Antibacterial Efficacy of Chlorhexidine Gluconate Intracanal Medication In Vivo

doi:10.1016/j.joen.2005.12.017

Journal of Endodontics

Volume 33, Issue 7, July 2007, Pages 788-795

https://doi.org/10.1016/j.joen.2005.12.017 Get rights and content

Abstract

The antibacterial efficacy of intracanal medication with 2% chlorhexidine liquid (CHX) was assessed in teeth with apical periodontitis. Canals in 22 teeth were instrumented at the first session, medicated with CHX, and reaccessed after 7 to 15 days. Bacteriological samples were aspirated at the first and second sessions, before (1A, 2A) and after (1B, 2B) canal instrumentation. Viable bacterial counts were obtained by culture (CFU) and microscopy using vital dyes. Microscopic counts were higher than CFU counts. Consistently high CFU counts in 1A samples (mean, 2 × 10⁵ μL⁻¹ canal volume) decreased significantly (p < 0.0001) in 1B samples, increased significantly (p < 0.04) in 2A samples, and decreased in 2B samples to the level of 1B samples. Proportions of negative cultures followed the pattern of CFU counts. Intracanal medication with CHX did not reduce the bacterial concentration. Bacterial counts expressed per microliter canal volume added information beyond the counts per tooth as expressed in previous studies.

Section snippets

Study Cohort

Before data collection, the research protocol was approved by the Health Sciences Research Ethics Board. Subjects were recruited from among patients in the Graduate Endodontics Clinic, Faculty of Dentistry, University of Toronto, Canada, in accordance with specific inclusion and exclusion criteria. Included were only premolar or anterior teeth presenting with radiographic evidence of apical periodontitis and with adequate coronal structure to ascertain proper isolation, temporization, and

Percentage of Negative Cultures

The proportions of samples showing no bacterial growth on agar plates (percentage negative culture) are summarized in Table 1. The statistical analysis of differences between samples is presented in Table 2. Not all of the access cavity (AC) samples were negative. The 1A samples all showed bacterial growth (positive culture). There was a significant increase (p < 0.001) in the percentage of negative cultures from the 1A to the 1B samples. The percentage of negative cultures decreased

Discussion

The accuracy of bacterial cultures obtained from root canals has been questioned (30), particularly the possibility of false-positive and -negative results. False-positive results can occur because of contamination during sampling, from salivary leakage, from bacteria retained in cracks and the margins of fillings (3, 30), or from handling of the specimens in the clinic or in the laboratory. False-negative results can occur when bacterial growth is inhibited by antibacterial agents used during

Acknowledgment

This study was supported in part by an Endodontic Research Grant from the American Association of Endodontists Foundation and by the Canadian Academy of Endodontics Endowment Fund.

