Major and Minor Connectors Flashcards
What is the major connector?
That component of a partial denture which joins the minor connectors and their attached assemblies together to form a solid unit
What is cross-arch stabilization?
Bracing elements on one side of the arch providing stability to the other
What is the purpose of the major connector?
- counter leverage
- cross-arch stabilization
- unification of components
Why does the major connector need to be rigid?
- functions as one unit
- broad stress distribution
- reduce torque
- avoid tissue damage
The major connector should or should not interfere with tissues?
should not!
How do you make sure that the major connector does not interfere with tissues?
- blockout the undercuts (change path of insertion)
- avoid terminating in the…
–free gingival margin
–lingual frenum
Should any part of the major connector end at the free gingival margin?
NO
To avoid terminating at the free gingival margin the major connector should cross at ____ degrees
90 degrees
How do you minimize food impaction on a major connector?
- Locate margins away from the FGM
- Eliminate “traps” or large concavities where food can collect
Smooth transition from connector to denture base is called…
butt joint
Borders are placed parallel to and a minimum of __ mm from gingival margins on the maxilla
6
Anterior borders on maxilla follow valleys between…
rugae
Anterior & posterior borders cross
midline at _______ angle
right
Borders beaded on major connector on the maxilla at…
0.75-1.0 mm wide & deep
What area should you avoid on major connectors?
- 6mm from gingival crest (Maxillary)
- 3mm from gingival crest (Mandibular)
- Tissue impingement
- Ending on crests of rugae
- Irritation of surface eminences during insertion/removal
- Ending on incisal 1/3 of anterior teeth
- Food impaction
- Occlusal interferences
- Speech interference
- Gagging
- Tongue irritation
When do you need a palatal strap?
- Tooth supported situations - Class III
- Small posterior edentulous areas
- Minimal tissue support required
- Patient preference
How thick is a palatal strap?
8-10 mm
When do you not use a palatal strap?
- Distal extension situations – Class I or II
- Severe palatal undercuts
- Large torus
- RPD to replace anterior teeth
- When definitive support from palatal tissue is required
What are the different types of maxillary major connectors?
- palatal strap
- palatal plate
- anterior-posterior strap
- Horseshoe or “U”
What are the advantages of a palatal strap?
- Excellent support and rigidity
- Distribute stress of mastication over a wider area
What are the disadvantages of a palatal strap?
Coverage of palate may cause discomfort and interference with phonetics
Where should the palatal strap be located?
- Anterior border follows valley between rugae at right angle to median suture
- Posterior border at right angle to median suture
Where is the anterior border of the palatal strap located?
valley between rugae at right angle to median suture
Where is the posterior border of the palatal strap located?
right angle to median suture
When should you use a palatal plate?
- Long-span distal extension RPDs with or without anterior tooth replacement
- Flat residual ridges
- Periodontally weakened abutments
When do you not use a palatal plate?
- Severely undercut torus
What are the advantages of a palatal plate?
- Optimum support and rigidity
- Increase retention due to increased interfacial surface tension
What are the disadvantages of a palatal plate?
- Can not be used with torus
- Coverage of the palate may diminish taste, interfere with phonetics.
- Difficult to cast
Where is the location of the palatal plate?
- Anterior border between rugae valleys and at right angle to median suture
- Posterior border: Extends to junction of soft and hard palate
Where is the anterior border of the palatal plate located?
between rugae valleys and at right angle to median suture
Where is the posterior border of the palatal plate located?
junction of soft and hard palate
When should you use a anterior-posterior palatal strap?
- Circumvent a torus
- Strong, widely separated abutments (Distal extension RPDs; Distal extension RPDs also replacing anterior teeth)
When should you not use an anterior-posterior palatal strap?
- SOME maxillary designs due to narrow bulky straps
- Patients with high narrow vaults
- Phonetic interference
The space between the anterior and posterior straps on an anterior-posterior palatal strap connector should be?
15 mm
What are the type of acrylic holdy things?
lattice, mesh, bead
What are the advantages of the anterior-posterior palatal strap?
- Structurally, very rigid - straps in 2 planes
- Minimal tissue coverage
How wide should the anterior and posterior straps be on the anterior-posterior palatal straps?
6-8 mm
Where should the posterior part of the anterior-posterior palatal strap be located?
– distal extension to vibrating line and extended through hamular notches
– tooth supported not more posterior than distal abutment
When do you use a horseshoe or U-shaped maxilla major connector?
