In vitro effects of calcium hydroxide and polymyxin B on endotoxins in root canals.
OBJECTIVE
To evaluate the effects of intracanal medicaments on endotoxins in root canals.


METHODS
Seventy-five freshly extracted maxillary incisors were used in this study. The crowns of teeth were sectioned near the CEJ in order to standardize the root length to 14 mm. The root canals were instrumented to an apical size #50 file and irrigated with 1% sodium hypochlorite solution and sterilized with 60Co gamma irradiation. Standardized suspension containing Escherichia coli endotoxin was inoculated into the 60 root canals. The specimens were randomly assigned to 5 groups (n=15), according to the intracanal medicament used: (G1) calcium hydroxide; (G2) polymyxin B; (G3) combination neomycin-polymyxin B-hydrocortisone; (G4) positive control (no intracanal medicament); (G5) negative control (no endotoxin and no intracanal medicament). After 7 days, the detoxification of endotoxin was evaluated by Limulus lysate assay and antibody production in B-lymphocytes culture.


RESULTS
Groups 1, 2 and 5 presented the best results by Limulus lysate and were significantly different to groups 3 and 4 (p<0.05). Stimulation of antibodies production in cell culture by groups 1 and 6 was smaller and statistically different than groups 2, 3, 4 and 5 (p<0.05). Groups 2 and 5 induced a small increase in the antibodies production in relation to the groups 1 and 6. Groups 3 and 4 induced a significant increase of antibodies production (p<0.05).


CONCLUSIONS
The calcium hydroxide and polymyxin B intracanal medicaments detoxified endotoxin in root canals and altered the properties of LPS to stimulate the antibody production by B-lymphocytes. The combination neomycin-polymyxin B-hydrocortisone did not detoxified endotoxin.
Oliveira
L D
LD
Department of Oral Biosciences and Diagnosis, School of Dentistry, Paulista State University-UNESP, Av. Eng. Francisco José Longo 777, São José dos Campos 12245-000, SP Brazil. luciane@fosjc.unesp.br
Leão
M V P
MV
Carvalho
C A T
CA
Camargo
C H R
CH
Valera
M C
MC
Jorge
A O C
AO
Unterkircher
C S
CS
D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D000893:Anti-Inflammatory Agents / Q000494:pharmacology; D000917:Antibody Formation / Q000187:drug effects; D001402:B-Lymphocytes / Q000187:drug effects / Q000276:immunology; D001427:Bacterial Toxins / Q000037:antagonists & inhibitors / Q000276:immunology; D002126:Calcium Hydroxide / Q000494:pharmacology*; D002478:Cells, Cultured; D003786:Dental Pulp Cavity / Q000187:drug effects*; D004338:Drug Combinations; D004731:Endotoxins / Q000037:antagonists & inhibitors* / Q000276:immunology; D004926:Escherichia coli / Q000276:immunology; D006801:Humans; D006854:Hydrocortisone / Q000494:pharmacology; D008033:Limulus Test; D008070:Lipopolysaccharides / Q000276:immunology / Q000494:pharmacology; D011112:Polymyxin B / Q000494:pharmacology*; D012388:Root Canal Irrigants / Q000494:pharmacology*
D000900:Anti-Bacterial Agents; D000893:Anti-Inflammatory Agents; D001427:Bacterial Toxins; D004338:Drug Combinations; D004731:Endotoxins; D008070:Lipopolysaccharides; D012388:Root Canal Irrigants; D011112:Polymyxin B; D002126:Calcium Hydroxide; D006854:Hydrocortisone