Week 8 Class II Restorations Flashcards
what does caries on the axial wall indicate
only remove caries
what does caries on the pulpal floor indicate
widening of the prep but dont deepen. use a round bur or spoon excavator to remove caries and accept an irregular pulpal floor
what do you do if recurrent caries extends gingivally in the box area
you can make a box within the box rather than deepening the entire box
how should liner be placed
only to the deepest part of the prep closest to the pulp and keep it away from the margins
what are the liner materials, when do you use them and what are the names
-calcium hydroxide: Life, Dycal, use on deepest preps- pulp capping material
- resin modified glass ionomer: vitrebond, light cured, releases fluoride over time
restoration should be supported by at least ___
a tripod of structure
why should the entire floor not be covered by calcium hydroxide
CaOH is too soft to support the restoration
when can the entire pulpal floor be covered with the material
if the material is hard when set like a glass ionomer but the material must rest on a tripod of dentin
what are the functions of a good matrix band
- enough rigidity to resist too much deformation by packing forces or wedging but is slightly burnishable and displacable
- assists in establishing proper anatomical contour
- must prevent excess amalgam from being expressed at the gingival margin as much as possible so you dont get gingival overhand that will trap plaque and irritate the gingiva
- must be convenient to install
- must be easy to remove and allow for removal without breaking a partially set amalgam
what are the 3 choices for putting the tofflemire on
-retainer on buccal side and band emerges from one side of guide channels (more common)
- retainer on lingual side, requires use of a contra angle retainer, useful with missing buccal tooth structure
- band emerges through the middle channel. the retainer is on the lingual. useful when there is missing buccal structure and used more in maxilla than mandible because of tongue
what are the steps of inserting band into tofflemire
- turn the inner nut counterclockwise until slot vice is about 1/4inch from guide channels
- hold inner nut and turn the outer nut counterclockwise until the pointed end of the spindle is free of the slot in the slot vice
- double the band back on itself forming a loop
- insert into the slot vice and direct it through one of the three guide channels. tighten spindle
what do you do if gingival tissue gets caught between the matrix band and the gingival margin
move the matrix band in an occlusal direction, place a hollenback carver between the matrix band and the tissue, deflecting the tissue and reset the band
where should the wedge be placed
through the more open of embrasures- usually lingual
what are the special considerations when wedging
- choose right size
- dont allow the wedge to force the band into the box or areas that should be filled with amalgam
- if prep is deep gingivally and band wants to jump up on the box, ue a hollenback carver to support the band and allow it to seat far enough gingivally for wedging
- if wide interproximal and deep box you can double wedge
- if gingival recession you can double wedge vertically
what do you do if no standard wedge will close the gingival margin without distorting the band
use a bur or sharp blade to reshape the wedge
how should you obtain a good contact with the band
- loosen the band a quarter turn after wedging
- burnish the band against the proximal surface of the adjacent tooth
- scrape with an explorer along the tooth metal interface at the gingival margin to remove tissue or debris in this area. flush and dry
- if band is still not against tooth, loosen retainer more and burnish again
- pack amalgam hard against matrix band
what are the steps to placing the amalgam
- burnish the matrix band against the adjacent tooth and reconfirm tightness of the wedge
- loosen the inner nut 1/4 turn to assist in getting good contact. mix amalgam, dispense well and pick up with amalgam carrier
- unload only one carrier full into the box at a time, then one load in the occlusal but condense box first
- use hollenback to pack firmly into all internal line angles
- pack until overfill of 1 mm
- pre carve/burnish
- use explorer at 45 degree angle to define the occlusal embrasure by trimming away the amalgam that runs up onto the matrix band
- form anatomy on occlusal
- form marginal ridge
- redefine the occlusal embrasure once more and remove wedge
describe the technique that amalgam should be condensed in the box
- pack firmly at an angle into the buccal gingival and lingual gingival line angles and all other margin areas especially. use press and wiggel technique
- be aware of the corners of the box where its easy to get voids
- condense against the contact area on the band
what are voids often the result of
placing too much amalgam in the box without condensing it the first time
how long do you have to condense
3-4 mins
what instruments should be used for pre carve burnishing
side ofhollenback condenser or large ball burnisher
how should the marginal ridge be formed
carved at the same height as the adjacent marginal ridge
- have a straight section perpendicular to the long axis of the tooth with a triangular inclined plane descending from the ridge crest into the pit
how should the matrix band be removed on a two surface amalgam
first on the non-restored surface then next to the new amalgam by sliding the band horizontally and then in an oblique oclussal direction
