Iranian Journal of Orthodontics
Volume:18 Issue: 2, Dec 2023

To evaluate and compare oxygen saturation levels in different facial patterns (average, horizontal, and vertical) existing in different anterior-posterior planes of space (Angle’s Class I, Class II, and Class III) by comparing the amount of hemoglobin bound to oxygen (SPO2) to the total amount of hemoglobin in the blood.

A prospective observational study involving a sample size of 180 adults aged 18–30 was categorized into nine different groups based on their skeletal jaw relationships in the anteroposterior plane occurring in different facial types: average, horizontal, and vertical. The study was conducted using a portable pulse oximetry device (Biosys, BPM-200) to assess the level of saturated hemoglobin in the blood (SPO2).

The mean SPO2 measured was found to be in the range of 95–98%. Comparison between groups showed a statistically significant difference in the mean SPO2 (P=0.002). However, post hoc analysis showed group H had statistical significance.

Based on the analysis of the results obtained from the study, it was concluded that in all facial growth patterns, SPO2 levels were in the normal range. However, the class II skeletal base with a vertical skeletal pattern showed the lowest SPO2 levels. The study also supported the fact that blood oxygen saturation levels are not a concern in any type of facial pattern; hence, no orthodontic intervention as such is indicated to improve their SPO2 levels.

Dental malocclusion and jaw misalignments are the foremost reasons for airway constriction. To facilitate anterior mandibular repositioning and the concomitant anterior positioning of the tongue can induce the expansion of the pharyngeal airway. The study aimed to compare comprehensive treatment outcomes of fixed and removable mandibular advancement appliances on the width of the pharyngeal airway space.

Twenty growing patients with skeletal Class II malocclusion were placed into two groups: Advansync2 and twin block. Patients were advised to use mandibular advancement appliances (MAA) for 9–12 months. Lateral cephalograms and the Epworth Sleepiness Scale (ESS) were evaluated to assess alterations in the pharyngeal airway space and quality of sleep at two intervals. The chi-square test, one-way ANOVA and Duncan’s post hoc test were used for statistical analysis. P-values<0.05 were considered as significant.

Based on the results, only the change in PNS-V measurements indicated a significant difference between appliances. Advansync2 showed more change (0.70±2.45 mm) compared to twin block (-1.80±2.34 mm), indicating a statistically significant difference (p=0.032).

A significant reduction in the ESS score in both groups was observed without any significant differences between them.

Dentistry is a stressful profession, and dental students are susceptible to different forms of stress and psychological pressures. Investigating the amount of this stress and knowing the sources that cause it, can help in creating a supportive and stress-reducing educational environment.

Fifty-nine senior dental students of Tehran Faculty of Dentistry participated in this cross-sectional descriptive study. The data was collected by DASS-21 questionnaire using a 4-scale measure. The total stress scores of the students were calculated at the clinical departments of the Dental School. The severity of depression, anxiety, and stress was calculated for the students. The comparison of the total stress scores at different departments was made by ANOVA, and the effect of demographic factors on predicting the stress scores was determined by linear regression analysis. P-values <0.05 were considered as significant.

Among the total participants, 72.9% (n=43) showed different levels of depression; 57.7% (n=34) had different levels of anxiety and 64.3% (n=38) exhibited different levels of stress. The total stress scores of the students were mostly reported in the endodontics (12.59, P<0.05) and oral medicine (9.2, P<0.05) departments, while the least total scores were found in the orthodontics (3.89, P<0.05) and oral and maxillofacial surgery (4.25, P<0.05) departments.

The senior dental students in Tehran University of Medical Sciences have high levels of depression, anxiety, and stress. The highest levels of stress were related to the departments of endodontics and oral medicine among the educational departments. It appears that dental students living away from their families and the students whose mothers have high educational levels require further support in this respect.

This study evaluated the effect of physical and chemical sterilization techniques on the fracture resistance of mini-implants.

Thirty-two titanium mini-implants of 1.5 x 8 mm were randomly divided into four groups: control, steam sterilized, dry heat sterilized, and chemically sterilized. The samples were then tested in the air for fracture resistance using a universal testing machine. A tangential load was applied to the head of the mini-implant with a 1 mm/min crosshead speed after blocking each of them in the machine. Also, the maximum load was recorded previous to screw fracture. he Kruskal-Wallis test and Mann-Whitney post hoc test were used for data analysis.

The results of this study demonstrated the mean fracture resistance difference between the four groups was statistically significant at p<0.001. Moreover it was showed the control group had significantly higher mean fracture resistance compared to dry heat and chemically sterilized groups at p=0.001 and p=0.009 respectively. This was followed by the stem sterilized group demonstrating significantly higher mean fracture resistance as compared to dry heat and chemically sterilized groups at p=0.001 and p=0.01 respectively. Later, the chemically sterilized group also showed significantly higher mean fracture resistance as compared to the dry heat group at p=0.002. However, no significant difference was observed between the control and stem sterilized groups (p=0.29).

