Er,Cr:YSGG Laser as a Means of Orthodontic Adhesive Removal: Myth or Reality?

Objective: This study aimed to compare the effect of Er,Cr:YSGG laser with a tungsten carbide bur in orthodontic finishing on the enamel surface roughness and the heat generated in the pulp chamber. Methods: Before bonding, of 125 intact extracted premolar teeth, 15 teeth were randomly assigned to the control group. Of the remaining 110 bonded teeth, 50 were used to determine the laser parameters, and 60 were included in the main in vitro study. After debonding, the teeth were randomly distributed among four study groups (n = 15) for finishing with laser beams (Er,Cr:YSGG, Waterlase) with and without polishing with Sof-Lex discs, and finishing with a bur (tungsten carbide, Reliance) with and without polishing with Sof-Lex discs. The thermal changes were measured during finishing using a thermo-controller-coupled thermocouple placed in the pulp chamber. Enamel surface roughness was evaluated qualitatively under a scanning electron microscope (SEM) and quantitatively under an atomic force microscope (AFM). Results: The thermal changes of the bur group were significantly higher than those in the laser group (p = 0.0001). Quantitatively, the surface roughness values of all the study groups were significantly higher than those of the control group (p < 0.05), with no significant difference between the study groups (p > 0.05). SEM analysis confirmed the AFM measurements. Conclusions: Er,Cr:YSGG can be recommended as an alternative for a carbide bur for adhesive agent removal after orthodontic debonding, considering its mild thermal effect on the pulp. Polishing with Sof-Lex discs did not significantly reduce the surface roughness, regardless of the finishing procedure.

Photogrammetric Comparison of Facial Soft Tissue Profile before and after Protraction Facemask Therapy in Class III Children (6-11 Years Old).

STATEMENT OF THE PROBLEM: Achieving a normal soft tissue facial profile is considered to be the main concern of class III patients and the goal of most class III treatments. PURPOSE: The purpose of this study was to investigate the effects of facemask treatment on profile with photogrammetric method. MATERIALS AND METHOD: Before (T0) and after (T1) treatment photograms of 40 class III patients profiles (20 male and 20 female individuals) treated with protraction face mask that met the inclusion criteria were digitized and analyzed using Aesthetic Analyzer software. Selected linear and angular measurements were performed for each patient and the changes were noted. RESULTS: An increase in inferior facial height (p< 0.001) and inferior facial angle (p< 0.001) was observed. Nasal prominence and upper lip prominence also increased significantly (p< 0.001). Advancement of sub nasal area was observed to be significant in females (p< 0.05) in contrast to males. CONCLUSION: Remarkable advancement in the middle face and consequent fullness in the soft-tissue profile can be achieved by using protraction face mask. The response to treatment is not different between males and females.

The Effect of Four Surface Treatment Methods on the Shear Bond Strength of Metallic Brackets to the Fluorosed Enamel.

STATEMENT OF THE PROBLEM: Some studies have reported the bond strength to be significantly lower in fluorotic enamels than the non-fluorosed. PURPOSE: The purpose of this study was to evaluate the shear bond streongth of metallic brackets to non-fluorosed and fluorosed teeth after different enamel conditioning. MATERIALS AND METHOD: A total of 176 freshly extracted human premolars (88 non-fluorosed and 88 fluorosed teeth) were used in this study for bonding the metallic brackets. Teeth with moderate fluorosis were used according to Thylstrup and Fejereskov index (TFI). Eighty non-fluorosed and 80 fluorosed teeth (TFI=4-6) were randomly divided into 8 equal groups of 20 teeth each. The remaining 16 teeth were used for scanning electron microscopy observation. The enamel surface was conditioned by 4 methods: acid etching  for 30 sec, acid etching for 120 sec, air abrasion followed by acid etching, and Er: YAG laser etching followed by acid etching. The morphology of etching patterns in different groups was studied under scanning electron microscope. RESULTS: The shear bond strength of fluorosed teeth to the brackets was significantly lower than non-fluorosed ones (p= 0.003). The shear bond strength of laser-acid groups in both non-fluorosed and fluorosed teeth was significantly lower than other groups (p< 0.001). Weibull analysis indicated that the chance of failure under the applied force was different between fluorosed and non-fluorosed group. The scanning electron microscope observations revealed that the fluorosed teeth treated with phosphoric acid had fewer irregularities compared to non-fluorosed teeth. The most irregularities were detected in the teeth conditioned with phosphoric acid for 120 seconds. CONCLUSION: Fluorotic enamel adversely affects the bond strength of orthodontic brackets. None of the conditioning methods tested in this study could significantly improve shear bond strength of metallic brackets. Er: YAG laser conditioning followed by acid further reduced the bond strength in non-fluorosed and fluorosed teeth.

Photographic Facial Soft Tissue Analysis by Means of Linear and Angular Measurements in an Adolescent Persian Population.

