Tuesday, 21 August 2012

Dental heath, dental care and dementia

Regularly cleaning your teeth and keeping your gums healthy could help lower your risk of succumbing to dementia later in life, according to a recent US study.

Researchers at the University of California collected health data regarding the dental health and dental habits of over 5000 individuals living in a large retirement community over a period of 18 years. The participants of the study were all dementia free at the outset of the study in 1992, and of them, around 27% were diagnosed with dementia by 2010.

The results were interesting. The individuals with teeth, who did not brush their teeth daily were up to 65% more likely to develop dementia than those who brushed multiple times a day - although this link was only statistically significant in women. Not visiting the dentist regularly (i.e. a lack of dental upkeep and supervision) was also associated with an increased dementia risk.

Although this study is limited and does not establish an explicit causal link between dental health and dementia, it could suggest that 'retaining adequate masticatory function through regular oral hygiene and use of dentures may reduce risk of dementia' (Paganini-Hill et al. 2012), with further studies required to identify exactly how and why dental health and dementia are connected.

There are certainly mechanisms by which such a link could exist. For example, the brains of Alzheimer sufferers have been found to contain more species of the oral Treponema bacteria than the brains of control groups. This may indicate that it is partly or occasionally the inflammatory responses of the body and brain to these pathogens which are responsible for illness.

In the context of the ever-ageing populations of the developed world, it's probably a good call to investigate the associations between dental and overall health - after all, keeping an elderly population in tip-top mental shape might be as simple as promoting a holistic approach to health - which includes regular tooth brushing!

Paganini-Hill, A. et al. 2012. Dentition, Dental Health Habits, and Dementia: The Leisure World Cohort Study. In the Journal of the American Geriatrics Society, Volume 60, Issue 8
Available here. 

Friday, 10 August 2012

Teeth where teeth should not be...

After 23 years of abnormal swelling in her left eye, Nagabhushanam Siva decided to let doctors in Chennai, southern India investigate her condition.  A tumour was diagnosed and an operation was undertaken, only to reveal the presence of two fully formed teeth within the tumour itself. Unfortunately, the tumour had been in place for too long, placing pressure on the optic nerve and leaving it permanently damaged - thus the operation was not successful, leaving Siva blind.

Teeth in the tumour, seen during surgery.
(Cover Asia Press)
This kind of tumour is usually present from birth and is called a 'mature teratoma'*. Disturbingly, they can contain all sorts of misplaced tissue - including hair, teeth and bone. In some cases, the growth can include even more complex organs. As I discovered with not a small amount of horror that such a thing as an 'mature ovarian cystic teratoma' can exist. This is often a mass of disorganised tissue within the ovarian region, but can occasionally form into a 'homunculus' with a generalised human form. In one case study from Japan, such a tumour was found to have 'Brain, eye, spinal nerve, ear, teeth, thyroid gland, bone, bone marrow, gut, trachea, blood vessels, and phallic' tissue (Kuno et al. 2003), arranged in a 'well organised' fashion.

Although such tumours are rare, they contain skeletal and dental tissues which could very well survive in archaeological contexts. A brief search of the International Journal of Osteoarchaeology hasn't turned up any clear examples of such a condition in the past, but I think they could be out there. It's certainly something to keep in mind next time I find some teeth where teeth really shouldn't be...

* Wikipedia informs me that a benign tumour of this nature, in the UK is termed a 'mature teratoma', whilst in the US it's simply referred to as a teratoma. In the UK, a 'teratoma' or 'immature teratoma' refers to a malignant tumour.