Introduction: Many patients seeking orthodontic treatment already have incipient enamel lesions and should be placed under preventive treatments. The aim of this in vitro study was to evaluate the effect of CPP-ACP paste and CO2 laser irradiation on demineralized enamel microhardness and shear bond strength of orthodontic brackets. Methods: Eighty caries-free human premolars were subjected to a demineralization challenge using Streptococcus mutans. After demineralization, the samples were randomly divided into five equal experimental groups: Group 1 (control), the brackets were bonded without any surface treatment; Group 2, the enamel surfaces were treated with CPP-ACP paste for 4 minutes before bonding; Group 3, the teeth were irradiated with CO2 laser beams at a wavelength of 10.6 µm for 20 seconds. The samples in Groups 4 and 5 were treated with CO2 laser either before or through CPP-ACP application. SEM photomicrographs of a tooth from each group were taken to observe the enamel surface. The brackets were bonded to the buccal enamel using a conventional method. Shear bond strength of brackets and ARI scores were measured. Vickers microhardness was measured on the non-bonded enamel surface. Data were analyzed with ANOVA and Tukey test at the p< 0.05 level. Results: The mean shear bond strength and microhardness of the laser group were higher than those in the control group and this difference was statistically significant (p< 0.05). All groups showed a higher percentage of ARI score 4. Conclusion: CO2 laser at a wavelength of 10.6 µm significantly increased demineralized enamel microhardness and enhanced bonding to demineralized enamel.

Objectives Orthodontic patients around the world had to miss appointments during the early months of the COVID-19 pandemic. A significant problem with this virus is its high transmission power. Asymptomatic patients can transmit the virus. This aim of this review is to examine orthodontic emergency situations and the necessary strategies and measures for emergency and non-emergency during the coronavirus pandemic. Methods The following databases were comprehensively searched: PubMed, MEDLINE, Scopus, and Google Scholar. Up-to-date data released by major health organizations such as WHO and major orthodontic associations involved in the pandemic were also evaluated. Results Few studies are conducted on how to manage orthodontic offices or clinics during the pandemic and mostly are not of high quality. Appropriate communication is the most important issue in managing orthodontic patients, particularly virtual counseling. Many cases of orthodontic emergencies can be managed in this way by patients themselves. Most studies recommend using the FFP2 masks, equivalent to N95 masks for non-COVID-19 cases undergoing aerosol-generating procedures and all suspected or confirmed COVID-19 cases in orthodontic visits. Conclusions At this time, there are no definitive clinical protocols supported by robust evidence for orthodontic practice during COVID-19 pandemic. Orthodontists should not rush to return to routine orthodontic work and should follow state guidelines. Non-emergency orthodontic visits should be suspended during the SARS-CoV-2 pandemic in high-risk areas. Resuming orthodontic procedures during the pandemic requires paying special attention to screening, performing maximum efforts to reduce aerosol, appropriate PPE, proper ventilation, and full adherence to sterilization and disinfection principles.

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Introduction: Various systems for intraoral digital radiography have been available as an alternative to film-based radiography. In consideration of several advantages of digital radiography such as less patient absorbed dose, manipulation of image quality and elimination of processing, it has been extensively used in different fields of dentistry in recent years. The purpose of this study was comparison of conventional film and digital radiography in the proximal caries diagnosis. Materials and Methods: In this in vitro study, 60 extracted premolar teeth were selected and mounted in acrylic blocks. The teeth were radiographed using F-speed film and a complementary metal oxide semiconductor digital sensor (CMOS). Two observers evaluated interproximal surfaces for detection of presence and extent of caries. True caries depth was determined by histological examination. The diagnostic accuracy of each radiographic system were assessed by means of receiver operating characteristic curve (ROC) analysis. Results: There was no significant difference between two imaging modalities. The AZ values in cases without caries and dentinal caries were greater than caries restricted to enamel and Dentino Enamel Junction (DEJ). The differences among observers also were not statistically significant. Conclusion: Both imaging modalities were comparable in the detection of proximal carious lesions.

Objectives: Considering the changes in periodontal parameters after orthodontic treatment and lack of adequate evidence on the return of these parameters to normal, the aim of this study was to evaluate the time needed for recovery of periodontal parameters to normal after debonding. Methods: In this prospective study, 24 patients (21 females and 3 males) with a mean age of 18.86 ± 4.64 years were included, who were in the final stage of their orthodontic treatment and ready for debonding of orthodontic brackets. The most important inclusion criteria were: No history of periodontal problems, no extensive restorations and caries, no smoking, no systemic disorders and no calculus. In each session, the patients were given oral health instructions and then probing depth (PD), plaque index (PI), gingival index (GI) and bleeding on probing (BOP) of the first molars and central incisors of each quadrant were evaluated at the time of debonding (T1), and one (T2), two (T3) and three (T4) months later; in patients who did not return to normal status (GI ≤ 0.5, negative BOP, PD ≤ 3 mm) after 3 months, the measurements were repeated in subsequent months (up to 6 months). ANOVA followed by pairwise Tukey comparisons were used for determining differences in PD, GI, BOP and PI between the time intervals. Results: In general, all the parameters were decreased from T1 to T4. Furthermore, comparisons between different intervals using post hoc Tukey test showed that decreases in PD of the buccal surface and proximal surface in comparison to debonding time were significant during the first and second months, respectively (P < 0.05). Interpretation of statistical data showed a significant reduction in GI after two months. BOP became negative and significantly different after one month in half of the teeth and two months in the other teeth. PI generally decreased from T1 to T4. Conclusions: Based on the results of this study, periodontal parameters returned to normal one to two months after debonding.