Types of Casters for Dental Equipment: Function, Mounting, and Material Explained

1- Types Of Casters By Function

Caster wheels are categorized into swivel casters for flexibility and movement freedom, fixed casters for stability, and dual-wheel casters for durability and strength. Each one of these casters serves a purpose depending on the need and features as follows:

Swivel Casters

Swivel casters can rotate 360 degrees around a vertical axis, facilitating the maneuverability and steering of the chair. These casters are best for tight spaces and frequent direction changes (e.g., dental stools and hospital beds).

The downside of these caster wheels is that they are less stable and can cause flutter, even in a straight-line movement, due to their unrestricted swivel mechanism.

Rigid (Fixed) Casters

Fixed caster wheels are excellent in directional control and are more stable than other casters. These rigid casters are ideal for practices where straight-line travel is needed, such as in dental instrument carts.

The drawback of these caster wheels is that they lack lateral movement, so they must be paired with swivel casters for turning.

Dual-Wheel Casters

Dual-wheel casters feature two wheels side-by-side in a single caster housing. They are perfect for heavy-duty applications that require a better weight distribution and smoother swiveling, such as dental compressor carts or heavy supply cabinets that need smooth movement across treatment areas.

The downside is that these caster wheels are slightly bulkier and may require more clearance due to their dual-wheel configuration.

2- Types Of Casters By Mounting Style

Casters are divided into strong and stable plate-mounted casters and stem-mounted casters, which are easier to use and save more space, enhancing workflow.

Plate-Mounted Casters

Flat-mounted caster wheels use a flat metal plate with four bolt holes to secure the caster to the base of the equipment, offering a wide surface area for attachment and ensuring a strong, stable connection.

These casters are commonly used in heavy-duty dental stools and sterilization units to enhance mobility and stability.

Plate-mounter casters require a flat surface for installation, and their bolted installation makes them hard to replace or reposition.

Stem-Mounted Casters

Stem casters attach through a single stem (threaded, grip ring, or expanding) that inserts into a tube or a socket. They are easy to install, remove, or replace because their single-stem design allows them to slide or screw directly into pre-fitted sockets without requiring tools or surface modifications.

These stem casters are ideal for dental stools and operator chairs because of their sleek and space-saving design and tool-free installation. But they have a low load capacity and may loosen with frequent movement or over time.

3- Types Of Casters By Material

Caster wheels can be classified according to the materials they are made from, such as shock-absorbent rubber, economical plastic, strong polyurethane, and durable brutal metal, each providing unique features.

Rubber Casters

Rubber caster wheels are soft, quiet, roll smoothly, and protect the floor, offering excellent shock absorption and grip. They are best for dental carts and mobile cabinetry on tile floors as they absorb minor vibrations.

The problem with these casters is that they wear fast compared to other kinds, and they are not suitable for oily or chemical-prone environments.

Nylon/Plastic Casters

Plastic wheels are lightweight and cost-effective, offering economical mobility for light-duty practices. They are also moisture-resistant and have low rolling resistance, which makes them perfect for lightweight dental stools and auxiliary equipment.

Unfortunately, nylon caster wheels are noisy on hard floors because their rigid material lacks shock absorption, producing clattering sounds during movement, and can scratch delicate surfaces due to their hardness and minimal grip.

Polyurethane Casters

Polyurethane wheels combine the resilience of rubber with the strength of plastic. They have a high load capacity, are resistant to chemicals, and have quiet movement thanks to their shock-absorbing tread.

These casters are durable and suitable for both hard and soft floors, making them ideal for mixed-surface environments and mobile X-ray units. Yet they are considered expensive, and can be too rigid for uneven surfaces.

Steel/Metal Casters

Metal caster wheels are built for strength and durability, capable of handling extreme loads, heat, and impact, with minimal rolling resistance. They are ideal for autoclaves or heavy-duty storage units.

The downside of these steel casters is that they are noisy and harsh on floors, so they require floor protection to avoid damaging it.

How To Choose The Right Caster

Choosing the right caster isn’t about finding the “best” one—it’s about selecting the right fit for your specific application. Casters vary widely in design and function, and their effectiveness depends entirely on the environment and demands of use.

To make an informed decision, consider the following key factors:

• Load Weight: Make sure the caster’s weight capacity exceeds the equipment’s total weight.
• Floor Surface: Consider what kind of floor the casters will roll on (tile, laminate, carpet, or mixed surfaces).
• Mobility Needs: Evaluate your need for mobility to decide between swivel casters for maneuverability or rigid ones for directional control.

Here are some tips for avoiding standard caster wheel selection mistakes

• Using rugged caster wheels, like those made from nylon, polypropylene, or metal, on delicate floors (such as hardwood, vinyl, or polished tile) can cause damage, including scratching or denting the floor. In dental clinics, where aesthetics and hygiene are required, rugged caster wheels can lead to visible wear and surface damage if used on delicate floors.
• Overlooking the weight limits of the casters can have devastating effects, leading to equipment failure and increasing the risk of workspace injuries.
• Ignoring environmental exposure, such as high temperatures, moisture, or chemicals (disinfectants, cleaning acids, or sterilizing agents) can degrade caster materials, causing corrosion, deformation, or premature failure.