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BDS4 restorative > Bridgework 3 > Flashcards

Bridgework 3 Flashcards

1
Q

what are the alternatives to a bridge

A

no restoration
dentures
implants

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2
Q

what sort of treatment planning needs to be carried out

A

Holistic Treatment Planning
* Look at the whole mouth
* Not only at a specific tooth
* Plan for retrievability
○ Always have a back up plan

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3
Q

what information do you want to get from taking a history

A

○ Presenting complaint
○ Medical and social history
Past dental history

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4
Q

what information do you want to get from a clinical examination

A

○ Soft tissues
○ Periodontal
○ Caries risk assessment
○ Occlusion
Parafunction

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5
Q

what information do you need about the abutment

A

○ Remaining tooth structure
○ Special tests
Radiographs

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6
Q

what sort of occlusal information do you need to gather

A
  • incisal classifcation
  • canine guidance or group function
  • opposing teeth over-erupted
  • current occlusion
  • signs of parafunction present ~ wear facets, attrition
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7
Q

what needs to be considered when designing and planning bridges

A
  • Minimal preparation or conventional preparation?
    ○ Ie conservation of tooth tissue
  • Material?
  • Abutment evaluation?
    ○ Amount of tooth tissue remaining
    ○ Is pulp status health
    ○ If RCT is it good
    ○ Any signs of infection
    ○ Periodontal condition
  • Cleansability
    ○ Bridges will fail if OH isn’t easily preformed
    ○ Cannot be plaque retentive
    ○ Needs to be easy to clean to prevent diseases
  • Appearance / aesthetics
    Confirm that the patient’s expectations are achievable
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8
Q

what needs to be evaluated with potential abutments

A
  • Get radiographs of any potential abutment teeth
    • Root configuration
      ○ Good, strong, multiple roots are able to withstand occlusal forces
    • Angulation / rotation of abutment
      ○ Can make provisional bridgework either impossible or very challenging
    • Periodontal health
    • Surface area for bonding and quality of enamel
      ○ Best chemical bond to enamel
    • Risk of pulpal damage
      ○ In relation to conventional bridgework which needs more extensive prep
    • Quality of endodontics
      ○ Re-root canal treatment
      ○ Ensure it is sufficient before starting to prep for your bridge
    • Remaining tooth structure present?
      ○ Is there enough for good retention etc
      ○ Do you need to consider composite core build ups
    • Core
      Remove and rebuild?
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9
Q

what are the 3 types of bridge design

A
  • resin-bonded / resin-retained / adhesive
  • conventional
  • hybrid
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10
Q

what are the types of resin-bonded bridges

A
  • cantilever
  • fixed-fixed
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11
Q

what are the types of conventional bridges

A
  • cantilever
  • fixed-fixed
  • fixed-moveable
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12
Q

what details need to be decided when designing a bridge

A
  • Select abutment teeth
    ○ Judge longevity of adjacent teeth
  • Select retainer
    ○ No prep, minimal prep, regular prep? (RBBs)
    ○ Complete crown retainer? (conventional design)
  • Select pontic and connector
  • Plan occlusion
    Prescribe material
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13
Q

what are the different types of pontics

A

○ Sanitary / wash-through pontic
○ Dome / bullet / torpedo
○ Modified ridge lap
○ Total ridge lap (full saddle pontic)
○ Ovate pontic

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14
Q

what is the function of pontics

A
  • Restore appearance of missing tooth
    • Stabilise the occlusion
      Improve masticatory function
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15
Q

what considerations need to be given to pontic design

A
  • Cleansabilty
    ○ Should always be smooth, with highly polished or glazed surface
    ○ Surface should not harbour join of metal and porcelain
    § (if metal-ceramic design used)
    § Don’t want an occlusal force acting where the join is
    ○ Embrasure space smooth and cleansable
    • Appearance
      ○ Anteriorly - as tooth like as possible
      ○ Posteriorly - may compromise
      § More likely to be more concerned with function than appearance
    • Strength
      ○ Longer the span = greater the thickness required to withstand occlusal forces
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16
Q

what should the occlusal surface of a pontic be like

A

Resemble surface of tooth it replaces
narrower if possible to enable cleaning
Should have sufficient occlusal contact so that it is actually functional and so that the occlusal forces are actually driven down the tooth longitudinally in a safe manner

17
Q

what should the approximal surfaces of a pontic be like

A

○ Connector: strength
§ Needs to have a good thickness of connector
§ Ideally should be about 2x2mm for adequate strength

