Biomedical subjects

D Birkhed

Publications and source records attributed to D Birkhed.

At least 73 records · Page 4Linked to original sources

PubMed1995

Acid production by human strains of Streptococcus mutans and Streptococcus sobrinus.

Acid production by washed suspensions of human strains of Streptococcus mutans (n = 18) and Streptococcus sobrinus (n = 12) was measured. The strains were isolated from infants and adolescents with varying caries experience. Some of these strains and two laboratory strains (1 S. mutans and 1 S. sobrinus) had been tested in an earlier study for their cariogenicity in hamsters. Further, 3 Streptococcus sanguis strains and 1 S. sobrinus laboratory strain were included. Acid production was determined in repeated titration experiments at a constant pH of 5.5. Higher mean acid production activities (p < 0.05) were obtained by S. sobrinus compared with both S. mutans and S. sanguis. However, large variations among the strains were found both between and within the species. No clear relationship was found between the glycolytic activity of strains and the caries prevalence of the children from whom the strains had been isolated or the caries scores in a hamster model. In conclusion, although both S. mutans and S. sobrinus have aciduric and acidogenic properties, it is difficult to relate the acid production activity of pure cultures in vitro to the caries process in vivo.

Acids↗

PubMed1995

Effect of a modified toothpaste technique on approximal caries in preschool children.

A 3-year, double-blind caries trial was conducted to evaluate the caries-reducing effect of a modified technique to use toothpaste. At the outset, 369 children, 4 years of age, were randomly assigned to four groups. At the end of the study, when the children were 7 years old, 281 (76%) had completed the trial. Two of the groups (test groups, n = 131) were given the following instructions regarding 'toothpaste technique': (1) to spread the paste evenly on the teeth prior to brushing, (2) not to expectorate more than necessary during brushing, (3) to filter the remaining dentifrice foam in the dentition, together with a sip of water, by active cheek movements for 1 min before expectorating, and (4) not to carry out any further water rinsings afterwards, and not to eat or drink for 2 h after brushing. The children in the other two groups (control groups, n = 150) were not given any instruction how to use the dentifrice and how to rinse after the brushing, but were, as the children in the test groups, encouraged to use the test dentifrice and to brush their teeth twice daily. Two commercial fluoride dentifrices (A and B) were compared: one of the test groups and one of the control groups used each product. Approximal carious lesions were scored on bite-wing radiographs at baseline and at the end of the study on the distal surface of the first and on the mesial surface of the second primary molars. No difference in caries increment was found between toothpastes A and B. The children in the two test groups developed a mean of 1.14 new dfs during the 3 years compared to 1.55 in the two control groups (p < 0.05). Thus, the results indicate that the modified toothpaste technique reduced approximal caries in preschool children by an average of 26%.

Analysis of Variance↗

PubMed1995

Dietary habits related to caries development and immigrant status in infants and toddlers living in Sweden.

The purpose of this study was to describe the dietary habits of infants and toddlers living in Sweden with special reference to caries prevalence at 2 and 3 years of age and to immigrant status. The study was designed as a prospective, longitudinal study starting with 671 children aged 1 year. At 3 years, all children were invited to a further examination. A total of 298 individuals, randomly selected from the original group, were also examined at 2 years. The accompanying parent was interviewed about the child's dietary habits. Children with caries at 2 and 3 years of age and immigrant children had, when they were 1 year old, consumed caries-risk products and been given nocturnal meals and sweetened liquid in a feeding bottle more often than caries-free 2- and 3-year-olds and non-immigrant children. Although a great variation in dietary habits was found in infants and toddlers, the use of sugar-containing products is widespread in Sweden even in early childhood.

Bottle Feeding↗

PubMed1994

Effect of a long-term change from a mixed to a lactovegetarian diet on human saliva.

