Ethnic differences in craniofacial and upper spine morphology in children with skeletal Class II malocclusion

Assessing cervical spine and craniofacial morphology in Class II and Class III malocclusions: A geometric morphometric approach

To compare craniofacial and cervical morphology between skeletal Classes II and III applying Geometric Morphometric Methods (GMM). Twenty-six cervical and craniofacial landmarks of 40 Class II and 39 Class III individuals were digitalized on lateral cephalograms. Procrustes ANOVA, generalized Procrustes, principal component analyses, and thin-plate spline function were applied to assess the pattern of shape variation of craniofacial structure and the cervical spine in relation to skeletal classes. Compared with Class III, Class II individuals presented a maxillary protrusion, mandibular retrusion, shorter mandibular corpus, posterior mandibular ramus rotation, anterior cranial base rotation, and a smaller centroid size. Furthermore, a forward and smaller cervical spine were observed. With GMM, the shape and size differences between skeletal classes can be analyzed visually and numerically.

Volumetric assessment of Posterior cranial fossa in a West African population

BACKGROUND AND OBJECTIVES

Posterior fossa pathologies can have potentially devastating outcomes. The volumetric capacity of this fossa, known to have ethnoregional variations, can thus be critical in determining outcomes and intervention measures and approaches to pathologies involving this region. This study aimed to evaluate the normal posterior fossa volumes within the West-African subpopulation.

METHODS

This was a descriptive study of all patients presenting for a cranial imaging study at the study location within a two-year period using a 1.5T MRI of this cranial region. Obtained data included the transverse and anteroposterior diameters, and the height of this fossa and the obtained data was analyzed. P values < 0.05 was statistically significant.

RESULTS

A total of 315 patients were recruited (165 males and 150 females). The average posterior fossa transverse diameter, anteroposterior diameter and height were 108.19 mm, 71.58 mm and 35.53 mm respectively for males, and 105.7 mm, 66.48 mm, and 34.24 mm for females respectively. The average posterior fossa volume for males (292.36 cm3) was significantly higher than for females (252.90 cm3) (p= 0.0038). The highest average posterior fossa volume was between 16-30 years for males and above 75 years for females.

CONCLUSION

Posterior cranial fossa volumes for the West African population is significantly higher than those obtained for other regions. In addition to being beneficial in some posterior fossa space occupying lesions, this larger volume can explain the relative rarity and sexual preferences of some posterior fossa congenital abnormalities like Chiari-1 malformation amongst the West African population.

Epidemiology of Robin sequence in the UK and Ireland: an active surveillance study

BACKGROUND

Birth prevalence of Robin sequence (RS) is commonly reported as 1 case per 8000-14 000 live births. These estimates are based on single-source case ascertainment and may miss infants who did not require hospital admission or those without overt upper airway obstruction at birth.

OBJECTIVES

To identify the true birth prevalence of RS with cleft palate in the UK and Ireland from a population-based birth cohort with high case ascertainment.

METHODS

Active surveillance of RS with cleft palate was carried out in the UK/Ireland using dual sources of case ascertainment: British Paediatric Surveillance Unit (BPSU) reporting card and nationally commissioned cleft services. Clinical data were collected from notifying clinicians at two time points.

RESULTS

173 live-born infants met the surveillance case definition, giving a birth prevalence of 1 case per 5250 live births (19.1 per 100 000 (95% CI 16.2 to 21.9)), and 1:2690 in Scotland. 47% had non-isolated RS, with Stickler syndrome the most common genetic diagnosis (12% RS cases). Birth prevalence derived from the combined data sources was significantly higher than from BPSU surveillance alone.

CONCLUSIONS

Birth prevalence of RS in the UK/Ireland derived from active surveillance is higher than reported by epidemiological studies from several other countries, and from UK-based anomaly registries, but consistent with published retrospective data from Scotland. Dual case ascertainment sources enabled identification of cases with mild or late-onset airway obstruction that were managed without hospital admission. Studies of aetiology and equivalent well-designed epidemiological studies from other populations are needed to investigate the identified geographical variability in birth prevalence.

Three-dimensional phenotype characteristics of skeletal class III malocclusion in adult Chinese: a principal component analysis-based cluster analysis

BACKGROUND

Skeletal class III malocclusion has a diverse and complicated aetiology involving environmental and genetic factors. It is critical to correctly classify and define this malocclusion to be diagnosed and treated on a clinically sound basis. Thus, this study aimed to provide reliable and detailed measurements in a large ethnically homogeneous sample of Chinese adults to generate an adequate phenotypic clustering model to identify and describe the skeletal variation present in skeletal class III malocclusion.

