Fixed Prosthodontics

Front 1

What are the three general principles of tooth preparation?

Back 1

- biologic
- mechanical
- esthetic

Front 2

What are the BIOLOGIC considerations for tooth preparation?

Back 2

1) Prevention of damage during tooth prep
- adjacent teeth
- soft tissues
- pulp (tempt, chemical, bacterial)

2) Conservation of Tooth Structure
- thickness of dentin inversely proportional to pulp response

3) Considerations affecting future dental health
- axial reduction
- overcontoured margins lead to ging. inflammation
- max overcontour is 1mm
- margin placement (supragingival best)
- margin adaptation (junction vulnerable to recurrent decay - cement dissolution, inherent roughness)
- occlusal reduction consideration (functional cusp bevel, 1.5 mm clearance, parallels triangular ridges)
- preventing tooth fractures / cuspal protection

Front 3

What are the justifications for placing a margin SUBGINGIVALLY?

Back 3

- caries
- restorations
- retention
- esthetics
- root sensitivity
- alteration of axial contour
- fracture
- erosion / abrasion

Front 4

What is the approximate height of the BIOLOGIC WIDTH?

Back 4

2.0 mm

Front 5

What is the height of the JUNCTIONAL EPITHELIUM?

Back 5

0.97mm

Front 6

What is the height of the CONNECTIVE TISSUE ATTACHMENT TO BONE?

Back 6

1.07mm

Front 7

BIOLOGIC WIDTH = ?

Back 7

Junctional epithelium + connective tissue attachment to bone

Front 8

What is the width of explorer tip?

Back 8

0.230 mm

Front 9

What is the average gap between CROWN and TOOTH?

Back 9

0.070mm

Front 10

What factors affect marginal adaptation?

Back 10

- marginal design
- cement thickness
- impression accuracy and lab procedures

Front 11

What is the regular range of cement thickness?

Back 11

25-50 microns

Front 12

What is the thickness of ZINC PHOSPHATE cement?

Back 12

25 microns

Front 13

What is the thickness of ZINC POLYCARBONATE and GIC cement?

Back 13

< 25 microns

Front 14

What is the thickness of COMPOSITE / ADHESIVE resins?

Back 14

> 25 microns

Front 15

What are the MECHANICAL CONSIDERATIONS for tooth preparation?

Back 15

RESISTANCE FORM - lateral forces displace restoration by rotation around gingival margin
RETENTION FORM - length, taper, circumference
FACTORS AFFECTING RETENTION - magnitude of the dislodging forces/ geometry

Front 16

What are the factors that affect RETENTION of a restoration?

Back 16

- magnitude of the dislodging forces (sticky foods, bruxer habits)
- Geometry of tooth preparation
- most cements non-adhesive

Front 17

What is the IDEAL taper?

Back 17

6-10 degrees TOC

Front 18

What is the ACTUAL TAPER that is usually achieved?

Back 18

12.2 - 27 degrees
10-20' practically

Front 19

What is the minimum height of prepared tooth for PREMOLAR?

Back 19

3mm minimum

Front 20

What is the minimum height of prepared tooth structure for MOLARS?

Back 20

4mm minimum

Front 21

What can be done for teeth that do not meet minimum prepared tooth height criteria?

Back 21

Modified with grooves / boxes

Front 22

What are some importants things in ESTHETIC CONSIDERATIONS?

Back 22

- Restoration type (metal, all ceramic, PFM)
- Margin design and location

Front 23

What is ANTE'S RULE?

Back 23

The combined pericemental area of the abutment teeth should be equal to or greater than the pericemental area of the teeth being replaced

Front 24

What are the two major problems that seriously impede fabrication of sound restorations?

Back 24

- poor impressions of the gingival margins (primarily due to lack of hemorrhage control)
- inadequate reduction of tooth structure

Front 25

PROBLEM: Poor impressions and hemorrhage.

Back 25

SOLUTION:
Poor impressions: Proper injecting technique should be learned.
Hemorrhage: Achieve hemostasis PRIOR to final packing.

Front 26

PROBLEM: Inadequate tooth reduction.

Back 26

Conservative treatment has already failed by the time a tooth requires a crown. If it's indicated it should be FULLY REDCUED consistent with the restoration being provided.

SOLUTION:
- determine amount of tooth reduction required for intended restoration
- use some form of depth guide to ensure sufficient reduction
- work in a prescribed logical sequence

Front 27

Describe the procedure of PACKING RETRACTION CORD:

Back 27

1) Remove all pre-packed cords prior to using infuser tip
2) Select diameter of cord that you estimate will fill the smallest most delicate area of the sulcus (usually #1)
3) Use one long cord for each prep
4) place the cord in a dappen dish/medicine cup containing Astringident solution
5) Allow to soak
6) Use infuser tip as directed - angle tip towards GINGIVA (not tooth) and gently rub sulcus while expressing solution
7) when bleeding stops, wash all coagulum off the tooth and out of sulcus
8) continue to use syringe and Astringident until sulcus can be vigorously washed with three-way syringe w/o bleeding
===============================
DO NOT PACK CORD UNTIL THIS DEGREE OF HEMORRHAGE CONTROL HAS BEEN ESTABLISHED
===============================
9) Begin packing where sulcular tissue is LEAST likely area to damaged i.e. palatal aspect of max. preps or deepest part of sulcus
10) Start packing at the end of the cord (not in the middle)
11) Pack the soaked cord once around the tooth in a deliberate manner so that ALL (not just portions) of the sulcus receives and is displaced by cord. *CRITICAL*
12) Use the extra length of cord to DOUBLE PACK and displace those areas of the sulcus not adequately displaced while avoiding those areas already adequately displaced by the single first layer of cord
13) Cut off any remaining excess length of cord leaving an unpacked tag at the end to aid removal
14) Wait approx. 5 min
15) Obtain bite records or allow the patient to take a break
16) Obtain bite records or allow the patient to take a break

Front 28

What are the steps for removing packing cord for PARTIAL COVERAGE RESTORATIONS?

