The point at which the chlorine demand of water is met is termed:

 # The point at which the chlorine demand of water is met is termed:

A. Break point

B. Back wash

C. Loss of head

D. Chlorine demand

The correct answer is A. Break Point.

Chlorine demand of the water is the difference between the amount of chlorine added to the water and the amount of residual chlorine remaining at the end of a specific period of contact at a given temperature and pH of water.

The minimum recommended concentration of free chlorine is 0.5 mg per liter for one hour and it should be present for a contact period of at least one hour to kill bacteria and viruses. 

The point at which chlorine demand of water is met is called break point. If further chlorine is added beyond the break point, free chlorine begins to appear in the water. 

The sum of the chlorine demand of the water plus the free residual chlorine of 0.5 mg per liter constitutes the correct dose of chlorine to be applied. 

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The health promotional phase in public health is between the years:

 # The health promotional phase in public health is between the years:

A. 1880-1920

B. 1920-1960

C. 1960-1980

D. 1980-2000

The correct answer is B. 1920-1960.

Four phases of public health have been recognized:

A. Phase one: Disease Control Phase (1880-1920)

The 19th century Public Health- matter of sanitary legislation and sanitary reform, safe water supply and waste disposal. 

B. Phase Two: Health promotional phase (1920-1960)

At the beginning of the 20th century, the concept of health promotion emerged. As a result, in addition to disease control activities, one more goal was initiated. e.g. Maternal and child health, School health, mental health, occupational health and rehabilitation services.

C. Phase Three: Social Engineering phase (1960-1980)

Chronic conditions such as cancer, Diabetes mellitus (DM), cardiovascular diseases (CVD), and alcoholism, drug addiction occurred. These chronic health problems could not be tackled by the traditional approaches to public health i.e. isolation, immunization, and disinfection) nor they can be explained on the basis of germ theory (biomedical) of disease. The concept of risk factors (social, environmental, genetic and lifestyle) came into action as determinants of disease. 

D. Phase four: Health for all phase (1980-2000)

Primary Health care, Health for all (HFA)- Health for all meant that every individual should have access to Primary Health Care 

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WHO Oral Health Assessment Form Filled Samples

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Monomer in heat cure denture base acrylic resins

 # In heat cure denture base acrylic resins, the monomer is:

A. Methyl methacrylate

B. Ethyl methacrylate

C. Methyl ethyl methacrylate

D. Polymethyl methacrylate

The correct answer is A. Methyl methacrylate.

Most polymethyl methacrylate resin systems include powder and liquid components. The powder consists of prepolymerized spheres of polymethyl methacrylate and a small amount of benzoyl peroxide, termed the initiator, which is responsible for starting the polymerization process. The liquid is predominantly nonpolymerized methyl methacrylate monomer with small amounts of hydroquinone. Hydroquinone is added as an inhibitor, which prevents undesirable polymerization or “setting” of the liquid during storage. Inhibitors also retard the curing process and thereby increase working time.

Ref: Phillip’s Science of Dental Materials, 12th Edition, Page no. 475

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Esthetic Appliances for Orthodontic Treatment

 # In adults seeking orthodontic treatment with esthetic appliances the following may be choices EXCEPT:

a) Lingual orthodontics 

b) Ceramic brackets

c) Clear aligner therapy

d) Titanium brackets

The correct answer is D. Titanium brackets.

All other options are considered esthetic orthodontic appliances because they are either not visible or highly perceptible. Titanium brackets display metal and are not esthetic. Clear aligner therapy can be used for minor orthodontic corrections and can be preferred by patients due to esthetics and ease of use. 

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Rotated Maxillary Central Incisor

 # A child is brought to the clinic with complaint of irregular teeth. The maxillary central incisor is rotated in an otherwise normal occlusion. What should the next step be?

a) Check for supernumerary teeth

b) Resection of supracrestal fibers

c) Exert a couple on tooth

d) Fixed orthodontic appliances given  

The correct answer is a. Check for supernumerary teeth.

Unerupted mesiodens and the presence of thick labial frenum between the central incisors are common causes of midline diastema.

Before attempting to close midline diastema, radiographs should be taken to rule out supernumerary teeth as the cause of diastema.

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Agent approved as an immersion sterilant

 # Which of the following agents is approved as an immersion sterilant?

A. Ethyl alcohol

B. Glutaraldehyde

C. Iodophors

D. Sodium Hypochlorite

The correct answer is B. Glutaraldehyde.

Immersion sterilants are agents used to sterilize instruments by dipping them in their solution. 

Glutaraldehydes are used as a disinfectant and in fixing biological tissues for light and electron microscopy. This is the most widely used immersion sterilant. 

Glutaraldehyde, sold under the brandname Cidex and Glutaral among others, is a disinfectant, medication, preservative, and fixative. As a disinfectant, it is used to sterilize surgical instruments and other areas of hospitals.  As a medication, it is used to treat warts on the bottom of the feet. Glutaraldehyde is applied as a liquid.

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