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					DENT 430, eportfolio Assignement #2, Class III Composite prep/resto, J. Ghahremani
          DENT 430, eportfolio Assignement #2, Class III Composite prep/resto, J. Ghahremani




                          Class III Composite
                           Preparation and
                             Restoration

                                                 Javid Ghah rema ni
                                                         DMD 2010
                                                         DMD 2010

                                                 UBC Facullty off Dentiist ry
                                                 UBC Facu ty o Dent st ry




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DENT 430, eportfolio Assignement #2, Class III Composite prep/resto, J. Ghahremani




Introduction

    Composites are presently the most popular tooth-colored restorative material in dentistry due

to its many advantages such as esthetic, more conservative and less complex preparation,

insulative, bonding to tooth structure and reparability ( Roberson, Heymann, & Swift 2006). However,

to achieve a direct restoration that best fulfill the requirements of excellent esthetics and

durability, attention to the special properties of this material and proper case selection is crucial. In

this paper, I will try to explain critical criteria and requirements of class III composite preparation

and restoration.




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DENT 430, eportfolio Assignement #2, Class III Composite prep/resto, J. Ghahremani




                                 Preparation




    From Lingual View

1. 90-Degree cavosurface,incisal/gingival walls prependicular to the long axis of
the tooth:

Tooth considerations:

90-degree proximal cavosurface ensures that no undermined enamel rods remain. This provides

the best strength to the walls and reduces the risk of marginal fracture. (Roberson, Heymann, & Swift

2006)
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   DENT 430, eportfolio Assignement #2, Class III Composite prep/resto, J. Ghahremani




   Material Consideration:

   It ensures enamel rod exposure for bonding and makes incisal and gingival walls parallel or

   divergent. This divergence produce a passive preparation required for all kinds of composite

   restorations. In this design, if debonding occurs the restoration will release and the risk of recurrent

   caries will be reduced (Summit, Robbins, Hilton, & Schwartz, 2006) .




                                                                                Incisal and gingival walls are
90-degree cavosurface                                                       perpendicular to long axis of the tooth




   How to do that:

   By using proper instruments,” the tools used dictate the shape produced” (Gardner, K. 2008), small

   parallel-sided bur (#556 or 835) and keeping movement of the bur toward the proximal and

   perpendicular to it. For refining of the margin and removing unsupported enamels, we can use

   hand instruments such as off-angle hatches.




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DENT 430, eportfolio Assignement #2, Class III Composite prep/resto, J. Ghahremani




2. Incisal extension to mid-contact:

Tooth considerations:

Since proximal caries are located gingival to proximal contacts, in conservative preparations there

is no need to remove all of the contact area. This will preserve tooth structure and integrity.

Moreover, when tooth structures are in contact in proximal surface, instead of composite and

adjacent tooth, the risk of proximal attrition will considerably be reduced. Proximal attrition (which

occurs at contact areas) can cause a reduction of the dental arch (Grippo , J.O., Simring, M.,

Schreiner, S. 2004)



Material Consideration:

By extending the incisal wall to the mid-contact, the cavity will be wide enough for better

convenience form.




              Contact area                                                   Incisal wall to mid-contact




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DENT 430, eportfolio Assignement #2, Class III Composite prep/resto, J. Ghahremani




How to do that:

First, visualizing the contact area and the final outline of the preparation then beginning of the

prep just gingival to the desired incisal wall and after gross reduction refining by off-angle hatchets.


3. Gingival extension just beyond caries (in sound tooth structure):

Tooth considerations:

Because the gingival area directly below the proximal contact is where we always have decay, we

need to open contact gingivally to explore any caries in this area and prevent recurrent caries in

future (Summit, Robbins, Hilton, & Schwartz, 2006) . Just passing the tip of the explorer is ideal in

conservative preparations.

Material Consideration:

It provides wide enough cavities for convenience form.




