Biomedical subjects

B Ogaard

Publications and source records attributed to B Ogaard.

At least 37 records · Page 2Linked to original sources

PubMed1996

Dummy-sucking behaviour in 3-year old Norwegian and Swedish children.

Forty 3-year-old dummy-sucking children (22 Swedes and 18 Norwegians) together with one of their parents, were shown a specially prepared videotape for 15 minutes The child had free access to its dummy while watching the video. The dummy-sucking time and sucking reactions to the different film sequences were registered. The presence or absence of a posterior crossbite was recorded as well as the upper and lower intercanine arch widths. Dummy-suckers in these populations have earlier been reported to have different prevalences of posterior crossbite. The prevalence of posterior crossbite was especially high for Swedish girls. The results showed that Norwegian boys used their dummies significantly less, and the Swedish girls had significantly narrower upper dental arches than the other children. Dummy-sucking reactions to frightening, cheerful or boring parts of the video were not significantly different among the children. All the children showed compassion for the film characters, and all the children used the dummy when going to sleep. The study lends support to the hypothesis that dummy-sucking influences arch widths and increases the likelihood for development of a posterior crossbite.

Child Behavior↗

PubMed1996

Microradiography and confocal laser scanning microscopy applied to enamel lesions formed in vivo with and without fluoride varnish treatment.

The aim of the present investigation was to combine 2 techniques suitable for lesion characterization: quantitative microradiography (TMR) and confocal laser scanning microscopy (CLSM) on in vivo induced lesions with and without a fluoride varnish (Duraphat) treatment. Orthodontic bands were attached to premolars to be extracted for orthodontic reasons to induce enamel caries on the buccal surfaces. In the caries development part of the study, 1 tooth of each pair received at the start 1 topical application with the fluoride varnish Duraphat, the contralateral tooth serving as untreated control. All teeth were extracted after 4 weeks. In the caries progression part, the premolars were banded for 4 weeks without any treatment to induce caries, 1 premolar in each pair was then extracted and analyzed. The contralateral tooth received one Duraphat application and was extracted after another 2 weeks. In the caries development part of the study, TMR analysis showed that the Duraphat treatment on sound enamel reduced lesion depth by 48% compared to the untreated control. In the caries progression part, no significant difference was found between the untreated teeth extracted after 4 weeks and the fluoride treated lesions extracted after another 2 weeks. CLSM images agreed well with the TMR measurements. In the fluoride treated lesions, the CLSM images showed more light scattering indicating precipitation of material.

Adolescent↗

PubMed1996

Oral hygiene as a variable in dental caries experience in 14-year-olds exposed to fluoride.

The aim of the study was to examine the relationship between oral hygiene level and caries experience in 14-year-olds using fluoride dentifrices on a regular basis. Oral hygiene expressed as Gingival Bleeding Points (GBP) was recorded in 267 individuals in the county of Lillehammer in Norway. Total caries experience as DMFS and approximal carious lesions in the outer half of the enamel (D1), in the inner half of the enamel (D2), in dentin (D3), and filled approximal surfaces were registered clinically and on standardized bite-wing radiographs. Using multiple regression analysis, oral hygiene level expressed as GBI was the only factor that could account for variation in caries experience (DMFS). Any significant effect of consumption of sweets on caries experience could not be demonstrated with the multivariate analysis. The average percentage of GBP (+/- SD) was 35.7 +/- 10.0%. The individuals were divided into one group with good oral hygiene (GBP < 35.7%) and one group with poor oral hygiene (GBP > or = 35.7%). Significantly fewer carious lesions and filled approximal surfaces were demonstrated in the group with good oral hygiene compared with the group with poor oral hygiene. About 16% of the study population used fluoride tablets or fluoride mouthrinses in addition to a fluoride toothpaste. Only in the good oral hygiene group, additional fluoride resulted in a lower caries experience compared with those using only a fluoride toothpaste. In the group with poor oral hygiene, additional fluoride did not result in lower caries experience. The study thus supported the view that during regular fluoride exposure oral hygiene level is an important variable to explain caries risk.

Adolescent↗

PubMed1996

The prevalence of malocclusion in 13- to 15-year-old children in Nairobi, Kenya.

