Browsing by Author "Mercer, Victor H., 1928-"

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    Dental developmental age versus chronological age as predictors of children's functioning in five developmental skill areas
    (1971) Barton, Douglas Harvey; Mercer, Victor H., 1928-
    The purpose of this study was to test the relationship between dental developmental age and chronologic age as they relate to other aspects of the child's development. The dental developmental age was determined on 74 children, 40 males and 34 females, ranging in age from two to 11 years. The sample population was chosen at random from patients at the Indiana University School of Dentistry. The socio-economic status was determined according to the North-Hatt Occupational Scale; 14.3 per cent of the children fell in the upper class, 84.3 per cent in the middle class, and 1.4 per cent in the lower class. Analysis by race showed that 71.6 per cent of the sample were Caucasian, 23.0 per cent were Negroid, and 5.4 per cent were Oriental. Panoramic radiography, with the S.S. White Panorex, was used to evaluate dental developmental age. Two independent observers scored the radiographs and double blind procedures were used. To determine dental developmental age, Wolanski's method of tooth formation evaluation was used. To determine functioning of children in five developmental skills areas, the Alpern-Boll Developmental Skills Inventory was used. Dental developmental age and chronologic age had a significant positive relationship to children's functioning in five developmental skills areas. There is a chronologic period when determination of dental age appears to be difficult. The data available and methodology for determining dental developmental age of the four-year-old female and the five-year-old male seems to be inadequate. Dental developmental age seems to be a better predictor of general developmental skills for males than it does for females, specifically in the two to eight-year-old group. The highest correlations were found in the youngest age group, i.e. the two to five-year-olds. The correlations between dental developmental age and chronologic age, and between those two indices and the five developmental skills ages remains highly significant in the younger ages but decreases consistently as the child becomes older. The specific age as well as the sex of the child has a definite effect on the correlations obtained. The use of dental developmental age is good but not superior to the use of chronologic age for predicting functioning for normal children. This may not be the case for atypical children. More study is indicated.
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    Formocresol pulpotomy in teeth of dogs with induced pulpal and periapical pathoses
    (1971) Kennedy, David B., 1946-; Mitchell, David; Garner, La Forrest Dean, 1933-; Kasle, Myron J.; Mercer, Victor H., 1928-
    Formocresol pulpotomy has been recommended for all infected primary molars irrespective of pulp vitality. Microscopic evidence is lacking when teeth with less than optimal pulpal preoperative conditions are treated. This study evaluated clinically, radiographically, and microscopically the effect of the five-minute formocresol pulpotomy in primary and permanent teeth of dogs with induced pulpal and periapical pathoses. Radicular pulps of 18 permanent and 12 primary teeth were exposed to the oral flora for 28 and 14 days, respectively, to produce pathoses that would contraindicate routine use of the pulpotomy. The five-minute formocresol pulpotomy was performed and nine permanent teeth were evaluated after four weeks and another nine after 12 weeks; the primary teeth were evaluated after 14 days. Eight permanent and four primary "control” teeth had their radicular pulps exposed to the oral flora for identical periods but were not treated by formocresol. In permanent teeth clinical success was 90 per cent, radiographic success was 30 per cent, and microscopic success of bloc sections was 10 per cent. The vital pulp reacted to formocresol by forming a homogenous band of markedly eosinophilic tissue, interpreted as "fixation;" very pale staining tissue was apical to this. A second area of marked eosinophilic tissue was in the apical part of all vital canals, apical to which was vital normal pulp. Similar trends were seen in the primary teeth. No "fixation," organization or repair was seen within any periapical lesion. The microscopic periapical appearance of related vital permanent and all necrotic canals indicated that formocresol pulpotomy is not particularly effective in teeth with induced pulpal and periapical pathoses. The findings suggest that it be used only under optimal clinical conditions.
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    A laboratory study of the adhesion of a restorative acrylic resin and a polycarboxylate cement on bovine enamel etched with fifty per cent phosphoric acid
    (1970) Lee, Brian Dalvin, 1942-; Gilmore, H. William (Homer William); Mercer, Victor H., 1928-; Garner, La Forrest Dean, 1933-
    The purpose of this laboratory study was to determine whether etching of flat bovine enamel surfaces with a 50 per cent aqueous solution of phosphoric acid for 60 seconds increases the bonding of a conventional restorative acrylic resin and a new polycarboxylate cement. The test specimens were subjected to 24 hours, 30 days and six months storage in water and then subjected• to temperature stress cycling and intermittent tensile stress cycling. A tensile test was used to measure the bond strength of both materials. The results of the Newman-Keul's test showed that pretreating the enamel surface with 50 per cent phosphoric acid significantly increased the bonding of the restorative resin, and that the cavity sealer supplied by the manufacturer further improved the resin attachment to enamel surfaces previously etched with phosphoric acid. The bonding of the resin to acid-etched enamel surfaces pretreated with or without the cavity sealer was unaffected by prolonged storage in water, temperature stress cycling, and intermittent tensile stress cycling. However, a significant reduction in the adhesion of the acrylic resin to polished-enamel surfaces pretreated with or without the cavity sealer was observed when the test specimens were subjected to the same testing conditions. The data obtained for the polycarboxylate cement test specimens showed that etching of the enamel surface with phosphoric acid also provided slightly higher adhesive values than the control specimens. Results obtained revealed that prolonged storage in water, and temperature and mechanical stress cycling did not affect the adhesion of the polycarboxylate cement to acid-etched enamel surfaces. However, thermal and mechanical stress cycling after prolonged storage in water appeared to decrease the adhesion of the cement to polished enamel surfaces. When Ca45 was used to assess the marginal seal of resin restorations placed into acid-etched Class V cavity preparations in extracted human teeth, the autoradiographs showed that etching of the cavity preparations with 50 per cent phosphoric acid improved the marginal seal of the restorative resin after one-week storage in water. When both the acid-etched and control restorations were thermal stress cycled 2500 times at a 40°C temperature differential, a slight improvement in the marginal seal of the acid-etched restorations was observed.