PubMed Health⌕ Search

SEARCH · PubMed Health

Results for “DENTAL MODELS”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 73 records · Page 4Linked to original sources
PubMed1976

[Results of experimental studies on new materials for dental models].

Newly developed cast materials (special stone plaster and plastic materials for single-stump casts) were tested for their setting behaviour and strength, their ability to reproduce fine-profiled surfaces and, in combination with standarized silicone impressions, for their dimensional behavior. With reference to the authors' experience, the suitability of these materials for making casts is critically evaluated.

Biophysical Phenomena↗
PubMed2000

Is modelling dental caries a 'normal' thing to do?

OBJECTIVE: To introduce and encourage the use of generalised linear models (GLMs) in analysing caries data that do not require the response to be treated necessarily as a sample from a normal distribution. BASIC RESEARCH DESIGN: At the present time, it is most likely that the sampling distribution of dmf/DMF in industrialised countries will not approximate normality. Generalised linear modelling can be conducted assuming many underlying distributions which, in fact, includes the normal distribution. In this paper three GLMs are employed (normal, Poisson, negative binomial) for modelling an example caries data set. In addition, a binomial model is used to model the dichotomous outcome of caries-free/caries-present. CLINICAL SETTING: The data comprised 871 Old Trafford, Manchester primary school children aged between 4 years 0 months and 5 years 11 months. RESULTS: The effect of one study covariate was prominent in a normal model applied to all available dmf data but not in two non-normal models which used dmf > 0 data only. Furthermore, the same covariate was significant at the 5% level in a binomial model indicating that it influenced whether or not caries was present and not the level of dmf. CONCLUSION: A suitable modelling approach for caries data is to employ a Poisson or a negative binomial model for the dmf/DMF response and a binomial model for the caries-free/caries-present outcome. This allows separate estimation of those factors which influence the magnitude of caries and those factors which influence whether caries is actually present or not.

Binomial Distribution↗
PubMed2004

Preserving the pipeline: a model dental curriculum for research non-intensive institutions.

Current advanced degree and research training programs no longer attract adequate numbers of students. The present system of dental education severely limits the appeal of these programs due to overcrowded curricula and clinical components that operate in an environment segregated from the academic/research enterprise. To make research-oriented education/training programs more accessible and increase the number of interested students, the culture of dental schools and dental education must change. Programs for future dental researchers and academicians must be supported by curricula that foster an appreciation of research/discovery, an interest in academic/research careers, and the application of biomedical/clinical advances to practice. The Marquette University School of Dentistry has designed a comprehensive new curriculum that supports student research and scholarly activity throughout all four years of dental education. The curriculum minimizes discipline-based courses and is structured into interdisciplinary content tracks that integrate biomedical, behavioral, and clinical sciences while emphasizing the application of science to patient care. A specific research/scholarly track represents dedicated didactic time that exposes all dental students to material not traditionally included in dental curricula. This track includes mentored research/scholarly experiences at local and national sites that are individually structured for each student. Customized student schedules facilitate participation in these experiences without hardship or penalty. This curriculum structure may serve as a model for research non-intensive institutions seeking to increase student interest in academic and research careers.

Curriculum↗
PubMed1994

System for the pH-dependent release of a dye in model dental restorations.

We are developing a system for detecting recurrent caries under dental restorations. The controlled release of dyes under conditions of likely demineralization will alert the dentist to potential secondary caries. Production of acidic species is a characteristic of caries activity; hence, the system uses pH-sensitive polymers to release markers when the pH at the cavity wall of the restored tooth is below 6.5. The objectives of this investigation were to test the hypotheses that (1) the proposed system can be designed to release detectable marker continuously for at least six months in a simulated carious environment, and (2) the transient pH changes in the oral cavity caused by simulated dietary intake will not induce premature marker release from the pH-sensitive polymer placed beneath restorations. Two types of dye-loaded microspheres based on styrene, vinylpyridine, and divinylbenzene were prepared and placed on the floor of model cavity preparations made from an acrylic rod. Each model cavity was restored with a hybrid dental composite, placed in a vial with 5 mL of sodium-lactate/lactic-acid base buffer solution, and stored at 37 degrees C. Solutions of three different pH values were used: 2.86, 4.73, and 6.39. The dye release into storage media was monitored periodically with a UV/VIS spectrophotometer. Results showed that the duration could extend beyond six months for pH > 4.73, and that transient oral pH changes are not likely to result in premature dye release. The data indicate that it would take approximately 21 days for the acidic agent external to the restoration to initiate dye release from restored sites.

