Materials + Restorative Flashcards
(173 cards)
1
Q
Composition of amalgam
A
- Alloy of silver, tin, copper, zinc.
- Tin: Helps with dimensional change.
- Copper: Prevents corrosion, reduces fracture.
- Zinc: Scavenger for oxygen, forming Zinc oxide in place of copper/silver/tin oxides which would weaken the structure.
-
Mercury: Wets alloy aka wetting agent
- ~50%
2
Q
What are the three forms of mercury?
A
- Elemental: Liquid at room temp, used in amalgam.
-
Organic: Methylmercury (most toxic), formed in water or soil by bacteria and can build up in fish.
- Can be formed in the mouth with saliva from elemental or inorganic form.
- Inorganic: Enters air from mining or deposits, burning coal/waste, manufacturing, exists in solid state.
3
Q
What are the main ways that humans are exposed to mercury?
A
-
Mercury Vapor: Dental restorations.
- Risk is from inhalation – excreted in feces and urine, as well as passing it to a fetus and breastmilk.
- Reduce by using a rubber dam and high volume air and water - m_ost risk is removing the amalgam._
- EPA mandated amalgam separated be used in dental offices by July 2020.
- Incinerated waste can release vapor.
- Methyl Mercury: From seafood.
- Inorganic Mercury: From food.
4
Q
Gamma phase: Amalgam
A
- Unreacted alloy particles are the gamma phase (mainly silver and tin).
- Gamma phase combines with mercury, forming gamma 1 and gamma 2 phase.
- Gamma 1: Silver and mercury.
-
Gamma 2: Tin and mercury.
- Early fracture and failure.
- Adding copper replaces gamma II phase and makes it stronger (Eta phase)
5
Q
Amalgam: MOA
A
-
Low-copper alloy
- Higher % of Gamma 2 phase → weakest phase prone to corrosion.
-
High-copper alloy
- Lower % of Gamma 2 phase → increased mechanical strength, resistant to corrosion.
6
Q
What are the three types of amalgam?
A
- Lathe-cut
-
Spherical
- Amalgamates more readily and condenses more.
- Less mercury.
-
Admixed
- Strongest proximal contacts
7
Q
Amalgam: Creep
A
Max is 5% to be ADA certified, increases in size.
- Modern alloy should have not have >1% creep.
- Hydrogen gas release in when zinc reacts with water if you don’t have good isolation.
- Excess moisture causes delayed expansion.
8
Q
Amalgam: Marginal seal
A
-
Marginal seal improves over time due to corrosion - the only one.
- Eta phase (Cu6Sn5): oxidizes and transforms into CuCl2 and CuO2, takes twice as long to make marginal seal (2 years).
- Gamma 2 corrosion can seal margins (Handbook).
9
Q
FDA re-classifying amalgam in 2009?
A
- Class II device (having some risk) and designated guidance that included warning labels:
- Possible harm of mercury vapors.
- Disclosure of mercury content.
- Contraindications for persons w/ known mercury sensitivity.
- Limited information regarding dental amalgam and the long-term health outcomes in pregnant women, developing fetuses, and children <6yo.
10
Q
Amalgam: Indications
A
- Replace primary and permanent tooth structure lost due to:
- Active caries that has caused visible cavitation.
- Enamel defects or malformation that do not enlarge beyond the material’s limits.
- Restoration of moderate sized carious lesions when isolation cannot be achieved.
- Strong evidence supports safety and efficacy of dental amalgam in all populations.
11
Q
What is the % survival for Class I-V amalgams in primary teeth?
A
-
Primary teeth: 85-96% at 7yrs.
- Average annual failure rate: 3.2%
- Strength of evidence: Strong
12
Q
What is the % survival for Class I amalgams in permanent teeth?
A
-
Permanent teeth: 90-99% at 7yrs (Handbook)
- 89.8-98.9% (Guidelines)
- Strength of evidence: Strong
13
Q
What is the % survival for Class II amalgams in primary molars? In permanent molars + premolars?
A
-
Primary molars: 75% at 5yrs.
- Survive a minimum of 3.5yr and potentially in excess of 7yr.
-
Permanent molars + premolars: 92% at 10yrs.
- Mean annual failure rate is equal to composite = 2.3%
- Strength of evidence: Strong
14
Q
Amalgam: Prep design
A
- Strong under compression but weak under tension.
- Ideal prep floor is 0.5mm into dentin, 1.5mm from enamel surface.
- ⅓ of the intercuspal width.
- Convergent buccolingual walls, proximal box is wider at the cervical than occlusal, gingival wall should be flat not beveled .
- 1mm wide gingival seat.
15
Q
Amalgam: Trituration
A
- Trituration: aka mixing in capsule
- Problem is under-triturated mix: Dry, sandy, sets too rapidly, high residual Hg content.
- Higher trituration speed gives shorter working time, most of the time is under triturated and can appear dry and sandy.
16
Q
Amalgam: Condensation
A
- Back to back should be done at the same time
- Not going to be as strong immediately, but hardens over time.
17
Q
Amalgam: Longevity
A
- May be better than composite in the long run.
- Higher additional restorative tx when composites placed; 7x more than amalgam.
- High replacement rates of composite in general practice setting can be attributed partially to GP’s confusion of marginal staining for marginal caries and their subsequent premature replacements.
-
Guidelines conclude that median success rate of composite (92%) and amalgam (94%) are statistically equivalent after 10yrs.
- Equivalent mean annual failure rate = 2.3%
- Higher additional restorative tx when composites placed; 7x more than amalgam.
18
Q
Amalgam: Advantages + Disadvantages
A
- Advantages
- Economics
- Time efficiency
- Less sensitive to operator variables
- Historical longevity
- Wide application potential
- Disadvantages
- Esthetics
- Lack of bonding does not initially seal restoration and can increase mechanical stresses in the remaining tooth structure.
- In 2yr, Gamma 2 corrosion can seal margin.
- Mechanical retention required.
- Environmental concerns w/ proper disposal.
19
Q
Amalgam: Safety Concerns
A
- Mercury safety for human use + environment:
-
Human use: No evidence of harmful effects from the use of amalgam in humans.
- Ingestion: Amalgam associated mercury intake below toxic thresholds.
-
Allergy: Rare (<50 cases in 100yrs); lichenoid lesions have been reported.
