Low-Speed Handpiece · Indigo CP

1What & why

Slow is the whole point.

Coronal polishing runs on the low-speed (slow-speed) handpiece — the workhorse motor that also powers lab trimming and caries excavation. For polishing it turns at roughly a few thousand RPM at most, and control matters far more than power.

High-speed handpieces (the ~400,000 RPM drills used for cutting tooth structure) have no role in polishing — that's a classic wrong answer.

2The parts

Motor, angle, pedal.

The partIts job

⚙️MotorThe body of the low-speed handpiece; runs forward and reverse.

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Provides rotationspeed is controlled by the foot pedal (rheostat)

Straight attachmentThe long straight nose cone that accepts lab burs.

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Lab & extraoral worknot the polishing attachment

angled contra-angle handpiece attachment

Contra-angleAn angled attachment that holds burs for intraoral use.

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Angled accessthe prophy angle is its polishing cousin

reusable metal prophy angle with rubber cup

Prophy angleThe attachment (usually disposable) that holds the rubber cup or brush.

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Holds cup / brushsnaps or screws onto the handpiece — the polishing business end

RheostatThe foot pedal that controls handpiece speed.

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Your speed controlgentle, partial pressure — "a little goes a long way"

A low-speed handpiece assembly labelled end to end: the metal motor body, the attachment collar where it meets the plastic, the pink prophy angle, and the white rubber cup at the tip. Below, a foot pedal labelled as the rheostat. — **Four parts and a pedal.** The motor body drives the prophy angle, which carries the cup; the **rheostat** at your foot sets the speed, and a little travel goes a long way. Release it and let the cup stop before the handpiece comes out — a spinning cup on the way out spatters and can catch tissue.

3Make it stick

Feather the pedal, not the tooth.

Test-takers who’ve been through the practical say it plainly: press the rheostat gently — a little goes a long way. Speed you don’t need becomes frictional heat in the tooth. The handpiece should hum, not whine.

4Beat the exam

"Which handpiece for coronal polishing?"→the low-speed handpiece

"What controls handpiece speed?"→the rheostat (foot pedal)

"What attaches the cup to the handpiece?"→the prophy angle

"A whining, high-pitched handpiece means…"→too much speed — more heat, more abrasion

"Before withdrawing the handpiece from the mouth…"→release the rheostat and let the cup stop turning — a spinning cup on the way out spatters and can catch tissue

5Check yourself

The speed of the low-speed handpiece during polishing is controlled by the:

The rheostat. Your foot feathers the pedal to keep RPM low and steady — gentle partial pressure, never floored.

5Check yourself

Which handpiece and attachment combination is correct for coronal polishing?

Low-speed + prophy angle. The high-speed is for cutting tooth structure, and the straight attachment is for lab work outside the mouth.

Recap

The whole thing in 4 lines.

✓Polishing = low-speed handpiece + prophy angle.
✓The rheostat (foot pedal) controls speed — feather it gently.
✓Excess speed → frictional heat and extra abrasion.
✓High-speed handpieces and lab attachments are wrong answers for polishing.