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K J Showfety

Publications and source records attributed to K J Showfety.

10 recordsLinked to original sources
PubMed1987

Repeated measures analysis of geometrically constructed and directly determined cephalometric points.

Cephalometric landmarks were directly determined visually from bony anatomy on lateral cephalometric radiographs and compared with geometrically constructed cephalometric landmarks for repeated measures reliability of identification. Three groups of four orthodontists, grouped by level of experience, identified 18 landmarks on each of four cephalometric radiographs. This measurement procedure was repeated four times in 1-week intervals. The variability, main associations and interactions among the variables of tracer experience, quality of radiograph traced, and the anatomic landmarks traced were assessed by means of the repeated measures analysis of variance and follow-up Tukey HSD test. The coefficient of variation was used to compare the relative variability of replicate identification of the 18 cephalometric landmarks. Rank order and statistically significant groupings by variability are listed. The level of observer experience and quality of radiograph were statistically unrelated to landmark variability on replicate examination. The geometrically constructed landmarks tested were not statistically different from the reliability of the directly determined bony-based landmarks. This finding would lend support to the techniques of geometric construction used in the Ricketts cephalometric analysis.

Cephalometry↗
PubMed1986

Bonding characteristics of impacted versus erupted permanent teeth.

Erupted and impacted teeth from young (12 to 24 years of age) and older persons (over 50 years of age) were bonded by a standard technique using etching times of 0, 15, 30, and 60 seconds. Two subgroups of teeth were soaked for 7 days and compared with those in the remainder of the group. Test specimens were loaded in shear to bond failure by means of a testing machine with a 200- kg load cell and a crosshead speed of 5 mm/minute. Results indicated insignificant bond-strength differences between young-impacted and young-erupted teeth for any given etching time. Very small bond-strength differences were found for various etching times (15, 30, and 60 seconds). A significant difference was found between 24-hour soak and 7-day soak for the etching times of 30 and 60 seconds only.

Adolescent↗
PubMed1983

Adaptation of head posture in response to relocating the center of mass: a pilot study.

Relationships have been established between head posture and craniofacial morphology in both adults and children. The determinants of head posture are not yet understood. Does posture dictate form, or vice versa? This pilot study investigates the short-term effect of artificial forward relocation of the center of the mass of the head on postural adaptation in the sagittal plane. The observed responses are not systematically uniform and, in fact, are characterized by a lack of consistency and a high degree of intra- and interindividual variability.

Adaptation, Physiological↗
PubMed1983

A simple method for taking natural-head-position cephalograms.

Standing natural head position is a reproducible, physiologically determined aspect of function. Recent studies have demonstrated associations between this aspect of function and the form of the skeletodental features, in both growing and nongrowing persons. A simple method has been devised which obviates the need for multiple radiographs to determine the clinical reliability of the method. The device, its construction, and method of use are described.

Cephalometry↗
PubMed1980

Experimental manipulation of head posture.

Variations in natural head position have been noted by previous workers to be associated with both dentoalveolar and craniofacial skeletal morphologic features. The determinants of cranial posture are as yet not known. Three experiments are described, dealing with the influence of (1) total nasal obstruction, (2) visual feedback deprivation, and (3) a combination of (1) and (2) on the posture of the cranium measured relative to a gravity-defined true vertical reference plane. The results indicate that total nasal obstruction results in all cases in an extended head position. Visual deprivation produces adaptation of a smaller magnitude and unpredictable direction. Combination of both experimentally induced conditions indicates a dominance of the respiratory adaptation in terms of postural response to these stimuli.

Adaptation, Physiological↗