MODULE 4 - Study Notes on the Use of the Dental Mouth Mirror

Module 4: Use of the Dental Mouth Mirror

Introduction to Dental Mirror

  • A dental mirror is an essential tool in dentistry used to view tooth surfaces that are not accessible via direct vision.

  • For example, a clinician may need to examine the lingual surfaces of the maxillary anterior teeth using a dental mirror or mouth mirror.

Functions of the Dental Mirror

  • The dental mirror serves four key functions during periodontal instrumentation:

    • Indirect Vision: Allows viewing of surfaces that cannot be seen directly.

    • Retraction: Holds patient's soft tissues like cheek, lip, or tongue out of the way for better visibility.

    • Indirect Illumination: Reflects light onto tooth or soft tissue structures in dark areas of the mouth.

    • Transillumination: Directs light through anterior teeth to reveal issues like carious lesions.

Working-End of a Dental Mirror

  • The working-end of a dental mirror consists of a reflecting surface that is used to facilitate visibility.

Types of Dental Mirrors

  • There are three common types of dental mirrors:

    • Front Surface Mirror:

    • Reflecting surface is on the front of the glass.

    • Produces a clear mirror image with no distortion.

    • Most commonly used due to high image quality but can be easily scratched.

    • Concave Mirror:

    • Reflecting surface is on the front of the mirror lens.

    • Produces a magnified image but is not recommended as magnification can distort the image.

    • Plane (Flat Surface) Mirror:

    • Produces a double image, often referred to as a ghost image.

    • More durable due to the reflecting surface being on the back of the mirror lens.

    • Not recommended for clinical use due to the distracting nature of the double image.

Stabilization of the Dental Mirror

  • During instrumentation, the clinician uses the nondominant hand to grasp the mirror.

  • Stabilization techniques include:

    • Using the ring and index fingers to steady the mirror within the patient's mouth.

    • Resting fingers on the patient’s chin, cheek, or tooth surface for better control.

Fulcrums

  • Extraoral Fulcrum: A stabilization point located outside the patient's mouth.

  • Intraoral Fulcrum: A stabilization point for the hand resting on a tooth surface.

    • Using an intraoral fulcrum is optional with a dental mirror but is recommended especially when used alongside a periodontal instrument.

Detailed Functions of the Dental Mirror

Indirect Vision

  • This involves utilizing the mirror to view a tooth surface or inner structure not directly visible.

Is Direct Vision the Best?

  • For most clinicians, the visual sense is their dominant means of perception.

    • Touch: While visual skills are vital, touch is considered an invaluable asset for detecting and removing deposits.

  • Mastery of indirect vision is critical as it helps prevent uncomfortable positions when trying to see teeth directly.

Retraction

  • This function uses the mirror head to hold back soft tissues (cheek, lip, tongue) allowing for unobstructed views of tooth surfaces.

    • Retracting Tongue:

    • The mirror is often used to keep the tongue out of the clinician's view of the teeth.

Retraction of Lip

  • The index finger serves to retract the lip away from the teeth, which is generally more comfortable for the patient than using the mirror for this purpose.

Indirect Illumination

  • The mirror reflects light onto tooth surfaces or soft tissue structures located in the darker regions of the mouth.

Transillumination

  • Transillumination is a technique that directs light off the mirror surface and through the anterior teeth.

  • This method can highlight carious lesions as dark regions within the enamel of interproximal surfaces.

  • Both carious lesions and anterior restorations will appear as dark shadows when using this technique.

Limitations of Transillumination

  • Only anterior teeth can be properly transilluminated due to their thinner structure that permits light passage.

  • Posterior teeth, which are bulkier, cannot be transilluminated.

Procedure for Transillumination

  • Light Position:

    • Position the unit light directly over the oral cavity, ensuring the light beam is perpendicular to the facial surfaces of the anterior teeth.

    • The patient should be positioned with their chin down.

  • Position Mouth Mirror:

    • Clinician should position themselves at the 12:00 clock position.

    • Hold the mirror behind the mandibular anterior teeth with the reflecting surface parallel to the lingual surfaces.

  • View the Transilluminated Teeth:

    • Clinician should look directly at the teeth instead of in the mirror.

    • The teeth should appear to “glow” due to the light being reflected through them.

Note about Practicing Transillumination

  • When practicing transillumination on a student partner, it is typical not to observe any shadows on the teeth, primarily because they are unlikely to have untreated interproximal decay.

Example of Interproximal Decay

  • Detection of interproximal decay can be effectively achieved by transillumination.

  • It is important to note that when viewed with indirect vision, no decay may be visible on the lingual surfaces of the teeth.

  • However, transillumination can reveal interproximal decay appearing as shadows on the same surfaces.

  • This technique proves useful in identifying hidden decay on anterior teeth, showcasing the effectiveness of transillumination.