“…1). Two images were automatically registered by voxelization, skin segmentation, and the Chamfer distance transformation using the Morpheus 3D software [11]. Fig.…”
Background
To evaluate the three-dimensional (3D) changes after mandibular setback surgery (MSS) in skeletal Class III malocclusion using cone-beam computed tomography (CBCT) and a structured light-based scanner.
Methods
Twenty-eight adult Korean patients with skeletal Class III malocclusion treated by MSS were evaluated. CBCT and facial scan images were recorded one week before and six months after surgery. To use an identical 3D coordinate system, superimposition was performed, and nine skeletal and 18 soft tissue landmarks were identified. Changes in the landmarks and correlation coefficients and ratios between hard and soft tissue changes were evaluated. Paired
t
test and Pearson’s correlation test were performed.
Results
After MSS, the amount of transverse correction was 2.45 mm; mandibular setback, 5.80 mm; and vertical reduction, 1.64 mm at the menton, on average. In the transverse axis, there were significant changes and correlations in the lips and chin and an increasing gradient of ratios from the lower lip to the chin. In the anteroposterior axis, the lower lip and chin moved backward significantly and showed notable correlation with hard tissue movement. In the vertical axis, significant upward movement was observed in the landmarks related to the chin, but only lower facial height was significantly decreased.
Conclusions
Soft tissue changes according to hard tissue movement after MSS exhibited a distinct pattern of an increasing gradient from the lips to the chin in a transverse aspect.
“…1). Two images were automatically registered by voxelization, skin segmentation, and the Chamfer distance transformation using the Morpheus 3D software [11]. Fig.…”
Background
To evaluate the three-dimensional (3D) changes after mandibular setback surgery (MSS) in skeletal Class III malocclusion using cone-beam computed tomography (CBCT) and a structured light-based scanner.
Methods
Twenty-eight adult Korean patients with skeletal Class III malocclusion treated by MSS were evaluated. CBCT and facial scan images were recorded one week before and six months after surgery. To use an identical 3D coordinate system, superimposition was performed, and nine skeletal and 18 soft tissue landmarks were identified. Changes in the landmarks and correlation coefficients and ratios between hard and soft tissue changes were evaluated. Paired
t
test and Pearson’s correlation test were performed.
Results
After MSS, the amount of transverse correction was 2.45 mm; mandibular setback, 5.80 mm; and vertical reduction, 1.64 mm at the menton, on average. In the transverse axis, there were significant changes and correlations in the lips and chin and an increasing gradient of ratios from the lower lip to the chin. In the anteroposterior axis, the lower lip and chin moved backward significantly and showed notable correlation with hard tissue movement. In the vertical axis, significant upward movement was observed in the landmarks related to the chin, but only lower facial height was significantly decreased.
Conclusions
Soft tissue changes according to hard tissue movement after MSS exhibited a distinct pattern of an increasing gradient from the lips to the chin in a transverse aspect.
“…Nahm et al [ 21 ] also similarly found the registration relationship between CBCT and facial surfaces to be very close and concluded that merging CBCT and facial scans can produce a much truthful image of the patient to give the orthodontist enhanced diagnostic information and lessen errors in diagnosis. These findings agree with the present study, since it was found that other than some of the few distances mentioned above, many other ratios have excellent soft tissue to CBCT ratio percentages, such as the width between outer eye corners (−0.74%), left (−2.94%) and right (−3.99%) corners of the mouth to EAM, and the nasion to gnathion (−4.38%) measurement.…”
Objective Compare measurements of skeletal and dental areas on the CBCT to the corresponding soft-tissue measures taken from a 3D Facial Scanner. Methods 30 patients with CBCT and 3D Facial scanner photos were selected from the orthodontic program database. 30 different distance measurements were obtained from CBCT and facial scan. OrthoInsight software was used to obtain the measurements from the facial scan images, and AVIZO software was used for corresponding CBCT landmarks. The Euclidean distance formula was used to determine the distances for the corresponding x, y, and z coordinates of the CBCT. Reliability for CBCT and Facial Scanner was completed by calculating 30 distances for 10 patients, 3 times. Once reliability was determined, all 30 distances were calculated once for CBCT and facial scanner on each patient and descriptive statistics and paired t-test were applied. Results All distances measured presented excellent reliability, the lowest one being the left eye width for the facial scanner (ICC 0.847). The landmark with the highest mean error on the CBCT was 2.0 ± 1.6 mm on the z-axis for the spinal level landmark. The Facial Scanner's largest mean measurement error was 1.5 ± 0.9 mm for the distance of the left corner of the mouth to gonion. All data except width between outer eye corners were statistically significant (p < 0.05). The average differences between facial scan and CBCT measurements ranged between 0.77 mm (left canine to cheekbone) to 26.94 mm (left subnasale to gonion) and are thus comparable. All measurements show a reasonable standard deviation between 2.57 mm (left eye width) to 9.91 mm (left gnathion to EAM). Conclusion Distances obtained from CBCT and facial scan present mild differences giving the perspective of a relationship between them. Understanding this difference and relationship can make it plausible to expect certain underlying skeletal distances under soft-tissue structures.
“…However, 3-dimensional facial surface scans have been co-registered with cone-beam computed tomography data, 43 and the method could be used to identify bone position in relation to tissue damage. Facial bone distances have been determined from correlations of magnetic resonance imaging data and frontal color photographs, suggesting that photographs could be used to judge bone location.…”
BACKGROUND: Pressure ulcers (stages III and IV) are serious safety events (ie, never events).Healthcare institutions are no longer reimbursed for costs to care for affected patients. Medical devices are the leading cause of pediatric pressure ulcers. Face masks for noninvasive ventilation were associated with a high percentage of pressure ulcers at our institution. METHODS: A prospective cohort study investigated factors contributing to pressure ulcer development in 50 subjects using face masks for noninvasive ventilation. Color imaging, 3-dimensional surface imaging, and skin hydration measurements were used to identify early skin compromise and evaluate 3 interventions to reduce trauma: (1) a silicone foam dressing, (2) a water/polyethylene oxide hydrogel dressing, and (3) a flexible cloth mask. A novel mask fit technique was used to examine the impact of fit on the potential for skin compromise. RESULTS: Fifty subjects age 10.4 ؎ 9.1 y participated with color images for 22, hydration for 34, and mask fit analysis for 16. Of these, 69% had diagnoses associated with craniofacial anomalies. Stage I pressure ulcers were the most common injury. Skin hydration difference was 317 ؎ 29 for sites with erythema versus 75 ؎ 28 for sites without erythema (P < .05) and smallest for the cloth mask (P < .05). Fit distance metrics differed for the nasal, oronasal, and face shield interfaces, with threshold distances being higher for the oronasal mask than the others (P < .05). Areas of high contact were associated with skin erythema and pressure ulcers. CONCLUSIONS: This fit method is currently being utilized to select best-fit masks from available options, to identify the potential areas of increased tissue pressure, and to prevent skin injuries and their complications. Improvement of mask fit is an important priority for improving respiratory outcomes. Strategies to maintain normal skin hydration are important for protecting tissue integrity.
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