International Journal of Preventive and Clinical Dental Research

ORIGINAL ARTICLE
Year
: 2019  |  Volume : 6  |  Issue : 1  |  Page : 4--6

Quantitative and qualitative analyses of chlorhexidine substantivity in obturated root dentin: An in vitro study


MV Aarthi1, J Sreeja2, K Madhavadas3,  
1 Senior Lecturer, CSI College of Dental Sciences and Research, Madurai, Tamil Nadu, India
2 Associate Professor, Department of Conservative Dentistry, Government Dental College, Alappuzha, Kerala, India
3 Private Practitioner (Endodontist), Smile Craft Specialty Dental Clinic, Thiruvananthapuram, Kerala, India

Correspondence Address:
Dr. J Sreeja
Department of Conservative Dentistry, Government Dental College, Alappuzha, Kerala
India

Abstract

Objectives: The purpose of this investigation was to evaluate the substantivity of chlorhexidine (CHX) within the root canal system and to assess how long the CHX remains antimicrobially effective. Materials and Methods: Sixty freshly extracted intact human lower premolars with single root were collected, stored, and disinfected. The roots were divided randomly into two treatment groups: experimental (n = 30) and control (n = 30). Experimental samples (n = 30) were treated with 2% CHX and control samples (n = 30) were treated with sterile saline for 10 min. The samples were obturated with AH 26 sealer and gutta percha using lateral condensation technique. Each group was further randomly divided into three separate subgroups and stored in sterile saline for 1 week, 3 weeks, and 6 weeks. After the respective storage periods, all specimens were halved, and canal dentin was ground out with a peeso reamer. To determine whether the CHX from the dentin samples remained antimicrobial, the extracts from the experimental and control groups were mixed with the culture of Enterococcus faecalis. Results: Results were analyzed using one-way analysis of variance and Duncan's multiple range test, which showed statistically significant difference between the control and experimental groups with ultraviolet spectrophotometer for all storage periods but only till 3 weeks with antimicrobial tests. Conclusion: It can be concluded from this study that CHX is retained in the root canal in antimicrobial effective amounts for up to 3 weeks.



How to cite this article:
Aarthi M V, Sreeja J, Madhavadas K. Quantitative and qualitative analyses of chlorhexidine substantivity in obturated root dentin: An in vitro study.Int J Prev Clin Dent Res 2019;6:4-6


How to cite this URL:
Aarthi M V, Sreeja J, Madhavadas K. Quantitative and qualitative analyses of chlorhexidine substantivity in obturated root dentin: An in vitro study. Int J Prev Clin Dent Res [serial online] 2019 [cited 2019 Dec 13 ];6:4-6
Available from: http://www.ijpcdr.org/text.asp?2019/6/1/4/263458


Full Text



 Introduction



Microorganisms that invade the root canal system have an essential role in initiating and sustaining periapical disease by constant interaction with periradicular host tissues. Treatment of endodontic disease aims at exclusion of bacteria from the root canal system.[1] This goal may be accomplished by using mechanical instrumentation and chemical irrigation, coupled with medication of canal between treatment sessions.[2] Chlorhexidine (CHX) is a broad-spectrum antibacterial agent effective against many strains of Gram-positive and Gram-negative bacteria as well as yeast and facultative anaerobes and aerobes in the infected root canals. It is bactericidal at high concentrations and bacteriostatic at low concentrations. Important characteristics are protein binding and substantivity and low toxicity. The efficacy of various concentrations (0.12%–2%) of CHX either in solution or gel form used as endodontic irrigant against Enterococcus faecalis is also a well-known fact and has been a topic of interest for researchers in endodontics. Therefore, CHX has been suggested as a root canal irrigant owing to its unique ability to bind to dentin, its effectiveness as an antimicrobial agent, and its substantivity in the root canal system. The current study attempts to evaluate the substantivity of CHX within a root canal system and to assess how long after the root canal obturation the CHX remains antimicrobially effective.

