Restorative dentistry

Question 1

1. What is the file used to explore the apical third of a canal called?
   a. Searcher
   b. Seeker
   c. Finer
   d. Endodontic explorer
   e. Endodontic probe

Answer 1

 B. Seeker

Question 2

2. The file used to explore the apical third of a tooth is usually:
   a. Size 3-5
   b. Size 8-10
   c. Size 15-20
   d. Size 25-30
   e. Size 40-50

Answer 2

 B. Size 8-10

Question 3

3. Which one of the following are you not looking for when you are exploring the apical third of a canal?
   a. Hypercementosis
   b. Branches
   c. Lateral canals
   d. Internal root resorption
   e. Obstruction

Answer 3

 A. Hypercementosis
 Hypercementosis is found on the root surface of a tooth rather than inside the root canal. All the other can be found within the canal.

Question 4

4. The root canal you are working on is curved, and you have pre-curved the file accordingly. How can you best tell the direction the file is pointing within the root?
   a. By mentally noting which direction the file is curved when inserting it
   b. By looking at the position of the number on the side of the file
   c. By cutting a notch on the rubber stop
   d. By taking an intraoral periapical (IOPA) radiograph
   e. By tactile sensation

Answer 4

 D. By cutting a notch on the rubber stop
 By cutting a notch in the rubber stop, you can tell which way the canal is curved. An IOPA is unnecessary for this purpose as it only gives you a two dimensional view of a three-dimensional object.

Question 5

5. If a canal is narrow, which one of the following can be used to make exploration easier?
   a. Water
   b. Bleach
   c. EDTA
   d. Calcium hydroxide
   e. Ferric sulphate

Answer 5

 C. EDTA
 EDTA is a chelating agent which helps open partially sclerosed or narrow canals. Bleach would not help in exploration of the canal, but it would aid in the destruction of bacteria within the canals.

Question 6

6. In a straight-canal tooth, how much should the apical 1mm be prepared to?
   a. The size of the first file which binds in that region.
   b. Two to three sizes larger than the first file which binds within that region.
   c. A size 30 file
   d. A size 40 file
   e. Depends on the tooth

Answer 6

 B. Two to three sizes larger than the first file which binds within that region.
 Ideally the apical 1mm should be prepared to two to three file sizes larger than the first file which binds in that area. This is because the infected dentine in that region needs to be removed enough to clean the area, but without compromising the apical seal.

Question 7

7. In the apical third of a tooth what percentage of canals are curved?
   a. 5%
   b. 30%
   c. 60%
   d. 90%
   e. 100%

Answer 7

 D. 90%
 90% of teeth have some form of curve in the apical third.

Question 8

8. What technique is usually used for the production of an apical flare with hand files?
   a. Crown down
   b. Step down
   c. Tug back
   d. Step back
   e. Step up

Answer 8

 D. Step back
 Step back is the most recognised method of producing an apical flare with hand instruments. Crown down is the accepted method of producing apical flare with rotary instruments. Tug back is the accepted method to find the apex of a tooth using tactile sensation.

Question 9

9. To create an apical flare, larger files are used at decreasing lengths. How much difference should there be between the lengths?
   a. 0.5mm
   b. 1mm
   c. 1.5mm
   d. 2mm
   e. 3mm

Answer 9

 B. 1mm
 This is optimal to produce a good apical flare.

Question 10

10. What is the master apical file?
    a. A file used to measure the length of the root.
    b. A file used to clear debris from the apical region.
    c. The first file which binds at the working length.
    d. The file used to set the final diameter of the apical region preparation.
    e. The file used to remove pulp material from the canal.

Answer 10

 D. The file used to set the final diameter of the apical region preparation.
 A barbed brooch is used to remove pulpal material from the canal. The file used to measure the length of the root is called working length file.

Question 11

11. What is patency filling?
    a. A small file is pushed through the apex to keep it clear of debris.
    b. A small file is used circumferentially on canal walls to prevent lateral canals betting blocked.
    c. A nickel titanium rotary file is used to remove debris from the canal, keeping it clear.
    d. A small file is used with bleach to clean the canal.
    e. A small file is used to open the coronal part of the canal.

