10- Temporary and Permanent Cements (Dr. Filokyprou)

Define the following:

- A binding agent used to firmly unite two approximating objects

- A material that, on hardening, will fill a space or bind adjacent objects

Cement

Define the following:

The process of attaching parts, or a restoration to natural teeth by means of cement

Cementation

Define the following:

Thin golden enamel painted on cast of prep to allow space for cement to exist between tooth and crown

Die spacer

What acts as...

- Luting agents to bond preformed restorations and orthodontic attachments in or on the tooth

- Cavity liners and bases to protect the pulp and foundations and anchors of restorations

- Restorative materials

Dental cements

What is the primary function of cement for cementation?

To fill the void between the restoration and the tooth, mechanically lock the restoration in place, and prevent its dislodgment during mastication

What has the following characteristics?

- Not adhesive

- Fill the microscopic space and create a strong physical attraction to both substrates

- Mechanical retention

First dental luting cements

What has the following characteristics?

- Chemical adhesion of the cement, tooth and restoration, micro-mechanical interlocking

Contemporary adhesive cements

Non-adhesive cement relies on _________

Micromechanical bonding of the tooth to the prep

All the following are requirements for cement except:

A) Adequate resistance to dissolution in oral environment

B) Biocompatibility, cariostatic, low viscosity, thixotropic

C) Adequate bond through mechanical interlocking and adhesion

D) High strength in tension, shear, and compression

E) Good fracture toughness to resist stresses at the restoration-tooth interface

F) Adequate working and setting time

G) Maximum precision

H) Easy removal of excess

G) Maximum precision -- you should have allowance for error

All the following are requirements for cement except:

A) High viscosity

B) Compressible into thin layers

C) Thixotropic

D) Biocompatible/ nontoxic to the pulp

E) Cariostatic

A) High viscosity (LOW!)

What are five classifications of cements?

- Length of time in function

- Matrix bond type

- Knowledge and experience of user

- Principal setting mechanism

- Basic main ingredients

Depending on the expected longevity of the restoration, a luting agent can be considered _________ or _________

- Definitive (long term)

- Provisional (short term)

ID the cement:

- Should have a relatively low strength, be easily handled and not irritate the pulp

- Examples: zinc oxide-eugenol (ZOE), noneugenol cements, calcium hydroxide pastes

Provisional cements

What are all of the following?

- Zinc phosphate

- Zinc silicophosphate

- Zinc oxide-eugenol

- Zinc polyacrylate

- Glass-ionomer

- Resin

Main ingredients of cement

What are all of the following?

- Phosphate

- Phenolate

- Polycarboxylate

- Resin

- Resin-modified glass-ionomer

Matrix bond type cement

This group of cements set by which reaction?

Glass ionomer, resin-modified glass ionomer, ZOE, zinc polycarboxylate, and zinc phosphate

acid base reaction

This group of cements set by which reaction?

Dissolution and reprecipitation in aqueous medium (calciumaluminate cements)

Water based

This group of cements set by which reaction?

Polymerization reaction (resin cements, compomers, and self-adhesive resin cements)

Resin based

2 types of cement classified based on knowledge/experience of use

1. Conventional: Zinc phosphate, polycarboxylate, glass-ionomer

2. contemporary: resin-modified glass ionomer, resin

Resin-modified glass-ionomer, resin are _____

Contemporary

One of the cements with the widest range of applications is ___________

zinc phosphate cements -- oldest cement available for dental use, and is the standard that other cements are compared to

ID luting agent:

- Main use is the provisional cementation of crowns and fixed partial dentures, and as a cavity liner in deep cavity preparations

- Powder/liquid ratio 3:1 or 4:1 for maximum strength

- Eugenol can have a soothing effect on pulpal tissue

- Can be an irritant on soft tissue

- Has good sealing ability and is resistant to marginal penetration

Zinc Oxide Eugenol (ZOE)

The working time of ZOE is long because __________ is required

Moisture

What is the setting time of ZOE?

