Biomedical subjects

B Ogaard

Publications and source records attributed to B Ogaard.

At least 55 records · Page 3Linked to original sources

PubMed1993

Effects of oral rinsing with triclosan and sodium lauryl sulfate on dental plaque formation: a pilot study.

Mouthwashes containing 0.3% or 0.15% triclosan in combination with 1.5% sodium lauryl sulfate (SLS) produced a significant reduction in plaque formation in a test panel of 11 students who refrained from oral hygiene during the test periods, during which they rinsed twice daily with different mouthwashes. Pl.I. was evaluated after each test period. A mouthwash containing only 1.5% SLS inhibited plaque to almost the same degree. In both cases, the major effect was on the buccal/lingual surfaces, where score 2 was changed to score 0. Addition of triclosan appeared to reduce the untoward side-effects of mouth-washes containing SLS alone (i.e. desquamation and a burning sensation in the mouth).

Adult↗

PubMed1993

Hypodontia in 9-year-old Norwegians related to need of orthodontic treatment.

The present study reports on the prevalence of hypodontia in a Norwegian population and classifies children with hypodontia according to need of orthodontic treatment. Orthopantomograms of 1953 children (960 girls and 993 boys) at the age of 9 were available for examination. Of the boys registered with hypodontia of second premolars at the age of 9, 11.3% showed late mineralization between the ages of 9 and 12. Only 2.9% of the girls showed late mineralization. The corrected prevalence of hypodontia, excluding third molars, in the girls was 7.2%, in the boys 5.8%, and in both sexes combined 6.5%, the difference between sexes not being statistically significant. Of the children with hypodontia, 86.6% lacked only one or two permanent teeth. The most frequently missing teeth were the mandibular second premolars, the maxillary second premolars, and the maxillary lateral incisors, in that order. Classification of children with hypodontia according to need of orthodontic treatment showed that about two-thirds had hypodontia only of single posterior teeth with a moderate need of treatment. About one-third had hypodontia involving anterior teeth, and only 3.1% had hypodontia of two or more teeth in the same quadrant with a great need of treatment.

Anodontia↗

PubMed1993

Rearing of Swedish, Norwegian, and Norwegian Sami children.

A total of 362 3-yr-old Swedish, Norwegian, and Norwegian Sami (Lapp) children were examined, and their parents were asked about their children's present and previous sucking habits and how long they had been breast-fed and bottle-fed. They were also asked what the children's age was when porridge or puréed food or food with a soft chewing resistance was introduced, and when more ordinary foods such as well-diced meat and potatoes were introduced. The study revealed that breast-feeding has increased greatly both in prevalence and in duration in Sweden during the last decades. Despite this, Swedish children were breast-fed for a significantly shorter time than Norwegian children. The longest breast-feeding times were noted for Sami children. Swedish children were bottle-fed two to three times longer than Norwegian children. Sucking habits were correlated to breast-feeding only for Sami children.

Bottle Feeding↗

PubMed1993

Fluoride acquisition on and in fluorotic human enamel after topical application in vitro.

The uptake of alkali soluble and alkali insoluble fluoride on and in fluorotic enamel was investigated in vitro. Teeth from Kenya, assigned score 3 in accordance with Thylstrup-Fejerskov's fluorosis index, were used. The enamel was treated with either a neutral 2% NaF solution, a 0.2% NaF solution (pH 5.5), or the supernatant from a 0.1% NaF-containing toothpaste (pH 7). The treatment time was 1 h. The reaction product formed on the enamel was analyzed by KOH extraction and acid etching. Significantly higher amounts of alkali soluble fluoride were formed on the enamel from the 2% and 0.2% NaF solutions, as compared with the control. There was also a significant increase in the firmly bound fluoride after treatment with the neutral 2% NaF solution.

Analysis of Variance↗

PubMed1993

The effect of fluoride application on fluoride release and the antibacterial action of glass ionomers.

