[Question of the month: presence of spirochetes?].
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Dental Scaling↗
Biomedical subjects
M J Schaeken
Publications and source records attributed to M J Schaeken.
The effect of mouthrinses containing zinc and triclosan on plaque accumulation, development of gingivitis and formation of calculus in a 28-week clinical test.
Experimental mouthrinses containing 0.4% zinc sulphate and 0.15% triclosan, which differed in base formulations were compared to a commercially available non-active control mouthrinse. Following baseline clinical examinations for plaque, gingival bleeding and calculus, the volunteers were provided with a dental prophylaxis and given oral hygiene instruction, stratified into 3 groups and given 1 of 3 mouthrinses. Further clinical assessments were performed after 4, 16 and 28 weeks. Salivary mutans streptococci were also monitored during the study. At 4 weeks, plaque and calculus scores in all groups were low compared to baseline. During the remainder of the study, these improvements were not maintained and both plaque and calculus levels increased in all groups. Plaque was significantly lower (P < 0.05) than in the control at all time points. Calculus was significantly lower (P < 0.05) than in the control at all time points. Calculus was significantly lower at week 28 for experimental mouthrinse group 2. Gingival bleeding also decreased in the initial 4 weeks but increased thereafter in the control group. In contrast, gingival bleeding was significantly (P < 0.05) lower in the two experimental groups than in the control group. No significant changes in mutans streptococci were observed.
Analysis of Variance↗
Effect of chlorhexidine varnish on Actinomyces naeslundii genospecies in plaque from dental fissures.
This study describes the effects of varnish containing 40% chlorhexidine diacetate on Actinomyces naeslundii populations in plaque from human molar fissures. In each of 15 subjects two dental fissures with high levels of mutants streptococci were selected. The experimental treatment consisted of the single application of a small amount of chlorhexidine varnish onto the selected fissures. The varnish was removed 15 min after application. One month after varnish application a significant increase was observed in A. naeslundii counts while the number of mutans streptococci had decreased significantly compared with preexperimental levels. From 85 randomly selected Actinomyces isolates taken from blood agar plates before varnish application, 44% belonged to A. naeslundii genospecies 1 and 56% to A. naeslundii genospecies 2. From 106 isolates taken 1 month after chlorhexidine varnish application, 42% belonged to A. naeslundii genospecies 1 and 58% to A. naeslundii genospecies 2. At baseline 28% of A. naeslundii genospecies 1 strains were catalase-positive, but 1 month after varnish application 4% of the strains were catalase-positive (p < 0.05). It is concluded that chlorhexidine varnish application caused an increase of A. naeslundii in dental plaque, but induced no significant changes in the distribution of the two A. naeslundii genospecies.
Actinomyces↗
Sulfate-reducing bacteria in the periodontal pocket.
This report is the first to describe the occurrence of sulfate-reducing bacteria in the human mouth. Samples of subgingival dental plaque were examined for the presence of sulfate-reducing bacteria. Using enrichment cultures, sulfate-reducing bacteria were detected in 25 (58%) of 43 individuals, and in 39 (48%) of the 82 samples. Pure isolates of sulfate-reducing bacteria, obtained from a limited number of enrichment cultures, belonged to the genera Desulfobacter and Desulfovibrio. These genera are also the predominant sulfate-reducing bacteria in the human large intestine. The sulfate-reducing bacteria use sulfate as terminal electron acceptor to oxidize low-molecular-weight organic compounds, mainly products of microbial fermentation such as acetate, lactate etc. The numbers of sulfate-reducing bacteria in the mouth are assumed to be limited by sulfate. Potential sources of sulfate in the subgingival area include free sulfate in pocket fluid and glycosaminoglycans from periodontal tissues.
Acetates↗
Electrical conductance of fissure enamel in recently erupted molar teeth as related to caries status.
