- Email: [email protected]
Longevity versus esthetics
PERSPECTIVES
O B S E R VAT I O N S
Longevity versus esthetics The great restorative debate everal decades ago, most restorative dentistry was oriented toward long-term service, and the appearance of the restorations was of secondary importance. Placement of three-quarter cast gold alloy crowns on both posterior and anterior teeth was common, and patients accepted these tooth restorations in spite of their unsightly appearance. Gold foil restorations were placed in anterior teeth, often showing significant gold display. Cast gold alloy and amalgam restorations were the foremost long-lasting restorations. Practitioners placed these metallic restorations knowing they were not esthetically pleasing to most patients, but justifiably expecting years of service from them. It is wellknown among practitioners that well-placed cast gold alloy restorations serve well for many years, and that amalgam similarly provides admirable service over a relatively long period.1-9
S
Significant variability in restoration longevity is reported in the literature.1-9 In the past, when long-lasting tooth-colored restorations were unavailable and restorations needed a toothlike appearance, it was necessary to place silicate cement or the early generations of resinbased composite on top of the metal substructures. These restorations lasted only a few years and never were highly acceptable from an esthetic standpoint. Eventually, new materials with better esthetic characteristics were developed and were incorporated into dental practices—slowly, in most cases. Today, it is obvious to the practicing profession that esthetic acceptability is the primary concern in the consideration of restorative options. Has the dominance of esthetics over long-term service gone too far? Should practitioners reemphasize and suggest to patients the known and previously dominant long-lasting
Gordon J. Christensen, DDS, MSD, PhD
metal restorations over the more natural-looking but potentially less long-lasting tooth-colored crowns, fixed prostheses and direct resin-based composites? This column provides my observations about esthetics versus service relative to dental restorations. Additionally, it makes suggestions about the desirability of informing patients about these alternatives to allow informed acceptance of treatment plans. IMPROVEMENTS IN ESTHETIC RESTORATIVE MATERIALS
In the mid-1980s, resin-based composite materials continued to be improved. Restorations made of these new materials containing smaller-particle fillers demonstrated less wear and lasted longer than similar restorations made from earlier materials. These relatively inexpensive, directly placed restorations soon became popular for use in small-to-moderate–sized tooth preparations, and some dentists shifted their preference for treatment away from amalgam to resin-based composite as their primary restora-
JADA, Vol. 138 http://jada.ada.org Copyright ©2007 American Dental Association. All rights reserved.
July 2007
1013
PERSPECTIVES
OBSERVATIONS
tive material for simple restorations. A relatively recent survey indicated that 68 percent of responding dentists used amalgam routinely, and the others had changed to using resin-based composite as their chosen direct restorative material for primary posterior teeth.10 Porcelain-fused-to-metal crowns and fixed prostheses, introduced in the early 1960s, soon became the most commonly used anterior crown restorations for moderately or severely broken-down teeth—and, amid controversy, many dentists started to use these materials for posterior tooth restorations. In 2006, one of the largest dental laboratories in the United States reported that porcelain-fused-to-metal restorations composed 61 percent of the crown restorations they provided to dentists, and full-metal crowns constituted only 7 percent of their production.11 This information probably is representative of current crown and fixed prosthesis use in the United States because of the diverse geographic clientele served by this large laboratory. Further information from the same laboratory showed that all-ceramic and resin-based composite crown use has continued to grow over the past decade. In 1997, 20 percent of the crowns it fabricated were all-ceramic or resin-based composite. In 2006, 32 percent were ceramic or polymer, and in the first quarter of 2007 alone, 32 percent of its crowns were in this category.11 I predict that this trend away from full-metal crowns toward all-ceramic crowns is not likely to be reversed. It has been my observation 1014
JADA, Vol. 138
that the newer zirconia-based all-ceramic crowns and fixed prostheses are performing successfully and are growing in use (G.J. Christensen, unpublished data, August 2002). Some brands of zirconia-based all-ceramic crowns are Cercon (Dentsply, York, Pa.), IPS e.max (Ivoclar Vivadent, Amherst, N.Y.), Everest (KaVo, Lake Zurich, Ill.) and Lava (3M ESPE, St Paul, Minn.). I predict that the use of all-ceramic crown and fixed prostheses will continue to grow until these restorations graduIt appears that in spite of the availability of metallic restorations of high quality and known longevity, many patients either are not informed about their availability or are informed and still refuse them.