OBJECTIVE: To obtain objective average measurements of the profile and frontal facial soft tissue to be used as a guide for aesthetic treatment goals. Methods and Materials : This observational study included 110 females and 130 males high school students aged 16-18 years. None of the subjects had any facial deformities. All of them and their parents gave consent to take part in this study. In each case, two standard photographs of profile and frontal views were taken 27 landmarks were digitized on photographs. The mean, standard deviation, and range for a total of 43 facial indices were calculated digitally by computer software. The Student's t-test was used to compare males and females. Results : The ratio between the lower and middle facial thirds was one to one, but the height of the upper facial third was proportionally smaller than the other two-thirds in both sexes. Boys had greater nasal length, depth, and prominence than girls with statistically significant differences. Both upper and lower lips were more prominent in girls than in boys. All measurements of the chin showed sexual dimorphism characterized by greater chin height and prominence and deeper mentolabial sulcus. Boys had greater facial dimensions than girls. Mouth width, nasal base width, and intercanthal distance were significantly greater in boys. Conclusion : The labial, nasal, and chin areas showed sexual dimorphism in most of the parameters used in this study. Boys had larger faces, greater facial heights, longer nasal, labial, and chin lengths, and greater nasal, labial, and chin prominence.

Utilization of Orthodontic Services in the Fars Province, Iran: The Reasons People Travel to the Capital for Orthodontic Treatment.

STATEMENT OF THE PROBLEM: The first step towards appropriately planning orthodontic treatment and prevention services is to understand the needs and demands of the target population. However, this is ignored in most developing countries. PURPOSE: This study aims to evaluate the attitudes of patients in Fars province towards travelling to the provincial capital (Shiraz) to receive orthodontic treatments. MATERIALS AND METHOD: This cross-sectional study randomly selected 420 patients referring to two public and four private orthodontic centers in Shiraz, coming from other regions of Fars province. The patients were interviewed about their demographic status, residing area and the reasons of deciding to receive orthodontic treatment in Shiraz. Data were analyzed by SPSS software, using Chi-square and ANOVA statistical tests. RESULTS: The response rate was 96% (N=403). Near half of the patients (176; 43.7 %) lived 100-200km, and 80 (19.9%) patients lived farther than 200km from Shiraz. Having no orthodontist (54.8%) and no dentist providing orthodontic treatment (39.2%) in their region were the most important factors bringing the patients to provincial capital for orthodontic treatments. High costs of treatment in their home county and hoping to receive treatment of higher quality were the other important motives for lower and higher socio-economic backgrounds, respectively. Friends'/relatives' recommendation was a more important factor in patients using public clinics for choosing their therapist, while referral from dentists was more important for patients going to private clinics. The patients who lived in counties farther than 200km from Shiraz were more concerned about quality of treatment results than those who lived closer (p= 0.010). CONCLUSION: A multifactorial approach is needed to provide the desired orthodontic services for people in Fars province so that they would not need to travel to the capital for such treatments.

The public attitude towards selecting dental health centers.

STATEMENT OF THE PROBLEM: No published literature was found studying the people's reasons on why to choose or not to choose a dental care setting in south Iran, while understanding their attitude towards choosing their dental care center is consequential for planning a successful oral health care service system.    PURPOSE: To determine the factors affecting how people of the city of Shiraz choose their dental health services. MATERIALS AND METHOD: A cross-sectional analytic study was designed. A self-administered questionnaire was produced, tested and then distributed among 570 multistage randomly selected parents of schoolchildren of the city of Shiraz. Independent t-test, paired t-test and Spearman correlation were used to analyze the factors influencing participants in choosing clinics for their esthetic and non-esthetic dental treatments. RESULTS: 400 questionnaires were complete and analyzed. The recommendation from others was found to be the most encouraging factor to choose a dentist or a dental clinic. More importance was reported for various factors affecting participants' choice of dental clinic when seeking non-esthetic treatments, while recommendation and reputation of dentist/dental clinic played a vital role in esthetic treatments. The cost was more important for respondents living in more deprived districts (p= 0.05), for unemployed group (p< 0.001) and for those with less education (p< 0.001). CONCLUSION: Factors affecting people's choice for dental care proved to be highly complicated. Recommendation was found playing an important role. Dental patients consider various factors when looking for non-esthetic treatment but would go for the best possible when seeking esthetic treatments. Findings of this study indicate that patients' choice and utilization of dental service can be improved if dental clinics provide high quality of dental care with reasonable fees.

Tooth eruption sequence and dental crowding: a case-control study.

UNLABELLED: When cases of dental crowding are identified and diagnosed promptly, interceptive orthodontics is particularly successful. AIM: To assess the differences in the eruption sequence of the mandibular canine and first premolar teeth in children with and without dental crowding. MATERIALS AND METHODS: Children who attended the Shiraz Dental School's orthodontic clinic (Iran) from September to December 2012 were enrolled in this case-control study. Tooth size arch length discrepancy (TSALD) of all 8-10 year olds was calculated from patients' dental models. Thirty-six children were randomly selected from those with TSALD of equal or less than 4mm (those with crowding). Each selected case was matched for sex and age with another child (as control) with TSALD>-4mm attending the same clinic, in the same time period. The existing panoramic radiographs were traced and the eruption percentages were measured for mandibular canine and first premolar teeth. The mean difference between canine and first premolar eruption percentages was compared between the case and control groups using the SPSS (version PASW 18) software and a paired sample t-test. RESULTS: Canine and first premolar eruption percentages in the case group were 65.82±13.00 and 78.92±10.15 percent, respectively. The mean eruption percentages for canines and first premolars of the control group were 74.12±14.55 and 75.47±11.60 percent, respectively. There was a significant difference in pre-eruptive positions of canine and first premolar teeth in those with moderate to severe crowding when compared to the control group (p<0.001). CONCLUSION: These findings may improve the early diagnosis of children with high risk of developing moderate to severe crowding during mixed dentition.