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Biomedical subjects

F R von der Fehr

Publications and source records attributed to F R von der Fehr.

At least 19 recordsLinked to original sources
PubMed2000

Performance of tunnel restorations at 3-6 years.

OBJECTIVES: the purpose of this study was to evaluate the success of the tunnel restoration method in the Norwegian public dental service. METHODS: all patients from three age cohorts (born 1975-1977) who had received one or more tunnel restorations at least 3 years earlier, at the public dental clinic in Kongsberg and a neighboring clinic in Numedal, were examined clinically and radiographically by two calibrated dentists. Individuals with two or more filled surfaces per year were classified as "caries active". The statistical analyses consisted of non-parametric Kaplan-Meyer estimates of the survival function, and rank tests for associations to the longevity data and the background variables. RESULTS: a total of 182 restorations in 94 patients were studied. Sixty-five percent of the restorations were considered successful. A total of 118 restorations were censored within the 76-month observation period. The median survival time was estimated to be 55 months, with a 95% confidence interval of 51-61 months. About 90% survived 3 years, while only 35% survived 5 years. Both caries activity and operator had significant effects on the survival period. On the other hand, there was no difference between "wells" and "tunnels", tooth type, tooth surface or jaw with regard to success rate. CONCLUSIONS: The tunnel preparation filled with currently available glass-ionomer cement is not a generally favorable alternative in primary approximal lesions. However, in the hands of a well-trained, careful operator it may be chosen as a semi-permanent solution for patients with modest caries activity.

Cohort Studies↗
PubMed2000

Dental caries and sugar intake of children from rural areas with different water fluoride levels in Paraíba, Brazil.

UNLABELLED: Few reports have investigated caries prevalence in rural areas of Brazil. OBJECTIVE: The aim of this study was to observe the caries prevalence (DMFT, DMFS) in 12-year-old children living in rural villages of Paraíba, Brazil with low and moderate fluoride levels in the drinking water and to relate it to sugar intake and oral hygiene. METHODS: One hundred and ninety four children from 13 villages were grouped according to the water fluoride levels: low fluoride (LF, <0.2 ppm F, 96 children) and moderate fluoride (MF, 0.7-1.0 ppm F, 98 children). Caries and oral hygiene (OHI-S) were scored according to WHO criteria. Sugar intake was assessed through interviews. A sub-set of subjects (n=23) from the LF group was re-examined 2 years later. RESULTS: For the LF and MF groups the DMFT (mean, SD) observed was 3.9 (3.7) and 2.5 (2.1) respectively, the DMFS was 9.2 (10.6) and 5.4 (5.7). Both indexes (DMFT, DMFS) showed significant differences (P<0.01, Mann-Whitney U-test) according to the fluoride levels in the drinking water. The mean increment of caries in the sub-set group of subjects was approximately 1.5 surfaces per subject/year. The reported sugar intake was low for both water fluoride groups (P>0.05). In a regression analysis the water fluoride levels, the use of fluoridated toothpaste and oral hygiene index were related to DMFS (R2=0.08, P< or =0.05). CONCLUSIONS: Caries prevalence was lower in MF than in LF rural areas of Paraíba. Caries and sugar intake seems to be lower in rural areas than in urban areas of Paraíba with similar fluoride levels in the drinking water.

Brazil↗
PubMed1999

Clinical performance of indirect composite resin inlays/onlays in a dental school: observations up to 34 months.

The aim of this retrospective clinical study was to evaluate the clinical performance of indirect composite resin inlays and onlays. Patients among the dental school clientele in need of posterior approximal filings and preferring esthetic restorations were included. Clinical teachers or trained students under supervision carried out the preparations, made impressions and prepared stone casts. Inlays made from either Tetric, Z100 or Maxxim were light-cured and placed in a light oven for secondary curing, before being luted with a dual cure cement. At recall, the inlays were evaluated using slightly modified US Public Health Service (USPHS) criteria. Twenty-two patients with 50 fillings presented for the assessment. The right censored observation periods ranged from 12 to 34 months, with a mean of 20. With the only exception of an early fracture of one onlay, all restorations were classified as successful. This was based on 15 "A" (optimal) and 34 "B" (acceptable) ratings, each of which representing the lowest rating for the individual restoration. The major reason for the "B" ratings was imperfect gingival marginal adaptation due to a small surplus of bonding material and/or luting cement.

Adult↗
PubMed1998

Saucer-shaped cavity preparations for posterior approximal resin composite restorations: observations up to 10 years.

OBJECTIVE: This clinical trial aimed at studying the long-term performance in routine clinical practice of saucer-shaped Class II resin composite restorations. METHOD AND MATERIALS: Fifty-one preparations were completed and filled with either of two light-cured posterior composites by seven dentists of the Public Dental Service. The restorations were evaluated annually, using the US Public Health Service criteria, bitewing radiographs, and dies based on replica impressions. At the final evaluation, the recall rate was 100%. RESULTS: After a mean of 7.2 +/- 1.3 years of service (censored maximum of 9.6 years), 70% of the restorations were acceptable for continued use. Caries and technical deficiencies were the main causes of failure. CONCLUSION: The saucer configuration, by respecting and utilizing inherent properties of the resin composites, spares sound dentin and is preferable to the box preparation.

