Alex ChenComposite Class III preparation & restoration

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Composite Class III Preparation & Restoration

Alex ChenDent 430 ePortfolioFaculty of Dentistry

University of British Columbia

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Alex ChenComposite Class III preparation & restoration

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Composite Class III Preparation critical requirements

Critical requirement

s of this procedure

Rationale of requirements and supporting literature

New skills accomplished in this excercise, problems encountered, and breakthrough

moments

Did my product meet

these requirement

90 degrees to the cavosurface

1. This requirement ensures all the unsupported enamel is removed since enamel rods orient perpendicular to cavosurface (Schwartz et al., 2006).

2. This is also important for the resistance form of the composite restoration as it improves structural integrity to prevent fracture (O’Brien, 2006).

For me, the key to meeting this requirement is to always make sure the bur is 90o to surface before drilling. I ensure this by checking the bur angulation is 90o in my mirror both mesial-distally and facial-lingually before starting.

Yes

Incisal extension to the mid-contact

1. By preserving some natural contact, it becomes easier to for the restoration to have a closed contact since the contact does not need to be made entirely by composite (Roberson et al., 2006).

2. Just gingival to the contact point is a common location for caries to occur, hence, we need to extend our preparation there for caries removal (Schwartz et al., 2006).

To meet this requirement, I would mark the end-points of the preparation on the tooth with pencil before I start. This way, my preparation would always have the correct extension. As my skills improve, I can now match my actual preparation to my pre-operatory drawing without any visual aids.

Yes

Gingival extension just beyond caries

1. The disease dictates the outline form of the preparation. The preparation need to extend just beyond the caries to ensure proper caries removal (Gardner, 2009).

2. Also extending preparation just beyond caries preserves the maximum amount of health enamel and

I made sure my preparation is as conservative as possible by taking off carious tooth structure in small increments.

Yes

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Alex ChenComposite Class III preparation & restoration

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dentin (Schwartz et al., 2006).Does not cross the marginal ridge

Extending the preparation past the marginal ridge significantly weakens the tooth structure (Qualtrough et al., 2005).

This is the hardest requirement to meet for me, especially on the lateral incisors where the marginal ridges are so thin. The width of the marginal ridge is sometimes smaller than the diameter of my bur. My breakthrough moment came when I realized I should start the preparation gingivally where there’s more space from the adjacent tooth. Also, I should start with a portion of the bur in the gingival embrasure space for the teeth that have marginal ridges with width equal to or smaller than the diameter of my bur.

Yes

Axial lingual wall parallel to the proximal cavosurface

1. The parallelism contributes to resistance form of the restoration by minimizing the displacement forces under functional stress (Roberson et al. 2006).

2. The parallelism ensures the preparation has even distance to the pulp, and hence decrease the chance of pulp exposure (Robertson et al., 2006).

I achieved this by frequently checking my preparation lingually in my hand-mirror. Finally, the parallelism can be made even more accurate by hand-instrumenting.

No

Incisal and gingival floors are parallel

The parallelism contributes to resistance form by minimizing displacement forces (Schwartz et al. 2006).

Same as above. Yes

Rounded internal form

1. A rounded internal form eliminates any stress points for the restoration, which may fracture under stress (Feilzer et al., 1998).

2. A sharp internal form may be hard for composite to flow in and fill all spaces, and a void may result (Schwartz et al. 2006).

This requirement is achieved by modifying the preparation with hand-instruments as the final step.

Yes

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Composite Class III Preparation pictures

Composite Class III Preparation discussion

In achieving this break-throughs, how will this help you in defining yourself as a dentist?

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90 degrees to cavosurface.

Axial lingual wall parallel to the proximal cavosurface (requirement not met)

Incisal extension to mid-contact.

