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Biomedical subjects

K Collys

Publications and source records attributed to K Collys.

14 recordsLinked to original sources
PubMed2003

[Materials for mouth protectors].

Taking into account the number of teeth which are yearly irreversible traumatised during sport activities, the general use of mouthguards would contribute positively to the prevention of dental injuries. Custom-made mouthguards are more comfortable to wear and offer better retention and protection than stock and mouth-formed mouthguards. Different kinds of materials are available on the market for the construction of mouthguards. A polyethylene-polyvinylacetate copolymer (EVA) is the most suitable material. EVA allows the inclusion of hard or soft layers within the mouthguard. The thickness of a mouthguard is important for the reduction of applied forces to teeth: energy absorption capacity increases with material thickness. Increased thickness however, is associated with a reduction of comfort. Therefore, it is important that dentists take the patients' wishes and demands on both comfort and protection into consideration. A description of the clinical and technical method for the construction of a custom made mouthguard is given.

Absorption↗
PubMed2000

Risk of malnutrition in retirement homes elderly persons measured by the "mini-nutritional assessment".

BACKGROUND: The combined influence of age-associated factors such as general health, degree of dependency, diminished odor perception, and poor oral health on the risk for malnutrition was explored. METHODS: A total of 81 persons living in retirement homes took part in the study (mean age 83.4 years, SD = 6.6, range 61-98). The Mini-Nutritional Assessment (MNA) was used to evaluate the risk of malnutrition. Odor perception was measured by the detection threshold for isoamylacetate. The number of drugs taken by each person was counted. General health status was determined by the Medical Outcome Study (MOS) scores. Oral examinations were carried out to count the number of natural teeth and type of dentures. RESULTS: On average, women had slightly, but significantly, lower MNA scores than men (respectively, 23.4, SD = 2.8; and 24.6, SD = 2.6; p = .048). The correlations between age and MNA score and between odor perception and MNA score were not significant. Significant correlations were found between age and number of natural teeth (r = -.26, p = .001) and between MNA score and number of natural teeth (r = .27, p = .001). The mean MNA score of complete denture wearers (22.8, SD = 2.9) was significantly lower than that of partial denture wearers (25.8, SD = 2.9; p = .0005). The total MOS and MNA scores were not correlated, but a significant correlation was found with the subscales mental functioning (r = .29, p = .003), social functioning (r = . 19, p = .045), and perceived health (r = .19, p = .047). No relation was found between the activities of daily living (ADL) and MNA scores. A significant negative correlation was observed between number of drugs taken and the MNA score (r = -.34, p = .001). When participants without risk of malnutrition (MNA > or = 24) were compared with those at risk (MNA = 17-23.5), again, the number of drugs taken was significantly different (on average, respectively, 4.5, SD = 2.9; and 7.0, SD = 2.6; p < .0005). Using multiple regression to test the separate effects of the different independent variables, the number of drugs taken showed a significant negative regression coefficient (beta = -.31, p = .008), as did the mental health score (beta = .27, p =.02), giving a total R2 = .32. The other parameters did not contribute significantly. CONCLUSION: Among the elderly in retirement homes, the health state (as measured by the MOS subscale mental health and by the medication use) appears to be the most clinically relevant parameter to explain the risk for malnutrition. Loss of natural teeth and perceived health are less independently contributing, whereas no contribution derives from decline of odor perception, degree of dependency, and age itself.

Activities of Daily Living↗
PubMed1997

[Odor perception in relation to age, general health, nutritional status, and dental status].

Many studies have shown that odour perception declines with age. Considering the possible role of age-related phenomena such as general health, dental health and nutrition in such a decline, their joint effect on variability in odour perception was evaluated in the present study. 73 apparently healthy adults aged from 53 to 86 years (median age = 66), living in the community, took part in this study. The SENIEUR protocol was used to assess the general health status and anthropometric measures were obtained to assess the nutritional status. The sensory detection threshold for isoamylacetate (banana odour) was determined as the lowest detectable odour concentration. Dental status was assessed by a questionnaire on the presence of natural teeth and wearing of dentures. Those in poor general health had significantly higher mean odour thresholds (2.35, SD = 1.34), where threshold concentration was expressed as -log(mol/l), than those in good (3.47, SD = 1.46) or reasonably general health (3.75, SD = 1.02). Partial denture wearers had significantly higher odour thresholds (2.99, SD = 1.12) than those having only natural teeth (4.24, SD = 1.43). Significant correlations between age and anthropometrical values were found, indicating that with age, muscle mass particularly in women decreases (r = -0.50). Odour perception of women correlated significantly inversely with triceps skinfold thickness (r = -0.42), indicating that poor sense of small is associated with high body content of fat. Our results indicate that general health and dental state are important age-associated factors in odour perception. Since age does not show a significant independent effect, neither in an analysis of variance, nor in a multiple regression analysis, such factors tend to become more important than chronological age per se.

Aged↗
PubMed1996

Sensory detection of food odour in relation to dental status, gender and age.

