Streptococcus mutans, lactobacilli and Streptococcus sanguis in plaque from abutment teeth of cemented and of loose retainers

Periodontal and microbiologic evaluation of 2 methods of archwire ligation: ligature wires and elastomeric rings

INTRODUCTION

Prophylactic programs to prevent dental biofilm accumulation must be implemented to minimize the risk for periodontal diseases in orthodontic patients. Therefore, we assessed the possible periodontal and microbiologic changes resulting from the use of 2 methods of orthodontic archwire ligation: elastomeric rings and steel ligatures.

METHODS

The following parameters were measured: plaque index, gingival bleeding index, probing depth, and biofilm samples from the maxillary second premolars and the mandibular lateral incisors were evaluated in 14 subjects without clinical signs of gingival inflammation before orthodontic appliance placement and after 6 months of treatment. Each orthodontic arch was fixed with elastomeric rings on 1 side of the midline, and steel ligatures were used on the opposite side. Polymerase chain reaction analysis was used to detect Porphyromonas gingivalis, Tannerella forsythia, Actinobacillus actinomycetemcomitans, Prevotella intermedia, and P nigrescens.

RESULTS

The elastomeric rings were associated with a higher score for plaque index and bleeding than steel ligatures, as well as many positive sites of T forsythia and P nigrescens (P <0.05).

CONCLUSIONS

Elastomeric rings favored these 2 periodontopathogens and harmed gingival conditions.

Microbiota of Exposed Root Surfaces After Fluoride, Chlorhexidine, and Periodontal Maintenance Therapy: A 3-Year Evaluation

BACKGROUND

Fluoride and chlorhexidine (CHX) are state-of-the-art preventive measures for remineralizing teeth and for preventing plaque accumulation. The aim of this study was to examine the effects of fluoride and CHX varnishes on root caries and microbiota located on root surfaces.

METHODS

Thirty-three patients from a periodontal maintenance program, having at least one tooth with gingival recession in each quadrant, participated in this study. One tooth per quadrant was assigned randomly to the control group or to one of the test groups that were treated with fluoride varnish, 1% CHX, or 40% CHX. The varnish treatment and the tooth cleaning were repeated every 3 months. Clinical examinations were performed at baseline and once a year for 3 years. Caries status and oral hygiene indices were evaluated clinically. The total cultivable microbiota and percentage of Mutans streptococci (MS), Actinomyces (ACC), and lactobacilli (LB) were analyzed.

RESULTS

Oral hygiene was improved greatly during the course of the study. The percentage of MS, ACC, and LB of the total cultivable microbiota revealed a statistically significant reduction between baseline and final examination for each of the four groups.

CONCLUSION

Professional tooth cleaning alone at 3-month intervals might be as effective in reducing MS, ACC, and LB as adjunctive treatment with fluoride or chlorhexidine.

Influences of orthodontic appliances on oral populations of mutans streptococci

A study was conducted to assess the influence of fixed appliances on the mutans streptococcal in a group of patients receiving orthodontic treatment. Mutans streptococcal counts in stimulated saliva of 27 patients were obtained at baseline, and at 1-month intervals for 4 months. The difference in mutans streptococcal counts at baseline and at the 4-month sampling was less than an order of magnitude in 18 of the patients, between 1 and 2 orders of magnitude in eight of the patients, and 3 orders of magnitude in one patient. Restriction endonuclease digests of genomic DNA from representative mutans streptococci isolates taken from baseline and 4-month saliva samples, as well as from 4-month tooth and appliance surfaces, were examined by pulsed field gel electrophoresis, after restriction endonuclease digestion. Results of the DNA banding patterns associated with isolates from 19 patients showed that, for 12 patients, all isolates examined represented the same clone of Streptococcus mutans, whereas for six patients two different S. mutans clones were detected. One patient yielded three different clones of S. mutans. A much larger number of baseline, as well as post-appliance, isolates will have to be examined from each patient in future studies, in order to determine if the number of different S. mutans clones harbored by individual patients is related to orthodontic treatment.

The effect of monitored chlorhexidine gel treatment on mutans streptococci in margins of restorations

OBJECTIVES

The objective of this study was to compare the effect of a monitored chlorhexidine (CHX) gel treatment with a conventional two-day CHX treatment in subjects with well-restored dentitions and high numbers of salivary mutans streptococci (MS).

