“There is but one best way” was the credo of Edward H. Angle and, like the US constitution, its authenticity is ongoing because of its ability to change. Fundamentalists might say that the “best way” means there is but a single static “best way” to practice orthodontics and argue for a return to Angle's original thinking. Others will say that the “best way” means a continuous quest for the best way to practice orthodontics and a broader philosophical guide encouraging objective thinking and growth.

The Angle Orthodontist began in 1930 as a living tribute to Edward H. Angle. The

Abstract

This study assesses the nickel content of as-received and retrieved stainless steel and NiTi archwires alloys. New and used brand-matched, composition-matched, and cross section–matched archwires were subjected to scanning electron microscopy and energy-dispersive electron probe microanalysis. Elemental analysis was performed on three randomly selected areas, and the nickel content, expressed as ratios of Ni/Ti (in NiTi wires) or Ni/Fe (in stainless steel), was statistically analyzed with a t-test (α = .05). No changes were detected with respect to Ni content ratios between as-received and retrieved NiTi or stainless steel wires, suggesting an absence of nickel release. Wear and delamination phenomena on the wire surface and the formation of galvanic couple between the stainless steel wires and bracket brazing materials intraorally may modify the corrosion susceptibility of the wire alloys in clinical conditions.

Abstract

The aim of this study was to explore the effects of differences in landmark identification on the values of cephalometric measurements on digitized cephalograms in comparison with those obtained from original radiographs. Ten cephalometric radiographs were randomly selected from orthodontic patients' records. Seven orthodontic residents identified 19 cephalometric landmarks on the original radiographs and digitized images. Twenty-seven cephalometric measurements were computed with a customized computer-aided program. To assess the concordance between cephalometric measurements derived from landmarks identified on the original radiographs and those from digitized counterparts, the values of 27 cephalometric measurements were compared to quantify the absolute value of measurement difference and the interobserver errors between these two methods. We found that the differences of all cephalometric measurements between original radiographs and their digitized counterparts were statistically significant. The differences in 21 of the 27 cephalometric items were less than two units of measurement (mm or degree), which is generally within one standard deviation of norm values in conventional cephalometric analysis. Moreover, statistically significant differences of interobserver errors between the two methods were noted only for seven of the 27 cephalometric items. In conclusion, the measurement differences between the original cephalograms and the digitized images are statistically significant but clinically acceptable. The interobserver errors for cephalometric measurements on our digitized cephalometric images are generally comparable with those on the original radiographs. The results of our study substantiated the benefits of digital cephalometry in terms of the reliability of cephalometric analysis.

Abstract

It is perceived that fuller lips are more attractive, and hence lip augmentation has become common in esthetic plastic surgery. Numerous materials have been used, including collagen, autologous adipocytes, and more recently Restylane®; however, little data exist on what comprises esthetically beautiful lips. Photographs of 28 models from fashion magazines were scanned to obtain digital images. These were selected strictly, using only exactly anterior-facing pictures. Using image analysis software, a range of defined lengths, angles, the lip area, and perimeter were measured. Lengths were expressed as a ratio of the intercanthal distance. A group of 14 nonmodel hospital employees were used as controls, with images obtained using a digital camera, and the same measurements were calculated. Results were compared for the two groups, and statistical analysis was performed using the Student's t-test. Overall lip width was not significantly different between the two groups (models, 15.7 units; nonmodels, 15.9 units). Both upper- and lower-lip height was significantly greater in models than in nonmodels (models, 2.1 and 3.6 units; nonmodels, 1.6 and 2.7 units, respectively), as was the upper-lip height laterally at the point of the angle of cupid's bow. Correspondingly, the angles of both upper and lower lips were also greater in models (models, 30.0° and 47.3°; nonmodels, 23.2° and 37.6°, respectively). We have assumed the model group to have esthetically beautiful lips. Our quantitative measurements have confirmed that this population has fuller lips compared with nonmodel controls, as determined by the lip height and angles.

Effects of printing layer thickness and build orientation on the mechanical properties and color stability of 3D-printed clear aligners

Chengzan Wu,

Utkarsh Mangal,

Na Bai,

Hoon Kim,

Geelsu Hwang,

Jung-Yul Cha,

Kee-Joon Lee,

Jae-Sung Kwon, and

Sung-Hwan Choi