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Objective: The objective of this study was to investigate the clinical and radiographic features of osteoarthrosis (OA) of the temporomandibular joints (TMJOA) in human adolescents and young adults., Study Design: Patients (n = 4883) with temporomandibular disorders (age, 11 to 30 years) underwent clinical and radiographic examinations. The radiographic findings were classified as erosive bony changes, proliferative changes mainly, including flattening with uneven sclerosis, and osteophytes of the condyle, and bilaterally short condylar processes. In addition, we interpreted the reassessment radiographs of 156 of the patients., Results: Seven hundred eleven patients had radiographic signs of OA. The frequency of OA was higher in women (563/3360, 16.8%) than in men (148/1523, 9.7%). Most patients (541/711, 76.1%) with signs of OA showed proliferative changes of OA. Moreover, 56.4% of patients with TMJOA (88/156) remained stable., Conclusions: These results suggest that although OA is an age-related disease, aging is not the crucial factor in the pathogenesis of OA., (Copyright © 2011 Mosby, Inc. All rights reserved.)

Objective: The aim of this study was to investigate with cone-beam computed tomography (CBCT) the locations of impacted maxillary canines and resorption of neighboring incisors., Study Design: Two hundred ten impacted maxillary canines were analyzed using CBCT images. The locations of the impacted canines were assessed and angular and linear measurements were taken using NewTom proprietary software. In addition, root resorption of neighboring incisors was investigated., Results: Among these impactions, 45.2% were impacted buccal-labially, 40.5% were impacted palatally, and 14.3% in the midalveolus. The locations varied: mesial-labial impaction (n = 67), mesial-palatal impaction (n = 74), in situ impaction (n = 31), distal impaction (n = 12), horizontal impaction (n = 18), and inverted impaction (n = 8). Quantitive measurements further depicted these variations. Root resorption was present in 27.2% of lateral and 23.4% of central incisors, and 94.3% of these resorptions occurred where the impacted canines were in close contact with the incisors., Conclusion: The location of impacted maxillary canines varies greatly in 3 planes, and the resorption of neighboring permanent incisors is common.

Purpose: The purpose of this article is to introduce the use of cone-beam computed tomography (CBCT) for evaluation of supernumerary teeth., Methods: The study group comprised 487 patients with a total of 626 supernumerary teeth who were examined by CBCT. Patient characteristics were recorded, and the number, location, shape, and 3-dimensional position of the supernumeraries were analyzed. The ability of CBCT to visualize dental and skeletal structures relative to supernumerary teeth was also evaluated., Results: Males were affected more than females in a ratio of 2.64:1. Seventy-two percent of the patients had 1 supernumerary tooth, 27.3% had 2, and 0.6% had 3 supernumeraries. Supernumerary teeth were most frequently located in the anterior maxilla (92%), and their sagittal location relative to the neighboring teeth could be used for classification purposes. Supernumeraries were most commonly conical in shape (83.5%). CBCT yielded accurate 3-dimensional pictures of the dental and bony structures. The sagittal positions of the 578 supernumerary teeth in the anterior maxilla were divided into 6 types, of which types I and III were most commonly associated with local malocclusions. Moreover, 43.4% of the premaxillary supernumeraries were inverted and 21.1% were transversely oriented., Conclusions: CBCT imaging yields accurate 3-dimensional pictures of local dental and bony structures, which is helpful for pretreatment evaluation of supernumerary teeth.