2-10 min

All of the following are disadvantages of ZOE EXCEPT:

A) Low strength and abrasion resistance

B) Solubility

C) Disintegration in the oral fluids

D) Extensive anticariogenic action

D) LITTLE antiocariogenic action

Temporary cements using non phenolic components are often preferred due to what?

An inhibitory effect of eugenol on polymerization of methacrylate-based resins and luting composites

___________ materials contain a combination of different carboxylic acids in the liquid (long-chain aliphatic acids or aryl-substituted butyric acid) to react with zinc oxide particles

Noneugenol

ID the luting cement:

- Powder consists of zinc oxide with 10% to 40% finely divided natural or synthetic resins together with accelerators

- Liquid is mostly eugenol (which may contain dissolved resins and accelerators) as well antimicrobial agents

- Setting time is 7 to 9 minutes (can be lengthened by reducing the powder/ liquid ratio)

Reinforced zinc oxide-eugenol

_________-reinforced zinc oxide-eugenol can cause irritation in connective tissues. It may cause softening and discoloration of some resin restorative materials

Polymer

__________ is mainly used for provisional cementation of crowns and FPD, and as a cavity liner in deep cavity preparations

ZOE (zinc-oxide-eugenol)

Why is ZOE mainly used as a liner now?

Eugenol can have a soothing effect on pulpal tissue but can be an irritant on soft tissue

reinforced ZOE is reinforced with ___________

natural or synthetic resins/acrylics together with accelerators

T/F: ZOE can create problems for further permanent cementation, so a lot of temporary bonds have NE (non-eugenol) formulas to not have problems with bonding

TRUE

ID the luting cement:

- In EBA modified cements, the powder is mainly zinc oxide containing 20% to 30% aluminum oxide or other mineral fillers

- Liquid consists of eugenol and 50% to 66% EBA

- To obtain optimal properties, a high powder/liquid ratio (3.5g/ mL for cementation, and 5 to 6 g/mL for liners or bases) is recommended

Reinforced zinc oxide-eugenol

ID the luting cement:

- Adequate time in the mouth should be allowed for full setting

- Several days may be needed for the material to reach full strength

- Advantages: ease of mix, long working time, good flow characteristics, and low pulp irritation

- Disadvantages: critical proportioning, hydrolytic breakdown in oral fluids, liability to plastic deformation, and poorer retention than zinc phosphate cements

Reinforced zinc-oxide eugenol

What is the setting time of reinforced zinc-oxide eugenol?

7 to 13 minutes

ID the luting agent:

- Widest range of applications, from the cementation (luting) of fixed cast alloy and porcelain restorations and orthodontic bands to their use as a cavity liner or base to protect pulp from mechanical, thermal, or electric stimuli

- Powder is mainly zinc oxide (90%) with magnesium oxide (10%) and small amounts of pigments

- Liquid is an aqueous solution of phosphoric acid containing 45% to 64% H3PO4 and 30% to 55% water, 2% to 3% aluminum phosphate, and up to 9% zinc phosphate

Zinc phosphate cements

ID the luting agent:

- A chilled thick glass slab will help to slow the reaction and allows for the incorporation of more powder, giving superior properties in the set cement (recommended powder/liquid ratio is 2.5 to 3.5 g/ml)

- At room temperature, the working time at luting consistency is 3 to 6 minutes, and the setting time is 5 to 14 minutes

- Initial pH (2 min after mixing) is about 2 and increases to 5.5 in 24 hours

Zinc phosphate cements

ID the luting agent:

- Advantages: Zinc phosphate cement can be mixed easily and set to a relatively strong mass

- Disadvantages: Can cause pulpal irritation (due to the initial low pH), lacks antibacterial action and adhesion, is brittle, and soluble in oral fluids

Zinc phosphate cements

Retention of zinc phosphate cements is achieved by __________

Mechanical interlocking

_______ cements where developed to attempt to combine the strength properties of the phosphate system with the biologic acceptability of the zinc oxide-eugenol materials

