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Comp. Remov. Prosthodontics Burleson Objectives Lecture 1 : The Edentulous Problem 1.

support - resistance to vertical movement of the denture base towards the ridge stability - resistance to horizontal or rotational movements retention - resistance to displacement of the denture base away from the ridge adhesion - of dentures to the saliva cohesion- of saliva to itself interfacial surface tension - thin fluid film between two closely contacting objects border seal - prevents an ingress of air

2.

Maxillary complete denture - primary support area is the hard palate; secondary support is the residual ridge

3.

Mandibular complete denture - primary support area is buccal shelf; secondary support is residual ridge

4.

stability - determined by ridge height, base adaptation, occlusal harmony, neuromuscular control

5.

retention - promoted by adhesion, cohesion, interfacial surface tension a) maximal extension of the denture base b) maximum intimate contact

6.

centric relation - the most posterior position of the mandible relative to the maxillae at the established vertical dimension; CR coincides with a reproducable posterior hinge position of the mandible

7.

centric occlusion - position of maximum planned intercuspation of teeth - in edentulous patients the CR position is set equal to centric occlusion - centric occlusion cannot be measured in edentulous pts. since it is a tooth-defined position

8.

mean denture-bearing areas: a) maxilla = 22.96cm2 b) mandible = 12.25cm2 c) PDL available in each dental arch = 45cm2

9.

residual ridge resorption is a serious problem in denture wearers - mean reduction in anterior position of mandibular process is four times that of the maxilla - average mandibular reduction over 25 years = 10mm while maxilla is 3mm of resorption

10.

saliva - good saliva is needed for adequate retention - SjÜgren’s syndrome, radiation, medications all cause xerostomia - salivary flow also decreases with age

11.

snowshoe principle - decrease the pressure per unit area of ridge and supporting structures - by extending the denture base to cover maximum area within physiologic tolerance (support)

1


Comp. Remov. Prosthodontics Burleson Lecture 2: Preliminary Impressions / Casts 1.

Making preliminary casts: - satisfactory preliminary impressions are necessary for satisfactory custom trays - preliminary impressions are needed to fabricate diagnostic casts Diagnostic casts: - give 3-dimensional record of patient’s existing foundation for the dentures - good visual aid for treatment plan presentation to patient - custom tray fabrication - evaluation of the need for preprosthetic surgery

2.

Two materials most commonly used for preliminary impressions: a) impression compound - thermoplastic b) irreversible hydrocolloid - aliginate impression

3.

Method of tray selection: - need 3-5mm of alginate thickness between tray and tissue - maxillary tray must cover both hamular notches and the vibrating line - mandibular tray must cover the retromolar pads Modifying a stock tray: tray may be altered by adding periphery wax or modeling compound

4.

Technique for making preliminary alginate impression: a) mark vibrating line with Thompson’s marker b) insert tray and visually inspect c) alginate adhesive used for non-perforated trays d) mix aliginate in room-temp. water for 45sec e) load tray and place additional material into palate (rugae) area or vestibules f) seat tray and hold very still using light pressure; sets 3 minutes g) remove with firm quick snap h) inspect, disinfect, wrap in wet towel and pour impression within 15 minutes * alginate impressions imbibe or lose water which creates distortion

5.

Maxillary impressions should include: a) hamular notches and residual ridges b) fovea palatini and entire hard palate c) entire buccal vestibule d) right, left, and labial frenal attachments e) mucolabial reflection area Mandibular impressions should include: a) retromolar pads b) external oblique ridges and buccal shelf area c) right, left, and labial frenal attachments d) lingual frenum and sublingual space e) retromylohyoid spaces f) mucolabial reflection area

6.

Technique for pouring and trimming preliminary casts - vibrate vacuum-mixed dental stone into impression; initial set at 10 minutes - mix stone and form a base and insert impression into base; allow to stand for 1 hour and separate - dampen cast and trip base parallel to alveolar ridges - thickness of cast should be 12-14mm or 1/2 inch thick at thinnest area - give land area of 3-4mm wide and posterior areas 6mm behind hamular notches/retromolar pad areas

7.

Making a VLC custom tray - (visible light cured = autopolymerization); 2-3mm thick around denture base - stop short of mucolabial reflection areas; handle doesn’t interfere with lip or pressure

2


Comp. Remov. Prosthodontics Burleson Lecture 3 : Border Molding and Secondary Impressions 1.