Passing the tip of the explorer
   in gingival contact area




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DENT 430, eportfolio Assignement #2, Class III Composite prep/resto, J. Ghahremani




How to do that:

Always be cautious in small cavity preparations and do not try to remove all of gingival wall by high-

speed bur. Again, gross reduction with proper small bur first and refining by hand instrument later.

4. Does not cross the marginal ridge:
Tooth considerations:
Transverse components of the tooth anatomy are very important structures to preserve tooth

strength and integrity (Ash, M., Nelson, S., 2002). Lingual ridges are transverse components of

anterior teeth, therefore trying to preserve this structure, wherever possible, is crucial to prevent

tooth fracture under occlusal forces.

Material Consideration:

 Confining cavity preparation to the marginal ridge will reduce the bulk of the composite, its

polymerization shrinkage and occlusal forces to the restoration. This will increase the durability of

the restoration.




Thickness of the marginal ridge




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DENT 430, eportfolio Assignement #2, Class III Composite prep/resto, J. Ghahremani




How to do that:

By using small burs and considering the width of lingual ridge during preparation.

5. Axiolingual wall parallel to the proximal surface:

Tooth and material considerations:

Since anatomy of pulpal cavity roughly follow surface of the tooth, removing even amount of tooth

structure in proximal box, prevents iatrogenic exposure of pulp or unnecessary removal of tooth on

one side. Moreover, this design provides even distribution of forces through restoration and to the

cavity walls (Summit, Robbins, Hilton, & Schwartz, 2006) .




    Axial wall and proximal surface
               are parallel




How to do that:

By trying to keep the alignment of the bur during preparation and make the path of preparation

parallel to the proximal surface. We can use bi-angle chisel or off-angle hatchet to refine the axial

wall.

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DENT 430, eportfolio Assignement #2, Class III Composite prep/resto, J. Ghahremani




6. Incisal and gingival floors are parallel:

Tooth considerations:

As mentioned in section 1, in conservative preparations 90-degree cavosurface makes incisal and

gingival floors parallel.

Material Consideration:

Parallel incisal and gingival floors enhances the retention and resistance form, makes cavity more

even and distributes force better to cavity walls.




    Parallel incisal and gingival floors




How to do that:

By trying to keep the alignment of the parallel-sided bur during preparation form mesial to distal

and refining with off-angle hatchet.




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DENT 430, eportfolio Assignement #2, Class III Composite prep/resto, J. Ghahremani




 7. Rounded internal form:

Tooth considerations:

Rounded internal form reduces the stress in internal line angles and the risk of tooth fracture

(Summit, Robbins, Hilton, & Schwartz, 2006) .

Material Consideration:

This design ensures the adaptation of composite to cavity because of bea ding property of material

and avoids void formation in margins, which can lead to recurrent caries.




Rounded internal line angles




How to do that:

By using proper parallel-sided bur with round profile, internal line angles would be rounded. During

refining with hand instrument, we should be careful not to create sharp angles.




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DENT 430, eportfolio Assignement #2, Class III Composite prep/resto, J. Ghahremani




8. No Iatrogenic Flaw:
Tooth considerations:
Unnecessary tooth removal during preparation increase the risk of pulpal involvement and

decrease strength and resistance of tooth to occlusal forces. In addition, damage to adjacent teeth

has been shown to increase possibility of caries on that region by producing a rough surface and

removing fluoride-rich and caries resistant surface layer (Qvist, V., Johannssen, L., & Vrunn, M.

1992).

How to do that:

By using a metal matrix in the proximal contact during preparation and careful use of instruments.


