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Crowns of all the permanent teeth, with the exception of the third molars, are calcified by the age of:

 # The crowns of all the permanent teeth, with the exception of the third molars, are calcified by the age of:
A. 6 years
B. 8 years
C. 10 years
D. 12 years


The correct answer is B. 8 years.

Reference: First AID for NBDE Part 1, 3rd edition 2012, Page 660




Most effective method of preventing dental decay

 # Which of the following is the most effective method of preventing dental decay in general population?
A. Oral prophylaxis
B. Systemic fluorides
C. Diet counseling
D. Fluoride mouth wash and toothpaste


The correct answer is D. Fluoride mouthwash and toothpaste.

 The most effective strategy for prevention of caries has been increasing tooth resistance through the use of systemic and topical fluorides. Systemic and topical fluoride application has been deemed by many researchers to be the single most important preventive and treatment modality older adults can employ to prevent dental caries. The concentration and the method and frequency of application
depend on the level of risk and the ability of the individual to manage the regimen.

Reference: Jong's Community Dental Health, 5th edition , Page no 144

Space lattice refers to:

 # Space lattice refers to:
A. Inter atomic movement
B. Inter atomic imbalance
C. Arrangement of atoms
D. Arrangement of molecules



The correct answer is C. Arrangement of atoms.

A space lattice can be defined as any arrangement of atoms in space in which every atom is situated similarly to every other atom.

Reference: PHILLIPS’ SCIENCE OF DENTAL MATERIALS, Anusavice, Shen, Rawls, 12th Edition, Page No: 20


Which of the following bonds is responsible for thermal conduction?

 # Which of the following bonds is responsible for thermal conduction?
A. Ionic bond
B. Van der Waal bond
C. Metallic bond
D. Covalent bond


The correct answer is C. Metallic bond.

The free electrons give the metal its characteristically high thermal and electrical conductivity. These electrons absorb light energy, so that all metals are opaque to transmitted light. The metallic bonds are also responsible for the ability of metals to deform plastically. The free electrons can move through the lattice, whereas their plastic deformability is associated with slip along crystal planes. During slip deformation, electrons easily regroup to retain the cohesive nature of the metal.

Reference: PHILLIPS’ SCIENCE OF DENTAL MATERIALS, Anusavice, Shen, Rawls, 12th Edition, Page No: 19


Atomic bonds characterized by physical forces

 # Which of the following atomic bonds are characterized by physical forces?
A. Ionic bonds
B. Van der Waal bonds
C. Metallic bonds
D. Covalent bonds





The correct answer is B. van der Waals bonds

van der Waals forces—Short-range force of physical attraction that promotes adhesion between
molecules of liquids or molecular crystals.

Reference: PHILLIPS’ SCIENCE OF DENTAL MATERIALS, Anusavice, Shen, Rawls, 12th Edition, Page No: 17


AIIMS MDS ENTRANCE EXAM MCQs - 2012 MAY

 



# Component from second branchial arch is:
A. Mandible
B. Muscles of mastication
C. Muscles of facial expression
D. TMJ

# Sensory nerve supply of TMJ is:
A. Masseteric nerve
B. Auriculotemporal nerve
C. Buccal nerve
D. Facial nerve

# Which blood vessel does not supply pharyngotympanic tube?
A. Ascending pharyngeal
B. Ascending palatine
C. Middle meningeal
D. Artery of pterygoid canal

Crown Height Space (CHS) for implant dentistry is measured from:

# Crown Height Space (CHS) for implant dentistry is measured from:
a) prosthetic platform
b) crest of the bone
c) junctional epithelium
d) gingival margin





The correct answer is B. Crest of the bone.

Crown Height Space(CHS) is measured from crest of bone to the plane of occlusion in posterior region and incisal edge of arch in anterior region.

Gingivitis in leukemic patient resembles:

 # Gingivitis in leukemic patient resembles:
A. Pyogenic granuloma
B. Herpetic gingivostomatitis
C. Hairy cell Leukoplakia
D. ANUG




The correct answer is D. ANUG.

Acute gingivitis and lesions that resemble necrotizing ulcerative gingivitis are more frequent and severe in patients with terminal cases of acute leukemia. The inflamed gingiva in patients with leukemia differs clinically from that found in nonleukemic individuals. The gingiva is a peculiar bluish red, it is spongelike and friable, and it bleeds persistently on the slightest provocation or even spontaneously in leukemic patients. This greatly altered and degenerated tissue is extremely susceptible to bacterial infection, which can be so severe as to cause acute gingival necrosis with pseudomembrane formation or bone exposure.

Reference: Carranza's Clinical Periodontology, 12th Edition, Page no: 194

PUFA index in Dentistry

PUFA (pulp, ulceration, fistula, abscess) provides a measure of badly diseased and broken down teeth which have been attacked by dental decay and are causing significant problems in need of early attention. It is now advocated for use by the FDI as a tool that can help to stress the importance of tackling dental caries to planners (Benzian et  al., 2011b).  It is  interesting  to  note  that in  the  UK,  where there have been massive improvements in oral health, some 7% of dentate adults (adults with teeth) had one or more conditions. A PUFA score of one or more was more common in men than women, adults from lower social groups than more affluent, amongst adults who reported brushing less than once a day than amongst those who brushed once or twice, and amongst smokers rather than non‐smokers.


PUFA index criteria

P  –  pulp involvement is recorded when the opening of the pulp chamber is visible or when the coronal tooth structures have been destroyed by the carious process and only roots/root fragments are left

 U  –  ulceration due to trauma is recorded when sharp edges of a dislocated tooth with pulp involvement or root fragments have caused traumatic ulceration of the surrounding soft tissues, e.g. tongue or buccal mucosa 

F  –  fistula is scored when a pus‐releasing sinus tract related to a tooth with pulp involvement is present

 A  –  abscess is scored when a pus‐containing swelling related to a tooth with pulp involvement is present .

