The effect of orthodontic appliances on levels of Streptococcus mutans, Streptococcus sobrinus and microbial flora in saliva

Salivary flow rate, pH and buffering capacity in patients undergoing fixed orthodontic treatment - A prospective study

Background

Human saliva has got many important functions like lubrication of the oral tissues, making oral functions like speech, mastication and deglutition possible and also protecting teeth and oral mucosal surfaces in different ways. Dental Caries is one of the common complications in patients undergoing orthodontic treatment. Subjects with impaired saliva flow rate often show high caries incidence. A low flow rate combined with a low or moderate buffer effect clearly indicates poor salivary resistance against microbial attack.

Aim

To investigate the changes in stimulated and unstimulated salivary flow rate, pH and buffer capacity in patients undergoing therapy with fixed orthodontic appliances.

Materials and Methods

Salivary flow rate, pH and buffering capacity of 20 patients who underwent fixed orthodontic treatment at Department of Orthodontics, Ragas Dental College and Hospital, Chennai were examined using GC saliva check buffer kit. The procedure was carried out during the initiation of orthodontic treatment and subsequently, one month and six months after the placement of appliance.

Results

Results showed there was a significant increase in the salivary flow rate one month and six months after placement of fixed appliance while pH and buffering capacity showed no significant changes.

Conclusion

Salivary flow rate increases significantly during fixed orthodontic treatment. Salivary pH and buffering capacity showed no significant changes suggesting that they are not sole factors for demineralization in orthodontic patients.

Influence of salivary parameters in the caries development in orthodontic patients-an observational clinical study

BACKGROUND

Previous studies have shown during the orthodontic treatment, the prevalence of active caries lesions (ACL) in 30 to 70% of patients.

AIM

To evaluate the effect of orthodontic treatment on salivary properties considering caries development.

DESIGN

Twenty two individuals (11-22 years) were assessed regarding caries, oral hygiene, sugar exposure, salivary flow rate (SFR), buffering capacity, pH, carbonic anhydrase VI (CA VI) and amylase activity, at baseline, 1, 3 and 6 months after the orthodontic appliances placement. Caries index was determined by Nyvad criteria. CA VI and amylase activities were performed by zymography and ELISA, respectively.

RESULTS

Buffering capacity decreased after 3 months (P < 0.0001) and showed positive correlation with pH at baseline and after 1 month in individuals who did not develop active caries lesions. Amylase activity decreased after 1 and 6 months (P = 0.0003) and presented positive correlation with CA VI in patients who developed ACL. SFR increased after 1 month (P = 0.0283) and showed positive correlation with CA VI activity after 3 months in individuals who did not develop ACL. Salivary pH showed negative correlation with CA VI after 1 month in patients who did not develop ACL. ACL were firstly diagnosed after 3 months.

CONCLUSIONS

The present study demonstrated that saliva of individuals under orthodontic treatment is subjected to changes in properties that have implications on the onset of ACL.

Does the bracket composition material influence initial biofilm formation?

CONTEXT

Orthodontic treatment has been reported to contribute to the development and accumulation of dental biofilm, which is commonly found on bracket and adjacent surfaces.

AIMS

The aim of this work is to test the hypothesis if there are differences in dental biofilm formation on the surface of orthodontic brackets according to the type of composition material.

SUBJECTS AND METHODS

Three bracket types (metallic, composite, and ceramic) had been evaluated. Subjects wore acrylic palatal orthodontic appliances, containing 6 brackets each, for two 3-day cycles. On the end of first cycle, the amount of dental biofilm formed on the samples was extracted using 1.0-M NaOH and analyzed by spectrophotometry for quantification. An additional cycle was carried out to verify the dental biofilm formation using scanning electronic microscope analysis.

STATISTICAL ANALYSIS USED

Three-way ANOVA was used to analyze the difference among the materials (metallic, ceramic and composite) concerning the dental biofilm absorbance spectrum. Multiple comparisons were made using the Tukey's test (α =0.05).

RESULTS

Composite brackets showed greater values concerning biofilm formation, when compared with the metallic and ceramic ones, both of which presented similar scores. The hypothesis is accepted. There are differences on the biofilm formation according to the type of material.

CONCLUSIONS

The in situ model tested was found to be effective in evaluating the accumulation and development of biofilm on orthodontic brackets. In the quantitative analysis, composite brackets showed greater biofilm adhesion values while metallic and ceramic presented similar biofilm absorbance spectrum.

Effect of fixed orthodontic appliances on salivary microbial parameters at 6 months: a controlled observational study

Objective

The aim of this study was to assess the microbial changes in children with fixed orthodontic appliances compared with a control group of children without orthodontic treatment.

