Indirect Restorations: Midterm1 Flashcards
(170 cards)
1
Q
Advantages of indirect restorations (compared to directs )
A
● ○Better Material
■Improved mechanical & physical properties ■Improved durability, aesthetics, color stability
○Unlimited Control
■Easier to get ideal occlusion and contours
■Improved access and vision ■Less time and patient constraints
○Some materials can only be used indirectly ■Bridges etc
2
Q
Disadvantages of indirect restorations (compared to directs )
A
○Difficult to be minimally invasive
■Minimum amount of reduction required for chosen material
■Need to reduce more for path of insertion ■However, could argue that a well done indirect restoration may be more minimally invasive over the long term, if it needs less replacing etc
○More time/less convenience
■Generally multiple appointments
○Not easy to replace as compared to direct restorations
○More independent Steps
■More chance of screwing something up
■Also technician is involved (Another potential point of failure)
○Lab fees
○Cement is the weak link
■Direct materials require no intermediary in between the material and tooth ○Temporisation required
3
Q
- Cast gold restoration treatment planning today compared to yesterday.
A
●Back in the day gold was the only choice for crowns
●Less common nowadays
●Price of gold is increasing
●Earlier gold restorations had to be fixed with zinc phosphate cement , that reduced its efficiency . Nowadays , better cements like GIC and resin cements are used , so better prognosis .
4
Q
- Why are onlays better than inlays?
A
●Onlays are protective (Because they shoe all the cusps
) ●Inlays do not shoe any cusps, if too wide or deep or with sharp line angles- can cause tooth fracture under occlusal forces
5
Q
What’s the difference between an intra-coronal and an extra-coronal restoration?
A
●Intracoronal
○Gets retention & resistance from internal walls
○Does not shoe any cusps
●Extracoronal
○Gets retention & resistance from external walls
○Typically shoes all the cusps
○More protective than intracoronal
6
Q
What’s the definition of a “protective” restoration?
A
●Protective restoration
: ○Shoes all the cusps
○Prevents cuspal flexion
○Therefore prevents cuspal fracture
7
Q
- Generic preparation principles for indirect restorations
A
○Path of Insertion
■AKA ‘Draw
’ ■The path along which your restoration will slide in/out or on/off your preparation
■Usually perpendicular to the occlusal plane (Except Class Vs) ■Usually parallel to long axis of tooth (Except tipped teeth) ○Retention (Macro/Micromechanical)
■What you do to stop your restoration coming off the tooth ■Micromechanical retention is similar to the kind of retention you get with composite ■Improved with reduced taper ■No undercuts
○Space/Thickness ■Can’t be made very thin or the restoration will break
○Cavo-surface angles
○Resistance form
■Flat gingival floors
○Outline form & Extension for prevention
■MO inlay you need to break contact ○Internal Angles ■Big difference between a waxed up and milled preparation
■Milling machine has limitations
■Can’t have weird sharp interior angles
■Rounded angles always good
8
Q
Principles for indirect restorations: Path of Insertion
A
■AKA ‘Draw
’ ■The path along which your restoration will slide in/out or on/off your preparation
■Usually perpendicular to the occlusal plane (Except Class Vs) ■
Usually parallel to long axis of tooth (Except tipped teeth)
9
Q
Principles for indirect restorations: Retention (Macro/Micromechanical)
A
■What you do to stop your restoration coming off the tooth
■Micromechanical retention is similar to the kind of retention you get with composite
■Improved with reduced taper
■No undercuts
10
Q
Principles for indirect restorations: Space/Thickness
A
■Can’t be made very thin or the restoration will break
11
Q
Principles for indirect restorations: Resistance
A
■Flat gingival floors
12
Q
Principles for indirect restorations: Outline form
A
Outline form & Extension for prevention
■MO inlay you need to break contact
13
Q
Principles for indirect restorations: Internal Angles
A
■Big difference between a waxed up and milled preparation
■Milling machine has limitations
■Can’t have weird sharp interior angles
■Rounded angles always good
14
Q
●Factors for success of indirect restorations
A
○All weak cusps shoed ○Supragingival, maintainable margins ○Supra-CEJ margins ■Especially ceramics ○Intimate seating ■Means you need less cement ■Which means you are depending less n the weak link (The Cement) ○Durable material ■Hardness ■Strength ○Perfect Cement ○Acceptable aesthetics
15
Q
Adequate occlusal clearance / material thickness, why so important???
