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Background: Interclinoid ligament calcification and dimensional changes in Sella Turcica seen on cephalometric radiographs are associated with some bone abnormalities as well as normal variations. Merging of anterior and posterior clinoid processes, known as Sella Turcica bridging or roofing and other changes in this area may occur as a part of large skeletal growth changes in body and may have association with craniofacial skeletal patterns development.

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. 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. 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. 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. The VFR might be a good alternative for HR due to its better esthetic appearance and greater popularity with orthodontic patients. American Board of Orthodontics model grading system, American Board of Orthodontics objective frading system, Gingival index, Hawley retainers, Vacuum-formed retainers.

Background: Maintaining the results of orthodontic treatment and keeping the teeth in the corrected position is a great challenge in orthodontics. This study aimed to compare the survival time of three types of retainers including Hawley, 1-mm Vacuum-Formed (VF), and 1.5mm VF within 6-month period. Methods: In this randomized clinical study, 152 patients were allocated into three groups to receive one type of the retainers. They were visited 1, 3, and 6 months after retainer delivery and checked for breakage, loss, local perforation, and discoloration from the patient's and clinician's point of view as indicators of failure. Chi-square and Fisher's exact tests were used as appropriated. Result: The results revealed that breakage was among the main reasons of failure of retainers within 6 months, which was statistically significantly different between Hawley and VF retainers, as well as between 1-mm and 1.5-mm VF retainers in the three intervals (p<0.05). Concerning the loss of retainer and discoloration from the clinician's point of view, there was no significant difference between the retainers in any interval (p>0.05). Assessing the discoloration from the patient's point of view revealed statistically significant differences between Hawley and VF retainers within the first month; however, the difference was not significant at the third and sixth months (p<0.05). The difference between the two thicknesses of VF retainer was not significant in any interval (p>0.05). By the end of the sixth month, some of the VF retainers had perforation; while, perforation was not observed in Hawley retainers. Conclusion: Considering the higher breakage rate of 1-mm VF, 1.5-mm VF seems the retainer if choice.

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.