The effects of this long-term dietary change on secretion rate, buffer capacity, concentration of sodium and potassium and amylase activity of stimulated parotid and whole saliva was studied in 20 healthy, normal-weight, non-smoking omnivores. Salivary counts of mutans streptococci and lactobacilli were also made. Dietary surveys were carried out and saliva samples collected before (baseline) and 3, 6 and 12 months after the dietary change as well as 3 yr after the end of the lactovegetarian diet period. The dietary data showed an increase in the consumption of fruits, vegetables and dairy products and a decrease in meat, fish, eggs, sweets and biscuits. These changes led to an increased intake of carbohydrates, fibre and water. After 12 months on the vegetarian diet, the secretion rate, buffer capacity and sodium concentration of whole saliva and the secretion rate of parotid saliva had increased significantly. At the 3-yr follow-up, the buffer capacity and sodium concentration were still elevated, while the secretion rate had almost returned to the baseline values. The potassium content of whole saliva showed a tendency to increase during the vegetarian diet period, but had decreased again at the 3-yr follow-up.

Adult↗

PubMed1994

Oral retention of glucose at pharmacologically reduced salivary flow in man.

The aim was to study the influence of mouthrinses with glucose, at concentrations ranging from 1 to 50%, on oral retention at two different locations in the oral cavity. Salivary secretion was reduced in 10 subjects by injection of methylscopolamine nitrate submucosally. The volunteers were randomly assigned to rinse with 10 ml of either 1%, 10%, or 50% glucose solution for 30 s, after which measurements of glucose concentration and parotid salivary secretion rate were performed during a 10-min period. The results showed higher salivary glucose levels vestibularly than sublingually. The difference in glucose retention between the two locations increased when the salivary flow rate recovered. The relationship between secretion rate and area under the curve for glucose measured sublingually, but not in the vestibule, was bilinear.

Adult↗

PubMed1994

Oral hygiene in relation to caries development and immigrant status in infants and toddlers.

The purpose of this study was to describe oral hygiene factors in infants and toddlers living in Sweden with special reference to caries prevalence at 2 and 3 yr of age and to immigrant status. The study was designed as a prospective, longitudinal study starting with 671 children aged 1 yr. At 3 yr, all the children were invited to a further examination. A total of 298 children, randomly selected from the original group, were also examined at 2 yr. The accompanying parent was interviewed about the child's oral health habits. Children who were free of caries at 3 yr had had their teeth brushed more frequently at 1 and 2 yr of age, had used fluoride (F)-toothpaste more often at 2 yr of age, and had a lower prevalence of visible plaque at 1 and 2 yr of age than children with caries. Immigrant children had had their teeth brushed less frequently, had used less F-toothpaste, and had a higher prevalence of visible plaque at 1 yr of age than nonimmigrant children. Early establishment of good oral hygiene habits and regular use of F-toothpaste seem to be important for achieving good oral health in pre-schoolchildren.

Child, Preschool↗

PubMed1994

Effect of buccal administration of a lactose-containing nitroglycerin tablet (Suscard) on plaque pH.

The aim of this study was to monitor pH in 2-day-old dental plaque after administration of a long-acting, lactose-containing nitroglycerin tablet (Suscard). The tablet was placed under the lip of the maxilla. This was done both in two older subjects suffering from heart problems and in 10 younger, healthy subjects. In the latter group, a sucrose-containing lozenge was used as a control. The influence of a 5-wk period of daily use of Suscard (in the two elderly subjects) and the effect of normal oral hygiene procedures (in the 10 younger subjects) on the pH response was also studied. Plaque pH was measured in situ up to 1 h, at five different approximal sites in the front region of the maxilla by the micro-touch method. The Suscard tablet resulted in a fall in plaque pH in both groups when teeth had not been brushed for 2 days. The lowest pH was recorded at the sites close to where the tablet had been placed. The most attenuated pH drop was found in the two older subjects, who showed a mean minimum pH of 5.7, as compared with 6.2 for the younger subjects. No further increase in the pH fall from Suscard was seen after the 5-wk period in the two patients with heart problems. In the 10 younger healthy subjects, the most pronounced pH decrease was registered after administration of the sucrose-containing lozenge. The pH drop for Suscard was not significant when normal oral hygiene procedures preceded the test.(ABSTRACT TRUNCATED AT 250 WORDS)

Administration, Buccal↗

PubMed1994

Effect of xylitol and sorbitol in chewing-gums on mutans streptococci, plaque pH and mineral loss of enamel.