- Replaced ONLY if lesion + amalgam contact.
- Use of rubber dam minimizes potential toxic risks.
-
Environmental:
- WHO:53% of mercury emissions comes from dental amalgam.
- EPA: Dental amalgam is a significant contaminant of wastewaters.
- ADA: Use amalgam separators and amalgam waste recycling.
-
Human use: No evidence of harmful effects from the use of amalgam in humans.
20
Q
How to minimize amalgam risks?
A
- Proper ventilation
- Pre-capsulated alloys
- Appropriate scrap disposal (check specific state regulations)
21
Q
SSCs: Composition
A
-
Chrome Steel
- 18% chromium
- 9-13% nickel
- 0.8-20% carbon
-
Nickel-Chrome Steel
- 15% chromium
- 77% nickel
- 7% iron
-
Surgical Grade
- 65-73% iron
- 17-19% chromium
- 9-12% nickel
- <2% manganese, silicon, carbon
22
Q
SSCs: MOA
A
- Full-coverage restorations restore form + function.
- Protects remaining tooth surfaces from caries formation.
23
Q
SSCs: Indications in primary + permanent teeth
A
- Primary teeth:
- Extensive caries – other restorative options likely to fail.
- Circumferential cervical decalcification.
- Developmental defects (hypoplasia, hypoplastic teeth).
- Following pulpotomy/pulpectomy.
- Strong consideration for use for high caries risk patients.
- Strong consideration for use when treatment is completed under sedation or GA.
- Hall crown technique: No removal of caries, no LA, no reduction of tooth surfaces to fit SSC.
- Fractured teeth.
- Abutment for space maintainer.
- Proximal box that extends beyond line angles.
- Permanent teeth:
- Extensive caries – other restorative options likely to fail.
- Developmental defects (hypoplasia, hypoplastic teeth).
- Financial considerations.
- Interim restorations.
- Needs full coverage but not fully erupted.
24
Q
SSCs: Safety concerns
A
Metal or nickel allergy
25
SSCs: Advantages + Disadvantages
* Advantages
* Protects remaining surfaces from caries formation.
* Restores form + function.
* All surface protection.
* Disadvantages
* Traditional SSCs are non-esthetic.
* **Increase in localized gingivitis (can be improved w/ optimal OH).**
* Periodontal concerns.
26
SSCs: Longevity survival rates
* Traditional SSCs on primary teeth – **95%**
* **Failure usually results from crown loss or perforation.**
* Hall crown survival rate – **95%**
27
SSCs: Contraindications
* Undergoing MRI
* Scatter; May opt for alternative if full case.
* Nickel allergy
* Recommend allergy testing
* Teeth exfoliating in 6-12mo
28
SSCs: Technique
* Not in supraocclusion; should not interfere with occlusion.
* Look at the tooth before prepping.
* **1.5-2mm** reduction.
* Restored before crown cementation.
29
SSCs vs. Class II amalgams/composites
* SSCs are more durable.
* Longest track record and highest degree of success.
* Dentists spend 50-60% of their time replacing restorations.
* Main reason for SSC failure is perforation.
30
SSCs: Gingival health
* Poor margins show gingivitis, extensions of the crown not associated w/ gingival health.
* Poor OH the most associated w/ unhealthy gingiva around SSCs.
* Takes ~2wks for healing.
* Bleeding is normal; cleaning will help to make healing faster.
31
SSCs: Cementation
* Resin is the best but there is usually a lot of bleeding.
* GI or RMGI are both acceptable (no difference)
* Polycarboxylate is the ***least effective*** cement.
* Chemical adhesion, but more temporary cement.
* Patch perforated crowns w/ composite, GI, RMGI – resin the least bc of the microleakage.
* Luting cements: Zinc phosphates, polycarboxylate, GIC, resin
32
What cement is the least effective for SSCs?
* Polycarboxylate is the ***least effective*** cement.
* Chemical adhesion, but more temporary cement.
33
SSCs: Bases + Liners
* At least **0.5mm** of material is needed.
* CaOH (Dycal)
* ZOE
34
SSCs bases + liner: CaOH
* Catalyst paste: Calcium hydroxide, zinc oxide, zinc stearate in ethylene toluene sulfonamide.
* Base paste: Calcium tungstate, calcium phosphate, and zinc oxide in glycol salicylate.
* Form an amorphous calcium disalicylate.
* **Alkaline pH aids in preventing bacterial invasion.**
* **Hydrolysis due to fluid contamination from dentinal tubules and microleakage.**
* Gingival displacement of restoration may lead to restoration breakdown.
* **Not good for directly under amalgam.**
* **Needs something placed over it.**
* Less soluble high-strength base should be placed - use visible light curing or RMGI.
35
SSCs bases + liner: ZOE
* Zinc oxide-eugenol; powder is the zinc oxide, rosin, and zinc acetate, liquid is the eugenol.
* **Low compressive strength, increase strength with polymethacrylate (IRM).**
* Forms a chelate of zinc eugenolate.
* **Sedative effect.**
* Eugenol is an inhibitor for resins and impression materials, need to put a barrier in between - causes problems with polymerization of resin.
36
Hall technique
* Place a crown over the tooth without local anesthesia and no reduction.
* Fill with GI cement and have patient bite down to place crown.
* Effective in behavior, more accepted because of no injection, most effective.
* Better than interproximal restorations, no difference between HT and traditional SSCs.
* Opens occlusion but within a month occlusion goes back to normal.
* More negative behavior in children who received conventional treatment.
37
Prefabricated Esthetic Crowns: MOA
* Full coverage restorations restore form, function, and esthetics for lifetime of tooth.
* Protects remaining tooth surfaces from caries.
38
Prefabricated Esthetic Crowns: Indications
[Same for SSC, except where esthetics are also important.]
* Extensive caries.
* Post-pulp therapy
* Tooth surface loss – erosion, abrasion
* Primary molar hypoplasia
* Inherited defects of dentition
* Traumatic injuries
39
**Similarities** between veneered SSC + zirconia crowns
* Harder to replace.
* Prefab crowns come in predetermined sizes + contours for primary teeth.
* Color, contour and sizing differ according to manufacturer.
