Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Prostho 3 > 9. Fixed dental bridges > Flashcards

9. Fixed dental bridges Flashcards

1
Q

What is a pontic?

A

A missing tooth restored by a structure

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What is a bridge?

A

FPD that replaces missing teeth

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Advantages of bridges? (5)

A
  • Firm Attach.
  • Esthetics.
  • Comfort for the patient.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Why is a bridge better than an RPD?

A
  • hygiene

- better load transfer to abutment teeth

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What are the different types of bridges? (6)

A
  • Fixed
  • Cantilever
  • maryland
  • with interlocks
  • removeable
  • with hygienic pontics
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Fixed bridge characteristics? (3)

A
  • Most common type of bridge.
  • Retainers are cemented onto the abutment teeth.
  • Rigid connectors
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Cantilever bridge characteristics? (5)

A
  • The pontic has a connector and a retainer only on one side.
  • Less use due to the implants rehabilitation.
  • Occlusal overload of the abutment teeth.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Cantilever bridges need to be careful with… (2)

A
  • Occlusion

- periodontal attachment

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What law is important to think about for cantilever bridges?

A

Ante’s

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What is ante’s law for bridges?

A

The total root surface/periodontal membrane area of abutment teeth must be equal to or exceed the total root surface area of the teeth being replaced

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What missing teeth can we use cantilever bridges for? (3)

A
  • upper lateral incisors
  • First premolars
  • First molars
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

How do we use a cantilever bridge for upper lateral incisors? (2)

A
  • abutment: canine and first premolar

* watch for crown-to-root ratio and eccentric movements

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

How do we use a cantilever bridge for first premolars?

A

Abutment: 2nd premolar and 1st molar

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

How do we use a cantilever bridge for first molars?

A
  • Abutment: 1st and 2nd premolar

- short pontic: 1/2 MD distance from 1st to 2nd premolar

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Characterisitcs of maryland bridges? (4)

A

• Metal or ceramic “wings” over abutment teeth.
• Cemented with resin cements.
• Rely on adhesion to stay in place.
• Very small preparation on the lingual surface of abutment teeth
(over enamel).

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Indications for maryland bridges? (3)

A

Provisional restorations

  • during implant healing
  • young patients
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Bridges with interlocks characteristics? (5)

A
  • Cannot be removed. It is fixed.
  • Non-rigid connector
  • Used as broken-stress mechanical union
  • Two parts joined by an attachment (interlock)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Indications of bridges with interlocks?

A

Situations of long bridges or edentulous pieces

on both sides of a tooth

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What are the parts of a bridge with interlocks? (3)

A
  • Patrix and matrix joined by an attachment (interlock)
  • Patrix should be at the mesial surface of the pontic.
  • Matrix should be at the distal surface of the retainer.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What is a frequent complication of bridges with interlocks ?

A
  • intrusion of one of the parts,

- usually the matrix

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Where are bridges with interlocks placed? (2)

A
  • Placed in the middle abutment.

* If placed in the terminal ones—pontic acts as lever arm

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Where does the female go in a bridge with interlocks?

A

On the distal surface of the retainer cemented to the abutment

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Where does the male go in a bridge with interlocks?

A

Mesial surface fo the pontic

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

Bridges with interlocks: movement? (3)

A
  • Movement will seat the key into the keyway
  • vertical forces = mesial movements
  • placed mesially, the movement can unseat the key
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

Vertical forces and bridges with interlocks?

A

Mesial direction of movements

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

Indication of bridges with interlocks?

A

Unparalleled abutment teeth

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

Bridges with interlocks are rarely used because..

A

of the intrusion produced

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

How do you combat the intrusion produced with bridges with interlocks?

A

non-rigid connector is placed over the pm to not

increase the tilting of the molar

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

Removable bridge characteristics? (2)

A
  • Large ridge defects

* Friction retention.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

Retentive devices for removable bridges?

A
  • bar

- telescopic crowns

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

When do we use telescopic crowns?

A
  • removable bridges

- for badly aligned abutment teeth

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

What are the parts of a telescopic crowns of removable bridges?