Seventeen subjects with more than 3 x 10(5) mutans streptococci per millilitre of saliva completed this randomised, cross-over study. Four different chewing-gums, containing: (1) 70% xylitol, (2) 35% xylitol + 35% sorbitol, (3) 17.5% xylitol + 52.5% sorbitol, and (4) 70% sorbitol, were tested. The participants used 12 pieces of each gum per day for 25 days. During the four experimental periods, they wore a removable palatinal plate containing two demineralised enamel samples, and brushed their teeth with a non-fluoridated toothpaste. The results showed that an increased concentration of xylitol in the gum resulted in a lower number of mutans streptococci in both saliva and dental plaque, although the decreases were only significant in the saliva samples (p < 0.01). The pH drop in plaque, measured in vivo after a 1-min mouthrinse with a 10% sorbitol solution, was least pronounced after the 70% xylitol gum and most pronounced after the 70% sorbitol gum period (p < 0.01). No significant differences were found after a mouthrinse with a 10% sucrose solution. All demineralised enamel samples lost mineral during the experimental periods. However, the lesion depth as well as the mineral loss values, assessed microradiographically, did not differ significantly between the four chewing-gums.

Adult↗

PubMed1994

Effect of various post-brushing activities on salivary fluoride concentration after toothbrushing with a sodium fluoride dentifrice.

The study consisted of eight experiments, divided into three series, aimed at investigating the effect on the salivary fluoride (F) concentration of three post-brushing regimes: (1) rinsing once or twice with water, (2) rinsing either with a slurry of the toothpaste foam and water or with an 0.05% NaF solution, or a single NaF mouthrinse with no prior brushing, and (3) chewing and drinking ('eating') for 2 min. Brushing was done with 1.5 g of an 0.32% NaF dentifrice. The concentration of F in whole saliva was determined in 15 subjects at various time points up to 45 min after completing each experimental procedure. Results showed that the initial (0 min post-brushing) F concentration in saliva decreased about 1-2 times after a single, and 4-5 times after a double post-brushing water-rinse, as compared with no rinsing at all (p < 0.001). Brushing followed by a mouthrinse with an 0.05% NaF solution elevated the F concentration more than brushing alone (p < 0.001). Rinsing with the slurry of toothpaste foam and water gave only a somewhat (but not significantly) lower concentration of F in saliva than just rinsing with the 0.05% NaF solution. Eating immediately after brushing reduced the salivary F level about 12-15 times (p < 0.001) compared with brushing alone.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1994

Effect of a 3-year professional flossing program with chlorhexidine gel on approximal caries and cost of treatment in preschool children.

The aim was to evaluate the effect of chlorhexidine gel treatment on the incidence of approximal caries in preschool children. One hundred and seventeen 4-year-olds, divided into two groups, participated: (1) chlorhexidine gel group (n = 59), and (2) placebo gel group (n = 58). Group 1 was treated 4 times a year with a 1% chlorhexdine gel and group 2 with a placebo gel. Approximately 0.7 ml of gel was applied interdentally by means of a flat dental floss. A control group (group 3), which did not receive any flossing or gel treatment, was also included in the study (n = 116). After 3 years, i.e. when the children were 7 years old, the mean incidence of caries on approximal surfaces (defs), including both enamel and dentin lesions, was 2.59 in the chlorhexidine gel, 4.53 in the placebo gel and 4.20 in the control group (group 1 vs. 2 and group 1 vs. 3: p < 0.01). Mean number of approximal fillings at the end of the study, i.e. when the children were 7 years old, was 0.33 in the chlorhexidine gel, 1.04 in the placebo gel and 0.80 in the control group (group 1 vs. 2: p < 0.01; group 1 vs. 3: p < 0.05). The progression of approximal caries lesions, diagnosed on bitewing radiographs from the age of 5 to 7, was slower in the chlorhexidine than in the placebo gel group (the control group was not evaluated in this respect). A cost analysis, based on the total treatment time in minutes, showed a small gain for the flossing program.(ABSTRACT TRUNCATED AT 250 WORDS)

Child↗

PubMed1994

Effect of chlorhexidine treatment followed by stannous fluoride gel application on mutans streptococci in margins of restorations.

