Lecture 1, Operative Dentistry (Script)

8/4/2019 Lecture 1, Operative Dentistry (Script)

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Operative Dentistry Page 2

Operative Dentistry-

We start with a simple question: What is operative dentistry? Operative dentistry

is the art and science of the diagnosis, treatment and prognosis of teeth that do not

require full restoration or correction. Meaning that restorations inside the tooth (not

necessarily by carries), it could be a defect in the tooth unrelated to carries- also called

“Non-carious loss of tooth

structure” which could be as a

result of coronal defects of the

teeth, or defects caused by

carries. Operative dentistry

includes defects/restorations

inside the crown of the tooth=

Involved in INTRA-CORONAL

RESTORATIONS (any

restoration inside the tooth), any

restoration on the outside of the

tooth is called EXTRA-CORONAL RESTORATION.

Operative Dentistry also includes Prevention (we are also involved in preventing

the disease from occurring in the early stages) as well as preservation of the tooth

structure as well as interception of the disease (if you recall from cariology we can

interfere with the carious process and either slow it down or possible even reverse it at

a certain stage), and restoration (if it is too late to intercept and reverse the defect then

we must properly restore the tooth). So operative dentistry is basically based around:

Prevention, Intervention and restoration when required.




Classifications of Dental Carries:

**Note: we previously took the following classifications in “CARIOLOGY” so the

doctor read the slides very quickly.

Classification according to initial state of the tooth:

Primary (initial) Caries: The process attacks the tooth surface for the first time,

regardless of progression or extent. This refers to a tooth that was not previously

carious but was attacked by carries for the first time.

Secondary (Recurrent) caries: The process attacks the tooth at the margin or

margins of an existing restoration, regardless of extension or progression. In

secondary carries a new carious lesion attacks a previously restored area of the

tooth or a nearby surrounding area.

Classification according to the situation of the tooth:

Acute Caries: Involves a large number of teeth in the mouth, and destruction of

tooth structure is usually quiet rapid.

Chronic Caries: Much lower progression of the lesion, and the average lesion

size is smaller than in acute caries.

Active caries: Describe lesion that progressively destroys more tooth structure.

Arrested caries: Occurs when the active degradative process is interrupted or

ceases, an example of arrested carries is if someone has a proximal region and




an adjacent tooth was extracted exposure of the lesion to cleaning carious

lesion may arrest.

Classification according to Stage of

development of the lesion:

Incipient caries: The lesion is confined to enamel

and does not penetrate the DEJ. Also called White

Spot lesion when the Dentino-Enamel junction is

not reached (Lesion is confined to enamel = No undermining of enamel = no

cavity = remineralization of lesion is still possible).

Advanced caries:the other state of lesions in

teeth, when the lesion reaches or passes through

the DEJ and approaches the pulp. (if the lesion

reaches the DEJ then it is considered advanced).

Classification according to the Location of the Lesion:

Pit & fissure caries: originates in developmental irregularities, most often in the

occlusal surface of posterior teeth.




Smooth surface caries: In smooth surfaces of crown of teeth. (Smooth surfaces

of the teeth = Buccal, lingual, proximal)

Root caries: Does not originate in crown of teeth, but rather on the root structure.

Carries may sometimes originate in the crown and extend to the root, these

caries ARE NOT ROOT CARIES, for a carrie to be classified as a root carrie it

MUST ORIGINATE IN THE ROOT.

****NOTE: Pit & Fissure Caries as well as Smooth caries are considered CORONAL

CARIES.

Classification of a Cavity:

How is a cavity classified? A cavity is the hole that is drilled inside the tooth to

remove dental caries or a defect in the tooth or: Describes the defect in the tooth,

which is the result of caries.

“Cavity preparation (prepared cavity): Is the result of specific operative procedure

that has removed the caries or defect and shaped the tooth to receive and retain the




restorative material.” Acavity is the hole in the tooth caused by the defect (usually

carries) and Cavity preparation the hole we prepare inside the tooth with certain

geometry to retain the restoration (such as mechanical retention by sloping the walls

of the cavity in amalgam fillings).

“Restorative material:is the material that is used to restore the cavity, i.e.

Amalgam.”

“Restoration: The cavity preparation plus the restorative material.”