Three philosophies of impression making in complete dentures a) minimal pressure - uses accurate free-flowing impression material to capture tissue in undisplaced state - not so concerned about maximum extension of denture borders b) functional pressure - impression material and tray are less displacable than the tissue - muscle actions are done while the material sets - soft tissues are displaced - may unseat denture when they rebound c) selective pressure impression - dentist decides which tissues get more pressure and which get less - uses pt. anatomy and tissue tone to achieve stability, retention, and patient comfort - custom tray offers the means by which the dentist can control the amount and location of tissue pressure

2.

Purposes of border molding - determines the extension of the denture - duplicates the contour and size of the vestibule - ensures a peripheral seal in the completed denture

3.

Maxillary border molding technique: a) retrozygomatic area - manipulate cheek outward and downward; pt. close firmly; move mandible b) buccal flange - move cheeks downward and inward c) buccal frenum - massage cheek downward and inward; lightly anterior-posterior d) labial flange - pt. suck on finger or gently extend lip outward and downward e) labial frenum - extend lip outward and downward f) posterior palatal seal - pt. open wide; pinch nose and try to blow; swallow * posterior region must always include the vibrating line Mandibular border molding technique: a) alveolingual sulcus / lingual frenum - pt. wet upper and lower lips with tongue; push tongue against palate b) mylohyoid area - pt. swallow forcefully several times; move tongue into buccal vestibules c) retromylohyoid area - push tongue against tray handle and bite down d) masseteric notch - close down on fingers and open mouth wide e) buccal flange - move cheek out, up, and in f) buccal frenum - elevate cheek slightly massaging upward and anterior-posterior g) labial flange- manipulate lip slightly upward h) labial frenum - elevate frenum area and lightly massage the lip vertically

4.

Imperfections which cause remaking of the secondary impression a) thick buccal border on one side with a thin buccal border on the opposite side = tray out of position b) thin labial border = tray too far posteriorly c) thick lingual border on one side with thin lingual border on other side = lower tray out of position d) thin anterior lingual border = tray too far anterior e) excess thickness of impression over tray = not seated fully f) tray showing through impression = tray seated too far

3


Comp. Remov. Prosthodontics Burleson Lecture 4 : Record Bases and Jaw Relation Records 1. Purpose of posterior palatal seal: a) retention and stability achieved from adhesion, cohesion, and interfacial surface tension b) adequate border seal resists horizontal forces c) allows mucosa to move with the denture base during function and maintain the seal 2.

Methods of Placing the posterior palatal seal: a) fluid wax technique - waxes are added which flow at mouth temperature - add to secondary impression b) arbitrary scraping - of the master cast

3.

Relevance & Rationale for posterior palatal seal: a) primary purpose is retention of the maxillary denture b) reduces patient awareness of the area c) reduces food accumulation at posterior aspect of the denture d) compensates for volumetric shrinkage that occurs during polymerization of denture base resin e) creates a partial vacuum and maintains the denture seal f) place in the record base to keep them more retentive, psychologically secure the pt., and confirm location

4.

Purposes of Record Bases: a) establish occlusal vertical dimension b) establish resting vertical dimension c) establish and evaluate interocclusal distance d) determine and record centric relation and maxillomandibular relations e) transfer accurate jaw relations to the articulator f) enable setting teeth and waxing contours for wax try-in

5.

Requirements of acceptable record bases: a) stability both on cast and intraorally b) rigidity c) comfort for patient in order to achieve successful records d) accurate adaptation to cast with full coverage to vestibular depth and adequate anatomical coverage

6.

Purposes of Occlusion Rims a) serve as a blueprint for where the teeth will go; may use waxes or modeling compound b) aid in determining length and width of artificial teeth c) provide proper lip support d) locate the midline of arch and cuspid eminences

7.

Initial Dimensions of wax occlusal rims a) maxillary - anterior incline labially, 22mm vertical height anteriorly, and 5-7mm high & 8-10mm wide post. b) mandibular - labial inclination, 18mm vertical height anteriorly, 1/2 to 2/3 up retromolar pad & 8-10mm wide c) these dimensions are subject to change when tried in the mouth

8.

Technique for Adjusting Wax Occl. Rims (at the pt. appointment) a) maxillary - adjusted 1-2mm below the edge of the resting upper lip b) maxillary - adjusted posteriorly to a parallel line from ala of nose to superior edge of tragus (Camper’s line) c) maxillary - when viewed from the front, the rim should parallel the interpupillary line d) mandibular - rim should be at or below the corners of the mouth at the first bicuspid area e) mandibular - rim should project posteriorly over the ridge and 1/2 to 2/3 up the retromolar pad

9.