Rounded internal form Does not cross the marginal ridge

Incisal and gingival floors are parallel

Alex ChenComposite Class III preparation & restoration

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While learning about the class III preparations, we were asked if we should bevel the proximal cavosurface similar to a class II preparation. I looked at literatures for this and found papers supporting both methods. It seems beveling was supported in older sources and teachings while the standard now is not to bevel. I think not beveling makes a lot of sense because due to extension into buccal enamel, the class III preparation exposes much more enamel surface areas than class II. Exposing a little bit more enamel rods with beveling in class III preparation will not significantly improve retention, but it will create an area of thin resin that’s susceptible to fracturing. Realizing this was my biggest breakthrough in class III preparation.

In achieving this break-through, I find that there are many ways of accomplishing a task. As dentists, we should not blindly follow a single method we were taught as we need to be able to justify everything we do. With advances in research, I have no doubt that a lot of things we learned in dental school will be out-dated by the time we retire. The beveling of class III preparation is a good example of this. It would therefore be very important for dentists to be open to changes and not practice the same way throughout his or her career.

Composite Class III Restoration critical requirements

Critical requirements

of this

Purpose of critical requirements and supporting literature

New skills accomplished in this excercise, problems encountered, and breakthrough

moments

Did my product

meet

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Alex ChenComposite Class III preparation & restoration

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procedure requirementProperly cured- hard to the touch

The degree of polymerization of the composite monomers is related to its mechanical properties. A compromised composite due to lack of curing results in a less polymerized and weaker restoration that would likely fracture under minimal force (Sakaguchi et al., 1992).

I achieve this by adding the composite in small increments, which ensures that each layer would be properly cured.

Yes

Buccal and Lingual Cusps in proper alignment

Does not apply to this restoration Does not apply to this restoration N/A

Homogeneous and translucent esthetic appearance

The restoration needs to match the color of natural teeth to give the patient a pleasing look and improve patient satisfaction. Esthetics also has great impact on a person’s self-esteem and self-image. This is the main reason why composite the most commonly used for the anterior teeth where esthetics is important (Okuda, 2005).

After finishing the restoration, I would polish the surface with enhance kit. My breakthrough is to run the enhance kit at very low speeds (usually 20-30% power). This makes the surface homogeneous and smooth while not flattening the surface at the same time.

Yes

Smooth, no visible scratches

1. Scratches on restoration may feel unpleasant to the patient.

2. It also provides a place for bacteria accumulation and growth. (Roberson et al., 2006).

3. Lastly, scratches may act as centers for corrosion (Akerboom et al., 2006).

I achieved this by slightly overfilling my preparation and contouring it with composite finishing burs. Finally, I would polish it as described above.

Yes

Original Contour is

1. Improper contouring in the form of overhangs leads to increased chance of plaque accumulation and

My breakthrough in achieving this requirement is learning to adapt the correctly

Yes

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restored may lead to recurrent caries or periodontal diseases. (Thomas et al., 2007)

2. Proper contouring gives the restoration an esthetic appearance. (Okuda, 2005)

shaped finishing bur to the surface to be contoured. No one bur will work on all surfaces. For example, I would use the football bur on lingual surfaces of anterior teeth because it follows the natural concavity of the lingual fossa.

No iatrogenic flaws

1. Unnecessary removal of sound tooth structure should always be avoided (Gardner, 2009).

2. Iatrogenic flaws increase chances of caries developing (Qvist et al., 1991).

This is the most difficult requirement for me. Trying to avoid the adjacent tooth may make me remove too much of the marginal ridge. Meeting this criteria requires a very steady hand and stable fulcrum so I can comfortably get as close as possible to the adjacent tooth without accidentally cutting it with my bur.

Yes

Positive contact

1. Prevent food impaction.

2. Maintaining health of interproximal soft tissue (Roberson et al., 2006).

3. Prevent tooth migration (Mamoun and Ahmed, 2006).

My breakthrough for this requirement is to fill the composite in small increments and not pulling the matrix too tight while curing the composite. By not pulling the matrix too tight, there would be more composite bulk interproximally to close the contact. The negative side of holding the matrix loosely is composite may not adapt to the contour of the tooth. This problem is avoid by loading the composite in very small increments so that there’s only minimal flash and contour irregularites that can be easily fixed with finishing burs and proximal strips.