A
●Amount of space depends on:
○Material you’re using
■Type of material determines minimum depth & width
■Need a uniform thickness, appropriate for material
●Fracture/wear resistance
○If ceramic is too thin it will fracture
○If gold is too thin you will get wear through
●Esthetics
●Keep Lab tech/milling machine happy
Two most common complaints: ■Not enough reduction ■Unclear margins
●Minimally invasive dentistry
○Taking off too much will reduce retention and cause other problems
16
Q
Two most common complaints for indirect restorations
A
■Not enough reduction
■Unclear margins
17
Q
●Amount of space for indirect restorations depends on:
A
○Material you’re using
■Type of material determines minimum depth & width
■Need a uniform thickness, appropriate for material ●Fracture/wear resistance
○If ceramic is too thin it will fracture
○If gold is too thin you will get wear through
●Esthetics
18
Q
path of insertion/withdrawal.
A
●AKA ‘Line of Draw’ ●Most will have a path of insertion which is: ○Perpendicular to the plane of occlusion ○Parallel to the long axis of the tooth ●In 3-dimensions
19
Q
Path of insertion is also called——?
A
Line of Draw
20
Q
Line of draw is in 3-dimensions. T/F
A
T
21
Q
Retention form, divergence & convergence, vertical walls
A
●Preparation Height
○Long preparation better than short
○In inlays height refers to the internal walls
●Degree of Taper ○Sets of slightly divergent walls (In contrast to convergent walls in a crown prep) ○More taper = Less retention ○Less taper = More retention ○But NOT parallel ■Won’t be able to seat it
●Boxes, Grooves & Shoulders
○When you cannot get a lot of :
■Height
■Taper
●Sets of vertical walls
○Sometimes hard to find those sets of vertical walls in an inlay/onlay
○Will have to then depend on boxes, grooves etc
22
Q
Sealing
A
○How close your restoration is going to fit in your inlay preparation
○Closer fitting means less cement thickness
○The internal part of the crown or preparation are in intimate contact, cement thickness as small as possible or a seating as good as possible
23
Q
seating
A
○Refers to how close the margins fit
○If margins are well sealed the restoration will last longer
○The placement of bevel on the finish line margin creates better sealing (more acute the bevel, the better the sealing )
24
Q
Which has better seating and seating: cast gold or milled ceramic?
A
●Cast Gold vs Milled Ceramic
○Cast gold is better
○Because gold is Ductile
○Allows you to burnish the margins to get better sealing
○Metal resiliency leads to better seating
25
difference in “retention” for cast gold VS bonded ceramic.
For direct, we need macromechanical retention form like the tapered walls or the retention form of inlay, divergent for path of insertion
-the factors that contribute to the retention for a crown, inlay, onlay:
-- preparation height: more retention if the height is greater, more difficult to gain retention for the mandibular 2nd and 3rd molars that are usually very short
-- degree of taper: more parallel walls add more retention but perfect parallelism could produce an undercut that can’t be seen
-- boxes, grooves, shoulders
: -sets of vertical walls: hard to be found information onlays
26
factors that contribute to the retention for a crown, inlay, onlay
- preparation height: more retention if the height is greater, more difficult to gain retention for the mandibular 2nd and 3rd molars that are usually very short
- degree of taper: more parallel walls add more retention but perfect parallelism could produce an undercut that can’t be seen
- boxes, grooves, shoulders:
- sets of vertical walls: hard to be found information onlays
27
—— degrees is good for crowns and inlays
10 degrees is good for crowns and inlays
28
For ceramics why do we have to stay on enamel?
For ceramics we need micromechanical retention: we have to stay on enamel because ceramic restorations are bonded to the tooth using resin cement, etch prime and seal, supra CEJ and supragingival are better to stay on enamel
29
Can optical impressions be used for metallic restorations? Or just milled restorations?
Dr. McManama in his lecture: “Even if you send a conventional impression the lab can scan the dye on the model and use the milling technique and they can create gold, porcelain fused to metal crowns, zirconia, layered zirconia, they can do almost anything. With an in-office milling technology you limit yourself, you can’t do gold, etc., mostly ceramic restorations.”
30
Clear, distinct and readable margins: why so important for ANY indirect restoration?
● If a lab techs can’t read your margin, they won’t know where to put the margin on the restoration
● If the margin that comes back from the lab and doesn’t match the margins on the patient, the restoration won’t fit
● A bad impression could be due to a bad impression OR a bad prep
● The ability to read and evaluate impressions is critical (to avoid wasting time and money)
● You shouldn’t have to say “I think” it’s good, it should be obvious
● Need the margin to be perfectly READABLE…not just to you, but also to a lab tech! Importance - for better impression , visibility , protection of gingival tissue
31
15. Why must the outline form for a milled restoration have smooth transitions?
Because sharp angular transition cannot be milled due to the milling bur shapes
32
16. Why must a prep for a milled restoration NOT have sharp internal line & point angles?
-Machine will over-mill restoration; prep not same as milled restoration = problem -Rounded internal angles ensure passive insertion and seating and prevent fracture
33
Undercuts: Definition
An impediment to a smooth insertion and withdrawal of your restoration onto the preparation
34
Undercuts: how to “see” them
How to see
: ○Use Prepcheck where appropriate
○Align your line of sight along the path of insertion
```
■Old fashioned way (Although will have to use your mirror in mouth, so that the reflected view is along your path of insertion)
■Need to be able to see:
●Your whole preparation
●All the margins
— ■If you can’t, you have an undercut
```
35
Undercuts: two ways to remove them.