A
  • primary coping

- secondary coping

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

Characteristics of telescopic crowns primary copings for removable bridges? (3)

A

◦ Cemented to the abutment teeth.
◦ 3-6º taper.
◦ Adequate height.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

Characteristics of telescopic crowns secondary copings for removable bridges? (2)

A

◦ Are joined to the removable part.

◦ Not cemented to the primary copings.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

Characteristics of low resistance all-ceramic bridges? (4)

A 
• Feldspathic
• Aesthetics
• Veneering
layers
• 70-90Mpa
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

Characteristics of moderate resistance all-ceramic bridges? (3)

A

• Lithium Disilicate
• Monolithic or with veneered
layers over core
• 360-400Mpa

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
37
Q

Characteristics of moderate resistance all-ceramic bridges? (3)

A

• Zirconia
• Monolithic or with veneered
layers over core
• 900Mpa

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
38
Q

The higher the resistance of all ceramic bridges, the…

A

less translucency

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
39
Q

LDS bridges can only be used.. (3)

A
  • for anterior bridges
  • max 3 pieces
  • last abutment = 2nd premolar
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
40
Q

LDS aesthetic vs resistance?

A

Higher esthetics than resistance

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
41
Q

Which LDS should we use for bridges? (2)

A
  • monolithic (higher survival rate)

- better is pressed

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
42
Q

do LDS bridges need connectors?

A

Thick connectors : 16mm2 (4x4)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
43
Q

Zirconia bridges characteristics? (2)

A
  • high resistance

- less aesthetic

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
44
Q

Zirconia new options for bridges?

A
  • against chipping

- with high aesthetic

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
45
Q

Zirconia bridges connector?

A

Thicker than metal

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
46
Q

What was the old zirconia bridge option?

A
  • Zirconia core + aesthetic veneer

- high risk of chipping (main failure reason)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
47
Q

What was the new zirconia bridge option? (5)

A
  • Monolithic
  • No chipping
  • solidity
  • strength
  • suited for bruxists
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
48
Q

What are the masticatory forces a material must support without fracturing over molars?

A

300-800N

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
49
Q

What are the masticatory forces a material must support without fracturing over anterior sectors?

A

60-200N

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
50
Q

What are the masticatory forces a material must support without fracturing for parafunction?

A

1000N

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
51
Q

What are the masticatory forces zirconia supports?

A

900-1200N

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
52
Q

What are the masticatory forces pressed LDS supports?

A

400N

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
53
Q

What are the masticatory forces milled LDS supports?

A

360N

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
54
Q

Indications for zirconia bridges?

A
  • teeth and implants
  • posterior (better when monolithic)
  • unitary crowns
  • bruxists (monolithic)
  • discolored or ETT
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
55
Q

Where should zirconia bridges not be used? (2)

A
  • Anteriorly

- b/c High opacity

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
56
Q

What different zirconia’s can be used in a bridge? (3)

A
  • Monolithic
  • HT Zr
  • Layered Zr core
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
57
Q

Why do we use monolithic zirconia in bridges? (3)

A
  • strong and resistant
  • full contour crowns
  • FC bridges
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
58
Q

Why do we use HT zirconia in bridges? (2)

A
  • high translucent

- good aesthetics for anterior sector

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
59
Q

Characteristics of layered zirconia in bridges? (2)

A
  • with feldspathic veneer

- Not ideal for posterior sector

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
60
Q

Strength of monolithic zirconia bridges?

A

High

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
61
Q

monolithic zirconia bridges biocompatibility?

A

Less risk of allergies (Ni, Pd)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
62
Q

monolithic zirconia bridges marginal fit?

A

Good and accurate

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
63
Q

monolithic zirconia bridges hypersensitivity? (2)

A
  • Reduces hypersenstivity

- resistant to temperature changes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
64
Q

Monolithic zirconia bridges X-rays?

A

Radiopacity

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
65
Q

Monolithic zirconia bridges corrosion?

A

No corrosion

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
66
Q

Monolithic zirconia bridges clinical longevity?

