Dental Tribune Indian Edition

10 Dental Tribune Indian Edition - July 2013Clinical General Dentistry MORADABAD/ELURU, India: New research from India suggests that dairy products may positively affect oral health. In a study of almost 70 teenagers, the researchers obser- ved that cheese in particular raised the plaque pH in the participants’ mouths. As high pH levels are asso- ciated with a lower risk of develo- ping cavities, they believe that dairy products may help protect against cavities. The study involved 68 partici- pants aged 12–15 who were assigned randomly to three groups. The first group was instructed to consume 10 g of cheddar cheese, the second group drank 15 ml of milk contai- ning 3.5 percent fat, and the third group was given 10 g of sugar-free yogurt. After a baseline oral health analysis, all participants chewed or swished their respective product around their mouth for 3 minutes and then rinsed with water. Afterwards, the plaque pH level was assessed at different time intervals. According to the study, the mean plaque pH in the cheese group rose rapidly after 10 minutes and decrea- sed slightly after 20 and 30 minutes, but the plaque pH at 30 minutes was still slightly higher than at baseline. No such development was observed in the other groups. After 30 minutes, the plaque pH in the milk group was simi- lar to that of the baseline pH, while it was slightly lower in the yogurt group. However, none of the dairy products lowered the plaque pH below the criti- cal pH of 5.5, which is associated with enamel demineralisation and dissolu- tion, the researchers said. They attributed the anticarioge- nic activity of these products to the direct chemical effects of casein, phosphopeptides, calcium, and pho- sphate. Another explanation is that the action of chewing increased saliva production, which led to a rising pH level. Although additional studies are needed, the findings of this study sug- gest that dairy products have low ca- riogenic potential, with cheese having the highest anticariogenic property, the researchers concluded. The study was conducted at the Kothiwal Dental College and Rese- arch Centre in Uttar Pradesh, India, in collaboration with the St Joseph Den- tal College in Andhra Pradesh, India. It was published in the May/June issue of the General Dentistry journal. DT The surveillance of patients is a dentist’s duty An interview with Prof. Newell Johnson, Australia Oral cancer poses a continuing challenge for dental practitioners worldwide. At the FDI Annual World Dental Congress in Hong Kong, Dental Tribune’s Group Editor Da- niel Zimmermann had the oppor- tunity to speak with Prof. Newell Johnson from Griffith University’s School of Dentistry and Oral Health in Southport, Australia, about the di- sease and new methods of identifica- tion and treatment. Daniel Zimmermann: Oral can- cer figures seem to be increasing worldwide, despite awareness cam- paigns run by dental organisations like the FDI. Are we in danger of losing the battle against the disease? Prof. Newell Johnson: There is some good news. In countries that have long had the reputation of having very high rates of oral cancer, such as parts of France, India, and Sri Lanka, the ra- tes of alcohol and tobacco-related oral cancer are indeed falling. The same is true of the U.S., much of Western Europe, and Australia. Here rates are falling from a lower base. In those countries or populations with traditionally very high rates, ho- wever, hundreds of thousands still die of oral cancer every year. In parts of Eastern Europe and the former Soviet republics, rates of these cancers are rising, we think, because of still high tobacco use, abuse of alcohol and a poor diet. The other piece of bad news is that the incidence of cancers of the oro- pharynx (as opposed to the lip and in the mouth itself) is also increasing worldwide. HPV has been identified as a growing risk factor for oral cancer. What part does the sexual transmission of the virus play in the development of the disease compared with more commonly known factors like smo- king or drinking? Certain types of the human papillo- mavirus are indeed strongly associa- ted with cancers of the upper aero- digestive tract, particularly of the tonsils and base of the tongue, rather than in the mouth itself. These are the same viruses that we know cause cancers of the uterine cervix, penis, and anus. It is generally thought that sexual transmission is involved. The evidence is largely circumstantial; that is, these cancers are more likely among younger adults, and there are associations with the number of sexual partners. Fortunately—if that is an appro- priate word—these cancers are more sensitive to radiotherapy, and the sur- vival rates/treatment outcomes are better than for most other head and neck cancers. For the past decade, there have been extensive immunisation pro- grammes against these particular papillomaviruses delivered to girls in many countries. These are inten- ded to prevent cancer of the uterine cervix in later life. It will be very interesting to observe, in another 20 years or so, whether