ABSTRACT
<p><b>OBJECTIVE</b>We measured and analyzed the angle between the longitudinal axis of incisor crown and tooth to provide a reference for orthodontists for selecting orthodontic methods and evaluating treatment results.</p><p><b>METHODS</b>A total of 120 participants were included according to the criteria of Andrews' six keys, and cephalometric radiograph under the instructions of modified natural head position acquirement method was performed. The angles of maxillary incisor crown longitudinal axis, tooth longitudinal axis, occlusion plane (OP), and true vertical (TV) plane were measured, as well as mandibular incisors.</p><p><b>RESULTS</b>As for maxillary incisors, the angle between crown longitudinal axis and TV plane, OP, and tooth longitudinal axis were 11.72°±4.71°, 73.29°±5.69°, and 20.04°±3.71°, respectively. For mandibular incisors, the angle between crown longitudinal axis and TV plane, OP, and tooth longitudinal axis were 16.03°±5.40°, 81.76°±4.81°, and 14.82°±4.01°, respectively. For the maxillary incisor, the angles between crown longitudinal axis and tooth longitudinal axis were mainly within 15° to 25°, whereas those for mandibular incisors were within 10° to 20°.</p><p><b>CONCLUSIONS</b>The longitudinal axis inclinations of the maxillary and mandibular incisor crown and of the incisor tooth need to be considered when cephalometric radiographs are used for treatment planning or for evaluating the treatment result.</p>
Subject(s)
Humans , Cephalometry , Dental Occlusion , Incisor , Mandible , Maxilla , Tooth CrownABSTRACT
<p><b>OBJECTIVE</b>To evaluate the accuracy of positron emission tomography (PET)/computed tomography (CT) for detecting cervical nodule metastases of oral and maxillofacial cancer.</p><p><b>METHODS</b>Diagnostic test accuracy studies assessing the accuracy of PET/CT in diagnosis of cervical metastases of oral and maxillofacial cancer were retrieved from the databases of CBM, Medline (OVID) and EMBASE (searched on Dec. 13th, 2010) and manual searching of 19 dental journals in Chinese. Two researchers were employed in the articles investigation independently and evaluated the quality with quality assessment of diagnostic accuracy studies (QUADAS). Meta-analysis was done using MetaDisc 1.4.</p><p><b>RESULTS</b>Nine studies met the inclusion criteria and demonstrated high methodological quality. The results of Meta-analysis showed that, when nodal level was used as unit, PET/CT had good diagnostic value in detecting the cervical nodule metastases of oral and maxillofacial cancer. Under such a condition, the pooled sensitivity was 0.84, pooled specificity 0.93, pooled diagnostic odds ratio 47.89 and area under the curve 0.973 8.</p><p><b>CONCLUSION</b>The accuracy of PET/CT for detecting cervical nodule metastases of oral and maxillofacial cancer is relatively high and it could be used as a good diagnostic tool. And special attention should be payed to its diagnostic expense and safety when considering PET/CT.</p>