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Speckle correlation technique to determine roughness in the dermatologic interval.
A non-invasive method is proposed to determine human skin roughness. The technique is based on measurement of the correlation between two field distributions scattered by a metallised triafol (cellulose acetate foil) replica of the epidermal area to be analysed. The two speckle patterns are produced from the same rough surface illuminated by two coherent plane waves (He-Ne laser) under two slightly different angles. The accuracy of the method is highlighted by measurements made on a set of standard samples with roughnesses previously determined by mechanical profilometry. Analysis of the results indicates a precision of around 10%, and an applicability within the interest range of very rough surfaces in excess of 4-5 microns.
Effects of erbium, chromium:YSGG laser irradiation on root surface: morphological and atomic analytical studies.
OBJECTIVE: The purpose of this study was to investigate the morphological and atomic changes on the root surface by stereoscopy, field emission-scanning electron microscopy (FE-SEM), and energy dispersive X-ray spectroscopy (SEM-EDX) after erbium, chromium:yttrium, scandium, gallium, garnet (Er,Cr:YSGG) laser irradiation in vitro. SUMMARY BACKGROUND DATA: There have been few reports on morphological and atomic analytical study on root surface by Er,Cr:YSGG laser irradiation. METHODS: Eighteen extracted human premolar and molar teeth were irradiated on root surfaces at a vertical position with water-air spray by an Er,Cr:YSGG laser at the parameter of 5.0 W and 20 Hz for 5 sec while moving. The samples were then morphologically observed by stereoscopy and FE-SEM and examined atomic-analytically by SEM-EDX. RESULTS: Craters having rough but clean surfaces and no melting or carbonization were observed in the samples. An atomic analytical examination showed that the calcium ratio to phosphorus showed no significant changes between the control and irradiated areas (p > 0.01). CONCLUSIONS: These results showed that the Er,Cr:YSGG laser has a good cutting effect on root surface and causes no burning or melting after laser irradiation.
Thermographical and morphological studies of Er,Cr:YSGG laser irradiation on root canal walls.
OBJECTIVE: This study was performed to investigate the temperature rises on root surfaces and morphological changes on root canal walls of extracted human teeth after irradiation by erbium, chromium: yttrium, scandium, gallium, garnet (Er, Cr:YSGG) laser and to evaluate the efficiency in removing smear layer and debris from the prepared root canal walls in vitro. BACKGROUND DATA: No report on Er, Cr:YSGG laser effects under various conditions and specific tips for endodontic treatments has been reported. METHODS: Sixty extracted human teeth with single and straight root were used in this study. The teeth were prepared at 1 mm short of the apical foramen by a conventional technique using K-files. Fifty-four specimens were irradiated by Er, Cr:YSGG laser at the output powers of 2 W, 3 W, and 5 W for 7 sec with three fiber tips (200, 320, and 400 microm diameters). Temperature changes were recorded thermographically. All teeth were examined by light microscopy or scanning electron microscopy (SEM). RESULTS: Thermographic study showed that the average temperature rises on root surfaces were less than 8 degrees C. Observation by light microscopy revealed the ablation at the apical stop, and that by SEM indicated that laser irradiation at 5 W using a fiber tip with 400 microm diameter was efficient for removing smear layer and debris without carbonization or melting. CONCLUSIONS: The results of this study suggested that the temperature rises during Er, Cr:YSGG laser irradiation at the parameters used in this study are minimal to cause the damage on periodontal and bone tissues. Moreover, it was suggested that it is efficient to remove smear layer and debris without causing any carbonization and melting.
Stereophotogrammetric evaluation of tracheal volumes in the rabbit.
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Stereophotogrammetric analysis of changes in body volume associated with the induction of anaesthesia.
Changes in the volume of the trunk were measured in seven supine patients, when anaesthesia was induced with thiopentone i.v. Stereo-photograms were taken before and after induction and measurements of volume calculated from contour plots of a reconstructed stereo image. The changes in volume of the visible part of the trunk were between -846 and +505 ml. No systematic change in total or lower trunk ("abdominal") volume was evident, but there was a significant negative linear relationship (r = -0.87) between upper trunk ("ribcage") volume change and obesity (expressed as actual weight/expected weight). Changes in volume were more evident in the upper parts of the supine subject, in both ribcage and abdomen (P less than 0.05).
Angular photogrammetric analysis of the soft tissue facial profile.