Zinc polycarboxylate cements

ID the luting agent:

- Powder consists of zinc oxide, 1% to 5% tin or magnesium oxide, 10% to 40% aluminum oxide, and small percentages of stannous fluoride may be included to improve mechanical properties

- Liquid is 40% aqueous solution of polyacrylic acid or an acrylic acid copolymer with other organic acids

Zinc polycarboxylate

ID the luting agent:

- Powder/liquid ratio is 1.5 :1 by weight

- Should be mixed rapidly in 30 to 40 seconds

- Working time is 2.5 to 3.5 minutes

- Setting time is 6 to 9 minutes at 37ºC

- Bonding to clean enamel and dentin surfaces can occur through calcium complexation (The polyaclylic acid bonds to calcium ions on the surface of enamel and dentin)

Zinc polycarboxylate

What is the first cement known to have adhesion by chemical interaction?

zinc polycarboxylate

zinc polycarboxylate's chemical adhesion occurs via _________

calcium complexation

What luting agent has the following advantages?

- Low irritation

- Adhesion to tooth and alloys

- Easy manipulation, strength, solubility, and film thickness

Zinc polycarboxylate

What luting agent has the following disadvantages?

- Need for accurate proportioning, critical manipulation

- Low compressive strength

- Short working time

- Greater viscoelasticity

Zinc polycarboxylate

What luting agent has the following indications?

• indicated: restorations with good resistance and retention form, when minimal pulp irritation is desired

• contraindicated: implant crowns on titanium abutments

Zinc polycarboxylate

ID the luting agent:

- Powder consists of finely ground calcium aluminum fluorosilicate glass

- Liquid is 50% aqueous solution of a polyacrylic-itaconic acid or other polycarboxylic acid copolymer with about 5% tartaric acid

- Powder/liquid ratio is about 1.3:1

- Set time is 6 to 9 minutes (luting materials), with lining materials setting in 4 to 5 minutes, and restorative materials setting in 3 to 4 minutes

- Light curing materials set in about 30 seconds when exposed to light

Glass ionomer

What luting agent has the following advantages?

- Easy mixing

- High strength and stiffness

- Fluoride, release

- Good resistance to acid dissolution

- Potentially adhesive characteristics

- Translucency

Glass ionomer

What luting agent has the following disadvantages?

- Initial slow setting and moisture sensitivity

- Variable adhesive characteristics

- Radiolucency

- Possible pulpal sensitivity

Glass ionomer

T/F: Glass ionomer is a self-cure material, and newer products have a light-curing functionality too

True

What is the setting time for glass ionomer? (4)

- Used as a luting agent: 6-9 min

- Used as a liner: 4-5 min

- Used as restorative material: 3-4 min

- Light-cure: 30 seconds when exposed to light

Glass ionomers are mainly used as a __________ rather than as a cement

Liner

ID the luting agent:

- Hybrid material derived from adding polymerizable resins to conventional glass- ionomer cement

- Once mixed, the resin phase polymerizes quickly and the glass- ionomer phase proceeds slowly via an acid-base reaction

Resin-modified glass-ionomer cement

T/F: Resin-modified glass ionomer cement is a hybrid material derived from adding resins to conventional glass ionomer cement

True

T/F: Once the RMGI is mixed, the resin phase polymerizes quickly, and the glass ionomer phase proceeds slowly via an acid-base reaction

True

__________ is less susceptible to early erosion during setting, less soluble, and has higher compressive and tensile strengths than unmodified glass-ionomer luting cement

Resin-modified glass-ionomer

ID the luting agent:

- The restoration should be seated firmly with finger pressure

- The tooth should be well isolated and the material kept dry for 7 to 10 minutes to minimize loss of cement at the margins due to its early solubility

- Not recommended for luting all-ceramic restorations that are susceptible to etching or posts due to possibility of hygroscopic expansion

Resin-modified glass-ionomer

the addition of resin to GI (RMGI) makes it less susceptible to all of the following EXCEPT:

a. early erosion during setting

b. more solubility

c. higher compressive strength & tensile strength

B- LESS solubility

What do you need to make sure happens when using RMGI as a cement?

