Malocclusion Groups Research Articles

Airway Analysis in Different Malocclusions - A Cephalometric Study

Background: It was essential to evaluate respiratory function when diagnosing and planning orthodontic treatment. Based on the correlation between pharyngeal airway space and craniofacial structure, airway width was hypothesized to be an indicator of airway patency in different groups of skeletal malocclusion. Aim: The purpose of this study was to investigate age and gender related changes in pharyngeal airway dimensions in different sagittal skeletal relationships Materials and Method: Sixty lateral cephalograms of patients aged 10-30 years with no pharyngeal pathology or nasal obstruction were retrospectively selected and categorized into skeletal Class I (n = 20), Class II (n = 20), and Class III (n = 20) malocclusion based on ANB angle. McNamara's airway analysis was used to quantify upper- and lower-airway dimensions. The analyses of intergroup differences were performed using a one-way ANOVA, an independent t-test, and Tukey's test as a post-hoc test. Results: Participants in the study ranged in age from 20.57 ± 5.41 years (males) and 20.03 ± 4.58 years (females) were included in the study. The upper pharyngeal airway (UPA) dimensions demonstrated a positive correlation with age. In both genders, the mean upper pharyngeal airway (UPA) size exceeded the lower pharyngeal airway (LPA) size, but neither age nor gender was associated with statistically significant differences in skeletal malocclusion. Conclusion: It was shown that skeletal malocclusions of different types have no effect on the upper and lower pharyngeal airways and that the upper and lower pharyngeal airways are not influenced by age or gender.

Enhancing Orthodontic Renewal and Retention Techniques: A Systematic Review.

Orthodontists have a variety of options available for retainers. Research in Orthodontics focuses on assessing outcomes important to clinicians; however, there is inconsistency in how these outcomes are selected and evaluated. This review sought to assess the effects of different orthodontic retainers on patients' quality of life (QoL). Various approaches were employed in this systematic review, and a thorough search was conducted across six databases. The review involved a comprehensive evaluation of six included studies, highlighting changes in dental structure post-treatment, emphasizing the role of extraction procedures and the quality of debonding in improving retention. The study identified key outcomes for orthodontic clinical trials, highlighting orthodontists' preferences for specific retainer types. Moreover, it discussed the impact of sociocultural influences on retention care. Involving patients actively in discussions about whether to end or extend the retention phase was deemed essential. Noteworthy improvements in occlusal outcomes were linked to extraction treatments. Gender and malocclusion severity influenced QoL before and after orthodontic treatment. The degree of improvement observed in the Class III malocclusion group was comparatively lower than that in the Class I and Class II groups. Orthodontic treatment was found to yield favorable psychological outcomes, as evidenced by notable enhancements in self-esteem and social engagement among individuals. Fixed appliances were shown to negatively affect oral health-related quality of life (OHRQoL), particularly for those with aesthetic and functional concerns. A consensus has been reached on the essential themes and outcomes that should be incorporated in clinical trials related to orthodontic retention for non-cleft and non-surgical cases.

Comparison between basal arch width in normal occlusions and class Ⅱ malocclusions by using cone-beam computed tomography

ObjectiveThe purpose of this research was to investigate the measurements of maxillary and mandibular basal arch width in male and female with normal occlusion, and to compare dental arch width difference between normal occlusion and ClassⅡ malocclusion groups could be helpful in orthodontic diagnosis and treatment planning. MethodsCone-beam computed tomography (CBCT) images from 133 individuals (76 males and 57 females) with normal occlusion and 64 (25 males and 39 females) with skeletal Class II malocclusions were evaluated. The distances between canines, first molars (basal arch widths: BAW) and second molars were measured from CRs (center of resistance) of the teeth and the projection of first molars on buccal bones (WALA distance) were measured. ResultsThere were significant differences in male and female maxillary and mandibular dental transverse widths. The normal range of the maxilla and mandible basal bone widths differences were −2 mm–2 mm (−0.05 ± 2.17 mm). The normal occlusion and Class Ⅱ groups exhibited significant differences in the width of the intercanine and first molars. Sella-nasion-A point angle (SNA) and Sella-nasion-B point angle (SNB) in the Class Ⅱ male group were positively correlated with the width between the maxillary canines. For individuals with normal occlusions, the width of the mandible at the second molar was greater than that of the maxilla, so more attention should be paid to the width of the second molar when considering clinical treatment. ConclusionMeasuring the width of the maxilla and mandible basal bones from the resistance center of the first molar was a feasible and repeatable method can be used in clinical practice. The data could serve as a reference for orthodontic treatment planning. More consideration should be paid to the horizontal dental problems of the treatment plan for Class Ⅱ patients. And the width of the mandible at the second molar was greater than that of the maxilla, so more attention should be paid during treatment.

