Evaluation of the bisphenol released in the saliva after residual adhesive removal in orthodontic patients by using ultrasonic scaling and rotary system: A single-center randomized clinical trial.

INTRODUCTION: Bisphenol A (BPA) is a substance commonly used in dental materials with noxious properties. Monomers of this substance may be dissolved in the saliva and cause adverse effects. This study aimed to evaluate the amount of BPA released in the saliva after residual adhesive removal in orthodontic patients using an ultrasonic scaler (US) and tungsten carbide bur (TCB). METHODS: This single-center randomized clinical trial was conducted on 40 subjects whose stainless-steel brackets were bonded directly with light-cured bonding and composite. The subjects were randomly divided into 2 equal groups (n = 20) of TCB or US according to the adhesive removal method. The salivary BPA level was determined using high-performance liquid chromatography-mass spectrometry. And adhesive cleaning time was measured by a stopwatch. Data were analyzed by SPSS using an independent t test and paired-samples t test (P <0.05). RESULTS: The mean salivary BPA level was significantly lower in the TCB method than in the US method. (1.008 ± 0.061 µg/mL and 2.83 ± 0.24 µg/mL, respectively) (P <0.001). The mean adhesive cleanup time was significantly shorter in the TCB method than in the US method (8.86 ± 0.83 minutes and 13.20±1.02 minutes, respectively) (P <0.001). CONCLUSIONS: According to the results, residual adhesive removal with TCB released less BPA in saliva and shortened the adhesive cleaning time than the US method. TRIAL REGISTRATION: The trial was registered at the Iranian Registry of Clinical Trials (IRCT20200702047988N1). PROTOCOL: The protocol was not published before trial commencement.

Evaluation of the epithelial cells of lower lip mucosa after debonding of fixed orthodontic appliances.

BACKGROUND: Orthodontic appliances (ligatures, braces, wires, etc.), are one of the main sources of trauma in the oral cavity. Friction between brackets and mucosa is a kind of chronic trauma that may cause buccal mucosal proliferation and ulceration and is one of the most common complaints of patients during orthodontic treatment. The aim of this study was to evaluate the changes of the lower lip epithelial cells after the removal of orthodontic fixed appliances. METHODS: Cells of lower lip oral mucosa of 31 orthodontic patients were collected by exfoliative cytology in three times: immediately (T0), 30(T1) and 60 (T2) days after debonding. Nuclear (NA) and cytoplasmic (CA) areas, NA/CA ratio, cell morphology and cellularity of smears were evaluated using cytomorphometric and cytomorphologic methods. Friedman test followed by the Wilcoxon test was used to compare the NA, CA and NA/CA values in three different times. Cell morphology and cellularity were analyzed by the Chi-square test. All statistical tests were performed with SPSS version 20. RESULTS: The NA and CA values increased significantly (P<0.001) after the removal of friction and irritation of orthodontic appliances in T1 and T2 and reached their highest level in T2. The NA/CA values did not change significantly (P=0.25). Class I smears, according to Papanicolaou classification, were observed in T0, T1, and T2. Superficial epithelial cells were predominant cell types in the lower incisor region in all times without statistically significant difference in three intervals. CONCLUSIONS: Orthodontic appliances increase keratinization of lip mucosa which is considered an adaptive reaction to the mechanical stimulus, but after removing of the appliances cellular activity rapidly increases. Keratinization is the main change observed at the end of orthodontic treatment.

Patient-centered evaluation of alignment changes during the first stage of orthodontic treatment: A longitudinal observational study.

Background . The aim of this longitudinal observational study was to evaluate patients' perceptions of alignment changes during the first stage of fixed orthodontic treatment. Methods . Ninety-three non-extraction patients (mean age: 17.6 years) who were scheduled to undergo fixed-appliance treatment in the first author's private office were included. Patients assessed the alignment of their teeth subjectively using visual analogue scale at the bonding session and four, eight and 12 weeks later. The amount of Little's irregularity index at each session was calculated on stone casts. Freidman test was used to compare the "alignment changes" between different intervals. Correlation coefficients were calculated using Spearman test between Little's irregularity indices and alignment scores reported by the patients in each session. Results . No patients reported regression in alignment changes during three-month course of treatment. The final changes (from bonding session to the 12th-week visit) were smaller than the sum of the three intervals, which indicated that patients became more perceptive as the treatment progressed. Comparison of two scores reported for each session (in the same session and in the next session) revealed that patients could not recall their previous situation well. Patients do not perceive alignment changes in the same way as clinicians. Furthermore, patients who were 16 or older perceived smaller alignment changes during the first four-week period and smaller final alignment changes. Conclusion . To obtain better patient compliance and improve their motivation throughout orthodontic treatment, patientspecific measures should be undertaken, including reminding them about their initial conditions and highlighting the changes as the treatment progresses.

