Thursday, March 2, 2023

The maintenance/ repair of dental handpieces

Dental handpieces used in dental clinics are precision micro-equipment. In use, in addition to daily disinfection of dental handpieces, correct use and maintenance are important measures for the normal work and prolongation of the handpiece's life; incorrect use will cause work Low speed, high noise and vibration, broken bearing ball frame, etc., greatly reduce the service life.

 

Proper use of dental handpieces

 

1 before use

(1) Before installing the dental handpiece, press the foot switch to spray out the remaining air and water in the tube, and observe whether the air and water are normal;

(2) install dental handpiece bur;

(a) Screw type: Install the dental handpiece on the treatment table, install the bur, and use the dental handpiece key to tighten it gently. Don't use too much force, just put it in place.

(b) Button type (gland type): press the button on the head of the dental handpiece to load and unload the bur, release the button, and the bur will be clamped. After installing the bur, check whether it is qualified by hand.

(3) Jog the foot switch to adjust the water to an appropriate flow rate and the air to an appropriate pressure. The standard pressure of the high-speed dental handpiece is between 0.2-0.25kgf/cm2.

( 4 ) Note: Before the dental handpiece is equipped with a bur, it is strictly forbidden to step on the foot switch, otherwise the three-leaf spring will rotate out, which will push against the back cover and both will be damaged.

2 in use

(1) When using the dental handpiece, it must be careful, meticulous, and light. It is strictly forbidden to operate brutally, and do not drop the dental handpiece to the ground.

(2) No matter what the angle is, it should be operated according to the way of lifting up and down, so as to achieve light touch and jog, and never use force from side to side.

(3) Use the improved pen grip to hold the dental handpiece, find a stable fulcrum, and perform intermittent operations.

(4) According to the different tooth positions and the different shapes of the prepared holes, replace the dental handpiece and bur in time to minimize the wear on the bearing of the dental handpiece.

(5) Sharp burs should be used. Blunt burs are not only time-consuming and labor-intensive, but also cause damage to the dental handpiece and increase the pain of the patient.

(6) During the use of the dental handpiece, always check whether the needle is loose to avoid flying burs.

(7) Choose different dental handpieces according to different clinical situations (for example, use a miniature handpiece that does not affect the line of sight for posterior tooth pulp opening; use a powerful high-torque handpiece for tooth preparation).

(8) The one-time workload is too large, and two dental handpieces should be used in turn to avoid damage to the dental handpieces due to excessive load, and to save time for replacing dental handpieces.

(9) The radial swing of the rotor of the dental handpieces is serious, and it is strictly forbidden to use it when it is moving longitudinally, and it is strictly forbidden to use the dental handpieces in an anhydrous or water-deficient state.

(10) The air pressure and water pressure will change with the use of the treatment table, so the air pressure and water pressure should be checked frequently during clinical operations to ensure the normal use of the dental handpieces.

Maintenance of dental handpieces

1 cleaning

After using the dental handpiece, it should be cleaned as soon as possible, otherwise the dirt will solidify and be difficult to clean. Before unloading the bur, clean debris from the working head with water mist, then scrub with 75% alcohol.

2 Take the bur

After use, you only need to loosen (turn) the key by 1/4 turn when removing the needle. If the key is too loose, the three-leaf spring will be pushed against the back cover and damaged. After each use, the burs should be removed in time to facilitate the recovery of the bur clamping mechanism of the dental handpiece.

3 come on

Air pressure oil spray can is the most ideal lubrication tool, it can not only lubricate the dental handpiece, but also achieve the effect of cleaning the bearing and wind wheel.

(1) Before using the oil spray tank, remove the bur (the screw-type dental handpiece can be reversed by 1/4 turn), wrap the handpiece with paper, and insert the nozzle of the oil tank into the air inlet of the dental handpiece to ensure sufficient air pressure.

(2) The air pressure oil spray tank must be used vertically, and each spray is 2-3s.

(3) For 2-hole dental handpieces, the nozzle is aimed at the large hole for spraying; for 4-hole dental handpieces, the nozzle is sprayed for the second largest hole.

(4) If it is oil dripping method, drop 4 drops of oil into the large hole, and then use an air gun to blow air intermittently into the oil filling hole for 30 seconds.

(5) It is strictly forbidden to use industrial lubricating oil for lubrication to prevent patients from being poisoned.

(6) Dental handpieces that are not used for a long time should be filled with oil, sealed and stored.

Repair of dental handpiece 


 

Dental high-speed handpieces come in a wide variety. According to the up and down needle method of the bur, it can be divided into rotary handpiece, push-type handpiece, and push-type handpiece; according to the size of the handpiece, it can be divided into mini-type handpiece, standard handpiece, and torque-type handpiece; according to whether it is equipped with optical fiber It can be divided into handpieces with optical fiber and handpieces without optical fiber.

