MDS PREP
Most frequent failures of root canal treated cases are due to
1. Inadequate obturation
2. Improper sterilization
3. Improper preparation
4. All of the above
Endodontics
Answer: 1
The most frequent failures of root canal treated cases are often due to
inadequate obturation. This can occur when the root canal filling material does
not completely fill the space or when it is not properly compacted, leaving gaps
where bacteria can persist and cause reinfection. Proper preparation and
sterilization are also crucial, but inadequate obturation is the most common
technical error leading to treatment failure.
Moderate extrusion of obturating material and sealer beyond the apex is undesirable because
1. The prognosis is poor
2. There is likelihood of postoperative discomfort
3. Sealer is usually not resorbed and gutta-percha may cause severe perirdicular reaction in periapical tissue
4. All of the above
Endodontics
Answer: 4
When moderate extrusion of obturating material and sealer beyond the apex
occurs, it is undesirable for several reasons. While it does not necessarily
mean the prognosis is poor, there is a higher likelihood of postoperative
discomfort due to the potential for chemical irritation of the periapical
tissues. Additionally, if the sealer is not resorbed, it may cause a foreign
body reaction, and gutta-percha extrusion can sometimes lead to severe
periradicular reactions. The best approach in such a case is to obturate the
remaining canal up to the point of obstruction and observe the patient's
symptoms and healing response.
Flare-ups during root canal treatment are commonly associated with which of the following
1. Teeth with vital pulp tissue compared to teeth with pulpal necrosis
2. Teeth with apical radiolucencies when compared to teeth with normal periapical tissue
3. With single-visit endodontics procedures
4. Symptomatic teeth exhibiting pulp necrosis
Endodontics
Answer: 4
Explanation: Flare-ups are more frequently observed in symptomatic teeth with
pulp necrosis due to the inflammatory response and the complexity of the root
canal system. This can lead to increased discomfort and complications during
treatment, necessitating careful management.
In periapical lesions of average size, time needed for osteogenesis is
1. 1-2 months
2. 2-6 months
3. 6-12 months
4. 2 weeks
Endodontics
Answer: 3
Osteogenesis in periapical lesions of average size generally requires a
significant amount of time, typically falling within the range of 6-12 months.
This period allows for the complete healing of bone tissue around the root apex.
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.
High heat obturation technique refers to
1) Thermofill technique
2) Ultrafill technique
3) Sectional filling
4) Obtura II technique
Endodontics
Answer: 4
Obtura II is a high heat obturation technique used in endodontics (root canal treatment) to fill and seal the root canal system of teeth. This technique involves the use of a thermoplasticized gutta-percha, which is heated to a high temperature and then compacted into the root canal with a heat source such as a heated plugger or a heated tip of a handpiece. The heat helps to soften the gutta-percha, allowing it to adapt to the irregularities of the root canal system and form a tight seal against bacterial microleakage. Thermofill and Ultrafill are not high heat techniques, while sectional filling is a method of filling the canal in increments, which may or may not involve heat.
The principal cone of gutta-percha used for condensation should
1. Fit exactly at apex
2. Have a definite apical seal
3. Fit loosely in the canal
4. Be 2 mm from the apex
Endodontics
Answer: 2
In endodontics, the primary goal of using gutta-percha is to achieve a proper seal at the apex of the root canal system. A definite apical seal is crucial to prevent the ingress of bacteria and fluids, which can lead to reinfection. While the cone should fit well within the canal, the emphasis is on achieving a good seal rather than merely fitting exactly at the apex or being 2 mm from it.
In hot bead sterilizer, temperature is highest in
1. Inner zone of the sterilizer
2. Outer zone of the sterilizer
3. Equal in both outer and inner zone
4. Variable
Endodontics
Answer: 2
In a hot bead sterilizer, the temperature is highest in the inner zone of the sterilizer. A hot bead sterilizer uses a heated metal bead to transfer heat to the instruments, which are placed around the bead in a basket. The inner zone is where the bead is located and where the temperature can reach up to 300°C, which is sufficient to kill microorganisms and sterilize the instruments. The outer zone is cooler and does not contribute significantly to the sterilization process.