Restorative Dentistry

2016 Review

DisclaimerThe views expressed in thispresentation are those of the authorsand do not necessarily reflect theofficial policy or position ofThe Department of Defense, theUnited States Government or theAGD

Critical pH ◦ Enamel = 5.5

◦ Dentin = 6.5

Below this pH:◦ Hydroxyapatite is driven into solution

◦ Net result is demineralization

Critical organism: S mutans

Visual

Tactile

Radiographic

Transillumination

Caries disclosing agents

Elective tooth separation

Digital radiography

Qualitative Laser Fluorescence◦ DIAGNOdent

◦ Caries management by risk assessment (CAMBRA) is an evidence-based approach to preventing or treating dental caries at the earliest stages. Caries protective factors are biologic or therapeutic measures that can be used to prevent or arrest the pathologic challenges posed by the caries risk factors.

Light source may be visible light or laser diode

Viable for pit and fissures/occlusal caries only

Example: Diagnodent® (Kavo)

Recognizes pathological changes at early stage◦ Initial lesions, demineralization, etc.

Laser diode provides pulsed light onto tooth (655nm)

Healthy tooth structure: no fluorescence

Carious tooth structure: fluorescence extent of caries

Establishing Caries Risk

Low Medium High

No new carious lesions 1 new carious lesion > 1 new lesion

in 3 years in 3 years in 3 years

Adequately restored Exposed roots Hx of root caries

surfaces

Good oral hygiene Fair oral hygiene Poor oral hygiene

Regular dental visits Irregular visits Irregular visits

Incipient lesions Incipient lesions

with poor salivary flow

Ortho treatment Strep mutans >100,000

CFUs

Duraflor® varnish application each visit

OHI to include use of fluoridated toothpaste/rinse

Dietary Counseling

Xylitol gum

Digital or conventional

radiographic monitoring

Monitor closely with other

diagnostic techniques

Symptoms◦ Pain on chewing, pressure

pathognomonic- pain on release

◦ Sensitivity to cold, heat, sweets

Diagnosis◦ Masticatory test - Tooth Slooth

◦ Stain

◦ Transillumination

◦ Periodontal probing

Evaluation◦ Locate the fracture

◦ Evaluate the pulp/periodontium

Immediate treatment◦ Ortho band, reduce/round off cusp,

remove cusp, sedative restoration, bonded restoration?

Definitive Treatment◦ Complex amalgam, partial/full

coverage cast restoration

Catch-all phrase for abrasion, erosion or abfraction

Erosion-chemical; smooth and rounded

Abrasion-mechanical (cupped or notched)

Abfraction (and NCCL in general) is multifactorial

Attrition: natural wear of teeth vs teeth

Research by Garguilo, et al (1961)◦ Connective tissue attachment = 1.07 mm

◦ Epithelial attachment = 0.97 mm

◦ Sulcus = 0.7 mm

Maynard and Wilson (1979) ◦ If impinged on:

Marginal tissue recession

Apical migration of attachment

Sulcus

Epithelial

Attachment

CT Attachment

DENTINAL TUBULES

Caused by the movement of fluid in the dental tubules displaces odontoblastic cell bodies (Branstrom)

Forms before eruption

Forms most of teeth

Regularly arranged dentinal tubules◦ 1 micron wide at DEJ

◦ 5 microns wide at pulp

◦ 35,000/mm2 at DEJ

◦ 75,000/mm2 at pulp

Forms after eruption

Forms from very mild stimulus◦ Normal occlusion

Uneven deposition◦ Floor

◦ Roof of chamber

AKA Reparative Dentin

Forms in response to an insult

Odontoblasts killed and replaced by mesenchymal cells

Disorganized tubules

Decreases dentin permeability◦ Increases protection

1.5-3.5/day

Cavity Sealers 2-5m◦ Varnishes◦ DBAs

Cavity Liners < 0.5mm◦ Resins in thin layers◦ RMGI, GI, ◦ CaOH

Cavity Bases >0.5mm◦ RMGI◦ ZnPO4◦ ZOE

Summitt Oper Dent 1994

Use minimum thickness necessary◦ 0.5 - 0.75 mm under amalgam

Minimize extent of liner/base◦ Do not base to “ideal” outline

Function ◦ Reduce bulk of “shrinking” materials

◦ Block out undercuts

Choose high MOE material under amalgam

From extension for preventionto …

prevention of extension or ...

