Pros Final Flashcards
Can gutta percha be removed immediately after endodontic treatment and post space prepared?
Adequately condensed gutta percha can be safely removed immediately after endodontic treatment
value v hue v chroma
value brightness
bue color
chroma saturationvalue most important
Mutually protected occlusion
“ The posterior teeth protect the anterior teeth and the anterior teeth protect the posterior teeth”
Characteristics:
- MIP occurs with condyles in centric relation
- Posterior teeth “hold shim”
- Anterior teeth “drag shim”
- Immediate separation (no contacts) of posterior teeth in any eccentric movement
- Anterior guidance: anterior teeth provide separation of posterior teeth in eccentric movements
Exposure of centrals in youth during long E
50-70%
Post cement options
Zinc Phosphate
Glass Ionomer
Polycarboxylate
Resin
Resin modified glass ionomer
how much central exposed during “Emma”
youth: 1-4mm
Cement retained implant crown occ
- Lighter than natural teeth**
- 30 microns vertical depression
- Implants not depressible
- Instruct patient to clench
- Drag two thicknesses of shim
- Eliminate excursive contacts
- Consult centric relation
- First point of contact
- CR-MIP slide
Full coverage guidelines for anterior teeth after endo
Anteror teeth are subjected to lateral forces
For anteriors, full coverage = crown
Crown not required: Intact marginal ridges, conservative endodontic access, acceptable esthetics
Crown required: Inadequate remaining coronal tooth structure, FDP abutment, RDP abutment, unacceptable esthetics (there is another option…veneer)
Most anterior teeth that require a crown also require a post
Manufacturer rec screw torque
- 3i –20 N-cm
- Nobel –35 N-cm
75% of average failur torque of screws
Interim restoration definition
A transitional restoration that provides protection, stabilization, and functionbefore fabrication of the definitive prosthesis. It may also be used to determine the esthetic, functional, and therapeutic effectivenessof a treatment plan.
The resistance triad
Antirotation
ferrule
remaining vertical tooth structure
proper axial reduction is…
2 mm functional cusps
1.5mm elsewhere
Reasons for PVS in implant impressions
- Rigidity
- Accuracy
- Can pour multiple casts
- High dimensional stability
- No odor/unpleasant taste
When exporting dicom to use with bluesky, what must you do
Ananomize the file
What are the parts of a clasp?
- Rest
- Body
- Shoulder
- Reciprocal Arm
- Retentive Arm
- Retentive Terminal
- Minor Connector
- Approach Arm
Tongue size
House
Class 1: Normal size, development, functionSufficient teeth present to maintain normal form/function
- Class 2: Teeth have been absent long enough to permit a change in the form and function of the tongue
- Class 3: Excessively large tongueAll teeth have been absent for an extended period of time, allowing for abnormal development of the size of the tongue
Inefficient dentures can lead to the development of Class 3 tongue
Advantages of cast post
Universal application
Customized, intimate fit
Best core to post adaptation
Increased control: core fabrication/angulation
Built-in antirotation
when scanning cast what KVP and MA should be used
80/10
biomet 3i colors and sizes
pink 3.25
blue-4mm
yellow-5mm
green-6mm
Post insertion maintenance
changes in the residual ridge
chairside soft relines every 3+ weeks prn
at about 6 months hard reline or make remote denture
occlusalequilibration/clinical remount
Resin cement
Virtually insoluble
High compressive strength
Very technique sensitive!
Need auto-cure capabilities, not dual cure!
The eugenol effect
Casts should be soaked in what before trimming?
SDS! DO NOT TRIM A DRY CAST?
What material should be avoided using the direst interim technique
PMMA
should use bis acryl instead
Do endodontically treated teeth need crowns?
Sorenson and Martinoff, JPD 1984•1233 teeth, 1-25 years
- Anteriors –no significant improvement
- Posteriors –significant improvement
“Crowns should generally be used on endodontically treated posterior teeth but are not necessary on relatively sound anterior teeth.”
indication for a post in a premolar
Difficult to restore
Lack of :•Dentin walls to retain core
- Dentin to place pins
- Vertical support for post
Delicate root anatomy
Consider custom post/core if increased function
Decision based on remaining tooth structure following crown preparation
Retain all sound dentin
Tear strength and resistance to deformation increases or decreases with time?
