Angle Class Research Articles

Anterior Open Bite Treatment in the Mixed Dentition: a Brief Review and Case Report

Anterior open bite (AOB) is a vertical plane malocclusion characterized by a negative vertical overbite and can be classified according to its nature: dentoalveolar or skeletal. The dentoalveolar anterior open bite (DAOB) occurs in individuals who have a good relationship between the bone bases and its etiology is associated with environmental factors. DAOBS´s treatment tends to have a favorable prognosis and it's up to the dentist to choose the most adequate method in each case. Thus, the objective of this study is to present a case report of DAOB. Female patient of 6 years old attended the Preventive Orthodontics Clinic of the Faculty of Dentistry of Araçatuba - UNESP, having as main complaint “open bite”. In the anamnesis the patient revealed that used a pacifier and presented a digital sucking habit. The patient was in the first transitional period of mixed dentition with permanent incisors and first molars partially erupted. The diagnosis was of Angle Class I malocclusion with dentoalveolar anterior open bite and dentoalveolar anterior crossbite of the deciduous right maxillary canine. The bi-helix with crib appliance was installed and the patient was oriented to perform myofunctional exercises daily. This therapeutic protocol represents an efficient and effective approach for the correction of DAOBs providing improved aesthetics, social well-being and a more appropriate and correct occlusion that allows oral functions (deglutition, speech and chewing) to work properly. The results acquired through this treatment are essentially of dentoalveolar nature.

Advansync2 Current Trend for Correction of Skeletal Class II Malocclusion: A Case Study

The most frequent skeletal discrepancy seen across all age groups is class II malocclusions, which account for roughly 15-20% of orthodontic procedures. The most frequent type of malocclusion, Angle's class II division 1 malocclusion, is challenging to treat, especially when an underlying skeletal misalignment is present. For the treatment of skeletal class II malocclusion brought on by retrognathic mandible, different fixed functional appliances have been developed over the years by various authors. The molar-to-molar appliance, also known as Advansync2 (Ormco Co, Glendora, Calif.), has lately been employed successfully among the fixed functional appliances available for class II correction. This fixed tooth-born functional appliance has the benefit of enabling the use of fixed orthodontic therapy simultaneously. As a result, the length of the entire treatment can be shortened. We provide two case reports of patients who used the Advansync2 class II corrector and describe the skeletal and dentoalveolar abnormalities that were noticed as a result of the treatment. The observed outcomes were equivalent to those of the majority of fixed functional equipment, although in every instance, the treatment time was greatly shortened.

The Impact of Orthodontic Treatment on Facial Appearance in Angle Class III Patients: A Mini Review

Angle Class III malocclusion has a strong genetic influence that can occur in several generations of the same family group. This dentofacial deformity can be identified from an early age, even in childhood. The perception of beauty in the transition phase to adolescence has a greater weight, because in this phase there are immense physiological changes. The need for attention through aesthetic enhancement generates vanity, which can have both beneficial and harmful influences. Nowadays, the young generation craves prominence and subsequently values the exaggerated importance of beauty and the quest for aesthetic perfection. A young patient with a dentofacial deformity caused by Angle Class III malocclusion has a major facial impact. They are usually the victims of teasing, nicknames and psychological pressure and bullying. They become embarrassed, irritable and their self-esteem and social integration suffer. From this perspective, early treatment in children can be beneficial, reducing the psychological burden of facial and dental alterations in the future. The purpose of this article is to review the literature on the facial aspects resulting from orthodontic treatment in Angle Class III patients.

Two-dimensional facial measurements for anterior tooth selection in complete denture treatment