ally equal and then replace porcelain-fused-to-metal restorations in terms of use. The publication of lay information about computer-directed milling of tooth-colored restorations provided to patients in a single appointment (CEREC, Sirona Dental Systems, Charlotte, N.C.) has been interesting to patients and has stimulated further patient motivation to request tooth-colored restorations. Overall, continuing improvements in dental materials and techniques and public education about the availability of these restorations has stimulated the movement away from metal restorations. One significant point that usually is omitted in lay articles about the availability of toothcolored restorations is the
reduced longevity of these restorations in relation to the longproven metal restorations.1-9 DISPLAY OF METAL RESTORATIONS: THE CHANGE IN PUBLIC OPINION
It is clear to restorative dentists that most patients will not accept the placement of metal restorations in areas of the mouth that are visible when they smile. This change probably has been stimulated by several occurrences. Widely viewed lay television programs showing dramatic esthetic improvements in patient smiles effected by tooth-colored restorations has made the public aware that display of metal dental work is not necessary. Many articles in lay magazines emphasize the bleaching of teeth, the removal of metal restorations, the placement of tooth veneers made of ceramic or polymer, and the placement of tooth-colored crowns and fixed prostheses. The public reads these articles, sees the television presentations and requests the tooth-colored restorations from dentists, and practitioners feel obligated to provide the tooth-colored restorations. The result is the slow but observable reduction in use of metal restorations. It appears that in spite of the availability of metallic restorations of high quality and known longevity, many patients either are not informed about their availability or are informed and still refuse them. ALLEGED HEALTH CHALLENGES RELATED TO METAL RESTORATIONS
Public health organizations continue to support use of amalgam as a dental restoration and deny the presence of significant nega-
http://jada.ada.org July 2007 Copyright ©2007 American Dental Association. All rights reserved.
PERSPECTIVES
tive health influences related to its use. However, the lay literature and the Internet include many publications promoting alleged negative health changes related to placement of metal restorations in the mouth. In spite of the preponderance of scientific evidence supporting metal’s use in the mouth, many laypeople elect to believe the articles on the alleged ill effects of metal restorations. The confusion that exists on this subject possibly has stimulated the increased use of nonmetal restorations. DENTISTS’ PREFERENCES
For several years, I have had the opportunity to conduct a practice that is composed primarily of dentists as patients. It has interested me to observe that most of these dentists prefer to have cast gold restorations instead of all-ceramic or porcelain-fused-to-metal restorations when the needed restorations are in nonesthetically compromising locations. In a written questionnaire survey of the American Academy of Esthetic Dentistry that I conducted in 2002, the majority of the members and guests of that Academy—in spite of the name of their organization and their interest in esthetic dentistry—indicated that they preferred full cast-gold restorations on their own maxillary and mandibular second molars (G.J. Christensen, unpublished data, August 2002). They preferred metal occlusal
surfaces with ceramic facings on maxillary and mandibular first molars. Only in the instance of premolars requiring crowns did these dentists prefer all-ceramic or porcelain-fused-to-metal restorations without metal display. Judging by these observations, I can conclude that some dentists promote and carry out the placement of tooth-colored restorations in their patients, but that many of them prefer gold alloy restorations in some locations in their own mouths. INFORMING PATIENTS ABOUT METAL VERSUS TOOTH-COLORED RESTORATIONS
I suggest that when planning treatment for patients who need either direct or indirect restorations, the dentist should advise them that metal restorations are available, and that they usually provide longer service than most tooth-colored restorations.1-9 It has been my experience that some patients still prefer the tooth-colored restorations. I feel that their decision should be honored. However, in my opinion, not informing patients about the availability of placing metal in nonvisible oral locations, and about the potential longevity differences among the various tooth restorations, is not advisable. SUMMARY
The rapid trend toward toothcolored restorations and away from metal restorations is evident to all restorative dentists.