Comparison of Stability of the Results of Orthodontic Treatment and Gingival Health between Hawley and Vacuum-formed Retainers.

Aim: Retention is one of the stages of orthodontic treatment, which is an attempt to retain teeth in their corrected positions after active treatment with the use of fixed orthodontic appliances. The aim of the present study was to compare the stability of the results of orthodontic treatment and the gingival health between Hawley retainer (HR) and vacuum-formed retainer (VFR) with two different thicknesses. Materials and methods: In this randomized clinical trial, 66 patients undergoing comprehensive orthodontic treatment in a private office were evaluated after completion of treatment. The subjects were randomly assigned to three groups. At the end of orthodontic treatment, the subjects in all the groups received a fixed bonded retainer in the mandible; in the maxilla, group I received an HR, group II received a VFR with a thickness of 1.5 mm, and group III received a VFR with a thickness of 1 mm. The American Board of Orthodontics objective grading system (ABO-OGS) index was used at the end of treatment (before the delivery of the retainers) and 6 months after the use of retainers to evaluate the stability of the results of orthodontic treatment. Gingival index (GI) was used at the two above-mentioned intervals to evaluate gingival health. The ABO-OGS measurements were carried out on dental casts by a clinician who was blinded to the types of retainers the patients wore. Data were analyzed with Statistical Package for the Social Sciences (SPSS) version 20, using proper statistical analyses. Results: Six months after the delivery of retainers, ABO-OGS and GI scores with the 1.5 mm VFR were higher than those in the two other groups, with no significant differences between the three groups. There were no significant differences between the ABO-OGS scores before the delivery of retainers and 6 months after the use of retainers in any of the study groups. In the HR and 1.5 mm VFR groups, there were significant differences in GI scores between the period before the delivery of the retainers and 6 months after their delivery; however, in the 1 mm VFR group, no significant differences were observed in GI scores between the two time intervals. Conclusion: Hawley retainer and 1 mm thick and 1.5 mm thick VFRs were equally effective in preserving and stabilizing the results of orthodontic treatment during the 6-month interval after the completion of orthodontic treatment. In addition, there were no significant differences between the three retainers in relation to gingival health. Clinical significance: The VFR might be a good alternative for HR due to its better esthetic appearance and greater popularity with orthodontic patients. Keywords: American Board of Orthodontics model grading system, American Board of Orthodontics objective frading system, Gingival index, Hawley retainers, Vacuum-formed retainers.

Evaluation of Interdental Spaces of the Mandibular Posterior Area for Orthodontic Mini-Implants with Cone-Beam Computed Tomography.

INTRODUCTION: The use of mini-implants has increased in recent years because of their role in absolute anchorage, but the placement sites may affect the success or failure of the procedure, so it is very important to determine the appropriate and safe location for orthodontic mini-implants. On the other hand, the Cone Beam Computed Tomography (CBCT), which offers clear 3-Dimentional (3D) images, has been widely used in orthodontics and implant dentistry for surgical guidance of mini-implant placement. AIM: The aim of this retrospective study was to evaluate inter-radicular spaces between mandibular canines to second molars using cone beam 3D images. MATERIALS AND METHODS: In this retrospective cross-sectional descriptive study, maxillofacial CBCT scan data were obtained from 40 adults. The 3D images were evaluated in five axial sections at 2, 4, 6, 8 and 10 mm from the cementoenamel Junction (CEJ). To determine inter-radicular spaces, tangent lines were drawn buccolingually to the roots in axial section and the minimum distance between these two lines was measured. The data was analysed using Friedman test with SPSS(ver.13). RESULTS: Interradicular spaces of canine to second molar increased from cervical to apical direction. The maximum distance was recorded at 4 mm from the CEJ between first and second molars. CONCLUSION: According to our findings there is a distinct pattern of inter-radicular space changes in mandible. Attention to this pattern during placement of mini-implants can ensure the safety of the procedure.

The reliability of clinical decisions based on the cervical vertebrae maturation staging method.