PurposeAnterior tooth selection is one of the most challenging parts in determining tooth dimensions and critical to the aesthetic aspect of the complete denture treatment. However, the methods for anterior tooth size selection using facial measurements are still controversial. This study aimed to investigate the relationship between dental measurements and facial measurements, and to establish the anterior tooth size prediction equation using facial dimensions in the Thai population for the complete denture treatment. Materials & methodsOne hundred and twenty-five Thai participants (53 men and 72 women) aged 18–35 years old with Angle class I occlusion, did not currently undergo orthodontic treatment, had normal alignment on the maxillary anterior teeth, no attrition, abrasion, proximal restoration or prosthesis were investigated. One frontal facial photograph and one dental photograph of each participant were made using an image analyzing program (ImageJ version 1.53b) to measure the six horizontal facial distances, five vertical facial distances and three dental distances as 2D facial and dental measurements. Pearson correlation and multiple linear regression analysis were performed. ResultsThe difference of facial and dental measurements between men and women were statistically significant (P < .001). Interpupillary width, interlateral canthal width, intercommissural width and bizygomatic width were correlated to dental measurements in both sexes. Intermedial canthal width and lip thickness were correlated to dental measurements in women. Face length and lateral canthus to lower border of face were correlated to dental measurements in men. Prediction equations of each dental measurement were established using only horizontal facial dimension and using both horizontal and vertical facial dimensions. ConclusionsFacial and dental dimensions are sex-dependent. Facial measurements can be applied in a regression equation to predict dental measurements. Adding vertical dimensions of facial measurements to the prediction equations of anterior tooth size selection results in a higher R squared to 0.444. This finding can be used as a tool for anterior tooth size selection in the complete denture treatment.

Dentoalveolar and Soft Tissue Changes Following en-Masse Anterior Retraction With Different Force Vectors in Subjects With Bidental Protrusion: A Retrospective Evaluation.

Introduction The aim of the study is to determine the effects of different vertical force vectors acting on dentoalveolar and soft tissues while applying a retraction force using various anchorage sources and their effects on these tissues. Material andmethods Based on the selection criteria, a total of 35 patient case records with Angle's Class I bidental malocclusion and incompetent lips treated with four premolar extractions were included. Retraction was achieved using a NiTi coil spring with two different force vectors. The anchorage in group 1 was enhanced by a transpalatal arch (TPA)and Lower Stabilizing Arch(LSA) in the upper and lower arch, respectively, with a force vector parallel to the occlusal plane,whereas in group 2, the force vector using Temporary Anchorage Devices (TADs) was 15 - 20 degrees to the occlusal plane. The skeletal, dental, and soft tissue were obtained using 40 parameters. Intra-group comparisons between pre- and post-treatment records were conducted using a paired t-test, while inter-group comparisons were conducted using an independent t-test. Result Significant anchor loss was observed in group 1, indicated by mesial movement of molar crowns by (-2.10±0.50) in the maxillary arch and (-1.75±0.38) in the mandibular arch. Distal movement of incisors following premolar extractions with both studied force vectors resulted in an improvement in lip procumbency and incisor inclinations, without any significant skeletal changes.Molar mesial movement was observed in subjects treated with conventional anchorage. Conclusion En masse anterior retraction did lead to anchorage loss when carried out without TADs.Altering the force vector did not produce significant changes in tooth movement along the vertical plane.

A Novel 3D Evaluation of the Correlation Between the Condylar Position and Angle Classification in a Lebanese Population: A Pilot Study

Introduction: The temporomandibular joint (TMJ) is one of the most complex joints. Its morphology varies between individuals, and even between the left and right sides. Several studies have found a significant relation between certain occlusal features and joint morphology. Cone-beam computed tomography (CBCT) imaging is currently the most widely adopted modality for the examination of the TMJ. Objective: This study aimed to compare the joint space in a Lebanese cohort with different Angle classification using CBCT. Methodology: We retrospectively analyzed CBCT images performed at the Saint Joseph University of Beirut in Lebanon, over a period of 1 year, between 2021 and 2022. Four clearance values were selected, representing the minimum distance between the temporal bone and the mandibular condyle that defines the joint space: 0.5 mm, 1 mm, 1.5 mm, and 2 mm. For each value chosen, we looked for the presence or not of a visible surface. This surface corresponds to the area of the condyle with a distance from the condyle to the temporal bone less than or equal to the chosen value. Results: Twenty-nine patients aged between 12 and 60 years old were included; 12 (41%) were males and 17 (59%) females. We classified 48 CBCT images (23 on the right side and 25 on the left side) into three groups according to Angle’s classification: class I (n=14), class II (n=29), and class III (n=5). For a distance of [0-1.5 mm] corresponded a surface of 0 mm2. For the interval between [1.5-2 mm] corresponded a surface of 18,8 mm2 for class I subjects, 16,6 mm2 for class II, and 30,5 mm2 for class III. The results showed no statistically significant differences between the articular spaces and the different types of occlusion. Conclusion: The three-dimensional evaluation of the condylar position by CBCT showed that there are no significant differences between the joint spaces and the different types of occlusion according to Angle’s classification.

