Quantitative analysis of mandibular cortical morphology using artificial intelligence-based computer assisted diagnosis for panoramic radiography on underlying diseases and dental status in women over 20 years of age

Background/purpose

Recently, an artificial intelligence-based computer-assisted diagnosis (AI-CAD) for panoramic radiography was developed to scan the inferior margin of the mandible and automatically evaluate mandibular cortical morphology. The aim of this study was to analyze quantitatively the mandibular cortical morphology using the AI-CAD, especially focusing on underlying diseases and dental status in women over 20 years of age.

Materials and methods

419 patients in women over 20 years of age who underwent panoramic radiography were included in this study. The mandibular cortical morphology was analyzed with an AI-CAD that evaluated the degree of deformation of the mandibular inferior cortex (MIC) and mandibular cortical index (MCI) automatically. Those were analyzed in relation to underlying diseases, such as diabetes, hypertension, dyslipidemia, rheumatism and osteoporosis, and dental status, such as the number of teeth present in the maxilla and mandible.

Results

The degree of deformation of MIC in women under 51 years of age (21-50 years; n = 229, 16.0 ± 12.7) was significantly lower than those of over 50 years of age (51-90 years; n = 190, 45.1 ± 23.0), and the MCI was a significant difference for the different age group. Regarding the degree of deformation of MIC and MCI in women over 50 years of age, osteoporosis and number of total teeth present in the maxilla and mandible were significant differences.

Conclusion

The results of this study indicated that the mandibular cortical morphology using the AI-CAD is significantly related to osteoporosis and dental status in women over 50 years of age.

Evaluation of cortical and trabecular bone structure of the mandible in patients using L-Thyroxine

BACKGROUND

Long-term use of L-Thyroxine (LT4), the synthetic thyroxine hormone used for thyroid hormone replacement therapy, is an important risk factor for osteoporosis. The aim of this study was to investigate the differences between mandibular cortical index (MCI) and trabecular bone fractal dimension (FD) values on panoramic radiographs of patients using LT4 and control subjects.

METHODS

A total of 142 female patients, 71 cases and 71 controls, were analyzed in the study. Ages were matched in case and control groups and the mean age was 36.6 ± 8.2 (18 to 50) years. MCI consisting of C1 (Normal Mandibular Cortex), C2 (Moderately Resorbed Mandibular Cortex) and, C3 (Severely Resorbed Cortex) scores was determined for case and control groups. Fractal analysis was performed using ImageJ on selected regions of interest from the gonial and interdental regions. The box-count method was used to calculate FD values. Wilcoxon signed-rank test, Mann-Whitney U test, and Spearman correlation analysis were applied to compare the measurements. Statistical significance of differences was established at P < 0.05 level.

RESULTS

FD values did not show statistically significant differences between case and control groups (p > 0.05). The mean FD in the right gonial region was 1.38 ± 0.07 in the case group and 1.38 ± 0.08 in the control group (p = 0.715). The mean FD in the right interdental region was 1.37 ± 0.06 in the cases and 1.36 ± 0.06 in the control group (p = 0.373). The mean FD in the left gonial region was 1.39 ± 0.07 in the cases and 1.39 ± 0.07 in the control group (p = 0.865). The mean FD in the left interdental region is 1.37 ± 0.06 in the cases and 1.38 ± 0.05 in the control group (p = 0.369). The most common MCI score was C1, with 62% in the cases and 83.1% in the control group. MCI scores showed a statistically significant difference between cases and controls (p = 0.016, p < 0.05). While the C2 score was higher in the cases, the C1 score was higher in the controls.

CONCLUSIONS

LT4 use was not associated with the FD of mandibular trabecular bone, but was associated with MCI values of cortical bone. Further studies on larger samples with different imaging modalities and image processing methods are needed.

General and local predictors of mandibular cortical bone morphology in adult females and males: the seventh survey of the Tromsø Study

OBJECTIVES

To analyze factors predicting mandibular cortical width (MCW) and mandibular cortical index (MCI) in adult females and males.

MATERIAL AND METHODS

Data on 427 females and 335 males aged 40-84 from The Tromsø study: Tromsø7 were used. T-score, age, menopausal status (for females), remaining teeth, and periodontal status were analyzed in linear and logistic regression analyses as predictors of MCW and MCI, respectively.

RESULTS

T-score, age, and the number of remaining teeth significantly predicted MCW in females but not males. Standardized β coefficients were 0.286, -0.231, and 0.131, respectively. The linear regression model explained 24% of MCW variation in females. MCI in females was significantly predicted by T-score, age, and remaining teeth with the Wald values of 9.65, 6.17, and 5.83, respectively. The logistic regression model explained 16.3-23% of the variation in MCI in females. In males, T-score was the only significant predictor of the eroded cortex, and the logistic model explained only 4.3-5.8% of the variation in MCI.