* **Require passive fit so that circumferential tooth reduction is essential w/ subgingival feather edge finish line (overall 20% greater reduction than for SSC).**
* Occlusal reduction same as SSC (1.5-2mm).
* **No risk of pulp exposure due to preparation.**
* Adjacent and opposing crowns possible.
* Tooth colored
* Durable
* Retentive
40
**Differences** between veneered SSC + zirconia crowns
* Veneered SSC
* Tooth preparation – increased reduction on labial surface to accommodate bulk of composite **(0.6-1.5mm)**.
* Thicker cervical margin in composite.
* **1-1.5mm circumferential reduction; 1.5-2mm occlusal reduction.**
* Easy to adjust occlusion by reducing composite.
* Exposed metal margins can be crimped, but not advised.
* High risk of facing fracture over time.
* Composite facing may be damaged by heat sterilization.
* Not as technique-sensitive as zirconia.
* Hard to replace pre-veneered facing.
* Zirconia crowns
* Tooth prep requires equal circumferential reduction to accommodate thickness of zirconia which varies from **0.2mm at cervical margins** to **1.2mm occlusal surface**.
* Occlusal reduction same as SSC (1.5-2mm); circumferential reduction w/ subgingival feather edge finish line.
* Cannot be crimped so increased tooth reduction may be required for passive fit.
* Susceptible to fracture if excess pressure used while seating.
* Zirconia adjustment requires specific burs due to physical properties of zirconia.
* Excellent gingival response due to high polish + biocompatibility.
* Cementation or color may be compromised if fitting surface of crown is contaminated w/ saliva/blood.
41
What are the two types of pre-fabricated esthetic crowns?
* Veneered SSC: SSC w/ composite veneer attached via physical or chemical means.
* Zirconia crowns
Both may be used for anteriors, cuspids, posteriors.
42
Prefabricated Esthetic Crowns: Longevity, survival rates
* Veneered SSC: **Survival rate similar to SSC after 3yrs**, but veneer loss increases w/ time.
* Zirconia crown: Unknown – limited studies available.
43
Primary anterior crowns: Indications
* Multiple surfaces
* Incisal edge involvement
* Pulp therapy
* Hypoplastic
* Poor moisture
* Large single surface
* Poor OH
* Discolored incisors
Composite crowns usually replaced 2yrs after – not for long term durability?
44
Zirconia Crowns:
* **Zirconium dioxide (ZrO2) stabilized w/ Yittria.**
* **Tetragonal form** is what we use in dentistry.
* Properties:
* **High strength – 1000-1200MPa**
* Unreactive chemically
* Insoluble in water
* High thermal stability
* Highly polishable
* Cannot be crimped
* Not damaged by autoclave sterilization
* Exceed the max bite force of 6-8yo.
* Good for bruxers.
* Gingival health is better than SSC; plaque does not like zirconia.
Not as resistant to fracture as SSC.
45
What is the #1 reason zirconia crowns fail?
Pulpal complications
46
What is the biggest problem/concern w/ zirconia?
Abrasion of the opposing teeth.
47
Considerations when cementing zirconia crowns
* All types of cement
* Need good hemostasis
* Fill ¾ full
* Cement both incisors at the same time.
48
What factors can make anterior esthetic restorations in primary teeth challenging?
* Small size of teeth
* Close proximity of the pulp to the tooth surface
* Relatively thin enamel
* Lack of surface area for bonding
* Behavior
49
Class III (interproximal) restorations of primary incisors: Prep Design
* Labial or lingual dovetails to increase surface area for bonding and to increase retention.
* Isolation must be adequate.
* RMGIC has been recommended with poor isolation? (Handbook)
* High caries risk patients may be better served w/ placement of full tooth coverage restorations.
50
Class V in primary incisors
If isolation is poor, GIC or RMGIC is suggested
51
When are full coronal restorations of carious primary incisors indicated?
* Caries present on multiple surfaces.
* Incisal edge is involved.
* Extensive cervical decal.
* Pulp therapy is indicated.
* Caries may be minor, but OH is poor.
* Behavior makes isolation difficult.
52
Strip crown retention after 3yrs %?
* **80%** completely retained after 3yr.
* **20%** partially retained.
* **None** completely lost.
53
Recommendations for SSC's
* SSC use is supported on high-risk children w/ large or multi-surface cavitated or non-cavitated lesions on primary molars, especially when children require advanced behavior guidance techniques [including GA].
* Using SSCs in permanent teeth as a semi-permanent restoration to tx severe enamel defects or grossly carious teeth.
54
Evidence of efficacy of **amalgam** in primary + permanent teeth: Class I-V
* Class I
* Primary: **Strong evidence**
* Permanent: **Strong evidence**
* Class II
* Primary: **Strong evidence**
* Permanent: **Strong evidence**
* Class III
* Primary: No data
* Permanent: No data
* Class IV
* Primary: No data
* Permanent: No data
* Class V
* Primary: *Expert opinion*
* Permanent: No data
55
Evidence of efficacy of **composite** in primary + permanent teeth: Class I-V
* Class I
* Primary: **Strong evidence**
* Permanent: **Strong evidence**
* Class II
* Primary: **Strong evidence**
* Permanent: **Evidence in favor**
* Class III
* Primary: *Expert opinion*
* Permanent: *Expert opinion*
* Class IV
* Primary: No data
* Permanent: No data
* Class V
* Primary: **Evidence in favor**
* Permanent: **Evidence in favor**
56
Evidence of efficacy of **glass ionomer** in primary teeth: Class I-V
* Class I
* Primary: **Strong evidence** (ART trials)
* Permanent: **Strong evidence** (ART trials)
* Class II
* Primary: **Evidence against** (conflicting evidence from ART trials)
* Permanent: **Evidence against**
* Class III
* Primary: **Evidence in favor**
* Permanent: **Evidence in favor** (preference when moisture control is an issue)
* Class IV
* Primary: No data
* Permanent: No data
* Class V
* Primary: *Expert opinion*
* Permanent: *Expert opinion*
57
Evidence of efficacy of **RMGIC** in primary teeth: Class I-V
* Class I
* Primary: **Strong evidence**
* Permanent: **Strong evidence**
* Class II
* Primary: *Expert opinion* (small restorations; life span 1-2yr)
* Permanent: No data
* Class III
* Primary: *Expert opinion*
* Permanent: *Expert opinion*
* Class IV
* Primary: No data
* Permanent: No data
* Class V
* Primary: *Expert opinion*
* Permanent: **Evidence in favor**
58
Evidence of efficacy of **compomers** in primary teeth: Class I-V
* Class I
* Primary: **Evidence in favor**
* Permanent: **Evidence in favor** (evidence from studies in adults)
* Class II
* Primary: **Evidence in favor**
* Permanent: No data
* Class III
* Primary: No data
* Permanent: *Expert opinion*
* Class IV
* Primary: No data
* Permanent: No data
* Class V
* Primary: *Expert opinion*
* Permanent: *Expert opinion*
59
Evidence of efficacy of **SSC** in primary teeth: Class I-V
* Class I
* Primary: **Evidence in favor**
* Permanent: **Evidence in favor** (for children + adolescents w/ gross caries or severely hypoplastic teeth)
* Class II
* Primary: **Evidence in favor**
* Permanent: **Evidence in favor** (for children + adolescents w/ gross caries or severely hypoplastic teeth)
* Class III
* Primary: No data
* Permanent: No data
* Class IV
* Primary: No data
* Permanent: No data
* Class V
* Primary: No data
* Permanent: No data
60
Evidence of efficacy of **anterior crowns** in primary teeth: Class I-V
* Class I
* Primary: N/A
* Permanent: N/A
* Class II
* Primary: N/A
* Permanent: N/A
* Class III
* Primary: *Expert opinion*
* Permanent: No data
* Class IV
* Primary: *Expert opinion*
* Permanent: No data
* Class V
* Primary: *Expert opinion*
* Permanent: No data
61
Resin-based composites: Composition
* Resin matrix (bis-GMA, bis-DMA) w/ fillers (Handbook).