Back 28

- rinse, dry, isolate, and take impression with cord in place
- remove cord after inspecting impression for accuracy

Front 29

What are the steps for removing packing cord for MULTIPLE PREPARATIONS?

Back 29

TECHNIQUE 1
-------------------
Pull cord, rinse, dry, isolate.
If any bleeding occurs when cord is pulled, reenter sulcus with syringe and infuser tip until hemorrhage is controlled, then rinse, dry, isolate, and take impression

TECHNIQUE 2
----------------------
Prior to pulling the retraction cord, wash and thoroughly dry the ENTIRE ARHC, re-isolate the preparation area, and specifically dry the sulci of the prepared tooth (including cord).

Front 30

What are the steps for removing packing cord for MULTIPLE ADJACENT RESTORATIONS?

Back 30

- easier to pull all of the cords prior to injeting the impression material

Front 31

What tooth should you start injecting impression material into if you were working on multiple restorations?

Back 31

Disto-lingual line angle of the most distal preparation, into or just barely above the sulcus touching both prepared tooth and distal approximating tooth.

Front 32

TRUE or FALSE: Impression material should be expressed into the sulcus AHEAD of the injection tip.

Back 32

TRUE: always keep impression material flowing ahead of tip

Front 33

Identify the type of margin that [1] is:

Back 33

FEATHER EDGE

Front 34

Identify the type of margin that [2] is:

Back 34

CHISEL / KNIFE EDGE

Front 35

Identify the type of margin that [3] is:

Back 35

BEVEL SLOPED SHOULDER
(X) DEGREE SHOULDER

Front 36

Identify the type of margin that [4] is:

Back 36

CHAMFER

Front 37

Identify the type of margin that [5] is:

Back 37

DEEP CHAMFER

Front 38

Identify the type of margin that [6] is:

Back 38

SHALLOW/LONG CHAMFER

Front 39

Identify the type of margin that [7] is:

Back 39

ROUNDED SHOULDER

Front 40

Identify the type of margin that [8] is:

Back 40

SQUARE SHOULDER

Front 41

Identify the type of margin that [9] and [10] is:

Back 41

BEVELED CHAMFER and BEVELED SHOULDER

Front 42

Which margin has the BEST closing angle configuration?

Back 42

Feather edge

Front 43

What are generally the most advocated margin designs?

Back 43

- Deep chamfer
- Shoulder
- Beveled shoulder

Front 44

What are some "tests" to check whether a margin can be metal or whether it should be all-porcelain?

Back 44

- probe the sulcus and see if metal of probe is visible through tissue, awkward to inset, or causing noticeable blanching

Front 45

What depth of sulcus will easily allow a metal collar?

Back 45

3mm sulcus

Front 46

OUTLINE THE ACCEPTABLENESS FOR A PFM TOOTH PREPARATION:

Back 46

INCISAL REDUCTION
-------------------------------
straight and uniform, 2.0mm
may be bevelled lingually

LINGUAL REDUCTION
------------------------------
Clearance with lower incisors, 1.0 - 1.5 mm
Lingual fossa slightly concave
Lingual axial wall, 1.5 mm tall

AXIAL REDUCTION
---------------------------
Follows contour of original tooth
1.25 mm gingival
Lingual 0.3-0.7mm at gingival
Proximal 1.25mm (as viewed from facial)

DRAW AND TAPER
--------------------------
10 degrees mesiodistal / 20 degrees acceptable
Able to visualize all walls
Draw follows long axis of tooth

GINGIVAL EXTENSIONS
---------------------------------
0.2-0.5mm above tissue

PROXIMAL GINGIVAL CLEARANCE
--------------------------------------------
0.5mm clearance

MARGIN DEPTH / FORM
------------------------------------
Deep Chamfer (1.0-1.25mm wide)
Interproximal transitions
Chamfer on lingual (0.3-0.7mm)

Front 47

What are the biologic requirements for a PROVISIONAL?

Back 47

PULPAL PROTECTION - must seal and insulate the prepared tooth
MAINTAIN PERIO HEALTH - facilitate plaque removal, marginal fit, contour, and smooth
OCCLUSAL STABILITY
- maintain proper contacts with adjacent and opposing teeth
PREVENTION OF ENAMEL FRACTURE
- esp partial coverage
REMOVAL FOR RE-USE
DISPLACEMENT - prevented by proper tooth prep and well adapted internal aspects
ESTHETIC - diagnostic provisional

Front 48

What materials are available for making provisionals?

Back 48

- PMMA self cure (Alike)
- PMMA light cure (Unifast)
- BisGMA composite (ProTemp, Integrity)
- PEMA
- Radica

Front 49

What are the ADVANTAGES / DISADVANTAGES of PMMA materials?

Back 49

ALIKE
---------
ADV: cost, strength, easy to repair/modify
DIS: odour, exothermic, shrinkage

Front 50

What are the ADVANTAGES / DIS of INTEGRITY?

Back 50

ADV: no shrinkage, easy of use, esthetic
DIS: cost, difficult to repair or add to, brittle

Front 51

What are the different methods for making a provisional?

Back 51

DIRECT TECHNIQUE
INDIRECT TECHNIQUE
INDIRECT-DIRECT TECHNIQUE (shell-reline: multiple teeth/bridges)

Front 52

What are the ADV/DIS of DIRECT PROVISIONAL TECHNIQUE?