METHODS

In the test group (n = 8), the effect of the CHX gel applications was monitored in margins of restorations and in saliva during a period of 12 weeks. Strip Mutans was used for monitoring and whenever a sample revealed growth of MS, the subject received a 3 x 5 min 1% CHX gel treatment at the clinic. Nine subjects (control group) were only given the baseline (conventional) treatment with CHX gel 3 x 5 min on two consecutive days.

RESULTS

The monitored treatment in the test group resulted in a more pronounced reduction of MS both in margins of restorations and in saliva than the conventional treatment. The difference between the level of MS in the margins in the two groups was, however, only significant at the 20-week examination. There was a large individual variation in the effect of the CHX treatment, and three to nine extra CHX gel applications were needed in the test group to keep MS below a detectable level during the 12 weeks.

CONCLUSIONS

Our findings illustrate the difficulties to obtain a long-lasting reduction of MS in subjects with a large number of restorations and a high number of MS by antimicrobial treatment only. The results indicate the necessity to combine antimicrobial treatment with, for example, sucrose restriction, in order to keep MS at a low level for a longer period of time.

A simple method for monitoring mutans streptococci in margins of restorations

Plaque material collected from margins of restorations using a sharp toothpick was streaked across one and the same plastic strip from a commercially available test kit and inoculated in a liquid medium containing bacitracin. The reproducibility of the method was good. The method is simple, inexpensive and suitable for the chairside demonstration of the colonization of mutans streptococci in localized areas of the mouth, such as margins of restorations.

Influence of salivary levels of mutans streptococci on colonization of crown margins: a longitudinal study

Initial colonization of mutans streptococci in 36 crown margins of 21 patients was studied. Before cementation, salivary concentrations of mutans streptococci and Lactobacillus sp, microorganisms associated with dental caries, were determined. Within 1 week 25% of the selected crown margins in subjects with low salivary levels of mutans streptococci and 89% in subjects with high salivary levels were colonized. High salivary counts of lactobacilli seemed to reflect conditions that enhanced the risk of colonization of mutans streptococci. The results suggest that, before cementation of fixed prosthodontics, measures should be taken to control the salivary concentrations of these organisms to reduce the susceptibility to recurrent caries.

Mutans streptococci in margins of fillings and crowns

A significant correlation was found between the number of mutans streptococci in saliva and the proportional distribution of these microorganisms in pooled plaque from the margins of all restorations. At high salivary numbers there was a tendency towards a higher porportion of mutans streptococci in plaque from the margins of separate restorations. At low and medium salivary numbers, plaque samples could, however, contain greater than 10 per cent mutans streptococci and even less than 1 per cent was found in plaque from margins of restorations at high salivary numbers. The reproducibility of the plaque sampling method was good. Plaque material collected on different occasions from the same margins did not vary significantly in terms of proportions of mutans streptococci. The numbers of mutants streptococci in plaque samples from different restorations of the same kind collected on the same occasion in the same mouth could, however, show a considerable variation. The observations made in this study, indicate that a low salivary number of mutans streptococci does not exclude a high proportion of these microorganisms in plaque from the margins of separate restorations. This has to be considered when efforts are made to reduce the risk of recurrent decay.

Mutans streptococci in plaque from margins of amalgam, composite, and glass-ionomer restorations

Levels of mutans streptococci in plaque samples from margins of Class II amalgam (Dispersalloy), composite (P-10), and glass-ionomer (Ketac Silver) restorations were compared. Fifty-one children, each having one of the restorations in a permanent first molar, were part of an inter-individual comparison, giving 17 restorations of each material. The age of the children, the age of the restorations, and the salivary levels of mutans streptococci were comparable in the three groups. Another seven children--each having both a composite and a glass-ionomer restoration of the same age placed on contralateral premolar or molar teeth--were part of an intra-individual comparison. The percentage mutans streptococci of total CFU count in plaque was higher on composite (mean 13.7) and amalgam (mean 4.3) than on glass-ionomer (mean 1.1) restorations in the inter-individual comparison, and higher on composite (mean 4.2) than on glass-ionomer (mean 0.4) restorations in the intra-individual comparison. In both comparisons, the differences in values between samples from glass-ionomer restorations and samples from composite or amalgam restorations were statistically significant (p less than 0.05).