2Major ConnectorA major connector is the component of the RPD that connects the parts of the prosthesis located on one side of the arch with those on the opposite side.It is that unit of the RPD to which all other parts are directly or indirectly attached.
3Functions of Major Connector UnificationPartial denture acts as one unitConnects various parts
4Functions of Major Connector Stress DistributionDistributes functional loads to both teeth & mucosa
5Functions of Major Connector Cross-Arch Stabilization * (Counterleverage)Bracing elements on one side of the arch providing stability to the otherCross -arch stabilization: resistance against dislodging or rotational forces obtained by using a partial removable dental prosthesis design that uses natural teeth on the opposite side of the dental arch from the edentulous space to assist in stabilization.
6Requirements of Major Connector Rigidity *Functions as one unitTo distribute forces effectively over the entire supporting structures.To resist flexing and torque that could be transmitted to the abutments and other structures as destructive forces
7To Increase Rigidity Use a more rigid alloy Shape (cross-section) Chrome-cobalt > gold alloys; cast > wroughtShape (cross-section)1/2 round > 1/2 pear shaped > flat bars
8To Increase Rigidity Increase the bulk as the length increases Corrugate linguoplate or rugae areas
9Requirements Non-Interference with soft tissues Should not enter undercut areasavoid by changing path of insertionor by using blockout
10Non-Interference With Tissues Avoid terminating on:Free gingival marginCross abruptly at 90oRelief is used to minimize impingement
11Borders of maxillary connector should be placed a minimum of 6 mm away from and parallel to the gingival margins. Border of mandibular connector should be located a minimum of 4 mm below the gingival margin
12Non-Interference With Tissues Avoid terminating on:Hard structures such as the mid-palatal suture or mandibular toriPlace relief
13Non-Interference With Tissues Avoid terminating on:Lingual frenum & the movable soft palateSoft tissue movements must also be allowed
14Minimize Food Impaction Locate margins away from the FGMEliminate "traps" or large concavities where food can collect
15Unobtrusive *Smooth transition from connector to denture base - butt jointnot noticeable or conspicuous
16Unobtrusive Line angles and edges should be smooth and rounded Borders should not interfere with speech
17ReliefMandibular major connectors should be located and/or relieved to prevent impingement of tissue because the distal extension denture rotates in function.Except for a palatal torus or prominent median palatal suture area, maxillary connectors ordinarily require no relief.
18Mandibular Major Connectors Lingual BarLingual PlateSublingual barLingual bar with cingulum bar (continuous bar)Labial barSwing lock design
19Mandibular Major Connectors Lingual BarMost common in mandibeUse whenever possible
20Mandibular Major Connectors Lingual BarShapeFlat on tissue sideConvex or tear-drop on tongue side(1/2 pear shape, with thin edge toward teeth)
21Lingual BarLocated above moving tissue but as far below the gingival tissue as possibleThe superior border should be tapered toward the gingival tissue superiorly with its greatest bulk at the inferior border, resulting in a contour that is a half-pear shape.
22Mandibular Major Connectors Lingual BarSizeOccluso-gingival width = 4 to 6 mmThickness = l.5 to 2 mm
23Inferior Border of Lingual Bar * Patient lifts tongueActivates floor of mouthMeasure from tip of probe to free gingival marginORMake impressionwith lifted tongueMeasure on castLocate the inferior border as far inferiorly as possible to avoid interference with the resting tongue and trapping of food; without exceeding the functional depth of lingual vestibule.
25Lingual Bar Position Superior border 3-4 mm or more below FGM As far from gingival margin as possible
26Mandibular Major Connector Relief Eliminates impingementWax spacer (relief) placed under major connectorOne thickness of 30 gauge wax *0.010“ inch or 0.25 mm thickness
27Lingual Bar Indication The lingual bar should be used for mandibular RPD where sufficient space exists between the slightly elevated alveolar lingual sulcus and the lingual gingival tissue (more than 8 mm)
28Contraindications for Lingual Bar Remaining natural anterior teeth severely tilted linguallyInterfering lingual toriHigh attachment of lingual frenumInterference with elevation of the floor of the mouth during functional movements (< 8 mm)
29Lingual Plate (Linguoplate) Lingual bar with extension over cingula of anterior teethUse where a lingual bar cannot be used
30Lingual PlateInferior border at the ascertained height of the alveolar lingual sulcus when the patient's tongue is slightly elevated.
31Lingual Plate Rest at each end of lingual plate Prevents forces being directed faciallyEasier denture tooth addition than bar *Linguoplate is indicated when the future replacement of one or more incisor teeth will be facilitated by the addition of retention loops to an existing linguoplate
32Lingual Plate Variations May show through embrasures
33Lingual Plate Indications Potential Impingement from lingual barHigh floor of the mouth (< 8 mm)Prominent lingual frenumLingual tori
34Lingual Plate Indications The residual ridges in Class I arch have undergone such vertical resorption that they will offer only minimal resistance to horizontal rotations of the denture through its bases.For using periodontally weakenedteeth to furnish support to prosthesis and to help resist horizontal rotation of the distal extension type of denture. (act as periodontal splint)
35Lingual bar with secondary bar on cingula of anterior teeth * Mandibular Lingual Bar with Continuous Bar (Cingulum Bar) (Kennedy Bar, Double Lingual Bar)Lingual bar with secondary bar on cingula of anterior teeth *Originates bilaterally from incisal, lingual, or occlusal rests of adjacent principal abutments.