Back 52

ADV:
- quick and easy for single restoration
- less laboratory preparation

DIS:
- potential thermal trauma
- potential chemical trauma
- potential for marginal distortion with shrinkage
- more chairside time

Front 53

What are some methods of MINIMIZING HEAT TRANSFER to the pulp when making a DIRECT PROVISIONAL?

Back 53

1) In Situ
- complete polymerization occurs intraorally on the prepared tooth. Upon initial polymerization the acrylic is cooled with air/water syringe. ADV: less distortion, best marginal fit, DIS: high potential to lock into adjacent proximal undercuts

2) REMOVAL - upon initial polymer, remove temp, and place into WARM water to complete polymerization ADV: no potential to lock on; DIS: decreases marginal fit if removed early

3) ON/OFF - upon initial polym, lift provisional, flush with A/W, replace, and repeat until fully polymerized. ADV: no potential to lock on; DIS: most distortion and highest marginal discrepancy

Front 54

What is DR.T's preferred sequence of tooth prep?

Back 54

- occlusal bulk reduction
- buccal bulk
- lingual bulk
- proximal
- smooth axial surfaces and margins
- extend margins if needed

Front 55

What are some COMMON ERRORS in tooth preparation?

Back 55

- not using new diamonds
- insufficient reduction
- insufficient margin depth / geometry
- lip at margin- check with explorer
- grazing adjacent tooth

Front 56

What are some COMMON ERRORS in provisionalization?

Back 56

- starting too late
- under-contoured facially/ lingually
- short margins
- over-contoured
- under-polished (rough surface)

Front 57

Who said "The goal of prosthodontics is not only the meticulous replacement of that which is missing, but the preservation of that which remains."?

Back 57

M.M. Devan

Front 58

What are some patient assessment tools used in treatment planning?

Back 58

- patient interview and history
- clinical examination
- radiographic examination
- mounted models

Front 59

What are some findings that may indicate the need for periodontal treatment in conjunction with or prior to fixed prosthodontic therapy?

Back 59

- pocket depth excess of 3.0mm
- furcation involvement
- deviation of normal colour, contour, texture of gingiva
- marginal exudate
- less than 2.0mm of attached gingiva present
- muscle or frenal pulls
- moderate-severe recession

Front 60

From a prostho standpoint, what are the goals of perio treatment of a full coverage restoration?

Back 60

1) restoration of periodontium to optimal health
2) to create an environment that the patient can maintain

Front 61

What conditions can cause PDL irritatio?

Back 61

- tooth movement due to prosthesis or occlusion
- tooth or restoration in traumatic occlusion
- acute pulpitis
- gingivitis or periodontitis
- cracked tooth

Front 62

TRUE or FALSE: All endo treated posterior teeth should be crown?

Back 62

TRUE

Front 63

What are some important RADIOGRAPHIC SURVEY evaluations?

Back 63

- Evaluate existing restorations (proximal contours, margins defective, recurrent decay)
- Endo teeth (adequacy of fill, radiolucency in apical areas)
- root length, size, form
- Crown/Root ratio

Front 64

What is the purpose of having MOUNTED CASTS?

Back 64

- Allows superior visualization (extruded, rotated, malposed teeth, defective restorations, shape of tuberosities, location of frenal attachments, available interarch space)
- Allows for a detailed occlusal analysis
- Patient education and in tx plan presentation
- Diagnostic casts are permanent record (medico-legal)
- essential for tx planning in prostho
- Occlusion can be evaluated (traumatic, wear)
- occlusal interferences
- occlusal plane considerations
-

Front 65

What is the purpose of a FACEBOW TRANSFER?

Back 65

- to relate condylar components of articular to the patient in an anatomic manner

Front 66

What are some methods of correcting occlusal plane disruptions?

Back 66

- orthodontic repositioning
- enameloplasty
------------------
if a tooth requires more than 2mm of enameloplasty then a CROWN is indicated

Front 67

What are the INDICATIONS for treatment with a SINGLE FIXED FULL COVERAGE RESTORATION?

Back 67

- extensively restored tooth
- fractured cusps or crowns
- endo treated teeth (posterior mainly)
- esthetics (colour, contour, etc)
- Loss of tooth structure through erosion, abrasion
- Tooth wear (evaluate VDO, habits)
- Occlusal plane correction
- Replacement of existing inadequate full coverage restorations
- Implant prosthodontics

Front 68

What are some options for PARTIALLY EDENTULOUS patients?

Back 68

- fixed partial denture
- removeable partial denture
- implant supported or retained restoration
- complete denture
- removeable partial denture
- complete overdenture

Front 69

What should be presented to a patient?

Back 69

- Present no more than 3 options
- Cost/Time
- Expected prognosis
- Adv/Disadvantages

Front 70

What are the features of an ACCEPTABLE IMPRESSION?

Back 70

1. Prepared tooth and margins recorded
2. TOoth structure BEYOND MARGINS recorded
3. Adjacent teeth/tissues recorded
4. No bubbles, tears, imperfections

Front 71

What are the different types of cords?

Back 71

TWISTED: plain cotton, multiple strands, easily compressed, can fray
BRAIDED: keep shape, not compressed, little adhesion to tissue, do not fray
KNITTED: absorb more chemicals, tend to rebound in sulcus, adheres to tissue
RINGS: no cutting required, need multiple sizes
- ring form

Front 72

What are the two most commonly used medicaments?

Back 72

HEMODENT (Aluminum chloride 5%, 25%)
ASTRINGIDENT (Ferric sulfate 13.3%)

Front 73

What are the signs of EPINEPHRINE SYNDROME?

