Variation in adhesion of Streptococcus mutans and Porphyromonas gingivalis in saliva-derived biofilms on raw materials of orthodontic brackets.

Objective: To evaluate differences in the adhesion levels of the most common oral pathogens, Streptococcus mutans and Porphyromonas gingivalis , in human saliva-derived microcosm biofilms with respect to time and raw materials of orthodontic brackets. Methods: The samples were classified into three groups of bracket materials: 1) monocrystalline alumina ceramic (CR), 2) stainless steel metal (SS), and 3) polycarbonate plastic (PL), and a hydroxyapatite (HA) group was used to mimic the enamel surface. Saliva was collected from a healthy donor, and saliva-derived biofilms were grown on each sample. A real-time polymerase chain reaction was performed to quantitatively evaluate differences in the attachment levels of total bacteria, S. mutans and P. gingivalis at days 1 and 4. Results: Adhesion of S. mutans and P. gingivalis to CR and HA was higher than the other bracket materials (SS = PL < CR = HA). Total bacteria demonstrated higher adhesion to HA than to bracket materials, but no significant differences in adhesion were observed among the bracket materials (CR = SS = PL < HA). From days 1 to 4, the adhesion of P. gingivalis decreased, while that of S. mutans and total bacteria increased, regardless of material type. Conclusions: The higher adhesion of oral pathogens, such as S. mutans and P. gingivalis to CR suggests that the use of CR brackets possibly facilitates gingival inflammation and enamel decalcification during orthodontic treatment.

Compositional differences in multi-species biofilms formed on various orthodontic adhesives.

OBJECTIVES: To investigate the aspects of multi-species biofilm formation on various orthodontic adhesives with different surface characteristics. METHODS: Multi-species biofilms using 13 bacterial species were grown on the surfaces of composite, compomer, and resin-modified glass-ionomer cement (RMGI). The changes in Streptococcus mutans (Sm), Streptococcus sobrinus (Ss), Porphyromonas gingivalis (Pg), Aggregatibacter actinomycetemcomitans (Aa), and total bacteria were determined at day 1 (T1) and day 4 (T2) using real-time polymerase chain reaction. Surface roughness (SR), surface free energy (SFE), and surface texture were analyzed to explain the differences in bacterial compositions among the adhesives. Repeated measures analysis of variance was used to determine time-related changes in bacterial compositions with respect to adhesive type. The Kruskal-Wallis test was used to determine differences in SR and SFE among the adhesives. RESULTS: There were no significant differences in the adhesion of total bacteria among the adhesives; however, the adhesion of Sm, Ss, and Pg was higher to RMGI than the other adhesives. The amount of Sm, Ss, and total bacteria increased from T1 to T2, while Pg and Aa decreased from T1 to T2. RMGI showed a rougher surface relative to composite or compomer due to the presence of micro-pores and/or flaws. Compomer had the greatest SFE followed by RMGI and composite. Interestingly, SR differences were about 10 times greater than SFE differences among the adhesives. CONCLUSIONS: Considering the greater differences in SR than SFE among the adhesives, the rougher surface of RMGI may cause greater adhesion of Sm, Ss, and Pg.

Antimicrobial and physical characteristics of orthodontic primers containing antimicrobial agents.

OBJECTIVE: To compare the antimicrobial and physical properties of experimental primers containing chlorhexidine (CHX) or ursolic acid (UA) with a commercial primer. MATERIALS AND METHODS: Two antibacterial agents, 3 mg each of CHX and UA were incorporated respectively into 1 ml of Transbond XT primer (TX) to form antibacterial primers, TX-CHX and TX-UA. The antimicrobial activity of the three primers (TX, TX-CHX, and TX-UA) against Streptococcus mutans in both planktonic and biofilm phases was analyzed by determining minimum inhibitory and bactericidal concentrations and by performing growth and biofilm assays. Growth and biofilm assays were performed in both the absence and presence of thermocycling in a water tank to analyze the effects of water aging on the antimicrobial activities of primers. After bonding brackets onto bovine incisors using the primers, shear bond strength and mode of fracture were analyzed to compare physical properties. RESULTS: TX-CHX had stronger antimicrobial activity against S. mutans in the planktonic and biofilm phases than did TX or TX-UA. When applied, TX-CHX completely inhibited the growth and biofilm formation of S. mutans . In addition, the antimicrobial activity of TX-CHX was maintained after thermocycling. However, TX-UA did not show significant antimicrobial activity compared with TX. There was no significant difference in either shear bond strength or bond failure interface among the primers. CONCLUSION: Incorporation of CHX into an orthodontic primer may help prevent enamel demineralization around surfaces without compromising its physical properties.

Changes in salivary periodontal pathogens after orthodontic treatment: An in vivo prospective study.