Evaluation of Glenoid Fossa Position in Class II Malocclusion Associated with Mandibular Retrusion and Class III Malocclusion Associated with Mandibular Protrusion

ABSTRACT Objective: This study examined the glenoid fossa in Class II and Class III malocclusions with mandibular retrusion and protrusion. Materials and Methods: A retrospective investigation examined 60 Class II and 60 Class III cephalometric radiographs. Cephalometric landmarks and glenoid fossa measurements were taken. Statistical analysis contrasted the two malocclusion groups’ glenoid fossas. Results: Class II malocclusion had a much lower mean Sella–Nasion–Condylion (SNCd) angle (glenoid fossa sagittal position) than Class III (14.6° ± 1.9). Class II malocclusion had a lower mean Sella–Nasion–Gonion (SNGo) angle (32.5° ± 4.3) than Class III (36.2° ± 3.9). The SNCd angle and SNGo angle in both groups demonstrated a negative correlation, demonstrating a relationship between the glenoid fossa and the mandibular sagittal axis. Conclusion: The glenoid fossa location differs significantly between Class II malocclusion with mandibular retrusion and Class III with protrusion. Class II malocclusion has a posterior glenoid fossa, while Class III has a less posterior one. Understanding these links may help patients receive more personalized treatment.

Masseter Muscle Thickness in Relation to Facial Form in Angle’s Normal Occlusion and Malocclusions: An Observational Study

ABSTRACT Background: Various clinical studies performed in adults have shown the relationship between craniofacial morphology and masticatory muscle function. However, the growth of the masticatory muscle has not received such attention, when compared with the volume of studies on the skeletal growth of face. With this background and considering the widespread use of ultrasonography (USG), the following study was undertaken to provide some insights into the relationship between muscle and bone and facial morphology. Methods: This was a prospective, observational study conducted over a period of three years from 2012 to 2015 to assess the correlation between the thickness of the masseter muscle in Angle’s normal occlusion and the various malocclusions of the dental arch as well as the facial form. Patients with a full complement set of teeth, normal tooth morphology, Angle’s normal occlusion, Angle’s class I-III malocclusion, those with a history of third molar extraction, and impaction were included in the study. Those with a history of any prior orthodontic treatment, restorations, or any missing teeth (except the third molar) were exempted from the study. The greater thickness of masseter muscle in relaxed and clenched state was recorded on USG. Facial morphology was determined with the aid of facial photographs. Results: The study was conducted on 140 patients. The class I normal occlusion group had the thickest masseter muscle, while the class III malocclusion group had the thinnest masseter muscle. Facial parameters showed highly significant gender-wise differences in class I normal occlusion, class I malocclusion, and class II division II malocclusion. There was a significant negative co-relation between the thickness of masseter muscle and facial forms in all the categories of Angle’s classification as indicated by a negative regression coefficient B (P < 0.05) Conclusion: The masseter muscle thickness correlated directly with male gender and normal occlusion, and inversely with the degree of malocclusion and facial form.