Two ways to remove
: ○Remove the undercut
○Block out the undercut
■If an internal dentinal undercut
■Use GIC
36
18. What are the four objectives of good tissue management (retraction)?
```
●Vertical Displacement
○Usually 0.5mm
●Lateral displacement
●Fully recoverable
●Hemostasis
```
○Blood will screw up your impression - No.1 thing you don’t want when getting an impression ○Hydrophobic impression materials don’t do well with blood
○Optical impression will interpret the blood as part of the prep
37
No.1 thing you don’t want when getting an impression
Blood
38
What is retraction cord treated with?
●Astringent
○Epinephrine
■Good Hemostasis
■Good Vasoconstriction
○Aluminium sulfate
■Good hemostasis
■Poor vasoconstriction
39
untreated cord?
●Untreated cord
| ○Only provides mechanical displacement ○Can buy it and dip it in your own astringent
40
How does retraction cord actually work?
●How it works
: ○The cord itself causes mechanical vertical and horizontal displacement of the gingiva
○The vasoconstrictor (astringent) causes the tissue to shrink, therefore also causing displacement
○This reveals more of the cervical region of the tooth
○Allows more accurate preparation and impressions of this area
41
What is blanching?
Blanching
○Pale appearance of tissue
○Due to vasoconstriction
42
What are some alternatives to cord?
●Alternatives
1. Gingival retraction clamp
■Cannot retract interproximal area
■Full recovery
2. Scalpel
■Too aggressive
■May not get full recovery
3.Electrosurgery
■Literally burning tissue away
■Was used decades ago
■May not get full recovery
4.Laser ablation
■Has replaced electrosurgery
■May not get full recovery
5.Rotary curettage
■Cutting the lining of the sulcus using a special diamond bur
■Not recommended
6.Retraction putties
■Material in a syringe that can be injected into the sulcus
■Rubbery-like material
43
Is retraction always needed?
No
○Unnecessary when:
■You have very supragingival margins
■When prep ends 1mm or more from the gingiva
44
Is there a difference in tissue retraction for optical and elastic impressions?
●Not really
●May be even more important for an optical impression because you don’t get the physical penetration that you get with a conventional impression material.
45
Two-Cord Technique: 1st cord
■First cord
●Narrow diameter (e.g. No. 0)
●Mild astringent
●Use epinephrine if safe for patient
●Aluminium sulfate if they have a dodgy medical history
●No ‘tail’ (i.e. should be completely buried and you should not be able to see it)
46
Two-Cord Technique: 2nd cord
■Second cord
●Slightly wider diameter
●Short ‘Tail’ (Allows you to remove it just before your impression)
47
steps for a “two cord” retraction technique
Technique
■Use Local anaesthetic
■Do rough supragingival preparation
■Place first retraction cord (Use a serrated cord packing instrument)
●Start off pretending its floss
●Tease it into the proximal surface
●Usually allows it to slide right into the proximal sulci ●Only place where your need it
●Push and tuck cord towards where you have already packed the cord ○This will prevent it from being pulled out
■Wait a couple of minutes for some retraction
■Prepare the finish line
■This allows you to:
●See better
●Avoid damaging the gingivae ○Need a dry field
■Use cotton rolls
■Saliva contamination:
●Dilutes the vasoconstrictor
●Cause the cord to float out of the sulcus
48
Advantages of 2 cord technique
○Retracts deeper than one cord technique ○Allows impression material flows into the gingival pocket created by the 2nd cord
○Increase chance of capturing a better margin ○The cord will keep the bleeding under control
49
Disadvantages of 2 cord technique
○Placement of the cord will cause some damage to the gingiva
○If you remove the cord just before your impression, bleeding will start
○This will affect the quality of your impression
50
4. What’s a tail?
●Excess/overlapping length of retraction cord
●Sticks out supragingivally on the buccal side
●Makes it easier for you to pull a cord out quickly, just before taking the impression
51
How long should cord stay in place?
7 mins to get optimum shrinkage of tissues, in a reasonably dry field free of saliva or blood
52
Should cord be Wet or dry?
● wetted to prevent it from sticking to tissues (google, he didn’t mention it)
● Wetted by astringent is the most preferable
53
Define a “perfect impression”….what should you look for?
