Advantages of a Disclosing Agent

by Dr. Neha Dixit

Neha Dixit Portrait

Biofilm forms every day in our mouths as a result of eating food. Its soft, sticky consistency enables it to hide in hard to reach areas especially below the gum line, in pits fissures, around restorative or orthodontic appliances etc. If left there, the bacteria produce acid, which can erode tooth enamel and cause tooth decay and subsequent cavitation. Certain species can also affect and cause periodontal and peri implant diseases disease. Either of these primary diseases could lead to eventual tooth loss.

Removing biofilm, that builds up on teeth, daily is crucial in preventing dental disease. However there are areas which one cannot access during routine tooth brushing or areas which may be missed out. Hence it is important to be able to know, visualize and then clean. Because biofilm is not completely visible or virtually invisible to the naked eye, it's hard to tell if you've successfully removed it.1

That's where disclosing agents can help. A disclosing agent gives you a snapshot of where you need to improve your oral hygiene.

What is a disclosing agent? 2

A material which when applied on natural teeth makes biofilm visible, focusing on areas that have been missed out during daily toothbrushing.

Importance of using a disclosing agent has completely been neglected today specially amongst dental students.3

History of disclosing agents4

Skinner5 used the first disclosing solution i.e, iodine to teach oral hygiene and recommended the use of a disclosing solution to ensure that all "foreign substance" was removed, long before Loe et al.6 and Axelsson & Lindhe7 confirmed in their studies that there is a strong positive correlation between the presence of dental plaque and both caries and gingivitis.

Berwick8 introduced a dye that was the combination of brilliant green and crystal violet ,followed by Easlick9 who used bismark brown 7 and Raybin10 used gention violet and proved the advantages of non iodine dye. Soon after Skinner’s iodine was superceded by organic dye solutions because of the objectionable features of iodine solutions.

Amim et al.11 had been most instrumental in popularising the use of disclosing agents and introduced the use of F. D. & C Red #3 (Erythrosin) dye and like Raybin maintained that disclosing agents were bound to transform the home care regimen.

Heffemen12 and his colleagues noted that plaque, calculus and stains were more apparent under ultra-violet illumination, and the following year, Lang et al.13 examined the applicability of a fluorescent disclosing agent used with the Plaklite®. In the same year Block et al.14 developed a two tone dye test which stained more mature plaque blue (F. D. & C. Green #3 and newly formed plaque red (F. D. & C. Red #3) thus providing a "colour guide' as to the age of the plaque.

How does it work?15

  • Disclosing agents work by changing the colour of dental biofilm in order to provide a contrast with the tooth surface.
  • Biofilms have the capacity to retain large no. of dye substances due to the interaction. The polarity difference between the components of the dye and biofilm. Electrostatic interactions (proteins) and hydrogen bonds (polysaccharides) bind the particles together.
  • Surfaces which are biofilm free can easily be rinsed off.

What are the basic properties of an disclosing agent?

  • Compatible in taste
  • Easy to use
  • Good flavour
  • Intensity of colour: Providing good contrast between early and mature biofilm
  • Duration of intensity
  • Should encourage patient co-operation and comfort
  • Should come out easily during procedure
  • Not irritating to the gingiva, non-allergic
  • Water soluble and biocompatible

Dyes commonly used as disclosing agents16

Iodine, Mercurochrome, Bismark brown,Merbromin, Erythrosine, fast green, Fluorescein, two tone, basic fuchsin and three tone gel.

Two tone: essentially stains early biofilm which is less than 3 days old with reddish pink and mature biofilm which is more than 3 days old with a blue colour.

Three tone:  used for teenagers and adolescence specially with high risk of dental caries. Besides staining the early and mature biofilm, it also discloses biofilm which is acidogenic and with a ph of less than 4.5.

Types of disclosing agents:

Disclosing agents are available in many different forms:

  1. Tablets: used a lot in the past, however they have a big disadvantage of being difficult to chew and colours the entire mouth including the tongue and cheeks mucosa. Besides using tablets was time consuming and patient dependent. Some patients did not chew well or enough as a result of which was inadequate biofilm disclosure.
  2. Mouthrinses: used till date , however they colour the entire mouth. In addition one needed an additional glass to rinse it out or landed up in dirty spittoons.
  3. Concentrated liquids: these needed to be applied using a special pellet and a dapen dish hence not only increasing the cost but also added to a lot of waste and consumed time for the clinician. Also available were long ear bud type disclosing solutions, which soaked up a lot of material , hence having the clinician to at times uses a couple to efficiently disclose the entire mouth. With all the above the fear of the patient messing up his or her clothes was very high as a result of which, use of a disclosing agent was decreasing in popularity.
  4. Pre Loaded Pellets: Modern approach to disclosing. Easy to use with a pair of tweezers. Will colour only areas where the pellet has been touched. Enough liquid to get into all interproximal areas as a result of which efficient and predictable biofilm disclosure. No need to retract the cheeks or tongue, procedure is quick and localized , hence preventing and spill or mess.

Advantages of a disclosing agent17

For the clinician:

  1. Visualizing the dental biofilm
  2. The color guides the biofilm removal
  3. Once biofilm is removed predictably, calculus is easier to detect
  4. Faster, more efficient and minimally invasive
  5. Take Plaque indices

For the Patient:

Patients are shown areas where they need to brush better where biofilm has accumulated.

