Estimated reading time: 6 minutes
From exploring early childhood interventions to better care for aged care patients, Dr Diep Ha’s research reaches across life stages in the search for better oral health outcomes for the most vulnerable. By Shane Conroy
Dr Diep Ha has dedicated her career to understanding and addressing oral health disparities among vulnerable populations. Her recent recognition as the 2024 IADR John Clarkson Fellowship winner is a testament to her impactful research on early-life determinants of oral health, fluoride use, and dietary patterns, and how they contribute to socio-economic inequalities over a lifetime.
Brisbane-based Dr Ha is a mid-career researcher at the University of Queensland’s School of Dentistry and has made exceptional contributions to national population-based research programs in child oral health.
Her research is deeply rooted in the understanding that oral health begins long before a child ever visits a dentist. Principal among her research is the groundbreaking SMILE study, which has followed more than 2000 children from birth since 2013. It tracks how factors such as sugar consumption, fluoride exposure, and parental oral hygiene habits impact the participants’ long-term dental health. Dr Ha says one of the key goals of the ongoing study is to determine which specific factors, if modified, could lead to significantly lower rates of dental disease.
“We want to quantify the relationship between early-life social determinants and oral health, and explore intervention pathways,” she explains. “If we intervene in specific factors, such as early sugar intake, how much dental caries can we prevent?”
A major finding from the SMILE study highlights the direct link between early sugar intake and childhood dental caries, with the risk growing significantly as children age.
“If the child was exposed to sugar consumption, it definitely increases the risk of having more dental caries at two years old and at five years old,” Dr Ha explains. “The gap between those groups grows as the child gets older.”
We want to quantify the relationship between early-life social determinants and oral health, and explore intervention pathways. If we intervene in specific factors, such as early sugar intake, how much dental caries can we prevent?
Dr Diep Ha
This research is helping dentists and policymakers understand how to intervene early to potentially reduce the need for complex and costly treatments later in life. And while the SMILE study is now more than a decade old, Dr Ha and her team are currently preparing for the next stage with further funding to continue tracking participants into later childhood and adolescence.
“We hope to acquire more funding to keep going because maintaining a birth cohort study like this takes long-term engagement and commitment.”
Decoding the ‘F’ word
Another of the most significant areas of Dr Ha’s research in the SMILE study involves fluoride exposure and its role in reducing dental health inequalities. Her findings offer confirmation that fluoridated water can help narrow the gap in oral health disparities, particularly among lower-income and Indigenous populations.
“We found that water fluoridation reduces the gap in dental health inequality between lower and higher socio-economic groups,” she says. “The same is also true for Indigenous populations—our findings make it clear that fluoridation helps to mitigate disparities in oral health.”
Her research also addresses a long-debated question about breastfeeding and dental caries. While some studies have suggested that extended breastfeeding beyond 24 months could increase the risk of cavities, the study’s findings clarify that this only applies in non-fluoridated water areas.
“There were concerns that long-term breastfeeding might increase the risk of dental caries, but our study found that breastfeeding is safe, particularly in the Australian context where fluoridation is present,” she says.
One of the most striking findings from the study is that children with high sugar intake and limited fluoride exposure are 70 per cent more likely to develop cavities in their permanent teeth. This reinforces the idea that fluoride and dietary habits must be addressed together.
Dentists should be more involved in aged care settings. Having proper referral pathways and a structured approach to oral health in nursing homes will help prevent major complications.
Dr Diep Ha
“This shows that fluoridation acts as a protective factor, reducing the damage caused by sugar,” Dr Ha confirms.
However, one of the most persistent misconceptions Dr Ha encounters is the idea that fluoride negatively affects cognitive development. This is a concern she and her team directly addressed in their research.
“We focused on answering the question: Does water fluoridation impact a child’s IQ? Our research found that fluoridation at optimal levels is safe. It does not negatively impact cognitive development or social wellbeing.”
Oral health assistance for the elderly
While much of Dr Ha’s research has focused on early-life oral health, she is also working with her team to lead the fieldwork of a Medical Research Future Fund (MRFF) project aimed at improving dental care for aged care residents and people with disabilities—two of the most overlooked groups in oral health research.
One of the major challenges in aged care facilities is nursing staff are often too busy to prioritise oral health, which can lead to significant dental neglect. Her team’s research could transform how oral health is managed in nursing homes by modifications to the oral health assessment tool (OHAT) to better support aged care staff to quickly assess residents’ dental needs and establish clear referral pathways to dentists.
“The oral health assessment tool was designed to standardise the way oral health issues are identified in aged care settings,” Dr Ha explains. “We are modifying it to improve its application and ensure early intervention before serious complications arise.
“Dentists should be more involved in aged care settings. Having proper referral pathways and a structured approach to oral health in nursing homes will help prevent major complications.”
Fighting for the vulnerable
Dr Ha served as a chief investigator on three successful National Health and Medical Research Council (NHMRC) projects and one MRFF project, and has played a key role in research leadership, study design, and the development of new data collection instruments, such as questionnaires and oral epidemiological examination protocols.
Born in Vietnam, Dr Ha says much of her passion for oral health research was shaped by her early experiences in her birth country, where she worked as a pediatric dentist before transitioning into public health research. Her first exposure to large-scale research came when she participated in the National Oral Health Survey of Vietnam. This involved traveling to rural and remote areas where dental care was virtually non-existent.
“I saw many communities where people had almost no access to dental care,” she says. “In some areas, people had to walk two days just to get dental treatment. We trained nurses and community health workers to provide basic oral health care with the hope to prevent more severe conditions.”
Dr Ha left Vietnam to move to Australia in 2002 to complete her PhD in Oral Epidemiology at the University of Adelaide. “It was a challenging time,” she recalls.
“I was in a new country, with young children, studying, and trying to build my career all at once. However, I had support from my supervisor and new Australian friends, and I still remember and appreciate that to this day.”
In 2021, she embraced the opportunities at the University of Queensland, drawn by its focus on population oral health and its commitment to vulnerable communities. She now leads critical projects that will influence both public health strategies and everyday dental practice for years to come.
“The more I see these issues, the more I realise this is my path. My goal is to help bridge oral health disparities and make a real impact.”
