Your bulletproof ortho practice needs to be foolproof first – that’s Poka-Yoke

Techniques for standardization of work and prevention of errors and defects have been deeply rooted in the principles of lean management. One of the most cardinal aspects of the lean manufacturing system is Poka-Yoke. Coined in Japan during the 1960s by Shigeo Shingo, an industrial engineer at Toyota, Poka-Yoke was formally termed “Baka-Yoke”, meaning “fool-proofing” but was dismissed due to its dishonorable and offensive connotation.

What is Poka-Yoke?

Poka-Yoka is an efficient technique that ensures that favorable conditions exist before a process step is executed. This helps prevent defects from occurring because defects waste time, money, resources, and patience. In the scope of LeanOrthodontics®, Poka-Yoke is a valuable accolade that is worth investing in.

A “soft Poka-Yoke” also occurs when a system identifies a fault and alerts the user, for example by means of an optical or acoustic signal (warning light, buzzer, vibration alarm).

Application of Poka-Yoke in orthodontics

Activating loose braces
During treatment, you can test patient compliance with the help of this compliance check:
Install screws to widen and shift the jaw into the appliance as they’re highly scalable. The patient turns the screw himself every week. When he returns after eight weeks, it should show eight turns. At the same time, the braces should fit perfectly if he has worn them accordingly.

If the patient has not worn the braces as instructed, you’ll be able to assess it by checking at the end of eight weeks. Here, you can get an idea of how long you will need to complete the treatment based on your patient’s cooperation.

In this case, you may notice two deviations – first, the patient wears but fails to adjust the braces in which case the turns of the screws are missing. Second, the patient adjusts the screws but fails to wear in which case, the braces begin to “tilt”.

Baxmann keys
The Baxmann Keys are as follows:

  • the cuspids always stand on both sides in class I.
  • the molars are always stably interlocked on both sides in a complete class I, II, or III.
  • the midlines of the upper and lower jaw are identical and parallel to each other and to the facial axis.

A deviation from upper jaw to lower jaw centerlines of a maximum of 2 mm to each other or to the facial axis is tolerable if the corresponding axes are parallel. In the case of asymmetry, the upper and lower jaw must also follow the curvature of the facial axis in parallel.

Another Poka-Yoke technique applicable in Lean Orthodontics® is the Baxmann Keys. Every employee can learn them and help to ensure that they are adhered to. They are not only used for the final check of the occlusion but more importantly for checking the anchorage. Loss of anchorage can be the number one source of error in the event of undesired side effects or deviations from the planned treatment result.

Maximum anchorage
If you need maximum anchorage, opt for a mini implant instead of dependent elastics. Mini implants are cheap, simple to use, and fairly usually. You don‘t want to place mini-implants? Then I‘ll show you a safe and reproducible way to use them. Or you look for a colleague who inserts them for you.

The value of Poka-Yoke is that it helps people work right the first time, making mistakes impossible to happen. With Poka-Yoke, you can identify causes and strategically avoid mistakes from commencing.

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