Reliability of overbite depth indicator (ODI) and anteroposterior dysplasia indicator (APDI) in the assessment of different vertical and sagittal dental malocclusions: a receiver operating characteristic (ROC) analysis

Ceph-Net: automatic detection of cephalometric landmarks on scanned lateral cephalograms from children and adolescents using an attention-based stacked regression network

BACKGROUND

The success of cephalometric analysis depends on the accurate detection of cephalometric landmarks on scanned lateral cephalograms. However, manual cephalometric analysis is time-consuming and can cause inter- and intra-observer variability. The purpose of this study was to automatically detect cephalometric landmarks on scanned lateral cephalograms with low contrast and resolution using an attention-based stacked regression network (Ceph-Net).

METHODS

The main body of Ceph-Net compromised stacked fully convolutional networks (FCN) which progressively refined the detection of cephalometric landmarks on each FCN. By embedding dual attention and multi-path convolution modules in Ceph-Net, the network learned local and global context and semantic relationships between cephalometric landmarks. Additionally, the intermediate deep supervision in each FCN further boosted the training stability and the detection performance of cephalometric landmarks.

RESULTS

Ceph-Net showed a superior detection performance in mean radial error and successful detection rate, including accuracy improvements in cephalometric landmark detection located in low-contrast soft tissues compared with other detection networks. Moreover, Ceph-Net presented superior detection performance on the test dataset split by age from 8 to 16 years old.

CONCLUSIONS

Ceph-Net demonstrated an automatic and superior detection of cephalometric landmarks by successfully learning local and global context and semantic relationships between cephalometric landmarks in scanned lateral cephalograms with low contrast and resolutions.

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.

Efficiency of ODI and APDI of Kim's cephalometric analysis in a Latin American population with skeletal open bite

Objective:

The objective of this research was to demonstrate the efficiency of the overbite depth indicator (ODI) and the anteroposterior dysplasia indicator (APDI) from Kim’s cephalometric analysis, regarding the determination of the vertical and sagittal patterns of Latin American individuals.

Methods:

Two hundred lateral cephalometric radiographs were selected and divided into four study groups, with 50 radiographs each, for carrying out a cross-sectional study. The control group included radiographs of balanced individuals, and the other three groups had lateral cephalometric radiographs of subjects with Class I, II and III malocclusions and with skeletal open bite. After the pilot test was performed to calibrate the investigator, the ODI and APDI were measured. Descriptive statistics were performed and the one-way ANOVA with post-hoc Tukey HSD, or Kruskal-Wallis and Mann-Whitney U-test were used. Also a multiple linear regression was employed.

Results:

Statistically significant differences were found for the ODI of all groups (p< 0.001), except between Class I group (65.87 ± 4.26) and Class II open bite group (67.19 ± 3.58), both with similar values to each other. For APDI, statistically significant differences were also found for all groups (p< 0.001). However, no statistically significant differences were found between the balanced group (83.18 ± 1.71) and Class I group with skeletal open bite (81.78 ± 2.69).

Conclusions:

ODI and APDI are reliable indicators to evaluate the sagittal and vertical patterns of an individual, demonstrating their efficiency when a Latin American population was evaluated.

Overbite depth indicator and anteroposterior dysplasia indicator cephalometric norms for African Americans

OBJECTIVES

To examine normal Overbite Depth Indicator (ODI) and Anteroposterior Dysplasia Indicator (APDI) values in African Americans and to compare them with mean values from white patients. Secondary aims were to compare mean ODI and APDI values among different age, gender, and combined age-gender groups in African American patients.

MATERIALS AND METHODS

Lateral cephalometric radiographs of 160 African American patients (97 boys and 63 girls; age, 7 to 14 years) with normal occlusion and no history of orthodontic treatment were collected from the Bolton-Brush Growth Center. Cephalometric images were hand traced, and ODI and APDI values were assessed. Two-sample t tests were used to compare mean ODI and APDI values between African American and white patients; and between male and female African American patients. One-way analysis of variance, followed by the Tukey test, was used to compare mean ODI and APDI values among different African American age and combined age-gender groups.

RESULTS

Mean ODI and APDI values were significantly lower (P < .0001) in African American than white patients with normal occlusion and no history of orthodontic treatment. Mean ODI and APDI values increased with age in African American patients, and there were no significant gender differences.

CONCLUSIONS

The mean ODI and APDI values in 7- to 14-year-old African Americans with normal occlusion and no history of orthodontic treatment were 70.9° and 78.1°, respectively, and were significantly lower than the mean values for white patients in the same age range.