Class III Composite Preparation

#8 ML

Overview

  • Outline Form

    preparation outline is determined by the extent of the carious lesion, defects, or old restorative material

  • Retention Form

    obtained through micromechanical bonding of tooth structure to restoration material

    *beveling increases tooth structure available for bonding

  • Resistance Form

    rounded box form provides greater resistance to fracture of the restoration and tooth from masticatory forces

  • Convenience Form

    appropriate access to the interproximal lesion is gained from the lingual or buccal surface

Armamentarium

Instruments and Materials

Video Demonstration

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Procedures

A
  • Clinical note: Perform shade selection with natural light prior to isolation of the tooth
B
  • Clinical notes:
    • Preparation measurements are determined by the extent of the carious lesion or existing, faulty restoration
    • Class III procedure is performed when caries extends past enamel into dentin. Therefore, the mesial-distal width of the preparation will be at least 0.2 mm into dentin

    *Radiographic caries superimposed on preparation

C
D
E
F
  • Optional: Place a matrix band or metallic fender wedge interproximally to protect the adjacent tooth from iatrogenic damage
G
  • Clinical note: Position the bur over the carious lesion or existing, faulty restoration
    ​

Bur options: pear shaped carbide bur (330)

H
I
  • Facial wall is at least 90º relative to the axial wall
  • Optional:
    • ​Leave a small “enamel shell” interproximally
    • Break the enamel shell with a hand instrument​
  • Clinical note:
    • Extension should remove the carious lesion or existing, faulty restoration

Hand instrument options: enamel hatchet, enamel hoe

J
  • Inciso-gingival length: 2-2.5mm, no greater than 3mm, depending on the length of the contact
  • Gingival floor width: 1-1.25mm
  • Incisal floor width: 1.25-1.5mm
K
L
  • Assess for remaining caries using the explorer or spoon excavator
  • Remove remaining carious tooth structure using the largest round bur that fits into the preparation with rotary instruments (slow speed) or a spoon excavator

Bur options: round carbide burs (4, 6)

M

Bur options: pear shaped carbide bur (330)

N
  • Remove major unsupported enamel
  • Remove steps/ledges

Bur options: straight fissure or pear shaped carbide (556, 330)

Hand instrument options: enamel hatchet, enamel hoe

O
  • Do not bevel in areas subject to masticatory forces (e.g. incisal contact)

Bur options: coarse diamond bur (flame)

P
Q
  • Use the explorer to check for smoothness
  • Use the probe to check for appropriate depth and width
  • Clinical note: The final depth of the preparation is determined by the extent of the carious lesion or existing, faulty restoration

Checklist

References

Hilton, T. J., Ferracane, J. L., & Broome, J. C. (2013). Summitt’s fundamentals of operative dentistry a contemporary approach. Quintessence Publishing Co. Inc. 
Ritter, A. V., Boushell, L. W., Walter, R., & Sturdevant, C. M. (2019). Sturdevant’s art and Science of Operative Dentistry. Elsevier. 

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