mandibular major connectors
Post on 03-Dec-2015
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DESCRIPTIONmandibular major connectors
Mandibular major connectorsDr.Mohammad Al Sayed
7 / 3 / 1429
1-The superior borders are placed at least 3 mm from the gingival margins. where a 3 mm cannot be obtained so, the metal should extend onto the cingula of anterior teeth or onto the lingual surfaces of posterior teeth. 2-The inferior border should not interfere with the soft tissue movement of the floor of the mouth. 3-Relief of the tissue surface of the major connector is required to prevent tissue impingement at rest or during function. 4-The metal should be highly polished on the tissue side to minimize plaque accumulation.
Types of mandibular major connectorsI-lingual bar.II-sublingual bar.III-double lingual bar.IV-lingual plate.V-labial bar.
I-Lingual bar. Indication:It is the first choice major connector, should be used whenever the functional depth of the lingual vestibule equal or exceed 8mm.Design:1.the bar should be half pear-shaped in cross section. superior inferior dimension is 5 mm ,and 2 mm in thickness.2.the superior border of the bar should be located at least 3 mm from the gingival margins of all adjacent teeth.3.the inferior border placed at the functional depth of the lingual vestibule.4.relif of the tissue surface of the bar is necessary
Advantages:1.the simplest mandibular major connector with highest patient acceptance.2.it does not cover the teeth or the gingival tissues
disadvantages:If it is not properly designed it may not be rigid.
2.Sublingual barIndications:When the lingual bar cannot be used because the of a lack of functional depth of the lingual vestibule.
Design:1.The sublingual bar is essentially a lingual bar rotated horizontally.2.The superior border of the bar should be located at least 3 mm from the gingival margins of all adjacent teeth.
Advantages:1.It does not covers the teeth or tissues.2.More rigid than a lingual bar in the horizontal plane.
Disadvantages:A functional impression of the vestibule is required to accurately register the position and contour of the vestibule.
3.The double lingual bar:Indications:1.When indirect retention is required.2.When periodontally affected teeth that require splinting are present.Design:1.It is made of two bars; cingulam bar (Kennedy bar) and the conventional lingual bar. A rigid minor connector at the embrasure between the canine and first premolars joins the two bars. Rests are placed at each end of the upper bar attached to the minor connector.2.The lower bar has the same design as a single lingual bar.3.The upper bar is scalloped, and half-oval in cross section (2-3 mm high, and 1 mm thick at its greatest diameter.
Advantages:1.Provides indirect retention.2.Contributes to horizontal stabilization.3.No gingival margin coverage.
Disadvantages:1.Tongue annoyance.2.Food impaction if the upper bar is not in intimate contact with the teeth.
4.Lingual plateIndications: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.
Design:1.It consists of a pear shaped lingual bar with a thin metal extending upward from the superior border of the bar onto the lingual surfaces of the teeth above the cingula and survey lines. 2.In extension base partial denture the lingual plates should have a rest on each side to prevent labial movement of the teeth.3.There should be adequate blockout and relief of the soft tissue undercuts, undercuts in the proximal areas of the teeth, the free gingival margins and pear shaped bar.
Advantages:1.The most rigid mandibular major connector.2.It gives indirect retention to the partial denture.3.Deflect food from impacting on lingual tissues.4.Provide resistance against horizontal or lateral forces.5.Permits the replacement of lost teeth without remaking the partial denture.6.Help in splinting and prevent upper-eruption of the anterior teeth.Disadvantages:Covers more teeth and gingival tissues than other mandibular major connectors.
5.Labial barIndications:1.When the mandibular teeth are so severely inclined lingually as to prevent the use of lingual major connector.2.When large lingual tori exist and their removal is contraindicated.Design:1.It is a half pear shaped bar, runs across the mucosa labial to the anterior teeth.2.Labial vestibule should be adequate to allow the superior border to be placed at least 3 mm below the free gingival margins. 3.Relief is required beneath the bar.
Advantages:It solves the problem of severely inclined teeth and avoids surgical intervention to remove large torus.
Disadvantages:1.It tends to lack rigidity since it is considerably longer than a lingual bar. 2.The least comfortable mandibular major connector.