Bij het vervaardigen van conventionele volledige gebitsprothesen hanteren de meeste handboeken en onderwijsprogramma’s een protocol bestaande uit meerdere klinische stappen: anamnese, klinisch onderzoek, voorbereidende interventies, afdrukprocedure in twee fasen, relatiebepaling al dan niet met aangezichts- en gotische boog, passen in verband met esthetiek, plaatsing en nazorg (Kalk et al., 2001).

BACKGROUND:Chlorhexidine (CHX) varnishes have been mainly used for the prevention of caries in high-risk populations. Reports regarding their anti-plaque effect on a clinical level are limited to non-existing as opposed to their microbiological impact on plaque formation.AIM:The aim of this preliminary investigation was to evaluate the anti-plaque effect of two CHX varnishes applied on sound enamel in relation to a positive control, a negative control and to one another.METHODS:Sixteen healthy subjects volunteered for this randomized-controlled, single-blind, four-treatment-four-period crossover-designed clinical trial. A 3-day plaque re-growth model was used to determine de novo plaque accumulation following CHX rinsing, Cervitec application, EC40 application and no therapy. The amount of plaque was measured using the Quigley and Hein plaque index and "automatic image analysis" (AIA).RESULTS AND CONCLUSIONS:Varnish treatment resulted in significantly higher plaque levels than CHX rinsing irrespective of the varnish that was used (p< or =0.002), implying that the latter is likely to remain the gold standard as an anti-plaque agent. However, highly significant differences were also found in favour of both varnish systems when compared with no therapy (p<0.001), which indicates that varnish treatment is an effective means of inhibiting plaque formation in a short time span. Cervitec exhibited slightly, yet significantly, higher plaque levels in comparison with EC40 as determined by AIA (p=0.006). Large-scale trials with a longer observation period are necessary to substantiate these results.

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.

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.

In primary chick embryo cells aged in vitro, vaccinia virus replication is drastically inhibited by pretreatment with low doses of interferon. The antiviral state was established with doses about ten times smaller than those required with normal primary chick cells. Viral protein synthesis is also highly sensitive to chick interferon in these cells. Cell-free lysates from aged chick cells translated several viral and globin mRNAs efficiently. While drastic inhibition of vaccinia virus-specific protein synthesis by interferon treatment could be detected in the intact aged cells, the translation in the cell-free lysate was not significantly affected by pretreatment of the cells with interferon or interferon followed by infection with vaccinia WR.

Very few studies today validate the use of various sensory tools among elderly subjects, although the population is ageing rapidly. This chapter deals with applied sensory assessment in the food sector. It first presents heterogeneity factors in this population: physical and psychological health and dependency, decrease of chemosensory capacities, changes in oral-motor skills and modifications of cognitive abilities. Then, a study aiming at comparing the capacity of young and dependent elderly subjects to use a discrete scale (discriminatory power and repeatability) in a monadic sequential presentation is described. Finally, recommendations are given about the cases where a panel of elderlypeople should be required and the precautions to take during a sensory test with elderly subjects.

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.

Considering the possible role of age-related phenomena such as general health, dental health and nutrition in odour perception, their joint effect on variability in odour perception was evaluated in the present study. A total of 171 apparently healthy adults with a mean age of 66.0 years (S.D. 7.3), ranging between 53 and 86 years, 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 of the persons. The sensory detection threshold for isoamyl acetate was determined to measure odour perception. Oral examinations were used to assess dental status. Those in poor general health had lower mean values for odour perception than those in good or reasonably general health. Complete denture wearers and those with partial dentures had significantly lower values for odour perception than those with only natural teeth. Odour perception correlated significantly with measures of body fat and muscle mass, indicating that a poor sense of smell is associated with low body fat and muscle area. Our results indicate that general health and dental state are important age-associated factors in odour perception. Since odour perception is an important determinant of food consumption, early detection of diminished odour perception might be an indication of physical deterioration.

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 contributing factor in those elderly who have other risk factors.Sponsorship: This study was supported by the FLAIR and AIR programs of the Commission of the European Communities.

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.

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.

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.

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.

Sound and surface-softened bovine enamel samples were treated for 24 h with calcifying solutions (Ca/P ratio = 1.67) enriched with fluoride (0.5 or 1 mg/L), lanthanum (1 or 5 mg/L) or both. Lanthanum and fluoride containing calcifying solutions formed coatings on the enamel surfaces. The significant increase in indentation length observed in the sound enamel samples after treatment was related to the presence of the coating. The fluoride content of the acid-etch biopsy material, taken from enamel surfaces after treatment, was increased by the addition of lanthanum to fluoride containing calcifying solutions. This observation was made on both sound and surface-softened enamel samples.

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 etched 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.

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.