OBSERVATIONS
This column suggests some of the reasons for this change. Patients should be advised of the availability of metal restorations for nonvisible locations in the mouth and the expected longevity differences between metal and nonmetal restorations. ■ Dr. Christensen is the director, Practical Clinical Courses, and co-founder and senior consultant, CRA Foundation, Provo, Utah. He also is the dean, Scottsdale Center for Dentistry, Ariz. Address reprint requests to Dr. Christensen at CRA Foundation, 3707 N. Canyon Road, Suite 3D, Provo, Utah 84604. The views expressed are those of the author and do not necessarily reflect the opinions or official policies of the American Dental Association. 1. Opdam NJ, Bronkhorst EM, Roeters JM, Loomans BA. A retrospective clinical study on longevity of posterior composite and amalgam restorations. Dent Mater 2007;23(1):2-8. 2. Osborne JW. Amalgam: dead or alive? Dent Update 2006;33(2):94-8. 3. Van Nieuwenhuysen JP, D’Hoore W, Carvalho J, Qvist V. Long-term evaluation of extensive restorations in permanent teeth. J Dent 2003;31(6):395-405. 4. Donovan T, Simonsen RJ, Guertin G, Tucker RV. Retrospective clinical evaluation of 1,314 cast gold restorations in service from 1 to 52 years. J Esthet Restor Dent 2004;16(3): 194-204. 5. Stoll R, Sieweke M, Pieper K, Stachniss V, Schulte A. Longevity of cast gold inlays and partial crowns: a retrospective study at a dental school clinic. Clin Oral Investig 1999;3(2):100-4. 6. Mjor IA, Medina JE. Reasons for placement, replacement, and age of gold restorations in selected practices. Oper Dent 1993; 18(3):82-7. 7. Walton J, Gardner F, Agar J. A survey of crown and fixed partial denture failures: length of service and reasons for replacement. J Prosthet Dent 1986;56(4):416-21. 8. Libby G, Arcuri M, LaVelle W, Hebl L. Longevity of fixed partial dentures. J Prosthet Dent 1997;78(2):127-31. 9. Valderhaug J. A 15-year clinical evaluation of fixed prostheses. Acta Odontol Scand 1991;49(1):35-40. 10. Clinical Research Associates. Special report: product use survey 2005. CRA Newsletter 2005;29(10):3. 11. CRA Foundation. Zirconia vs. porcelainfused-to-metal (PFM): clinical performance at 1 year. CRA Newsletter 2006;30(11):1-4.
JADA, Vol. 138 http://jada.ada.org Copyright ©2007 American Dental Association. All rights reserved.
July 2007
1015
O B S E R VAT I O N S
Longevity versus esthetics The great restorative debate everal decades ago, most restorative dentistry was oriented toward long-term service, and the appearance of the restorations was of secondary importance. Placement of three-quarter cast gold alloy crowns on both posterior and anterior teeth was common, and patients accepted these tooth restorations in spite of their unsightly appearance. Gold foil restorations were placed in anterior teeth, often showing significant gold display. Cast gold alloy and amalgam restorations were the foremost long-lasting restorations. Practitioners placed these metallic restorations knowing they were not esthetically pleasing to most patients, but justifiably expecting years of service from them. It is wellknown among practitioners that well-placed cast gold alloy restorations serve well for many years, and that amalgam similarly provides admirable service over a relatively long period.1-9
S
Significant variability in restoration longevity is reported in the literature.1-9 In the past, when long-lasting tooth-colored restorations were unavailable and restorations needed a toothlike appearance, it was necessary to place silicate cement or the early generations of resinbased composite on top of the metal substructures. These restorations lasted only a few years and never were highly acceptable from an esthetic standpoint. Eventually, new materials with better esthetic characteristics were developed and were incorporated into dental practices—slowly, in most cases. Today, it is obvious to the practicing profession that esthetic acceptability is the primary concern in the consideration of restorative options. Has the dominance of esthetics over long-term service gone too far? Should practitioners reemphasize and suggest to patients the known and previously dominant long-lasting
Gordon J. Christensen, DDS, MSD, PhD
metal restorations over the more natural-looking but potentially less long-lasting tooth-colored crowns, fixed prostheses and direct resin-based composites? This column provides my observations about esthetics versus service relative to dental restorations. Additionally, it makes suggestions about the desirability of informing patients about these alternatives to allow informed acceptance of treatment plans. IMPROVEMENTS IN ESTHETIC RESTORATIVE MATERIALS
In the mid-1980s, resin-based composite materials continued to be improved. Restorations made of these new materials containing smaller-particle fillers demonstrated less wear and lasted longer than similar restorations made from earlier materials. These relatively inexpensive, directly placed restorations soon became popular for use in small-to-moderate–sized tooth preparations, and some dentists shifted their preference for treatment away from amalgam to resin-based composite as their primary restora-
JADA, Vol. 138 http://jada.ada.org Copyright ©2007 American Dental Association. All rights reserved.