Skeletal and dento-alveolar changes obtained with customised and preformed eruption guidance appliances after 1-year treatment in early mixed dentition.

The aim of this study was to assess the skeletal and dento-alveolar changes produced by a customised eruption guidance appliance (EGA) and a preformed EGA in subjects presenting a skeletal class II pattern during early mixed dentition and to evaluate the differences between the two devices. All subjects included in the study were randomly selected from the record's archive according to the following inclusion criteria: (1) patients presenting upper central incisor and first permanent molars fully erupted; (2) early mixed dentition with age between 7 to 9 years old; (3) Angle class I or class II malocclusion; (4) increased overjet > 4 mm;(5) deep bite with at least 2/3 overlapping of the incisors; (6) no previous orthodontic treatment apart from maxillary expansion treatment. All children belonging to the case group received treatment with a 3D printed EGA whereas the other patients belonging to the control group were treated with preformed EGA. Records consisted in digital dental models and lateral cephalogram at the beginning (T0) and after 1 year of treatment (T1). Data collected on the digital models included the dentoalveolar changes in overbite, overjet, sagittal molar relationship, and dental crowding. Cephalometric tracings were computed by a single blinded observer using Dolphin Imaging software. Statistical analysis was performed with SPSS (version 25.00; IBM Corp, Armonk, NY). Comparison regarding the cephalometric changes between T1-T2 was carried out with paired t-test. Difference in distribution regarding sagittal molar and canine relationship and anterior crowding between groups at T1 and T2 has been computed with chi-square test. The independent sample t-test was used to perform the between group comparison. In the short time, both the appliances showed to be effective in correcting class II malocclusion, anterior crowding, overjet and overbite. Custom-made appliance demonstrated to be significantly more effective in correcting anterior crowding, the dento-skeletal vertical relation and position of permanent incisor compared to the preformed appliance. Adopting a customised device, effects due to an average prescription appliance used to a specific patient can be reduced, resulting in more predictable results.

Full single arch distalization in Class II malocclusion using subzygomatic temporary anchorage devices: A case report

Abstract Distalization of the maxillary molars is among the most commonly employed nonextraction treatment strategies for angle Class II malocclusion. This approach is primarily recommended for subjects with dentoalveolar maxillary protrusion or minor skeletal abnormalities. A case of a 17-year-old Hispanic male patient with Class II skeletal base with Class II end on canines and molars, upper anterior crowding, severe overjet, and moderate overbite is hereby reported. He refused extraction; therefore, he was offered full single upper arch distalization using subzygomatic temporary anchorage devices (TADs). After 11 months of retraction, the TADs were removed and it was observed that the overjet and overbite were now within normal values and midline shift was also corrected. Satisfactory leveling and alignment, alleviation of crowding, and Class I molar and canine relationship were achieved. The aim of this case report was to describe full single arch distalization using subzygomatic TADs in a patient with Class II skeletal, molar, and canine relationships.

Developing a new tool for scoliosis screening in a tertiary specialistic setting using artificial intelligence: a retrospective study on 10,813 patients: 2023 SOSORT award winner.

The study aims to assess if the angle of trunk rotation (ATR) in combination with other readily measurable clinical parameters allows for effective non-invasive scoliosis screening. We analysed 10,813 patients (4-18years old) who underwent clinical and radiological evaluation for scoliosis in a tertiary clinic specialised in spinal deformities. We considered as predictors ATR, Prominence (mm), visible asymmetry of the waist, scapulae and shoulders, familiarity, sex, BMI, age, menarche, and localisation of the curve. We implemented a Logistic Regression model to classify the Cobb angle of the major curve according to thresholds of 15, 20, 25, 30, and 40 degrees, by randomly splitting the dataset into 80-20% for training and testing, respectively. The model showed accuracies of 74, 81, 79, 79, and 84% for 15-, 20-, 25-, 30- and 40-degrees thresholds, respectively. For all the thresholds ATR, Prominence, and visible asymmetry of the waist were the top five most important variables for the prediction. Samples that were wrongly classified as negatives had always statistically significant (p ≪ 0.01) lower values of ATR and Prominence. This confirmed that these two parameters were very important for the correct classification of the Cobb angle. The model showed better performances than using the 5 and 7 degrees ATR thresholds to prescribe a radiological examination. Machine-learning-based classification models have the potential to effectively improve the non-invasive screening for AIS. The results of the study constitute the basis for the development of easy-to-use tools enabling physicians to decide whether to prescribe radiographic imaging.