Adolescent↗
PubMed1997

The start of caries decline and related fluoride use in Norway.

The objective was to determine the start of caries decline and to estimate the use of fluorides about this time. The material consisted of service reports from the Norwegian municipal School Dental Services (SDS) and the country-based Public Dental Service (PDS), literature reports, private sales and marketing statistics, and a national health survey. The national data for the permanent dentition demonstrated a distinct decline in the average number of filled tooth surfaces from around 1970. Counties were grouped as "early", < or = 1970, and "late", > or = 1971. The 5 "early" countries showed the decline to be evident in 1968. Several local districts reported caries reductions since 1963, following the implementation of fluoride programs. Altogether, there was a steady increase in the % of schoolchildren taking part in organized brushing or rinsing programs from 1960. In 1970, 60% of the schoolchildren regularly took part in the supervised fluoride programs. From September 1971, 0.1% fluoride dentifrices became generally available over the counter in retail stores. In 1972, 32-54% of all toothpaste delivered or sold was fluoridated. The distinct time interval between the caries decline and the availability of fluoridated toothpaste rules out the possibility of an interaction before 1971. The extensive activities with fluoride-based preventive programs in the SDS and PDS have probably been the major factors behind the decline in the late 60s/early 70s.

Adolescent↗
PubMed1996

Approximal cavitation related to bite-wing image and caries activity in adolescents.

Cavitation of enamel lesions probably represents a significant step regarding further progression of the caries process. The primary objective of this study was to examine in adolescents the macroscopical appearance of approximal surfaces with radiographic lesions and relate this to the caries activity of the individual. A second objective was to establish the clinical feasibility of a modified technique for inspection of approximal contact surfaces. The material consisted of 46 enamel lesions selected on the basis of routine bite-wing radiographs of 140 patients aged 17-18 years, available from the Public Dental Service of Lillehammer, a non-fluoridated town. Lesions close to or approaching the AD junction were classified as D2 lesions, whereas those demonstrating a shadow not more than 1 mm into the dentine were designated D3 lesions. Based on recorded treatment during the last 3 years, patients were dichotomised as caries-active (CA) if they had more than 6 new lesions involving the dentine. The remainder with little or no activity were designated modestly active (MA). A small orthodontic rubber ring was placed around the contact point of the approximal surface of interest 1 day before an impression was taken. A separation of 0.5 mm facilitated cleansing and injection of low viscosity impression material (Xantopren(R) L, Blue, Bayer Dental). Discontinuity in the approximal enamel surface, determined by visual inspection of stone dyes, prepared from the impressions, was classified as cavitation. The results demonstrated that in MA patients D2 lesions seldom had cavities while in CA patients cavitation was usually found both in D2 and D3 lesions. The feasibility of the impression/inspection method seems established. It is easily performed and should be considered as a diagnostic tool in borderline cases.

Adolescent↗
PubMed1996

Fluoride release and uptake in vitro from a composite resin and two orthodontic adhesives.

The aim of this study was to investigate the fluoride release and uptake characteristics of a composite resin (Tetric) and two orthodontic adhesives (VP 862 and Saga Bond), with a type-II glass ionomer cement (Ketac Fil) as a control. Test specimens in 2 ml deionized water released fluoride over a period of 33 days. Ketac Fil released 54 and 15 times more fluoride than Tetric after 24 h and 1 month, respectively, whereas the two adhesives released amounts between these values. Specimen exposure to 1000-ppm NaF solution increased the 24-h fluoride release from all materials, with near pre-exposure levels reached after 2-3 days. Ketac Fil had a tendency to recharge not seen with the other materials. The ytterbium trifluoride filler in Tetric has a very low water solubility, and it is therefore suggested that the increases in fluoride release from Tetric after exposure to fluoride were most probably due to release of surface-retained fluoride.

Adhesives↗
PubMed1995

Caries treatment through 30 years in children and adolescents in Asker, Norway.

Asker is a capital suburb where a preventive philosophy has guided the public dental health services for decades. In the period studied the child population aged 3-13 yr increased from 3208 to 6008. In the school age groups 7-15 yr practically all children in the community have participated in the dental service programs. The objective of the paper is to present retrospectively the changes in caries status of children under near optimal dental health care conditions and to expose reported preventive activities. A considerable increase in the proportion of "caries free" pre-school children occurred in the period 1976-88. A maximum was reached in the latter part of the eighties, whereafter a leveling off is suggested. For school children a rapid increase in "caries free" children took place for the lowest grades, starting before 1976. The higher grades came later and at a slower pace. The great number of fillings inserted in 1966-72, oscillating around 60 surfaces for the nine school years, decreased rapidly during the following decade and seems now to have settled around a total average of five to six surfaces. This implies a reduction of 90% in 20 yr. In most age groups these changes started before 1970. The major part of the caries decline occurred in the seventies and a leveling off is apparent during the eighties. The average number of filled surfaces per year has fallen from 6.6 in the 1955 birth cohort to 0.7 in the 1977 cohort, a reduction of 89% in 22 yr.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1994

Caries prevalence in the Nordic countries.

