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Biomedical subjects

B Ogaard

Publications and source records attributed to B Ogaard.

At least 73 records · Page 4Linked to original sources
PubMed1991

Effect of fluoride mouthrinsing on caries lesion development in shark enamel: an in situ caries model study.

Shark enamel consists of nearly pure fluorapatite and has been shown to demineralize in an in situ caries model. The present study was conducted to investigate whether additional fluoride supplementation in the form of mouthrinsing would inhibit lesion development in shark enamel. The study slabs of shark enamel were mounted in dental appliances. Six individuals wore the appliances while rinsing daily with a neutral 0.2% NaF solution for 4 wk. The specimens were analyzed by means of quantitative microradiography, and the data compared with a previous study using untreated shark enamel and the same participants. It was found that fluoride rinsing did not measurably inhibit enamel demineralization in 4 wk. Scanning electron microradiographs showed that calcium fluoride-like material was not formed on shark enamel after neutral fluoride treatment, supporting a previous study. The present study indicates, therefore, that formation of a calcium fluoride-like material on the enamel surface may be essential for the cariostatic effect of topical agents.

Adolescent↗
PubMed1991

Incidence and prediction of filled teeth from 12 to 18 years of age in a district in Norway.

The present study investigated whether the incidence or prevalence of filled teeth/approximal surfaces at one age could be predictive for the incidence in another period or for the prevalence at the age of 18. The study was conducted in 12-18-yr-olds in Norway. Regression analysis showed that the best prognosis for subsequent incidence of filled teeth/approximal surfaces could be made at the age of 15. By using regression analysis or discriminant analysis it was possible at the age of 15 to predict with high accuracy those who would acquire more fillings than the median at the age of 18. Discriminant analysis with one predictor variable is suggested for clinical use. The variable that discriminated best between above and below median number of new fillings in the period 15-18 yr was untreated lesions in the inner half of the enamel in the approximal surfaces of premolars and molars at the age of 15. From the use of simple prediction tools, it was concluded that individuals at the age of 15 with a low prevalence of filled teeth/filled approximal surfaces and without untreated approximal lesions would be subjected to a low incidence of new fillings until the age of 18.

Adolescent↗
PubMed1991

Formation of fluoride on enamel in vitro after exposure to fluoridated mouthrinses.

The aim of this study was to quantify the formation of alkali-soluble fluoride (loosely bound fluoride such as calcium fluoride-like material and absorbed fluoride) and alkali-insoluble fluoride (firmly bound fluoride or apatitically bound fluoride) when fluoride mouthrinsing solutions were applied on sound human enamel in vitro. Two commercial products containing 0.2% or 0.05% NaF were used during 30 sec, 60 sec, 5 min, and 60 min. The formation of loosely bound fluoride was determined by KOH extraction and visualized by scanning electron microscopy. The firmly bound fluoride was measured by three consecutive acid etchings of the enamel. Even during short periods of application there were deposits on the enamel surface. The amount of deposit increased with time of exposure to the 0.2% NaF solution. Only after treatment for 60 min with 0.05% NaF were significant amounts of alkali-soluble fluoride deposited. No measurable amounts of firmly bound fluoride were observed.

Calcium Fluoride↗
PubMed1991

[Possible limitations in the caries preventive effect of fluorides?].

The cariostatic effect of fluoride at different levels of pH in the plaque fluid is discussed. At the pH level 5.5 to 4.5 the plaque fluid is undersaturated with respect to hydroxyapatite and supersaturated with respect to fluorapatite (3). The hydroxyapatite of the enamel then dissolves. With fluoride present in the liquid phase a fluoridated apatite is precipitated in the surface zone of the lesion. In acidic, old plaque the plaque fluid is very likely undersaturated also with respect to fluorapatite (pH less than 4.5) (11). When the liquid phase is undersaturated with respect to fluorapatite no redeposition of mineral lost can occur. In due time an erosion will develop. It is speculated that one reason for the minor effect of fluoride in some caries active patients and in fissures as well is that the plaque fluid is undersaturated with respect to fluorapatite for extended periods.

Apatites↗
PubMed1991

[Cariological conditions in patients in a psychiatric hospital in Norway].

