Introduction

Suture materials were originally derived from natural materials, such as animal tendons and cotton fibres which potentially lead to infections. Later synthetic suture materials and sterilization techniques led to a decrease in some postoperative infection. However, suture materials are still foreign bodies which tend to attract microbes like bacterial, fungi, viruses, etc. by wicking effect. Postoperative wound infections are one of the most common perioperative complications. Because of this, recent research has been focusing on avoiding bacterial colonization of sutures by using the various antibacterial coating. The antibacterial coating may prevent the adherence of bacteria on medical materials, but it is not possible to kill bacteria that adhere to suture materials, once a bio-film has formed (Donlan & Costerton, 2002).

Suture materials used during surgery carry a risk of postoperative wound infections and associated complications like bone infection, organ abscess, bacteraemia, endocarditis, sepsis (Giglio, Rowland, Dalton, & Laskin, 1992; King, Crawford, & Small, 1988; Otten, Wiedmann-Al-Ahmad, Jahnke, & Pelz, 2005).

Wound infections lead to more extended stays in hospital, requiring additional treatment, antibiotics, all of which cause a substantial increase in expenses (Zhan & Miller, 2003).

Oral flora is unique in each individual and changes the life of an individual. The commensal flora is always accompanied by opportunistic flora which is known to cause delayed wound healing (Otten, Pelz, & Christmann, 1987).

The presence of antibacterial coatings on sutures is thought to limit the ability of these opportunistic microbes to adhere, thereby preventing a delay in wound healing (Cruz et al., 2013; G, 2014).

Chlorhexidine (CHX) is a biguanide antiseptic with an antibacterial activity that has been in widespread use since the late 1940s. CHX, being positively charged, reacts with the negatively charged microbial cell membrane destroying its integrity. Subsequently, it penetrates the cell causing leakage of intracellular components, thereby leading to cell death.

CHX has shown high anti-infective efficacy in several studies involving orthopaedic (Darouiche et al., 1998; Kälicke et al., 2006), obstetric (Vorherr, Ulrich, Messer, & Hurwitz, 1980), surgical (Fardai & Turnbull, 1986) and dental applications (Karpiński & Szkaradkiewicz, 2015; Suido, Offenbacher, & Arnold, 1998).

CHX is minimally absorbed percutaneously and poorly absorbed across mucosal surfaces. CHX has been used in several pharmaceutical products due to its antiseptic properties and biocompatible nature (Harnet et al., 2009; Karde, Sethi, & Joshi, 2016; Obermeier et al., 2014).

In vitro studies have shown a zone of inhibition around the CHX coated suture materials as compared to be less as compared to triclosan coated sutures (Karde et al., 2016).

The aim of the presented study was a comparative analysis of bacterial colonization on conventional absorbable suture material as compared to antibacterial coated absorbable suture material in routine dentoalveolar surgery(third molar extractions). Investigations were concentrated on the total number of viable bacteria on the suture materials used.

Materials and Methods

The study examined two different suture materials- absorbable braided dyed polyglactin 910 (3‐0) (VICRYL^®, Ethicon) and absorbable braided dyed polyglactin 910 (3‐0) coated with Chlorhexidine (Petcryl ^®CS, Dolphin suture) as used in dentoalveolar surgery. Vicryl^® is a synthetic sterile resorbable surgical suture material consisting of a copolymer of 90% glycolid and 10% l-lactide (polyglactin 910). Petcryl ^® CS is a chlorhexidine coated polyglactin 910 suture material.

For three months, both suture materials were used for routine wound treatment in 17 patients (18–43 years old) who underwent third molar extractions. All 17 patients underwent extraction of two wisdom teeth on the same side at the same time. One operation site was closed by a Vicryl^® suture and the other by a Petcryl ^® CS suture. Post-operatively, all the sites were rinsed with saline only. The sutures were removed after seven days and transferred into sterile tubes containing transport medium.

Suture samples were agitated into test tubes containing 10 mL saline using a vortex mixer. Dilution of 10^{− 2} was prepared, and 0.1 ml of this dilution was plated on the blood agar plate using streak method. The agar plates were incubated aerobically at 37°C for 48 hours. Colonies of bacteria were counted using classical bacterial counting technique, and they expressed as a number of CFU/ml.

Results and Discussion

Total Number of Bacterial Colonies were expressed as colony-forming unit/ml or CFU/ml. The total number of bacteria was 37% higher on the Petcryl^® CS sutures (7.3×10⁸ colonies) than on those made of Vicryl^® (5.3×10⁸ colonies) (Table 1). Intraindividual variations in regards to bacterial colonies were found to be high (Table 2).

The treatment of SSI can be costly, and as prevention is better than cure, a preventive measure should be adopted to reduce the incidence of SSIs in post operated cases. Evidence of "loss of clot" as proposed by Nitzan in 1983 as pathogenesis of dry socket also postulates microbial adherence leading to fibrinolysis. Hence, bacterial adherence to sutures can be one of the reasons for dry socket.

Smart sutures are materials which respond to stimuli by altering one or more of their properties (Sivakumar & Naseem, 2016). They are covered with temperature sensors and micro-heaters which can detect infections, if coated with antibacterial drugs, they might be highly effective in the prevention of SSIs.

Despite controversial results amongst different clinical studies, the anti-microbial suture was more or less effective in decreasing the risk for postoperative SSIs in a broad population. Antibacterial sutures should possess better handling qualities, be non-carcinogenic, non-toxic, and free of allergens (Indhumathi & Kumar, 2019). Most anti-microbial sutures are coated with triclosan as it has proven to be effective in various extra-oral sites (Leaper et al., 2010; Leaper et al., 2011; Singh, Bartsch, Muder, & Lee, 2014).

However, there is innate resistance or high tolerability to triclosan in some bacterial strains through bacterial efflux pumps, but this may be of little clinical significance in regards to SSIs (Leaper et al., 2017).

A review of published literature for the use of triclosan coated sutures in the maxillofacial region illustrates the need for conscious decision making in the selection of suture materials post-surgery (Janani & Kumar, 2018). Sethi et al (Karde et al., 2016) used antibacterial coated suture to prevent the colonization of periodontal pathogens and inhibition of oral biofilm formation in vitro, a comparative evaluation of sutures coated with triclosan and CHX. Their analysis showed a maximum biofilm inhibition potential with CHX-coated suture followed by triclosan-coated suture. Large in vivo studies and clinical trials comparing different materials are necessary to validate the efficacy of CHX-coated sutures and their use in a clinical scenario.

Conclusions

The in vivo results for CHX coated sutures did not meet expectations for their use in the oral cavity. Because of the cost, the apparent disadvantage of no decrease in colony count, the use of CHX-coated sutures is not recommended by the authors. However, the study is limited to the fact that identification of an individual colony was not carried out. A larger randomized controlled trial may be carried out to evaluate the efficacy of CHX coated sutures.

Acknowledgment

The authors would like to thank Dr Ramvihari Thota for his tireless help in this study.

Funding Support

The authors declare funding support from a private firm.

Conflict Of Interest

The authors declare that they have no conflict of interest