Increases
Reason for selecting prefab post/direct core
- Almost any clinical situation other than those listed as indications for the cast post/core
- There are almost as many prefabricated post systems as there are clinical situations in which to employ them
Cast post disadvantages
More tooth structure
removed
Increased time and cost
Requires temporization
Tapered form
Critical fit
requirements/stresses
Increased root fracture
potential
Define CR?
The maxillo-mandibular relationship in which the condyles articulate with the thinnest avascular portion of their respective disks with the complex in the anterio-superior position against the slopes of the articular eminencies. This position is independent of tooth contact.
Rule of thirds cast modification
Jerbi ‘66
Assumes normal periodontal relationship
Teeth decoronated1.0mm sub-FGM
gingival, middlem vestibular thirds
Stone-Plastygingival third to mid third
- depth: labial recess of teeth
- Represents collapse of labial gingival tissusetoward
preserve incisive papilla
Adv and disadv of tapered posts
Conservation of tooth structure•Less dentin removal than parallel or cast
Stress distribution•No sharp corners at terminus (vs. parallel)
Retention•Least retentive
analogue
replica
Schneid & Mattie Classification
–A modification of the Kennedy Classification
–Indicates arch configuration, and implant location
What are 4 Mandibular Major Connectors?
- Lingual Plate
- Double Lingual Bar
- Labial Bar
- Lingual Bar
Advantages of interim RPD
Tongue and facial musculature position virtually unaltered
Allows for “normal”chewing
Provides comfort, esthetics, learning period
Healing period can be extendedMore stable foundation
Allows continued diagnostic evaluation
May help with acclimation to removable prosthesis
Adv and disadv of PMMA
•Advantages
–Good marginal fit
–Good transverse strength
–Good polishability
–Durability
•Disadvantages
–High exothermicheat increase
–Low abrasion resistance
–Free monomer toxic to pulp
–High volumetric shrinkage
Things to assess in existing dentures
Esthetics
Phonetics
Retention
Stability
Extensions
OVD
CR
Characterization
Palate (smooth?)
Wear
Comfort
Hygiene
Pt adaptation to denture
Mucosa
Thickness
Condition
- Normal
- Irritiated
- diseased
ways to get restorative anatomical symphysis
CBCT of cast
lab optical scan of cast or impression
optical scan of mouth
What is the optimal post length?
Lab study –ideal is ¾ root length
Post at least equal to crown length or two-thirds the length of the root, whichever is greater, while maintaining an apical seal
What are Applegate’s 8 Rules?
- Classifcation should follow rather than precede extractions that might alter the original classification
- If a third molar is missing and not to be replaced, it is not considered in the classification
- If a third molar is present and is to be used as an abutment, it is considered in the classification
- If a second molar is missing and is not to be repalced, it is not considered in the classification
- The most posterior edentulous area or areas always determines the classification
- Edentulous areas other than those determining the classification are referred to as modification spaces and are designated by their number
- The extent of the modification is not considered, only the number of additional edentulous areas
- There can be no modification areas in class IV arches. Any edentulous area lying posterior to the single bilateral area determines the classification
C contacts
•C contacts-Stamp cusps of maxillary teeth occlude with shearing cusps of mandibular teeth
What are some uses of diagnostic mounting?
- Simulation of jaw movements
- Analysis of occlusal plane
- Critical Analysis of occlusion and disoclusion
- Visualization of anatomy and restorations/how they relate to the opposing arch
- Abutment size and angulation
- Diagnostic preparations
- Analysis of available restorative space
- Analysis of edentulous spans
- Soft Tissue Corrective Procedures
Indications for a post in molar
Rarely need to retain core
Single prefabricated post in largest canal
Macromechanical and micromechanical (bonding) retention recommended
Core retained by threaded pins, amalgam pins, bonding, post
Bonding decreases with thermocycling and functional loading due to fatigue
What are the five principles that govern prep design
- Preservation of tooth structure
- Retention and resistance
- Structural durability
- Marginal integrity
- Preservation of the periodontium
What is a Kratochvil: I Bar?
- Mesial rest, distal rest in adjacent tooth
- I-bar placed at greatest prominence of facial surface of abutment tooth
- Guide plane: line angle to line angle reciprocation
- proximal plate on long distal guiding plane, from marginal ridge to the tooth-tissue junction and 2 mm onto attached tissue
- Must physiologically adjust metal-tissue contact area with chloroform/rouge
What are 5 factors in implant success?