Source:  Monse  et  al., 2011;  Health  and Social  Care  Information Centre, 2011c.

The principal component of dental plaque is:

 # The principal component of dental plaque is:
A. Dextrans
B. Lactic acid
C. Materia alba
D. Microorganism



The correct answer is D. Microorganism.

Dental plaque is composed primarily of microorganisms. One gram of plaque (wet weight) contains approximately 100000000000 bacteria. The number of bacteria in supragingival plaque on a single tooth surface can exceed 1000000000 cells. In a periodontal pocket, counts can range from 1000 bacteria in a healthy crevice to more than 100000000 bacteria in a deep pocket. With the use of highly sensitive molecular techniques for microbial identification, it has been estimated that more than 500 distinct microbial phylotypes can be present as natural inhabitants of dental plaque.

Reference: Carranza's Clinical Periodontology, 12th Edition, Page no:  141


Scaling and root planing:

# Scaling and root planing:
 A. Prevent further loss of attachment in deep pockets
B. Most effective in reducing pocket depth than surgical means
C. More successful in posterior than anterior tooth
D. Same as curettage

 

The correct answer is A. Prevent further loss of attachment in deep pockets.

Of all clinical dental procedures, subgingival scaling and root planing in deep pockets are the most difficult and exacting skills to master. It has been argued that such proficiency in instrumentation cannot be attained, and therefore periodontal surgery is necessary to gain access to root surfaces. Others have argued that although proficiency is possible, it need not be developed because access to the roots can be gained more easily with surgery. However, without mastering subgingival scaling and root-planing skills, the clinician will be severely hampered and unable to treat adequately those patients for whom surgery is contraindicated.

Scaling and root planing alone are effective for reducing pocket depths, gaining increases in periodontal attachment levels, and decreasing inflammation levels (i.e., bleeding with probing). When scaling and root planing are combined with the subgingival placement of sustained-release vehicles, however, additional clinical benefits are possible, including the further reduction of pocket depths, additional gains in clinical attachment levels (e.g., 0.39 mm with minocycline gel), and further decreases in inflammation. Improvements in clinical attachment levels also occur with the chlorhexidine chip (0.16 mm) and doxycycline gel (0.34 mm). When systemic antibiotics are used as adjuncts to scaling and root
planing, the evidence indicates that some systemic antibiotics (e.g., metronidazole, tetracycline) provide additional improvements in attachment levels (0.35 mm for metronidazole; 0.40 mm for tetracycline)
when used as adjuncts to scaling and root planing. The use of anti-infective chemotherapeutic treatment adjuncts does not result in significant patient-centered adverse effects.

Reference: Carranza's Clinical Periodontology, 12th Edition, Page no: 524

When the flaps are not in close apposition, following suturing technique is used:

 # When the flaps are not in close apposition, following suturing technique is used:
A. Direct or loop suture
B. Sling ligation
C. Anchor suture
D. Figure of 8 suture


The correct answer is D. Figure of 8 suture.

Interdental Ligation. Two types of interdental ligation can be used: the direct loop suture and the figure-eight suture. With the figure-eight suture, thread is placed between the two flaps. This suture is used when the flaps are not in close apposition as a result of apical flap position or nonscalloped incisions. This is simpler to perform than the direct ligation. The direct suture allows for a better closure of the interdental papilla. It should be performed when bone grafts are used or when close apposition of the scalloped incision is required.

Reference: Carranza's Clinical Periodontology, 12th Edition, Page no: 586 e1

All the following cements possess anticariogenic properties, EXCEPT:

 # All the following cements  possess anticariogenic properties, EXCEPT:
A. Silicate
B. Glass ionomer
C. Silicophosphate
D. Zinc oxide eugenol



The correct answer is D. Zinc oxide eugenol.

Anticariogenic property of cements makes the enamel (fluorapatite) resistant to acid mediated decalcification. Silica-phosphate has the highest fluoride content followed by silicate and GIC. Polycarboxylate has least fluoride content. They release fluoride throughout the life of restoration but rate of release decreases over time.

Tarnish generally occurs in the oral cavity due to:

 # Tarnish generally occurs in the oral cavity due to:
A. Formation of hard and soft deposits
B. Pigment producing bacteria
C. Formation of their oxides, sulphides or chlorides
D. All of the above



The correct answer is D. All of the above.

Tarnish: It is the surface discoloration or alteration of the surface finish or luster. It generally occurs due to formation calculus, plaque on the surface of the metal. It also occurs due to formation of oxides, sulfides or chlorides. Tarnish is the forerunner of corrosion.

Which of the following alloys exhibit superelasticity and shape memory

 # Which of the following alloys exhibit superelasticity and shape memory?
A. Nitinol
B. Beta titanium
C. Optiflex
D. Stainless steel



The correct answer is A. Nitinol.

The nickel-titanium alloys used in dentistry are based upon the equiatomic intermetallic compound NiTi, which contains 55% nickel and 45% titanium by weight. Orthodontic wire alloys contain small amounts of other elements, such as cobalt, copper, and chromium.

The alloy name “Nitinol” originally came from the two elements nickel (Ni) and titanium (Ti) and the Naval Ordnance Laboratory (NOL) where these alloys were developed. Superelasticity and shape memory are the properties exhibited by Nitinol.



Which die material has a hazardous (lethal) potential during fabrication?

 # Which die material has a hazardous (lethal) potential during fabrication?
A. Improved stone
B. Silver amalgam
C. Electrodeposited silver
D. Epoxy resin



The correct answer is C. Electrodeposited silver.

