➡️ Morphology of Fissures:
Based on morphological alphabetical description of shape – 4 types:
- V + U (Self-cleansing)
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
Retention of food debris & microbes
Fermentation of food by microbes
Formation of Acid
➡️ 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
References: Wheeler’s Textbook, Google images