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Biomedical subjects

S Twetman

Publications and source records attributed to S Twetman.

At least 19 recordsLinked to original sources
PubMed1992

Caries associated microflora in plaque from orthodontic appliances retained with glass ionomer cement.

The caries associated microflora in dental plaque adjacent to orthodontic brackets retained with a glass ionomer cement (GIC) and a resin based composite was investigated using the split-mouth technique. 3, 8, and 28 days after the onset of the appliances, 48-h-old plaque was sampled. An increasing prevalence of mutans streptococci and lactobacilli in plaque from both retaining materials was found. A tendency to colonize more frequently around the composite retained brackets was noticed for both types of bacteria. The proportion of mutans streptococci in relation to the total viable count was significantly higher in plaque samples from composite retained brackets compared to GIC retained 1 month after onset of treatment. The results suggest that a less caries inducing microflora may develop when GIC is used as luting agent in orthodontic dentistry.

Adolescent↗
PubMed1992

Pit and fissure sealing and mutans streptococci levels in saliva.

The effect of preventive pit and fissure sealants with a resin-based material on the number of salivary mutans streptococci was evaluated in 46 healthy 12-year-old school children (F group) with medium or high counts during a 1-year study period. As controls served 33 children of the same age with the same bacterial levels at baseline (C group) and 55 children with low levels (L group). Caries prevalence and incidence were registered clinically and radiographically. Sealing of all accessible pit and fissures was carried out in the F group with a light-cured Bis-GMA sealant. Bacterial levels at baseline and 3, 6, 12 and 52 weeks after treatment were estimated with a chairside method. The results disclosed a significant (P < 0.05) drop in the number of salivary mutans streptococci in the F and C groups at all sampling occasions compared to baseline. There were however no differences between the groups during the study period. Both the caries prevalence and incidence were significantly (P < 0.05) higher in F and C groups when compared to the L group. The results suggest that preventive pit and fissure sealing with a resin based material does not affect salivary mutans streptococci levels.

Child↗
PubMed1991

Mutans streptococci in saliva and interdental spaces after topical applications of an antibacterial varnish in schoolchildren.

The effect of a chlorhexidine-containing varnish on the levels of mutans streptococci in saliva and in interdental spaces was investigated in 33 15-year-old schoolchildren. Each child was treated with an active (1% chlorhexidine; 1% thymol) and a placebo varnish preparation following the split-mouth technique. The varnishes were applied twice in small amounts into upper interdental areas with a 2-d interval. Mutans streptococci in saliva and interdental plaque was sampled and enumerated during 3 months. The results showed an immediate reduction of the number of interdental mutans streptococci on both test and placebo side after the varnish applications. The levels, however, were significantly lower in the test quadrants compared with the placebo-treated sides after 8, 30 and 90 d. Thus, the findings indicate a slower recolonization in interdental spaces treated with the active preparation. The levels of mutans streptococci in saliva were significantly reduced 1 and 3 months after varnish treatment, suggesting a long-term effect of the antibacterial varnish.

Adolescent↗
PubMed1991

Salivary mutans streptococci and caries prevalence in 8-year-old Swedish schoolchildren.

The aim of this study was to obtain cross-sectional information about the quantitative distribution of salivary mutants streptococci assessed with a clinically applicable microbiological method and the relation to dental caries in young schoolchildren. A total of 355 8-year-old children were examined for the presence and number of mutants streptococci in saliva by a specially prepared strip, the "Strip-mutans" method, cultivated in a selective broth. The strips were first visually examined and grouped by aid of a templet provided by the manufacturer and thereafter transferred to a laboratory for enumeration of colony forming units (CFU) with aid of a stereomicroscope. Caries scores were obtained from the dental records. Mutans streptococci were identified in 70% of all children. 46% were free from the bacterium or harboured low levels (0-10 CFU) while high levels (greater than or equal to 500 CFU) were found only in 6% of the material. Strong positive correlations (p less than 0.001) were found between different levels of mutans streptococci infection and the caries experience in both the primary (dmfs) and the permanent (DMFS) dentition. A statistically significant correlation between the direct examination and the microscopic enumeration was disclosed (r = 0.84). The bacterial culturing technique used in this study proved to be practical and reliable and thus useful in clinical routines of pediatric dentistry.

