Bonding in Dentistry: Adhesive System

Penetration fo resin and formation of resin tags within the tooth surface

Mechanical adhesion

Chemical bonding to the inorganic component (hydroxyapatite) or oganic components (mainly type 1 collagen) of tooth structure

Adsorption (chemical or true)

Precipitation of substance on the tooth surfaces to which resin monomers can bond mechanically or chemically.

Diffusion

Adhesion can be a combination of what 3 things?

Mechanical, adsorption, and diffusion adhesion

What are the requirements for a successful adhesion? (4)

1. Clean surface

2. Eliminated voids at the interface

3. High bond strength

4. Stability and longeviity

The adhesive surface should _____ the substrate well, have a ____ contact angle, and spread onto the surface.

wet, low

Enamel composition?

Inorganic 86%

Organic 2%

Water 12%

Dentin composition?

inorgnaic 50%

organic 30%

water 20%

What is enamels vickers hardness?

274.8 HV

What shape are enamel rods?

Keyhole shaped

__________ secrete enamel matrix and are derived from oral ________ cells

Ameloblasts

ectodermal

Each enamel rod is formed by _______ ameloblasts and these rods interlock and intertwined to prevent what?

four

fracture and splitting of the tooth

_________ orientation in the rods head

__________ orientation to the head in the tail

long axis

cross axis

What is the maximum thickness of enamel?

2.5mm

What is the outer 20-40 microns of enamel called?

Aprismatic enamel

True of false: most outer enemel cracks remain inert and harmless

True

What are the 4 reasons enamel is so tough and durable?

1. Hierarchial tissue organization

2. Ability to guide and arrest cracks

3. Shielding effects

4. DEJ

Enamel tensile strength varies according to ______ orieintation

_________ enamel 42.2 Mpa

________ enamel 11.5 Mpa

rod

parallel

transversal

How long should you etch?

How much enamel surface is removed?

What does etch produce?

15 seconds max

10 microns

Monocalcium phosphate monohydrate precipitate

What is the bond strength of resin to etched enamel?

15 to 25 MPa

What 2 things cause degradation of adheisve resin?

1. Hydrolysis

2. Fatigue

What causes degradation of exposed collagen fibrils?

Intrinsic collagenolytic activity MMP and Cathespins

Acid»»»»»»> Primer»»»»»»»»Adhesive

3 step etch and rinse

Acid…………Primer/adhesive

2 step etch and rinse

Aicd/primer………… Adhesive

2 step self etch

Adhesive,primer,etch?

1 step self etch

4th generation?

5th generation?

6th generation?

7th generation?

3 step etch and rinse

2 step etch primer/bond

2 step etch/primer and bond

1 step

What are the 3 steps of total ech adhesive system?

1. Phosphoric acid etching gel is rinsed off

2. A primer containing reactdive hydrophilic monomers

3. An unfilled or filled resin bonding agent

Acid treatment not only alters the mineral content of th dentin but also alters what?

The surface free energy

When primer and bonding resins are applied to etched dentin, they penetrate the intertubular dentin, forming what?

Hybrid layer

What is scotch bond multi purpose?

3 step adheisve system

Are two step adhesive systems inferior to three step systems?

Yes, they are inferior in bond strength

What is single bond 3M, one step, gluma comfort bond?

Two step etch and rinse adheisve systems

Do self etch adhesive use weaker or stronger acids?

Weaker

What is clearfil SE bond and Xeno?

2 step self etch adhesive

Clearefil s3 bond, g bond, xeno 1v?

1 step self etch

What is the average length of resin composite success?

6-7 years

Replacemtn of failed restorations accoutns for nearly ______% of all restorative dentistry

70%

What are the 2 best dentin bonding adhesives?

3 step, and 2 step self etch

All in one universal adhesives have shorter what?

Shelf life