The aim of this study was to investigate whether the release of fluoride and the antimicrobial effect of freshly mixed glass ionomers could be prolonged by application of fluoride on aged material. Test slabs of freshly mixed and aged (14 d in water) conventional and silver glass ionomer (Ketac-Fil and Ketac-Silver, Espe, Seefeld, Germany) and composite (Silux Plus, 3M, St. Paul, MN) were fitted into the bottom of a test tube. A layer of S. mutans Ingbritt cells was centrifuged onto the test slabs, and the samples were incubated for 20 h in 1.7% sucrose solution. After the incubation, pH, F, and Ca contents of the fluid phase, and F, Mg, P, and K contents of the cells were determined. The aged glass-ionomer samples were then covered with toothpaste (0.1% F) or with fluoride gel (1.25% F), and the composite samples with fluoride gel. After being thoroughly rinsed, S. mutans cells were incubated on the samples as above. The pH fall was significantly inhibited by freshly mixed glass ionomers, and there were changes in cellular cation and phosphorus contents. Large amounts of fluoride were found in the fluid and cells. For old glass ionomers, no inhibitory effect on pH fall could be seen. Fluoride release had decreased to a low level.(ABSTRACT TRUNCATED AT 250 WORDS)

Analysis of Variance↗

PubMed1993

Dental caries and fluorides in relation to fixed orthodontic treatment: a review.

This paper reviews the cariological aspects of fixed orthodontic treatment and discusses the role played by topical fluorides. During fixed orthodontic treatment, carious lesions may occur in the form of white spots. These may constitute an aesthetic problem. The clinical management of white spot lesions remains unresolved. In order to prevent development of these lesions, the use of topical fluorides is advocated. The need for patient co-operation in the use of self-administered topical fluorides is critical. To reduce this critical need, the use of fluoride-releasing orthodontic cements is recommended. The literature suggests that calcium fluoride, which is the major reaction product on enamel during topical fluoride application, plays an important role in the cariostatic mechanism.

Dental Bonding↗

PubMed1992

Cariostatic effect and fluoride release from a visible light-curing adhesive for bonding of orthodontic brackets.

This study was designed to investigate the cariostatic potential in vivo of a visible light-curing adhesive for the bonding of orthodontic brackets. The fluoride release of the adhesive in water and saliva was also measured. Ten orthodontic patients with premolars to be extracted participated. One bracket with Heliosit-Orthodontic (no fluoride) was positioned on the buccal surface of one premolar (control), and another bracket with Orthodontic cement VP 862 (containing fluoride) was positioned on the experimental contralateral premolar. The adhesives were cured with a Heliolux II lamp, and the teeth were extracted after 4 weeks. The patients used a fluoride toothpaste during the experiment. The mineral content of the enamel adjacent to the brackets was determined by quantitative microradiography. The fluoride release from disk-shaped plates of the fluoride adhesive was measured in water for a 6-month period and in human saliva for 24 hours. The fluoride adhesive reduced lesion depths by about 48% than the nonfluoride adhesive (P less than 0.05, t test). The largest release of fluoride from the plates in water was observable within the first week. However, a significant amount of fluoride was still released after 6 months. The fluoride release in saliva was significantly lower in human saliva at pH 7 than in water (P less than 0.01, t test). When salivary pH was lowered to 4, to mimic a cariogenic challenge, the amount of fluoride released increased up to the value measured in water. It was concluded that the regular use of fluoride toothpastes is insufficient to inhibit lesion development around orthodontic brackets.(ABSTRACT TRUNCATED AT 250 WORDS)

Adhesives↗

PubMed1992

Tensile strength of orthodontic brackets bonded directly to fluorotic and nonfluorotic teeth: an in vitro comparative study.