-precise detail (accuracy)
-beyond the margins
-how many teeth?, at least the tooth prepped and the adjacent teeth, the more teeth in the model the
more accurate the articulation
-elastic and tough (high tear strength)
-dimensionally stable
54
Impression: Precise Detail
Precise Detail
○ AKA ‘Dimensional Accuracy’
○ i.e. any model made from your impression is an exact replica of the actual tooth
55
Impression: Dimensional Stability
Dimensionally stable: should not change shape once removed from the mouth
56
Impression: Elastic property
Be elastic enough to be able to remove the impression material from the
mouth without any distortion or deformation
57
Impression: Includes the appropriate number of teeth
Includes the appropriate number of teeth
○ Depends what you’re doing
○ More teeth = More accurate articulation between upper and lower
○ Don’t really need a full arch impression for a single tooth restoration
○ Need a full arch impression for multiple units and bridges
58
Impression: Dimensional Accuracy
Any model made from your impression should be an exact replica of the tooth
59
What is more important, dimensional stability or dimensional accuracy?
Dimensional accuracy is always more important . It gives you precise detail and an exact replica of the tooth you’re working on . Dimensional stability may not be as
important as accuracy but makes life easier .
○ Dimensional accuracy is important because if an impression is not accurate, the
anatomy of the preparation captured is incorrect no matter what. If the impression is
lack of dimensional stability but we pour it right away after impression is taken, we
could minimize the distortion and the impression is still relatively close to the true
detail of the prep.
60
Two reasons you should routinely use a dimensionally stable impression material.
● You don’t need to pour the impression up immediately
| ● You can pour it up multiple times from the same impression
61
Why is elasticity so important?
Allows you to remove the impression from the mouth without any distortion or
deformation
62
Name two types of impression materials that are BOTH accurate & stable.
- Polyether
| - Polyvinylsiloxane
63
Name two types of impression materials that are accurate but NOT stable.
- Polysulfide
| - Reversible hydrocolloid (Agar Agar)
64
Name one type of impression material that is neither accurate nor stable enough for final
impression
Hydrocolloid
○ Irreversible (Alginate)
○ Reversible
65
Why is it important to impress “beyond” the margin?
● Confirm Margin placement
| ● See the contours of the tooth beyond the margin
66
Stock tray
■ Most common/normal
■ Can use with both PVS (Polyvinylsiloxane) & Polyether
■ Can alter a plastic stock tray with a lathe if required
■ Comes in small, medium and large
■ Available in full arch/quadrant
67
Custom tray
■ Need a study model first
■ Use a spacer
■ Make a relatively loose fitting tray
■ Uses less impression material compared to a stock tray
■ NO border moulding (In contrast to remo)
● e.g. Should not go to vestibule or vibrating line
68
When to use a custom tray?
○ When a patient has an unusually-shaped mouth, and a stock tray just won’t fit
○ If you’re doing lots of teeth at the same time, such as for a large span bridge
○ If you’re cheap and want to use less impression material (but custom tray added extra
cost to the total fee… so it depends)
69
Full arch trays….pros
full-arch: Pros: every tooth in the mouth, easier to articulate and do occlusal adjustment , more
stable , less movement of impression material
70
Full arch trays….cons
Cons: more impression material used so more expensive , uncomfortable while seating and
removing tray , more gag , difficult to remove from undercut
71
Quadrant trays:pros
Pros: less material used so less
expensive , and more comfortable for the patient , less gag, saves material , can check anterior and
canine guidance in 2/3rd stock tray;
72
Quadrant trays: Cons
Cons: cannot fully evaluate the occlusion, excursive movement,
sometimes the occlusion is not very accurate
73
Quadrant trays:
from central to most posterior tooth of that quadrant,
74
The purpose of perforations in a tray
○ Retention
| ■ Prevents separation of impression from tray on removal from the mouth
75
When are perforations in trays most critical?
○ Most critical in stock trays and custom trays used for patients with teeth
○ Critical because it gives positive pressure while making impression and so the material makes it way into the tissue details
76
Why use masking tape on trays?
● Used to block perforations in impression trays
○ Maximize positive pressure
○ Helps impression material work its way into grooves, around prep and into sulci
○ Improves impression detail
● Stops excess material oozing out into the patient’s mouth, which may cause gagging
77
What is a 2/3 tray?
Dr. McManama’s favorite
● uses for:
○ Posterior single units
○ Adjacent single units
78
2/3 tray advantage
Advantages:
○ Allows you to save material
○ More comfortable for patient, less likely to gag
● Want all the anterior teeth including canines and all posterior teeth in the area you are
working in
○ Allows enough teeth to check lateral excursions and incisal guidance
79
Tray adhesives
● Place adhesive while waiting for anaesthetic to kick in, early in the appointment
● Important to use the right adhesive
○ i.e. use the right adhesive for the right impression material
○ Otherwise it won’t stick to the impression tray
● Thoroughly paint the tray with adhesive
○ So that you are absolutely certain that there won’t be any separation
● Can also use adhesive in a custom tray
80
Why do you want compression for crown impressions but not for denture impressions?
