Mand. major connecter ppt - د. عمر زينو التحو

Special Structural Requirements of Mandibular major connectors:

1. relief must be routinely provided between mandibular major connector and the soft tissue. 2. because of the need for relief under all mandibular major connectors, Beading is never indicated. Amount of relief depend on:

Six types of mandibular major connectors are: l. Lingual bar 2. Linguoplate 3. Sublingual bar 4. Cingulum bar (continuous bar) 5. Lingual bar with cingulum bar (kennedy bar, double lingual bar) 6. Labial bar

1-Lingual Bar

Characteristics and location (1) Half-pear shaped with bulkiest portion inferiorly located. (2) Superior border tapered to soft tissue. (3) Superior border located at least 4 mm inferior to gingival margins and more if possible. (4) Inferior border located at the ascertained height of the alveolar lingual sulcus when the patient's tongue is slightly elevated.

Indication: It is the first choice major connector, should be used whenever the functional depth of the lingual vestibule equal or exceed 8mm Contraindications: 1- insufficient space between the gingival margin and the floor of the mouth. 2- presence of tori that can not be surgically removed. 3.presence of high lingual frenum attachment.

Advantages of lingual bar : simplicity in design lingual bar has minimal contact with oral tissues. it does not contact teeth, so decalcification of tooth surface because of food or plaque accumulation does not occur. Rigidity Disadvantages:

2- MANDIBULAR LlNGUOPLATE ( Lingual plate)

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Characteristics and Location (1) Half-pear shaped with bulkiest portion inferiorly located. (2) Thin metal apron (sold piece) extending superiorly to contact cingula of anterior teeth and lingual surfaces of involved posterior teeth at their height of contour. (3) Apron extended interproximally to the height of contact points, i.e., closing interproximal spaces.

(4) Scalloped contour of apron as dictated by interproximal blockout. (5) Superior border finished and knife edged to continuous plane with contacted teeth.

(6) inferior border at the ascertained height of the alveolar lingual sulcus when the patient's tongue is slightly elevated

lingual plate must be supported by rests located no farther posterior than the mesial fossae of first premolars

Indications 1.When the functional depth of the lingual vestibule (less than 5mm) is not enough for bar placement. 2.When future loss of natural teeth is anticipated to facilitate addition of artificial teeth to the partial denture. 3.When splinting of anterior teeth is required. 4.When lingual tori is present. 5. in Class I undergone such vertical resorption 6.when most posterior teeth have been lost and there is need for indirect retainer.

One of the greatest advantages of the lingual plate major connector is its exceptional rigidity. In addition, patients often consider a well-fitting lingual plate more comfortable than a lingual bar.
Disadvantages Extensive coverage of teeth and soft tissue may contribute to decalcification of enamel surfaces or irritation of soft tissue if the patient has poor oral hygiene.

lingual plate may include "step backs" to minimize or eliminate the appearance of metal.

3. Sublingual bar major connector

3- Sublingual bar major connector Characteristics and Location A modification of the lingual bar that has been demonstrated to be useful when the height of the floor of the mouth does not allow placement of the superior border of the bar at least 4 mm below the free gingival margin is the sublingual bar. The bar shape remains essentially the same as that of a lingual bar, but placement is inferior and posterior to the usual placement of a lingual bar, lying over and parallel to the anterior floor of the mouth.

Indications for Use 1.The sublingual bar should be used for mandibular removable partial dentures where the height of the floor of the mouth in relation to the free gingival margins will be less than 6 mm. It may also be indicated whenever it is desirable to keep the free gingival margins of the remaining anterior teeth exposed and there is inadequate depth of the floor of the mouth to place a lingual bar. 2. the lingual frenum does not interfere with sublingual bar. 3. in the presence of an anterior lingual undercut that would require considerable blockout for a conventional lingual bar.

Contra indications for Use 1. remaining natural anterior teeth severely tilted toward the lingual. 2. interfering lingual tori. 3. high attachment of a lingual frenum, interference with elevation of the floor of the mouth during functional movements.