Pit-and-fissure caries lesions contribute greatly to the caries incidence in permanent molar teeth in children. To date, the diagnosis of occlusal caries is still performed mainly by visual inspection, periodically aided by bite-wing radiography. However, in detecting small occlusal carious lesions, these methods perform inadequately, especially in low caries prevalence populations or individuals. The use of electrical conductance measurements (ECMs) has been evaluated to improve the diagnosis of small occlusal carious lesions. The aim of this study was to monitor the electrical conductance of fissure enamel in recently erupted molar teeth and to relate these measurements to the caries status. 50 children aged 5-15 years, having first or second permanent molars that were not exposed to the oral environment for more than 6 months, participated in the study. The diagnostic systems evaluated were visual inspection and ECMs. Following baseline data recording, diagnostic measurements were repeated three times within 18 months. Data were collected at predefined sites in the fissures. 18 months after baseline recording, 179 sites at 60 molar teeth in 27 children were judged to require a sealant based on visual inspection. After removal of carious tissue, two examiners jointly decided on the status of decay as per the criteria: 0 = no caries or caries limited to enamel, and 1 = caries involving dentine. The sensitivity of ECM continued to increase with time after a slight initial dip, whereas the specificity continuously increased after baseline measurements as a result of the decreasing amount of false-positive diagnoses.(ABSTRACT TRUNCATED AT 250 WORDS)
Adolescent↗
Streptococci and actinomyces inhibit regrowth of Streptococcus mutans on gnotobiotic rat molar teeth after chlorhexidine varnish treatment.
Clinical studies suggest that the long-term suppression of mutans streptococci on tooth surfaces after intensive chlorhexidine therapy is mainly due to bacterial interference. Other streptococci and also Actinomyces naeslundii are proposed to inhibit regrowth of mutans streptococci after suppression by the agent. We have tested this hypothesis in gnotobiotic rats associated with Streptococcus mutans alone, or associated with S. mutans and strains of Streptococcus oralis, Streptococcus sanguis, Streptococcus gordonii, Streptococcus mitis biovar I, and A. naeslundii. Left lower jaws in these rats were treated with concentrated chlorhexidine varnish, and the return of S. mutans on the treated jaws monitored. In mono-associated rats, S. mutans regained the level of the untreated right lower jaw in approximately 1 week. In contrast, S. mutans remained suppressed for several weeks in rats multi-associated with other streptococci and actinomyces strains. The suppression was more pronounced in the rats fed on basal diet with little free sugars than in rats fed on a sucrose-containing diet. Counts of other streptococci recovered quickly from the intensive chlorhexidine treatment, but A. naeslundii remained suppressed for at least 1 week. The findings demonstrate the crucial importance of the oral microflora in controlling regrowth of mutans streptococci after chemotherapy.
Actinomyces↗
Lactobacilli, mutants streptococci and dental caries: a longitudinal study in 2-year-old children up to the age of 5 years.
A 3-year cohort study was carried out in 252 pre-school children for early identification of caries-active individuals. During this period information was collected about the acquisition of mutants streptococci and lactobacilli from the age of 2 till 5 years old. At baseline mutants streptococci were detected in 43% of the children while the detection frequency of lactobacilli was low (11.5%). On an individual level, numbers of colony-forming units of mutans streptococci and lactobacilli in plaque and saliva varied largely during the study period. The correlations between the numbers of lactobacilli and mutants streptococci in the saliva of the mother and the saliva and plaque of the child were low and never exceeded r = 0.22. Very low correlations (< r = 0.22) were also found between the numbers of mutans streptococci or lactobacilli and the diet in terms of the number of sugar intakes. Nevertheless, in children older than 2.5 years correlations between the clinical caries score and lactobacilli in saliva (range 0.31-0.62) and mutans streptococci in plaque or saliva (range 0.24-0.46) were highly significant (p < 0.01).
Child, Preschool↗
The effect of mouthrinses containing zinc and triclosan on plaque accumulation and development of gingivitis in a 3-week clinical test.
Experimental mouthrinses containing 0.4% zinc sulphate and 0.15% triclosan were compared with a chlorhexidine and a negative control mouthrinse in a 3-week clinical trial. The zinc/triclosan mouthrinses 1 and 2 differed in their ethanol and humectant contents used to deliver the triclosan. The experimental protocol employed the partial mouth gingivitis design, whereby participants wear a toothshield during toothbrushing. Gingival health at baseline was established by professional cleaning, oral hygiene instruction and effective toothbrushing 3 x per day during a pre-experimental period of 2 weeks. The mouthrinses were subsequently used 2x daily following normal toothbrushing during 3 weeks. The pre-experimental oral hygiene phase very effectively reduced plaque levels and gingival bleeding. During the rinsing period, in the absence of mechanical removal of plaque from the protected teeth, gingival bleeding rose to above the prestudy level in the negative control group. The increments (change from baseline to 21 days) of plaque and bleeding scores for the zinc/triclosan mouthrinse 1 were significantly lower than those in the negative control group. As expected, plaque and gingivitis scores were lowest in the group that rinsed with chlorhexidine. The results extend previous observations on the efficacy of the zinc/triclosan system to maintain gingival health.