Because we need to force the impression material to go into the sulcus, occlusal grooves and intimate to prep margins
81
What three things are done simultaneously when using a triple tray?
● Bite registration
● Final impression of your preparation
● Counter arch impression
82
step-by-step techniques for using a triple tray.
● Try it in first to make sure it fits properly
○ Especially the bar connecting the buccal and lingual
● Stiff impression materials are best for a triple tray
○ Like polyether
● Extrude impression material on both mandibular and maxillary sides of the triple tray
● Remove the superficial cord if using a two-cord retraction cord technique
● Position the triple tray carefully
● Patient should occlude into MIP
● Check the contralateral side to make sure they are in MIP
● Patient cannot move until the material is set
83
What are the differences between bis-acryl and MMA temporary materials?
MMA can be used for all types of temps
| Bis-acryl can be used for either template techniques
84
Free-hand block (MMA):
it is a good technique because it doesn’t need any preparation ahead of time, it doesn’t require a
model, no study models for emergency appointment, this is perfect for that, and the block temp is
done only with MMA not with bis-acryl because the later doesn’t go through the second stage (the
doughy stage), which means it can’t be manipulated like MMA.
Time-tested, time-trusted, good for all kind of temps in different techniques
85
bis-acryl temporary materials
the most commonly used for temps, and it is composite-like material, auto-cured or
light-cured or dual-cured and it is the market leader about 75%.
Comes as squeeze guns with a appropriate amount of mixed material (not equal amount), and it has
different shades.
It is very popular and very good
86
Why are Fermit and Systemp not so good?
since we do not cement it (it is applied directly to the tooth) it might pop out and the patient cannot floss the
area, also it degrades quickly
87
Why is relining a MMA temp important?
to compensate for the shrinkage and distortion of the MMA since it is unfilled resin
88
The difference between tempbond and tempbond NE. its significance?
TempBond contains eugenol that interferes with the full polymerization of resin (the final cement), while
TempBond NE does not contain eugenol and is therefore PREFERABLE.
89
The steps involved in a free-hand block technique
The liquid should be poured first then the powder, then we wait to the second (doughy) stage, where you can pick it up and it doesn’t stick to your fingers, the third stage is the rubbery stage, which has a shape memory, or elasticity, the fourth stage is the final set, we should bring it to the mouth before it goes to the rubbery stage and let the patient bite down firmly into MIP, and in the late rubbery stage it should teased out of the tooth and let it bench set or in a hot cup of water. Pay attention to the highs and lows on the dough because they represent the opposing cusps and fossae. MMA is unfilled resin and shrinks upon setting, and it will be slightly distorted when teasing it off the tooth, so we should reline it to compensate for the shrinkage and distortion and 99% of the time, the first mixture doesn’t capture everything and it works as a shell and the inner details will be captured with the reline mix. We adjust the occlusion before relining, load the temp with the reline mix when it still in the runny stage, then rebite into MIP. Finish and polish with the same lathe as the acryl with pumice powder.
90
Two template techniques for temp crown
--Vacuum-formed template
| —Silicone template:
91
Vacuum-formed temps technique
Vacuum-formed: For temps it should be, rigid, clear and thin, it requires a pre-op study model, and to repair the tooth that we are going to prepare if it is broken using a blackout material of a light-cured composite directly on the pre-op model, using a horse shoe model to maximize the suction, the template should cover the tooth mesial and distal to the tooth we will prepare in this way we make it “ repositionable”, that’s why it is difficult to use this if the tooth we are going to prepare is the last tooth in the mouth because, distally it will be supported by soft tissues and it will easily pushed down too much or not much enough. It is a good idea to make vent holes on the occlusal from inside out on the non-working cusps on the tooth being prepared and the two adjacent teeth to eliminate the trapped air bubbles . With templates we can use either MMA or bis-acryl which is injected into the space of the fully prepared tooth only and in most of the time we don’t need to reline it, but if we do, we can reline it using flowable composite, and this material shrinks less than MMA .
92
Silicone putty template crown
Silicone putty template:
- Can be made either in the mouth (as long as we have an intact tooth) or on a diagnostic model,
- we can use a mini impression tray with it,
- the putty should cover the tooth will be prepared and a tooth on each side,
- then we allow it to fully set before removing it.
- Make sure it is repositionable, because it is the key of any template technique .
