Teaching extractions is no longer a pain

22 December, 2011 / Infocus

Extracting teeth was historically taught by an apprenticeship scheme and it wasn’t until the early 1700s that Paul Fauchard first published a book for dentists, which included a description of the stance and position that the operator should adopt. Something we still do today “plus ça change plus c’est la même chose”.

Teaching students how to extract teeth has progressed from a system that was, in essence, a continuation of the old hands-on apprenticeship to the present, where students are versed in the science behind their actions and practise on models before treating patients. Investigation into old Dundee Dental School student records, and interviews with retired dentists, produced an amazing level of undergraduate and postgraduate experience of tooth extraction. In the ’30s, one Dundee student took out 280 teeth in one month and in the ’60s a dental surgeon took out, from patients under general anaesthetic, 283 teeth in one day.

The number has fallen slowly over the years and the reasons are multiple. There is now better access to dental care in Tayside. Education, fluoride in toothpaste, recent celebrities’ tooth-whitening fads and the television programme ‘Ten Years Younger’ have, it would seem, all encouraged people in our catchment area to look after their teeth.

To teach the skill of extraction to students we have always needed a practice model. Talking to retired dentists at the Lindsay Society for the Study of the History of Dentistry, this model was the patient; with a lecturer literally hands-on guiding the student’s. Later, it was the pig’s head. The event, with all the cultural and aesthetic drawbacks, was memorable if only for the pungent odour of the heads on a warm day in the laboratory.

Frasaco produced replaceable metal teeth in a mannequin head, which was infinitely preferable. It was then easy to get the student and the forceps in the right place to do the deed. It gave a degree of realism but still did not have the feel of withdrawing the tooth from bone and, indeed, if the teeth were extracted from the mannequins, they wore out and were very expensive to replace. The models were very basic in form and this limited their use.

In Dundee University there is the Centre for Human Identification, under the direction of professor Sue Black. They have bodies donated for use in medical science, including training and research. Cadavers embalmed by the newly introduced Thiel method leaves them soft and supple, unlike the hard unyielding high formalin preserved ones that most will remember. You only have to shut your eyes to recall the nose-searing smell on entering the dissecting room for the first time.

Thiels have little smell. They have all the attributes of a live patient, the tissues are soft and easily retracted as in life. They have though, a strange appearance, reminiscent of an unfinished wax doll, in that all hair is lost during this process. There is a little degeneration in the perio membrane, too, but it’s not significant to our students’ experience of their first extraction. It does not make it easier to extract the teeth – as some of them found out when they fractured the roots.

However, another trial using Thiels for teaching minor oral surgery work found that the longer they had been embalmed the thinner and more tissue-paper like the mucosa became. It was not robust enough for students to manipulate and we still use silicon models for this. But despite this, the students could experience the hard tissue, bone cutting and tooth cleaving aspects of dento-alveolar surgery. The centre plans to change their embalming technique so that all bodies will be prepared in this way, but at present there were only sufficient numbers to allow a pilot study to appraise the value of Thiels as a teaching model for the staff and students. It was carried out this summer for the students who were to make the transition from books to clinic in the autumn. The students seemed at ease with the concept of working on the bodies. Only one out of 32 students did not want to extract a tooth.

Already, there is considerable experience in using these cadavers for all the basic dental local anaesthetic techniques. The local dissipates and can be given repeatedly. For the extractions, they were given a scenario for each case and encouraged to explain and interact with the Thiel as if it were a patient. It gave them the opportunity to begin to build an interactive script and develop their clinical manner, albeit with an unresponsive patient. They are usually so concerned with the mechanics of their first live extraction that conversation with the patient stalls and explanations to patients that they may experience deep pressure etc, becomes forgotten.

Feedback showed that those who did not have this primary introduction to extraction felt they were disadvantaged. Some would have liked to return after they had carried out their first in vivo extraction – “Why wouldn’t you want to practise?” was one comment. They wanted to ask more questions which might have been difficult in front of a patient and realised that the problems could be easily demonstrated on the Thiels. All students in the third BDS year, not only those that got this experience, seemed keen that it should be rolled out to all students in following years. It is possible that these bodies should be used for other post graduate procedures, for example implant placement. I have experienced implant courses that use isolated plastic mandibles but it is difficult to find the words without seeming to over exaggerate to emphasise how superior the bodies are.

As a lecturer I recognise that it is difficult to find a practise model that has translational validity and it has always been a tiring struggle to take mannequin theory into the clinic, but I was unprepared for just how good these bodies are for teaching. The ability to freeze-frame, intervene and correct with explanations, which would be entirely inappropriate in the clinical setting, was liberating.

Some with the Thiel experience agreed that it bolstered their confidence, which was just as well, for those who made this comment rated their confidence to carry out their first extraction on the low side. Would these have been the students who were so apprehensive that they would have dragged their heels to be among the last to extract teeth, and building up more of a psychological barrier to success as time went on? They have also said that they would love to have done more extractions and that the term should be a mix of live patients and Thiel bodies.

Over the years I have tried to produce realistic models for teaching. With the exceptions that the patient is not seated and there is a lack of interaction, these are my ideal bodies for teaching extraction techniques. It is a teaching opportunity not to be missed and I hope that we can extend this facility to all the undergraduates in the next academic year.

Professor Sue Black and her team, who some of you will remember from their television series, is running the somewhat unusual campaign ‘Million for a Morgue’ to raise money for building a modern morgue where all the bodies will be preserved in this way. The University of Dundee has earmarked £1 million to expand the centre for Anatomy and Human Identification (CAHID) and the campaign target is to match this.

Details of it can be found at http://www.millionforamorgue.com

About the author

Dr Christine J. Hanson, is a Lecturer/Associate Specialist in Oral Surgery at Dundee Dental School, Dundee University.

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