Ferrule
- Crown restoration ferrule is important
- 1.5-2.0 mm dentin coronal to shoulder is critical
- Maintain facial/lingual dentin on anterior teeth
- *Crown lengthening or orthodontic extrusion may be required vs alternative
biomet 3i prosthetic connection
Certain internal connection
internal hex with click seating
Tongue position
Wright
Normal: Tongue fills the floor of the mouth confined by the mandibular teeth
lateral borders rest on the occlusal surfaces of posterior teeth
apex rests on the incisal edges of the anterior teeth
there is no aberration in tongue size or activity
Class 1 Retracted: Tongue is retractedfloor of the mouth pulled downward and is exposed back to the molar area
lateral borders raised above the occlusal plane
apex is pulled down into the floor of the mouth
Class 2 Retracted: Tongue is very tense and pulled backward and upwardapex is pulled back in to the body of the tongue and almost disappears
lateral borders rest above the mandibular occlusal plane
floor of the mouth is raised and tense
When should impression for final prosthesis be made
3-4 weeks after extraction
Adequate axial height of the prep should be
4 mm posterior, 3mm premoalr forward
A contacts
Shearing cusps of maxillary teeth occlude with stamp cusps of mandibular teeth
Elevations
“Cusp tips”
“– Marginal ridges”
“– Triangular ridges”
“– Central ridges (Buccal/ lingual contours)”
“– Supplemental ridges”
“Elements”
Polycarboxylate
Half the compressive strength of zinc phosphate
Some bonding to tooth structure
Some clinical handling difficulties
Palatal Sensitivity
Class1 Normal
Class 2 Hyposensitive
Class 3 Hypersensitive
Post Palatal Seal
Naylor
B contacts
Stamp cusps of maxillary teeth occlude with stamp cusps of mandibular teeth
•Most difficult to attain and maintain
Nobel biocare colors and sizes
pink-narrow platform 3.5mm
yellow-regular platform-4.3mm
blue- wide platform-5mm
green-6mm
average central size
What makes a good prep/restoration
- Appropriate reduction
- Retention
- Resistance
- Well-sealed margins
- Comfortable for the patient
- Esthetic final product
- Long-lasting crown
Man Ridge types
coping
covering
Depressions
–Supplemental grooves
–Developmental grooves
–Fossas
Occlusal Force Equations
- A+B contacts = stability
- C + B contacts = stability
- A + B + C = stability
- A + C only = maxillary teeth move buccally, mandibular teeth move lingually
- Bonly = maxillary teeth move lingually, mandibular teeth move buccally
What is the height of a locator combination
3.177
cuff height can vary from 1-6mm
What is the incidence of endodontics after tooth preparation?
3 –23 %
FDPs higher than single crowns
Problems later
rather than early
Adv of implant assisted rpd
–Distal extension support
–Reduced bone resorption
–Elimination of unestheticretentive elements
–Decreased stress on abutments
–Improved comfort and patient satisfaction
What are the functions of a rest?
- Direct forces along long axis of tooth
- Vertical Stop
- Can function as an indirect retainer in distal extension areas
- Prevents tooth extrusion, food impaction
- Correction of occlusal plane
Guidelines for full coverage of posterior teeth after endo
Posterior teeth are subjected to greater loads directed more vertically
Due to heavy loading and compromised tooth structure, posterior teeth always require “full coverage” after root canal treatment
For posteriors, full coverage = crown or cuspal coverage amalgam
Crown required: FDP or RDP abutment, premolar in the esthetic zone
Many posterior teeth that require a crown do not require a post
Bis acryl advantages and disadvantages
•Advantages
–Good marginal fit
–Low exothermic heat increase
–Good abrasion resistance
–Good transverse strength
–Low shrinkage
•Disadvantages
–Surface hardness
–Less stain resistance
–Limited shade selection
–Limited polishability
–Brittle
–Expensive
–Oxygen-inhibited layer
Advantages of Cusp to Fossa Occlusion
- Forces in line with the long axis of teeth
- Eliminates the “plunger cusp” effect
- Greater stability to the dental arch
- Less tendency towards tooth mobility
Post length recommendation
2/3 the root length
- 1/2 the length of the root in bone
- >Length of clinical crown
- As long as possible with 5 mm of remaining gutta percha
Ridge Parallelism classes
thickness and goals of surgical guide
2mm
- Goal: ridge fits the surgical guide= more predictable
- NOT relieve denture to fit the ridge = more post operative visits
What does beading the maxillary framework do?