○ Embrasure: space
§ In some cases you might want to try and reduce the embrasure space in a highly aesthetically demanding case
§ In other cases however you want to leave a little space to ensure there is some cleansibility so patients can get floss and interdental brushes in these areas
Need to have a bit of a balancing act

18
Q

what surfaces allow for some variation in design with the pontic

A
  • Buccal and lingual surface
    ○ They can change a little depending on the pontic design, especially the lingual surface
    • Ridge surface
      ○ Ie the fitting surface
      Can have some variation depending on your choice of pontic
19
Q

what is the wash-through pontic design like

A

○ Makes no contact with soft tissue
§ Functional rather than for appearance
§ Consider in lower molar area
○ Almost like it is floating away from the alveolar ridge, makes no contact with the soft tissues which overlie the ridge form
○ This is only to give an additional occlusal surface to bite on
§ Functional and not for aesthetics
Because of the space between the pontic fitting surface and the soft tissues underneath it is very easy for things to pass through it therefore making it very easy to clean

20
Q

what is the dome-shaped pontic like

A

○ Useful in lower incisor, premolar or upper molar areas
○ Acceptable if occlusal 2/3 of buccal surface visible
§ Poor aesthetics if gingival 1/3 of tooth visible
Ie upper 2/3s of pontic look as tooth like as possible but the lower 1/3 (the more apical 1/3) is more narrowed in a bit so it doesn’t look as much like a real tooth but this helps with the cleansibility

21
Q

what is the modified ridge lap pontic like

A

○ Buccal (or labial) surface looks as much like tooth as possible
○ Lingual surface cut away
§ Makes tooth like from the facial perspective but also give a little space to try and get something in on the lingual / palatal aspect in order to clean
○ Line contact with buccal of ridge
○ Problems with food packing on lingual surface of ridge
Ie potentially more cleansible but also more prone to packing

22
Q

what is the ridge lap / saddle pontic like

A

○ Greatest contact with soft tissue
§ Although it presses on soft tissue and can cause some blanching in the area temporarily, it is not as accessible for food to get packed underneath it essentially
§ Need a patient who is good with their oral hygiene and is quite motivated to keep it up
§ However, likely to cause problems in patients who oral hygiene is not as good
□ Can get food packing and plaque accumulating under the fitting surface and this can cause inflammation of the gingivae underneath
○ If designed carefully it can be cleansed
○ Less food packing than ridge lap
Care taken not to displace soft tissue or cause blanching of tissue

23
Q

what is the ovate pontic like

A

○ Very good for patients with meticulous oral hygiene who are also wanting to get the best aesthetic result for a bridge
○ Presses down on gingivae and causes the gingivae to mould into a little divet so then when you have the pontic sitting in that for a bit it gives an appearance of a tooth piercing through the gum like a natural tooth would
§ Sometimes this is not achievable with a single bridge; what you might need to initially do is provide an essix retainer which is like a mouth guard with an ovate pontic in it which then pushes down on the gingivae to mould it a little bit
§ If patient returns and needs more moulding can add more composite to the ovate pontic within the retainer, patient wears this and pushes harder on the gum again
§ This allows gum to get moulded again to create a deeper divet
§ If you are happy with the way the gingivae has been sculpted then you prescribe an ovate pontic in your final bridge to then sit into the little area created
○ Gives a really aesthetic appearance
Patient needs really good oral hygiene to get in and around pontic for cleaning

24
Q

what materials can be used for conventional bridges

A
  • All metal
    ○ Gold
    ○ Nickel / cobalt chrome ?
    ○ Stainless steel
  • Metal ceramic
    ○ Aesthetic component and strength component
  • All ceramic
    ○ Zirconia
    ○ E.g. LAVATM and Procera®
    ○ Lithium disilicate
    ○ E.g. - E.max
  • Ceromeric
    • BelleGlass™
    • Vectris®
    • Targis® Vectris®
    • Not used a lot anymore for brdigework
    • Basically porcelain combined with composite
      ○ Ie composite can withstand occlusal forces than ceramic because it is not as brittle when it is subjected to force
      ○ However, composite doesn’t look quite as nice as porcelain
      Slightly better aesthetic and mechanical properties
25
Q

when is gold a good material to use

A
  • Gold especially in lower posterior area
    ○ Good because subjected to a lot of occlusal forces
    ○ Not an area where there is a high aesthetic demand
    Gold is a malleable metal so withstands forces well
26
Q

what is the majority of bridges constructed in the UK made from

A

Metal ceramic

Metal substructure to give robustness to bridge
Layers of porcelain to improve aesthetics

