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PubMed2002

Fit of cast commercially pure titanium and Ti-6Al-4V alloy crowns before and after marginal refinement by electrical discharge machining.

STATEMENT OF PROBLEM: Titanium has been suggested as a replacement for alloys currently used in single-tooth restorations and fixed partial dentures. However, difficulties in casting have resulted in incomplete margins and discrepancies in marginal fit. PURPOSE: This study evaluated and compared the marginal fit of crowns fabricated from a commercially pure titanium (CP Ti) and from Ti-6Al-4V alloy with crowns fabricated from a Pd-Ag alloy that served as a control. Evaluations were performed before and after marginal refinement by electrical discharge machining (EDM). MATERIAL AND METHODS: Forty-five bovine teeth were prepared to receive complete cast crowns. Stone and copper-plated dies were obtained from impressions. Fifteen crowns were cast with each alloy (CP Ti, Ti-6Al-4V, and Pd-Ag). Marginal fit measurements (in micrometers) were recorded at 4 reference points on each casting with a traveling microscope. Marginal refinement with EDM was conducted on the titanium-based crowns, and measurements were repeated. Data were analyzed with the Kruskal-Wallis test, paired t test, and independent t test at a 1% probability level. RESULTS: The Kruskal-Wallis test showed significant differences among mean values of marginal fit for the as-cast CP Ti crowns (mean [SD], 83.9 [26.1] microm) and the other groups: Ti-6Al-4V (50.8 [17.2] microm) and Pd-Ag (45.2 [10.4] microm). After EDM marginal refinement, significant differences were detected among the Ti-6Al-4V crowns (24.5 [10.9] microm) and the other 2 groups: CP Ti (50.6 [20.0] microm) and Pd-Ag (not modified by EDM). Paired t test results indicated that marginal refinement with EDM effectively improved the fit of CP Ti crowns (from 83.9 to 50.6 microm) and Ti-6Al-4V crowns (from 50.8 to 24.5 microm). However, the difference in improvement between the two groups was not significant by t test. CONCLUSION: Within the limitations of this study, despite the superior results for Ti-6Al-4V, both groups of titanium-based crowns had clinically acceptable marginal fits. After EDM marginal refinement, the fit of cast CP Ti and Ti-6Al-4V crowns improved significantly.

Alloys↗
PubMed2001

Statistical analysis of nutritional studies.

Statistical analysis of data collected in experimental or observational studies is an important part of nutritional research. If it is not done appropriately, there is a risk that information in the data is lost, or that conclusions are misleading. The present article does not attempt a full review of the subject of statistics, but attempts to list aspects where care is needed.

Analysis of Variance↗
PubMed2001

Usefulness of a psychometric questionnaire in exploring parental attitudes in children's dental care.

In this methodological study we investigated the usefulness and reliability of a questionnaire designed to capture 4 aspects of parental dental attitudes: dental knowledge, child oral health behavior, perceived importance of dental related aims, and parental responsibility. The study was undertaken in a group of 140 parents of schoolchildren aged 8-12 years from four comprehensive schools in Sweden. Test-retest reliability, quantified by the intraclass correlation coefficient (ICC) or by Cohen's kappa, varied from acceptable to excellent for different aspects of the questionnaire. The knowledge and responsibility-taking sections were also answered by a group of dental experts who showed a high level of internal agreement. Expert profiles, to which the parental assessments could be compared, were created. Exploration of the 4 aspects showed that this group of parents commonly had a multifocal view on the etiology and prevention of caries. Correlations between their knowledge assessments and the assessments made by the expert group varied from moderately negative to strongly positive. The parents revealed a high degree of dental-related motivation and responsibility, particularly according to oral health behaviors. In conclusion, the results indicate that this 4-part psychometric questionnaire might be a suitable instrument in investigations of priority and responsibility-taking as new aspects of parental dental attitudes, along with dental knowledge and child oral health behaviors.

Attitude to Health↗
PubMed2001

A 20-year longitudinal study of subjective symptoms of temporomandibular disorders from childhood to adulthood.