Back 73

SIGNS:
- increased HR
- increased BP
- increased RESP

SYMPTOMS:
- headache
- dizziness
- tremor
- fear
- nervousness

Front 74

What are the properties of HEMODENT (5% AlCl)

Back 74

- minimal tissue damage
- 10 minutes
- routine use
- no systemic effects
- milder
- does not stain tooth

Front 75

What are the properties of FERRIC SULFATE?

Back 75

- minimal tissue damage
- 3 minutes recommended
- with epinephrine
- directly against cut tissue
- temporary discoloration of tissues

Front 76

How long does discoloration of tissues from ASTRINGIDENT last?

Back 76

1-2 days

Front 77

Why is VISCOSTAT preferred?

Back 77

20% Ferric sulfate
- less acidic
- does not remove smear layer from prepared tooth

Front 78

How much recession generally occurs from retraction cord use?

Back 78

Minimal - 0.1mm

Front 79

What are the INDICATIONS for TWO CORD TECHNIQUE?

Back 79

- deep sulcus
- multiple teeth
- hemostasis
- fibrous gingiva
- can be used routinely

Front 80

What are the general choices for FIRST and 2nd CORD in 2-cord technique?

Back 80

FIRST: #000 or 00
SECOND: #0, 1, 2 cord

Front 81

TRUE or FALSE: First cord in 2-CORD tEchnique should be soaked in hemostatic agent of choice.

Back 81

FALSE - soak in water

Front 82

What are the indications for LESS RETRACTION TIME?

Back 82

- shallow sulcus
- thin fragile marginal tissue
- critically esthetic zones
- larger cords
- more cords
- more aggressive medicaments
- traumatized tissue
- 2nd/ 3rd retraction

Front 83

What are the indications for MORE RETRACTION TIME?

Back 83

- deep preparation
- hemorrhage prone
- fibrous resistant gingival tissue
- non-esthetic zones
- smaller cords
- fewer cords
- milder medicaments (hemodent)

Front 84

What are the requirements of an impression?

Back 84

- Contours of the prepared teeth, including all cavosurface margins and some submarginal area should be recorded
- occlusal surfaces of all unprepared teeth should be accurately recorded
- soft tissues of edentulous areas should be recorded to aid in developing pontic contours
- impression material should be free of voids in critical areas, no air trapped between injection material and tray material

Front 85

What should be checked PRIOR to restoration try-in appointment?

Back 85

EVALUATED ON ARTICULATOR FOR:
- marginal adaptation
- proximal / occlusal contours
- occlusal form
- axial contours
- tissue relationship / contact of pontics
- stability on die
- surface finish
- porcelain shades verified against tab
- gross deficiencies should be corrected prior to appt.

Front 86

What is the sequence of steps to TRY-IN / ADJUST fixed restorations?

Back 86

1) LOCAL ANAESTHESIA
2) Remove provisional
3) Tissue management
4) Seat restoration fully
5) Confirm marginal accuracy
6) Check proximal contacts
7) Assess stability
8) Adjust occlusion
9) Assess axial contours
10) Finish and polish restoration

Front 87

You are trying in a crown but it does not seat completely, what do you do now?

Back 87

- Check interior of restoration or the preparation surface for cement or other debris
- if no debris present, then check the interior of the restoration for positive blebs that may prevent seating
- remove blebs with HS ROUND BUR
- re-seat
- check proximal contacts for excessive pressure with floss while seating restoration with finger pressure (patient may inform you of tightness)
- adjust proximal contacts with diamond and/or green stone
- evaluate for axial wall bindind
- use FitChecker placed in restoration and seated onto prep, binding shows of axial walls
- adjust tight areas with HS Round bur (occlusal) or diamond (axial)
- at this stage call instructor. May need to be remade

Front 88

How does one correct UNDEREXTENDED or OPEN MARGINAL DISCREPANCIES?

Back 88

- must be re-made as these types can't be corrected
-

Front 89

What is the thickness of BLUE MYNOL?

Back 89

60-90 microns

Front 90

What is the thickness of ARTICULATING FOIL?

Back 90

8 microns

Front 91

What is the thickness of SHIMSTOCK FOIL?

Back 91

8 microns

Front 92

Where should CENTRIC CONTACTS be located?

Back 92

- Centric fossae
- Marginal ridges
- Cusp tips

ELIMINATE ANY CONTACTS ON INCLINES

Front 93

TRUE or FALSE: There should be no eccentric contacts present on posterior restorations.

Back 93

TRUE

Front 94

No overcontouring should be apparent in the gingival 1/3 of the restoration.

Back 94

t

Front 95

TRUE or FALSE: Core may serve as an interim restoration prior to crown fabrication.

Back 95

TRUE

Front 96

What are the ADVANTAGES of a TWO STEP APPROACH to RESTORATION OF ENDO TREATED TEETH?

Back 96

1) Post-core foundation restores the integrity of the pulpless tooth as a single unit, rendering it independent of the restoration that covers it
2) Changes can be made in the restoration without disturbing the main body of the tooth, such as removal of a single unit restoration for the purpose utilizing it as an abutment for a fixed bridge
3) The fit of the margins of the coronal restoration is independent of the post-core and its fit
4) It is possible to parallel abutment teeth in a fixed bridge more effectively

Front 97

What are the FOUR FUNDAMENTAL FACTORS INFLUENCING THE CHOICE OF FOUNDATION?

Back 97

THE CONDITION OF THE TOOTH
- amount of intact coronal tooth structure is most influential factor determining the foundation type
- much or all coronal structure is missing then foundation with max resistance and retention recommended

THE PURPOSE FOR WHICH THE TOOTH IS USED
- single unit vs bridge abutment?