Two main types of facebows: a) kinematic b) arbitrary

10. 11.

Purpose of facebow transfer - to transfer the relation of the maxilla to the rotational centers (hinge axis) Significance of possible errors - could be negligible if interocclusal records were at precise CR and if zero degree posterior teeth were used in a non-balanced occlusal scheme Indications for facebow use: a) cusp form teeth b) balanced occlusion c) interocclusal records to verify

12.

4


Comp. Remov. Prosthodontics Burleson Lecture 5 : Facebow and Maxillomandibular Relations 1.

a) kinematic facebow - actual transverse horizontal axis is located; not practical for use in edentulous pt. b) arbitrary facebow - average point is used to approximate transverse horizontal hinge axis location - approximately 13mm anterior to the middle of the tragus of the ear - this arbitrary point translates to an error of 2mm or less in most patients

2.

Purpose of a Facebow Transfer Procedure is to record the maxillary relationship to the transverse horizontal axis and then transfer this relationship to the articulator - this process orients the maxillary cast to the opening axis of the articulator in the same way that the maxilla is related to the opening axis of the patient

3.

Possible Errors if Facebow Is Not Used a) errors in occlusion of the denture b) errors would be negligible if all interocclusal records were made precisely at proper occlusal vertical dimension and if zero degree posterior teeth were used in a non-balanced occlusal scheme

4.

Facebow must be used: a) cusp form teeth are used b) balance occlusion is used c) interocclusal records are used d) or occlusal vertical dimension may change

5.

Define a) vertical dimension - a vertical measurement of the face between two arbitrarily selected points b) phsiologic rest position - position of the mandible when the elvator and depressor muscles are in balance c) rest vertical dimension - vertical dimension of the face when the mandible is at the PRP d) occlusal vertical dimension - vertical dimension of the face when the teeth are in contact in CR e) interocclusal distance - distance between occluding surfaces of max. & md. teeth when md. is at PRP - the average interocclusal distance is 2-3mm at the bicuspid region - occlusal vertical dimension = PRP minus 3mm f) closest speaking space - closest relationship of the occlusal surfaces and incisal edges of md. teeth to max. teeth during rapid speech

6.

How to determine occlusal vertical dimension using PRP = subtract 3.0mm from PRP and confirm by: a) patient’s facial appearance being acceptable b) parallelism of residual ridges of the mounted casts c) phonetic evaluation at the trial placement appointment d) tactile sense of the patient

7.

Phonetics & Esthetics a) phonetics - M can be said without teeth, P leaves lips apart for observation of interocclusal space b) esthetic harmony of lower 1/3 of face; contour of lips; appearance of skin from lower lip to chin

8.

Swallowing Threshold - natural teeth contact at the OVD during swallowing; muscle memory may remain

9.

horizontal maxillomandibular relations include CR and protrusive records as well as lateral excursions vertical maxillomandibular relations include VD and PRP

10.

Why is CR used as horizontal reference position? Other horizontal jaw relations are deviations occuring in the horizontal plane. They are grouped together as eccentric relations.

11.

How to help pt. retrude the mandible: “let jaw relax and pull it back”, “turn tongue backward toward max.”

12.

Eccentric relation records: protrusions, right and left lateral excusions, all intermediate positions may be used in determining the Christensen phenomenon or ensuring balancing occlusion

5


Comp. Remov. Prosthodontics Burleson Lecture 6 : Selecting and Arranging Artificial Teeth 1. Principles of selecting shade of anterior teeth: a) goal is to achieve harmonious blending of shade, shape, and arrangements b) shades should be compatible with patient’s general facial coloration and complexion c) best to give pt. 2 or 3 choices to avoid an extremely light tooth in an elderly patient d) canines are darker than lateral incisors e) tooth color darkens with age and females have lighter natural teeth than males 2.

Principles of determining size of anterior teeth: a) size of face: average width of maxillary central incisor is 1/16 the zygomatic width of the face b) combined width of the 6 maxillary anterior teeth is the bizygomatic width divided by 3.3 c) corners of mouth marked on wax rim and measure on a curve to give width of max. ant. teeth on a curve d) high lip line marked on wax rim when the patient smiles : measure to edge of rim for incisogingival length e) maxillary anterior teeth support the superior border of the lower lip

3.

Principles in selecting tooth mold / form: a) contour of face from frontal aspect should conform to outline of the tooth b) four types are square, square tapering, tapering, and ovoid c) determined by connecting the points: forehead, zygomatic process, angle of mandible d) shape of max. central incisor resembles the shape of the face if placed upside down (inverted) e) curved facial features are more feminine, square facial features are more masculine f) teeth lose their curves with advancing age; square form implies age

4.