The aims were to study the development over 20 years of reported temporomandibular disorders (TMD) symptoms in an epidemiologic sample and to analyze possible correlations between these symptoms and some other variables. Four hundred and two randomly selected 7-, 11- and 15-year-old subjects were originally examined by means of a questionnaire with regard to symptoms of TMD. The investigation was repeated after 4 5, 10, and 20 years, using the same method. After 20 years, when the original group had reached the age of 27 to 35 years, 378 individuals (94%) could be traced, and they were sent a questionnaire. Three hundred and twenty subjects (80% of the original sample, 85% of the traced subjects) completed and returned the questionnaire. There was a substantial fluctuation of reported symptoms over the 20-year period. Progression to severe pain and dysfunction of the masticatory system was rare. On the other hand, recovery from frequent symptoms to no symptoms was also rare. At the last examination 13% reported one or more frequent TMD symptom. The prevalence of bruxism increased with time, but other oral parafunctions decreased. Women reported TMD symptoms and headache more often than men. Correlations between the studied variables were mainly weak. The highest correlations found (rs = 0.4-0.5) were those between reported tooth clenching and tooth grinding and jaw fatigue. It can be concluded that in this epidemiologic sample, followed over 20 years from childhood to adulthood, a substantial fluctuation of TMD symptoms was found. Severe symptoms were rare, but 1 of 8 subjects reported frequent TMD symptoms at the last exam.

Adolescent↗
PubMed2002

Effects of dental attendance frequency in heavy and low private care-using young adults.

In Finland, adults born in 1961 or later were progressively entitled to subsidies for dental care from private practitioners during 1986-90, while at the same time having access to care in the Public Dental Service. The aim of this study was to compare the effects of attendance frequency of private dental care on treatment costs and treatment spectrum for the heaviest and lowest users over a period. Three separate cohorts of recipients of reimbursements were formed, using the Social Insurance Register. The highest and lowest cost groups in 1986, 1990, and 1994 were followed up to 1997. Initially, the mean numbers of visits were 1.2-1.3 and 5.2-5.6 and cost Euro 48 53 and Euro 358-379 among low users and heavy users, respectively, in all cohorts. Among the heavy users (the high-cost category) infrequent attendance was related to higher and frequent attendance to lower mean annual costs of care. Among the low users (the low-cost category the opposite was true. Those who initially belonged to the high-cost category received in 1997 significantly more (P < 0.01) restorative treatment and, to a lesser extent, more (P < 0.01) preventive and periodontal treatment than those belonging to the low-cost category. Frequent dental care seemed to benefit those who received a lot of care. Frequency of attendance was not associated with being a low or a heavy user, indicating rigid check-up routines. The inclusion of simple oral health data would greatly improve the usefulness of the register as an evaluation tool for health-political decisions.

Adult↗
PubMed2002

Long-term fluoride release from a glass ionomer cement, a compomer, and from experimental resin composites.

The aqueous phase of glass ionomer cements enables fluoride ions to diffuse and to be released from the material. The matrix of resin composites is much less hydrophilic, and fluoride incorporated in the material is only released in small amounts. It was the purpose of the present work to study the influence of resin matrix formulation on the fluoride release from experimental, fluoride-containing resin composites. The resin composites were based on methacrylate monomers and the adduct of maleic anhydride and HEMA (2-hydroxyethyl methacrylate). The resin composites contained 1 w% or 5 w% of AlF3*3H2O. A glass ionomer cement and a compomer were used as controls. Five disks of each material were stored in distilled water at room temperature. By means of a fluoride sensitive electrode, the fluoride release from disk-shaped specimens was determined periodically over 3 years. The glass ionomer cement released the most fluoride (1.54 +/- 4 microg/cm2 after 1 year and 248 +/- 7 microg/cm2 after 3 years). The compomer released relatively little fluoride during the 1st year (30 +/- 1 microg/cm2) but after this time the rate of fluoride release became equal to that of the glass ionomer cement, resulting in a release of 122 +/- 8 microg/cm2 after 3 years. Regarding the resin composites, the fluoride release increased with the hydrophilicity and the acid character of the polymer matrix. The release, however, was significantly lower than that from the glass ionomer cement and the compomer and ranged from 1.2 +/- 0.07 to 42 +/- 3.9 microg/cm2 at 1 year and from 2.3 +/- 0.16 to 79 +/- 6 microg/cm2 at 3 years.

