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Dr Andrew Osafo BDS Dip Sed FIADFE

Dr Andrew Osafo
Primary and secondary care dentist

Dr Andrew Osafo BDS Dip Sed FIADFE talks about the benefits that silver diamine fluoride can bring to treating hypersensitivity and the growing evidence supporting its potential for caries control

As a dentist with a special interest in paediatric dentistry and minimally invasive dentistry you have become very involved with SDF treatment. Can you explain more about SDF and in which clinical situations it is most effective?
Silver diamine fluoride (SDF) is a solution of silver, fluoride and ammonium ions, the ammonia acting as a stabilising agent for the solution. It is well known that silver is a powerful antimicrobial agent and has been used extensively and recorded in history for a variety of medicinal purposes. It has been used in dentistry for more than a century for caries management and to prevent further demineralisation of tooth surfaces along with fluoride that has a bacteriostatic effect and aids in remineralisation. This makes SDF effective not just as a desensitising agent but also as a caries inhibitor [1].

There are only two CE marked SDF products licenced to treat hypersensitivity in the UK – SDI Riva Star and Riva Star Aqua. What makes them so effective?
These materials work so effectively as they block the open dental tubules which are the result of dentine hypersensitivity. The difference between the two products is that with Riva Star the carrier solution is ammonium and with Riva Star Aqua the carrier solution is water.

Why are these products being used off-label to treat caries?
Although these materials are not licenced for caries arrest in the UK, they can be used off-label by licenced professionals when judged by the prescriber to be in the best interest of the patient, on the basis of the available evidence. This is a parallel situation to fluoride varnish, which has the same device clearance but is ubiquitously used off-label by dentists and physicians as an agent to prevent caries [4].

There is a large body of evidence, especially in the last few years, that show that SDF is a very safe and effective intervention for caries arrest and prevention including numerous in vitro and in vivo studies and randomly controlled trials. One example is a ground-breaking paper released in 2019 that said: “38% SDF applied biannually is effective for arresting advanced cavitated carious lesions on any coronal surface (moderate to high certainty)” [2,3].

Which patients benefit most from SDF treatment?
It’s ideal in an emergency care situation for triaging emergencies. It is also very effective in arresting carious lesions in adults and children who have a high caries risk, those with progressing carious lesions and those unable to tolerate invasive treatments. SDF has been referred to in a critical review as a “caries Silver-Fluoride bullet” for arresting and preventing caries.

It is particularly beneficial for children and elderly patients but also in cases where you have a deep cavity. It can also work also synergistically with glass ionomer in the SMART technique.

Can you explain more about the SMART technique?
It is about caries identification and looking at partial caries removal over complete excavation. The aim is to selectively remove the infected dentine and then treat the remaining affected dentine with either silver diamine fluoride or silver fluoride to seal off the bacterial source and cut off its nutrient supply. Then glass ionomer is applied, effectively arresting the caries without removing additional tooth structure. Hence the term SMART – silver modified atraumatic restorative technique.

Are there any contraindications for the use of SDF?
A careful assessment of the patient is needed before SDF treatment [5].

Contraindications include:

  • Patients with known allergies to silver, fluoride or ammonia
  • Clinical signs or symptoms of irreversible pulpitis or dental abscess/fistula
  • Radiographic signs of pulpal involvement or peri-radicular pathology
  • Infection or pain from pulp or food packing
  • If there are any painful sores or raw areas on the gums (i.e. ulcerative gingivitis) or anywhere in the mouth (i.e. stomatitis)
  • SDF/KI is contraindicated in pregnant women and during the first six months of breastfeeding due to concern of overloading the developing thyroid with iodine

It is also very important to inform patients about the possibility of staining, especially if you’re working in the anterior region. A known problem with SDF is when free silver ions react with the silver sulphides to cause black staining of the treated tooth. What is special about Riva Star and Riva Star Aqua is their patented, two-step procedure that minimises the risk of staining. By applying an immediate application of potassium iodide (KI) over the silver fluoride, a silver precipitate is formed, which then turns clear, effectively reducing the chance of discoloration.