* Resin matrix + chemically bonded filler.
62
How are composites classified?
* According to their filler size, because their filler size affects:
* Polishability/esthetics
* Polymerization depth
* Polymerization shrinkage
* Physical properties
* Hybrid resins combine a mixture of particle sizes for improved strength while retaining esthetics.
* **Smaller filler particle size = greater polishability + esthetics.**
* **Larger filler particle size = strength.**
63
Flowable resins vs. Hybrid resins
Flowable resins = lower volumetric filler % than hybrid resins.
64
Composite classification by filler particle size
* **_Microfill_**
* **Excellent esthetics + polishability**
* **Elastic** = allows for tooth flexion under loading
* **_Hybrids_**
* **Bimodal or trimodal blends of fine or microfine**
* Excellent long-term results
* Good for posterior + anterior use
* **Low thermal expansion + polymerization shrinkag**e
* Relatively **high resistance** wear
* Up to **70% filler**
* **_Fine particle_**
* Contains **\>2 particle sizes**
* **High wear** resistance
* **Good mechanical** properties
* Appropriate for posterior use
* **Veneers needing strength**
* **Rougher surface** than microfill or hybrid
* **Higher filler loading (60-70% by volume, 77-88% by weight)**
65
Composite classification by clinical handling characteristics
* **_Flowable_**
* **Low viscosity** resin allows material to flow into prep
* **45-75% filler** by weight.
* **_Shrinks more._**
* **Lower filler content increases polymerization shrinkage + wear**
* **Higher filler content decreases shrinkage**
* **Indicated for PRR, Class III + IV, strip crown**
* **High filler content can be considered for Class I or II**
* **_Packable_**
* **High viscosity** resin allows instruments to push + shape material.
* Historically contains **higher % of filler particles improving wear resistance.**
* Indicated for **moderate to large Class I, II, III, V, strip crowns.**
66
Composite: Indications
* Replace primary + permanent tooth structure, especially in the esthetic zones, lost due to:
* Visibly cavitated active caries
* Enamel defects/malformation
* Traumatic injuries
* Use in moderate-low caries risk patients where you have good isolation.
* Class II that do not extend beyond the line angle, except when expected to exfoliate within 1-2yrs.
* Class II restorations in permanent teeth that extent ~⅓-½ bucco-lingual intercuspal width.
* Indirect resins allow more complete polymerization of resin.
67
Composite: Advantages
* Esthetics
* **Micromechanical seal between tooth + restoration**
* **Seals** cariogenic bacteria from fermentable carbs
* **Mechanically bonds** tooth together reinforcing structural integrity of tooth
* **Better wear resistance than GI or RMGI (historically, less wear than amalgam)**
* Many different forms (flowable, hybrid, packable, etc) for different applications
68
Composite: Disadvantages
* **Technique sensitive**
* **Comparable longevity to amalgam**
* Minor variations in technique + moisture alters performance
* **Chair time**
* Higher time investment for ideal placement
* Newer bulk-fill resins minimize this disadvantage
* **Recurrent caries**
* Most frequent cause for replacement
* **Polymerization shrinkage**
* **Constriction** when cured introduces stresses into tooth.
* **Incremental placement** can minimize stress
* Newer bulk-fill resins minimize this disadvantage
* **Post-operative sensitivity**
* **Result of polymerization shrinkage and poor bonding**
* Newer bonding agents may minimize this disadvantage
* **Wear resistance**
* Larger filler particles increase wear rates
69
Survival rate of resin-based composites w/ PRR/small pits + fissures: Primary + Permanent teeth
* **54% retention at 9yrs**
* Strength of evidence: Single report
70
Survival rate of resin-based composites w/ Class I: Primary + Permanent teeth
* Annual failure rate: **0-15%**
* Survival rate: **90% at 10 years**
* Strength of evidence: **Strong**
71
Survival rate of resin-based composites w/ Class II: Primary (= 2 surfaces/not extending beyond line angles) + Permanent teeth
* Survival rate:
* Primary: **\>90% at 3yrs**
* Strength of evidence: *Expert opinion*
* Permanent: **90% at 10yrs**
* Strength of evidence: **Strong**
* **RDI significantly increases restoration longevity.**
72
Survival rate of resin-based composites w/ Class III: Primary + Permanent teeth
* Annual failure rate: **0-4%**
* Primary
* Strength of evidence: *Expert opinion*
* Permanent
* Strength of evidence: **Strong**
73
Survival rate of resin-based composites w/ Class IV: Permanent teeth
* Annual failure rate: **0-4%**
* Strength of evidence: **Strong**
74
Survival rate of resin-based composites w/ Class V: Primary + Permanent teeth
* Survival + annual failure rate: Unreported
* Strength of evidence: *Expert opinion*
75
Survival rate of resin-based composites w/ strip crowns: Primary teeth
* Survival rate: **80% at 36mo**
* Strength of evidence: *Expert opinion*
76
Composite: Safety concerns
* **Bisphenol A (BPA):** Components of resin-based dental sealants and composites, related to polycarbonate + epoxy manufacturing.
