What does the term rotary mean? ( Rotary is a part or device that rotates around an axis.) In dentistry, rotary instruments are attached to a handpiece. Rotary instruments operate at different speeds: high and low.
Rotary instruments were first introduced to complement hand instruments in the cutting, grinding, and polishing procedures of operative dentistry. Electricity is the power source for rotary instruments.
Who primarily uses the high-speed handpiece? ( Dentist. ) Who primarily uses the low-speed handpiece? ( Dentist, dental hygienist, and expanded-function dental assistant. ) Always refer to your state practice act before using a handpiece for treatment or operative procedures.
Also referred to as the straight handpiece because of its design. The low-speed handpiece is one of the most versatile handpieces in dentistry.
The straight attachment slides onto the low-speed motor and locks into place. What is the straight attachment commonly used for? ( Laboratory procedures, trimming removable prostheses such as dentures, partial dentures, flippers, and orthodontic retainers. )
Gloves, protective eyewear, mask, and appropriate garments must be worn during laboratory procedures .
What grasp is used with the straight attachment? ( Pen or palm grasp.) What grasp is used with the contraangle attachment? ( Pen or modified pen grasp.) The angled shank of the contraangle attachment provides ergonomic comfort. The operator can maintain proper neutral wrist position more readily during treatment procedures.
Polishing procedures include prophylaxis, tooth prep before placement of sealant, and amalgam polishing. What is an advantage of using disposable prophy angles in the dental office? ( Infection control. There is no need to clean and process the prophy angle for sterilization after use; simply dispose of the angle .) What is a disadvantage of using disposable prophy angles in the dental office? ( Cost. )
This slide shows disposable prophy angles, one containing a brush and the other containing a rubber cup. The brush is used to polish occlusal surfaces and lingual surfaces of anterior teeth. The rubber cup is used to polish smooth tooth surfaces.
The dentist uses the high-speed handpiece in every restorative procedure. What is the purpose of the water-coolant system? (The high-speed handpiece generates a significant amount of heat and friction as a result of the high number of revolutions per minute. The water keeps the tooth cool to help avoid injury to the pulp during preparation.) The fiberoptic light mounted in the head of the handpiece offers additional light to the operator and dental assistant during preparation of the tooth.
Unlike the low-speed handpiece, the high-speed handpiece does not have attachments. The only additional items placed in the high-speed handpiece are rotary instruments. What are these rotary instruments called? ( Dental burs. )
The high-speed handpiece rapidly removes diseased or decayed tooth structure. Often the dentist will refine the tooth preparation with the use of the low-speed handpiece after using the high-speed handpiece.
The American Dental Association Council on Dental Materials, Instruments, and Equipment evaluates professional scaling devices. Ultrasonic tips are classified as acceptable or provisionally acceptable. The ultrasonic handpiece uses mechanical radiant energy of water and sound vibrations to create a pulsating effect on a tooth surface.
There are three types of ultrasonic scalers: magnetostrictive, piezoelectric, and sonic. Magnetostrictive: Vibrations range from 24,000 to 42,000 cycles per second. Piezoelectric: Vibrations range from 29,00 to 50,000 cycles per second. Sonic (pictured on this slide): Vibrations range from 2500 to 7000 cycles per second.
The attachments for this handpiece are similar in design to hand (manual) scaling instruments. A specific tip is selected on the basis of the surface and the location of use.
Designed to perform special functions without changes and without damage to the surrounding tissues or materials. Caution must be used in handling the laser handpiece: Do not sharply bend the fiberoptic cord, do not touch the exposed fiberoptic cable, do not touch the end of the fiberoptic connector, and always keep the connecting parts clean.
Lasers are used in dentistry to remove decay from the tooth structure, to cure bonding materials, to whiten tooth teeth, and in periodontal treatment. Very specific equipment and training are required for the incorporation of laser technology into the dental office.
The air abrasion system was introduced to dentistry in the 1940s. It was originally designed to remove stain and tooth decay. Considered a patient-friendly approach to restorative treatment Permits the dentist to remove enamel, dentin, and restorative materials without compromising healthy tooth structure
One advantage to the use of the air-abrasion handpiece is that there is no need for local anesthesia. One disadvantage is the possibility of soft-tissue (gingiva) damage if incorrect techniques are used.
What is torque? ( A twisting or turning force.) Increased torque is better suited to the heavier pressure required during grinding and polishing procedures performed outside the mouth.
What are the main reasons a handpiece fails or breaks? (Improper cleaning and lubrication.) Inadequate cleaning of the handpiece before sterilization can result in the collection of debris in the handpiece’s internal parts. Debris creates wear on the handpiece motor and inner movable parts. Is it possible to lubricate a handpiece too much? ( Yes. Too much lubrication can be as damaging as not enough lubrication.)
Rotary cutting instruments are accessories intended for use with the dental handpiece. There are hundreds of different types of rotary instruments available in dentistry, and each is designed for a different task or use. It is important that the dental assistant know the dentist’s preferences.
Looking at the slide, what part makes up the largest section of the rotary instrument? ( Shank. ) The shank length will vary according to the specific function of the bur and the handpiece to which it is attached.
A dental bur is classified as a “sharp.” Care must be taken when placing the bur on the handpiece and removing the bur after the procedure. Removal of a contaminated bur should be done while wearing heavy utility gloves. Burs come in a variety of shapes. The shape is commonly referred to as the “contour” or “design.” Burs are used to enter the tooth structure, remove decay, extend preparations, cut retention grooves, form internal walls of the prep, and provide angles to the wall prep.
Finishing rotary burs are similar in appearance to cutting burs except for one distinctive feature. What is that feature? ( The number of blades or flutes is increased on the finishing bur.) The greater the number of cutting surfaces, the greater polishing capability. The slide pictures the three most common finishing burs: round, tapered and flame-shaped.
Numerous abrasive materials are found on these instruments, from very coarse to fine. Abrasive discs and wheels are attached to a mandrel (a metal shaft), which is then attached to the dental handpiece.