Tooth should be well isolated and material kept dry for 7-10 minutes to minimize loss of cement at the margins due to its early solubility

What is a popular example of a resin-modified glass ionomer cement?

RelyX

What are the applications of resin cement? (5)

- All-ceramic

- Metal

- Metal- ceramic restorations

- Veneers

- Post cementation in endodontically treated teeth

ID the contemporary cement:

- Popular choice

- High compressive/tensile strength

- Low solubility

- Aesthetic qualities

- Useful for all-ceramic, veneers, metal, post-cementation in ETT

- Most esthetic luting materials, different options of shade and translucency

resin cements

Resin cements are classified according to _________ (3)

mechanism of matrix formation:

1) Chemical (self) cure

2) light cure

3) dual cure

What has the main constituents?

- Predominant functional acidic monomers, blends of polymerizable monomers of methacrylates/ dimethacrylates (bis-GMA, UDMA, and TEGDMA/ polymethacrylates

- Additives (4-META, MDP): promote bonding to ceramics, metals

- Diluents (HEMA & TEGDMA): reduce viscosity

- Filler particles, activator initiator systems

- Contemporary Luting Agents Resin

Resin cements

ID the luting agent:

- Self-adhesive resin cements must be presented as separated two-part materials to avoid contamination and premature setting

- Most of current systems are dual-cure materials

- Transparent shade cements are recommended for HT ceramics

Resin cements

What luting agent has the following advantages?

- High compressive and tensile strengths

- Low solubility,

- Aesthetic qualities

- Most esthetic luting materials

- Different options of shade and translucency

Resin cements

T/F you can use light cure to cement on pfm restoration

FALSE -- light wouldn't reach the cement

T/F most of the resin cements are dual-cure

True

T/F: The greater the brightness of resin cement, the higher the color stability

FALSE - LOWER the brightness of resin cement, the HIGHER the color stability

Rely X is a 2 paste resin cement that works well with teeth that ________

Teeth that also have shading of A2 -- the built-in shade of the cement is A2

What is the biggest advantage of variolink resin 2 paste system?

You can play with the shading of the tooth by coloring the cement, or you can have the cement be a transparent cement

Define the following:

- Refers to the establishment of molecular interactions between a substrate (adherend) + an adhesive brought into close contact, creating an adhesive joint

- May occur by chemical or physical bonding, micro mechanical interlocking, or friction

Adhesion

Adhesive resin cements— bonding agent is needed to promote adhesion to __________

Dentin

Self adhesive resin cements (one-component materials) — aim to eliminate the steps of what?

- Etching

- Priming

- Bonding

What has the following benefits of bonding?

- Protects the restoration's interface against penetration of bacteria

- Improves interfacial sealing

- Increases retention of the restoration

- Strengthens the restoration especially for low-strength ceramics

Resin cements

Define the following:

Designed to be a single adhesive system for bonding to all surfaces relevant to restorative dentistry

Universal adhesives

What has the following characteristics?

— Bond to tooth surfaces, direct restoratives (methacrylate resin-based and glass ionomer or resin-modified glass ionomer), indirect restoratives (e.g., metals, glass-ceramics, and high-strength alumina and zirconia

— Are compatible with self-cure, light-cure, and dual-cure resin-based cements

Universal adhesives

What is the key for successful performance for universal adhesives?

To have the right hydrophilic-hydrophobic balance in the formulation

What contains...

1. A polymerizable acidic phosphate ester as primary functional monomer (modern adhesives use 10-MDP) which:

- Can etch tooth and other substrates

- Bonds to hydroxyapatite through the formation of soluble Ca2+

2. Common monomers: Bis-GMA, UDMA, HEMA

3. Photoinitiators, stabilizers, carrier solvents, silanes, zirconia primers

Universal adhesives

These are the steps of using resin cements to bond to what?