Data on occlusal features and the need for orthodontic treatment in Kenya is scanty. This study was carried out to determine the prevalence of malocclusion in children in Nairobi, Kenya. Nine hundred and nineteen children aged 13-15 years (468 male, 451 female) were examined. The registration method used was that described by Björk et al. The prevalence of malocclusion was 72%. The predominant anteroposterior relationship of the dental arches was neutral occlusion (93%). Specific malocclusion traits were highest for crowding (19%), rotations (19%), posterior crossbite (10%), maxillary overjet (10%), and frontal open bite (8%). There was no statistically significant difference in the overall prevalence of malocclusion between males and females, but some occlusal traits were significantly higher in males. Although the findings indicate that the present population is not characterized by a substantial difference in the overall prevalence of malocclusion compared with other communities, some traits differed in prevalence from those reported elsewhere.

Adolescent↗

PubMed1995

The effect on the tensile bond strength of orthodontic brackets of titanium tetrafluoride (TiF4) application after acid etching.

Titanium tetrafluoride (TiF4) was applied to acid-etched enamel surfaces to study the effect on surface structure and tensile bond strength of orthodontic brackets. Three groups of 20 premolars each were compared in debonding tests. Group I received a 1% and Group II received a 4% topical TiF4 treatment after acid etching. Group III served as control, that is, no fluoride solution was applied to the enamel after acid etching. Each treatment lasted 60 seconds followed by a thorough rinsing with water for 30 seconds. Brackets were bonded on all teeth with the same procedure. All premolars were then placed in a water bath at 37 degrees C. Ten teeth from each group were debonded after 24 hours, and the remaining teeth were debonded after 6 months. Results indicated that the application of 1% and 4% TiF4 solutions on etched enamel surfaces did not alter the tensile bond strength significantly after 24 hours and 6 months. The scanning electron microscope (SEM) examination of the surface structure demonstrated the presence of extensive reaction products, which covered enamel surfaces and appeared to interfere with etch patterns. It was concluded that the application of TiF4 solutions to etched enamel surfaces before bonding will not have an adverse effect on the tensile strength of orthodontic attachments.

Acid Etching, Dental↗

PubMed1995

Craniofacial structure and soft tissue profile in patients with severe hypodontia.

This study compares craniofacial structure and soft tissue profile in persons with mild hypodontia (group I: 2 to 5 congenitally missing teeth, n = 43), moderate hypodontia (group II: 6 to 9 congenitally missing teeth, n = 15) and severe hypodontia (group III: 10 or more congenitally missing teeth, n = 29) with the structure of persons without hypodontia and with normal occlusion (n = 50). The mean age was about 12 years. In group I, the lower second premolars were the most frequently missing teeth, followed by the upper second premolars and the upper lateral incisors. The relative prevalence of missing second premolars decreased with increasing severity of hypodontia. No consistent pattern could be observed when more than five teeth were missing, indicating a different genetic mechanism than for mild hypodontia. A significant retroclination of the incisors and an increased interincisal angle were observed with increasing severity of hypodontia. This was accompanied by a reduction of lip protrusion, being most evident for the upper lip. Increasing numbers of missing teeth resulted also in a decrease in the mandibular plane angle and a reduction in the anterior lower facial height. Few differences in the skeletal parameters were observed. It was concluded that the typical dentofacial structure in persons with advanced hypodontia may be due to dental and functional compensation rather than to a different growth pattern.

Anodontia↗

PubMed1995

Dentofacial changes in Norwegian and Iowan populations between 6 and 18 years of age.

The purpose of this study was to compare the dentofacial changes in Norwegian and Iowan populations between 6 and 18 years of age. Comparisons of the absolute and incremental changes were made both longitudinally and cross-sectionally. The Norwegian sample consisted of 39 females and 35 males, the Iowa sample consisted of 15 females and 20 males, for whom complete sets of data were available for the period of the study. All subjects had a clinically acceptable occlusion and had not undergone previous orthodontic treatment. Descriptive statistics summarized the changes in 29 parameters. Longitudinal comparison of the growth curves evaluated the curve profiles and curve magnitudes for the two populations for both males and females. The analysis of variance was also used to compare the absolute and incremental changes at ages 6, 9, 12, 15, and 18 years. The study resulted in the following findings: 1. The longitudinal growth profile comparisons of the various dentofacial parameters indicated that the growth trends of the Norwegian and Iowa groups were essentially similar. 2. The comparisons of the growth profiles of the males and females from the two populations also indicated that there were no significant differences between the shape of their growth curves. 3. The comparisons of the curve magnitude, as well as the results of the cross-sectional comparisons, indicated that Norwegians had significantly greater maxillary and mandibular protrusion, and larger proclination of the upper and lower incisors than the Iowans.

