Major and Minor Connectors Flashcards
What is a major connector?
Rigid structure that joins the components on one side of the arch with those on the opposite side.
All other RPD components are either directly or indirectly attached to it.
What is the function of the major connected in an RPD?
Union of RPD components
Distribution of applied force throughout the arch to selected teeth and tissues
Minimization of torque to individual teeth
Control prosthesis movement (Cross-arch stability)
Assist indirect retention
Why should a major connector be rigid?
A flexible major connector would cause damage to hard and soft tissues.
It would allow forces to be concentrated on individual teeth and segments of residual ridges resulting in tooth mobility and loss, bone resorption leading to decreased support for associated denture bases.
Why should a major connector be in a favourable location?
To avoid impingement of gingival tissues (gingival margin)
Avoid tori and soft tissue prominences
Relief beneath major connector in areas of possible interferences
To be free of movable tissue
What are the important features of a major connector?
Rigidity
Favourable location
Rounded angles
Borders of major connector far from the gingival margin
Maintain the natural contour of subadjacent structures
How far should the major connector be from the gingival margin?
Mandible = 3 - 4 mm
Maxilla = 5 - 6 mm
What are the features of good major connectors?
Intimate contact of major connector and palatal mucosa improve retention and stability.
Lower the periodontal support the greater the palatal coverage.
The wider the major connector the thinner it can be the narrower it is the thicker it should be.
What are the types of majjor connectors?
Single palatal strap
Antierior-posterior strap or palatal plate
U-shaped palatal corridor
Broad palatal strap or palatal plate
Single palatal bar
Anterior-posterior palatal bar
When is a single palatal strap used?
Class III +/- mod (no anterior mod)
What are the design features of the single palatal strap?
Thin for tongue comfort but wide (>=8mm) enough for rigidity
Anterior border should follow the valleys but avoid cutting across the rugae
Anterior and posterior borders cross the suture line at right angles
When is an anterior-posterior palatal strap used?
Class II, III with anterior mod, IV
What are the design features of an anterior-posterior palatal strap?
Flat and at least 8mm wide
Posterior strap should be anterior to the hard/soft palate limit
When should the anterior-posterior palatal strap be avoided?
Inoperable torus extending to soft palate
When is a U-shaped palatal connector used?
Inoperable large palatal torus
Common with class IV
Significant gag reflex
What are the problems with the U-shaped palatal connector design?
Poorest design for rigidity
Bulk is often required where tongue space is needed (the most freedom is required in the rugae zone)
When is palatal plate or gull palatal coverage used?
Few remaining teeth such as only the anterior arrangement
Teeth with poor prognosis
Long, flat residual ridges
What are the design features of a single palatal bar?
Narrow
Cross-section is a half-oval shape
< 8mm in width
Class III with small edentulous area
What are the single palatal bar disadvantages?
Bulky - Discomfort, not to be placed anterior to the 2nd PM
Low vertical support
Where is the single palatal bar placed?
Anterior: located in the area of palatal rugae
Median: Behind palatal rugae (ideal)
Posterior: Placed in the limit hard-soft palate
What is an anterior-posterior palatal bar?
Combination of anterior and posterior bars. Anterior bar is more flat.
Has 2 longitudinal elements connecting the anterior bar to the posterior bar.
Replaces many teeth.