this has had an impact on upper aerodigestive tract cancers too. Fortunately, we are be- ginning to see boys now included in the immunisation programmes in some countries. Some forms of oral cancer have a patient survival rate of only 50 per- cent. What makes it so difficult to achieve a more successful therapeu- tic outcome? The average survival at five years af- ter diagnosis of oral cancer has hove- red around 40–50 percent for decades in most countries. In the high-volume specialised treatment centres, patients are indeed doing better, in terms of long-term survival and quality of life/ minimisation of disability and side- effects. The major reasons that we are not doing even better is because so many cases are diagnosed and trea- ted so late, and/or patients have severe comorbidities, such as diseases of the cardiovascular system or cancers at other sites. Dentists can play a vital role in the identification of early signs of oral cancer. Is the profession sufficiently prepared for this role? Well, of course one cannot generalise. Many dentists and other members of the oral health team carry out excel- lent surveillance of each patient. This is indeed our duty. It might be cal- led “opportunistic screening”. Many national dental associations, and the FDI, vigorously promote such beha- viour. There are many excellent trai- ning programmes for the detection of patients and lesions at risk. This should go hand in hand with support from dentists for tobacco prevention/ cessation, moderation of alcohol con- sumption, promotion of healthy diets and good hygiene (oral and sexual) for all their clients. On the other hand, the prevalence of potentially malignant disorders, and certainly of overt oral cancer, is low in many countries, so maintai- ning a high level of awareness and interest among general practitioners is difficult. Some are discouraged be- cause cancer screening may not be a remunerable activity. In South Asia, and emigrant com- munities therefrom, potentially mali- gnant oral disorders are common, and we have much activity with the professions and the public in these parts of the world. Recently, a study published in the Cancer Research journal has proposed a method of treatment by blocking a protein that plays an important part in the spread and return of oral cancer. What are your views on this rese- arch and what are other promising therapeutic approaches? There are very many biochemical/ molecular pathways involved in cell division, maturation, migration and metastasis, and death within tissues. Many are targets of investigation and manipulation. Some will prove irrelevant—or at best epiphenome- na. Interference with some will also affect normal tissues, especially if they represent exaggeration of pathways that are part of normal cellular controls. An attraction of this particular work is that it seeks to understand pathways critical to stem cells—those cells that provide the basis for con- tinued cell renewal. At the moment, the observations on this pathway in human cancers have been explored in experimental animals. It is some way from human treatment trials, though there are many human studies of other putative biological treatments for oral, and other cancers. In principle, this is the way forward. There are a number of oral cancer- screening systems available on the market but their penetration is still very low. Why is this technology not yet part of dental practice? For cancers, and for potentially ma- lignant disorders, in the mouth itself, direct visual inspection and palpation, followed by referral or biopsy, is the best approach. Adjunctive screening tests have not been demonstrated to have utility beyond this and commer- cialisation can be counterproductive. You have already mentioned gene- tics. What role will it play in the eva- luation of oral cancer in the future? Well cancer is, of course, a genetic dise- ase. There is a small component of inhe- rited genetic susceptibility, but nothing as important as with breast cancer, for example. There is a large component of acquired genetic abnormality, which is being gradually unravelled. So gene- tic testing is of increasing importance, perhaps for susceptibility, more so for early changes in the tissue during carci- nogenesis, the latter perhaps detectable in saliva or blood too. However, every cancer is a unique biological event in an unique indivi- dual. Detecting the spectrum of ge- netic abnormalities in the individual patient, and targeting these with parti- cular designer drugs, or gene therapy or immunotherapy is exciting: we are in the era of personalised medicine. Extensive surgery, radiotherapy, and chemotherapy have not brought the improved outcomes we so despe- rately need. For the afflicted, the futu- re will be individualised biotherapies. For the world, the future must be pri- mary prevention. Thank you very much for this inter- view.DT Prof. Newell Johnson Consumption of certain dairy products may prevent cavities A new study has suggested that milk and milk-based products may help reduce the inci- dence of dental caries. (Foto: Jenny Sturm/Shutterstock)