Information related to bonding of orthodontic brackets to fluorotic teeth is scanty. The purpose of this study was to compare, in vitro, the tensile bond strength and the bond failure site of brackets bonded directly to fluorotic and nonfluorotic teeth. The etching patterns were also evaluated. The study involved 26 teeth classified as score 3 and 4, and 26 as score 0 with the Thylstrup and Fejerskov's (TF) fluorosis index. In addition to the clinical classification, difference in the concentration of fluoride in the teeth was verified by acid etching. Brackets were bonded with a composite resin after etching the enamel surface with 40% phosphoric acid for 60 seconds. Tensile bond strength was determined with an Instron testing machine. The bond failure site was assessed by the percentage of residue cement on the tooth surface after debonding and the etching pattern by SEM. The mean concentration of fluoride was 2888.5 ppm (SD 1081.7) in the fluorotic teeth and 1227.1 ppm (SD 526.3) in the nonfluorotic teeth. The mean bond strength was 7.8 N/mm2 (SD 1.47) for the fluorotic teeth and 8.6 N/mm2 (SD 2.19) for the nonfluorotic teeth. The difference between the means for bond strength was not statistically significant (p greater than 0.05). Bond failure site was primarily at the bracket-adhesive interface. The mean percentage of adhesive on the enamel surface after debonding was 70% (SD 25.90) for the fluorotic teeth and 75% (SD 24.66) for nonfluorotic teeth. The difference in the means was not statistically significant (p greater than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Acid Etching, Dental↗

PubMed1992

Sex differences in signs and symptoms from masticatory and other muscles in 19-year-old individuals.

Pain and tenderness of masticatory muscles are often related to muscle tenderness elsewhere in the body. It has been shown that women are more prone to musculoskeletal disorders than men. We sought to determine whether sex differences of muscular symptoms were established by the age of 19. The subjects comprised 51 boys and girls who received a questionnaire regarding the function of their masticatory system, frequency of headache, and neck, shoulder and low back pain. Their masticatory system was examined, and neck and shoulders were palpated. For all variables in the questionnaire girls reported symptoms more often than the boys. Of the subjects 50% had tender chewing muscles upon palpation. Again the girls had the most. There was good correlation between reports of pain in one area as compared to others. The number of clinically tender neck and shoulder muscles correlated with the number of tender masticatory muscles. It was concluded that girls presented more muscular symptoms than boys.

Adult↗

PubMed1992

Dummy- and finger-sucking habits in young Swedish and Norwegian children.

The prevalence of dummy- and finger-sucking habits in 3-yr-old children was registered in four different areas of Sweden and Norway. In Norway 245 children were examined and in Sweden 171 children. The Swedish children were more prone to develop a dummy-sucking habit as well as to prolong it. About 10-19% of the children in the different groups become finger-suckers. Very few of these finger-suckers had stopped sucking at 3 yr of age. The highest rate of non-suckers was found among the children from Karasjok/Kautokeino in northern Norway, who were mainly of Lappish origin.

Age Factors↗

PubMed1992

Acquisition of alkali-soluble fluoride by enamel through treatment with NaF-containing toothpastes in vitro.

The first aim of the present study was to examine if alkali-soluble fluoride (calcium fluoride-like material and adsorbed fluoride) forms when a NaF-containing toothpaste is applied on human enamel surface in vitro. The centrifuged supernatants of toothpastes dissolved in distilled water were used and four different commercial NaF-containing toothpastes were tested. The second aim was to investigate if pyrophosphate would interfere with the deposition of alkali soluble fluoride. The formation of alkali-soluble fluoride was determined by chemical analysis and visualized by scanning electron microscopy (SEM). It was ascertained that all tested toothpastes contained free fluoride according to the manufacturers' specifications. It was shown that they promoted deposition of alkali soluble fluoride on the enamel surface. The amount of deposited material increased with the time of exposure. The clinical effect of a NaF-containing toothpaste may thus well depend on an initial formation of alkali-soluble fluoride. Fluoride from this reservoir may adsorb onto the enamel crystals and inhibit further demineralization or increase the rate of remineralization during cariogenic challenges. It was also demonstrated that pyrophosphate did not interfere with the deposition of alkali soluble fluoride.