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Periapical inflammation subsequent to coronal inoculation of dog teeth root filled with Resilon/Epiphany in 1 or 2 treatment sessions with chlorhexidine medication
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Therapeutic methods that inhibit microbial ingress into filled root canals are desirable. This in vivo study assessed the inhibition of periapical inflammation subsequent to coronal inoculation in canals medicated with 2% chlorhexidine gel and filled with Resilon/Epiphany (Pentron Clinical Technologies, Wallingford, CT).
Six Beagle dogs each had 10 two-rooted premolars treated. In group 1 (n = 36 roots), 1 root/tooth had the canal conditioned with Primer Epiphany, filled with Epiphany sealer and Resilon core in 1 session, and coronally sealed with PhotacFil. In group 2 (n = 36 roots), the second root/tooth had the canal medicated with 2% chlorhexidine gel for 1 week and then filled and coronally sealed as in group 1. After 3 weeks, canals were exposed to the oral environment for 7 days, inoculated with isologous plaque, and coronally sealed. Negative controls treated as groups 1 and 2 remained sealed. Positive controls had canals unfilled and exposed. Seven months after inoculation, dogs were euthanized; jaw blocks processed for histologic examination; and periapical inflammation (PI) recorded as none, mild, or severe.
In groups 1 and 2, severe PI occurred in 5 of 65 roots (8%) and mild PI in 18 of 65 roots (28%) with a significantly higher (P = .031) PI incidence in group 2 than in group 1. Negative controls had only mild PI in 9 of 29 roots (31%). Roots medicated with 2% chlorhexidine gel had mild PI significantly more (P = .009) than roots filled in 1 session (more than 2-fold).
Intracanal medication with 2% chlorhexidine gel and root filling with Resilon/Epiphany did not effectively inhibit apical periodontitis subsequent to coronal inoculation.
In vivo evaluation of microbial reduction after chemo-mechanical preparation of necrotic root canals with or without apical periodontitis
2014, Revista Portuguesa de Estomatologia, Medicina Dentaria e Cirurgia Maxilofacial
Assessment of bacterial reduction after chemo-mechanical preparation (using 3% sodium hypochlorite) with or without intracanal dressing (calcium hydroxide paste (Ca(OH)₂) or 2% chlorhexidine digluconate gel (CHX)) in necrotic pulps associated or not with apical lesion.
Prospective clinical trial, in 69 adult patient's teeth with pulpal necrosis associated or not with apical periodontitis. Microbiological root-canal-sampling occurred before treatment (S1), after chemo-mechanical preparation (S2) and after 14 days intracanal dressing (S3). Colony Forming Units (CFU) were counted after growth in aerobic, anaerobic and microaerofilic cultures. Comparison of the median CFUs treatments and culture media was done with the Friedman test. Comparison of the intracanal dressing effect at S3 was done with the Wilcoxon and the Mann–Whitney tests. Because of the huge differences in bacterial counts variations were expressed as log 10 to analyze differences among intracanal medication groups. S2 and S3 counts were expressed as percentage of CFU reduction regarding S1 counts.
Significant differences were detected between S1, S2 and S3 (Friedman test; p < 0.001), showing a significant decrease from S1 to S2 (Wilcoxon test; p < 0.004), followed by a significant increase from S2 to S3 (p < 0.001) for the CHX group, maintenance for the Ca(OH)₂ group in aerobic/anaerobic (Wilcoxon test; p = 0.777/0.227), and increase in the microaerofilic culture (Wilcoxon test; p = 0.047). The two groups only differed significantly in S3 (Mann–Whitney test; p ≤ 0.001), with a worse performance in the CHX group.
Treatment significantly reduced the number of bacteria but failed to render all root canals sterile. Ca(OH)₂ performed better than CHX gel.
Avaliar a eficácia da preparação químico-mecânica com ou sem medicação intracanalar (pasta de hidróxido de cálcio [Ca(OH)₂] ou gel de digluconato de clorhexidina a 2% [CHX]) no tratamento de dentes necrosados com ou sem lesão periapical.
Ensaio clínico prospetivo em 69 dentes monocanalares com necrose pulpar ou periodontite apical. A colheita microbiológica ocorreu antes do tratamento (S1), após preparação químico-mecânica (S2) e após 14 dias de medicação intracanalar (S3). Mediram-se as unidades formadoras de colónias (UFC) em aerobiose, anaerobiose e microaerofilia. As medianas de UFP de diferentes tratamentos e culturas foram comparadas com o teste de Friedman. A comparação do efeito da medicação intracanalar em S3 utilizou os testes Wilcoxon e t. Mann-Whitney. Dada a grande variabilidade de UFC nos distintos momentos de colheita, as diferenças entre S1, S2 e S3 foram traduzidas em logaritmos de 10. As contagens de S2 e S3 foram expressas como percentagem de redução de carga bacteriana relativamente a S1.
Encontraram-se diferenças significativas entre S1, S2 e S3 (teste Friedman; p < 0,001), com decréscimo significativo de S1 para S2 (teste Wilcoxon; p < 0,004), e aumento significativo de S2 para S3 (p < 0,001) no grupo de CHX, manutenção em aerobiose e anaerobiose (teste Wilcoxon; p = 0,777/0,227) e aumento em microaerofilia (teste Wilcoxon; p = 0,047) para o grupo experimental com Ca(OH)₂. Os 2 grupos só diferiram significativamente em S3 (teste Mann–Whitney; p ≤ 0,001), com pior desempenho da CHX.