- Beading depth and width of 0.5 - 1.0 mm
- Fades out 6 mm from free gingival margin
- Prevents collection of food under major connector
- Allows thinning of metal at borders
How should you wait before pouring an alginate impression?
No more than 12 minutes
Factors for implant success
Restorative plan
Accurate imaging
restorative/anatomical symphysis
precision guidance
surgical execution
What are the requirements for obtaining CR?
- Physiologic
- Comfortable
- Consistent when made
- Repeatable over time
- Not operator dependent
3 types of occlusal schemes
- Balanced
- Denture occlusion - Group Function
- Shared Function - Mutually Protected
- Canine Protected
When should clinical remount be done
at least 2-3 weeks..when swelling and edema have subsided
What are the 4 RDP components?
- Major Connector
- Minor Connector
- Rest
- Clasp Assembly
Dynamics of mandibular movement deciphered by C. Stuart
Recognized that patterns of occlusal surfaces are resultants of patterns of mandibular movement
Goals of gnathology
“1. CR occlusion 5. Cross-tooth stability”
“2. Uniform contacts in CR 6. Forces in the long axis”
“3. Cusp-fossa occlusion 7. Narrow occlusal table”
“4. Tripodism 8. Disclusion”
Group Function
Characteristics:
- Total stress distributed among many teeth
- No interferences from closure to intercuspal position
- No balancing interferences in eccentric movements
What are some requirements for a diagnostic mounting?
- Alginate impressions
- Diagnostic Casts
- Facebow Record
- Semi-adjustable articulator
- CR records
- Lateral and/or protrusive records
types of posts for premolars
- Pin or chamber retained core if adequate tooth structure following prep (i.e., conservative access)
- If post/core required, cast vs. prefabricated depends on canal anatomy:•Ovoid canal = cast post/core
- Circular canal = prefab (endowel, parapost)
Abutment level
pertaining to the abutment
What are 6 Maxillary Major Connectors?
- Posterior palatal bar
- Anteroposterior palatal bar
- Palatal strap
- Anteroposterior palatal strap
- Horseshoe
- Complete palate
What types of articulators are Arcon and Non-Arcon?
- Both are semi-adjutable
- Arcon: articulating condyle on mandibular element (whipmix) 3B
- Non-Arcon: condyle on the maxillary element (Hanau) 3A
Every effort must be made to avoid contact of the cast with…
Tap Water
Tearing increases or decreases with rate of removal?
Tearing decreases with increased rate of removal
implant level
pertaining to the implant
Reasons for good denture impression
Establish desired denture borders
Maximize retention and stability by defining maximized support coverage
Minimize flange adjustment at insertion
two implant systems we use
Nobel biocare
Biomet 3i
What is the flexiblity of clasps determined by?
- Length
- Taper
- Diameter
- Cross-sectional form
- Material
Immediate denture approaches
One-Phase Immediate:
-FM Extraction with immediate denture delivery
One-Phase “Delayed”:
-FM extraction with delivery 3-4 weeks post extraction
Two-Phased Immediate
- Extract posteriors (anterior), 6 weeks healing time, fabricate immediate denture, final extraction with immediate denturedelivery
- Prn Follow-up resilient liners (X2-3), hard reline or fabricate new final denture 8-12 months
What are some uses of diagnostic casts?
- Diagnostic Waxing
- Provisional Fabrication
- Survey and Design
- Radiographic Guides and Surgical Templates
- Design Custom Trays
Abutment def
supports and/or retains the prosthesis
Ridge relationship classes
What are the 4 steps to mounting a cast?
- Relate maxillary cast to the condylar axis (facebow)
- Relate the mandibular cast to the maxillary cast in centric relation position (CR record)
- Verify the accuracy of the mounting - 1st point of contact, AKA Centric Occlusion Contact)
- Set the OVD in MIP (incisal guide pin)
Disadvantages of implant assisted rpd
Additional treatment cost
- Additional surgical procedure
- Extended treatment time
- Careful treatment planning and interdisciplinary approach required
- Technique-sensitive
- Additional maintenance
- Manual dexterity required
Anterior Coupling/Anterior Articulation
•A comfortable articulation of anterior teeth that is necessary for anterior gudiance (separation of posterior teeth in eccentric movements.
