Occlusion and Polishing Flashcards
Why do we finish and polish restorations?
Finishing
• Removes marginal irregularities
• Removes high spots
• Smooth away surface roughness
Polishing
• Use abrasive agents to remove roughness
• Make surface more resistant to plaque retention
• Improve or add the finishing touches to a restoration
Indications for polishing dental restorations (gingival overhang)
- Detected by radiographs
- Dental floss fraying
- Patient complaining of ‘food impaction’
- Gingival tissues appear inflamed in the area
What are the indications for polishing amalgam?
- There is no need to routinely polish amalgam restorations
* Only for high spots or plaque retentive area
What are the indications for polishing CR?
- Surface roughness
- Surface discolouration
- Overhang
- Over-filled restorations
What are the contra-indications for polishing CR?
- Use of acidulated phosphate fluoride (APF) or Stannous Fluoride may cause loss of filler particles
- APF – pH 3.0-3.5, Stannous Fluoride – pH 2.1-2.3
- Other studies have shown the effect of ‘pitting’ on the composite with continuous use of APF
What can be used to to remove overhangs?
- Scalers/Ultrasonic scaler
- Flame polishing bur – make sure the polishing blade is not too long…can lacerate gingival tissue if not positioned properly
- Finishing strips/ Diamond strips: coarse to fine. Can damage soft tissue easily if not managed well
Which polishing instruments are used for amalgam?
- Brown and green rubber cups and points
- Use brown points before green
- Always polish with water to avoid generation of heat and minimise release of mercury vapour
- Pumice and water
Which polishing instruments are used for CR?
- Diamond polishing
- Tungsten carbide
- White stones
- Aluminium oxide strips and paste
- Soflex discs
- Enhance finishing points
Which polishing instruments are used for GIC?
- Cannot be ‘polished’ to the same smoothness as composite resin
- Minimal shine
- Brittle and prone to wear
Polishing GIC
• Large slow speed round bur
• Do not polish directly after restoration placement unless there is occlusion interference or significant marginal excess
• White stone (not during initial setting of GIC)
What is centric occlusion?
Ideally upper and lower teeth are in contact. Teeth are in contact uniformly and with equal pressure. It is in its habitual position “feels right”
What is lateral excursion?
Mandibular movements - left and right from centric occlusion
Why is it important to maintain an overall pattern of occlusal harmony?
- Patient comfort
- Occlusal stability
- Restoration in harmony with the existing jaw relationship, in such a way that the occlusal contacts of the other teeth remain unaltered
- Less likely to introduce problems for the tooth, the periodontium, the muscles, the temporomandibular joints (TMJ)
What are the effects of incorrect occlusion?
- Smallest occlusal interferences of just a few microns can cause serious disturbances for the patient
- Clenching and grinding can become chronic in the long term
- Premature contacts are often uncomfortable, as the proprioceptors react sensibly under pressure
- The patient will try to compensate for the occlusal interference by adapting to a new habitual position, with consequences for the attached tissue structures.
How do you check for occlusion?
describe articulating paper, and what is done pre prep and post prep
Before cavity prep:
• First: examine the occlusion before picking up a handpiece. Examination of the centric occlusion is done by asking the patient to “tap” onto a piece of thin articulating paper or foil
• Next: ask the patient to slide from side-to-side using thin paper or foil. This marks the contacts of the dynamic occlusion
After cavity prep:
• Check that the occlusion of the restoration does not prevent all the other teeth from touching in exactly the same way as they did prior
• This is best done by using a different colour of paper / foil to what was used pre-operatively
Articulating paper
• The paper is just for marking the teeth to see where they contact
• The spongelike structure of the soft micro fleece paper stores the colour, which is released under pressure
• On heavy contacts = greatest masticatory pressure - more colour is squeezed out, therefore producing dark marks
• On light contacts = slight masticatory pressure - accordingly less colour, therefore light marks
