Bacterial adherence to silk and nylon sutures

LAUANE ALVES1 | ANA BARBARA POLO2 | NEUZA MARIA SOUZA PICORELLI ASSIS3 | BRENO NOGUEIRA SILVA3 | ANA CAROLINA MORAIS APOLÔNIO2 | MATHEUS FURTADO DE-CARVALHO3

Introduction: Suture threads are important substrates for microbial adhesion in oral surgeries. It was proposed to compare bacterial adhesion in silk and nylon sutures when impregnated or not with an antiseptic ointment based on iodoform and marigold. Methods: A prospective, randomized, double-blind, divided mouth trial was conducted. After extractions in one of the hemiarchs, a simple suture was performed with the nylon thread (group A) and another simple suture with the silk thread (group B) impregnated with the antiseptic ointment. At the same surgical moment, extractions were performed in the contralateral hemiarch and simple suture with nylon thread (group C) and silk thread (group D) without antiseptic ointment. The Student’s t-test compared the means of colony-forming units (CFUs), while the Friedman test analyzed the distribution of bacterial adhesion in each group. Results: The average of bacterial adhesion was higher in silk suture with antiseptic ointment (M = 5.7288log/CFU/mL) and lower in nylon suture without ointment (M = 4.0587log/CFU/mL). Conclusion: Despite the antiseptic composition of the ointment, it is noted that its impregnation, both with silk thread and nylon thread, did not reduce bacterial adhesion in the sutures.

Keywords: Colony count. Microbial. Sutures. Surgery, oral.

1 Universidade Federal de Juiz de Fora, Departamento de Odontologia (Juiz de Fora/MG, Brazil).

2Universidade Federal de Juiz de Fora, Departamento de Parasitologia, Microbiologia e Imunologia (Juiz de Fora/MG, Brazil).

3Universidade Federal de Juiz de Fora, Departamento de Clínica Odontológica (Juiz de

Fora/MG, Brazil). How to cite: Alves L, Polo AB, Assis NMSP, Silva BN, Apolônio ACM, de-Carvalho MF. Bacterial adherence to silk and nylon sutures. J Braz Coll Oral Maxillofac Surg. 2021 Jan-Apr;7(1):38-42. DOI: https://doi.org/10.14436/2358-2782.7.1.038-042.oar

Submitted: June 22, 2020 - Revised and accepted: September 22, 2020

» The authors report no commercial, proprietary or financial interest in the products or companies described in this article.

Contact address: Matheus Furtado de-Carvalho Rua São Mateus, 270, apto. 601, bairro São Mateus CEP: 36.025-000 – Juiz de Fora/MG E-mail: matheus.furtado@ufjf.edu.br

Synthesis corresponds to the surgical maneuver that aims to tie the blood vessels and bring the tissues closer by sutures or adhesives. In oral surgery, the main objective is to reposition and maintain the stability of surgical flap, assisting in tissue repair. Also, it contributes to preservation of the clot in the dental socket and local hemostasis.1

Sutures are important substrates for microbial adhesion2 and can become a factor of tissue aggression when associated with foreign body reactions, and lead microorganisms into the wound, even causing bacteremia.3

Microbial adhesion depends directly on the material that constitutes the suture (silk, nylon, cotton, collagen) and has different capacities to absorb fluids and secretions from the oral environment. Microbial colonization is also related to the filamentary structure of sutures. Multifilament sutures, such as silk, are braided and more prone to microbial adhesion, while single-stranded sutures, such as nylon, hinder microbial colonization.4

In an attempt to minimize microbial adhesion and enhance tissue repair, some researchers advocate the use of antiseptic substances, such as tetracycline, chlorhexidine, propolis and marigold, on the surface of sutures.5-8 An ointment made of iodoform and calendula was effective in controlling aerobic and anaerobic microorganisms when applied inside dental implants, with satisfactory pharmacological stability to remain active in place between 1 and 5 years.9 Thus, the objective is to use the same aforementioned product and to compare bacterial adhesion on silk and nylon sutures, impregnated or not with iodoform and marigold oil antiseptic ointment.

The study was approved by the Institutional Review Board of the Federal University of Juiz de Fora (CAAE 92790318.1.0000.5147), under report N. 2869833, in compliance with the Declaration of Helsinki.