constriction with conviction

Bottom line: Restoration size no larger than necessary for caries removal and to provide adequate retention and resistance

Conservative preparation (prevention of extension)◦ Minimal loss of sound tooth structure

◦ Maintain tooth strength

Restoration strength increased◦ Smaller condenser size (amalgam)

◦ Occlusal contacts not on margins

Narrow occlusal outline ( or none)

Rounded internal line angles

Bevelled axio-pulpal line angle

Sharp axio-gingival

"S" or reverse curve

Proximal B-L walls converge occlusally

Conventional

Glass Ionomers Resin-Modified

Glass Ionomers

RMGI

Polyacid - Modified

Composite Resins

Resin Based

CompositeCOMPOMERS

Fluoride ReleaseCTE

TranslucencyTensile Strength

Fracture Toughness

Composition◦ Resin (matrix phase) - UDMA/Bis-GMA/TEGDMA

◦ Dispersed phase (fillers)

Inorganic- Quartz, Silica, Zirconium Silicate, etc

Organic- ground microfill

◦ Cured by free radical polymerization

◦ Coupling phase – silane adheres particles to matrix

◦ Resin adhesive chemically links (polymerizes) to resin matrix

5

2.5

1.0

.5

.04 .

Small Particle

Minifill

Point 4 Microfill

Mic

ron

s

Filler◦ Glass/quartz, 1-10 (80+%)

◦ Colloidal silica, .04 (10 - 20%)

50 - 88% filled by wt

40 - 70% filled by vol

Pro ◦ Good esthetics, reasonable polishability

◦ Good physical properties

Low CTE, low shrinkage, strong

Con◦ Higher MOE than microfill (possible

implications for “abfractions”

Less flexible

Uses◦ Suitable for class 1,2,3,4,5

Very smooth finish, excellent esthetics

Poor lab behavior, good clinical behavior

Higher coefficient of thermal expansion than hybrids

May show greater water sorption over time

MOE may actually improve performance in Class V’s (abfraction?)

Average particle size is 0.4 m

An attempt to have the “best of both worlds”

Layered, anatomical build-up advocated for maximum esthetics

Examples:

Point-4 (Kerr)

Esthet-X (Caulk)

Synergy (Coltene/Whaledent)

Apollo (DMD)

Vitalescence (Ultradent)

Renew (Bisco)

The concept: ◦ Higher resin content

◦ Less viscosity

◦ Better adaptation to cavity walls

◦ Shock absorption through gasket effect

Pro◦ Flow easily◦ Elastic modulus permits flex and flow which may

absorb stresses (Think class V)

Con◦ More resin, less filler and all the downsides◦ Questionable ability to withstand high stress and

wear◦ Flowability = runny, difficult to control

Bottom Line: Minimal data to support use in Class II boxes; Better margins, less leakage have not been demonstrated

Penetrates microcracks, irregularities

Seals tooth-restoration interface

Enhances longevity of restoration (Leinfelder)

Technique◦ Cure, etch accessible margins, dry

◦ Low viscosity bonding agent, cure

Fortify, Optiguard, Permaseal, Protect-it

Esthetics

It’s not amalgam ◦ environmental issues

◦ ”toxicity”

Non-conductive

Conservative preparation

Polymerization shrinkage

Marginal leakage

Secondary caries

Post-op sensitivity

Technique sensitivity

Wear resistance

All resin based composites shrink upon curing

Polymerization shrinkage places stress on enamel and dentin bonds

Resin shrinks towards the center of the mass of material, “pulling” on the walls as it shrinks

The configuration of the cavity preparation is important to consider

Competition between: polymerization contraction forces

strength of bonds to tooth

C = Total Bonded Area

Total Unbonded Area

higher C-Factor = more stress

A class 1 preparation has the highest C factor

C-FACTOR

C=2

C=1

C=1

C=2

C=5

Interproximal contacts difficult

Physical properties poorer than amalgam

Water sorption

Depth of cure?

Lack of foolproof DBA

Technique sensitive!