To overhaul a machine, you must first understand the basic principles and usage of the instrument. Without knowing how to use the instrument correctly, it is difficult to recognize the abnormal state of the instrument. In this case, it is very difficult, sometimes even impossible, to do a good job of overhauling the instrument. The same goes for servicing a dental handpiece, which should begin with a "ask," "see" and "check" approach.

Question: Refers to asking the user about the process of failure, such as whether the head of the dental handpiece does not come out of water, whether it is rotating, whether there is noise (rustling, howling), and whether it is shaking;

Look: just look at the appearance of the dental handpiece, if it has been bumped and dropped, there must be traces of the collision on the appearance;

Inspection: It is to install a standard rod or bur and turn it by hand, listen to the sound or feel whether there is any obvious abnormal phenomenon inside, and then carefully check and prescribe the right medicine, which is very important for developing correct maintenance ideas.

Maintenance is to find out the cause according to the fault phenomenon, eliminate the fault, provide technical support for the doctor, and treat the specific reason in detail.

 

Fault 1: Poor water supply occurs 

Including: (1) Insufficient water supply; (2) Uneven water volume; (3) Water supply is not foggy; (4) No water at all.

Check where the water is blocked:

( 1) Tubing: Remove the turbo dental handpiece and check if a proper amount of water flows out of the tubing. If no water comes out, there may be a problem with the plumbing or the unit's water supply system (poor connection or malfunction, and insufficient water pressure at the water source)

( 2) Interface: Connect the interface with wires for trial operation. If the proper amount of water does not flow out, it indicates a problem at the connection (limescale, etc. clogs the water supply system or the connection is loose, causing insufficient pressure).

(3) Dental handpiece body: After removing the shaft core from the turbine, install the interface for operation. If the proper amount of water is not coming out, then there is a problem within the turbo handpiece body (dirt in the water supply hole or blockage of the water supply in the turbo handpiece).

(4) Shaft core: If the water supply in the above 3 items flows out normally, it is the problem of the shaft core (the water supply nozzle is blocked).

Fault 2: The nozzle of the shaft core is blocked 

Solution:

( 1) Remove the end cover and take out the shaft core.

(2) Remove the nozzle cleaning needle behind the brush, and insert the needle straight into the nozzle.

(3) The nozzle cleaning needle should be inserted to the upper groove (the needle passes through the air injection groove). Use a special brush to clean this part of the dust.

(4) Blow off with a three-purpose gun, etc. from the bur side.

(5) When installing the shaft core on the dental handpiece head, be sure to install the O-ring seal correctly.

Fault 3: The bur is easy to fall off, the bur cannot be pulled out, and the axis vibrates 

Solution:

(1) When selecting a bur, you must confirm the allowable speed range specified by the bur manufacturer, otherwise the bur will easily fall off when the cutting load is greater than the clamping force of the chuck.

(2) The short-handle bur should be used for the mini dental handpiece head, and the long-handle bur is easy to fall off when it is installed.

(3) Do not use worn and thinned burs, bent burs, or burs with missing edges, otherwise the durability of the bearing will be affected.

(4) After the bur is installed, the bur must be pulled out to confirm that it is firmly installed. If it is not inserted deep, or too shallow, it will cause the danger of the bur flying out.

Fault four: The dental handpiece does not turn or the speed is slow

Solution: 

(1) The head of the dental handpiece collides, falls and deforms, which hinders the operation of the wind wheel. As long as it is restored with the right tool, the wind wheel can be made to operate flexibly.

(2) Bearing lacks oil lubrication. Lubricate with dental handpiece lubricant.

(3) The bearing is damaged. Just replace the bearing with the same type.

(4) Low air pressure. If it cannot reach 2. 0 - 2. 5kgf /cm2, adjust the air pressure to stabilize the air pressure at 2. 0 - 2. 5kgf /cm2, and the speed will be normal

 

Maintenance Note:

It is forbidden to use burs with non-standard handles

Do not use bent or deformed burs

Do not press the cover until the dental handpiece is completely stopped

It is forbidden to immerse the dry heat disinfection box in chemical solution for disinfection, and it is recommended to use high temperature and high pressure steam for disinfection

Do not use dental handpieces without disinfection

Unsterilized dental handpieces are prohibited from being sent for repair

 

Good habits to prolong the life of dental handpieces:

1. The sand produced by the sandblasting machine without "anti-suckback" is very harmful to the bearing of the dental handpiece, so try not to use it in the same connecting pipe

2. Ultrasonic cleaners can cause great damage to bearings, so do not use ultrasonic waves to clean dental handpieces

3. The clamping system of the dental handpiece is not durable, or the bur cannot be clamped. Check whether the handle does not meet the standard bur, or the use of inferior burs has damaged the movement of the dental handpiece.

4. Do not increase the pressure by yourself because the drill is not moving. In most cases, the bur is worn out. It is recommended to replace the bur

5. The compressor needs to be cleaned, filtered and waterproofed frequently, otherwise the water in the air will damage the bearing.