OCCLUSION / OCCLUSAL HABITS
- no occlusal contact, potential for function low, minimal restorative needed
- if subject to much occlusal loading, bruxism, etc then it should be protected

THE ROOT/CANAL MORPHOLOGY
- tooth with narrow tortuous canals may not be possible to negotiate and may be treated conservatively with a short post, auxillary pins, or bonded core

Front 98

What are the THREE MAIN TYPES OF FOUNDATIONS and what are they used for?

Back 98

CUSTOM CAST POST-CORE
--------------------------------------
- incisors, canines, bicuspids become extremely weakened from access opening for endo, almost always require replacement of coronal tooth structure with a cast post-core.
- for most single rooted teeth because of increased strength of the one-piece castings and its resistance to rotation
- direct / indirect pattern of internal anatomy of the tooth
- preparation limited to removal of undercuts and placement of anti-rotational device

PREFABRICATED POST AND DIRECT CORE
----------------------------------------------------------
- direct restorative material is adapted to the post and tooth to form the core
- lower time involved
- lower cost
- potential to perforate the lateral walls of the apical portion of the root

ALL AMALGAM FOUNDATION
------------------------------------------
- coronal/radicular foundation technique using amalgam only is advocated for use in multi-rooted teeth
-

Front 99

What is the method of choice for CAST-POST CORES of POSTERIOR TEETH?

Back 99

Single cast core portion with imbedded "sliding" parallel sided posts

Front 100

What is the general guideline for whether you decide to do PARA-POST-CORE on posterior tooth?

Back 100

- one post for every missing 1/3 of total pulp chamber axial wall surface to a maximum of 2 posts
- molars missing greater than 2/3 of pulp chamber should be treated with CPC

Front 101

In general, endo treated teeth should have a post in what situations?

Back 101

- when tooth requires a crown
- when tooth has had previous caries
- restorations or fractures which have weakened remaining tooth structure
- greater functional demands are required of the tooth
- large canals / thin walls present in young teeth

Front 102

What are the steps for TAPERED CAST-POST-CORE PREPARATION?

Back 102

1) RCT must be properly done (Radiograph) and asymptomatic
2) Remove all previous restorations, caries, pulp chamber fill
3) Prepare margins on sound tooth structure to proper depth of reduction for crown
4) Remove all liable (unsound) tooth structure. Require 1/2mm minimum between internal and external preparation
5) Need 2mm minimum O-G clearance for bulk of core. This is in addition to occlusal reduction requirements for the crown.
6) Prepare positive occlusal seat. No bibevel.
7) Goal is to prepare maximum length of canal (desired 10mm) but must not disturb apical 4-5 mm of fill and seal
8) initially remove GP to within 1-2 mm of desired length
9) Start GP removal with #4 Gates-Glidden bur for the first 3mm, #3 GG for the next 3mm, and #2 GG for the remainder. Smaller canals may require smaller Gate-Glidden or shorter steps.
10) Verify the preparation length and remaining fill with radiograph
11) Adjust for remaining post length to desired length
12) Smooth lateral walls and impart gentle taper with tapered diamond in slow speed friction grip contra-angle
13) Moderate to large undercuts are to be blocked out. Smaller undercuts can be removed by preparation, but remember we should preserve as much tooth structure as possible
14) If canal preparation is near round include an anti-rotational notch in the widest axial wall
15) Round sharp line angles (canal-occlusal seat)

Front 103

What are the steps for PARAPOST PREPARATION?

Back 103

1) RCT must be properly done (radiograph) and asymptomatic
2) Remove all previous restorations, caries, pulp chamber fill
3) Prepare margins on sound tooth structure to proper depth of reduction for crown
4) remove all liable (unsound) tooth structure. Require 1/2mm min between external and internal preparation
5) Need 2mm minimum O-G clearance for bulk of core. This is in addition to occlusal reduction requirements for the crown.
6) Prepare positive occlusal seat. No bibevel.
7) Goal is prepare maximum length of canal (desire 10mm) but must not disturb apical 4-5mm of fill and seal
8) Initially remove GP to within 1-2mm of desired length
9) Start GP removal with #4 Gates-Glidden bur for the first 3mm, #3 GG for the next 3 mm and #2 GG for the remainder. Smaller canals may require smaller Gates-Glidden or shorter steps.
10) Start canal preparation with smallest Peeso-Reemer and/or pre-fabricated drill size and prepare to 1-2mm of desired length
11) Verify the preparation length and remaining fill with radiograph with post in place
12) Adjust for remaining post length to desired
13) Proper width of preparation has been achieved when 1/2-2/3 the apical length of the post has been prepared parallel and the post is relatively stable. Increase drill diameter and post diameter until stability is achieved, but be aware of remaining tooth structure and possibility of perforation.
14) Leave all undercuts
15) Place anti-rotational notch in the widest axial wall if coronal portion of canal is circular
16) Round sharp line angles (canal-occlusal seat)

Front 104

What are the steps of making PARALLEL PREFAB POST and DIRECT CORE?

Back 104

1) Prepare post space as in PARAPOST
2) Shorten prefabricated post from apical end prior to cementation so that retentive portion of coronal portion of post remains within core contours
3) Cement post
4) Keep cement out of anti-rotational notch and coronal 2mm of canal prep
5) Place core material into 2mm of canal prep and adapt to post
6) Prepare core

Front 105

WHat are the steps in TEMPORARY FABRICATION FOR CAST POST CORE?