- create a “v” shaped vents using a scalpel on the sides of the prepared tooth and the adjacent teeth --to allow the material to ooze to minimize the trapped air bubbles
- -and to test the set of the material,
- use either MMA or bis-acryl, and remove it in the early rubbery stage
93
-cast gold alloys the most commonly used type
The most commonly used is type III
- soft enough to be malleable and workable and fits as you squeeze it,
- also hard enough and durable
94
Type II ,III vs type IV cast gold
- Type IV is a low content of gold and it is too hard, and
- type II is too soft.
- most commonly used is type III which is soft enough to be malleable and workable and fits as you squeeze it, also it is hard enough and durable
95
PFM disadvantages
1. it is made of two materials, and as there is a
metal frame work beneath the porcelain,
2. there is a big chance of porcelain chipping
3. It needs more reduction,
4. needs to be subgingival as it should be esthetic so it is more invasive to the tooth structure.
5.This material can not be used for indirect restorations.
96
Non-glass ceramics (alumina or zirconia ): Indications and contraindications
-Indication: the zirconia based ceramics are very
popular now especially for one-unit crown,
- Contraindication: cannot be used for inlay and onlay.
97
Glass ceramics (lithium disilicate): egs
-Emax inlays or Emax crowns
- also includes feldspathic
porcelain (the old fashion porcelain)
98
Glass ceramics: Indications
that the veneers, inlays, and Onlays
can be used in a milling machine, (not like gold restorations)
99
Class IV and V composite preparations: cavosurface margin
-90-degree cavosurface margin
- uniform depth of the axial line angles,
- but margins in enamel subsequently needs to be beveled
100
Class IV and V composite preparations: Preparation design
1. Bevel on enamel but not on root surface
-Class IV preps have a bevel of 1 mm at 45 degrees
-Class III has a bevel of 0.5 mm at 45 degrees as well.
2. Axial depth into dentin is determined by the extent of the defect
3. Axial wall should follow the original contour of the facial or lingual surface, which is convex
outward mesiodistally and sometimes occlusogingivally.
4. Groove retention form usually is not necessary;
-if needed, retention groove is placed on the roof
aspect
- retention groove on the incisive aspect is rarely required.
5. No need to break contact for both of these restorations
-unless the restoration has decay and you need to break contact to remove all the caries.
101
Class IV and V composite preparations: Why Bevel on enamel but not on root surface?
-The values of placing bevel on enamel margin are to have a lot more cut in enamel rods to bind to
-There is no value to bevel the root margin where
there is not enamel rod at all.
- As to root surface, you don’t want to over extend any further gingivally than you want to because it
would exacerbate microleakage in there.
102
Class IV and V composite preparations: When are bevels contraindicated?
You don’t place a bevel on the
| gingival margin if the gingival margin extends to the root surface.
103
What is the values of placing a bevel?
- The values of placing bevel on enamel margin are to have a lot more cut in enamel rods to bind to,
therefore:
1. Maximize retention;
2. Minimize microleakage;
3. Achieve a nicer aesthetic transition from one to another.
104
Class IV preps have a bevel of ____mm at ____degrees
1 mm at 45 degrees
105
Class III preps have a bevel of ____mm at ____degrees
Class III has a bevel of 0.5 mm at 45
| degrees
106
Is it mandatory to break contact for Class III and IV composite restorations?
No need to break contact for both of these restorations unless the restoration has
decay and you need to break contact to remove all the caries.
107
Bevels provide which of the following:
a. Resistance
b. Retention?
The bevel provides retention
108
When etching composites on anterior either etch with _____ or _____.
When etching composites on anterior either etch with
1. phosphoric acid or
2. use the newer systems.
DO NOT use self etch
109
In anterior composites, self-etch is highly recommended. T/F
F
DO NOT use self etch
(he’s mentioned several times not to use self etch)
110
For anterior composites in general make sure you do shade selection _____ (before/after) you isolate.
Select shade *Before* isolation
111
Type of light recommended for shade selection
Full spectrum light.
And make sure the tooth hasn’t dried because the tooth will lighten once it’s dry.
112
The tooth is fully dried before shade selection. T/F
F
| Make sure the tooth hasn’t dried because the tooth will lighten once it’s dry.
113
Etch times for anterior composites:
- Enamel
- Dentin
- Enamel: 15s
| - Dentin:5s
114
The consequence of over-etching dentin?
Etch dentin for 5 seconds
| or else you get *postoperative sensitivity*.
115
Bonding will create a _____
Bonding will create a hybrid layer
116
Bond to enamel is really good. Bond to dentin is
| initially good but then it weakens. T/F
T
117
Why should we cure incrementally?
