Remote-controlled mechatronic arm: ergonomic system used in dentristy.

Popa, Anca ; Argesanu, Veronica ; Jula, Mihaela 等

1. INTRODUCTION

As known, a bad design of subassemblies of the working area in a dental cabinet (Argesanu, 2004) facilitates the appearance of adverse effects on health. In order to diminish the appearance of professional diseases settling in and also in order to obtain high performances in diagnostic and the process of treatment of the dentist, a remote controlled arm system has been created to replace the dental lamp (Burdea, 2008). The remote-controlled arm was performed according to operator needs in terms of ergonomics, improving work conditions of the staff in the field of dental medicine.

The aim is to position the light beam of the dental operating light parallel with the viewing direction in order to obtain shadow free lighting and a good balance between lighting in the working field and in the mouth as a whole. This avoids the forming of shadows from the hands, teeth, lips and cheek on the working field. A dental operating light must be able to be positioned around the head of the dentist, before and sideward so that the light beam is running parallel to the viewing direction, with a maximal deviation of approximately 15[degrees], in all positions around the patient chair (between 8.30-15.30 o'clock).

To achieve this, the dental operating light needs to have 3 (orthogonal) axes which then enables the lamp to turn in all directions to achieve the desired position next to the head of the dentist and avoid placing the lighting rectangle obliquely over the face of the patient which is uncomfortable for him/her. It is necessary to have shadow free lighting in the mouth of the patient and to make it possible for the dentist to move with his head during treatment without forming shadows with his head.

The adjustment of the lamp around 3 axes has to be made in such a way that it can easily be carried out with a balanced movement, with one handle in an as low a position as possible.

The illumination should be continuously adjustable from 8000-25000 lux. The amount of lighting must be continuously adjustable in connection with the age, the antropometric dimensions of the dentist, the position of the working field, the colour matching, etc., in order to be able to work with a luminance between 200--2000 [cd.sup.2], with an optimum of 1000 [cd.sup.2]. A too high illumination level will reduce the visual acuity and cause fatiguing, glittering of instruments etc. (Virtanen, 2001)

Visual fatigue is manifested through symptoms felt in the struggle of the visual analyzer to clarify the picture by more or less effective adjusting. Visual fatigue refers to lighting conditions, working distances, to the repeated brilliance of violent contrasts of color, to prolonged exposure time. So the visual fatigue of the dentistry practitioner is due to inadequate illumination of the operating field, common visual adjustments, resulting from the incorrect operating acts. Other causes are related to accommodation disturbances and refractive disorders. General symptoms are periorbital, frontal temporal, occipital located headache, gastric disorders in the form of indigestion, dyspepsia, vomiting. Eye symptoms include the feeling of warm eyes and weight of the eyelids. Visual symptoms manifest in difficulties of distinguishing clearly the image, perception of color breakdown, diplopic, vertigo, disturbance of assessing spatial relationships.

2. REMOTE CONTROLLED MOBILE ARM. CONSTRUCTIVE AND FUNCTIONAL DESCRIPTION

2.1 General considerations

The proposed remote controlled mobile arm for the dental lamp improves the activity of the dentist, both in terms of ergonomics and technological points of view. The classic role of this lamp is to illuminate the oral cavity of the patient. The classic lamp troubles the patients comfort. The new solution proposes a lamp with more powerful lighting of the source, remote-controlled arm, image acquisition and reduced dimensions. This connected mobile device, focuses the light exclusively on the operating area. The spectrum of the emitted light will not affect patient comfort and have not any long-term effects on practitioners. Another device that was attached to the arm is a video camera that has the role of image acquisition, that will transmit the captured images via a monitor located ergonomically, according to the needs of the dentist (Atitoaiei & Argesanu, 2000).

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2.2 The device

The video-camera--type 208C Wireless Color CMOS Camera and Micro Receiver Set, provides a clear picture of the mouth cavity. The main features of the video camera are: wireless transmitting and receiving, compact size and low weight, low energy consumption, high sensitivity, easy maintenance, equipped with standard and easy to change lenses, wireless 120 W receiver, 9 V battery, video cable.

The advantage of the surveillance system consists of the increased emission from 50 to 250 mW. Audio-video signal provided by the receiver may be received or recorded by any system equipped with audio-video plug-ins: TV, surveillance monitor, VCR, MP4 Player, PC video capture card etc. In order to move the arm of the lamp it uses a DC motor, via remote control.

The image acquisition from the camera is via a radio receiver, which through manually adjustment obtains images from the camera. The reception device is located behind the screen, mounted on a timber support. The device is connected to the LCD screen, via two RCA plugs.

The picture reception is realised with a 7 inch LCD screen, which is connected to the radio receiver. The LCD screen is placed upon a mobile platform, with four degrees of freedom, being easily manipulated. The camera displays the image of the patient's mouth in real time, for a successful intervention.

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3. CONCLUSION

The concept of ergonomics is an existential matter, by which man interacts with the external environment and working environment from an emotionally and physically aspect, in a perfect harmony. The final argument is the comfort, health and maximizing work efficiency (Burdea, 2004). Devices and Electrical diagram of the whole video systems are subjected to the rigor of quality and function, which are designed so that the ergonomic issues, the working position, handling, to be as accurate as possible, with a special focus on the effects on the health of the human operator (Argesanu, 2004; Irimie, 2008).

Through its construction the device provides movement on 3 orthogonal axes thus avoiding shadows by focusing the light parallel with the viewing direction of the operator. The system provides easy maintenance, programming and accessibility.

Furthermore it zooms in on problem areas providing better focus for the dentist.

4. REFERENCES

Argesanu V. (2004). Ergonomics of medical equipment and departments, Ed. Eurostampa, Timisoara, 2004

Atitoaiei V., Argesanu V. s.a. (2000). Equipments for scenic illumination, Ed. Eurostampa, Timisoara, 2000

Burdea, et a. (2008). Robotic system for dental subtraction radiography. Proc. Of the IEEE Intl. Conference on Robotics and Automation, pp 2056-2062. Sacramento, USA, ISBN 0-8186-2163-X, 2008

Irimie, S. (2008). Ergonomie industriala. Ed AGIR. Bucuresti. 2008

Thornton, LJ., et. a. (2003). Physical and psychosocial stress exposures in US dental schools. The need for expanded ergonomics training. Applied Ergonomics, vol. 35, no. 2, 153-7, 2003

Virtanen, T. (2001). Ergonomic Survey of Dental Care. Proc. Of NES 33rd Annual Congress pp 398-401, ISBN 951-445222-4, Tampere, 2001