Short- and Long-Term Prediction of the Post-Pubertal Mandibular Length and Y-Axis in Females Utilizing Machine Learning.

The aim of this study was to create a novel machine learning (ML) algorithm for predicting the post-pubertal mandibular length and Y-axis in females. Cephalometric data from 176 females with Angle Class I occlusion were used to train and test seven ML algorithms. For all ML methods tested, the mean absolute errors (MAEs) for the 2-year prediction ranged from 2.78 to 5.40 mm and 0.88 to 1.48 degrees, respectively. For the 4-year prediction, MAEs of mandibular length and Y-axis ranged from 3.21 to 4.00 mm and 1.19 to 5.12 degrees, respectively. The most predictive factors for post-pubertal mandibular length were mandibular length at previous timepoints, age, sagittal positions of the maxillary and mandibular skeletal bases, mandibular plane angle, and anterior and posterior face heights. The most predictive factors for post-pubertal Y-axis were Y-axis at previous timepoints, mandibular plane angle, and sagittal positions of the maxillary and mandibular skeletal bases. ML methods were identified as capable of predicting mandibular length within 3 mm and Y-axis within 1 degree. Compared to each other, all of the ML algorithms were similarly accurate, with the exception of multilayer perceptron regressor.

Effects of headgear timing on dental arch changes from 7 to 18 years of age: a follow-up study.

Dental arch effects after cervical headgear (CHG) treatment have been researched from several different perspectives. However, the long-term effects of CHG timing are still unknown. To analyse the long-term effects of CHG timing on dental arches. A total of 67 children with Angle Class II malocclusion comprised the study group in this trial. The participants were randomized into two equal-sized groups. In the early group (EG, n = 33), treatment was started after the eruption of the first upper molars. In the later-timed group (LG, n = 34), treatment was started 18 months later compared with the early group. Long-term effects were measured from dental casts taken at five time points between 7 and 18 years of age. The total maxillary dental arch length was achieved earlier, the gained length persisted better in the long term, and significantly more space was achieved in EG compared with LG (P = .048). The intermolar width in the maxillary dental arch was more stable and was reached earlier in EG compared with LG (P = .002). The results showed that in terms of total mandibular arch length increases, EG males benefited the most and LG females the least from CHG treatment (P = .031). Both genders benefited from earlier CHG treatment. The maxillary dental arches remained longer, and the final width was gained earlier in EG compared with LG.

Influence of miniscrew-assisted rapid palatal expansion (MARPE) on the interdental papilla height of maxillary central incisors

ObjectivesTo evaluate the influence of miniscrew-assisted rapid palatal expansion (MARPE) on the interdental papilla height of maxillary central incisors.Materials and methodsPatients who completed MARPE treatment at the Radboud University Medical Center between 2018 and 2021 were included in this retrospective study. The papilla height between the maxillary central incisors was evaluated on frontal intraoral photographs taken before expansion (T0) and 1.5 years after MARPE treatment (T1) using the Jemt classification. The difference in Jemt score at T0 and T1 was the primary outcome variable. In addition, gender, age, Angle classification, MARPE duration, midpalatal suture maturation stage, maximal central diastema (MCD) immediately after expansion, crown width to length ratio (W/L), pretreatment overlap of maxillary central incisors, and the distance between the approximal contact point of the central incisors and the bone crest (CP-B) were also record.ResultsTwenty-two patients were included (2 men, 20 women, mean age 27.3 ± 8.8 years) and 4 patients (18%) showed a significant reduction in the Jemt score following MARPE (p = 0.04), indicating papilla recession. Interdental papilla recession was significantly associated with the increase of CP-B (p = 0.02), smaller W/L (p < 0.01), overlapping of maxillary central incisors (p < 0.01), and smaller MCD immediately after expansion (p = 0.02).ConclusionsOne and a half years after MARPE, 18% of patients exhibited mild recession of papilla height of the maxillary central incisors. Overlapping and smaller W/L of maxillary central incisors were prognostic factors for interdental papilla recession.Clinical relevanceClinicians have to be aware of and inform the patients about the occurrence of papilla recession following MARPE.

