RPD system of design: connectors Flashcards
What are connectors
a term used to describe the rigid part of a partial denture that unites other components
what are the two types of connectors
major and minor
What do minor connectors do
- join component such as rests to the major connector
- transfer functional stresses to and from the abutment teeth
What should the characteristics of minor connectors be
- rigid
- finish above (towards occlusal surface) the survey line on teeth
- cross the gingival margin at right angles (to maintain gingival health)
- cover as little gingival tissue as possible
- avoid multiple ‘windows’
What does a major connector do
- connects components on one side of the arch to components on the other side of the arch
What are the guidelines for a major connector
- rigid
- avoid covering gingival margins
- comfortable (as few edges as possible)
- cover as little tissue as is consistent with rigidity
what modifications can be made for major connector
- base distribution
- need for tissue support
- need for indirect retention
- anatomical limitations
- prognosis of the dentition (can modify to allow for extra tooth/teeth to be added)
- previous denture influence (don’t fix things if they are happy the way things are)
What are the two kinds of major connectors
plates/strap
bar
What is the main advantage of plates
can be made thinner in cross-section and still maintain rigidity (can be as little as 0.5mm)
When would you opt for a plate over a bar
mucosa supported designs
In what instance is a plate design recommended in the mandibular arch? why?
when there is no space availiable for a bar (plate designs may cover gingival margins)
What is the main advantage of a bar
less mucosal coverage
what is the main disadvantage of bars
need to be thick e.g. a lingual bar should be 2mm thick
For what craddock classification are bars the common choice
class 1, also mandibular arch as little space
What are the choices for upper metal connectors
Anterior palatal strap Mid-palatal strap Posterior palatal strap Arterior and posterior strap (ring) Full palatal coverage
What are the choices for upper acrylic maxillary connectors
anterior palatal strap mid-palatal strap posterior palatal strap anterior and posterior strap (ring) horseshoe full palatal coverage
Names of 3 common maxillary connectors (acrylic)
“spoon”
“modified spoon”
“Every”
Common mandibular connectors (metal)
lingual bar lingual plate dental bar sublingual bar labial bar (rare)
What is pretty much the only instance you’d use a labial bar
only when lower anterior teeth are lingually inclined therefore preventing lingual bar
Where should mandibular bar connectors be positioned ideally (and how much space do you need in total)?
at least 3mm below gingival margin on lingual side, 1 mm clearance to functional floor of mouth
8mm in total (4mm height of bar)
What is the strongest type of bar
anterior and posterior (ring)
Advantages of a anterior and posterior ring
- little coverage of gingival tissue
- a rigid connector
- wide relief of gingival margins to prevent food impaction
Disadvantages of an anterior and posterior ring
- less support to the free-end saddle across the hard palate (narrow coverage)
- lots of edges that some patients might find uncomfortable
- greater cross-sectional thickness
Advantages of full palatal coverage (metal)
- a rigid connector
- wide relief of gingival margins to prevent food impaction
- support across the hard palate for the free end saddle
- less edges that patient might find uncomfortable
- thinner cross section
