Material Selection: A Case Report

Restorative material selection poses one of the most common dilemmas facing clinicians. With the myriad of available products, which one is the most appropriate for our patients’ needs? Should it be stacked, pressed, or substrate-supported porcelain? Should it be a metal, or a direct or indirect composite?

In terms of porcelain, there are a multitude of materials from which to choose. They all have subtle and sometimes dramatic differences. Knowing the specifications of each porcelain system as well as the clinical demands of the patient would greatly assist the clinician in making the appropriate choice. This article reviews this choice process and treatment procedures for a specific clinical case.

CASE REPORT

This 46-year-old female patient presented with several concerns revolving around improving her smile. As a beautician, she constantly worked around people. She knew that a contributing factor to her success was to have an attractive smile. “Having studied Dale Carnegie, she was aware that a smile can indeed win friends and influence people.¹” The patients most obvious defect was the 3-mm diastema between teeth Nos. 8 and 9 (Figure 1). This space creates an involvement with the optical physiological principle of “duality.” The human eye cannot focus on 2 objects of similar size and appearance that are close to each other. This is an unresolved situation, because the eye will jump back and forth, not knowing which one to focus on. This is the reason why diastemas are objectionable to many people. If the 2 similar objects are placed in contact with one another or made a different color, this condition is resolved.

Figure 1. Diastema and negative corridor.	Figure 2. Floss used to align the zeniths.

The patient also presented with a negative corridor in her aesthetic zone (Figure 1).  Her premolars were positioned slightly lingual to her canines. This caused dark or recessed areas on either side of her smile. The final area of correction involved the gingival zenith above tooth No. 10. Excessive gingival tissue covered 3 mm of her clinical crown (Figure 2).

As is the situation with many aesthetic cases, the mandibular teeth were not to be restored. This could lead to long-term antagonistic activity between maxillary porcelain and mandibular enamel.² This particular problem can be related directly to the leucite component of the fired porcelain. Leucite, which is a product of the sintering process, is a relatively hard crystalline material possessing sharp edges. Recently, several porcelains have been marketed that do not possess this undesirable property. By fusing the material at considerably lower temperatures, the leucite component does not form. Should it be present, though, the size and amount of the crystal are not sufficient to create the unwanted characteristics so common in dental porcelains. In this case, the selection of a low-wear, less antagonistic porcelain was essential.

MATERIAL SELECTION

Softspar (Pentron) was selected as the restorative porcelain for this case for several reasons.³ With 9 levels of opacification along with a wide range of specialty powders and modifiers, Softspar provides an excellent match to natural tooth shades. The formulation of Softspar is the reason for a consistency of properties. When feldspar is mined,  there are variations present in deposits. By adding 50% synthetic feldspar to 50% mined feldspar, a more consistent porcelain is achieved.

Moving away from the anterior teeth into the premolar and molar areas, the decision to utilize a stronger material was addressed. The fact that 9 times more force can be placed on molars than incisors aided in the decision to utilize a stronger material in the premolar area. In this region of the mouth, OPC (Pentron) was the choice due to its increased strength and optical properties similar to Softspar.

Figure 3. Anterior 6 Softspar restorations. Premolar OPC restorations.

Ten teeth were to be treated: 6 teeth were indicated for full porcelain coverage and the 4 premolars were treatment-planned for onlay veneers (Figure 3).

Clinical Procedure

Figure 4. Electrosurgery to correct gingival zenith.

After shade selection, the first area of correction was the irregular gingival zenith (Figure 2). Floss was utilized to aid in visualization of the proper gingival zenith above tooth No. 10 (Figure 2). Probing revealed that this redundant tissue could be removed without involvement of the biologic width. This tissue was removed utilizing the Macan MC6 electrosurgical unit (Figure 4).

Figure 5. Rubber dam isolation for preparation.	Figure 6. All old restorative material removed.
Figure 7. Renamel hybrid buildups.	Figure 8. Occlusal plane established. Interpupillary line and incisal edge.

Next, a rubber dam was placed, and the 6 anterior teeth were prepared for full porcelain crowns (Figure 5). All defective restorations were removed and replaced with Renamel hybrid (Cosmedent, Figures 6 and 7). (Prior to treatment it was determined that this patients interpupillary line was to be utilized as being parallel to the occlusal plane.) After completion of the 6 anterior preparations,  the patient was asked to stand and remove her safety glasses. This allows the clinician to alter the incisal edges of all the preparations to create a line parallel to the interpupillary line (Figure 8). This will give the laboratory technician an exact reference to the occlusal plane.

Figure 9. Onlay veneer preparation.

Next, all 4 premolars were prepared to receive onlay veneers (Figure 9). This restoration allows us to replace any defective filling material, conserve the functional lingual cusp, and build out the facial aspect of the tooth to correct the negative corridor. All sharp edges as well as margins were polished with Brasselers 0875009 diamond. Finally, the coronal one third of each preparation was polished to a high shine with the Shofu One Step polishing point.

