Influence of the angles and number of scans on the accuracy of 3D laser scanning / 대한치과교정학회지

OBJECTIVE: To investigate whether the accuracy of 3D laser scanning is influenced by the angles and number of scans. METHODS: Using a 3D laser scanner, 10 manikins with facial markers were scanned at 7 horizontal angles (front view and at 20degrees, 45degrees, and 60degrees angles on the right and left sides). Three-dimensional facial images were reconstructed by 6 methods differing in the number and angles of scans, and measurements of these images were compared to the physical measurements from the manikins. RESULTS: The laser scan images were magnified by 0.14 - 0.26%. For images reconstructed by merging 2 scans, excluding the front view; and by merging 3 scans, including the front view and scans obtained at 20degrees on both sides; several measurements were significantly different than the physical measurements. However, for images reconstructed by merging 3 scans, including the front view; and 5 scans, including the front view and scans obtained at 20degrees and 60degrees on both sides; only 1 measurement was significantly different. CONCLUSIONS: These results suggest that the number and angle of scans influence the accuracy of 3D laser scanning. A minimum of 3 scans, including the front view and scans obtained at more than 45degrees on both sides, should be integrated to obtain accurate 3D facial images.

Decisional Conflict about Hormone Replacement Therapy in Postmenopausal Women and Its Related Factors

BACKGROUND: Since the Women's Health Initiative (WHI) study indicated that the significant risks are associated with hormone replacement therapy (HRT), it has been highly expected that postmenopausal women have decisional conflict about HRT. We investigated how much decisional conflict women have in taking HRT and what factors were associated with this conflict. METHODS: A total of 312 postmenopausal women, who had been on HRT or just began, were surveyed from May 10 to June 27, 2005. The subjects were asked by questionnaire that included demographic characteristics and factors related to decisional conflict. Decisional conflict was assessed using the Decisional Conflict Scale (DCS) composed of 16 items. RESULTS: The mean score of DCS was 2.61, which was severe and lack of support from friends and relatives was the most common major conflicting factor. Forty-five percent of the participants started HRT by doctor's recommendation, but had a higher decisional conflict compared to those who started on their own or by encouragement from family and friends. Women who were exposed to mass-media or who had discontinued HRT previously had a lower conflict. Higher the educational level and longer the duration of HRT before stopping lowered decisional conflict. DCS was not significantly influenced by age, income, menopausal symptoms, duration of HRT and the history of hysterectomy. CONCLUSION: Postmenopausal women when making a decision to begin HRT had high conflict. The factors related to conflict were educational level, exposure to mass-media, and motivation to begin therapy. Therefore, adequate and continued counseling with doctors may reduce women's decisional conflict about HRT.