MATERIALS AND METHODS

This is a retrospective cross-sectional study in which 500 pre-treatments cone-beam computed tomography (CBCT) scans of patients with skeletal class III malocclusion (250 males and 250 females) were selected following specific selection criteria. Seventy-six linear, angular, and ratios measurements were three-dimensionally analysed using InVivo 6.0.3 software. These measurements were categorised into 47 skeletal, 18 dentoalveolar, and 11 soft tissue variables. Multivariate reduction methods: principal component analyses and cluster analyses were used to present the most common phenotypic groupings of skeletal class III malocclusion in Han ethnic group of Chinese adults.

RESULTS

The principal component analysis revealed eight principal components accounted for 72.9% of the overall variation of the data produced from the seventy-six variables. The first four principal components accounted for 53.37% of the total variations. They explained the most variation in data and consisted mainly of anteroposterior and vertical skeletal relationships. The cluster analysis identified four phenotypes of skeletal class III malocclusion: C1, 34%; C2, 11.4%; C3, 26.4%; and C4, 28.2%.

CONCLUSION

Based on three-dimensional analyses, four skeletal class III malocclusion distinct phenotypic variations were defined in a large sample of the adult Chinese population, showing the occurrence of phenotypic variation between identified clusters in the same ethnic group. These findings might serve as a foundation for accurate diagnosis and treatment planning of each cluster and future genetic studies to determine the causative gene(s) of each cluster.

A Comparison of Craniofacial Characteristics between Two Different Adult Populations with Class II Malocclusion-A Cross-Sectional Retrospective Study

Simple Summary

One of the most common orthodontic problems, Class II malocclusion, may lead to an increased risk of dentoalveolar trauma, psychosocial issues, and a possible compromised quality of life. Oftentimes clinicians use normative standard values to which each patient is compared to identify deviations from the norm, in order to determine a patient-specific treatment plan. Large inter-individual and inter-ethnic variability, however, is sometimes not considered. In our study, we compared the cephalometric characteristics between two different ethnic groups (South Indian and Vietnamese) with the phenotype of Class II malocclusion in the hope of better understanding this variation and its implications in treatment planning to achieve satisfactory outcomes.

Abstract

The dental, skeletal, and soft-tissue characteristics of a particular malocclusion can differ based on ethnicity, race, age, sex and geographical location with Class II malocclusion being one of the most prevalent malocclusions encountered in orthodontic clinical practice. The broad understanding of the characteristics of vertical skeletal and dental parameters in patients with Class II malocclusion can help clinicians to identify patterns and variations in the expression of this phenotype for better treatment outcomes. Hence, we compared the craniofacial characteristics of skeletal and dental Class II malocclusion traits from Indian and Vietnamese individuals to analyze the vertical skeletal and dental patterns in both population groups. The sample comprised of lateral cephalograms from 100 young adults with Class II malocclusion, of which fifty (25 males and 25 females) were from South India and the other 50 age- and sex-matched adults from Vietnam. The lateral cephalometric radiographs were digitized into anonymous image files and were traced and assessed for 16 vertical skeletal and dental parameters. The ANB angle was greater in males (+1.4 deg; p < 0.001) and females (+1.9 deg; p < 0.001) in the South Indian population. The Vietnamese males had a larger mandibular plane angle, articular angle, anterior facial height and lower anterior facial height compared to the Indian males. The Vietnamese females had larger mandibular plane and articular angles compared to the Indian females. The skeletal class II malocclusion was more severe in the South Indian compared to the Vietnamese adults. The Vietnamese sample showed a generalized tendency towards a more vertical skeletal growth pattern and in males this pattern seemed to be due to the dentoalveolar component. The Vietnamese females showed a tendency towards a vertical growth pattern, but without apparent contribution by the dentoalveolar component.

Treatment effects of functional appliances in children with Class II malocclusion with and without morphologic deviations in the upper spine

INTRODUCTION

This research aimed to compare treatment effects of functional appliances between children with and without morphologic deviations in the upper spine and analyze associations between Atlas dimensions and the short- and long-term treatment effects.

METHODS

Sixty-eight prepubertal or pubertal children (35 boys and 33 girls; mean age, 11.47 ± 1.39 years) treated with Class II functional appliances were included. Lateral cephalograms were taken at pretreatment (T1), postfunctional appliance treatment (T2), and after retention at postpuberty (T3). Upper spine morphology and Atlas dimensions were evaluated at T1. T1-T2 and T1-T3 lateral cephalograms were superimposed using a structural method. Changes in the jaws were compared with multiple linear regression analysis between children with and without deviations in the upper spine. Associations between the changes and Atlas dimensions were analyzed by partial correlation.

