Posterior Palatal Seal

# Excess height of the posterior palatal seal of a complete maxillary denture will usually result in which of the following?
A. Increased retention
B. A tingling or tickling sensation
C. Unseating of the denture
D. Gagging

The correct answer is C. Unseating of the denture.

Over contouring or excessive beading of the posterior palatal seal causes too much pressure to be exerted on the palatal tissues resulting in the unseating of upper dentures. 

The posterior palatal seal is typically placed approximately on the vibrating line between the hard and soft palate and provides a physiologically acceptable tissue pressure within the compressible portion of the soft palate to attain retention and peripheral seal. 

Over extending the coverage of seal will cause gaggling and painful swallowing for the part of the patient. 

Vertical Dimension of Occlusion (VDO)

# A denture that is fabricated with excessive Vertical Dimension of Occlusion (VDO) may result in:
A. Inefficient mastication
B. Perioral rhytides (wrinkles)
C. Trauma to supporting soft tissue
D. Sagging oral commissures

The correct answer is C. Trauma to supporting soft tissue. 

Perioral rhytides, sagging oral commisures and deep labiomental groove is an indication that the vertical dimension of occlusion is insufficient. 

Excessive vertical dimension of occlusion (VDO) causes pain in the soft tissue under the denture because excessive force is created during occlusion. 

Excessive VDO manifests as a "full mouth" as well as a difficulty pronouncing words. 

Most Sensitive to X Ray

# Which of the following are most sensitive to X ray?
A. Tooth buds and salivary glands
B. Nerve and muscle tissue
C. Hair and nails
D. Cartilage

The correct answer is A. Tooth buds and Salivary glands


Non keratinized gingival tissue

# Which of the following is an example of non keratinized gingival tissue?
A. Outer gingival epithelium 
B. Gingival col
C. Marginal gingiva 
D. Attached gingiva

The gingival tissue is made up of 75% Para keratinized epithelium, about 15 % keratinized and only 10% non keratinized epithelium.

The keratinized area of the gingiva includes the attached gingiva and some portions of the outer gingival epithelium. 

The para keratinized gingiva includes the marginal gingiva and portions of the outer gingival epithelium.

The non keratinized portion of gingiva includes the gingival col, junctional epithelium and sulcular epithelium.


First Confirmed Death Due to Corona Virus in Nepal - COVID19

A 29 year old postnatal woman who had delivered a baby on 24th Baisakh 2077, at Institute of Medicine, Teaching Hospital, Maharajgnj and had been discharged on 25th Baisakh 2077 died due to complications arising due to Corona Virus Infection. When she developed symptoms like difficulty in breathing, she was brought to Dhulikhel Hospital for emergency treatment.

This is the first official Case of COVID-19 in Nepal which took a life. The total number of infected people has reached 281. Nepal is on the 54th day of  a nationwide lockdown, since 12th Chaitra 2076.

AIIMS MDS Entrance MCQs - November 2008

# Main component of bacterial plaque:
A. Bacteria and Food Product
B. Bacteria and Bacterial products
C. Food debris and salivary mucins
D. Degenerating epithelial cells and salivary mucins

# Inorganic component of plaque is formed of:
A. Calcium and fluoride
B. Calcium and sodium
C. Calcium and Phosphorous
D. Sodium and Calcium

2nd Year MBBS Unit-5 Internal Assessment, May 2000 Paper - III B (CNS) SHORT ANSWER QUESTIONS

 8th May 2000

2nd Year MBBS Unit-5
Internal Assessment, May 2000
Paper - III B
Time: 2 hours                                                                                       
                    Maximum Marks: 125

Please answer each section in a separate answer book.


1.    Describe the formation of arterial circle at the base of human brain.                       
2.   a.    State the extent and subdivisions of the spinal nucleus of the trigeminal nerve.     2
b.    Which sensory modalities are sub-served by each of these subdivisions.               1.5
c.    Describe the afferent and efferent connections responsible for the corneal reflex. 1.5
3.    a.    Describe how the thalamic nuclei are classified.                                       
b.    What is the ventral posterior nucleus of the thalamus concerned with?                 1
c.    Enumerate four major afferents to this nucleus.                                             
4.   Enumerate the afferent and efferent tracts passing through superior cerebellar  peduncle.     
5.   Enumerate the peripheral parasympathetic ganglia of the head region and
mention the structures supplied by each one of them.                                               
6.   Enumerate the functional components, nuclei, and branches of the
glossopharyngeal nerve.                                                                           
7.    Describe the lateral medullary syndrome of Wallenberg.                                       
8.    Describe the formation and termination of the medial lemniscus of brain.                    5