Back 105

1) Place cotton pellet so coronal 5mm of canal available
2) Lubricate canal slightly (saliva, die-sep, vaseline)
3) Bead brush temporary acrylic into canal to occlusal seat
4) Fill vacuum template matrix, polycarboxylate crown, shell form with acrylic
5) Seat matrix onto preparation
6) Allow to fully seat
7) Remove, inspect for detail
8) Reseat, adjust to remove functional contacts (keep CO)
9) Trim and polish
10) Replace cotton pellet (cement barrier)
11) Cement temporary

Front 106

Whats the rationale for TEMPORARY?

Back 106

- prevent drifting and over-eruption of teeth
- esthetics
- function

Front 107

What are the INDICATIONS for DIRECT PATTERN TECHNIQUE for CPC?

Back 107

- difficult core contours
- custom fabrication to previous crown

Front 108

What are the ADVANTAGES of DIRECT PATTERN TECHNIQUE FOR CPC?

Back 108

- less laboratory time
- cost
- full control of core shape and size

Front 109

What are the INDICATIONS for INDIRECT (IMPRESSION) TECHNIQUE for CAST POST CORE?

Back 109

- large undercuts, undercuts which can't be blocked out
- multiple preparations
- divergent canals

ADV: Less chairside time

Front 110

What must be determied to ensure that an endodontically treated tooth is ready for subsequent restorative treatment?

Back 110

- good apical seal
- no sensitivity to pressure
- no exudate
- no fistula
- no apical sensitivity
- no active inflammation

Front 111

What six features must be incorporated into the tooth preparation for a CAST POST CORE?

Back 111

- apical seal
- minimal enlargement
- length
- stop
- anti-rotation
- margin extension

Front 112

Label the following:

Back 112

1. Apical seal (4-5mm)
2. Minimum canal enlargement (no undercuts remaining)
3. adequate post length
4. positive horizontal stop (to minimize wedging)
5. vertical wall to prevent rotation
6. externsion of the final restoration margin onto sound tooth structure

Front 113

Discuss 5 variables that have an impact on retention form for CPC's?

Back 113

1. Preparation geometry

2. Post length
- should be as long as possible without jeopardizing the apical seal or strength or integrity of remaining tooth structure
- or 2/3 root length

3. Post diameter
- increase diameter increase retention
- do not exceed ONE THIRD of cross-sectional root diameter

4. Post-surface texture
- serrated or roughened are more retentive

5. Luting agent

Front 114

How is an interim restoration fabricated for a mandibular second premolar that has been prepared for a CPC?

Back 114

1. Place piece of wire in the post space, to avoid root fracture it must extend passively to end of post space. Mounted stone can be used to taper the wire if binding occurs

2. Mark wire with pencil at the mouth of post space, then at point slightly occlusal to this mark use the pliers to make a 180-degree wire bend

3. Lubricate the tooth and surrounding soft tissues with petroleum. Paper points are convenient for this.

4. Fill the ESF with interim resin (poly methacylate recommended)

5. When the resin loses its surface gloss, place wire in the post space and seat the ESF over it. Precautions must be taken to protect the patient from swallowing or aspirating the wire.

6. Remove the ESF while the resin is still rubbery (after about 2-2.5 min. Stage of polym should be monitored. If resin is allowed to become rigid and lock into undercut surfaces within the post preparation, removing it and wire will be time consuming and risk restorability of the tooth.

7. Mark the margins with a pencil and trim and contour the restoration with disks or straight handpiece carbide burs

8. Evaluate the restoration in the mouth. Adjust as necessary

9. Polish, clean, and cement restoration

Front 115

What would be the outcome of placing the maring too deep in the sulcus?

Back 115

Possibility of biologic width violation, chronic gingival inflammation

Front 116

Prepared cervical margin should follow what?

Back 116

Scalloped anatomy of alveolar bone, attachment, and gingival tissues

Front 117

What is the CRITERIA FOR MARGIN SELECTION?

Back 117

1) Selected margin must provide a predictable level of marginal integrity
2) minimize plaque accumulation and selected margin must present smooth materials to the gingival sulcus
3) in some situations must provide acceptable aesthetics

Front 118

What are some problems that can result from improper preparation and placement of cervical margins?

Back 118

- biologic width violation
- metal margins showing through thin gingiva
- recession exposing tooth/rest surface
- opacity in cervical third of restoration
- roughness of cervical margin: contributes to plaque accumulation

Front 119

List all of the margins that are acceptable for METAL CERAMIC CROWNS:

Back 119

- knife-edge
- chamfer
- shoulder
- buttjoint
- beveled shoulder
- slant shoulder
- disappearing margin

Front 120

What is the IDEAL margin for a PFM?

Back 120

SHOULDER and any variation of it

Front 121

How wide should the collar of a shoulder for PFM be?

Back 121

1mm or more

Front 122

What is the IDEAL margin for a PFM with metal collar/disappearing margin?

Back 122

SLANTED SHOULDER

Front 123

Why is a bevel margin better for PFMs?

Back 123

Substantial metal collar which provides best initial fit before firing porcelain, this fit is maintained over all ceramic firing cycles.
Can be highly polished (smoothness for biocompatibility)
Problem is aesthetics

Front 124

What is important when choosing SHOULDER BEVEL margin?

Back 124

- metal display inherent
- patient should sign consent prior to utilizing this margin design

Front 125

If AESTHETICS are important what are some design options for a crown?