The aim of this study was to investigate to what extent declining odour perception can be ascribed to dental status and oral hygiene habits, taking into account gender and age. Apparently healthy adults (n = 182), ranging from 53 to 93 years (mean age = 68.4) were tested. Information about oral hygiene habits (brushing teeth and cleaning dentures) and dental status was obtained by questionnaires. A validated objective procedure was used to measure sensory detection thresholds for isoamylacetate by an ascending method of limits. A significant negative correlation of odour perception with age was shown by the edentulous subjects which might reflect their wider age spread with many subjects over age 75. The evaluation of odour perception as a function of dental status shows no significant difference in odour perception between persons partial denture wearers, with natural teeth only or complete dentures. However, a tendency for lower odour perception was observed among male partial denture wearers, especially those reporting less frequent oral hygiene, which justifies further more detailed study.

Aged↗
PubMed1996

Variation in nutrient intake with dental status, age and odour perception.

OBJECTIVES: Since the proportion of elderly people with an insufficient intake of nutrients is high and many of the elderly have poor odour perception or poor dental state, in this study, the relation between age, odour perception, dental state and nutrient intake is explored. DESIGN: Single centre cross sectional study. SETTING: Independently living elderly were tested at their homes in 4 locations in Belgium, ranging in ages 60-90 y. SUBJECTS: 200 elderly participated in a 7 d food record study, resulting in 119 complete records. INTERVENTIONS: Food quantities were converted to nutrient intake levels. For all people, odour detection threshold was determined of isoamylacetate and dental status was noted. Path analysis was used and the separate effects of age, dental state, odour perception and gender were tested on macronutrient intake and micronutrient intake respectively. MAIN OUTCOME MEASURES: For all nutrients, no significant correlation was observed between nutrient intake and odour perception, except for energy, water, Fe and niacin (P < 0.05). A significant separate effect of odour perception was observed for water intake (CR = 2.09). Significant separate effects of dental state were observed for animal protein (CR = 2.29), niacine (CR = 2.04) and mono-unsaturated fats (CR = 2.32). CONCLUSIONS: Although odour perception and dental state can not fully explain variability in nutrient intake, our results show that people with poor odour perception have lower nutrient intake levels than people with good odour perception. Dental state may not be a direct cause of poor nutrition but a contribution factor in those elderly who have other risk factors.

Aged↗
PubMed1995

[Denture adhesives can be useful].

The use of denture adhesives has been discouraged by the dental profession. The negative attitude toward denture adhesives originates from scientific reports about the irreversible damage of denture bearing tissues caused by the application of denture pads and do-it-yourself liners. This survey of literature shows that, so far, no harmful effects have been reported about powder, cream or liquid denture adhesives. Therefore, it is justifiable to prescribe denture adhesives in some patients in order to improve their denture comfort. Dentists should be proactive in giving patients appropriate information about the different kinds of denture adhesives and in demonstrating their proper use.

Adhesives↗
PubMed1993

Rehardening of surface softened and surface etched enamel in vitro and by intraoral exposure.

The rehardening of surface-softened and surface-etched enamel was investigated in vitro and by intraoral exposure. Surface-softened enamel was obtained by treatment with 0.1 M acetic acid buffer solution (pH = 5.5) for 3 h. Surface-etched enamel was obtained by the acid etch procedure used in clinical situations (37% phosphoric acid gel, 30 s). The enamel lesions were treated in vitro, with calcifying solutions for 8 h or were carried for 48 h in an intraoral appliance. Changes at the enamel surfaces were investigated by surface microhardness measurements. Following the treatment with calcifying solutions a significantly greater indentation length was observed in surface-etched than in surface-softened enamel. No significant difference in indentation length between both types of enamel lesions was observed following intraoral exposure. It was concluded that the initial rate of rehardening between both types of enamel lesions is comparable. At his stage remineralization occurs in microspaces created in the slightly destroyed enamel structures. The influence of the etch pits on the indentation length becomes dominating when remineralization continues. An obliteration of etch pits was observed in enamel samples treated with the calcifying solution with the highest degree of saturation. It was suggested that freshly prepared highly supersaturated calcifying solutions can be used to enhance mineral appositions in accidental etch pits.

Acetates↗
PubMed1992

Load dependency and reliability of microhardness measurements on acid-etched enamel surfaces.

The load dependency of hardness measurements was investigated on sound and demineralized enamel samples. For all samples investigated, the Knoop hardness number (KHN) varied as a function of the applied load. Higher loads enhanced indenter penetration into the test surface. The variation in KHN values observed in demineralized enamel, both surface-softened and surface-etched, was explained by a decrease in porosity as a function of depth. The reading error for indentations made on surface enamel etched with 37% phosphoric acid gel for 30 s was found to be slightly elevated compared to indentations made on a polished sound enamel surface. It was concluded that the surface microhardness technique can be used for the longitudinal investigation of etched surface enamel.

Acid Etching, Dental↗
PubMed1991

Acid-etched enamel surfaces after 24 h exposure to calcifying media in vitro and in vivo.