Geometric Theory - tooth form is related to inverse shape of face measured at forehead, zygoma, mandibular angle lines - this has been scientifically disproven but artistically reasonable to keep teeth in harmony w/ surroundings

5.

Arrangement of Anterior teeth a) concerned with antero-posterior position; supero-inferior position b) angulation / inclination c) individual tooth position

6.

Landmarks for preliminary arrangement of anterior teeth: a) anterior teeth are arranged primarily for esthetics, not function (esp. true in non-balanced occlusion) b) maxillary anterior teeth are set on the smile line which follows the lower lip and in the midline of the face c) labial surface of max. central incisor is 8-10mm anterior to the incisive papilla d) arch form of the anterior teeth should be in harmony with the arch form of the ridge e) distal of cuspid should point to desired position of the central fossae of the posterior teeth f) there should be no contact of the maxillary anterior teeth with the mandibular anterior teeth g) the imagined roots of the teeth should not cross each other

7.

Landmarks for preliminary arrangement of posterior teeth: a) teeth should be arranged on lower denture to gain maximum retention b) not so far buccally that cheeks will lift the denture but not so far lingually that tongue will lift the denture c) mandibular posterior teeth are placed over the center of the ridge d) maxillary posterior teeth are placed to occlude with the mandibular teeth

8.

Guidelines for determining location of occlusal plane: a) esthetics b) anterior tooth placement c) retromolar pads

9.

Landmarks which dictate the posterior limit of teeth on a mandibular denture a) measure from distal of canine to the retromolar pad where mean residual ridge turns upward - this will give you the Mesio-Distal length of the posterior teeth b) posterior teeth should never be placed over the incline / upward slope of the residual ridge c) incisogingivally: the interarch space determines the IG length and 2/3 up the retromolar pad

10.

Maxilla resorbs: vertically and medially in the posterior and vertically and palatally in the anterior Mandible resorbs vertically and laterally in the posterior and vertically and slightly lingually in the anterior

6


Comp. Remov. Prosthodontics Burleson Lecture 7 : Occlusion in Complete Dentures 1. Natural Teeth a) periodontal tissue is innervated b) individual pressures of occlusion and move independently c) non-vertical forces affect only the teeth involved d) proprioception allows patient to avoid prematurities and interferences Artificial Teeth a) move as a unit on their base b) non-vertical forces affect all of the teeth on the base c) incising with artifical teeth affects all teeth on the base d) lack of proprioception means prematurities cause the bases to shift on the tissue 2.

Bilateral Balanced Occlusion: a) stable, simultaneous contact of opposing max. and mand. posterior teeth in CR and eccentric movements b) smooth bilateral contacts from CR to any eccentric position (usually not beyond edge-to-edge position) c) contacts on non-working side should exist; must not interfere with the gliding movement of working side d) may use anatomical or zero-degree teeth e) requires precise jaw relation records and is very challenging technically f) indicated in young, healthy ridges with good neuromuscular control, class I , vertical overlap of ant. teeth Monoplane / Neurocentric Occlusion: a) non-anatomic teeth set on a flat plane which bisects the area between max. and md. ridges b) no occlusion over the incline / slope of md. ridge with occlusal plane height = 2/3 up the retromolar pad c) no effort is made to achieve gliding contacts in eccentric movements d) indicated in excess interarch distance, poor neuromuscular control, severe ridge resorption, class I I & III crossbites, no vertical overlap of anterior teeth Lingualized Occlusion a) maxillary posterior teeth are anatomic cusp form; mandibular posterior teeth are 0° or 10° teeth b) teeth may be set on flat plane (non-balanced) or on a compensating curve (balanced) c) buccal cusps of max. teeth are raised up off the occlusal plane and do not contact md. teeth d) combines advantages of cusp form teeth with advantages of zero degree teeth e) indicated in class I , II, III jaw relationships; crossbites; where esthetics paramount

3.

Hanau’s Quint a) Incisal guidance (IG) b) condylar guidance (CG) c) plane of occlusion (PO) d) cusp height (CH) e) compensating curve (CC)

Thielemann’s Formula for balanced occlusion IG x CG = PO x CH x CC Bal. Occl. = (IG*CG) / (PO*CH*CC)

4.

a) compensating curve - the anteroposterior (Spee) and mesiolingual (Wilson) curvature of occluding surfaces and incisal edges of artifical teeth used to develop balanced occlusion b) Christensen’s phenomenon - slope of articular eminence causes the post. teeth to separate in protrusion c) incisal guidance - influence of contacting surfaces of max. and md. anterior teeth on md.movement d) condylar guidance - md. guidance generated by the condyles traversing the contours of the glenoid fossa

5.

