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The Guide to Dental Vacuum Pumps: Wet vs Dry

Aug 20, 2021 | Product News

wet vs dry vacuum

Your dental vacuum is a critical component of your dental practice, supporting the equipment that helps remove saliva, debris and bacteria from the patient’s oral cavity while you work. That translates to a safer experience for you and your staff, and a more comfortable one for your patients. Whether you’re outfitting your practice for the first time, or replacing older, outdated or broken equipment, before making the investment in a dental vacuum, you’ll want to familiarize yourself with the different options on the market and evaluate how each might best fit your needs.

At DENTALEZ, we’ve been providing dental vacuums to dentists for over 40 years. We understand the considerations our dentists face when making a decision of this magnitude, and we’re here to help clarify the different attributes of both wet and dry dental vacuums, so you can make the best decision for your practice. You’ll want to take a variety of factors into account, including: the amount of power you need, size of your space, noise considerations, the type of drainage options you have, the different ongoing maintenance needs and investments each type requires, and of course, cost.

Understanding Dental Vacuum Power

It’s critical to know how much power you’ll need in order to choose the right vacuum. That depends on the types of procedures you’ll be doing, and how many operatories and team members the vacuum has to support. You need to account for the number of high-volume evacuators (HVE’s), or how much vacuum power you need.

How many users a vacuum can serve is defined in “users”. So what comprises a “user”? It’s how many HVE’s and saliva ejectors (SE’s) will pull from that pump. The formula is fairly simple, and based on the number of users, though different depending on whether you’re using a wet or dry vac. It’s worth noting that a wet vacuums’ power gets diffused more quickly as you open up more lines.

A user can be defined as follows:
● for a dry vacuum: 1 user = 1 HVE or 5 SE’s
● for a wet vacuum: 1 user = 1 HVE or 2 SE’s

There are some efficiencies considering everyone isn't using the vacuum at the exact same time, but that can be offset by other efforts, especially if your practice added or plans to add additional suction devices for aerosol capture due to COVID, which also pulls from the vacuum pump.

Generalized estimates across typical practices see approximately 7-12 Hg of vacuum pressure needed for a general dental practice, while specialty practices may require up to 15-18 Hg.

Types of Dental Vacuum Pumps

The source of the vacuum pressure, or, how contaminants are evacuated, falls into one of these two categories. Wet dental vacuums (also referred to as wet-ring vacuum pumps) use water to create vacuum. Dry dental vacuums create that vacuum pressure by pumping dry air, using turbines or rotary vanes to create suction power.

Wet vacuum pumps were first used in dental practices in 1957. The technology hasn’t changed tremendously since then; they were and remain strong sources of vacuum power, despite their relatively compact footprint. As an investment, they cost less off the shelf than dry vacs, although the associated ‘penalties’ in water and electricity usage, not to mention maintenance, chip away at that initial economy fairly quickly (we’ll get into all the pros and cons a little further down). As a general rule, they do provide more vacuum power than their dry competitors, so they tend to be preferred in practices that perform more surgery or support a larger number of operators.

Dry vacuum pumps first became commercially available in the 1980’s, in response to the desire to consume less water. They tend to be larger but quieter, with consistently strong vacuum, require less maintenance and last longer than their wet pump predecessors.

Wet Dental Vacuums

How Wet Vacuums Systems Work

As noted earlier, wet or wet-ring vacuum pumps use a steady supply of water to create the pressure that provides the vacuum power of your pump. That water consumption is the Achilles’ Heel of the wet vac; a single pump wet vac uses ½ to 1 gallon per minute of use per day, while a dual pump (double ring) system - can consume 1-2 gallons of fresh water, per minute, each day. Because they’re powered by an electric motor that runs continuously at full speed, a steady stream of water runs through the pump the entire time the machine is on. That quickly adds up - often to an average of 360 gallons of water per day, which in turn drives up monthly sewer and electric bills, sometimes to the tune of thousands of dollars - on top of the environmental impact of such constant water waste.

So why choose a wet vacuum?

Several situations can drive that decision. First, the need for power. For some specialties and practices, there really is no dry vac that can meet the need for the vacuum power provided by a wet vac.

Second is location. In many buildings, especially multi-floor or older buildings, the ability to vent into existing piping can sometimes be the only logical option. For example if a practice is on the fifth floor of a multi-floor building in New York City, there may not be an existing exhaust pipe (nor the option to poke a hole) leading outside the building, option to penetrate the building exterior to accommodate an exhaust pipe, so working with the existing plumbing is the better solution.