When esthetics critical Conservative prep

feasible◦ occlusal outline narrow◦ gingival margin in

enamel◦ centric stops on tooth

structure

No evidence of excessive occlusal wear

High caries risk

Extensive preparations

Heavy occlusal function

Lack of enamel

Subgingival extension

Isolation inadequate

Conservative, adhesive preparation◦ Rounded internal line angles

◦ Occlusal width 1/3 intercuspal distance

◦ Avoid centric stop

Proximal box◦ Retention grooves may be beneficial (Summitt, et al. Quint Int 1994; 25:251-257)

◦ Gingival margin in enamel if possible

• Pre-wedge• helps achieve contact

• protects RD and gingiva

• Conservative adhesive prep• rounded internal line angles

• occlusal width 1/3 ICD

• avoid centric stop

• Proximal box• retention grooves?

• No bevels on occlusal margins

• Bevel F & L of proximal box

• significantly reduces marginal leakage

• improves access to enamel rod ends

• improves access for finishing

• Bevel on gingival margin

• only if wide band of enamel present

Bevel

Round internal line angles

Do not extend/bevelFissureotomy

Limit preparation to only what you need for access to caries and undermined enamel

Don’t bevel occlusal

Consider bevel of F and L margins of boxes◦ improves access to enamel rod ends

◦ improves access for finishing

Bevel gingival wall only if abundant enamel

Metal bands acceptable◦ Should be thin (0.0010”) and pliable

◦ Burnish against contact

◦ Use with conventional tofflemire

Clear bands OK but:◦ Thicker, non-burnishable

◦ Strong memory

◦ High cost

Wooden wedges preferable◦ Slight compression holds gingival margin tightly

◦ Secure

◦ Inexpensive

Clear wedges (e.g. Premier Cure-Thru®)◦ No resiliency

◦ Quite expensive

◦ Enhancement of cure unproven

(Ciamponi, et al. Quint Int 1994; 25:599-601)

Difficult to establish contact◦ Composite is not condensable

◦ Some matrix systems aggravate situation

Proximal contours often not ideal

Finishing procedures can open contact

Wear can complicate matters◦ Results in flat surface

Pre-wedge, proper matrix

Careful interproximal finishing

Pre-polymerized pellet

Ceramic insert

Condensable/Packable Composites

Belvedere Composite Contact Former

Curing tip (Denbur)

Segmental Matrices with Bitine ring

Lack of enamel

Moisture control difficult

Bonding system manipulation challenging

Poor access◦ Curing “chancy”

◦ Finishing difficult

Longevity of bond to cementum suspect

Particularly indicated when no enamel at margin

RMGI fill apical to contact

Resin based composite coronal to contact

Decreased microleakage◦ Allows stress relaxation

◦ Decreases bulk of composite

◦ Predictable dentin bond

Burgess, et. al. Compend Cont Ed Dent 1996; 17: 731-748

Advantages◦ Chemical bond to dentin

◦ Chemical bond to resin

◦ Anticariogenic effects

◦ Volume reduction of resin

◦ Elastic bonding layer

Closed Sandwich

Open Sandwich

What are you placing in the box?

a. Packable composite

b. Flowable composite

c. Resin-Modified Glass

Ionomer

d. Compomer The only way to reduce the overall shrinkage is to use less composite

material…hence…the sandwich technique

Most Common Lights = Quartz Tungsten Halogen!

Light intensity = mW/cm2

Conventional curing = 400-500 mW/cm2.

◦ Note increase from standard 300mW /cm2 of 5 years ago

Why the interest?◦ Time savings

◦ High-tech bragging rites

◦ Wavelength—468nm

Think about meaning of numbers!◦ Light tip diameter should approximate diode

Barghi, et. al. J Dent Res 1995; (abstr 152)

Leonard, et. al. Oper Dent 1999; 1:31-37

◦ Large tip : diode overstates the output

◦ Demetron guidelines

> 300 is OK- 400-500 has become the standard

200 - 300 requires longer curing time (but OK)

< 200 a problem

New Curing Techniques◦ High intensity and Multi-mode curing

High intensity

Lasers

Plasma arc (PAC) lights

◦ Newer lights will offer multi-mode (variable intensity) curing

Designed to allow stress relief before final set

Don’t cure to the advertised depth (< 3mm)

Wavelengths too focused ◦ Photoinitiators in different materials may not be

sensitive in narrow range

Generate high internal polymerization forces

May form shorter polymer chains (thus poorer physical properties)

Expensive

Continuous vs Discontinuous

“Soft Start” (pulse delayed)◦ Short burst, delay, final cure

◦ Extends visco-elastic stage of resin curing

◦ Often used as generic term

◦ Specifically refers to discontinuous method

◦ No solid science to prove efficacy

Light Emitting Diode

No bulbs or filaments

Doesn’t heat up (as much)