All medical specialties interested in improving facial appearance need to measure the face to quantify the desired facial changes. The purpose of this investigation was to obtain objective average measurements of the soft tissue facial profile to use them as a guide for aesthetic treatment goals. The analysis of the soft tissue facial profile from photographic records provides information on the morphology of the profile and its relationship with the underlying dentoskeletal tissues. In this investigation the soft tissue facial profile of a young adult European Caucasian population (212 individual, 50 males and 162 females, 18-20 years of age) was studied by means of standardized photographic records taken in the natural head position (NHP). Angular measurements were analysed digitally. Sexual dimorphism was found for several angles: nasofrontal (G-N-Prn: P < 0.01), vertical nasal (Cm-Sn/N-Prn: P < 0.01), nasal (N-Prn/TV: P < 0.01), nasal dorsum (N-Mn-Prn: P < 0.05), and mandibular contour (C-Me/G-Pg: P < 0.01). Wide individual variations in nasolabial and mentolabial angles were also observed.
The effect of congenital cardiac disease on facial growth in a monozygotic twin pair, studied by stereophotogrammetry.
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Stereoradiography of the anterior maxilla.
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Assessment of the accuracy of a three-dimensional imaging system for archiving dental study models.
OBJECTIVE: The use of stone and plaster study models is an integral part of any dental practice and is required for research. Storage of study models is problematic in terms of space and cost. Ayoub et al.(1) introduced a new technique based on the recent advances in stereophotogrammetry for archiving dental study models in a digital format. However, assessment of the accuracy of the generated three-dimensional (3D) models has not been carried out yet. It was the aim of this study to evaluate the accuracy of this technique. DESIGN: A comparative assessment between direct measurements of dental study models and measurements of computer generated 3D images of the same study models was performed. MATERIALS AND METHODS: Twenty-two dental study models stored at Glasgow Dental Hospital and School for the purposes of research were used in the study. The models were captured in three dimensions using a photostereometric technique and stored in digital format. MAIN OUTCOME MEASURES: Measurements were conducted directly on dental study models and on the computer generated 3D images using Euclidean Distance Matrix Analysis.(2) The difference between the two sets of measurements was statistically analysed using a two-sample t-test. RESULTS: The average difference between measurements of dental casts and 3D images was 0.27 mm. This difference was within the range of operator errors (0.10-0.48 mm) and was not statistically significant (P < 0.05). CONCLUSION: This study shows that it is possible to use 3D imaging to store dental study models for treatment monitoring and research with a satisfactory degree of accuracy.
Moiré topography in scoliosis. Correlations with vertebral lateral curvature as determined by radiography.
The backs of 42 subjects were examined using moiré topography; 22 of these subjects had scoliosis (range of lateral curvature, 6 degrees-95 degrees; mean, 31 degrees) and had recent radiographs of the spine. Two experienced observers, each an orthopedic surgeon, determined moiré angles and number of fringe deviations for each subject. Two radiologists assessed radiographic Cobb angles for each scoliotic subject. For major curves superior to T10 (n = 9), significant correlations were found between Cobb angles and fringe deviations in the W1 region (r = .64, p less than .05). Cobb and moiré angles were correlated in the upper O1 region (r = .60, p less than .05) and in the lower O1 region (r = .78, p less than .01). For major curves at or inferior to T10 (n = 13), the angles were correlated in the W region (r = .57, p less than .05). After one hour of training, three physical therapists averaged 87% accuracy in analyzing moiré fringe deviations. Complex moiré patterns, as observed in obese subjects or those with severe curvature, made fringe-deviation analysis unreliable. The most accurate moiré data were obtained at the approximate level of the apex of the scoliotic curve.
Comparison of roentgenography and moiré topography for quantifying spinal curvature.
The purpose of this study was to compare roentgenography and moiré topography for identification, treatment, and prevention of scoliosis at an early age. Moiré topography was used as an assessment tool for the quantitative examination of 12 children with mild-to-moderate scoliosis receiving physical therapy during a three-month period. Each child's roentgenogram also was analyzed independently by orthopedic physicians and radiologists using the Cobb method of measuring spinal curvature. Rho correlations of Cobb angles and the spinal curvature angles based on moiré photographs taken at weeks 4, 8, and 12 were found to be +.94, +.96, and +.93, respectively. The moiré method, thus, may be used as an available, inexpensive, and easily interpreted diagnostic and treatment tool in physical therapy.
Toe-walking in children with cerebral palsy: contributions of contracture and excessive contraction of triceps surae muscle.
The study was designed to provide a quantitative analysis of toe-walking in children with cerebral palsy (CP). The total internal moment developed about the ankle joint during locomotion and the passive component of this internal moment were measured. The contributions of the active and passive components were expressed as the ratio (R) between the passive moment and the total internal moment. Measurements were compared for 13 children with CP and 5 healthy children. For the data analysis, the children with CP, exhibiting apparently similar toe-walking, were divided into two groups: 1) Group CPI and 2) Group CPII. Group CPI was characterized by a small ratio R value, which indicated the presence of excessive contractions of the triceps surae muscle during locomotion. In Group CPII, the ratio R value was abnormally high, which indicated that a contracture (ie, structural change of the muscle or the tendon) was entirely or at least partly responsible for toe-walking. Each group requires a different therapeutic strategy.