27
Q

what is LAVA TM 3M ESPE used and why

A
  • 3-4 unit fixed bridge (maximum span) milled zirconium oxide frame with feldspathic porcelain overlying
    • Withstand occlusal forces
      • Very strong
      • Starting to rival metalwork
    • Good aesthetics
    • Similar reduction to MCC
    • Example of a LAVA bridge
      All ceramic material
28
Q

what is zirconia and when is it used

A
  • GDH&S fixed pros lab now producing more all ceramic restorations
    • Preparations on casts can be scanned
      • Straűmann© – 7 Series by Dental Wings
      • Nobel BioCare © – Series 5
    • KATANA© zirconia
      • Multilayered (ML) zirconia
      • Ultra translucent multilayer (UTML) zirconia
    • Milled
    • +/- feldspathic (layer) porcelain on top
      • Can be on the facial aspect above zirconia to give a better aesthetic appearance
    • Aesthetics of these are improving
      Because it comes in one block used to just get the one shade of teeth but it is now available in a block with layers of shades within it
29
Q

when are implant retained bridges used

A

Large-span bridges

30
Q

what are the steps in preparing conventional bridgework

A
  • Mounted study models
  • Consider diagnostic wax-up and custom impression tray
  • Request lab to construct vacuum-formed stent
  • Allows checking of reduction during tooth preparation
  • Allows construction of provisional bridge
  • Select shade
  • Before you cut the teeth
  • Use adjacent teeth as basis
  • Lab made stent or make pre-op putty impression for provisional bridge
  • Occlusal or incisal reduction
  • Separation of teeth
  • Aim for parallelism of tapered surface of each preparation
  • Confirm parallelism
  • Consider retentive features if short clinical crown height or overtapered
  • If this happens you have compromised your retention so then you need to consider:
    ○ Slots
    ○ Grooves
  • Construct provisional bridge
  • Once you are happy with your preparation you can do this
  • Make impression and occlusal registration
  • Always ensure you have the provisional crown or bridge before you start attempting impressions for the definitive restoration
  • Temporarily cement provisional bridge
  • Demonstrate cleaning with superfloss
  • Write / draw prescription for technician
31
Q

when should parallelism be considered

A
  • Consider for fixed-fixed conventional bridge
    * Requires 2 or more teeth to be prepared in a manner to provide a common path of insertion - increased retention
    * No undercuts
    ○ Be mindful that this is something you do not create
    ○ Can lead to more tooth tissue loss (more destructive)
    Want to have a single path of insertion ie bridge can only go on one way therefore can only come off one way
32
Q

how do you do paralleling by eye

A
  • Direct vision, one eye closed
    * Large mouth mirror posteriorly
    * Use a straight (right angle) probe like a lab surveryor, but in the mouth
    If it is not parallel you would see a gap between the tooth and the probe when you compare the angles of the same surfaces of both abutment teeth
33
Q

what do you use for definitive cementation

A
  • All metal conventional bridgework
    * Aquacem (GI luting cement)
    * RelyX™Luting (RMGI luting cement)
    • Metal ceramic
      • As above (metal substructure)
    • Ahesive / resin-bonded / resin-retained bridgework (all types)
      • Panavia 21 (anaerobic duel cure resin cement with 10-MDP)
        ○ 10-MDP helps tooth stick to metalwork
      • Resin bonded bridge = want to use composite based material
    • All ceramic
      NEXUS® kit (duel cure resin cement)
34
Q

can distal cantilevers be used

A
  • Avoid if possible
    * When patient bites together they will probably make an initial contact on the most distal aspect of the restoration
    * So if that is your pontic you’re going to get initial contact on that which creates a see-saw effect which then lifts up the retainer which is on the more mesial tooth
    • Concern that occlusal forces on pontic will produce leverage forces on abutment tooth causing it to tilt
    • May consider distal cantilever from premolar abutment if unopposed or opposed by a denture
      • This is not to say that they cannot ever be done because they can be seen in patients who only have 4 to 4 and you want to give them 5 to 5 basically by adding on distal cantilevers
        = shortened dental arch (10 pairs of occluding teeth)
35
Q

longevity of resin-bonded bridges at 5 and 10 years

A

~ 80%

36
Q

longevity of conventional fixed-fixed metal ceramic bridges at 5 and 10 years

A

5 - 93%
10 - 89%

37
Q

longevity of conventional fixed-fixed ceramic bridges at 5 years

A

88%

38
Q

longevity of conventional cantilever bridges at 5 and 10 years

A

5 - 91%
10 - 80%

BDS4 restorative (4 decks)

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