And of course, cost is always a consideration. Dentists outfitting an entire practice for the first time or backfilling an existing space that fits a wet vac, or who are more comfortable paying the costs over time vs. in one initial investment, may find that the price tag of the wet vac fits their budget better. To help mitigate the volume and costs associated with excess wastewater, some wet vacs have a recirculator system which can be added to recycle and reuse some of the waste liquid before being released to the sewer.

Wet Vacs: Advantages and Disadvantages

As with anything, defining something as advantageous or not often depends on the circumstances it’s being applied to, combined with the priorities of the user.

Size: Wet vacuums traditionally have been more compact, requiring a smaller footprint, which can be important in offices without a lot of extra inches, or that lack a room that can be dedicated wholly to utility equipment.
Power: The amount of power you need is specific to your practice. Both wet and dry vacuums have a range of sizes, and powers of suction. Power is measured in inches of mercury (Hg). You will want to determine how much power you need, and work with your dealer to determine which machine makes the most sense for you.
Noise: Wet vacs until recently had been quieter, which of course translates to a quieter office and more flexibility in where you can place the machine. But recent changes in dry vac technology have reduced the difference and for some lines, dry vacs are quieter.
Longevity: Wet vacs have a lifespan range of 5-12 years, depending on the water quality and hours run.
Maintenance: Both wet and dry systems require daily flushing of the suction lines to remove blood and debris, and an approved disinfectant should be run through the tubing. However, there is additional trap cleaning required with wet vacs (a traditionally unpopular job). Because water contains minerals and pollutants that accumulate, the pump components wear more quickly, and the harsh cleaning solutions that are run through the machine daily also take a toll.
Cost: The initial investment for a wet vac is consistently lower than for a dry system. However, once the ongoing costs of water, electricity, maintenance, additional components and the shorter lifespan are considered, the dry vac is almost always the more economical choice, over time.

Dry Dental Vacuums

How Dry Vacuum Systems Work

In response to the desire to get away from the waste of water, the first dry vac systems by Ramvac were created in the early 1970’s. The first ones started out small for basic general dentistry. Instead of a steady stream of water constantly disposing of waste materials via the sewer pipes, dry vac design incorporates a collection tank to collect the liquids and solids from the chairs while the vacuum is running, and then at the end of the day, the tank (the size of which depends on size of clinic), gravity drains waste liquids into the sewer quickly, virtually eliminating unnecessary water waste.

Most dry vacs are belt driven which consume less electricity so over a year’s time electric usage is minimized, conserving costs and resources a couple of different ways. The up-front investment is higher, but quickly pays itself back -- often within 3-4 years.

For a vacuum that truly stands out for longevity, look for one that is oil-lubricated, like the Ramvac vacuums with Aeras Intel. Oil not only lubricates components, extending their life, it also makes for a stronger vacuum with stronger positive displacement. Maintenance is minimal; a routine annual filter and oil change to remove any pollutants that may have been pulled into the pump is standard.

Dry vacs work best for general dentistry practices and with (-7) to (-10) inches of vacuum, which means they can support a robust practice with multiple chairs and operators. Remember that a dry vac also requires a dedicated exhaust pipe/line to the outside.

Dry Vacs: Advantages and Disadvantages

Size & Volume: Dry vacuums traditionally have been larger, and louder than wet vac options. Newer models have significantly cut down their footprint and can run at a volume no higher than a handheld.
Power: Power: The amount of power you need is specific to your practice. Both wet and dry vacuums have a range of sizes, and powers of suction. Power is measured in inches of mercury (Hg). You will want to determine how much power you need, and work with your dealer to determine which machine makes the most sense for you.
Longevity: Dry vacs have longevity on their side, with many lasting up to 25 years with regular maintenance.
Maintenance: Both types require daily flushing of lines, and the gravity release of the solids from the collecting tank. Other than that, maintenance is minimal - an annual oil and filter change will keep a dry dental vacuum running efficiently for decades.
Cost: The up-front cost of a new dry vac will come with a higher price tag than a wet vac. But the investment breaks even within a few years, due to the absence of ongoing aggregate costs from water and electricity use associated with wet vacuums.

The Future of Dental Vacuum Systems

One of the new features of modern vacuums is the addition of smart technology. The Ramvac vacuum with Aeras Intel is one example, where embedded sensors in critical areas on the vacuum monitor for indicators that typically herald trouble, including overheating or unwanted moisture. The system forewarns staff and service teams, allowing for targeted diagnosis and service all of which can be done remotely, improving service outcomes and eliminating unproductive visits to the office. This ability to anticipate and avoid down-time is just one of the many ways DENTALEZ is making our dentists future-ready.

The purchase of the right dental vacuum for your practice can be done with confidence, with the right assessment of your needs and, like all big investments, careful weighing of the pros and cons of each model. For more information about the wet and dry vac options at DENTALEZ, visit

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