Cavity preparation class 1
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Transcript of Cavity preparation class 1
CLASS 1 CAVITY PREPARATION
Placed in pits and fissure lesions that occur in one or more of the ff:
a. Occlusal surfaces of molars and premolars
b. Occlusal 2/3 of buccal and lingual surfaces of molars
c. Lingual surfaces of anterior teethd. Any other unusually located pit or fissure
involved with decay
COMMON FEATURES
Outline form consists of smooth curves that avoid
occlusal eminences like cusps and ridges
Uniform depth of 1.5-2 mm from CSM
Or 0.5-1 mm from the DEJ
Proximal walls are perpendicular to the pulpal
floor or diverge pulpo-occlusalyProximal walls located 1.6-2
mm from the proximal surface
Round internal line angles
Buccal and lingual walls converge pulpo-occlusally
Butt joint or 90˚ CSM
Proximal walls follow contour of proximal surface
Pulpal floor is flat and usually perpendicular to the long axis of the tooth
DESIGN 1
PROCEDURE
Bucco-lingual cross-section
Mesio-distal cross-sectionInternal
Anatomy
DESIGN 1
Maxillary premolar“dumb-bell”-shaped
Mandibular 1st premolarCircular, resembling snake eyesMandibular 1st premolar“dumb-bell”-shapedMandibular 2nd premolarY-shaped
Mandibular 1st molarElongated
Mandibular 2nd molarElongated
Maxillary molarElongated
Maxillary molarMesial “kidney” shapedDistal “heart” shaped
LOCATION:Occlusal surfaces of molars & premolars
INDICATIONS:• caries penetration into dentin does not exceed 0.5mm-1 mm• involvement of enamel or pits and fissures will not widen more than ¼ intercuspal distance• good oral hygiene & low caries index• Areas of mouth with low cariogenic activity
DESIGN 2
LOCATION:Occlusal surfaces of molars & premolars
INDICATIONS:• caries cone in dentin extend 1 mm or more from DEJ• preparation involvement is more than ¼ ICD• as preventive measure in patients with high plaque & caries index• for teeth with intact cusps
Shapes similar to design 1 but there are more deviations from
shapes and less curved outline and greater surface dimensions
Margins similar to design 1 but closer
to cusp tips and crests of ridges
Bucco-lingual cross-section
Pulpal floor may have
different levels
If cavity margins are located in occlusal 1/3 of inclined planes of cusps, the buccal and lingual walls will have two planes
DESIGN 3LOCATION:Occlusal one- to two-thirds of facial and lingual surfaces of molars & lingual surfaces of anterior teeth
INDICATIONS:• the pit or fissure is decayed• used to eradicate pit or fissure as a prophylactic measure• involved pit is not connected w/ other surface(s) or lesions in the tooth• for invaginated teeth
GENERAL SHAPE: rounded, triangular, oblong, etc.INTERNAL ANATOMY: • All walls are joined together in a seemingly continuous fashion• Axial wall should be flat & make a definite acute angle with the continuous surrounding wall• If it is not conforming to enamel rod direction, it should be made in two planes
DESIGN 4LOCATION:Occlusal surfaces of molars and grooved part of their facial/lingual surface
INDICATIONS:• caries lesions at facial/lingual pits are connected to the occlusal surface• decay undermines facial/lingual marginal ridges• caries cones confined to the concavity of their grooves• cusps not undermined by backward decay
GENERAL SHAPE:same with design 1 & 2 facial/lingual part - parallelogram
INTERNAL ANATOMY
Mesio-distal cross-section
Bucco-lingual cross-section
DESIGN 5
LOCATION:Occlusal and facial and/or lingual surfaces of molars
INDICATIONS:• facial/lingual cusps undermined by backward decay• outline is not conducive to retention of restoration• caries cones in dentin exceed 1 mm from DEJ• foundation for cast restoration is needed
GENERAL SHAPE:same with design 2 facial/lingual part – parallelogram (larger)
INTERNAL ANATOMY
Mesio-distal cross-section
Bucco-lingual cross-section
DESIGN 6
LOCATION:Occlusal surfaces of molars & premolars as well as portion of facial, proximal or lingual surface in the form of a “table” of an entire cusp or a section of a cusp
INDICATIONS:• Portions or an entire cusp undermined by backward decay• caries leaves a cusp with a length-width ratio of 3:1 in functional cusp or 4:1 in non-functional cusp, and there is no interruption in the continuity of surrounding walls• caries leaves a cusp with a length-width ratio of 3:1 in functional cusp or 4:1 in non-functional cusp, and there is interruption in the continuity of surrounding walls• marginal ridge is crossed by a fissure to facial/lingual embrasures• foundation for a future cast restoration is needed• Class I occlusal lesion is continuous with a Class VI lesion
DESIGN 7
LOCATION:Occlusal, facial, and/or lingual surfaces of molars & premolars
INDICATIONS:• class 1 lesions with extensive carious involvement• Placement of internal boxes in the floor of preparation is impossible.• Pin/Post-Retained Restoration
DESIGN 8
LOCATION:Occlusal surfaces of molars & premolars, sometimes lingual surface of anterior teeth
INDICATIONS:• for endodontically treated teeth
FOR AMALGAM
CAVITY PREPARATIONs
1 2 3 4 5