• Has a lethal potential due to the Electro usage of silver cyanide plated silver 
• Polysulphide impressions can be easily electro plated

The coefficient of thermal expansion of which of the following dental materials is the highest?

 # The coefficient of thermal expansion of which of the following dental materials is the highest?
A. Amalgam
B. Gold inlay
C. Silicate cement
D. Acrylic resins


The correct answer is D. Acrylic resins.

Linear coefficient of thermal expansion (α = coefficient of linear expansion (°C−1))
Tooth 9 - 11
Silicate 8
Unfilled acrylate 81
Composites 28 - 45
Amalgam 25
Direct gold 18
Aluminous porcelain 6 - 7

The glass ionomer cement is not recommended for:

 # The glass ionomer cement is not recommended for:
A. Class V restoration
B. Class III restoration
C. Class IV restoration
D. None of the above



The correct answer is C. Class IV restoration 

INDICATIONS OF GIC
- The restoration of caries lesions on the roots of patients with active caries is the primary indication for the use of a glass ionomer as a restorative material.
- Because of their limited strength and wear resistance, glass ionomers are indicated generally for the restoration of low-stress areas (not for typical Class I, II or IV restorations), where caries activity potential is of significant concern.
- In addition to being indicated for root-surface caries lesions in Class V locations, slot-like preparations in Class II or III cervical locations (not involving the proximal contact) may be restored with glass ionomers, if access permits.
- Cervical defects of idiopathic erosion or abrasion origin (or any combination) also may be indications for restoration with glass ionomers, if esthetic demands are not critical.

 Reference: Sturdevant’s Art and Science of Operative Dentistry Second South Asia Edition 2019, Page No: 540



Antibiotic prophylaxis is not recommended in:

 # Antibiotic prophylaxis is not recommended in:
a) Making of impressions 
b) Dental extraction
c) Replantation of tooth 
d) Gingivectomy


The correct answer is A. Making of impressions.

All dental procedures that involve manipulation of gingival tissue or the periapical region of teeth or perforation of the oral mucosa need antibiotic prophylaxis to prevent Bacterial endocarditis. Procedures such as anesthetic injections through non infected areas, taking dental radiographs, placement of removable prosthodontic/orthodontic appliances, adjustment of ortho appliances, placement of brackets, shedding of deciduous teeth, bleeding from trauma to lips or oral mucosa do not need antibiotic prophylaxis.

Cardiac conditions requiring prophylaxis include prosthetic cardiac valve, previous infective endocarditis, congenital heart disease, cardiac transplantation recipients who develop cardiac valvulopathy. They may be given oral Amoxicillin 2 gm/ Azithromycin SOOmg/ Cephalexin 2gm/ Clindamycin 600mg (OR) Ampicillin 2 gm IM or IV/ Cefazolin or Ceftriaxone 1 gm IM or IV/ Clindamycin phosphate 600mg IM or IV.


# Serial extraction is contraindicated in:

 # Serial extraction is contraindicated in:
A. Open bite
B. Deep bite
C. Class II and III malocclusion with skeletal abnormalities
D. All of the above



The correct answer is D. All of the above.

Contraindications to Serial Extraction are:
1. Mild to moderate crowding—tooth size arch length deficiency < 5 mm per quadrant.
2. Class II division 2 and Class III malocclusions.
3. Spaced dentition.
4. Congenital absence—anodontia/oligodontia.
5. Extensive caries involving permanent first molars, which cannot be conserved.
6. Open bite and deep bite, which should be corrected first.

Reference: Textbook of Orthodontics, 2nd Edition, Gurkeerat Singh, Page No: 569

Pericision is carried out as an adjunct retention for:

 # Pericision is carried out as an adjunct retention for:
A. Midline diastema
B. Rotation
C. Proclination
D. Extrusion



The correct answer is B. Rotation.

It is generally assumed that a stable position of the teeth in the dental arch after orthodontic tooth
movement can only be established when the connective tissues of the gingiva have been allowed to adapt to the newly created situation. Supracrestal gingival fibers of an orthodontically moved tooth get
stretched and undergo readaptation very slowly. The pull of these fibers is a major factor in relapse. If these supracrestal fibers are sectioned and allowed to heal while the teeth are held in the proper position, relapse caused by gingival elastic fibers is greatly reduced.

Reattachment of these fibers at a new relaxed position on the root surface stabilizes the tooth in its new
position. This procedure is effective in controlling relapse of derotated teeth.

Reference: Textbook of Orthodontics, 2nd Edition Gurkeerat Singh, Page 279

Anterior crossbite should be corrected:

 # Anterior crossbite should be corrected:
A. During mixed dentition
B. After all permanent teeth have erupted
C. As soon as possible
D. Any time


The correct answer is C. As soon as possible.

Lingually positioned incisors limit lateral jaw movements and they or their mandibular counterparts sometimes suffer significant incisal abrasion, so early correction of the crossbite is indicated.

Early correction of dental cross bites in the mixed dentition is recommended because it eliminates functional shifts and wear on the erupted permanent teeth, and possibly dentoalveolar asymmetry. There are three basic approaches to the treatment of moderate posterior crossbites in children:
i) Equilibration to eliminate mandibular shift
ii) Expansion of a constricted maxillary arch, and
iii) Repositioning of individual teeth to deal with intra-arch asymmetries.

Reference: Contemporary Orthodontics, Proffit, 4th Edition Page no 248

# If the permanent canines are lost prematurely, the permanent incisors may drift:

 # If the permanent canines are lost prematurely, the permanent incisors may drift:
A. Labially
B. Distally
C. Medially
D. Lingually


The correct answer is B. Distally.

When a primary first molar or canine is lost prematurely, there is also a tendency for the space to close. This occurs primarily by distal drift of incisors, not by mesial drift of posterior teeth. The impetus for distal drift appears to have two sources: force from active contraction of transseptal fibers in the gingiva, and pressures from the lips and cheeks. 