Four rule in arch
> four —consider removable partial denture
< four —consider complete denture
Implant loading protocols
- Immediate = < 1 week
- Early = 1 week –2 months
- Conventional = > 2 months
- Immediate and early loading
- Insertion torque ≥ 20 –45 Ncm
- Absence of systemic or local contraindications
- Clinical benefits exceed risks
Post canal prep principles
- Seal unaffected by method of gutta percha removal…heat vs. rotary
- Seal unaffected by time of gutta percha removal…immediate vs. delayed
- Ideal: 5 mm of gutta percha
- Absolute minimum: 4 mm
Stamp cusps
–Maxillary lingual cusps
–Mandibular buccal cusps
•
Steps of the wax try in
Verify OVD
Verify CR mounting
Verify occlusalPlane
Verify position of teeth that are set
Selecting posts for molars
- Pin or chamber retained cores work well if have adequate tooth structure following preparation (i.e., conservative access)
- Post/core required if < 4mm remaining height above pulpal floor or no room for intracoronal retentive features
What are the most common post and core failures
Loosening of the post
Tooth fracture
what is used for interim cement space
rubber cement
What is the chemical reaction for alginate?
Prefab post advantages
Time…
Can usually be done in 1 appointment
Cost…
Less expensive than cast gold
Temporization…
Less hassle than with temporary post & core
Rationale for overdenture abutments
Maintain bone support
Possibly help with stability
Proprioception
Decrease combination syndrome
What are 4 ways to obtain CR?
- Chin Point Guidance
- Bimanual Manipulation
- Leaf Gauge
- Lucia Jig
Maximum intercuspation
a closed contacting and static relationship of the teeth (MIP –maximum intercuspalposition)
- Total contacting area may not exceed 4mm2
- Nature provides a consistency to occluding parts
–Elevations and depressions
–Cusps and fossae
–Ridges and grooves
Balanced occlusion
- Simultaneous cross-arch contacts during eccentric movements
- Theory: balanced and distributed horizontal forces lead to oral health and provide denture stability
- Indications: Complete Dentures
Group
Post cementation keys for max ret
Post surface irregularities: serrated, threaded or sand blasted…and vented
Passive but intimate fit to reduce film thickness
Canal space decontaminated
Lentulo spiral for cement placement
Slow, intermittent seating to reduce stresses
Gnathology
“Definition: the science that treats the biology of the masticatory system as a whole: i.e., the morphology, anatomy, histology, physiology, pathology and the therapeutics of the jaws or masticatory system and the teeth as they relate to the health of the whole body, including applicable diagnostic, therapeutic, and rehabilitation”
“dures.”
Post Retention triad
Post lenght
cementation
post style
biomet healing abutment numbers
Max Ridge and vault types
Active Posts
Derive retentive/resistance features by actively engaging into root-space dentin
May be either self-tapping or require a separate tapping procedure
Best to restrict use of active post to short canals (heroics)
Zinc Phosphate
Long clinical history
Good compressive strength and film thickness
Soluble in oral environment
What are the 3 philosophies of RPD Construction?
- Equalized Support (stress-breakers)
- Physiologic (functional) basing
- Broad stress distribution
marginal adaptation of indirect v direct technique
“The marginal accuracy of the treatment restoration made by the indirect technique was significantly better than that of those made by the direct technique.”Crispin BJ, Watson JF, Caputo AA. J Prosthet Dent, 1980
“The indirect technique produceda more acceptable gingival margin for the provisional restoration tested in the study.”Monday JJ, Blais D: J Prosthet Dent 1985
for 3 or fewer implants is there a difference beweent pick up and transfer impression tech
no
What is needed for the final denture lab set up
Facebow
Determine appropriate OVD
Centric relation record*
Select/verify denture teeth
Posterior palatal seal
Provide max and man esthetic parameters to Lab technician (midline, I length, reference tooth, etc.)
Disadvantages of immeadiate dentures
Time–more office visits
Patient management during on-going changes
Impressions –border capture can be difficult
Interocclusalrelation records –stability
limited or no anterior try-in
Where does stability come from in an RPD?
- Guide Planes
- Reciprocation
- Lingual Plating
- Rests
- Denture Base
At what point should you consider removable
when interarch space approaches 15mm
Classifications of partially edentualous ridges
–Kennedy
–McDermott
–Schneid and Mattie
Can a silver point maintain its apical seal when a portion will be removed during post preparation?