Material and Methods

Ninety-five children, aged between 12 and 16 years, participated in this study. Forty-eight subjects were fitted with fixed orthodontic appliances and forty-seven were free of any such appliances. The follow-up was 6 months for all children. The association between orthodontic appliances and high levels of Streptococcus mutans and Lactobacillus spp was assessed with logistic regression models, taking age, sex, pH and buffer capacity into account.

Results

Differences at baseline between the two groups were not statistically significant. We found that wearing a fixed orthodontic appliance was associated with high levels of Streptococcus mutans and Lactobacillus spp (adjusted OR: 6.65, 95% CI [1.98-22.37]; 9.49, 95% CI [2.57-35.07], respectively), independently of other variables.

Conclusion

The originality of the present epidemiological study was to evaluate the evolution of salivary microbial parameters in a population of children with fixed orthodontic appliances. Our results show an increase of Streptococcus mutans and Lactobacillus spp values during the follow-up. The whole dental workforce should be aware that preventive measures are of paramount importance during orthodontic treatment.

Antimicrobial effect of different brushing frequencies with fluoride toothpaste on Streptococcus mutans and Lactobacillus species in children with fixed orthodontic appliances

OBJECTIVE

To evaluate the antimicrobial effect of different frequencies of brushing with fluoride toothpaste on the levels of salivary mutans streptococci and lactobacilli in children undergoing fixed orthodontic treatment.

METHODS

The study included 22 patients scheduled for fixed orthodontic therapy distributed between 2 groups with different hygiene regimes. All the subjects received identical braces, bands, and brackets bonded with the same material. Stimulated saliva samples were obtained before placement of the appliance and at 6, 12, and 18 weeks during the therapy. Saliva samples were cultured on selective microbial agar for the detection of microorganisms.

RESULTS

Salivary mutans streptococci were significantly suppressed throughout the experimental period in the group that brushed 4 times a day as compared to the group that brushed twice a day. Salivary lactobacilli were not significantly affected by the frequency of brushing with 0.32% sodium fluoride (NaF) toothpaste.

CONCLUSIONS

The use of 0.32% NaF-containing toothpaste more than 3 times a day has effective antimicrobial activity on mutans streptococci but not lactobacilli in the saliva of children with fixed orthodontic appliances.

Salivary microbial and nonmicrobial parameters in children with fixed orthodontic appliances

OBJECTIVE

To determine the physiologic changes of salivary flow rate, pH, and buffer capacity and the levels of Streptococcus mutans and Lactobacillus spp in patients undergoing fixed orthodontic treatment.

MATERIALS AND METHODS

The study included 23 patients scheduled for fixed orthodontic therapy. All subjects received equal braces, bands, and brackets, bonded with the same material. Stimulated saliva samples were taken before placement of the appliance, and at weeks 6, 12, and 18 during the therapy. Salivary flow rate and salivary pH were measured, and the salivary buffer capacity was determined. Saliva samples were cultivated on selective microbial agar for microorganism detection.

RESULTS

A significant (P < .05) increase in stimulated salivary flow rate and salivary pH was found. The salivary levels of S mutans and Lactobacillus spp also inscreased significantly (P < .05), and the major peak was at week 12 of fixed orthodontic therapy.

CONCLUSION

The 6th to 12th week of orthodontic therapy is the period of the most intensive intraoral growth of S mutans and Lactobacillus spp and a time of very intensive salivary functions and physiologic response.

Behavior of NiTi in the presence of oral bacteria: corrosion by Streptococcus mutans

The aim of this study was to investigate the electrochemical behavior of nickel titanium (NiTi) orthodontic wires in a solution containing Streptococcus mutans oral bacteria. In this article, we explain our choice of bacterial species before describing the culture process in artificial saliva and the precautions needed to prevent contamination by other bacteria. The electrochemical behavior of the alloy (NiTi) was analyzed electrochemically in Ringer sterile artificial saliva and in artificial saliva enriched with a sterile broth and modified by addition of bacteria. The electrochemical procedures chosen for this study were: free corrosion potential, potentiodynamic curves and impedance spectroscopy. In this way, we were able to show that the free corrosion potential of the NiTi in the Ringer solution increases with time and then stabilizes, thus passivating the alloy. We also demonstrated that colonization of the metal surface by bacteria triggered a drop in the free corrosion potential. The electrochemical impedance findings revealed no significant difference in NiTi behavior between the two media. Finally, we observed a slight difference between the two corrosion currents in favor of the bacteria-enriched solution, in which the NiTi underwent greater corrosion. These findings demonstrate the impact of acidogenic bacteria on corrosion behavior of the NiTi wires investigated. However, further research is required, notably incorporating longer immersion times in the two media.