Despite differences in the dental health care services and the recording and reporting systems, a consistent and similar decline in dental caries is evident for Denmark, Finland, Norway and Sweden during the last two decades. Iceland has experienced a later onset but a steeper decline in dental caries than the other Nordic countries. Public reports demonstrate that in 1991/92 23-49 per cent of the 12-year-old children were caries-free and the mean tooth prevalence was 1.2-2.5 DMFT. Fluoride in various forms has been instrumental in these changes, and public dental health programmes appear to have played an important role, at least in the initiation of the decline. Caries has been slowed down and delayed, but has not been eradicated.

Adolescent↗
PubMed1993

Saucer-shaped cavity preparation for composite resin restorations in class II carious lesions: three-year results.

This study determined the feasibility of saucer-shaped cavity preparations for composite resins in class II lesions. Saucer-shaped class II cavity preparations were restored with composite resin and subjected to clinical, radiographic, and replica cast evaluation (39 restorations) after 6, 18, and 36 months. The results indicated that the retention, resistance form, and wear resistance of the class II saucer-shaped cavity preparations were satisfactory after 3 years.

Acid Etching, Dental↗
PubMed1992

Caries prevalence of kindergarten children in Salzgitter and Oslo.

In a comparable epidemiological study of kindergarten children, 455 4- and 5-year-olds in Salzgitter (FRG) and 171 4- and 5-year-olds in Oslo (Norway) were examined. Caries was scored at the cavitation level according to WHO criteria. The percentage of caries-free children was higher and the dmfs scores were lower in Oslo than in Salzgitter. It is postulated that this was the result of different levels of fluoride exposure, nutritional habits and dental treatment provision.

Child, Preschool↗
PubMed1990

[Preservatives and dental caries. Can preservatives in food and beverages influence oral health?].

There has been a pronounced decline in dental caries in industrialized countries during the last decades. The most obvious explanation is exposure to fluorides. However, the decline started before fluorides were extensively used. Theoretically, a contributory factor may have been increased consumption of foods containing preservatives. The aims of the present study were to find out whether increased intake of preservatives has occurred, and to assess the effect of two commonly used preservatives, sorbic acid and benzoic acid, on bacterial growth and on plaque acidogenity in vivo. Results from five consumption reports from the Central Bureau of Statistics of Norway were used to estimate changes in consumption of basic foods containing the preservatives mentioned. A modified broth dilution method was used to determine the growth inhibitory effects on selected oral streptococci. Plaque-pH measurements were performed with a microelectrode to assess possible effects on acid production. Data pointed towards increased consumption of preservatives. Legal concentrations of preservatives inhibited bacterial growth. Similar concentrations of the preservatives had a negligible effect on acid production in dental plaque (0.4% W/V), whereas higher concentrations (2% W/V) had an inhibitory effect.

Benzoates↗
PubMed1981

Oral hygiene and caries. A review.

On the basis of existing literature, efficient oral hygiene was found to have a caries preventive effect. The quality of the cleaning appears to be more important than the frequency of its performance. Professional tooth cleaning at regular intervals may inhibit caries on all tooth surfaces. The effect of self-performed oral hygiene has been demonstrated mainly on free smooth surfaces and on front teeth.

Adolescent↗
PubMed1980

Two-year study on the effect of professional toothcleaning on schoolchildren in Oppegård, Norway.

A longitudinal study on the effect of a preventive program based on bimonthly professional toothcleaning and hygiene instruction was carried out on 293 schoolchildren from the 1st, 4th and 7th grades. The prophylactic paste used contained 0.8% sodium monofluorophosphate. The control groups brushed with a 0.2% sodium fluoride solution four to five times during each school year. After 2 years the Visible Plaque Index and the Gingival Bleeding Index were significantly reduced for all grades in the test groups as compared to the controls. The percentage of children without new caries lesions increased significantly from an average of 50% in the control to 71% in the test group. The mean caries increments during the 2 years, excluding occlusal surfaces, were 0.22, 0.28 and 1.20 in the three test groups. This represents an average caries reduction of 65%, compared to the control group. The increment reductions reached borderline significance, using the chi-square test.

Child↗
PubMed1977

Preventive practices in schoolchildren in Oppegard, Norway, related to some background factors.

As part of a clinical trial among schoolchildren in a suburban community just outside Oslo, dental preventive behavior was studied by means of mailed questionnaires. In all, 340 mothers, i.e. 95% of the sample, filled out and returned the forms. The results indicate a distinct and improving preventive attitude in the target population. The age of the family was the most influential background variable.

Adolescent↗