Aluminum Compounds↗
PubMed2002

Caries reduction in belgian 12-year-old children related to socioeconomic status.

This study compares dental caries reduction in Belgian 12-year-old children of different socioeconomic status in 1983 and 1998. Moreover, the relative effect of dental health factors on caries reduction is estimated. In the region of Brussels, children in the 7th grade at the same schools participated in cohort 1983 (n = 533) and in cohort 1998 (n = 496). DMFT, DMFS, and dental fluorosis were clinically recorded. The socioeconomic status of the children was established on the basis of their parents' education and profession. Data on children's home-based and professional dental health care habits were registered. Caries reduction was observed in both privileged and non-privileged children. However, non-privileged children, in cohort 1983 and cohort 1998, had significantly higher DMF scores than privileged children (P < 0.01). Dental fluorosis was more often identified in privileged children than in non-privileged ones. Most of the dental factors relating to children's home based and professional care were associated with caries reduction. Caries reduction was strongly related to socioeconomic status; non-privileged children registered lower than their counterparts.

Belgium↗
PubMed2002

Measurement and predictors of young adults' perceived ability to cope with dental life events.

The purpose of the present study was to assess coping skills and predictors of the ability to cope with dental life events employing a 10-item rather than a 48-item rating questionnaire. A representative random sample of 1490 subjects aged 25 years from 3 Norwegian counties received a mail questionnaire in March 1997. The response rate was 62% after 1 reminder. Eight selected items from the Social Readjustment Rating Questionnaire (SRRQ) plus 2 dental items were presented as graphic rating scales with the endpoints 'not difficult at all' and 'more difficult than anything'. Mean values were used to rank the life events and for comparison with findings from a previous study. Information was also collected for 16 predictor variables (Table 2). The informants found it moderately difficult to cope with losing one or more teeth and with getting dentures. A 10- and a 48-item rating scale seemed to give comparable results. In multiple logistic regression analysis, controlling for having experienced extraction during the previous 5 years, gender, and dental anxiety were significant predictors of both dental life events; education, many cavities, and belief in keeping teeth for life influenced coping with getting dentures. The identified predictors of dental life events explained <11% of the variance. In addition to extending the list of predictors of perceived need for skills to adjust to dental life events, the study also provided evidence to suggest that it may be acceptable to rely on a shorter rating questionnaire.

Adaptation, Psychological↗
PubMed2002

Number of teeth, body mass index, and dental anxiety in middle-aged Swedish women.

Risk factors for poor dental health include obesity, low socio-economic status, poor dietary habits, and dental anxiety. The aim of this study was to explore the complex relation between body mass index (BMI) and number of teeth in middle-aged women taking education, dietary intake patterns, dental care utilization, and dental anxiety into account. Three groups of women (37-60 years): reference women (group I, BMI 23.8 +/- 3.1 kg/m2), obese women (group II, BMI 35.0 +/- 2.6 kg/m2), and severely obese women (group III, BMI 41.0 +/- 3.4 kg/m2) were included. Questionnaires were used to assess education, smoking, number of teeth, dental care utilization, dental anxiety, dietary intake, and meal patterns. Age, education, and smoking habits did not differ significantly between groups. However, there were significant global differences in number of teeth (27.2 +/- 3.4, 23.0 +/- 9.2, 24.7 +/- 5.9) and reported daily energy intake (9756 +/- 3363 kJ, 10344 +/- 3850 kJ, 11970 +/- 3786 kJ in groups I, II, and m, respectively). In a multiple regression model, a lower number of teeth was independently associated with higher age, higher BMI, lower education, irregular dental care, high dental anxiety, higher energy intake, and lower iron intake. These variables explained 25% of the variation in number of teeth. In conclusion, BMI is an independent predictor of number of teeth in middle-aged women when socio-economic, dietary, and psychological factors are taken into account.

Adult↗
PubMed1978

Laboratory tests: basic concepts and realistic expectations.

Ordering and interpreting laboratory tests take familiarity with the concepts of normal limits, specificity, sensitivity, and prevalence. The relative importance of these test properties for clinical decisions is presented.

Clinical Laboratory Techniques↗