|
 
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| REVIEW ARTICLE |
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| Year : 2022 | Volume
: 14
| Issue : 1 | Page : 80-84 |
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Silver as an antimicrobial coating on titanium implants
Anukrati Katariya, Gouri Bhatia
Department of Periodontology, Teerthanker Mahaveer Dental College and Research Centre, Bagadpur, Uttar Pradesh, India
| Date of Submission | 11-May-2021 |
| Date of Acceptance | 10-Nov-2021 |
| Date of Web Publication | 04-Jan-2022 |
Correspondence Address:
Anukrati Katariya
Department of Periodontology, Teerthanker Mahaveer Dental College and Research Centre, Bagadpur, Uttar Pradesh
India
 Source of Support: None, Conflict of Interest: None  | Check |
DOI: 10.4103/jorr.jorr_33_21
Silver and its compounds have been used for centuries for their medicinal properties and for more than a century in dentistry. Biofilm formation and microbial colonization on the surface of implant devices may cause peri-implantitis, resistance to aggressive pharmacological agents as well as host defenses. Therefore, different surface treatments to improve the antibacterial activity of titanium implants have been created. Silver can be used to reduce bacterial adhesion to implant surfaces. The objective of this review is to depict the evidence supporting the medicinal use of silver in implant dentistry and their findings in clinical research.
Keywords: Antimicrobial, implant, surface modification
How to cite this article:
Katariya A, Bhatia G. Silver as an antimicrobial coating on titanium implants. J Oral Res Rev 2022;14:80-4 |
| Introduction | |  |
Factors such as surface chemistry and surface roughness of implants are necessary for good osseointegration of dental implants, and osseointegration has a very important role in the success or failure of implants.[1]
Dental implants are in constant exposure with the oral microbial flora attributing to partial contact between the bone and gingiva.[1] Adhesion of bacteria on the dental implant surfaces is the precondition for biofilm formation leading to the dental caries and periodontal diseases like peri-implantitis. Infections associated with dental implants may cause some extreme complications despite administering antimicrobial agents systemically in a clean environment.[2]
Bacterial biofilm is one of the important causes of bacterial infections around dental implants and antibiotics though have been in use in managing microbial infections, they are unable to eliminate this biofilm on its own. After the formation of biofilm on implant surface, this biofilm acts as a shield to protect the bacteria from anti-microbial substances like antibiotics. Furthermore, consuming unrestricted antibiotics not only encourages a rapid increase in the number of bacteria along with resistance to antibiotics, but also turns down the effectiveness of antibiotics. Hence, an efficacious modified implant surface in addition to antibacterial function is needed to forestall the adhesion of bacteria and biofilm formation.[3],[4],[5]
Numerous surface coatings of dental implants containing copper, zinc, fluoride, chlorhexidine, silver, and antibiotics such as amoxicillin, cephalothin, and gentamycin have been endeavored to provide with antibacterial properties.[6]
Silver ions or salts are well known to have a broad antimicrobial effect. For years, they are being used in different fields of medicine, including catheters, prosthesis, and wound dressings. Other than being a strong antimicrobial, silver has numerous advantages such as long-term antibacterial activity, low bacterial resistance, good biocompatibility among human cells, and low toxicity.[7]
| History | | |
The first medicinal but not antimicrobial use was recorded in around 750 AD. An early scientific paper given by Crede involved the use of silver in the management of inflammation of eyes (ophthalmia neonatorum) in newborn infants. Later, silver was recommended as an internal antiseptic.[8] Since 1800s, silver is being utilized in both medicine and dentistry for its antirheumatic, anticarious, and anti-microbial properties. Silver, in 1960s, combined with fluoride was advocated as a complex to reduce the prevalence of dental caries for a collective favorable outcome.[9]
| Antimicrobial Action Of Silver Ions | | |
Silver, generally used in silver nitrate form, is bactericidal or bacteriostatic, protozoacide, antifungal, and lethal to herpes simplex virus. However, cysts of Entamoeba histolytica, mycobacteria, and bacterial spores are not killed by silver. Various factors have an impact on the anti-microbial activity of silver salts. Silver has a tendency to assimilate to surfaces and the bactericidal activity is decreased in presence of chlorides, hard water, sulfides, and phosphates. The activity of silver increases with rise in temperature and is pH-dependent as it increases with increasing Ph. Along with many antimicrobial drugs, the title “general protoplasmic poison” was given to the activity of silver. Whilst it is correct that the protoplasm is in fact “poisoned,” there is much to learn as how this may occur.
The next discovery was the realization that silver was dynamically working in the bacterial cell with thiol (sulphydryl, SH) groups, whether they are structural or enzymic proteins. It was finally discovered that silver causes changes in the composition of the bacterial cell and interacts with nucleic acids. These characteristics are contemplated along with AgSD (Silver sulfadiazine).[8]
| Silver In Dental Practices | | |
Dental prosthesis
Silver particles have been incorporated into tissue conditioner, denture resins, and other biomaterials. Adding silver nanoparticles to resins for dentures and silicon-based liners have shown antifungal effect against Candida albicans.[10]
Periodontal microorganisms
Silver has shown antimicrobial activity against a wide range of dental plaque microorganisms, with adequate bacterial growth suppression even at low doses.[10]
In oral cancer
The anticancer capabilities of silver nanoparticles are a major reason for their usage in cancer therapy. This characteristic of silver nanoparticles has been linked to the production of oxidative stress, which leads to DNA damage and cell death. Dziedzic et al.[11] showed that low doses of AgNPs alone have anti-proliferative action against a tongue cancer squamous carcinoma cells in humans in an in vitro setting.