Reference: Contemporary Orthodontics, 4th Edition, Profitt, Page no. 140

Final determination of the dental arch form depends on:

 # Final determination of the dental arch form depends on:
A. Angle’s classification
B. Growth pattern
C. Facial type
D. Balance between extraoral and intraoral muscle forces



The correct answer is D. Balance between extraoral and intraoral muscle forces.

Although negative pressure is created within the mouth during sucking, there is no reason to believe that this is responsible for the constriction of the maxillary arch that usually accompanies sucking habits. Instead, arch form is affected by an alteration in the balance between cheek and tongue pressures. If the thumb is placed between the teeth, the tongue must be lowered, which decreases pressure by the tongue against the lingual of upper posterior teeth. At the same time, cheek pressure against these teeth is increased as the buccinator muscle contracts during sucking. Cheek pressures are greatest at the corners of the mouth, and this probably explains why the maxillary arch tends to become V -shaped with more constriction across the canines than the molars. A child who sucks vigorously is more likely to have a narrow upper arch than one who just places the thumb between the teeth.

Reference: Contemporary Orthodontics, 4th Edition, Proffit, Page NO. 152


Which is not a method of gaining space?

 # Which is not a method of gaining space?
A. Proximal stripping
B. Intrusion
C. Uprighting of molars
D. Derotation of posterior teeth



The correct answer is B. Intrusion.

 Space can be gained by:

A.  Non Extraction 
 Proximal stripping 
 Arch expansion 
 Molar teeth distalization 
 Uprighting of tilted teeth 
 Derotation of posterior teeth 
 Proclination of anterior teeth

B. Extraction 
 Balancing extractions 
 Compensating extractions 
 Phased extractions 
 Enforced extractions 
 Wilkinson extractions 
 Therapeutic extractions


C. Surgical 
 Orthognathic surgery 
 Distraction osteogenesis


How much root formation is complete when tooth erupts into the oral cavity?

 # How much root formation is complete when tooth erupts into the oral cavity?
A. 100%
B. 75%
C. 60%
D. 50%
 


The correct answer is B. 75%.

The eruption of a permanent tooth can be delayed if its primary predecessor is retained too long. When this happens, the obvious treatment is to remove the primary tooth. As a general guideline, a permanent tooth should erupt when approximately three-fourths of its root is completed. If root formation of the permanent successor has reached this point while a primary tooth still has considerable root remaining, the primary tooth should be extracted.

Reference: Contemporary Orthodontics, Fourth Edition, Proffit, Page 249

Which of the following cephalometric values should decrease for an individual between the ages of 8 and 18 years?

 # Which of the following cephalometric values should decrease for an individual between the ages of 8 and 18 years?
A. FMA
B. ANB
C. GoGn-SN
D. All of the above



The correct answer is D. All of the above. 

With the possible exception of those who have an openbite malocclusion, patients who have a Frankfort mandibular angle (FMA) within the normal range can generally be expected to show a reduction in this angle with continued growth. If, during orthodontic treatment, the FMA increases, then it may be expected to return to its former relationship, or less, if the patient continues to grow. If no further growth takes place, then the return to the original FMA will likely not occur. If, however, further growth occurs and the maxillary and mandibular teeth are retained in a position of minimal overbite, then the subsequent increase in posterior facial height and a leveling of the FMA may occur without an accompanying increase or relapse in the deep overbite.

The magnitude of the ANB angle, however, is influenced by two factors other than the anteroposterior difference in jaw position. One is the vertical height of the face and the second is that if the anteroposterior position of nasion. During growth, as the vertical height of face occurs, ANB angle decreases generally.



Gingival involvement is an unusual finding in one of the following conditions?

 # Gingival involvement is an unusual finding in one of the following conditions?
A. Recurrent aphthae
B. Pemphigoid
C. Primary herpes
D. Pyogenic granulomas


The correct answer is A. Recurrent aphthae. 

The first episodes of RAS most frequently begin during the second decade of life. The lesions are confined to the oral mucosa and begin with prodromal burning or the sensation of a small bump in the mucosa from 2 to 48 hours before an ulcer appears. During this initial period, a localized area of erythema develops. Within hours, a small white papule forms, ulcerates, and gradually enlarges over the next 48–72 hours. The individual lesions are round, symmetric, and shallow (similar to viral ulcers), but no tissue tags are present from ruptured vesicles, which helps distinguish RAS from diseases that start as vesicles, such as pemphigus, and pemphigoid. Multiple lesions are often present, but the number, size, and frequency vary considerably.

The buccal and labial mucosae are most commonly involved. Lesions rarely occur on the heavily keratinized palatal mucosa or gingiva. In mild RAS, the lesions reach a size of 0.3–1.0 cm and begin healing within a few days. Healing without scarring is usually complete in 10–14 days.

Reference: Burket’s Oral Medicine, 12th Edition Page no 75

Dietary Approaches to Stop Hypertension - DASH Diet

 High blood pressure or Hypertension is blood pressure higher than normal. Blood pressure is expressed in A/B form where A is systolic pressure and B is diastolic pressure. High blood pressure is blood pressure above 140/90 mm Hg. Uncontrolled hypertension can lead to heart and kidney disease, stroke and blindness. But researches have shown that high blood pressure can be prevented by following the Dietary Approaches to stop Hypertension (DASH) eating plan. Dietary Approaches to Stop Hypertension (DASH) diet originated in the 1990s.