The steam sterilized group demonstrated the highest fracture resistance that was followed by the chemically sterilized group, and the least with the dry heat sterilized group.

This study aimed to investigate the effect of growth modification treatments on oral health-related quality of life in adolescents aged 11 to 14 years with Class II malocclusion.

Eighty people participated in this case-control study. The case group (n=43) included adolescents with a history of Class II malocclusion treated with growth modification. The control group consisted of 37 adolescents with Class II malocclusion who were not treated. Both groups were given a translation of the Child Perception Questionnaire (CPQ), measuring the quality of life in four domains: oral symptoms, functional limitations, psychological health, and social well-being. Data were statistically analyzed by SPSS software and a significance level of 0.05 was considered.

The oral health-related quality of life of the case group was better than the control group in all areas although this difference was not statistically significant (P=0.204).

The oral health-related quality of life between two groups was not different; however, the difference in mental health components between the two groups was clinically negligible.

To validate Pi angle with other sagittal discrepancy indicators like Beta angle, Yen angle and W angle in skeletal Class I, II and III patients, to correlate the Pi angle with the size and position of the mandible, and to evaluate the reliability of Dolphin imaging software.

One hundred fifty subjects were nominated based on the inclusion criteria and their lateral cephalograms were traced based on their ANB angle, they were placed into skeletal Class I, II and III groups. A-P discrepancy indicators and parameters of the size and position of the mandible were traced manually and digitally.

Pi angle had 85% and 100% accuracy in identifying skeletal Class II and III groups, respectively. Parameters of the morphology of the mandible were found to have statistically significant correlation with Pi angle e.g., mandibular base length (-0.265), SNB (-0.408), articular angle (0.277), facial angle (-0.800), and Y axis (0.728), etc.  When data was compared between manual and digital tracing, there was no difference in the mean values of Pi angle (P=0.87), Beta angle (P=0.73), and Yen angle (P=0.64) between the two techniques, suggesting good accuracy of Dolphin imaging software.

The Pi angle could accurately differentiate the sample into skeletal Class I, II and III groups. A statistically significant correlation was determined between Pi angle and most of the parameters of the size and position of the mandible. It was found that the imaging software Dolphin 3D is dependable to the analysis of cephalometric variables, which are not available in the software.

Metallic corrosion of orthodontic appliances occurs due to potentially damaging physical and chemical agents. The major corrosion products of stainless steel are iron, chromium, and nickel. When tissues are exposed to certain concentrations of a primary irritant for certain periods, cytotoxic effects may be observed. Hence, this study aimed to assess the cytotoxicity of nickel, iron, and chromium ions during fixed orthodontic treatment onto human keratinocytes (HaCaT).

The metal ions nickel, chromium, and iron in concentrations of 75, 150, 300, 600, 1200, and 2400 μg/ml were prepared to assess the cytotoxicity on HaCaT cells. The control group included these metal ions at 0 μg/ml. Cytotoxicity was assessed by microculture tetrazolium (MTA) assay. The half maximal inhibitory concentration (IC50) was measured and a scanning electron microscope (SEM) was used to assess the morphological changes of the HaCaT cells. The Kruskal-Wallis test followed by the Bonferroni’s post hoc test was carried out to determine the difference in percentage inhibition within and between the groups at various concentrations.

Nickel showed the highest cytotoxic effects in comparison with other metal ions.  Iron hexahydrate, nickel hexahydrate, and chromium hexahydrate have shown an IC50 value of 552.4 μg/ml, 364.1 μg/ml, and 641.1 μg/ml inhibition in HaCaT cells respectively. Cytotoxic effects were dose dependent on the tested materials. Comparison of percentage inhibition between groups showed a p-value of 0.372.

The present study showed that the nickel, chromium, and iron ions induced a wide range of toxicity to human keratinocytes. The IC50 values ranged between 364.1 and 641.1. Nickel was the most toxic metal tested between the concentrations of 75 to 2400 μg/ml for HaCaT cells compared to other metal ions used in the study.

This study aimed to assess the relationship of upper pharyngeal airway volume with tongue position in different sagittal and vertical skeletal patterns using cone-beam computed tomography (CBCT).

CBCT images of 225 participants (149 females, 76 males) over 18 years of age were evaluated in three groups with sagittal Class I, II, and III skeletal patterns. Class I and II individuals were subdivided into three vertical subgroups high angle, normal, and low angle. The CBCT scans were evaluated three-dimensionally, and the volume of the lower nasopharynx (LNP), oropharynx (ORP), and velopharynx (VLP) was calculated in addition to the total upper pharyngeal airway volume (TV). The tongue position (according to Graber’s analysis and D1-D5 and D1’-D5’ lines) was determined, and the tongue height (TGH) was measured. Data were analyzed by one-way and two-way ANOVA, Tukey’s test, and Pearson’s and Spearman’s correlation tests (a=0.05).