The validity of I-Scan in diagnosis of gastroesophageal reflux disease

Background: The evaluation of patients with suspected gastroesophageal reflux disease (GERD) frequently represents a diagnostic dilemma. Confirmation of the presence of the esophogeal mucosal injury is one of the roles of endoscopy in GERD diagnosis. In this context, there are limitations of white light endoscopy (WLE) because of the inadequate visualization of the minute mucosal changes and the uncertainty in describing the severity of mucosal injury. I-SCAN technology helps in revealing fine details of the GI mucosa. Aim: to evaluate the diagnostic efficacy of I-SCAN technology as compared to white light endoscopy (WLE) in Egyptian patients suffering from GERD symptoms. Patients and methods: This study included adult patients with GERD questionnaire (Q) score ≥ 8 points. The distal esophagus was examined by WLE followed by I-SCAN 2 to evaluate the presence of mucosal injuries and to classify GERD severity according to the Los Angles (LA) classification &amp; its Japanese modification, respectively. Biopsies were taken from the lower esophageal mucosa as well as from the visible mucosal breaks and subjected to histopathologic examination. Results: Sixty patients were enrolled; 32 (53.3%) were females &amp; 28 (46.7%) were males. WLE showed erosive reflux disease (ERD) in 41 patients (68.3%); while 19 patients (31.7%) showed no mucosal breaks. As regard LA classification; 18 of the cases were classified as grade A (30%); 15 as grade B (25%); 7 as grade C (11.7%) and 1 as grade D (1.7%). Reexamination of distal esophagus by I-SCAN 2 showed minimal change esophagitis (MCE) (grade M) &amp; ERD in 57 patients (95%); while only 3 patients (5%) showed no mucosal changes (grade N). As regard the modified LA classification; 16 cases were classified as grade M (26.6%); 12 as grade A (20%); 21 as grade B (35%); 7 as grade C (11.7%) and 1 as grade D (1.7%). There was perfect agreement of WLE with I-SCAN 2 in LA grades B, C &amp; D. There was poor agreement of WLE with I-SCAN 2 in cases who had no mucosal breaks &amp; LA grade A cases on WLE (weighted Kappa was 0.11); as 16 cases were reclassified as grade M on I-SCAN 2 (had no mucosal breaks on WLE) and 6 cases were reclassified as class B on I-SCAN 2(were classified as grade A on WLE). As regard the histological proven reflux esophagitis (HPRE), it was present in 41 (68.3%) of the studied cases with statistically significant higher proportion of male gender. It was present in 28 (68.3%) of the patients who had ERD on WLE; 13(68.4%) of the patients who had no mucosal breaks on WLE; 38 (66.6%) of the cases who had grade M or ERD on I-SCAN 2 &amp; the three patients who had grade N on I-SCAN 2.GERD Q score ranged from 10 to 12 points with median of 11 points. It was significantly higher in patients with HPRE (11.4 ± 1.8 points) than those without (10.3 ± 1.3 points) (p= 0.026). GERD Q score strongly correlated with both the modified LA grade by I-SCAN 2 (p=0.03) and the histological severity score (p=0,016). On univariate &amp; multivariate analysis, male gender and GERD Q score &gt; 11points were significant predictors of HPRE (p &lt; .001). ROC analysis curve showed that GERD Q score at a cut-off &gt; 11points was a significant predictor of HPRE with a sensitivity of 47%, specificity of 85%, AUC of 66.7% and p = 0.015. Conclusion: I-SCAN technology may improve the diagnosis of the esophogeal mucosal injury in GERD patients. There was poor agreement of WLE with I-SCAN 2 in patients who had no mucosal breaks &amp; those with LA grade A on WLE. However, there was perfect agreement of WLE with I-SCAN 2 in patients with LA grades B, C&amp; D. GERD Q score had positive correlation with both the modified LA grade on I-SCAN 2 and the histological severity score. Male gender and GERD Q score &gt; 11points were significant predictors of histological proven reflux esophagitis.

