L2 Components of RPD Pt 1

Question 1

Major connector

Answer 1

the part of the RPD that joins the components of one side of the arch to this on the other side

Question 2

Direct retainer

Answer 2

the component used to retain the RPD and prevent dislodgment.

Question 3

Minor connector

Answer 3

the connecting link between the major connector of the RPD and the other units of the prothesis such as the clasp, assembly, indirect retainers, or rests

Question 4

Rest

Answer 4

a ridge extension of the RPD which contacts a remaining tooth in a prepared rest seat to transmit vertical and horizontal forces.

Question 5

Proximal plate

Answer 5

a rigid extension from the major connector or base which contacts the proximal surface of an abutment tooth

Question 6

Indirect retainer

Answer 6

assists the direct retainer in preventing displacement of the distal extension denture base by functioning through lever action on the opposite side of the fulcrum line when the denture base moves away form the tissues pure rotation

Question 7

Plastic retention area

Answer 7

part of framework to which the resin base is attached

Question 8

Denture base

Answer 8

part of denture that rests on the foundation tissues and to which teeth are attached

Question 9

What are the requirements of all major connectors (3)?

Answer 9

Sufficiently rigid, properly located, and must not impinge on the gingiva

Question 10

What are the design specifications of the maxillary major connector?

Answer 10

1. Borders 6mm+ from the gingival margin
2. When 6mm distance can’t be obtained the metal may be extended onto the cingula of the anterior teeth or onto the lingual surfaces of the posterior teeth
3. All borders should be tapered slightly to be less perceptible to the pt
4. in the rugae region, the borders should pass thru the valleys of the rugae, when possible
5. the posterior border should not extend onto the movable soft palate
6. usually no relief is required on the tissue surface. the tissue surface should not be highly polished to preserve intimate contact with soft tissue except where it crosses the gingival margin.
7. when future tooth los is anticipated, a plate type design may be used and extended onto the cingula of anterior teeth or lingual surface of posterior teeth
8. the border should be beaded. this is produced by scribing a rounded groove on the master cast approximately 3/4 to 1mm wide and deep.

Question 11

Anterior Palatal Strap Indications

Answer 11

1. Tooth borne RPD when ant teeth are missing (Class 4) or anterior and posterior teeth are missing (Class 3)
2. Maxillary tori cannot be covered

Question 12

Posterior Palatal Strap Indications

Answer 12

1. Tooth borne RPD when posterior teeth are missing

2. Tooth-mucosa borne RPD when minimal palatal support is required

Question 13

Rigidity may be increased by thickening the central portion to _______.

Answer 13

1.5mm

Question 14

Anteroposterior Palatal Strap Indications

Answer 14

1. May be used for tooth borne AND tooth mucosa borne RPD when replacement of anterior and posterior teeth is required and greater rigidity than the anterior palatal strap Is desired.
2. May be used when maxillary tori exist and rigidity is important
   * * the metal lying in two planes increases rigidity

Question 15

Modified palatal strap indications

Answer 15

1. tooth-mucosa borne RPD

2. complete palatal coverage is either not required or unacceptable to the pt

Question 16

Complete Palatal Plate indications

Answer 16

1. Long span bilateral tooth-musoca borne RPD with or without anterior teeth replacement
2. when maximum muco-osseous support is desired
3. may be used patients with naso-palatal defects

Question 17

What are the design specifications for the mandibular major connector?

Answer 17

1. superior borders 3mm+ from the gingival margins
2. if a 3mm distance cannot be obtained, the metal should extend onto the Cingula of the anterior teeth or the lingual surface of the posterior teeth
3. the metal should be highly polished on the tissue side to minimize plaque accumulation
4. relief of the tissue surface of the major connector is required to present tissue impingement during rest and function.

Question 18

How much relief should the mandibular major connector have?

Answer 18

Tooth borne –> 30 gauge
More relief is required for a tooth-mucosa borne RPD to accommodate the movement during function.
When the fulcrum line is POSTERIOR to the major connector, LESS relief is required (28-26 gauge)
When the fulcrum line is ANTERIOR to the major connector, MORE relief is needed (26-24 gauge).

Question 19

What is the criteria for selector of mandibular major connectors?

Answer 19

1. the location of the edentulous area
2. functional depth of the lingual vestibule
3. anticipated loss of natural teeth
4. inclination of remaining teeth.

Question 20

Lingual bar indications and specifications

Answer 20

1. functional depth >= 7mm.
2. gingival exposure is desired

half pear shaped/round in cross section. 4mm superior-inferiorly and 2mm antero-posteriorly. the superior borders should be at least 3mm away from the gingival margin. the inferior border may be placed at the functional depth of the lingual vestibule.

this is the simplest mandibular major connector with highest patient acceptance!

Question 21

Sublingual bar indications and specifications

Answer 21

1. functional depth of lingual vestibule is within 5-7mm
2. may be used whenever gingival exposure is desired but a lingual bar cannot be used because lack of vestibular depth

it’s essentially a lingual bar rotated 45-90 deg. the superior border should be at least 3mm away from the gingival margin. a functional impression is required to register the position and contour of the lingual vestibule. generally more rigid than the lingual bar in the horizontal plane.

Question 22

Lingual plate indications and specifications

Answer 22

1. functional depth <5mm
2. may be used when future loss of natural teeth is anticipated.
3. may be used when lingual tori are present

the superior border must positively contact the lingual surface of the teeth at or above the surgery line to avoid foot entrapment. the border should be thin without sharp edges. the superior border should extent interdentally to the contact points. in extension base RPD, the lingual plate should have a positive vertical stop (rest) on each side to prevent facial movement of the teeth.

the inferior portion is shaped like a lingual bar but may be thicker to increase rigidity. may deflect food from impacting on lingual tissues. may prevent or minimize extrusion of anterior teeth.

Question 23

Labial bar indications and specifications

Answer 23

Labial vestibular depth should allow superior border of labial bar to be at least 3mm away for the gingival margin.
Lacks rigidity since it is longer than a lingual bar.

1. may be used when the mandibular teeth are severely inclined preventing the use of a lingual major connector
2. may be used when large lingual tori exist and their removal is CI

Question 24

Cingulum bar

Answer 24

A metal bar resting on the lingual surfaces of the mandibular anterior teeth to aid in their stabilization and act as an indirect retainer. when used by itself, it is considered a Major connecter. rarely used due to lack of rigidity

Question 25

Minor connector design specifications:

Answer 25

1. a minimum of 1.5mm thickness is required at the junction of the minor connector and the rest for base metal alloys. for gold alloys 2mm is required.
2. relief is required when crossing the gingival tissues. in tooth - mucosa borne RPD, 30 gauge relief of the minor connector adjacent to the extension base and 32 gauge relief the other minor connectors. in tooth borne RPD, 32 gauge relief is sufficient.

Question 26

Minor connectors lingual and medial and distal angles..

Answer 26

LINGUAL minor connectors should cross the gingival tissues directly, joining the major connector at a RIGHT ANGLE.

The base of MESIAL and DISTAL minor connectors should swing back to join the major connector in a rounded ACUTE angle to increase gingival exposure.

Question 27

In tooth-mucosa borne RPD, relief should be provided on ________ teeth to permit minor connector movement during function. should be located at least ____ away from the other vertical components.

Answer 27

adjacent; 5mm