Thursday, July 28, 2011

Study shows bone fluoride levels not associated with osteosarcoma


The International and American Associations for Dental Research have released in its Journal of Dental Research a study that investigated bone fluoride levels in individuals with osteosarcoma, which is a rare, primary malignant bone tumor that is more prevalent in males. Since there has been controversy as to whether there is an association between fluoride and risk for osteosarcoma, the purpose of this study, titled "An Assessment of Bone Fluoride and Osteosarcoma," was to determine if bone fluoride levels were higher in individuals with osteosarcoma.

No significant association between bone fluoride levels and osteosarcoma risk was detected in this case-control study, based on controls with other tumor diagnoses.

In the case-control study, by lead researcher Chester Douglass of Harvard University, patients were identified by physicians in the orthopedic departments from nine hospitals across the U.S. between 1993 and 2000. In this report, the study sample included incident cases of primary osteosarcoma and a control group of patients with newly-diagnosed malignant bone tumors. Specimens of tumor-adjacent bone and iliac crest bone were analyzed for fluoride content. The study was approved by the Institutional Review Boards of the respective hospitals, Harvard Medical School and the Medical College of Georgia.

Logistic regression of the incident cases of osteosarcoma (N=137) and tumor controls (N=51), adjusting for age and sex and potential confounders of osteosarcoma, was used to estimate odds ratios (OR) and 95% confidence intervals (CI). There was no significant difference in bone fluoride levels between cases and controls. The OR adjusted for age, gender, a history of broken bones was 1.33 (95% CI: 0.56-3.15).

"The controversy over whether there is an association between fluoride and risk for osteosarcoma has existed since an inconclusive animal study 20 years ago," said IADR Vice-president Helen Whelton. "Numerous human descriptive and case-control studies have attempted to address the controversy, but this study of using actual bone fluoride concentrations as a direct indicator of fluoride exposure represents our best science to date and shows no association between fluoride in bone and osteosarcoma risk."

Monday, July 18, 2011

Use of Twitter for public health surveillance of dental pain


The microblogging service Twitter is a new means for the public to communicate health concerns and could afford health care professionals new ways to communicate with patients. With the growing ubiquity of user-generated online content via social networking Web sites such as Twitter, it is clear we are experiencing a revolution in communication and information sharing. In a study titled "Public Health Surveillance of Dental Pain via Twitter," published in the Journal of Dental Research—the official publication of the International and American Associations for Dental Research (IADR/AADR), researchers demonstrated that Twitter users are already extensively sharing their experiences of toothache and seeking advice from other users. Researchers Natalie Heaivilin, Barbara Gerbert, Jens Page and Jennifer Gibbs all from the University of California San Francisco (UCSF), Preventive and Restorative Dental Sciences, authored this study.

The researchers investigated the content of Twitter posts meeting search criteria relating to dental pain. A set of 1,000 tweets was randomly selected from 4,859 tweets over seven nonconsecutive days. The content was coded using pre-established, non-mutually exclusive categories, including the experience of dental pain, actions taken or contemplated in response to a toothache, impact on daily life and advice sought from the Twitter community.

After excluding ambiguous tweets, spam and repeat users, 772 tweets were analyzed and frequencies calculated. Of those tweets, 83% were primarily categorized as a general statement of dental pain, 22% as an action taken or contemplated, and 15% as describing an impact on daily activities. Among the actions taken or contemplated, 44% reported seeing a dentist, 43% took an analgesic or antibiotic medication and 14% actively sought advice from the Twitter community.

This research was funded by grants from the National Institutes of Health, the National Center for Research Resources, the National Institute of Dental and Craniofacial Research, the Office of the Director, and the UCSF Clinical & Translational Science Institute.

"This paper highlights the potential of using social media to collect public health data for research purposes," said JDR Editor-in-Chief William Giannobile. "Utilizing Twitter is an interesting, early stage approach with potential impact in the assessment of large sets of population information."

