significant differences between the two groups of study at the beginning of the trial, there were statistically significant differences after the 6-month follow-up regarding the main outcomes of the study. Nearly all indices showed to deteriorate after 6 months in the fiber-reinforced group, while in the spiral wire group, this was not the case. As for the secondary outcomes, radiographic examination did not reveal any statistically significant differences after 6 months or between the two groups., Conclusions: It can be concluded that spiral wire retainers elicit less detrimental periodontal response in the short-term follow-up compared to fiber-reinforced composite retainers as revealed by the primary outcomes of the study., Trial Registration: ClinicalTrials.gov: NCT01314729.

Introduction: Nocturnal enuresis has been found a common symptom among children with breathing problems and sleep apnea. The purpose of this study was to evaluate the therapeutic and placebo effects of slow maxillary expansion on nocturnal enuresis., Material and Methods: Four children with enuresis aged 7-12 years were selected. Rigid acrylic expansion appliances were fabricated and delivered to them. Frequency of enuresis was recorded by the parents during three stages: 1) before appliance delivery; 2) after appliance insertion without expansion; and 3) during expansion and retention., Results: The frequency of wetting decreased significantly during the period of appliance use without expansion. During the expansion and retention phase, two patients became completely dry, and two patients improved significantly., Conclusions: Maxillary expansion can have a positive effect on the treatment of nocturnal enuresis. Also, the placebo effect of the expansion appliance has significant effects on enuresis.

Objectives: To our knowledge, there is no study regarding the effects of facial type (short face or long face) on the esthetic perception of smiles as related to the amount of tooth and gingival display., Materials and Methods: Four photographs from two long- and two shortfaced females with posed smiles were prepared and, with altering the amount of tooth display, 5 photos for each of them were produced. These photos were given to 62 dentists and 69 laypersons to rate the images., Results: There were significant differences between short and long-face patterns in low and high smile lines; also there were significant differences between dentists and laypersons about some images. Smile lines consistent with gingival margin were the best for both short and long-face patterns; also 1.5 mm incisor coverage in short-face and 1.5 mm gingival display in long-face received as high scores., Conclusion: In short-face patterns, lower smile lines, and in long-face patterns, higher smile lines are more acceptable by both dentists and laypersons, which can help in designing orthodontic treatment goals.

Statement of Problem: One of the major outcomes of orthodontic treatment is the apical root resorption of teeth moved during the treatment. Identifying the possible risk factors, are necessary for every orthodontist., Purpose: The aim of this study was to compare the rate of apical root resorption after fixed orthodontic treatment with standard edgewise and straight wire (MBT) method, and also to evaluate other factors effecting the rate of root resorption in orthodontic treatments., Materials and Method: In this study, parallel periapical radiographs of 127 patients imaging a total of 737 individual teeth, were collected. A total of 76 patients were treated by standard edgewise and 51 patients by straight wire method. The periapical radiographs were scanned and then the percentage of root resorption was calculated by Photoshop software. The data were analyzed by Paired-Samples t-test and the Generalized Linear Model adopting the SPSS 15.0., Results: In patients treated with straight wire method (MBT), mean root resorption was 18.26% compared to 14.82% in patients treated with standard edgewise technique (p< .05). Male patients had higher rate of root resorption,statistically significant (p< .05). Age at onset of treatment, duration of treatment, type of dental occlusion, premolar extractions and the use of intermaxillary elastics had no significant effect on the root resorption in this study., Conclusion: Having more root resorption in the straight wire method and less in the standard edgewise technique can be attributed to more root movement in pre-adjusted MBT technique due to the brackets employed in this method.