This is a prospective clinical trial, double blind, split-mouth, applied to 16 participants obtained from a convenience sample based on the search for patients in need of simple extraction. After that, patients of both sexes, aged over 18 years, who had multiple tooth extractions (minimum of two teeth) in both dental hemiarches were included. Patients with diabetes, hypertension, anemia, malnutrition and with alveolar suppuration capable of interfering with tissue repair, patients allergic to the ointment components and patients with reports of use of antimicrobials in the last 15 days were excluded.

The random sequence was generated by the Random Allocation Software 2.0 program, and randomization was organized by the strategy of random numbers on the Microsoft Excel software. Multiple extractions were performed in the same surgical procedure. In one of the hemiarches, a simple suture was performed with nylon (group A) and another suture with silk (group B), with spacing of 1 cm. The sutures were manually impregnated with 0.1 g of the antiseptic ointment on its free end (Fig 1). The ointment is composed of iodoform (12.85%) and marigold oil (4.1%), with excipients fatty acid esters, hydrocarbons, propylparaben and hydroxytoluene butylated (BHT). In the contralateral hemiarch there was no impregnation of ointment in nylon (group C) and silk (group D) sutures. For suture, silk and nylon sutures, black, 4-0 diameter manufactured by Ethicon (Johnson & Johnson, São Paulo, São Paulo, Brazil) were used, constituting an initial sample of 64 sutures.

All participants performed a preoperative mouthwash using 15 ml of 0.12% chlorhexidine digluconate solution for 1 minute. Participants were medicated with analgesics and instructed about postoperative care, which included daily brushing of adjacent teeth and mouthwash with running water after 48 hours. Mouthwash with 0.12% chlorhexidine digluconate was not prescribed to avoid possible interference with the research results.

The suture was removed on the seventh postoperative day, obtaining a 5mm fragment of the suture exposed to the oral mucosa. Each sample was transferred to a sterile Eppendorf centrifuge microtube, containing 1.5 ml of 0.85% saline solution, labeled and preserved on ice in a thermal container, for a maximum period of 2 hours, until processing in the Laboratory of the Department of Parasitology, Microbiology and Immunology.

In the laboratory, each microtube was shaken in the Vortex Biomixer device (Biomol, Ribeirão Preto/ SP, Brazil) for a maximum of 12 rotations for 5 minutes and the suspension was diluted to 10-5 in 0.85% saline, i.e., 100 microliters for every 900 microliters of 0.85% saline, alternating with 10 minutes of stirring at each dilution (Fig 2).

Figure 1: Impregnation of suture with the antiseptic ointment. Figure 2: Laboratory step of serial dilution.

The samples were seeded (100 microliters) in Brain Heart Infusion (BHI) medium, from dilutions 10-3, 10-4 and 10-5, in duplicate, and incubated in microaerophilia at 37°C for 48 hours, for later counting of number of colony-forming units (CFU) of dilutions that grew 30 to 300 colonies (Fig. 3). The calculation to obtain the bacterial quantity present in each fragment of suture was obtained by the formula: CFU/mL = n (number of colonies counted)x10 (correction factor)x10x (inverse of dilution)/1.5 and expressed on a logarithmic scale (log CFU/mL).

Data were analyzed using the SPSS version 21 software. The Shapiro-Wilk normality test was used to determine if the variables had normal distribution. The bacterial adhesion measured in log CFU/mL was the continuous quantitative dependent variable, and the types of sutures (nylon and silk) impregnated or not with antiseptic ointment were considered the independent variables. The paired Student’s t-test was used to compare the mean CFU in groups two by two, following the evaluations between the presence or not of ointment for the same type of suture (nylon: group A with group C; and silk) : group B with group D) and, later, by the type of suture impregnated with the antiseptic ointment (group A with group B). To analyze the distribution of bacterial adhesion, the Friedman test was used in each group. Values of p≤0.05 were considered significant.

Figure 3: Growth of CFUs in BHI medium, at 10-3 dilution.

Table 1: Mean quantification of bacteria present in the different groups of sutures.

