Lec 12 Tooth preparation and crown configuration

Question 1

Is susceptible to frequent periodontal involvement because of the proximity of the divergent distofacial root to the nearby second molar and its inaccessibility to the patient.

a. Maxillary distofacial root
b. Maxillary mesiofacial root
c. Maxillary palatal root
d. Maxillary facial roots

Answer 1

a. Maxillary distofacial root

Question 2

The one that is most frequently removed.

a. Maxillary distofacial root
b. Maxillary mesiofacial root
c. Maxillary palatal root
d. Maxillary facial roots

Answer 2

a. Maxillary distofacial root

Question 3

It is a relatively small root, so the occlusal outline of the resulting preparation commonly resembles a lamb chop when viewed from the occlusal direction.

a. Maxillary distofacial root
b. Maxillary mesiofacial root
c. Maxillary palatal root
d. Maxillary facial roots

Answer 3

a. Maxillary distofacial root

Question 4

Identify the occlusal outline of the ff root preparations:
1. Mx DF root =
2. Mx MF root =
3. Mx P root =
4. Mx F roots =

Answer 4

1. Mx DF root = lamp chop
2. Mx MF root = triangular
3. Mx P root = flat
4. Mx F roots = oval or a circular

Question 5

In the finished restoration, it is important that the contours of the distofacial cusp apical to the contact area have a definite ______ shape. This ensures that crown contours will be aligned with the root configuration in that critical area, preventing __________ on the gingiva.

Answer 5

• concave
• preventing impingement

Question 6

Loss of the ___________ represents a greater loss of support for the remaining tooth.

a. Maxillary distofacial root
b. Maxillary mesiofacial root
c. Maxillary palatal root
d. Maxillary facial roots

Answer 6

b. Maxillary mesiofacial root

Question 7

The ________ embrasure is larger than usual, enabling the patient to keep the area clean.

Answer 7

distofacial

Question 8

The resulting occlusal outline tends to be more triangular in configuration because of the greater faciopalatal dimension of the root that has been removed.

a. Maxillary distofacial root
b. Maxillary mesiofacial root
c. Maxillary palatal root
d. Maxillary facial roots

Answer 8

b. Maxillary mesiofacial root

Question 9

The palatal surface of the preparation will be flat, reflecting the general configuration of the remaining root stump. The tooth preparation will have an abbreviated faciopalatal dimension.

a. Maxillary distofacial root
b. Maxillary mesiofacial root
c. Maxillary palatal root
d. Maxillary facial roots

Answer 9

c. Maxillary palatal root

Question 10

The preparation and resulting restoration usually will have a distinct concave flute on the facial surface arising from the facial bifurcation. Essentially there will be no palatal cusp.

a. Maxillary distofacial root
b. Maxillary mesiofacial root
c. Maxillary palatal root
d. Maxillary facial roots

Answer 10

c. Maxillary palatal root

Question 11

In a maxillary palatal root resection:

The presence of ______ cusps would produce an area inaccessible to hygiene maintenance in the palato- gingival segment of the crown.

It would also create a severe ______ moment on the tooth, which could either tip the tooth palatally or fracture the tooth preparation under the crown.

Answer 11

• palatal
• torquing

Question 12

Preparation of the tooth overlying this root will result in either an oval or a circular configuration depending on the shape of the root itself.

a. Maxillary distofacial root
b. Maxillary mesiofacial root
c. Maxillary palatal root
d. Maxillary facial roots

Answer 12

d. Maxillary facial roots

Question 13

In a ____________ resection, the resulting crown should occlude with its mandibular counterpart in such a way that occlusal forces cannot be directed facially.

a. Maxillary distofacial root
b. Maxillary mesiofacial root
c. Maxillary palatal root
d. Maxillary facial roots

This will place it in a near reverse occlusal, or __________, relationship.

Answer 13

• d. Maxillary facial roots
• crossbite

Question 14

One root is removed while the other remains.

Answer 14

Mandibular hemisection

Question 15

Saving the ______(mesial/distal) segment of the mandibular tooth would be desirable if the molar in question were the last tooth in the arch and the opposing teeth did not extend very far distal to the mandibular first molar.

The _______ root could be used as an abutment for a short-span fixed partial denture replacing the mesial root.

Occasionally the one root may be used as the _____________ for a longer-span fixed partial denture replacing an entire molar. However, this must be viewed as a _________ prosthesis because the remaining distal root has slightly less than one-third of the alveolar support of the intact tooth with normal bone.

Answer 15

• mesial segment
• distal root
• distal abutment; high-risk prosthesis

Question 16

If an effort is made to save both roots of the molar following the resection, the process is described as _______________.

Answer 16

bicuspidization

Question 17

Separation for bicuspidization may be accomplished by moving the roots apart ___________, or it may be accomplished with ___________ on the crown preparations on the separated roots.

Answer 17

orthodontically
interradicular shoulders

Question 18

Separate the roots of a maxillary molar without removing a root.

Answer 18

Skyfurcation

Question 19

Skyfurcation is possible only if the roots are _____, well supported by bone, and distinctly ________.

Answer 19

long;
separate

Question 20

The roots are cut apart and then re-joined by a “crown” that in reality is a very short interradicular splint with concave connectors from one root to the other. The occlusal configuration of the splint is pretty much that of an ordinary molar.

Answer 20

Skyfurcation

Question 21

The roots are cut apart and then re- joined by a “crown” that in reality is a very short interradicu- lar splint with concave connectors from one root to the other. The occlusal configuration of the splint is pretty much that of an ordinary molar.

Question 22

The ___________ procedure, in effect, makes the furcation ______ and moves it occlusally while separating the roots. This improves access to the furcation and protects a caries-prone area.

Answer 22

• Skyfurcation
• metal

Question 23

Success and Failure of Root Resection:
- The failure is more likely to be ______ or ______ than periodontal in nature. This usually means that a root will fracture.
- _________ roots are more likely to fail.
- Successful restoration of periodontally weakened teeth is aided by creating an occlusal scheme with _______________ occlusion, _________ (increased/decreased) vertical overlap, and __________ (flatted/contoured) posterior cusps.

Answer 23

• endodontic; restorative
• mandibular roots
• canine-protected occlusion; decreased overlap; flattened

Question 24

Success and Failure of Root Resection:
- The failure is more likely to be ______ or ______ than periodontal in nature. This usually means that a root will fracture.
- _________ roots are more likely to fail.
- Successful restoration of periodontally weakened teeth is aided by creating an occlusal scheme with _______________ occlusion, _________ (increased/decreased) vertical overlap, and __________ (flatted/contoured) posterior cusps.

Answer 24

• endodontic; restorative
• mandibular roots
• canine-protected occlusion; decreased overlap; flattened