Iranian Journal of Orthodontics
Year:2024 | Volume:19 | Issue:1|Papers Count:12

Aim: Assessing the midpalatal suture (MPS) maturation is crucial to successfully predicting rapid maxillary expansion. Therefore, radiographic measurement of the suture width is vital for treatment planning. This study compared MPS ossification using cross-sectional maxillary occlusal radiographs and cone-beam computed tomography (CBCT) scans to aid clinicians in making better treatment decisions.Methods: In this study, 33 patients were selected as the cohort and categorized into two groups according to their chronological age. Group I included individuals in the growth phase, aged 8‒16 years, while group II encompassed post-adolescent and young adult participants aged 16‒25 years. The percentage of MPS ossification was calculated using the suture obliteration index calculated on axial cross-sectional images. Statistical analysis was performed using the Student’s t-test at a significance level of P<0.05.Results:  No significant difference was found between occlusal radiographs and CBCT scans in assessing MPS ossification in the anterior part (P>0.05). However, significant differences were noted in the suture obliteration index in the anterior (P=0.031) and posterior (P=0.035) parts, with higher mean values obtained by occlusal radiographs. In contrast, significant differences favoring CBCT were found in the anterior part (P<0.001) with higher mean values; no significant difference was found in the posterior part. Lastly, no significant difference was noted in the posterior part between the two imaging modalities (P>0.05).Conclusion: For MPS assessment, both CBCT and occlusal radiography can provide predictable results. However, it is notable that CBCT still has the upper hand in providing better and more accurate results.

Aim: Sleep bruxism is a parafunctional oral habit frequently related to sleep arousal. The masseter inhibitory reflex (MIR) causes reflex inhibition of voluntary contractions of the elevator muscles induced by intense peri- or intraoral mechanical or electrical stimulations. This study aimed to investigate the changes in the MIR of patients with SB, and the effect of different treatment modalities on MIR.Methods: In this case‒control study, 100 individuals were randomly assigned to four equal groups : conservative treatment (G1), occlusal splint treatment (G2), low-level laser therapy (LLLT) treatment (G3), and control (G4). The MIR was tested in all the participants before and one month after treatment.  Student’s t-test , ANOVA  followed by the post hoc for pairwise comparisons as well as Pearson’s correlation test were used for statistical analysis.Results: All MIR components of the patients had longer right and left SP1 and right and left SP2 latencies (P=0.017, P=0.043, P<0.001, and P=0.04, respectively) and shorter right and left SP1 and right and left SP2 durations (P=0.021, P=0.021, P<0.001, and P<0.001, respectively) compared to the control group. The right SP1 and SP2 latencies were prolonged in G3 versus G1 and G2 (P=0.026 and P<0.001, respectively). In contrast, the left SP2 latency was prolonged in G2 compared with G1. The right and left SP2 duration was not significantly different between the three treated groups. The left SP1 duration was not significantly different between the three treated groups. Gender did not affect MIR parameters.Conclusion: Patients with sleep bruxism had an abnormal MIR response. LLLT was the most effective compared to other treatment modalities.

Aim: This study aimed to determine the changes in mandibular incisor proclination and mandibular arch widths after leveling the curve of Spee (COS).Methods: Patients included in this quasi-experimental study were scheduled for fixed orthodontic treatment with a non-extraction therapy in the mandibular arch, no posterior crowding, eruption of all mandibular teeth except third molars, no spacing, and Little’s irregularity index greater than 2. The COS depth and mandibular arch widths (inter-canine and inter-molar widths) were measured on plaster casts and recorded in millimeters. Mandibular incisor inclinations were measured on a cephalogram according to the incisor mandibular plane angle (IMPA) and lower incisor to NB (L1) angle. The pre- and post-treatment values were compared using paired-samples t-test. Pearson’s correlation was used to analyze the association between COS changes and other variables. P-value<0.05 was considered statistically significant.Results: Fifty-eight subjects with an average age of 25.10±6.81 years participated in this study. COS depth values significantly reduced after treatment (2.34±0.78 mm vs. 1.75±0.56 mm) (P<0.001). Average IMPA and L1-NB values significantly increased following COS flattening (P<0.001). Mandibular inter-canine and inter-molar widths also significantly increased after treatment (P<0.001). Pearson’s correlation revealed a significant inverse correlation between COS changes and mandibular arch width and mandibular incisor proclination values (P<0.001 for both). The patients’ age and gender did not significantly affect the COS depth.Conclusion: Flattening of COS leads to an increase in lower incisor proclination and mandibular arch width.