A

Good

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
67
Q

Monolithic zirconia bridges preparation?

A

Less tooth prep is required

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
68
Q

Monolithic zirconia bridges aesthetics compared to PFM?

A

Mono Zr better aesthetics

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
69
Q

Monolithic zirconia bridges vs LDS?

A

LDS better aesthetics

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
70
Q

Monolithic zirconia bridges and dark substrate colors?

A

Can mask them

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
71
Q

Monolithic zirconia bridges prothetic space?

A

Less prosthetic space needed

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
72
Q

Monolithic zirconia bridges abrasiveness?

A

Not very abrasive when polished correctly

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
73
Q

Monolithic zirconia bridges working time?

A

Reduction of working time

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
74
Q

Zirconia bridge connectors? (3)

A
  • require a min volume as they fracture often
  • Dimensions are directly related to flexural resistance and resistance to fracture
  • require more volume than PFM bridges
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
75
Q

Zirconia bridge connector dimensions? (3)

A

Abutment- Pontic:

  • 7mm2 for anterior bridges
  • 9mm2 for posterior bridges

Bridges with more than 1 pontic: 12mm2

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
76
Q

Zirconia bridge finish line? (3)

A
  • Finish line: rounded shoulder or chamfer
  • Finish Line of 0,8 to 1,2 mm
  • Monolithic FL: 0,5mm
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
77
Q

Zirconia bridge occlusal reduction?

A

0.6-1.5mm

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
78
Q

Posterior bridge connectors for zirconia?

A

9mm2

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
79
Q

Anterior bridge connectors for zirconia?

A

7mm2

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
80
Q

Size of bridge connectors for zirconia between pontics?

A

12mm2

- subject to higher loads and stress

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
81
Q

Ridge lap pontic characteristics? (4)

A
  • Concave shape, surround the ridge buccally and
    lingually/palatal
  • Intimate adaptation to the gingiva
  • Produces inflammation and possible bone resorption
  • Not recommended
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
82
Q

Ridgelap pontic aesthetics and hygiene? (2)

A
  • Difficult hygiene

- Very aesthetic

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
83
Q

Conical pontic aesthetics and hygiene? (2)

A
  • very hygienic

- poor asethtic

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
84
Q

Conical pontic characterisitcs?

A
  • One contact point with gingiva

- convex shape MD and BL

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
85
Q

Conical pontic cons? (2)

A
  • Not very comfortable

- not to be used on upper law, creates phonetic problems

86
Q

Where are conical pontics indicated?

A

Posterior areas over thin ridges

87
Q

Where does a modifed ridge lap pontic go?

A
  • extends over buccal surface
  • doesn’t surpass bone ridge lingually
  • contacts gingiva slightly over the ridge
88
Q

Pro’s of modified ridge lap pontic?

A
  • Good hygiene

- Good aesthetic (design creates illusion of real tooth)

89
Q

Ovoid pontic bridge characteristics?

A
  • Pontic goes into the concavity created in the gingiva
  • most aesthetic
  • preserve interdental papilla or creates it
  • moderately easy to clean
90
Q

Where do you use an ovoid pontic?

A

Only anterior sector with high esthetic needs

91
Q

Ovoid pontic steps? (3)

A
  • First shaped with provisional right after the extraction
  1. concavity created with rounded bur
  2. provisional placed so tissues heal with the shape
92
Q

What is important for ovoid pontic success?

A

Provisionalization step

93
Q

Hygienic pontic location?

A
  • separated from the ridge

- atleast 3mm gap, minimum 1mm from edentulous ridge

94
Q

What volume is needed for a hygienic pontic?

A

3mm at least

95
Q

Con’s of the hygienic pontic?

A
  • Zero aesthetic
  • not comfortable
  • rigid alloy
96
Q

Indications of the hygienic pontic? (3)

A
  • Periodontitis with poor oral hygiene.
  • Handicapped patients.
  • Epilepsy: gingival hypertrophy.
97
Q

Bridge connector rigidity depends on…? (3)

A

Adequate diameter minimums:

  • Metal: 4mm2 (2x2)
  • High strength ceramic: 16mm2 (4x4)
98
Q

Bridge connector shape resistance?