36Mandibulat Lingual Bar with Continuous Bar Indications When a linguoplate is otherwise indicated but the axial alignment of anterior teeth is such that excessive blockout of interproximal undercuts would be required.When wide diastema exists between mandibular anterior teeth and a linguoplate would objectionably display metal in a frontal view.
37Mandibulat Lingual Bar with Continuous Bar Potential food trap between two barsNormally avoid
38Labial Bar Extreme lingual inclination of the remaining teeth * Indications are rareSwing-lock design (Hinged Continuous Labial Bar) is a variationOr When severe lingual tori cannot be removed and prevent the use of a lingual bar or lingual plate major connector
39Maxillary Major Connectors Anterior-Posterior Palatal StrapPalatal plate-type connectorSingle palatal strapU-shaped palatal connector (Anterior Palatal Strap)Single palatal barAnterior-posterior palatal bar
40Maxillary Major Connectors Whenever it is necessary for the palatal connector to make contact with the teeth for support, definite tooth support by definite rest seats should be provided *Because major connector components resting on unprepared inclined tooth surfaces can lead to slippage of the denture or to orthodontic movement of the tooth, or to both.
41Maxillary Major Connectors Terminate 6.0 mm or more from free gingival margin when possible
42Anterior-Posterior Palatal Strap* Maximum rigidityMinimum bulkUse in most casesEspecially torus palatinusRelatively narrow (8 to 10 mm) anterior and posterior palatal straps. Lateral palatal straps (7 to 9 mm) broad and parallel to curve of arch.Anterior border of this strap should be located just posterior to a rugae crest or in the valley between two crests.
43Anterior-Posterior Palatal Strap Indications Class I and II arches in which excellent abutment and residual ridge support exists, and direct retention can be made adequate without the need for indirect retention.Long edentulous spans in Class II, modification 1 arches.Class IV arches
44Anterior-Posterior Palatal Strap Indications Inoperable palatal tori that do not extend posteriorly to the junction of the hard and soft palates.The only condition preventing its use is when there is an inoperable maxillary torus that extends posteriorly to the soft palate.
45Anterior-Posterior Palatal Bar A narrow (A-P) variation of anterior-posterior palatal strapDouble palatal bar connectorRequires greater bulk for rigidity
46Anterior-Posterior Palatal Bar More objectionable to the patientStrap connectors provide greater distribution of stresses
47Palatal Plate-Type Connector Covers one half or more of the hard palateMaximum tissue supportConnector of choice in long distal extension cases
48Palatal Plate-Type Connector Greater stability and stress distributionNot used with torusIncreases retention
49Palatal Plate-Type Connector Connector should:be fabricated of uniformly thin metal *have accurate anatomic reproduction of the rugaeimproves strength and rigidityThermal conductivity makes it more acceptable for the tongue and the underlining tissues
50Palatal Plate-Type Connector Connector should:Cover same area as complete denture posteriorlyHave large surface area of mucosal contactimproves potential for retention
51Palatal Plate-Type Connector Forms A cast plate between two or more edentulous areasA complete or partial cast plate that extends posteriorly to the junction of the hard and soft palate
52Palatal Plate-Type Connector Forms 3. An anterior palatal connector with a provision for extending an acrylic resin denture base posteriorly
53Palatal Plate-Type Connector Indications Abutments are periodontally involvedMaximum stress distribution is needed*Flabby tissueShallow palatal vault1. Class I arch with one to four premolars and some or all anterior teeth remaining, and abutment support is poor and cannot otherwise be enhanced; residual ridges have undergone extreme vertical resorption; direct retention is difficult to obtain.2. Class II arch with a large posterior modification space and some missing anterior teeth.3. Six or less anterior teeth remain
54Single Palatal Strap Usually use for Class III & IV cases * Bilateral edentulous spaces of short span in a tooth-supported restoration, particularly when the edentulous areas are located posteriorly.Should not be used to connect anterior replacements with distal extension bases
55Single Palatal StrapStrap should be 8mm wide or approximately as wide as the combined width of a maxillary premolar and first molar.Confined within an area bounded by the four principal rests
56Single Palatal StrapNever use in cases involving distal extensions since it must be made bulky for rigidityRelief may be required over bony midlineNot used with torus
57Palatal Bar Don’t use Narrow anterio-posteriorly Thick occluso-gingivallyPalatal bar objectionable due to bulkLess than 8 mm in width, thin, flexible
58U-Shaped or "Horse-Shoe" Palatal Connector Poor connectorNever use unless absolutely necessaryRequires bulk in the rugae area (where the tongue requires freedom) for rigidity
59U-Shaped or "Horse-Shoe" Palatal Connector Too flexibleAllows movement at the posteriorTraumatic to the residual ridgeUse only where torus prohibits other connector & extends to the posterior limit of the hard palate