The volume of the LNP was significantly larger in Class II than in Class III patients (P<0.05). VLP volume (r>0.5, P<0.05) and TV (r>0.5, P<0.05) in Class I high angle participants had a significant correlation with D1.

The present results showed greater LNP volume in Class II than in Class III individuals. In some variables (VLP, ORP, TV, intraoral airway volume) no significant difference was observed between different sagittal and vertical groups. Most of the airway variables (TV, VLP, ORP) had no correlations with some tongue variables (TGH, D1, D3, D4, D4’, D5, intraoral airway volume) in different skeletal patterns.

This study aimed to compare the incidence of mucosal lesions and pain during orthodontic treatment with fixed versus removable orthodontic appliances.

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.

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).

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.

Maxillary transverse deficiencies pose significant challenges in orthodontics, necessitating effective treatment methods. Traditional approaches like rapid maxillary expansion (RME) have demonstrated limitations, especially in skeletally mature patients. Skeletal anchorage-based expansion methods, such as miniscrew-assisted rapid maxillary expansion (MARME), have emerged as viable alternatives, offering advantages in terms of reduced dental side effects and improved stability.

Report of a Case: 

A 14-year-old female presented with a severely constricted maxillary arch and intricate occlusal issues. This case report details the utilization of MARME as a treatment modality. Miniscrews were strategically placed by an orthodontist specialist, and the expansion process was carefully monitored. Post-treatment outcomes revealed a significant increase in midpalatal suture opening width, showcasing the effectiveness of MARME. Cone beam computed tomography images demonstrated a notable expansion of the transverse dimension, leading to improved occlusal relationships.

Skeletal anchorage-based expansion, particularly MARME, stands out as a preferred method for addressing maxillary constriction in adolescents. This case serves as an illustration of the feasibility and distinctive advantages of Temporary Anchorage Devices (TADs) in the context of maxillary expansion for skeletally mature patients.

The COVID-19 pandemic has presented significant challenges for healthcare professionals, particularly in the field of dentistry. This study aimed to evaluate the changes in infection control measures in dentistry before and during the pandemic among Iranian dentists.

An analytical cross-sectional study was conducted from June to December 2020, and included dental healthcare professionals (DHCPs) practicing dentistry in Iran. Participants completed a web-based survey that included demographic profiles, practice-related details, and information on implemented infection control measures. Data were subjected to statistical analysis using the software SPSS v. 26, and a P-value<0.05 was considered statistically significant. 

A total of 303 dentists, 200 (66%) of whom practiced specialized dentistry and 103 (34%) were general dentists, responded to the questionnaire. The majority of participating dentists (85.5%) were aware of the importance of patient screening for COVID-19 symptoms. There was a statistically significant rise in adherence to hand hygiene practices. The utilization of personal protective equipment (PPE), such as gloves, masks, and face shields also exhibited significant increases amid the pandemic. Dentists shifted from using surgical masks to N95 respirators (p=0.05) and white coats to disposable gowns (p<0.001). We noted a significantly greater tendency towards adopting air ventilation systems, surface disinfection and prescribing preprocedural mouth rinses among DHCPs.

The study findings indicate increased compliance with infection control protocols during the COVID-19 pandemic among Iranian DHCPs and highlight the modifications made to infection control measures in dentistry.

The aim of this retrospective study was to evaluate the maxillary transverse dimensions in individuals with palatal impacted maxillary canines relative to the control group without dental impactions using cone-beam computed tomography(CBCT). 

Sixty CBCT images of the individuals were classified into two groups: 29 in the palatal impacted canine group and 31 in the control group. To determine the maxillary width at four levels, CBCT DICOM files were processed using the software OnDemand 3D to analyze maxillary transverse parameters. Basal width at molar (BWM), alveolar width at first molar (AWM), basal width at premolar (BWPM), and alveolar width at premolar (AWPM) were the four levels at which the maxillary transverse dimensions were measured. The independent T- test was utilized when comparing the impacted canine group and the control group. The level of statistical significance was set at a P-value less than 0.05 for all tests.

Regarding the transverse maxillary measurement, there was no significant difference between the impacted canine group and the control group for the BWM, BWPM, and AWPM (P≥0.05). For the AWM, statistically significant differences were not found between the maxillary palatal impacted canine group and the control group (P=0.05).

No significant differences were observed between the impacted canine group and the control group in terms of maxillary transverse dimensions. Further research is needed to explore the relationship between maxillary canine impaction and maxillary transverse dimensions.