Adult↗
Effect of chlorhexidine varnish on streptococci in dental plaque from occlusal fissures.
The treatment of tooth surfaces with chlorhexidine varnish may lead to long-lasting suppression of mutants streptococci in dental plaque. Microbiological observations following varnish treatment suggest that this prolonged suppression might be caused by bacterial interference. To investigate whether physiologically related organisms, such as other Streptococcus species, compete with mutans streptococci in the ecosystem, we have analyzed streptococcal populations on the tooth surface before and after chlorhexidine varnish treatment. Occlusal surfaces with high numbers of mutans streptococci were selected in human volunteers and treated with chlorhexidine varnish. Analyses of sequentially collected plaque samples confirmed that S. oralis-group streptococci returned to baseline levels shortly after the chlorhexidine application, while Actinomyces naeslundii populations reached prestudy or even higher levels only several days after treatment. Mutans streptococci, however, were below the detection level in the 14-day samples, except in 1 individual. The pattern of recolonization by individual Streptococcus species after chlorhexidine application closely resembled that of cleaned enamel surfaces: S. oralis and S. sanguis were primary colonizers while S. gordonii became dominant at a later stage. It is concluded that after intensive chlorhexidine treatment, a normal oral microflora reestablished, characterized by low proportions of mutans streptococci.
Actinomyces↗
[The use of chlorhexidine varnish in the prevention of dental caries].
Dentistery recently has developed a new preventive treatment, that is the suppression of the acid-producing bacteria in dental plaque. The background and application of two chlorine hexidine lacquers, EC40 and Clorzoin are discussed.
Administration, Topical↗
Control of calculus formation by a dentifrice containing calcium lactate.
The aim of this study was to re-investigate the anticalculus effects of calcium lactate. To this end calcium lactate was incorporated into experimental toothpastes. Three groups of 20 human volunteers brushed their teeth at least twice daily with three different toothpastes: (1) one containing calcium lactate, (2) one containing calcium lactate plus sodium lauryl sulphate, and (3) a control toothpaste. Plaque accumulation, gingival bleeding and calculus formation were scored at the beginning and at the end of the 3-month experimental period. After the first clinical examination the dentition was professionally cleaned to remove all dental deposits. The use of the calcium lactate containing toothpastes had no significant effects on plaque accumulation and gingival bleeding. However, calculus scores were significantly reduced in the calcium lactate groups at the end of the experiment. The results confirm and extend previous findings that the topical use of calcium lactate reduces calculus formation by, as yet, unexplained mechanisms.
Adolescent↗
The effect of chlorhexidine and zinc/triclosan mouthrinses on the production of acids in dental plaque.
Chlorhexidine, and zinc in combination with triclosan, are used as anti-plaque agents in the prevention of gingivitis. The multifunctional activity of these compounds against bacterial cells has been proposed to include interference with sugar transport and reduction of glycolysis. In this study the ability of the agents to reduce acid production in dental plaque in vivo has been investigated. Samples of smooth-surface plaque were collected from individuals who had been rinsing for several weeks with (a) chlorhexidine (0.12%, Peridex); a combination of zinc and triclosan in mouthwashes containing (b) high and (c) low concentrations of humectant; or (d) a control mouthwash. Analyses using isotachophoresis showed that resting plaques in the chlorhexidine and zinc/triclosan groups contained less acetate than the control group. Acids were also measured 15 min after a glucose rinse. Compared with the control, the amount of lactate was significantly decreased (45%) in the chlorhexidine group, while lactate reduction (20%) in the zinc/triclosan (high humectant) group was not statistically significant.
Acetates↗
Effect of single and repeated application of chlorhexidine varnish on mutans streptococci in plaque from fissures of premolar and molar teeth.
The aim of this study was to determine the effects of one and two applications of 40% chlorhexidine varnish on the numbers of mutants streptococci in human dental fissure plaques from molar and premolar teeth. Twenty-nine subjects (aged 20-30 years) participated in the study and were randomly assigned to one of three groups. In each subject two fissures with high levels of mutants streptococci were selected. The fissures in group 1 (control group) were treated with placebo varnish containing no chlorhexidine. Fissures in group 2 received a single application of 40% chlorhexidine varnish, whereas fissures in group 3 received an additional chlorhexidine varnish application 1 week after the first application. Fissure plaque samples were taken prior to the first application of chlorhexidine varnish and subsequently 1, 2, and 4 months thereafter. Compared with the fissures in the control group, the suppression of mutans streptococci was significant in plaques from group 2 for up to 2 months and in plaques from group 3 for up to 4 months after application. Mutans streptococci were suppressed more strongly in premolar than in molar teeth and more strongly and for a longer period of time in fissures of premolar teeth treated twice than in fissures of premolars treated once.