9.    List three important functions of CSF. Explain the contrecoup phenomena.                3+1

10.  Describe briefly the sites and mechanisms of formation of CSF.                               

11.  Compare the ionic basis of EPSP and IPSP.                                                     

12. State the important functions of primary & secondary somatosensory cortex. 3

13.  Draw a diagram showing descending modulation of pain.                                         

14.  State the functional differences between intrafusal & extrafusal muscle fibers.            3

15. Explain briefly with the help of a diagram the functional divisions of the

16. State mechanisms underlying cortical arousal and explain how the system can
be activated by emotional stress.                                                                 
17. Describe briefly characteristic features of slow wave sleep and name two neurotransmitters
associated with production of sleep.                                                  4
18.  Name two major reward centers and explain briefly their functional implication.        4
19.  Explain the terms: Memory trace and Habituation.                                             


20.  What are “Prion Diseases”? Name four diseases that fall under this category.            3+2

21. Tabulate 2 important differences between brain infarction caused by thrombosis
and embolism.                                                                                     

22.  Classify neuroepithelial tumors of CNS.                                                       


23.  Explain why:                                                                                 
a.    Naloxone is used in acute morphine over dosage.
b.   Diazepam is used as preanaesthetic medication before surgery.
c.    Anticholinergic drugs are used to treat neuroleptics induced extra pyramidal motor side
d.   Phenytoin can cause osteomalacia and megalobalstic anaemia after prolonged use.
e.    Lignocaine with adrenaline is not used for ring block anaesthecia in index finger.

24. Describe briefly the mechanism of action, common side effects and clinical
uses of the following drugs.                                                                       
a.    Carbamazepine
b.   Haloperidol


25.  Describe briefly the types of learning.                                                       
26. Describe briefly the biological basis of memory with reference to LTP
(Long Term Potentiation)                                                                           
27.  Describe briefly the concept of intelligence.                                                 

BPKIHS Internal Assessment, May 2000 - MULTIPLE CHOICE QUESTIONS, CNS Paper IIIB

                                                                     8th May 2000

2nd Year MBBS Unit-5
Internal Assessment, May 2000
Paper - III B

Time: 1 hour                                                                                       
                     Maximum Marks: 75


1.   Which of the following fibers do not enter the cerebellum via inferior cerebellar peduncle?
a.    Anterior spinocerebellar tract
b.   Posterior spinocerebellar tract
c.    Olivocerebellar tract
d.    Reticulocerebellar fibres                                                                   
             Key: (a)

2.   The only one noncortical structure to receive efferents from thalamus is:
a.    Neostriatum
b.   Cerebellum
c.    Spinal cord
d.    Pons                                                                                         
                        Key: (a)

3.   Largest afferent fiber bundle that ends in the hypothalamus is:
a.    Medial forebrain bundle
b.    Fornix
c.    Stria terminalis
d.    Dorsal longitudinal fasciculus                                                               
          Key: (b)

4.   Occlusion of which area of the circle of Willis will result in total unilateral blindness?
a.    Anterior cerebral artery
b.   Ophthalmic artery
c.    Anterior choroidal artery
d.    Posterior communicating artery                                                               
       Key: (b)

5.   The fourth ventricle of the brain communicates superiorly with third ventricle through the:
a.    Cerebral aqueduct
b.   Foramen of Magendi
c.    Foramen of Luschka
d.    Central canal of medulla oblongata                                                           
     Key: (a)

6.   In which region of spinal cord lie the preganglionic neurons of the sympathetic nervous
a.    Cervical
b.    Thoracic
c.    Sacral
d.    Coccygeal                                                                                   
                    Key: (b)

7.   Which of the following structures has unipolar neurons ?
a.    Anterior horn of spinal cord
b.   Sympathetic ganglion
c.    Dorsal root ganglion of spinal nerve
d.    Posterior horn of spinal cord                                                               
           Key: (c)

8.   The habenular nucleus receives the nerve fibers from:
a.    Stria medullaris thalami
b.   Ansa lenticularis
c.    Medial longitudinal fasciculus
d.    Lateral lemniscus                                                                             
                Key: (a)

9.   Linea splendens is a:
a.    Groove in the Insula
b.   Oblique ridge in the thyroid cartilage
c.    Covering of thalamus
d.    Thickened band of pia mater                                                                   
         Key: (d)

10. Brain region primarily involved in aggressive behaviour is:
a.    Hippocampus
b.   Amygdala
c.    Hypothalamus
d.    Thalamus                                                                                      
                    Key: (b)