The effect of antimicrobial treatment on the numbers of mutans streptococci (MS) in plaque from margins of restorations and in saliva was studied. Nineteen persons with well-restored dentitions and > 0.5 x 10(6) MS per ml saliva were treated with 1% chlorhexidine (CHX) gel in individually designed applicators 5 min/day for 9 days. Ten of the subjects continued the treatment with 0.4% stannous fluoride (SnF2) gel and the remaining 9 with a placebo gel for another 14 days. Plaque samples from margins of selected restorations and stimulated saliva were collected at baseline, after the completion of each gel treatment and then again at regular intervals up to 24 weeks. The CHX gel treatment suppressed MS in the margins of restorations as well as in saliva. Additional treatment with the SnF2 gel prolonged this suppression compared with CHX treatment alone. In the CHX-SnF2 group, the number of MS in margins of amalgam and composite restorations was still significantly lower at the end of the study compared with the baseline. In the CHX placebo group, the margins of amalgam restorations, mainly placed in premolars and molars, were recolonized somewhat faster than the margins of composite restorations in the front teeth.

Adult↗

PubMed1994

Effect of water rinsing after toothbrushing on fluoride ingestion and absorption.

This investigation was done to determine the bioavailability of fluoride (F) after toothbrushing associated with different water rinsing procedures. Eight adult subjects participated in four experiments, conducted with a randomised, crossover design: (A) 2 min brushing with an F dentifrice, followed by three quick (3 x 2 s) rinses, each with 10 ml of water; (B) brushing as in A followed by one long-lasting (1 min) rinse with 5 ml of water combined with the toothpaste-saliva mixture; (C) brushing as in A followed by expectoration but without any water rinse afterwards; and (D) ingestion of the toothpaste as a slurry with 100 ml of de-ionized water. Blood samples were collected before and frequently for 6 h after each experiment and analyzed for F content. The area under the plasma F concentration vs. time curves (AUC) was calculated and the degree of F absorption estimated. AUC values obtained in experiment D were assumed to represent 100% F bioavailability. The plasma values recorded during experiment A were not significantly greater than the baseline values, indicating almost no F absorption when 3 quick water rinses were performed after toothbrushing. The degrees of F absorption after one long-lasting water rinse (B) were 7.6 +/- 4.2% and with no water rinse after toothbrushing (C) 23.8 +/- 13.5%, respectively. The results showed that the degree of F absorption after toothbrushing using an F toothpaste is strongly related to the mode of water rinsing.

Absorption↗

PubMed1994

Effect of frequent consumption of starchy food items on enamel and dentin demineralization and on plaque pH in situ.

The aim of this cross-over study was to determine the cariogenic potential of starchy food items as between-meal snacks. This was done by measuring demineralization of human enamel and dentin as well as the pH of dental plaque in situ. Eight volunteers with complete dentures carried two enamel and two dentin specimens, mounted in the molar regions of their mandibular prostheses. There were three test periods, each lasting for 21 days, followed in a randomized order: (1) consumption of starchy food products, 12-15 times a day, in addition to the normal diet (starch period); (2) consumption of sucrose products, 12-15 times a day, in addition to the normal diet (sucrose period); and (3) no addition of test products to the normal diet (control period). Both the starch and the sucrose diets increased the demineralization of enamel and dentin compared with the control period. However, only the sucrose period resulted in significant demineralization of dentin compared with the control period. The plaque pH, followed during 60 min after a one-minute mouthrinse with 10% sucrose, was lower at all time points after both the starch and the sucrose periods compared with the control period.

Aged↗

PubMed1994

Microorganisms on toothbrushes at day-care centers.

The microflora on 44 toothbrushes at 4 day-care centers in the city of Göteborg have been investigated as a presumptive risk factor for transmission of microorganisms by children. Non-supervised toothbrushing without the use of toothpaste was performed at the day-care centers twice a day. Streptococci, predominantly S. salivarius, S. sanguis, and S. mitis, were the most frequently recorded group of microorganisms and generally constituted the greatest part of the flora (on average, 50%). Beta-hemolytic streptococci were not found in any sample. Haemophilus species were noted in 82% of the samples. H. parainfluenzae being the most frequent, and H. influenzae being identified in only one sample. Anaerobes constituted on average a third of the microflora. Staphylococci were identified in 86% of the samples, S. epidermidis dominating. Fungi including molds were found in 50% of the samples, and from one day-care center large numbers of enteric organisms were identified. Thus this study shows that unsupervised toothbrushing at day-care centers can be questioned, more from a general hygienic point of view than from the risk of transmitting serious pathogens.