Adolescent↗

PubMed1994

The effect of sucking habits, cohort, sex, intercanine arch widths, and breast or bottle feeding on posterior crossbite in Norwegian and Swedish 3-year-old children.

The upper and lower intercanine arch widths and the prevalence of posterior crossbite were registered for 445 3-year-old children with and without a continuing or previous dummy-sucking or finger-sucking habit in different areas in Sweden and Norway. Sami children from northern Norway also took part in the study, as well as 15 medieval skulls with intact deciduous dentitions. Compared with the nonsuckers, an increased prevalence of posterior crossbite was observed for the finger suckers, especially the Swedish girls. Stepwise logistic regression showed that posterior crossbite could be predicted with upper intercanine arch width alone. The finger sucking variable would not improve prediction; neither did other entities such as cohort (residential area), sex, lower intercanine arch width, nor the difference between upper and lower intercanine arch width. High prevalences of posterior crossbite were registered for dummy suckers (pacifiers) especially the Swedish girls (26%). Stepwise logistic regression showed that posterior crossbite in dummy suckers could be predicted with upper and lower intercanine arch width. Stepwise linear regression showed that both arches tended to be narrower in Swedes and girls, and that dummy sucking decreased the upper and increased the lower intercanine arch width. Analyses of covariance revealed that at least 2 years of dummy sucking is necessary to produce a significant effect in the upper jaw and 3 years in the lower jaw.

Bottle Feeding↗

PubMed1994

Regression of white spot enamel lesions. A new optical method for quantitative longitudinal evaluation in vivo.

This article describes a new nondestructive optical method for evaluation of lesion regression in vivo. White spot caries lesions were induced with orthodontic bands in two vital premolars of seven patients. The teeth were banded for 4 weeks with special orthodontic bands that allowed plaque accumulation on the buccal surface. The teeth were left in the dentition for 2 or 4 weeks after debanding. Regular oral hygiene with a nonfluoridated toothpaste was applied during the entire experimental period. The optical scattering coefficient of the banded area was measured before banding and in 1-week intervals thereafter. The scattering coefficient returned to the sound value in an exponential manner, the half-value-time for left teeth being 1.1 week, for right teeth 1.8 weeks, these values being significantly inequal (p = 0.035). At the start of the regression period, the scattering coefficient of left teeth lesions was 2.5 as high as of right teeth lesions, values being inequal with p = 0.09. It is concluded that regression of initial lesions in the presence of saliva is a relatively rapid process. The new optical method may be of clinical importance for quantitative evaluation of enamel lesion regression developed during fixed appliance therapy.

Dental Caries↗

PubMed1994

The effect of titanium tetrafluoride (TiF4) application around orthodontic brackets.

In the present in vivo study, the cariostatic potential of a titanium tetrafluoride (TiF4) solution applied topically around orthodontic brackets was investigated with quantitative microradiography. Also characteristics of the TiF4-treated enamel surface were examined with scanning electron microscopy (SEM). Ten pairs of premolars to be extracted for orthodontic treatment were used in the first part of this study. Brackets were bonded on all teeth with an orthodontic adhesive, and 10 randomly selected premolars served as controls, whereas a similar number were treated with 1% TiF4 around brackets for 60 seconds. After 4 weeks with no topical fluoride supplementation, all teeth were extracted and stored for analysis. Results indicated the 1% TIF4 solution reduced lesion depths and total mineral loss, at the bracket periphery, significantly during the 4-week period. The presence of a surface coating was demonstrated by SEM micrographs. It was concluded that TiF4 may provide a high level performance as a prophylactic agent for orthodontic purposes.

Child↗

PubMed1994

Longitudinal cephalometric standards for Norwegians between the ages of 6 and 18 years.