11. The neural mechanisms involved in motor planning for expression of words are located in:
a.    Wernicke’s area
b.    Brocas area
c.    Visual association cortex
d.    Prefrontal cortex                                                                             
                  Key: (b)

12. Which of the following substances pass through blood brain barrier with greatest ease:
a.    H+ ions
b.   Polypeptides
c.    CO2 and O2
d.    Glucose                                                                                       
                      Key: (c)

13. Desynchronized EEG may be associated with:
a.    Awake relaxed state
b.    REM sleep
c.    Slow wave sleep
d.    Unconscious state                                                                             
                Key: (b)

14. Lesion in the primary motor cortex is most likely to produce all of the following EXCEPT:
a.    Hypotonia
b.   Loss of localized movements
c.    Loss of fine movements
d.    Babinski negative                                                                             
                Key: (d)

15. The sensory pathway passing through non specific thalamic nuclei is mainly responsible for:
a.    Conscious perception of stimuli
b.   Some reflex responses
c.    General arousal
d.    Physical orientation                                                                          
                Key: (c)

16. All of the following facts regarding synaptic transmission are true EXCEPT:
a.    Presynaptic Ca++ influx occurs through voltage gated channels
b.   Postsynaptic reaction of neurotransmitter results in increased Na+ influx
c.    Magnitude of EPSP depends on the amount of neurotransmitter released
d.   Action potential apperaing at presynaptic terminal passes to postsynaptic terminal unmodified.
Key: (d)

17. Representation of different body parts in the somatosensory cortex is proportional to:
a.    Importance of the body part in sensory perception
b.    The size of the body part
c.    Mobility of the body part
d.    Degree of usage of the body part                                                              
       Key: (a)

18. Loss of consciousness produced by general anaesthetic involves:
a.    Reticular activating system
b.   Raphe magnus
c.    Nor-epinephrine
d.    Serotonin                                                                                     
                     Key: (a)

19. A strong electric shock passing through the brain will:
a.    Impair remote memory
b.   Impair recent memory
c.    Impair all memories equally
d.    Not effect memory                                                                             
              Key: (b)

20. Phenylalanine is the precursor of:
a.    Catecholamines
b.   Thyroid hormone
c.    Steroid
d.    Acetyl choline                                                                                
                  Key: (a)

21. All the following events occur during visual cycle EXCEPT:
a.    Activation of transducin
b.   Separation of α - subunit from  -  subunit of G protein
c.    Conversion of cyclic AMP to 5 ‘ AMP
d.    Closure of sodium channel                                                                     
          Key: (c)

22. All the statements regarding the polyol pathway are correct EXCEPT:
a.    the pathway occurs in liver
b.   the pathway deals with the formation of fructose from glucose
c.    both NADPH and NAD are required for the pathway
d.    inhibition of aldose reductase blocks the pathway                            Key: (a)

23. All of the following microscopic features are seen in Alzheimer’s disease EXCEPT:
a.    Neurofibrillary tangles
b.    Pick bodies
c.    Neuritic plaques
d.    Amyloid angiopathy                                                                            
             Key: (b)

24.  Negri bodies are seen in which of the following diseases ?
a.    Alzheimer’s disease
b.    Rabies
c.    Herpes simplex infection
d.    HIV infection                                                                                 
                  Key: (b)

25. All the following are childhood CNS tumors EXCEPT:
a.    Medulloblastoma
b.   Ependymoma
c.    Primitive neuroectodermal tumor
d.    Oligodendroglioma                                                                             
             Key: (d)

26. All the following tumors of CNS arise in posterior fossa of brain EXCEPT:
a.    Medulloblastoma
b.   Ependymoma
c.    Meningioma
d.    Pilocytic astrocytoma                                                                         
              Key: (c)

27. The following test is used for diagnosis of Japanese encephalitis in a patient:
a.    IgG detection in a single serum sample
b.   IgM capture ELISA in a single serum sample
c.    Raised protein level in CSF
d.    Low glucose level in CSF                                                                      
          Key: (b)

28. Which of the following species act as amplifying hosts of Japanese Encephalitis (JE) virus:
a.    Water birds and man
b.    Pigs and man
c.    Water birds and pigs
d.    Cows and goats                                                                                
                Key: (c)

29. In acute bacterial meningitis important CSF findings are:
a.    Lmphocytic pleocytosis and reduced protein content
b.   Predominantly polymorphonuclear cells and reduced glucose content
c.    Mixed cellular reaction with normal protein and glucose levels
d.    Clear CSF with occasional macrophages                                          Key: (b)

