Class IV

Question 1

what are the indications for class IV composite restorations

Answer 1

• carious lesion involving the incisal edge or undermines the enamel of the incisal edge of an anterior tooth
• trauma fracture involving one or both incisial angles of an anterior tooth

Question 2

what should be assessed in a carious class IV lesion

Answer 2

• determine vitality
• evaluate extent of caries and presence of other lesions or defective restorations on the tooth
• examine radiographs for periapical lesions
• determine size of the pulp chamber
• determine shade of tooth and adjacent teeth using Vita shade guide

Question 3

what should be assessed in a Class IV trauma lesion

Answer 3

• determine cause of fracture and time (history) of occurrence
• determine vitality
• evaluate extent of fracture and integrity of the tooth as well as discoloration
• determine presence of carious lesions or defective restorations on the tooth
• examine tooth/radiographs for root fractures, buccal/lingual plate fractures, and integrity of adjacent teeth

Question 4

how are carious class IV lesions prepared

Answer 4

• anesthetize tooth
• isolate tooth - rubber dam, isovac
• remove unsupported enamel with carbide/diamond bur
• remove all caries with largest round bur that will fit in the space
• place a liner (RMGI/CaOH) if preparation is within 0.5mm of the pulp
• place retention points if needed
• bevel all enamel margins with a medium grit diamond bur
  -place 45 degree bevel on lingual and interproximal margins
• place long, shallow bevel on the facial surface

Question 5

how do you prepare a trauma class IV lesion

Answer 5

• anesthetize tooth
• isolate tooth
• remove unsupported enamel with carbide/diamond bur
• place a liner (RMGI/CaOH) if preparation is within 0.5mm of the pulp
• place retention points if needed
• bevel all enamel margins with a medium grit diamond bur
• place 45 degree bevel on lingual and interproximal margins
  -place long, shallow bevel on facial surface

Question 6

how do you restore class IV lesions

Answer 6

• verify shade- place a small amount of composite on facial surface of tooth and light cure
• place mylar matrix strip between adjacent teeth and carefully wedge in place
• etch surface of tooth
• enamel can be etched for 30 seconds or longer
• dentin must not be etched for longer than 15 seconds
• dry excess water from enamel surface; dentin surface must remain moist to ensure maximum bond strength
• bond agent applied to all enamel and dentin surfaces
• air dry for 5 seconds with gentle stream from air/water syringe
• second coat of bonding agent applied
• air dry for 5 seconds
• light cure all areas of tooth for 20 seconds
• place first increment of composite to restore most lingual surface of the tooth to include incisal edge
• cure for 40 seconds
  -place second increment of composite to restore the labial surface of the tooth
• include the contact and incisal angle to mirror adjacent tooth surface
  -place developmental grooves on facial surface of tooth
  -place proper contour of tooth to include all line angles
• cure for 40 seconds

Question 7

how do you finish class IV restorations

Answer 7

• final shaping of facial surface is accomplished with a 7902 finishing bur
• lingual surface is shaped with a #4,6 carbide burs on a slowspeed handpiece (less than 10,000 rpm) and a 7460 finishing bur (highspeed)
• occlusion is adjusted with articulating paper and #4,6 carbide burs on a slowspeed handpiece

Question 8

how do you polish a class Iv restoration

Answer 8

• soflex discs are used to finish and polish restoration
• a series of four discs (yellow, light orange, orange, dark orange)
• do not use the dark orange disk, it is too course and will remove composite very quickly even on slowspeed
• break the spine of the disks before use
• always use the disks when wet and at very low rpm creating a slurry
• avoid holding the disc flat against the tooth this will remove tooth anatomy- hold at a 45 degree angle
• polish with the orange and light orange removing all scratches
• polish with diacomp points
• finish polish with yellow soflex disc
• remove excess composite from margins and interproximal areas with #12 surgical blade
• optiguard may be placed and cured to seal restoration

Question 9

what are the diacomp points and how should they be used

Answer 9

• green diacomp points (wet, slowspeed)
• white diacomp points (wet, slowspeed)