Operative Final Exam - Lectures: Amalgam Restorations and Quadrant Dentistry Flashcards
If the mouth was divided into a sextant, how many sections would there be and name their location.
- 6 sections
- maxillary left, right, and anterior
- mandibular left, right, and anterior
What is quadrant dentistry?
treating all of the affected teeth in 1 quadrant/sextant during the same visit as opposed to 1 tooth at a time
What are the advantages of quadrant dentistry?
- less number of appointments for patient
- less discomfort for patient
- more efficient and productive for dentist
What are the disadvantages of quadrant dentistry?
- increased chairside time
- does not follow the ideal treatment sequence (3 phases: get the patient out of pain, remove caries, and then restorative care)
What are some reasons to perform (indications) quadrant dentistry?
- adjacent interproximal caries (“kissing caries)
- multiple faulty restorations
- pediatric dentistry
- medically compromised patients
What are some reasons not to perform (contraindications) quadrant dentistry?
- lack of dental experience
- patient who have TMJ dysfunction syndrome
- patients who cannot stay in a reclined position for a long time
What is the formula of a low-copper amalgam?
Ag3Sn (gamma) + Hg –> Ag2Hg3(gamma1) + Sn7-8Hg(gamma2) + Ag3Sn (unreacted gamma)
What is the weakest phase of low-copper amalgam?
gamma2
What is the most corrosion-prone phase in low-copper amalgam?
gamma2
Which type of amalgam (high or low copper) has high creep? Why?
low-copper because gamma2 doesn’t prevent gamma1 from sliding
What is creep?
the tendency of a solid material to flow or permanently deform under constant cyclic loading over time
What percentage of copper is considered a low-copper amalgam? A high-copper amalgam?
- low-copper amalgam = 6% Cu
What is the difference in phases between high-copper and low-copper amalgams?
high-copper amalgam has a n’ phase of Cu6Sn5 so there is no gamma2
What is the composition of gamma?
Ag3Sn
What is the composition of gamma1?
Ag2Hg3
What is the composition of gamma2?
Sn7-8Hg
What is the composition of n’?
Cu6Sn5
What are the two types of high-copper amalgams?
- admixed alloy (lathe-cut and spherical)
- unicompositional (spherical)
What is the difference in the reaction formula of admixed alloy and unicompositional high-copper amalgams?
- admixed alloy has two steps: first step in which gamma2 forms and then second step in which n’ forms so no gamma2 is left
- unicompositional is only one step in which n’ forms (in addition to gamma1)
How is creep minimized in high-copper amalgam?
the n’ phase prevents the sliding of gamma1 to minimize creep and marginal breakdown
Which amalgam particle shape (lathe-cut or spherical) requires less condensation forces since it has looser contact?
spherical
Which amalgam particle shape (lathe-cut or spherical) has a low packing density with more spaces?
lathe-cut
Which amalgam particle shape (lathe-cut or spherical) has a higher surface area so more Hg and more expansion?
lathe-cut
Which amalgam particle shape (lathe-cut or spherical) packs more efficiently and slides easier to make less voids and higher strength?
spherical
Which amalgam particle shape (lathe-cut or spherical) is difficult to achieve proximal contact?
spherical
Which amalgam particle shape (lathe-cut or spherical) requires a large diameter condenser for proper condensation?
spherical
What type of amalgam is used at OSU? Describe it.
- Permite C
- high-copper amalgam
- admix type (spherical and lathe-cut)
- zinc-containing (0.2%)
What is the problem with zinc-containing amalgams?
if moisture contaminates, it will cause delayed expansion
What is the difference between direct and indirect restorations?
- direct restorations are placed directly in the oral cavity as a soft plastic material to build lost structure before they set hard
- indirect restorations are fabricated outside the oral cavity (like crowns)
True or false: A rubber dam is not necessary in quadrant dentistry.
FALSE. A rubber dam is a prerequisite of quadrant dentistry.
What should you do if you have multiple adjacent Class II preps when performing quadrant dentistry?
restore two non-adjacent teeth first and then do the teeth in between
When doing a back-to-back Class II amalgam restoration in quadrant dentistry, what are the two methods you could use? Which is recommended?
- Method 1: band and restore the Class II preps simultaneously
- Method 2: band and restore each tooth separately, one preparation at a time starting with the most posterior tooth
- Method 2 is recommended.
What is flash?
when excess amalgam is covering the cavosurface margin
What is the definition of submarginal in amalgam restorations?
the amalgam doesn’t reach the cavosurface margin
What is the definition of an open margin in amalgam restorations?
the amalgam is at the right height with the cavosurface margin except right at the edge of the restoration where a chunk is missing
What are the steps of an amalgam restoration?
- activation
- trituration
- placement
- condensation
- carving
- finishing
- polishing
What are the characteristics of under triturated amalgam?
- incomplete amalgamation
- poor working quality
- granular and crumbly
- decreases final strength
What are some characteristics of over triturated amalgam?
- decreases final strength
- overly warm and shiny
- decreases working time
True or false: Deep occlusal grooves should be avoided when carving.
true because this thins the amalgam at the margins
A faint marking is left on the opposing tooth after an amalgam restoration was completed. Should the amalgam be carved down?
No. You don’t want to take the amalgam completely out of occlusion. You carve down if a patient says that they can feel it or if there is a heavy marking like a bullseye/halo/doughnut.
What are the two types of matrix bands? What is the difference between the two?
- No. 1 - normal (like we use in lab)
- No. 2 - has gingival extensions for preps that are extended occlusogingivally
What are the purposes of a matrix band?
- provides a wall against which one can condense amalgam
- re-establish proximal contact of restoration with adjacent tooth
- aids in isolation of preparation during the fill
- provides containment of the amalgam
- aides in prevention of voids
- helps to shape the proximal contacts
What are the two types of Tofflemire retainers?
- contra-angle
- straight
Which Tofflemire retainer is usually used on the buccal side of a tooth? Which on the lingual side?
- contra-angle on the lingual
- straight on the buccal
What are the functions of a wedge?
- adapts the gingival edge of the matrix band against the gingival cavosurface of the preparation to prevent flash from squeezing out gingivally
- spearates the teeth slightly to compensate for the thickness of the band
- helps stabilize the band
What is the purpose of trituration?
to remove the oxide coating and wet each particle of alloy with mercury
How much pressure is necessary to place amalgam?
5-10 lbs
What does burnishing amalgam do?
- a form of final condensation
- removes mercury-rich excess at surface
- begins development of occlusal grooves and fossae
How is amalgam carved: from tooth to amalgam or amalgam to tooth?
tooth to amalgam
