Developmental anomalies of tooth
Mesiodens: A small supernumerary tooth that forms between the central incisors (.15-1.9% occurrence)
Distomolars, paramolars, 4thmolars: extra molars
Gemination or twinning: results from the splitting of a single forming tooth bud, separation is incomplete (larger crown, one normal root).
Fusion: joining of 2 root buds and involves dentin (larger crown, 2 separate roots).
Hutchinson’s teeth: screwdriver shaped, taper from cervical to incisal edge. From prenatal syphilis (also cause of mulberry molars).
Concrescent: After development 2 teeth fuse by Cementum only, usually due to close proximity of root during eruption (usually affects Mx incisors).
Tuberculum intermedium: extra cusp in middle in tooth
Tuberculum sextum: extra cusp on distal side of tooth
Taurodontism: no tapering of root, block shaped
Shovel-shaped incisors: pronounced cingulum
Dens in dente: “tooth within a tooth” usually Mx lateral incisors (in cingulum), a mass of enamel in dentin. Often peg shaped.
Ankylosis: outside of occlusion, fused directly to alveolar bone, breaking down of periodontal ligaments.
Transposition: 2 teeth switched
Abfraction: results from tooth bending, lesions from separation of enamel rods.
Enamel pearl: small, rounded formation of extra enamel on tooth
Micro vs macro dentia: abnormally small or large teeth
Hypercementosis: An overgrowth of cementum on the root of a tooth possibly caused by localized trauma or inflammation, metabolic dysfunction, or developmental defects.