The removal of a portion of a silver point during post preparation causes apical leakage
PEMA advantages and disadvantages
•Advantages
–Good polishability
–Minimal exothermic heat increase
–Good stain resistance
–Low shrinkage
•Disadvantages
–Surface hardness
–Transverse strength
–Durability
–Fracture toughness
Tripoidal contacts
- Each cusp contacts three points on the opposing tooth
- Mesial to distal stability–by closure stoppers and equalizers
- Buccal to lingual stability–by A,B,C contacts
Lateral throat form
Neil classification
Describe a RPI Kroll?
- Mesial Rest
- Short Proximal Plate
- I-bar direct retainer (Mid F to MF)
What are 4 types of rests?
- Occlusal Rest
- Cingulum Rest
- Incisal Rest
- Lingual Rest
What are the indications for an RPD?
- Long edentulous span
- Resorbed ridge
- Reduced periodontal support
- Cross-arch stabilization
- No posterior abutment
- Physical or emotional problems
- Multiple edentulous spaces
- Esthetics
- Patient Desires
- Financial Implications
interim material choices
- Poly methyl methacrylate (PMMA)
- Alike, Duralay, Jet, Cr & Br Resin - Poly ethyl methacrylate (PEMA)
- Snap - Bis-Acryl
- Self-cure: Integrity, Protemp II
- Light-cured: Radica
Nobel connection types
External hex
internal connical
internal trichannel
Inter arch space classes
Anterior teeth post type selcetion rationals
- Cast post/core: coronally-flared canals, multiple preps, tapered roots, excessively wide or ovoid canals, small teeth (most man incisors)
- Prefab: Round roots with round canals that are not coronally flared, (most maxillary anteriors, mandibular cuspids)
Advantages of immeadiate dentures
Esthetics –remaining teeth assist denture tooth placement
Appearance is affected minimally
Mastication during healing phase
Patient health –no procrastination
Better healing –denture bandage
Better ridge form –controlled contours
Face Esthetics: cheek and lip support maintained
Occlusal vertical dimension*maintained
Quicker learning –speaking/eating during healing phase
Cement retain interproximal contacts
Drag one, hold two
What is a reasonable bulk of alginate between tray and teeth?
5-7 mm
Closed tray
impression tray with no opening
What must a clasp design provide?
- Vertical Support
- Stability (bracing)
- ENCIRLCEMENT
- Retention
- Reciprocation
- Passivity
Border attachements
Class 1: Attachments high in maxilla or low in mandible with relation to ridge crest (0.5 inches or more between level of attachment and crest of ridge).
Class 2: Attachment height in relation to the crest of the ridges between 0.25 and 0.50 inches.
Class 3: Attachment height is less than 0.25 inches from the ridge crest.
What is syneresis and imbibition?
Syneresis: Shrinkge due to water loss - gel filaments contact and squeeze out water
Imbibition: alginate abosrbs water (swells) on immersion
Frenum attachment classification
Class 1: High in the maxilla or low in the mandible with respect to the crest of the ridge
Class 2: Medium
Class 3:Frena encroachon crest of the ridge and may interfere with the denture seal Surgical correction may be required
Equalizers
•PURPOSE
–Equalizes forces exerted by closure stoppers, providing mesial-distal stability
•LOCATION
–Mesial incline of maxillaryposterior teeth
–Distal inclines of mandibularposterior teeth
How much alginate and water would you need ideally?
28 gm alginate/68-72 cc Distilled water
Reasons for chosing cast post and core
- Multiple post/core preps
- Crown realignment
- Excessively flared or elliptical canals
- Small teeth -retention of core to post
Seven points of the mandibular plane
- Point 1 –incisal edge of man central incisors (anterior point)
- Points 2,3 –man first premolars at height of commissures
- Points 4,5 –lingual cusps of man first molars at level of lateral border of tongue
- Points 6,7 –flat plane from ant point to DB cusps of man second molars will bisect retromolar pads (all other cusps below this plane)
Two phase surgical schedule
Phase I: removal of posterior teeth (and other hopeless teeth)Fabrication of interim RPD immediate or delayed 10-14 days
Phase II: removal of remaining anterior (posterior) teeth immediately prior to denture deliveryApproximately 6 weeks after initial extractions
What are 4 characteristics of Major Connectors?
- Rigidity
- Avoid impingment of the free gingival margin
- Avoid creating food traps
- Patient comfort
Parallel PostsAdvantages and Disadvantages
Retention•More retentive than tapered post
Greater removal of dentin•Remember: Any dentin left behind provides strength
open tray
impression tray with opening at the impant site
How much gutta percha should be retained to preserve the apical seal?
