Dentsply Sirona's Operating Instructions for the Midwest E Pro and E Plus attachments run to more than fifty pages, and a striking share of that content is devoted to exactly one topic: how to condition the instrument between patients. That is not padding. It is the manufacturer telling you, in detail, precisely what protects a fifty-nine-gram motor and its attachments through years of daily sterilization cycles.

Never clean in an ultrasound bath. Never immerse in disinfectant solution. Two sentences, printed in bold in the manufacturer's own manual.

30 sec

Purge time for water and air channels before each patient

1 hr

maximum time before conditioning after treatment

<38°C

maximum water temperature for manual brushing

135°C

standard steam sterilization temperature

Before Each Patient: The 30-Second Habit That Prevents Overheating

Purge the water and air channels for 30 seconds.
Insert the instrument onto the motor (motor at standstill).
Insert the bur instrument.
Set a sufficient amount of cooling water, more than 50 mL/min.
Use filtered water only, below 50 microns.
Check the nozzles for blockages or lime deposits, and clean if necessary.

After Each Treatment: The Eight-Step Follow-Up Sequence

Purge water and air channels for 30 seconds, directly at the treatment center.
Remove the bur instrument with tweezers.
Pre-disinfect directly at the treatment center: spray the surface with disinfectant, then wipe it off with a cloth. In the US and Canada, the manual names CaviCide and CaviWipes specifically as approved agents.
Detach the instrument from the motor.
Transport it to the hygiene room in a suitable transport container.
Condition it, preferably with automated cleaning and disinfection equipment; manual conditioning is described as possible only in exceptional cases where national or local regulations allow it.
Apply spray to the instrument (Midwest Plus Aerosol Spray only).
Sterilize the instrument and its accessories.

Automated Conditioning: The Manufacturer's Preferred Route

Dentsply Sirona's instructions treat automated cleaning and disinfection as the default, with manual cleaning positioned as an exception. If your practice uses a washer-disinfector, it must be approved by its own manufacturer for dental instruments and comply with EN ISO 15883-1, for example, a 95°C cycle held for 10 minutes.

Check cleanliness after conditioning, under good lighting (minimum 500 lux) with a color rendering index of at least 80 Ra.
Repeat the cycle if the instrument is still dirty.
Blow out the instrument at a maximum of 3 bar.
Perform manual care of mechanical parts and the push-button chuck (see below) even after automated conditioning.
Pack it in sterilization- and storage-suitable material, such as paper/plastic composite packaging.
Sterilize.

Manual Cleaning: Only for Exceptional Cases, and Only This Way

TWO RULES THE MANUAL STATES IN BOLD, TWICE

Never clean in an ultrasound bath.
Never immerse in disinfectant solution.

Manual conditioning is explicitly framed as an exception, permitted only if your national or local regulations allow it, and only when performed exactly as specified:

Brush the instrument under running water below 38°C (100°F), at least drinking-water quality, for at least 10 seconds, until no dirt is visible, under good lighting.
Flush the drive channels with spray.
Clean and disinfect spray channels with suitable agents and adapters per the manufacturer's instructions.
Blow out spray channels with adapters at 2.5–3 bar for at least 10 seconds, until no more moisture is displaced.
Conduct thermal disinfection or unwrapped steam sterilization.
Perform manual care of mechanical parts and the push-button chuck.
Pack and sterilize.

Use only a soft, clean, disinfected brush, and only disinfectants with proven bactericidal, fungicidal, and virucidal properties and no protein-fixing effect.

dental handpiece disassembly workbench on Repair Guru

Manual Maintenance: Mechanical Parts and the Push-Button Chuck

Mechanical parts: at least twice a day, every time

Dentsply Sirona specifies maintaining mechanical parts at least at noon and evening, prior to every sterilization, and after every thermal disinfection cycle that lacks integrated maintenance.