A perspective article titled "Using Social Media for Research and Public Health Surveillance" was written by Paul Eke of the Centers for Disease Control. In it, he states that the extensive reach of Twitter is currently being used successfully in public health to distribute health information to the segments of the public who access Twitter, but there are major limitations and challenges to be overcome before Twitter and its data products can be used for routine public health surveillance.

Visit for links to the complete articles or contact Ingrid L. Thomas at to request the PDFs.

About the Journal of Dental Research

The IADR/AADR Journal of Dental Research is a multidisciplinary journal dedicated to the dissemination of new knowledge in all sciences relevant to dentistry and the oral cavity and associated structures in health and disease. At .02261, the JDR holds the highest Eigenfactor Score of all dental journals publishing original research and continues to be ranked number one in Article Influence Score, reflecting the influential nature of the Journal's content.

About the International Association for Dental Research

The International Association for Dental Research (IADR) is a nonprofit organization with nearly 11,000 individual members worldwide, dedicated to: (1) advancing research and increasing knowledge to improve oral health, (2) supporting the oral health research community, and (3) facilitating the communication and application of research findings for the improvement of oral health worldwide. To learn more, visit The American Association for Dental Research (AADR) is the largest Division of IADR, with nearly 4,000 members in the United States. To learn more, visit

American Academy of Pediatric Dentistry Responds to Institute of Medicine Report


Report: "Improving Access to Oral Heath Care for Vulnerable and Underserved Populations"

The American Academy of Pediatric Dentistry (AAPD), the recognized leader in children’s oral health, welcomes the attention and the awareness of the Institute of Medicine (IOM) to improving access to oral health care, especially for the most vulnerable children. The mission of the AAPD is to promote optimal oral health for all children, and our members are the frontline providers of oral health care for the nation’s infants, children, adolescents and patients with special health care needs. By the nature of their training, pediatric dentists are able to provide comprehensive oral health care to children. Pediatric dentists treat a higher percentage of Medicaid and Children’s Health Insurance Program (CHIP) patients than any other type of dentist, and are especially successful with this population because of their advanced clinical training and expertise in behavior guidance. While all pediatric and many general dentists treat children, pediatric dentists train 100 percent of all the dentists who treat children.

The AAPD agrees with many recommendations cited within the IOM report, including the suggestion for raising dental reimbursement rates for Medicaid and CHIP. According to research published in the July 12, 2011 edition of the Journal of the American Medical Association (JAMA), “Higher Medicaid payment levels to dentists were associated with higher rates of receipt of dental care among children and adolescents.”(1) An estimated 70% percent of AAPD members participate in Medicaid and CHIP, but this percentage would be even higher, and would dramatically increase among general dentists, if these programs were funded closer to market-based rates. Indeed, this is far more important to access than the ethnic or gender composition of the dental workforce, since dental office overhead costs are similar for all dentists.

According to AAPD President Dr. Rhea M. Haugseth, “The AAPD is concerned that the IOM report did not emphasize enough the importance of and proven effectiveness in disease prevention by establishing a Dental Home by age one—usually in a private dental practice setting. Such early intervention keeps children from developing oral disease—commonly called cavities—and starts them out on a lifetime of good oral health. It is imperative to have the child and their parent or caregiver in the office at an early age in order to encourage good oral hygiene and diet, and emphasize preventive dentistry. We believe that the IOM report missed a golden opportunity to stress the importance of seeing a dentist by age one. Unfortunately, this could be the result of the IOM having no private practicing pediatric dentists serve on the committee that wrote the report.”

“The IOM report is also much too muted on the importance of oral health literacy. Many organizations, including the AAPD, are working on this front, but these messaging efforts require widespread education in schools and other areas outside of the dental or medical office. Many preventive practices to reduce oral disease can be incorporated at home, such as regular brushing, flossing, and a healthy diet,” concluded Haugseth.