30. Which one of the following drugs is used for prophylaxis of manic depressive illness ?
a.    Lithium
b.   Chlorpromazine
c.    Imipramine
d.    Fluoxetine                                                                                    
                     Key: (a)

31. Which of the following drugs is used in the treatment of chronic addiction to morphine:
a.    Naloxone
b.   Diazepam
c.    Methadone
d.    Phenobarbitone                                                                                
                Key: (c)

32. Which one of the following drugs is often combined with a potent narcotic analgesic such as 
fentanyl to produce neuroleptanalgesia ?
a.    Haloperidol
b.   Droperidol
c.    Chlorpromazine
d.    Trifluoperazine                                                                               
                  Key: (b)

Forensic Medicine
33. Brain stem death has been legally accepted in Nepal since: 
a.    2050
b.    2052
c.    2055
d.    2057                                                                                          
                        Key: (c)

34. Which one of the following functions is true for ability to compare between an airplane and a 
a.  Abstraction
b.  Intelligence
c.  Judgement
d.  Memory                                                                                          
                   Key: (a)

35. All of the following are true for cognition EXCEPT:
a.  Memory
b.  Complex use of symbols
c.  Planning
d.  Special sensations                                                                              
                Key: (d)

36.  A child goes to toilet instead of soiling the clothes to avoid a 'time out'. This is an 
example of learning:
a.  Operant conditioning
b.  Pavlovian (classical) conditioning
c.  Social learning
d.  None of the above                                                                               
               Key: (a)

37. Amnesia due to hysteria occurs because of :
a.  Loss of neurons
b.  Loss of neurotransmitters
c.  Repression of unacceptable feelings or thoughts
d.  Conscious avoidance of the event                                                                
     Key: (c)

Section 'B'
38. Archicerebellum is made up of:
1.    Pyramid
2.    Lingula
3.    Uvula
4.    Flocculonodular lobe                                                                          
             Key: (c)

39. Inhibitory neurotransmitters are:
1.    GABA
2.   Acetylcholine
3.   Dopamine
4.    Serotonin                                                                                     
                     Key: B

40. Therapeutic drug monitoring is essential for which of the following drugs:
1.    Diazepam
2.   Lithium carbonate
3.   Chlorpromazine
4.    Phenytoin                                                                                     
                     Key: (c)

41. Which of the following statements about nitrous oxide (N2 O) are true:
1.    It is a non-inflammable gas
2.   Potent anaesthetic
3.   Good analgesic
4.    Good muscle relaxant                                                                          
             Key: (b)

Forensic Medicine
42.  In brain stem death:
1.    Spontaneous respiration continues
2.   Spontaneous cardiac action continues
3.   Gag reflex is present
4.    EEG is flat and isoelectric                                                                   
             Key: (C)


43. A:  Neurotransmitter has shorter duration of action than neuromodulator.
R:   Neuromodulater has longer latent period.                                                       
        Key: (A)

44. A:  Serological detection of Gr B meningococcal meningitis is difficult.
R:   The polysaccharide capsule of Gr B meningococci is a poor immunogen.            
Key: (A)

45. A:  Benzodiazepines are preferred over barbiturates as sedative hypnotics.
R:   Benzodiazepines act through Benzodiazepines receptor and are facilitatory to GABA.
Key: (b)


46. A 50 year old male who came with a complaint of muscular rigidity, slow tremor, mask-like face, 
and shuffling gait was diagnosed as a case of Parkinson’s disease.

Parkinson’s disease is caused by destruction of which part of the brain:
a.    Motor cortex
b.   Dentate nucleus
c.    Reticular formation
d.    Substantia nigra                                                                              
                  Key (d)

47. A 40 year old man visited his physician because of muscular hypotonia, scanning speech and 

Dysdiadochokinesia is defined as:
a.    Rhythmical oscillation of eyes
b.   Inability to perform alternating movements regularly and rapidly
c.    Loss of resilience of muscles to palpation
d.    Movement produced by tendon reflexes are prolonged                                   Key: (b)

48. A patient consulted a doctor with a complaint of double vision, which he developed after 
sustaining a head injury in an accident. On examination, the doctor found that the patient had 
squint and was unable to move his right eye laterally.

Which nerve is likely to be involved ?
a.    Oculomotor
b.   Trochlear
c.    Abducent
d.    Nasociliary                                                                                   
                    Key: (c)

49. A patient who had loss of taste sensation on posterior one third of the tongue, paralysis of 
one half of the tongue, and difficulty in swallowing was diagnosed as a case of brain tumor.