How cost-effective is SDF treatment?
It is very cost-effective, particularly in groups at higher caries risk such as older patients, children, dementia patients and again, whenever it is in the best interest of the patient. The cost versus the benefits far outweigh any cost of the materials.

Are there any advantages to using Riva Star Aqua compared to Riva Star?
Riva Star Aqua is referred to as the ‘next generation’ of silver diamine fluoride treatment. Because it doesn’t contain ammonia, which causes the pH to drop, there is less risk of tissue irritation, it doesn’t have an unpleasant taste or smell and there is no need to refrigerate the material.

However, despite the slightly different compositions between Riva Star and Riva Star Aqua, studies have shown they deliver the same effects in terms of caries arrest so I would say it’s up to the individual dentist to decide which they prefer.

SDF is now recommended for routine practice for the prevention and treatment of dental caries by the World Health Organisation (WHO) and Global Oral Health Policies and Practice Guidelines worldwide. What are your conclusions about this?
In 2021 the WHO added silver diamine fluoride and glass ionomer cement to its list of Essential Medicines for both adults and children for the prevention and treatment of dental caries worldwide [6], which is a very significant endorsement indeed.

SDF is also recommended for use by organisations including the American Dental Association and the British Society of Paediatric Dentistry as well as the Chief Dental Officer. We are encouraged as registrants to keep up with the evidence and the evidence is clearly there to show that silver diamine fluoride and silver fluoride are very effective and safe interventions for caries arrest and prevention in children and adults, as well as in the treatment of dentine hypersensitivity.

The evidence clearly shows that SDF is a major benefit to our patients. As we know, tooth decay remains the number one reason for hospital admission for children [7], so if we can do anything to reduce the caries burden on health services, we really should be looking at the evidence before us.

For more information about SDI Riva Star and Riva Star Aqua’s clinical applications, call 07970 156 178 or email [email protected].


References and recommended reading:

  1. Recommended reading: Greenwall-Cohen, J., Greenwall, L. & Barry, S. Silver diamine fluoride – an overview of the literature and current clinical techniques. Br Dent J 2020 228(11):831-838.
  2. Urquhart O, Tampi MP, Pilcher L, Slayton RL, Araujo MWB, Fontana M, Guzmán-Armstrong S, Nascimento MM, Nový BB, Tinanoff N, Weyant RJ, Wolff MS, Young DA, Zero DT, Brignardello-Petersen R, Banfield L, Parikh A, Joshi G, Carrasco-Labra A. Nonrestorative Treatments for Caries: Systematic Review and Network Meta-analysis. J Dent Res. 2019 98(1), 14–26
  3. Recommended reading: Trieu, Alice; Mohamed, Ahmed; Lynch, Edward. Silver diamine fluoride versus sodium fluoride for arresting dentine caries in children: a systematic review and meta-analysis. Sci Rep. 2019;9(1):2115. Seifo, N., Robertson, M.D., Maclean, J.H., Blain, K.M., Grosse, S., Milne, R.R., Seeballuck, C., & Innes, N.P. The use of silver diamine fluoride (SDF) in dental practice. Br Dent J. 2020;228(2):75‐ 81.
  4. Rosenblatt A, Stamford T C, Niederman R. Silver diamine fluoride: a caries “silver-fluoride bullet”. J Dent Res 2009; 88: 116–125.
  5. Horst, Jeremy A. et al. UCSF Protocol for Caries Arrest Using Silver Diamine Fluoride: Rationale, Indications, and Consent ( J Calif Dent Assoc 2016; 44: 16–28.)
  6. Executive summary. The Selection and Use of Essential Medicines 2021 Report of the 23rd WHO Expert Committee on the Selection and Use of Essential Medicines (