In dentistry, rotary instruments are essential as they are the only way to perform most types of procedures. They can be equipped with different tools, such as burs and polishing cups to perform multiple procedures aimed at improving the patient's oral health.
Nowadays, dentists can rely on two different types of rotary instruments: the dental turbine, also known as the high-speed handpiece, and the micromotor.
Furthermore, the micromotor can be equipped with a handpiece lempeng and a contra-angle handpiece. The latter is widely used as it can remove caries in a more controlled way.
Due to its characteristics and functions, the contra-angle handpiece has become a vital element of any dental practice. Moreover, it is the only tool that allows the dentist to polish restorations. Therefore, high-quality contra-angle can play a major role in the quality of dental restorations.
A contra-angle handpiece is a special device that the dentist can connect to a micromotor. Their main function is to remove caries and perform polishings.
These devices operate at a slow speed but offer good and constant torque. Therefore, turning them into the ideal option to work on semi-hard dental tissues.
These special tools are designed with an angle similar to the one of a high-speed handpiece. This allows the dentist to use it comfortably inside the mouth. The angle it possesses helps the dentist place the burs at an adequate position in regard to the tooth that is going to undergo treatment.
It is essential to understand that the contra-angle handpiece can only function if it is connected to a dental micromotor. Nonetheless, it doesn't matter if the micromotor is pneumatic or electric.
The contra-angle handpiece is mainly used to remove caries near the pulp chamber and perform polishings. This polishing is usually done to the patient's teeth during a prophylaxis appointment. However, it is also widely used to polish a dental restoration after it is finished to make it feel smooth and look shiny.
Although the contra-angle handpiece is already reliable, the selector wheel at bottom of the micromotor can regulate the torque and speed of the contra-angle.
Unfortunately, the lack of an irrigation system in most contra-angle and micromotor models is a big downside for dental treatments.
Although the contra-angle handpiece operates at low speed, it is still fast enough to produce and release heat. This frictional heat can cause discomfort, pain, and even pulp damage.
To prevent this issue, dentists are advised to avoid activating and pressing the blur or polishing cup against the tooth for long periods. Instead, it should be used intermittently to avoid overheating the tooth and causing any discomfort.
To use the contra-angle handpiece, the dentist just needs to plug it in on the upper end of the motor mikro dental. Afterward, pressing the pedal is enough to activate the rotor inside and cause the bur or polishing element to spin.
Most micromotors are air-driven, meaning that they work thanks to pressurized air. When the dentist steps on the pedal, air travels through the hoses into the handpiece. The air activates the rotary mechanism which in turn activates the contra-angle handpiece.
It is worth noticing that the burs used on the high-speed handpiece are smaller and can't fit inside the contra-angle. Therefore, there are special burs designed for this device. Nonetheless, there are special adapters that can be used with a regular bur. This allows the dentist to use it on the contra-angle handpiece without any issues.
The contra-angle handpiece is mainly used to remove caries on semi-hard teeth tissues.
The dentine is a tissue softer than enamel. Therefore, it is easier to cut and wear down. This can make it difficult for the dentist to avoid removing excess tissue by accident. However, the low speed at which the contra-angle handpiece operates helps the dentist have more control.
This allows the dentist to remove the decayed tissues and prep the tooth in a safer way. It also lowers the risk of performing accidental pulp exposure while eliminating a caries lesion near the tooth's pulp chamber.
The contra-angle handpiece is also commonly used to perform polishing procedures. This handpiece can be equipped with different types of polishing cups, brushes, discs, and mops. This allows the dentist to polish both the teeth and the restorations.
The polishing cups and brushes are normally used during prophylaxis appointments. The dentist or the hygienist applies a special prophylaxis paste on the teeth and then proceeds to slowly polish each tooth. This leaves them smooth and shiny while also reducing the risk of developing plaque build-ups.
On the contrary, polishing discs are used to polish restorations after the dentist finishes bonding them. These discs come in different sizes and colors. Moreover, the disc's color indicated how abrasive it is. It is recommended to begin polishing with a strong disc to remove any uneven imperfections and then move down the scale to a less abrasive one. This smoothes the restoration's surface.
Lastly, the contra-angle handpiece can be equipped with polishing mops. This allows both dentists and laboratory technicians to polish acrylic restorations, such as provisional dental crowns and dentures. This creates a smooth texture that makes the prosthetic restoration look more natural. Moreover, it helps it blend with the other teeth or the mouth in the case of a fully edentulous patient.
The contra-angle handpiece offers versatility and safety while working near the dental pulp chamber. However, its slow speed makes it less optimal to work on the enamel.
On the other hand, the high-speed handpiece can cut enamel without any issues. However, its speed also increases the risk of accidental damage while working on the dentine.
For this reason, it is highly advised to use both tools while performing a restoration. Preparing the enamel with the high-speed handpiece and then switching to the contra-angle after reaching the dentine can improve the results and safety of the treatment.