Browsing by Author "Phillips, Ralph W."

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    A Study of the Effectiveness of Topical Fluoride Treatment Following the Removal of Direct Bonded Brackets
    (1976) Short, Steven T.; Garner, LaForrest D.; Kasle, Myron J.; Cunningham, Donald M.; Shanks, James C., Jr.; Barton, Paul; Phillips, Ralph W.
    In this investigation an attempt was made to determine what effect direct bonded attachments have on the posttreatment uptake of topically applied fluoride. Thirty-two freshly extracted mandibular central and lateral incisors were used. The teeth were cleaned, labeled and an adhesive tape window applied to the crown exposing a circular area one quarter inch in diameter on the labial surface. An initial enamel biopsy was performed to determine the fluoride content of the labial surface. Fifty percent phosphoric acid was applied for one minute to condition the teeth for bonding. A polycarbonate orthodontic bracket was then bonded with Sevriton resin and each tooth was stored for one week in water. After storage, the brackets were then removed and residual resin was cleaned off with a dental scaler. Half of the teeth were pumiced with flour of pumice for ten seconds. The teeth were observed microscopically to determine the condition of the labial surface. A 2% solution of sodium fluoride was applied to the teeth for eight minutes and the samples were then individually stored in water for one week. An enamel biopsy was performed and analyzed for fluoride, calcium, and phosphorus. A great deal of fluoride was taken up by the enamel surface on all the specimens. It was found that pumicing the teeth prior to the application of topical fluoride results in a significantly greater uptake of fluoride by the enamel surface. The results of this investigation indicate that a pumice wash following bracket removal facilitates a greater and more uniform uptake of topically applied fluoride on the surface of the teeth.
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    A critical clinical and television radiographic evaluation of indirect pulp capping
    (1967) Traubman, Lionel; Bixler, David; Shafer, William G.; Phillips, Ralph W.
    The purpose of this study was to quantitatively measure the rate and amount of calcification and secondary dentin deposition below deep carious lesions of otherwise radiographically and clinically sound teeth treated by calcium hydroxide - methyl cellulose indirect pulp capping. Standardized, reproducible serial radiographs of 50 treated young posterior teeth were exposed preoperatively at one, three, six, nine and, in some cases, 12 months. At the final appointment, the silver amalgam restorations were removed and all residual caries was excavated. A barium sulphate radiographic indicator paste identified the pulpal floor level at the first and last appointments. Ninety per cent of the teeth studied remained asymptomatic and were not pulpally exposed. Television density and linear measurement instrumentation was utilized to register calcification changes, pulpal floor thicknesses, and secondary dentin deposition. Following treatment, increased secondary dentin deposition and Calcification activity, or sclerosis, was initiated. Higher levels of calcification activity were related to increased thickness of pulpal floors, but this dimension had little influence on the total amount of reparative dentin formed. The rate of reparative dentin formation was highest during the first month and steadily diminished with time. Calcification activity experienced a cyclical change, or "exchange," with an initial activity peak. This was followed by an apparent, but temporary mobilization of mineral content •out of the affected dentin. With time, a steady rise in calcification level was observed. Measurement of longitudinal records showed that apparent pulp exposures can be avoided by allowing significant amounts of protective secondary dentin to form, before complete caries excavation.