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Major Connectors. Functions of a Major Connector  Unification  Partial denture acts as one unit  Connects various parts  Unification  Partial denture.

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Presentation on theme: "Major Connectors. Functions of a Major Connector  Unification  Partial denture acts as one unit  Connects various parts  Unification  Partial denture."— Presentation transcript:

1 Major Connectors

2 Functions of a Major Connector  Unification  Partial denture acts as one unit  Connects various parts  Unification  Partial denture acts as one unit  Connects various parts

3 Functions of a Major Connector  Stress Distribution  Distributes functional loads to both teeth & mucosa  Stress Distribution  Distributes functional loads to both teeth & mucosa

4 Functions of a Major Connector  Cross-Arch Stabilization (Counterleverage)  Bracing elements on one side of the arch providing stability to the other  Cross-Arch Stabilization (Counterleverage)  Bracing elements on one side of the arch providing stability to the other

5 Requirements of a Major Connector  Rigidity  Functions as one unit  Rigidity  Functions as one unit

6 To Increase Rigidity  Use a more rigid alloy  Chrome-cobalt > gold alloys; cast > wrought  Shape  1/2 round > 1/2 pear shaped > flat bars  Use a more rigid alloy  Chrome-cobalt > gold alloys; cast > wrought  Shape  1/2 round > 1/2 pear shaped > flat bars

7 To Increase Rigidity  Increase the bulk as the length increases  Corrugate linguo-plate or rugae areas  Increase the bulk as the length increases  Corrugate linguo-plate or rugae areas

8 RequirementsRequirements  Non-Interference with Tissues  Should not enter undercut areas  avoid by changing path of insertion  or by using blockout  Non-Interference with Tissues  Should not enter undercut areas  avoid by changing path of insertion  or by using blockout

9 Non-Interference With Tissues  Avoid terminating on:  Free gingival margin  Cross abruptly at 90 o  Relief is used to minimize impingement  Avoid terminating on:  Free gingival margin  Cross abruptly at 90 o  Relief is used to minimize impingement (Fig 2-17, Stewart's)

10 Non-Interference With Tissues  Avoid terminating on:  Hard structures such as the mid- palatal suture or mandibular tori  Place relief  Avoid terminating on:  Hard structures such as the mid- palatal suture or mandibular tori  Place relief

11 Non-Interference With Tissues  Avoid terminating on:  Lingual frenum & the movable soft palate  Soft tissue movements must also be allowed  Careful intraoral exam  Avoid terminating on:  Lingual frenum & the movable soft palate  Soft tissue movements must also be allowed  Careful intraoral exam

12 Minimize Food Impaction  Locate margins away from the FGM  Eliminate "traps" or large concavities where food can collect  Locate margins away from the FGM  Eliminate "traps" or large concavities where food can collect

13 UnobtrusiveUnobtrusive  Smooth transition from connector to denture base - butt joint

14 UnobtrusiveUnobtrusive  Line angles and edges should be smooth and rounded  Borders should not interfere with speech  Line angles and edges should be smooth and rounded  Borders should not interfere with speech (Fig 2-21, Stewart's)

15 Mandibular Major Connectors  Lingual Bar  Lingual Plate  Continuous Bar  Lingual Bar  Lingual Plate  Continuous Bar

16 Mandibular Major Connectors  Lingual Bar  Most common in mandibe  Use whenever possible  Lingual Bar  Most common in mandibe  Use whenever possible

17 Lingual Bar  Reasons for choosing  Most hygienic (least tooth contact)  Most comfortable (least coverage)  Reasons for choosing  Most hygienic (least tooth contact)  Most comfortable (least coverage)

18 Mandibular Major Connectors  Lingual Bar  Shape  Flat on tissue side  Convex or tear-drop on tongue side  (1/2 pear shape, with thin edge toward teeth)  Lingual Bar  Shape  Flat on tissue side  Convex or tear-drop on tongue side  (1/2 pear shape, with thin edge toward teeth) (Fig 2-35, Stewart's)

19 Mandibular Major Connectors  Lingual Bar  Size  Occluso-gingival width = 4 to 6 mm  Thickness = 2 to 3 mm  Lingual Bar  Size  Occluso-gingival width = 4 to 6 mm  Thickness = 2 to 3 mm

20 Inferior Border Mandible  Patient lifts tongue  Activates floor of mouth  Measure from tip of probe to free gingival margin  Patient lifts tongue  Activates floor of mouth  Measure from tip of probe to free gingival margin

21 Inferior Border Mandible  Record values in chart, transfer to cast

22 Lingual Bar  Position  Superior border  Prefer at least l mm or more below FGM; absolute min: 1.0 mm  As far from gingival margin as possible  Position  Superior border  Prefer at least l mm or more below FGM; absolute min: 1.0 mm  As far from gingival margin as possible (Fig 2-15, Stewart's)

23 Potential Impingement  Anterior major connector moves toward tissue as the posterior portion is loaded  More space needed when ridge is more horizontal  Anterior major connector moves toward tissue as the posterior portion is loaded  More space needed when ridge is more horizontal (Fig 2-33, Stewart's)

24 Mandibular Major Connector Relief  Eliminates impingement  Wax spacer (relief) placed under major connector  one thickness of 30 gauge wax  Eliminates impingement  Wax spacer (relief) placed under major connector  one thickness of 30 gauge wax

25 Lingual Plate (Linguoplate)  Lingual bar with extension over cingula of anterior teeth  Use where a lingual bar cannot be used  Lingual bar with extension over cingula of anterior teeth  Use where a lingual bar cannot be used

