Operative II Lecture ( 2 ) Dr Ashraf Dr SaGeD LoAi

Cavity Classification and Nomenclature Note that Line of treatment depend on patient interest

Terminology

Cavity is a defect in hard tooth structure. Cavity It is surgical (Mechanical) excision of the lesion in hard tooth structure

and modification in the cavity to accept the restoration and be retentive

to this restoration and resistant to fracture.

Cavity preparation

Cavityمش Cavity preparationبتعملوا عشان كدا انتم ف السكاشن

Classification of cavities 1. Anatomical classification.

2. Black's classification.

3. Numerical classification.

4. Mount؛s Site Stage classification.

Anatomical classification (According to site of caries)

Pit and fissure

From development of lobes: - 1. Incomplete union of grooves very shallow U shape defect (fissure) Food impaction.

2. Incomplete union of grooves with marginal ridge pit

Smooth surface

1. Inter proximal areas between teeth ( below contact areas) 2. Buccal and lingual below height of contour

So you must use floss between your teeth

Black's classification (Cavity and cavity preparation) 1. Most common classification up till now 2. Not help in treatment plan or prognosis

Class I

All pit-and-fissure preparations (Anterior + Posterior)

These include preparations on: 1. Occlusal surfaces of premolars and molars. 2. Occlusal two-thirds of the facial and lingual surfaces of molars. 3. Palatal pits of maxillary incisors.

Class II Preparations involving the proximal surfaces of posterior teeth

Class III Preparations involving the proximal surfaces of anterior teeth that do not include the incisal angle

Class IV Preparations involving the proximal surfaces of anterior teeth that include the incisal edge

Class V Preparations on the gingival third of the facial or lingual surfaces of all teeth (Anterior +

Posterior)

Class VI Preparations on the incisal edges of anterior teeth or the occlusal cusp tips of posterior teeth

Congenital defects or any abnormal location

Operative II Lecture ( 2 ) Dr Ashraf Dr SaGeD LoAi

Numerical classification (According to number of surfaces involved) MCQ

1. Combined with Black classification 2. help in prognosis

Notes

Simple class I Occlusal (Good prognosis)

Compound class I Buccal with occlusal or lingual with occlusal (poor prognosis)

Complex class I Buccal + Occlusal + Lingual (very poor prognosis)

There is complex class IV only

Class VI simple + compound + complex

Simple One surface Ex. Simple class I,II,III and V

Compound Two surfaces Ex. Compound class I,II and III

Complex More than two surfaces Ex complex class I,II ,III and IV

Classification by Mount and Hume 1. More descriptive 2. Help in line of treatment 3. Site Stage classification (Si/Sta)

3 sites 5 sizes Site 1

Pits, fissures and enamel defects on occlusal surfaces of posterior teeth or other smooth surfaces

Size 0 Lesion with no surface discontinuity may not require surgical intervention.

Size1 Minimal involvement of dentin just beyond treatment by

remineralization alone.

Site 2 Proximal enamel immediately below areas in contact with adjacent teeth

Size2 Moderate involvement of dentin.

Following cavity preparation, remaining enamel is sound, well supported by dentin and not likely to fail under normal occlusal load.

The remaining tooth structure is sufficiently strong to support the restoration.

Site 3 The cervical one third of the crown or following gingival recession, the exposed root

Size 3 The cavity is enlarged beyond moderate.

The remaining tooth structure is weakened to the extent that cups or incisal edges are split, or are likely to fail or left exposed to occlusal or incisal load.

The cavity needs to be further enlarged so that the restoration can be designed to provide support and protection to the remaining tooth structure.

Size4

Extensive caries with bulk loss of tooth structure has already occurred.

Operative II Lecture ( 2 ) Dr Ashraf Dr SaGeD LoAi

Blacks Rules 1. Rule I: Walls named as the corresponding tooth surface. 2. Rule II: Walls over the pulp and perpendicular to long axis called pulpal. 3. Rule III: Walls over the pulp and parallel to long axis called axial. 4. Rule IV: Line angle is meeting of 2 surfaces and named from the two walls 5. Rule V: Point angle is meeting of 3 surfaces and named from the three walls

Cavity preparation Nomenclature

Internal wall It is the prepared surface that does not extend to the external tooth surface

1. Axial wall the axial wall is the internal wall parallel to the long axis of the tooth.

2. Pulpal floor the pulpal wall is the internal wall that is perpendicular to the long axis of the tooth and occlusal of the pulp.

External wall The external wall is the prepared surface that extends to the external tooth surface

Such a wall takes the name of the tooth surface (or aspect) that the wall is adjacent to (Like buccal, lingual, mesial and distal)

1. Enamel wall the enamel wall is that portion of a prepared external wall consisting of enamel 2. Dentin wall the dentinal wall is that portion of a prepared external wall consisting of

dentin, in which mechanical retention features may be located

Line angle ferent orientation along a lineplanar surfaces of diftwo A line angle is the junction of

1- Definite That is we choose 2- Indefinite

3- Sharp Stress concentration area

Point angle rfaces of different orientationsu planar threeis the junction of The point angle

Classموضع سؤال مهم جدا يسألك عن العدد فى كل

Operative II Lecture ( 2 ) Dr Ashraf Dr SaGeD LoAi suface margin-Cavo

It is the external margins of the cavity

suface angle-Cavo It is the angle formed between the cavity wall and the external too surface (it is interior angle inside tooth structure).

Reflect edge thickness

CSA of amalgam is putty joint = 90 to avoid fracture of amalgam and tooth but in proximal according to case

CAS of percaline (ceramic) is putty joint = 90

CAS of cast metal = 160

Isthmus It is the portion of the compound and complex cavities that joining the two portions.