Zusammenfassung der Ressource
TOOTH MORPHOLOGY
- DECIDUOUS AND PRIMARY DENTITION
- By 3yrs old deciduous dentition is complete
- By 6yrs 1st permanent molars appaear
- Complete permanent dentition by 18yrs
- Only permanent Incisors, Canines and premolars have predecessors
- During jaw growth spaces develop interdentally in decid dentititon - Primate spaces
- Decid incisors, canines, molars replaced at 7-13yrs
- 3 additional perm molars appear at 6,12, 18yrs
- TOOTH ERUPTION
- The process whereby a tooth moves from its developmental space to its functional position
- The main direction is axial but movement also occurs in other planes
- Rate of eruption is at its greatest at crown emergance. Rates differ according to tooth
- As the tooth approaches the oral cavity the overlying bone is resorbed
- Eruption sequence of Decidous - ABDCE. Mandibular before Maxillary
- Eruption sequence of permanent
- Mandibular - 61234578
- Maxillary - 61245378
- Completion of the root takes place 2yrs after eruption
- DIFFERENCES OF DENTITIONS
- Decid are smaller
- lighter in colour
- crowns are more bulbous
- More slender and root canals v fine
- Roots more divergent to allow perm dent space
- Enamel less hard than perm
- Ratio of pulp and crown is much smaller in decid
- FUNCTIONS OF DENTITION
- mastication
- Speech
- Aesthetics
- Maintains Profile
- Maintains space for Perm dentition
- MAX 1st PERM INCISOR
- Widest mesiodistally
- Wedge chisel shaped
- Single root, distal curvature
- 2 Labial grooves give rise to mamelons
- Distally rounded
- Mesially straight
- MAX 2nd PERM INCISOR
- Shorter and narrower than 1st
- Distal angle more rounded
- Well marked Cingulum
- Groove cingulum and lingual fossa - prone to caries
- May be congenitally missing
- Grooves on mesial and distal aspects of the root
- MAX PERM CANINE
- Prominent tooth (eye tooth)
- Longest root, triangular in section, wider labially than palatally
- Stout barrel shaped
- Distal slope of cusp longer than mesial
- Marked cingulum palatally
- MAX 1st PREMOLAR
- Larger crown than U 2nd premolar
- 2 roots - 1 buccal and 1 palatal
- Buccal cusp higher than palatal
- Marked depression on mesial aspect (Canine Fossa)
- Immediately below contact with canine - can be hard to remove calculus here
- MAX 2nd PREMOLAR
- 1 Root
- No canine fossa
- Root may have deep groove mesially and distally but no bifurcation
- Cusps are more equal height
- Mesial slope of cusp shorter than distal
- MAX 1st PERM MOLAR
- 3 roots, mesiobuccal, distobuccal, palatal
- Palatal root is largest and most divergent
- MB and DB roots curve towards each other
- MP cusp is largest and joined to DB cusp by Oblique Ridge
- Fissure pattern H shaped
- Occ crown is Rhomboid shaped
- Cusp of Carabelli - 5th cusp, present palatally 60% of 6's
- MAX 2ND MOLAR
- Rhombic occ outline
- Roots less divergent
- MAX 3RD MOLAR
- Triangular occ outline
- Smallest max molar
- congenitally missing or no eruption
- Roots short and fused, curve distally