roozbeh rashed

The Bolton analysis is commonly used by orthodontists. The Bolton ratios of different populations are significantly different from the standard values of Bolton. This study sought to examine the Bolton's anterior and overall ratios in various malocclusion types in Mashhad, Iran, in contrast to the Bolton’s standards.

This descriptive-analytical study was conducted on 240 study models of patients (121 males and 119 females) in four groups (n= 60 cases) of normal occlusion, Class I, Class II, and Class III. The mesiodistal dimensions of the teeth were measured twice using a digital caliper. The anterior and overall ratios of Bolton were calculated. Statistical analysis was conducted utilizing SPSS 18.0.

The mesiodistal width of the maxillary lateral incisors in normal occlusion cases was greater than that in Class I, Class II, and Class III malocclusions (P<0.05). Conversely, the mesiodistal width of the maxillary first and second premolars was the greatest in Class II and the smallest in Class III malocclusion (P<0.05). Correlation was not observed between dental ratios (anterior and overall) and gender or malocclusion groups (P>0.05). Furthermore, the anterior ratio was significantly higher than the Bolton's standard in Class I and III malocclusion groups (P<0.05). The normal occlusion group's overall ratio was significantly lower than the Bolton's original ratio (P<0.05).

Implementing the Bolton analysis in the population of Mashhad, Iran should be approached with caution.

Class II malocclusion is one of the most prevalent occlusion discrepancies. Knowledge of growth changes in craniofacial components can help clinicians plan orthodontic treatment, determine the proper timing to initiate the treatment, and predict the treatment outcome, especially in growth modification protocols. This study evaluates craniofacial skeleton changes in class II malocclusion subjects compared to class I malocclusion. In this cross-sectional study, cephalograms of 858 individuals aged between 7 and 23 were investigated. The samples were divided into the class I group (ANB angle 0–4) and class II group (ANB angle ≥ 4 degrees), including 426 and 432 cephalograms, respectively, and each group was divided into seven subgroups considering age. Cephalometric analysis was performed using OnyxCeph software, and statistical analyses of variance, mean, paired t test, and independent samples t test were performed using SPSS software. The results showed no significant differences between class I and class II groups in variables related to the cranial base and vertical facial height. In class II groups, the SNA angle was significantly greater. The total mandibular height (Co-Gn), facial angle (Npog-FH), and SNB angle were significantly greater in class I compared to the class II group. Protrusion of the maxilla affects the formation of class II malocclusion, but an underdeveloped mandible is the main component of Class II malocclusion formation. With increasing age, especially after puberty, the mandible may become more retruded in class II patients.

Knowledge about the factors that play a great role in smile attractiveness of subjects seeking orthodontic treatment helps the orthodontist in treatment planning and deciding to refer patients for adjunctive treatments. The aim of this study was to determine which factors influence smile attractiveness in subjects seeking orthodontic treatment.
In this cross sectional study ,The sample consisted of 45 smile photographs in frontal view belonging to 45 female patients seeking orthodontic treatment and presenting class I, Class II or class III malocclusions. Sixty laypersons (30 males, 30 females) were asked to assess the attractiveness of smile photographs. Each judge was requested to rate the photographs from 0 to 100 using a visual analog scale (VAS). Afterwards, smile images were entered to "Smile Analyzer" software and the amount of incisor show, gingival display, buccal corridor ratio, smile index, philtrum height and commisure height were measured. Finally, the effect of various features on smile attractiveness was analyzed using multiple linear regression analysis.
The linear regression analysis revealed that according to the judgment of males and total female and male raters, philtrum height had a significant influence on smile attractiveness (p value The results of this study indicate that according to the judgment of laypersons, philtrum height and commisure height have significant effects on smile attractiveness of patients seeking orthodontic treatment, so that smile attractiveness was predictably reduced by decreasing philtrum height and increasing commissure height.

This study aimed to find the factors that affect dental esthetics and smile attractiveness in orthodontically treated patients according to laypeople’s judgment, and to determine whether there is any relationship between dental and smile esthetics. Using the Q-sort technique, 60 laypersons (30 males, 30 females) rated dental and smile photographs of 48 orthodontically treated patients based on their degree of attractiveness. Dental and smile parameters of each rated image were measured by Smile Analyzer software. The Student’s t-test and chi-square test were used to compare dental and smile parameters between attractive and unattractive images. The logistic regression was used to assess which variables predicted dental and smile esthetics in treated individuals. The philtral to commissural height ratio and gingival display were significantly different in attractive and unattractive smiles (P=0.003 and P=0.02, respectively). None of the dental variables were found to be a determinant of dental esthetics at the end of the orthodontic treatment (P>0.05). According to the judgment of all raters (female and male) and the male raters’ judgment, smile attractiveness could be predicted by philtral to commissural height ratio and buccal corridor ratio (P<0.05). There was no statistically significant relationship between dental esthetics and smile attractiveness in orthodontically treated patients (P>0.05). The philtral to commissural height ratio and buccal corridor ratio can be considered as predictors of smile attractiveness in orthodontically treated patients. Achieving dental esthetics at the end of orthodontic treatment does not guarantee smile attractiveness.