OBJECTIVES: Of the various techniques used to determine the optimum timing for growth modification treatments, the cervical vertebrae maturation method has great advantages, including validity and no need for extra X-ray exposure. Recently, the reproducibility of this method has been questioned. The aim of this study was to investigate the cause of poor reproducibility of this method and to assess the reproducibility of the clinical decisions made based on it. MATERIALS/METHODS: Seventy lateral cephalograms of Iranian patients aged 9‒15 years were observed twice by five experienced orthodontists. In addition to determining the developmental stage, each single parameter involved in this method was assessed in terms of inter- and intra-observer reproducibility. In order to evaluate the reproducibility of clinical decisions based on this method, cervical vertebrae maturation staging (CVMS) I and II were considered as phase 1 and CVMS IV and V were considered as phase 3. RESULTS: By considering the clinical approach of the CVMS method, inter-observer reproducibility of this method increased from 0.48 to 0.61 (moderate to substantial) and intra-observer reproducibility enhanced from 0.72 to 0.74. LIMITATIONS: 1. Complete visualization of the first four cervical vertebrae was an inclusion criterion, which also limits the clinical application of CVMS method. 2. These results can be generalized when determining growth modification treatments solely for Class II patients. CONCLUSIONS: Difficulty in determining the morphology of C3 and C4 leads to poor reproducibility of the CVMS method. Despite this, it has acceptable reproducibility in determining the timing of functional treatment for Class II patients.

Awareness of Orthodontic Treatments among School Teachers of Two Cities in Iran.

BACKGROUND AND AIMS: Since most orthodontic patients are children and adolescents, it is believed that teachers can help find these patients and make them aware of their orthodontic problems. Therefore, teachers are expected to have proper knowledge about these problems. The aim of this study was to determine teachers' awareness about orthodontic treatments in Tabriz and Saqqez and compare it in different educational levels. MATERIALS AND METHODS: A questionnaire was given to 384 teachers (204 in Tabriz and 180 in Saqqez) in randomly selected schools of different levels. The questionnaire had 17 questions in 3 sections, including general information, age, and costs of orthodontic treatments. The teachers' awareness in two cities was analyzed with independent t-test and in edu-cational levels with one-way ANOVA. RESULTS: About 94% of the participants believed orthodontic treatment consisted of arrangement of teeth with special braces. However, there was no significant difference between the two cities in general information (p=0.23) and the age suitable for orthodontic treatment (p=0.53). The differences in the teachers' awareness in three educational levels were not statistically significant between the two cities (p=0.23). CONCLUSION: Awareness of teachers about orthodontic treatment in Saqqez and Tabriz was not sufficient and different; 75% of the participants believed that high cost of orthodontic treatment is the main problem.

Comparison of the effect of hydrogel and solution forms of sodium ascorbate on orthodontic bracket-enamel shear bond strength immediately after bleaching: an in vitro study.

AIM: This study compared the effects of hydrogel and solution forms of sodium ascorbate (SA) with two different application times on bracket bond strength subsequent to bleaching. MATERIALS AND METHODS: A total of 72 sound premolars were randomly divided into six groups (n = 12): An unbleached control group (group one) and five experimental groups of carbamide peroxide. Specimens in group two were bonded immediately after bleaching; specimens in groups three and four were bleached, then treated with SA solution for ten minutes and three hours, respectively, and then bonded. In groups five and six, SA hydrogel was used and the specimens were prepared similar to groups three and four, respectively. Following debonding, bond strengths were recorded in MPa. To evaluate the amount of resin left on the enamel surfaces, adhesive remnant index (ARI) scores were used. STATISTICAL ANALYSIS: The bond strength data were analyzed with ANOVA and pairwise comparisons were made by Tukey test. The ARI data were subjected to Kruskal-Wallis test and two-by-two comparisons were made by the Mann-Whitney U test. RESULTS: There were significant differences in bond strengths between the groups ( P < 0.0005). However, the differences between groups three, four, five and six were not significant. Furthermore, there were no significant differences between group one and groups four and six, whereas the differences between the other groups were significant ( P < 0.05). Regarding ARI, there were significant differences among the groups ( P = 0.004). CONCLUSION: Bleaching significantly decreased the bracket bond strength. Compromised bonding was reversed with a three-hour application of both forms of SA.

Components of Adult Class III Malocclusion in an Iranian Population.

BACKGROUND AND AIMS: Class III malocclusions are considered complex and difficult orthodontic problems to diagnose and treat. The purpose of this study was to investigate the morphologic characteristics of the craniofacial complex of adults with Class III malocclusion in an Iranian population. MATERIALS AND METHODS: Lateral cephalometric radiographs of 50 patients with Class III malocclusion (20 males and 30 females; age range of 18-27 years) were selected on the basis of molar relationship, concave profile and an overjet of ≤ 0 mm. The standard values of 19 soft tissue measurements were determined using McNamara, Burstone and Viazis methods. RESULTS: Adults with Class III malocclusion exhibited distinct craniofacial morphologic characteristics manifested by a com-bination of retrusion of maxilla and protrusion of mandible. CONCLUSION: The most prevalent component was mandibular prognathism, normal maxilla and LAFH on the basis of the component analysis.