4.CINGULUM BAR (continuous bar)

CINGULUM BAR (continuous bar)
Characteristics and location (l) Thin, narrow, ( 3 mm) metal strap located on cingula of anterior teeth, scalloped to follow interproximal embrasures with inferior and superior borders tapered to tooth Surfaces. (2) Originates bilaterally from incisal , lingual, or occlusal rests of adjacent principal abutments.

Indications for Use 1. the axial alignment of the anterior teeth is such that the excessive blockout of interproximal undercuts would be required. 2. when wide diastemata exist between the lower anterior teeth, a continuous bar retainer may be more esthetically acceptable than a linguoplate. Contraindications for Use Anterior teeth severely tilted to the lingual

5. MANDIBULAR LINGUAL BAR WITH CINGULUM BAR(Double lingual bar, Kennedy bar)

MANDIBULAR LINGUAL BAR WITH CINGULUM BAR (Double lingual bar, Kennedy bar) Characteristics and location (1) Conventionally shaped and located Same as lingual bar major connector component when possible. (2) Thin, narrow (3 mm) metal strap located on cingula of anterior teeth, scalloped to follow interproximal embrasures with inferior and superior borders tapered to tooth surfaces. (3) Originates bilaterally from incisal, lingual, or occlusal rests of adjacent principal abutments

MANDIBULAR LINGUAL BAR WITH CONTINUOUS BAR (CINGULUM BAR )

Indication for Use (1) When a Iinguoplate is otherwise indicated but the axial alignment of anterior teeth is such that excessive blockout of interproximal undercuts would be required . (2) When wide diastemata exist between mandibular anterior teeth and a linguoplate would objectionably display metal in a frontal view

Advantages indirect retention in an anterior direction. It also contributes to horizontal stabilization of the prosthesis 2. the gingival tissues and the interproximal embrasures are not covered .

Disadvantages 1. double lingual bar is its tendency to trap debris. 2. double lingual bar irritating to the tongue. 3. The presence of multiple borders and the thickness of the upper bar are often annoying.

MANDIBULAR LABIAL BAR

Characteristics and location (1) Half-pear shaped with bulkiest portion inferiorly located on the labial and buccal aspects of the mandible. (2) Superior border tapered to soft tissue. (3) Superior border located at least 4 mm inferior to labial and buccal gingival margins and more if possible. (4) Inferior border located in the labial -buccal vestibule at the junction of attached (immobile) and unattached (mobile) mucosa.

MANDIBULAR LABIAL BAR Indication for Use (1) When lingual inclinations of remaining mandibular premolar and incisor teeth cannot be corrected, preventing the placement of a conventional lingual bar connector. (2) When severe lingual tori cannot be removed and prevent the use of a lingual bar or lingual plate major connector. (3) When severe and abrupt lingual tissue undercuts make it impractical to use a lingual bar or lingual plate major connector. Indications for it are extremely rare .

The swing-lock design is a variation of the labial bar. Hinge at one end and locking device at the opposite end.

disadvantages 1. Patient acceptance of labial bar major connectors generally is poor. 2. The bulk of the major connector distorts the lower lip 3. present of metal between the gingival tissues and the lip causes significant discomfort.

Review for indications for mandibular major connector: 1.For tooth-supported RPD : LINGUAL BAR is indicated. 2. If less than 8 mm exist between gingival margin and floor of the mouth, or in case of presence of tori : LINGUOPLATE is indicated. 3.When anterior teeth have reduced periodontal support: LINGUOPLATE is indicated. 4.Low periodontal support for anterior teeth with large interproximal spaces : LINGUAL BAR WITH CONTINUOUS BAR RETAINER is indicated . 5.replacement of all posterior teeth and indirect retention is needed: LINGUOPLATE is indicated. 6.The Labial Bar is rarely indicated

Determination of the relative height of the floor of the mouth

1.By the use of Periodontal probe to measure the height of the floor of the mouth in relation to the lingual gingival margins of adjacent teeth. In this method the tip of the patient's tongue should be just slightly touching the vermilion border of the upper lip. 2.By the use of an individualized impression tray having its lingual borders 3mm short of the elevated floor of the mouth and then to use an impression material that will permit the impression to be accurately molded as the patient touches the lip. The inferior border of the planned major connector can then be located at the height of the lingual sulcus of the cast resulting from such impression.