Dental Arch Widths and Mandibular-Maxillary Base Width in Class III Malocclusions with Low, Average and High MP-SN Angles

Relationship of buccolingual inclination between the alveolar bone and first molar in different vertical facial types: A CBCT study

BACKGROUND

This study aimed to investigate the differences in the buccolingual inclination and transverse width of maxillary and mandibular first molars among different vertical facial types.

METHODS

In all, 78 samples were divided into three groups based on the GoGn-SN angle: the low-angle group (n = 26, mean age=24.21±5.11), average-angle group (n = 26, mean age=22.66±3.72), and high-angle group (n = 26, mean age=22.23±2.43). Cone beam computed tomography (CBCT) measurements were used to assess the buccolingual inclination of the axis of the maxillary and mandibular first molars, as well as the buccolingual inclination of the alveolar bone, the dental arch width, and the basal bone width. One-way ANOVA, the LSD test, and Pearson correlation analysis were performed.

RESULTS

The high-angle group showed significantly greater lingual inclination of the maxillary alveolar bone than the low-angle group and average-angle group (p < 0.001; p < 0.05). The difference in buccolingual inclination of the axis of the maxillary first molar and the alveolar bone was significantly greater in the high-angle group than in the low-angle group (p < 0.05). Both the maxillary and mandibular dental arch were significantly narrower in the high-angle group than in the other two groups. The mandibular basal bone was also significantly narrower in the high-angle group than in the low-angle group and average-angle group (p < 0.001; p < 0.01).

CONCLUSIONS

The alveolar bone of maxillary first molar in the high-angle group was more palatal inclined than that the low-angle group and the average-angle group, which suggests that orthodontists should pay more attention to the root-bone relationship in the high-angle group during expansion treatment to prevent bone fenestration and dehiscense.

Evaluation of three-dimensional reconstructed palatal morphology in skeletal class III subjects with different vertical patterns using cone beam computed tomography

BACKGROUND

This study aims to evaluate the difference of three-dimensional (3D) reconstructed palatal morphology between subjects with skeletal Class III and skeletal Class I in different vertical patterns using cone beam computed tomography (CBCT).

METHODS

In this study, 89 subjects with skeletal Class III (49 females, 40 males; 25.45 ± 3.81 years) and 85 subjects with skeletal Class I (45 females, 40 males; 23.95 ± 4.45 years) were collected retrospectively and divided into hyperdivergent, normodivergent and hypodivergent groups. Dolphin software was used to reorient the CBCT images of these subjects. After segmenting 3D object of maxilla from the 3D skull by ProPlan software, Geomagic Studio was used to reconstruct 3D palatal morphology and establish an average 3D palatal morphology for each group. The differences of 3D palatal morphology between different groups were compared by deviation patterns on 3D colored map analysis.

RESULTS

3D colored map analysis showed the posterior part of male's palate was higher and wider than that of female's palate in skeletal Class III subjects. In skeletal Class III subjects, males with hyperdivergent pattern had a higher and narrower palate compared with hypodivergent subjects, while females with hyperdivergent had a higher but not obviously narrower palate compared with hypodivergent subjects. In the similar vertical patterns, skeletal Class III subjects had a flatter but not narrower palate compared with skeletal Class I subjects, along with a smaller palate volume.

CONCLUSIONS

This method allows more intuitive between-group comparisons of the differences of 3D palatal morphology. In skeletal Class III subjects, as the vertical dimension increased, the palate tends to be higher and narrower. Therefore, the influence of vertical patterns on the palatal morphology should be fully considered in the orthodontic and orthognathic treatment of skeletal Class III subjects.

Three-dimensional computed tomographic assessment of mandibular muscles in growing subjects with different vertical facial patterns

Aim

The present study was undertaken to assess the relationship between the mandibular muscles and dentofacial skeletal morphology in children with different underlying vertical facial patterns, using three-dimensional computed tomography (3D-CT).

Method

Thirty children (mean age 12.24 ± 1.57 years) underwent cranial CT examination for diagnostic purposes. 3D-CT images were reconstructed for the evaluation of the cross-sectional size, volume, and spatial orientation of the masseter and medial pterygoid muscles. These muscle parameters were also assessed in relation to the vertical facial pattern, gender and skeleto-dental form.

