In performing mandibular nerve block for a child, the most probable cause of failure of anesthesia is:

# In performing mandibular nerve block for a child, the most probable cause of failure of anesthesia is:

A. More concentration of LA is required

B. Because of different angulation of needle

C. Because of position of mandibular foramen

D. None of the above

The correct answer is C. Because of position of mandibular foramen.

Olsen reported that the mandibular foramen is situated at a level lower than the occlusal plane of the primary teeth of the pediatric patient. Therefore the injection must be made slightly lower and more posteriorly than for an adult patient.

Reference: McDONALD AND AVERY’S DENTISTRY FOR THE CHILD AND

ADOLESCENT, TENTH EDITION, Page no 275

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Indirect pulp capping procedures on primary molars are indicated when:

 # Indirect pulp capping procedures on primary molars are indicated when:

A. Removal of decay has exposed the pulp

B. A tooth has a large, long-standing lesion with a history of continuous pain

C. The carious lesion has just penetrated to DEJ

D. The carious lesion is suspected of producing exposure of the pulp

The correct answer is C. The carious lesion has just penetrated to DEJ. 

Indirect Pulp Treatment (IPT)

• Indications: tooth with deep carious lesion, vital pulp

• Objectives: preservation of vitality, arrest of caries advance, formation of tertiary dentin.

• Technique: excavation of most affected dentin, application of medicament over thin layer of sound or carious dentin with no clinically evident pulpal exposure, place Ca(OH)2 or glass ionomer cement, restoration should seal completely, e.g. stainless steel crown

• re-entry for completion of caries removal is not necessary.

Reference: AAPD Handbook of Pediatric Dentistry, Third Edition. Page no 79

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The most caries susceptible teeth in permanent dentition are:

 # The most caries susceptible teeth in permanent dentition are:

A. Lower anterior

B. Second bicuspids

C. First molars

D. Second molars

The correct answer is C. First molars.

Based on the data analyses of the present study, it is concluded that first permanent molars had greatest caries prevalence followed by second permanent molars. Statistically significant associations were found between caries in first permanent molars and caries in other permanent teeth particularly central incisors, premolars, and second molars. Dental caries develops soon after the eruption of permanent first molars and can transmit to other permanent teeth; therefore, school-based oral health promotion programs should address younger children so that high prevalence of caries can be controlled in adolescents with early prevention. Oral health education should be raised in the community through oral health campaigns. Adequate access to public preventive and restorative dental programs and services should be ensured for all the children.

Reference:  First Permanent Molar Caries and its Association with Carious Lesions in Other Permanent Teeth, Muhammad Ashraf Nazir1 , Eman Bakhurji2 , Balgis Osman Gaffar3 , Asim Al-Ansari4 , Khalifa Sulaiman Al-Khalifa5

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Natal teeth are seen:

 # Natal teeth are seen:

A. Within first 30 days of birth

B. Erupt at three months of age

C. At the time of birth

D. At 6 months of age

The correct answer is C. At the time of birth.

The prevalence of natal teeth (teeth present at birth) and neonatal teeth (teeth that erupt during the first 30 days) is low. Leung conducted a retrospective study of hospital records of 50,892 infants born in Calgary, Alberta (Canada). 27 These records identified 15 infants found to have natal teeth, a prevalence of 1 in 3392 births. In another survey Kates and colleagues found the calculated prevalence of natal teeth to be 1 in 3667 among 11,000 infants when the survey information was obtained indirectly; however, in a group of 7155 infants actually examined, the prevalence was found to be 1 in 716.28.

Reference: McDONALD AND AVERY’S DENTISTRY FOR THE CHILD AND ADOLESCENT, TENTH EDITION  Page: 355

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Delayed eruption of at least part of the dentition is a recognized feature of all of the following EXCEPT:

 # Delayed eruption of at least part of the dentition is  a recognized feature of all of the following EXCEPT:

A. Rickets

B. Congenital hyperthyroidism

C. Cleidocranial dysplasia

D. Cherubism

The correct answer is B. Congenital hyperthyroidism.

DELAYED ERUPTION is seen in conditions like:

# Systemic conditons

• Rickets

• Down syndrome

• Hypopituitarism

• Cleidocranial dysplasia

• Achondroplasia

• Cretinism (Congenital Hypothyroidism)

• Fibromatosis gingiva

• Cherubism

# Local conditions

• Fibromatosis gingivae

• Premature exfoliation of primary teeth

• Thickened gingiva

In hyperthyroidism, premature shedding of deciduous teeth and accelerated eruption of permanent teeth is seen.

Reference: Dental Pulse, 9th Edition Volume2 Page No. 604

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Active search for disease in an apparently healthy individual is called:

 # Active search for disease in an apparently healthy individual is called:

A. Monitoring

B. Screening

C. Sentinel surveillance

D. Case finding

The correct answer is B. Screening.

The active search for disease among apparently healthy people is a fundamental aspect of prevention. This is embodied in screening, which has been defined as "the search for unrecognized disease or defect by means of rapidly applied tests, examinations or other procedures in apparently healthy individuals."

Reference: Park's Textbook of Preventive and Social Medicine, 23rd Edition, Page NO. 135

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The most common cell found in healthy periodontal ligament is:

 # The most common cell found in healthy periodontal ligament is:

A. Neutrophil

B. Fibroblast

C. Epithelial cell

D. Osteoblast

The correct answer is B. Fibroblast.

Connective tissue cells include fibroblasts, cementoblasts, and osteoblasts. Fibroblasts are the most common cells in the periodontal ligament; they appear as ovoid or elongated cells oriented along the principal fibers, and they exhibit pseudopodia-like processes. These cells synthesize collagen and possess the capacity to phagocytose “old” collagen fibers and degrade them via enzyme hydrolysis.

Thus, collagen turnover appears to be regulated by fibroblasts in a process of intracellular degradation of collagen that does not involve the action of collagenase.

Reference: Carranza's Clinical Periodontology, 12th Edition, Page no: 25

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