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Earlier this month a study called the "Xylitol for Adult Caries Trial" was published in the Journal of the American Dental Association. Several of my dental friends contacted me, concerned to find out what was going on. If you look closely at the study, the results are not surprising, but the amazing thing was how quickly it reached the front page of the New York Times Health Section. I guess the conclusion of the study may seem shocking at first glance, because researchers found xylitol did not significantly reduce cavities in adults who are at high risk for decay.
The researchers confirmed xylitol has been shown to be successful in reducing cavities for over 50 years in Europe, Asia and even in the US. These studies, however, have mainly focused on children and adolescents, so this new study took a look at adults in the US with a high rate of cavities. The hypothesis was that 5 grams of xylitol could stop new cavities in selected clinic patients. After two and a half years, the conclusion was that xylitol had only reduced decay by 10%, which was not significant.
The results did not surprise me, nor a well-respected lecturer, Dr Graeme Milicich from New Zealand. His comment was, "Water can put out a fire, but a cup of water is not going to deal with a house fire. The people selected in this study were high-risk patients, so throwing a cup of water at the problem, without any other intervention, is obviously not going to deal with it". The patients in this study had serious decay problems and many had half their teeth missing. They experienced about 4 new cavities a year, yet it does not appear anyone addressed their lifestyle or other risk factors.
Xylitol's main benefit is its alkalizing ability. You can do a pH test in your own mouth and show that 100 percent xylitol quickly alkalizes your mouth to protect your teeth from acidity and sugars. This is why we recommend eating xylitol mints or gum after eating, after drinking and after snacking. If you eat xylitol and then sip diet soda or a 20 oz energy drink, the xylitol will have no chance to protect you. Most Americans snack frequently, particularly when it comes to sipping drinks.
To benefit from xylitol we must understand how teeth become damaged and how xylitol prevents the damage. If 5 pills a day could stop cavities – it assumes "cavities happen", which is not the case. Acidity is the pivotal risk factor for cavities. Acidity is from plaque and also from foods and especially drinks that lower mouth pH. Older adults with cavities usually have acidic saliva due to hormonal change, pregnancy, stress, medications, or a depressed immune system. In the age-range of this study, many patients would have acidic or insufficient saliva to counter acidic attacks from eating or drinking. Only with the correct xylitol protocol and correct home care regimen could these patients have avoided cavities.
Anyone can test with pH paper and see how xylitol (mints or gum) can alkalize the mouth within minutes of an acidic challenge, to stop acidic damage and help protect teeth. This study used xylitol without any education, which is similar to giving a couple of "diet pills" to obese patients without any dietary advice, and then being shocked that they didn't work!
Cavities are not a mystery or phenomenon – they are the progressive destruction of teeth to a point where the tooth caves in, allowing an infection to enter and destroy the tooth under the enamel. To prevent cavities, you must get rid of cavity-producing bacteria and protect teeth from acidity that weakens the outer enamel. The amount of daily prevention must outweigh the amount of damage to a tooth. I describe this as being like a bank balance, the outcome between how much you deposit each day vs. how much you withdraw. If the amount of damage to teeth exceeds the amount of help you give each day – you will end up with cavities. If you offer more protection than damage, cavities will stop. For adults with decay, it is important to control acidic damage from snacking habits. Xylitol offers us all a simple and delicious tool, but it is the person who must make the effort, use xylitol to limit damage, and understand that even xylitol is not a magic pill!