Aim: The propose of this study was to calculate the amount of force that the spring deliver after variable degree of activation. Material & Method: A specific designed program in Pascal language was employed to calculate the forcedelivered by each spring considering relevant variables such as cross section wave length and spring design.Results: The amount of force per each degree activation of 3 different springs currently used in Removable Orthodontic Appliances was calculated. Stainless steel, Z spring with round cross section, 0.5 mm diameter and 1.5 turn helix delivered 45,52,59 gr force when activated at 14, 15, 16 degrees respectively.Conclusion: Useful ranges of force delivery can be achieved with 0.4 mm cross section for finger spring and 0.5 and 0.6 mm for Z-spring.

Aim: This study aimed to compare the incidence of mucosal lesions and pain during Orthodontic treatment with fixed versus Removable Orthodontic Appliances. Methods: This cross-sectional study involved 58 patients with fixed Orthodontic Appliances and 58 patients with Removable Orthodontic Appliances, all aged between 15 and 30 years. The presence and location of lesions were recorded at two time points: two weeks and four weeks after the start of the study. Additionally, the level of pain experienced by the patients was quantified at these same time points using a Visual Analog Scale (VAS). The Chi-square test was used to compare the frequency of oral lesions between the two groups at the onset of treatment. The Kruskal-Wallis test was used to compare the pain score at the onset of treatment between the two groups. The level of significance was set at 0. 05. Results: The frequency of traumatic lesions at two and four weeks was significantly higher in the fixed group (P<0. 050). The frequency of traumatic and allergic lesions increased with time in both groups (P<0. 050). Lichenoid reactions, candidiasis, and exophytic lesions were only detected in the Removable treatment group. At two and four weeks, the frequency of lesions in the buccal mucosa was significantly higher than in other areas in the fixed group (P<0. 050). At four weeks, the pain score of patients was higher in the fixed treatment group (P<0. 050). Conclusion: At four weeks, the frequency of lesions was higher in the fixed group. Buccal mucosa was the most common location of lesions in both groups. Pain in the fixed group was higher than the Removable group at four weeks.

Methods: In this cross-sectional study, 30 children aged between 8-12 years old who were treated with Removable Orthodontic Appliances and 30 healthy children in the same age range as control group were selected. One month after giving instructions on oral hygiene, samples were taken from patients’ oral mucosa. The specimens were assessed by colony formation and germ tube tests. Statistical analysis was performed using Chi-square test with 95% confidence to compare the study groups.Findings: There were significant differences between two groups regarding the redness, soreness, and inflammation which were more frequent in Orthodontic patients (p=0.03). Colony formation was significantly higher in Orthodontic patients than control group (P<0.001). In addition, germ tube was more obvious in samples of Orthodontic patients than control group (P=0.045).Conclusion: Despite the practice of good oral hygiene, application of Removable Orthodontic Appliances leads to an increase in prevalence of Candida albicans.

Background & Aim: The presence of microbial plaque not only can cause unpleasant appearance but it can also cause oral tissue inflammation, malodor as well as digestive system and respiratory tract infection. The aim of this study was to evaluate the efficacy of lemon juice 10% and effervescent cleanser tablet, in removing microbial plaque from the surface of Removable Orthodontic Appliances.Materials & Methods: This study was conducted by using interventional design. Total of 30 patients were randomly selected regardless of their gender status. They were between 9-14 years old (mean age 12) and had maxillary Removable Orthodontic Appliances. Initially, all the Removable Appliances were cleaned thoroughly using ultrasonic device. Patients were instructed to come back in four days. During this period, patients were not allowed to use any kind of mouthwash or other oral hygiene products to clean their Appliances. On the first recall appointment, the Removable Appliances were first placed in Erythrosine solution for 7 minutes and they were scored for the amount of microbial plaque present. These Appliances were rescored after immersing into10% lemon juice solution for 30 minutes. The ultrasonic device was used to clean Appliances before returning them to patients. A 4 day recall visit was scheduled for patients. The same plaque scoring procedure was conducted in the second appointment. This time, the Appliances were immersed in a solution containing effervescent tablet for 30 minutes. This process was repeated two times in order to increase data validity. After completion of data collection, analysis was conducted using Sign Rank test.Results: The plaque scores were decreased in 33 percent of cases (n=10) after using the first method (10% Lemon Juice); but there was no change observed in 66 percent of cases (n=20) (P=0.002). When using the second method (effervescent tablet), although plaque scores slightly decreased in all cases, the complete removal of plaque were observed in 36.6 percent of the patients (n=11) only (P<0.001).Conclusion: The 10% Lemon Juice solution has little effect on reducing the microbial plaque. However, the solution made out of effervescent cleanser tablet is more effective than 10% Lemon Juice solution in removing microbial plaque from Removable Orthodontic Appliances.