Retrospective Analysis of the Airway Space Changes in Dentofacial Deformity after Two-Jaw Orthognathic Surgery Using Cone Beam Computed Tomography.

Orthognathic surgery is used to modify anomalies in maxillomandibular position; this process can significantly affect the anatomy of the airway and cause functional changes. This study aims to define the impact of mandibular maxillary movement on the airway of subjects with dentofacial deformity. A retrospective study was conducted on subjects with Angle class II (CII group) and Angle class III (CIII group) dentofacial deformities. The subjects were treated via bimaxillary surgery; for all of them, planning was performed with software and 3D printing. Cone beam computed tomography (CBCT) was obtained 21 days before surgery and 6 months after surgery and was used for planning and follow-up with the same conditions and equipment. Was used the superimposition technique to obtain the maximum and minimum airway areas and total airway volume. The data were analyzed with the Shapiro-Wilk test and Student's t-test, while Spearman's test was used to correlate the variables, considering a value of p < 0.05. Thus, 76 subjects aged 18 to 55 years (32.38 ± 10.91) were included: 46 subjects were in CII group, treated with a maxillo-mandibular advancement, and 30 subjects were in the CIII group, treated with a maxillary advancement and a mandibular setback. In the CII group, a maxillary advancement of +2.45 mm (±0.88) and a mandibular advancement of +4.25 mm (±1.25) were observed, with a significant increase in all the airway records. In the CIII group, a maxillary advancement of +3.42 mm (±1.25) and a mandibular setback of -3.62 mm (±1.18) were noted, with no significant changes in the variables measured for the airway (p > 0.05). It may be concluded that maxillo-mandibular advancement is an effective procedure to augment the airway area and volume in the CII group. On the other hand, in subjects with mandibular prognathism and Angle class III operated with the maxillary advancement and mandibular setback lower than 4 mm, it is possible to not reduce the areas and volume in the airway.

Behaviour and sun exposure in holidaymakers alters skin microbiota composition and diversity.

Introduction: The skin microbiota plays a crucial role in maintaining epidermal homeostasis. Ultraviolet radiation (UVR) and other environmental challenges can impact the skin microbiota through direct and indirect mechanisms. This study aimed to investigate the effects of sun exposure on the skin microbiota and its relationship with individual skin phototypes. Methods: Healthy volunteers (n = 21 [4M, 17F], mean age 33.2years) holidayed in a sunny destination for a minimum of 7days with swabs taken pre-holiday and up to 84days post-holiday. Participant group was categorised by individual typology angle (ITA) classification and the composition of the skin microbiota was examined using 16S rRNA gene sequencing. Results: In the entire cohort and at all time points, the major bacterial phyla were Actinobacteria, Proteobacteria and Firmicutes. There was a significant change in microbial beta diversity at day 28 post-holiday, compared to baseline, for all participants. However, when participants were segregated into three cohorts dependent on the degree of skin tanning response between baseline (pre-holiday) and immediately one-day post-holiday, there was a reduction in Proteobacteria in the sun-seeking participants 1day after the holiday, which recovered over time. Discussion: These findings suggest that sun exposure can affect the diversity and composition of the skin microbiota, which may have downstream effects on skin health.

Prevalence and Distribution of Malocclusion Using Dewey's Modification in Coastal Andhra Pradesh, India: A Cross-Sectional Study.

