Effect of chlorhexidine varnish application on mutans streptococci counts in orthodontic patients.
BACKGROUND
Enamel demineralization occurs frequently around orthodontic brackets. High levels of mutans streptococci (MS) increase the risk of caries. The hypotheses tested in this study were that high-frequency application of 40% chlorhexidine varnish (40%CHX) results in lower levels of MS in plaque of orthodontic patients compared with low-frequency application, and that bimonthly application of 40%CHX results in lower levels of MS in plaque compared with 1% chlorhexidine/1% thymol varnish (1%CHX).


METHODS
Eighty adolescent patients were randomly allocated to 4 treatment groups: monthly, bimonthly, and quarterly 40%CHX application, and bimonthly application of 1%CHX. Plaque samples were collected monthly and processed for MS counts. Twenty patients dropped out before the evaluation time at 1 month. Data from the remaining 60 adolescents were analyzed by using linear regression models with the plaque bacterial ratio (PBRx) as the dependent variable. The trial was ended after 5 months because of a high number of dropouts.


RESULTS
High-frequency application of 40%CHX did not provide lower mean PBRx than low-frequency application. Mean PBRx after 40%CHX application was lower than 1%CHX after 1 month (P = .002). This reduction was undiscernible 2 months after the application.


CONCLUSIONS
40%CHX application results in greater reduction of MS in plaque than 1%CHX a month after application. A follow-up study with a larger study population is warranted to test the first hypothesis.
Derks
Aniek
A
Department of Orthodontics and Oral Biology, Radboud University Nijmegen Medical Centre, Nijmegen, the Netherlands.
Frencken
Jo
J
Bronkhorst
Ewald
E
Kuijpers-Jagtman
Anne Marie
AM
Katsaros
Christos
C
D000293:Adolescent; D000891:Anti-Infective Agents, Local / Q000009:adverse effects*; D002648:Child; D002710:Chlorhexidine / Q000008:administration & dosage*; D015169:Colony Count, Microbial; D003731:Dental Caries / Q000209:etiology / Q000382:microbiology / Q000517:prevention & control*; D003773:Dental Plaque / Q000382:microbiology; D004305:Dose-Response Relationship, Drug; D004334:Drug Administration Schedule; D004338:Drug Combinations; D006801:Humans; D016014:Linear Models; D016910:Orthodontic Brackets / Q000009:adverse effects; D010865:Pilot Projects; D013295:Streptococcus mutans / Q000187:drug effects*; D013943:Thymol / Q000008:administration & dosage
D000891:Anti-Infective Agents, Local; D004338:Drug Combinations; C477721:EC40 dental varnish; C079161:chlorhexidine, thymol drug combination; D013943:Thymol; D002710:Chlorhexidine