Note that this is a requirement that would lead to an automatic re-do if not met. I completely agree with this. I have an open-contact

Yes

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restoration in my own mouth and it bothers me greatly having to floss out food debris every time I eat.

No marginal voids

Same as above, marginal voids or overhangs accumulates food debris and plaque. This may lead to recurrent caries. Depending on location, marginal void could also make the restoration susceptible to fracture.(Gardner, 2009)

My breakthrough is realizing my marginal voids are the result of loading the composite in increments that are too large. I tend to do this when I’m rushed to finish a restoration in limited time. However, the plan often backfires since it is harder to flow the larger composite increment to fill all voids and I would end up with marginal voids that takes a long time to fix.

Another breakthrough moment I had is realizing a dirty composite PPI can also cause marginal voids because the composite would stick to the PPI and be pulled away from the preparation when I withdraw the PPI before curing. So now, I virtually eliminated any marginal voids by loading my composite in small increments and making sure my composite PPI is always clean.

Yes

Composite Class III Preparation pictures

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Alex ChenComposite Class III preparation & restoration

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Composite Class III Restoration discussion

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Original Contour is restored

Positive contact Smooth, no visible scratches

No iatrogenic flaws

Homogeneous and translucent esthetic appearance

No marginal voids

Alex ChenComposite Class III preparation & restoration

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In achieving this break-through, how will this help you in defining yourself as a dentist?

My biggest problem with class III restoration is closing the contact. My breakthrough was realizing that the contact can be closed by not holding the matrix band too tight. This would close the contact but it also lead to excess resin in the interproximal area. The key in solving this is to load the composite in small increments so that the last increment only leaves minimal composite that’s very easy to clean off.

With this break-through, I find it is very important for dentists to be patient. For example, cutting corners by loading composite in large chunks would leave too much excess composite at the interproximal area which will take huge effort and time to clean up. Hence, being patient and not taking short-cuts will not only produce higher quality work, it will save the dentist time as well.

References:Feilzer, J., DeGee, J., Davidson, L. (1998). Setting stress in composite resin in relation to configuration of the restoration. Journal of

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Alex ChenComposite Class III preparation & restoration

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Dental Research, 66(11): 1636-1639.

Gardner, K. (2009). Dent 430 Operative Dentistry 2009–2010 Module Manual. Vancouver: UBC.

Gardner, K., Class III Composite Preparation and Restoration PowerPoint. Vancouver BC. Retrieved October 26, 2009, from https://www.vista.ubc.ca/webct/urw/lc5116011.tp0/cobaltMainFrame.dowebct

Mamoun, J., Ahmed, M. (2006). Matrix for Class III and Class V preparations connected at the proximal box. Journal of American Dental Association, 137(2): 186-189

O’Brien, W. J. (2002). Dental materials and their selection. Chicago, Illinois: Quintessence Publishing Co.

Okuda, W. (2005). Achieving optimal aesthetics for direct and indirect restorations with microhybrid composite resins. Journal of Practical Procedures & Aesthetic Dentistry,17(3): 177-184.

Qualtrough, A., Satterthwaite, J., Morrow, L. (2005). Principles of operative dentistry. Ames, Iowa: Blackwell Pub.

Qvist, V., Johanessen, L., & Bruun, M. (1991). Progression of approximal caries in relation to iatragenic preparation damage. Journal of Dental Research, 71(3): 1370-1373.

Roberson, T., Heymann, O., Swift, J. (2006). Studevant’s Art and Science of Operative Dentistry. St. Louis, Missouri: Mosby Pub.

Sakaguchi, R., Peters, C., Nelson, R., Douglas, H., Poort, W. (1992). Effects of polymerization contraction in composite restorations. Journal of Dentistry, 20(3): 178-182.

Schwartz, R., Summitt, J., Robbins, W. (2006) Fundamentals of operative dentistry : a contemporary approach (3rd ed.) Chicago : Quintessence Pub.

Thomas, R., Ruben, J., Ten-Bosch, J., Fidler, V., Huysmans, M. (2007). Approximal Secondary Caries Lesion Progression. Journal of Caries Research, 41(5): 399-405.

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