July 2007
1013
PERSPECTIVES
OBSERVATIONS
tive material for simple restorations. A relatively recent survey indicated that 68 percent of responding dentists used amalgam routinely, and the others had changed to using resin-based composite as their chosen direct restorative material for primary posterior teeth.10 Porcelain-fused-to-metal crowns and fixed prostheses, introduced in the early 1960s, soon became the most commonly used anterior crown restorations for moderately or severely broken-down teeth—and, amid controversy, many dentists started to use these materials for posterior tooth restorations. In 2006, one of the largest dental laboratories in the United States reported that porcelain-fused-to-metal restorations composed 61 percent of the crown restorations they provided to dentists, and full-metal crowns constituted only 7 percent of their production.11 This information probably is representative of current crown and fixed prosthesis use in the United States because of the diverse geographic clientele served by this large laboratory. Further information from the same laboratory showed that all-ceramic and resin-based composite crown use has continued to grow over the past decade. In 1997, 20 percent of the crowns it fabricated were all-ceramic or resin-based composite. In 2006, 32 percent were ceramic or polymer, and in the first quarter of 2007 alone, 32 percent of its crowns were in this category.11 I predict that this trend away from full-metal crowns toward all-ceramic crowns is not likely to be reversed. It has been my observation 1014
JADA, Vol. 138
that the newer zirconia-based all-ceramic crowns and fixed prostheses are performing successfully and are growing in use (G.J. Christensen, unpublished data, August 2002). Some brands of zirconia-based all-ceramic crowns are Cercon (Dentsply, York, Pa.), IPS e.max (Ivoclar Vivadent, Amherst, N.Y.), Everest (KaVo, Lake Zurich, Ill.) and Lava (3M ESPE, St Paul, Minn.). I predict that the use of all-ceramic crown and fixed prostheses will continue to grow until these restorations graduIt appears that in spite of the availability of metallic restorations of high quality and known longevity, many patients either are not informed about their availability or are informed and still refuse them.
ally equal and then replace porcelain-fused-to-metal restorations in terms of use. The publication of lay information about computer-directed milling of tooth-colored restorations provided to patients in a single appointment (CEREC, Sirona Dental Systems, Charlotte, N.C.) has been interesting to patients and has stimulated further patient motivation to request tooth-colored restorations. Overall, continuing improvements in dental materials and techniques and public education about the availability of these restorations has stimulated the movement away from metal restorations. One significant point that usually is omitted in lay articles about the availability of toothcolored restorations is the
reduced longevity of these restorations in relation to the longproven metal restorations.1-9 DISPLAY OF METAL RESTORATIONS: THE CHANGE IN PUBLIC OPINION
It is clear to restorative dentists that most patients will not accept the placement of metal restorations in areas of the mouth that are visible when they smile. This change probably has been stimulated by several occurrences. Widely viewed lay television programs showing dramatic esthetic improvements in patient smiles effected by tooth-colored restorations has made the public aware that display of metal dental work is not necessary. Many articles in lay magazines emphasize the bleaching of teeth, the removal of metal restorations, the placement of tooth veneers made of ceramic or polymer, and the placement of tooth-colored crowns and fixed prostheses. The public reads these articles, sees the television presentations and requests the tooth-colored restorations from dentists, and practitioners feel obligated to provide the tooth-colored restorations. The result is the slow but observable reduction in use of metal restorations. It appears that in spite of the availability of metallic restorations of high quality and known longevity, many patients either are not informed about their availability or are informed and still refuse them. ALLEGED HEALTH CHALLENGES RELATED TO METAL RESTORATIONS
Public health organizations continue to support use of amalgam as a dental restoration and deny the presence of significant nega-
http://jada.ada.org July 2007 Copyright ©2007 American Dental Association. All rights reserved.
