Presentation is loading. Please wait.

Presentation is loading. Please wait.

Fabricating Removable Partial Denture Bases. (1) Factors Affecting Selection of Artificial Teeth (2) Altered Cast Technique (3) Procedures for Articulating.

Similar presentations


Presentation on theme: "Fabricating Removable Partial Denture Bases. (1) Factors Affecting Selection of Artificial Teeth (2) Altered Cast Technique (3) Procedures for Articulating."— Presentation transcript:

1 Fabricating Removable Partial Denture Bases

2 (1) Factors Affecting Selection of Artificial Teeth (2) Altered Cast Technique (3) Procedures for Articulating and Restoring VDO (4) Procedures for Arranging Artificial Teeth and Waxing Up Denture Bases

3 (1)Factors Affecting Selection of Artificial Teeth (a)Criteria for common denture base and artificial tooth combinations 1Maxillomandibular space 2Esthetic values 3Absence of soft tissue undercuts 4Length of edentulous space 5Health of soft tissue and anticipated rate of bone resorption

4 (1)Factors Affecting Selection of Artificial Teeth 4 The choice of selecting acrylic or porcelain teeth are determined by the dentist

5 (b)Types of anterior tooth and tissue replacement 4 (Primary factor is esthetic acceptability) 1Commercial facings aPrefabricated facings retained on a metal backing with a cementing medium bIdentical replacement possible cMay be used when undesirable soft tissue undercuts are present dNo reline potential

6 (b)Types of anterior tooth and tissue replacement 2Reinforced Acrylic Pontics aDenture teeth ground to fit an edentulous space and retained on a metal base bVariety of shades and molds cAn advantage over commercial facings are the improved three dimensional effects, such as overlapping teeth dMay be used when undesirable soft tissue undercuts are present

7

8

9 Braided Post Used with stock denture teeth similar to RAP. Denture teeth not needed for wax-up

10 (b)Types of anterior tooth and tissue replacement 3Processed tooth-colored resin aWaxed to metal framework and processed with tooth- colored resin bMay be used when undesirable soft tissue undercuts are present cRequires stable ridge

11 (b)Types of anterior tooth and tissue replacement 4Acrylic denture teeth with resin base aAttached to metal retention grid or mesh bCompensates for gross ridge resorption cResin base provides support and bracing dResin can be relined eRequires significant vertical space f Not recommended when deep labial soft tissue undercuts are present

12 (c)Types of posterior tooth and tissue replacement 1Acrylic denture teeth with denture resin aAttached to metal retention grid or mesh bDenture base can be relined cEasy to modify dModerately esthetic

13 (c)Types of posterior tooth and tissue replacement 2Metal teeth integrated into framework aBetter tissue adaptation than processed acrylic bRequires least amount of space cLeast esthetic 3Tube tooth attached to metal denture base aLimited to short span, well healed areas bRequires 4 mm posts for adequate retention

14

15 (c)Types of posterior tooth and tissue replacement 4Processed tooth-colored resins with spiral post retention aShort span application bSubstitute for tube teeth cRequires slightly less interarch space than a tube tooth

16

17 (2)Altered Cast Technique (a)Definition - A corrected impression of the distal extension area(s) of the patient’s mouth, made after the fit of the framework is confirmed in the mouth and before artificial teeth are arranged (b)Purpose - This procedure is designed to ensure the best possible soft tissue support for a distal extension denture base

18 (c)Procedures for the Altered Cast Technique 1Dentist adjusts and fits the framework in the patient’s mouth 2Dentist designs outline of proposed impression tray 3Plastic tray will be constructed over the framework’s distal denture base retention 4Adapt a 26 gauge sheet wax spacer to the edentulous area, then adapt a second layer of 26 gauge sheet wax to the retromolar pad and blend it with the first sheet wax layer, trim wax to design line

19

20 (c)Procedures for the Altered Cast Technique 5Warm the distal extension grid of the framework over a flame and place the framework on the master cast aBe sure the rests are fully seated bRemove any wax that flowed over the metal capply separator to cast 6Mix self curing resin to a dough-like consistency 7Adapt resin over the edentulous area to form a tray that is firmly attached to the retention grid

21

22 (c)Procedures for the Altered Cast Technique 8After resin is cured, lift the framework with attached tray from the cast 9Trim the tray to the outline the spacer forms 10Remove wax spacer 11Disinfect IAW manufacturer’s directions 12Return framework to the dentist

23 (c)Procedures for the Altered Cast Technique 13Making the corrected impression aThe dentist makes the corrected impression bImpression material is placed in the tray(s), then the entire framework is seated in the patient’s mouth cDisinfect the completed impression

