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February 27, 2015
Nitrous Oxide (N2O) can be a valuable addition to the dental office analgesia armamentarium. Having a patient that is relaxed can lead to more successful outcomes.
N2O is delivered to the patient via a nosepiece or “hood.” Various equipment manufacturers have their own designs of hoods that are designed to be used either with or without a “scavenger system” (#71-30 or #71-301).
A scavenger system is designed to evacuate exhaled gases to minimize contamination of the ambient air within the operatory. The scavenger is connected to your vacuum system (via the HVE) to pull the gas away and vent it to the outside atmosphere (along with your main central vacuum vent).
To prevent the vacuum from pulling all of the gas before the patient can aspirate (and receive the benefits), all scavenging systems have a vacuum valve and gauge incorporated into the system. This valve controls the level of vacuum so the excess gas can be safely evacuated while the patient still receives an appropriate dose of N2O.
The gauge pictured below is typical of such devices. It has inlet and outlet connectors for the vacuum line, a control valve to adjust the flow, and a gauge to indicate the current flow setting. Note the green “safe” area indicated on the face of the gauge. Most systems incorporate clear labeling like this to make it easy to set the gauge correctly.
As the scavenger connects to a HVE valve, there is typically a 7/16” o.d. fitting at the end of the scavenger circuit. All HVE’s sold in the US are designed to take a standard 7/16” tip. This is also the size of the various aspirator tips on the market. These are standardized sizes.
The hood, however, will vary considerably from manufacturer to manufacturer. Most hoods will have two “inlet” connections for gas to flow to the patient’s nose from the flowmeter. If using a scavenger, there will also be one or more “outlet” hoses pulling the excess (and exhaled) gas away from the patient (and operatory). As an additional means of limiting flow (in addition to the vacuum valve and gauge already discussed) these “outlet” hoses are typically smaller in diameter than the “inlet” hoses. As these hoses fit over connectors, they are measured by inside diameter (i.d.). Whenever you need to replace one of these hoses, always measure the inside diameter to be sure of the proper size. Unlike HVE tips, there can be some variance here so it’s important to know what you have.
The Accutron scavenger circuit and hood has four connections. This system is also used on Belmed nitrous units. It uses two inlet hoses of 3/8” i.d. (these hoses connect to the side of the hood) and two outlet hoses of ¼” i.d. (these hoses connect to the scavenger “hub” that snaps onto the front of the hood).
The use of nitrous oxide in your practice can be an important tool in offering your patients a relaxing experience, enhancing recall rates, and resulting in more successful procedures. The scavenging circuit plays an important role in your anesthetic system, allowing you to safely deliver a controlled flow of nitrous oxide and oxygen to your patient, while keeping staff protected.
Nitrous systems aren't a necessary component of your dental practice, but they can be beneficial. The use of nitrous oxide in your practice can be an important tool in offering your patients a relaxing experience. A relaxed patient will result in more successful procedures enhancing recall rates. The scavenging circuit plays a crucial role in the use of nitrous oxide, allowing you to safely deliver a controlled flow of nitrous oxide and oxygen to your patient while keeping staff protected.
June 29, 2014
The turbine is the heart of the high-speed handpiece and bearings are the heart of the turbine.
Bearings are the most common failure point of a turbine and are often the primary differentiator between one turbine and another.
Way back in Practice Tips #22, “High-speed Handpiece Design,” we covered all of the components that make up a complete bearing assembly. For ease of reference, we’ve included the diagram of a bearing assembly below. For further explanation of the components, check out Practice Tips #22.
Today, we’re going to look at some of the different bearing materials and designs on the market.
Many turbines use stainless steel bearings that require lubrication. The balls, inner ring, outer ring, and shield are all made of stainless steel. The ball cage will be made of a polymer (there are a few more variations within this broad category and different types of polymers for the cage, but all these permutations require lubrication).
Stainless steel bearings have been in use for decades and are a proven design with good performance and good reliability. They are manufactured in large quantities for dental turbines and many other industries so cost is comparatively low. As these turbines incorporate metal bearings in metal housings, they require lubrication. Most handpiece lubricants on the market are designed to withstand the rigors of sterilization, but these turbines should still be lubricated every time they are used (see our handpiece maintenance products here). Lubrication after using and before sterilization is generally adequate, but consult the manufacturer of your turbine and lubricant to determine if post sterilization lubrication is required as well.
Many turbines currently on the market are advertised as “lube free.” There are 2 primary methods of manufacturing lube free bearings:
LTL bearings are still the same basic stainless steel design so they share many of the features of standard stainless bearings. The greasing and sealing process adds to the cost (and they aren’t manufactured in quantities like the standard bearings), so they will add to the cost of the turbine or handpiece that uses them. The sealing process, also, prevents debris from getting into the center of the bearing assembly and on the actual steel balls, so maintenance is a little easier. Nonetheless, these bearings (or, more accurately, turbines that incorporate these bearings) still need to be cleaned after every use and before sterilization.
Last of all, there are ceramic bearings. Ceramic bearings are actually made of a ceramic silicon nitride, so they have a very smooth low-friction surface. The low-friction surface removes the need for lubrication and also minimized heat build-up during use. They, also, withstand high temperatures very well, so they withstand repeated sterilization better than stainless steel bearings.
Both LTL and ceramic bearings will run at higher rpm than stainless bearings and are better able to handle higher air pressure (they typically require in excess of 40 psi drive air pressure). The higher rpm can help these turbines cut faster so some practitioners feel they perform better (naturally, this is subjective).
In summary, the materials and techniques used to manufacture lube free bearings are more costly than standard stainless bearings, so these bearings (or the turbines that incorporate them) often cost twice as much as turbines that need to be lubricated. It’s up to the practitioner if the advantages are worth the expense.
April 30, 2014
Before we get started, we want to reiterate our number one objective with Practice Tips (and when you call us): to empower your practice with basic maintenance, installation, and repair knowledge, so that you're not paying full-service distributors exorbitant fees on a regular basis. While taking the time to familiarize yourself with your equipment will have a learning curve, you'll be glad you did. Once you get it down, you'll be saving lots of money and will feel more in control of your practice. Without further adieu: