HKU Bulletin May 2004 (Vol. 5 No. 3)

12 13 RESEARCH Restoring Oral Health ‘D ry mouth’ is a problem most of us wash away with a glass of water. But for some patients, it can mean lifelong problems with eating and speaking. These are quality-of-life issues, according to Professor Anne McMillan of the Faculty of Dentistry, who has been investigating how to improve a dry mouth and give patients a better life. A dry mouth occurs when the salivary glands stop working. Saliva is necessary to chew, swallow, speak and hold dentures in place, and lack of it also leads to tooth decay. “Most of us don’t realize how important saliva is until it’s not there. If the mouth is very dry, your tongue sticks to different parts of the mouth. Eating is difficult because you need saliva to start the digestion process,” said Professor McMillan, who specializes in oral rehabilitation. Patients lose the ability to produce saliva either as a side effect of treatment for other conditions, or as a problem on its own. Nasopharyngeal carcinoma patients have been especially susceptible. The cancer is located deep under the brain and traditionally has been bombarded with large blocks of radiation. This destroys the cancer cells, but also the sal ivary glands, leaving patients with a dry mouth for the rest of their lives. Not much can be done to help them, other than trying to keep the mouth moist with water, which is not very effective without saliva. So Professor McMillan and her team have been working with cl inical oncologists at Queen Mary Hospi tal to prevent the damage in the first place. The oncologists have devised a treatment that delivers pencils of radiation from different angles, thereby causing less damage to other tissues. The treatment started in 2000 and Professor McMillan has been tracking patients’ progress. The preliminary findings show a marked improvement in saliva levels and quality- of-life over traditional radiotherapy, especially six to 12 months after treatment, she said. “We’re discovering that the recovery of saliva is good enough to sustain pretty good oral health. In terms of quality-of-life, they aren’t having the problems with speaking and swallowing and chewing,” she said. “What matters in the end is how the patients feel. Q ” uality-of-life is also a consideration for patients who suffer a dry mouth as a result of a medical condition, Sjögren’s syndrome. This affects mainly middle-aged or older women and involves the drying up of the salivary and lachrimal glands – responsible for keeping the mouth and eyes moist . I t is associated wi th rheumatoid arthritis and lupus. Professor McMillan and her team are working with the division of rheumatology at Queen Mary Hospital on a controlled clinical trial of a new drug to treat the oral effects of the syndrome. (Drug treatment for a dry mouth requires some saliva to be present to be effective, which is not the case after traditional radiotherapy for nasopharyngeal cancer.) The drug, Cevimeline, can improve a dry mouth and has much less serious side effects than previous drugs. The trial is looking at the effectiveness of Cevimeline for Sjögren’s syndrome patients and its impact on quality-of-life. Another collaborative effort is examining quality-of-life issues for stroke patients. Although they do not suffer dry mouth, they still have difficulty speaking, chewing and maintaining oral health. Professor McMillan is working with the rehabilitation unit at Tung Wah Hospital to devise methods to improve these problems, such as adjusting the shape of toothbrush handles so they are easier to hold. The impact on the quality-of-life of patients and their families are being studied both in the hospital and at home. “One of the issues medics and dentists are always grappling with is perceptions of health. Our perceptions are often not the same as the patients’,” Professor McMillan said, in explaining the need to look at patents’ quality-of-life. She cited an earlier outreach project by the Faculty in which the elderly were offered free dental care for simple procedures, but not denture fitting or repair. The Faculty staff thought the project went well, but the patients were not satisfied because their main concern was with dentures. “Obviously if you don’t satisfy the needs of the patient, you aren’t going to have a successful outcome,” she added. Pathologist and Engineer Use their Heads R econstructing the faces of crime victims from a skull is one of the great ar t forms of cr iminal invest igat ion but forensic pathologist Philip Beh decided it was time to turn this into a science by using his head: literally. The Associate Professor of the Department of Pathology subjected his own head to a CT Scan to test out his theory on how to create a standard model for recreating the true identity of someone from measurement of their skull. Unti l now detectives have had to rely on the instinct of sculptors who build on a standard but limited set of indicators drawn up from 20 to 30 soft tissue points on the face used to gauge the skin and muscle thickness. Beh said: “This gives a rough guide as to how big the muscles are but it’s limited to those points and you have to rely on the artistic skill of the sculptor. “But i f you can use CT scan data you can use a few thousand points and then using a computer you can make it cheaper, faster and more reliable.” With the help of Dr Ian Gibson, Associate Professor f rom the Depar tment of Mechanical Engineering, Beh has been trying to develop a model for Chinese racial faces and will be using 40 male and 40 female patients. But before going down this avenue Beh has to get the green l ight from a hospi tal , as wel l as assess the resul ts from his own experiment with a CT scan. Once Beh had undergone the scan, Gibson was able to create a model of his skull and a model of his face to show that the system works. Now they want to develop the informal project with funding. The initial idea began to germinate in Beh’s mind in 2000 when he met some American researchers from General Electric (GE) at a conference held at an FBI facility. It was not, however, until early last year that Beh and Gibson began to do their preparatory work. When Beh then met up with the Americans in Turkey, in 2003 they decided to link their complementary projects together. Eventually Beh hopes to feed his data into GE’s software and computer system to provide a comprehensive model for different racial groups. He said: “We want to be able to test the prototype and be one of the first centres in the world to use this kind of technology. My aim is to turn an art into a science and help law enforcement agencies in the process.” Philip Beh and his heads.