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Dental Tribune Middle East & Africa Edition | September-October 20142C HYGIENE TRIBUNE Figure 1. Digital Plaque Imaging Picture i: Pre-treatment - pre-brush plaque area: 24% Picture ii: Pre-treatment - post- brush plaque area: 13% Picture iii: Post treatment - pre- brush plaque area: 4% Picture iv: Post treatment - post- brush plaque area: 3% Developing oral care products imaging and innovation ByPaul Sagel P PD hears from research fellow in oral care at Procter & Gamble Paul Sagel, as he explains how ad- vances in digital imaging are being used to improve oral health. The development of innovative oral care products requires the willingness to think outside the box and exercise diligence. The ultimate goals are to produce products that meet a need, suc- ceed in the marketplace and help make a difference in pa- tients’ lives - such as the confi- dence that a whiter smile gives someone, or the patient who re- verses gingivitis with the help of anti-bacterial dentifrices and superior toothbrushes. Digital imaging is a prime example of such thinking and has become an integral part of product de- velopment at Procter & Gamble. Space Age Technology Digital imaging in oral care began with efforts focused on quantifying dental plaque and later on tooth colour measure- ment and eventually on to gin- gival health assessments. As with many instrumental tech- niques used today in dentistry, the fundamental technology is usually developed outside the world of oral care. For example, accurate and precise colour measurement and the govern- ing mathematics were devel- oped for colour matching in the paint industry. Thinking inno- vatively, it was clear that there was great potential in the oral care research field if this could beadapted.Wewerelookingfor technologies that would give us rapid and objective results to improve product development and the time it took to bring new products to dental profes- sionals and the general public. The internal research at Proct- er & Gamble on digital imag- ing was originally conceived as a method to assess the anti- plaque activity of dentifrices and was then later also used as a method to assess tooth whit- ening. Typically, testing for anti-bacterial activity has in- volved clinical studies and the use of standard plaque and gingivitis indices such as the Turesky index or Löe and Sil- ness Index. These are subjec- tive assessments that involve clinical measurements and judgement, and that often re- quire large sample sizes to as- sess the potential efficacy of prototype technologies and product designs. Digital imag- ing is reliable, fast and objec- tive; it allows the research team to efficiently and objectively screen potential products in vivo. Digital imaging also pro- duces a source image which can be analysed in a variety of ways after the study is com- plete. Digital Plaque Imaging The assessment of anti-plaque activity using digital imaging involves automated measure- ment of the area of plaque on the facial aspects of the anterior teeth. After disclosing the teeth with fluorescein, the dentition is digitally imaged in the pres- ence of standardised long wave UV lighting. Using a computer algorithm, the pixels are then individually assigned to plaque, teeth, gingivae or background based on colour. The areas of coloured pixels associated with the disclosed plaque are then summed up to determine the amount of plaque present. Similarly, the area of pixels for the teeth and plaque combined is summed up, and then a cal- culation is made to determine the plaque coverage as a per- centage of the total area. In this manner, it is possible to make a precise and objective determi- nation of the significant reduc- tions in plaque obtained with the stabilised stannous fluoride contained in Oral-B Pro-Ex- pert. One study using digital plaque imaging, conducted in 2009, gives an example of its use to determine the effectiveness of anti-plaque agents. Using this technology, it was possible to objectively measure statisti- cally significant overnight and daytime plaque reductions with use of stabilised stannous fluoride/sodium hexameta- phosphate dentifrice relative to a marketed control. Other research using digital plaque imaging showed a 24.4% re- duction in overnight plaque growth using stannous fluo- ride dentifrice. Digital plaque imaging is an ideal method to assess plaque reductions - it’s a real step forward to objectively prove the efficacy of products, more quickly optimise them and then introduce them to im- prove the lives of consumers. Regimens have also been test- ed using digital plaque imag- ing. As an example, one study assessed overnight plaque coverage and plaque coverage following brushing with a stan- dard fluoride dentifrice. We then compared the esults with overnight plaque coverage and post-brushing plaque coverage following two weeks of use of a regimen which included twice- daily brushing with stannous fluoride dentifrice and twice- daily rinsing with cetylpyri- dinium chloride (CPC) mouth- rinse. As shown in Figure 2, the differences were dramatic - they were measured using digital plaque imaging which provided objective evidence for the efficacy of the regimen. Digital Whitening Imaging Digital imaging at Procter & Gamble was next used to de- termine the effectiveness of tooth whitening formulations and products. As with digital plaque imaging, this enabled the research team to rapidly and objectively assess the ac- tual benefits of products. It first provided proof of concept and later clinical proof for the ef- fectiveness of hydrogen perox- ide formulations contained in a novel and disruptive whitening product that delivered the whitening agent on a thin plas- tic strip which was applied directly to the teeth (Crest Whitestrips). Imaging also provided the objective com- parative whitening results that were needed to prove that this product worked better than many tray-based whitening products. The digital imaging provided a robust method for the evaluation of whitening ef- ficacy, with research showing that the clinical measurement of tooth colour via digital im- aging is accurate, precise and reliable. Fast Forward to The Present The research and development team at Procter & Gamble now has extensive experience using digital imaging to assess anti- bacterial activity and whiten- ing efficacy. This technology is currently used to develop just about every oral care product at Procter & Gamble. It is ex- cellent for research and also makes a great demonstration tool to visually show the effi- cacy of our products. Procter & Gamble has also used digi- tal imaging at conventions and been able to show dentists and dental hygienists images of their own dentition. Even a very small amount of plaque is so easily visible using this technology that you can re- ally see the difference. Digital imaging technology is creden- tialed by ASTM International (previously the American So- ciety for Testing and Materials (ASTM)). Rather than just visual dra- matisations, seen in some advertising, by using this cre- dentialed, objective imaging technology it is possible to show actual plaque reductions and/ or colour improvement. It also allows rapid assessment of competitive products for results that make strong, truthful per- formance claims possible. In the early 1990s, Procter & Gamble spent countless hours developing this technology and realised that it is prudent for the entire industry to have ac- cess to the technology so that all products and technologies can be objectively evaluated. The company invites everyone to evaluate their products with this objective imaging system and often places imaging sys- tems at other companies and universities so that they can use the technology as well. The plaque imaging system was also on display at the American Dental Association a few years back. The Future With respect to the future of digital imaging, the difference between conventional imaging and microscopy is closing due to the advent of highresolution cameras. From the early begin- nings using digital imaging, the research team at Procter & Gamble has continued to de- velop and explore other uses for it. We currently use imaging to measure plaque, gingivitis and colour. Looking further into the future, it is possible to foresee digital imaging being used to measure biochemical markers associ- ated with oral disease. For a list of references or to ask a question/comment on this ar- ticle, email PPD@fmc.co.uk digital plaque imaging 1. Disclose the teeth with fluorescein 2. Take digital images of the facial surfaces with standardised UV lighting 3. Automated (computerised) assignment of pixels (to plaque/tooth/ gingivae/ back- ground) 4. Summation of the area of pixels associated with plaque 5. Summation of the area of pixels associated with teeth and plaque combined 6. Calculation of the percentage of the summed total area of pixels associated with plaque