The caries status was recorded for 107 patients in a Norwegian psychiatric hospital in 1988. The number of edentulous patients was highest among patients older than 50 years (42%). Only two patients below 50 years of age were edentulous (5%). The average DMFT was 21.5 in the age group below 50 years and 26.8 in the age group above 50 years. The percentage number of patients with carious teeth (DT greater than 0) was 42% in those above 50 years and 60% in those below 50 years of age. On average, each patients used nearly 3 medicaments regularly. Most of the medicaments belonged to the antidepressiva and neuroleptica group which give nearly complete xerostomia. It is speculated that the reason for the high caries activity in the hospitalized psychiatric patients is due to irregular eating and oral hygiene habits in combination with complete or partial xerostomia. It is suggested that fluoride therapy (topical and tablets) and professional plaque control would be the most appropriate preventive measures.

Adolescent↗
PubMed1991

[Calcium fluoride or not? That is the question!].

The relative cariostatic effect of fluoride as fluorapatite, calcium fluoride-like material, loosely bound fluoride or KOH-soluble fluoride is debated. The present study was carried out to investigate this further in an intraoral caries model. Pair of premolars extracted for orthodontic reasons were used. Enamel from one tooth of each pair was used as controls (untreated). Two slabs were cut from the enamel of the other contralateral premolar. These slabs were treated with 2% NaF for 24 h. One slab was then treated with 1 mol/L KOH for 24 h to remove all loosely bound fluoride. The slabs treated with 2% NaF and then 1 mol/L KOH would contain the KOH-insoluble fluoride. Those treated with only 2% NaF would, in addition, contain KOH-soluble fluoride. Each slab, control, KOH-insoluble F and KOH-soluble and insoluble F, was mounted on different upper removable appliances. The slabs were covered with orthodontic banding material, allowing space for plaque accumulation. Five individuals wore the appliances in 3 separate 4-week periods. The slabs were analyzed by quantitative microradiography. The average mineral loss (delta Z) was 1680 +/- 1000 vol% z microns in the control teeth, 620 +/- 76 vol% . microns in the KOH-soluble and insoluble F teeth and 2167 +/- 1278 vol% . microns in the KOH-insoluble F teeth. The average lesion depths were 90 +/- 41 microns in the control teeth, 35.3 +/- 5.5 microns in the KOH-soluble F teeth and 88 +/- 35 microns in the KOH-insoluble F teeth. It was concluded that only KOH-soluble fluoride reduced mineral loss and lesion depths significantly compared with the untreated teeth.

Calcium Fluoride↗
PubMed1990

Relative cariostatic effects of KOH-soluble and KOH-insoluble fluoride in situ.

The relative cariostatic effects of fluoride as fluorapatite, CaF2, loosely-bound fluoride, or KOH-soluble fluoride are debated. The present study was carried out to investigate this further in an intra-oral caries model. Pairs of premolars extracted for orthodontic reasons were used. Enamel from one tooth of each pair was used as control (untreated). Two slabs were cut from the enamel of the other contralateral premolar. These slabs were treated with 2% NaF for 24 h. One slab was then treated with 1 mol/L KOH twice for 24 h for removal of all loosely-bound fluoride. The slabs treated with 2% NaF and then with 1 mol/L KOH would contain the KOH-insoluble fluoride. Those treated with only 2% NaF would, in addition, contain KOH-soluble fluoride. Each slab, control, KOH-insoluble F, and KOH-soluble and insoluble F was mounted on different upper removable appliances. The slabs were covered with orthodontic banding material, thus allowing space for plaque accumulation. Five individuals wore the appliance in three separate four-week periods. The slabs were analyzed by quantitative microradiography. The average mineral loss (delta Z) was 1680 +/- 1000 vol% x microns in the control teeth, 620 +/- 76 vol% x microns in the KOH-soluble and -insoluble F teeth, and 2167 +/- 1278 vol% x microns in the KOH-insoluble F teeth. The average lesion depths were 90 +/- 41 microns in the control teeth, 35.3 +/- 5.5 microns in the KOH-soluble F teeth, and 88 +/- 35 microns in the KOH-insoluble F teeth. It was concluded that only KOH-soluble fluoride reduced mineral loss and lesion depths significantly, compared with the untreated teeth.

Calcium Fluoride↗
PubMed1990

Effects of fluoride on caries development and progression in vivo.

