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Disinfection of Implant Prosthetic Components Before Delivery
Fawad Javed1, Rafael Delgado-Ruiz2, and Georgios E. Romanos3
1 Department of Orthodontics and Dentofacial Orthopedics, Eastman Institute for Oral Health, University of Rochester, Rochester, NY, USA
2 Department of Prosthodontics and Digital Technology, Stony Brook University, Stony Brook, NY, USA
3 Department of Periodontics and Endodontics, School of Dental Medicine, Stony Brook University, Stony Brook, NY, USA
Background
The subgingival oral biofilm is generally criticized for the initiation and progression of peri‐implant diseases, peri‐implant mucositis, and peri‐implantitis [1]. The oral biofilm harbors pathogenic bacteria such as Aggregatibacter actinomycetemcomitans (A. actinomycetemcomitans), Prevotella intermedia (P. intermedia), and Porphyromonas gingivalis (P. gingivalis) that have been directly related with the etiopathogenesis and prognosis of peri‐implant diseases [2–5]. Local and systemic risk factors that are commonly associated with the increased colonization of pathogenic bacteria around implants include poor oral hygiene status and tobacco‐smoking and poorly controlled diabetes mellitus, respectively [6–8]. However, handling of implant prosthetic components by staff and laboratory personnel can also increase the risk of microbial contamination [9, 10]. A major challenge in two‐phase implant treatment (delayed loaded implants) is the risk of microbial leakage at the implant–abutment connection (IAC) due to the presence of microgaps [11, 12]. An increased bacterial colonization has also been identified on customized titanium abutments [9]. Biologically, molecules such as toxins and constituents of bacterial wall are accountable for peri‐implant inflammatory reactions. These molecules (endotoxins) penetrate the microgaps at the IAC instead of the whole bacterial cell and enhance an inflammatory response and jeopardize the surrounding bone [13, 14]. Moreover, the extent of bacterial contamination at the IAC depends on the accuracy of fit between the fixture and the abutment, tightening torque and micro‐movements between the connected components during chewing. This is concerning as presence of pathogenic bacteria at the IAC increases the risk of future peri‐implant soft tissue inflammation and crestal bone loss (CBL) even in individuals stringently following routine oral hygiene maintenance protocols such as toothbrushing and flossing of interproximal spaces. It has also been proposed that complete removal of contaminants and pollutants from implant abutments improves the preload maintenance of the screw/abutment complex [15].
Objective
This chapter aims to provide an evidence‐based review of methods that are used to disinfect implant abutments before insertion.
Literature Search Strategy
Indexed databases namely PubMed/Medline, Google Scholar, and ISI Web of Knowledge were searched without time and language barriers to identify studies that assessed methods of disinfection of implant abutments before delivery. The pattern of this chapter was customized to mainly summarize the relevant information.
Methods of Implant Abutment Disinfection
Argon Plasma
Mixtures of gases such as argon (Ar) and oxygen are metastable rare gases that carry significant amounts of energy; and lead to the formation of reactive oxygen species (ROS) via energy transfer reactions. The final manufacturing process of Titanium implants involves treatment with argon plasma (AP) prior to sterilization by gamma rays. In this technique, electronic mantle of materials is activated by a spray of argon under room temperature and pressure. This procedure helps remove contamination and microbiologic pollution from metal surfaces. Simultaneously, AP also helps modify the physico‐chemical, and biological features of implant surfaces, and their ability to adapt with the surrounding soft and osseous tissues [16–18]. In vitro studies [19, 20] have assessed the effect of AP on different implant surfaces with reference to adhesion of osteoblasts, fibroblasts, and microbial decontamination. The scanning electron microscopy results showed that AP reduces bacterial adhesion to implant discs and promotes spreading and attachment of fibroblasts and osteoblasts [19, 20]. In an experimental study on canine‐models, Coelho et al. [18] assessed the effect of AP applications immediately prior to dental implant placement on peri‐implant bone. Histomorphometric examinations performed at three weeks showed a significantly higher bone‐to‐implant contact percentage (>300%) and mean bone area fraction occupancy (>30%) in AP‐treated implant surfaces compared with controls (untreated surfaces) [18]. In a randomized controlled trial (RCT), Canullo et al. [21] investigated radiographic osseous changes around customized, platform‐switched abutments placed according to the “one‐abutment‐one‐time” protocol, with (test‐group) and without (control‐group) PA cleaning treatment in 30 patients with a history of periodontal disease and thin gingival phenotype (<1 mm). Patients were randomly divided into test and control groups immediately before abutment connection. In the control group, cleaning protocol comprised steaming. Outcome measures were: (i) implant and prosthesis success rate; (ii) prosthetic and biological complications; (iii) CBL; (iv) esthetic and periodontal parameters; and (v) patient satisfaction [21]. At five‐years’ follow‐up, none of the implants in either group were lost; however, CBL was significantly higher in the control than the test group. Periodontal parameters were stable in both groups at 60 months of follow‐up. This study [21] concluded that AP treatment is a useful technique for disinfection of implant abutments before connection. This study was basically a long‐term (5‐years follow‐up) of an interim RCT, which was followed up for 24 months [22]. Outcomes of this interim study [22] were also similar with those reported in the five‐year follow‐up RCT [21], that is, disinfection of implant abutments using AP removes bacteria and minimizes the risk of CBL to a much greater extent compared with steam disinfection (SD). It is known that a history of periodontitis is a risk factor for peri‐implant diseases including peri‐implantitis [23–25]. In this context, the risk of future peri‐implantitis is higher in these patients in case traditional methods, such as SD are used to decontaminate implant abutments before delivery. Therefore, abutment disinfection using AP is a reliable strategy to minimize bacterial colonization and leakage of their biproducts at the IAC. This may help facilitate long‐term success and survival of dental implants. An overview of studies, which assessed the role of AP in abutment disinfection is presented in Table 21.1.