Many researches were conducted in 1992 by National Institute of Health to find the effectiveness of DASH eating plan. The research concluded that dietary interventions alone can lower systolic blood pressure by 6-11 mm Hg. The DASH diet offer an alternative to drug therapy in hypertensives and may prevent hypertension in normotensives. In a study done in 2014,the DASH diet was found to result in significant decreases in systolic BP ( − 5·2 mmHg, 95 % CI − 7·0, − 3·4; P< 0·001) and diastolic BP ( − 2·6 mmHg, 95 % CI − 3·5, − 1·7; P< 0·001). These changes predicted a reduction of approximately 13 % in the 10-year Framingham risk score for CVD.

DASH includes consumption of fruits and vegetables, lean meat and fat free or low fat dairy products, whole grains, fish, poultry, beans, seeds, and nuts and foods rich in nutrients —mainly potassium, magnesium, calcium, protein, and fiber. It also limits the intake of sodium in the diet to 1500 mg/day. DASH emphasizes on decrease consumption of processed food and increase consumption of fresh food.

DASH plan is as follows:
1.Vegetables: about five servings per day
2.Fruits: about five meals per day 
3.Carbohydrates: about seven servings per day

Healthy carbohydrates included under DASH include:
Green leafy vegetables: kale, broccoli, spinach, mustards
Whole grains: cracked wheat, millets, oats
Low glycemic index fruits
Legumes and beans

4.Low-fat dairy products: about two servings per day
DASH includes good fats. Good fat prevent inflammation and help in promotion of health. These fats increase HDL and decrease LDL.
- Olive oil
- Avocados
- Nuts
- Hempseeds
- Flax seeds
- Fish rich in omega-3 fatty acids

5.Lean meat products: about two or fewer servings per day
6.Nuts and seeds: 2 to 3 times per week

The DASH diet contains large amount of fiber and can cause bloating and diarrhoea. To avoid these problems, gradually increase the fruit, vegetables and whole grains in your diet over the weeks. Make these changes over a couple of days or weeks.
1.Add a serving of vegetables at lunch one day and dinner the next, and add fruit at one meal or as a snack.
2.Increase your use of fat-free and low-fat milk products to two servings a day.
3.Limit lean meats to 6 ounces a day—3 ounces a meal.
DASH diet helps you to control blood pressure and stay healthy. It helps to keep metabolic syndromes in check. Compliance to DASH has been associated with improvements of outcomes in type 2 Diabetes.

Know about JNC-8 Recommendations for Hypertension in the following video:


X ray beam is filtered to:

 # X ray beam is filtered to:
A. Soften the beam
B. Restrict beam size
C. Remove long wavelength  X rays
D. Remove short wavelength x rays



The correct answer is C. Remove long wavelength X rays.

Although an x-ray beam consists of a continuous spectrum of x-ray photon energies, only photons with sufficient energy to penetrate through anatomic structures and reach the image receptor (digital or film) are useful for diagnostic radiology. Low-energy photons that cannot reach the receptor contribute to patient risk but do not offer any benefit. Consequently, it is desirable to remove these low-energy photons from the beam. This removal can be accomplished in part by placing a metallic disk (filter) in the beam path. A filter preferentially removes low-energy photons from the beam, while allowing high-energy photons that are able to contribute to making an image to pass through.

Energy of x-rays depends directly on its frequency (E~f) and inversely related to wavelength (E~1/λ). Electromagnetic waves with higher frequencies have proportionally higher energies. The wave with the shorter wavelength, will have higher frequency. Since we know that the energy scales directly with the frequency we know that the wave that has the shorter wavelength will have higher energy.

Reference: Oral Radiology Principles and Interpretation, 7th Edition, White and Pharoah, Page no 10

Light appearing X ray film

 # Which of the following factor result in film appearing very  light?
A. Under exposure
B. Over development
C. Developing solution too hot
D. Unsafe illuminations in dark room



The correct answer is A. Underexposure.

CAUSE S OF LIGHT RADIOGRAPHS
Processing Errors
- Underdevelopment (temperature too low; time too short; thermometer inaccurate)
- Depleted developer solution
- Diluted or contaminated developer
- Excessive fixation

Underexposure
- Insufficient mA
- Insufficient kVp
- Insufficient time
- Film-source distance too great
- Film packet reversed in mouth 

Reference: Oral Radiology Principles and Interpretation, 7th Edition, White and Pharoah, Page no 80

Initial clinical sign of juvenile periodontitis:

 #  Initial clinical sign of juvenile periodontitis:
A. Pathological tooth migration and midline diastema
B. Tooth mobility and bone loss
C. Gingival enlargement and pus formation
D. Pain and bleeding





The correct answer is A. Pathological tooth migration and midline diastema.

Pathologic migration may continue after a tooth no longer contacts its antagonist. Pressures from the tongue, the food bolus during mastication, and the proliferating granulation tissue provide the force.

Pathologic migration is also an early sign of localized aggressive periodontitis. Weakened by the loss of periodontal support,the maxillary and mandibular anterior incisors drift labially and extrude, thereby creating diastemata between the teeth.

Reference: Carranza's Clinical Periodontology, 12th Edition, Page no: 306

In initial stages, treatment of acute necrotizing ulcerative gingivitis without systemic involvement is:

 # In initial stages, treatment of acute necrotizing ulcerative gingivitis without systemic involvement is:
A. Thorough debridement and H2O2 mouthwashes
B. Penicillin therapy
C. Metronidazole and penicillin therapy
D. Gingivectomy and gingivoplasty



The correct answer is A. Thorough debridement and H2O2 mouthwashes.

The oral cavity is examined for the characteristic lesion of NUG, its distribution, and the possible involvement of the oropharyngeal region. Oral hygiene is evaluated, with special attention to the presence of pericoronal flaps, periodontal pockets, and local factors (e.g., poor restorations, distribution of calculus). Periodontal probing of NUG lesions is likely to be very painful and may need to be deferred until after the acute lesions are resolved.

