![]() Using these values, the vertical dimension and the antero-posterior horizontal distance (horizontal distance) of the new bite block was determined. The conventional standard bite block for anterior dentulous patients. The new bite block for anterior edentulous patients. Also, the extent of anterior alveolar bone resorption was 5.90 mm in non-denture wearers and 6.69 mm in denture wearers in the maxillary central incisor area, and 7.07 mm in non-denture wearers and 13.03 mm in denture wearers in the mandibular central incisor area. 15 Thus, the angle between the maxillary central incisor and vertical plane was 26.71°, and the angle between the mandibular central incisor and vertical plane was 19.65°. 14 The mean angle between the occlusal plane and Frankfort horizontal plane was 6.79°. Furthermore, the mean facio-lingual inclination of the maxillary central incisors was 33.50°, and that of the mandibular central incisors was 26.44°. According to Volchansky and Cleaton-Jones, 13 the mean sizes of teeth were 10.0 mm among the maxillary central incisors and 8.4 mm among the mandibular central incisors in those aged 20 to 40 years. To compensate for those areas, statistical analysis of measured tooth lengths, facio-lingual inclinations, and resorbed anterior alveolar bone dimensions were investigated in the literature. The new bite block needed to compensate for the area of missing anterior teeth and resorbed alveolar bone. 3B) while undergoing panoramic radiography. 3A) was designed to position anterior edentulous patients in the same manner as anterior dentulous patients who could bite into the notches of a conventional standard bite block ( Fig. The dimensions of the missing and resorbed tissues were determined by referring to previous studies. The new bite block for edentulous patients involved modifications in the bite portion that could compensate for the missing anterior teeth and resorbed anterior alveolar bone tissue of anterior edentulous patients. 11 The chin-support device is more commonly used than the conventional bite block because the height of the bite block is 12 mm, which seems to provide an insufficient vertical dimension for the edentulous area.Ī new bite block for edentulous patients was designed to bring reproducibility when taking panoramic radiographs to a similar level as that of a bite block for dentulous patients. ![]() 1A and B, respectively), are widely available for positioning anterior edentulous patients during panoramic radiography. 10Ĭonventional bite blocks and chin-support devices, such as the ones included with the Orthopantomograph® OP100 (Imaging Instrumentarium, Tuusula, Finland) ( Figs. Accuracy and reproducibility of edentulous patients' panoramic radiographs are important for dental diagnosis and treatment planning because panoramic radiographs have been widely used in cases of the screening of cysts, foreign bodies, and neoplasms, 4, 5, 6 finding bone resorption and osteopenia of the jaws, 7, 8, 9 and installing implants. 3 showed that panoramic radiographs without positioning reproducibility were not reliable for diagnosis and evaluation of the edentulous mandible. 2 reported that 89% of panoramic radiographs of edentulous patients had at least one error, which included the following positions: chin too high, too far forward, tongue not raised, chin too low, head tilted, head turned, and too far back. 1 noted that most panoramic radiographs had at least one error. Without distinguishing between dentulous and edentulous images, Dhillon et al. ![]() Several studies have examined the difficulties of taking panoramic radiographs of edentulous patients. With edentulous patients, it is difficult to secure suitable positioning when taking panoramic radiographs and also it is hard to assess the positioning by means of inspecting anatomical structures such as the occlusal plane, antero-posterior position of the anterior teeth, and symmetry in their panoramic radiographs after taken.
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