Objective: The purpose of this study was to compare the bond strength of orthodontic brackets using laser versus acid etching., Background Data: Debonding of brackets is a common problem in orthodontic treatments., Materials and Methods: Eighty extracted premolar teeth were divided into two groups. The enamel of the teeth in group A and B were etched using CO2 laser and phosphoric acid, respectively. The brackets were bonded to the teeth using Transbond XT and then debonded from the teeth by Instron machine. The remaining composite on the tooth surface was removed by a tungsten carbide polishing bur. Both groups were divided into two subgroups (A1, A2 and B1, B2). The teeth were prepared again with laser in A1, B1 subgroups and with acid in A2, B2 subgroups. At each stage, the shear bond strength and residual adhesive index were measured. One way ANOVA and χ(2) tests were used to analyze data., Results: The mean shear bond strength was significantly lower in group A and higher in group B compared with all other groups (p < 0.05). Most of the bond failures were degree 0 and 1 in groups A, A1, and B1, and degree 2 and 3 in groups B, A2, and B2., Conclusions: Primary preparation with acid has a higher bond strength value than does CO2 laser. Less adhesive residue remained on enamel after tooth preparation with laser following debonding. Secondary preparation of the enamel using laser has higher bond strength value than does primary preparation with laser, which can rationalize use of laser in rebonding of brackets.

Objectives: The purpose of this study was to design software for localization of cephalometric landmarks and to evaluate its accuracy in finding landmarks., Methods: 40 digital cephalometric radiographs were randomly selected. 16 landmarks which were important in most cephalometric analyses were chosen to be identified. Three expert orthodontists manually identified landmarks twice. The mean of two measurements of each landmark was defined as the baseline landmark. The computer was then able to compare the automatic system's estimate of a landmark with the baseline landmark. The software was designed using Delphi and Matlab programming languages. The techniques were template matching, edge enhancement and some accessory techniques., Results: The total mean error between manually identified and automatically identified landmarks was 2.59 mm. 12.5% of landmarks had mean errors less than 1 mm. 43.75% of landmarks had mean errors less than 2 mm. The mean errors of all landmarks except the anterior nasal spine were less than 4 mm., Conclusions: This software had significant accuracy for localization of cephalometric landmarks and could be used in future applications. It seems that the accuracy obtained with the software which was developed in this study is better than previous automated systems that have used model-based and knowledge-based approaches.

To provide quantitative data about the prevalence of malocclusions in the Shiraz orthodontic population, we studied the records of 700 patients (391 girls and 309 boys) aged 6-14 years attending the undergraduate Department of Orthodontics at Shiraz University of Medical Sciences. The prevalence of Angle class I, II and III malocclusion of first molars was 52.0%, 32.6% and 12.3% respectively. Skeletal class I, II and III malocclusion was found in 18.0%, 70.0% and 12.0% respectively. There were no significant differences between the sexes in the prevalence of different types of skeletal malocclusion. Children with class III were significantly younger (mean age 8.9 years) than those with class I (9.6 years) or class II (9.7 years) malocclusions. Orthodontics students need more education and training in the management of class II malocclusion to improve the overall quality of care for patients.

Introduction: Each facial feature might affect the perception of the balance of the other features so the whole of the face must be considered in facial evaluation. There are no studies that have examined the effect of forehead and neck position on profile esthetics. The objective of this study was to evaluate the effects of forehead and neck positions on profile esthetics judged by lay people, dental students and art students., Materials and Methods: A straight silhouette (black right-facing profile in white background) was digitally manipulated to make variations of profiles. The positions of all compartments of face were similar except for anteroposterior position of forehead and neck. The 310 raters (100 dental students, 100 art students and 110 lay people) were asked to rate profiles with a Likert scale. The nonparametric Mann-Whitney test, chisquare tests, Spearman rank correlation coefficients, one-way analysis of variance (ANOVA) and Kruskal-Wallis analyses were used in data analysis., Results: The scores given to profiles with straight, retruded and protruded necks and foreheads were significantly different. (P < 0.05). In three groups, the most and least attractive profiles judged by raters were comparable (P > 0.05)., Conclusion: This study showed that the position of the forehead and the neck has an effect on the beauty of profile silhouettes and this effect is so noticeable that all of the raters could perceive the differences. It is necessary to evaluate the whole of the face, including the forehead and neck, in a facial evaluation.