The aim of this study is to evaluate the prevalence and distribution of malocclusion among the coastal Andhra Pradesh population in south India. The present study has a retrospective cross-sectional study design done on orthodontic records of patients who attended the Department of Orthodontics and Dentofacial Orthopedics at Lenora Institute of Dental Sciences and Hospital,Rajamahendravaram, India. Angle's classification and Dewey's modification were used to assess the distribution and pattern of malocclusion in patients. Statistical analysis was done using Chi-square test. The distribution of Angle's Class I malocclusion (67%) was more common than Angle's Class II malocclusion (30.1%) and Angle's Class III malocclusion (2.1%). The distribution of Class II division 1 was 23.2%, whereas Class II division 2 was 2.1% and Class II subdivision was 5.6%. Gender distribution according to Angle's classification exhibited a statistically significant difference (p-value < 0.001). Dewey's Class I type 2 was identified as maximum with 43.6% but no statistically significant gender distribution was reported. Conclusion: Angle's class I malocclusion was more prevalent with a distribution of 67%, followed by Class II malocclusion (30.1%) and Class III malocclusion (2.1%). A significant number of female patients were reported with Class I and Class II malocclusion whereas Class III malocclusion was predominately seen in males. It was noticed that, among all the malocclusions, Dewey's Class I type 2 was observed to be maximum but no significant gender distribution was observed.

Impact of Low-Level Laser Therapy on Orthodontic Tooth Movement and Various Cytokines in Gingival Crevicular Fluid: A Split-Mouth Randomized Study.

A few investigations have detailed the influence of low-level laser therapy (LLLT) on orthodontic tooth movement (OTM), with varying results. The objectives of this study were twofold: to assess the impact of LLLT on OTM and various cytokine levels in gingival crevicular fluid and to contrast the pain levels experienced by patients receiving orthodontic treatment with and without LLLT. This split-mouth randomized controlled prospective study comprised 40 patients with an average age of 19.7±2.4 years with Angle Class I malocclusion combined with bimaxillary protrusion who were advised for extraction of the maxillary first premolar and bilateral canine distalization. The control-side canine was distalized solely by the coil spring. On the test arm, a low-level gallium-aluminum-arsenide semiconductor diode laser operating at 980 nm and 100 mW with a continuous-wave energy of 8 J/cm2 was used. The canine distalization on either side was measured with a digital caliper following the first premolar extraction (TO), one month after treatment (TOTM1), two months later (TOTM2), and three months later (TOTM3). The gingival index and the level of various cytokines were determined by an enzyme-linked immunosorbent assay at the beginning of the study, on the third and seventh days, and at four, eight, and 12 weeks following the canine distalization. The intra-group and inter-group comparisons were carried out using one-way analysis of variance (ANOVA) and t-tests, respectively, at a 5% significance level. The results show a highly statistically significant difference in the extent of canine distalization in the test group (TOTM1=2.92±0.44; TOTM2=1.04±0.1; TOTM3​=0.62±0.21 mm) in contrast to the control group (TOTM1=3.23±0.8; TOTM2=2.65±0.2; TOTM3​​​​=2.11±0.24 mm) (p<0.01). After three months of canine distalization, the laser and control group had 34 and 27 patients with mild gingivitis, respectively. Interleukin-1β and interleukin-6 concentrations surged with values of 0.74±0.13 and 0.049±0.001 pg/g at seven days following treatment in the laser group, respectively. The difference in tumor necrosis factor concentration between the groups was shown to be highly statistically significant in all treatment phases (p<0.001). The differences in the epidermal growth factor and microglobulin levels were found to be statistically significant within both groups from T0 to T5.The average visual analog scale (VAS) scores at several subsequent evaluations of the laser and control groups were found to be highly statistically significant. The findings imply that when the periodontal microenvironment is stimulated by orthodontic force, several paramount cytokines are released, triggering an ordered sequence of biological processes that appear to expedite OTM with reduced associated pain.

Effects of mouth opening breathing for different reasons on maxillofacial development in children

Objective:To explore the effects of mouth opening breathing for different reasons on children's maxillofacial development. Methods:One hundred and fifty-one children were selected as the research objects of this experiment. They were divided into 49 cases of adenoid hypertrophy group（group A）, 52 cases of tonsillar hypertrophy group（group B） and 50 cases of adenoid with tonsillar hypertrophy group（Group C）. Healthy children in the same period were selected as the control group, a total of 45 cases. The reflex nasopharyngeal measurement parameters, facial development indexes and cephalometric parameters of group A, group B, group C and control group were analyzed, and the incidence of Angle ClassⅡand Angle Class Ⅲ in group A, group B and group C were studied. Results:Compared with the control group, the reflex nasopharyngeal measurement parameters in group A, group B and group C was significantly different（P<0.05）, and the cephalometric parameters changed with variation in groups（P<0.05）. The incidence of Angle Class Ⅱ facial pattern in group A and group C was higher, but the incidence of Angle Class Ⅲ facial pattern in group B and group C was higher（P<0.05）. Conclusion:Adenoid hypertrophy leads to mandibular retraction; tonsil hypertrophy leads to anterior mandibular arch; adenoid hypertrophy and tonsil hypertrophy are easy to lead to clockwise rotation of the mandible. In clinical practice, to avoid children's uncoordinated maxillofacial development, we should correct the maxillofacial situation of children as soon as possible.