CONCLUSIONS

The T-score demonstrated a stronger relationship with MCW and MCI than other factors in females, which supports the usefulness of those indices for osteoporosis screening. Conversely, the T-score exhibited no association with MCW and remained the only significant predictor of MCI in males, yet to a lesser extent than in females.

CLINICAL RELEVANCE

Understanding factors affecting mandibular cortical morphology is essential for further investigations of MCW and MCI usefulness for osteoporosis screening in females and males.

Association of gonial angle with morphology and bone mineral content of the body of the adult human mandible with complete permanent dentition

We investigated the differences between 2 gonial angle (GA) size groups with respect to the morphometry and quantitative bone mineral content (QBMC) of mandibles with all teeth erupted and normal occlusion. We used 19 dried mandibles that were obtained from an Indian population and stored in our department. These mandibles were at Hellman's developmental dental stage VA and were divided into low gonial angle (LGA) (GA ≤ 120°; 8 specimens; 16 sides) and high gonial angle (HGA) (GA ≥ 125°; 11 specimens; 22 sides) groups. After lateral radiography of the mandibles using a titanium step wedge, linear measurements and the QBMC were determined, on hard copies and digital images, respectively. The age and sex of the cadavers to which the specimens belonged were unknown. The mandibular cortical width (MCW) and the antegonial notch depth of the LGA group were significantly larger than those of the HGA group. No significant difference was found in the distribution of the 3 categories of mandibular cortical index (MCI) or in cortical and trabecular bone mineral contents (CBMC and TBMC). The GA size was negatively and moderately associated with the MCW and the mandibular cortical width on the point AG (MCWAG), but was not significantly associated with either variable for CBMC and TBMC. These results suggested that the GA size of these stage-VA mandibles influenced changes in the width of inferior cortex and morphology of antegonial notch. The GA size did not influence QBMC under the mental foramen of the mandible and had negative associations with the MCW and MCWAG.

A Radiographic comparison of mandibular bone quality in pre- and post-menopausal women in Indian population

Aim and Objectives:

The main objective of the study is to assess mandibular bone changes in pre and postmenopausal women with chronic generalized periodontitis using different radiomorphometric indices, mandibular cortical index (MCI), mental index (MI), and panoramic mandibular index (PMI) in Indian population.

Materials and Methods:

Panoramic radiographs of 60 patients visiting the Department of Periodontology were taken and divided in two groups - pre and post-menopausal. Detailed medical and menopausal history was recorded for each patient. All the radiographs were assessed for PMI, MI and MCI and presence of periodontitis. The destructive periodontitis was assessed as distance from the cementoenamel junction to the alveolar crest greater than 2mm.

Statistical Analysis:

Student-t test was applied to compare mean values of MI and PMI. Intra and inter group comparison of MCI were made using chi-square test. Correlation of age and MI and PMI was found by Pearson’s correlation coefficient.

Results:

MCI, PMI and MI were related to the menopausal status. Patients with C3 category were seen only in post-menopausal group after 54 years of age. Higher mean values for both MI (p<0.05) and PMI (p<0.05) were observed in pre-menopausal group with statistically significant differences. MI showed negative correlation with age in both the groups; however PMI was positively correlated with age.

Conclusions:

Radiomorphometric indices could be used by general dentists after a little training to detect post-menopausal women at higher risk of osteoporosis.

Evaluating mandibular cortical index quantitatively

OBJECTIVES

The aim was to assess whether Fractal Dimension and Lacunarity analysis can discriminate patients having different mandibular cortical shape.

METHODS

Panoramic radiographs of 52 patients were evaluated for mandibular cortical index. Weighted Kappa between the observations were varying between 0.718-0.805. These radiographs were scanned and converted to binary images. Fractal Dimension and Lacunarity were calculated from the regions where best represents the cortical morphology.

RESULTS

It was found that there were statistically significant difference between the Fractal Dimension and Lacunarity of radiographs which were classified as having Cl 1 and Cl 2 (Fractal Dimension P:0.000; Lacunarity P:0.003); and Cl 1 and Cl 3 cortical morphology (Fractal Dimension P:0.008; Lacunarity P:0.001); but there was no statistically significant difference between Fractal Dimension and Lacunarity of radiographs which were classified as having Cl 2 and Cl 3 cortical morphology (Fractal Dimension P:1.000; Lacunarity P:0.758).

CONCLUSIONS

FD and L can differentiate Cl 1 mandibular cortical shape from both Cl 2 and Cl 3 mandibular cortical shape but cannot differentiate Cl 2 from Cl 3 mandibular cortical shape on panoramic radiographs.