MDS PREP
Term "apical collar" (or) "apical seat" refers to
1. Resistance form of canal preparation
2. Located in apical 2 mm with parallel walls
3. Mechanically prepared portion of root canal
4. All of the above
Endodontics
Answer: 4
There is a real relationship between the incidence of fractured anterior teeth and the
1) Caries in those teeth
2) Hardness of the enamel
3) Hardness of the dentin
4) Protrusion of those teeth
Endodontics
Answer: 4
The protrusion of anterior teeth can increase the risk of fractures due to their position and exposure to occlusal forces. Protruded teeth are more susceptible to trauma and stress during biting and chewing, which can lead to fractures. Additionally, protruded teeth may not have adequate support from adjacent teeth, further increasing their vulnerability to fracture.
Activity of disinfectants is
1) Reduced by organic debris or blood
2) Increased with heat
3) Hastened by adding 5 % oxygen
4) Nullified by ethylene dioxide gas
Endodontics
Answer: 1
Activity of disinfectants is indeed reduced by organic debris or blood. This is because organic materials can act as a barrier, protecting microorganisms from the disinfectant and reducing its effectiveness. The presence of organic matter can bind to the disinfectant, inactivate it, or consume it, thereby reducing its ability to kill or inhibit the growth of microorganisms. For this reason, it is essential to thoroughly clean and debride the area before applying a disinfectant to ensure optimal efficacy.
The disadvantage of glass bead sterilizer
1) Only small instruments can be sterilized
2) Variable temperature
3) Does not produce effective heat for sterilization
4) All of the above
Endodontics
Answer: 1
Explanation:
One of the main disadvantages of glass bead sterilizers is that they are limited to sterilizing only small instruments due to the size of the sterilization chamber. Larger instruments cannot be effectively sterilized in this type of device.
Which of the following statements is false?
1) The upper first premolar usually has two canals
2) Root canal instruments are best sterilized by a chemical method
3) All root canals must be enlarged to at least a size 25 file
4) All are false
Endodontics
Answer: 2
1) The upper first premolar usually has two canals: This statement is true. While the presence of two canals in the upper first premolar is not guaranteed, it is quite common to find two canals in this tooth.
2) Root canal instruments are best sterilized by a chemical method: This statement is false. The best method for sterilizing root canal instruments is heat sterilization using an autoclave. Chemical methods can be used for surface disinfection but are not adequate for sterilization.
3) All root canals must be enlarged to at least a size 25 file: This statement is true. Enlarging the root canals to a size 25 or larger is a part of the cleaning and shaping process in root canal therapy to ensure thorough debridement and preparation for filling.
Gutta-percha cones should not be used for root canal filling in
1. Primary teeth
2. Permanent mandibular last molars
3. Teeth with wide root canal
4. Teeth with curved roots
Endodontics
Answer: 1
Gutta-percha cones are generally not recommended for root canal filling in
primary teeth because the root canals of primary teeth are more likely to
contain vital tissue, and the material can potentially cause harm to these
tissues. However, they are suitable for permanent teeth with wide root canals
and even those with curved roots, provided that the root canals are properly
cleaned and shaped to allow for optimal filling.
Operator can identify root curvatures ledgings an additional curvatures by
1. Perception by instrumentation
2. Radiographic examination
3. By his knowledge of tooth anatomy
4. None of the above
Endodontics
Answer: 1
Identifying Root Curvatures
Perception by instrumentation refers to the tactile
feedback that a dentist can obtain while using instruments during
procedures, allowing them to identify curvatures in the root canal system.
According to WHO nomenclature of pulp injuries, "avulsion" is classified of pulp injuries as
1. 873.60
2. 873.61
3. 873.68
4. 873.69
Endodontics
Answer: 2
Explanation: In the WHO classification, avulsion refers to the complete
displacement of a tooth from its socket, and it is classified under 873.61. This
classification is crucial for understanding the severity of the injury and
determining the appropriate treatment.