DIGITAL ANALYSIS OF TOOTH SIZES AMONG INDIVIDUALS WITH DIFFERENT MALOCCLUSIONS: A STUDY USING THREE-DIMENSIONAL DIGITAL DENTAL MODELS

The objective of the study was to examine the sizes of teeth, in digital models of patients with different malocclusions, with the help of three-dimensional measurement software. 68 digital models of 34 patients aged between 21 and 29 years were analyzed. A review was carried out to determine the participants according to Angle's classification, leaving 24 patients in the class I group and 10 patients in the class II group. Then, the patients' plaster models were scanned, using the Dentsply Sirona Cerec Omnicam Software 5.2 digital scanner, thus obtaining their digital format. NemoStudio-2022 software was then used to perform tooth size measurements. After analysis of the measurements, it was observed that the anterior and general mesiodistal sizes were not statistically related to the different malocclusions. There was also no difference between the groups in terms of values of the previous proportion, nor when evaluating the values of the general proportion between the groups. Finally, no malocclusion group had a significant relationship with the alteration of anterior or general mesiodistal size. The difference in mesiodistal tooth size of the antero-upper and antero-inferior teeth does not contribute to the appearance of Angle Class I, Class II and Class III malocclusions since there were no statistically significant relationships in this regard.

Association between skeletal malocclusion, masseter muscle volume, and bite force: CBCT study

Background/Aim: This study aimed to evaluate the masseter muscle volume and maximum bite force in individuals with different types skeletal malocclusion. The researchers conducted a comparative analysis to assess the relationship between skeletal malocclusion groups and masseter muscle volume, as well as maximum bite force. By examining these variables, the study aimed to provide insights into the underlying mechanisms of craniofacial deformities. Materials and Methods: The study was conducted on a sample of 60 young adult patients (18-30) years. These patients were referred to the clinic for Cone Beam Computed Tomography (CBCT) imaging. Radiological measurements were taken using CBCT images, and bite force was measured using a force measurement sensor. Results: The results of the study indicated a statistically significant relationship in both muscle volume and bite force among the different skeletal malocclusion groups. However, no correlation was observed between muscle volume and other variables. The statistically significant relationship between vertical groups and muscle volume/bite force suggests that these measures could potentially serve as supplementary diagnostic tools. However, the uneven distribution of vertical directional groups indicates that they may not be entirely reliable as diagnostic tools. Therefore, further investigation using larger sample sizes is necessary to better understand the relationship between skeletal malocclusion, bite force, muscle volume. Conclusions: The absence of correlation between muscle volume and bite force suggests that CBCT may not be reliable method for soft tissue imaging. This implies inadequacy of CBCT in capturing soft tissue details.

Mental Foramen Position, Shape, Continuity, and Symmetry Among Malocclusion Patients: A Radiographic Study.

Many dental treatments need exact knowledge of the anatomical location of the mental foramen (MF). This retrospective research uses orthopantomograph (OPG) to assess the MF of orthodontic patients in Saudi Arabia and their position, symmetry, shape, and connectivity. One hundred and eighty panoramic radiographs of patients having orthodontic treatment were analyzed for the location, form, symmetry, as well as bilateral preservation of the MF. The patients were of varied ages, genders, and degrees of malocclusion and were divided into three classes: Class I (60), Class II (60), and Class III (60). Chi-squared tests and other descriptive statistics were employed to examine the data for statistical significance. When looking at the right side of the mouth, the most frequent location for MF was position 3 (between the apexes of the first and second premolars; 50.6%), whereas on the left side, it was location 4 (near the apical of the second premolar; 47.2%). The most typical form of MF has an irregular shape. MF location on the left side and continuity types differed significantly across malocclusion groups (p<0.05). OPGs of Saudi orthodontic patients demonstrated a significant variability of position and continuity of the MF across different classes of malocclusion. The third most frequent position was between the first and second premolars, while the shape of MF showed variation across the age of the patients. Hence, this precise comprehension of the anatomical and morphological diversity of the MF is of utmost significance for dental professionals.

Comparison of upper and lower lip position, length and thickness in sagittal and vertical malocclusion

This study aimed to compare the upper and lower lips position, length, and thickness in different malocclusions, in randomly selected 180 patients’ pre-treatment lateral cephalograms. The subjects were grouped sagittally by using Steiner’s analysis and Wits appraisal and vertically based on Frankfort horizontal and mandibular plane (FHMP) angle and lower facial height. One-way ANOVA was applied to compare the upper and lower lip positions, thickness, and length in sagittal and vertical malocclusion and independent sample T test was applied for comparison between genders among soft tissue variables. Post-hoc Dunnett T3 was performed for comparison of lip variables in adjacent malocclusion groups. The level of significance was not less than or equal to 0.05 The anteroposterior position of the upper and lower lips with respect to E and S planes and upper and lower lip thicknessaried significantly (p &lt; 0.05) in all classes of sagittal malocclusion, ---Continue