Answer 11

 A. A small file is pushed through the apex to keep it clear of debris.

Question 12

12. Which of the following features is the most important in giving a canal resistance form?
    a. Apical stop
    b. Apical seat
    c. Open apex
    d. Natural anatomy
    e. Tapering of canal walls

Answer 12

 E. Tapering of canal walls
 If you taper the canals, it gives them a good resistance form.

Question 13

13. A canal is prepared apically to a size 50 file. No files between size 30 and 50 can pass beyond the length. What type of apical preparation is this?
    a. Apical stop
    b. Apical seat
    c. Open apex
    d. Closed apex
    e. Apical stricture

Answer 13

 A. Apical stop
 This describes the preparation of an apical stop.

Question 14

14. Which one of the following would you not use to make an apical flare?
    a. K-flex
    b. Ni-Ti rotary
    c. GT (Greater Taper)
    d. X-files
    e. Hand files

Answer 14

 D. X-files
 All the others are genuine endodontic files – the x-files are not.

Question 15

15. Which one of the following is not relevant with regard to using rubber dam?
    a. Latex allergy
    b. Sleep apnoea
    c. Claustrophobia
    d. Sinusitis
    e. Emphysema

Answer 15

 B. As rubber dam is made of latex, A) is very important. Also, patients can feel claustrophobic when rubber dam is used. If a patient had sinusitis, they will have difficulty breathing through their nose, and having their mouths covered will be problematic. Patients with emphysema should not have anything impairing their airway, as they struggle for oxygen intake at the best of times.

Question 16

16. Which one of the following is not a function of rubber dam with regard to endodontics?
    a. Decreases salivary contamination
    b. Increases visibility
    c. Contains excess irrigants
    d. Makes pulpal access easier
    e. Decreases medico-legal liability

Answer 16

 D. Makes pulpal access easier.
 Although rubber dam increases visibility, it can sometimes make drilling the access cavity more difficult.

Question 17

17. If you cannot manage to place a rubber dam on a tooth, which one of the following solutions is unacceptable?
    a. Parachute chain
    b. Crown lengthening
    c. No dam
    d. Restore using a copper band
    e. Placing the clamp beaks directly onto the gingivae

Answer 17

 C. No dam
 Parachute chain can be used to secure endodontic instruments to prevent aspiration. Crown lengthening and the use of a copper band can facilitate the placement of the clamp. It is not ideal to place the beaks directly onto the gingivae, although it is done in practice. Placing the beaks on the gingivae can cause trauma which will cause pain to the patient later, and in rare cases may cause permanent damage.

Question 18

18. Which one of the following is not a form of calcium hydroxide?
    a. Life
    b. Dycal
    c. Hypocal
    d. Coltosol
    e. Apexit

Answer 18

 D. Coltosol
 Coltosol is a non-eugenol temporary restorative material. Apexit is an endodontic sealer. Dycal and Life are lining materials which can be used on minimal pulp exposures. Hypocal is non-setting calcium hydroxide.

Question 19

19. Which one of the following statements about root caries is false?
    a. It is more common in patients with reduced salivary flow than in those with normal salivary flow.
    b. It is frequently managed with topical fluoride.
    c. It is frequently managed with systemic fluoride.
    d. It may be managed without a restoration.
    e. It occurs more frequently in males than in females.

Answer 19

 C. It is frequently managed with systemic fluoride.
 Root caries is found more frequently in men than in women, in patients who are elderly and in those who have reduced salivary flow. It can be treated with topical fluoride and restorations or may be monitored if the caries has arrested.

Question 20

20. Which one of the following statements about tooth surface wear is correct?
    a. Attrition is tooth surface wear by non-bacterial chemical dissolution.
    b. Abrasion is tooth wear by other teeth
    c. Attrition is tooth surface wear by surfaces other than teeth.
    d. Erosion is tooth surface wear by non-bacterial chemical dissolution.
    e. Erosion is tooth surface wear by surfaces other than teeth.

Answer 20

 D. Erosion is tooth surface wear by non-bacterial chemical dissolution.
 Abrasion is tooth surface wear by surfaces other than teeth. Attrition is tooth surface wear by other teeth.

Question 21

21. Which one of the following statements about tooth surface loss is correct?
    a. Abrasion is characterised by smooth wear facets.
    b. Erosion is characterised by smooth wear facets.
    c. Abrasion is the commonest type of wear in young patients.
    d. Abfraction is caused by stresses around the cervical margins due to flexure of teeth.
    e. Erosion by gastric acid is usually seen on the labial aspects of upper teeth.

Answer 21

 D. Abfraction is caused by stresses around the cervical margins due to flexure of teeth.
 Attrition is characterised by smooth wear facets. The most common type of tooth wear in the young is erosion due to diet. Erosion by gastric acid is commonly seen on the palatal surfaces of upper anterior teeth, especially in bulimic patients.

