Cariology

Ergonomics

shortening of this muscle may contribute to radicular symptoms

pectoralis muscle, scalene muscles (neck), 

inspiratory muscles

scalene muscles

most prevalent muscular disorder among dentists

Neck pain (70-80%)

Right handed clinicians

between 7 and 1

left handed clinicians

between 5 and 11

RHD: 8-9

• maxillay and mandibular anterior toward

RHD: 9

• mandibular posterior toward

• maxillary posterior toward

RHD 12

• anterior away (maxillary and mandibular)

RHD 10-11

• mandibular posterior away

• maxillary posterior away

LHD 3-4

• maxillary anterior toward

• mandibular anterior toward

LHD 12

mandibular anterior away

maxillary anterior awayL

LHD 3

mandibular posterior toward

maxillary posterior toward

LHD 1-2

posterior away (max and man) 

low back MSD

60-70%

Shoulder MSD

65-75 %

neck

70-80% (most prevalent)

hand / wrist MSD

60-70%

shoulder complex

muscles:

• trapezius

• levator scapulae

• rhomboids

• serrates anterior

sources of radiating pain

• cervical radiculopathy

• thoracic outlet syndrome

• carpal tunnel cysdrome

thoracic outlet syndrome

compression of neuromuscular structures in the cervicothoracic region

• may cause global arm pain, paresthesias, weakness

main entrapment points of TOS

• scalenes (neck muscles)

• costoclavicular space

• pectorals minor

nerves that supply the arm travel through the shoulder region

• exit neck

• under clivicle/ collar bone

• under chest muscles

the arm

peripheral nerves: median, radial, ulnar

shoulder, upper arm, forearm, wrist

how many mmHg compression can damage nerve

30

fingertip pinch - 5 newtons

stretch

8-10 % tension can cause severe pain

11% reduce blood flow in 50% animal models

shortening of which muscle contributes to radicular symptoms

pectoralis minor

scalene

neuromuscular bundle of brachial plexus pass under

pectoralis minos

scalene muscles

inspiratory

• 26,000 breaths/ day

narrowing of space may contribute to radicular symptoms

costoclavicular space

2nd most prevalent MSD

lower back pain

critical pH of enamel

5.5

below this level (more acidic) : minerals dissolve

critical pH for dentin

5.5 - 7

more alkaline (more basic )

dentin is less calcified, progression of caries is faster

How long to progress from enamel to dentin. 

4-5 years

vinegar/ acid causes

EROSION

NOT CARIES

diminishes enamel from the outside

is pain felt in enamel caries ?

no

vertical transmission

from parent to child / during birth

horizontal transmission

between peers/ significant other

pellicle

glycoproteins is saliva

cover tooth immediately (good bacteria)

attachment of early colonizers

0-24 hours (immediately)

co-adhesion and growth of attached bacteria/ formation of micro- colonies

4-24 hours

microbial succession

increased diversity

continued co-adhesion

growth of micro colonies (1-7 days)

climax community 

1 week or older 

resident oral fluora

hydrogen peroxide

bacteriocins

STREPTOCOCCUS

Major hypothesis

ecological plaque hypothesis

ecological plaque hypothesis 

disease is the result of a shift in the balance of the resident microfluora driven by a change in local environmental conditions

white spot lesions

S. mutans

actinomyces

veillonella

dentinal caries and tubule infection

S. mutans

lactobacillus, actinomyces

bifidobacterium

prevotella

Root Caries

S. Mutans

actinomhyces

bifidobacterium 

what kinds of dentin are salvageable

demineralized dentin

sclerotic dentin

tertiary dentin

(caries affected (transparent zone))

what kind of dentin is not salvageable

zone of destruction (caries infected, discolored )

mono saccharides

glucose (brain and muscle)

fructose (liver)

galactose

dissacharides

lactose

sucrose

maltose

polysaccharides

starch

amylose

amylopectin 

sugar alcohols

non-cariogenic:

