Efficacy of endodontic treatment for endotoxin reduction in primarily infected root canals and evaluation of cytotoxic effects.
BACKGROUND
Endotoxins are one of the etiologic agents involved in the pathogenesis of apical periodontitis. The objectives of this clinical study were to investigate the effects of endodontic treatment by using different irrigants on endotoxins in root canals with pulp necrosis and apical periodontitis and to evaluate the cytotoxic effects.


METHODS
Thirty-six root canals were selected. Samples were collected before (S1) and after instrumentation (S2). The root canals were divided into 3 groups (n = 12) according to the irrigant combination used: CLX + LW, 2% chlorhexidine gel + calcium hydroxide (0.14%, limewater); CLX + PmB, chlorhexidine + polymyxin B; CLX (control), chlorhexidine + saline. The third sampling (S3) was performed after ethylenediaminetetraacetic acid and S4 after intracanal medication (CLX + calcium hydroxide for 14 days). Endotoxins were quantified by the chromogenic Limulus amebocyte lysate assay, and cytotoxic effects were evaluated by the production of cytokines (interleukin-1ß, tumor necrosis factor α) in macrophages (RAW 264.7) stimulated with the root canal content.


RESULTS
Endotoxins were detected in all root canals before instrumentation (S1). Group CLX + LW presented the greatest endotoxin reduction after instrumentation (99.18%), which was similar to group CLX + PmB (96.42%, P > .05) and different from group CLX (90.78%, P < .05). The intracanal medication promoted important endotoxin neutralization, with a reduction of 99.2% to 100%. The root canal content induced a higher production of tumor necrosis factor α and interleukin-1β in S1 samples compared with samples obtained after treatment.


CONCLUSIONS
The combination of CLX and limewater as irrigant was the most effective in reducing endotoxins in root canals, and intracanal medication was important to neutralize the cytotoxic effects.
Department of Biosciences and Oral Diagnosis, Universidade Estadual Paulista/UNESP, São José dos Campos, Saõ Paulo, Brazil. luciane@fosjc.unesp.br
Luciane Dias de
LD
Oliveira
Cláudio Antonio Talge
CA
Carvalho
Alessandra Sverberi
AS
Carvalho
Jéssica de Souza
Jde S
Alves
Marcia Carneiro
MC
Valera
Antonio Olavo Cardoso
AO
Jorge
D000328:Adult; D000818:Animals; D002126:Calcium Hydroxide / Q000627:therapeutic use; D002460:Cell Line; D002710:Chlorhexidine / Q000627:therapeutic use; D003786:Dental Pulp Cavity / Q000187:drug effects*; D003790:Dental Pulp Necrosis / Q000628:therapy*; D004492:Edetic Acid / Q000627:therapeutic use; D004731:Endotoxins / Q000032:analysis* / Q000037:antagonists & inhibitors; D006090:Gram-Negative Bacteria; D006801:Humans; D053583:Interleukin-1beta / Q000032:analysis; D008033:Limulus Test; D008264:Macrophages / Q000187:drug effects; D051379:Mice; D008875:Middle Aged; D010485:Periapical Periodontitis / Q000628:therapy*; D011112:Polymyxin B / Q000627:therapeutic use; D012388:Root Canal Irrigants / Q000627:therapeutic use*; D012390:Root Canal Therapy / Q000379:methods*; D012965:Sodium Chloride; D016896:Treatment Outcome; D014409:Tumor Necrosis Factor-alpha / Q000032:analysis; D055815:Young Adult
D004731:Endotoxins; D053583:Interleukin-1beta; D012388:Root Canal Irrigants; D014409:Tumor Necrosis Factor-alpha; D012965:Sodium Chloride; D004492:Edetic Acid; D011112:Polymyxin B; D002126:Calcium Hydroxide; D002710:Chlorhexidine