A
  • Triangular = more resistant where the vertical axis is the bigger one
99
Q

Connector width? (2)

A
  • 1/3 to 2/4 of the B-P diameter

- Also depends on the length and alloy material

100
Q

Connector height ? (2)

A
  • Far from the papilla’s to create embrasures for the hygiene
  • Joins at the medium third, slightly below the fossae of the retainers
101
Q

Depending on the connector, we can classify the bridge as…

A
  • Fixed-fixed

- Fixed-removeable (combined)

102
Q

What is a fixed-fixed bridge?

A
  • Classical: rigid connectors, cemented
  • Cantilevler (in extension)
  • fixed removable: cemented retainers, removable structure on top over telescopic crowns or a bar
  • Adhesives (maryland)
  • Hygienic
103
Q

What are the different retainers for bridges?

A
  • intracoronal

- extracoronal

104
Q

What is an intracoronal retainer for bridge?

105
Q

What is an extracoronal retainer for a bridge?

A

Full coverage crown

106
Q

Extracoronal bridge retainer characteristics?

A
  • Provide better protection to abutment teeth
  • 3/4 crowns
  • reverse 3/4 crowns
  • 7/8 crown
107
Q

What are the different steps of bridge treatment planning? (5)

A
  1. Assessment of abutment teeth
  2. Assessment of edentulous spaces
  3. Biomechanical considerations
  4. information to the patient
  5. possible options based on what teeth are missing
108
Q

Bridge treatment planning: what do we assess on the articulator? (4)

A
  • Prosthetic space
  • Mesialisations
  • Occlusion
  • Lateral guidance
109
Q

What factors do we consider when assessing abutment teeth? (4)

A
  • Pulp vitality
  • Condition of clinical crown
  • periodontal condition
  • root condition
110
Q

What is the optimal situation for an abutment tooth’s pulp vitality?

A

Vital tooth without caries or restorations

111
Q

Bridges: If an abutment tooth has endodontic treatment… (3)

A
  • Can be used for FPD
  • Ferrule effect is important
  • bridges fail 2x more than in a vital tooth
112
Q

Does every abutment tooth in a bridge need endo treatment?

113
Q

When is an endo treatment indicated in an abutment tooth for a bridge? (3)

A
  • If preparations will need to go into the pulp
  • accidental pulp exposure
  • irreversible pulpitis symptoms after preps
114
Q

Ideally, the condition of the clinical crown of an abutment for a bridge should …

A

Have no caries, abfractions, erosions, abrasions or restorations

115
Q

If the abutment to a bridge has a survey line under the gingiva, what should we do? (3)

A
  • Consider crown lengthening
  • bad situation
  • ex. gingival hyperplasia
116
Q

The clinical crown of an abutment for a bridge should not be…

117
Q

The size of clinical crown of an abutment for a bridge? (3)

A
  • Ideally A bigger or equal to B
  • Too short clinical crowns will provide very little retention.
  • The bigger the crown the better the retention
118
Q

The position of clinical crown of an abutment for a bridge? (3)

A
  • Ideally no incline and no
    rotation.
  • Straight abutments = good path of insertion
  • Tooth preparation can correct inclination to a certain degree.
119
Q

Whats the relationship between the clinical and anatomical crown of an abutment for a bridge? (2)

A
  • usually the clinical crown is shorter

- enamel below the gingiva

120
Q

When can a clinical crown be longer than the anatomic crown? (2)

A
  • over erupted tooth

- gingival recession

121
Q

How do you prepare an abutment for a bridge if the clinical crown is longer than the anatomic crown? (3)

A

◦ Supragingival finish line if possible.
◦ Metal collar (when esthetics are not critical).
◦ At esthetic areas: over cementum (try to achieve maximum fit).