The goals of initial therapy are to reduce the microbial load and remove necrotic tissue to the degree that repair and regeneration of normal tissue barriers are reestablished.

Reference: Carranza's Clinical Periodontology, 12th Edition, Page no: 460

The extraoral radiograph that best shows the maxillary sinuses is:

 # The extraoral radiograph that best shows the maxillary sinuses is:
A. AP skull
B. Lateral skull
C. Towne’s view
D. Waters’ view


The correct answer is D. Waters' view.

This technique is useful for the evaluation of maxillary sinuses and it also demonstrates frontal sinuses, ethmoidal sinuses, orbit, zygomaticofrontal suture and nasal cavity. In Waters’ technique the neck is hyperextended enough to place the dense petrosae immediately below the maxillary sinus floor.

X rays were discovered in the year:

 # X rays were discovered in the year:
A. 1890
B. 1895
C. 1900
D. 1905



The correct answer is B. 1895.

 X-radiation is referred to as Röntgen radiation, after the German scientist Wilhelm Conrad Röntgen, who discovered it on November 8, 1895. He named it X-radiation to signify an unknown type of radiation.

Candidiasis - Clinical types and Treatment

 Candidiasis is a disease caused by infection with a yeast like fungus, Candida albicans, although other species may also be involved, such as C. tropicalis, C. parapsilosis, C. stellatoidea, C. krusei, C. glabrata, C. pseutropicalis and C. guilliermondii. Candidiasis is the most common opportunistic infection in the world. Its occurrence has surged since the prevalent use of antibiotics, which destroy the normal inhibitory bacterial flora, and immunosuppressive drugs, particularly corticosteroids and cytotoxic drugs. Oral candidiasis or oral thrush usually remain as a localized disease, but on occasion it may show extension to the pharynx or even to the lungs. 

Some specific conditions that may predispose a patient to develop oral candidiasis are:
❍ Factors that alter the immune status of the host
❍ Diabetes mellitus
❍ Corticosteroid therapy/hypoadrenalism
❍ Blood dyscrasias or advanced malignancy
❍ Old age/infancy
❍ Radiation therapy/chemotherapy
❍ HIV infection or other immunodeficiency disorders
❍ Endocrine abnormalities
❍ Hypothyroidism or hypoparathyroidism
❍ Pregnancy

Clinical presentation
Acute pseudomembranous candidiasis:  Pseudomembranous candidiasis is the most common form of oral candidiasis. The most common sites of occurrence include buccal mucosa, dorsal tongue and palate. It is usually seen after antibiotic therapy or immunosuppression. A burning sensation usually
precedes the appearance of soft, creamy white to yellow, elevated plaques, that are easily wiped off from the affected oral tissues and leave an erythematous, eroded, or ulcerated surface which may be tender. Candidiasis may be seen in neonates and among terminally ill patients, particularly in association with serious underlying conditions such as leukemia and other malignancies and in HIV
disease.

Chronic hyperplastic candidiasis: (candida leukoplakia) Hyperplastic candidiasis is seen as chronic, discrete raised lesions that vary from small, palpable translucent whitish areas to large, dense, opaque plaques, hard and rough to touch. The most common sites are the anterior buccal mucosa along the occlusal line, and laterodorsal surfaces of the tongue. The most common appearance is that of asymptomatic white plaques or papules (sometimes against an erythematous background) that are adherent and do not scrape off.

Chronic atrophic (erythematous) candidiasis:  The most common site is the hard palate under a denture
but atrophic candidiasis may also be found on the dorsal tongue and other mucosal surfaces. The most common etiology is poor denture hygiene, and/or continuous denture insertion, but it may also be caused by immunosuppression, xerostomia, or antibiotic therapy.

Median rhomboid glossitis: Median rhomboid glossitis is a form of chronic atrophic candidiasis characterized by an asymptomatic, elongated, erythematous patch of atrophic mucosa of the posterior mid-dorsal surface of the tongue due to a chronic Candida infection. In the past, median rhomboid glossitis was thought to be a developmental defect resulting from a failure of the tuberculum impart to retract before fusion of the lateral processes of the tongue. 

Angular cheilitis (perleche): Clinical appearance is that of red, eroded, fissured lesions which occur bilaterally in the commissures of the lips and are frequently irritating and painful. The most common etiology is loss of vertical occlusal dimension, but it may also be associated with immunosuppression.

Chronic multifocal oral candidiasis: This term has been given to chronic candidal infection that may be seen in multiple oral sites, with various combinations, including angular stomatitis, median rhomboid glossitis and palatal lesions.

Chronic mucocutaneous candidiasis (CMC): It is the term given to the group of rare syndromes, with  definable immune defects, in which there is persistent mucocutaneous candidiasis that responds poorly to topical antifungal therapy.

Treatment: 
Topical versus systemic drugs Topical antifungals are usually the drug of choice for uncomplicated, localized candidiasis in patients with normal immune function. Systemic antifungals are usually indicated in cases of disseminated disease and/or in immunocompromised patients.

Topical antifungal medications: Nystatin is the first specific antifungal agent effective in the treatment of candidiasis.

Nystatin oral suspension 100,000 units/ml; 300 ml: rinse with one teaspoonful (5 ml) for 2 minutes, use q.i.d. (after meals, and at bedtime) and spit out. Patient can be directed to rinse and swallow if there is
pharyngeal involvement.

Amphotericin B - a cornerstone of therapy for systemic fungal infections.
Clotrimazole - most potent topical agent in azole group of antifungals. 10 mg 70 troches; one troche dissolved in mouth five times per day for 14 days.

Systemic antifungal medications 
Ketoconazole tablets, 200 mg 1 tab q.i.d. with a meal or orange juice for 14 days. Ketoconazole is the drug being used in the treatment of chronic mucocutaneous candidiasis and candidiasis
in immunocompromised patients.

