Compositional differences in multi-species biofilms formed on various orthodontic adhesives.
OBJECTIVE
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.
Department of Orthodontics, Seoul National University Dental Hospital.
Jung-Sub
JS
An
Department of Oral Microbiology and Immunology.
Kyungsun
K
Kim
Dental Research Institute.
Soha
S
Cho
Department of Dental Biomaterials.
Bum-Soon
BS
Lim
Department of Orthodontics, School of Dentistry, Seoul National University, Deahakno, Jongno-Gu, Seoul, Korea.
Sug-Joon
SJ
Ahn
D016976:Aggregatibacter actinomycetemcomitans / Q000254:growth & development / Q000302:isolation & purification; D001422:Bacterial Adhesion / Q000502:physiology; D018441:Biofilms / Q000254:growth & development*; D020770:Compomers; D003188:Composite Resins; D003738:Dental Cements; D005899:Glass Ionomer Cements; D006801:Humans; D016966:Porphyromonas gingivalis / Q000254:growth & development / Q000302:isolation & purification; D019279:Resin Cements; D013295:Streptococcus mutans / Q000254:growth & development / Q000302:isolation & purification; D016986:Streptococcus sobrinus / Q000254:growth & development / Q000302:isolation & purification; D013499:Surface Properties
D020770:Compomers; D003188:Composite Resins; D003738:Dental Cements; D005899:Glass Ionomer Cements; D019279:Resin Cements