The IOM report suggests spending even more federal funds on oral health services in Federally Qualified Health Centers (FQHCs). In 2000, Congress provided greater state flexibility for creating new and exclusive reimbursement mechanisms for FQHCs under Medicaid. Additionally, in 2002, Congress created a new “facility” shortage designation for FQHCs. This allowed FQHCs to be designated as Health Professional Shortage Area (HPSA) facilities, thereby permitting participation in the National Health Services Corps program. Despite implementation of this additional support for FQHCs, access to oral health care continues to be a challenge for the most vulnerable children. Although FQHCs are an important part of the safety net, they do not have the capacity or efficiency of private dental offices. Indeed, the CHIP reauthorization law of 2009 gives FQHCs the authority to contract out to private dental providers. The AAPD recommends that FQHCs use the option to contract with private practice pediatric dentists, and this approach be vigorously promoted by the Health Resources and Services Administration (HRSA).

The AAPD strongly supports Expanded Function Dental Auxiliaries (EFDAs) to improve dental practice efficiency and expansion of services to more patients. However, other models are promoted in the IOM report without evidence they would have an impact on improving access to care. See the AAPD’s Policy on workforce issues and delivery of oral health care services in a dental home:

Every child deserves a dentist, and all children deserve equal and optimal oral health care at the highest standard. While the AAPD advocates for appropriate preventive counseling and intervention by physicians and other non-dentist providers, such efforts need to be in tandem with the establishment of a Dental Home.

The American Academy of Pediatric Dentistry

Founded in 1947, the AAPD is a not-for-profit membership organization representing the specialty of pediatric dentistry. AAPD’s 8,000 members are predominately pediatric dentists and primary care providers who deliver comprehensive specialty treatments for infants, children, adolescents and individuals with special health care needs. As advocates for children’s oral health, the AAPD aims to promote the use of evidence-based policies and guidelines, foster research concerning pediatric oral health, and educate health care providers and the public to improve children’s oral health.

(1) Decker S, Medicaid payment levels to dentists and access to dental care among children and adolescents, JAMA 2011; 306:187-193.

Millions of Americans Lack Access to Essential Oral Health Care


Millions of Americans are not receiving needed dental care services because of "persistent and systemic" barriers that limit their access to oral health care, says a new report by the Institute of Medicine and National Research Council. To remove these barriers -- which disproportionately affect children, seniors, minorities, and other vulnerable populations -- the report recommends changing funding and reimbursement for dental care; expanding the oral health work force by training doctors, nurses, and other nondental professionals to recognize risk for oral diseases; and revamping regulatory, educational, and administrative practices.

"The consequences of insufficient access to oral health care and resultant poor oral health -- at both the individual and population levels -- are far-reaching," said Frederick Rivara, Seattle Children's Guild Endowed Chair in Pediatrics at the University of Washington School of Medicine, Seattle, and chair of the committee that wrote the report. "As the nation struggles to address the larger systemic issues of access to health care, we need to ensure that oral health is recognized as a basic component of overall health."

The report says that economic, structural, geographic, and cultural factors contribute to this problem. For example, approximately 33.3 million people live in areas with shortages of dental health professionals. In 2008, 4.6 million children did not obtain needed dental care because their families could not afford it. And in 2006, only 38 percent of retirees had dental coverage, which is not covered by Medicare.

Lack of regular oral health care has serious consequences, the report says, including increased risk of respiratory disease, cardiovascular disease, and diabetes, as well as inappropriate use of hospital emergency departments for preventable dental diseases. The report offers a vision of oral health care in which prevention of oral diseases and promotion of oral health are a priority and a facet of overall health.