The dissolution rate of calcium-fluoride-like material from the enamel surface in vivo appears to be much slower than previously thought. This could be due to adsorption of phosphate ions and/or protein molecules to the surface of the calcium-fluoride-like particles. During cariogenic challenges, the phosphate/protein coating is released, resulting in increased solubility rate of the calcium-fluoride-like material. Due to this mechanism, calcium-fluoride-like material may be a major aspect of the cariostatic mechanism of topically applied fluoride. Topically applied neutral fluoride agents are able to inhibit caries development in enamel but not completely stop lesion development. A fluoride solution at low pH has been found to be more effective in caries model studies than neutral fluoride agents, which might be due to the formation of a larger depot of calcium fluoride. Data from fluoridated areas indicate that the fluoride ion as such has a limited effect on lesion development, and a major mechanism of the cariostatic effect may be reformation of apatite (remineralization). The product of lesion consolidation (a fluoridated apatite) may have a limited effect, since intra-oral caries model studies show that even pure fluorapatite, in the form of shark enamel, demineralizes. In fissures and around orthodontic appliances, conventional fluoride agents appear to have only a small effect.

Calcium Fluoride↗
PubMed1990

[Simple model explaining the caries inhibiting effect of fluoride].

The pH at which enamel dissolves is affected by presence of fluoride in the plaque fluid. It appears that the degree of oral hygiene will also be important because pH can drop so low in old plaque that even solid fluorapatite dissolves. Improved oral hygiene would thus reduce caries in high risk patients even in the presence of fluoride.

Dental Caries↗
PubMed1989

Prevalence of white spot lesions in 19-year-olds: a study on untreated and orthodontically treated persons 5 years after treatment.

In the present study the prevalence of white spot lesions (initial enamel lesions) on the vestibular surfaces was recorded in 19-year-olds subjected to and not subjected to orthodontic treatment. Fifty-one orthodontic patients and 47 untreated subjects were examined. On the average, 5.7 years had elapsed since orthodontic appliances were removed. The median white spot score was significantly higher in the orthodontic group than in the untreated group. The orthodontically treated subjects also had more teeth with white spot lesions than the untreated subjects. The highest prevalence was noted on the first molars in both groups. In the orthodontic group the mandibular canines and premolars and the maxillary lateral incisors were also affected. The present study showed that white spot lesions after orthodontic treatment with fixed appliances may present an esthetic problem, even more than 5 years after treatment.

Adult↗
PubMed1989

Incidence of filled surfaces from 10-18 years of age in an orthodontically treated and untreated group in Norway.

The present study was conducted to examine the incidence and location of filled surfaces from 10-18 years of age in individuals subjected to and not subjected to treatment with fixed orthodontic appliances. Each group comprised 65 individuals. About 5 years had elapsed since the appliances were removed. No statistically significant difference in filled surfaces was found between the groups at age 10 to 18. The incidence in filled surfaces from 10-18 years was 6.34 in the orthodontic group, and 7.22 in the untreated group. The difference was not statistically significant. The distribution of fillings in the dentition in the two groups showed no significant differences. Most of the fillings were recorded in the fissures of the molars. In the first molars most of the fillings in the fissures were already present at the age of 10. It was concluded that in individuals with relatively low caries activity, the present fluoride regimes are sufficient to prevent any excess caries lesion development requiring filling during or after orthodontic therapy.

Adolescent↗
PubMed1989

Influence of glutardialdehyde on dentin demineralization in vitro and in vivo.

In this paper the results are presented on the action of glutardialdehyde (GDA) on the in vitro demineralization of human dentin and on the in vivo demineralization of dentin using the Ogaard orthodontic banding system. The results show that a 2 min application of a 2% GDA solution at pH = 3.6 reduces dentin demineralization in vitro and in vivo substantially. Microradiography shows a percentage reduction of lesion depth and mineral loss in vitro of 20 and 36%, respectively. After 2 wk in vivo demineralization the same percentage reductions are 60 and 44%, respectively. The mechanism of action of GDA on dentin is not certain yet. Presumably the in vitro action is due to surface cross-linking of the dentin matrix causing reduced Ca and phosphate transport out of the dentin. In vivo an additional effect may be a rather short term influence of GDA on plaque or on plaque accumulation. The results of this paper indicate that glutardialdehyde is an interesting agent to consider in the reduction of root caries.

Aldehydes↗
PubMed1989

Differences in functional variables, fillings, and tooth wear in two groups of 19-year-old individuals.

