mandibular major connector (RPD)

Mandibular Major Connector

Relief on the fitting surface :

1 ) Tooth-tissue borne more relief than tooth borne

2 ) Vertical sloping of adjacent alveolar ridge : less relief

3 ) Horizontal sloping of adjacent alveolar ridge : more relief

4 ) Fulcrum line posterior to major connector : less relief

5 ) Fulcrum line anterior to major connector : more relief

6 ) Increased relief  when :

A ) Increased mobility of the abutment teeth

B ) Displaceable of residual ridge

C ) Poor bone quality

D ) Increased labial inclination of lower anterior teeth

Types of Mandibular Major Connector :

 1 ) Lingual Bar

2 ) Lingual Plate

3 ) Double Lingual Bar (Kennedy)

4 ) Labial Bar

Lingual Bar :

1 ) Functional depth of lingual sulcus : >= 8mm

2 ) 3mm from gingival margin

3 ) Half pear shaped cross section :

-superior-inferior  : 4-5 mm

-anterior-posterior : 2 mm

4 ) 3mm + (4-5mm) + 1mm

Lingual Plate :

1 ) Functional depth of sulcus : < 5 mm

2 ) Future loss of natural teeth anticipated

3 ) Lingual tori present

4 ) Posterior teeth have been loss and additional indirect retention is desired.

Double Lingual Bar (kennedy) :

1 ) Indicated primarily when contact with remaining mandibular anterior teeth is indicated, but open embrasures exist, and not indicated when crowding exist.

2 ) Tendency to trap food debris

3 ) Often irritate tongue

Labial Bar : 

1 ) When mandibular teeth severely inclined lingually

2 ) When large lingual tori present and cannot be removed

3 ) 3mm below gingival margin

4 ) Less rigidity because of longer extension