Fluconazole tablets, 100 mg, 15 tablets; 2 tablets to start, then 1 tablet q.i.d. for 14 days, oral absorption of fluconazole is rapid and nearly complete within 2 hours.

Itraconazole tablets, 100 mg, 1 tablet b.i.d. with a meal or orange juice for 14 days. This drug has a long half-life and fewer side effects than ketoconazole but is expensive. Its use is contraindicated in liver diseases.

Treatment for chronic atropic candidiasis Application of a thin coat of medicines like nystatin ointment or clotrimazole cream 1% or miconazole cream 2%, ketoconazole cream 2% to entire inner surface of denture after each meal for 14 days usually results in remission. Patient should be instructed to leave dentures out at night and to soak denture in a 1% sodium hypochlorite solution for 15 minutes with thorough rinsing under running water for at least 2 minutes, before bedtime.

Nystatin–triamcinolone acetonide ointment or clotrimazole cream 1% or miconazole cream 2% or ketoconazole cream 2% can be applied to affected areas q.i.d. (after meals, and at bedtime) for 14 days.




Areas anesthetized by the intraoral inferior alveolar nerve block include:

 # Areas anesthetized by the intraoral inferior alveolar nerve block include:
A. The body of the mandible
B. The inferior portion of the ramus
C. Mandibular teeth
D. All of the above



The correct answer is D. All of the above.

Areas Anesthetized by Inferior alveolar nerve block
1. Mandibular teeth to the midline
2. Body of the mandible, inferior portion of the ramus
3. Buccal mucoperiosteum, mucous membrane anterior to the mental foramen (mental nerve)
4. Anterior two thirds of the tongue and floor of the oral cavity (lingual nerve)
5. Lingual soft tissues and periosteum (lingual nerve)

Ref: Handbook of Local Anesthesia, Malamed, 6th Edition, Page 227


For a successful intraoral palatal second divisions nerve block anesthesia, the needle should enter the:

 # For a successful intraoral palatal second divisions nerve block anesthesia, the needle should enter the:
A. Incisive canal
B. Infraalveolar foramen
C. Greater palatine foramen
D. Stylomastoid foramen



The correct answer is C. Greater palatine foramen.

Area of insertion: palatal soft tissue directly over the greater palatine foramen
Target area: the maxillary nerve as it passes through the pterygopalatine fossa; the needle passes through the greater palatine canal to reach the pterygopalatine fossa

Ref: Handbook of Local anesthesia, Malamed, 6th Edition Page 220


The first line of treatment in a patient with syncope due to local anesthesia is administration of:

 # The first line of treatment in a patient with syncope due to local anesthesia is administration of:
A. Oxygen
B. Respiratory stimulant
C. Adrenaline
D. Diazepam



The correct answer is A. Oxygen.

Definitive care after syncopal attack:
-Administer O2
- Monitor vital signs
- Perform additional procedures: Administer aromatic ammonia vaporole; Administer “sugar” (e.g., orange juice, non-diet soft drink)
- Administer atropine if bradycardia persists
- Do not panic!

Reference: Medical Emergencies in the Dental Office, Malamed, 7th edition Page no: 151

What is the fate of nitrous oxide when administered for relative analgesia?

 # What is the fate of nitrous oxide when administered for relative analgesia?
A. Excreted by kidney
B. Detoxified in liver
C. Exhaled by lungs
D. Exhaled by sweat glands



The correct answer is C. Exhaled by lungs.

As the sole agent, N2O (50%) has been used with O2 for dental and obstetric analgesia. It is
nontoxic to liver, kidney and brain. However, prolonged N2O anaesthesia has the potential to
depress bone marrow and cause peripheral neuropathy. Metabolism of N2O does not occur;
it is quickly removed from the body by lungs. It is cheap and commonly used.

Reference: Essentials of Medical Pharmacology, KD Tripathi, Seventh edition page no 378

Hematoma formation after posterior superior alveolar nerve block

 # If hematoma formation occurs after posterior superior alveolar nerve block, it is due to the damage of:
A. Pterygoid venous plexus
B. Small capillaries and arterioles in the region
C. Facial artery
D. Internal maxillary artery



The correct answer is A. Pterygoid venous plexus.

Complications after posterior superior alveolar nerve block
1. Hematoma:
a. This is commonly produced by inserting the needle too far posteriorly into the pterygoid plexus of veins. In addition, the maxillary artery may be perforated. Use of a short needle minimizes the risk of pterygoid plexus puncture.

b. A visible intraoral hematoma develops within several minutes, usually noted in the buccal tissues of the mandibular region.
(1) There is no easily accessible intraoral area to which pressure can be applied to stop the hemorrhage.
(2) Bleeding continues until the pressure of extravascular blood is equal to or greater than that of intravascular blood.

Reference: Handbook of Local Anesthesia, Malamed, 6th Edition, Page 195

AIIMS NOVEMBER 2015 MDS PAST ENTRANCE EXAM MCQs


# Medial dislocation of fractured condyle in subcondylar fracrure is caused by:
A. Medial pterygoid
B. Lateral pterygoid
C. Masseter
D. Buccinator

# A dental surgeon has recoverd from Hepatitis B by 3 months rest. His laboratory findings are normal but he is not allowed to attend patients as per medical board as he is:
A. healthy carrier
B. active carrier
C. convalescent carrier
D. paradoxical carrier

AIIMS NOVEMBER 2014 MDS ENTRANCE EXAM PAST QUESTIONS


# Which of the following is not seen in posterior triangle of neck:
A. Hypoglossal nerve
B. Subclavein vein
C. External jugular vein
D. Phrenic nerve

# Which of the following is derived from second brachial arch:
A. muscle of facial expression
B. masticatory muscles
C. mandible
D. condyle

The duration of fixation generally required for fracture of mandible:

 # The duration of fixation generally required for fracture of mandible:
A. 2-4 weeks
B. 3-5 weeks
C. 6-8 weeks
D. 8-10 weeks



The correct answer is C. 6-8 weeks.