Rapid and unbiased estimation of the volume of cutaneous malignant melanoma using Cavalieri's principle.
The Cavalieri volume estimator has been employed to determine the macroscopic tumor volume of 34 cutaneous malignant melanomas. With this rapid and unbiased method using histological specimens from slabs of known thickness, tumor volumes between 3.9 mm3 and 841.5 mm3 were found. The coefficient of error (CE) for tumor volumes ranged between 0.028 and 0.141, with a combined group CE of 0.043. There was a remarkably good correlation between tumor volume and maximal vertical tumor thickness estimated according to Breslow, with a correlation coefficient of r = 0.86 for all tumors, and of r = 0.82, if the one extremely big tumor is omitted. Both inter- and intraobserver variability was very low, with only approximately 1-2% difference. Thus, the method described allows for the reproducible, rapid, and unbiased estimation of tumor volume independent of the shape of the tumor.
Three-dimensional input of body surface data using a laser light scanner.
This article presents a device for automated input of three-dimensional body surface data using a laser light scanner. The device scans the surface in a few seconds. The data are available immediately in digital form for computer-aided presentation and analysis. Although the initial cost is moderately high, the cost per patient and processing time are low. This device makes possible the quantitative evaluation of plastic surgical procedures that are designed to alter body surface form.
Breast volume measurement of 598 women using biostereometric analysis.
A study of the volumes of the right and left breasts of 598 subjects was undertaken using biostereometric analysis. This measurement uses close-range stereophotogrammetry to characterize the shape of the breast, and is noncontact, noninvasive, accurate, and rapid with respect to the subject involvement time. Using chi-square tests, volumes and volumetric differences between breast pairs were compared with handedness, perception of breast size by each subject, age, and menstrual status. No significant relationship was found between the handedness, age, or menstrual status of the subject and the breast volume. Several groups of subjects were accurate in their perception of breast size difference. Analysis did confirm the generally accepted clinical impression of left-breast volume dominance. These results are shown to be consistent with those of a previous study using 248 women.
A longitudinal three-dimensional evaluation of the growth pattern in hemifacial microsomia treated by mandibular distraction osteogenesis: a preliminary report.
This study analyzed in three dimensions the longitudinal growth pattern of young patients with hemifacial microsomia (HFM) before and after mandibular distraction osteogenesis (DO). Six individuals with HFM (five boys and one girl; age at distraction, 12.5 +/- 2.4 years) were treated with similar procedures (surgery, type and direction of distraction, no functional orthodontic treatment before and after DO). Two individuals who did not undergo DO until late in their growth were used to compare growth patterns. In addition, one individual besides the six previously chosen sample in whom no DO was performed was also used to compare longitudinal growth patterns. Lateral and posteroanterior (PA) cephalograms were utilized preoperatively, spanning a period of 9 years. Computerized three-dimensional models were constructed from the lateral and PA cephalograms using a vector intercept algorithm. In the comparison group, for a period of 8 years on the affected side, the ramus height, body length, and total mandibular length increased at an average rate of 1.3, 1.9, and 3.0 mm per year respectively. On the unaffected side, the ramus height increased by 2.1 mm per year, 1.9 mm in the body, and 2.9 mm per year in total mandibular length. On average, the gonial angle on the affected side was increased by 1 deg per year, yet decreased by 1 deg per year on the unaffected side. The proportions between the affected to the unaffected side were maintained. In the six individuals 18 months after DO, it was found that the ramus height was reduced by 1.0 mm, whereas the body was found to resume its growth with a faster rate on the distracted side, maintaining its proportion. Angular changes demonstrated closing of the gonial angle on both the unaffected (0.5 deg) and distracted (3.5 deg) sides. Observed in three dimensions were the following: (1) On average, unoperated patients with isolated HFM tend to maintain their asymmetrical facial proportions and do not worsen substantially with time. (2) Different treatment effects were seen on the ramus, body, and total length of the mandible: changes in body length > ramus height > total length. (3) Eighteen months after DO, the correction was stable but with some degree of settling back from the initial overcorrection (< 5%). (4) Eighteen months after DO the mandibular body was found to have greater growth than the ramus. (5) Evaluating changes in three dimensions provides an improved understanding of the growth pattern and distraction effects on the mandible and its structural components. (6) Additional studies on the effect of mandibular distraction on other conditions involving mandibular deformities are required. In addition, the effect of various distractor devices should also be evaluated. Three-dimensional evaluation is recommended for improved accuracy.