RESULTS

Children with morphologic deviations in the upper spine showed significantly more backward rotation of the mandible (P <0.01) and increased inclination of the jaws (P <0.05, P <0.01) from T1-T2 and significantly smaller condylar growth (P <0.01) from T1-T3 compared with children without the deviations. Atlas height was significantly associated with vertical and rotational changes in the mandible (P <0.01) from T1-T2 and condylar growth (P <0.05) from T1-T2 and T1-T3.

CONCLUSIONS

Morphologic deviations in the upper spine and low Atlas height were significantly associated with smaller condylar growth induced by functional appliances in the long term. Upper spine morphology and the Atlas dimension may be valuable in phenotypic differentiation in children with Class II malocclusion for optimal treatment outcome.

Effects of fixed functional appliances with temporary anchorage devices on Class II malocclusion: A systematic review and meta‑analysis

BACKGROUND

The use of fixed functional appliances (FFAs) in conjunction with temporary anchorage devices (TADs) has been proposed to enhance skeletal changes and reduce proclination of the lower incisors.

OBJECTIVES

To systematically investigate the skeletal and dentoalveolar effects of FFAs with TADs on Class II malocclusion in adolescents.

METHODS

Electronic searches of databases and manual searches of references were performed up to August 30, 2020. Randomized controlled trials (RCTs) and clinical controlled trials (CCTs) focusing on adolescent patients treated with FFAs combining TADs were included. The modified Cochrane risk-of-bias tool (R.O.B 2.0) and ROBINS-I (Risk of Bias in Non-randomized Studies-of Interventions) Tool were used to assess the risk of bias in RCTs and CCTs, respectively. Meta-analyses of SNA, SNB, ANB, Co-Gn, SN-MP, the lower and upper incisor inclination changes were performed. Subgroup analyses and sensitivity analyses were conducted based on TAD types, FFA types, record types and types of study designs.

RESULTS

Ten studies were included with a sample size of 281. Meta-analyses revealed significant differences in the changes in SNB (mean difference [MD] 0.67; 95% confidence interval [CI] 0.04-1.29), ANB (MD -1.22, 95% CI -2.04 to -0.39), Co-Gn (MD 1.57; 95% CI 0.22-2.92), inclination of the lower incisors (MD -5.64, 95% CI -7.78 to -3.50)] and inclination of the upper incisors (MD -1.91; 95% CI -3.69 to -0.13). TAD types and FFA types seem to affect the treatment outcome.

CONCLUSIONS

Compared with FFAs alone, FFAs with TADs exhibit superior skeletal effects and reduce the inclination of the lower incisors in the short term; however, the evidence showed moderate to high risk of bias. Registration number CRD42020177611.

A retrospective comparison of dental and skeletal ages between African American, Caucasian, and Hispanic subjects

OBJECTIVE:

To compare dental and skeletal ages among African American (AA), Caucasian (C) and Hispanic (H) subjects (chronological ages 9 to 15-years).

MATERIAL AND METHODS:

A total of 168 subjects (9 to 15 years old) were equally divided into AA, C, and H groups, with an equal number of males and females. Each group was divided equally into 7 chronological age-groups, ranging from 9 to 15 years. Dental age was determined from panoramic radiographs as primary, early mixed, late mixed, or permanent dentition (scored as 1-4). Skeletal age was calculated from hand-wrist radiographs using Fishman's Skeletal Maturation Index (SMI 1-11). One-way analysis of variance and Tukey's test were used to compare skeletal and dental ages among AA, C and H subjects; and AA, C and H subjects in each chronological age-group. The two-sample t-test was used to compare SMI and dental age among females and males.

RESULTS:

Skeletal and dental age were not significantly different between AA, C and H subjects. Mean SMI was higher in females than males; and there were no significant gender differences regarding dental age. Mean SMI and dental age were significantly different among AA, C and H subjects in the 12-year-old and 11-year-old age groups, respectively.

CONCLUSIONS:

Dental and skeletal maturation are fairly similar among AA, C and H subjects (aged 9 to 15 years).

