Summary of: The assessment of oral dryness by photographic appearance of the tongue

Key Points

  • Suggests that clinical investigation of the oral cavity and collection of saliva is indicated for diagnosis of oral dryness.

  • Stresses it does not seem possible to diagnose oral dryness by mere visual inspection of photographed tongues.

  • Informs dentists are as good as non-dentists in judging intraoral pictures of the tongue. Therefore more insight in aspects of judging oral dryness by visual inspection is needed.


Background Oral dryness or hyposalivation is a major clinical problem. Several chairside tests or visual inspections of the oral cavity have been proposed for the assessment.

Objective To identify whether photographs of the tongue could be used to identify oral dryness.

Material and methods Twenty-five dentists and 25 individuals with another academic background were recruited. They assessed the severity of the oral dryness of 50 patients, based on an intraoral picture of each patient. The oral dryness was quantified with a five-point Likert scale and the scores were subsequently compared with the salivary flow rate and the level of xerostomia of these patients.

Results No relation was found between the unstimulated salivary flow rate of a patient and the average oral dryness score, determined by dentists (p = 0.260) as well as non-dentists (p = 0.806). Also no relation was found between the self-reported xerostomia level of the patient and the average dryness score assessed by the dentists (p = 0.171) or non-dentists (p = 0.477).

Conclusion It does not seem possible to diagnose oral dryness by mere visual inspection of photographed tongues. Thus, for correct diagnosis of oral dryness further clinical investigation of the oral cavity and collection of saliva is indicated.


C. P. Bots, A. V. Beest, H. S. Brand British Dental Journal 2014; 217: E3

Editor's summary

If two negatives make a positive, as we are assured by mathematicians that they do, then this research paper is a good contribution to the literature. Its two negatives are that clinicians are not good at assessing dry mouth by visual means alone and that attempting to do so by photography, or teledentistry, is not an effective technique either.

Journals are often criticised for not publishing research with negative results, and so for this reason too perhaps we may be viewed positively as we felt that this paper has important messages and lessons that could be learnt for daily dental practice.

With more people retaining more natural teeth for longer and with the increase in poly-pharmacy in the older population in particular, the occurrence of dry mouth is also rising. Consequently, all developments that aid the diagnosis, analysis and treatment of this often distressing and discomforting condition are very welcome. This research aimed to discover if diagnosis of xerostomia might be possible by the intermediary of photographs but it seems that this is not to be recommended.

The use of photographs was a deliberate strategy in the research method in removing the opportunity for the patient and clinician to communicate. However, this does serve to highlight how important it is to have a dialogue as to whether the patient thinks that they have a dry mouth or symptoms of this. A face-to-face consultation makes this entirely possible and obviously desirable especially as the condition of dry mouth has a variety of impacts on lifestyle such as eating, diet, social implications and so forth requiring advice to make changes in habits and self-care. Divorcing the mouth from the patient (by not communicating effectively) will not only hamper diagnosis but will also potentially obstruct effective means of solving the problem and the oral health consequences.

We should not, of course, dismiss the possibility of using photographs and images across the board for similar diagnostic purposes. There may well be instances in which this technique could be helpful, more accurate and save valuable time and other resources. What is clear is that it needs to be assessed on a case by case basis.

The full paper can be accessed from the BDJ website ( ), under 'Research' in the table of contents for Volume 217 issue 2.

Stephen Hancocks


Author questions and answers

1. Why did you undertake this research?

For over 15 years, a saliva clinic has been held at the Academic Centre of Dentistry in Amsterdam. The clinic is visited by a large number of patients with dry mouth complaints, who are studied extensively to find a possible cause for their problems. The severity of the dry mouth is assessed with several objective and subjective parameters. Over those years we have been confronted with dentists who doubt the added value of these investigations, claiming that they just have to look in the oral cavity in order to determine whether the mouth is dry or not. Therefore, we decided to perform a study in which we explored whether dentists are indeed able to visually determine oral dryness in patients.

2. What would you like to do next in this area to follow on from this work?

A limitation of the present study is that the dentists had to judge the level of oral dryness based on photographs of the tongue of patients. It might be that clinical aspects like colour and glance aren't optimally depicted on photographs. It is also possible that dentists need a view at the mucosa for a correct conclusion about oral dryness. We would like to perform a follow up study, in which dentists should look at the oral cavity of real patients to determine oral dryness, instead of looking only at intraoral photographs. In such a study, we could also explore the added value of a structured visual oral inspection of the oral cavity, using the clinical oral dryness score (CODS score).


As undergraduates, most dentists have been taught that dry mouth is invariably the result of low salivary flow; that every patient who complains about having a dry mouth has a flow rate that is considerably lower than normal. Similarly, every patient with a demonstrably low salivary flow would be sure to be complaining about having a dry mouth. This notion was partly due to the absence of information to contradict such a simplistic assumption and partly due to a mechanistic view of oral conditions that relied almost entirely upon visual diagnosis rather than their impact on people's day-to-day lives. The experiential approach — whereby patients are asked about their symptoms — was generally viewed as lacking validity and reliability: patients simply couldn't be trusted to be reliable observers of their own health states. The objective measurement of salivary flow was seen as a better way to determine whether someone has dry mouth than actually asking that individual whether he/she suffers from dry mouth. Although this has been steadily changing, with growing awareness of the usefulness of self-report information (and a formal framework through which to use it) leading to the development of a number of self-report scales for use in dentistry, acceptance of other approaches to dry mouth measurement and diagnosis has been patchy at best.

The findings of this study by Bots et al. show that, at least when photographs are used, it is not possible to identify someone with a low salivary flow rate, and (somewhat surprisingly) that clinicians are no better than well-educated lay people where this is concerned. The dentists involved in the study felt that more clinical information would be required to make a valid diagnosis, and that a photograph of the tongue does not provide enough diagnostic clues or cues. Attempts have been made to systematise the use of clinical information in diagnosing dry mouth. For example, the Challacombe scale1 is a measure that was designed for clinical use as an objective score for oral dryness, based entirely upon clinical observations by a dentist; it is a checklist that has arisen from experienced clinicians' observations over many years. It has no subjective aspect; the individual being assessed is not asked about his/her symptoms. Some clinical validity has been demonstrated, but its utility remains unclear as yet, so those planning to use it should also collect other information on dry mouth.

The findings of Dr Bots and colleagues offer support for a multi-pronged approach to measuring dry mouth and identifying those who are suffering. Clinicians should not rely solely on clinical observation or salivary flow measurement; asking the patient is a good idea, and validated measures are available for this purpose.2 Finally, telemedicine is rather trendy at present, but this study's findings suggest that teledentistry might perhaps be a little further off.


  1. 1

    Osailan S M, Pramanik R, Shirlaw P, Proctor G B, Challacombe S J . Clinical assessment of oral dryness: development of a scoring system related to salivary flow and mucosal wetness. Oral Surg Oral Med Oral Pathol Oral Radiol 2012; 114: 597–603.

    Article  Google Scholar 

  2. 2

    Thomson WM, van der Putten G J, de Baat C et al. Shortening the xerostomia inventory. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2011; 112: 322–327.

    Article  Google Scholar 

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Thomson, W. Summary of: The assessment of oral dryness by photographic appearance of the tongue. Br Dent J 217, 80–81 (2014).

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