Adsorption↗

PubMed1992

Uptake of KOH-soluble and KOH-insoluble fluoride in sound human enamel after topical application of a fluoride varnish (Duraphat) or a neutral 2% NaF solution in vitro.

The uptake of alkali-soluble fluoride (calcium fluoride-like material and adsorbed fluoride) and alkali-insoluble fluoride (apatitically bound fluoride) on sound human enamel from treatment with Duraphat or a neutral 2% NaF solution was investigated in vitro. Blocks from impacted third molars were used. More fluoride was deposited on the enamel from the neutral 2% NaF solution than from the Duraphat treatment. All the fluoride could be dissolved in alkali. Globules of calcium fluoride-like material were demonstrated by scanning electron microscopy. Chemical analysis showed no measurable increase in the apatitically bound fluoride (alkali-insoluble fluoride) after brief exposures. Duraphat-treated samples submerged in water after the exposure lost only about 50% of the deposited fluoride, whereas samples treated with 2% NaF are known to lose all their fluoride under similar circumstances, a condition which may be related to the favorable clinical effect of Duraphat.

Acid Etching, Dental↗

PubMed1992

Rate and mechanism of enamel demineralization in situ.

In this paper, data are presented on the in situ demineralization of human enamel as a function of the demineralization period. To quantify the mineral loss parameters versus time, it is important to obtain information on the kinetics, and thus on the mechanism of dental caries. The results show that for in situ enamel demineralization, the lesion depth as well as the mineral loss parameter both vary linearly with the demineralization time. This is in contrast to in vitro lesion formation where the third power, or the square power of the lesion depth is linearly related to the demineralization time. In in situ demineralization, the rate-determining step of the demineralization process is the inhibitor-controlled dissolution process at the enamel crystallite surfaces, while the inhibitor content (F-, proteins etc.) in the lesion originating from the plaque, saliva and enamel is high. Furthermore, the study indicates that in in situ demineralization, interprismatic mineral loss is very important.

Dental Enamel↗

PubMed1992

The in vivo orthodontic banding model for vital teeth and the in situ orthodontic banding model for hard-tissue slabs.

This paper presents the orthodontic banding model for vital teeth and the orthodontic in situ model for slabs of enamel, root surface, dentin, or other mineralized tissues such as shark enamel. The model for vital teeth is an in vivo model, since a crevice for plaque accumulation is created behind orthodontic bands on the buccal enamel surfaces of teeth in situ. Visible white-spot lesions are usually seen after a four-week banding period in the absence of fluoride. The microbiological flora developed behind the bands shows a similarity to that of natural caries. Microradiographic data show that the initial lesion is a softening of the enamel surface. Later, a subsurface lesion develops. A modification of the model has been developed for the use of slabs of mineralized tissues. In this model, slabs are mounted on a removable appliance. The slabs are covered with orthodontic banding material for plaque accumulation. Lesion development in enamel in the two model systems is almost identical. The benefit of the in vivo model is that caries development can be studied on vital teeth in young individuals. The model is independent of the patient's cooperation. No special diet is required, e.g., no sucrose rinsing. In the in situ model, slabs could be examined after one study period and then replaced for another period.

Dental Caries↗

PubMed1992

Intra-oral models: comparison of in situ substrates.

