Both in restorative dentistry and endodontics, dental burs are fundamental instruments used in several procedures such as cutting, grinding and removal of hard tissues and soft tissues. Over the years, they have gone through significant changes in their design, materials used and areas of application that have improved accuracy and efficiency during dental care. The blog will discuss different types, classifications, benefits, processes and factors -giving a broad overview of these necessary tools in modern-day dentistry.
Classification of Dental Burs
Dental burs can be classified based on their attachment to handpieces, composition, rotational motion, head length, application, and shape.
By Attachment to Handpiece
- Friction Grip Burs (FG Burs): Used with high-speed handpieces.
- FGSS: Short shank burs.
- FGOS: Operative surgical burs.
- Latch Type Burs (RA Burs): Used with low-speed contra-angle handpieces.
- Long Straight Shank (HP Burs): Primarily used by dental laboratories with low-speed handpieces.
By Composition
- Stainless Steel Burs
- Tungsten Carbide Burs
- Diamond Burs
- Ceramic Burs
- Gold Burs
By Shape
- Round Burs: Used for cavity preparation, endodontic treatment, and bone surgery.
- Pear-Shaped Burs (330 Burs): Ideal for cavity preparation and removing caries.
- Spiral Cool-Cut Burs: Designed with a left spiral groove for efficient cooling and fast grinding.
- Flat End Tapered Burs: Simplify crown and bridge preparation.
- Round End Tapered Burs: Multi-purpose burs for crown and bridge preparation.
- Football Burs (Egg-Shaped Burs): Used for preparation, finishing, and trimming.
- Torpedo Burs: Designed for cavity preparation.
- Inverted Cone Burs: Used for creating undercuts for restorations and root canals.
- Straight Fissure Burs: Useful for creating parallel lines and flat floors during cavity preparation.
- Tapered Fissure Burs: Ideal for various actions during crown removal.
Factors Affecting Cutting Effectiveness and Bur Efficiency
a. Cutting efficiency
The highest amount of tooth tissue that the instrument is able to remove effortlessly within the shortest period possible defines its cutting efficiency among rotating dental instruments. Among these factors that affect this efficiency is rake angle, clearance angle, blade angle, number of blades, runout, flute finishing, heat treatment, flute geometry, spiral angle load sensitivity and speed.
b. Rake Angle, Clearance Angle & Blade Angle
Clearance angle reduces friction between the bur’s edge and tooth; thereby preventing it from digging into the tooth structure, which plays a very important role. For instance, while a positive rake angle increases bur-cutting efficiency it also decreases blade angle (thus reducing bulkiness of the bur) leading to probable clogging due to larger chips produced by it.
c. Number of Blades and Their Distribution
A reduction in the number of blades causes fast clearance of chips but less efficient cutting.
d. Runout
In the clinics, the acceptable average runout is 0.023mm. As the runout increases, so does bur vibration leading to unnecessary tooth removal.
e. Finishing of Flutes
A rotating cutter cuts each flute into the bur blank while manufacturing burs. Six-times cut burs are more efficient compared to two-times cut ones, which are the least efficient.
f. Heat Treatment
Heat treatment preserves the cutting edges, thereby increasing the bur’s shelf life.
g. Design of the Flute Ends
- Revelation Design: Flutes join at two junctions adjacent to the diametric cutting edges and this causes highly effective direct cutting action.
- Star Cut Design: The flutes unite at a common point on the axis of rotation about which bur rotates equally during lateral cutting for both designs.
h. Spiral Angle
Lower spiral angles in burs indicate better efficiency at high speeds.
i. Influence of Load
This is because burs have a maximum load/force threshold beyond which their cutting efficiency decreases due to torque. At high speed, this load should range between 60-120gm, whereas low rotational speed should be reflected by a range between 1000-1500gm for such loads.
j. Speed Influence
Within operational limits, higher speeds increase the abrasiveness and efficiency of the tooth-cutting instrument.
What are the benefits of Using Dental Burs in Restorations?
- Efficient Decay Removal: Dental burs efficiently eradicate decays and destroy part of the teeth, leaving holes clean and ready for filling.
- Precise Shaping and Contouring: They enable the formation of the tooth to retain restorative, making it fit properly.
- Sealant Preparation: Making use of burs tooth surfaces are made ready for pit and fissure sealants which is a barrier against tooth decay.
- Bonding Surface Preparation: These prepare the surface and contour it for dental bonding that enables strong bonds with materials such as zirconia crowns.
- Restoration Modification: Defective restorations can be removed by burs, thereby facilitating repairs or other suitable replacements.
These benefits enhance the effectiveness and longevity of dental restorations, contributing to better oral health outcomes for patients.
What is the process of Indirect Restoration?
Indirect restorations, performed outside the patient’s mouth, involve creating custom-fitted restorations in a dental laboratory. Here’s how dental burs are utilized in this process:
- Tooth Preparation: Burs shape teeth for crowns or bridges by reducing the tooth structure to make space for the restoration.
- Cavity Preparation: The cavities are made for the inlays and onlays that fit in or cover the tooth’s surface to bring back its function.
- Veneer Preparation: The teeth are prepared with burs for veneers by shaping the front surfaces for bonding thin shells of material.
- Root Canal Access: Burs access and shape root canals during root canal treatment preparation.
- Implant Site Preparation: They prepare bone and surrounding tissues for dental implants.
- Tissue Adjustment: Burs adjust gum tissue and bone levels, exposing more tooth structure for proper restoration.
- Temporary Restoration Removal: The removal of temporary crowns or bridges is facilitated when they do so for permanent restorations.
Material vs. Shape of Dental Burs
When it comes to choosing dental burs for various dental procedures, it all boils down to the material and shape. There is a significant difference in hardness and wear resistance between carbide and diamond burs, which affects their cutting abilities and durability. Carbide burs offer excellent ways of shaping teeth, while different shapes of bur, such as round, pear or cross-cut tapered, are used for cavity preparation, contouring and finishing, providing accurate cutting profiles. The combination of shape and material guarantees flexibility, economy and optimum performance that suits each treatment.
Summary
Dental Burs are one of the necessary parts of any dental clinic’s equipment. It is quite difficult to select among the great variety available all around the market, ensuring high-quality products. Dental Avenue India Pvt Ltd is a specialized company that facilitates access to these devices for medical practitioners. All items available here must be well examined before they get authorized by relevant international bodies that follow certain strict rules. If you want nothing less than the most appropriate dental burs, then Dental Avenue India Pvt Ltd can help you out.