Bacteria↗

PubMed1994

Cariologic aspects of xylitol and its use in chewing gum: a review.

Several studies indicate that xylitol is not metabolized to acids either in pure cultures of oral microorganisms in vitro or in dental plaque in vivo. Chronic consumption of xylitol-sweetened chewing gum resulted in reduction of dental plaque, suppression of mutans streptococci, and reduced adhesiveness of plaque. So far, four field studies with regimens including chewing gum and other xylitol-containing products and four clinical trials have been carried out. All of the latter studies showed that a daily intake of two to three pieces of xylitol gum resulted in a defined reduction of caries. There are indications that regular and prolonged use of xylitol chewing gum may have a caries-preventive effect.

Bacteria↗

PubMed1994

In vitro and in vivo studies of an NaF impregnated toothpick.

Fluoridated toothpicks (John O. Butler Co.), containing an average of 0.80 mg F as NaF, demonstrated a quick F release in vitro after 1 min immersion in distilled water (0.13 mg; 16%). Continued F release was found after 5 (0.22 mg; 28%) and 60 min (0.35 mg; 44%) and 24 hr (0.55 mg; 69%). In addition, F concentrations were measured in whole saliva of 10 adults before and after 1 min use of an F toothpick and after sucking on an 0.25 mg F tablet (Fludent). Baseline F concentrations of about 1 microM/L increased to 35 microM/L after using the toothpick. In comparison, the F tablet gave a mean salivary F concentration of 71 microM/L. The F levels in saliva after 1 hr were for the F toothpick 3 microM/L and for the F tablet 8 microM/L. Thus, F impregnated toothpick seems to be an interesting vehicle for F release in the oral cavity and merits further studies from a cariostatic point of view.

Adult↗

PubMed1993

Salivary antimicrobial proteins in patients with Crohn's disease.

The aim was to study the level of salivary proteins with antimicrobial properties in persons with Crohn's disease. Twenty-five patients were recruited, 13 with ongoing symptoms (acute group) and 12 free of clinical signs of the disease at the time of the investigation (nonacute group). A control group matched to the nonacute group was also included in the study. Unstimulated and stimulated whole saliva samples were collected, and the secretion rates estimated. Unstimulated saliva was analyzed for concentrations of total protein, peroxidase, thiocyanate, slgA, lactoferrin, lysozyme, and for specific bacteria aggregation ability. Numbers of mutans streptococci and lactobacilli in saliva were determined, and dental caries status was examined. No differences were found among the groups regarding salivary flow rate, total protein, or any of the antimicrobial proteins. However, three patients with Crohn's disease had no detectable slgA in saliva compared with none in the control group. The lactobacillus count and the number of decayed tooth surfaces were higher in the nonacute group than in the control group.

Adult↗

PubMed1993

Fluoride release in vitro from various glass ionomer cements and resin composites after exposure to NaF solutions.

The release of fluoride from 1) discs made from five glass ionomer cements and two composites, and 2) the same discs after exposure to different NaF solutions, were studied. The specimens were placed in distilled water for 10 wk. After 24 h and then once a week, the specimens were transferred to fresh distilled water. After 5 wk, the specimens were divided into four groups and exposed to 0, 0.02, 0.2 and 2% NaF solutions for 5 min. The fluoride release was highest during the first week after preparation, after which it decreased sharply and then more slowly. The amount of fluoride released was ordered: liner/base > restorative glass ionomer > composites. The composites released significantly less fluoride than the glass ionomer cements. After exposure to NaF, the fluoride release was significantly higher for the silver cermet material than for the other glass ionomers tested. From a clinical point of view, the results from this study imply that glass ionomer restorations may act as intraoral devices for the controlled slow release of fluoride at sites at risk for recurrent caries.

Acrylic Resins↗