O tratamento reduziu, de forma significativa, a carga bacteriana, mas não esterilizou os canais radiculares. O Ca(OH)₂ apresentou melhor desempenho que a CHX.
Detection of para-chloroaniline, reactive oxygen species, and 1-chloro-4-nitrobenzene in high concentrations of chlorhexidine and in a mixture of chlorhexidine and calcium hydroxide
2013, Journal of Endodontics
Chlorhexidine (CHX) is likely to decompose into reactive by-products. This study evaluated the generation of 4-chloroaniline (pCA), reactive oxygen species (ROS), and 1-chloro-4-nitrobenzene in high concentrations of CHX and in a mixture of CHX and calcium hydroxide at different time points.
A gas chromatography method was developed to detect pCA and CHX by-products. Mass spectroscopy was used to elucidate the structure of compounds. The samples, which were kept at 36.5°C and 95% relative humidity during the study, were analyzed immediately and 7 days after preparation.
pCA was detected in the 2% CHX solution and in the mixture of CHX and calcium hydroxide at all time points. pCA concentrations increased after storing under those conditions. The 2% CHX solution alone and the mixture of CHX and calcium hydroxide released ROS at all time points, but 1-chloro-4-nitrobenzene was not found.
pCA and ROS were identified as by-products of the 2% CHX aqueous solution alone and as ointment base of calcium hydroxide paste.
Influence of dentin from the root canal walls and the pulp chamber floor on the pH of intracanal medicaments
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The objective of this study was to evaluate the alterations in the pH of calcium hydroxide (Ca[OH]₂), 2% chlorhexidine (CHX) gel, and their combination after adding dentin powder from the root canal walls and the pulp chamber floor.
Ca(OH)₂ paste, 2% CHX gel, and their combination were examined. Dentin powder was obtained from the root canal walls and the pulp chamber floor of bovine teeth and added as 1.8% to the volume of the medications. The pH values of the mixtures were assessed immediately after preparation, after 24 hours, and on days 7 and 14. Data were analyzed statistically by analysis of variance and the Student's t test (P = .05).
pH values of Ca(OH)₂ were always above 12 in the presence or absence of dentin powder during the 14 days of the study. A significant decrease in pH values of Ca(OH)₂ was observed after 14 days when dentin from the root canal wall was added (P < .001). The pH values of CHX gel were significantly increased by the presence of dentin (P = .001). The t test showed a significant difference in the increase of the pH values when the different dentin types were added (P = .002). The pH of the Ca(OH)₂ and CHX gel combination was not influenced by dentin powder from the root canal walls, and a reduction was observed after 14 days, exactly like in the control group. The pH values of the combination did not alter after 14 days when pulp chamber floor dentin was added.
The different dentin types variably affect the pH of Ca(OH)₂ paste, 2% CHX gel, and their combination in the studied periods.
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Biofilm development is a dynamic process that begins with the initial attachment of planktonic bacteria to a surface, eventually leading through different stages to a mature, structurally complex biofilm. The aim of this study was to assess the effect of the source of biofilm bacteria, the level of biofilm maturation, and the type of disinfecting agent on the susceptibility of biofilm bacteria to antibacterial agents.
Multispecies biofilms from plaque bacteria of 6 donors were grown for up to 8 weeks on collagen-coated hydroxyapatite disks. After 1, 2, 3, 4, and 8 weeks of growth the biofilms were exposed to 1% sodium hypochlorite, 0.2/0.4% iodine-potassium iodide, and 2% chlorhexidine for 1 and 3 minutes. The percentage of killed biofilm bacteria was determined by using LIVE/DEAD viability staining and confocal laser scanning microscopy. One-way analysis of variance was used for statistical analysis.
One- and 2-week-old biofilms were moderately or very sensitive to the tested disinfecting agents, which killed 20%–100% of the biofilm bacteria. After 3 weeks of growth the biofilm bacteria were more resistant to the same agents, and only 10%–30% of the bacteria were killed (P < .001). The same pattern of the effect of biofilm age (maturation) on the resistance of bacteria was observed in all 6 biofilms and with all 3 disinfecting agents.
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Clinical researchAntibacterial Efficacy of Chlorhexidine Gluconate Intracanal Medication In Vivo

Abstract

Section snippets

Study Cohort

Percentage of Negative Cultures

Discussion

Acknowledgment

Oral Surg Oral Med Oral Pathol

J Endod

J Endod

J Endod

J Endod

J Endod

J Endod

Oral Surg Oral Med Oral Pathol Oral Radiol Endod

J Endod

J Endod

Oral Surg Oral Med Oral Pathol

J Endod

Oral Surg Oral Med Oral Pathol Oral Radiol Endod

J Endod

Bacteriological studies of necrotic pulpsDissertation

Influence of infection at the time of root filling on the outcome of endodontic treatment of teeth with apical periodontitis

Int Endod J

Microbiological examination of root canals and periapical tissues of human teethMethodological studies

Odontol Tidskr

Clinical research
Antibacterial Efficacy of Chlorhexidine Gluconate Intracanal Medication In Vivo