  1. Motivation, reeducation on oral hygiene
  2. Understanding the need for professional prophylaxis
  3. Personalized patient instruction and motivation
  4. Self-evaluation by the patient
  5. Effectiveness of oral hygiene maintenance

Case study for disclosing agent

  • This case study was the basis for using the disclosing agent as mandatory.
  • From this study done by Dr. Bastendorf and clinical team shows that when clinicians don’t use disclosing before treatment more that 20% of biofilm still remains which is invisible to the naked eye.
  • When disclosing agent was used, there was less than 6% of biofilm remaining.
  • Challenge clinicians on ethical practice here.
  • Use of a disclosing agent is mandatory for predictable and complete removal of supragingival biofilm.

Apprehensions of a disclosing agent

In the past patients clearly disliked disclosing agents as their entire mouth was coloured, using conventional methods of treatment, it was impossible to get the colour out from gingiva and soft tissues. Very time consuming, messy and most important- unpredictable in biofilm disclosure.

Important is the use of a disclosing agent in a prophylaxis treatment

Use of a disclosing agent as a guide for supra gingival biofilm removal is an effective method to be really efficient.18

Results suggest that pits and fissures should be cleaned with a plaque indicator and air polishers before placing a sealing material to ensure complete removal of plaque from the tooth.19

Bastendorf KD et al.20, Viorica C et al.21 all confirm higher efficiency in professional prophylaxis when done with the use of a disclosing agent Plaque disclosing agents, which are used to detect plaques on the tooth surface


1. Effect of visual method vs plaque disclosure in enhancing oral hygiene in adolescents and young adults: a single-blind randomized controlled trial, Peng Y  et al, American Journal of Orthodontics and Dentofacial Orthopedics 2014, 145(3)

2. DISCLOSING AGENTS IN PERIODONTICS: AN UPDATE, Zoya et al,2015; Journal Of Dental College Azamgarh 1(1):103-110

3. A survey of knowledge, attitude, and practice toward disclosing agents among dental students: A prospective study; M Namrata, Nandhini G Ashok, Dhanraj Ganapathy, International Journal of Orofacial Research, 2017;vol 2, issue 2, pages:48-50

4. A comparison of bacterial plaque disclosants in periodontal disease. Cohen et al 1972. J Periodontal 43(6):333-338

5. The prevention of pyorrhoea and dental caries by prophylaxis. Skinner, F. H. Dental Cosmos. 1914(56):229-309.

6. Experimental gingivitis in man. Loe, H., Thielade, E. & Jensen, S.B. Journal of Periodontology. 1965(36):177-187.

7. The effect of a preventive programme on dental plaque, gingivitis and caries in schoolchildren. Results after one and two years. Axelsson, P, & Lindhe, J Journal of Clinical Periodontology, 1974(1):126-138,

8. The disinfection of the oral mucosa with crystal violet and brilliant green.. Berwick, C. C.  Journal of Dental Research. 1920(2):21-42.

9. The dentist's management of young children, Easlick, K. A American Journai of Orthodontics. 1935(21):78-88.

10. Disclosing agents: their importance and uses. Raybin, M., The Dental Outlook. 1943(4): 159-162.

11. The use of disclosing agents for measuring tooth cleanliness. Amim, S, S. Journal of Periodontology. 1963(34):227-245.

12. Use of ultraviolet illumination in oral diagnosis. Heffemen, J. J., Cooley. R. O., Hale, J. B., Olsen, N.H. & Lyon, H.W. Journal of the American Dental Association. 1971(82): 1353-1360.

13. A fluorescent plaque disclosing agent. Lang, N. P., Ostergaard, E. & Loe, H.Journal of Periodontal Research. 1972(7):59-67.

14. A two-tone dye test  for dental plaque. Block, P, L, Lobene, R. R, & Derdivanis, J, P. Journal of Periodontology. 1972(43):423-426.

15. Dental Plaque- classification, formation and identification. Chetrus and Ion, 2013. International journal of medical dentistry 3(2) :139-143

16. Disclosing agents used in dentistry.D Datta, R. Kumar, A Narayanan, S Anandan, L Bapilus, June 2017, World Journal of Pharmaceutical Research, DOI: 10.20959/wjpr20176-8727

17. Plaque disclosing agent- A review. Shefali sharma et al 2010, J Adv Dental research 2(1):1-3

18. Efficacy of a disclosing plaque agebt as a guide to supragingival biofilm removal;Mensi etal, Poster presentation, Europerio9, 2019

19. Effectiveness of plaque indicators and air polishing for the sealing of pits and fissures R.H. Botti, M. Bossù, N. Zallocco, A. Vestri, A Polimeni, European Journal of Paediatric Dentistry ,  VOL. 11/1-2010

20. Kann die Qualität der Professionellen Zahnreinigung durch ein strenges, Bastendorf-Strafela N, Bastendorf K.- D, PlaqueNcare 2/2016

21. Dental plaque – classification, formation, and identification , Viorica chetru et al, International Journal of Medical Dentistry, volume 3,  issue 2 April/June  2013, pp. 139-143