| Abstract|| |
Aim: The aim of this study is to validate the Fernanda Angelieri classification method for the individual assessment of mid-palatal suture among Indian children using multi-slice computed tomography (CT) with respect to clinical application in rapid maxillary expansion. Material and Methods: Present study was conducted utilizing 760 existing head and neck CT image records. CT images were stratified into three categories based on growth spurts: Group I – 6–10 years (n = 210), Group II – 11–14 years (n = 270), and Group III – 15–18 years (n = 280). The CT images were analyzed for stages of mid-palatal suture maturation, according to age and sex. The recorded data were subjected for statistical analysis. Results: Indian children, up to age of 10 years, were distributed in stage A and B. After 11 years, up to 14 years girls showed varied distribution and spread equally among stage B, C, and D. After 15 years, more number of girls were distributed in stage D and E, whereas boys remained distributed variedly in stage B, C, and D. Mid- palatal suture maturational stages correlated to chronological age among both the genders using Fisher exact test and expected contingency table showed statistically significant variation among both the gender independently and collectively (P < 0.001). Conclusion: Cone beam computed tomography (CBCT)-based prediction of stages of mid- palatal suture maturation by Fernanda Angelieri is valid among the Indian population. During treatment plan of maxillary expansion among children above 10 years, it is better to have a diagnostic CBCT image analysis of mid-palate suture for predicable prognosis.
Keywords: Age, CT, rapid maxillary expansion, stages
|How to cite this article:|
Chanchala H P, Nandlal B, Murthy N, Shanbhog R. Validation of cone beam computed tomography-based classification method for individual assessment of mid-palatal suture with respect to clinical application among Indian children. Indian J Dent Res 2020;31:85-90
|How to cite this URL:|
Chanchala H P, Nandlal B, Murthy N, Shanbhog R. Validation of cone beam computed tomography-based classification method for individual assessment of mid-palatal suture with respect to clinical application among Indian children. Indian J Dent Res [serial online] 2020 [cited 2021 May 11];31:85-90. Available from: https://www.ijdr.in/text.asp?2020/31/1/85/281816
| Introduction|| |
Angell in 1860 introduced the concept that the maxilla can be expanded by opening the mid-palatal suture. Later, the landmark work of Haas (1961) made rapid maxillary expansion (RME) routine in orthodontic practices. RME has been used in orthodontic practice with the objective to expand the maxilla by separating the mid-palatal and the circum maxillary sutural system. The mid- palatal suture has been described as an end-to-end type of suture with characteristic changes in its morphology during growth.,, The start and the advance of fusion of the mid- palatal suture vary greatly with age and sex., So, understanding individual variability in the fusion of the mid- palatal suture is essential in identifying suitable cases of RME.
To diagnose individual variability in the fusion of the mid- palatal suture, Revelo and Fishman in 1994 proposed assessment of the mid- palatal suture morphology with occlusal radiographs before RME therapy. However, occlusal radiographs are not reliable for analyzing mid- palatal suture morphology because the vomer and the structures of the external nose overlay the mid- palatal area and thus might lead to false radiographic interpretations of mid- palatal suture fusion. Hahn in an animal study proposed multi-slice computed tomography (CT) imaging as an alternative to occlusal radiographs to access the maturation of the mid- palatal suture. In 2013, Fernanda Angelieri et al. presented a novel classification method for the individual assessment of mid-palatal suture morphology using cone beam computed tomography (CBCT) on Caucasian population.
The aim of the present study was to validate the above said Fernanda Angelieri classification method for the individual assessment of mid-palatal suture among Indian children using the multi-slice CT with respect to clinical application in RME.
| Materials and Methods|| |
The procedure protocol was reviewed and approved by the Institutional Research Ethics Committee (JSSDCH/PGS/ETHICAL/2015-16/09).
Study design and location
Present study was an in vitro cross-sectional validation type and was conducted utilizing existing CT image records from Radiology department of the medical college hospital.
Sample size determination and collection
The sample size was calculated based on previous study results. With power of the study at 90% and 10% allowable error, the sample size was found to be 743. The CT images for present study were collected from the existing records of the patients who had been subjected to CT scan of the head and neck (Phillips Ingenuity CT, 128 Slice, Slice width-SW 1 mm) for various clinical purposes between the time frame of October 2014 and December 2016 (total CT images: 13,863). After scrutinizing for selection criteria [Table 1], a total of 760 images were selected for final data collection [Figure 1].
Allocation of groups
The selected 760 CT images were further stratified into three categories on the basis of growth spurts as follows:
- Group I – 6–10 years (n = 210)
- Group II – 11–14 years (n = 270)
- Group III – 15–18 years (n = 280).