Although all states must provide comprehensive dental benefits for children enrolled in Medicaid or the Children’s Health Insurance Program (CHIP), they are not required to provide such benefits for adults. Because publicly funded programs are the primary source of health coverage for underserved populations, including dental benefits for all Medicaid beneficiaries is a critical and necessary goal, the report says. Toward that end, the committee recommended that the Centers for Medicare and Medicaid Services fund and evaluate state-based demonstration projects that cover essential oral health benefits for adult Medicaid beneficiaries. In addition, Medicaid and CHIP reimbursement rates for providers should be increased and administrative practices need to be streamlined to increase use by both dental providers and patients.

To maximize access to oral health care, state legislatures should amend existing laws so that hygienists, assistants, and other dental professionals can practice to the full extent of their training and can work in a variety of settings under appropriate evidence-based levels of supervision. In spite of national accreditation standards for education and training of oral health professionals, regulations defining supervision and scope-of-practice parameters vary widely from state to state and even by procedure. Legislation should also allow dental professionals to collaborate and supervise remotely via conferencing technology.

The uneven distribution of the dental work force, both in geographic dispersion as well as in specialization, is a long-recognized challenge, the report notes. In addition, graduating dental students report that they feel unprepared to care for older patients and those with special needs.

The report says that efforts should be made to increase recruitment and support for dental students from minority, lower-income, and rural populations, as well as to boost the number of dental faculty with expertise caring for underserved and vulnerable populations. In addition, the Health Resources and Services Administration should dedicate Title VII funding to aid and expand opportunities for dental residencies in community-based settings. These residencies should take place in geographically underserved areas and include clinical experiences with young children, individuals with special health care needs, and older adults.

Thursday, July 14, 2011

Rapid prototyping comes to dentistry


Printing teeth

What if, instead of waiting days or weeks for a cast to be produced and prosthetic dental implants, false teeth and replacement crowns to be made, your dentist could quickly scan your jaw and "print" your new teeth using a rapid prototyping machine known as a 3D printer?

Researchers in Iran explain how medical imaging coupled with computer-aided design could be used to create a perfect-fit blueprint for prosthetic dentistry, whether to replace diseased or broken teeth and jaw bone. The blueprint can then be fed into a so-called 3D printer to build up an exact replica using a biocompatible composite material. Such technology has been used in medical prosthetics before, but this is an early step into prosthetic dentistry using rapid prototyping.

Writing in the International Journal of Rapid Manufacturing, mechanical engineer Hossein Kheirollahi of the Imam Hossein University and colleague Farid Abbaszadeh of the Islamic Azad University, in Tehran, Iran, explain how current technology used to convert an MRI or CT scan into a prosthetic component requires milling technology. This carves out the appropriate solid shape from a block of polymer but has several disadvantages, uppermost being that it is very difficult to carve out a complex shape, such as a tooth. By contrast, rapid prototyping uses a 3D image held in a computer to control a laser that then "cures" powdered or liquid polymer. Almost any solid, porous, or complicated shape can be produced by this 3D-printing technology.

The Iranian team has now demonstrated how rapid prototyping can be used to fabricate dental objects such as implants and crowns quickly and easily even where features such as overhangs, sharp corners and undercuts are required. The team points out that the most appropriate medical imaging technology, CBCT (cone-beam computed tomography), which is lower cost and exposes the patient to a lower dose of ionizing radiation is best suited to the generation of the computer design for creating such dental objects ready for printing.

Dentists can identify people with undiagnosed diabetes


In a study, Identification of unrecognized diabetes and pre-diabetes in a dental setting, published in the July 2011 issue of the Journal of Dental Research, researchers at Columbia University College of Dental Medicine found that dental visits represented a chance to intervene in the diabetes epidemic by identifying individuals with diabetes or pre-diabetes who are unaware of their condition. The study sought to develop and evaluate an identification protocol for high blood sugar levels in dental patients and was supported by a research grant from Colgate-Palmolive. The authors report no potential financial or other conflicts.

"Periodontal disease is an early complication of diabetes, and about 70 percent of U.S. adults see a dentist at least once a year," says Dr. Ira Lamster, dean of the College of Dental Medicine, and senior author on the paper. "Prior research focused on identification strategies relevant to medical settings. Oral healthcare settings have not been evaluated before, nor have the contributions of oral findings ever been tested prospectively."