The most likely site for the presence of the tumor would be:
a.    Internal capsule
b.   Cerebellum
c.    Mid brain
d.    Medulla oblongata                                                                             
               Key: (d)
50. A 25 year old motorcyclist was brought to the emergency with an accident involving severe 
injury at the sacral level. On examination, his legs were found to be dangling passively & were not 
responding to neurological examination.

Injury to the spinal cord in this case might have resulted in:
a.    Upper motor neuron lesion
b.   Paresis of leg muscles
c.    Spastic paralysis of the legs
d.    Flaccid paralysis of the legs                                                                 
            Key: (d)
51. A patient with cerebellar lesion demonstrates a characteristic gait of a drunkard. The 
in-coordinated movements in such patients may be due to all of the following EXCEPT:
a.    Abnormal stretch reflex path
b.   Imperfect choice of motor units
c.    Improper duration of contraction
d.    In-coordination of agonists and antagonist                                                    
  Key: (a)

52. A patient was brought to the emergency with spinal cord injury at T1 after having run over by a 
motorcycle. He was in a state of shock. During clinical examination of reflexes, which of the 
following reflexes is likely to be elicited:
a.    Jaw Jerk
b.   Pupillary reflex

c.    Knee Jerk
d.    Babinski reflex                                                                               
                  Key: (b)

53. A patient attended medical OPD with a complaint of loss of appetite, palpitation and insomnia 
for the last one week. History revealed that he was earlier treated for addiction to alcohol.

Brain region primarily involved in his case would be:
a.    Brain stem reticular formation
b.   Amygdaloid nuclei
c.    Hypothalamus
d.    Sensory cortex                                                                                
                  Key: (c)

54.  A 10 year old child came to BPKIHS emergency with history of unconsciousness and high grade 
fever. A lumber puncture for C.S.F. analysis was done and the CSF glucose was found to be 
remarkably lower than normal.

The most likely cause for the lowered CSF glucose may be due to:
a.    Meningioma
b.   Infarction
c.    Multiple sclerosis
d.    Meningitis                                                                                    
                    Key: (d)

55. A 5 year old female patient presented to the emergency with history of fever since 4 days 
accompanied by vomiting, neck rigidity and altered consciousness. Differential count of the CSF 
showed 90% polymorphonuclear cells.

The patient most probably was suffering from:
a.    Brain abscess
b.   Subarachnoid haemorhage
c.    Acute bacterial meningitis
d.    Tuberculous meningitis                                                                        
            Key: (c)

56. A 30 year old male consumed two mollusc from a water source on the advice of a local faith 
healer. About 10 days after ingestion, he was admitted to the hospital with severe headache, 
retention of urine and paralysis of lower limbs. Characteristically, there was no fever, CSF showed 
pleocytosis with 75% of cells being eosinophils.  mollusc obtained from the same water source were 
inoculated into rats. Brain tissue of the rats showed acute inflammation and adult helminthic worms 
were recovered from animals.

The most likely aetiological agent of this condition could be:
a.    Trichenella spiralis
b.   Schistosoma haematobium
c.    Angiostrongylus cantonensis
d.    Echinococcus granulosus                                                                       
          Key: (c)

57. A 52 year old, female patient, who had an untreatable hepatic carcinoma was to undergo foot 

Which  of  the  following  local  anaesthetic  agents  is  safe  in  this  patient  based  on  her  
history  of carcinoma:
a.    Lidocaine
b.   Prilocaine
c.    Mepivacaine
d.    Procaine                                                                                      
                      Key: (d)

58. A 45 year old man who was injured in a car accident was brought to the emergency room. His 
blood alcohol level on admission was 275mg/dl. His wife confirm that he was drinking heavily for 
the past 3 weeks.

Which of the following drugs would offer relief to the patient during withdrawal of alcohol?
a.    Phenytoin
b.   Diazepam
c.    Disulfiram
d.    Phenobarbitone                                                                                
                Key: (b)

59. A 65 year old male patient suffering from endogenous depression developed urinary retention 
after taking amitriptyline from a private practitioner.

Which of the following antidepressant drugs would be best suited for him?
a.    Imipramine
b.   Nortriptyline
c.    Fluoxetine
d.    Amoxapine                                                                                     
                  Key: (c)

60. A 20 year old college student complained that for the last couple of weeks his friends were 
gossiping among themselves against him, teasing him on the road , spreading his illness through TV 
& news agencies. He attacked some of the friends and was brought to hospital. His family didn't 
share his views.