Sub-clustering in skeletal class III malocclusion phenotypes via principal component analysis in a southern European population

The main aim of this study was to generate an adequate sub-phenotypic clustering model of class III skeletal malocclusion in an adult population of southern European origin. The study design was conducted in two phases, a preliminary cross-sectional study and a subsequent discriminatory evaluation by main component and cluster analysis to identify differentiated skeletal sub-groups with differentiated phenotypic characteristics. Radiometric data from 699 adult patients of southern European origin were analyzed in 212 selected subjects affected by class III skeletal malocclusion. The varimax rotation was used with Kaiser normalization, to prevent variables with more explanatory capacity from affecting the rotation. A total of 21,624 radiographic measurements were obtained as part of the cluster model generation, using a total set of 55 skeletal variables for the subsequent analysis of the major component and cluster analyses. Ten main axes were generated representing 92.7% of the total variation. Three main components represented 58.5%, with particular sagittal and vertical variables acting as major descriptors. Post hoc phenotypic clustering retrieved six clusters: C1:9.9%, C2:18.9%, C3:33%, C4:3.77%, C5:16%, and C6:16%. In conclusion, phenotypic variation was found in the southern European skeletal class III population, demonstrating the existence of phenotypic variations between identified clusters in different ethnic groups.

Comparison of cervical vertebral anomalies and sella turcica bridging in different growth stages with various vertical skeletal growth patterns

PURPOSE

To compare cervical vertebral anomalies and sella turcica bridging (STB) in different growth stages in orthodontic patients with different vertical skeletal growth patterns.

METHODS

Lateral cephalometric radiographs (LCR) of 270 patients in the preadolescent, adolescent, or postadolescent periods and having low angle [LA], normal angle [NA], or high-angle [HA] vertical skeletal growth patterns were evaluated retrospectively. STB was visualized using LCRs while evaluating the deficiency of ponticulus posticus (PP) and atlas posterior arch (PAA) associated with the atlas bone. The Pearson chi-square and Fisher's exact tests were used for categorical data and one-way ANOVA for numerical data.

RESULTS

The prevalence of fully calcified PP and STB increased from the preadolescent (PP, 10.0%; STB, 11.1%) to the postadolescent period (PP, 24.4; STB, 21.1%); they did not differ from vertical skeletal growth patterns (p > 0.05). The prevalence of PAA deficiency is significantly higher in individuals with LA (46.7%) than with other angles (NA, 27.8%; HA, 26.7%). The vertical skeletal growth pattern was significantly related to STB in the preadolescent period and PAA in the postadolescent period.

CONCLUSIONS

Different anomalies during different growth periods correlate with the vertical skeletal growth pattern. It will be useful to evaluate a different anomaly according to the relevant growth period.

Dentoskeletal and tooth-size differences between Syrian and Hungarian adolescents with Class II division 1 malocclusion: a retrospective study

Objectives

Malocclusion features differ across various populations and ethnicities. At this time, no data are available regarding the dentofacial differences between Syrian and European adolescents with Class II division 1 malocclusion, which is one of the most frequently treated pathologies in orthodontic practice. The present combined cephalometric and tooth-size study aimed to compare the dentoskeletal and tooth-size characteristics of Syrian and Hungarian adolescents with Class II division 1 malocclusion.

Results

Class II division 1 malocclusion in Hungarian adolescents was a sagittal discrepancy, while in Syrian adolescents, it was a result of excessive vertical development. Syrian adolescents had a significantly excessive vertical development when compared with Hungarian adolescents, regardless of sex (p < 0.01). Hungarian boys had significantly more protruded maxillae (p < 0.001) and less retruded mandibles (p < 0.01) when compared with Syrian boys, while Hungarian girls had significantly shorter mandibles relative to those of Syrian girls (p < 0.01). Syrian girls had significantly more protrusive lower incisors (p < 0.001), accompanied by significantly larger anterior tooth-size ratios when compared to Hungarian girls (p < 0.001). In conclusion, these findings underscore the importance of considering ethnic differences during orthodontic diagnosis and may have implications for optimizing orthodontic treatments in Syrian and Hungarian adolescents with Class II division 1 malocclusion.

Evaluation of growth changes induced by functional appliances in children with Class II malocclusion: Superimposition of lateral cephalograms on stable structures

Objective

To compare short- and long-term dentoalveolar, skeletal, and rotational changes evaluated by Björk’s structural method of superimposition between children with Class II malocclusion treated by functional appliances and untreated matched controls.

