Prosthodontics MCQ Answer 51

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CORRECT ANSWER: D. is true

a. is false. Rigidity of the major connector resists flexing and torque that would be otherwise be transmitted to abutment teeth or other structures as destructive forces.

b. is false. A major connector is the unit of the partial denture that connects the parts of the prosthesis located on one side of the arch with those on the other side. It is the unit of the RPD which other all other parts are directly or indirectly attached.

c. is false. The linguoplate should be something that is added to, and not something that replaces the conventional lingual bar. The linguoplate and the continuous bar retainer should ideally have a terminal rest at each end regardless of the need for indirect retention.

Indications for a linguoplate are:

1. when the lingual frenum is high or the space available for a lingual bar is limited.

2. in class I situations in which the residual ridges have undergone excessive vertical resorption.

3. for stabilizing periodontally weakened teeth.

4. when the future replacement of one or more incisor teeth will be facilitated by the addition of retention loops to an existing linguoplate.

There are six types of mandibular major connectors. These include: lingual bar, sublingual bar, lingual bar with cingulum bar (continuous bar) retainer, cingulum bar, Linguoplate and labial bar.

There are four basic types of maxillary major connectors. These include: single palatal bar, single palatal strap (U-shaped palatal connector), anterior-posterior palatal bars, combination anterior and posterior palatal strap-type connector.

Components of a typical removable partial denture include major connector, minor connectors, rests, direct retainers, stabilizing or reciprocal components (these serve as parts of a direct retainer assembly), indirect retainers (if the prosthesis has one of more distal extension bases), and one or more bases (each one supports one or more teeth).

Minor connectors arise from the major connector, and unites the major connector with other parts of the denture.

The minor connector may be continuous with some other part of the denture. An occlusal rest at one end of a linguoplate is actually the terminus of a minor connector, even thought that minor connector is continuous with the linguoplate.

Also, the portion of a denture base frame that supports the clasp and the occlusal rest is a minor connector, joining the major connector with the clasp.

The portions of the framework by which the denture bases are attached are minor connectors. The minor connector serves two purposes, which are diametric in function.

The first is to transfer functional stress to the abutment teeth.

Occlusal forces applied to the artificial teeth are transmitted through the base to the underlying ridge tissues if that base if primarily tissue supported.

Occlusal forces applied to the artificial teeth are also applied to the abutment teeth through occlusal rests.

This is called prosthesis-to-abutment function of the minor connector.

The second is to transfer the effect of the retainers, rests, and stabilizing components to the rest of the denture. This is abutment-to-prosthesis function of the minor connector.

References:

McGinvney and Castleberry: Mc Cracken’s Removable Partial Prosthodontics, 9^th Ed., Mosby 1995.