PERSPECTIVES
tive health influences related to its use. However, the lay literature and the Internet include many publications promoting alleged negative health changes related to placement of metal restorations in the mouth. In spite of the preponderance of scientific evidence supporting metal’s use in the mouth, many laypeople elect to believe the articles on the alleged ill effects of metal restorations. The confusion that exists on this subject possibly has stimulated the increased use of nonmetal restorations. DENTISTS’ PREFERENCES
For several years, I have had the opportunity to conduct a practice that is composed primarily of dentists as patients. It has interested me to observe that most of these dentists prefer to have cast gold restorations instead of all-ceramic or porcelain-fused-to-metal restorations when the needed restorations are in nonesthetically compromising locations. In a written questionnaire survey of the American Academy of Esthetic Dentistry that I conducted in 2002, the majority of the members and guests of that Academy—in spite of the name of their organization and their interest in esthetic dentistry—indicated that they preferred full cast-gold restorations on their own maxillary and mandibular second molars (G.J. Christensen, unpublished data, August 2002). They preferred metal occlusal
surfaces with ceramic facings on maxillary and mandibular first molars. Only in the instance of premolars requiring crowns did these dentists prefer all-ceramic or porcelain-fused-to-metal restorations without metal display. Judging by these observations, I can conclude that some dentists promote and carry out the placement of tooth-colored restorations in their patients, but that many of them prefer gold alloy restorations in some locations in their own mouths. INFORMING PATIENTS ABOUT METAL VERSUS TOOTH-COLORED RESTORATIONS
I suggest that when planning treatment for patients who need either direct or indirect restorations, the dentist should advise them that metal restorations are available, and that they usually provide longer service than most tooth-colored restorations.1-9 It has been my experience that some patients still prefer the tooth-colored restorations. I feel that their decision should be honored. However, in my opinion, not informing patients about the availability of placing metal in nonvisible oral locations, and about the potential longevity differences among the various tooth restorations, is not advisable. SUMMARY
The rapid trend toward toothcolored restorations and away from metal restorations is evident to all restorative dentists.
OBSERVATIONS
This column suggests some of the reasons for this change. Patients should be advised of the availability of metal restorations for nonvisible locations in the mouth and the expected longevity differences between metal and nonmetal restorations. ■ Dr. Christensen is the director, Practical Clinical Courses, and co-founder and senior consultant, CRA Foundation, Provo, Utah. He also is the dean, Scottsdale Center for Dentistry, Ariz. Address reprint requests to Dr. Christensen at CRA Foundation, 3707 N. Canyon Road, Suite 3D, Provo, Utah 84604. The views expressed are those of the author and do not necessarily reflect the opinions or official policies of the American Dental Association. 1. Opdam NJ, Bronkhorst EM, Roeters JM, Loomans BA. A retrospective clinical study on longevity of posterior composite and amalgam restorations. Dent Mater 2007;23(1):2-8. 2. Osborne JW. Amalgam: dead or alive? Dent Update 2006;33(2):94-8. 3. Van Nieuwenhuysen JP, D’Hoore W, Carvalho J, Qvist V. Long-term evaluation of extensive restorations in permanent teeth. J Dent 2003;31(6):395-405. 4. Donovan T, Simonsen RJ, Guertin G, Tucker RV. Retrospective clinical evaluation of 1,314 cast gold restorations in service from 1 to 52 years. J Esthet Restor Dent 2004;16(3): 194-204. 5. Stoll R, Sieweke M, Pieper K, Stachniss V, Schulte A. Longevity of cast gold inlays and partial crowns: a retrospective study at a dental school clinic. Clin Oral Investig 1999;3(2):100-4. 6. Mjor IA, Medina JE. Reasons for placement, replacement, and age of gold restorations in selected practices. Oper Dent 1993; 18(3):82-7. 7. Walton J, Gardner F, Agar J. A survey of crown and fixed partial denture failures: length of service and reasons for replacement. J Prosthet Dent 1986;56(4):416-21. 8. Libby G, Arcuri M, LaVelle W, Hebl L. Longevity of fixed partial dentures. J Prosthet Dent 1997;78(2):127-31. 9. Valderhaug J. A 15-year clinical evaluation of fixed prostheses. Acta Odontol Scand 1991;49(1):35-40. 10. Clinical Research Associates. Special report: product use survey 2005. CRA Newsletter 2005;29(10):3. 11. CRA Foundation. Zirconia vs. porcelainfused-to-metal (PFM): clinical performance at 1 year. CRA Newsletter 2006;30(11):1-4.
JADA, Vol. 138 http://jada.ada.org Copyright ©2007 American Dental Association. All rights reserved.
July 2007
1015