The phenomenon described of above is a type of :
a.    Hallucination
b.    Delusion
c.    Misinterpretation
d.    abnormal emotional responses                                                                  
       Key: (b)

Most Important Operative Dentistry MCQs With Explanations

1. The following chemically bond to the tooth:
A. Composite resin.
B. Dental sealants.
C. Glass ionomer cement. ***
D. All of the above.

2. Compomer restorative materials are:
A. Glass ionomer with polymer components
B. Resin systems with fluoride containing glasses. ***
C. Composite resin for cervical restorations only.

Explanation: The composition of compomers is similar to that of a dental composite however it has been modified, making it a polyacid-modified composite. This results in compomers still requiring a bonding system to bond to tooth tissue.

Although the name compomer implies that the material possesses a combination of characteristics of both composite and glass ionomers, these materials are essentially polymer-based composites that have been slightly modified to take advantages of the potential fluoride-releasing behavior of glass ionomers.

3. Loose enamel rods at the gingival floor of a class II amalgam cavity should be removed using :
A. Straight chisel.
B. Hatchet.
C. Gingival curette
D. Gingival marginal trimmer. ***

Explanation: Gingival marginal trimmers are primarily used for beveling gingival margins, and rounding or beveling of the axiopulpal line angle of Class II preparations. The gingival margin trimmer is designed to produce a proper bevel on gingival enamel margins of proximoocclusal preparations.

4. Removal of Undermined Enamel in Class II cavity is done by :
A. Chisel. ***
B. Angle former
C. Excavator

Explanation: PROXIMAL (CLASS II):
A chisel can be used to plane away unsupported enamel from the
margins of the completed preparation to produce a 90° butt joint.

5. What is the cavo-surface angle of prep for amalgam restoration:
A. 30 degree
B. 60 degree
C. 90 degree ***
D. 130 degree.

6. Hand instrument which we used to make internal angles retentive grooves and preparation of cavity walls in the cavity is:
E. Angle former. ***
F. Chisel.
G. File.
H. Enamel hatchet

7. To provide maximum strength of amalgam restoration the cavo-surface angles
1. Approach 75 with outer surface.
2. Approach 90 with outer surface.
3. Be supported by sound dentine.
4. Be located in area free of occlusal stress.
A. 1+3 and 4.
B. 1+3.
C. 2+3+4. ***
D. 3+4.

8. Which of the following materials has been shown to stimulate reparative dentine
formation most effectively when applied to the pulpal wall of a very deep cavity:
A. Copalite varnish.
B. Calcium hydroxide preparation. ***
C. Zinc phosphate cement.
D. Anhydrous glass ionomer cement.

9. Calcium hydroxide is the best pulp capping material because:
A. It has the best seal over pulp.
B. It is alkaline + less irritating to the pulp.
C. It induces reparation dentine formation. ***

10. Clinical failure of the amalgam restoration usually occurs from:
A. Improper cavity preparation. ***
B. Faulty manipulation.
C. Both of the above.
D. None of the above.

11. It has been proven that amalgam restoration has the following characteristics:
1. Micro leakage decrease with the aging of the amalgam restoration.
2. It is the least technique sensitive of all current direct restorations.
3. High dimensional changes.
A. 1 , 2 and 3.
B. 1 and 3.
C. 1 and 2. ***
D. 2 only.

** During electrochemical corrosion of low-copper amalgams, The Sn-Hg phase is oxidized into Sn-O and/or Sn-O-Cl. The oxychloride species is soluble.
** The oxide Precipitates as crystals and tends to fill up the spaces Occupied by the original Sn-Hg phase. Along the margins Of the amalgam, Sn-O helps seal the space against Microleakage.
** During setting, most amalgams undergo very little Dimensional change.
** The dimensional change during the setting of amalgam is one of its most characteristic properties.
** Modern amalgams mixed with mechanical amalgamators usually have negative dimensional changes.
**The only exception to this statement is the excessive delayed dimensional change resulting from
contamination of a zinc-containing alloy with water during trituration or condensation.

12. When polishing the amalgam restoration:
A. Avoid heat generation by using wet polishing paste.
B. Wait 24 hours.
C. A and b. ***
D. B only.

13. Maximum time elapsed before condensation of amalgam after titration:
A. 1minute.
B. 3minutes. ***
C. 9minutes.

14. After amalgam trituration, the mix should be placed within:
A. 1 min. ***
B. 3 min. ***
C. 5 min.

15. MOD amalgam restoration with deep mesial box, patient comes with pain related to it after 1 month due to:
A. Pulp involvement. ***
B. Supraocclusion.
C. Upon contact.
D. Gingival recession.