For this study, researchers recruited approximately 600 individuals visiting a dental clinic in Northern Manhattan who were 40-years-old or older (if non-Hispanic white) and 30-years-old or older (if Hispanic or non-white), and had never been told they have diabetes or pre-diabetes.

Approximately 530 patients with at least one additional self-reported diabetes risk factor (family history of diabetes, high cholesterol, hypertension, or overweight/obesity) received a periodontal examination and a fingerstick, point-of-care hemoglobin A1c test. In order for the investigators to assess and compare the performance of several potential identification protocols, patients returned for a fasting plasma glucose test, which indicates whether an individual has diabetes or pre-diabetes.

Researchers found that, in this at-risk dental population, a simple algorithm composed of only two dental parameters (number of missing teeth and percentage of deep periodontal pockets) was effective in identifying patients with unrecognized pre-diabetes or diabetes. The addition of the point-of-care A1c test was of significant value, further improving the performance of this algorithm.

"Early recognition of diabetes has been the focus of efforts from medical and public health colleagues for years, as early treatment of affected individuals can limit the development of many serious complications," says Dr. Evanthia Lalla, an associate professor at the College of Dental Medicine, and the lead author on the paper. "Relatively simple lifestyle changes in pre-diabetic individuals can prevent progression to frank diabetes, so identifying this group of individuals is also important," she adds. "Our findings provide a simple approach that can be easily used in all dental-care settings."

Tuesday, July 12, 2011

Higher Medicaid payments to dentists associated with increased rate of dental care among children


Children and adolescents from states that had higher Medicaid payment levels to dentists between 2000 and 2008 were more likely to receive dental care, although children covered by Medicaid received dental care less often than children with private insurance, according to a study in the July 13 issue of JAMA.

According to background information in the article, more than one-third of children are covered by public health insurance, primarily Medicaid and the Children's Health Insurance Program (CHIP). Coverage of dental care for children and adolescents covered by Medicaid and CHIP is required, although states have wide latitude in setting payment rates for providers including dentists, with these rates varying greatly by state. Medicaid recipients may not be able to access dental care if dentists decline to participate in Medicaid because of low payment levels or other reasons. Little is known about the effect of state dental fees on participation of dentists in the Medicaid program.

Sandra L. Decker, Ph.D., of the Centers for Disease Control and Prevention, Hyattsville, Md., conducted a study to examine the association of state Medicaid payment rates for dental care with the receipt of dental care among children covered by Medicaid. The study included data on Medicaid dental fees in 2000 and 2008 for 42 states plus the District of Columbia, and these data were merged with data from 33,657 children and adolescents (ages 2-17 years) in the National Health Interview Survey (NHIS) for the years 2000-2001 and 2008-2009.

Of the 42 states plus the District of Columbia considered in the analyses, the 2008 Medicaid dental fees were lower than the (inflation-adjusted) 2000 fees in 23 states. Payment levels to dentists in 2008 were higher than in 2000 in 19 states plus the District of Columbia. In five states (Connecticut, Indiana, Montana, New York, and Texas) plus the District of Columbia, payments increased by at least 50 percent between 2000 and 2008.

The researchers found that the probability that a child or adolescent had seen a dentist in the past 6 months varied by insurance source. In 2008-2009, children and adolescents covered by Medicaid were less likely (55 percent) than children with private insurance (68 percent) to have seen a dentist in the past 6 months, but were more likely to have seen a dentist than children or adolescents without insurance (27 percent). According to the author's, "children were about 6 percentage points more likely to have seen a dentist in 2008-2009 than in 2000-2001. … Those covered by Medicaid or CHIP were about 13 percentage points and uninsured children were about 40 percentage points less likely than children with private insurance to have seen a dentist."

