Browsing by Author "Tomich, Charles E."

Now showing 1 - 6 of 6
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    An Evaluation of the Bond Strength and Failure Site of Two Orthodontic Direct Bonding Systems
    (1979) Hyde, Kenneth R.; Garner, LaForrest; Tomich, Charles E.; Dirlam, James; Kasle, Myron
    Two commercially available orthodontic direct bonding systems were evaluated for ultimate tensile strength and failure site. Both Endur (Ormco Corp.) and Solo-Tach (L. D. Caulk Co.) are Bis-GMA resin adhesives, but only Endur required the use of a sealant prior to bonding. Metal brackets intended for use with Endur are backed by a thin stainless steel pad and fine wire mesh. Bracket bases for use with Solo-Tach were fully perforated stainless steel pads (GAC International, Inc.). Two hundred human bicuspid teeth were divided into four groups to test the four combinations of bracket and adhesive types. Half of each group was tested 30 minutes after bonding and half was tested after 3 weeks, with thermocycling in the final week. Failure sites were completely opposite for these two adhesives regardless of which bracket type was used. Endur (sealant and adhesive) failed primarily at the bracket-adhesive interface, while Solo-Tach (adhesive only) failed primarily at the enamel-adhesive interface. The sealant-adhesive seems to form a more tenacious bond to enamel. Mesh bracket bases formed a significantly (p<.025) stronger bond than fully perforated bracket bases with either adhesive. Some difference was still apparent after correcting for the difference in base area between mesh and perforated base types. No significant difference in tensile bond strength were found between the two adhesives or between 30-minute and 3-week tests. It was noted that several other factors, such as protection of oral tissues, working time, and ease of manipulation must be evaluated in chasing a satisfactory bonding system.
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    An Analysis of Possible Factors Affecting the Soft Tissue Response in Postadolescent Orthodontic Patients
    (1975) Cowan, Richard Edward; Garner, LaForrest D.; Potter, Rosario H.; Mitchell, David F.; Tomich, Charles E.; Hutton, Charles E.; Weinberg, R. Bernd
    This study was carried out to evaluate the factors which may vary the soft tissue response in non-growing subjects. Pretreatment and post-treatment lateral cephalometric radiographs of twenty-nine postadolescent orthodontic patients were measured with a sonic digitizer using facial plane as the reference. Stepwise multiple regression analysis was performed to select those factors from the original set of 6 according to the statistical significance of their contribution in the prediction of the soft tissue response. It was found that 30.84% of the horizontal upper lip response is due statistically to the maxillary incisor change and the pretreatment upper lip thickness at the vermillion border. This study also revealed that 67.76% of the horizontal lower lip response is due statistically to the mandibular incisor change, the pretreatment upper lip thickness at A-Point, and the mandibular postural change. Additionally, 16.50% of the vertical upper lip response is due statistically to the mandibular incisor change. Further, 33.39% of the vertical lower lip response is due statistically to the mandibular postural change and the pretreatment upper lip thickness at A-Point. Finally, the majority of the total variation in lip response is still not accounted for and therefore further research is needed.
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    A Cephalometric Investigation of Cleidocranial Dysplasia
    (1974-06) Davis, James Paul; Garner, LaForrest D.; Tomich, Charles E.; Bixler, David; Weinberg, R. Bernd; Dirlam, James H.
    The characteristics of cleidocranial dysplasia were first reported in 1897 by Pierre Marie and Paul Sainton. Since this first classification of the disease, many radiographic and clinical signs have been associated with this entity. Individuals with this disease have been repeatedly described as having a relative prognathism of the mandible due to a small, retropositioned maxilla and an enlarged cranial base. The present study was designed to determine, through the use of cephalometric measurements, if there is truly a difference in the size and position of the maxilla and an enlargement of the cranial base in these affected individuals. Ten cleidocranial dysplasia patients ranging in age from three years to 53 years, and their immediate families were studied. Non-affected members were studied to provide an intrafamilial comparison of skeletal development. The data obtained from the cephalometric measurements showed that the cranial bases for this group were within normal limits, or tending towards the small size. The maxilla was of normal size and the position was normal or anteriorly positioned in all cases. The mandible was considerably larger in 70% of the affecteds studied. Radiographic investigation showed this group to have delayed ossification of cranial sutures and mandibular symphysis. Absent frontal and mastoid sinuses, orbital hypertelorism, osteopetrotic appearance of the cranium, and absent or hypoplastic nasal bones were also observed.
