A new study suggests that dental X-raysmay increase the risk ofthe most common kind of brain tumor.However, experts say the risk of thesemostly non-cancerous growths is still very small.The study involved about fourteen hundred patientswith brain tumors called meningiomas.They were compared with a control groupwithout brain tumors.Elizabeth Claus of Yale University in Connecticutled the study.She says there was a clear relationshipbetween dental X-rays and the brain tumors.ELIZABETH CLAUS: "We found that the individualsthat were diagnosed with meningiomawere essentially about twice as likelyto report having a specific type of X-ray,which is very common, a bitewing."The link was greater with a different kind of imaging,called a panoramic X-ray.There was up to five times the risk,depending on age or how often the X-rays were taken.Dr. Claus points out that in this study,the people were generally in their fifties or older.They were asked to remember X-raysthey might have had many years earlier.ELIZABETH CLAUS: "There is always some difficultyin people remembering past exposures.And so patients could under-or over-report their dental X-rays.And so you always have to keep that in mind."Dr. Claus says she does not wantto scare people away from dental visits.ELIZABETH CLAUS: "The big take-home message is,keep going to the dentist.But have a conversation with your dentistabout whether you might be ableto reduce the number of X-rays that you receive."Her research paper appearsin the American Cancer Society's journal, Cancer.During dental procedures,and even when people brush their teeth,mouth bacteria often enter the blood system.A popular belief is that gum diseasecan lead to heart attacks.But last week, Circulation,a journal of the American Heart Association,published a statement saying there is no scientific proof.The statement says gum disease has not been provento cause heart disease or stroke.And, it says, treating gum diseasehas not been proven to prevent them.There is also not enough evidence to know whether brushingand flossing regularly can prevent heart disease.A committee of heart doctors, dentistsand infectious disease specialistsconsidered five hundred journal articles and studies.They say there is not enough evidenceat this time to confirm a cause-and-effect relationshipbetween gum disease and heart disease.Both diseases are often found in the same patient.But the experts say this is possiblybecause of risk factors common to both diseases.People who do not pay attention to risk factorslike smoking, diabetes or high blood pressuremay not pay close attention to their oral health either.And that's the VOA Special English Health Report.