Electrical Equipment and Advanced Esthetic Modalities
Modality questions test what the current does, its indications, and its absolute contraindications. Expect the difference between direct and alternating current, the purpose of each device, and safety checks before you plug anything in.
Core devices
- Galvanic (direct current): desincrustation (negative pole, alkaline, softens sebum) and iontophoresis (positive pole, drives water-soluble products in).
- High frequency (alternating, Tesla): violet-ray electrodes; used for a germicidal and drying effect and for vasoconstriction after extractions.
- Microcurrent: very low amperage; used for tone and circulation; no muscle contraction.
- Ultrasound: high-frequency sound waves; typically around 1 MHz for facial work; requires conductive gel and continuous motion.
- LED: blue around 415 nm for acne bacteria, red around 633 nm for healing and collagen support.
- Steamer and hot towels: soften tissue before extraction; use distilled water and keep the steam at a comfortable distance.
Safety
Inspect cords and plugs, keep equipment away from water, dry your hands, and explain the sensation before starting. Ask about pacemakers, implanted defibrillators, metal implants, pregnancy, epilepsy, photosensitizing medications, and broken skin.
Worked example
A client with a pacemaker requests high-frequency treatment after extractions. Reasoning: high frequency is alternating current delivered through the body, and implanted electronic devices are an absolute contraindication - the current can interfere with pacing. Correct answer: skip the device, use a topical antibacterial and a cooling mask instead, and document.
Traps
Leaving an ultrasound head stationary, which concentrates energy. Using LED on a client taking a photosensitizing drug. Treating high frequency as "sterilization." And assuming a device is safe because it is noninvasive.