FPI ch4 Dental Mirror

What is a dental mirror used to view?

Tooth surfaces and intraoral structures that cannot be seen using direct vision.

Name the three common types of dental mirror surfaces.

Front surface, concave, and plane (flat surface).

What is a key characteristic of a front surface mirror?

It produces a clear image with no distortion but the reflecting surface is easily scratched.

What does a concave mirror produce, and what is its drawback?

It produces a magnified image, but the magnification distorts the image.

What does a plane (flat surface) mirror produce, and why can this be a problem?

It produces a double image (ghost image), which can be distracting.

Where should the mirror head never be positioned, and why?

Against the buccal mucosa or tongue, because this hides the reflecting surface from view.

What are the four functions of the dental mirror?

Indirect vision, retraction, indirect illumination, and transillumination.

Define indirect vision.

The use of a dental mirror to view a tooth surface or intraoral structure that cannot be seen directly.

Define retraction as it relates to the mirror.

Using the mirror head to hold the patient's cheek, lip, or tongue so the clinician can view tooth surfaces otherwise hidden by soft tissue.

What is typically used to retract the lip instead of the mirror, and why?

The index finger of the nondominant hand, because it is more comfortable for the patient.

Define indirect illumination.

The use of the mirror surface to reflect light onto a tooth surface in a dark area of the mouth.

Define transillumination and explain what the term literally means.

Transillumination is the technique of directing light off the mirror surface and through the anterior teeth; "trans" means through and "illumination" means lighting up.

Why is transillumination only effective on anterior teeth?

Because anterior teeth are thin enough to allow light to pass through them.

What does a carious lesion or restoration look like when a tooth is transilluminated?

It appears as a shadow (a change in translucency).

What is a fulcrum?

A stabilization point that provides support for the clinician's hand during periodontal instrumentation.

Which hand holds the dental mirror, and why?

The nondominant hand, so the dominant hand is free to use the periodontal instrument.

Distinguish between an extraoral fulcrum and an intraoral fulcrum.

An extraoral fulcrum is a stabilization point outside the mouth (usually the chin or cheek); an intraoral fulcrum is a stabilization point on a tooth surface inside the mouth.

Is an intraoral fulcrum required when using only a dental mirror?

No, it is optional with a mirror but recommended when using a periodontal instrument.

According to the chapter, what is the most important sense during periodontal instrumentation, and why?

The sense of touch, because it allows efficient detection of subgingival calculus and reduces unnecessary strokes.

What happens to clinicians who do not develop a refined ability to feel calculus?

They must remove calculus "by default," making many unnecessary strokes, which places stress on the hands and can lead to musculoskeletal injury.

What muscle group has been specifically linked to neck and shoulder injury from poor posture during instrumentation?

The trapezius muscle (static postures of the trapezius).

Why is determination to use direct vision considered an ergonomic risk?

Because achieving direct vision instead of using the mirror causes unnatural postures and muscle contractions that can lead to injury.

What benefit has been shown for dental professionals who routinely use a mouth mirror for indirect vision?

Fewer headaches and reduced neck/shoulder discomfort.

Should mirror use be taught first on the maxillary arch or the mandibular arch, and why?

The maxillary arch first, because teaching it first on the mandibular arch causes students to "cheat" using direct vision and fail to master indirect vision.

What happens to students who "cheat" by using direct vision on the mandibular arch?

They continue to depend on direct vision when they move to the maxillary arch, resulting in early acquisition of poor postural habits.

What should NOT be used to retract the cheek, and why?

The instrument shank, because retracting with it is uncomfortable for the patient.

What is the recommended "Frisbee-style" positioning when first placing the mirror between the arches?

The mirror head is placed between the dental arches with the reflecting surface parallel to the maxillary occlusal surfaces.

Name two techniques to stop fogging of the mirror's reflecting surface.

Warm the reflecting surface against the patient's buccal mucosa, and/or ask the patient to breathe through the nose (also: wipe with a defogging solution or gauze moistened with mouthwash).

During transillumination, where should the clinician be looking—at the teeth or at the mirror?

Directly at the teeth, not at the mirror's reflecting surface.

What patient head position should be requested during use of the dental mirror?

The patient should position their head straight, toward, or away from the clinician, as appropriate for the sextant being viewed.