Clinical Assessment Of Vertical Dimension

What are the different methods of registering vertical dimensions? Differentiate vertical dimension at rest and vertical dimension at occlusion?
Answer:

Vertical Relations

The vertical jaw relations are those established by the amount of separation of the maxillae and mandible under specified conditions.

They are classified as:

1. The vertical dimension of occlusion
2. Of rest and
3. Other positions.

The vertical dimension of occlusion is established by the natural teeth when they are present and in occlusion (In edentulous patients it is established by the vertical height of the two dentures when the teeth are in contact).

Read And Learn More: Complete Dentures Question and Answers

The vertical dimension of rest (or physiologic rest position of the mandible) is established by muscles and gravity. The mandible is in its physiologic rest position when all the muscles that close and open the jaws are in a state of minimal tonic contraction sufficient only to maintain posture.

Significance Of Vertical Relations

• The value of the vertical dimension of rest position in denture construction lies in its use as a guide to the lost vertical dimension of occlusion.
• The difference between the occlusal vertical dimension and the rest vertical dimension is the interocclusal distance. The interocclusal distance is the distance or gap existing between the upper and lower teeth when the mandible is in the physiologic rest position.
• It usually is 2 to 4 mm when observed at the position of the first premolars. The clinically recorded rest position is not the same as the electromyographically determined one. A range of reduced muscle tension up to an interocclusal distance of about 10 mm has been reported.
• Failure to provide correct interocclusal distance will cause “clicking” of the dentures during the speech, soreness of the tissues of the basal seat, and rapid destruction of the residual alveolar ridges.

Recording Of Vertical Relations

Two recordings are done

1. Rest position
2. Occlusion position.

Methods for Recording Vertical Relations

1. Mechanical methods:

• Ridge relation distance of incisive papilla from mandibular incisors and parallelism of ridges.
• Measurement of former dentures.
• Pre-extraction records profile photographs, Lead wire adaptation, Face mask method by Swenson, Willis gauge, Dakometer, and articulated models.
• Post-extraction methods swingers method, the concept of equal thirds of the face, the Boos biometer, Silverman closest speaking space, and electromyography.

2. Physiologic methods:

1. Physiologic rest position
2. Phonetics
3. Esthetics
4. Swallowing
5. Tactile sense.

1. Recording Rest Position

Following are the few commonly used methods.

1. Facial Measurements:
   • Instruct the patient to stand or sit comfortably upright with the eyes looking straight ahead. Insert the maxillary record base with the attached contoured occlusion rim.
   • With either an indelible marker or a triangle of adhesive tape, place a point of reference on the end of the patient’s nose and another on the point of the chin.
   • Instruct the patient to wipe the lips with the tongue to swallow and to drop the shoulders. When the mandible drops to rest position and then measure between the points with a millimeter ruler. Repeat the procedure until the measurements are consistent.
2. Tactile Sense:
   • Then ask them to close slowly until the jaws reach a comfortable, relaxed position. The distance is measured between the points of reference and compared with the measurements made after swallowing.
3. Phonetics:

• • Have patients repeat “M” until they are aware of the contact of the lips as “M” is pronounced. Repeat this procedure and ask that they stop all jaw movement when the lips touch. At this time measure between two points of reference.

2. Occlusion Position Recording

 

Pre-extraction Records

1. Profile Photographs:
   • Measurements of anatomic landmarks on the photograph are compared with measurements using the same anatomic landmarks on the face.
2. Profile Silhouettes
3. Facial Measurements.

Niswonger’s Method

The distance is measured and these measurements are compared with measurements made between these points when the occlusal rims are tried in.

1. Closest speaking space

The closest speaking space measures vertical dimension when the mandible and muscles involved are in the physiologic function of speech. The ‘F’ or ‘V’ and ‘S’ syllables are used in locating closes speaking space.

2. Swallowing followed by Relaxing

• With a denture in the mouth, instruct the patient to wipe the lips with the tip of the tongue, swallow and let the shoulders drop in a relaxed position.
• Watch the reference points and ask the patient to close the teeth together. If the teeth are together, it can indicate that no interocclusal distance exists.
• Another method is based on the theory that teeth make contact at or near centric occlusion. Two small cones of a soft wax are placed, one in each central sulcus of the mandibular first molars.
• Encourage the patient to swallow several times. If the vertical dimension of occlusion is correct, the wax will be penetrated and reduced to tooth contact.

3. Phonetics

Have the patient repeat these words:

• “Three thirty-three” there should be enough space for the tip of the tongue to protrude between the anterior teeth.
• “Fifty-five” incisal edges of the maxillary central incisors should contact the vermilion border of the lower lip at the junction of the moist and dry mucosa.
• “Emma and Mississippi” the teeth should not contact.

Following are some of the tests when the occlusion rims are placed in the mouth:

1. Judgment of the overall facial support.
2. When the patient closes the jaw slowly until the lips just touch, at this point, the mandible is at rest position. The lips are in constrained contact.
   • Next, ask the patient to close the jaw so that in closing through the interocclusal distance there is little or no movement of the lips.
   • If the patient has decreased vertical relation that is increased interocclusal distance, the lips close excessively, fold together and vermilion tend to disappear.
3. Visual observation of the amount of space between the rims when the jaws are at rest.
4. Measurements between dots on the face when the jaws are at rest and when occlusion rims in contact.
5. Observation is made when sibilant-containing words are pronounced to ensure that the occlusion rim comes close together but does not contact.