Tooth wear patterns in subjects with class II division 1 and class II division 2 malocclusion.

INTRODUCTION: There is an increasing trend of malocclusion among children, so it is necessary to identify the cause of the tooth wear so that the orthodontist can treat the patient accordingly. It is necessary to determine the wear patterns of different malocclusions. Therefore, the aim of our study was to compare the patterns of tooth wear among two categories of Angle's class II malocclusions, i.e. class II division 1 and class II division 2. MATERIAL AND METHODS: The sample consisted of 100 pretreatment orthodontic patients in the age group of 15-25 years with Angle's class II malocclusion and were divided into following two groups: (a) Group 1: 50 subjects with full cusp Angle's class II division 1 malocclusion. (b) Group 2: 50 subjects with full cusp Angle's class II division 2 malocclusion. Clinical examination of the patients for tooth wear was done supplemented with dental casts, intraoral photographs and intraoral radiographs. Then each group was assessed for severity of tooth wear according to modified tooth wear index (TWI) given by de Carvalo Sales-Peres et al. Scores were subjected to statistical analysis and the pattern of tooth wear among the two groups of class II malocclusion was compared. A correlation between the gender of the patient and the tooth wear was also determined. The level of statistical significance (p-value) was less than 0.05. RESULTS: The class II division 1 subjects showed statistically greater wear on the occlusal surfaces of the maxillary canines, first, second premolar and first molar, and the occlusal surfaces of the mandibular first molars. The class II division 2 subjects showed statistically greater tooth wear on the labial surfaces of the mandibular central and lateral incisors, the incisal surface of maxillary and mandibular incisors, the palatal surfaces of the maxillary second premolars, first and second molars. In class II division 1 subjects, the tooth wear was significant on the buccal surface of maxillary canines, occlusal surface of mandibular first premolars and second molars in males. In class II division 2 subjects, the tooth wear was significant on the buccal surface of mandibular canines, palatal surface of maxillary central incisors in females and palatal surface of maxillary first premolars in males. CONCLUSIONS: The results of this study suggested that the two categories of Angle's class II malocclusion have different tooth-wear patterns. The wear patterns were different in both the sexes. Men showed higher occlusal wear scores than did women. The findings also suggest that tooth wear in relation to malocclusion is physiologic and is due to dissimilar interocclusal arrangement.

Changes in Cranial Base Morphology in Class I and Class II Division 1 Malocclusions.

INTRODUCTION: The cranial base plays a key role in craniofacial growth; it helps to integrate spatially and functionally different patterns of growth in various adjoining regions of the skull such as components of the brain, the nasal and oral cavity and the pharynx. The aim of this study was to evaluate the difference in cranial base flexure between skeletal and dental Class I and Class II division 1. MATERIALS & METHODS: Lateral cephalometric radiograph, of Class I and Class II with an average growth pattern were analyzed and compared. A total of 103 patients having class I (n=52) and class II (n=51) malocclusion, were taken from Department of Orthodontics, Rajasthan Dental College & Hospital, Jaipur. Cranial base angle (N-S-Ar) and ANB were measured on pre treatment lateral cephalograms. RESULTS: In this study cranial base angle did not show statistically significant difference between the two groups studied. CONCLUSION: In the assessment of orthodontic problems involving anteroposterior malrelationships of the jaws, the problem is usually the result of size, form and position of the jaw. The present study failed to find any differences in cranial base angle between sagittal malocclusions. How to cite this article: Agarwal A, Pandey H, Bajaj K, Pandey L. Changes in Cranial Base Morphology in Class I and Class II Division 1 Malocclusion. J Int Oral Health 2013; 5(1):39-42.

Comparison of the Reliability of Anatomic Landmarks based on PA Cephalometric Radiographs and 3D CT Scans in Patients with Facial Asymmetry.

INTRODUCTION: Conventional cephalometry is an inexpensive and well-established method for evaluating patients with dentofacial deformities. However, patients with major deformities and in particular asymmetric cases are difficult to evaluate by conventional cephalometry. Reliable and accurate evaluation in the orbital and midfacial region in craniofacial syndrome patients is difficult due to inherent geometric magnification, distortion and the superpositioning of the craniofacial structures on cephalograms. Both two- and three-dimensional computed tomography (CT) have been proposed to alleviate some of these difficulties. AIMS AND OBJECTIVES: The aim of our study is to compare the reliability of anatomic cephalometric points obtained from the two modalities: Conventional posteroanterior cephalograms and 3D CT of patients with facial asymmetry, by comparison of intra- and interobserver variation of points recorded from frontal X-ray to those recorded from 3D CT. MATERIALS AND METHODS: The sample included nine patients (5 males and 4 females) with an age range of 14 to 21 years and a mean age of 17.11 years, whose treatment plan called for correction of facial asymmetry. All CT scans were measured twice by two investigators with 2 weeks separation for determination of intraobserver and interobserver variability. Similarly, all measurement points on the frontal cephalograms were traced twice with 2 weeks separation. The tracings were superimposed and the average distance between replicate points readings were used as a measure of intra- and interobserver reliability. Intra-and interobserver variations are calculated for each method and the data were imported directly into the statistical program, SPSS 10.0.1 for windows. RESULTS: Intraobserver variations of points defined on 3D CT were small compared with frontal cephalograms. The intraobserver variations ranged from 0 (A1, B1) to 0.6 mm with the variations less than 0.5 mm for most of the points. Interobserver variations of points between first and second tracings defined on PA Ceph and 3D CT were less than 1.5 mm for all the points. A direct comparison of frontal cephalometry and 3D CT using intraobserver variation for the first observer showed that 3D CT was more reliable than frontal cephalometry for 11 points. Direct comparison of frontal cephalometry and 3D CT for the second observer showed a similar tendency with 14 points significantly more reliable for 3D CT. Comparison of frontal cephalometry and 3D CT using interobserver variation for the tracings showed that 3D CT was more reliable than frontal cephalometry. SUMMARY AND CONCLUSION: The study has shown that 3D CT is consistently more accurate and reliable than conventional frontal cephalometry. Unfortunately, the cost of a computerized tomography examination is considerable; this means that, at this stage, its use by surgeons and orthodontists is a last resort.