122
Q

What are the periodontal conditions allowed for an abutment tooth? (5)

A
  • No gingivitis
  • no more than 3mm probing depth
  • at least 2mm of attached gingiva
  • no furcation defects
  • no mobility
123
Q

If periodontal treatment has to be preformed on an abutment, what are the guidlines?

A

Wait atleast 2 months to get stable gingival level after root scaling

124
Q

Abutments and larger teeth?

A

Greater surface area = better ability to support forces

125
Q

Ante’s law for a missing first molar?

A

Surface of the 2nd premolar and 2nd molar is bigger => GOOD PROGNOSIS

126
Q

Ante’s law for a missing first premolar and first molar?

A

surface of the retainers and pontics are equal

127
Q

Ante’s law for missing premolars and first molar?

A
  • missing teeth surpass surface of retainers
  • Bad prognosis
  • should not use a bridge here
128
Q

What do we look for radiographically when assessing an abutments periodontal health? (4)

A
  • Even periodontal ligament
  • No bone resorption
  • small horizontal bone loss can be acceptable
  • no occlusal trauma signs
129
Q

Radiological assessment of an abutment tooth should yield images with… (4)

A
  • Adequate crown-to-root ratio.
  • No periapical radiolucencies.
  • No root resorptions.
  • No cementomas or hypercementosis.
130
Q

How do we assess the crown to root ratio of an abutment?

A
  • radiographically

- measure from bone crest level

131
Q

What is the ideal crown:root for abutment teeth?

132
Q

What is the minimum acceptable crown to root ratio for an abutment?

133
Q

Assesment of abutment teeth: the crown to root ratio has to be considered with… (3)

A
  • Antagonist arch (CD, FD…).
  • Periodontal condition of the antagonist arch.
  • Length of the edentulous space.
134
Q

Abutments and single rooted teeth? (3)

A

◦ Oval section ones are better than round section roots .
◦ E.g: upper lateral incisors are not good teeth.
◦ Better if they are slightly curved.

135
Q

Abutments and multirooted teeth? (3)

A

◦ Better behavior and retention
◦ Divergent roots are better than fused ones
◦ Better periodontal support

136
Q

Root surfaces can be diminished due to.. (2)

A

◦ Root resorption because of orthodontic treatment.

◦ Periodontal disease.

137
Q

What do we look at when assessing edentulous spaces?

A
  • length
  • shape of the space
  • shape of edentulous gap
  • location of the space
  • prosthetic space
138
Q

Assement of the edentulous space will determine… (3)

A
  • Number of abutment teeth used
  • Type of pontic
  • Bridge biomechanics
139
Q

What affects bridge biomechanics? (3)

A
  • Alloy used
  • Thickness of the pontics
  • Type of connector
140
Q

Whats the relationship between load and length of edentulous space?

A

Longer space = greater the load

141
Q

What is the prognosis of a bridge if 1 tooth is missing?

A

Very good prognosis

142
Q

What is the prognosis of a bridge if 2 teeth are missing?

A

Good prognosis

143
Q

What is the prognosis of a bridge if 3 teeth are missing?

A

Unfavorable prognosis

144
Q

What is the prognosis of a bridge if 4 teeth are missing? (3)

A

Not indicated

Use implants or RPD

*exception: lower incisors

145
Q

What causes failure of long bridges?

A
  • Periodontal ligament overload.
  • Failure of the materials.
  • Misfit at distal margins.
  • Biomechanical failure ( excess of lever or torque)
146
Q

What is the prognosis of a bridge if the edentulous space is straight?

A

More favorable

147
Q

What is the prognosis of a bridge if the edentulous space is curved? (3)

A

More unfavorable

  • ex. upper front teeth
  • may require using more teeth in the bridge
148
Q

What type of pontic do you use if the edentulous ridge is normal (2)

A
  • Modified ridge lap

- Conical

149
Q

What is a normal edentulous ridge?

A

Convex and no alot of bone loss

150
Q

What type of pontic do you use if the edentulous ridge is thin but still convex?

151
Q

What type of pontic do you use if the edentulous ridge is flat and wide?

A
  • oval pontic (higher estheics)

- Can be done with provisionals or surgically

152
Q

What type of pontic do you use if the edentulous ridge has defects?