Question 22

22. Which one of the following is not a method of monitoring tooth surface loss?
    a. Dietary sheets
    b. Study models
    c. Smith and Knight indices
    d. Laser scanning
    e. Clinical photographs

Answer 22

 A. Dietary sheets
 Dietary sheets are used to find the cause of teeth surface loss, but do not monitor it.

Question 23

23. The desirable degree of taper of a preparation to receive a cast restoration is:
    a. Lees than 2*
    b. 2-4*
    c. 5-7*
    d. 8-12*
    e. Greater than 12 *

Answer 23

 C. 5-7*
 The closer to parallel the walls of the preparation, the greater the resistance to placement. However, a taper of 5-7* is acceptable.

Question 24

24. Which one of the following statements is true?
    a. Enamel contains 92% hydroxyapatite by weight.
    b. Enamel is thinnest where it overlies the cusps.
    c. Diamond burs removal enamel by fracturing it.
    d. Tungsten carbide burs remove enamel by grinding.
    e. Stresses within a cavity preparation can be minimised by rounding the internal angle lines.

Answer 24

 E. Stresses within a cavity preparation can be minimised by rounding the internal angle lines.
 Enamel is 97% hydroxyapatite by weight. Diamond burs grind away enamel and tungsten carbide burs fracture enamel. Enamel is thickest over the cusps.

Question 25

25. Which one of the following statements regarding surgical endodontics is true? a. It is indicated for all failed root canal treatments. b. It is not indicated for patients who have pulp stones. c. It is indicated to prevent removal of extensive coronal restorative work. d. It is indicated in the presence of a periapical radiolucency. e. It is contraindicated in multirooted teeth.

Answer 25

 C. It is indicated to prevent removal of extensive coronal restorative work.  Apicectomy can be performed in teeth with extensive coronal restoration work and pulp stones and can be performed in multirooted teeth. However, the percentage of success dramatically decreases in these teeth.

Question 26

26. Which one of the following problems occurs because of a reduced vertical dimension? a. Difficulty with ‘S’ sounds. b. Poor appearance, showing far too much teeth. c. Clicking of teeth when talking d. Sunken lower face, elderly looking appearance. e. Poorly localised pain in the lower denture bearing area that is relieved when the denture is removed.

Answer 26

 D. Sunken lower face, elderly looking appearance.

Question 27

27. Which one of the following statements regarding overdentures is incorrect? a. They are contraindicated in patients with cleft palates. b. They are contraindicated in patients with inadequate interarch space. c. They are contraindicated in patients with uncontrolled periodontal disease. d. They may be indicated when converting a partially dentate patient into a complete denture wearer. e. They may be indicated in patients with attrition.

Answer 27

 A. They are contraindicated in patients with cleft palates.  The contraindication for overdentures are poor oral hygiene, rampant caries and uncontrolled periodontal disease.

Question 28

28. Which one of the following statements regarding Kennedy’s classification for partially edentulous arches is correct? a. A patient with upper right 876543 and an edentulous upper left region would be described as a Kennedy Class IV. b. A patient with lower right 543 and lower left 543 would be classified as Kennedy Class IV. c. A patient with lower right 76 21 and lower left 123 567 would be classified as Kennedy Class II. d. A patient with lower right 76 21 and lower left 123 567 would be classified as a Kennedy Class III modification 1. e. A patient with lower right 87654321 and lower left 123 would be described as Kennedy Class III.

Answer 28

 D. A patient with lower right 76 21 and lower left 123 567 would be classified as a Kennedy Class III modification 1.  Kennedy Class I = bilateral free end saddle.  Kennedy Class II = unilateral free end saddle.  Kennedy Class III = unilateral bounded saddle.  Kennedy Class IV = a single bounded saddle anterior to the abutment teeth.  A modification of other additional edentulous area can be added to Classes I-III when there are other missing teeth.

Question 29

29. Which one of the following statements regarding surveying of casts for denture design is correct? a. It is carried out for complete and partial dentures. b. It is carried out for complete dentures. c. It can determine the occluso-vertical dimension. d. It can be used to determine undercuts with regard to the path of insertion of a denture. e. It is always carried out with the model at right angles to the analyser rod.

Answer 29

 D. It can be used to determine undercuts with regard to the path of insertion of a denture.  Surveying is only carried out for partial dentures, and is used to determine a path of insertion and guide-planes.