Standardization and selection of the images for sutural assessment
The images were viewed using the Radiant Dicom Viewer software 3.4.1 Version, 64 bit Medixant Poznan, Poland. The images were standardized based on three planes; blue line corresponding to coronal plane allows the consistent assessments of the mid- palatal sutures, green line corresponding to sagittal plane is a fixed point, and axial plane in orange indicates the position of the axial planes which has to be set through the center of the supero-inferior dimension of the hard palate [Figure 2]. From standardized images, axial central cross-sectional slices were used for assessment of the mid- palatal suture maturation. They were selected by taking the most central cross-sectional slices through the mid-portion of the trabecular bone of the hard palate, bordered by the oral cavity and the floor of the nasal cavity in the mid-sagittal section in which the mid- palatal suture showed the most advanced signs of maturation.
|Figure 2: Computed tomography showing standardization of images based on three planes: coronal plane is a blue line to allow the consistent assessments of the mid-palatal sutures, sagittal planes are marked green at a fixed point, and axial plane in orange that indicates the position of the axial planes |
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Analysis of computed tomography images
The selected axial central cross-sectional slices were coded and arranged in a PowerPoint presentation (Microsoft Office 2007), sequentially, and were displayed on a high-definition computer monitor in a darkened room for analysis. Each image was then analyzed and classified according to Fernanda Angelieri et al. classification method for the individual assessment of mid-palatal suture morphology [Table 2] by two independent calibrated subject experts. The two subject experts classified all images (without changing contrast or brightness) blindly in the same room under dim light conditions, using the same high-definition monitor individually. In case of discrepancy, reexamination was done and findings were reconfirmed. The collected data were then transferred to Excel and subjected for statistical analysis.
Calibration of subject experts
Inter- and intra-examiner calibration of subject experts was performed in two stages, first stage using randomly selected 10 CT images without changing contrast or brightness. For reference, the definitions and figures of the maturational stages of the mid- palatal suture were shown in the PowerPoint presentation with a black background, in which both subject experts openly classified the mid- palatal suture, and queries if any were discussed and clarified. In second stage, obtained results were further validated using 30 randomly selected images to represent all maturational stages of the mid- palatal suture. A second viewing session and reclassification by the same experts was done 2 days later in the same way after random rearrangement of the same images.
Intra-examiner and inter-examiner agreement was evaluated using kappa coefficient. Nonparametric tests and Fisher exact test were applied to compare between the groups using the SPSS version 23.0 statistical package (SPSS Inc., Chicago, IL, USA).
| Results|| |
The intra-examiner and inter-examiner reproducibility weighed demonstrated considerable agreement, with 0.83 and 0.78 kappa coefficient values, respectively.
Distribution of children according to mid-palatal suture maturational stages conferring to gender is presented in [Table 3], [Table 4], [Table 5]. The result showed a great variability in distribution of the maturational stages of the mid- palatal suture relating gender and chronologic ages.
|Table 3: Distribution of 6-10 years children according to mid-palatal suture maturational stages|
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|Table 4: Distribution of 11-14 years children according to mid-palatal suture maturational stages|
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|Table 5: Distribution of 15-18 years children according to mid-palatal suture maturational stages|
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Girls in the age group of 6–10 years were distributed predominantly in the stage A (23.8%) followed by stage B and in stage C. Girls in the age group 11–14 years were predominantly distributed in the stage D (19.2%) followed by stage B and C (14.7%). About 15–18-year-old girls were distributed in majority in the stage D and E (17.8% and 14.2%).
Boys in the age group of 6–10 years were distributed significantly in the stage A (42.8%) followed by stage B, and none of them had approached stage C in comparison to a few girls of the same age group who had approached stage C. Between the age group 11–14 years, higher number of boys were distributed in stage B (22.1%) followed by stage A, C, and D. The boys of age 15–18 years had approached stage B (17.8%) in majority and an equal distribution observed between stage C and D [Graphs 1] and [Graphs 2]. Irrespective of the gender, in the age group of 15–18 years, there was no evidence of stage A.
Mid- palatal suture maturational stages were further correlated to chronological age among both the genders using Fisher exact test. Expected contingency table showed statistically significant P values among both genders independently and collectively (P < 0.001) [Table 6].
|Table 6: Expected contingency table correlating mid-palatal suture maturational stages with chronological age|
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| Discussion|| |
The present study was conducted using 760 CT images (collected from the existing records) of Indian children to validate Fernanda Angelieri classification method for the individual assessment of mid-palatal suture.