24 (c)Procedures for the Altered Cast Technique 14Altering the Master Cast aDraw design for saw cuts across the distal extension, from buccal to lingual, on a line that passes 1 mm behind the distal abutment bDraw another saw cut line that is parallel and lingual to the lingual sulcus to join with the first cut cCut along design lines dUsing a fissure bur or a saw, place multiple dovetail cuts in the cut surface of the cast to create mechanical retention for the corrected addition

25

26 (c)Procedures for the Altered Cast Technique ePlace the framework with corrected impression on the prepared master cast 1Be certain all rests are in complete contact with their respective seats 2Secure the framework in place with sticky wax

27 (c)Procedures for the Altered Cast Technique fBead and box around the borders of the impression 1Place utility wax around the outer border of the impression 3 mm below the peripheral roll and seal it to both the impression and the base of the cast at the ends of the wax 2Seal boxing wax in place even with the height of the base of the cast and along the outer border of the utility wax gSoak the base of the cast for about 5 minutes

28

29 (c)Procedures for the Altered Cast Technique hVacuum mix stone and pour impression 1Use manufacturer’s directions for water/powder ratio 2Remove wax after stone sets iSeparate Cast 1Remove framework and tray from the cast 2Completely clean debris from the cast 3Check the cast for voids 4Trim cast, preserving the land area

30

31 (c)Procedures for the Altered Cast Technique jRemove acrylic resin tray 1Flame tray until it softens 2Peel tray from the framework 3Clean framework thoroughly kSeat the framework back on the cast with all rests seated

32 1. Procedures for Arranging Artificial Teeth and Waxing Up Denture Bases a. Tooth arrangement 1. If try-in is going to be accomplished, tinfoil is applied to cast over edentulous area as separator 2. Set the maxillary posterior teeth a. Flow wax around denture base retention to seal frame to cast b. Lower incisal guide pin 0.5 mm c. Set posterior teeth in maximum intercuspation 1. Marginal ridges set at same height 2. Maintain buccal alignment with adjacent teeth 3. Eccentric contacts must be avoided

33 1. Procedures for Arranging Artificial Teeth and Waxing Up Denture Bases a. Tooth arrangement 1. If try-in is going to be accomplished, tinfoil is applied to cast over edentulous area as separator 2. Set the maxillary posterior teeth a. Flow wax around denture base retention to seal frame to cast b. Lower incisal guide pin 0.5 mm c. Set posterior teeth in maximum intercuspation 1. Marginal ridges set at same height 2. Maintain buccal alignment with adjacent teeth 3. Eccentric contacts must be avoided

34

35

36 1. Procedures for Arranging Artificial Teeth and Waxing Up Denture Bases a. Tooth arrangement d. Return incisal guide pin flush with upper member e. Grind occlusal surfaces until pin touches the table to develop tight maximum intercuspation

37 1. Procedures for Arranging Artificial Teeth and Waxing Up Denture Bases b. Wax-up 1. Snowshoe principle a. Establish full coverage; cover ridge, mucco-buccal and lingual folds entirely b. Pressure is distributed over a broad surface area rather than concentrated on a point 2. Bulk wax - from finish lines to 1 mm past blue design line a. Overwax 2 mm onto the external finish line; allows finishing with no step between metal and acrylic b. Fill peripheral roll

38 b. Wax-up 3. Gingival trim - duplicate natural tissue a. 45  angle on the buccal side b. 90  angle on the lingual side 4. Festooning - eminences, when contoured should appear natural 5. Check occlusion to ensure no tooth movement has occurred during waxing

39

40 (3)Finishing RPD Bases (b)Remount the casts on the articulator (c)Selective Grind Artificial teeth

41 (3)Finishing RPD Bases (c)Restore vertical dimension of occlusion 1Ensure incisal pin contacts the incisal guide table 2Be sure to maintain contacts in tight centric occlusion 3Adjust Excentric excursions, Protrusive and lateral

42 (3)Finishing RPD Bases (d)Carefully remove RPDs from casts (don’t break acrylic or bend out clasps) (e)Finish 1Trim flash using arbor bands or acrylic trimming stone 2Free acrylic from clasp using sandpaper discs 3Smooth transition between acrylic and external finish lines using rubber points and wheels 4Borders should be round with no sharp edges

43 (3)Finishing RPD Bases 5Use a fissure bur to grind bubbles from gingival trim (f)Polish 1Do not pumice festooning away - go back to finishing for hard to get areas 2Close attention should be given around clasps 3Repolish metal areas as necessary (g)Disinfect RPDs IAW manufacturer's directions

44 Denture Base Repairs 4 Denture Tooth Repair –Box Preparation –Matrix to position tooth

45 Denture Base Repairs 4 Denture Base Fracture –Rabbet Preparation –Position on cast

46 Denture Base Repairs 4 Denture Base Reline –Reline Jig


Download ppt "Fabricating Removable Partial Denture Bases. (1) Factors Affecting Selection of Artificial Teeth (2) Altered Cast Technique (3) Procedures for Articulating."

Similar presentations


Ads by Google