* BPA **_not_** used in the manufacturing process, but is a byproduct of other components (bis-DMA).
* **Trace amounts of BPA derivatives are released from dental resins through salivary enzymatic hydrolysis and may be detectable in saliva up to 3hr after resin placement.**
* **May pose health risk due to their estrogenic properties.**
* BPA exposure level from dental products is **100,000x lower** than current exposure limits.
77
How do you limit BPA exposure when using composite?
* Wiping/rinsing composite restorations + using rubber dam
* Cleaning fill surfaces w/ pumice + cotton roll + rinsing
78
AAPD recommendation on BPA exposure w/ composites?
Considering the proven benefits of resin-based dental materials and minimal exposure to BPA and its derivatives, it is recommended to continue using these products while taking precautions to minimize exposure.
79
Amalgam vs. composite: Secondary caries rate
* **In permanent molars, composite placement after 3.4yrs was no different than amalgam, but after 7-10yrs, the replacement rate was higher for composite than amalgam.**
* **3.5x greater for composite vs. amalgam**
80
AAPD recommendations: Composite
* Primary molars, strong evidence that composite is useful for Class I.
* Class II, success for 2yrs in one RCT.
* Permanent molars, strong evidence from meta-analysis that it's successful w/ Class I + II's.
* **Enamel + dentin bonding agents decrease marginal staining + detectable margins for different types of composites.**
81
Microfilled composite
* Micrometers (**40nm**
* **50% filled per volume**
* **Excellent esthetics + polishability**
* **Elastic** = allows for tooth flexion under loading
82
Nano composite
* **20-75nm**
* Silane coated
83
Hybrid composite
* Likely what you are using.
* **Bimodal or trimodal blends of fine (40nm) + microfine (200-300nm)**
* Excellent long-term results.
* Best physical properties = universal.
* Good for posterior + anterior use
* **Low thermal expansion + polymerization shrinkag**e
* Relatively **high resistance** wear
* Up to **70% filler**
84
Microhybrid composite
**\<1 um; typically 70-80% filler**
85
Composite: Contraindications
* Isolation is poor.
* Young kids at high caries risk.
* Visible biofilm w/ many caries.
86
Bulk-fill composite: Advantages + Disadvantages
* Advantages
* Increased depth of cure
* Decreased time to cure
* Less technique
* Disadvantages
* Greater translucency
* Poor esthetics
* Extra equipment
* Shrinkage + post-op sensitivity
87
Acid etching: MOA
* Dentin-enamel conditioning.
* Remove or modify smear layer.
* Increase permeability (acid etches smear layer)
* Demineralize underlying dentin.
* Enamel etching _required_ for resin restorations.
* In vitro evidence exists that etching improves compomer retention.
88
Acid etching: Application
* Etchant (EDTA, phosphoric acid, maleic acid, nitric acid) should be applied to both enamel + dentin for 15-30 sec to create **_micro-retentive porosity_**.
* Enamel can be dried to white, frosty appearance.
* Dentin should remain moist and **_not dehydrated_**. If dehydration occurs, remoisten w/ water or HEMA.
* Overcomes the smear layer from the handpiece.
89
Smear layer: What is it?
* Created during preparation.
* **~1-5microns thick.**
* Contains dentin chips, debris, partially denatured collagen.
* Removed by conditioners.
90
Dentin-enamel bonding: MOA
* Structure of tubules affects bonding surface.
* Monomers w/ hydrophilic + hydrophobic groups.
* Two groups:
* Halophosphorous esters of **bis-GMA: more** **hydrophobic**.
* Halophosphorous esters of **hydroxyethyl methacrylate (HEMA): Miscible in water.**
* Rely on phosphate calcium bond for retention.
91
Composite: Hybrid layer
* Hydrophobic for the resin; hydrophilic for the dentin + enamel.
* **No chemical bond w/ dentin, micromechanical retention.**
92
Thinning agents in bonding agent
Water, ethyl alcohol, butyl alcohol – need to dry
93
Which generations of adhesive do not require etch?
6th + 7th gen
["s" and “self-etch”]
94
What type of etch technique will you see less staining?
Total etch
95
4th generation adhesive: Steps, Characteristics
* Steps:
* **3 bottles:**
* **Etch**
* **Primer**
* **Adhesive**
* Characteristics:
* **On the market the longest, which means more studies.**
* **Very high in vitro bond strengths.**
* Reports of post-op sensitivity.
96
**5th generation adhesive:** Steps, Characteristics
* Steps:
* **2 bottles:**
* **Etch**
* **Primer + Adhesive**
* Characteristics:
* Fewer steps = less chair time
* Good in vitro bond strength, but less than 4th gen
97
**6th generation adhesive:** Steps, Characteristics
* Steps:
* **2 bottles:**
* **Etch + Primer**
* **Adhesive**
* Characteristics:
* Higher in vitro bond strength than 5th gen.
* **Reduced post-op sensitivity.**
* Concerns about bond deteriorating over time.
98
**7th generation adhesive:** Steps, Characteristics
* Steps:
* **1 bottle:**
* **Etch + Primer + Adhesive**
* Characteristics:
* “All in one”
* Only one material to manage.
* **Lower in vitro bond strengths.**
* **Evidence of reduced sensitivity.**
99
**Universal adhesive:** Steps, Characteristics
* Steps:
* **1 or 2 bottles:**
* **Etch may be applied for higher bond strength or not used if lower bond strength is clinically acceptable.**
* **Primer + Adhesive**
* Characteristics:
* W/ etch, bond strengths can outperform 4th generation adhesives.
* W/o etch, bond strength similar to 7th gen.
100
What is the sandwich technique?
