Roopa @ Kunthavai, C (2015) Assessment of degree of treatment difficulty of maxillary canine impaction using KPG index and to analyse lateral incisor root resorption by 3D CBCT: A retrospective study. Masters thesis, Tamilnadu Government Dental College and Hospital, Chennai.
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Abstract
AIM OF THE STUDY: The aim of the study is to assess the degree of difficulty for the treatment of impacted canines using KPG index and to analyse the lateral incisor root resorption using CBCT. OBJECTIVES: 1. To determine the position of maxillary canine in 3D and analyse type of impaction. 2. To assess the degree of difficulty for the treatment of impacted maxillary canine using KPG index. 3. To find the reliability in assessing the KPG index by inter and intrarater agreement. 4. To find the agreement between 2D and 3D methods in predicting treatment difficulty. 5. To relate the severity of Lateral incisor root resorption to score of KPG index. MATERIALS AND METHODS: This was a retrospective study in which records of Cone beam images were obtained from the Department of Oral Medicine and Radiology, Tamil Nadu Government Dental College and Hospital, Chennai-600003.CBCT images of 28 patients taken from January 2013 to December 2013 with maxillary canine impactions were assessed out of which 15 female and 13 male in the age group of 13-28years(mean age=18 years) . A total of 42 canines were assessed with KPG index. DICOM (Digital Imaging and Communications in Medicine) files were obtained from KODAK 9500 cone beam 3D Extraoral imaging system with a reconstruction volume of 50x37mm and a reconstructed matrix voxel of 76.5x76.5x76.5μm. The equipment had CMOS sensor technology. Exposure parameters for the patients varied from 90 kV, 10 mA with a scan time of 10.8 seconds. The impacted teeth were assessed by the 3 D volumetric image and 1 mm tomographic sections in sagittal, axial and coronal planes. The field of view was 9 x 15cm (from the bottom of the chin to the top of the jaw). Cross sectional CBCT images were evaluated for labial, mid alveolus and palatal position of the impaced canine, type of impaction, root resorption of the permanent incisors. All the images were visualized by Carestream 3D software(CS3D) on a standard15.6 inch screen with 1366 x 768 pixel resolution. SUMMARY AND CONCLUSION: The present study was done at Department of Orthodontics and Dentofacial orthopedics, Tamil Nadu Government Dental College and Hospital. Patients CBCT records were retrieved from the Department of Oral Medicine and Radiology taken from January to December 2013. Total 28 patients with 42 impacted maxillary canine, age group ranging from 13 to 28 years (mean age = 18 years) of either gender were included in the study. The impacted teeth were assessed by the 3 D volumetric image and 1 mm tomographic sections in sagittal, axial and coronal planes. Cross sectional CBCT images were evaluated for labial, mid alveolus and palatal position of the impaced canine, type of impaction, root resorption of the permanent incisors. All the images were visualized by Carestream 3D software(CS3D). The aim of the study was to assess the degree of difficulty for the treatment of impacted canines using KPG index and to analyse the lateral incisor root resorption using CBCT. This is, to determine the position of maxillary canine in 3D and analyse type of impaction, to assess the degree of difficulty for the treatment of impacted maxillary canine using KPG index, to find the reliability in assessing the KPG index by inter and intrarater agreement, to find the agreement between 2D and 3D methods in predicting treatment difficulty and to relate the severity of Lateral incisor root resorption to the score of KPG index. Digital Panaromic radiograph was created from three dimensional scans. Firstly, the localisation of the impacted maxillary canines was done 3-dimensionally i.e., the location and distribution of impacted canines were assessed and the orientation of the impacted canines were recorded as 6 types given by Liu et al51 namely mesio-palatal, mesio-labial, mesio-distally insitu, distal, horizontal and inverted. In this study, out of 42 total impactions,31% were M-P-I,26% were M-L-I,26% were In situ,7% were Distal and 10% were Horizontal impactions. Inverted impactions were not reported in this study. The novel KPG index was used to assess the treatment difficulty of maxillary impacted canines in this study. Out of 42 canines assessed,30 were with moderate score,10 were with difficult score,1 with extremely difficult and 1 with easy score. An easy impaction would require a short time of treatment and may need basic orthodontic guidance. A moderate impaction requires longer treatment times, and an impacted canine scored as difficult would require even lengthier treatment, involving more advanced orthodontic techniques. An impaction that is classified as extreme difficulty for the orthodontist could require the intervention of an oral surgeon before the canine can be brought into position, or the impacted tooth may simply need to be extracted. On evaluating the level of agreement between observers in assessment of canine impactions using KPG index, we found almost perfect agreement in this study. Kappa statistics were done to analyse it. It showed that this index is highly reliable and further prospective studies are needed to confirm its validity in estimating accurate treatment time with differing mechanics. In doing so, this novel 3-D KPG index will become increasingly valuable to orthodontists. Reliability of this KPG index with 2D measures of difficulty assessment of canine impaction was also carried out in our study using chi-square tests with Yates correction. It was found that statistically significant association was present between KPG index and 2D methods and the results indicate that 3D radiological techniques, could allow us to better understand how the position of an impacted canines relates to treatment time. The final aim of our study was to relate the severity of lateral incisor root resorption to the score of KPG index. In recent years, CBCT has been found to be a valuable tool in the detection of root resorption associated with impacted canines12. In this study, the occurrence and the extent of root resorption in CBCT based on the grading system given by Ericson and Kurol48 was evaluated. Contact relationship of impacted canines with maxillary central and lateral incisors was analysed.88% of lateral incisor and 60% of central incisors had contact with maxillary impacted canines. 3-dimensional observation of root resorption was graded as no resorption, slight, moderate and severe. Out of 41 lateral incisors assessed, 13 had 'no' resorption,17 had 'slight',10 had 'moderate' and 1 had 'severe' resorption. Amongst 42 central incisors, 32 had no resorption,6 had 'slight', 2 had 'moderate' and 2 had 'severe' resorption. This showed lateral incisors were more affected than central incisors by root resorption and most of the resorptions occured where the canine was in close contact with the lateral incisors. Finally, we compared the severity of these lateral incisor root resorption and the score of KPG index by conducting one way ANOVA analysis. This showed statistically significant result and, as the mean KPG increases LIRR increased in their severity grade. By this study, we validated the difficulty score of the novel 3-D KPG index with increasing grade of lateral incisor root resorption. This may help in prediction of the lateral incisor root resorption from the difficulty score of KPG index.
| Item Type: | Thesis (Masters) |
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| Uncontrolled Keywords: | maxillary canine impaction ; KPG index and ; lateral incisor root resorption ; 3D CBCT ; retrospective study. |
| Subjects: | DENTAL > Orthodontics and Dentofacial Orthopedics |
| Depositing User: | Subramani R |
| Date Deposited: | 14 Oct 2018 19:29 |
| Last Modified: | 14 Oct 2018 19:29 |
| URI: | http://repository-tnmgrmu.ac.in/id/eprint/9892 |
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