Fit the spray adapter onto the nozzle of the (disinfected) spray can.
Insert the instrument until it snaps into place and hold it.
Spray for 1–2 seconds, holding the can upright.
Wipe any spray that comes out with a disinfection cloth.
Repeat until the spray runs clear.

The push-button chuck: at least once a week

Care of the clamping system removes deposits and preserves proper function, per the manual, and is specified at a minimum weekly interval, using the same Midwest Plus Aerosol Spray, held upright, sprayed for 1–2 seconds directly into the chuck opening, with excess wiped off with a disinfection cloth.

Both of these steps use one product only: Midwest Plus Aerosol Spray. The manual repeats this instruction at every maintenance step, which is a strong signal that substituting another lubricant is not something the manufacturer has validated.

Sterilization: Temperatures, Times, and the Cool-Down Trap

Packaging	Holding time at 135°C (275°F)	Drying time
Wrapped instruments	10 minutes	30 minutes
Unpackaged instruments	3.5 minutes	0–1 minute

Sterilize using a steam sterilizer with saturated water vapor at 135°C (275°F) with an overpressure of 2.13 bar (30.89 psi). Gravity displacement steam sterilizers are permitted. Do not exceed 140°C (284°F), even during the drying phase.

After sterilizing: remove the instrument from the steam sterilizer immediately (it is hot; risk of burns), and never attempt to accelerate cooling by immersing it in cold water, which can damage the instrument. Store all instruments protected from contamination, and re-sterilize once the storage period has elapsed.

The Overnight Rule and Storage Between Uses

Never leave an instrument on the motor overnight to prevent oil from leaking into the electric motor.
Never lubricate the electric motor itself. Only the attachment gets the spray treatment described above.
Sterilize before initial startup, and after any longer break in use, clean and maintain the instrument before returning it to service.

Monthly and Annual Checks: The Ones Easy to Forget

MONTHLY

Test the FG clamping system with a chuck tester (22 N withdrawal force)
Check the expiry date on the chuck tester itself before using it
Log the date and result of each test

ANNUAL

Check the clamping system of contra-angle and straight handpiece burs
Review elastomer (O-ring) wear across your attachment fleet
Replace elastomers according to their degree of wear

A Daily, Weekly, and Monthly Rhythm You Can Print

☐ Purge water and air channels for 30 seconds before each patient

☐ Confirm cooling water exceeds 50 mL/min and is filtered below 50 microns

☐ Pre-disinfect at the treatment center immediately after each patient

☐ Run automated conditioning (or manual conditioning only if locally permitted)

☐ Apply Midwest Plus Aerosol Spray to mechanical parts at least twice daily

☐ Sterilize at 135°C per the wrapped/unpackaged holding times above

☐ Remove instruments from the sterilizer immediately after the cycle

☐ Detach every instrument from its motor at the end of the day

☐ Spray the push-button chuck weekly, and run the FG chuck test monthly

Related Readings from RepairGuru :

What Dental Teams Say About Following the Manual Closely

★★★★★

“We had been immersing attachments in disinfectant for years before someone actually read the manual. That single change alone seems to have extended the life of our chucks.”

— Dental Hygienist, group practice

★★★★★

“The chuck test takes about thirty seconds and gave us a genuinely objective way to decide when to service an attachment instead of guessing.”

— Practice Manager

★★★★★

“Printing the after-treatment sequence and posting it in the hygiene room ended a lot of 'did we spray that yet' conversations.”

— Sterilization Coordinator

Midwest E Maintenance FAQs: What Teams Ask Most

Can I clean a Midwest E attachment in an ultrasonic bath?

No. Dentsply Sirona's Operating Instructions state, in bold, never to clean in an ultrasonic bath and never to immerse the instrument in disinfectant solution.

How soon after treatment do I need to condition the instrument?

Immediately, or at the latest, one hour after treatment, per the manufacturer's instructions.

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Midwest E Handpiece Maintenance Guide | Repair.Dental