Biomedical subjects

E Kotsiomiti

Publications and source records attributed to E Kotsiomiti.

8 recordsLinked to original sources

PubMed2005

Factors related to the resting tongue position among partially and completely edentulous subjects.

The prevalence of abnormal (retracted) position of the tongue at rest was examined in subjects with varying number of natural lower teeth. The aim of the study was to explore the relationship between tongue retraction and state of dentition and to identify potentially related parameters. The resting tongue positions were recorded in subjects partially edentulous in the lower jaw (n = 164) and compared with those met in dentate (n = 57) and completely edentulous participants (n = 84). Potentially related parameters, such as age, sex, duration of edentulism, palate vault and signs of temporomandibular disorders were also recorded. Tongue retraction was observed in a small percentage (12.3%) of the dentate, almost half (45.7%) of the partially edentulous and in the majority (67.8%) of the completely edentulous participants. The number of natural lower teeth correlated with the resting tongue position in the partially edentulous group. The tongue position at rest was also found weakly related to signs of temporomandibular disorders in the dentate group and to the sex and duration of edentulism in the partially edentulous group. It was concluded that the abnormal positioning of the resting tongue is increasingly observed with decreasing number of natural teeth, possibly in accordance with the morphological and functional alterations that result from teeth loss. The presence of a retracted tongue affects the complete denture construction; however, its effect on denture function remains questionable.

Adult↗

PubMed2000

Resting tongue position and its relation to the state of the dentition: a pilot study.

The position of the resting tongue has been reportedly classified as normal or abnormal. The problems introduced by the abnormal tongue position relating to denture retention and stability have been sufficiently underlined. In the present study, the bibliography on the abnormal tongue position and its effect on denture function was reviewed. Additionally, the criteria for characterizing the tongue position as well the causes of the abnormalities, as reported in the literature, were discussed. Finally, a pilot epidemiological study was conducted, with the purpose to determine the incidence of the abnormal tongue position among edentulous patients as opposed to the dentate. The criteria used for the determination were criticized, and the mechanisms potentially leading to this habit were discussed. The findings indicate that the habit development is associated with the loss of natural teeth, therefore the mechanism relates to the functional and anatomical changes of the oral environment resulting from it. An epidemiological project has been designed, with the purpose of uncovering the associations between the observed tongue position and certain functional and anatomical features, as suggested by the present study.

Adult↗

PubMed2000

Removable prosthodontic treatment for the primary and mixed dentition.

Dental prosthetic treatment of children in the primary and mixed dentition years was planned with respect to the special conditions accompanying the absence of teeth. Besides the immediate functional and esthetic benefit of prosthetic therapy, the prosthetic appliance helps to maintain the oral functional status, which is considered necessary for undisturbed lower facial growth. Therefore, careful follow-up and thoughtful treatment decisions should be exercised, especially in cases where impairment of permanent dentition and supportive tissues complicate the prognosis.

Anodontia↗

PubMed1998

Weight and linear dimensional changes of reversible hydrocolloid duplicating materials: effect of storage and re-use.

Weight and linear dimensional changes of two hydrocolloid duplicating materials following setting in various environments were examined. Prior to the measurements, the sample materials were stored either in the sol or in the gel phase, for a period of 5 days, in order to evaluate the effect of ageing on their composition and behaviour. A 100% relative humidity environment produced the least change to the set material, and in this environment, the behaviour of the materials was not affected by their age. Results indicate that deterioration of the duplicating materials provoked by repeated or prolonged heating, is detectable, through their weight changes, even at an early stage.

Alginates↗

PubMed1997

Experimental wax mixtures for dental use.

Improvements in the properties of dental waxes were sought by alterations in their composition. Twenty-six blends of paraffin wax, beeswax and inorganic filler were subjected to the following tests: plastic deformation (flow), linear thermal expansion, elastic modulus and flexural strength. Flow tests were conducted in accordance with the corresponding ISO specification. Thermal expansion coefficients were estimated using thermomechanical analysis. Mechanical properties were tested using a universal testing machine. Pure paraffin and beeswax were used as controls. The results were subjected to analysis using correlation and regression. Regression coefficients in the range of 0.90-0.99 were obtained in most cases, flow tests exhibiting the highest coefficients and flexural strength the lowest. The incorporated filler particles reduced the flow of the natural waxes, especially of the ester-containing beeswax, and improved the elastic modulus and strength. Good correlation was found between the ingredient proportions and measured properties, suggesting a relationship between them, although this is quite complicated in the case of tertiary wax mixtures. The experimental blends exhibited properties that are potentially useful for a range of clinical applications.

Chemical Phenomena↗

PubMed1996

Waxes for functional impressions.

The aim of this study was to develop a wax suitable to serve as a functional impression material. Several binary mixtures of paraffin, beeswax and rosin were prepared. They were characterized by differential thermal analysis (DTA), and tested for plastic deformation, thermal expansion, detail reproduction and mechanical properties. It was found that the combinations of paraffin with rosin can function well as impression materials, as they combine a high value of plastic deformation at 37 degrees C with relatively low values at room temperature. Concentrations of rosin as small as 1% or 2% are adequate to produce this result. The flow of paraffin was significantly reduced by the addition of beeswax. A linear relationship was found between the 37 degrees C flow values of paraffin-beeswax mixtures and the proportions of the ingredients.

Dental Impression Materials↗

PubMed1995

Stability of dental waxes following repeated heatings.

The flow and strength properties of dental waxes were examined following excessive and repeated heatings of the materials. For one product, the flow at 40 +/- 0.5 degrees C was reduced by 25.3% following heating above 200 degrees C. A decrease of the elastic modulus at 20 +/- 1 degree C by approximately 66% was observed in some cases after the heating temperature had been increased to 300 degrees C. Property variations were related to compositional changes, which were investigated by infrared spectoscopy and thermal analysis. Exposure of dental waxes to temperatures higher than 200 degrees C, particularly if it is repeated, may affect the composition and properties, resulting in inferior materials.

Dental Materials↗

PubMed1994

Crown pattern waxes: a study of their behavior on heating and cooling.

The values of the critical physical properties, flow and linear thermal expansion, of crown pattern waxes were determined and compared with those reported by previous investigators. The method is one proposed by the American Dental Association, and measurements were conducted in the temperature range of 27 to 52 degrees C. At temperatures higher than 37 degrees C most of the materials tested exhibited flow values that although rather low seem to be suitable for laboratory use. As expected, the linear thermal expansion was considerable, ranging from 1% to 1.5% or more as the temperature was increased from 27 degrees to 47 degrees C. The arrest points of the cooling curves, which are indicative of the composition of the materials, were recorded and studied. The possibility of correlating the arrest points with the transition points observed on the flow and expansion curves was investigated. Although attempts have been made to improve them, the commonly used dental waxes are not yet entirely free of their known drawback of large and perhaps uncontrollable thermal expansion.

Chemical Phenomena↗