operative dentistry

main goals of operative dentistry

1. Diagnosis

2. Prevention

3. Treatment

diagnosis

the use of various aids (such as radiographs, instruments, medical history, dental history) to determine etiology and appropriate treatment

primary prevention

prevention of the disease prior to evidence of its occurance

secondary prevention

prevention of a recurrence of the disease or an incipient lesion from progressing to a more advanced condition

primary goal of dental provider

prevention of lesions (not treatment)

tooth preparation

the mechanical alteration of a defective, injured, or diseased tooth such that the placement of restorative material re-establishes normal form and function including esthetic corrections where indicated

types of tooth preparations

conventional preparations, modified preparations

conventional preparations

precise procedure with specific depths, wall forms, and marginal configurations

- dental amalgams, cast metal restorations, ceramic restorations

modified preparations

less precise design requirements

- composite resins

types of lesions (7)

-caries

-abrasion

-erosion

-attrition

-fracture

-developmental defects

-abfraction

caries

- non-communicable disease that results in the breakdown of enamel and dentin due to bacterial invasion

- most common type of lesion

etiologic factors of caries

- acid producing microbes (lactic acid)

- susceptible tooth structure

- carb rich diet

abrasion

- pathogenic wearing of tooth structure via abrasive agents like excessive toothbrushing

- usually produces a V shaped defect

- surrounding gingival tissues are usually healthy

erosion

chemical dissolution of tooth structure

- most common on facial surface in gingival third

- usually not associated with caries

- produces a rounded or saucered defect

- surrounding gingival tissues usually healthy

attrition

physiologic wear, generally due to occlusal forces

- affects occlusal and proximal surfaces

fracture

usually due to trauma

- may be caused by excessive or improperly directed occlusal forces

developmental defects

restored to remove caries, to prevent carious involvement or for esthetic considerations

abfration

non-carious lesions thought to have a combined cause of abrasion and occlusally induced tooth flexure

objectives of tooth preparation

- remove defects/ faults/ carious structure (+unsupported enamel)

- pulpal protection

- extend as conservatively as possible

- protect the restoration and remaining tooth structure

- esthetics and function

primary caries

original carious lesion of the tooth

secondary caries

Occurs at the junction of a restoration & tooth... often progresses under the restoration

residual caries

Caries that remain in a completed tooth preparation

incipient caries

Reversible, enamel surface is intact

cavitated caries

Irreversible, enamel surface is broken

Armamentarium

a collection of resources available or utilized for an undertaking or field of activity; especially the equipment, methods, and pharmaceuticals used in medicine

electric rotary instrument

- 200,000 RPM

- increased torque (little or no slowing as load is increased)

air driven rotary instrument

- 400,000 RPM

- decreased torque (may slow and/or stop if load is increased)

uses for slow speed

- finishing and polishing restorations/ teeth

- prophylaxis

- caries excavations close to pulp

- lab procedures

High speed handpiece

- 200k-500k rpm

- increaed cutting efficiency

- decreased vibration

- fiber optic lighting

- water spray

uses for high speed

cutting enamel and dentin

removing old restorations

why not only use slow speed?

- it is not as efficient

- not as comfy for patient or operator

- needs a heavy hand

- excessive vibration

bur shank

fits into handpiece, can be latch or friction grip

carbide bur

blade cutting

- better for end cutting, produce lower heat, and have more blade edges for cutting

diamond bur

more effective than carbides for intracoronal and extracoronal tooth preparations, beveling enamel margins, and enamelplasty

how carbides cut

shear off or cause brittle fracture of tooth structure

- blade edges fracture off pieces of the surface being cut

how diamonds cut

abrade away tooth structure

- hard particles repeatedly scratch the surface deforming it, work hardening or weakening it, and finally wearing it away

concentricity

symmetry of bur head and preciseness of spin

run out

center of rotation of bur head is not symmetrical

- caused by bur head that is off center, bent bur neck/ shank or defective handpiece

- produces vibration and lack of cutting control

rake face

toward the direction of cutting

clearance face

facing away from direction of cutting

flutes

spaces between blades, remove debris

- increases cutting efficiency by removing debris

rake angle

MOST IMPORTANT

-negative rake angles allow cutting edge to sweep across surfaces without "digging in" minimizing fracture of the bur

- the rake angle is said to be "negative" when the rake face is ahead of the radius from the cutting edge to the axis of the bur

edge angle

Larger edge angles provide more bulk behind the cutting edge minimizing fracture of bur, usually 90 degrees on carbide burs

increased clearance angle…

Increased clearance angle causes a decreased edge angle

Increased clearance angle decreases friction on tooth and facilitates cleaning away of tooth debris

Need for restorative Summary:

A variety of reasons

• __

• __ and or _ of previous ?