Numerous intra-oral caries models have been designed for clinical and mechanistic purposes. Several factors--such as human vs. bovine enamel, sound vs. demineralized tissues, lesion type, dentin vs. enamel, the severity of the cariogenic challenge, and the microflora--may influence the reactivity of the hard tissue and hence lesion development and progression. Some models use unextracted teeth and are true in vivo models, whereas in situ models are based on hard-tissue substrates in the form of slabs or sections. Models producing a moderate cariogenic challenge usually show a fluoride dose response. However, caries is increasingly becoming a problem limited to some high-risk patients and to lesions located to areas where severe challenges exist (e.g., fissures and pits). There is thus need for models that could mimic such situations. One of the requirements for intra-oral models producing severe cariogenic challenge conditions should probably be that it should be able to demineralize fluorapatite. A challenge for future caries research is to develop agents that have a better clinical effect in fissures and pits than those presently available. Because, in the past, much emphasis has been placed on remineralization of artificial lesions, more research on the demineralization process should be performed in the future, since this may give improved clinical effects. Ideally, an intra-oral caries model should take into account as many of the natural oral conditions as possible and minimize the degree of artificiality.

Animals↗

PubMed1991

Tensile bond force of glass ionomer cements in direct bonding of orthodontic brackets: an in vitro comparative study.

Tensile bond force of three glass ionomers was evaluated in vitro. Ketac-Cem and Aqua-Cem, two conventional cements, and light-cured Vitrabond were used in this study. The results were then compared with the values obtained for a composite resin (Concise) by means of the Mann-Whitney two-sample rank test adjusted for ties. The composite resin had a significantly higher bond force (152.5 N) than any of the other adhesives (5.5 to 27.53 N) used. Tensile bond strength was also calculated and the failure bond site investigated on the enamel surface was evaluated. The composite resin and the two conventional glass ionomers used had high cement percentages (86% to 62%) adhering to the enamel surface. Cement remaining on enamel was lower (20%) for the light-cured glass ionomer. It was concluded that the in vitro bond force of Vitrabond might be adequate for orthodontic bracket bonding.

Acrylic Resins↗

PubMed1991

An in vivo study on the merits of two glass ionomers for the cementation of orthodontic bands.

The purpose of this study was to investigate the cariostatic effect of two glass ionomer cements on in vivo demineralization of partly uncovered enamel beneath orthodontic bands. A 4-week clinical trial was conducted on a group of five patients with nine pairs of premolars to be extracted for orthodontic purposes. Specially designed orthodontic bands were cemented with either Ketac-Cem (K-C) or Aqua-Cem (A-C). A local cariogenic milieu was created between the buccal surface of the premolars and the inner surface of the bands to secure plaque accumulation. The mineral content of the teeth was quantified by microradiography. The data were compared with data from a previous study of patients in the same age group with bands that had been cemented with a non-F cement. After comparison with the non-F group, the lesion depth (ld) was reduced by 63% for K-C and by 55% for A-C. This reduction was statistically significant at the 2.5% level (t test). The total mineral loss in teeth cemented with glass ionomer cements (delta Z) was reduced, in comparison with the loss in teeth cemented with non-F cement, by 49% with K-C and by 27% with A-C. The differences were statistically significant only for the K-C group (t test, p less than 0.025). There were no significant differences between the two glass ionomer cements with respect to either lesion depth or total mineral loss values (paired t test; p greater than 0.05). This investigation shows that fluoride released from glass ionomer cements contributes substantially to demineralization "reduction." However, these cements do not provide complete caries protection in sites where access is difficult.

Acrylic Resins↗

PubMed1991

Availability of fluoride from glass-ionomer luting cements in human saliva.

Fluoride availability from two glass-ionomer luting agents, Ketac-Cement and Aqua-Cement, was monitored after a 1-h treatment in distilled water at pH 7. The recorded results were then compared to the ones obtained from those same cements, after 1 h, in saliva, in water pretreated with saliva (pH 7 and 4.5), and in albumen and phosphate buffer solutions (pH 7). The Mann-Whitney two-sample rank test was utilized in order to identify the differences. The presence of proteins and phosphate reduced fluoride availability. A reduction in the pH from 7 to 4.5 resulted in an increased rate of fluoride release, in water, from glass-ionomers pretreated with saliva. The present study indicates that fluoride availability from glass-ionomers, in vivo, is pH controlled. The rate controlling factors appear to be phosphate and proteins.

Acrylic Resins↗