Bolton Ratio in Different Groups of Malocclusions in Iraqi Population

It is important clinically to evaluate Bolton ratio and it influences the organizing of orthodontic management. The objective of the present study was to relate anterior and overall Bolton ratios in dissimilar Angle's malocclusion classes of Iraqi sample with Bolton’s standards, and also to find if there is any gender difference. This study involved dental casts from one hundred twenty subjects 14-25 years old divided into three main malocclusion groups Class I, Class II and Class III from Saladin city. Statistically no significant differences in anterior and overall Bolton’s ratios were recorded in malocclusion classes and no significant gender difference in any malocclusion group.

A Correlative Study to Assess the Relationship among Ameloglyphics, Cheiloscopy, Rugoscopy in Skeletal and Dental Malocclusions

Introduction: Benefits of preventive and interceptive orthodontic procedures can be availed by early prediction of malocclusion. Early diagnosis is achievable when parameters having similar embryological origin and development period, similar to that of the craniofacial structures are identified and studied. Few such parameters are the enamel rod end patterns, lip prints, and palatal rugae patterns. The intent of this study was to assess the correlation between ameloglyphics, cheiloscopy, rugoscopy and skeletal and dental malocclusions. Materials and Method: A cross-sectional study with one hundred subjects were classified into 3 groups based on cephalometric analysis into skeletal class I, class II and class III malocclusion and were further divided into 4 dental malocclusion groups namely class I, class II division 1, class II division 2 and class III based on the Angle's classification of malocclusion. Ameloglyphics patterns, lip prints and palatal rugae patterns were recorded for each subject and statistically analyzed with chi-square test and Spearman correlation test. Result: Class I malocclusion subjects revealed a predominant curve palatal rugae pattern, type II lip print pattern and wavybranched ameloglyphics patterns were observed with statistically significant association. In class II malocclusion, the predominant palatal rugae pattern observed was straight pattern, type I lip print pattern and linear branched ameloglyphics patterns were statistically significant. Subjects in class III malocclusion group were associated significantly with the annular pattern of palatal rugae, type I lip print pattern, and stem pattern of ameloglyphics. Conclusion: A curve rugae pattern in class I malocclusion, a straight pattern in class II malocclusion, and an annular pattern in class III malocclusion were observed. For the Lip Prints, a highly statistically significant association was observed between class I malocclusion and type II lip print pattern. Ameloglyphics, revealed a statistically significant association between wavy branched pattern and class I malocclusion, linear branched pattern and class II malocclusion and stem pattern with class III malocclusion.

Mandibular Asymmetry in Orthodontic Patients with Different Malocclusion Patterns an Orthopantomographic Evaluation

Objectives: To investigate the variation in mandibular asymmetry on right and left sides for different malocclusions. Study design and setting: It was a cross sectional study carried out in Orthodontic Department at Bahria University Dental College. OPG’s of 171 orthodontic patients were collected. The sample was divided into class I, II and III malocclusions. Methodology: The OPG was traced for condylar and ramal heights for both right and left sides. From these readings, the asymmetry index (AI) was calculated for each side. The significance of height variations between the right and left sides, for each malocclusion was calculated using independent sample t-test. Pearson correlation was used to find the association of asymmetry between the two sides when comparing each malocclusion with the other. One-way ANOVA was used to find the significance of differences in asymmetry index of both sides between different malocclusions. Results: The ramal heights were significantly different for each malocclusion with p values of 0.00 and 0.02 for right and left side, the p value of the variations in condylar heights was however 0.66 and 0.12 for the two sides. There was a strong positive correlation of the condylar and ramal height on both sides between all three malocclusions. The p value for condylar AI was 0.97 and 0.15 for ramal AI. Conclusion: The ramus height showed a significant variation in asymmetry while the asymmetry index variations were insignificant between different malocclusion groups.