• __ tooth structure, or _

• __ defects: restore _ and/or ? of a ? tooth

• In conjunction with other restorative procedures

Caries

Replacement, repair of previous restorations

Missing, fracture

Congenital, form, function, malformed

Need for restorative Dentistry:

Replacement and or repair of previous restorations:

• __ _ contacts or poor ?

• Gingival __, or _

• __ or (?) _

• Poor ?

Improper proximal, embrasure forms

Overhangs, ledges

Defective (open) margins

esthetics

5 Factors that affect tooth prep

diagnosis, dental anatomy, patient factors, conservation of tooth structure, restorative material considerations/factors

Preparing a tooth for restoration:

• In order to place a restoration, we must first __?

• Remove ?

• Prepare a proper “__ _,” to retain the restorative (?) ?

• Each material has different requirements for ?

• Preservation of ?

prepare it

decay

outline form, filling material

prep design

Healthy tooth structure

Caries Definition:

Microbiologic __ that results in ? ?, or ? or ? tissues of the teeth

disease, localized dissolution, destruction, calcified

Episodic caries:

? and ?

Demineralization and remineralization

Hand held instruments are designed to cut ?

They cut __ _ (ie ? or ?)

They cut ___ _ (ie ? ?)

Intraorally

tooth structure, dentin enamel

Restorative materials (carve amalgram)

Basic elements of hand instruments

1. __: to ?

2. __ to ?

3. __ to ?

handle (shaft), to hold

Blade, to cut

Shank: to connect handle to blade

Used to ? Which class?

hatchet: used to plane proximal walls and gingival seats of class II cav preps

What is it?

used to __ into cavity prep

The part equivalent to the blade is the ?

The end of the ^ is the ?

Plugger/condenser

pack restorative material

nib, face

WHat is it?

Used to __ restorative materials

Ball burnisher, burnish

It is the ___ instrument

Plastic filling: composite resin placement

What cassette do we use in dent disease?

CL-OP (clinical operative cassette)

two alternatives to rotary instrumentation

Laser + air abrasion

One component device is a __ speed, while two+ is?

high, slow

Slow speed Hand-piece

• Vibrates more or less than high speed?

• better __ than high

• Higher or lower RPM

• High or low torque?

More, tactile, lower, high

Match: Effectiveness, efficiency

1. Amount of energy utilized in cutting, not wasted as heat or vibration

2. Amount of structure removed per unit of time

1. Efficiency

2. Effectiveness

Carbide burs are made of __ carbide power and _ molded under heat and vacuum in a process called ?

tungsten, pressure, sintering

Match: Round, Inverted, Pear shaped

1. Placing retentive undercuts in preparations, flattening floors

2. Initial entry into tooth, extension of prep, prep retentive features, caries removal

3. Good for amalgam, composite prep, versatile

1. Inverted

2. Round

3. Pear shaped

Amalgam tooth preparations or any prep that requires parallel walls, the __ fissure is used

Indirect restorations and divergent walls: __ fissure

straight, tapered

Each blade has 2 Sides:

• __: faces?

• __: faces?

Flutes: __ between ?, remove ?

Rake, toward cutting

Clearance: away

Spaces blades, debris

Rake, edge, clearance

The blade __ and _ determines its use and function

shape, design

Match: The bur designs that influence cutting

Spiral Blades, Cross cut blades, flutes, number of blades

1. larger blade number produces __ surfaces at _ speeds

2. Increase cutting efficiency at high speeds

3. Increase cutting efficiency by removing debris

4. Increase cutting efficiency and increase surface roughness at low speeds

1. Number of blades: smooth, low

2. Spiral

3. Flutes

4. Cross cut

In addition to the shank, head, and neck, diamond burs consists of three parts

metal blank, powdered diamond abrasive, metallic bonding agent

The ___ __ _ holds the power on the blank of the diamond bur

Metallic bonding agent

Longer lasting: carbide or diamond

More efficient overall for cutting tooth structure: carbide or diamond

In diamond, the cutting effectiveness and applications are determined by the ____ and __ of diamond _

Diamond, diamond, size, spacing, particles

Diamond:

__ determines amount and pressure of particles in contact with surfaces to be cut

The particles __ _ structure to remove tooth structure

spacing, dig into

The ___ the particles of diamond, the ___ the prep

Which is Smaller? carbide or diamond?

Which has more shapes?

finer, smoother

Carbides

Diamonds