FREE NDEB Dental Sciences Questions and Answers
Dental porcelain has ________:
Explanation:
Dental porcelain exhibits high hardness, making it resistant to wear, but it has low impact strength, meaning it is prone to fracture or chipping under forceful impacts.
A patient has a history of radiation therapy for thyroid cancer. Three weeks after an extraction, there is increasing pain and a non-healing extraction socket with exposed sequestrated bone. The most likely diagnosis is _________:
Explanation:
In a patient with a history of radiation therapy, increasing pain and a nonhealing extraction socket with exposed bone suggest osteoradionecrosis, a complication characterized by bone death due to radiation-induced vascular damage.
An SNA of 88˚ most likely indicates a maxilla positioned ________:
Explanation:
An SNA angle of 88˚ indicates that the maxilla is positioned anteriorly relative to the cranial base.
Surface enamel is more highly mineralized than the rest of the enamel because _______:
Explanation:
Surface enamel is more highly mineralized than the rest of the enamel because the crystallites are deposited parallel to the surface, resulting in greater mineral density and hardness.
When prescribing codeine, patients should be informed ________:
Explanation:
Patients should be advised to avoid consuming alcohol while taking codeine because it can enhance the sedative effects of the medication and increase the risk of adverse reactions such as dizziness, drowsiness, and respiratory depression.
Which of the following is the most common cause of fracture of nickel-titanium (NiTi) rotary endodontic instruments?
Explanation:
Torsional stresses occur when the tip of the NiTi rotary endodontic instrument binds within the root canal, leading to excessive stress and potential fracture of the instrument.
When taking the working length radiograph for tooth 1.4 with 2 canals, the superimposition of the roots can be avoided by
Explanation:
To avoid superimposition of the roots when taking a working length radiograph for a tooth with two canals, such as tooth 1.4, the best approach is to change the horizontal angulation of the X-ray beam. Adjusting the horizontal angulation helps to separate the roots and provides a clearer view of each canal's position within the tooth.
Disinfection is a process that ______:
Explanation:
Disinfection is a process that aims to reduce the number of microorganisms, including bacteria, viruses, fungi, and protozoa, to a level where they are no longer harmful or pose a lower risk of infection or disease transmission.
Arterial blood flows continuously through capillaries during both systole and diastole because ________:
Explanation:
Arterial blood flows continuously through capillaries during both systole and diastole because arterioles, the small branches of arteries, can regulate their diameters to maintain blood flow and distribute blood appropriately to tissues.
A facial nerve injury at the stylomastoid foramen will result in _______:
Explanation:
The facial nerve, also known as the seventh cranial nerve, exits the skull through an opening called the stylomastoid foramen. This nerve innervates various muscles of the face, including those responsible for facial expressions and taste sensation on the anterior 2/3 of the tongue. Therefore, an injury to the facial nerve at the stylomastoid foramen would result in loss of taste sensation from the anterior 2/3 of the tongue.
Plaque becomes more cariogenic when ________:
Explanation:
Plaque becomes more cariogenic when acidogenic bacteria (those that produce acid) are present along with fermentable carbohydrates, as this combination promotes acid production, leading to demineralization of tooth structure and dental caries formation.