1. Additional retention on abutment is made possible by
A. Increased bulk of gold
B. A full shoulder preparation
C. Proper cementing technique
D. Use of pins, grooves, and box forms
. D. frictional retention can be markedly increased by increasing the surface area of the crown in contact with the tooth surface; this can be accomplished by the use of grooves, pins and box forms.
2. A copper band should be festooned to conform to
A. The gingival margin of the preparation
B. The labial portion of the gingival margin of the preparation only
C. The gingival crest
D. A line one mm. short of the gingival margin of the preparation
A. A copper band should be festooned or trimmed to conform with the gingival margin of the preparation so that when the impression is taken it will not engage an undercut area and be distorted when removed.
3. An effective method for restoring severely broken down vital teeth is
A. Monparallel pin splint
B. Grooves in the cavity preparation
C. The Parapost System
D. Nonparallel pins and alloy
. D. A common method for repairing severely broken down vital teeth is nonparallel pins and alloys, the nonparallel position of the pins plus the grooves hold the alloy much as steel rods reinforce concrete. The Para-Post system is primarily used for endodontically treated teeth and nonparallel pin splint system is used for mobile teeth that are periodontically involved. Grooves in a cavity preparation add additional bulk or material but do not necessarily improve the retention.
4. One of the dangers of using pins in any form is
A. Periodontal penetration
B. Breakage of the pins
C. Tooth discoloration
A. Two of the most common dangers in the use of pins in any form of technique is either pulpal penetration or periodontal membrane penetration. It is desirous to get the pin primarily in dentin and away from the dentino-enamel junction or pulpal tissue.
5. Which of the following pin techniques is the most retentive in restoring severely broken down vital teeth?
A. Cemented
B. Frictional
C. Threaded
D. Post and core
C. Threaded pins are the most retentive because they are self tapping and are retained by the thread. Tensile strength studies have shown that the threaded pins are ten times more retentive than the cemented pins and three times more than frictionally retained pins.
6. The instrument used to make channels in tooth structure is called a
A. Round bur
B. Tap
C. Twistdrill
D. Tapered fissure bur
C. The instrument that is used to make channels for pins in dentin is called a twist drill. Tjis is a relatively new instrument to dentistry, which is primarily and end cutting instrument. The drill has an 8° bite at the tip with two spiral flutes at approximately a 60° angle around the shaft that allows debris to escape from the channel during preparation.
7. A major objective in occlusal treatment for both the natural dentition and the restores dentition in
A. Tripod contacts
B. Axial loading of teeth
C. Tooth to two tooth occlussal
D. Cusp to fossa articulation
E. Proper incisal guidance
. B. This is an objective of occlusal treatment. When treating the natural dentition and performing restorative procedures, occlusal forces should be directed over the long axis of the teeth. Centric contacts on inclines will load the cusps of teeth outside the long axis which can result in irreversiblemobility patterns.
8. Occlusal contacts should be designed so the teeth will
A. Have broad areas of contact]
B. Contact on inclines only
C. Be more likely to contact on inclines
D. Be less likely to contact on inclines
D. Contacts obn inclines and broad contacts cause horizontally directed forces. Horizontal forces can result in occlusal trauma.
9. In lateral motion the teeth on the nonworking or balancing side should
A. Not contact
B. Contact the distal slopes of the upper lingual cusps and the mesial slopes of the lower buccal cusps
C. Contact on the mesial slopes of the upper lingual cusps and the distal slopes of the lower buccal cusps
D. Contact between the lingual grooves and embrasures of the upper teeth and the lower buccal cusp tips
A. The balancing side should immediately disocclude in the lateral bruxing jaw movements. Contacts in lateral motion on the nonworking or balancing side will result in an occlusal interference which can result in mobility, patterns and pain.
10. In lateral movements
A. The cusps should pass between each other on the most horizontal path possible
B. All teeth must contact at the same time
C. Only the molars should contact in lateral excursions
D. Each cusp tip should ride on the highest incline opposite it
A. Cusps that pass through each other in lateral movements on the most horizontal plane possible will result in a maximum of lateral freedom for the neuromuscular system. All else may result in interferences or irritations to the neuromuscular system.
11. Posterior occlusion should result in axial loading of the posterior teeth in the maximum intercuspal position with the anterior teeth
A. End to end
B. In maximum contact
C. Just slightly out of occlusion (about 1 /100 inch)
D. Separated by one mm. or more
. C. Normally shaped anterior teeth cannot be axially loaded and this amount of opening will validate that we are not getting posterior wear.