16. Reduction in amalgam restoration should be:
A. 1-1.5 mm.
B. 1.5-2 mm. ***
C. 2-3 mm.
D. 3-5 mm.

Explanation: ** It must have a minimum thickness of 0.75 to 2 mm. (because of its lack of compressive strength)

17. Depth of amalgam restoration should be:
A. 1 – 1.5 mm.
B. 1.5 – 2 mm. ***
C. 2 – 3 mm.
D. 3 – 5 mm.

18. Silicate cement:
1. First tooth colored restoration.
2. It can be used as permanent filling.
3. It contains 15 % fluoride.
A. 1 , 2 and 3.
B. 1 and 2.
C. 1 and 3. ***
D. 1 only.

Silicate cement , the first translucent filling material, was introduced in 1878 by Fletcher in England . Silicate cement contain 12-25 % Fluoride. ZOE , reinforced ZOE, ZOE-EBA, Silicate and zinc phosphate cements are no longer routinely used to permanently cement restorations.

19. Length of pins must be equals in both tooth and restoration by a depth of:
A. 1 mm.
B. 2 mm. ***
C. 3 mm.
D. 4 mm.

20. Stainless steel pin is used in amalgam for:
A. Increased retention. ***
B. Increased resistance.
C. Increased strength.
D. A and b.

21. What can we use under composite restoration:
A. Ca (oh). ***
C. ZINC phosphate cement.

22. The x- ray of choice to detect the proximal caries of the anterior teeth is:
A. Periapical x-ray. ***
B. Bitewing x-ray.
C. Occlusal x-ray.
D. None of the above.

23. What is the copper ratio that eliminates gamma phase 2:
A. 2% copper
B. 4% copper
C. 10 % copper
D. 13 % copper ***

24. To prevent discoloration under amalgam filling:
A. Use Zn phosphate box.
B. Use cavity varnish. ***
C. Wash the cavity with NaOCL b4 filling.
D. Use the correct amalgam-alloy ratio.

25. Polishing bur have:
A. Less than 6 blades.
B. 6-7 blades.
C. 10-12 blades.
D. More than 12 blades. ***

26. Rubber dam is contraindicated in:
A. Pt with obstructive nose. ***
B. Mentally retarded Pt.
C. Un comparative child.
D. A and b.

27. Pt complain from pain in 45 which had gold onlays. The pain could be due to:
A. Chemicals from cement.
B. High thermal conductivity of gold. ***
C. Related to periodontal ligament.
D. Cracked tooth or fractured surface.

Explanation: Disadvantages of gold restoration:
Esthetics – cost – time consuming – difficulty of technique – the need to use cement. (the weakest point in the cast gold restoration) – Gold has high thermal conductivity.

28. Pt complain from pain during mastication which had gold onlays. The pain could be
due to:
A. Chemicals from cement.
B. High thermal conductivity of gold.
C. Related to periodontal ligament. ***
D. Cracked tooth or fractured surface.

29. Class II composite resin is lined by:
A. G.I. ***
B. Reinforced ZOE.
C. ZOE with epoxy cement.
D. Cavity varnish.

30. In cavity preparation, the width of the cavity is:
A. 1/2 inter cuspal distance.
B. 1/3 inter cuspal distance. ***
C. 2/3 inter cuspal distance.

31. Selection of shade for composite is done:
A. Under light.
B. After drying tooth and isolation with rubber dam.
C. None of the above. ***

32. Most commonly, after placement of amalgam restoration PT. Complain from pain with:
A. Hot.
B. Cold. ***
C. Occlusal pressure.
D. Galvanic shock.
E. Sweet.

33. Calcium hydroxide is used in deep cavity because it is:
A. Simulate formation of 2nd dentine. ***
B. Not irritant to the pulp.
C. For thermal isolation.

34. In placement of rubber dam:
A. 4 jaw contact in teeth.
B. Only 4 contacts 2 lingual surface and 2 buccal surface. ***
C. Only 4 contacts 2 mesial and 2 distal.

Contents of Carotid Sheath

# Carotid sheath contains all except:
a) External carotid artery
b) Vagus nerve
c) Internal jugular vein
d) Internal carotid artery

The correct answer is A. External carotid artery

Anatomy of Mandible

# Which of the following structure is not present on the internal surface of mandible?
a) Lingula
b) Genial tubercle
c) Mylohyoid ridge
d) Mental foramen 

The correct answer is D. Mental foramen.