There must be a common language/understanding between dentists to easily

relay information about a cavity to each other; this is called Blacks Classification of

Cavities, named after G.V. Black (The father of operative dentistry, who placed the

basic principles of operative dentistry). Black placed a classification of cavities to be a

common language between dentists, these cavities where divided into 6 categories

(Class I, Class II, Class III, Class IV, Class V, Class VI).




Class I:class I originates in structural defects of the tooth such as pits and

fissures (usually on the occlusal surface of the tooth), preparation of a class I

cavity is called “class I preparation” and restoration of a class I cavity is also

called “class I restoration”. Any cavity found in the Lingual pit of Lateral Incisors is

also considered a class I cavity. (Class I does not define which surface the

structual defect is in, thus the lingual pit on the lingual surface of the tooth is

included).

Class II: Class II originates in the proximal (Mesial/Distal) surfaces of

MOLARS AND PRE-MOLARS. (in posterior teeth).




Class III: Class III cavities originate in the proximal surfaces (Mesial/Distal) of

Anterior teeth (Central, Lateral & canines), BUT DOES NOT INVOLVE the loss

or removal of the incisal angle/edge.

1 Class III cavities do NOT include the incisal edge of the tooth

Class IV:When a cavity involves the proximal surface of an anterior tooth alongwith the incisal edge of the tooth this is considered a Class IV (4) cavity.




Class IV:Class V cavities are found in the gingival/cervical (lower 1/3 rd) of any

tooth on the facial or lingual side (anterior/posterior), with the exclusion of Class I

pit/fissure caries.

**Note: the Buccal pit of the lower first molar is considered CLASS I , as well

as the palatal pit of the upper first molar- because these are NOT located in

the gingival third of the tooth.

Class VI: is a VERY RARE CASE, found located on the incisal edges of

canines and incisors, as well as the cusp tips of canines and posterior teeth.

.

.




Classification by Complexity of Cavity:

This type of classification depends on the number of tooth surfaces involved, and

it is not as commonly used as Blacks classification but you should still know it:

Simple: Involves only a single tooth surface (regardless of which surface it is).

Compound: Involves any two tooth surfaces (must be connected, otherwise its

considered two simple cavities not one complex cavity).

Complex: Involves three or more tooth surfaces.

Classification by Surfaces:

Prepared cavities or restorations take the name of the respective surfaces, for

example a cavity on the occlusal surface is called “O”, a cavity on two surfaces such as

the occlusal and Mesial surfaces is called “MO” (mesio-occlusal), involving three

services such as Mesial, Occlusal, and distal is called “MOD” (Mesio-Occlusal-Distal).




Components of Prepared Cavity:We also have names for the components of the prepared cavity including walls

floors and angles. The wall of the prepared cavity is the inclosing side of the prepared

cavity that takes the name of the adjacent surface of the tooth (Mesial wall/Distal wall),

the wall facing the distal side is the distal wall; the one on the mesial side is the mesial

wall… etc.

In class I cavities the surface facing the Pulp is called the PULPAL

FLOOR, in all other cavity classes the part facing the pulp is called

the AXIAL SURFACE.

Class II cavities are composed of an occlusal part and a proximal part, similar to

a step on a stairs, therefore it has both Pulpal and Axial internal walls. (you will

understand this better once we take it in the lab).

“Line angle: The line, or angle formed

when two walls of a prepared cavity

meet. It is named by combining the




names of intersecting walls, i.e. Linguopulpal line angle.” We have two

neighboring walls in the cavity for example the mesial wall and the pulpal floor,

the line that joins these walls together is called the Mesio-Pulpal line angle, in a

class two cavity it is possible to have a PulpoAxial line angle at the intersection

between the occlusal part of the cavity and the proximal part.

Point angle: when three walls meet they

will join in a POINT not a line, this point

angle will be named according to the

three walls forming it

(Linguoaxiogingival forming between

Axial-lingual-gingival walls).

Cavosurface angle: is a very important

angle in tooth restoration it is “The line

or angle formed by the junction of a

cavity wall with the unprepared surface

of the tooth”, or the angle formed

between the wall of the prepared cavity

and the unprepared tooth surface, this

angle will decide which restoration must be used on the cavity (in amalgam the

cavosurface angle must be 90 degrees).

Done by: Ali Al-Qudsi

Lecture 1, Operative Dentistry (Script)

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