Balanced Occlusion a) stable, simultaneous contact of opposing max. and mand. posterior teeth in CR b) and continuous, smooth bilateral gliding contacts from this position to any eccentric position Non-balanced Occlusion a) teeth are arranged on a single plane b) condylar and incisal inclinations are set at zero c) no attempt is made to eliminate deflective contacts in protrusive or lateral movements

7


Comp. Remov. Prosthodontics Burleson Lecture 8 : The Trial Placement 1. Rationale for evaluating trial record base stability and extension: - stable record base is mandatory for accurate jaw relationship records and phonetic & esthetic evaluations 2.

Methods for establishing the rest vertical dimension of an edentulous patient: a) stretch-relax method : open wide for 15-20sec. and then relax and close until lips together b) swallow-relax method : reverse of the stretch-relax c) closest speaking space : if contact occurs, OVD is too far open / excessive - count from 60 to 70 : teeth should be about 1mm apart - if there is greater separation : OVD is too far closed / inadequate

3.

Methods for assessing OVD at the trial placement appointment: - patient’s observations : pt. will be able to tell if the jaw closure feels or looks about right, too open or closed - does the lower third of the face look about right / too far open / too far closed ? - recall there is no precise scientific method to determine OVD but there are several usually reliable methods - if the OVD is in error of +/- 3mm or more = new centric relation made and md. case remounted & reverified

4.

Verify mounting (CO = CR): - intraoral observation of a guided retruded closing by the patient - make interocclusal record (new CR record) = no penetration of the posterior teeth through the material

5.

Landmarks and methods in evaluating lip support: - evaluate nasolabial sulcus, mentolabial sulcus, philtrum of lip, commissures of lip - inadequate support: sulci deepened, philtrum flattened, commisures droop, vermilion border decreased - too much support: sulci shallow, philtrum curvature is gone, commisures distorted laterally, tight lips

6.

Evaluation of esthetics: - color, size, form are evaluated; check midline; check smile-line - do the 6 anterior teeth support the lip and extend to the corners of the mouth? - canines at corners of mouth (max) and buccal corridor should be evident between teeth and cheek

7.

Evaluation of phonetics: - more reliable in patients who have worn dentures before - S sound: if patient whistles (palate too narrow); if S sounds like SH (palate too wide) - T sounds like D (max. teeth too far lingually) - D sounds like T (max. teeth too far labial)

8.

Evaluation of occlusal plane: - initially determined in the facebow jaw relation record by paralleling the interpupillary line with occlusal rim - anteriorly: determined by esthetics and phonetics - posteriorly: made parallel to the ala-tragus line; no more than 2/3 up the RM pads on lowers - occlusal surface should be 2-3mm below the dorsal surface of the tongue

9.

Protrusive record: - used in balanced occlusion; must have condylar guidance to set on the articular - pt. protrudes at least 6mm and the translation of condyles down the articular eminence is recorded

8


Comp. Remov. Prosthodontics Burleson Lecture 9 : Denture Base Resins 1. Define the following: a) resin - natural or synthetic substances that form plastic materials after polymerization b) polymerization - chemical reaction by which mers form polymer; never entirely complete; always monomer c) activator - heat, chemical, light, microwave : four methods to activate the initiator of polymerization d) initiator - releases free radicals to initiate chain reation when activated (benzoyl peroxide) 2.

Heat activated denture base resins a) benzoyl peroxide initiator (powder) b) heat activator

Chemically Activated Denture Base Resins a) benzoyl peroxide initiator b) tertiary amine activator in the monomer

3.

Liquid components a) methylmethacrylate b) hydroquinone inhibitor c) glycol dimethacrylate

Powder Components a) polymethylmethacrylate beads b) pigments c) benzoyl peroxide d) plasticizer - dibutyl phthalate

4.

Trial Closure: - or “trial packing” is a preliminary closing of the flasks under pressure to ensure the mold is completely filled - this will eliminate excess material and ensure a complete fill; if not = add more resin

5.

Two polymerization cycles for heat-activated denture resin a) 165° for 1.5 hours then 212° for 30min. b) 165° for 9 hours (no thermal boiling)

6.

