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Browsing by Author "Shanks, James J."
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Item Differences in Craniofacial Shape among A/J and C57BL/6J Mice and their F1 Crosses(2003) Roth, Lawrence E.; Hartsfield, James K., Jr.; Everett, Eric T.; Hohlt, William F.; Shanks, James J.; Ward, Richard E.Several studies have found relationships between various craniofacial measurements and the occurrence of cleft lip (CL) in humans as well as mice. Several modes of inheritance have been proposed, some of which involve a maternal effect. In this experiment, dried skulls of CL-susceptible A/J mice, CL-resistant C57BL/6J (C57) mice and Fl mice of the two reciprocal crosses of the same were measured and compared to ascertain whether differences existed between the two Fl strains, depending on the strain of the mother. AB6/F1J (AB6) have the Fl with A/J as the mother and B6A/F1J (B6A) have C57 as the mother. Digital photographs were measured using digitizing software. Groups of two measurements were combined to form ratios describing specific shapes. Measurements and ratios were analyzed using analysis of variance (ANOVA) and discriminant analysis (DA). Oneway ANOV A showed significant differences (p < 0.05) between the two parent strains with both the measurements as well as the ratios, with A/J being smallest and C57 largest in all measurements. Univariate ANOVA controlling for weight showed little difference from the oneway ANOVA. DA was able to correctly classify 100% of both parental strains into their correct strain category. Measurements between the two Fl strains showed fewer significant differences. The B6A strain was significantly smaller than the AB6 in 3 of the 7 measurements, and the tendency was for it to be smaller in all of the measurements. This placed the Fl strains closer to their paternal strain rather than their maternal strain. The only ratio which showed significant difference between the Fl 's was the premaxillary width to interorbital width in which the B6A exhibited a narrower premaxilla when compared with its interorbital width. This was again more like its paternal strain, though with the remaining 5 ratios, the Fl 's tended to be closer to their maternal strain. DA was able to correctly classify 89% of the Fl 's into their correct strain category, indicating significant differences in overall shape between the Fl 's. Lack of a strong maternal effect in this study may be do to the age of the mice examined and/or small sample size. Future studies may do well to use the euclidean distance matrix analysis to distinguish additional differences between the 4 strains.Item Quantification of Pain Thresholds in Orthodontic Patients Using Strain Gage Techniques(1992) Cordero, José Waldemar; Roberts, W. Eugene; Simmons, Kirt E.; Arbuckle, Gordon R.; Hohlt, William F.; Shanks, James J.The purpose of this study was to assess the suitability of a pain model that utilizes the application of force between teeth as the noxious stimulus. Also, the time course of pain threshold alterations in patients subjected to orthodontic treatment was explored. A simple pressure algometer utilizing strain gages was produced to apply and measure the force required to reach the pain threshold of incisor teeth (central-lateral pairs) for three consecutive days. Fifteen orthodontic patients were used (nine females, six males) with incisors in good alignment and with interproximal contact. Each patient was used for both control and experimental measurements in each arch. Baseline pain threshold measurements were taken on the first day and individual orthodontic springs placed on the experimental side. The control side was the adjacent central-lateral incisor pair on the other side of the arch where no spring was placed. Additional measurements were taken the second and third day in each quadrant. A great variability in pain response between patients was evident. Significantly lower pain threshold levels were observed a day after the initial spring activation followed by an increase in the pain threshold the second day after spring activation. In the mandibular arch, the treatment by day interaction was significant, with the experimental side pain threshold substantially lower than control on the second and third day. Pain thresholds in males were significantly higher only in the maxilla, although there was a tendency for lower pain sensitivity in males for both arches. An apparent crossover of sensitivity between arch sides was observed in this study. The present model was shown to be suitable to study pain thresholds associated with orthodontic forces, and the pressure algometer was able to quantify pain threshold with objective measurements. The model could be used clinically to screen patients with low pretreatment pain thresholds so modifications of treatment mechanics or pharmacologic means could be used to allay patient pain.