Endodontic infections
Silver particles are promising for endodontic treatment. Bahador et al.[12] in 2015 incorporated mineral trioxide aggregate (MTA) and showed better bacterial growth inhibition when compared to MTA alone.
| Silver Coated Titanium Implants | | |
Titanium implants, extensively used in dentistry, generally have infections around their surface and this remains one of the most significant complications in implantology. Several antibiotic coatings have been developed to prevent the infection around implant surfaces, although, majority of them present poor prolonged antibacterial action and also the chance of producing resistant strains after long-term use.[13],[14],[15] In this sense, the latest developments in silver chemistry have encouraged us to utilize such a metal ion as coating of implant surfaces. The main purpose is to alter the implant surfaces to create a safe, nontoxic, biocompatible surface that is protective against fungi and bacteria (as well as antibiotic-resistant bacteria). The traditional silver salts, in the studies, have not shown any satisfactory properties. Co-ordination polymers, that contain silver ions, have proved to be most promising for implant surface coating as they have (a) slight decomposition upon exposure to light, (b) low aqueous media solubility, and (c) high structural stability. The silver-coated surface layer of hydroxyapatite on the alumina substrate displays outstanding antibacterial properties against bacteria such as Staphylococcus aureus and Escherichia coli.[7] The silver-zeolite compound hinders the growth of anaerobic bacteria. Although the silver ions emitted from titanium implant surface contribute to its antibacterial activity, it has been shown that silver ions interfere with cell division by inactivating microorganisms, inducing stress in microorganisms, producing active oxygen, chromosomal aberrations, and DNA damage by structural changes to the cell membrane or cell wall.
| Advantages | | |
Today, again silver is chosen as an anti-microbial agent because of its broad-spectrum antimicrobial activity, its lack of widespread bacterial resistance, and its low toxicity. Silver compounds like silver sulphadiazine and silver nitrate have been in use as topical agent for treating infective skin lesions encountered in chronic ulcers and burns. Silver sulphadiazine, as a topical agent, has even become gold standard in treating burns.[16] Silver compounds are being used in dentistry since early 1840s. For example, utilization of silver nitrate to reduce caries incidence in the young dentition. Later, it was used as dentine desensitizer, as cavity sterilizing agent, and as prevention for caries in permanent molars. In 1960s, silver combined with fluoride was advocated as anticaries agent for a better-amalgamated effect. Silver fluoride may lead to black staining when associated with caries; therefore its clinical practice is limited.[17],[18]
| Biocompatibility And Adverse Effects | | |
Silver has proven to be biologically compatible substance for an extensive variety of medical devices. Although excessive amount of silver accumulates in kidney, spleen, liver, cornea, skin, nails, and gingival and mucosal membranes. When the body is exposed to a huge amount of silver compounds for longer period, it can cause permanent pigmentation of eye (argyrosis) and skin (argyria), when subjected to light. Argyria can be defined as a process that detoxifies silver by separating it in the tissue to turn into form of silver sulfide or complex of silver with protein. Signs of consuming low doses of silver compounds for a longer period include changes in blood cells and fatty degeneration of kidneys and liver. Despite the fact that silver does gets collected in some tissues and organs in the body, very limited evidence available specifies the plausible aftermath. A small number of familiar studies have shown an allergy to silver compounds. Few reports have indicated lenient yet brief raise of gingival redness around the tooth, or else a minute white lesion appears in oral mucosa that disappears generally within 48 h without any treatment. While using silver compounds, clinically, white changes in the mucosa or tissue ulcerations are of major concern as, although, these effects adverse effects are transient and mild, they outweigh the benefits of caries prevention. The evident drawback of silver compound, in dentistry, is the black staining that occurs when the ionized silver gets oxidized into metallic form of silver. The disadvantage of silver compound limits its clinical use wherever esthetics is concerned. The application of potassium iodide after applying silver compound has proven to reduce the staining effect. Although the silver iodide is considered sensitive to light and might turn black or brown on exposure.[9]
| Conclusion | | |
Prevention is safer and it is even more important than treatment for infections associated with implants. The features of biofilm formation involve a more uniform release of antibiotics from implant coatings. An antibacterial implant coating increases the growth and adhesion of host cells, thus preventing the development of bacterial adhesion and biofilm; hence, the “race to surface” can be won by the host cells. Silver-coated implant surfaces are water-soluble along with a fine antimicrobial action on the formation of bacterial biofilm. The progression of the microbial colonies round dental implants can be retarded by coating silver on titanium dental implants.
Financial support and sponsorship
Nil.
Conflicts of interest
There are no conflicts of interest.
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