CBCT imaging vs conventional radiography

Detection and classification of mandibular fractures in panoramic radiography using artificial intelligence

OBJECTIVES

This study evaluated the performance of the YOLOv5 deep learning model in detecting different mandibular fracture types in panoramic images.

METHODS

The dataset of panoramic radiographs with mandibular fractures was divided into training, validation, and testing sets, with 60%, 20%, and 20% of the images, respectively. An equal number of control images without fractures were also distributed among the datasets. The YOLOv5 algorithm was trained to detect six mandibular fracture types based on the anatomical location including symphysis, body, angle, ramus, condylar neck, and condylar head. Performance metrics of accuracy, precision, sensitivity (recall), specificity, dice coefficient (F1 score), and area under the curve (AUC) were calculated for each class.

RESULTS

A total of 498 panoramic images containing 673 fractures were collected. The accuracy was highest in detecting body (96.21%) and symphysis (95.87%), and was lowest in angle (90.51%) fractures. The highest and lowest precision values were observed in detecting symphysis (95.45%) and condylar head (63.16%) fractures, respectively. The sensitivity was highest in the body (96.67%) fractures and was lowest in the condylar head (80.00%) and condylar neck (81.25%) fractures. The highest specificity was noted in symphysis (98.96%), body (96.08%), and ramus (96.04%) fractures, respectively. The dice coefficient and AUC were highest in detecting body fractures (0.921 and 0.942, respectively), and were lowest in detecting condylar head fractures (0.706 and 0.812, respectively).

CONCLUSION

The trained algorithm achieved promising results in detecting most fracture types, particularly in body and symphysis regions indicating machine learning potential as a diagnostic aid for clinicians.

Morphological evaluation of maxillary arch in unilateral buccally and palatally impacted canines: a cone-beam computed tomography (CBCT)-based study in Northern Iran

Purpose

This study investigated the association between the maxillary impacted canines' position and the maxilla's morphological features in an Iranian population based on cone-beam computed tomography (CBCT) images.

Material and methods

In this cross-sectional descriptive-analytical study, 47 CBCT images of unilateral buccally impacted maxillary canines and 47 CBCT images of unilateral palatally impacted maxillary canines were examined. Several morphological variables were compared between the impacted and non-impacted sides, and between the buccal and palatal impaction types.

Results

Gender and age were not significantly associated with the canine impaction type. The alveolar bone height at the impacted side was significantly greater in the buccally impacted group than in the palatally impacted group (p = 0.016). In a comparison of the impacted and non-impacted sides, all variables of alveolar bone thickness at depth of 2 mm, maxillary arch width, and palatal volume had significantly smaller values in the impacted side in both buccally and palatally impacted groups (p < 0.05). The alveolar bone was significantly thicker at the depth of 10 mm in the impacted side of the buccal group (p = 0.024). The maxillary arch perimeter was significantly smaller in the impacted side of the buccal group (p = 0.008). The palatal depth did not significantly differ between the groups.

Conclusion

Among the studied variables, the alveolar bone thickness showed contrary results at different depths. The palatal volume and maxillary arch width were significantly smaller on the impacted side in both buccal and palatal groups, and the arch perimeter showed the same results only in the buccal group.

Three-dimensional measurement and analysis of mandibular characteristics in subjects with impacted mandibular second molars

OBJECTIVE

To investigate the morphological characteristics of the mandible in subjects with impacted mandibular second molars by measuring and analysing the mandible in three dimensions.

SETTING AND SAMPLE POPULATION

In this retrospective study, the data of a total of 52 609 subjects who underwent cone-beam computed tomography (CBCT) for diagnosis and treatment were reviewed. According to the inclusion and exclusion criteria, 183 subjects with impacted mandibular second molars and 176 age- and sex-matched controls were included.

METHODS

A retrospective case-control study was designed. The 183 subjects were divided into two groups: group 1 (G1) comprised 120 patients with unilaterally impacted mandibular second molars, and group 2 (G2) comprised 63 patients with bilaterally impacted mandibular second molars. Group 3 (G3) contained 176 age- and sex-matched controls. The mandible was reconstructed with nineteen landmarks using Mimics software. Twelve linear lengths and 3 angles were measured.

RESULTS

The bilateral germination gap, mandibular body width and gonion width in G1 were significantly lower than those in G3 (P < .05), while the gnathion angle and first molar width values in G1 were significantly higher than those in G3 (P < .05). The results in G2 were similar to those in G1, but the differences between G2 and G3 were greater than those between G1 and G3. There were no significant differences in the other measurements among the groups.

CONCLUSION

The mandibles of the subjects with impacted second molars were constricted in terms of the sagittal length and transverse width.

[Three-dimensional analysis of the mandible with impacted mandibular second molar]

OBJECTIVE

To study the developmental and morphological characteristics of the mandible in patients with impacted mandibular second molar and to predict the possible trend of mandibular development via three-dimensional (3D) measurement and analysis.

METHODS

A total of 88 cases of impacted group and 88 cases of control group were screened out. 3D measurements were performed by using Mimics software. A total of 23 landmark points and 17 measurements were determined. The measurements were analyzed by t-test.

RESULTS

The mandible length, the space between the first molars, the space between mandibular angles, and the width between the first molars in the impacted group were lower than those in the control group (P<0.05). Moreover, the value of the submandibular angle was higher than that in the control group (P<0.05).

CONCLUSIONS

The impacted mandible of patients with mandibular second molar showed lack of sagittal and width development, and the impacted mandibular second molar was a manifestation of its degeneration.