A study of the panoramic radiographic images of the buccolingual dilaceration / 대한구강악안면방사선학회지

PURPOSE: We want to identify the appearance of the buccolingual root dilaceration teeth in the panoramic views and specify the characteristics of these teeth. MATERIALS AND METHODS: One thousand-six patients were examined on the basis of both panoramic and CT image criteria. We diagnosed and excluded certain teeth from the samples; both prosthodontic or pathologic lesion appearing teeth and mesiodistally dilacerated ones. We meticulously discerned buccolingually dilacerated teeth in the CT images and total 48 samples were selected. The degree of severity in dilaceration was standardized by 2 types of criteria. The samples were differentiated into 3 groups and again categorized into six types showing from the panoramic views: irregular view on the root apex area, clear blunt on the root tip, stepping on root tip, double lamina dura or double tip, arrow-target shaped root, bull's eye, normal view. RESULTS: The types of teeth selected from total 48 buccolingual root dilaceration samples were mandibular first and second molar, premolars, canines, and lateral incisors. The direction of dilaceration was an even percentage to each buccal and lingual side for most selected teeth, however, that of both canines and lateral incisors were directed in almost a buccal side. In the panoramic views, the root types of the buccolingually dilacerated teeth were irregular view on the root apex area, clear blunt on the root tip, stepping on root tip and normal types were almost always normal view. The more severity in dilareated degree, the more chances of observation in the panoramic views were clear blunt on the root tip and stepping on root tip. CONCLUSION: As observed in the shape of stepping on root tip or double lamina dura in the panoramic views, there can be much more probability to diagnose as a buccolingually dilacerated root.

Diagnostic imaging analysis of the impacted mesiodens / 대한구강악안면방사선학회지

PURPOSE: The research was performed to predict the three dimensional relationship between the impacted mesiodens and the maxillary central incisors and the proximity with the anatomic structures by comparing their panoramic images with the CT images. MATERIALS AND METHODS: Among the patients visiting Seoul National University Dental Hospital from April 2003 to July 2007, those with mesiodens were selected (154 mesiodens of 120 patients). The numbers, shapes, orientation and positional relationship of mesiodens with maxillary central incisors were investigated in the panoramic images. The proximity with the anatomical structures and complications were investigated in the CT images as well. RESULTS: The sex ratio (M : F) was 2.28 : 1 and the mean number of mesiodens per one patient was 1.28. Conical shape was 84.4% and inverted orientation was 51.9%. There were more cases of anatomical structures encroachment, especially on the nasal floor and nasopalatine duct, when the mesiodens was not superimposed with the central incisor. There were, however, many cases of the nasopalatine duct encroachment when the mesiodens was superimpoised with the apical 1/3 of central incisor (52.6%). Delayed eruption (55.6%), crown rotation (66.7%) and crown resorption (100%) were observed when the mesiodens was superimposed with the crown of the central incisor. CONCLUSION: It is possible to predict three dimensional relationship between the impacted mesiodens and the maxillary central incisors in the panoramic images, but more details should be confirmed by the CT images when necessary.

The relationship between the TMJ internal derangement state including rotational displacement and perforation and the clinical characteristics / 대한구강악안면방사선학회지

This study was designed to reveal the correlationship between the internal derangement state of TMJ and clinical characteristics including pain and mandibular dusfuntion. One hundred and twenty five subjects with TMJ signs and symptoms were chosen for two years. The level of pain and mandibular dysfuntion were evaluated by Visual Analog Scale(VAS) and Craniomandibular Index(CMI). The diagnostic categories of TMJ internal derangement were determined by arthrography and they included normal disc position, anterior disc displacement with reduction(ADDR), rotational disc displacement with reduction(RDDR), andterior disc displacement without reduction(ADDNR), and rotational disc displacement without reduction(RDDNR). Also disc perforation was used as a criteria to divide the diagnostic subgroups. The obtained results were as follows ; 1. The patient distribution of each group was 5 in normal disc position(4%), 40 in ADDR(32%), 30 in RDDR(24%), 34 in ADDNR(27%), and 16 in RDDNR(13%). 2. Perforation was observed in 8% of ADDR, 10% of RDDR, 32% of ADDNR, and 19% of RDDNR. 3. CMI of perforation group was higher than that of reduction or normal group(P0.05).