Adolescent↗
[Experimental gingivitis].
For the experimental gingivitis study 4 (pre)molar teeth were selected and a splint was made over these teeth. During toothbrushing the splint covered the experimental teeth. After brushing it was removed and the volunteers rinsed with chlorhexidine solution (1.2%) or placebo. The results showed tht chlorhexidine rinsing prevented almost completely the accumulation of plaque and onset of gingivitis. The use of the splint facilitated the compliance considerably.
Chlorhexidine↗
Performance of some diagnostic systems in examinations for small occlusal carious lesions.
The objective of this study was to compare the performance in occlusal caries diagnosis of various available diagnostic systems when applied to the same teeth. The sample investigated consisted of 13 children for whom 4 premolar and 19 molar teeth were judged to require a sealant. The indication was based on the criteria 'fissure discoloration', 'enamel decalcification' and 'absence of dentinal decay'. For predefined locations within these occlusal fissures a diagnosis was obtained by the following diagnostic systems: clinical examination, examination on fiber-optic transillumination (FOTI), fissure discoloration, electrical resistance measurement, radiographic examination and ratings of fissure morphology. Tooth material was removed until no (more) carious enamel or dentin was left. Two dentists then jointly decided on the status of decay for each of the defined locations within the fissure. These ratings served as the 'gold standard' diagnoses. The electrical resistance measurement with a sensitivity of 0.96 and a specificity of 0.71 was the only diagnostic tool with acceptable performance. Radiographic diagnosis was characterized by a moderate sensitivity and specificity. All other diagnostic systems had either very low sensitivities or very low specificities, or both. The positive predictive value of FOTI examination and the negative predictive value of the electrical resistance measurements were very high, irrespective of the prevalence of occlusal dentinal decay.
Adolescent↗
Effects of chlorhexidine-containing gel and varnish on abutment teeth in patients with overdentures.
Previous experiments have shown that daily use of 1% chlorhexidine gel strongly reduced caries development in the abutment teeth under overdentures. The present experiment was designed to determine whether intermittent application of chlorhexidine, either in a varnish or in a gel, might be used as an alternative preventive method, less demanding for the patient. To this end, 31 patients were distributed among four treatment groups, with the number of mutans streptococci in plaque and saliva used as a balancing criterion. The treatments consisted of a single application of 40% chlorhexidine varnish, daily application of 1% chlorhexidine gel for one week, or the corresponding placebo treatments with varnish or gel without chlorhexidine. Patients were re-called for bacteriological and clinical examination at various intervals during an eight-week period following treatment. Chlorhexidine varnish and chlorhexidine gel applications significantly suppressed mutans streptococci on the abutment teeth for four and eight weeks, respectively. In agreement with earlier findings, the numbers of Actinomyces viscosus/naeslundii in plaque were significantly increased after chlorhexidine varnish treatment. The chlorhexidine gel reduced plaque accumulation and gingival bleeding for one week but had no long-lasting effect. The results seem to justify a long-term clinical test of intermittent chlorhexidine applications as an alternative for daily use in patients with overdentures.
Analysis of Variance↗
[Individual risk assessment of caries].
The estimation of individual caries risk factors and the related preventive treatment in the dental practice are discussed. Salivary counts of mutans streptococci and lactobacilli reflect the bacteriological attack (mutans streptococci) and sugar intake (lactobacilli). Caries resistance can be estimated by measurement of the salivary secretion rate and buffer capacity. Treatment of high caries risk patients should be directed against etiological factors. Salivary flow rates and buffer capacity can be stimulated by daily (sugar-free) gum-chewing. For the use of fluoridated toothpaste and sugar intake the dentist is dependent upon the cooperation of the patient. The bacteriological factor in the caries process can be suppressed by application of chlorhexidine varnish.
Anti-Infective Agents, Local↗
[Etiology and prevention of root caries ].
The prevalence of root caries is increasing. An optimal prevention is important because of the difficulties encountered in restoring these lesions. The pathogenesis of root and enamel caries have strong similarities. Consequently, for both the same preventive means should be applied. It is important to adjust the intensity of the preventive measures to the risk level of the individual patient. For high risk patients the use of chlorhexidine is advised.
Anti-Infective Agents↗