Child↗
PubMed1990

Mutans streptococci in saliva and dental caries in children living in a high and a low fluoride area.

The aim of this study was to obtain information about the quantitative distribution of salivary mutans streptococci and the relation to dental caries in children with contrasting levels of natural water fluoride. A total of 698 schoolchildren aged 12 yr were selected from areas with high (1.2 ppm) or low (0.1 ppm) fluoride concentration in the drinking water. They were all examined for the presence and number of mutans streptococci in saliva by a specially prepared plastic strip, the "Strip mutans" method, cultivated in a selective broth. Data on the caries experience were obtained from the dental records and from bite-wing radiographs. Mutans streptococci were identified in 82% of all children with no difference between the two areas. The number of mutans streptococci was however significantly (p less than 0.05) lower among the children from the high fluoride area than those from the low fluoride area. Children with no detectable or low levels (0-10 CFU) of mutans streptococci had less caries experience than children with moderate or high levels (11- greater than 500 CFU) in both areas investigated.

Child↗
PubMed1990

Diurnal fluoride concentration in whole saliva in children living in a high- and a low-fluoride area.

Salivary fluoride concentrations were investigated in 12-year-old children living in areas with low (0.1 ppm) or high (1.2 ppm) fluoride concentration in the drinking water. Unstimulated whole saliva was collected from 27 children from the respective areas every 2nd hour for 46 h except during sleep. The mean salivary fluoride concentration was 0.32 +/- 0.013 mumol/l (n = 419) in the low-fluoride (LF) area and 0.87 +/- 0.047 mumol/l (n = 401) in the high-fluoride (HF) area. No significant rhythm could be found for the diurnal variations in the mean or individual salivary fluoride concentrations. However, in the HF area the individual salivary fluoride concentrations fluctuated widely and randomly.

Analysis of Variance↗
PubMed1990

Salivary fluoride concentrations in children with glass ionomer cemented orthodontic appliances.

Salivary fluoride concentrations were determined in 10 children (mean age 12.0 years) undergoing fixed orthodontic therapy. The orthodontic appliances, a minimum of 4 bands and 8 brackets, were cemented with a glass ionomer cement. Unstimulated whole saliva was collected 4 times a day before (baseline value) and at 1, 7, 14 and 28 days after cementation. The samples of saliva were centrifuged and the supernatants were analyzed with a fluoride-sensitive electrode. At baseline, the mean salivary fluoride concentration was 0.85 mumol/l. There was a significant increase during the day after cementation (1.88 mumol/l). After 7, 14 and 28 days, salivary fluoride levels were slightly elevated, but not statistically different from the baseline values. The ingested fluoride dose during the 1st day was estimated to be 0.02 mg. It is concluded that in orthodontic treatment with fixed appliances, a slow release of fluoride from glass ionomer cements could exert a local cariostatic effect on adjacent caries-susceptible enamel.

Adolescent↗
PubMed1990

Cryosurgical treatment of mucocele in children.

Cryosurgery of superficial mucoceles located in the lower lip of eight children is reported. The treatment did not require administration of local anesthetics and was easily performed and well-tolerated even by small children. Healing proceeded uneventfully in all patients. No recurrence during a 1-year follow-up period was observed. Cryosurgery proved to be an effective and essential tool in the management of mucocele in children.

Child↗
PubMed1989

Mutans streptococci and lactobacilli in saliva from children with insulin-dependent diabetes mellitus.