Success of maxillary expansion therapy greatly depends upon the amount of fusion of mid-palatal suture in an individual. However, fusion of mid- palatal suture varies greatly with age and gender., To diagnose this individual variability in the fusion of the mid- palatal suture, in 2013, Fernanda Angelieri et al. presented a novel classification method for the individual assessment of mid-palatal suture morphology using CBCT on Caucasian population. To understand possible interethnic variability of mid- palatal suture maturation, a validation is needed for Indian population.
Present study results in comparison with Fernanda Angelieri study showed that Indian girls between ages 6 and 10 years were distributed more in stage A in contrast to Caucasian (Fernanda Angelieri 2013) (distributed more in stage B) which indicates maturational lag in Indian girls up to age 10 compared to Caucasian. After 11 years of age, the palatal maturational stages were found to be distributed in almost similar fashion in both Indian and Caucasian girls up till age 18. Among boys between age 11 and 14 years both Indians and Caucasians showed similar distribution of maturational stages. However, comparison of boys between age 6–10 and 15–18 years was unattainable due to the less sample size of Fernanda Angelieri 2013 study. The present study-expected contingency table of Fisher exact test also showed statistically significant P values among both the gender independently and collectively (P < 0.001) deducing that there is difference in maturational stages between genders across chronological age among Indian children. After the age of 10, the palatal maturation among girls preceded compared to the boys. Irrespective of the gender, stage A was not observed after 15 years. These findings were in accordance with the previous study by Fernanda Angelieri et al. Overall, the variability observed in the distribution of the maturational stages considering that both age and gender were found in accordance with Fernanda Angelieri et al. study results.
Clinical application of CT-based individual assessment of mid-palatal suture morphology warrants a thorough understanding of CT image appearance and its relation to morphologic status. Correlation of chronological age (irrespective of gender), histological findings of suture, and Fernanda Angelieri et al. stages showed, the “infantile” stage (up to 10 years of age), the suture was broad and smooth (stage A of Fernanda Angelieri), whereas in the “juvenile” stage (from 10 to 13 years), it had developed into a more typical squamous suture with overlapping sections (stage B of Fernanda Angelieri). During the “adolescent” stage (13 and 14 years of age), the suture was wavier with increased inter-digitation (stage C of Fernanda Angelieri). Finally, the “adult” stage of the suture (>15 years) was noted synostoses and numerous bony bridge formations across the suture (stage D and E of Fernanda Angelieri)., The above said correlation fail's when age along with gender is considered, as a significant variation was observed in the distribution of the maturational stages. Hence, predicting accurate clinical guidelines for treatment timing is not available.,, This might be the prime reason for failures of RME in adolescent and young adults. This explains the importance for determining the developmental status of the suture during growth using CT or CBCT before maxillary expansion.
Trying to correlate CT-based maturational classification for maxillary expansion in a study by Fernanda Angelieri speculated that at stages A and B, a conventional RME approach would have less resistant forces and probably show more skeletal effects than at stage C. In stage C, there were many initial ossification areas along the mid- palatal suture and the amount of skeletal effects observed might vary from case to case. In stage D and E, ossification continues to fuse palatal and maxillary parts causing more resistance to RME. Present study findings also support the same.
The more recent CBCT with low radiation is the choice for the diagnosis of the overall antero-posterior characteristics of the mid- palatal suture, without overlapping of other anatomic structures. Since we had large number of existing CT records in our institution instead of CBCT, we have utilized CT images for analysis.
| Conclusion and Recommendation|| |
The present study results showed that the CBCT-based prediction of stages of mid- palatal suture maturation related to the age and gender by Fernanda Angelieri is valid among the Indian population.
The present study results show that Indian children, up to age of 10 years, were distributed in stage A and B. After 11 years, up to 14 years especially, girls showed varied distribution among stages distributed equally among stage B, C, and D. After 15 years, girls were distributed maximum in stage D and E, whereas boys remained distributed variedly in stage B, C, and D. These findings suggests, for treatment plan of maxillary expansion among children above 10 years, it is better to have a diagnostic CBCT image analysis of mid-palate suture for predicable prognosis.
The authors would like to thank JSS Medical College and Hospital for their cooperation during the study.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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H P Chanchala
Department of Pedodontics, JSS Dental College and Hospital, JSS University, Mysore, Karnataka
Source of Support: None, Conflict of Interest: None
[Figure 1], [Figure 2]
[Table 1], [Table 2], [Table 3], [Table 4], [Table 5], [Table 6]