Management of Your Dental Unit Water Lines “DUWL”s.

Normal maintenance and operation of our DUWLs dictate that we utilize daily cleaner/flushing solutions in our DUWL bottles in order to help reduce the total CFU count and biofilm that exits from the dental tubing connected to our Handpieces, Tri-syringes and Cavitrons / EMS units. Unfortunately, NONE of these solutions offer any sort of true Disinfectant or Antimicrobial capability – NONE.  At best they provide bacteriostatic benefit. These solutions are either all surfactant based or enzyme based solutions with tiny amounts of added hydrogen peroxide which (by itself) is woefully inadequate at killing pathogenic bacteria, viruses and polymicrobial biofilms. Besides, you cannot blend Disinfectant class chemicals with enzymes, for inanimate surface disinfection, because these disinfectant chemicals will denature the enzymes! I have heard through some blogs that Dentists are suggesting that we simply add Chlorhexidine Di Gluconate (“CHG”) to the water bottle (because we are taught that CHG is a general purpose disinfectant which is safe for internal / oral use). There are several serious shortcomings with this approach including; 

  1. CHG is now classified here in BC as a schedule 1 drug – so unless Dentists are prepared to have detailed conversations with our patients (before you even pick up the handpiece or the ultrasonic scaler) about All Reasonable Tx Options / All Costs / Risks /Benefits and Choice of Materials and give the patient the Option for No Tx and then verbally prescribe the use of CHG to the Hygienist for each patient and then review in detail an informed consent and then make detailed patient notes in their chart – you cannot use CHG in any capacity – least of all as a chemotoxic antimicrobial (drug) additive to the DUWLs. 

See below information circular from CDSBC:

Interpretive Guidance for Dentist-prescribing of Schedule I Drugs (including epinephrine and chlorhexidine) for Administration by a Dental Hygienist The following interpretive guidance from the College of Dental Hygienists of BC and the College of Dental Surgeons of BC is applicable to both the dental office setting – whether or not the dentist is on site – and to private dental hygiene practice.​On February 24, 2020, the Ministry of Health announced amendments to the regulations (scope of practice statements) for dental hygienists, dental technicians, denturists and dentists. Two of the changes that affect the provision of dental hygiene services are:Dental hygienists with the proper certification can now administer local anaesthetic without a dentist on site. The College of Dental Hygienists of BC indicates this certification with the letter “C” on a dental hygienist’s registration.Dental hygienists wishing to administer a Schedule I drug (e.g. local anaesthetic containing epinephrine or chlorhexidine), must ensure the patient has a prescription from a dentist, authorizing the dispensing of the Schedule I drug.​Local anaesthetics without epinephrine are not Schedule I drugs and do not require a prescription.​​​​​In response to the amended regulations, CDSBC is continuing to work with the other oral health colleges to develop guidance for registrants. CDSBC will be updating the professional standard document Prescribing and Dispensing Drugs in the near future.​ It is expected the decision to administer a Schedule I drug will be based on collaborative discussion and decision-making amongst the patient, dental hygienist and dentist and include thorough documentation of those discussions and decisions, including the authorization by the dentist to dispense the drug. ​In order for a patient to provide informed consent for the administration of a Schedule I drug, it is expected that patient will be made aware of all of the risks, benefits, associated costs and options (including not administering the drug). In the case of anaesthetic containing a vasoconstrictor, this would include a discussion that while this formulation increases the depth and duration of anaesthesia, it may impact cardiac function. The dental hygienist and dentist must be satisfied that, following a thorough clinical assessment and review of the medical history, there are no contraindications to the administration of the Schedule I drug.​ A prescription can be defined as an authorization for the dispensing of a drug to a patient and may be written or verbal. Within the traditional model of a dental hygienist and dentist working collaboratively within the same office, the specific requirement in the amended regulations of a prescription prior to administration of a Schedule I drug by a dental hygienist is not expected to change existing protocols. Rather, it will serve to focus the entire dental team on the existing standards of collaborative care, including a complete pre-treatment assessment of the patient, reviewing and updating of the patient’s medical history and a determination through discussion between the dental hygienist and dentist of the need for the administration of the drug for the patient. Once a need is determined, the dentist can provide a verbal authorization for the drug to be dispensed to the patient and the dental hygienist can proceed with the administration, regardless of whether the dentist is on site or not. In the case of a private dental hygiene practice, the authorization can be provided by a written prescription from the dentist for the patient or over the phone following the expected standards of collaborative care including assessment, review, and thorough discussion between the dental hygienist and the dentist. A dentist may choose to make a standing order prescription for a given patient to cover a specific time frame (e.g. three to six months). If this is the case, it is expected the hygienist will review, update and document the patient’s medical status as well as revisit and determine the ongoing need for the drug before each subsequent administration, engaging the prescribing dentist in discussion should any changes be noted.​ It is expected the patient record will include:The name and concentration (dosage) of the Schedule I drug being prescribed and administered.The reason and/or rationale for the need to prescribe and administer the drug.Documentation in the chart of the verbal prescription, along with the prescribing dentist’s signature. If the dentist provides a prescription by phone, the dental hygienist must document this in the patient record and sign it. If the dentist has provided a written prescription for the patient, a copy must be included in the patient’s record.Documentation as to the patient’s provision of informed consent for the administration of the Schedule I drug.