Management of Angle Class I malocclusion with crowding and anterior crossbite by unilateral premolars extraction

Crowdedteethhave a major negative influence on the dentomaxillary system. In addition toaesthetic concerns, which arethe main motivating factor for requesting dentaltreatment,there areother functionalconsequences that canbe factors favoringthe onset anddevelopment ofperiodontaldisease.This articlereportsthe treatmentofsevere crowding anddeepbite withpremolar extraction.A 20-year-old female presented withsevere crowding of the upper and lower anterior teeth. Thepatient complain- edabout facialaesthetics and convexprofile, andhadboth lower first molars extracted about 2 years ago. There was agenitionof the right upper first premolar,deep bite and anterior crossbite. Clinicalexamination showed a Class I relationship forthe teeth and cephalometric measurementsshowed a Class IIskeletal tendency.The left upper first premolar was extracted for anterior crowding correction andoverbitecorrection. Thespace ofthe missing lower first molar was used for correction oflower crowd- ing.A two-step extraction technique was used to correct the patient's verticalplaneandprofile. It is concludedthat upper first premolar extraction is one of the options in the treatment of crowding. Unilateral extraction treatment can be performed to achieve an aesthetically pleasing and functionally stable occlusion.

Study on the effect of chin morphology on orthodontic treatment.

To investigate the effect of different soft-tissue morphologies on the treatment of skeletal class Ⅰ malocclusion patients by analyzing measurement data before and after treatment. Pre- and post-treatment lateral cephalograms of 55 adult female Angle class Ⅰ patients were collected in the Department of Orthodontics, Hospital of Stomatology, Jilin University from January 2012 to December 2020. Chin soft-tissue morphologies in the lateral cranial radiographs were used to divide the patients into an abnormal chin morphology group (flat and retracted chins, n=27) and a normal chin morphology group (rounded and prominent chins, n=28). Relevant soft- and hard-tissue indexes were selected to study in-group varieties and intergroup differences in the varying chin morphologies before and after treatment. The chin-lip angle, mandibular chin angle, mandibular chin vertex angle, PP-MP, LL-E, UL-E, Po-Pos, and B-B' thickness in the abnormal chin morphology group were significantly higher than those in the normal chin morphology group (P<0.05). Furthermore, m∶BMe and n∶B'Mes in the abnormal chin morphology group were signi-ficantly lower than those in the normal chin morphology group (P<0.05). After treatment, the mandibular chin angle, mandibular chin vertex angle, U1-SN, L1-MP, LL-E, UL-E, SNA, SNB, and B-B' thickness of the abnormal chin morphology group significantly decreased (P<0.05), whereas the nasolabial angle, m∶BMe, n∶B' Mes, and Po-Pos significantly increased (P<0.05). In the normal chin morphology group, the U1-SN, L1-MP, LL-E, UL-E, and B-B' thicknesses decreased significantly (P<0.05), whereas the nasolabial angle significantly increased (P<0.05). Among them, m∶BMe and n∶B' Mes were positively correlated. Chin morphology affects the formulation of treatment plans. Compared with the normal chin morphology group, the abnormal chin morphology group required a larger retraction of incisors. Although the chin of soft-tissue morphology is related to the morphology of bones, the changes in soft tissue chin after treatment cannot be directly predicted according to the bone changes. Soft-tissue chin morphology affects the aesthetic assessment of the soft-tissue lateral profile and the change in soft tissue before and after treatment. The method of predicting the change in soft-tissue chin after treatment should consider the morphology of the soft-tissue chin.