A

May need surgery to modify it

153
Q

What is siberts class I

A

Class I: horizontal, width loss

154
Q

What is siberts class II

A

vertical, height loss

155
Q

What is siberts class III

A

Combination

156
Q

If the edentulous area is maxillary, the occlusal load will…

A

tend to spread abutment teeth

157
Q

If the edentulous area is mandibular, the occlusal load will…

A

tend to gather abutment teeth

158
Q

What is more favorable, a maxillary or mandibular abutment space? (2)

A

Mandibular

- better bone quality and better support

159
Q

Edentulous space vs prosthetic space? (4)

A
  • sometimes the edentulous space will be invaded
  • extrusion on the antagonist
  • mesial migration of the adjacent
  • some previous treatment might be needed
160
Q

How does the occlusal load affect a bridge?

A

WIll bend the bridge towards the ridge

161
Q

What happens if the bridge bends towards the ridge? (3)

A
  • tension over retainers => torque over abutments
  • tends to separate retainer and abutment
  • lever effect on curved edentulous spaces - can luxate teeth
162
Q

Occlusal forces over a bridge can cause: (4)

A
  • deflection
  • torque over abutment
  • lever arm, increaed effect over anterior
  • luxation
163
Q

What factors influence how much a bridge bends?

A
  • length of the bridge
  • thickness of the bridge
  • curvature of the bridge
164
Q

How does the length of a bridge effect how much it bends?

A
  • Bending is directly proportional to the cube of the length (the dentulous span)
  • longer=bendier= more risk of failure
165
Q

How does the thickness of a bridge effect how much it bends? (3)

A
  • The thickness will reduce the degree of the deflection
  • Occluso-gingival thickness is the one that matters.
  • Inversely proportional to the cube of the thickness.
166
Q

How do you minimze torque over abutments? (4)

A
  • Thicker pontics occluso-gingivally
  • More rigid alloys ( Ni-Cr, Zr)
  • Using more than one abutment tooth.
  • thicker framework of the pontic
167
Q

How do thicker framework of the pontics minimize torque over abutments for PFM crowns?

A

gingival or occlusal surface of the pontic made of metal

168
Q

What to remember about thicker pontics minimizing torque over abutments?

A

Modifying the antagonist arch if necessary

169
Q

How do more rigid allows minimize torque over abutments?

A
  • Predominantly base alloys more rigid than:
  • Noble alloys more rigid than:
  • High noble alloys.
170
Q

When should you use more than one abutment to minimize torque? (3)

A
  • Esp when abutment doesnt have proper crown-to-root ratio
  • Teeth further away from center suffer more torque
  • conditions of secondary abutment are equal to primary
171
Q

What forces does the secondary abutment have to support?

A

Must support tensile forces when the pontic flexes

172
Q

Characteristics of the secondary abutment ? (4)

A
  • Crown-to-root ratio: equal or bigger than the 1º
  • Bone support: equal or bigger than the 1º
  • Periodontal health: better or equal
  • Retentive capacity: higher or equal
173
Q

Embrasures between retainers on bridges must allow…

A

Correct hygiene

174
Q

Why is the curvature of the arch important for a bridge??

A
  • has an effect on the stress
175
Q

When does a bridge have more risk of torque with the curvature of the bridge? (3)

A
  • When the pontics are away from the line that joins the retainers
  • produces lever action over the abutment
  • the longer the lever arm, the more torque and luxation
176
Q

How do you replace upper incisors in a bridge? (2)

A
  • Pronounced curvature

- to offset torque: gain retention on the opposite direction of the lever arm

177
Q

What are the different bridge options based on what teeth are missing? (3)

A
  • Simple
  • Complex
  • Special
178
Q

When do you use a simple bridge?

A
  • Replace only one tooth

- both incisors or both premolars missing

179
Q

What type of bridge do you use if the first premolar is missing? (4)

A
  • Simple bridge
  • use 3 & 5 as abutments
  • Group function
  • cantilever could be used but its not recommended
180
Q

What type of bridge do you use if the second premolar is missing?