Group A) Nylon suture with ointment* B) Silk suture with ointment* C) Nylon suture without ointment* D) Silk suture without ointment*

* p≤0.05.

4.8229 14

5.7288 16

4.0587 5.3250 15 16

Standard deviation 1.01288 0.74399 1.01886 0.76319

Among the 16 study participants, 7 (43.75%) were females and 9 (56.25%) were males. The mean age of participants was 20 years. The study included a final sample of 61 sutures. There was a sample loss of 1 suture due to failure in microtube sealing and another 2 due to inadequate CFU growth. All patients returned for suture removal and showed no signs and symptoms of surgical complications.

Among the four groups, the mean bacterial adhesion was higher in silk with ointment and lower in nylon without ointment. Also, it was noted that the mean bacterial adhesion on nylon impregnated with ointment was higher than when nylon was used without the ointment. A similar result was found in bacterial colonization of silk with the ointment, in which the mean bacterial adhesion was higher compared to silk without ointment (Table 1).

According to Arteagoitia et al.,10 chlorhexidine has been the most used antiseptic solution for preoperative mouthwashes in tooth extractions and can be used in different concentrations, preventing bacteremia in 12% of cases. In the present study, mouthwash with 0.12% chlorhexidine was adopted. Larsen11 noticed a 60% reduction in the incidence of alveolitis using this same concentration in the preoperative removal of unerupted lower third molars. Ugwumba et al.12 recommend chlorhexidine at a concentration of 0.2%, aiming to reduce the risk of bacteremia.

Mahesh et al.13 emphasize that the choice of suture in oral surgeries depends on the location, extent and area of exposure of the wound. In the present study, simple extractions of posterior teeth were performed, which allowed primary wound closure. There is consensus that nylon produces minimal acute inflammatory reaction in oral tissues, being an excellent option in periodontal and peri-implant esthetic surgery of anterior teeth, due to its composition with long chain aliphatic, which precludes bacterial adhesion.14 However, they may cause greater discomfort to the patient, due to their rigidity, inhibiting their use in surgeries close to the tongue and buccal mucosa.

Conversely, it is known that silk suture has filaments of natural protein that allow softness and elasticity, providing greater security of the knot and distension along the swollen tissues. However, they have high capillarity as a disadvantage. Some authors believe that their impregnation with different compounds can minimize unwanted bacterial colonization.5-7

The present study adopted an antiseptic ointment based on iodoform and marigold. Iodoform is poorly soluble in water (1:1000) and its volatility in contact with organic liquids slowly releases iodine, which generates a smooth and persistent antiseptic action.15 Marigold oil, extracted from the herbal plant Calendula officinalis, has antimicrobial action.5 The mouthwash made of Calendula officinalis provided less bacterial adhesion on silk suture after third molars extraction when compared to the control group, and greater bacterial adhesion when compared to 0.12% chlorhexidine digluconate mouthwash.6

The microbial stability of a pharmacological product is related, among other factors, to the water absorption capacity. For this reason, some authors advocate the use of excipients in the ointment that do not absorb water.11 The excipients of the ointment used in the present study are anhydrous and form water-in-oil emulsions in the presence of water, which can be absorbed.

Rodanant et al.16 did not find significant differences in pain and quality of life of patients whose suture removal was performed on the third or seventh day after extraction of impacted lower third molars. In the present study, the suture was removed on the seventh postoperative day, since it is believed that this period allows a more favorable alveolar repair, avoiding wound dehiscence.

Bacterial colonization in the suture may also be related to factors inherent to the patient, such as oral hygiene.17 In the present study, the oral hygiene of each patient was not analyzed in detail by the index of decayed, missing and filled teeth, being classified only as satisfactory and unsatisfactory, according to the dental biofilm, missing teeth and indication of extraction. All patients had unsatisfactory oral hygiene. Further studies are suggested to assess the correlation of other external factors, such as brushing habits and educational level, as well as to evaluate the bacterial colonization of sutures in patients with satisfactory oral hygiene that present indications for third molars extraction.

Despite the antiseptic composition of the ointment, it is noted that its association, both with silk and nylon sutures, did not reduce the bacterial adhesion on its surfaces.