- **In very high vault palate **
- Large inoperable torus
- Anterior tooth replacement
- Patient is intolerant of palatal coverage
What is the problem with the horseshoe or U-shaped maxilla major connector?
The Least Rigid maxillary connector, therefore ANYTIME another connector can be used then it should
What are the advantages of the horseshoe or U-shaped maxilla major connector?
- Can be designed to replace missing anteriors
- Conforms to patient’s previous experience
What are the disadvantages of the horseshoe or U-shaped maxilla major connector?
- Requires additional bulk for rigidity
- Can interfere with patient’s tongue/speech
- Even with rest, may lack support causing possible tissue impingement
Where is the anterior border of the horseshoe major connector?
– terminates in valley of rugae at right angle to suture
– on the cingula of teeth extending contact point to contact point
Where is the posterior border of the horseshoe major connector?
located at the turning point of the palate
What is beading of the maxillary cast?
- A prepared groove on the master cast along the designated borders of maxillary major connectors
- This produces a positive bead on the major connector of the RPD
What are the functions of beading on the maxillary cast?
- Increased rigidity
- Guide for finishing
- Compensates for casting inaccuracies
- Displaces soft tissue, preventing food/fluid collection
What are the mandibular major connectors?
Lingual bar
Lingual plate
Labial bar
What are the reasons to use a lingual bar mand major connector?
- Whenever possible, if no contraindications are evident
- A depth of at least 7 mm measured from the lowest point of the gingival margins to the floor of the mouth is required
A depth of at least __ mm measured from the lowest point of the gingival margins to the floor of the mouth is required for a lingual bar
7
When would you not use a lingual bar major connector?
- Shallow floor of mouth and prominent frenum
- Inoperable tori
- Teeth in linguoversion
- Teeth require stabilization
- RPD requires additional stabilization
- RPD requires benefit of additional indirect retention
- Contingency planning
What is the reason lingual bar is the preferred major connector for mand?
Covers the minimum of the tissues
What is the disadvantage of the lingual bar major connector?
It may be flexible if poorly constructed
Where should the superior border of the lingual bar be located?
3 mm inferior to free gingival margin
What is the bar height for the lingual bar?
4 mm
Where is the inferior border of the lingual bar located?
at height of lingual sulcus with tongue slightly elevated
When would you use a lingual plate?
- Insufficient lingual vestibular space for lingual bar (less than 7 mm)
- Anticipated future replacement of anterior teeth
- Indirect retention
- Bilateral distal extension with flat residual ridges (Provide resistance against horizontal movements)
- Presence of mandibular tori
- Patient preference
When would you not use the lingual plate?
- Adequate depth to floor of the mouth for a bar
- Prominent diastemas (large interdental spaces)
- Severely anterior crowding
- Patient preference
- Teeth in linguoversion
What is the advantage of the lingual plate over the lingual bar?
more rigid than lingual bar
What are the disadvantages of the lingual plate?
- Covers teeth and tissue
- Compromised oral hygiene “possible increase enamel decalcification”
- Esthetic with diastemas
Where is the superior border of the lingual plate located?
contacts cingula of anterior teeth extending from contact point to contact point
Where is the inferior border of the lingual plate located?
at height of alveolar lingual sulcus with tongue elevated
What is another name for this type of RPD besides labial bar?
gate
swing lock
When would you use a labial bar major connector?
- Lingually inclined anterior or posterior teeth
- Prominent, superiorly located inoperable tori
What is the disadvantages of the labial bar major connector?
-Difficult to fabricate
-Must be bulky to be rigid
-Not esthetic
-Traps food in vestibular area
What is a minor connector?
That component of a partial denture which joins the major connector with other parts of the framework
What does the minor connector join to the major connector?
– the clasp assembly
– indirect retainers or auxiliary rests
– the denture base
What serves as an approach arm for a vertical projection or bar type clasp?
minor connector
What are the functions of a minor connector?
- Transfers functional stress to abutments
- Transfers effect of retainers, rests and stabilizing components to the rest of the denture (abutment to prosthesis)
- Unites retainers, rests and denture base to the major connector
- Helps to resist lateral movement
What are the requirements of a minor connector?
- Rigid with minimal bulk
- Located in embrasure
- Triangular in shape
- Thickest toward lingual
- Joins major connector at right angle
- Tapers to contact point
- Smooth and rounded
- Minimum of 5mm between vertical connectors
- Cover minimal gingival tissue
- Cross gingiva at right angle
- Must not impinge on tissue
- Contact guiding plane surfaces
- Minimal interference with denture tooth placement
What is the difference between minor connectors and proximal plates?