The purpose of the present study was to develop normative cephalometric standards for Norwegians from 6 to 18 years of age. The subjects in the study included 39 females and 35 males, from the Nittedal growth material. All subjects were Caucasians, and none had undergone orthodontic therapy, all had clinically acceptable normal occlusions and no apparent facial disharmony. Twenty-six measurements were analysed according to the cephalometric analysis used at the University of Oslo Department of Orthodontics. The measurements of posterior facial height, skeletal and soft tissue profiles were also included Comparisons between the dentofacial parameters of females and males at each age were performed using Student's t-test. Significant differences between females and males were present particularly at ages 12 and 15 years of age. There was a significant mean increase in NL/NSL in both sexes from 6 to 15 years of age, but more in females. There was a significant mean decrease in ML/NSL from 6 to 18 years of age, and the angle was significantly smaller in males than in females. The anterior and posterior facial height increased in both sexes from 6 to 18 years of age. The largest increase was in males. Males showed slightly more proclined upper incisors at age 9, 12, and 15 years than females. S-N-A increased more in males than females with the largest increase between 9 and 15 years of age. S-N-B increased in both sexes from 6 to 18 years of age with the largest increase in males.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗

PubMed1994

Effect of a combined chlorhexidine and NaF mouthrinse: an in vivo human caries model study.

Chlorhexidine (CHX) is probably the most widely used and the most potent chemical plaque inhibitory agent, whereas fluoride (F-) is the only truly accepted anticaries agent available at present. As they have discrete mechanisms of action, a combination effect of these agents on human dental caries may exist. The inhibitory effect of CHX on the formation of, and acid production in, plaque may reduce a relatively extreme cariogenic challenge sufficiently for it to be overcome by the local F- concentrations achieved by brushing or rinses. The aim of this study was to evaluate the possible caries inhibitory effect of combining 2.2 mM CHX mouthrinses used twice daily with daily 11.9 mM NaF rinses in an in vivo human caries model using plaque-retaining bands on premolars scheduled for extraction. Nine subjects (a total of 28 teeth) were fitted with the bands for 4 wk. Saliva and plaque samples were collected before and after the study period for bacterial cultures, and the tooth surfaces were analyzed by microradiography after careful tooth extractions. The combination of CHX and F- rinses resulted in enamel mineral loss only slightly higher than that observed in "sound" enamel and clearly less than with F- rinses alone. Both total plaque bacteria and Streptococcus mutans were reduced by CHX rinses, confirming the discrete mechanisms of action.

Adolescent↗

PubMed1994

Closing of dentinal tubules by glutardialdehyde treatment, a scanning electron microscopy study.

The properties of dentin are strongly influenced by the so-called smear layer. This layer is always present on the dentin surface after cutting, drilling, sawing, etc. The smear layer can be removed by various chemical treatments, such as those of acid etching or ethylenediaminetetraacetic acid (EDTA). These treatments remove the smear layer and open the tubules. In this paper, the effect on the smear layer of human dentin of treatment with a 2% glutardialdehyde (GDA) solution at pH 3.5 for 2 min and a 0.5-M EDTA solution at pH 7.4 for 4 min was investigated by scanning electron microscope (SEM). The dentin samples were dried by air or critical-point drying before SEM photography was employed. The number of open dentin tubules was quantified on micrographs of EDTA- and GDA+EDTA-treated dentin. The results show that the GDA treatment fixed part of the smear layer and the superficial dentin surface in such a way that at least 50% of the tubules remained closed after EDTA treatment. By closing the dentinal tubules, the GDA-fixed layer might have a positive effect on dentin hypersensitivity, root caries, and bonding of composite to dentin.

Adolescent↗

PubMed1994

Relationship between oral hygiene and approximal caries in 15-year-old Norwegians.