Coloring Agents↗
PubMed1999

Hardness of model dental composites - the effect of filler volume fraction and silanation.

The relationship between structure and mechanical properties for dental composites has often proved difficult to determine due to the use of commercially available materials having a number of differences in composition i.e. different type of resin, different type of filler, etc. This makes a scientific study of any one variable such as filler content difficult if not impossible. In the current study it was the aim to test the hypothesis that hardness measurements of dental composites could be used to monitor the status of the resin-filler interface and to determine the efficacy of any particle silanation process. Ten model composites formulated from a single batch of resin and containing a common type of glass filler were formulated to contain varying amounts of filler. Some materials contained silanated filler, others contained unsilanated filler. Specimens were prepared and stored in water and hardness (Vickers') was determined at 24 h using loads of 50, 100, 200 and 300 g. Composites containing silanated fillers were significantly harder than materials containing unsilanated fillers. For unsilanated products hardness was independent of applied load and in this respect they behaved like homogeneous materials. For composites containing silanated fillers there was a marked increase in measured hardness as applied load was increased. This suggests that the hardness-load profile could be used to monitor the status of the resin-filler interface.

Journal Article↗
PubMed2000

Effects of an anticariogenic casein phosphopeptide on calcium diffusion in streptococcal model dental plaques.

Casein phosphopeptides (CPP) stabilize amorphous calcium phosphate (ACP) and may be used to localize ACP in dental plaque, maintaining a state of supersaturation with respect to tooth enamel, reducing demineralization and enhancing remineralization. The aim here was to investigate these effects by measuring the effect of CPP-ACP on calcium diffusion in plaque. Using Dibdin's effusion system, calcium diffusion was measured in streptococcal model plaques. This demonstrated that by providing a large number of possible binding sites for calcium, 0.1% CPP-ACP reduces the calcium diffusion coefficient by about 65% at pH 7 and 35% at pH 5. Hence, CPP-ACP binds well to plaque, providing a large calcium reservoir within the plaque and slowing diffusion of free calcium. This is likely to restrict mineral loss during a cariogenic episode and provide a potential source of calcium for subsequent remineralization. Overall, once in place, CPP-ACP will restrict the caries process.

Analysis of Variance↗
PubMed2004

Influence of pH and time on organic substance release from a model dental composite: a fluorescence spectrophotometry and gas chromatography/mass spectrometry analysis.

In this study we assessed the influence of pH and time on the degradation and elution of organic substances from the composite resin material, Z-100. To accomplish this, fluorescence spectrophotometry was evaluated as an appropriate technique for the identification of six organic substances (methacrylic acid, methyl methacrylate, hydroquinone, ethylene glycol dimethacrylate, triethylene glycol dimethacrylate and 4,4'-isopropylidenediphenol) that were eluted from resin composite material stored for 24 h or 6 months at pH 4.0, 6.0 or 8.0. In addition, complementary analyses (solid-phase microextraction/gas chromatography/mass spectrometry) were carried out to identify and quantify the substances. The main substances leached from the resin composite were methacrylic acid, triethylene glycol dimethacrylate and hydroquinone. It was concluded that fluorescence spectrophotometry seems to be a suitable, non-destructive technique for the qualitative analysis of eluted organic components. Critical combinations of time and pH allowed the elution of several organic substances, predominantly methacrylic acid, triethylene glycol dimethacrylate and hydroquinone, from the model resin composite, Z-100.

Acrylates↗
PubMed1993

The COMMIT dental model: tobacco control practices and attitudes.

The National Cancer Institute's program to help dentists reduce tobacco use among their patients is part of the Community Intervention Trial for Smoking Cessation, a 22-community, randomly controlled trial of an intervention program for smoking cessation. Results of COMMIT baseline surveys of dentists in the 11 intervention communities are presented.

Community Health Services↗