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Pre-Clinic > class IV preparation > Flashcards

class IV preparation Flashcards

1
Q

class IV lesion

A

a proximal lesion of anterior teeth that involves one or more incisal angles

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2
Q

what can cause a class IV lesion?

A
  • caries
  • trauma
  • occlusal interferences
  • grinding
  • or any combo of the above
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3
Q

type of preparation and restoration can vary based on the:

A
  • cause
  • esthetics
  • occlusal scheme
  • finances
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4
Q

when should you check the occlusion of a class IV?

A

BEFORE preparation

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5
Q

when should you choose a composite body shade?

A
  • prior to beginning
  • in proper light
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6
Q

classifications of fractures of a class IV

A
  • Ellis Classifications: bases on extent of fracture
  • Class I
  • Class II
  • Class III
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7
Q

class I fracture of a class IV prep

A
  • in enamel only
  • best pulpal prognosis
  • retention can be challenging due to occlusion
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8
Q

class II fracture of a class IV prep

A
  • fracture extends through enamel into dentin
  • risk of pulpal involvement long term increases (due to original trauma)
  • can be restored with direct composite, veneers, or crowns
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9
Q

class III fracture of a class IV prep

A
  • extends through enamel and dentin and exposed pulpal tissue clinically
  • minimally requires pulpal protection prior to retoration
  • need for root canal increases
  • long term, may require crown
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10
Q

other classifications according to trauma (non class IV lesion)

A
  1. non vital tooth without loss of tooth structure
  2. total tooth loss (avulsion)
  3. displacement of tooth without fracture of crown or root
  4. fracture of entire crown
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11
Q

before treatment with trauma:

A
  • must evaluate for other injuries (lacerations, head injury, jaw fractures, etc.)
  • must evaluate tooth for vitality (if vital = re-test vitality as it may become non-vital)
  • radiographic exam (!!! - look for widened PDL, caries, root fractures)
  • discuss options with patient
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12
Q

before class IV treatment consider:

A
  • consider nature of injury
  • need for root canal now or in future
  • prep design
  • restorative material
  • patient occlusion!!!!
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13
Q

complications

A
  • retention?
  • root canal?
  • post and core?
  • crown?
  • veneer?
  • patient’s bite
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14
Q

bite classification

A

class I: normal
class II: overbite
class III: underbite
open bite

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15
Q

complications with bite:

A
  • laterotrusive or protrusive interferences
  • severely worn dentition (bruxism)
  • collapsed bite
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16
Q

considerations (of variation)

A
  • “young” tooth will have a large pulp chamber and high pulp horns
  • tooth’s apex may not be closed and will require treatment prior to root canal
  • consider pulpal protection even in a moderate fracture (CaOH as liner, glass ionomer as a base)
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17
Q

what must you recognize in a class IV:

A
  • signs of pulpal injury from trauma
  • receded pulp
  • widened PDL and Periapical periodontitis
  • may require root canal
  • tooth may present with a darkened color
18
Q

Class IV preparation of a #8 composite

A
  • shaped according to extent of fracture
  • retention is placed internally in the dentin area, and the entire external cavosurface margin has a continuous bevel
19
Q

outline form for class IV fracture (MIFL) of tooth #8

A
20
Q

how to create the fracture

A

remove the blackened area (as seen in outline form) with a tapered diamond rotary instrument

21
Q

class IV preparation after creating the fracture:

A
  • remove tooth from typodont
  • draw the area of the dentin with a pencil
  • replace tooth into typodont
  • place rubber dam
22
Q

after drawing on the dentin and placing the rubber dam:

A
  • use 35 carbide bur
  • remove dentin to a depth of 1mm
  • measure depth with perio probe
23
Q

after drilling into dentin:

A

use hand instruments (hatchet and hoe) to smooth the axial wall of prepared dentin

24
Q

after smoothin with hatchet/hoe to smooth dentin:

A
  • use 1/2 round bur
  • place retention at axio-gingival line angle and at axio-incisal point angle
25
Q

after placing retention:

A
  • use tapered diamond rotary instrument
  • begin beveling on the external facial surface
26
Q

the bevel being placed should be:

A
  • 1mm wide around the entire cavosurface margin except for GINGIVAL
    (incisal, lingual, facial)
27
Q

class IV finished prep criteria

A
  1. follows outline form of the fracture
  2. 1/2mm into dentin
  3. smooth internal surfaces
  4. retention at the axio-gingivial line angle and at the axio-incisal point angle
  5. 1mm bevel around the facial, lingual, and incisal margins
28
Q

Class IV composite restoration (only for preclinic purposes - no acid etching):

A
  • use bonding agent and apply small amount for 20 seconds
  • air thin
  • cure for 20 seconds
  • place mylar strip interproximally and place wedge to hold
29
Q

construction of the lingual matrix is made with what material?

A

polyvinyl siloxane putty

30
Q

what can the lingual matrix be constructed from?

A
  • a waxed up model of the desired final contour of the restoration
  • a properly contoured existing restoration that needs to be replaced
31
Q

how is the polyvinyl siloxane putty used?

A
  • should cover lingual surface of the tooth to be restored
  • preferably includes at least one tooth adjacent on each side
  • putty should extend to gingival portion and cover incisal edge (end @ facio-incisal line angle)
32
Q

what does the lingual matrix correctly reproduce?

A
  • contour of the lingual surface
  • embrasures
  • marginal ridges
  • helps confine material to restored area
33
Q

what does the lingual matrix NOT provide?

A
  • proximal contact
  • proximal contour
  • seal the gingival margin
34
Q

application of composite onto prep:

A
  1. choose capsule
  2. place small amount into retentive areas (WHILE holding matrix against facial surface)
  3. light cure
  4. continue adding in increments no more than 2mm
  5. fold matrix over facial and lingual surfaces of tooth for proper contour
  6. light cure through matrix
  7. repeat until slightly overbuilt (for polishing)
  8. polish
35
Q

what is the oxygen inhibition layer?

A
  • occurs when light cured
  • oxygen in the air interferes with polymerization
  • located on surface of composite
  • this layer is removed during finishing and polishing
36
Q

the anatomical contours must _________ the contralateral tooth.

A

MIRROR

37
Q

what burs do you use for contouring the facial and incisal surfaces?

A

tapered diamonds

38
Q

what burs do you use for contouring the lingual cavity?

A

football shaped diamond

39
Q

why is anatomy important?

A
  • esthetics
  • function
  • preventing future fractures
  • occlusion
40
Q

final restoration must be checked for:

A

interferences in MIP, protrusion, and lateral excursion

41
Q

polishing:

A
  1. soflex discs (coarse to very fine = dark to light)
  2. wipe off restoration with gauze between disc changes
  3. flame shape/point rubber abrasive for lingual cavity
  4. enhance bur on slow speed to pre-polish lingual fossa and MR area
  5. abrasive strip for interproximal surface (coarse to fine)
  6. luminescence
42
Q

finished restoration criteria

A
  1. smooth and shiny
  2. no pits or scratches
  3. natural contour that mirrors contralateral tooth
  4. no excess composite
  5. natural shape (embrasures)
  6. no ditching
  7. strong interproximal contacts

Pre-Clinic (4 decks)

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