26 Lingual Plate Indications  Potential Impingement from lingual bar  High floor of the mouth  Prominent lingual frenum  Lingual tori  Stabilize mobile teeth (not always needed)  Need to add denture teeth if anterior teeth will be subsequently lost  Potential Impingement from lingual bar  High floor of the mouth  Prominent lingual frenum  Lingual tori  Stabilize mobile teeth (not always needed)  Need to add denture teeth if anterior teeth will be subsequently lost

27 Lingual Plate  Rest at each end of lingual plate  Prevents forces being directed facially  Easier denture tooth addition than bar  Rest at each end of lingual plate  Prevents forces being directed facially  Easier denture tooth addition than bar

28 Lingual Plate Variations  May show through embrasures (Fig 2-41 & 43, Stewart's)

29 Continuous Bar Retainer (Kennedy Bar, Double Lingual Bar)  Lingual bar with secondary bar above cingula  Secondary bar acts as indirect retainer  Lingual bar with secondary bar above cingula  Secondary bar acts as indirect retainer

30 Continuous Bar Retainer  Potential food trap between two bars  Normally avoid  Potential food trap between two bars  Normally avoid

31 Labial Bar  Extreme lingual inclination of the remaining teeth  Indications are rare  Swing-lock design is a variation  Extreme lingual inclination of the remaining teeth  Indications are rare  Swing-lock design is a variation

32 Maxillary Major Connectors  Anterior-Posterior Palatal Strap  Full Palatal Strap  Palatal Strap  Anterior Palatal Strap  Anterior-Posterior Palatal Strap  Full Palatal Strap  Palatal Strap  Anterior Palatal Strap

33 Maxillary Major Connectors  Terminate 4.0 mm or more from free gingival margin when possible

34 Anterior-Posterior Palatal Strap  Maximum rigidity, Minimum bulk  Comfort (minimum coverage)  Use in most cases  Especially torus palatinus  Maximum rigidity, Minimum bulk  Comfort (minimum coverage)  Use in most cases  Especially torus palatinus

35 Anterior-Posterior Palatal Bar  Variation of anterior-posterior palatal strap  Double palatal bar connector  Requires greater bulk for rigidity  More objectionable to the patient  Variation of anterior-posterior palatal strap  Double palatal bar connector  Requires greater bulk for rigidity  More objectionable to the patient

36 Full Palatal Plate  Maximum tissue support  Connector of choice in long distal extension cases  Six or less anterior teeth remain  Maximum tissue support  Connector of choice in long distal extension cases  Six or less anterior teeth remain

37 Full Palatal Plate  Abutments are periodontally involved  Maximum stress distribution  Flabby/compressible support  Abutments are periodontally involved  Maximum stress distribution  Flabby/compressible support

38 Full Palatal Plate  Greater stability and stress distribution  Not used with torus  Increases retention  Greater stability and stress distribution  Not used with torus  Increases retention

39 Full Palatal Plate  Connector should:  Be fabricated of uniformly thin metal  Have accurate anatomic reproduction of the ruggae  improves strength and rigidity  Connector should:  Be fabricated of uniformly thin metal  Have accurate anatomic reproduction of the ruggae  improves strength and rigidity

40 Full Palatal Plate  Connector should:  Cover same area as complete denture posteriorly (point to hamular notch if distal extension)  Have large surface area of mucosal contact  improves potential for retention  Connector should:  Cover same area as complete denture posteriorly (point to hamular notch if distal extension)  Have large surface area of mucosal contact  improves potential for retention

41 Full Palatal Plate  Generally of cast metal  Acrylic resin used in interim prostheses  Generally of cast metal  Acrylic resin used in interim prostheses

42 Palatal Strap  Usually use for Class III & IV cases  Wide anterio-posteriorly  Usually use for Class III & IV cases  Wide anterio-posteriorly

43 Palatal Bar  Don ’ t use  Narrow anterio-posteriorly  Thick occluso-gingivally  Palatal bar objectionable due to bulk  Don ’ t use  Narrow anterio-posteriorly  Thick occluso-gingivally  Palatal bar objectionable due to bulk (Fig 2-24, Stewart's)

44 Palatal Strap (or Bar)  Never use in cases involving distal extensions or replacement of anterior teeth since it must be made bulky for rigidity  Relief may be required over bony midline  Not used with torus  Never use in cases involving distal extensions or replacement of anterior teeth since it must be made bulky for rigidity  Relief may be required over bony midline  Not used with torus

45 Anterior Palatal Plate (U-Shaped or "Horse-Shoe" Palatal Connector)  Poor connector  Never use unless absolutely necessary  Requires bulk in the rugae area (where the tongue requires freedom) for rigidity  Poor connector  Never use unless absolutely necessary  Requires bulk in the rugae area (where the tongue requires freedom) for rigidity

46 Anterior Palatal Plate  Too flexible  Allows movement at the posterior  Traumatic to the residual ridge  Use only where torus prohibits other connectors  Too flexible  Allows movement at the posterior  Traumatic to the residual ridge  Use only where torus prohibits other connectors

47 Flexes, impinging on soft tissue

48 Unilateral RPD  Dangerous  Avoid  aspiration  Dangerous  Avoid  aspiration

49 Next:Next:   Retentive Undercut Abutment Modifications Presentation  Videos:  Double embrasure movie  Retentive undercuts   Retentive Undercut Abutment Modifications Presentation  Videos:  Double embrasure movie  Retentive undercuts


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