Back 125

1) USE ALL CERAMIC CROWN
- shoulder margin with rounded internal line angle
- 90 degrees to external angle of labial/buccal surface
- 1.2-1.5 mm depth for optimum aesthetics
- if SLANT in margin is present, tensile forces occur in function, HALF-MOON fractures in the cervical area

2) METAL-CERAMIC RESTORATION
- Porcelain labial margin (shoulder)
- disappearing margin
- inherent roughness of disappearing margin
- patients with low smile line, slant shoulder with metal collar should be considered
- if smile exposes cervical portion of restoration, disappearing is the choice
- shoulder margin carried INTERPROXIMALLY to proximal lingual line angle.. 1.2 mm
-
3) EXTEND METAL FRAMEWORK TO AXIO-GINGIVAL LINE ANGLE
- shorten metal framework and terminate it 1mm from shoulder margin (metal cutback)

Front 126

What is the MOST COMMONLY used shade matching method?

Back 126

VISUAL- vitapan,

Front 127

ALL CERAMIC crown usually has what layers?

Back 127

- core material
- body porcelain
- incisal porcelain

Front 128

TRUE or FALSE: Veneer preparation was initially done with minimal or no preparation.

Back 128

TRUE

Front 129

What is the main reason for VENEER PREPARATION?

Back 129

- exposure of enamel rods for superior bond strengths

Front 130

What are the three types of INCISAL PREP for veneer?

Back 130

- window
- overlapped incisal edge
- feathered incisal

Front 131

What can one do during VENEER IMPRESSION to help with die separation?

Back 131

Place clear matrices interproximall

Front 132

What materials are used for VENEER?

Back 132

FELDSPATHIC PORCELAIN
- platinum foil tech
- refractory die technique

EMPRESS/E-MAX
- CAD or pressed

Front 133

What is the IDEAL preparation for bonding VENEER?

Back 133

- etching inner surface with HYDROFLUORIC ACID and SILANATION = higher bond strength of luting composite to porcelain than bond strength of luting composite to enamel

Front 134

If there is contamination of the surface with saliva during bonding a VENEER what should you do?

Back 134

Re-etch with 37% phosphoric acid

Front 135

What is the preferred method for LUTING veneer?

Back 135

- light curing composite
- longer working time
- color stability is superior
- Thickness of greater than 0.7mm may require DUAL CURE cement
- place clear matrices / wedges during cementation

Front 136

What is the typical failure rate of VENEER (porcelain)?

Back 136

5% after 5 years

Front 137

What are the ADV / DISADV of CERAMIC INLAYS/ONLAYS?

Back 137

ADVANTAGES:
- improved aesthetics
- good durability and strength
- eliminates any shrinkage during curing

DISADVANTAGES
- possible wear of luting agent
- possible wear of opposing teeth
- luting gaps are often wider than ideal

Front 138

Generally, what is the 10 year survival rate of CERAMIC ONLAYS/INLAYS?

Back 138

90%

Front 139

The tooth gets its colour primarily from what?

Back 139

DENTIN

Front 140

What are the three components of colour?

Back 140

HUE
CHROMA
VALUE

Front 141

Arrange which 1/3 of the tooth has MOST to LEAST amount of colourL

Back 141

MIDDLE THIRD > cervical third > incisal

Front 142

Define METAMERISM:

Back 142

two colours that appear to be a match under a given lighting condition but have differenet spectral reflectance are called metamers

Front 143

How can the problem of metamerism be avoided?

Back 143

- selecting a shade and confirming it under a variety of lighting conditions
- providing sufficient bulk of porcelain over opaque
- minimizing surface modifications with external stains

Front 144

What is the SEQUENCE of shade selection?

Back 144

HUE -> chroma -> value -> metameric effect

Front 145

What HUE is in the ABCD shade guide?

Back 145

A- brownish
B- yellowish
C- grey
D- reddish

Front 146

Which tooth is the most saturated in colour?

Back 146

CANINE - use it to determine HUE

Front 147

The SQUINT test is useful for what?

Back 147

Determining VALUE!

Front 148

How does one use the SQUINT test?

Back 148

Squint until whichever disappears from sight first - tooth or shade tab. One that fades FIRST has lower value.

Front 149

How can one DECREASE brightness of a restoration?

Back 149

- increasing depth of translucency
- surface modification

Front 150

Which light is the most important for revealing metameric changes in colours?

Back 150

SUBDUED TUNGSTEN LIGHT

Front 151

What are the GENERAL PRINCIPLES in shade guide selection?

Back 151

1. Use the shade guide that matches the type of porcelain to be used.
2. Patient should be viewed at eye level
3. Shade comparison should be made under different lighting conditions. Use full spectrum light if possible
4. Should be made at the START of the appointment
5. Teeth should be clean, remove dry calculus and stain by prophylaxis
6. Distracting, brightly coloured lipstick should be removed. Brightly coloured clothing should be draped.
7. Make shade selection initially with tooth and guide dry, then finally confirm under wet conditions. Place guide under lip, close to, and with same illumination as the tooth
8. Shade selections should be made QUICKLY to avoid fatigue of eyes. Rest eyes on grey surface to balance colour receptors.
9. Concentrate on MIDDLE THIRD of the tooth
10. Match the value, ideally use separate guide for this
11. MAKE A DRAWING of tooth for prescription
12.

Front 152

What happens to tooth colour when they get dry?

Back 152

value INCREASES

Front 153

Which receptors in the eyes allow us to see colour?

Back 153

CONES

Front 154

What are the principle goals of DENTAL CEMENTS?

Back 154

- retention
- sealing (elimination of microleakage)

Front 155

What are the ideal properties of DENTAL CEMENTS?

