Tooth morphology-3

Questions	Answer
The formation of each centre of cusp formation proceed till they	Coalesce
Signs of demarcation between the formation of each developmental lobe is by the	Developmental groove
Formation of tooth is said to be completed when tooth	Apex is formed
Root formation of deciduous teeth is complete within	36 - 48 months after tooth eruption
The most unstable teeth in the deciduous dentition are the	Second molars and maxillary incisors
The highest peak of caries attack is observed during	13 years
The susceptibility of dental caries is a function of	Exposure time; Oral environment; Morphological type and surface of teeth
The period of exfoliation of deciduous dentition is the	7th – 12th year
The crown of deciduous mandibular first molar resemble the crown of	The crown of deciduous mandibular first molar does not resemble the crown of any teeth – deciduous or permanent dentition
As compared to the permanent dentition, the deciduous anterior teeth have	Prominent cervical ridge; Narrower cervical margin; Flared roots in the posterior teeth
As compared to the permanent teeth the buccolingual diameter of the deciduous teeth is	Less
As compared to the permanent teeth the ratio of crown length to mesiodistal width, the deciduous teeth is	Higher
As compared to permanent dentition, the tooth length to root length of anterior deciduous teeth appear	Narrower and longer
The purpose of flaring in the deciduous molar roots is (are)	To accommodate developing permanent premolars
Crown and root of deciduous molars at the cervical portion are	Slender mesiodistally
As compared to permanent dentition, the cervical ridges in deciduous teeth are	More pronounced
As compared to permanent dentition, the occlusal surface in deciduous teeth are	Narrower
As compared to permanent dentition, the pulp horns and chambers in deciduous teeth are	High and large. Though it is observed in all teeth, it is obvious in mesial pulp horns of all teeth.
The mesiodistal diameter is greater than the cervicoincisal length in	Deciduous maxillary central incisor; Permanent maxillary central incisor; Permanent molars. For the permanent maxillary central incisor the mesiodistal diameter is lesser than the cervicoincisal length.
As compared to permanent maxillary central incisor, the tooth length to root length of anterior deciduous maxillary central incisor have	Increased root length

Tooth morphology-3

Questions

1. The formation of each centre of cusp formation proceed till they
2. Signs of demarcation between the formation of each developmental lobe is by the
3. Formation of tooth is said to be completed when tooth
4. Root formation of deciduous teeth is complete within
5. The most unstable teeth in the deciduous dentition are the
6. The highest peak of caries attack is observed during
7. The susceptibility of dental caries is a function of
8. The period of exfoliation of deciduous dentition is the
9. The crown of deciduous mandibular first molar resemble the crown of
10. As compared to the permanent dentition, the deciduous anterior teeth have
11. As compared to the permanent teeth the buccolingual diameter of the deciduous teeth is
12. As compared to the permanent teeth the ratio of crown length to mesiodistal width, the deciduous teeth is
13. As compared to permanent dentition, the tooth length to root length of anterior deciduous teeth appear
14. The purpose of flaring in the deciduous molar roots is (are)
15. Crown and root of deciduous molars at the cervical portion are
16. As compared to permanent dentition, the cervical ridges in deciduous teeth are
17. As compared to permanent dentition, the occlusal surface in deciduous teeth are
18. As compared to permanent dentition, the pulp horns and chambers in deciduous teeth are
19. The mesiodistal diameter is greater than the cervicoincisal length in
20. As compared to permanent maxillary central incisor, the tooth length to root length of anterior deciduous maxillary central incisor have

Answers will be posted tommorrow

Tooth Morphology-2

Questions	Answer
On the occlusal surface of posterior teeth triangular fossa are found along the	Proximal to marginal ridge
If found, in anterior teeth, the triangular fossa is usually found on the	Palatal surface at edge of lingual fossa
A long valley like depression in any surface of tooth often between ridges/ cusp is the	Sulcus
A sulcus at its junction of its incline usually has a	Groove
A shallow line between primary parts of a crown or a root is the	Developmental groove
A shallow line on any surface of tooth that does not demarcate primary parts of  a tooth is the	Supplemental groove
The pinpoint depressions along the developmental grooves are the	Pits
Lobes are primary section of formation in the development of crown and are represented by the	Cusp; Mamelons; Cingulum
The number of line angles and point angles in an anterior teeth	6; 4
The number of line angles and point angles in a posterior teeth	8; 4
The important indicator(s) of dental age used clinically often is (are)	Calcification extent; Level of root formation; Eruption of teeth
The evidence of calcification for a deciduous dentition is observed by	4th month of intra uterine life. Near the end of the 6th month of intrauterine life all deciduous teeth would have began their development.
The human deciduous mandibular central incisors erupt by	6 months
The human deciduous canine erupt by	16 months
The general order of deciduous teeth eruption is	Central incisor, lateral incisor, 1st molar, canine, 2nd molar
The deciduous teeth is use for approximately for	5 to 11.5 years
Second permanent tooth to erupt in the oral cavity is	Mandibular central incisor. First molar is the first permanent teeth to erupt in the oral cavity.
The follicles of developing anterior teeth are positioned	Lingual. The developing premolars are placed within the bifurcation of deciduous molars.
The general eruption schedule of permanent dentition in mandible is	6123457. The maxillary schedule is 6124537
The teeth that is subject to many anomalies and variation in the form is the	Permanent third molars

