Crown
Anatomical crown:
Is the part of tooth covered with enamel. It doesn't change with age.
Clinical crown:
Is the part of crown that is only seen in oral cavity above the gum line. It increases with age.
Alveolar process, Alveolus, Crypt
Alveolar process:
The portion of jaw which serves for tooth support.
Alveolus(alveoli):
The bone of the tooth socket.
Crypt:
It is a bone surrounded cavity in the jaws in which development of tooth takes place.
Elevated landmarks:
1. lobe:
Is one of primary sections of formations in the development of the crown.
. :mamelon1.1.
is any one of three rounded protuberance found on incisal ridge of a newly erupted incisor tooth..
1.2. cingulum:
Is lingual lobe of anterior tooth.
1.3. cusp:
Is a divisional primary elevation on the occlusal third of posterior teeth, and incisal third of canines.
2. tubercle:
Is a smaller elevation on some portion of crown produce by excessive localized deposition of enamel.
3. ridge:
Is a linear elevation of the surface of the tooth, and is named according to its shape or location.
3.1. marginal ridge:
Linear elevation which forms the mesial + distal margins of occlusal surface of posterior teeth + lingual surface of anterior teeth.
3.2. triangular ridge:
Linear elevation which extends from tip of cusp toward the central portion of the occlusal surface of posterior. It is named for the cusp to which it belongs.
3.3.transverse ridge:
Made up of the union of two triangular ridges transversely.
3.4. oblique ridge:
Made up of the union of two triangular ridges obliquely.
3.5. cusp ridge:
Is a linear elevation which extends in a mesial + dustal dirctions from cusp tip.
3.6. cervical ridge:
Linear elevation on the cervical third of the buccal surface of premolars and molars.
3.7. labial ridge:
It is a linear elevation made by the middle lobe of the labial surface of canines.
3.8. buccal ridge:
It is a linear elevation made by the middle lobe of the buccal surface of premolars.
3.9. lingual ridge:
It is a linear elevation on the lingual surface of canines extending from the cingulum to the cusp tip and also found on the lingual surface of some premolars.
3.10. incisal ridge:
It is a linear elevation made by the incisal portion of a newly erupted anterior tooth.
Depressed landmarks
1. Developmental Groove :
It is a deep linear depression in the occlusal surface and may extend buccaly , lingually or mesially denoting the line fusion of primary lobes (يعني يبين الخط حق اندماج اللوبز الأساسية )
2. Supplemental Groove :
It is a shallow linear depression on the occlusal surface which does not demarcate the line of lobe fusion , but represents a branch from the developmental groove.
3. Pit :
Small pinpoint depression located at the junction of developmental grooves or at terminals of these grooves.
4. Fissure :
It is a deep cleft or defect on the occlusal or buccal surface resulting from linear imperfect fusion of enamel of the dental lobes.. found in the place of the developmental grooves.
5. Sulcus :
It is a long tent shaped space or valley on the occlusal surface running between the cusps and its inclined surface meeting centrally.
6. Fossa :
It is a small depression or concavity on the lingual surface of anterior teeth and occlusal surface of posterior teeth.
6.1. lingual fossa :
A broad , shallow depression on the lingual surface of an incisor or canine.
6.2. triangular fossa :
A shallow pyramid shaped depression on the occlusal surface of the posterior teeth.
6.3. central fossa , maxillary molars :
A relatively broad , deep angular valley in the central portion of the occlusal surface of maxillary molar.
6.4. central fossa , mandibular molars :
A relatively broad , deep angular valley in the central portion of the occlusal surface of mandibular molar.
تعاريف متفرقةDental formulae:
It is denomination and number of tooth including one side of mooth.
Dental tissue:
Enamel, dentin, cementum, pulp + peridontium
Line angle:
A line where 2 surfaces of tooth meet.
Point angle:
A point where 3 surfaces of tooth meet.
| Line angle | Point angles | ||
| Anterior (6) | Posterior (8) | Anterior (4) | Posterior (4) |
| LB – i | LG – O | M- LB-i | M – B – O |
| LG – i | B – O | M -LG-i | M – LG – O |
| M – LG | M – O | D – LB – i | D – B – O |
| D – LG | D - O | D – LG - i | D – LG – O |
| M – LB | M – B | | |
| D - LB | D – B | | |
| | M – LG | | |
| | D – LG | | |
Development of dentition ( calcification + eruption )
Sequence of eruption of deciduous :
A àB à D àC à E
Sequence of eruption of permenant:
1st molar (6 y) à lower central +lateral incisors à upper central incisor à upper lateral incisor à lower canine à 1st premolar à 2nd premolar à upper canine à 2nd molar à 3rd molar
Dentition ( according to sequence of persistence of deciduous + permanent in oral cavity)
1. 1ry dentition (6Mà5Y +or- 9M)
2. Mixed dentition ( 6Y à 10Y +or-9M)
3. Permanent dentition (11Yà)
Classification of teeth according to:
| arch | Appearance + persistence | Function + form | |||
| 1.maxilary (fixed tooth) | 1. deciduous(1ry) | Ant. teeth | Post. Teeth | ||
| 2. mandible (movable tooth) | 2. permanent | Incisor (incise+cut) | Canine "cuspied" (hold, grasp, pierce, tear) | Premolar (hold, tear rather than incisor) | Molar (chewing, grinding) |
Dental formulae (انتبهوا مو هي نفسها الـ occlusion formula )
Deciduous:
I 2/2 C 1/1 M 2/2= 10 teeth on either side
----> 20 teeth ( no premolars)
Permanent:
I 2/2 C 1/1 P2/2 M3/3 = 16 teeth on either side
----> 32 teeth
Basic terminology for morphology
1. Single rooted tooth
2. Double rooted tooth-----à have bifurcation area + root trunk
3. Multi-rooted tooth -----à have trifurcation area + root trunk
Surfaces of teeth
| Facial | lingual | proximal | Masticatory |
| LB+ B | palatal | M+D | I+O |
Mixed dentition(deciduous+permanent teeth)
when deciduous teeth:
1. ما تخدم حاجة الفرد
2. are lost and replaced by permanent teeth(larger+stronger+more in number)
Exfoliation: 5-12 Y + permanent start to erupt.
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