Residual antibacterial activity of chlorhexidine digluconate and camphorated p-monochlorophenol in calcium hydroxide-based root canal dressings

Abstract

The purpose of this study was to evaluate the residual antibacterial activity of several calcium hydroxide [Ca(OH) 2 ]-based pastes, placed in root canals of dogs' teeth with induced chronic periapical lesions. Root canals were instrumented with the ProFile rotary system and filled with 4 pastes: G1 (n=16): Ca(OH) 2 paste + anesthetic solution; G2 (n=20): Calen ® paste + camphorated pmonochlorophenol (CMCP); G3 (n=18): Calen ® ; and G4 (n=18): Ca(OH) 2 paste + 2% chlorhexidine digluconate. After 21 days, the pastes were removed with size 60 K-files and placed on Petri plates with agar inoculated with Micrococcus luteus ATCC 9341. Pastes that were not placed into root canals served as control. After pre-diffusion, incubation and optimization, the inhibition zones of bacterial growth were measured and analyzed by Mann-Whitney U test at 5% significance level. All pastes showed residual antibacterial activity. The control samples had larger halos (p<0.05). The mean residual antibacterial activity halos in G1, G2, G3 and G4 were 7.6; 10.4; 17.7 and 21.4 mm, respectively. The zones of bacterial growth of G4 were significantly larger than those of G1 and G2 (p<0.05). In conclusion, regardless of the vehicle and antiseptic, all Ca(OH) 2 -based pastes showed different degrees of measurable residual antibacterial activity. Furthermore, unlike CMCP, chlorhexidine increased significantly the antibacterial activity of Ca(OH) 2 .

Histopathological evaluation of different methods of experimental induction of periapical periodontitis

“…This methodology for inducing periapical lesions in dog's teeth has also been used in other studies (4,5,6,(8)(9)(10)(11)18), which reported that after contamination of the root canals by oral pathogens or inoculation of microorganisms from the endodontic microbiota, coronal sealing reduced the time necessary for formation of radiographically visible periapical lesions. Studies have shown that when the occlusal cavities are sealed, the periapical inflammatory reaction is usually induced within 60 days (4,6,8,11,13), whereas in the teeth without coronal sealing induction of periapical periodontitis occurs only after 180 days (7,12,15).…”

“…Several studies have been performed in dogs to evaluate the root canal treatment of teeth with periapical lesions (3)(4)(5)(6)(7)(8)(9) or incomplete root formation (10)(11) and the healing process after periapical surgery (12)(13).…”

Resposta celular e molecular do tecido conjuntivo de camundongos e medicações intracanal

“…Com o objetivo de potencializar o efeito antimicrobiano do Ca(OH) 2 , tem sido proposta, como medicação intracanal, a utilização da pasta de Ca(OH) 2 associada à CHX em concentrações de 0,12% a 2% (Evans et al, 2003;Sirén et al, 2004;Ercan et al, 2006;Soares et al, 2006a;Soares et al, 2007;Onçag et al, 2006;Manzur et al, 2007;Al-Nazhan e Al-Obaidae, 2008;Gomes et al, 2009b;Silva et al, 2009;Valera et al, 2009;2010;Delgado et al, 2010;Gondim et al, 2011;Lima et al, 2011). Essa associação resulta em um efeito antimicrobiano sinérgico (Evans et al, 2003;Podbielski et al, 2003;Zehnder et al, 2003;Zarella et al, 2005;Soares et al, 2007;Souza-Filho et al, 2008;Lima et al, 2011), sem alteração da solubilidade, alcalinidade ou atividade de ambas as substâncias (Podbielski et al, 2003;Basrani et al, 2003;Sirén et al, 2004;Signoretti et al, 2011).…”

“…Essa associação resulta em um efeito antimicrobiano sinérgico (Evans et al, 2003;Podbielski et al, 2003;Zehnder et al, 2003;Zarella et al, 2005;Soares et al, 2007;Souza-Filho et al, 2008;Lima et al, 2011), sem alteração da solubilidade, alcalinidade ou atividade de ambas as substâncias (Podbielski et al, 2003;Basrani et al, 2003;Sirén et al, 2004;Signoretti et al, 2011). No entanto, não há consenso na literatura se a adição da CHX ao Ca(OH) 2 prejudica/altera a reação do tecido conjuntivo (Semenoff et al, 2008;Silva et al, 2009).…”

“…Deste modo, o principal objetivo do tratamento endodôntico de dentes com necrose pulpar e lesão periapical é a redução ou eliminação da infecção microbiana no sistema de canais radiculares (Evans et al, 2003;Wuerch et al, 2004;Kanisavaran, 2008;Mohammadi e Abbott, 2009b;Kawashima et al, 2009). O preparo biomecânico, empregando instrumentos manuais ou rotatórios, associado a soluções irrigadoras, visa, dentre outras finalidades, ao combate à infecção (Leonardo, 2005;Soares et al, 2007;Young et al, 2007). Entretanto, como os micro-organismos não se encontram localizados somente na luz do canal radicular principal Leonardo, 2005), o preparo biomecânico, isoladamente, não é eficaz na sua eliminação (Leonardo et al, 1994;Basrani et al, 2003;Faria et al, 2005;El Karin et al, 2007;Paula-Silva et al, 2010).…”