Tooth morphology-2

Questions

1. On the occlusal surface of posterior teeth triangular fossa are found along the
2. If found, in anterior teeth, the triangular fossa is usually found on the
3. A long valley like depression in any surface of tooth often between ridges/ cusp is the
4. A sulcus at its junction of its incline usually has a
5. A shallow line between primary parts of a crown or a root is the
6. A shallow line on any surface of tooth that does not demarcate primary parts of  a tooth is the
7. The pinpoint depressions along the developmental grooves are the
8. Lobes are primary section of formation in the development of crown and are represented by the
9. The number of line angles and point angles in an anterior teeth
10. The number of line angles and point angles in a posterior teeth
11. The important indicator(s) of dental age used clinically often is (are)
12. The evidence of calcification for a deciduous dentition is observed by
13. The human deciduous mandibular central incisors erupt by
14. The human deciduous canine erupt by
15. The general order of deciduous teeth eruption is
16. The deciduous teeth is use for approximately for
17. Second permanent tooth to erupt in the oral cavity is
18. The follicles of developing anterior teeth are positioned
19. The general eruption schedule of permanent dentition in mandible is
20. The permanant teeth that is subject to many anomalies and variation in the form is the

Answers will be posted tomorrow

Differences in hard tissues

Difference between acellular and cellular cementum

	Acellular cementum	Cellular cementum
Commonly seen in	Cervical and middle third of root	Apical third of root
Position of cells	No cells	Lacunae and canaliculi containing cementocytes and their processes
Border with dentin	Not clearly demarcated	Clearly demarcated
Rate of development	Relatively slow	Relatively fast
Incremental lines	Relatively close together	Relatively wide apart
Precementum layer	Virtually absent	Present

Difference between alveolar bone, cementum, dentin and enamel

	Alveolar bone	Cementum	Dentin	Enamel
Derived from	Mesoderm	Ectomesenchyme	Ectomesenchyme	Ectoderm
Cell of origin	Osteoblast	Cementoblast	Odontoblast	Ameloblast
Cells in mature tissue	Osteocytes	Cemetocytes (absent in acellular cementum)	Odontoblasts	Does not persist
Degrading cells	Osteoclasts	Cementoclasts / odontoclasts	Odontoclast	Odontoclast
Matrix vesicle formation	Observed	Observed	Observed	Not seen
Apatite content (in %)	50 to 60	45 -50	70	96
Primary organic content	Collagen	Collagen	Collagen	Enamel proteins
Remodeling	High rate	No remodeling	No remodeling	No remodeling
Repair	By new bone	By new cementum	By tertiary dentin	No repair except remineralization in surface
Incremental lines	Resting and reversal lines	Slater	Von Ebner, Owen, neonatal line	Retzius, neonatal line
Nerve innervation	Yes	Nil	Yes – only pain fibers	Nil
Vascularity	Yes	No vascular channels	No vascular channels	No vascular channels

Age estimation from mixed dentition cast

Age of the child and teeth present during mixed dentition

Maxillary arch (in each quadrant )	Age of the child	Mandibular arch (in each quadrant)
Intact deciduous dentition	Below 6years	Intact deciduous dentition
Intact deciduous dentition with permanent first molar	About 6 years	Intact deciduous dentition with permanent first molar
6 E D C B 1	6 – 7 yrs	1 C D E 6
6 E D C 1	7 – 8 yrs	1 2 C D E 6
6 E D C 2 1	8 – 9 yrs	1 2 C E 6
6 E C 2 1	9 – 10 yrs	1 2 E 6
6 E 4 C 2 1	10 yrs	1 2 3 4 E 6
6 5 4 2 1	10 – 11 yrs	1 2 3 4 6
6 5 4 3 2 1	11 – 12 yrs	1 2 3 4 5 6
7 6 5 4 3 2 1	12 yrs and above	1 2 3 4 5 6 7