Make sure to cure incrementally because
- it will guarantee the depth of cure
- reduce polymerization shrinkage problems with C factor
118
Why should you NOT use bulk fill composite in anteriors
- it is very translucent. Not esthetic
| - polymerization shrinkage problems
119
For finishing anteriors, if surface is convex, use _______
Surface is convex, use
- discs
- strips
120
For finishing anteriors, if surface is concave, use ____
Surface is concave, use
| -multi fluted carbides
121
Composite bonds to cementum.T/F
Composite does NOT bond to cementum
122
When margins are below the CEJ, amalgam filling will provide a better marginal seal compared to composites. T/F
T
Composite does NOT bond to cementum, so an amalgam filling for example will provide a
better marginal seal when margins are below CEJ.
123
Sandwich technique;
Glass ionomer+ composite:
| o Glass ionomer releases fluoride and has better bond to dentine on the long run.
124
Sandwich technique;
Glass ionomer+ composite:
| o Glass ionomer releases fluoride and has better bond to dentine on the long run.
125
When using GIC in Sandwich technique, why should we make sure that it is radiopaque?
Make sure it’s a radiopaque Glass ionomer
--so it won’t be mistaken for a recurrent
decay on X-rays.
126
Materials used in Sandwich technique;
Glass ionomer+ composite:
| o Glass ionomer releases fluoride and has better bond to dentine on the long run.
127
All Class V should be treated, but not necessarily restored. T/F
T
128
Common diagnosis when class V composites are used
■ enamel caries
■ root caries
■ faulty restorations
■ non-carious cervical lesions
129
Do all cervical lesions need to be treated ?
Yes
| But not all need to be restored
130
Do all cervical lesions need to be restored?
No
- All cervical lesions need to be treated
- but DO NOT need to be restored
131
What methods can be used for gingival displacement for Class V restorations?
● Cervical retraction clamp: can help displace the gingival tissue apically for visualization ( can be used for one tooth )
● Retraction cord: can help displace the gingival tissue apically for visualization (shrink the blood vessels Vasoconstriction in that area so the tissue will move down and away from the tooth)
132
Retention in Class V amalgam
● four retention points should be added to the dentin when restoring with
amalgam ( placed incisally and gingivally )
● or u can do retention grooves
● no need for bevel
133
Bevel is necessary for Class V amalgam. T/F
F
| no need for bevel
134
Root surface considerations for composites
Root surface considerations
○ keep preparation dry when restoring to prevent resin hydrolysis
○ do not etch too long to prevent collagen degradation
○ use chlorhexidine or glutaraldehyde after etch to prevent proteolytic enzymes from breaking down the hybrid zone of the bond
135
Why is chlorhexidine or glutaraldehyde used after etching
prevent proteolytic enzymes from breaking down the hybrid zone of the bond
136
What is recommended for initial flash removal in composite restorations?
#12 scalpel is recommended for flash removal
137
Why use flowable composite as 1st layer?
1st layer/increment - use flowable composite:
■ Low filler loading.
■ IT FLOWS very well into the corners of a preparation
■ Should use because:
● adapts very well to line angles and point angles
● doesn’t shrink with the same amount of stress
as regular composite therefore less likely to cause contraction gaps at the gingival margin
138
Placement techniques for flowable composite
● Squirt onto floor of prep and use explorer to bring right to the gingival margin
● Check for bubbles.
● Make sure it’s thin and covers all walls
● Cure it.
● Make sure to cure incrementally because it will guarantee the depth of cure and reduce polymerization shrinkage problems with C factor
139
Resin modified glass ionomer liner (Vitrebond) can be used instead of flowable composite. T/F
T
140
Vitrebond and flowable composites are applied AFTER etch priming and sealing. T/F
F
-Vitrebond (Resin modified GIC) is applied BEFORE etch priming and sealing
Flowables are applied AFTER etch priming and sealing
141
Vitrebond and flowable composites are BOTH applied AFTER etch priming and sealing. T/F
F
-Vitrebond (Resin modified GIC) is applied BEFORE etch priming and sealing
Flowables are applied AFTER etch priming and sealing
142
Advantages of using Vitrebond
● Release fluoride into surrounding tooth structure therefore making it more caries resistant (esp. good with high caries risk patient).
● Forms a very durable chemical bond to dentin (probably better than regular composite)
● Dispensed right amounts with ‘clicker’.
143
Sandwich technique procedure
```
-1st increment:
● Resin modified GIC
●Dispensed right amounts with ‘clicker’.
-2nd increment:
■ Apply dark, opaque composite (i.e. A3.5) to bank the composite to mimic
dentin.
■ Cure it
○ 3rd increment:
■ Feather a more enamel shade on top
○ Finishing/Polishing:
■ Remove gingival flash via #12 scalpel blade.
■ Use discs to finish and polish (should never need to use course disc)
■ Fine discs adapt very nicely
```
144
#1 cause of post-op sensitivity with Class V composites
● #1 cause of post-op sensitivity with Class V composites is
*Cementum abrasion with aggressive disc use*
145
Common problems with Class V composite restorations:
Common problems:
● #1 cause of post-op sensitivity with Class V composites is *Cementum abrasion with aggressive disc use*
■ Problem with contouring
● must follow the natural architecture of the tooth
● look from many different angles
● make sure it is not too flat
146
How can we avoid Metamerism during shade selection?