- Sandblasting with aluminum oxide is the most commonly used method to prepare metal substrates for receiving bonding resins or resin cements

- - Creates micro-retentive, high-energy surface

- Monomers such as 10-MDP and 4-META improve retention of cast alloy restorations (more effective with base metal alloys)

- Metal primers (inconsistent results)

Cast alloys

These are the steps of using resin cements to bond to what?

1. Etching with hydrofluoric acid

- - Attacks the glass phase of ceramics, leaving a mircoretentive honeycomb- like high-energy surface

2. Silane Primer

- - Improves the wettability of the resin cement on the ceramic surface and establishes covalent bonds with the ceramic surface and the resin cement

- Usually contain 3-methacryloxyproyltrimethoxysilane (MPS)

- Effective in bonding silica-based restorative materials

- Applications in bonding between:

- - Silica-based ceramics and resin

- - Polymeric matrix and fillers of resin composites (silanized fillers)

- - Resin composite repairs, ceramic repairs

Silica-based ceramics

These are the steps of using resin cements to bond to what?

1. Sandblasting with aluminum oxide to roughen the bonding surface

2. Zirconia Primer containing phosphate or phosphonate monomers

- - These monomers also contain a hydrophobic backbone and a methacrylate group that can copolymerize with the adhesive resin cement

- - Most widely used: 10-MDP

- Achieves direct bifunctional adhesion

- - With metal oxides (e.g. zirconium or aluminum oxide) via a phosphate ester group and

- - With the resin bis-GMA matrix via a methacrylate group

Zirconia ceramics

What is used for extra-oral cleaning paste for indirect restorations before cementation?

Ivoclean

What has the following composition?

Alkaline suspension of zirconium oxide particles in water.

Ivoclean

What has the following mechanism of action?

- Saliva and body fluids contain various forms of phosphate e.g. phospholipids which may react with the restoration surface and make cleaning difficult

- Due to the size and high concentration of the particles, it absorbs the phosphate contaminants and leaves a clean ceramic surface

Ivoclean

_________ inhibits the polymerization of resin, if a crown is planned to be bonded with resin cement → a non-eugenol cement should be used

Eugenol

_________ is an alternative to conventional zinc oxide eugenol cements with...

- Better translucency

- Reduced shade mismatching

- Dual-polymerization or light-polymerization

Interim resin-based cement

What has the following characteristics?

- Two-paste, dual-cure resin cement

- Self-adhesive

- Adhesive- when used with 3M Scotchbond Universal Plus Adhesive

- Automix Syringe

- Available in four color-stable, fluorescent shades

3M RelyX Universal Resin Cement

What has the following characteristics?

- Excellent self-adhesion to Zirconia, Metal and Enamel

- Superior self-adhesive bond strength to dentin

- Combined with Scotchbond Universal Plus Adhesive allows bonding to glass ceramics and enhanced bond strength to all substrates

3M RelyX Universal Resin Cement

What has the following characteristics?

- Works as a self-, selective- and total-etch adhesive for direct and indirect restorations

- Dentin-like radiopacity

- Works as a universal primer for all restoration materials

Scotchbond Universal Plus Adhesive

What Material?

- Compressive Strength: High

- Pulpal irritation: Low

- Solubility in water (wt%): <0.20

Ideal material

What Material?

- Compressive Strength: 70-200

- Pulpal irritation: Moderate

- Solubility in water (wt%): 0-0.01

Resin

What Material?

- Compressive Strength: 90-162

- Pulpal irritation: Mild to moderate

- Solubility in water (wt%): 1.25

Glass ionomer

What Material?

- Compressive Strength: 85-185

- Pulpal irritation: Mild to moderate

- Solubility in water (wt%): 1.00

RM Glass ionomer

What Material?

- Compressive Strength: 80-100

- Pulpal irritation: Moderate

- Solubility in water (wt%): 0.06

Zinc Phosphate

What Material?

- Compressive Strength: 55-85

- Pulpal irritation: Low

- Solubility in water (wt%): 0.06

Polycarboxylate