GI or RMGI → Etch → Adhesive → Restore w/ composite
101
Resin infiltration: Composition
* Icon-Resin infiltrant
* Icon-Dry: Ethanol
* Icon-Etch: **15% hydrochloric acid**
* Icon-Infiltrant: **Methacrylate-based resin matrix, initiators, additives**
102
Resin infiltration: MOA
* Hydrochloric acid removes hard remineralized outer layer of non-cavitated lesion, allowing penetration of low viscosity resin into porous enamel.
* **No prep**
* **No restoration margin**
* **No separate adhesive step**
* Resin prevents further demineralization by blocking diffusion of acids.
* Enamel lesions lose white opaque color due to refractive indices increase, as a result of resin penetration.
103
Resin infiltration: Indications
* Prevention of proximal caries progression in permanent teeth.
* Non-cavitated lesions that radiographically extend from E1 to D1 (inner enamel to the outer ⅓ of dentin).
* Studies pending on the efficacy on proximal lesions in primary teeth, efficacy for use as occlusal sealant.
* Treatment of **white spot lesions** in permanent teeth.
* Minimize secondary caries.
104
How does resin infiltration (Icon) appear radiographically?
* Radiolucent; **Make sure it's charted!**
* Barium is not allowed into the pores of the enamel.
105
Resin infiltration: Safety concerns
Inadvertent soft tissue contact ulcerations from hydrochloric acid – rubber dam isolation or soft tissue barrier indicated
106
Resin infiltration: Advantages
Microinvasive technique
107
Resin infiltration: Disadvantages
* Treated lesions remain radiolucent – cannot add opaquer since molecule would be too large to absorb into lesion.
* Clinically difficult technique in the following situations:
* Young children
* Tight proximal contacts
* Requires time + cooperation
108
Resin infiltration: Longevity
* No evidence for primary dentition.
* Reduced proximal caries progression in permanent teeth – 3yrs (limited studies)
* Long term color stability of white spot lesions treated – unknown (limited studies)
109
**Glass ionomer cement:** Composition
* **Base: Calcium or strontium alumino-fluorosilicate glass**
* **Acid: Water soluble polymer**
* When mixed, acid-base rxn neutralizes pH + releases fluoride ions.
* Rxn **must have moisture** present.
* **Chemical bond.**
* If too thick, needs water and can pull water from the pulp → Sensitivity.
* Not good for Class II in primary molars, okay for Class I.
* Adhesion to tooth surface is greater than ortho bands or crowns, roughening internal surface may give better retention.
110
Glass ionomer: Physical properties
* Chemical bonding to enamel + dentin.
* **_Most are biocompatible_**.
* Thermal expansion similar to tooth; less shrinkage.
* Fluoride release + reservoir over time for at least 1yr.
* **Hydrophilic**, w/ decreased moisture sensitivity to resins (requires water).
111
What are 3 types of glass ionomer?
* **Luting** – crowns
* **Restorative** – class I + II restorations
* **Base/liner** – deep caries
112
RMGI: Composition
* Light-polymerizing liquid added to allow photo-initiation.
* Chemical cure continues after photo-initiation.
* Acid-base rxn completes cure.
113
RMGI: Physical properties
* Higher viscosity, less sticky, command cure
* More radiolucent than resin.
* Less wear resistance + lower fracture strength than composite.
* **Triple hardening: Initial curing of light sensitive resin, chemical resin cure, acid/base neutralization matures over time.**
* Not as moisture tolerant as GI.
* Improved durability + handling.
* Polyacrylic acid removal of smear layer vs. self-etching adhesive and light.
* Class I and II restorations in primary teeth; no evidence for permanent.
* Do not bevel – leads to high marginal fracture.
* Dovetail to have less adhesion failure.
114
Bioactive Materials: Composition
* Emerging category of materials – AKA Activa.
* **56% filler restorative; base/liner 45% filler.**
* **21% bioactive glass filler.**
* **Properties of both GI + composite.**
* **No BPA, bis-GMA or BPA derivatives.**
* Releases calcium + fluoride ions.
* Light activated followed by chemical cure.
* Initial wear data comparable to composite.
* Very limited data available: polymerization shrinkage, longevity, bond strength unnown.
115
Bioactive Materials: Physical properties
* Bioactive ionic resin matrix (Embrace) more water friendly.
* Shock absorption w/ rubber.
* **Chemical** bond.
* **No bis-GMA or BPA derivatives.**
* Releases calcium + phosphate + fluoride.
* **Chemical + light cure.**
* Should be in contact 20 sec before curing.
* Manufacturer states no primer/adhesive is needed, however failure rate is very high.
116
True GI: Indications
* Luting cements, liners, temporary restoration (ITR, ART), restoration repair.
* Not recommended for Class II restorations in primary teeth.
117
RMGI: Indications
* Replace primary tooth structure lost due to active caries or enamel defects where:
* Restoration will not undergo excessive force over extended years.
* **Isolation is adequate but not ideal, caries risk factors are still not controlled, or behavior requires quick delivery.**
* Replace dentin lost due to caries in permanent teeth where enamel will be replaced w/ another material.
* Repair a single margin of restoration w/ another material (amalgam, composite, SSC)
* Long-term temporization of tooth for caries control or deferred definitive treatment.
118
Bioactive Materials: Indications
* Potential for replacement of multiple surfaces of primary teeth lost due to caries or enamel defects.
* Potential for replacement of smaller single surface lesions in permanent teeth.
* More data is needed to clarify indications.
119
GI/RMGI: Longevity
Survival times of GI/RMGI is not well documented and studies have demonstrated **“at least 1y”**, but case reports and expert opinion support longer use of RMGI restorations in primary teeth.
120
GI/RMGI: Advantages
* **Bond to dentin + enamel via chelation.**
* **Leaches fluoride:**
* Reservoir of F- ions for varying length of time.
* RMGI release lower levels of F- ions.
* Bioactive materials release calcium + fluoride ions.
* **Biologically compatible w/ connective tissue.**
* **Thermal expansion similar to dentin.**
* **Low setting shrinkage.**
* **Bond strength of 10MPa** in “sandwich” technique.
* RMGI light-activated followed by chemical cure allows material to be placed in bulk
121
GI/RMGI: Disadvantages
* **Prone to porosity from acidic substances** (e.g. fluoride gels).