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    A Histologic Investigation of Orthodontic Tooth Movement in Hypothyroid Macaque Speciosa Monkeys
    (1974) Davis, Steven L.; Garner, LaForrest D.; Barton, Paul; Tomich, Charles E.; Mitchell, David F.; Chalian, Varoujan
    This study was undertaken to histologically evaluate orthodontic tooth movement in hypothyroid and in normal Macaque speciosa monkeys. The experimental animals were rendered hypothyroid by radiosurgically altering the thyroid gland. A clinically acceptable orthodontic force was delivered to the anterior teeth of the monkeys. After the desired movement, a histologic investigation was made to correlate tissue responses with pressure, tension and root resorption. There was no significant difference among the three experimental animals. Likewise, there was no significant difference between the control animal and the three experimental animals. Osteoblastic and osteoclastic activity occurred to a comparable degree in both the experimental and control animals and was within normal limits for the amount of orthodontic tooth movement achieved. Root resorption was evident in both orthodontically treated and non-treated teeth in both the experimental and control animals. The root resorption observed was not significantly different, quantitatively or strategically, between the experimental and the control animals. Repair of root resorption was evident in both the experimental and control animals.
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    An Investigation of Depressive Root Movement in the Macaque Speciosa Monkey
    (1973) Clevenger, Victor Reid; Bixler, David; Mitchell, David F.; Tomich, Charles E.
    The purpose of this study was to investigate the possibility of accomplishing simultaneous intrusion and distal root movement of monkey premolar teeth utilizing the molar teeth as anchorage. Four Macaque speciosa monkeys were used as the experimental specimens. Root springs of the type used in the segmented arch technique were used to apply unequal moments to the premolar and molar teeth. The root movement was accomplished by a couple generated by the unequal moments. The results were analyzed cephalometrically and histologically. It was found that it is possible to accomplish distal root movement and intrusion of the monkey premolars when the anchorage is restrained from eruption. When the anchorage is not restrained intrusion is minimal. Root resorption was found to be associated with the magnitude of the difference in the moments applied and the amount of tooth movement.
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    The Response of Condylar Cartilage Stimulated by a Small Defect in the Rat Mandible
    (1983) Deguchi, Toshio; Kafrawy, Abdel; Tomich, Charles E.; Barton, Paul; Standish, S. Miles; Garner, LaForrest D.
    This study investigated the response of the condylar cartilage subjected to a small bone defect as a local stimulus in the rat mandible, in order to clarify one of the mechanisms of condylar cartilage growth. Fourteen male Wistar albino rats weighing 200 to 260 gm were divided into two groups, with two animals in a pilot study and 12 animals in the experimental group. Five male Wistar albino rats weighing 400 to 540 gm were used in a third group, which provided a basis for comparisons with the experimental group. To evaluate bone growth changes of the rat mandible, a superimpositioning method of tracings of the left and the right mandibles was done using the molars, incisors, anterior and inferior borders of the mandible. A sliding micrometer was used to measure each distance between the posterior edge of mental foramen (MF) and the posterior border of condylar process (CP) or angular process (AP). In the pilot study, one of two animals showed a decreased angular process and an increased condylar process, and the results suggested that the decreased activity of the masseter, resulting from dissecting a part of the masseter, may play an important role in changing the size or the shape of the rat mandible. In the experimental study, the masseter was not dissected and the results indicated that a hole drilled at the condylar notch did not stimulate condylar growth enough to be measurable. The third group showed that there were minor asymmetries between the left and the right mandible in normal rats, ranging from 0.49 to .0297 mm. Therefore, a larger sample size would be needed to arrive at definite conclusions.