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Biomedical subjects

P E Schneider

Publications and source records attributed to P E Schneider.

At least 19 recordsLinked to original sources
PubMed1996

Biochemical comparison of plaque fluid on tooth and acrylic surfaces during a sucrose challenge.

Previous studies have investigated variations in dental plaque fluid composition within a single mouth after a sucrose exposure. The purpose of this study was to determine a potential source of calcium and phosphorus in plaque by comparing the pH, calcium and phosphorus concentrations in plaque fluid obtained from an acrylic appliance with samples taken from supragingival tooth surfaces within the same individual after a sucrose challenge. Separate plaque samples from 14 individuals were collected from an acrylic appliance or tooth surfaces within same individual before and 15 min after a 20% sucrose rinse. Each plaque sample was centrifuged and nanolitre samples of plaque fluid were analysed for pH with a pH microelectrode, for total calcium concentration by atomic absorption in a graphite furnace, and for phosphorus concentration by spectrophotometry. There was an increase in the calcium and phosphorus concentration in the plaque after the sucrose challenge and a significant increase in calcium and phosphorus concentrations in the plaque taken from the teeth compared to the acrylic surfaces. The results indicate that the increased total calcium and phosphorus in plaque during a sucrose challenge is probably derived from the demineralization of enamel or extracellular demineralized components.

Acrylic Resins↗
PubMed1995

Effects of caffeine intake during gestation and lactation on the acid solubility of enamel in weanling rats.

The purpose of this study was to evaluate the effects of dietary caffeine during gestation and lactation on the acid solubility of molar teeth of weanling rats. Nineteen pregnant dams were divided into two groups. The 9 dams in the control group were fed a 20% protein diet supplemented with caffeine (2 mg/100 g BW) throughout the experiment. At birth, 8 pups were randomly assigned to each dam. Pups were killed on day 22. The 1st and 2nd molars were removed from each pup's maxilla and mandible. Four randomly selected molars from each litter were placed in a chamber and bathed with a flow of acid solution and the amount of mineral dissolved from the enamel was determined. The results showed that the amount of dissolved Ca and Mg from enamel surfaces of 1st molars from rats in the caffeine group after exposure to acid was consistently greater than that of the non caffeine group. In the 2nd molars there was no significant difference between caffeine and noncaffeine groups. Scanning electron microscopy revealed an alteration of the enamel surface of the 1st molars of the caffeine group after acid exposure. These results indicate that caffeine intake during gestation and lactation would have a deleterious effect on dental enamel of 1st molars in newborn rats.

Animals↗
PubMed1991

Oral habits. A behavioral approach.

Thumb-sucking, pacifier use, and other oral habits are not so harmful or beneficial to the child to justify ill-timed aggressive discontinuance. Indeed there is ample time to guide the child to forming desired behaviors. In nearly every case success in habit management depends on the child making a personal commitment to discontinue the habit. Control can be placed in the child's hands after that decision is made.

Behavior Therapy↗
PubMed1991

Temporomandibular disorder in a child.

Temporomandibular (TM) disorders among children are uncommon. Their many etiologies include interferences with the formative process, malocclusion, and muscle disharmony. Facial pain, earache, headache, difficulty with chewing, and joint noise during mandibular function are symptoms. The two year course of a TM disorder that first became symptomatic in a six month old child is described.

Facial Asymmetry↗
PubMed1990

Effects of caffeine intake during gestation and lactation on bones of young growing rats.

The objective of this study was to evaluate the extended effect of caffeine intake received during gestation and lactation on the mandible and femur of rats. Timed-pregnant dams were divided into two groups. Dams of group 1 were fed a 20% protein diet throughout the experimental period from day 9 of gestation. Dams of group 2 were also fed a 20% protein diet, supplemented with caffeine (1 mg/100 g of body weight). Upon delivery, 8 pups were assigned to each dam, and the dams were continued on their respective diets. At weaning (day 22 postnatally), only male rats were selected. Pups of both groups were fed a 20% protein diet without caffeine. At day 56 postnatally the rats were killed. Mandibles and femurs were removed and the following parameters analyzed: weight, physical dimension, volume, and Knoop microhardness. Caffeine intake during gestation and lactation resulted in an impairment of femur growth and development and to a lesser extent mandibular growth and development. The early effects of caffeine in the maternal diet were lasting, as noted by the lack of recovery of the offspring even after changing to a caffeine-free diet for an extended time after weaning.

Animals↗
PubMed1989

Biocompatibility testing of an experimental fluoride releasing resin using human gingival epithelial cells in vitro.

Cell culture is a valuable method of evaluating the biocompatibility of new dental materials. The purpose of this study was to compare the in vitro biocompatibility of an experimental fluoride composite resin with fluoride and non-fluoride-releasing materials currently available. The dental materials tested were: MQ Silicate (silicate cement), KETAC-CEM and FUJI (type II glass ionomer cements), VISIO DISPERS (a light-cured, nonfluoridated, microfilled composite resin), and FR-17 (an experimental fluoride-releasing composite resin). The Smulow-Glickman (S-G) human gingival epithelial cell line, which exhibits semidifferentiated characteristics, was used in the study as a test system. Biocompatibility was quantified by counting the viable cells per unit area remaining after 24 and 48 h at two radial distances from cured specimens immersed in the cell culture medium. The test materials were observed to be most toxic to cells nearest the materials. A Time-Distance Cytotoxicity Index (TDCI) was calculated to relate the percentage of dead cells to viable cells at each diffusion distance for each exposure time compared to a nontoxic control. The relative toxicity ranking of the materials tested based on the TDCI was VISIO DISPERS (91%), FUJI (82%), FR-17 (30%), MQ Silicate (23%), and KETAC-CEM (10%), which exhibited the least toxicity. The cytotoxicity of the experimental resin FR-17 was within the range of cytotoxicity of currently accepted restorative materials.

Cell Survival↗
PubMed1982

Localization of tritiated 1,25-dihydroxy vitamin D3 in fetal rat mandible, kidney, and intestine.

In the fetal rat the specific uptake of this hormone appears in the kidney and in the mandible-tooth germ, but not by the intestine. Furthermore, uptake by the two former tissues was greatly influenced by gestational age. Localization in the mandible and tooth germ increased from approximately 50 DPM/mg wet weight of tissue on day seventeen of gestation to over 300 DPM/mg wet weight on the nineteenth day. A similar, but not as dramatic, increase occurred in the kidney. Thus, these data demonstrate: (1) the development of the specific uptake of 1,25-dihydroxy vitamin D3 in the kidney and bone with gestational age, and (2) the absence of specific receptive sites in the fetal intestine.

Animals↗