More energy efficient

Longer life

First generation- much lower irradiance in milliwatts◦ <200 mW/cm2

◦ Poor performance

Versalux

Elipar Freelight

Second generation◦ 600 mW/cm2

◦ Very promising

Problem: some have narrow spectrum◦ Some materials won’t cure◦ Improving!◦ Some heat is still generated◦ More efficient than QTH◦ Spectrum may be more narrow

than QTH◦ LEDs undergo less degradation

than QTH LE Demetron

Ultraume

Enhances completeness of cure May actually increase stress in tooth◦ Versluis, et. al. J Dent Res 1996; 75: 871-

877

Potential for incorporation of voids Takes time Microleakage not significantly better,

regardless of filling technique◦ Hilton. Quintessence Int 1997; 28: 135-

144

Wibowo et al (1999) ◦ Studied seven techniques w/ incremental

placement of Class II composites

◦ NONE produced gingival margin free of marginal leakage

◦ Best outcome w/ RMGI in box (closed sandwich)

◦ Flowable comp & condensable had poor performance

50% sealant retention (single application) 10-15 years

Effective caries resistance even when majority sealant lost;

resin remains in deeper fissure

Most conservative of all

Most failures are from improper isolation/moisture contamination

If you seal over active caries the caries will most likely become bacteriologically inactive and the disease process stops.

Selected fossa well isolated from another fossa containing restoration

Incipient caries in pit & fissure confined to enamel

Occlusal caries on contralateral tooth

Carious lesions, diagnosed & undiagnosed at the base of the fissure are arrested by sealants (Mertz-Fairhurst, 1986; Handelman 1991)

Decision to use sealants on known carious lesions “is responsibility of the dentist”ADA Report on Sealants, JADA April 1997

Pit and fissure sealants in combination with small amalgam restorations

Non-coalesced pits and fissures around restoration sealed

Significantly improved marginal integrity

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Restore carious lesions with minimum of tooth removal

Prevent caries from attacking other pits and fissures

Advantages◦ Sustained fluoride

release/rechargeable

◦ Biocompatibility

◦ Adhesion to tooth structure

Ionic bonds to tooth mineral

◦ Coefficient of thermal expansion

Disadvantages◦ Short working time

◦ Long setting time

◦ Technique sensitive

◦ Brittleness

◦ Esthetics

Advantages◦ Combines benefits of glass ionomers and

composite resin

◦ Increased working time

◦ Improved physical properties

◦ Improved esthetics

◦ Immediate finishing

◦ Record of clinical success

Powder◦ Ion-leachable aluminafluorosilicate glass

Liquid◦ Water

◦ HEMA/Bis-GMA

◦ Polyacid (may contain photocurable side chains)

methacrylate groups grafted onto PAA molecule

◦ Photoinitiator

Net resin content is approximately 5%

Smear layer removal allows access to dentin surface

Softens surface to facilitate ion exchange

Energizes surface for better wetting

Rule of 200◦ Concentration x time = 200

25% PAA x 8 sec

Exposure to exogenous fluorides results in a transient rise in F- release (“recharge” phenomenon)◦ Wistrom, et al. J Dent Res 1995; 74: abstr 767◦ Hatibovic-Kofman. J Dent Res 1994; 73: abstr 260◦ Alvarez & Burgess. J Dent Res 1994; 73: abstr 259

Avoid acidic F formulations - may degrade surface◦ Burgess, 1996 ◦ Fluoride release greatest for GI, then RMGI,

compomer, least is with composite

Resin-based composites that contain GI components◦ Radiopaque alumino fluoro-silicate glass

◦ Acidic polymerizable monomers

◦ Light-curing polymers

Insufficient GI components for significant acid-base reaction◦ Won’t cure w/o light

Examples◦ Dyract AP, Compoglass F, Hytac,

F 2000

Subject to greater loading than anterior teeth

Endodontically treated posterior tooth should receive cuspal coverage

Posts indicated only when not enough remaining tooth structure or pulp chamber height to retain core

Carbamide peroxide◦ Initially 10% to 15%

◦ 10% C.P. 3.6% H2O2 + 6.4% Urea

◦ Higher concentrations now being marketed

Matrix ◦ Carbopol (B.F. Goodrich)