1. Silverstein LH, Kurtzman GM, Kurtzman D. Suturing for optimal soft tissue management. Gen Dent. 2007;55(2):95-100. 2. Asher R, Chacartchi T, Tandlich M, Shapira L, Polak D. Microbial accumulation on different suture materials following oral surgery: a randomized controlled study. Clin Oral Investig. 2019 Feb;23(2):559-65. 3. Otten JE, Wiedmann-Al-Ahmad M, Jahnke H,

Pelz K. Bacterial colonization on different suture materials-a potential risk for intraoral dentoalveolar surgery. J Biomed Mater Res B Appl Biomater. 2005

Jul;74(1):627-35. 4. Dhom J, Bloes DA, Peschel A, Hofmann UK. Bacterial adhesion to suture material in a contaminated wound model: Comparison of monofilament, braided, and barbed sutures. J Orthop Res. 2017

Apr;35(4):925-33. 5. Faria RL, Cardoso LML, Akisue G, Pereira CA, Junqueira JC, Jorge AOC, et al. Antimicrobial activity of

Calendula officinalis, Camellia sinensis and chlorhexidine against the adherence of microorganisms to sutures after extraction of unerupted third molars.

J Appl Oral Sci. 2011 Oct;19(5):476-82. 6. Gupta SJ, Tevatia S, Khatri V, Dodwad V. Comparative evaluation of antiseptic pomade to prevent bacterial colonization after periodontal flap surgery — a clinical & microbiological study. J Dent Specialities. 2017;5(2):102-7. 7. Cruz F, Leite F, Cruz G. Sutures coated with antiseptic pomade to prevent bacterial colonization: a randomized clinical trial. Oral Surg Oral Med Oral

Pathol Oral Radiol. 2013 Aug; 116(2):e103-9. 8. Cruz M. Long-term assay of iodoform pomade in the bacterial control of the inner ambient of dental implants: a randomized clinical trial. Clin Int J Oral

Science. 2002;15(1):1-13. 9. Cosola S, Giammarinaro E, Marconcini S, Lelli M,

Lorenzi C, Genovesi AM. Prevention of bacterial colonization on suture threads after oral surgery: comparison between propolis- and chlorhexidinebased formulae. J Biol Regul Homeost Agents. 2019;33(4):1275-81. 10. Arteagoitia I, Andrés CR, Ramos E. Does chlorhexidine reduce bacteremia following tooth extraction?

A systematic review and meta-analysis. PLoS One. 2018; 13(4): e0195592. 11. Larsen PE. The effect of a chlorhexidine rinse on the incidence of alveolar osteitis following the surgical removal of impacted mandibular third molars. J Oral

Maxillofac Surg. 1991 Sep;49(9):932-7. 12. Ugwumba CU, Adeyemo WL, Odeniyi OM, Arotiba GT, Ogunsola FT. Preoperative administration of 0.2% chlorhexidine mouthrinse reduces the risk of bacteraemia associated with intra-alveolar tooth extraction. J Craniomaxillofac Surg. 2014

Dec;42(8):1783-8. 13. Mahesh L, Kumar VR, Jain A, Shukla S, Aragoneses JM,

González JM, et al. Bacterial adherence around sutures of different material at grafted site: a microbiological analysis. Materials (Basel) 2019;12(18):1-8. 14. Koyuncuoglu CK, Yaman D, Kasnak G, Demirel K.

Preference of suture specifications in a selected periodontal and implant surgeries in Turkey. Eur J Dent. 2019;13(1):108-13. 15. Silva Junior JA, Wassall T, Ramalho SA, Brito Junior RB. Evaluation of the tecidual reply to an iodoform folder applied in the internal chamber of ossentegration settings in vivo. RGO. 2006 Mar;54(1):21-6. 16. Rodanant P, Wattanajitseree K, Shrestha B, Wongsirichat N. Pain and quality of life related to suture removal after 3 or 7 days at the extraction sites of impacted lower third molars. J Dent Anesth Pain Med. 2016

Jun;16(2):131-6. 17. Bucci M, Borgonovo A, Bianchi A, Zanellato A, Re D.

Microbiological analysis of bacterial plaque on three different threads in oral surgery. Minerva Stomatol. 2017 Feb;66(1):28-34.