It is a well-known fact that dental professionals are burdened with a field-specific risk of health problems related to their musculoskeletal system. As many as 86 percent of dentists experience neck and back pain annually.1 For this reason their work posture has been investigated in various studies, with the objective of optimising it in order to minimise the prevalence of such musculoskeletal problems.
While the dental chair and dental stool have been the subject of much study in this regard, the humble foot controller is rarely recognised as being associated with ergonomic considerations, despite its being in almost constant use during clinical procedures.
RESEARCHER SHEDS A NEW LIGHT
Dr Caroline Gerhard2 has confronted this omission in her dissertation on the effect of the operational principles of different types of dental foot controllers on spinal position and foot pressure distribution.
Her result: all of the foot controllers tested cause some degree of non-physiological posture in dentists, but XO CARE’s sliding rotation type works on the best (least harmful) operating principle (based on both measured results and the subjective perceptions of the volunteers).
A CLOSER LOOK AT THE STUDY
For the study, 63 candidates between the ages of 19 and 71 were divided into three equally sized groups. Subjects in group 1 had no medical experience, and as such had never used a foot controller. Group 2 consisted of students in their last year of study, or dentists with up to ten years of experience; while those in group 3 possessed a minimum of 10 and an average of 25.1 years of dental experience.
The change in spinal position during the use of a foot controller was registered using ultrasonic sensors attached to the volunteers’ skin. The distribution of foot pressure was measured using thin-shoe insoles in the volunteers’ shoes. The measurements were carried out with four different foot controllers, which share common functions, but differ in their operational principle.
The types of foot controller investigated were:
- the universal pedal controller
- the combined sliding pedal controller
- the pedal controller
- the XO CARE sliding rotation controller
THE FOOT AND ITS MOVEMENT
During the use of the universal pedal controller (1), the foot undergoes a bend (flexion) followed by a stretch (extension).
To actuate the combined sliding pedal controller (2), the foot must operate in a combined vertical and horizontal motion. During this motion, the foot is bent and applies pressure onto the pedal.
Operation of the pedal controller (3) requires multiple movements (flexion and extension) on a vertical axis, along with constant application of pressure.
When using the sliding rotation controller (4) the foot undergoes the least amount of movement. This happens primarily due to the horizontal foot movement, and the fact that the foot is on the floor most of the time. It has also the lowest pressure load of all the tested foot controllers.
As a consequence of the different types of movement involved, the first three foot controllers show significant differences in tension in the lumbar spine, while the sliding rotation type shows no change in this spinal area.
IT’S AS GOOD AS IT FEELS
To summarise the results of the study described, there is a link between the way in which the foot controllers work and the consequent changes in spinal position.
Interestingly, the volunteers participating in the test also received a questionnaire, in which they were asked to give their subjective impressions. Analysis of the results showed a correlation between the negativity of the volunteer’s reviews and the measured influence on spinal position. XO CARE’s sliding rotation controller not only had the best measured results, but was also described as the most comfortable to use.
1Meyer, V. P., Brehler, R., Castro, W. H. M., Nentwig, C.G. Arbeitsbelastungen bei Zahnärzten in niedergelassener Praxis. Köln, München 2001.
2Dissertation for Doctorate of Dentistry in the Faculty of Medicine at the Goethe University Frankfurt. “The effect of different operational principles of dental foot controllers on spinal position and foot pressure distribution”, presented by Caroline Gerhard, 2011.