Methods

Seventy-nine prepubertal or pubertal children (mean age, 11.57 ± 1.40 years) with Class II malocclusion were included. Thirty-four children were treated using an activator with a high-pull headgear (Z-activator), while 28 were treated using an activator without a headgear (E-activator). Seventeen untreated children were included as controls. Lateral cephalograms were obtained before treatment (T1), after functional appliance treatment (T2), and after retention in the postpubertal phase (T3). Changes from T1 to T2 and T1 to T3 were compared between the treated groups and control group using multiple linear regression analysis.

Results

Relative to the findings in the control group at T2, the sagittal jaw relationship (subspinale-nasion-pogonion, p < 0.001), maxillary prognathism (sella-nasion-subspinale, p < 0.05), and condylar growth (p < 0.001) exhibited significant improvements in the Z- and E-activator groups, which also showed a significantly increased maxillary incisor retraction (p < 0.001) and decreased overjet (p < 0.001). Only the E-activator group exhibited significant backward rotation of the maxilla at T2 (p < 0.01). The improvements in the sagittal jaw relationship (p < 0.01) and dental relationship (p < 0.001) remained significant at T3. Condylar growth and jaw rotations were not significant at T3.

Conclusions

Functional appliance treatment in children with Class II malocclusion can significantly improve the sagittal jaw relationship and dental relationships in the long term.

Upper cervical spine abnormalities as a radiographic index in the diagnosis and treatment of temporomandibular disorders

OBJECTIVE

The aim of this study was to investigate the clinical characteristics and treatment outcomes of patients with temporomandibular disorders (TMD) according to the presence of upper cervical spine abnormalities and craniofacial morphology.

STUDY DESIGN

Clinical examinations were conducted on 43 patients with TMD. Upper cervical spine characteristics (fusion, posterior arch deficiency [PAD], and craniofacial morphology) reflecting head-and-neck posture were evaluated on lateral cephalograms. Condylar bone changes in the temporomandibular joint were evaluated by using cone beam computed tomography. Clinical characteristics and treatment outcomes after 1 year of conservative therapy were statistically analyzed between groups, according to the presence of upper cervical spine abnormalities.

RESULTS

Pain on neck muscle palpation was more frequent in patients with cervical fusion (P = .019) and with either fusion or PAD (P = .004) before treatment. Patients with PAD had smaller comfortable mouth opening ranges compared with those without the deficiency (P = .044) before treatment and smaller comfortable (P = .020) and maximum (P = .021) mouth opening ranges after treatment. Patients with PAD also had mouth opening limitation (P = .028) and pain on masticatory muscle palpation (P = .014) more frequently after treatment compared with patients without the deficiency.

CONCLUSIONS

Associations exist between upper cervical spine characteristics and treatment outcomes in patients with TMD, suggesting such parameters as a possible radiographic index in TMD diagnosis and treatment.

Subclustering in Skeletal Class III Phenotypes of Different Ethnic Origins: A Systematic Review

OBJECTIVE

We aimed to systematically review articles investigating the efficiency of the clustering of skeletal class III malocclusion phenotypic subtypes of different ethnic origins as a diagnostic tool.

METHODS

The review protocol was structured in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses statement and registered in Prospero (CRD42016053865). A survey of articles published up to March 2018 investigating the identification of different subgroups of skeletal class III malocclusion via cluster analysis was performed using 11 electronic databases. Any type of study design that addressed the classification of subclusters of class III malocclusion was considered. The Newcastle-Ottawa scale for cohort and cross-sectional (modified) studies was used for quality assessment.

RESULTS

The final selection included 7 studies that met all the criteria for eligibility (% overall agreement 0.889, free marginal kappa 0.778). All studies identified at least 3 different types of class III clusters (ranging from 3 to 14 clusters; the total variation of the prevalence of each cluster ranged from 0.2% to 36.0%). The main shared variables used to describe the more prevalent clusters in the studies included were vertical measurements (Ar-Go-Me: 117.51°-135.8°); sagittal measurements: maxilla (SNA: 75.3°-82.95°), mandible (SNB: 77.03°-85.0°). With regard to ethnicity, a mean number of 8.5 and 3.5 clusters of class III were retrieved for Asian and Caucasian population, respectively.

CONCLUSIONS

The total number of clusters identified varied from 3 to 14 to explain all the variability in the phenotype class III malocclusions. Although each extreme may be too simple or complex to facilitate an exhaustive but useful classification for clinical use, a classification system including 4 to 7 clusters may prove to be efficient for clinical use in conjunction with complete and meticulous subgrouping.

CLINICAL SIGNIFICANCE

The identification and description of a subclustering classification system may constitute an additional step toward more precise orthodontic/orthopedic diagnosis and treatment of skeletal class III malocclusion.