Intermaxillary Registration and Vertical Dimension in Dentures
Intermaxillary Registration in Dentures
Vertical Dimension
A measurement of the lower third of the face using two arbitrary points: one above the superior lip and one below the inferior lip.
Vertical Dimension at Rest (Postural)
The measurement of the lower third of the face when the levator and depressor muscles of the jaw are in minimum tonic contraction to maintain the jaw position against gravity. In this state, the dental arches are not touching, the lips have a soft contact, and the teeth are separated by an inter-occlusal space (freeway space) typically measuring 2 to 4 mm.
Vertical Dimension in Occlusion
The measurement of the lower third of the face when the teeth are in contact. The lips are in contact, and there is no inter-occlusal space. This dimension can be affected by:
- Loss of a significant number of teeth or total edentulism
- Tooth decay
- Tooth migration
- Occlusal wear
Disorders Caused by Reduced Vertical Dimension
- TMJ disorders
- Decreased masticatory efficiency
- Increased perioral furrows
- Sinking of the lips
- Angular cheilitis
Disorders Caused by Increased Vertical Dimension
- TMJ disorders
- Muscle fatigue
- Periodontal trauma
- Marked bone resorption
- Decreased masticatory efficiency
- Difficulty in speaking
Procedure for Total Denture Formulation
- Anatomic impression (materials and instruments)
- Selection of the tray
- Mixing alginate and taking impressions
- Study models
- Design of individual trays
- Functional impression (materials and instruments)
- Peripheral seal
- Mercaptan handling techniques
- Working models
Measurements for Joint Plates
Superior Plate
The posterior wax rim, distal to the hamular notch, should measure 10 mm.
Inferior Plate
- Anteriorly, from the edge of the joint plate to the occlusal surface of the wax rim, it should measure 18 mm.
- Posteriorly, the wax rim should be 2 to 3 mm below the top of the retromolar pad (approximately 1/3 of the anatomical landmark).
Anatomical References for Rim Height
- Superior jaw joint plate orientation
- Upper occlusal plane orientation
- Centric relation determination (interpupillary line, Camper's plane, plane of occlusion)
- Transfer to the lower level of occlusion
Methods for Checking Vertical Dimension
Willis Gauge
Place the rule on the middle third of the face and measure the distance from the glabella to the base of the nose.