     From Proximal View

1. Parallel Incisal and gingival floors:
Tooth and material Consideration:
Same as mentioned in section 6.




           Parallel incisal and gingival floors




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DENT 430, eportfolio Assignement #2, Class III Composite prep/resto, J. Ghahremani




2. Curved labial wall:

Tooth and material consideration:

Extension of labial wall should be minimal for esthetic reasons but if caries dictates and we need to

extend the labial surface, it is a good idea to round the preparation instead of having it square that

will produce more esthetic results, as the eye will follow the line instead of stopping on it (Gardner,

K. 2008).




                                 Curved labial wall




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DENT 430, eportfolio Assignement #2, Class III Composite prep/resto, J. Ghahremani




                                  Restoration




1. Properly cured composite:

Tooth and material consideration:

All of the mechanical, physical and clinical properties of composite restorations depend on proper

polymerization of material (Powers , J.M., Sakaguchi, R.L, 2006). This criterion is measured by the

term of Degree of conversion (DC). The DC is a measure of the percentage of carbon-carbon double

bonds that have been converted to single bonds to form a polymeric resin. The higher the DC, the

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DENT 430, eportfolio Assignement #2, Class III Composite prep/resto, J. Ghahremani




better the strength, wear resistance, and many other properties essential to resin performance

(Anusavice, 2003). In the tacky surface layer of improper cured composite, number of unreacted

carbon double bonds may be as high as 75% which can cause all of above consequences (Powers ,

J.M., Sakaguchi, R.L, 2006). Therefore, proper curing of composite is a crucial part in this kind of

restorative procedure.

How to do that:

By using thin layers of composite before curing to ensure complete polymerization and proper

application of curing light (type, duration, distance).

2. Free of voids:

Tooth and material consideration:

Presence of void in composite restorations may be due to improper application of composite, sharp

internal line angles or contamination of cavity during restoration. Each of these condi tions could

lead to failure of the restoration as the result of marginal leakage and recurrent caries.

How to do that:

All of three above factors should be considered to prevent void formation in the bulk or margins of

the restoration. Other common factor to create void is “playing” with composite for long time

especially under the head light that can partially polymerize composite and make void in the bulk

of restoration.




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DENT 430, eportfolio Assignement #2, Class III Composite prep/resto, J. Ghahremani




3. Homogeneous and translucent esthetic appearance:

Tooth and material Consideration:

Greater translucency improves vitality in the final shade; smoother surface texture provides a

glossy surface with light reflective patterns similar to enamel (Powers , J.M., Sakaguchi, R.L, 2006).

Any heterogeneity in composite will influence the appearance of restoration and it may indicate

the improper polymerization of the material. These imperfections may lead to crack or even

fracture of composite in future.

How to do that:
By proper selection and handling of composite to avoid entrapment of air in the bulk or creating

any flaws or cracks during handling or curing of composite and by preventing undesirable

polymerization of composite by head light during working with material.

4. Smooth, No visible scratches:
Tooth and material Consideration:
Scratched or unfinished composite restoration may lead to staining in surface of restoration, faster

wear, more marginal leakage and unpleasant feeling by the patient. Optimum finishing and

polishing of composite resins is a very important step in the completion of the restoration. Residual

surface roughness can encourage bacterial growth, which can lead to a myriad of problems

including secondary caries, gingival inflammation, and surface staining (Anusavice, 2003).

Consequently, trying to achieve the smoothest polished surface of composite, which is similar to

the adjacent tooth structure, provides desirable restoration and ensures better clinical service to

the patient.
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DENT 430, eportfolio Assignement #2, Class III Composite prep/resto, J. Ghahremani




How to do that:

The smoothest surface on a restoration can be obtained by curing the composite against a smooth

matrix strip. This minimizes porosities as well as the oxygen-inhibited layer. However, it is often

difficult to achieve proper contours and margin adaptation without some amount of finishing

(Anusavice, 2003). For finishing, it is better to use hand instruments to remove flash especially on

proximal surface and cleoid-discoid carver for lingual. Finishing burs are also suitable for gross

finishing but care must be taken to avoid touching sound tooth surface. Polishing can be done by

polishing systems such as ENHANCE and for the final glossy appearance we can use polishing

pastes.

5. Original contour is restored:

Tooth and material Consideration:

Correct contouring of anterior composite restoration provides proper occlusion and esthetic,

preserves periodontal health and reduces the risk of recurrent caries.