10% Carbamide peroxide with carbopol◦ Only concentration with ADA acceptance

◦ Longest track record

Action by oxygen free radical (oxidation reaction)◦ Organic molecules are broken down

to smaller, less-colored molecules

◦ Diffusion/penetration of tooth structure established

Alteration of the enamel◦ Changes light reflectance to cause an

apparent lightening

Aging-related discoloration

Mild to moderate tetracycline stains (variable success)

Fluorosis

Generalized mild to moderate staining

Pre/Post restorative (veneers, microabrasion)

Anterior teeth subjected to lateral forces

Routine use of post/core and crown not indicated

Post/core indicated if :◦ Insufficient remaining coronal dentin

◦ Tooth to be abutment for FPD or RPD

Severe staining of most types

Sensitive teeth (recession)

Smokers (relative)

Extensive restorative history

Unrealistic patient expectations

Known sensitivity to bleaching agent

Pregnant or nursing women

Tooth sensitivity

Soft tissue effects

Alteration of tooth structure?

Effect on restorative materials

Safety - Oxygen free radicals?

Bleaching frequently causes minor tooth discomfort

Sensitivity is transient Related to agent strength / exposure time Tooth sensitivity can be controlled by:◦ Reduction of exposure time/concentration◦ Fluoride treatment◦ Use of desensitizing agents◦ Desensitizing agents being added

by manufacturer

Most SEM studies of enamel surfaces show little or no change in morphology

Studies show no significant effects on physical properties of enamel

Salivary remineralization might reverse any physical changes that occur

Slight surface pitting with 50% H2O2 office bleach

Minimal to no effect on composite or porcelain

Change in color of composites insignificant

Increased release of mercury from amalgam,◦ 2 reports

Methacrylate temporary resins discolor orangish

Bis-acryl and polycarbonate not affected

Little to no gingival irritation with well fitting trays and use of rubber dam when indicated (In-office systems)

May irritate tissue at higher concentrations

Indices and gingival biopsies report no lasting effect

Some patients gingival health improves due to increased oral hygiene and oxygen tension

Depends on the type/degree of stain◦ Haywood advocates 4-6 months for severe TCN

cases

Should see lightening within 3-4 days Pt’s compliance before and after

treatment is key Effective 75 - 90% of selected cases◦ Depends on study

Longevity is reasonable, but variable◦ May require re-treatment periodically

35-50% Hydrogen Peroxide◦ Shofu HiLite

◦ Opalescence Xtra (Ultradent)

◦ Superoxol

35-40% Carbamide Peroxides◦ Accelerate (Den Mat)

Hydrogen Peroxide/Carbamide Peroxide Combos◦ White Speed (Discus Dental)

Long track record (a.k.a. “walking bleach”)

Must remove all composite from access

External cervical resorption concerns!◦ Adequate seal over RCT

◦ Consider saline/perborate vs superoxol/perborate

◦ Correlated with use of

Heat

High concentration bleaching agents

Chemo-mechanical removal of superficial enamel discoloration◦ 1986: Croll

18% HCL/Pumice mixture

Wooden applicator used for abrasion

◦ 1990: Croll

11% HCL/Abrasive paste

10:1 gear reduction handpiece/special mandrels

PREMA System

Indications

◦ Enamel fluorosis

Brown lesions, white, yellow

◦ Superficial enamel hypoplasia/hypocalcification

◦ Lesions less than 200 µ in depth

Most brown defects respond well

25-50% of white lesions are too deep

Contraindications

◦ Deep enamel lesions

◦ Tetracycline staining

◦ Dentinogenesisimperfecta

◦ Any discoloration of dentinal origin

Onlays

Desire 2.0 mm reduction over functional cusps

At least 1.5 mm over non-functional cusps

Desire bulk of ceramic at the margin

Rounded internal angles

Smooth walls2 mm

>2 mm

Tooth Reduction

Based on ceramic strength, not software designDimensions:

At least 2.0 mm in the central fossaAt least 2.0 mm in a F-L dimensionAt least 1.5 mm axially (box)

>2.0 mm

>1.5 mm

Preparation Guidelines

Smooth, sharp well-defined margins

Smooth divergent tapered walls (6o- 8

o)

Smoothly rounded internal angles

Exit angles and margins approaching 90o

Adequate tooth reduction

TaperedParallel Undercut