"Changes in state Medicaid dental payment fees between 2000 and 2008 were positively associated with use of dental care among children and adolescents covered by Medicaid. For example, a $10 increase in the Medicaid prophylaxis payment level (from $20 to $30) was associated with a 3.92 percentage point increase in the chance that a child or adolescent covered by Medicaid had seen a dentist," the authors write.

"As future expansions in Medicaid eligibility and insurance coverage more generally are contemplated and possibly implemented, more attention to the effects of provider payment policies on access to care, quality of care, and health outcomes may be warranted."

Wednesday, July 6, 2011

Dentists are a major source of opioid drugs

With a cover article in the July edition of the Journal of the American Dental Association (JADA), dentists focus that spotlight on themselves both as major sources of opioid drugs and as professionals with largely untapped power to recognize and reduce abuse.

“Many dentists really haven’t even perceived there to be a problem,” said George Kenna, an assistant professor of psychiatry and human behavior at the Warren Alpert Medical School of Brown University, an addiction psychologist at the Center for Alcohol and Addiction Studies, and the corresponding author of the article. “Dentists write the third-most prescriptions for immediate release opioids in the United States, but they often don’t know the appropriate number of doses to prescribe, how many doses a patient uses, or most importantly what patients do with the leftover tablets they have. Just ask someone the last time they threw away opioid prescriptions in particular. These leftover tablets — accumulated from various sources, not just dentists — that are often left in closets across the country are the primary source for prescription drug use initiation for children and adolescents.”

Last year Kenna helped lead a meeting of dentists and fellow addiction experts and pharmacists at the Tufts Health Care Institute Program on Opioid Risk Management, where he serves as a scientific adviser. The group produced this month’s cover article for JADA, which offered several recommendations for dentists, including:

• Discuss with patients whether they need an opioid for their pain and how likely they are to use what you prescribe.
• Consider writing small quantities and limit refills.
• Do not prescribe drugs to patients you do not know; be suspicious of those who claim their drugs were lost or stolen.
• Use prescription monitoring programs (i.e., state databases), if available, to verify drug-use history.
• Advise patients either to destroy or lockup any excess medication.
• Keep prescription pads locked up.

In the article, the nine authors also call for more research to make the most effective use of opioid and non-opioid painkillers, for instance to determine how much painkiller and which kind patients really need. Without enough evidence to guide them, dentists have often felt obliged to prescribe opioids too often and in too great a quantity, Kenna said.

“Some new data show that ibuprofen as an anti-inflammatory does as well as many painkillers to kill pain for many dental procedures,” Kenna said.

One in two dentists surveyed

Despite the large role dentists have as painkiller prescribers, there has been very little research on dentists’ prescribing practices and experiences, particularly in the context of opioid addiction. To inform their discussion, the group commissioned a survey in 2010, led by Michael O’Neil, a pharmacy professor at the University of Charleston in West Virginia. In all, 52 percent of the state’s dentists responded.

The survey revealed that nine in 10 of the dentists surveyed prescribed opioids in the prior year. Two-thirds prescribed between 10 and 20 doses of the painkillers, but 41 percent acknowledged that patients would probably have some left over.

The survey also found some evidence that dentists can sometimes be shy about raising substance abuse as an issue with patients, even as they realize they are sometimes being used to get drugs. One in three of the dentists said they did not routinely ask new patients about substance abuse, but 58 percent of the dentists said they believed they have been the victim of prescription fraud or theft.

While dentists should guard against over-prescribing addictive drugs, especially to patients they don’t know well, Kenna said, they retain an obligation to help all patients, even ones who are addicted, to manage pain.

“There are ways that dentists can work with patients,” he said. “People who have a substance abuse problem do have legitimate pain. They do have a right to have some pain control and may even need more. But you hope there is a family member who will take control and make sure they only take the recommended dose.”