Results

Significant differences were found in muscular angulation for subjects with different underlying patterns. Greater masseter volumes were associated with increased facial width. Greater intermolar widths were found in brachyfacial subjects, with less acute muscular angulations in relation to horizontal reference lines, compared with dolichofacial subjects. This was also more obvious in the maxillary arch.

Conclusion

Clinicians should note the likely differences in masseter and medial pterygoid orientation and volume in subjects with different underlying vertical facial patterns and that these differences may, in turn, be related to both facial skeletal width and naturally-occurring transverse dental arch dimensions.

Maxillary width and hard palate thickness in men and women with different vertical and sagittal skeletal patterns

INTRODUCTION

The objective of this research was to compare maxillary width and hard palate thickness in men and women with different vertical and sagittal skeletal patterns.

METHODS

A total of 241 adults (93 men and 148 women aged from 18 to 25 years) were divided into male and female groups. Subjects were then separately divided into 3 sagittal skeletal groups and 3 vertical skeletal groups. A lateral cephalogram and a cone-beam computed tomography were taken for each subject. We measured the parameters to make statistical analyses and compared them between the different groups.

RESULTS

Women had smaller craniomaxillofacial bone width and palatal thickness than men. In sagittal groups, maxillary width, maxillary alveolar width, and external temporomandibular joint fossa width in Class II and Class III malocclusion groups were smaller than in the Class I group for both women and men. The internal temporomandibular joint fossa width was the same results in men and women. In vertical groups, palate thickness, maxillary width, and maxillary alveolar width of the high-angle group were smaller than those of the low-angle group, regardless of sex.

CONCLUSIONS

To an extent, maxillary width is correlated with vertical and sagittal skeletal patterns, and insufficient maxillary width would lead to unfavorable skeletal patterns. Differences exist in the morphology of craniomaxillofacial bone between men and women. Therefore, these findings can provide clinicians with references for differential diagnosis and treatment plans.

Comparison of three-dimensional soft-tissue evaluations between skeletal and pseudo-class III malocclusions

The aim of our study was to compare soft tissue measurements with 3D imaging methods in individuals with untreated skeletal and pseudo-Class III malocclusions. The study sample consisted of 75 patients (38 males, 37 females, mean age 12.41 ± 2.35 years) with pseudo- and true skeletal Class III malocclusions and skeletal Class I malocclusions. Soft tissue evaluations of all patients were performed using 3D stereophotogrammetric facial images. In our study, 26 landmarks, 17 linear measurements, 13 angular measurements, and 5 volume measurements were made using the 3dMD Vultus software. The significance was determined to be p < 0.05 in ANOVA, Tukey tests. No significant differences were found among the groups in terms of demographic data (p > 0.05). The skeletal Class I control group had a significantly more extended upper lip and vermillion length as compared to the Class III groups. The soft tissue convexity angle and upper nasal angle were found to be wider in the Class III malocclusion group compared to those in the Class I control group. While the pseudo-Class III group had a significantly lower midface volume, chin volume was significantly higher in the skeletal class group. Upper lip volume was significantly higher in the Class I group. Using 3dMD for guiding clinicians in the differential soft and hard tissue diagnosis of pseudo-Class III malocclusions, differences were revealed in Class I patients in the middle part of the face. In the differential diagnosis of true Class III malocclusions, chin volume was found to be different from that of Class I patients.

Transversal Maxillary Distraction in Patients with Cleft Lip and Palate

OBJECTIVE

The aim of this study is to describe the importance of osteodistraction with transpalatal distractors for treating transversal maxillary hypoplasia in patients with cleft and lip palate.

METHODS

The participants were 17 patients (9 females and 8 males) with cleft lip and palate. Among these, 10 presented unilateral cleft lip and palate, 4 bilateral cleft lip and palate, and 3 cleft palate only.

RESULTS

All patients experienced a satisfactory palatal expansion and crossbite correction. The mean lengthening was 12.7 mm. The average increase of intercanine distance, intermolar distance, maxillary transverse dimension (MTD), facial transverse dimension (FTD) was 12.16, 8.45, 1.77, and 1.67 mm, respectively. The clinical follow-up was 29.7 months (range: 6-61 months).

CONCLUSION

Palatal distraction is a safe and successful alternative for treating maxillary transversal alterations in patients with cleft lip and palate. This technique facilitates the establishment of an adequate transverse dimension of maxillary, and consequently a proper dental occlusion.