The quantitative distribution of mutans streptococci and lactobacilli in saliva of insulin-dependent diabetic children was compared with a group of healthy children and related to the metabolic control of the disease. The study group, consisting of 94 boys and girls (age 4-19) with type 1 diabetes was matched by sex and age with a non-diabetic control group. Stimulated whole saliva was collected and flow rate, buffer capacity and the levels of mutans streptococci and lactobacilli were analysed in all children. In the diabetic group, total salivary proteins and glucose content of saliva were determined. Data on caries experience were recorded from the dental cards of all children. There were no difference in the distribution or number of mutans streptococci between the groups, but significantly (p less than 0.05) lower levels of lactobacilli were found among the diabetic children. The number of lactobacilli was positively correlated (p less than 0.05) to glucose concentration in saliva. There was no difference in the prevalence of caries between the groups. The present findings suggest that the dietary treatment of young insulin dependent diabetics gives rise to a reduced number of lactobacilli in saliva but does not affect the mutans streptococci.

Adolescent↗
PubMed1989

Effects of the thiazide diuretic bendroflumethiazide on salivary flow rate and composition.

Thiazide diuretics are among the first-line alternatives in the treatment of primary hypertension. The effects of thiazide treatment on salivary production are, however, little studied and the results so far available are not decisive. The aim of the present study was to evaluate and compare salivary flow rate and composition during treatment with the thiazide diuretic bendroflumethiazide in a low dose (2.5 mg o.d.) and placebo. The study was performed with a randomized, double-blind, cross-over design (2 x 2 wk) in 34 healthy volunteers. The treatment periods were separated by a wash-out period of 2 wk. Resting and stimulated whole saliva was sampled three times daily on scheduled days during the treatment periods. Flow rate was assessed for resting saliva, whereas flow rate, pH, buffer capacity, amount of total proteins and concentrations of sodium, potassium, calcium, phosphate and magnesium were measured for stimulated whole saliva. No effect of bendroflumethiazide on the resting salivary flow rate could be detected, while the stimulated flow rate was significantly reduced by about 10% during the thiazide treatment. The total sodium output was significantly decreased by approximately 30%, without any detectable change in total potassium output. All other variables of stimulated whole saliva studied were not different from placebo. It is concluded that treatment with bendroflumethiazide in a low dose significantly reduces the stimulated whole salivary flow rate and total sodium output in healthy volunteers.

Adolescent↗
PubMed1989

Oral mucous membrane lesions in children treated with bone marrow transplantation.

Oral mucous membrane lesions were studied in 54 children below 12 yr of age treated with allogeneic bone marrow transplantation mainly because of hematological malignancies. Sixty-two percent of the children exhibited a wide range of oral side effects during therapy. Lesions observed during the first 2 wk prior to engraftment of the donor marrow were related to the chemo- and radiotherapy given. Oral ulcerations were seen in 34% of the children. Children given methotrexate as graft-versus-host disease (GVHD) prophylaxis exhibited oral ulcerations significantly (P less than 0.05) more often than those given cyclosporin. Oral lesions related to acute GVHD were only observed in two patients. Reactivating herpes simplex virus infection was seen in 35% of the children who were seropositive prior to BMT. An extensive oral candidiasis was observed in 15% of the patients. All six children with a chronic GVHD exhibited changes in the oral mucosa 2-4 yr after transplantation such as erythma of the mucous membranes, tongue atrophy and also lichenoid changes in the buccal mucosa.

Antineoplastic Agents↗
PubMed1988

Increased (L+)-lactic acid production in lysozyme-inactivated suspensions of human dental plaque.

The effect of lysozyme-inactivation on L(+)-lactic acid (LA) production in dental plaque suspensions was evaluated. From 10 children 24-h plaque was collected and lysozyme activity inhibited by addition of goat antiserum to human lysozyme. Acid production was stimulated by addition of glucose. The results showed significantly increased LA levels (50-150%) in lysozyme-inactivated plaque suspensions from 8 of the subjects compared to untreated controls. The increase in acid production activity was not related to plaque lysozyme levels. The findings indicate that the presence of lysozyme may be limiting on acid production in the early dental plaque.