A
  • simple bridge
181
Q

What type of bridge do you use when the central and lateral incisors are missing?

A

Simple bridge:

  • Maryland bridge
  • Conventional bridge

Complex bridge

182
Q

What type of bridge do you use when the premolars are missing?

A

Simple bridge

183
Q

What type of bridge do you use when the second premolars and first molar are missing?

A

Simple bridge

184
Q

What is a complex bridge?

A
  • Two or more pontics

- in a more committed location

185
Q

Why are complex bridges more demanding? (3)

A
  • toughness of retainers
  • abutments
  • periodontal support
186
Q

What type of bridge do you use when replacing lower incisors?

A
  • Complex bridge (four pontics)
187
Q

In which type of bridge can you use a 3rd molar as an abutment?

A
  • Complex bridges

Problematic b/c:

  • incomplete eruption
  • short & fused roots
  • mesially inclined
188
Q

When do you choose a secondary abutment in complex bridges?

A
  • All the abutments must have the same retention.
  • Also when there is a reduced periodontal support.
  • They have to support a certain amount of flexes depending on the forces applied over the pontics.
189
Q

What bridge do you use when a canine is missing?

A
  • Complex bridge
  • difficult because of canine guidance
  • group function occlusion
  • use both incisors as abutments and 1st premolar
190
Q

What bridge do you use when a lower central and lateral incisor is missing?

A

Complex bridge

191
Q

What bridge do you use when the upper central incisors are missing?

A

Complex bridge

192
Q

What bridge do you use when the first and second premolars are missing?

A

Complex bridge

193
Q

What bridge do you use when second premolars and first molar are missing?

A

Complex bridge

194
Q

What bridge do you use when the lateral incisor and canine are missing?

A
  • Complex bridge
  • 3-4 abutment teeth
  • group function
195
Q

What bridge do you use when more than 2 upper incisors are missing?

A

Complex bridge

196
Q

What bridge do you use when both premolars and first molar are missing? (4)

A

Complex bridge

  • only if abutments are in perfect condition
  • canine guidance
  • rigid alloy (Ni-Cr)
197
Q

What is a special bridge?

A
  • has an intermediate abutment
198
Q

What is an intermediate abutment

A
  • There are two spaces next to a tooth

- abutment suffers more

199
Q

It is important that intermediate abutments are…

A

Periodontically sound

Have lots of healthy tooth structure

200
Q

Do you use interlocks on special bridges?

A

Used to use them, not any more

201
Q

Special bridges and inclined abutment teeth? (5)

A
  • Specially lower 2nd molar.
  • Very difficult to get a common path of insertion.
  • Endo post might be needed
  • Ortho treatment.
  • Telescopic crown.
202
Q

What bridge do you use if a canine and one other tooth is missing?

A
  • Special bridge

- Group function

203
Q

What bridge do you put if a canine and 2 teeth are missing?

A

No bridge, RPD or implants

204
Q

When can you use a cantilever bridge? (4)

A
  • special bridge
  • upper lateral incisor
  • 1st premolar missing
  • first molar missing
205
Q

Upper laterial incosr and cantilever bridges?

A
  • Lateral incisor shouldn’t participate in canine guidance
206
Q

First molar missing and catilever bridges?

A

Avoid

if no other options, then reduce it MD

207
Q

Do we splint special bridges?

A

Avoid whenever possible

  • hinders hygiene
  • all treatment can be committed because of one tooth
208
Q

When should we splint special bridges? (3)

A
  • periodontal reasons
  • tooth with very short clinical crown
  • combined prothesis
209
Q

Full mouth rehabilitations and splinting?

A

Splinting as one single bridge should be avoided.
◦ It’s difficult to achieve a good fit.
◦ Hindered hygiene.
◦ All the treatment can be committed because of one tooth.
◦ Mandible bending movement.

210
Q

Full mouth rehabilitations and special bridges?

A

Divide bridges into sectors:

  • anterior on one side
  • posteriors on other

Prostho 3 (11 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions