OralHistology

Questions	Answer
Calcitonin -gene-related peptide and substance P in pulp cause	Vasodilation and increased capillary permeability
The approximate number of axons entering the apical foramen is	2500 axons
The percentage of axons in tooth that are myelinated is	25 percentage
The type of nerve fibres in teeth	90% are narrow A delta  and 10% are wider A beta group []
The Plexus of Raschkow is not evident till	The tooth is erupted
The unsheathed axons of dentin are most often restricted to	Coronal dentin
What is predentinal plexus of Bradlaw	Is an area where a number of axons congregate and houses unsheathed axons. Also houses the dentinal dentritic antigen presenting cell
Subodontoblastic zone contains a lot of	Cell processes. It is anuclear and devoid of other structures as per EM studies
In pulp, the level of glycosaminoglycan peaks till	Eruption of teeth
The main ground substance in developing pulp  is the	Chondroitin sulfate. In mature pulp it is hyaluronan

Tooth Morphology

Questions	Answer
Function of biglycan	Help to regulate collagen fbrillogenesis
Function of tenascin	Associated with cell movements
Function of osteoadherin	Associated with mineralization
Glycoproteins in pulp	Collagen, fibronectin and tenascin
Why is odontoblast layer described as pseudostratified	The nuclei of adjacent odontoblast lie at different levels and sectioning plane cause this appearance
Cell junction present in odontoblasts are	Macula adherens, tight junctions and gap junction
The control of blood flow is under	Nervous system
The pulpal arteriolar smooth muscle is innervated by	Sympathetic nerves
The vasoconstrictor tone of pulpal arterioles are mainatined by	Sympathetic nerves and neurotransmitters are noradrnealine and neuropeptide Y
The most prominent neuropeptide in pulpal nerves are	Calcitonin -gene-related peptide and substance P

Oral Histology

Questions	Answer
During odontoblast differentiation, where does fibronectin and decorin accumulate?	Along the distal pole of the differentiating cell
At what place does Dentin phospoprotein bond to collagen?	In a highly specific manner, DPP bonds to the e-band of the gap region of the type I collagen fibril
Role of Dentin Phospoprotein in mineralization	1. Transport of ions in to mineralization front; 2. Aggregation of collagen fibril; 3. Location of nucleation to specific region of collagen fibril; 4. Stabilization and orientation of formed collagen
Presence of matrix vesicle is limited to	mantle dentin is relatively less mineralized; collagen fiber are perpendicular to enamel; branched dentinal tubule; presence of mineralization by matrix mineralization
Chains in Type III collagen	only alpha 1 chains
The only glycosaminoglycans that is found unbound to any protein is	Hyaluronic acid
composition of glycosaminoglycans in mature pulp	60% Hyaluronic acid; 20% dermatan sulphate; 12% chondroitin sulphate and rest heparin sulphate
composition of glycosaminoglycans in developing pulp	Chondroitin sulphate is major amd hyaluronic acid minor component
function of versican	contribute to the bulk of proteoglycans and form large hydrated aggregates creating a gel
function of decorin	binds to type I collagen and helps in mineralization front

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NEXT POST ON MONDAY, the 28th October 2013

Dentin

Questions	Answer
Peritubular in interglobular dentin is a	Absent as interglobular dentin is  uncalcified
The looping of dentinal tubules in radicular dentin causes	Airspaces formation in the loop in ground section, resulting in internal reflection of transmitted light causing Tomes granular layer
Reason for absence of Tomes granular layer in crown is	Differences in rate of formation of dentinal tubule
Lines associated with primary curvature of dentin is	Schreger line - differentiating primary and secondary dentin
Lines associated with secondary curvature of dentin is	Contour line of Owen; neonatal line
short period deposition of incremental lines in dentin are commonly called as	von Ebner's line
The coarser long period lines in dentin are called as	Andresen line
Between two Andresen lines in dentin, there are ___________ number of von Ebner lines	six to 10 pairs
Where is the primary enamel knot found?	It is a found in the tip of epithelial tooth bud and is a signalling center
Where is the secondary enamel knot found?	At the site of future cusp tips

Tooth Morphology

Questions	Answer
The tooth at the centre of a fully developed adult jaw is the	First molar
In a permanent maxillary first molar the buccal developmental groove is parallel to the	Distobuccal root
The root tips of the permanent maxillary first molar often curve towards the	Centre axis
The cusp arm of the mesiopalatal cusp of a typical permanent maxillary first molar is	Obtuse angled. It is the most obtuse angled cusp. Hence it is the bluntest cusp of the entire cusps.
The distobuccal and mesiolingual cusp form has	Right angled
The usually missing cusp in a permanent maxillary second molar, if missing is the	Distopalatal cusp
The shortest teeth occlusocervically in the mandible is the	Second molar
In the permanent dentition the buccal ridges and height of contour forms a “tilited E shaped” pattern in	Mandibular first molar. The lingual ridges and the height of contour forms the “U shaped” pattern.
The lingual developmental groove of the permanent mandibular first molar is aligned with the	Furcation
In a maxillary molar the most indistinct and rounded line angle is the	Distobuccal

Tooth Morphology

Questions	Answer
The teeth with both the contact areas at the same level are the	Mandibular first premolar
Mesial marginal grove is seen in the __________ teeth of permanent dentition.	Maxillary first premolar
Mesiolingual developmental grove is seen in the __________ teeth of permanent dentition.	Mandibular first premolar
In a 3-cusp version of permanent mandibular second premolar, the largest cusp is the	Buccal cusp followed by Mesiolingual cusp and Distolingual cusp
A prominent lingual ridge is a feature of	Maxillary first premolar
Most commonly, the permanent mandibular second premolar arises from	5 lobes. Most commonly, the 3-cusp variant is the commonest one. It has 3 buccal lobes and 2 lingual lobes.
The poorly developed lingual cusp is observed with	Mandibular first premolar
In a permanent dentition, buccal and lingual or palatal cusps are well within the confines of root trunks in the	Maxillary posterior teeth
The permanent mandibular second premolar resembles the first premolar only from the	Buccal aspect
The distolingual cusp ridge of ____________ teeth has a developmental depression on it.	Mandibular second premolar. It is a common feature of the 2 cusp type.