Fifty-one individuals (28 girls and 23 boys) who had received orthodontic treatment were compared with 47 subjects (19 girls and 28 boys) without such treatment as to maximal mandibular mobility, chewing muscle tenderness, morphologic occlusion, occlusal/incisal state, and degree of tooth wear. All were 19 years old. There were no statistically significant differences between the groups except for the number of teeth present and maximal mouth opening, which were both smallest in those who had received treatment. The first finding is evident, extraction of premolars being an accepted mode of orthodontic treatment. The reduced mouth opening capacity was related to an increased number of individuals with four or more palpably tender muscle sites in that group of individuals.

Adult↗
PubMed1989

[Dummy- and finger-sucking habits among 5-year old children. An investigation of frequency and effect on the dentition and occlusion].

Dummy- and finger-sucking habits were investigated among 60 5 year olds, born in 1982. The children were living in Raufoss, a small rural community in eastern part of Norway. Information about the sucking habits was obtained from their parents by means of questionnaires. The position of the teeth and the occlusion were registered by an orthodontist. Total prevalence of sucking habits was 63%. Thirty-seven percent, had used a dummy and 30% had been or were still finger-suckers. Two children had both used a dummy and sucked their fingers. This is a significant lower total prevalence of sucking habits than recorded in recent Swedish and Danish studies (1-8), but comparable with a Swedish study from 1971 (9). Most dummy-suckers had broken their habits at 3-4 years of age, while the finger-suckers were still active at 5 years of age. Finger-sucking had the largest impact on the position of the front teeth. The finger-suckers had significantly larger overjet and smaller overbite, more proclined upper incisors and retroclined lower incisors than dummy-suckers and those without any sucking habit. The only measurable effect of previous dummy-sucking of 5 years of age was a more open position of the lips and a smaller overbite. Otherwise, no significant effect on the occlusion was observed in any of the dummy- or fingersuckers.

Child↗
PubMed1989

[Collaboration between general practitioners and orthodontists].

The orthodontic service in Norway is mainly performed in private practices. However, in Oppland county, in the eastern part of Norway, there are several public orthodontic clinics. Financial support for orthodontic treatment is minimal whether carried out by private or public orthodontists. The public dentist has the main responsibility for diagnosing. The present study was conducted to examine the collaboration between general public dentists and orthodontists in Oppland county. The study was based on telephone interviews with 48 dentists. More than 90% of the dentists claimed that the orthodontic services in their district was sufficient. 81% felt that there was no orthodontic overtreatment. Written contact with the orthodontist was more common than oral communication (telephone). 31% of the dentists had weekly contact with the orthodontist, and 50% had monthly contact with the orthodontist. One third of the dentists expressed a desire for regular meetings with the orthodontist. Nearly two-thirds of the dentists preferred the orthodontist having the responsibility of diagnosing malocclusions. 81% were well satisfied with the treatment results. 63% rarely observed adverse effects of orthodontic treatment. The most common indications for recommending orthodontic treatment were functional disorders and prophylactic measures, and 65% considered the esthetic aspect of a malocclusion less important when referring a patient to an orthodontist. 62% felt that the financial support for orthodontic treatment in Norway today was unsatisfactory. 42% of those interviewed were of the opinion, that orthodontic services should be free, whereas 54% thought that orthodontic services should be only partly subsidized.

Adult↗
PubMed1989

[Continued reduction of incidence of caries among children and young adults in USA].

The article presents data from National Institute of Health on the prevalence of dental caries in 5-17 year olds in 1986-87 in USA. The data were compared with a previous study from 1979-80. Almost 50% of the children had no caries experience in 1986-87 compared with 36% in 1979-80. The DMFS data showed a reduction of about 36%, the mean for 1979-80 and 1986-87 being 4.77 and 3.07, respectively. The survey results showed that decay on the smooth surfaces of teeth, the surfaces that benefit most from fluoride, is disappearing. Today, two-thirds of caries is found on the occlusal surfaces of teeth. In Norway, the percentage of 5-year-olds without caries experience and mean DMFT in 12- and 18-year-olds have been registered since 1984. The American data are therefore not easily comparable with the situation in Norway. However, the mean DMFS values in 18-year-olds is hardly less than 13, whereas the average DMFS value of US 17-year-olds in 1986-87 was 8.04. The NIDR survey did not address the question of what is causing the decline in dental caries. The most likely reason is the widespread use of fluoride and in particular use of fluoride dentifrices. Fluoride dentifrices were introduced on the American marked in the 1950s, and in Norway in 1971. It is speculated that a further decline in dental caries may be expected also in Norway.

Adolescent↗