Contents of Brainstem

# Which is not a part of brainstem?
a) Midbrain
b) Cerebellum
c) Medulla oblongata
d) Pons 

The correct answer is B. Cerebellum.

Hardness of Dental Materials

–– Hardness is defined as the ability of a material to resist scratching.
–– Can be divided into microhardness and macrohardness.

Tests for Microhardness:
- Knoop Hardness Test
- Vickers Hardness Test

Tests for Macrohardness:
- Brinell hardness
- Rockwell hardness

1. Brinell Hardness Test

  • Oldest test employed for determining the hardness of metals
  • A hardened steel ball is pressed under a specified load into the polished surface of a material. The load is divided by the area of the projected surface of the indentation, and the quotient is referred to as the Brinell hardness number, usually abbreviated as BHN.
  • For a given load, the smaller the indentation, the larger is the number and the harder is the material.
  • Used extensively for determining the hardness of metals and metallic materials used in dentistry
  • It is related to the proportional limit and ultimate tensile strength of dental gold alloys.

2. Rockwell Hardness Number 

  • Is somewhat similar to Brinell test in that a steel ball or a conical diamond point is used
  • Instead of measuring the diameter of the impression, the depth of penetration is measured directly by a dial gauge on the instrument
  • Neither the Brinell test for the Rockwell test is suitable for brittle materials.
3. Vickers Hardness Test

  • Employs the same principle of hardness testing as Brinell test
  • Instead of a steel ball, a diamond in the shape of a square based pyramidal is used
  • The lengths of the diagonals of the indentation are measured and averaged
  • The Vickers test is employed in the ADA specifications for dental casting gold alloys
  • Suitable for determining the hardness of brittle materials
  • Used for measuring the hardness of tooth structure
4. Knoop Hardness Test
  • Employs a diamond indenting tool that is cut in the geometric configuration
  • The impression is rhombic in outline, and the length of the largest diagonal is measured
  • The hardness value is virtually independent of the ductility of the material tested.
5. Shore and Barcol Test
  • Are employed for measuring the hardness of dental materials, particularly rubbers and plastics

MCQs on Radiation Biology and Safety - Part 1

# Among the natural radiation, the one that contributes to more radiation exposure of general population:
A. Cosmic
B. Terrestrial
C. Radon
D. Consumer products

# X rays cause radiation damage primarily by their property of:
A. Penetration
B. Radioactivity
C. Electromagnetic induction
D. Ionisation

Most radiosensitive cells:

# The most radiosensitive cells in the body are:
A. Endothelial cells
B. Epithelial cells
C. Red blood cells
D. White blood cells

The correct answer is D. White blood cells.

Identical twins develop from:

# Identical twins are produced by fertilization of:
A. 1 ovum by 1 sperm
B. 2 ova by 1 sperm
C. 1 ovum by 2 sperms
D. 2 ova by 2 sperms

The correct answer is: A. 1 ovum by 1 sperm

Twins can be either monozygotic ('identical'), meaning that they develop from one zygote, which splits and forms two embryos, or dizygotic ('non-identical' or 'fraternal'), meaning that each twin develops from a separate egg and each egg is fertilized by its own sperm cell.

Children oral cavity wounds causes

# The leading cause of childhood gingivostomatitis in children aged 1 to 3 is:
A. Herpes Simplex
B. Chicken pox
C. Influenza
D. Rubella

The correct answer is A. Herpes simplex

The primary infection (primary herpetic gingivostomatitis) usually occurs in a chlld under ten years of age who has had no contact with the Type I herpes simplex virus and who therefore has no neutralizing antibodies. It may also affect young adults (15-25). Nearly all primary infections are of the subclinical type (they may only have flu- like symptoms) and one or two mild sores in the mouth which go unnoticed by the parents.

In other children, the primary infection may be manifested by acute symptoms (acute herpetic gingivostomatitis). These include fever; irritability; cervical lymphadenopathy; fiery red gingival tissues; and small, yellowish vesicles that rupture and result in painful ulcers on the free and attached mucosa. The most serious potential problem in a child with this infection is dehydration due to the child not wanting to eat or drink because of the pain.

Treatment is supportive and aimed toward the relief of the acute symptoms so that fluid and nutritional intake can be maintained. Primary herpetic gingivostomatitis usually runs a course of 14-20 days and the ulcers heal without scarring.

Remember: Of all of the herpes viruses, herpes simplex viruses 1 and 2 cause manifestations of recurrent infection in otherwise healthy people.