➡️ Morphology of Fissures:

Based on morphological alphabetical description of shape – 4 types:

1. V + U (Self-cleansing)
2. U
3. K

Note: Pit & fissure with high steep walls & narrow bases are more prone to caries.(Developmental faults)

Occlusal fissures: Deep invagination of enamel, described as broad/narrow funnels, constricted hour glasses, multiple invaginations with inverted Y-shaped divisions & irregularly shaped.

Deep and narrow Pit & Fissure

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Retention of food debris & microbes

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Fermentation of food by microbes

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Formation of Acid

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Caries

➡️ The lesions develops from attack on their walls.

• Cross section: Inverted “V” (A narrow entrance & wider involvement closer to DEJ)
• Therefore, Greater no. of Dentinal Tubules are involved.
• Early dentin involvement – When enamel at bottom of Pit & fissure is thin.

Caries when occur at Pit & Fissure follow direction of ENAMEL RODS

ENAMEL LAMELLAE – Initiation of Caries

The Initial Carious lesion of Enamel:-

• Clinical View:

• Visual Changes – Chalkiness, yellow/brown/black discoloration.
• Soft & ‘catch’ a fine explorer point.
• Enamel bordering them is opaque bluish white & undermined ➡️ Lateral spread of caries at DEJ
• Sign on stained tooth (Brown P/F)
• Newly erupted teeth – underlying decay; Older: Arrested lesion

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References: Wheeler’s Textbook, Google images