Polymerization: - when the resin rises above 60°C (140°F) the benzoyl peroxide decomposes to free radicals - free radicals react with monomer and new free radical is formed - this is exothermic and temperature may rise above 100°C = internal porosity due to monomer boiling - this occurs in the thick sections of the resin; boiling point of monomer is 100.8°C Chemically-activated: degree of polymerization is less than that of heat activated; color stability is inferior

7.

Properties of Denture Base Resins a) polymerization shrinkage = 8%; contributes very little to the linear shrinkage b) thermal shrinkage : the main contributor to linear shrinkage seen (0.2% to 0.69%) are typical c) the result of linear shrinkage : palatal portion lifts away from the tissue = increase in OVD d) porosity - monomer boils; lack of homogeneity in dough; inadequate pressure e) water absorption - PMMA absorbs water slowly f) strength - heat from polishing wheel may cause denture warpage; depolymerization and dec. strength

8.

Resilient Liners: - elastomer polymers are heat processed to the hard resin denture base - used to prevent chronic soreness - useful life of months to years (2-5) - ethylmetharcylate, vinyl resins, silicon rubbers, polyurethanes Tissue Conditioners - highly plasticized acrylic resins - temporary soft relinsers useful for only days - weeks - polyethylmetharcylate (Coe Comfort, Coe Soft, Lynal)

9.

Lab remount - done to compensate for any gross occlusal adjustments needed due to processing - this step can be skipped : the clinical remount is much more important Facebow preservation index - made before the denture is broken off the master cast - bring plaster up to cusp tips of maxillary denture teeth remounted on articulator = preserves facebow Clinical remount - much more important; max. remount cast is mounted using facebow preservation index

9


Comp. Remov. Prosthodontics Burleson Lecture 10 : Denture Insertion 1. Prior to patient’s arrival for denture insertion a) polished surfaces are smooth and devoid of scratches b) no imperfections on tissue surface c) borders are round with no sharp angles d) maxillary remount cast has been mounted using the facebow preservation index e) mandibular remount cast is prepared and ready for pt. appointment (clinical remount) 2.

Evaluating and Adjusting the Basal Seat / Tissue Side a) check for undercuts b) paint the intaglio surface with pressure indicating paste : thin coat c) seat denture slowly and remove to inspect d) confirm any pressure areas with a second insertion and inspection = relieve denture base

3.

Evaluating and Adjusting Border Extension a) borders should lightly contact the vestibule b) overextension: commonly seen at frenae and db corner of mandibular c) apply disclosing wax on the borders d) deepen frenae notches but do not widen

4.

Refining Occlusion a) new centric relation record made at slightly increased OVD (no contact of post. teeth) b) remove registration, trim, attach dentures to casts, lengthen incisal pin 4mm, mount md. cast c) verify accuracy of mounting with second interocclusal record in CR = if cusp tips don’t fit : re-mount d) adjust occlusion: ensure bilateral simultaneous contacts of all post. teeth; absence of ant. contact e) evaluate OVD : speak silibant sounds; no contact of teeth (if contact= OVD too far open) f) smooth and polish all surfaces which were ground

5.

Instructions to Patient a) do not chew with front teeth; chew slowly b) rest the tongue on the floor of the mouth c) read the newspaper aloud; cover mouth when sneezing / coughing; remove immediately if nauseated d) clean after eating; brush palate and tongue; keep dentures in water when not in mouth e) have mouth and dentures examined every 12 months * pt. must be seen for follow-up the day after dentures are delivered = no delivery on Friday * no requirement to give the patient the dentures at this appointment - may simply adjut intalgio surface, make centric relation records, remount and dismiss pt. - then the patient won’t see you “grinding on their new dentures”

10


Comp. Remov. Prosthodontics Burleson Lecture 11 : Post-Insertion Follow-up Appointment 1. Rationale for post-insertion follow-up appointment the day after insertion - if this appointment is not scheduled, it is implied that the treatment is complete upon insertion of the CD 2.

Evaluating dentures and mucosa at 24hr follow-up a) esthetics - best treated by prevention b) phonetics - silibant sounds distorted, fricative sounds distorted, clicking during speech c) tissue irritations d) retention / stability

3.

Tissue irritation on the crest of the ridge - suspect deflective occlusal contact; or possibly a sharp crest of ridge or irregularity on intaglio surface - correct with remount and selective grinding - pressure from denture base: diagnose with pressure indicating paste and relieve

4.

Common phonetic problems a) whistle when “S” = anterior palate too narrow b) lisp when saying “S” = anterior palate too broad c) “f” sounds like “v” = anterior teeth too long d) “v” sounds like “f” = anterior teeth too short e) clicking during speech = OVD too far open (too great) = interocclusal space is too small

5.

