Dental instrumentation and maintenance (Proceedings)
As in human dentistry, veterinary dentistry uses a combination of power and hand instrumentation. Periodontal therapy and exodontics are the primary procedures done in the small animal practice. The technician's knowledge of the instruments needed for these procedures is crucial in order to quickly diagnose and treat the dental patient.
Periodontal diagnosis and therapyThe dental chart
The finding of the oral exam of the patient under anesthesia is recorded on the dental chart. The dental chart is a diagrammatic representation of the patient's dentition. Along with the diagram detailed notes need to be made. The dental chart can also be copied and sent home with the owner.
Parts of the instrument
Handle – The part that you hold in your hand
Shank – This is the segment that connects the handle to the working end
Working End – This is the blade or probe end that touches the tooth. It can be curved or straight. The amount of curve facilitates the use of the instrument in certain areas of the mouth and on certain aspects of the tooth.
Types of hand instruments
Scalers – This instrument has a sharp tip and three sharp edges. The blade can be straight or curved. If you look at the instrument with the tip pointing towards you, it looks like a triangle. It is used only for the removal of supragingival calculus. While there is a myriad of different types of scalers, the most common are the Townsend sickle, the Jacquette, and the Morse.
Curettes – This instrument has one or two sharp edges, a rounded back and a blunt tip or toe. They are used to remove calculus and debris from below the gumline both on the root surface called root planing, and to remove calculus and debris from the opposing surface of the gingival tissue called gingival curettage. The two most commonly used curettes are the Universal (Columbia, Barnhart) which can be used throughout the mouth and the Gracey which has one cutting edge and are area specific. The lower numbers are for incisors and canines and the higher numbers are used on premolars and molars.
Explorers – This instrument is used to examine the tooth surface. It's delicate and flexible steel tip is used to detect any abnormalities using the handlers sense of touch and/or hearing. The most common type of explorer is the Shepherd's hook. There is also a finer tipped explorer when you need more tactile sense to find smaller defects.
Periodontal Probes – This instrument is used to measure the depth of the gingival sulcus or it can measure gingival recession, which ascertains the stage of periodontal disease. Periodontal probes are calibrated in 1-3 mm intervals using notches or color changes.
Ultrasonic power scalers
Magnetorestrictive – This is the most commonly used scaler in practice. The insert fits into a handpiece. The insert is made up of stacked strips of laminated nickel or a ferroceramic rod a.k.a ferromagnetorestrictive. The metal strip insert vibrates causing the tip to move in an elliptical pattern. The ferromagnetorestrictive has a circular tip action. Water cools the tip by flowing into the handpiece and out through the tip. The magnetorestrictive operates at either 25 or 30 kHz. The ferromagnetorestrictive operates at 42 kHz.
Piezoelectric – This scaler has quartz crystals in the handpiece that expand and contract at a constant frequency. The tip has a back and forth motion and oscillates at 45 kHz. The tips screw into a metal base.
Because ultrasonic scalers operate at such a high frequency, they can generate significant heat. Leaving the tip on a tooth for too long or not having a constant water flow can cause thermal damage to the pulp. But when compared to the sonic scalers, the circular motion and the higher frequency decrease the working time.
Sonic scalers are usually air driven. The compressed air has a cooling effect and is also irrigated with water at the tip. Because of the presence of the compressed air, they are less likely to cause heat related damage to the teeth that the ultrasonic units can do. The water primarily flushes debris which allows for better visualization. These units operate below 20 kHz and at 30-40 psi of air pressure. The tips for these units also screw into a metal base in the handpiece.