Question 30

30. Which one of the following statements regarding partial denture clasps is true? a. In order to be functional they must be resisted by a non-retentive clasp arm. b. Cast cobalt-chrome clasps need to engage undercuts of greater than 0.5mm. c. Stainless steel clasps are more flexible than gold clasps. d. The longer the clasp, the less flexible it will be. e. Gingivally approaching clasps are more conspicuous than occlusally approaching clasps.

Answer 30

 A. In order to be functional they must be resisted by a non-retentive clasp arm.  Cast cobalt-chrome clasps need to engage undercuts of less than 0.25mm. Gold is more flexible than stainless steel, and the greater the length of clasp, the greater the flexibility.

Question 31

31. Which one of the following is not an advantage of having an overdenture rather than a complete denture? a. Better aesthetics b. Preservation of alveolar bone c. Better sensory feedback d. Increased biting forces e. More reproducible retruded jaw relations.

Answer 31

 A. Better aesthetics.  Complete dentures and over-dentures have the same aesthetic appeal. By retaining roots, the alveolar bone is retained and there is increased proprioception. By having greater retention from the abutments, the patient is able to produce increased biting forces compared with the complete denture wearer.

Question 32

32. The depth of reduction of the marginal ridge for an occlusal rest seat in a removable partial denture construction is: a. 0.5mm b. 1.5mm c. 3.0mm d. 5.0mm e. None of the above

Answer 32

 B. 1.5mm  The most optimal rest seat reduction is 1.5mm. If less reduction is performed, then the rest seat will struggle to retain. If there is greater reduction then the tooth structure may be compromised.

Question 33

33. Cross-arch stabilisation is the main function of which one of the following parts of a removable partial denture? a. Major connector b. Minor connector c. Bracing arm d. Rest seat e. Indirect retainer

Answer 33

 A. Major connector  Major connector = part that connects the prosthetic teeth together.  Minor connector = small struts protruding from the lingual bar at roughly 90 degree angles.  Direct retainer = the clasp arms act to hug the teeth and keep the RPD in place.  Indirect retainer = the physical retainer is a mesh of metal that allows the pink base material to connect to the metal framework of the RPD. Some consider physical retainers a component in their own category, whereas others consider them within the indirect retainer category (thus making a total of six components).  Base is the pink material, mimicking gingivae.  Teeth – plastic or porcelain formed in the shape of teeth.

Question 34

34. All clasps assemblies should not have: a. One area of retention b. Two areas of retention c. A guide plane d. A bracing element e. Rest seat

Answer 34

 B. Two area of retention  Direct retainers come in various designs: o Cast circumferential clasp (suprabulge):  Akers’  Half and half  Back-action  Ring clasp o Wrought wire clasp o Roach clasp (infra-bulge):  I-bar  T-bar  Y-bar  7-bar  Both cast circumferential and wrought wire clasps are suprabulge clasps, in that they engage an undercut on the tooth by originating coronal to the height of contour, while Roach clasps are infrabulge clasps and engage undercuts by approaching from the gingivae.

Question 35

35. A denture which has bilateral free-end partially edentulous saddles is classified as: a. Kennedy Class I b. Kennedy Class II c. Kennedy Class III d. Kennedy Class IV e. Kennedy Class V

Answer 35

 A. Kennedy Class I  Kennedy class I and II RPDs are both tooth-and-tissue-borne (meaning they both clasp onto teeth as well as rest on the posterior edentulous area for support).  Class III RPDs are strictly tooth-borne, which means they only clasp onto teeth and do not need to rest on the tissue for added support.

Question 36

36. Fill in the gap in the following statement: any clasp assembly must satisfy the basic principle of clasp design that the tooth must be encircles by that clasp by a minimum of … degrees of the greater circumference of the crown of the tooth passing from diverging axial surfaces to the converging axial surface. a. 80 b. 160 c. 180 d. 270 e. 300

Answer 36

 C. 180  A clasp must encircle the tooth by a minimum of 180 degrees to provide adequate retention.

Question 37

37. A rest for a removable partial denture must be designed to: a. Transmit force horizontally on an abutment. b. Transmit force along the long axis of the tooth. c. Prevent the clasp slipping cervically on a tooth. d. Answer A and C. e. Answer B and C.

Answer 37

 E. Answer B and C.  Rest seats are designed to transmit the force along the long axis of the tooth and also to prevent the clasp slipping cervically on a tooth.