Aim: The present study tried to find the proper bonding and debonding technique to preserve the natural enamel surface and avoid discoloration.Methods: Sixty newly extracted human premolars were randomly divided into three groups, and three orthodontic adhesives were applied to bond the brackets: chemically cured System 1 Plus adhesive (Ormco, USA) (CC), light-cured resin (Transbond XT, 3Munitek, USA) (LC), and resin-modified glass ionomer cement (Fuji Japan) (GI). The specimens were immersed in black tea for one week and debonded. Four prophylactic methods were applied to remove residual resin: 1) tungsten carbide bur (TC), 2) tungsten carbide bur + Sof-Lex polisher (TC + SL), 3) tungsten carbide bur + One Gloss Polisher (TC + OG), and 4) tungsten carbide bur + PoGo polisher (TC + PG). The enamel color was measured according to the CIE standard system (Commission International de l’Eclairage) by Konica Minolta CS Spectroradiometer equipment twice: 1) natural enamel color before bonding and 2) after bonding, staining, debonding, and polishing. The ΔE value is the tooth discoloration, which is measured from the mean Δa*, Δb*, and ΔL* values using the following formula ΔE = [(ΔL*)2 + (Δa*)2 + (Δb*)2]1/2 for each group. Then, it was statistically analyzed using a t-test.Results: Regarding adhesive materials, CC adhesive showed higher discoloration than LC in all the polishing methods. The lowest discoloration was observed in GI. The highest ΔE* values were obtained using TC only, which was deemed insufficient to remove the residual adhesives.Conclusion: Applying TC + Sof-Lex and TC + PoGo equally enhanced the results; therefore, they were the best polishing methods.

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.

Aim: Functional appliances such as twin blocks are widely used to treat skeletal Cl II malocclusions. Myofunctional effects are one of the critical features of these appliances. The present study aimed to investigate the muscular effects of clear and traditional twin blocks.Methods: In this randomized clinical trial, 60 skeletal Class II div 1 patients were randomly divided into two groups: clear twin block (CTB) and traditional twin block (TTB). Electromyographic (EMG) evaluation of masseter, anterior temporalis, orbicularis oris, and mentalis muscles was carried out during deglutition, rest, whistling, and forced occlusion before insertion (T1) and six months (T2) after insertion of the appliance. Data were analyzed using independent t-test, paired t-test, and Wilcoxon’s signed-rank test at the 0.05 significance level.Results: There were no significant differences in T2 values between the groups (P>0.05). The intragroup comparisons showed a significant change from T1 to T2 in the CTB group for the clenching of the masseter muscle and in the TTB group for swallowing and rest position of the anterior temporalis muscle and swallowing of the masseter muscle (P<0.05).Conclusion: Both CTB and TTB changed the muscular activity of circumoral muscles. No significant difference was found when the post-treatment muscular activity of the two groups was compared.

