Dental Chair

DENTAL CHAIR, is of great importance in the work of an odontologist for the correct positioning and fixation of the patient's head. Positioning consists of turning the head to one angle or another to the right or left with a certain inclination of the head forward or backward, namely: during manipulations on the lower jaw, the patient's chin is brought closer to the chest; when working on the upper jaw, it is tilted back slightly. During prolonged work in the oral cavity and on the teeth, a steady positioning of the head is possible only with a stable and comfortable position of the entire torso, arms, and legs of the patient. The patient acquires such a position in a dental chair. The design of the dental chair is calculated so that the doctor stands to the side of the patient, using light from a window or a reflector lamp located opposite the patient. For the first time, a dental chair appears in Europe in the 16th century in the form of a specially adapted chair with a headrest. At the present time, three main types of dental chairs are distinguished: 1) surgical dental chair, 2) dental chair with a screw lift, 3) dental chair with an oil pump (Figs. 1 and 2). In addition, there are various types of portable, mobile dental chairs used in conditions of mobile work or in a military setting. The most

[Figure] common and convenient is the dental chair with an oil pump. It consists of the following parts: headrest, backrest, seat, armrests, footrest, base, and pump. The headrest has the purpose of fixing the patient's head during manipulations in the oral cavity, which is especially important during tooth extraction, removal of dental calculus, and during other surgical operations, as well as in pediatric practice. The backrest has the purpose of creating a comfortable position and support for the patient's torso. The backrest can be given a different position depending on the height and

Figure 2.

figure of the patient and on the conditions of work in the oral cavity; in the latter case, it can be tilted back until it is brought into a horizontal position. The seat has the shape of a horseshoe and must be sufficiently comfortable for the patient's prolonged stay in the chair. The armrests are arranged with the calculation that during surgical operations they can be tilted and lowered, allowing the doctor to approach the patient closely. In some dental chairs, the tilting armrests are equipped with a metal rod, which, resting on the floor, turns the armrest into a chair for the doctor. The footrest contributes to creating a stable position for the patient in the dental chair. The lower part of the footrest is equipped with a device regulating the foot support for patients of different heights. The device for supporting children's feet is arranged under the seat, in the upper part of the footrest for adults. The base has a circular shape of a truncated cone with a wide foundation adjacent to the floor. The wider the base, the more stably the dental chair rests on the floor; however, it should not be too wide, as in the latter case it hinders the doctor from standing by the chair. Inside the base is placed an oil pump, single- or double-cylinder, with the help of which the seat of the chair together with the backrest and headrest is raised and lowered to the necessary height. The levers that set the various parts of the dental chair in motion are attached to the base. So-called clinical dental chairs have a backrest, seat, and sometimes a headrest made of polished wood; the armrests are made of metal and covered with enamel. In other cases, the headrests, seat, backrest, and armrests are covered with upholstery made of some fabric or leather. A dental chair with a screw lift differs little in design and purpose from a dental chair with an oil pump. In it, the seat is raised and lowered with the help of a screw fixed under the seat and rotating with the help of a gear transmission. Dental chairs of the field type are of very diverse design and are manufactured from various materials (wood, metal). The average weight of such a dental chair is from 18 to 45 kg. Dental chairs have been manufactured in the USSR since 1924.