 Materials and Methods



The current study was conducted at the Department of Microbiology, Sree Chitra Tirunal Institute for Medical Sciences and Technology, Thiruvananthapuram, India. Sixty freshly extracted human single-rooted, single-canal, lower premolar teeth were collected, stored, disinfected, and handled as per the recommendations and guidelines laid down by the occupational safety and health administration (OSHA) and the centers for disease control and prevention (CDC). Experimental samples (n = 30) were treated with 2% CHX, and control samples (n = 30) were treated with sterile saline for 10 min. After the experimental and control root samples were obturated, each group was further randomly divided into three separate “storage” groups to be placed in sterile saline for various time periods. The quantification of CHX was done using a spectrometer to read absorbency at 253 nm. To determine whether the residual CHX detected from dentin samples remained antimicrobial, the extracts were mixed with cultures of E. faecalis (ATCC 29212) that were kept in the log growth phase. One-way analysis of variance was performed as parametric test to compare observations at different weeks. Duncan's multiple range test was performed as post hoc comparisons. Control and experimental groups were compared using Student's t-test for each observation. Regression analysis between concentration and optical density of standard was employed to calculate the concentrations of CHX.

 Results



In the present study, regression analysis between concentration and optical density of standard was employed to calculate the concentrations of CHX. R2 for the regression graph was 0.99973, which indicates that a precision value was obtained when concentration and optical density are compared. This helps in determining the CHX retained in the root dentin precisely [Figure 1]. Although the concentration of CHX was retained in statistically significant amounts up to 6-week period, the antimicrobial activity was effective only up to 3 weeks. This may be because the concentration of CHX that is retained in the root canal in the 6 weeks (0.00163%) may not be sufficient enough to render antimicrobial activity [Table 1].{Figure 1}{Table 1}

 Discussion



CHX is suggested as an intracanal irrigant by a number of authors [3],[4],[5] and is the most commonly used irrigant in endodontics next to sodium hypochlorite.[6] 2% CHX is known to be particularly effective against many strains of bacteria found in the root canals.[3] In a study comparing common endodontic antimicrobials agents, 0.5% CHX was also significantly more effective at killing Candida albicans than Ca(OH)2, 5% and 0.5% NaOCl, and 2% I-KI.[7] The efficacy of CHX against E. faecalis has been the subject of study for many researchers.[8],[9] In the present study, it was found that CHX was retained in the root canal in antimicrobially effective amounts for at least 3 weeks. Previous studies that have investigated the substantivity properties of CHX in the root canal have also tested its presence in dentine for up to 3 weeks.[4],[10] Only the study conducted by Rosenthal et al., 2004, has determined its substantivity for up to 12 weeks.[9] These previous studies analyzed only the antimicrobial activity of CHX as a means to evaluate CHX substantivity.[1] In the current study, ultraviolet spectrophotometer was successfully used to estimate the amount of CHX that is retained in the dentin of the root canal wall along with the antimicrobial activity. Thus, this study evaluates CHX substantivity quantitatively as well as qualitatively. The obturated root specimens in the current study were lacking coronal restoration as a means to prevent interfering with the spectrophotometer absorbance value. This would have allowed for a potentially faster and more complex washout of CHX during the storage period than in a routine clinical setup. If a coronal restorative material has to be placed to mimic in vivo conditions, another wavelength that will be absorbed less by the coronal restoration and does not affect the values of CHX concentration should have been selected.[11],[12],[13] The fact that CHX with antimicrobial properties remained bound to root canal dentin, even after a long time period, is testament to the substantivity of CHX.[13]

 Conclusion



The present study concludes that CHX when used as an endodontic irrigant just before obturation can render antimicrobial activity for at least 3 weeks both quantitatively and qualitatively against E. faecalis. While these substantivity effects and antimicrobial properties of CHX are promising, it does not have the tissue-dissolving properties of NaOCl. Although NaOCl is still considered the most accepted irrigant, CHX may be considered advantageous as an irrigant prior to obturation, during retreatment or can even be incorporated into antimicrobial dressings.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

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