What tends to maintain the integrity of a bone implant interface?

 

# _______ tend to maintain the integrity of a bone implant interface:

a. Compressive force 

b. tensile force 

c. Shear force 

d. All the above 

The correct answer is A. Compressive force.

Forces may be described as compressive, tensile, or shear. Compressive forces attempt to push masses toward each other. Tensile forces pull objects apart. Shear forces on implants cause sliding. Whereas compressive forces tend to maintain the integrity of a bone–implant interface, tensile and shear forces tend to distract or disrupt such an interface. Shear forces are most destructive to implants and bone compared with other load modalities. In general, compressive forces are accommodated best by the complete implant–prosthesis system. Cortical bone is strongest in compression and weakest in shear.

Atherosclerosis is due to:

 # Atherosclerosis is due to 

a. HDL receptor defect 

b. apolipoprotein E deficiency 

c. decreased LDL activity 

d. decreased lipoprotein lipase 

The correct answer is B. Apolipoprotein E deficiency.

Apolipoprotein (apo) E is recognized for its unparalleled ability to suppress atherosclerosis .The expression of apoE in the macrophage has long been recognized to suppress atherosclerosis by preventing foam cell formation in the vessel wall.

APOE was initially recognized for its importance in lipoprotein metabolism and cardiovascular disease. Defects in APOE result in familial dysbetalipoproteinemia aka type III hyperlipoproteinemia (HLP III), in which increased plasma cholesterol and triglycerides are the consequence of impaired clearance of chylomicron, VLDL and LDL.

An amalgam restoration is considered:

 # An amalgam restoration is considered _____.

A. Primary prevention

B. Secondary prevention

C. Tertiary prevention

D. Both primary and tertiary prevention

The correct answer is B. Secondary prevention.

Secondary prevention is the elimination or reduction of a disease after it occurs. An amalgam restoration is considered secondary prevention because tooth decay is removed and a restoration is placed. 

Amount of fluoride in smear size toothpaste for children age less than 3 years:

 # Amount of fluoride in smear size toothpaste for children age less than 3 years: 

a. 0.1mg 

b. 0.2 mg 

c. 0.5 mg 

d. 1 mg 

The correct answer is A. 0.1 mg.

For children younger than 3 years, caregivers should begin brushing children's teeth as soon as they begin to come into the mouth by using fluoride toothpaste in an amount no more than a smear or the size of a grain of rice. Teeth should be brushed thoroughly twice per day (morning and night) or as directed by a dentist or physician. Children's brushing should be supervised to ensure that they use the appropriate amount of toothpaste.

Source: AAPD recommendation 2021

A person with glaucoma should not receive:

 # A person with glaucoma should not receive: 

a. Sedatives 

b. Vasoconstrictors 

c. Anti-sialogogues 

d. Local anesthetics 

The correct answer is C. Anti-sialogogues.

Antimuscarinic mydriatics like tropicamide, cyclopentolate, etc. produce both mydriasis and cycloplegia, and tend to raise i.o.p. in glaucoma patients. Therefore, antimuscarinics are to be avoided in glaucoma patients. 

Procedure necessary to preserve and restore anterior guidance

 # A dentist is preparing all maxillary anterior teeth for metal-ceramic crowns. Which of the following procedures is necessary to preserve and restore anterior guidance? 

A. Protrusive record 

B. Template for provisional restorations 

C. Custom incisal guide table 

D. Interocclusal record in centric relation 

The correct answer is C. Custom incisal guide table.

Anterior guidance must be preserved by means of construction of a custom incisal guide table, especially when restorative procedures change the surfaces of anterior teeth that guide the mandible in excursive (lateral, protrusive) movements. 

A cyst formed when the stellate reticulum degenerates:

 # A cyst formed when the stellate reticulum degenerates: 

a. Eruption cyst 

b. Dentigerous cyst 

c. Keratocyst 

d. Radicular cyst 

The correct answer is A. Eruption cyst.

An eruption cyst is a type of dentigerous cyst formed when the stellate reticulum degenerates, leaving a cavity lined by the outer enamel epithelium before or during tooth eruption.

Eruption cyst is defined as an odontogenic cyst with the histologic features of a dentigerous cyst that surrounds a tooth crown that has erupted through bone but not soft tissue and is clinically visible as a soft fluctuant mass on the alveolar ridges.

An eruption cyst or ‘eruption hematoma’ is in fact a dentigerous cyst occurring in the soft tissues (Shear, 1992). Whereas the dentigerous cyst develops around the crown of an unerupted tooth lying in the bone, the eruption cyst occurs when a tooth is impeded in its eruption within the soft tissue overlying the bone.