Cavity preparation class 1

General principles and designs of cavity preparation for Class I caries. By Ma. Hermie Culeen Barapon

1. CLASS 1 CAVITY PREPARATION Placed in pits and fissure lesions that occur in one or more of the ff: Occlusal surfaces of molars and premolars Occlusal 2/3 of buccal and lingual surfaces of molars Lingual surfaces of anterior teeth Any other unusually located pit or fissure involved with decay

2. 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-occlusaly Proximal 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

3. DESIGN 1 PROCEDURE Bucco-lingual cross-section Mesio-distal cross-section Internal Anatomy

4. DESIGN 1 Maxillary premolar “dumb-bell”-shaped Mandibular 1st premolar Circular, resembling snake eyes Mandibular 1st premolar “dumb-bell”-shaped Mandibular 2nd premolar Y-shaped Mandibular 1st molar Elongated Mandibular 2nd molar Elongated Maxillary molar Elongated Maxillary molar Mesial “kidney” shaped Distal “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

5. 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

6. DESIGN 3 LOCATION: 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

7. DESIGN 4 LOCATION: 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

8. 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

9. 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

10. 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

11. DESIGN 8 LOCATION: Occlusal surfaces of molars & premolars, sometimes lingual surface of anterior teeth INDICATIONS: for endodontically treated teeth

12. FOR AMALGAM CAVITY PREPARATIONs 1 2 3 4 5