4 –5 mm
5 mm is best and safest
GI
Same compressive strength as zinc phosphate
Bonds to tooth structure
What are 4 clasp designs?
- Circumferential Clasp
- Bar Clasp
- Suprabulge
- Infrabulge
What are the uses of a 3 piece cast analysis?
- Instant Equilibration
- Evaluation of anterior coupling
- Mutually protected articulation
- Reasonableness of restoring in CR
Pankey Mann Schuyler Tx goals
- MIP with condyles in Centric Relation
- Group function on working side
- Non-interference of posterior teeth on non working side
- Anterior guidance during lateral excursions and disclusion of posteriors in protrusion
- Anterior coupling but within 0.1 to 0.5 mm –Long Centric
- Posterior occlusal contact “areas” rather than tripodizedcontacts
Contraindications of immeadiate dentures
Frank pathology / Medical expediency
Extreme mal-relation of jaws
Patient preference: resistance to additional procedures
What are the prep parameters of an occlusal rest?
- Triangular and concave shaped
- Rounded Apex
- Should follow the fossa outline
- Inclined towards the center of the tooth
- Should allow for minimum 1.0 mm metal thickness
Pt instructions after denture insertion
Keep denture in for the first 24 hrscontrols bleeding
aids in clot formation
decreases swelling
1stweek –adjustments prn
Care of oral tissues
Care of dentures
Nutrition/hydration
What is the minimum space requird for a lingual bar?
- 8 mm from the gingival margin to the floor of the mouth
- 3 mm from free gingibal margin to superior border of the bar
- The bar should be at least 5 mm in heigh
What are the labeled patrs of an implant
- A = 0.7 mm hex height
- B = collar height
- E = implant diameter
- G = Threaded length (body)
- K = apex diameter
- L = collar diameter
- M = hex width
Screw retained implant crown interproximal contacts
- More difficult in posterior
- Drag two thicknesses of shim*
- No binding on adjacent teeth
Clossure stoppers
PURPOSE
–Stops closure of mandible as it relates to maxilla
–Neutralizes forces exerted by equalizers
•LOCATION
–Distalincline of maxillaryposterior teeth
–Mesialinclines of mandibularposterior teeth
Shearing cusps
–Maxillary buccal cusps
–Mandibular lingual cusps
Criteria for selecting abutments
Periodontal status
Endodontic potential –treatable??
Positional considerations –how many and where??
Caries status
- No < 6 mm of root supported by bone
2 Considerable horizontal and vertical mobility - poor choice
3 Band of attached gingiva – no < 2mm
Two canines –most common but may not be the best choice(canine eminence)
Avoid tissue undercuts
Adjacent abutments –unacceptableSpace of at least one tooth width apart
Opposing abutments –contraindicated inter-occlusalrestorative room
*Caries status must be assessed carefully*
Advantages of indirect interim technique
-Stronger-Better fit-Increased Density-Polymerized at higher temp-Processed on cast, decreases shrinkage
Indications for implant assisted rpd
–Esthetics
–Oral hygiene
–Extensive ridge defects
–Financial limitations
–Extension base applications
Prefab post disadvantages
Fit…
Not as precise as cast post
Crown angulation…
No compensation ability
Antirotation…
Must be provided by additional means
Palatal throat form
House
McDermott classification
–A modification of the Kennedy Classification
–Indicates arch configuration, and natural tooth abutment location
Size of canal space for post
- ≤ 1/3 root width
- Uniformly thick root walls
Post dia principles
- In contrast to post length, increasing post diameter does not increase retention
- Thick posts weaken teeth
- Thin posts may distort
- Beware of variations in dentin thickness (esp. man molars) and curvatures
What can pt expect
SPEECH: encourage patient to practice
DISCOMFORT: tell the dentist
EATING: a learning process
SALIVA: may be excessive in the beginning
What is proper O reduction
1.5-2mm
How important is the amount of remaining coronal tooth structure?
Cervical tooth structure should be retained or the finish line should be extended cervically to engage 1 or 2 mm of tooth structure
recommended taper of preparation
Interim res requirements
- Pulpal protection
- Positional stability
- Occlusal function
- Easily cleaned
- Nonimpinging margins
- Strength and retention
- Esthetics
How important is post diameter?
Diameter should be controlled to preserve root structure
Post diameters should not exceed one third of root diameter at any location
Post tip diameter should usually be 1 mm or less