OBJECTIVE: To analyze the initial changes in salivary levels of periodontal pathogens after orthodontic treatment with fixed appliances. MATERIALS AND METHODS: The subjects consisted of 54 adult patients. The Simplified Oral Hygiene Index, Plaque Index, and Gingival Index were measured as periodontal parameters. Both the plaque and gingival indexes were obtained from the central and lateral incisors and first molars of both arches. Whole saliva and periodontal parameters were obtained at the following four time points: immediately before debonding (T1), 1 week after debonding (T2), 5 weeks after debonding (T3), and 13 weeks after debonding (T4). Repeated measures analysis of variance was used to determine salivary bacterial levels and periodontal parameters among the four time points after quantifying salivary levels of Aggregatibacter actinomycetemcomitans (Aa), Fusobacterium nucleatum (Fn), Porphyromonas gingivalis (Pg), Prevotella intermedia (Pi), Tannerella forsythia (Tf), and total bacteria using the real-time polymerase chain reaction. RESULTS: All periodontal parameters were significantly decreased immediately after debonding (T2). The salivary levels of total bacteria and Pg were decreased at T3, while Pi and Tf levels were decreased at T4. However, the amount of Aa and Fn remained at similar levels in saliva during the experimental period. Interestingly, Aa and Fn were present in saliva at higher levels than were Pg, Pi, and Tf. CONCLUSION: The higher salivary levels of Aa and Fn after debonding suggests that the risk of periodontal problems cannot be completely eliminated by the removal of fixed orthodontic appliances during the initial retention period, despite improved oral hygiene.

Adhesion of periodontal pathogens to self-ligating orthodontic brackets: An in-vivo prospective study.

INTRODUCTION: Our aims were to analyze adhesion of periodontopathogens to self-ligating brackets (Clarity-SL [CSL], Clippy-C [CC] and Damon Q [DQ]) and to identify the relationships between bacterial adhesion and oral hygiene indexes. METHODS: Central incisor brackets from the maxilla and mandible were collected from 60 patients at debonding after the plaque and gingival indexes were measured. Adhesions of Aggregatibacter actinomycetemcomitans (Aa), Porphyromonas gingivalis (Pg), Prevotella intermedia (Pi), Fusobacterium nucleatum (Fn), and Tannerella forsythia (Tf) were quantitatively determined using real-time polymerase chain reactions. Factorial analysis of variance was used to analyze bacterial adhesion in relation to bracket type and jaw position. Correlation coefficients were calculated to determine the relationships between bacterial adhesion and the oral hygiene indexes. RESULTS: Total bacteria showed greater adhesion to CSL than to DQ brackets, whereas Aa, Pg, and Pi adhered more to DQ than to CSL brackets. CC brackets showed an intermediate adhesion pattern between CSL and DQ brackets, but it did not differ significantly from either bracket type. Adhesion of Fn and Tf did not differ significantly among the 3 brackets. Most bacteria were detected in greater quantities in the mandibular than in the maxillary brackets. The plaque and gingival indexes were not strongly correlated with bacterial adhesion to the brackets. CONCLUSIONS: Because Aa, Pg, and Pi adhered more to the DQ brackets in the mandibular area, orthodontic patients with periodontal problems should be carefully monitored in the mandibular incisors where the distance between the bracket and the gingiva is small, especially when DQ brackets are used.

Changes in salivary periodontal pathogens after orthodontic treatment: An in vivo prospective study.

OBJECTIVE: To analyze the initial changes in salivary levels of periodontal pathogens after orthodontic treatment with fixed appliances. MATERIALS AND METHODS: The subjects consisted of 54 adult patients. The Simplified Oral Hygiene Index, Plaque Index, and Gingival Index were measured as periodontal parameters. Both the plaque and gingival indexes were obtained from the central and lateral incisors and first molars of both arches. Whole saliva and periodontal parameters were obtained at the following four time points: immediately before debonding (T1), 1 week after debonding (T2), 5 weeks after debonding (T3), and 13 weeks after debonding (T4). Repeated measures analysis of variance was used to determine salivary bacterial levels and periodontal parameters among the four time points after quantifying salivary levels of Aggregatibacter actinomycetemcomitans (Aa), Fusobacterium nucleatum (Fn), Porphyromonas gingivalis (Pg), Prevotella intermedia (Pi), Tannerella forsythia (Tf), and total bacteria using the real-time polymerase chain reaction. RESULTS: All periodontal parameters were significantly decreased immediately after debonding (T2). The salivary levels of total bacteria and Pg were decreased at T3, while Pi and Tf levels were decreased at T4. However, the amount of Aa and Fn remained at similar levels in saliva during the experimental period. Interestingly, Aa and Fn were present in saliva at higher levels than were Pg, Pi, and Tf. CONCLUSION: The higher salivary levels of Aa and Fn after debonding suggests that the risk of periodontal problems cannot be completely eliminated by the removal of fixed orthodontic appliances during the initial retention period, despite improved oral hygiene.