8.pdf

Ministry of Higher Education and Scientific Research. Al-furat Al Awsat Technical Institute Najaf Technical Institute Department of Dental industery Partial Denture FIRST STAGE lecture Eight Component part o...

Ministry of Higher Education and Scientific Research. Al-furat Al Awsat Technical Institute Najaf Technical Institute Department of Dental industery Partial Denture FIRST STAGE lecture Eight Component part of partial denture Major conector Maxillary &Mandibular Major conector Preparation BY Baeda hasoon salman  Major connector Major connector: It's that part of partial denture which is connecting the (lift side of the arch to the right side). 1-Maxillary Major Connector. 2-Mandibular Major connector. Maxillary Major Connector: 1-Single posterior palatal Bar: It is use in a tooth born unilateral or bilateral limited spaces for cross arch stabilization. The decision to use a single palatal bar instead of a strap should be based on the size of the denture-bearing areas. Indication for : A-Maxillary tooth born posteriorly partial denture. b-Where there is unilateral (free end extension).the bar should be wide non flexible with the central portion thicker than the edges, this provide strength. 2-Single anterior palatal Bar: Its U shaped or horse shoe shaped, it is the more desirable of maxillary major connector used.  Indication: Hard midline palatine suture. Prominent maxillary torus palatines. When several anterior teeth to be replaced. 3-Palatal plate or strap: It is a wide palatal strap, it could be made wide to become thinner and helps in the distribution of the mastication forces over a wide area, and it is less objectionable by the patient Indications: Bilateral and unilateral edentulous spaces of short span in a toothsupported restoration (CL III & CLIII mod 1). Contraindications: 1. Tooth- tissue supported removable partial denture (RPD). 2. Palatal torus. 3. Extremely long tooth supported edentulous space. 4- Combination anterior and posterior palatal bar: Its composed of an anterior and posterior palatal bar The anterior component is a flat bar located as far as possible from the rugae area and tongue interference (6 mm away from gingival margins) while the posterior bar is a half oval in cross section located as far as possible The advantages of this type: a-Each portion made thinner and narrower than single bar. B-It has strong as possible to avoid interference with the tongue. 4- Combination anterior and posterior palatal strap type major connector:- t is a rigid palatal major connector. The anterior and posterior palatal strap combination may be used in almost any maxillary partial denture design. forming a square or rectangular frame and open in center portion. 5- Full coverage plate palatal plate are used to designate any thin, broad, contoured palatal coverage used as a maxillary major connector and covering one half or more of the hard palate. Posterior border at the junction of the hard and soft palates; It covers a wide area of the palate so it contributes in the support and retention of the prosthesis, this coverage permit a wide distribution of the functional load with very little movements from the base during function thus reducing horizontal forces which are highly destructive specially to abutment. Mandibular Major Connectors 1- Lingual bar :- Half-pear shaped with bulkiest portion inferiorly located. The superior border of a lingual bar connector should be tapered toward the gingival tissue superiorly with its greatest bulk at the inferior border. The superior border should be at located 3-4mm away from the gingival margin & more if possible to prevent blood constriction. 2-Linguoplate :- Half-pear shaped , thin ,follow the contours of the teeth and the embrasures. Thin metal extending superiorly to contact cingula. Apron extended interproximally to the height of contact points (closing interproximal spaces) 3-Lingual bar with continuous bar indirect retainer Thin, narrow (3mm) metal strap located on cingula of anterior teeth, scalloped to follow interproximal embrasures with inferior and superior borders tapered to tooth surfaces. Lower part, Conventionally shaped and located same as lingual bar major connector. Advantages: More rigid than lingual bar. Covers less tooth & tissue surface than lingual plate. Disadvantages: Very complex design May be objectionable to patient because there are four edges exposed to the tip of the tongue. Potential food traps between two bars. 4 - Cingulum Bar (Continuous Bar) Thin, narrow (3 mm) metal bar located on cingula of anterior teeth, scalloped to follow interproximal embrasures with inferior and superior borders tapered to tooth surfaces 5- Labial bar :- Half-pear shaped with bulkiest portion inferiorly located on the labial and buccal aspects of the mandible. Superior border tapered to soft tissue.located at least 4 mm inferior to labial and buccal gingival margins and more if possible. Indications: lingual inclinations of remaining mandibular premolar and incisor teeth cannot be corrected. severe lingual tori cannot be removed and prevent the use of a lingual bar or lingual plate major connector. severe and abrupt lingual tissue undercuts