b)  The latest peer reviewed literature shows that the use of CHG actually negatively impacts interfacial bond strengths to dentine – rather than improving them by eliminating Metallo Matrix Proteinases (“MMPs”). There are literally dozens of Antibiotics that can also remove MMPs – this is not something that is exclusive only to CHG.  

c) CHG is a non-specific chemotoxic drug which attacks both Pathogenic AND Probiotic bacteria upsetting the oral microbiome which can lead to oral candidiasis. It is also irritating to the tissue and stains the teeth.

d). CHG has very limited efficacy against certain anaerobic gram negative cocci such as Viellionella commonly found in the oral cavity.

e) Antibiotic Resistance to CHG usually arises through the expression of drug efflux proteins that can pump out CHG such as QacA/QacB from S. aureus and the MexAB-OprM system from P. aeruginosa [Kampf G et al 2016, J.Hosp. Infect.94,213-227] This also poses the question as to the possible relationship between CHG tolerance and Antibiotic Resistance. Very recently, links between the use of CHG and resistance to both vancomycin and the last line antibiotic, Colistin, have been established. [Wand ME,Bock L et al 2016, Mechanisms of increased resistance to CHG and cross resistance to Colistin. Antimicrob. Agents Chemother. 60, e01162-e01216,101] These worrying observations clearly indicate that in addition to antibiotic stewardship we also need stewardship of our biocides especially the critically useful ones such as CHG.

The use of other Hospital Grade Disinfectant solutions in the DUWL is NOT POSSIBLE because of the known cytotoxic effects associated with chemicals such as Accelerated Hydrogen Peroxide, Glutaraldehydes, Tri-chlorinated Phenolics, Sodium Didecyl Methyl Amonnium Chlorides / Sulfates – ALL of which require the use of PPE before handling.

So, to help reduce the bacterial and viral bio-burden from patients saliva and mucous secretions (that are potenitally infected with Covid 19) which are going to mix with the contents of the Waterline in the mouth and result in aerosolized particles, WHY NOT utilize a proven Antimcrobial, Wound Healing agent as a DUWL Cleaner? – The OraSIL product has proven broad spectrum efficacy against many pathogenic microorganisms including, Hep, B, MRSA, VRE, CRE, SARS, Bacillus anthracis, Candida as well as pathogenic bacteria including all 8 aggressive strains of MDR Acinetobacter baumannii and Leishmania Promastigotes – (flesh eating bacteria).

This would help to effectively kill any pathogenic microorganisms in the aerosolized liquids without harming the probiotic bacteria. Unless someone else can suggest an alternative, pragmatic solution to this problem – one that already has Cdn NPN approval for use in surgical applications as an “Antimicrobial Wound Wash Irrigant” and could easily be used by Dentists today (in an off label application) as a DUWL Cleaner?  NOTE: that Better than 75% of ALL Healthcare Professionals use medical products for off label uses – as a HCP you have that right so long as you can justify the products intended use and substantiate its safety, efficacy and performance. There is enough peer reviewed science, clinical documentation, regulatory clearances and Patents surrounding this technology to easily meet that minimum threshold.