Table 21.1 An overview of studies, which assessed the role of AP in abutment disinfection.
| Authors et al. | Study design | Groups | Follow‐up | Outcomes |
|---|---|---|---|---|
| Canullo et al. [19] | In vitro | Test‐group: AP treatment on implant discs Control group: No treatment |
NA | AP causes bacterial decontamination and increases osteoblastic attachment. |
| Canullo et al. [20] | In vitro | Test‐group: AP treatment on implant discs Control group: No treatment |
NA | AP increases fibroblast attachment to implant discs |
| Canullo et al. [21] | RCT | Test group: Abutments cleaned with AP Control group: Abutments cleaned with steam disinfection |
5 years | AP is more effective in decontaminating implant abutments than steam disinfection |
| Canullo et al. [22] | RCT | Test group: Abutments cleaned with AP Control group: Abutments cleaned with steam disinfection |
2 years | AP is more effective in decontaminating implant abutments than steam disinfection. |
AP, Argon plasma; NA, Not applicable; RCT, Randomized controlled trial.
Chlorhexidine
In a double blinded RCT [26], investigators applied 0.2% chlorhexidine (CHX) gel (16 patients) or a placebo gel (n = 16 patients) to the IAC during all surgical and prosthetic phases and assessed the effect on CBL for up to one year. The one‐year follow‐up results showed a significantly higher CBL around implants treated with the placebo gel compared with those in which, 0.2% CHX as applied at the IAC [26]. However, implants in both groups showed minimal peri‐implant plaque and gingival bleeding scores at one‐year of follow‐up. This study [26] concluded that application of 0.2% CHX gel at the IAC minimizes the risk of CBL for up to 12 months. One limitation of this study is that microbiological assessment of subgingival oral biofilm samples and immunological investigations (for instance, assessment of destructive inflammatory cytokines such as tumor necrosis factor‐alpha and interleukin 1‐beta in the peri‐implant sulcular fluid [PISF]) were not performed. It is tempting to speculate that application of 0.2% CHX gel to the IAC during all surgical and prosthetic phases reduces the counts of pathogenic bacteria (such as A. actinomycetemcomitans, P. gingivalis, and P. intermedia) in the subgingival oral biofilm; and reduces the expression of proinflammatory cytokines in the PISF thereby contributing toward the maintenance of peri‐implant health. Another double‐blinded RCT [27] quantitative investigated, the presence of P. gingivalis on the healing abutment when 0.20% CHX gel or a placebo gel were applied during the first and second implant surgical stages. Besides recording peri‐implant plaque and gingival bleeding scores, inflammatory infiltrate and the micro‐vessel density surrounding peri‐implant soft tissues were also assessed at three‐four points (at the time of implant insertion, second stage surgery, prosthetic phase, and 12 months of follow‐up). At one‐year follow‐up, all implants showed low scores of plaque and gingival bleeding; however, a significantly low count of P. gingivalis was observed in healing abutments belonging to the 0.2% CHX group compared with the placebo group [27]. Moreover, the placebo group demonstrated the highest expression of inflammation markers for B‐lymphocytes, T‐lymphocytes, and macrophages cluster definitions (CD) (CD3, CD20, and CD68). Thus, use of 0.2% CHX is most likely a reliable treatment option in clinical implant dentistry as it significantly reduces P. gingivalis counts and host inflammatory response around implant abutments. However, in a recent in vitro study [28], antibacterial efficacy of 0.2% CHX was compared with 0.8% hyaluronic acid (HA) against P. gingivalis strains. The experimental results showed that 0.8% HA is a more potent antibacterial agent against P. gingivalis strains compared with 0.2% CHX [28]. By no means should this result tempt readers to perceive that 0.2% CHX is inferior to other pharmacologic preparations in terms of its antibacterial efficacy as there was a marked difference in the concentrations of both tested preparations. There is a possibility that 0.2% CHX gel is as effective as 0.2% HA in demonstrating antibacterial actions against P. gingivalis strains; however, an in vitro study reported that 0.2% CHX has no effect on bacterial endotoxin that possesses the ability to invade the IAC [29]. With regards to CHX rinsing, results from a clinical study [10] on 10 patients showed that CHX rinsing does not have any effect toward decontamination at IAC. The study showed presence of bacteria (incl. anaerobic species) after a continuous irrigation (for 3 mm) within the butt‐joint connections after the use of CHX. However, results of a six‐months follow‐up RCT [30] showed that 0.1% CHX gel displays antibacterial activity against a variety of microbes including P. intermedia, A. actinomycetemcomitans, P. gingivalis, Fusobacterium nucleatum, and Treponema denticola. In summary, the antibacterial effectiveness of CHX at the IAC remains debatable predominantly due to limited clinical evidence. Moreover, it remains to be determined what concentration (0.1%, 0.2%, or another concentration) is most relevant in terms of minimizing the risk of bacterial contamination at the IAC immediately after prosthetic loading (Table 21.2).
Nanoparticles
Nanostructures or nanoparticles are derived from a variety of metals such as copper and zinc [32]. Studies have shown that nanoparticles possess unique physiochemical properties [33]
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