For all the things dentists could do, especially with more research to clarify the best prescribing practices, Kenna acknowledged that dentists are not currently compensated for the time required to investigate the drug use preferences and habits of their patients.

Kenna said he hopes to learn more about how the profession approaches opioids and addiction with a national survey of dentists.

“It’s a growing problem in the United States,” he said. “It’s a serious problem.”

Gum disease can increase the time it takes to become pregnant


For the first time, fertility experts have shown that, from the time that a woman starts trying to conceive, poor oral health can have a significant effect on the time to pregnancy.

Professor Roger Hart told the annual meeting of the European Society of Human Reproduction and Embryology that the negative effect of gum disease on conception was of the same order of magnitude as the effect of obesity.

Periodontal (gum) disease is a chronic, infectious and inflammatory disease of the gums and supporting tissues. It is caused by the normal bacteria that exist in everyone's mouths, which, if unchecked, can create inflammation around the tooth; the gum starts to pull away from the tooth, creating spaces (periodontal pockets) that become infected. The inflammation sets off a cascade of tissue-destructive events that can pass into the circulation. As a result, periodontal disease has been associated with heart disease, type 2 diabetes, respiratory and kidney disease, and problems in pregnancy such as miscarriage and premature birth. Around 10% of the population is believed to have severe periodontal disease. Regular brushing and flossing of teeth is the best way of preventing it.

Prof Hart, who is Professor of Reproductive Medicine at the University of Western Australia (Perth, Australia) and Medical Director of Fertility Specialists of Western Australia, said: "Until now, there have been no published studies that investigate whether gum disease can affect a woman's chance of conceiving, so this is the first report to suggest that gum disease might be one of several factors that could be modified to improve the chances of a pregnancy."

The researchers followed a group 3737 pregnant women, who were taking part in a Western Australian study called the SMILE study, and they analysed information on pregnancy planning and pregnancy outcomes for 3416 of them.

They found that women with gum disease took an average of just over seven months to become pregnant – two months longer than the average of five months that it took women without gum disease to conceive.

In addition, non-Caucasian women with gum disease were more likely to take over a year to become pregnant compared to those without gum disease: their increased risk of later conception was 13.9% compared to 6.2% for women without gum disease. Caucasian women with gum disease also tended to take longer to conceive than those who were disease-free but the difference was not statistically significant (8.6% of Caucasian women with gum disease took over one year to conceive and 6.2% of women with gum disease).

Information on time to conception was available for 1,956 women, and of, these, 146 women took longer than 12 months to conceive – an indicator of impaired fertility. They were more likely to be older, non-Caucasian, to smoke and to have a body mass index over 25 kg/m2. Out of the 3416 women, 1014 (26%) had periodontal disease.

Prof Hart said: "Our data suggest that the presence of periodontal disease is a modifiable risk factor, which can increase a woman's time to conception, particularly for non-Caucasians. It exerts a negative influence on fertility that is of the same order of magnitude as obesity. This study also confirms other, known negative influences upon time to conception for a woman; these include being over 35 years of age, being overweight or obese, and being a smoker. There was no correlation between the time it took to become pregnant and the socio-economic status of the woman.

"All women about to plan for a family should be encouraged to see their general practitioner to ensure that they are as healthy as possible before trying to conceive and so that they can be given appropriate lifestyle advice with respect to weight loss, diet and assistance with stopping smoking and drinking, plus the commencement of folic acid supplements. Additionally, it now appears that all women should also be encouraged to see their dentist to have any gum disease treated before trying to conceive. It is easily treated, usually involving no more than four dental visits.

"The SMILE study was one of the three largest randomised controlled trials performed in Western Australia. It showed conclusively that although treatment of periodontal disease does not prevent pre-term birth in any ethnic group, the treatment itself does not have any harmful effect on the mother or foetus during pregnancy*."

Prof Hart said that the reason why pregnancies in non-Caucasian women were more affected by gum disease could be because these women appeared to have a higher level of inflammatory response to the condition.