               Convex proximal contour                                        Properly shaped marginal ridge



          No overhand or proximal flash                                       No lingual flash




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DENT 430, eportfolio Assignement #2, Class III Composite prep/resto, J. Ghahremani




How to do that:

Most of the contouring should be done before curing by proper application of matrix and forming

the composite with hand instruments (Felt 6 composite PPI). After polymerization for adjusting the

final contour, hand instruments and finishing burs are effective. Creating a properly shaped

marginal ridge and lingual fossa, convex proximal surface and avoiding proximal overhangs are the

criteria.


6. Positive contact:

Tooth and material consideration:

Passive proximal contacts may lead to food impaction and periodontal problems, recurrent caries,

tooth migration and unpleasant appearance (Newman, M.G, Takei, H.H 2006). For this reason,

proximal contacts should be formed properly to preserve health of the tooth and its supporting

structures.




               Positive contact




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DENT 430, eportfolio Assignement #2, Class III Composite prep/resto, J. Ghahremani




How to do that:

In conservative preparations, preserving tooth structure in contact area will help to create a

positive contact. In more extended preparations, pre wedging will help to compensate the

thickness of matrix and creates a more positive contact ( Roberson, Heymann, & Swift 2006). During

proximal finishing and polishing, operator must be careful in working with polishing strips

otherwise contact area could be easily opened.




7. Esthetic results:

Tooth and material Consideration:

Esthetic is the prime concern in anterior restorations. To ensure an optimal esthetic result, certain

basic artistic elements must be considered (Roberson, Heymann, & Swift 2006). These elements

include the following:

        Shape or form

        Symmetry and proportionality

        Position and alignment

        Surface texture

        Color

        Translucency




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DENT 430, eportfolio Assignement #2, Class III Composite prep/resto, J. Ghahremani




How to do that:

Meticulous attention to every detail of preparation, composite selection, composite application,

finishing and polishing is crucial to achieve an esthetically accepted restoration.


1. Where did I have the most problems? What did I do to solve these problems?

Following all of these criteria (confining to marginal ridge, parallelism, butt-joint cavosurface, mid-

contact point …) in such a small cavity was a real challenge. To achieve an acceptable result, correct

selection and proper application of instruments and materials are MUCH more important than in a

bigger cavity.


2. How will this help you in defining yourself as a dentist?

I found that having good dexterity and proper control of cutting instruments are critical “arts” that

a dentist should learn.




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DENT 430, eportfolio Assignement #2, Class III Composite prep/resto, J. Ghahremani




                                            References:

     1. Anusavice, K. (2003) Dental Materials. St. Louis: Saunders.

     2. Ash, M., Nelson, S. (2002) Wheeler's Dental Anatomy, Physiology and Occlusion. Saunders

        Pub Co

     3. Gardner, K. (2008). Dent 430 Class III composite preparation. UBC, Faculty of dentistry.

     4. Grippo , J.O., Simring, M., Schreiner, S.(2004) Attrition, abrasion, corrosion and abfraction

        revisited A new perspective on tooth surface lesions. J Am Dent Assoc, Vol 135, No 8, 1109-

        1118

     5. Newman, M.G, Takei, H.H (2006): Carranza’s Clinical Periodontology. Saunders Pub Co

     6. Powers , J.M., Sakaguchi, R.L (2006): Craig’s Restorative Dental Material. St. Louis: Mosby.

     7. Qvist, V., Johannssen, L., & Vrunn, M. (1992) Progression of approximal caries in relation to

        iatrogenic preparation damage. Journal of Dental Research. 71: 1370-1373.

     8. Roberson, T. M., Heymann, H. O., & Swift, E. J. (Ed). (2006). Sturdevant’s Art and Science of

        Operative Dentistry. St. Louis: Mosby.

     9. Summitt, J. B., Robbins, J. W., Hilton, T. J., Schwarz, R. S. (2006). Fundamentals of Operative

        Dentistry: A contemporary approach. Chicago: Quintessence Publishing Co, Inc




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