Julian Huxley is a new patient in your practice. What is his condition?
He finds it extremely difficult to maintain oral hygiene - why? How would you help Julian?
His mother is pregnant with her second child, and is very worried that it may have teeth like Julian's. What advice can you offer?

ABFRACTION

It was Grippo(1991) who coined the term abfraction to describe the pathological loss of enamel and dentine caused by biomechanical loading of teeth. He stated that the forces could be static, such as those produced by swallowing and clenching; or cyclic, as in those generated during chewing. He suggested that non-carious cervical abfractive lesions were caused by flexure and ultimate material fatigue of susceptible teeth at locations away from the point of loading. Grippo thought that the breakdown was dependent on the magnitude, duration, direction, frequency and location of the forces. (Grippo JO 1991 Abfraction: a new classification of hard tissue lesions of teeth. J Esth Dent, 3:14-8).
Examine the three figures given.
• Comment on the clinical picture. How would you diagnose an abfractive lesion? Can you see any in this case? If there were any, how would you treat them?
• Now examine the two SEM images. What are A, B & C? Comment on the differences between A, B & C in the two figures. What is happening here?

Mastication

Mastication is a rhythmic movement regulated by a central pattern generator that is sensitive to and dependent on oral sensory feedback. Mastication is therefore continually modified throughout the chewing sequence in response to the texture of the food bolus. The effect of food texture on masticatory parameters has, however, not been systematically studied. The main obstacle is that food is a complex stimulus that is difficult to reduce to a single physical dimension.
Mastication is also continually modified throughout the chewing sequence in response to the texture of the food. The aim of our work is to compare the effects of an increase in hardness of two model food types, presenting either elastic or plastic rheological properties, on mastication. We intend testing this in our robotic jaw (Picture)
What do you think of this model?
How would you determine the effect of food properties on the mastication of this artificial jaw?
How would you construct the jaw?
If you are interested in it, maybe let us have your views!
A good article is by one of our collaborators, Kylie Foster:
J Neurophysiol 95: 3469-3479, 2006
K. D. Foster, A. Woda and M. A. Peyron

Forensic dentistry

The estimation of age at death from human skeletal remains is a critical aspect in the reconstruction of a biological profile in both forensic and archaeological contexts. Moreover, both in forensic medicine and in the clinical setting, there is a growing demand by courts for appropriate estimations of age in living subjects suspected of being minors without documentation. In juvenile forensic cases, age estimation may rely on an evaluation of skeletal maturation, dental eruption or on tooth formation.
Which of these do you think is the method most frequently used?
Which is arguably the most reliable method?
Why would this be?
Look carefully at the images of the child and try and work out how old it was.

Bell's Palsy

Facial nerve paralysis is a devastating problem for those affected. Few areas in dental neurology have been as controversial as the management of Bell's palsy. The past several decades have witnessed many theories about the etiology and pathogenesis of Bell's palsy. In concert with each of these theories has been an appropriate management scheme. Because of the nature of the literature, it has been difficult for clinicians to unequivocally outline management algorithms.
Think about the causes of Bell's and then try and work out how you would treat a patient with Bell's. Specifically, lets hear your thoughts on:

• The management of drooling
• Masticatory problems
• Speech problems
• Swallowing
• eye problems.
  

Ectomesenchyme

The development of the human face involves extremely complex morphogenetic processes. Several congenital anomalies of the face, including Treacher Collins Syndrome and Cleft Lip and Palate CL[P] are related to the behaviour of neural crest NC cells. Things to think about are:

* The origin of of NC cells
* Pathways of migration
* What happens during migration, ie is this a stable or susceptible period?
* Targets of migration
* What can affect migration? (think of Retinoic acis, ethanol etc).

Look at the figure below and try and remember how clefting of the lip develops. Can you remember when? What is the role of apoptosis here? What dietary factor stabilizes the process? Which ethnic group is most susceptible to CL? Why?
Try and download the article and let me have your comments. Its an old article, so you might want to look at more recent stuff. Post the references here if you find something you think we can learn from.