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Biomedical subjects

H C Jamison

Publications and source records attributed to H C Jamison.

At least 19 recordsLinked to original sources
PubMed1985

Relationship between enamel fluoride concentration and dental caries in a selected population.

The relationship between dental caries experience (DMFT) and enamel fluoride concentration (EnF) was determined in 100 freshman dental students aged between 20 and 26 yr. DMFT was determined by clinical examination and supplemented by bitewing radiographs. Biopsies were performed on the maxillary right canine of each student by etching with 1 M perchloric acid for 5 s. A regression analysis of DMFT and EnF and of square root DMFT and 1nEnF indicated that the correlation coefficients were not significant. Students exposed to fluoridated drinking water had significantly lower DMFT and significantly greater EnF than the students reared in areas with non-fluoridated drinking water.

Acid Etching, Dental↗
PubMed1982

Microleakage of conventional and microfilled composite restorative resins.

Microfilled composite resins have been introduced in clinical dentistry because of the difficulty in finishing conventional composite resins satisfactorily. Owing to the difference in coefficients of thermal expansion of the two resin systems, the objective of this in vitro study was to evaluate microleakage of a conventional and a microfilled composite resin. Class V cavities with butt cavosurface margins were prepared in the middle third of the facial surfaces of the crowns of 80 noncarious human premolar teeth; they were acid etched within the preparations only. Forty preparations were restored with Concise composite and forty with Silar microfilled resin. Ten teeth from each group were subjected to cyclic temperature changes between 5 and 55 degrees C for 1000, 2500, or 5000 cycles, respectively, and ten teeth from each group were not cycled (controls). After suitable preparation, the teeth were immersed in 45Ca solution for 18 h and contact radiographs were prepared. Microleakage was scored 0-3 at both the cervical and occlusal margins of the restorations. Microleakage was significantly greater at the cervical margins than at the occlusal margins. Differences within occlusal and cervical microleakages among the two resins were not significant.

Composite Resins↗
PubMed1982

Effect of cavosurface treatment on marginal leakage in class V composite resin restorations.

Under the experimental conditions used in this in vitro study, the following conclusions may be drawn: 1. Etching of the enamel walls in butt and beveled preparations significantly reduces incisal marginal leakage. 2. The application of a low-viscosity bonding resin to the etched enamel walls of preparations prior to the insertion of the composite resin is not necessary to obtain minimal incisal leakage at the composite resin/etched enamel interface. 3. Cavosurface configuration has no significant effect on incisal marginal leakage. 4. Cavosurface configuration and the restorative techniques used in this study affect the degree of gingival microleakage to some extent but do not eliminate it.

Acid Etching, Dental↗
PubMed1982

The apical seal via the retrosurgical approach. II. An evaluation of retrofilling materials.

In this investigation heat-sealed gutta-percha (A) reinforced with Adaptic (B), ASPA (C), Cupralloy without (D) and with (E) varnish, Spheraloy without (F) and with (G) varnish were used as retrofilling materials. Seventy maxillary central incisors with Class I canal anatomy were selected. Marginal leakage at the apical filling/root canal interface was evaluated quantitatively by means of a fluorescent dye technique. All statistical tests were computed at the 5 percent level of significance. Analysis of variance revealed that differences in microleakage among retrofillings were significant. Tukey's test of multiple contrasts was used to isolate statistically significant differences between all pairs of means. The following results were obtained: D F A G E C B Retrofillings are ranked in descending order of microleakage. Means that are linked were not significantly different.

Bisphenol A-Glycidyl Methacrylate↗
PubMed1981

Tensile and shear strengths of bonded and rebonded orthodontic attachments.

The objective of this study was to investigate the effect of a low-viscosity sealing resin and temperature cycling on the tensile and shear strengths of bonded and rebonded attachments. Eighty extracted noncarious human maxillary central incisors were used. The tensile bond strengths of a chemically activated bonding paste to etched enamel, with and without a low-viscosity sealing resin and with and without 500 temperature cycles between 5 degrees C. and 55 degrees C., were determined. The tensile bond strengths on rebonding were determined on the same teeth in such a way that the rebonded specimens were subjected to the same two variables as the originally bonded teeth. The shear bond and rebond strengths were determined on the remaining forty teeth. The specimens were tested to failure in an Instron machine. The bond strengths were expressed in MN.m-2. Analysis of variance was used to analyze the data. Temperature cycling adversely affected tensile bond and rebond strengths, while the sealing resin had no additional effect on tensile and shear bond and rebond strengths. Tensile versus shear and bond versus rebond strengths for similarly prepared specimens were not significantly different.

Acid Etching, Dental↗
PubMed1980

Dental caries prevalence in secondary school students in Iraq.

Caries data from 952 secondary school students in Iraq representing three geographic regions were obtained and analyzed on the basis of sex, geographic, and urban-rural differences. A DMFT of 5.47 and a DFS of 6.17 were recorded for the total sample. Greater caries experience was noted in urban residents, females, and those from the Central region.

Adolescent↗
PubMed1979

A study of the relationship of the dental midline to the facial median line.

This report presents the results of an original investigation designed to determine (1) the prevalence in the natural dentition of a maxillary midline located in the exact middle of the mouth using the philtrum as the most reliable guide and (2) the percentage of people in whom the maxillary and mandibular midlines precisely coincide with each other. Results indicate that the midline is situated in the exact middle of the mouth in approximately 70% of people and that the maxillary and mandibular midlines fail to coincide in almost three fourths of the population.

Adolescent↗