cavity preparation basics

what is the conclusion of remineralization of white spot lesions

some white spot lesions are and aren’t remineralizable

are active (initial) or arrested (initial) lesions easier to remineralize

active initial lesions

minimally invasive cavity preparation is possible thanks to…

adhesive dentistry (bonded restoration)

amalgam or metal inlays require what type of preparation compared to and adhesive restoration

larger preparation- rely on mechanical support

the larger/more dental work you do on a tooth

the sooner you get to the end of the tooth

what is the GV back concept

the classifications of restorations (not the disease that is there)

what is a Class I restoration

restoration on one or more approximal surfaces added

what is a class II restoration

a class I restoration w one or more proximal surfaces added

what is a class III restoration

an approximal or proximal restoration in an anterior tooth; w/o incisal edge

what is a class IV restoration

a class III restoration involving the incisal edge

what is a class V restoration

a restoration on the B or L smooth surface, commonly in the gingival third

what is a class VI restoration

restoration of a cusp tip or incisal edge

what restoration class is this

class I

what restoration class is this

class II

what restoration class is this

class III

what restoration class is this

class IV

what restoration class is this

class V

what restoration class is this

class VI

classic principles of cavity preparation

• outline form

• resistance form

• retention form

• convenience form

• decay removal

• finish cavity walls

• clean cavity

how has the philosophies of surgical intervention changed over the last ~100 years

overtime we have become more and more conservative in cavity preparations- only do so when you absolutely have to drill

what was the ultra conservative “sealed restorations” introduced in the 80s

no prep, just bevel the enamel- don’t need to numb

what is the atraumatic restorative treatment that was introduced in the 90s

no rotary instrument, just scoop out decay and place GI

today, some preparation principals still apply but the traditional _______________________ is thought to be outdated

extension for prevention

____________________ angles are thought to be stress concentration points

sharp internal line angles- we want round now!

today, we want to rely on bonding, this is called…

adhesive dentistry

_________________ is essential placing margins in sound tooth structure

peripheral seal

you want to prioritize __________ health over complete caries removal and direct pulp cap

pulpal; want to preserve pulpal vitality

restorations are never as good as…

sound tooth tissue

redos of restorations usually result in…

larger restorations

more complex and bigger restorations have inc in cost, take more time, and are more likely to…

fail

what are the modern practice goals

• prevent

• reverse

• preserve

• retreat

• update

in terms of out modern practice goals, prevent…

initial lesion or progression of any lesion that exists

in terms of out modern practice goals, reverse…

lesions as possible, identify lesions early to maximize the opportunity for reversal

in terms of out modern practice goals, preserve…

as much tooth structure as possible for the long-term, remove as little tissue as possible

in terms of out modern practice goals, retreat …

only is needed, as little as possible, and w preservation as much as possible

in terms of out modern practice goals, update…

KEEP LEARNING

what are the cavity preparation factors

• which lesions

• what tooth and site/surface

• what material and restoration technique

what is the initial outline form

minimal surgical extension to eliminate defective tooth structure and provide a restorable surgical preparation; extent of disease and existing groove patterns are primary determinants of outline form

the initial outline form may be different depending on the…

restorative material

what is the caries-free DEJ outline form

should be caries free DEJ everywhere

what is the final outline form

clean periphery at the DEJ; accommodate the peripheral extent of the disease; may go beyond the initial form

the resistance form principals largely depend on…

the material that you are going to use

what is the resistance form principal

• eliminate undermined enamel that is susceptible to fracture

• avoid undermined cusps

  • enamel w no dentin support

• allow adequate thickness of restorative material to avoid fracture

what do you want to check before doing a filling preparation

occlusion

goal of retention form

create a surgical preparation that will mechanically retain the restoration; convergence vs divergence

convergence or divergence

convergent walls

convergence or divergence

divergent walls

composite restorations rely on ___________ (mechanical or bonding) techniques, amalgam restorations rely on _____________ (mechanical or bonding) techniques

bonding; mechanical

what is convince form

extending the outline to improve access to caries and ease material placement; avoid unnecessary extension

what are the principals for deep caries removal

use:

• visual

• hardness of dentin

• caries indicator dye

• clinical judgement

• knowledge of anatomy to consider pulp horn location

• pt age

what are the questions you should be asking to ensure pulpal protection

• how much dentin is left over the pulp

• how can i help remineralize caries-affected dentin

• was the pulp exposed, do we need IDP/DPC

what is DPC

placing the pulp cap directly in contact with the pulp tissue

what is IPD

placing the pulp cap not directly on the pulp tissue

what is routinely used for cleaning and disinfecting of the preparation

cavity cleanser such as 2% of chlorhexidine of di-gluconate

how are the chlorhexidine for cleaning the preparation vs the mouthwash different

mouthwash has detergent in them → contains no boning

when smoothing the outline form, you want to focus on what and why

the enamel walls and cavosurface margins; margins are frequently the site of restoration failure (restoration failure or recurrent decay)

good margin management is good ____________ dentistry

preventative

TERMINOLOGY PICTURES

what are the 4 external walls of a cavity preparation

• distal

• facial/buccal

• lingual

• gingival

what are the two internal walls of a cavity preparation

• pulpal

• axial

for composite, do you prefer sharp or round internal line angles

round

what did research show in the 1980-90s about a sharp internal line angles

where stress concentrates:

clinical load + viscoelasticity of dentin + stress concentration = higher risk of cusp fracture

what is a handpiece

a rotary device used to precisely modify enamel, dentin, and restorative mateials

what is a turbine

the part of the handpiece that turns the cutting bur; available in both air-driven and electrically-driven motors

advantages of electrical handpieces

• quiter

• more controllable rotations and torque

• no need for air compressors

disadvantages of electrical handpieces

• more expensive

• more sensitive parts

• heavier

what can the material of a bur be made of

• SS- stainless steel

• carbide

• diamond

• polishing: rubber, silicate

what are the parts of a bur

• shank

• neck

• head

what are the parameters of the head of a bur

• diameter

• shape

• length

• taper

what are the parameters of shanks of burs

• friction grip

• latch

• diameter

• length

when removing caries in dentin, what handpiece is recommended to use vs enamel

enamel: high-speed

dentin: slow speed

what is the speed range of a slow speed

6-10000

what can the speed up to in a highspeed

up to 200000

what are the types of heads on burs

• round

• pear

• straight fissure

• tapered fissure

• end cutting

bur type

round

bur type

pear

bur type

straight fissure

bur type

tapered fissure

bur type

end cutting

which bur would create sharp internal angles

straight fissure

funx of carbide bur

cutting

funx of diamond bur

grinding

why are diamond burs more commonly recommended nowadays over carbides

• smooth finish on teeth → better enamel margins

• less damage to cutting surface

• less burn on tooth and soft tissue

• better surface for bonding

• wide spectrum of roughness and cutting efficiency

how are the roughness of diamonds classifies

diamond grits and colors based on their coarseness

super course is what color and grit #

black;150 microns

coarse is what color and grit #

green = 125 microns

medium is what color and grit #

gray = 100 microns

fine is what color and grit #

red = 30 microns

extra fine is what color and grit #

yellow = 15 microns

ultra fine is what color and grit #

white = 8 microns

how is enamel finishing effected by coarse grit

get a smooth effect the finner bur you use