Aim: This study aimed to measure bone-specific alkaline phosphatase (B-ALP) levels in saliva and determine how they relate to different stages of skeletal development, as assessed by hand-wrist X-rays using the Hagg and Taranger method. Since orthodontic treatment is closely linked to an individual’s growth, the development of the jaws, face, and overall body, and how they affect the alignment of teeth, the suggestion to use biomarkers to evaluate an individual’s skeletal maturity has emerged as a promising approach. Unlike traditional radiographic methods, which are subjective and based on morphology, biomarkers provide objective indicators related to the patient’s physiology, and they do not involve radiation exposure or magnification errors. The main goal of this study was to measure B-ALP levels in saliva and examine their correlation with varying degrees of skeletal maturity. In a positive correlation, the total ALP present in saliva could be a valuable biological indicator in growing patients.Methods: Thirty patients were randomly selected for the study based on the inclusion criteria: Age of the individual: 9‒19 years, with good general health and no nutritional issues. A sample of unstimulated whole saliva was collected using a passive drooling method to estimate levels of the bone alkaline phosphatase using an enzyme-linked immunosorbent assay (ELISA) kit. After saliva collection, hand-wrist radiographs were immediately obtained and manually traced onto 50-micron-thick lead acetate tracing sheets using an 0.5-mm lead pencil. The hand-wrist radiographs were then categorized into five groups, which involved analyzing the morphology of the hand-wrist radiographs: group SO (prepubertal), group S (pubertal onset), group MP3 (peak pubertal), group DP3 (pubertal deceleration), and group RJ (growth completion).Results: There were significant differences between the B-ALP levels between different skeletal ages. The salivary B-ALP values of the group MP3 were significantly higher than those of groups SO and RJ. The mean salivary B-ALP levels consistently increased from the group SO to the group MP3, followed by a gradual decrease.Conclusion: Salivary alkaline phosphatase activity was significantly higher during the peak pubertal period (group MP3) compared to both the pre-peak (group SO) and post-peak (group RJ) values. This finding suggests that salivary bone alkaline phosphatase can be used as an additional indicator alongside conventional skeletal maturation indicators to assess pubertal development.

Aim: Proper education in oral and dental health behaviors and preventive orthodontics is vital for preventing dental diseases and orthodontic abnormalities. Since children spend much time in schools and in contact with their teachers, the current study aimed to assess the level of awareness about preventive orthodontics among school hygiene instructors in Sari, Iran.Methods: Seventy-one hygiene instructors were included in this semi-experimental study with a pre-test and post-test design. The participants completed a questionnaire before any intervention. A one-day workshop about preventive orthodontics was held for the instructors, and an educational CD and pamphlet were provided for them. The participants were asked to answer the same questions after a month. Data were compared and analyzed with SPSS 22, using paired t-test and chi-squared test.Results: The findings revealed that the training could significantly increase the level of orthodontic awareness among hygiene instructors (P<0.001). However, the participant’s level of education and years of experience was not significantly associated with their level of awareness (P>0.05).Conclusion: Considering the importance of health education, efficient training should be provided for school hygiene instructors to increase their awareness in the field of preventive orthodontics.

Aim: The aim was to determine the effect of first premolars’ extraction with maximum incisor retraction on airway magnitude and hyoid bone position in cases with bimaxillary dentoalveolar protrusion.Methods: Lateral cephalograms of patients with Class I skeletal and dental relationships were retrospectively recruited. Inclusion criteria were 15‒30-year-old patients with bimaxillary proclination, who had undergone all first premolar extraction with maximum incisor retraction. Patients with dentofacial anomalies, chronic mouth breathing, and those who had undergone tonsillectomy or adenoidectomy were excluded. Pre- and post-treatment lateral cephalograms were digitally analyzed for airway measurements and hyoid bone position. Paired-samples t-test was used for statistical analysis. P<0.05 was considered statistically significant.Results: Thirty-three patients, comprising 22 females and 11 males, with a mean age of 24.39±6.92 years, were included. Statistically significant differences were found in airway dimensions from pre-treatment to post-treatment; upper airway size between soft palate and posterior pharyngeal wall (SPP-SPPW) decreased by 1.91 mm (12.78%), at uvula and middle posterior wall (U-MPW) by 2.51 mm (20.60%), at tongue base to posterior-inferior point on middle pharyngeal wall (TB-TPPW) by 3.39 mm (24.26%), and vallecular to lower pharyngeal wall by 1.51 mm (9.94%). The vertical position of the hyoid bone also decreased significantly, as indicated by the inferior movement of hyoidale (H) by 4 mm (3.8%). There were no significant changes in the horizontal position of the hyoid bone.Conclusion: Premolar extraction with maximum retraction in bimaxillary protrusion cases can decrease the airway dimension and increase the vertical position of the hyoid bone.