Impact of occlusal proprioception on static postural balance

Conflicting results on the effects of occlusal proprioceptive information on standing sway have been reported in the literature, partly due to the heterogeneity of the occlusal criterion studied and the experimental protocol used. In this study, occlusal functions, different mandibular positions and visual conditions were used to investigate the involvement of occlusal proprioception information in static postural balance. Postural adjustments of 26 healthy young adults, divided into Class I malocclusion and Class I normocclusion groups, were studied in upright position, in five mandibular positions (1 free, 2 centric and 2 eccentric), with and without vision. Due to different reported test durations, postural parameters were examined for the first and last halves of the 51.2 s acquisition time. A permutation ANOVA with 4 factors was used: group, mandibular position, vision, time window.Mean length of CoP displacement was shorter with vision (ES = 0.30) and more affected by vision loss in the free than in the intercuspal mandibular position (ES = 0.76 vs. 0.39), which has more tooth contacts. The malocclusion group was more affected by vision loss (ES = 0.64). Unexpectedly, with vision, the mean length was smaller in one eccentric occlusion side compared to the other (ES = 0.51), but independent of the left or right side, and more affected by vision loss (ES = 1.04 vs. ES = 0.71). The first-time window of the acquisition time, i.e. 25.6 s, was sufficient to demonstrate the impact of dental occlusion, except for the sway area.Comparison of the two visual conditions was informative. With vision, the weight of occlusal proprioception was not strictly related to occlusal characteristics (number of teeth in contact; centered or eccentric mandibular position), and it was asymmetrical. Without vision, the lack of difference between groups and mandibular positions suggested a sensory reweighting, probably to limit postural disturbance.

Association among Orthodontic Malocclusions, Paranasal Sinuses Anatomic Variations and Adenoid Vegetation in Children Using CBCT.

The aim of this study is to evaluate the relationship between orthodontic malocclusion, paranasal sinus (PS) variations, and adenoid vegetation in a group of pediatric patients with chronic rhinosinusitis. Clinical and radiographical data were retrospectively evaluated and 58 patients were diagnosed as having chronic sinus disease. Cone-beam computed tomography (CBCT) images were acquired with Newtom-3G. Anatomical variations of the PS were assessed on every section. Additionally, for cephalometric analysis, the images were imported into the InVivoDental software program. A total of 252 anatomical variations, which encompassed 19 different types, were detected in the current study. Concha bullosa was the most common anatomical variation, at 72.4%. Septum deviation was the second most common one, at 67.2%. The Class III group exhibited a significantly higher prevalence of concha bullosa and secondary middle turbinate than the other groups. While adenoid vegetation was most common in the Class III group, sinusitis and antral disease were most common in the Class II group. Overall, Class III subjects exhibited fewer PS variations. In conclusion, concha bullosa emerged as the most prevalent anatomical variation, with distinctive patterns observed across different malocclusion groups. Therefore, CBCT is useful, especially in pediatric patients, due to its low dose advantage.

Determination of Bolton’s Ratio in Different Malocclusions of the Western Region of Saudi Arabian Population: A Retrospective Cross-Sectional Study

Background: Bolton’s ratio is a useful tool in orthodontic studies which helps determine the ratio of dental proportions. It is considered the 7th key to normal occlusion. Variations in different malocclusions can aid in diagnosis and planning the treatment. This study determines Bolton’s overall and anterior ratios for male individuals with different classes of malocclusion in the western region of Saudi Arabia. Methods: Ninety-six study model records were obtained from male patients attending the Orthodontic division of Preventive Dentistry, Faculty of Dentistry at Taif University, Saudi Arabia. The participants’ average age was 19.6 years. The study models were divided into three categories: Angle’s Class 1 (n=40), Angle’s Class 2 (n=36), and Angle’s Class 3 (n=20). To prevent bias, one of the authors measured the study casts using the ORTHOASSISTANT software program at two different time intervals. Intergroup differences were analyzed using one-way ANOVA. Results were considered statistically significant if the p-value of ≤ 0.05. Results: No statistically significant difference was observed in the overall ratio between the three types of malocclusions. However, class 2 and 3 malocclusions demonstrated significant differences in the anterior ratio. Both overall and anterior ratios in this population were higher than normal Bolton’s ratios. Conclusions: Bolton’s overall ratio did not differ significantly between various malocclusions, but Bolton’s anterior ratio did show significant differences between Class 2 and Class 3 malocclusion groups. This highlights the importance of orthodontists’ appropriate diagnosis and treatment planning in such cases.