In the past, one of the major considerations in the immediate postoperative period was the difficulty resulting from IMF. When  the jaws are wired together, the patient has initial difficulties in obtaining adequate nutrition, performing necessary oral hygiene, and communicating verbally. The average IMF period ranges from 6 to  8 weeks.

Reference: Contemporary Oral and Maxillofacial Surgery, James R. Hupp, 6th Edition 2013, Page No:  557


Tonsillitis - Causes and Treatment

 Tonsillitis


Inflammation of palatine tonsils is called tonsillitis. Each tonsil is a mass of lymphoid tissue at the back of your throat-one on each side.

What is the role of tonsils in our body?
It provides local immunity and surveillance to our body to fight against foreign intruders.

Tonsils are most active from 4 to 10 years of age. After puberty, gradual involution of the tonsils takes place..
Types:
1.Acute tonsillitis
2.Chronic tonsillitis




Etiology:
- Most common in school going children but may affect adult. Viruses are the most common offenders in tonsillitis.
1.Adenovirus
2.Influenza virus
3.Parainfluenza virus
4.Herpes simplex virus (HSV)

- Hemolytic streptococcus is a common bacteria causing tonsillitis. Other bacteria causing tonsillitis are:
1.Staphylococci
2.Pneumococci
3.Haemophilus Influenzae

What are the symptoms of Acute tonsillitis?
The most common symptoms of tonsillitis are:
1. Enlarged, red tonsils
2. Sore throat
3. Not able to swallow due to which drooling may occur
4. Fever
5. Ear pain
6. Abdominal pain in children
7. Headaches
8. General body aches 
9. Constipation

Diagnosis:
The doctor will do physical examination and look at your tonsils for signs of inflammation. A throat swab will be taken for culture. Growth of bacterial colony indicates bacterial tonsillitis. No growth will give a inference of viral disease.


Complications:
Complications will arise if the treatment is not provided or not adequate.
1.Collection of pus around tonsil (Peritonsillar abscess)
2. Infection may spread into surrounding tissues
3. Parapharyngeal abscess
4. Obstructive sleep apnea
5. Rheumatic fever if the causative agent is Group A beta-hemolytic streptococcus.
6. Glomerulonephritis


Treatment
1. Medical treatment
Antibiotics will be given if the culture shows growth of bacteria. Penicillin is the drug of choice. In patients with penicillin allergy, erythromycin can be given. If the cause is a virus then there is no role of antibiotics. With adequate bed rest and plenty of fluids body will recover on its own. Sometimes, your doctor may prescribe antibiotics in viral tonsillitis to prevent secondary bacterial infection. Paracetamol is given for fever and relief of pain. Prepare salt water solution at home and gargle the solution and spit it out.

2.Surgery
Removal of the tonsils (tonsillectomy) is required if there is recurrent tonsillitis. Recurrent tonsillitis is defined as;
- Seven or more episodes of tonsillitis in one year
- Five episodes per year for two consecutive year
- Three episodes per year for three consecutive year


A bony opening in the canine fossa is commonly used to:

 # A bony opening in the canine fossa is commonly used to:
A. Enter the maxillary sinus
B. Establish drainage of an alveolar abscess
C. Remove mandibular third molars
D. Uncover and marsupialize a cyst



The correct answer is A. Enter the maxillary sinus.

The wall of the sinus is very thin in this area. This area is used for following: (i) Diagnostic aspiration, and (ii) The site for Caldwell-Luc operation; that is, the antral exploration with or without an intraoral antrostomy.

Reference: Textbook of Oral and Maxillofacial Surgery, Third Edition, Neelima Anil Malik, Page no.  639


# Most frequent site for dry socket is:

 # Most frequent site for dry socket is:
A. Upper molar area
B. Upper incisor area
C. Lower molar area
D. Lower incisor area



The correct answer is C. Lower molar area.

'Dry socket' derives its name from the fact that after the clot is lost the socket has a dry appearance because of the exposed bone. This condition is more common in women and tobacco users, and is most frequently associated with difficult or traumatic extractions and thus most commonly follows removal of an impacted mandibular third molar. In a series of 138 ‘dry sockets’ among 6,403 teeth extracted in human patients, Krogh reported that 95% were in lower bicuspid and molar sockets, and this is confirmed by most other large series of cases.

Reference: Shafer’s Textbook of ORAL PATHOLOGY, 7th Edition, Page No:  601


Which one of the following is not a valid indication for apicoectomy?

 # Which one of the following is not a valid indication for apicoectomy?
A. Broken instrument in the apical third of the canal
B. Presence of a fistula
C. Perforation in apical third
D. Periapically involved teeth in patients with insufficient time for conventional endodontic treatment



The correct answer is D. Periapically involved teeth in patients with insufficient time for conventional endodontic treatment

Valid Indications for which apicoectomy can be considered are:
- Failure of nonsurgical endodontic treatment
- Failure of previous surgery
- Anatomical problems: non-negotiable or blocked canal, or severe root curvature
- Iatrogenic errors: ledging of canals, blockage from debris, separated instruments, overfilling of canals leading to foreign body reaction, and apical canal transportation
- Horizontal apical root fracture
- Exploratory surgery and biopsy: in teeth where a fracture is suspected or in teeth with vital pulp with a radicular radiolucency
- Periodontal considerations: Hemisection and radisection are planned in cases where the periodontal support of one of the roots goes beyond repair.

Reference: GROSSMAN’S ENDODONTIC PRACTICE 14TH EDITION, Page NO: 426