The remineralization of acid-etched enamel lesions is investigated in this study both in vitro and in vivo over periods of 24 h. In an initial study, samples of etched bovine enamel were subjected in vitro to treatment with synthetic calcifying solutions, or were exposed to saliva by means of an intraoral appliance. Alterations in hardness of the enamel surface were measured by indentation techniques. In a second study the suitability of an impression technique for investigating the surface relief induced by an acid-etch procedure was investigated. Extracted human incisors were used to make SEM observations of eteched areas and corresponding sections of impressions. Subsequently, six subjects were selected for a clinical evaluation of the impression technique. Although a significant decrease in indentation length (increase in hardness) was observed for etched enamel lesions treated with calcifying solutions in vitro, no evidence for any such change was observed in samples exposed to the influence of saliva when investigated by the indentation and impression techniques.

Acid Etching, Dental↗
PubMed1991

Relation between lead in surface tooth enamel, blood, and saliva from children residing in the vicinity of a non-ferrous metal plant in Belgium.

Two groups of schoolchildren between seven and 12 years old residing in the vicinity of a non-ferrous industrial plant and exposed to lead (Pb) at a concentration that could cause health problems, were monitored. Concentrations of Pb in blood (blood-Pb), which were determined at regular six monthly intervals, were related to the Pb concentrations in surface tooth enamel (enamel-Pb). Acid etch biopsy samples of surface enamel were taken at the end of the five year study period in the first group (A) and after two years in the second group (B). Salivary Pb (saliva-Pb) concentrations were determined for the first study group on the same day that the enamel biopsies were performed. Calibration of the data was necessary--that is, blood-Pb concentration with respect to age and sex and enamel-Pb concentration with respect to etch depth and age. The blood-Pb concentrations declined with time. Surface enamel Pb concentrations correlated with blood-Pb concentration for the period starting with the pre-eruptive development of the incisors, related to blood-Pb concentration for a long time, and corresponded partly to the exposure at the time of pre-eruptive development and/or eruption. Through the correlation with enamel-Pb concentration, the seasonal behaviour of blood-Pb concentration became apparent. Saliva-Pb concentrations related to blood-Pb concentrations only in the short term.

Biopsy↗
PubMed1990

A comparison of the influence of lanthanum and fluoride on de- and remineralization of bovine enamel in vitro.

The influence of fluoride and lanthanum on enamel softening was compared by hardness measurements and by determination of the calcium content in the solution. The addition of lanthanum to an acetate buffer solution (0.05 mol/L, pH = 5.0) had no significant influence on the change of the indentation length and on the calcium release, compared with those of the control group. In the fluoride group, a moderate increase of the indentation length and a reduced calcium loss were observed. In a second experiment, surface-softened bovine enamel was treated with calcifying solutions (Ca/P ratio = 1.67). Differences in treatment were created by the addition of traces (2 ppm) of lanthanum, fluoride, or both. The acid resistance of the treated enamel was evaluated by two successive softening steps (0.1 mol/L acetate buffer, pH = 5.5). Alterations of the enamel surface were longitudinally followed with a hardness tester. The addition of fluoride, lanthanum, or both significantly improved the rehardening of surface-softened enamel, compared with that of the control group. A 2 x 2 factorial analysis of variance showed that lanthanum and fluoride had a highly significant main effect and a significant negative interaction effect on the rehardening of surface-softened enamel. Subsequent acid treatments revealed that only samples treated with a fluoride-containing solution were adequately protected from further dissolution. The enamel surfaces treated with a solution containing both lanthanum and fluoride were covered with an acid-resistant surface coating. SEM observation of this surface layer revealed the presence of globular and spherulite structures.

Analysis of Variance↗
PubMed1990

Interaction of magnesium and fluoride in the rehardening and acid resistance of surface-softened bovine enamel in vitro.

Surface-softened bovine enamel was submitted in vitro to a treatment with calcifying solutions containing calcium and phosphate (Ca/P ratio = 1.67). Variation in treatment was created by the addition to the solutions of magnesium, fluoride or both. Subsequently, the enamel samples were submitted to two successive softening steps. Alterations of the enamel surface due to the different treatments were evaluated with a hardness tester. No significant difference in the rehardening was observed between samples treated with a magnesium- or a fluoride-containing solution. A 2 X 2 factorial analysis of variance showed that both additions had a highly significant main effect on the rehardening. A significant interaction effect was obtained between magnesium and fluoride. Subsequent acid treatments revealed that only fluoride adequately protected the enamel surfaces from further dissolution. The presence of magnesium seemed to weaken the acid-protective action of fluoride in vitro.

Animals↗
PubMed1989

[Anticalculus dentifrices. A new era in preventive dentistry?].

Anticalculus toothpastes are available on the market. Toothpastes with Zinc compounds interfere mainly with the plaque formation. Dentifrices containing pyrophosphate give the highest reductions in calculus formation. The inclusion of pyrophosphate in a fluoride containing dentifrice did not interfere with the cariostatic action of fluoride on tooth enamel. The influence of anticalculus dentifrices on root caries and root hypersensitivity are, so far, not documented. Fundamentally, a lot of doubt still exists about the precise role of supragingival calculus formation in the onset of periodontal disease.

Dental Calculus↗