12. The construction of a fixed bridge from the first or second molar to the lateral incisor is primarily contraindicated because
A. Of their narrow width
B. Of their mobility
C. Of the tearing stress phenomenon
D. None of the above
C. Constructing a fixed bridge from the first or second molar to the lateral would be contraindicated because of tearing stress on the lateral incisor. This is generally a weak tooth and can result in the dislodgement of the bridge and possible displacement of the lateral incisor itself.
13. Which teeth are contraindicated for precision attachments?
A. Molars with furcation involvement
B. Teeth having short coronal extent
C. Teeth having previous restoration
D. Endodontically treated teeth
. B. A tooth must have good coronal length to accept a preceision attachment. Accurate measurement of the attachment and the tooth should be made prior to establishing a treatment plan that would include this modality. If the result of employing a precision attachment would be to alter contour and form and encroach on the pulpal tissue it is contraindicated.
14. Which of the following is the cause for rounded margins in a casting?
A. Too much casting pressure
B. Wax not completely eliminated
C. Overheating the gold
D. Gold in the fluid state
B. Too much casting pressure usually results in the production of fins and is not responsible for rounded margins. Overheating gold or having it in a very fluid state are generally the same and can result in loss of same of the alloys in the gold. Incomplete wax elimination will generally cause rounded margins because marginal areas are obtunded by the material.
15. If the vertical dimension was increased by 1mm. in the first molar region, how many millimeters of increased opening would have been effected in the anterior region?
A. 6 mm.
B. 5 mm.
C. 4 mm.
D. 3 mm.
E. 2 mm.
D. Opening the bite in the posterior by 1mm. will increase this dimension in the anterior by 3 mm. The ratio of opening is a one to three ratio because of angular relation of the mandible to the maxilla.
16. An example of indirect retainer is a
A. Two surface onlay
B. Full crown
C. Precision rest
D. Pin lay
E. Partial veneer crown and its modifications
C. An indirect is a device to assist in fixation of a removable partial denture. It is applied on the side of the fulcrum line opposite to the side to be retained.
17. The infrasurface of a pontic should be
A. Large than the tooth it replaces
B. The same size as the tooth it replaces
C. The same size or slightly smaller depending upon the amount of ridge resorption
D. Approximately five-eights the size of the original tooth it replaces
C. Infrasurface of a pontic should be the same size or slightly smaller depending on the amount of ridge resorption. If the infrasurface of the pontic is made larger than the tooth it replaces, it will obliterate the embrasure spaces. If on the other hand it is made smaller it will foster food impaction and alter the shunting mechanism of food over the occlusal table.
18. Flossing under a ridge lap pontic will
A. Remove plaque
B. Eliminate chronic inflammation
C. Increase the inflammatory response
D. Generally improve the appearance and texture of the ridge
. C. Flossing under a ridge lap pontic will increase the inflammatory response because the dental floss will ride on the extentions of the buccal and lingual aspect of the pontic and will not be able to conform to the contour of ridge tissue. The floss will ride on these two high points and will excoriate the tissue.
19. When the “physiological limit” of tissue is surpassed it will result in
A. Healthy tissue
B. Pathology
C. A condition which is usually reversible
D. A condition which is usually irreversible
B. When the “physiological” tolerance of the tissue is surpassed it will generally result in pathology. This pathological condition will be reversible or irreversible depending upon the extent of tissue damage. The physiological limit of tissue is exceeded if a denture causes local irritation to the mucosa.
20. The buccal-lingual dimension of a pontic should be
A. Large tan the tooth it has replaced
B. Smaller than the tooth it replaces
C. The same size as the tooth it replaces
D. None of the above
C. The buccal dimension of both maxillary and madibular pontics is primarily dictated by esthetics. The lingual dimension of a maxillary pontic is dictated by the fact that the lingual cusps in the Class I occlusion is a secondary holding cusps; therefore, the maxillary buccal lingual dimension should be the same as the tooth it replaces. The buccal extent of the mandibular pontic is dicated not only by esthetics but also it is the primary holding cusps in a Class I occlusion. The lingual dimension of a mandibular pontic is dictated by the tongue and the abutment teeth. The lingual aspect of a mandibular pontic should conform to the abutment teeth in order to preserve the lingual shunting mechanism of food over the occlusal table and be in occlusal harmony with the opening teeth.
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