Reflection on patients’ experience with orthodontic appliances wear and its impact on oral health related quality of life: observational comparative study

BackgroundThe objective of this study was to explore and compare patient’s experience with the use of a removable functional appliance or fixed orthodontic appliance and its influence on oral health-related quality of life.Material and methodsThis clinical trial included 81 participants having Class II Division 1 and age ranging between 10 and 16 years. The participants were included in any of a three equal groups according to the set inclusion and exclusion criteria; Group 1: patients treated with a Twin-Block functional appliance; Group 2: patients treated with a fixed orthodontic appliance only; and Group 3 (control group): patients not in orthodontic treatment yet. The COHIP SF-19 was used. Patients were given the questionnaire as follows: Group 1: (1) after at least 8 months from starting treatment; (2) after completing phase 1 by 2–3 months without wearing the appliance; Group 2: (1) just before debonding; (2) after finishing the treatment by 2–3 months without any appliances; and Group 3: (1) at the patient’s first visit to the orthodontic clinic; (2) after 2–3 months from the first visit to the orthodontic clinic and before starting any treatment.ResultsThe 81 participants were 31 males and 50 females with median age of 13 years. The total COHIP SF-19 scores at baseline were 57 (49–64), 67 (63–72), and 47 (42–53) for the Twin-Block, the fixed appliance, and the malocclusion groups, respectively. Two-month mean scores adjusted to the baseline scores were 64.82 ± 1.15, 65.65 ± 1.47, and 54.45 ± 1.44 for the Twin-Block, the fixed appliance, and the malocclusion groups, respectively.ConclusionsBoth at baseline and two-months (adjusted to the baseline scores), participants in the malocclusion group showed compromised socio-emotional quality of life and reported the poorest total OHRQoL. At the baseline, better socio-emotional and total OHRQoL was reported by the fixed appliance group compared to the Twin-Block group but, after two months both groups gave similar sores. Therefore; patients’ perceptions about their experience with the orthodontic appliance might change.

Tooth size discrepancies in Kosovar adolescents with different malocclusion classes

The goal of this study was to evaluate tooth size discrepancies in Kosovar adolescents according to the Bolton’s analysis, and to determine the differences between gender and malocclusion classes. A sample of 400 Kosovar adolescents, aged 13–19 years with various malocclusion categories (class I, II, III) according to the Angle’s classification, was randomly selected. The anterior tooth size ratio, overall tooth size ratio, posterior tooth size ratio, as well as distribution of tooth size discrepancies were assessed. The normality of distribution was assessed by the Kolmogorov-Smirnov test, the differences between genders by the Independent Sample T-test, the Mann-Whitney U-test, and differences among malocclusion groups by ANOVA, the Kruskal-Wallis, and the Dunn’s post-hoc tests. The tooth size ratios of men and women did not differ significantly. The results also demonstrated significant differences among the malocclusion classes only for the anterior tooth size ratio (p&lt;0.05). The overall and posterior ratios did not differ significantly within malocclusion classes. The percentages of Kosovar subjects with a deviation of more than 2SD from the Bolton average for the anterior and overall ratios were 41.37 and 23.79, respectively. The genders did not differ significantly regarding tooth size ratios. Among the malocclusion classes, the anterior ratio differed significantly. In Kosovar subjects, tooth size discrepancies tend to be higher compared to Bolton’s averages.

An Association of Morphological Characteristics of Palatal Rugae and Dental Malocclusion in an Adult Indian Population: A Cross-Sectional Study.

