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To quantify reliability of three-dimensional skeletal landmarks and a comprehensive set of dental landmarks in cone-beam computed tomography (CBCT) and to determine the shapes of envelope of error. Three judges located 31 skeletal landmarks and 60 dental landmarks on the pre- and posttreatment CBCT images of 22 patients. Landmark error was determined by calculating the distance of deviation of landmark locations around their average. Standard deviation and mean radial spherical error were calculated. Scatterplots were constructed to characterize envelope of error. The midline landmarks of the cranial base were highly reliable. Bilateral skeletal landmarks tended to have larger error than midline landmarks. Among the nonconventional landmarks, fronto-zygomatic suture, condyle, and mental foramen showed relatively high reliability. However, foramen spinosum and temporal fossa showed larger errors. Gonion was the least reliable landmark. Most dental landmarks were located more reliably than skeletal landmarks. The highest reliability was found at incisal edges. Mesiobuccal cusp of first molars also showed high reliability. There were differences in the size and shape of the distributions of errors of different landmarks. Most landmarks showed elongated envelopes. Bilateral structures tended to show greater errors than midline structures. Most dental landmarks were more reliable than skeletal landmarks. [ABSTRACT FROM AUTHOR]

The purpose of this study was to investigate the relationship between cephalometric nasal soft tissue and skeletal landmarks in adults. Lateral cephalograms from Japanese adults (30 men: mean age, 24.5?±?4.9?years; 30 women: mean age, 20.3?±?3.3?years; overall mean age, 22.4?±?2.4?years) were used in this study. Twenty-two skeletal points and three soft tissue nasal points were marked on each subject’s lateral cephalogram, and the coordinates of all the points were systematically digitised and transformed to a standardised plane. A forward stepwise regression analysis determined how combinations of the skeletal landmarks predict the location of the nasal soft tissue landmarks. Based on the result of our research, the location of the nasal soft tissue cephalometric landmarks in our adult subjects may be predicted based on skeletal landmarks, and different skeletal landmarks predicted the position of each soft tissue landmark in the adult males and females in this study. [ABSTRACT FROM PUBLISHER]

Abstract: The purpose of this study was to investigate the relationship between cephalometric nasal and skeletal landmarks in preschool children. Lateral cephalograms of 80 Japanese preschool children (40 boys, mean age 5.4±0.3 years; 40 girls, mean age 5.2±0.1 years; total mean age 5.3±0.3 years) were traced, and 22 skeletal and 3 soft-tissue nasal points were digitized. The coordinates from each subject were transformed to a standardized plane using a custom-made program written in Microsoft Visual C++®. In this standard plane, sella was the origin, Frankfort Horizontal (FH) plane was parallel to the X-axis, and all 25 points were rotated to match this reference plane. The three nasal landmarks used in this investigation were: (1) rhi’, the intersection point of a line parallel to the FH plane at rhinion and the facial line; (2) pronasale (Prn), the most anterior point on the nose; and (3) subnasale (Sn), the most posterior–superior point where the columella met the upper lip. An independent-groups t-test was used to test for sex differences of coordinates of the nasal landmarks and their related skeletal landmarks. Significance was set at p <0.05. A stepwise regression analysis determined how combinations of skeletal landmarks explained the location of the nasal landmarks. Only one skeletal coordinate (NX) and no nasal coordinates showed a significant difference between boys and girls. The coordinates of rhi contributed significantly to the location of rhi’ and Prn (except for the Y-coordinate of girls). Moreover A-point and ANS contributed to the location of Prn and Sn. For Sn, the X- and Y-coordinates of girls and the Y-coordinate of boys were related to lower incisor or dentoalveolar structure of the mandible. It appears that the nasal landmarks in preschool children can be predicted from selected skeletal landmarks, and there are no sex differences for the nasal landmarks in children. [Copyright &y& Elsevier]