Soreness in the Vestibular Areas - suspect unpolished or poorly polished denture border, sharp border, or overextended border - use PIP or disclosing wax to verify correct area and provide slight relief

6.

Soreness on the Slopes of the Ridges - suspect occlusal disharmony (CO does not equal CR) or deflective occlusal contact - check occlusion = is initial contact of the posterior teeth uniform? bilateral? simultaneous? - remount, verify accuracy of mounting and perform selective occl. grinding

7.

Causes of biting of the tongue, cheek, lips - suspect inadequate horizontal overlap of teeth; OVD is overclosed, - inadequate space between bases in the posterior, incorrect location of the occlusal plane - tx. may require modifying or replacing / resetting some teeth

8.

Soreness on the median palatal raphe - suspect insufficient relief of raphe area, anterior teeth contacting in CR - if palatal irritation appears 1-2 days after insertion = probably insufficient relief - if max. denture moves forward and upward = probably anterior teeth contacting

9.

Treatment and causes of Dislodgment of Denture a) drops when yawning - excess thickness of DB flange area or underextended border, or post. palatal seal b) drops when talking - posterior palatal seal, peripheral seal, underextension or overextension c) drops when laughing - inadequate border extension (over and under-extended) d) initially retentive but loosen after few hours - erros of occlusion or character and flow of saliva e) general lack of retention - examine occlusion, border seal, and contour of denture base and borders

10.

Dislodgment of the Mandibular Denture (common) a) occlusal disharmony b) thick neutral zone c) contour of cameo surface d) retractive tongue position: (occlusal plane too high, arch too narrow, anterior teeth too lingual)

11.

Gagging and Deafness / Earache - immediate = suspect OVD too far open; overextended posterior border of max.; post. border too thick - 2weeks - 2mos = suspect malocclusion causing dentures to loosen, incomplete border extension - deafness or earache = OVD too far open (earache); OVD too far closed (deafness)

11


Comp. Remov. Prosthodontics Burleson Lecture 12 : Edentulous Exam and Diagnosis 1. Patient Profiles (House) a) philosophical - learns to adjust rapidly; most favorable pt. type b) exacting - critical, skeptical, questioning, has high expectations. c) hysterical - emotionally unstable, apprehensive, chronic disease, expectations out of line; most difficult d) indifferent - not cooperative, unconcerned, does not follow instructions, guarded to poor prognosis 2.

Problems with arch size and form - mandibular arch may be larger (wider) than the maxillary arch - due to resorption patterns - square and ovoid give better denture stability - flat ridge and knive-edge ridges = poor prognosis

3.

Ridge relationships - excess interarch space = increased lever on the dentures - class III = usually need greater interocclusal space - at OVD : need 4-6mm of space between the tuberosities (enough room for both denture bases)

4.

Bony contours - path of insertion of denture allows anterior undercut (max.) as long as no undercuts in posterior - retromylohyoid undercut (md.) usually permissible as long as there is not excessive anterior undercut - would not want to remove bone from the anterior mandibular ridge = it resorbs far too fast for that!

5.

Palatal vault a) U-shaped = most favorable b) V-shaped = less favorable - usually seen with class II or III soft palate c) flat hard palate = not favorable; not enough horizontal stability & retention decreased

6.

Soft Palate Classification - based on width of posterior palatal seal area and degree of flexure - more gradual degree of flexure = more favorable the soft palate form a) Class I soft palate = gradual flexure beginning 5-12mm begind junction of hard and soft palates b) Class II soft palate = turns downward at 45° angle beginning 3-5 mm behind junction of hard & soft palates c) Class III soft palate - turns down abruptly, just behind junction of h. and s. palate; least favorable - class III has extreme movement of the soft palate = can give loss of retention of max. denture

7.

Wrights Tongue Classification a) Class I : tongue lies relaxed in floor of mouth; most favorable b) Class I I : tongue flattened and broadened, but tip is in normal position c) Class III: retracted tongue; 25% of patients; will most likely have retention problems with md. denture

8.

Establish Treatment Plan a) I s surgery indicated? b) Can you meet the patient’s expectations? c) I s the prognosis good, fair, or poor?

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Comp. Remov. Prosthodontics Burleson Lecture 13 : Immediate Complete Dentures 1. Advantages of Immediate Dentures a) prevent patient embarrassment b) facilitate optimal esthetics - denture teeth can be placed where natural teeth were c) denture acts as a bandage over the surgery sites - less pain d) hastens pt. adaptation to dentures (if completely edentulous for awhile = learn new habits, must unlearn) 2.