• xylitol

• mannitol

• sorbitol

• maltitol

• lactitol

• isomalt

tubule composition closer to DEJ

20,000 tubules/ mm2

closer to pulp

40,000 tubules / mm 2

what must happen before any adhesive procedure

teeth must be cleaned with OIL FREE PUMICE SLURRY 

• remove biofilm which has accumulated biofilm by day 3 

what will decalcify enamel

phosphoric acid

smear layer

• amorphous layer

• on top of the tooth

• created after drilling : bits of the fur, residual organic / inorganic debris

• 1-5 micrometers thick

which bur creates thinner smear layer

• carbide bur: less friction / heat

• smear layer is 2 micrometers

• diamond bur : 5 micrometers

smear is more of a problem on

DENTIN

smear must be removed / made permeable by 

PHOSPHORIC ACID 

most important part of restoration

Bonding

contact angel

angle adhesive makes with the tooth :

hydrophilic - lower contact angle : better because enamel and dentin contain water

micromechanical bond

penetration

permeation

polymerization - mechanical interlocking

chemical bond

not strongest part

chemical bonding to hydroxyapatite via ionic bonding/ salt formation

chemical bonding to collagen via covalent bonding

classifications of adhesive systems

1. etch and rinse

2. self etch

3. universal

4. self - adhesive

bifunctional monomers : 

HEMA

BIS GMA
G DMA

10 MDP 

TEG DMA

U DMA

bifunctional monomers are both

hydrophobic (resin bonding) and

hydrophilic ( enamel and dentin )

solvents

water, ethanol , acetone 

displaces water

reduces viscosity of co-monomer blend 

allows permeation into collagen matrix

adhesive/ bonding resin

bifunctional monomers + photoinitiators + fillers

most common filler in resin

silica / silicon dioxide SiO2

2 step etch and rinse

• primer and bond combined in single bottle

• must be applied twice (essentially 3 steps)

• high immediate bond strength

• decreases over time

• requires etch.

• higher concentration of solvent (50%)

self etch

1. two step (self-etching primer)

2. one step (all in one)

two step self etch

• etch and primer combined in one bottle

• primer is more acidic : pH : 1.25-1.9

• attempts to etch enamel and dentin simultaneously

• smear layer is not removed but more permeable

• bonding resin is hydrophobic and solvent free

• must etch enamel again (acidic primer doesn’t work on enamel )

nano - layering

10 MDP forms monomer-calcium salt with hydroxyapetic (chemical bond)

one step self etch

highest hydrophilic monomer content : acts as a semi-permeable membrane on dentin surface - causes water sorption (bad )

universal / multi mode adhesive

• single component light cured 

• can be applied as etch and rinse/ self etch, selective etch. 

• wet or dry 

• 10 MDP  makes interface resistant to degredation

• pH : 2-3

universal adhesive composition

bi functional monomer s: bisgma, tegdma, 10dmp , 1- mdp phosphate, hema 

• solvent + photoinitiators (CQ, silane) fillers 

common fillers

SiO2

BaO

Al2O3

NaSiF5

2SiO2

which mode do we use universal bond at USC

etch and rinse

type 1 etching pattern

dissolution of core of enamel rods

STRONGEST PATTERN

OCCLUSAL POSTERIOR

FACIAL ANTERIOR

type 2 etching pattern

dissolves periphery of enamel

INTERPROXIMAL 

Aprismatic enamel

Aprismatic enamel = enamel without rods, highly mineralized, outermost layer, more acid-resistant.

TYPE III

aprismatic enamel

mix of type 2 and 1

what shape does dentin take after etching

funnel

acid etch

35% phosphoric acid

removes 3-5 micrometers of dentinal tissue 

rinsing time

30 sec same as etching time

teeth should be shiny (not over dried )

MMP inhibitor

step 2.

matrix metallo proteinase

2% chlorhexidine

MMP

controls growth of DENTIN , eats collagen

awakened by etch

application of Chlorhexidine

only on DENTIN (where MMP’s are)

gentle scrubbing motion, 30 sec

gentle air dry (glossy)

universal adhesive

step 3 

4 layers - active application

air dry 5-15 sec

MUST APPEAR GLOSSY

light cure

final step:

20 sec

nano filler

SiO2

2-5 micrometers

incorporated within hybrid layer

essential in formation of bond to tooth structure 

HYBRID LAYER

normal salivary flow

1-2 ml / min

hyposalivary flow

< 0.5 ml/ minl=

caries risk assessment and documentation, LOW risk

D0601

caries risk assessment and documentation, MODERATE risk

D0602

caries risk assessment and documentation, HIGH / EXTREME HIGH risk

D0603