#8 CIII RC Bevel.png

Class III Resin Composite Preparation

#8 ML

Overview

Outline Form
Resistance Form
Retention Form
Convenience Form
 
 

Armamentarium

Instruments and Materials

Class_III_Prep_Arm.png
 

Video Demonstration

Procedure

 

Select the appropriate resin composite shade using the shade-matching guide or clinical judgement

  • Clinical note: Perform shade selection with natural light prior to isolation of the tooth

Untitled_Artwork 89.png

Envision the cavity preparation outline and extent

  • 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

Class%20III%20caries-2_edited.png

*Radiographic caries superimposed on preparation

Optional: Draw the outline of the cavity preparation using the red-blue pencil

Untitled_Artwork 18.jpg

Obtain isolation of the tooth (e.g. rubber dam, isovac/isolite, etc.)

          

Untitled_Artwork%25207_edited_edited.jpg

Position the mirror to achieve indirect vision of the preparation

indirect%252520vision_edited_edited_edit

Place a wedge in between the adjacent teeth to separate the contact areas 

  • Optional: Place a matrix band interproximally to protect the adjacent tooth from iatrogenic damage

DSC_0010%25252520copy%25252520(1)_edited

Orient the bur perpendicular to the lingual surface of the tooth, close to but without touching the adjacent tooth   

  • Clinical note: Position the bur over the carious lesion or existing, faulty restoration

Bur options: pear shaped carbide bur (330)

Untitled_Artwork%25203-2_edited_edited.j

Penetrate the tooth to an initial facio-lingual depth of 1mm-1.5mm

F7D21D94-D688-46B8-AB75-ED2F75860BAE_1_1

Extend the preparation inciso-gingivally and mesial-distally  

  • 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

 

          

8D1C141E-BBDB-4790-A54D-07E45B2911D8_1_1

Use the probe to check for appropriate dimensions

  • 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

  • Clinical note: The final preparation dimensions are determined by the extent of the carious lesion or existing, faulty restoration

09CED662-9CE9-4C05-A3FE-F9CC538D061A_1_1
7D29ECC4-FBF0-495B-B476-4A4A70DCED77_1_1

Clinical note: Check for and remove remaining caries

  • 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)

          

Untitled_Artwork 90.png

Round internal line angles using rotary instruments (high speed with water or slow speed)

 

Bur options: pear shaped carbide bur (330)

Untitled_Artwork 19.jpg

Smooth the preparation with rotary instruments (high speed with water OR slow speed) or hand instruments  

  • Remove major unsupported enamel   

  • Remove steps/ledges  

 

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

Hand instrument options: enamel hatchet, enamel hoe

          

Untitled_Artwork%2020_edited.jpg

Create a 0.25mm-0.5mm bevel circumferentially around the preparation, orienting the bur with rotary instruments (high speed with water or slow speed) at a 45-degree angle to the cavosurface margin

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

 

Bur options: coarse diamond bur (flame)

Untitled_Artwork%2018_edited.jpg

Clean and dry the preparation using the air-water syringe

Untitled_Artwork%252019_edited_edited.jp

Examine the preparation and evaluate for proper dimensions

  • Use the explorer to check for smoothness 

  • Use the probe to check for appropriate depth and width

  • Clinical note: the final dimensions of the preparation are determined by the extent of the carious lesion or existing, faulty restoration

Untitled_Artwork%2018_edited.jpg

     

  • Axial wall: flat or slightly convex

  • Facial wall: at least 90º relative to the axial wall

  • Facial depth: depends on the facio-lingual depth of the contact area

  • Preserve the facial contact​

  • Gingival floor width: 1-1.25mm

  • Incisal floor width: 1.25-1.5mm

  • Inciso-gingival length: 2-2.5mm, no greater than 3mm

    • Depends on length of contact area​

  • Preserve the incisal contact

  • Gingival contacts broken by: ~0.25mm 

C3 com prep.jpeg

*Hover for summary details

 

Checklist

Progress

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.