21 Apr Imagine A Dental Handpiece That Never Breaks
Overnight, the dental handpiece repair industry was created in the USA exposing new problems for dentists. The origins of the industry are in the 1950’s when the sterilization of dental instruments and tools was mandated. Previous to sterilization, handpieces were virtually un-breakable and effortless to care for. In this article we look to illustrate why the dental sterilizer decreased reliability of the handpiece and what measures can be taken to reverse the impact a sterilizer has on the life of a handpiece.
A dental sterilizer is essential for minimizing cross-contamination between patients. The most common form of sterilizer used in dentistry is a steam sterilizer which works by “exposing each item to direct steam contact at the required temperature and pressure for a specified time (CDC.gov).” The active agents of steam sterilization, heat and pressure have devastating impact on the moving components of a dental handpiece making periodic failure inevitable. By learning how each component reacts to the sterilization process and combatting the causes of failure allows dentists to wind back the clock and minimize the agony of handpiece failure.
A dental handpiece only has one moving component, called the turbine, which is responsible for all its’ failures including symptoms such as wobbling, loss of torque, squealing, or the locking or dropping of burs. Each of these symptoms will render a handpiece useless delaying daily work, losing money, and losing time. Let’s first understand how these problems occur to then optimize future performance and reliability of every handpiece.
I am going to group wobbling and loss of torque into a single category because they occur simultaneously. The problem being experienced in this situation is the bearings within the turbine are beginning to fail or have failed. Dental bearings come in all shapes, sizes, and quality levels so it is important to understand how dental bearings function and which style of bearing will create a positive impact for your practice. A dental bearing has an inner and outer race which are stainless steel that allow the balls within the bearing to spin; the part that holds the balls equidistance from each other and in line is called a retainer. The only thing that can break on a dental bearing is the retainer which is made from a phenolic (nylon) or torlon (textile) material. Many people over the years have lost focus of the importance of this retainer, instead focusing on the balls (ceramic or stainless steel) which in reality have a negligible impact on bearing life. During the sterilization process, the retainer becomes very dry is at its highest risk of breaking. The heat alone cannot break the retainer but when the bearings are used in this dry state, the probability of the retainer breaking is high. This is why oil is used before and after the sterilization process to make sure the retainer does not get to a dry, brittle state decreasing the chance of failure.
When the sterilizer was created, the only retainer available for dental bearings was a torlon (textile) retainer. The material has proven itself over the years to be durable, but it has a limited ability to retain oil between uses and sterilization cycles making oiling consistency very important for each sterilization process. A secondary material being used in retainers developed by Star Dental in the 1990’s is called phenolic. This material is made from compressed nylon and contains the ability to soak-up or retain small quantities of liquids such as grease or lubricants. Star Dental originally called the bearing lube-free because they packed it with a grease during the manufacturing process which is retained and slowly expelled through the bearings life-span allowing the retainer to stay moist during sterilization. Today, torlon retainers are the most common style of retainer being used in repairs even with the emergence of phenolic material. You must know what retainer is contained within your handpieces so you can understand the risks are associated with how you lubricate and care for each handpiece.
Another common problem that arises gradually between repairs is the decrease of gripping force the chuck or spindle has on the bur. The spindle is the center shaft of a turbine which the impeller and bearings are pressed onto to form a turbine. The only responsibility of a spindle is to accept, hold, then release a dental bur. Every handpiece and dental unit has a retraction valve that stops the flow of air when you release your foot from the rheostat. When this process occurs, dirt and debris from the procedure are sucked into the handpiece some of which are retained after usage. Anything that is retained inside the handpiece after a procedure goes into the sterilizer and bakes onto the inside of the handpiece and the components within. Over time, the moving parts within the spindle get coated with debris making the gripping function weak – it is like going to the park on a rainy day and playing football in the mud, if your hands are covered in water and dirt it becomes harder to catch the football. With a simple cleaning of the chuck (using a proxy brush) this debris can be cleaned out and any bur accepting or holding problems previously experienced will be solved. This procedure works only when the components are dirty and not broken which is roughly 75% of the time.
As a leading dental handpiece repair company, we feel that knowing your dental handpieces and how they react with modern sterilization processes is essential to the long-term health of your handpieces. It wasn’t long ago when handpieces were un-breakable and with the proper care, quality componentry, and understanding of the reasons for failure, your handpieces will perform and last like it was 1950 again.