* Surface finish is not as smooth as resin **(initial data indicate bioactive materials have finish more similar to resin).**
* **Surface wear is greater than resin (initial data indicates bioactive materials may wear similar to resin)**.
* Poor anatomical form and marginal activity,
122
GI/RMGI vs. composite: Success
Composites are more successful than GI where moisture control is not a a problem.
123
How long have RMGI Class II restorations been shown to withstand occlusal forces on primary molars?
For at least 1yr.
124
Class I prep + GI, RMGI materials: Strength of evidence
* GI - Limited
* RMGI - Strong
125
Class III prep + RMGI, bioactive material: Strength of evidence
* RMGI - Expert opinion
* Bioactive material - Case reports
126
Class III prep + GI: Strength of evidence
GI - Expert opinion
127
Class V prep + GI: Strength of evidence
GI - Expert opinion
128
IRT/ART-single surface + GI, RMGI: Strength of evidence
GI,RMGI - Strong
129
IRT/ART-multi-surface + RMGI: Strength of evidence
Conflicting evidence
130
Interim Therapeutic Restorations (ITR)
* To treat superficial cavities, dysplastic enamel (hypocalcification, hypoplasia) in young “pre-cooperative" children where pharmacological management to manage behavior is either not available, not acceptable by parents, or is delayed because of scheduling or administrative errors.
* Caries are removed usually w/ hand instruments.
* RMGI/GIC placed, smoothed w/ plastic instrument, light cured.
* Topical fluoride varnish should be applied.
* A comprehensive preventive program initiated w/ frequent professional monitoring.
* Replacement can be discussed at future date, depending on child's behavior stability of restoration, and preventive outcomes.
131
ITR vs. ART
* ART has been endorsed by the WHO for restoring and preventing caries in populations with little access to traditional dental care where there's restricted restorative care.
* ITR uses similar techniques w/ different therapeutic goals.
* Used more so in contemporary dental practice in the US.
132
ITR: Indications
* To restore, arrest or prevent progression of carious lesions in peds/SCHN pts if traditional preps/restorations can’t be done and need to be postponed
* For stepwise excavation in children w/ multiple open carious lesions prior to definitive restoration in teeth
* For erupting molars when you can’t get good isolation for a definitive restoration
* For caries control prior to tx under general anesthesia
133
ITR + its effect in oral biome
* ITR usage shown to reduce levels of cariogenic oral bacteria [Mutans streptococci and lactobacilli] in the oral cavity after placement
* But can return to pretreatment counts in 6M if no other tx is provided
134
ITR Procedure
* ITR procedure
* Remove caries w/ hand or rotary instruments
* Minimize leakage of restoration w/ maximum caries removal from periphery of the lesion
* Restore w/ adhesive restoration material like GI or RMGI
* ITR greatest success when applied to single or small 2 surface restoration
* Follow up care w/ topical fluoride and OHI → improve tx outcome
* Especially if GI was used bc it has fluoride releasing and recharging properties
135
Reasons for ITR failure
inadequate cavity prep w/ lack of retention and insufficient bulk
136
AAPD policy on ITR
* ITR is beneficial provisional technique
* ITR used to restore and prevent progression of caries and when traditional prep/restoration cannot be done
* ITR can be used for multiple caries lesions prior to definitive restoration of teeth
137
Sealants: Indications
* **80-90%** caries in permanent teeth in pits/fissures.
* **44%** caries in primary teeth in pits/fissures
* Consider placement for high caries risk patients, posterior teeth w/ deep pits + fissures, and/or non-cavitated caries on occlusal surface.
138
Sealants: Primary vs. Permanent
Insufficient data to support use of fissure sealants in primary teeth
139
Sealants: Longevity
* For permanent teeth: **86% reduction after 1yr, 58% reduction after 4yr.**
* Good isolation indicated for sealant retention.
* Consider use of RD.
* Moisture control systems comparable to rubber dam and cotton product isolation.
* 4-handed technique more successful.
140
Veneered SSC: Advantage + Disadvantage
* Advantages
* Esthetic
* Restores form + function
* All surface protection
* Disadvantages
* Increased labial reduction
* Facing may fracture
* Facing may be damaged by heat sterilization
141
Zirconia: Advantages + Disadvantages
* Advantages
* Esthetic
* Biocompatible
* Restores form + function
* All surface protection
* Disadvantages
* Equal circumferential reduction to accommodate zirconia thickness
* Adjustment requires special burs
142
Dimensions of Class I/II prep
Cannot be deeper than 1.5-2mm due to large pulp chamber and thinner enamel + dentin
143
Traditional preparation indications
* Large lesions
* Teeth where isolation cannot be achieved
* Tooth with many lesions
144
What limits the extension of the axial wall in the mesial box?
Pulp horns are closer to DEJ (especially mesiofacial)
145
What anatomical features of primary teeth can lead to loss of gingival floor of prep with extensive gingival extension + retention for SSC?
Greater constriction of crown at CEJ, more prominent cervical constriction
146
Broader, flatter contact areas
* Clinical diagnosis of proximal caries more difficult
* Less need for contouring matrix bands
* Extending box buccal/lingually to break contact can result in too wide box width
147
What anatomical feature can result in fracturing of Class II restorations where box + isthmus join?
Relatively narrower occlusal table
Wider occlusal caries may require full coverage
148
Common errors in Class II cavity preps for primary teeth
* Restoration of 3 or more surfaces attempted in primary tooth that must remain in mouth \>2yr (full coverage indicated).
* Gingival contact w/ adjacent tooth not broken, therefore caries below contact not removed.
* Isthmus too wide, therefore not creating reverse S curve where occlusal portion joins to box.
* Box extended too far buccally or lingually.
* Flare between buccal and lingual walls of box too great.
* Axial wall not conforming to the proximal contour.
* Gingival floor of box too wide.