The objective of the present study was to investigate the relationship between oral hygiene level, as judged from the number of non-bleeding papillae (NBP), and approximal caries development and progression in 14- to 15-year-old Norwegians. NBP, according to Gjermo, were registered in 165 15-year-old Norwegians. Approximal lesions in the outer half (D1) or in the inner half (D2) of the enamel or in dentin (D3) and the total numbers of carious approximal surfaces (D1 + D2 + D3), filled approximal surfaces, and sound approximal surfaces were recorded from bite-wing radiographs from premolars and molars at the age of 14 and 15 years (values expressed as mean +/- SD). The average number of NBP in the whole group was 4.6 +/- 4.5. One group with good oral hygiene (NBP > or = 5, 8.7 +/- 3.3, n = 76) and one group with bad oral hygiene (NBP < 5, 1.2 +/- 1.5, n = 89) were established. Carious approximal surfaces and filled approximal surfaces were significantly higher in the group with few than in the group with many NBP (6.0 +/- 5.9 vs. 1.7 +/- 2.8 and 2.6 +/- 4.3 vs. 0.9 +/- 1.8, respectively). The number of lesions at the age of 15 and progression of lesions from 14 to 15 years were also significantly higher in the group with few NBP. It is concluded than in populations exposed regularly to fluoride, the oral hygiene level may be an important indicator of a high caries risk.

Adolescent↗

PubMed1994

Alkali-soluble fluoride deposition on human enamel exposed to monofluorophosphate-containing toothpastes in vitro.

Enamel specimens from unerupted third molars were treated with the supernatant of monofluorophosphate (MFP)-containing toothpaste slurries in water. Calcium fluoride-like particles were formed on the enamel surface during a 24-h exposure. The globules were soluble in alkali. More particles were seen on enamel treated with a toothpaste containing both MFP and NaF. The experiments showed that the calcium fluoride-like material formed on enamel after treatment with MFP-containing toothpaste probably originates from the free fluoride present in the pastes. The relatively moderate deposition of fluoride may be of clinical significance because the teeth are so frequently exposed to toothpaste. No firmly bound fluoride was found on treatment of enamel with MFP-containing toothpaste.

Adsorption↗

PubMed1993

Tensile bond strength of orthodontic brackets bonded with a fluoride-releasing light-curing adhesive. An in vitro comparative study.

A light-curing, fluoride-releasing adhesive (VP 862, Vivadent, Liechtenstein) for bonding of brackets has been produced for inhibition of white spot lesions during orthodontic treatment. The tensile bond strength after 24 hours and 6 months was investigated and compared with two other light-curing adhesives (Transbond, 3M Corp., Monrovia, Calif., and Heliosit-Orthodontic, Vivadent, Liechtenstein) and two chemical-curing adhesives (Concise, 3M, Monrovia Calif., and Saga Bond, Saga Orthodontics, Kongsvinger, Norway). All adhesives produced adequate strength to be recommended for clinical use. The light-curing adhesives produced slightly lower bond strengths after 24 hours and 6 months, except Transbond, which showed an increase in bond strength in this period approaching the two chemical adhesives.

Adhesives↗

PubMed1993

Topical application of fluorides on teeth. New concepts of mechanisms of interaction.

Prevention of caries in exposed root surfaces constitutes an important clinical problem. It is thus important that clinicians involved with periodontology have an insight into fluoride prophylaxis. The understanding of the cariostatic mechanism of fluoride has improved during recent years. The aim of the present review is to give a short account of the present concept. Calcium fluoride appears to be the only product which is formed on enamel, dentin or cementum during brief topical treatments with fluoride or use of toothpaste containing fluoride. This calcium fluoride is stable in the oral environment; this is contrary to what was believed until recently. The calcium fluoride constitutes a pH-dependent reservoir of fluoride which releases fluoride when pH drops. The practical consequences of this concept is discussed.

Calcium Fluoride↗

PubMed1993

Inhibition of bovine dentin demineralization by a glutardialdehyde pretreatment: an in vitro caries study.

Intact bovine dentin specimens were demineralized in 25 mmol acetic acid buffers (pH 5), with and without a 5-min pretreatment with an acidic 2% glutardialdehyde (GDA) solution. The results demonstrate that GDA inhibits dentin demineralization and that the inhibition depends strongly on the initial calcium and phosphate concentration in the demineralization solution. The observed inhibition increases from about 5% without calcium and phosphate to 38% with a calcium and phosphate concentration initially of 6.4 mmol and 4.1 mmol, respectively. The inhibition can be explained either by a reduction of calcium and phosphate diffusion out of the lesion or by the retention of mineral inhibitors in the dentin.

Animals↗