Use Full spectrum light ( full to avoid Metamerism)
-light can affect the shade of color
147
Body shade
a shade in between enamel and dentin opacity and translucency (mostly used)
148
Teeth are multichromatic. T/F
T
You can use different shades for a big filling going incisally shades will change and you can
use a layering technique
149
Body shade for translucent teeth will give good esthetic results
F
| Don’t use body shade for translucent teeth
150
Different thicknesses of the same shades will look like they are different shades. T/F
T
Different thickness of the same shades will look like they are different shades
--because of how the light hit them and reflect it.
151
-The restoration will look dark right after you remove the rubber dam in comparison to the
surrounding teeth.
- If you have selected the correct shade before rubber dam placement, the shade will be the same the day after.
T/F
Both are T
- The restoration will look dark right after you remove the rubber dam in comparison to the surrounding lighter looking tooth.
- The shade will be the same the day after
152
Best way to pick a shade is to do a mock up. T/F
T.
Best way to pick a shade is to do a mock up. Pat the composite on the tooth and cure and then confirm
153
Why use a rubber dam?
```
○ Infection control
○ Best way to establish good isolation
○ Protection:
■ Yourself
■ Patient
○ Avoid contamination of the preparation
○ Mandated in school
```
154
Clamp function
Prevents rubber dam popping off during procedure
155
Clamp placement
Clamp placed on the tooth behind the one you are working on
156
Clamp placement
■ Clamp placed on the tooth behind the one you are working on
■ The jaws (bows) of the clamps must be below height of contour of the tooth
■ Atraumatically placed
■ Secure
157
Why are Some clamps Winged?
○ Allows placement of rubber dam & clamp in one go
158
Wedjet
○ Cylinder of latex.
| ○ Keeps the dam in place in the anterior area
159
Why Invert rubber dam?
■ Prevents saliva/ blood leaking in
| ■ Use flat plastic
160
wax floss ligature?
Can use a wax floss ligature around the tooth to seal it off even more
■ Generally more necessary for anterior teeth
161
Cervical Retraction clamp
```
○ Rubber Dam clamp
○ Primary purpose is for class V restorations
○ Engages the tooth in the cervical area
○ Also retracts gingiva
○ May also be used for single tooth endodontic isolation
○ Two different sides
■ Facial side (More open side)
■ Lingual Side
```
162
Cervical Retraction clamp: disadvantage
○ Disadvantage
| ■ Can only do one tooth at a time
163
What’s a cervical matrix?
1. Matrix for a Class V (very different from class II and III). 2. Two generations:
- -1st generation is clear plastic
- -2nd generation is blue plastic.
3. It's a stiff plastic (many sizes), either transparent or blue translucent (want light to shine through therefore will never be orange or opaque).
4. Adapt well to cervical area.
5. Have 3D curvature.
6. Easily customizable.
7. Has a plastic handle to place on tooth.
164
How to place/use a cervical matrix?
How to place:
-After placing the 3rd, superficial layer place the cervical matrix with gingival part of matrix
under gingival tissue,
-then move the matrix down so the excess runs
incisally.
-This technique is like a “closing door”and minimize gingival flash and give a very smooth surface with a minimum of finishing
-Cure when in place.
-No air inhibited layer and it will yield a very shiny
surface.
165
How to place/use a cervical matrix?
How to place:
-After placing the 3rd, superficial layer place the cervical matrix with gingival part of matrix
under gingival tissue,
-then move the matrix down so the excess runs
incisally.
-This technique is like a “closing door”and minimize gingival flash and give a very smooth surface with a minimum of finishing
-Cure when in place.
-No air inhibited layer and it will yield a very shiny
surface.
166
Other techniques like cervical matrix:
Other techniques: Clear plastic strip with cut-out where it will be placed next to the gingival
margin. Very difficult to use because it's hard to slide in on the mesial and distal as the tooth isn’t
prepped on the proximal.
167
What has been the impact of tetracycline discoloration on dentistry?
The discoloration started the cosmetic dentistry field. Specifically started the composite veneers.
168
Direct veneer
Typically for the direct veneer we don’t reduce the incisal edge unless there is a filling already
there
169
indirect veneers
With indirect veneers we can be more aggressive in reduction and reduce the incisal edge
because the material we’re using is better.
170
61. Direct veneers disadvantages
Direct veneers are not that good…they fail because
-they’re harder to make (need more talent
and time)
-they don’t have the color stability
-Don't have dimension stability.
-They also have cohesive (not adhesive) failures.