Aim: Orthodontic treatment often leads to gingival hyperplasia, which may complicate oral hygiene and necessitate surgical interventions such as gingivectomy. This study compared the efficacy of ceramic burs versus scalpels in gingivectomy procedures for orthodontic patients, focusing on periodontal outcomes and pain.Methods: This case series describes six orthodontic patients with gingival hyperplasia. The patients were between 15-25 years and were non-smokers. They underwent gingivectomy using two methods: ceramic burs (NTI® Soft Tissue Trimmers) and traditional scalpels. Preoperative oral hygiene instructions were given, and intraoral photographs were obtained. Clinical measurements included the plaque index (PI), gingival index (GI), and bleeding index (BI). Bleeding, pain (using a visual analog scale), and periodontal indices were assessed at several time points postoperatively.Results: Both groups showed significant improvements in gingival hyperplasia, PI, and mean GI. However, the ceramic bur group experienced lower postoperative pain compared to the scalpel group. One patient in the scalpel group required analgesics for pain management. The results highlighted the effective management of gingival hyperplasia with both methods but with a potential advantage in pain management for the ceramic bur group.Conclusion: This study indicated that both ceramic burs and scalpels are effective for gingivectomy in orthodontic patients. Ceramic burs might offer a less painful alternative, although both methods effectively manage gingival hyperplasia. Further studies with a larger sample size and longer follow-ups are required to confirm the present findings and potentially recommend ceramic burs as a preferred method for gingivectomy.

Aim: Canine teeth have a significant impact on the order and proper function of other teeth. Canine impaction can have negative esthetic and functional effects. This study investigated the success rate of orthodontically-assisted eruption of maxillary canine teeth according to age, sex, and type of impaction in Shahrekord city, Iran.Methods: In this retrospective study, panoramic radiographs of 112 patients who had initiated their orthodontic treatment at least 2 years earlier and had completed it by 2023 were evaluated. Cone-beam computed tomography scans were also used when necessary to assess the details. The type, depth, and angle of erupted and impacted canine teeth were determined. The data were analyzed by the Fisher's exact test and t-test.Results: Impacted canines successfully erupted in 72 patients (64.3%). Palatal impaction was more common (71.4%) than buccal impaction (28.6%). Regarding the impaction depth, type C had the highest frequency (63.4%), followed by type B (30.4%), and type A (6.3%). There was no significant correlation between the gender of patients and success rate of assisted eruption (P>0.05), but age and type of impaction were correlated with the success rate (P<0.05). The erupted canine teeth had a significantly higher mean angle relative to the occlusal plane compared with non-erupted teeth (P<0.05).Conclusion: The success rate of orthodontically-assisted eruption of impacted maxillary canine teeth was high, and patients in the age range of 15 to 18 years with grade II impaction showed the highest success rate of orthodontically-assisted eruption of impacted canine teeth.

Aim: The Bolton analysis is commonly used by orthodontists. The Bolton ratios of different populations are significantly different from the standard values of Bolton. This study aimed to examine Bolton's anterior and overall ratios in various malocclusion types in Mashhad, Iran, in comparison to the Bolton’s standards.Methods: This descriptive-analytical study included 240 study models of patients (121 males and 119 females) in four groups (n= 60 cases) of normal occlusion, Class I, Class II, and Class III. The mesiodistal dimensions of the teeth were measured twice using a digital caliper. The anterior and overall ratios of Bolton were calculated. Kruskal Wallis, Chi-square, one-way ANOVA, Tukey’s post hoc test and one-sample t-test were used for statistical analysis. P-value<0.05 was considered as significant.Results: The mesiodistal width of the maxillary lateral incisors in normal occlusion cases was greater than in Class I, Class II, and Class III malocclusions (P<0.05). Conversely, the mesiodistal width of the maxillary first and second premolars was the greatest in Class II and the smallest in Class III malocclusion (P<0.05). There was no correlation between Bolton ratios (anterior and overall) and gender or malocclusion groups (P>0.05). Additionally, the anterior ratio was significantly higher than Bolton's standard in Class I and III malocclusion groups (P<0.05). The overall ratio of the normal occlusion group was significantly lower than Bolton's original ratio (P<0.05).Conclusion: The size of premolars in Class III patients is smaller than in Class II which is consistent with the type of malocclusions. In Iranian individuals with normal occlusion, the overall Bolton’s ratio is higher than the standard.