I am asking for my dental peers help to spread the word about this science based Nanotechnology solution so that we can all get back to work and help our patients and our staff! 

There is only one commercially available alternative to Saline available in Canada as an antimicrobial surgical wound wash that is also capable of disinfecting a broad spectrum of pathogenic bacteria and viruses without harming the oral tissues while still acting as a wound healing agent. That product is called OraSIL Wound Wash Irrigant and the technology behind it is referred to as NanoMetallic Silver Tetrahedral Tetraoxide or “NMSTTO”. NMSTTO is a new product category with near ubiquitous applications in the Dental industry which was recently launched at the Vancouver PDC March 5-7, 2020 under the OraSIL, VeraSIL and CuraSIL brand names.

Efficacy and Performance: In 2017, the worlds largest Peer Reviewed Meta-Analysis on Silver Nanotechnology was published in Dental Materials magazine entitled:

“Silver NanoParticles in Dentistry – A review of 155 peer reviewed articles, Dental Materials, Volume 33, Issue 10, October 2017, Pages 1110-1126.”

In this Meta Analysis, Silver nanoparticles (AgNPs) were extensively studied for their antimicrobial properties, which provide an extensive applicability in dentistry. Because of this increasing interest in AgNPs, the objective of this paper was to review their use in nano-composites; implant coatings; pre-formulation with antimicrobial activity against cariogenic pathogens, periodontal biofilm, fungal pathogens and endodontic bacteria; and other applications such as treatment of oral cancer and local anesthesia. Recent achievements in the study of the mechanism of action and the most important toxicological aspects were also presented.

Meta Analysis Results. A total of 155 peer-reviewed articles were reviewed. Most of them were published in the period of 2012–2017, demonstrating that this topic currently represents an important trend in dentistry research. In vitro studies reveal the excellent antimicrobial activity of AgNPs when associated with dental materials such as nanocomposites, acrylic resins, resin co-monomers, adhesives, intracanal medication, and implant coatings. Moreover, AgNPs were demonstrated to be interesting tools in the treatment of oral cancers due to their antitumor properties.

Significance. The literature indicates that AgNPs are a promising system with important features such as antimicrobial, anti-inflammatory and anti-tumor activity, and a potential carrier in sustained drug delivery. Additionally, when NanoSilver is combined with the use of Oral Antibiotics the literature demonstrates improved bacterial clearance rates which means a lower risk of Antibiotic Resistance!

Safety: In the Bibleography of this Meta Analysis, there is a reference to the worlds largest human ingestion, absorption and inhalation study on Silver Nanoparticles which concluded that the Silver Nanoparticles were safe for human ingestion. These findings were also published in online in a 3 part PubMed report where blood, saliva, urine and the P450 Cytochrome A enzyme cascade were evaluated on human test subjects after oral ingestion of NanoSilver using MRI and CT imaging – all showing no negative side effects.

The bottom line is that some of our regulatory bodies are unaware of all the working antimicrobial solutions we Dentists have at our fingertips. They also know very little about the myriad of dental applications of Nanotechnology that are now commercially available. Case and Point: the VeraSIL Antiseptic Skin Cleanser and Protective Mask Spray which could dramatically improve the level of personal barrier protection when HCWs are forced to re-use an N95 Mask or a Level 2/3 Mask. Essentially, our BC Ministry of Health are making decisions for Dental Healthcare Professionals without ALL the material facts/solutions. This is severely impacting our ability to earn an income (for Dentists and Staff).

And IF ANYONE has an alternative solution that is; i) regulatory approved ii) commercially viable and iii) an effective science based solution (other than a) taking an forced ‘vacation’ for the next 2 or possibly 3 months or b) continuing to use mildly bacteriostatic enzymatic solutions in your DUWLs or c) utilizing an array of chemotoxic disinfectants that are unsafe for human ingestion and proven to contribute to Antibiotic Resistance, I would be very interested in hearing from you……

Don’t forget to check out the science! 


Posted by Dr Andrew Willoughby, General Dentist.