Elastomeric chains are commonly used in orthodontics. Force decay in these materials poses clinical problems. The aim of this study was to evaluate the effects of three different mouthwashes on the force decay of orthodontic chains. In this experimental study, elastomeric chains with two different confi gurations were divided into eight groups (two control and six test groups). After 10 s of prestretching up to 100% of their initial length, the chains were stretched for 25 mm on jig pins and then immersed in artifi cial saliva, persica, chlorhexidine 0.2% and sodium fl uoride 0.05% mouthwashes. Ten cycles of thermocycling between 5°C and 55°C were conducted daily during the test period. In order to reach a 200-g initial force, seven loop closed chains, and fi ve-loop short chains were selected. Forces were recorded by digital force gauge (Lutron) at initial, 24 h, 1, 2, and 4 weeks for all groups. The amount of force loss was compared among different mouthwashes and times using one-way analysis of variance (post-hoc, Tukey, α = 0.05). About 20% of the force decay occurred during the fi rst 24 h, but after that and up to the 4th week the rate of force loss was gradual and steady. After 4 weeks, persica and chlorhexidine caused the lowest and the highest percentage of force loss, respectively. These two mouthwashes showed statistically signifi cant differences at all points of time (P < 0.05). Within the limitations of this study, during the orthodontic treatment, persica is preferred to chlorhexidine for oral health control.

The objective of this study was to assess the effect of new bonding techniques on enamel surface. Sixty upper central incisors were randomly divided into two equal groups. In the first group, metal brackets were bonded using Trans-bondXT and, in the second group, the same brackets were bonded with Maxcem Elite. The shear bond strength (SBS) of both agents to enamel was measured and the number and length of enamel cracks before bonding, after debonding and after polishing were compared. The number of visible cracks and the adhesive remnant index (ARI) scores in each group were also measured. There were significantly more enamel cracks in the Transbond XT group after debonding and polishing compared to the Maxcem Elite group. There was no significant difference in the length of enamel cracks between the two groups; but, in each group, a significant increase in the length of enamel cracks was noticeable after debonding. Polishing did not cause any statistically significant change in crack length. The SBS of Maxcem Elite was significantly lower than that of Transbond XT (95% confidence interval). Maxcem Elite offers clinically acceptable bond strength and can thus be used as a routine adhesive for orthodontic purposes since it is less likely to damage the enamel.

Anthropometry, a useful method for evaluating craniofacial soft tissues, makes the quantitative description of the face possible. It also assesses the degree of disharmony and imbalance in the growth and development of the face. The aim of this study was to examine the overall common age-related changes of nasomaxillary complex of adolescent boys in northeast Iran. Three- hundred- twelve 12 to 15 year-old boys voluntarily participated in this study. They were divided into three age groups (12-13, 13-14 and 14-15 year-old groups). Digital photographs of the subjects'' faces were taken in Natural Head Position (NHP) frontal and profile views. After determination of the landmarks, nine anthropometric parameters including nasal length, mouth width, alar width, columella width, philtrum height, nasal width, nasolabial angle, nasal root slope angle and nasal index were measured by the Smile Analyzer software considering the magnification ratio of each image. One way ANOVA and Tukey test were used for statistical analyses. Significant differences between the three groups were detected in the mean alar, mouth and philtrum widths, nose length, nasolabial angle and nasal index (P<0.05). We did not find any significant differences in the mean nasal-root-slope angle and the mean philtrum height between the groups (P=0.29 and P=0.13, respectively). Aging of the facial profile is not a gradual process; it occurs in spurts and at different periods of life. During the studied time span, significant growth in nose width and nose length was obvious.

Taking into account the factors related to lip-tooth relationships in orthodontic diagnosis and treatment planning is of prime importance. Manual quantitative analysis of facial parameters on photographs during smile and speech is a difficult and time-consuming job. Since there is no comprehensive and user-friendly software package, we developed a software program called "Smile Analyzer" in the Department of Orthodontics of Mashhad Faculty of Dentistry for measuring the parameters related to lip-tooth relationships and other facial landmarks on the photographs taken during various facial expressions. The software was designed using visual basic. NET and the ADO. NET was used for developing its Microsoft Access database. The program runs on Microsoft Windows. It is capable of analyzing many parameters or variables in many patient's photographs, although 19 more common variables are previously defined as a default list of variables. When all variables are measured or calculated, a report can be generated and saved in either PDF or MS Excel format. Data are readily transferable to statistical software like SPSS for Windows.

Success in endodontic treatment depends on various factors. Among the most important factors, appropriate preparation of the root canal system and keeping periapical region intact as much as possible could be mentioned. These are achieved by determining the penetration depth of the instruments into the canal i.e. the working length. Several methods are introduced for working length determination. The most popular techniques in this regard are the use of conventional radiography and electronic apex locators. A new type of apex locator is the Root ZX. The purpose of this study was to compare the accuracy rate of Root ZX apex locator with the conventional radiography. The working length of thirty extracted single rooted teeth were determined by the means of the Root ZX and conventional radiography then compared with the actual working lengths measured by the stereomicroscope. The results showed there was statistically significant difference between the length determined by the Root ZX and stereomicroscope. In addition, the radiographic and stereomicroscopic working lengths had statistically significant differences as well. There was also significant difference between the lengths measured by the Root ZX and radiography. It is recommended to use the Root ZX and radiography both together to reach the most accurate working length.