Introduction The formation of palatal rugae is completed in the early intrauterine stage, and because of their unique and permanent pattern in each individual, they can be utilized in forensics to identify a person. Objective The primary objective of this study was to determine an association between the rugae pattern and the dental malocclusion system described by Angle. Materials and methods A prospective cross-sectional, observational study was conducted on pretreatment dental casts of 400 subjects in an age range of 18-40 years. The samples were divided according to Angle's system of classification of malocclusion into Class I, Class II, and Class III. The number, length, pattern, and orientation of the three anterior-most primary rugae on both sides of the palatal region were studied. Results Significant differences were noted in the mean number of palatal rugae and mean lengths of rugae 1 and 2 on the right side (p < 0.001) and rugae 3 on the left (p < 0.001) side among the different malocclusion groups. Curved and wavy patterns were predominant, and significant differences were found among the groups (p < 0.05), whereas non-significant differences were observed in the rugae orientation between the groups on the right and left sides. Conclusions The current study showed significant differences in the length, number, and pattern of the palatal rugae among Angle's classes of malocclusion. Clinical implications Palatal rugae can be effectively used to identify dental malocclusion at an early stage and can, therefore, help intercept the developing malocclusion.

A study of transverse maxillomandibular discrepancy and dental compensation in early mixed dentition with skeletal Class III malocclusion without posterior crossbite.

To evaluate transverse maxillomandibular discrepancy and dental compensation in first molar areas in 7- to 9-year-old children with skeletal Class III malocclusion without posterior crossbite using cone-beam computed tomography (CBCT). The sample of this retrospective study consisted of 60 children (7 to 9 years old), who were divided into the skeletal Class III malocclusion group (study group, skeletal Class III malocclusion without posterior crossbite, N = 31) and the Class I occlusion group (control group, Class I occlusion with one or two impacted teeth, N = 30). CBCT data were obtained from the database of the Department of Radiology of Hospital of Stomatology, Shandong University. For three-dimensional reconstruction of the head, the dental arch width, basal bone width, and buccolingual inclination angle were measured using MIMICS 21.0 software. Independent-sample t tests were used to compare the two groups. The mean age of the children was 8.18±0.83years. The width of the maxillary basal bone was significantly smaller in the skeletal Class III malocclusion group (59.75 ± 3.14 mm) than in the Class I occlusion group (62.39 ± 3.01 mm) (P < 0.01). The mandibular basal bone width was significantly larger in the skeletal Class III malocclusion group (60.00 ± 2.56 mm) than in the Class I occlusion group (58.19 ± 2.42 mm) (P < 0.01). The difference in the width of the maxillary and mandibular bases in the skeletal Class III malocclusion group (-0.25 ± 1.73 mm) was significantly different from that in the Class I occlusion group (4.20 ± 1.25 mm) (P < 0.01). However, there was no significant difference in the upper or lower dental arch width between the two groups (P > 0.05). The buccal inclination of the maxillary molars in the skeletal Class III malocclusion group (31.4° ± 8.9°) was significantly higher than that in the Class I occlusion group (17.64° ± 7.3°) (P < 0.01), as was the lingual inclination angle of mandibular molars (45.24° ± 8.3° vs. 37.96° ± 10.18°; P < 0.01). Transverse maxillary and mandibular discrepancies in the posterior area and transverse dental compensation were found in the early mixed dentition of patients with skeletal Class III malocclusion without posterior crossbite. This suggests that even in the absence of posterior crossbite, maxillary expansion can be attempted to correct the maxillomandibular transverse discrepancy.

Geometric analysis of tooth size among different malocclusion groups in a Hispanic population

Tooth size ratio is important for optimal dentofacial esthetics, occlusal interdigitation, and postorthodontic treatment stability. Tooth geometry influences tooth size ratio; therefore, tooth size normative data may not be practical across diverse ethnic groups. This study aimed to determine whether there are significant differences in 3-dimensional tooth size among patients in the Hispanic population with Angle Class I, II, and III malocclusions. The data were collected using intraoral scanned orthodontic study models representing Hispanic orthodontic patients with Angle Class I, II, and III malocclusions. The scanned models were digitized and transferred to a geometric morphometric system. Tooth sizes were determined, quantified, and visualized using contemporary geometric morphometric computational tools. Tooth size was determined for all teeth and showed a significant difference in 4 out of 28 teeth: Maxillary right first molar, mandibular left second molar, mandibular right first molar and mandibular right second molar. This significant difference was noted among females and affected different malocclusion groups. Tooth size discrepancy in the Hispanic population varies among malocclusion groups, and the variation is determined by the participant's gender.