Figure 10. RSVP stint in place.

Figure 11. Light-body composite in tray.

Figure 12. Completed temporization.

Final impressions were taken with Aquasil Monophase (DENTSPLY). An occlusal rec-ord was taken utilizing Futar occlusal bite registration material (Kettenbach). The RSVP technique (Cosmedent) was utilized to fabricate all temporaries. This material allows us to obtain an exact duplication of all functional areas as well as the best control of margins and soft tissue (Figures 10 to 12).

Much information is given to the laboratory technician to assist in achieving the desired results. Photographs were taken of the shade tabs and preparations before and after with temporaries in place, and straight-on and side-view photographs were taken to demonstrate full, soft-tissue contours.

Figure 13. Models in centric relation with laboratory wax-up.	Figure 14. All restorations complete.

The exact diagnostic wax-up on a Sam III articulator (Great Lakes Orthodontics) mounted in centric relation was given to the technician as a guide (Figure 13). In this case the laboratory technician first waxed the premolars and cast them in OPC (Figure 14).

Figure 15. Seated restorations.

After that, the 6 anterior teeth were created with Softspar utilizing the classic stacked or layering technique to produce incisal translucency (Figure 3). These lifelike restorations made out of the 2 materials created a pleasing, bright smile that solved the patient’s aesthetic problems (Figures 3, 14, and 15).

The restorations were tried-in and accepted by the patient. Calibra (DENTSPLY) was used to bond these restorations to place. The 6 Softspar restorations were inserted first, followed by placing the OPC restorations one side at a time. By placing these in sequence, there was a maximum of working time and control of soft tissue. Excess cement was removed, and all margins were polished. The polishing protocol included the following:

(1) Brasseler:

• No. 30 grit diamond 379F-31-023 135F-31-014

• No. 15 grit diamond 135EF-31-014 379EF-31-023

• No. 30 bladed finishing bur H379UF-023 H135UF-014

(2) Shofu:

• no stripe polishing point

• yellow stripe polishing point

• white stripe polishing point

(3) Other companies:

• CeriSaw by DenMat was used to open contacts.

• red stripe diamond strip by GC America

• entire series Epitex strips by GC America (blue, green, tan, gray)

Establishment of proper occlusal form followed. The final restorations were aesthetically pleasing and provided excellent occlusal form (Figure 15).

CONCLUSION

Figure 16. Lateral view of seated restorations.	Figure 17. Lateral view of restorations.

Although material selection can be a challenge, matching the aesthetic demands of the patient with the properties of materials can result in excellent clinical results. The challenge in the case described in this article was to select a low-wear material to function against natural teeth. In addition, we needed to have an aesthetically compatible material in the higher stress areas of the premolars. The selected materials worked well in this situation. There is no difference in appearance of these 2 materials when placed adjacent to each other (Figures 16 and 17), although there is a significant difference in strength between pressed porcelain and stacked porcelain.

Figure 18. Anterior view with all restorations in place.

Figure 19. Smile view with all restorations in place.

Figure 20. Before-and-after picture, showing corrections of aesthetic deficit.

Acknowledgement

References

1. Carnegie D. How to Win Friends and Influence People. New York, NY: Simon & Shuster; 1981.

2. Wynne WPD. Terminal wear syndrome. Contemp Esthet Restorative Pract. 1999;3:52-54.

3. Suzuki S. Simulated enamel wear during occlusal contact. Am J Dent. 2004;17[5]: 373-377.

Dr. Wynne maintains a private practice in Raleigh, NC, focusing on aesthetic and restorative dentistry. He graduated from the University of North Carolina School of Dentistry in 1971 and has recently achieved the status of Pankey Scholar. He is a member of the American Academy of Cosmetic Dentistry and a long-time member of the American Academy of Dental Practice Administration. He has completed Level I and II of the Ultimate Esthetic Continuum at Americus in New York City, and his past lecturing has been with the Ultimate Esthetic Continuum in New York City, the Esthetic Epitome in Charlotte, NC, and various educational study groups. He has published numerous articles on aesthetic dentistry, occlusion, and eating disorders. He can be reached at (919) 851-3716.

Dr. Leinfelder, a native of Wisconsin, earned his DDS and MSc (dental materials) degrees from Marquette University. After serving for 8 years on the faculty at Marquette, he joined the faculty at the University of North Carolina School of Dentistry, where he attained the rank of professor and director of biomaterials clinical research in the Dental Research Center. In 1983, he joined the School of Dentistry at the University of Alabama and is the recipient of the Joseph Volker Chair. He also served as chairman of the department of biomaterials until 1994. Presently he holds positions at both universities: adjunct professor at University of North Carolina and professor emeritus at the University of Alabama. He has served as associate editor of the Journal of the American Dental Association and is a dental materials research consultant for numerous materials companies. He has published more than 225 papers on restorative materials, authored more than 150 scientific presentations and a textbook on restorative materials and techniques, and has lectured nationally and internationally on clinical biomaterials. He can be reached at kcullie@aol.com.