Disadvantages of Immediate Dentures a) no trial placement and evaluation before processing b) increased complexity of taking impressions, etc. c) increased denture maintenance = relines, adjustments, occlusal equilibrations while healing d) more pt. visits = more expensive

3.

Contraindications for Immediate Dentures a) pt. undergoing irradiation therapy to the head and neck (decreased healing, xerostomia) b) systemic conditions affecting blood clotting, wound healing, tissue regeneration (diabetic, hematologic) c) aged or medically compromised who cannot tolerate multiple extractions (osteoporosis, vascular, etc) d) malposed teeth / alveolar bone requiring extensive surgery e) psychological conditions f) pt. that is not willing to forego increased maintenance and expense

4.

Diagnosis and Treatment Planning Immediate Dentures a) educate patient about their role and all of the problems associated with immediate dentures b) tori, tuberosities, frenal attachments : surgery? c) preliminary casts are made d) two phase surgical schedule is preferred 1. remove posterior teeth, retain first premolar to preserve OVD; surgical corrections, wait 6-8wk. 2. extraction of anterior teeth, frenectomy, minoralveoloplasty if needed, insertion of CIDs

5.

Impression Techniques a) custom impression tray for 2째 impression - blockout teeth, border mold the tray, flexible impression mat. b) combination impression - custom tray made for edentulous areas and palate - border mold, make secondary impression of palate and posterior edentulous areas - place this impression back in the mouth - make another impression using stock tray over the custom tray (irreversible hydrocolloid)

6.

Rationale for posterior try-in a) verify centric relation mounting b) allow patient to see on articulator and accept

7.

Post-delivery instructions a) do not remove for 24 hours b) may wear at night for first 2-3 days c) avoid mouthwashes containing alcohol d) will need reline / rebase / remake in 3-6 months e) soft diet for awhile

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Comp. Remov. Prosthodontics Burleson Lecture 14 : Single Denture Opposing Natural or Restored Teeth 1. Significance of the Horizontal Discrepancy between Edentulous Ridge and Opposing Natural Teeth - routine morphological changes result in generally smaller maxilla following extraction - this creates a horizontal discrepancy between the arches anteriorly and posteriorly - makes it difficult to direct occlusal forces to the denture-bearing surfaces : support is at a distance - best strategy: place the teeth in a reverse horizontal overlap or crossbite arrangement 2. 3.

Biomechanical problems encountered when single maxillary denture is opposed by natural ant. teeth only - called the “combination syndrome�: occlusal forces are concentrated in the anterior region a) severe maxillary anterior bone resorption b) inflmmatory papillary hyperplasia (IPH) c) downgrowth of maxillary tuberosities d) severe resorption of md. posterior alveolar ridges e) supraeruption of md. anterior segment

4.

Irregular occlusal plane in natural dentition arch opposing a single denture - any equilibration should be done before denture fabrication - will displace the maxillary denture, cause soreness and mucosal irritations, and accelerate ridge resorption - need opposing teeth at least to the first molar area (bicuspids may work for class I I retrognathic)

5.

Correcting the Occlusal Plane - if teeth are extruded beyond the desired occlusal plane, they should be reduced, restored, or removed - functionall generated path: adjust the natural teeth, then adjust the denture teeth - balanced occlusion is used against md. natural dentition

6.

Problems of Single Denture a) wear of natural teeth : only if artificial teeth are porcelain b) wear of resin teeth by natural teeth (not much of a problem today) c) fracture of denture base : bruxism, heavy anterior contact, deep frenal notch in max. denture

7.

When to recommend a RPD - insufficient number of teeth in the mandibular arch opposing the maxillary single denture - we want opposing teeth at least halfway back between incisive papillae and hamular notches - this is to prevent anterior alveolar rige loss - usually means occlusion to the first molar area, but could have premolars only in Class I I retrognathic

8.

Mandibular single denture opposing natural teeth - some authors say this is contraindicated (Swanson 6th ed.) - prognosis is usually dismal - support: 12cm2 in md; vs. 23 cm2 in maxillary denture (compared to 45cm2 PDL space in each nautral arch) - may want to consider implants, overdenture, resilient liner, or remove max. teeth and make 2 dentures

9.

Bilateral balanced occlusion - preferred occlusal scheme for single dentures - gliding contacts in eccentric movements are believed to help keep the maxillary denture stable & retentive - this includes anatomic balanced and lingualized balanced occlusion

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Denture Lecture Notes