Introduction: The use of acrylic Appliances in the oral cavity warrants biocompatibility evaluation. This study aimed to carry out an in vivo investigation of the cytomorphometric changes of oral mucosa among children undergoing acrylic Removable Orthodontic Appliances. Methods: In this observational clinical study, acrylic Removable Orthodontic Appliances were delivered to 25 Orthodontic patients and followed for 3 months. Mucosal samples were collected by gentle brushing of the internal part of the right and left buccal mucosa before appliance delivery (T0) and 1 week (T1), 1 month (T2), and 3 months (T3) following appliance delivery. The cells were immediately prepared for cytomorphometric analysis. Results: There was no significant difference in the nuclear area between different time intervals. Cytoplasmic area in the right side of the buccal mucosa was significantly larger 1 month following appliance delivery (T2), compared to T0 (P=0. 018) and T1 (P=0. 036). On the right side, nuclear to cytoplasmic ratio values in T2 were significantly less than those in T0 (P=0. 008) and T1 (P=0. 002). Moreover, T3 values were lower than T1 values (P=0. 048). The results of micro-nucleation and apoptosis analysis did not show statistically significant differences between different time intervals. Conclusion: Orthodontic acrylic Appliances may not be a factor in inducing morphologic changes of oral mucosa cells,nevertheless, they may promote some transient cytometric effects. It seems that they do not cause any significant damages to the oral mucosa in long term.

Background and Aim: Orthodontic Appliances can impair the balance of oral microflora and increase the load of certain microorganisms in the oral cavity. Chlorhexidine (CHX) is the gold-standard antimicrobial agent for plaque control. However, its long-term use induces adverse effects. The present study seeks to assess the effect of the essential oil of Thymus vulgaris on isolated Candida albicans (C. albicans) from Removable Orthodontic Appliances. Materials and Methods: In this study, thirty-two dental students were requested to use Removable Orthodontic Appliances for 7 days. Subsequently, the acrylic base of the appliance was checked for the isolation of C. albicans. Furthermore, the effect of Thymus Vulgaris essential oil on isolated C. albicans were evaluated using the disc diffusion method, and then its minimum inhibitory concentration (MIC) was determined. Results: The results of this study indicated that the essential oil of Thymus vulgaris was significantly more effective than CHX in the elimination of isolated C. albicans from the surface of Orthodontic Appliances (P<0. 05). Moreover, its MIC was calculated to be 15. 6 μ L/mL. Conclusion: The essential oil of Thymus vulgaris has favorable antimicrobial activity against C. albicans greater than that of CHX.

Aim: This study aimed to compare the treatment progress and complications between patients receiving conventional Orthodontic treatment and clear aligners during the coronavirus disease-2019 (COVID-19) pandemic.Methods: An electronic survey was distributed randomly among Orthodontic patients in Saudi Arabia to understand how the global health crisis caused by COVID-19 affected Orthodontic patients. The survey questions were structured into four sections, including demographic data, continuation of Orthodontic follow-up appointments during the COVID-19, reasons for missed appointments, and problems of Orthodontic patients. Data analysis consisted of simple descriptive statistics presented in frequency tables and percentages. Statistical significance was set at P≤0.05.Results: A total of 512 electronic responses were received. Sixty-two (12.11%) participants missed no Orthodontic follow-up appointment during the COVID-19 lockdown. Hence, the study included 450 (87.89%) participants to evaluate the impact of COVID-19 pandemic on sustained Orthodontic treatment.The proportion of patients in the fixed appliance group (35.2%, 86 patients) who responded that “they had not even once tried to communicate with their orthodontists” was significantly higher than that in the clear aligner group (9.2%, 19 patients) (P<0.001). The proportion of participants who received fixed Appliances (62.3%, 152 patients) and disagreed with the lockdown of Orthodontic clinics during the COVID-19 was significantly higher than that in clear aligner users (19.4%, 40 patients) (P<0.001).Conclusion: The results indicated that most issues were reported by patients who had fixed Appliances. Thus, tele-Orthodontics could provide a solution to continue dental practice during the COVID-19, and clear aligners are preferable to traditional Orthodontic treatment methods.