Background: Curved roots of teeth might cause difficulty in root canal treatment and removal. Beside genetic factors, root morphology of the third molars is affected by environmental factors such as mesial migration. However no studies examine the relation between the amount of third molars' movement and their root angles. The purpose of this study was to evaluate the relation between the amount of third molar movement during orthodontic treatment and the angulation of third molar roots., Materials and Methods: The records of 39 patients who had apical closure after orthodontic treatment were evaluated. Root curvature was measured on panoramics using the angle between an occlusal reference line and central line of the most apical ninth of the root. The amount of tooth movement of third molars was measured on the pre- and post- treatment lateral cephalometric radiographs by measuring tooth distance from a perpendicular line. Pearson correlation analysis was preformed to obtain relation of the amount of third molar's movement and its root angulation., Results: In maxillary arch the correlation between tooth movement and root angulation was positive and not significant relation but in mandibular arch this relation was negative and not significant. ( P > 0.05) CONCLUSION: The relation between the amount of third molar movement and its root angulation was not statistically significant. Therefore movement of third molars during orthodontic treatment should not be assumed as an etiologic factor of root angulations.

Purpose: Many geometric forms and mathematical functions have been proposed as models of the dental arch; however, no such information seems to be available for the primary dentition. The purpose of this study was to develop a model for dental arch form in the primary dentition., Methods: The participants were 92 children (47 boys, 45 girls) in primary dentition. Dental casts were used to measure dental arch dimensions with digital calipers. The arch form was classified as round, long, and short. The values of A and B in the polynomial function formula Y=Ax(m) + Bx(n) were calculated so that the curve would pass through all teeth in the arch. Data were analyzed and compared with the independent t-test and multiple regression analysis., Results: There was significant difference between boys and girls in dental arch widths (P=0.025) and depths at mandibular primary canines (P<0.001) but not significant at the maxillary primary canines (P>.05). The width and depth of the arches at the primary canines correlated significantly with the width and depth at the primary molars (P<0.001)., Conclusions: The sixth-order polynomial function Y=Ax 6 +Bx 2 is a potentially accurate mathematical model of arch form for primary dentition.

Introduction: an attractive smile helps people feel more self-confident and look younger. One of the more controversial aspects of smile attractiveness pertains to buccal corridor size. There is no previous study by those with artistic knowledge that has assessed the asthetic considerations of buccal corridor size. The purpose of this study was to observe whether the size of buccal corridors has an impact on smile attractiveness evaluated by lay people, dental students, and art students., Materials and Methods: colored post-treatment photograph with posed smiles of two subjects (one male, one female) were selected. The maxillary posterior dentitions were digitally altered to produce different buccal corridor sizes: narrow (28% buccal corridor), medium-narrow (22% buccal corridor), medium-broad (10% buccal corridor), and broad (2% buccal corridor). The 5 images of each subject were paired into 11 possible combinations and presented to three group: art students, dental students, and lay people, who compared the two images in each pair of smile attractiveness. The statistical test used were Wilcoxon signed rank and Mann-Whitney test., Results: minimal and excessive buccal corridors were the least attractive when judged by three groups. All groups preferred smaller buccal corridors for the male subject and larger buccal corridors for the female subject. No significant judging differences were found between male and female judges from among art and dental students., Conclusions: minimal or excessive buccal corridor should be included in the problem list during orthodontic diagnosis and treatment planning.

Aim: Orthodontic need assessment is instrumental for dental treatment planning. The objective of this examination was to evaluate the orthodontic treatment need of students in Shiraz, Iran, using the Dental Aesthetic Index (DAI) and to assess the relationship between DAI and sociodemographic variables., Methods: Using random cluster sampling, 1,818 pupils (965 male and 853 female) 14 to 18 years of age without any history of orthodontic treatment were selected. Information was gathered using a questionnaire, including demographics such as sex, family size, and parents' education. Orthodontic assessments were performed by two orthodontists over 2 months. The data were analyzed with chi-square and t tests., Results: Many of the subjects (48.3%) had no need for orthodontic treatment. About one-fifth of the population (21%) had intense-to-disabling malocclusions, and 8.4% had disabling malocclusion with compulsory treatment needs. The study showed a close relationship between sex and malocclusion., Conclusion: The study showed that Iranian youth in Shiraz had better dental appearances and less orthodontic treatment need than some populations (Japanese, Caucasian and Native Americans, and Caucasian Australians) but worse than Chinese, Spanish, and Nigerian populations. It might be possible to relate the difference to genetics, cultural differences, and growth., (© 2011 BY QUINTESSENCE PUBLISHING CO, INC.)