149
Options for **incipient/non-cavitated lesions** in anterior primary teeth
* Material options
* Active surveillance
* Resin infiltration
* Arresting protocols (SDF)
150
Options for cavitated anterior enamel lesions in anterior primary teeth: **\>18m until exfoliation (low risk, good isolation, good behavior)**
Composite, Bioactive materials, disking, ITR
151
Options for cavitated anterior enamel lesions in anterior primary teeth: **\>18m until exfoliation (high risk, poor isolation, poor behavior)**
RMGI, bioactive materials, ITR, disking, deferred treatment
152
Options for cavitated anterior enamel lesions in anterior primary teeth: **\<18m until exfoliation (high risk of symptoms)**
RMGI, bioactive materials, ITR
153
Options for cavitated anterior enamel lesions in anterior primary teeth: **\<18m until exfoliation (low risk of symptoms, no esthetic issues)**
Deferred tx, SDF
154
Options for cavitated anterior enamel lesions in anterior primary teeth: **\<18m until exfoliation (esthetic concerns)**
Composite, RMGI, BAM
155
Options for cavitated anterior enamel/dentin lesions in anterior primary teeth: **\>18m until exfoliation (Moderate size; low risk, good isolation)**
Composite, bioactive materials
156
Options for cavitated anterior enamel/dentin lesions in anterior primary teeth: **\>18m until exfoliation (Moderate size; high risk, poor isolation, poor behavior, GA)**
RMGI, bioactive materials, crown, SDF, ITR
157
Options for cavitated anterior enamel/dentin lesions in anterior primary teeth: **\>18m until exfoliation (Large; low risk, good isolation)**
Strip crown
158
Options for cavitated anterior enamel/dentin lesions in anterior primary teeth: **\>18m until exfoliation (Large; high risk, poor isolation, poor behavior, GA)**
Crown
159
Options for cavitated anterior enamel/dentin lesions in anterior primary teeth: \<**18m until exfoliation (low risk of symptoms before exfoliation)**
Deferred tx, SDF, EXT, any tooth colored restoration
160
Options for cavitated anterior enamel/dentin lesions in anterior primary teeth: \<**18m until exfoliation (high risk of symptoms)**
EXT, ITR, RMGI, bioactive materials
161
Options for cavitated anterior enamel/dentin/pulp lesions in anterior primary teeth: **\>18m until exfoliation (controlled risk factors, good isolation)**
Strip crown, crown
162
Options for cavitated anterior enamel/dentin/pulp lesions in anterior primary teeth: **\>18m until exfoliation (uncontrolled risk factors, poor isolation, poor behavior, GA)**
Crown, EXT
163
Options for cavitated anterior enamel/dentin/pulp lesions in anterior primary teeth: **\<18m until exfoliation**
Crown, EXT
164
By how much do sealants reduce the incidence of occlusal caries in permanent molars?
76% after 2-3yrs of follow up
Moderate quality of evidence
165
AAPD recommendation on sealants
Recommends use of sealants in primary + permanent molars w/ both sound occlusal surfaces and non-cavitated occlusal carious lesions in children + adolescents
Strong recommendation, moderate quality evidence
166
How does sealing permanent molars reduce costs to the health system?
* By delaying + preventing the need for invasive restorative treatment
* Especially those w/ “elevated caries risk”
* Under these conditions, sealants are cost-effective intervention
167
By how much do sealants reduce the incidence of occlusal caries in permanent molars compared to fluoride varnish?
73% after 2-3yrs of follow up
Low quality of evidence
168
AAPD recommendation on sealants compared to fluoride varnishes
Use of sealants compared to fluoride varnishes in primary + permanent molars, with both sound occlusal surfaces and non-cavitated occlusal carious lesions in children and adolescents
Conditional recommendation, low-quality evidence
169
Which type of sealant material should be used in pits and fissures of occlusal surfaces of primary and permanent molars on teeth deemed to have clinically sound occlusal surfaces or non cavitated carious lesions in children and adolescents?
* 10 RCT’s included in the meta-analysis : the use of GI sealants compared with resin-based sealants may reduce the incidence of occlusal carious lesions in permanent molars by 37% after 2 to 3 years of follow-up; however, this difference was not statistically significant
* Available data : GI sealants may increase the incidence of carious lesions by 53%; however, this difference was not statistically significant
* Assessing retention, GI sealants may have 5 times greater risk of experiencing loss of retention from the tooth compared with resin-based sealants after 2 to 3 years of follow-up
* overall quality of the evidence = very low
* risk of bias, inconsistency, and imprecision.
* No data in adult patients were identified.
170
Glass ionomer sealants compared with resin- modified GI sealants
* 1 RCT - the use of GI sealants compared with RMGI sealants may increase the incidence of occlusal carious lesions in permanent molars by 41% after 2 to 3 years of follow-up; however, this difference was not statistically significant.
* GI sealants would have 3 times greater risk of experiencing retention loss from the tooth compared with RMGI sealants after 2 to 3 years of follow-up
* overall quality of the evidence = very low
* risk of bias, and very serious issues of imprecision.
* No data in adult patients were identified.
171
Resin-modified glass ionomer sealants compared with polyacid-modified resin sealants.
* 1 RCT- RMGI sealants compared with polyacid-modified GI sealants may reduce the incidence of occlusal carious lesions in permanent molars by 56% after 2 to 3 years of follow-up; how- ever, this difference was not statistically significant
* RMGI sealants may increase the risk of loss of retention by 17% compared with polyacid- modified resin sealants after 2 to 3 years of follow-up; however, this difference was not statistically significant.
* overall quality of the evidence = very low
* risk of bias and imprecision.
* No data in adult patients were identified.
172
Polyacid-modified resin sealants compared with resin-based sealants.
* 2 RCTs- the use of polyacid-modified resin sealants vs resin-based sealants may increase the incidence of occlusal carious lesions in permanent molars by 1% after 2 to 3 years of follow-up
* not statistically significant.
* polyacid-modified resin sealants seem to reduce the risk of loss of retention by 13% compared with resin- based sealants after 2 to 3 years of follow-up;
* not statistically significant.
* overall quality of the evidence = very low
* risk of bias and imprecision.
* No data in adult patients were identified.
173
Polyacid-modified resin sealants compared with resin-based sealants recommendation
* The panel was **unable to determine superiority of 1 type of sealant over another**
* very low quality of evidence for comparative studies.
The panel **recommends that any of the materials** evaluated (for example, resin-based sealants, RMGI sealants, GI cements, and polyacid-modified resin sealants in no particular order) **can be used for application in permanent molars** with both sound occlusal surfaces and non cavitated occlusal carious lesions in children and adolescents. **(**Conditional recommendation, very low-quality evidence.**)**