Three-dimensional palatal anatomic characteristics' correlation with dermatoglyphic heterogeneity in Angle malocclusions

OBJECTIVES

To assess correlation of dermatoglyphic (DG) pattern with quantitative palatal anatomic parameters measured using three-dimensional (3D) scanning of dental casts and to explore the possibility of utilizing these to predict future occurrence of malocclusion.

MATERIALS AND METHODS

Pretreatment casts of 477 Saudi Arabian patients were divided into Class I, II, and III malocclusion groups. Fingerprints were recorded for all hand digits using a digital biometric device. Maxillary arch analysis was accomplished including intercanine, intermolar distance, palatal height, and palatal area. The results were statistically analyzed.

RESULTS

The mean surface area of the palate was highest in Class II malocclusion. The DG pattern was not significantly associated with the type of malocclusion, except in the instance of the double loop characteristic (P = .05). There was a strong correlation, however, between DG characteristics like simple arch, loop, and double loop and palatal dimensions (intercanine, intermolar distance, and palatal height). Heterogeneity of DG pattern could be reliably used to predict palatal dimensions. Logistic regression revealed that only tented arch, symmetrical, spiral DG patterns and palatal area were significant but weak predictors of Angle malocclusion (P < .05).

CONCLUSIONS

A novel correlation of DG pattern with 3D palatal anatomic characteristics was assessed in different Angle malocclusion classes. Few of the DG characteristics and palatal dimensions showed significant correlations. However, only some of these were significant predictors of Angle malocclusion.

Cranial structure and condylar asymmetry of patients with juvenile idiopathic arthritis: a risky growth pattern

The aim of the study was to evaluate the cephalometric differences and condylar asymmetry between patients with juvenile idiopathic arthritis (JIA) and normal control group. Sixty-two JIA patients with a latero-lateral cephalogram and orthopantomography, seeking for orthodontic therapy, and 62 normal matched subjects were comprised in the study. Cephalometric analysis was used for the evaluation of facial morphology while the method of Habets et al. (J Oral Rehabil 15(5): 465-471, 1988) was used to compare the condyles in orthopantomography. The significance of between-group differences was assessed using the Mann-Whitney test, as appropriate. The results showed a prevalence of the upper maxilla with hypomandibulia (class II), hyperdivergency with short vertical ramus posterior and posterior rotation of the mandible in JIA children (SNB, ANB, NSL/ML, Fh/ML, NL/ML, ArGo, ML P < 0.0001, ML/Oc P < 0.004, ArGo/GoGn P = 0.02, no difference for SNA). The condyles of the JIA group resulted highly asymmetric (P < 0.0001). The growth pattern of JIA patients resulted clearly different from normal subjects. This serious impairment of the cranial growth may be considered as an indicator of the need for early and continuous orthognatodonthic therapy during the entire period of development for all JIA patients, independently from temporomandibular joint signs or symptoms. To this end, it is important that rheumatologists and orthognathodontists set up a multidisciplinary treatment planned to control the side effects of a deranged growing pattern, to strictly avoid any orthodontic therapies that may worsen function and growth, and to promote treatments improving the physiology and biology of the cranial development.

Intra-arch widths: a meta-analysis

OBJECTIVE

To determine and compare the mean values of various intra-arch distances in Class I, Class II division 1 and Class II division 2 patients.

MATERIALS AND METHODS

The search engines PubMed, Embrace and Cochrane were employed to select articles for further study, and the sample thereby selected comprised adult subjects with full permanent dentition, without missing teeth, malformations or previous orthodontic treatment. Only subjects from articles published during the last 10 years were included in the study.

RESULTS

The search located a total of 628 articles regarding arch form. However, only eight articles were chosen for the study. We observed that: the distance between mandibular canines is smaller in Class I than in Class II division 1; mandibular inter-molar distance is similar in Class I and Class II division 1; maxillary inter-canine distance is similar in Class I, Class II division 2 and Class II division 1; maxillary inter-premolar width is greater in Class I than in Class II division 1; and that maxillary inter-molar width is similar in Class I and Class II division 2.

CONCLUSIONS

No statistically significant differences in arch width were found between the different classes analysed (there are only slightly differences between classes), except in the case of mandibular inter-canine width (L3), which was smaller in Class I than in Class II,1, and maxillary inter-premolar width (U4), which was smaller in Class II-I than in Class I.