2/29: Class II Preparations Flashcards
Where are initial caries?
Entirely in enamel (E2, ICDAS2)
Where are moderate caries?
Lesion entering dentni (D1, ICDAS 3)
What are advanced caries?
Well into dentin, approaching pulp (D3, ICDAS 5)
What are root caries?
Lesion entering dentin (D3, ICDAS 5)
What is a dentists goal when working with interproximal caries?
- Remove carious tooth structure
- Remove least amount of tooth structure possible
- Prepare the tooth in a way that
- RESISTS fracture
- Restorative material and tooth
- =RESISTANCE form
- RETAINS the restoration
- = RETENTION form
- Is possible clinically without detriment to patient or dentist
- = CONVENIENCE form
What does the reverse S curve improve?
Resistance to amalgam fracture
What is the history of composite?
1960- first used in posterior
◦ Color change
◦ Wear
◦ Microleakage
◦ Recurrent decay
◦ Polymerization shrinkage
◦ Placed in bulk rather than incrementally
1970- recurrent decay continues to be an issue
1980- less wear, recurrent decay still a problem
1990- improving
2010- continues to improve, may be overused?
2007: Amalgam > composite
◦ composite 7 times more likely to need repairs
◦ Recurrent caries 3.5 times greater risk
◦ Pediatric patients
2018: A little less clear
What are indications for composite?
Esthetics
◦ Anterior teeth
◦ Facial of premolars or first molar
◦ Patient desire
Light occlusal contacts
◦ Must have centric TOOTH SUPPORTED occlusion on marginal ridges and cusp tips
◦ Composite does not support occlusion
Smaller restorations
◦ Class I occlusal, buccal pits, lingual pits
◦ Excellent prognosis
◦ Low stress areas
◦ Premolars > molars
◦ Small Class II restorations
◦ Keep margins in enamel
◦ Don’t forget to bevel enamel
◦ = MINIMIZE microleakage and post-operative sensitivity
Isolation
What are possible indications for composite?
Special situations
◦ Crown foundation
◦ “Buildup” material
◦ Very large restorations
◦ To strengthen remaining weakened tooth structure
◦ Economic reasons or provisionally
◦ Conservative or Preventative restorations
◦ Can preserve tooth structure
◦ May be in conjunction with sealants
◦ Temperature sensitivity with metal restorations
◦ Cross reaction between nickel allergy and silver
◦ RARE and controversial
What is not an indication for composite?
Mercury fear
◦ Educate your patients
◦ Respect their autonomy
ALS and MS patients
◦ Amyotrophic Lateral Sclerosis and Multiple Sclerosis
◦ Has not been conclusively shown to contribute to these conditions
◦ Multiple Sclerosis Society does not recommend removal of amalgam fillings to patients with MS
What is a contraindication for composite?
Heavy occlusal forces
Occlusal contacts entirely on composite
Restorations extending to root surface
Deep subgingival margins
Diet (high acidic oral environment, high alcohol consumption)
Poor oral hygeine
Unable to isolate
Why does composite fail?
Dentin tubules
- more tubules as preps get deeper = more fluid
Adhesives
- water based adhesives undergo phase separation
Etch
- operation error- easier to etch dentin too long (collapse tubules)
Orientation of enamel vs dentin
Polymerization shrinkage
What are advantages of composite?
Esthetics
Conserves tooth structure
Bonding
- reduced microleakage and recurrent decay
- increased retention
No metal
- no mercury arguments from patients
- no corrosion
- no galvanic shocl
Can be economical
- vs. crowns and inlays/onlays
Preparation may be more forgiving
- restoration is NOT
What are disadvantages of composite?
Low modulus of elasticity
Porous
More technique sensitive placement
More time-consuming placement
Microleakage
May stick to instrument, resulting in voids
Can’t place in bulk
Expensive compared to amalgam
What does the smoothly rounded form of an S curve improve?
Resistance to amalgam fracture
Where should you enter the prep on a mandibular first premolar?
Parallel to the long axis of the tooth CROWN
- this will preserve the small lingual cusp
What does a concave axial wall compromise?
Resistance and retention form