Back 155

WORKING TIME - adequate to allow proper mixing, loading and seating of crown
SETTING TIME - rapid set once in mouth after proper positioning
MANIPULATION - low technique sensitivity so that slight deviation of ideal condition or handling will not critically affect result, easy manipulation
FILM THICKNESS - less than 30 microns so that it does not affect tolerance to which we can fit our restorations
BONDING/ADHERENCE - bonding and/or adherence to tooth structure and restorative material
SOLUBILITY - low solubility in water, resistance to acid attack
HIGH COMPRESSIVE/TENSILE strength
THERMAL INSULATION - when used as a base, film thickness when used as luting agent too thin for thermal insulation
PULPAL RESPONSE - low, biocompatible, possible obtundant
FLUORIDE RELEASE - thought to be anticariogenic
COLOUR - tooth coloured and translucent cements desired for aesthetics with translucent restorations. Opaque easier for cleaning.
EASE OF CLEANING - adherence to tooth, soft tissue, and restoration impedes cement cleaning

Front 156

What are the mechanisms of action of dental cements?

Back 156

NON-ADHESIVE LUTING: retention to small undercuts on tooth/restoration surfaces from cutting
MICROMECHANICAL BONDING: retention to microscopic undercuts due to etching, hybridization, etc.

Front 157

What is the order of COMPRESSIVE/TENSILE STRENGTH (strongest to weakest) of dental cements?

Back 157

RESIN > resin reinforced GIC > GIC > Zinc phosphate > polycarb

[ RIGZP ]

Front 158

What is the order of BOND STRENGTH (strongest to weakest) of dental cements?

Back 158

RESIN > resin reinforced GIC > GIC > Polycarb > ZnP

[ RIGPZ ]

Front 159

What is the order of SOLUBILITY (LEAST to most) of dental cements?

Back 159

RESIN > PolyC > Resin-reinforced GIC > ZnP > GIC

[ RPIZG ]

Front 160

What is the order of FILM THICKNESS (SMALLEST to largest) of dental cements?

Back 160

RESIN REINFORCED GIC < GIC < ZnP < Resin

[ IGZR ]

Front 161

Post-cementation thermal sensitivity has been reported for which dental cements?

Back 161

ZnP and GIC (low pH at initial mixing)

Front 162

What is the composition of Zinc Phosphate cement?

Back 162

Zinc oxide + MgO
Phosphoric acid

Front 163

What are the ADV/DIS of Zinc Phosphate cement?

Back 163

ADV:
- long track record
- good physical properties with proper mixing
- predictable, high rigidity (MOE)
- easy to remove set material

DIS:
- no bond to tooth/resto
- incidence of tooth sensitivity
- increased microleakage compared to other cements

Front 164

FUJI PLUS is what kind of cement?

Back 164

Resin-modified GIC

Front 165

What TEMPORARY CEMENTS are there?

Back 165

ZINC OXIDE EUGENOL (TempBond)
- setting accelerated with moisture and temp
- effective seal
- decreased sensitivity
- sensitive effect on pulp
- dissolves when exposed in oral environment
- inhibits resin polymerization
- can decrease strength by mixing petroleum jelly (max 20%)

NON-EUGENOL ZINC OXIDE (Fregenol)
- no sedative effect on pulp
- compatible with resin material
- doesnt adhere to metal as well as ZOE

RESIN (TempBond Clear)
- good aesthetics
- higher strength and retention
- difficult to see excess
- may be difficult to remove
- use lubricant over comp cores/restorations

ZINC POLYCARBOXYLATE
- good for temp cementation of bridges, preps with poor retention, long term provisionals

Front 166

What is the purpose of QUARTZ in PFM?

Back 166

- stability by forming refractory skeleton

Front 167

What is the purpose of KOALIN in PFM?

Back 167

- sticky: holds the porcelain particles together during firing
- strongly opaque
- current porcelains use organic binders such as sugars/corn starch

Front 168

What is the composition fo DENTAL PORCELAINS?

Back 168

1) Feldspar
2) Quartz
3) Koalin (binder)
4) Fluxes
5) Coloring agents

Front 169

What are the COLORING AGENTS in PFM?

Back 169

Metallic oxides

Front 170

What is the purpose of FLUXES in PFM?

Back 170

- change in firing temperature or thermal coefficient of expansion

Front 171

What are some important PRE-OP ASSESSMENTS that should be made before making PFM?

Back 171

- level of incisal edge
- overlap / occlusion
- facial contours with adjacent tooth
- proximal contacts
- lingual wall height
-

Front 172

TRUE or FALSE: The amount of ferrule is more important than the length of post in reducing root?

Back 172

TRUE

Front 173

What are the two ways of removing GP from root canal?

Back 173

1) warmed endodontic plugger - eliminates possibility of damaging dentin
2) rotatry instruments - if GP is old and lost its thermoplasticity

Front 174

In short teeth, what is the absolute minimum that the POST length into canal can be

Back 174

3mm

Front 175

What are the steps in TRIAL INSERTION / CEMENTATION of post?

Back 175

1) inspect casting (blebs, ribbons)
2) Remove temporary, cement, cotton pellet, and debris from canal
3) Trial seat post, core casting w/o pressure
4) if binding first remove likely areas
5) reseat, if still binding, sandblasting and pressure area will appear burnished
6) passive seating with stability should be evident
7) longer parallel posts
8) clean and dry canal
9) Mix Zn Phosphate cement
10) Place cement into canal with lentula spiral
11) Place cement on post and insert into canal
12) Verify seating
13) Hold in place until cement is set

Front 176

What are the IDEAL core material properties?

Back 176

- adequate compressive strength
- flexural strength
- biocompatibility
- resistance to leakage
- ease of manipulation
- bonds to tooth structure
- thermal coefficient similar to tooth structure
- dimensional stability
- minimal water sorption
- inhibition of caries
- esthetics