Adolescent↗
PubMed1987

Lysozyme activity and L(+)-lactic acid production in saliva in schoolchildren with high Lactobacillus counts.

Out of 374 schoolchildren, aged 13-15 yr, 42 with high counts of salivary lactobacilli (greater than or equal to 10(5] were selected for this study. Lysozyme activity in saliva and L(+)-lactic acid (LA) production after addition of glucose were determined. The mean values of lysozyme activity and LA concentration were 19.4 micrograms/ml and 1.4 mmol/l respectively. The levels of LA produced without addition of glucose were less than 0.2 mmol/l. The results showed a statistically significant (P less than 0.05) negative correlation between lysozyme activity and the levels of LA produced. The findings of this study suggest that lysozyme may be of importance in limiting acid production in saliva.

Adolescent↗
PubMed1987

Effect of inactivated salivary lysozyme on L(+)-lactic acid production in saliva and in cultures of Streptococcus mutans BHT.

The aim of this study was to evaluate the antimicrobial contribution of human lysozyme in saliva. In one series of experiments, L(+)-lactic acid (LA) production in exponential phase cultures of Streptococcus mutans BHT treated with lysozyme-deficient salivary supernatant was determined. In other experiments, LA concentration was measured in whole saliva samples from 22 school-children where the lysozyme activity had been inhibited by the addition of goat antiserum to human lysozyme (GAsL). LA production in both S. mutants cultures and saliva samples was stimulated by D-glucose addition. The results indicated a time dependent increase (approximately 30%) in LA production in lysozyme-deficient reaction-mixtures compared to untreated controls. The mean LA concentration in lysozyme-inactivated whole saliva samples was significantly higher (p less than 0.01) compared to untreated saliva. However, in 4 out of 22 children the GAsL-treatment did not affect LA production. The individual differences could not be related to salivary secretion rate, lysozyme activity or the number of S. mutans and lactobacilli in saliva. The findings of this study suggest a protective role for lysozyme in limiting acid production in saliva, but individual differences exist.

Enzyme Activation↗
PubMed1985

Scanning electron microscopic study of Streptococcus mutans BHT lysed by lysozyme.

The effects of purified salivary lysozyme (HSL) and hen egg white lysozyme (HEWL) on the surface structure of Streptococcus mutans BHT were studied with the aid of scanning electron microscopy. In parallel experiments bacteriolysis was monitored by liberation of 3H-thymidine incorporated into the bacteria. Control cells maintained their shape and had intact cell walls during the experimental period. Exposure of the cells to HSL (5.0 U/ml) or HEWL (5.0 micrograms/ml) for 3 and 18 h resulted in progressive destruction of cell structure. Some cells exhibited ruptures of the cell walls on top of spherical swellings, predominantly located at the ends of the bacteria. After 18 h the majority were disrupted in the septal area leaving numerous empty cup shaped cell walls in the preparations. The findings of the electron microscopic examination were confirmed in the biochemical assay.

Animals↗
PubMed1979

Lysozyme activity in saliva from children with various degree of gingivitis.

The lysozyme activity was determined in paraffin stimulated whole saliva from 51 randomly selected children. The average age was 6.5 years. The children were divided into four groups according to their degree of gingival inflammation. An agardiffusion method was used with Micrococcus lysodeikticus as indicator of the lysozyme activity. The mean value of the lysozyme activity was determined to 48.4 microgram/ml. In the non-inflamed group the enzyme activity was 8.7 microgram/ml, whereas it was lower, 31.5 microgram/ml, in children with inflamed gingiva. The correlation coefficient (p less than 0.05) suggest that there is a negative relationship between saliva lysozyme and the degree of gingival inflammation. Furthermore this study indicates that lysozyme acts as one of the resistant-factors against gingival inflammation in young individuals.

Child↗