- Email: [email protected]
Resin restorations for anterior teeth—1995
RESIN
RESTORATIONS FOR ANTERIOR TEETH-
onservative restoration of anterior teeth has always been a challenge. As recently as 30 years ago, small gold alloy castings were seated into anterior teeth. Tooth-colored restorations were then placed in the castings on the facial surfaces in an attempt to create acceptable esthetics. Silicate cement, used actively until the early 1960s, provided a moderately acceptable esthetic result, but only for several years. Unfilled resins, when initially introduced, had disagreeable color degeneration, but later unfilled resins with improved initiator-catalyst systems provided several years of esthetic service. Early composite resins (19601970) developed rough surfaces and mild-to-severe color degeneration over a few years of service. During the mid-1970s smaller particle fillers provided longer lasting composites, but most of these resins degenerated and had rough surfaces and color degeneration over several years. For the first time, relatively smooth restorations with little or no color degeneration were available in the late 1970s and early 1980s. These restorations could be expected to serve quite well, both functionally and esthetically, for 10 years or more. In addition, microfill resins (silicondioxide filled) were introduced in the mid-1970s amid criticism and doubt. After 20 years, they are now well accepted. The current generation of
glass- and silicon dioxide-filled hybrid composites was introduced in the mid-1980s. This is the type of restorative resin used most commonly today for both anterior and posterior esthetic intracoronal restorations. After 10 years of clinical use and research, these materials are serving amazingly well. Their life expectancy should be several decades in anterior teeth, if placed and finished adequately. What is the state of the art for conservative anterior tooth restorations?1,2 The following discussion includes - suggestions for anterior tooth restorations displaying a significant amount of restorative material on tooth facial surfaces; - suggestions for those restorations without major restorative material display. ANTERIOR TOOTH RESTORATIONS WITH SIGNIFICANT FACIAL DISPLAY
Large Class III, IV and V restorations often display a significant amount of their facial surfaces to the view of an observer. If hybrid resins (examples: Charisma, Heraeus Kulzer; Conquest, Jeneric-Pentron; Herculite, Kerr; Pertac, ESPEPremier; Tetric, Vivadent; TPH, Caulk; Z-100, 3M) are used as the sole restorative material in these locations, the esthetic appearance is good for a few months. After that, the restoration surfaces become rough and
995
feel slightly irregular to the tongue. Superficial stains will accumulate concomitantly with the surface roughening. In many patients this moderatelevel esthetic situation is tolerable or acceptable. However, in other, more discriminating persons, or those with a smile that displays tooth surfaces to a major degree, such restorations are unacceptable. The following technique for conservative restoration of anterior teeth, satisfying esthetic needs for many years, should be used for patients displaying large portions of anterior facial tooth surfaces. Tooth preparations are made as usual, using long bevels (at least 1 millimeter) on all external enamel cavo-surface margins, placed with a tapered rotary diamond instrument. Mylar strips are placed as usual. The lingual aspect of the restoration is filled with hybrid resin, leaving about 1 mm of tooth preparation unfilled on the tooth facial surface. Incremental placement and curing are used when the resin is deeper than 2 mm. The superficial 1 mm of the restoration is filled with a microfill resin (examples: Durafil, Kulzer; Perfection, Den-Mat; Renamel, Cosmedent; Silux, 3M). Bonding agent is not needed between the hybrid layers and the microfill layer because the presence of an air-inhibited surface on the last layer of hybrid resin provides good bonding with the microfill. JADA, Vol. 126, October 1995 1427
CHRISTENSEN Advantages of this technique are the hybrid lingual portion provides high strength and low expansion and contraction; ease of finish; and moderate opacity, reducing the chance of too much incisal translucence. The microfill facial portion provides low wear, smoothness, minimal subsequent superficial staining and excellent translucency. Restorations accomplished using the described procedure serve both functionally and esthetically for many years. Most are undetectable to the human eye because of smooth, unstained microfill surfaces that become even smoother after many years of toothbrushing. ANTERIOR TOOTH RESTORATIONS WITHOUT SIGNIFICANT FACIAL DISPLAY
Some Class III restorations can be prepared entirely from the lingual surface. There is no reason to restore these preparations with microfill resin. Hybrid resin brands, described previously, are used without a superficial layer of microfill resin. These restorations are strong and easily finished, and they should serve almost indefinitely if margins are not mutilated during finishing. Many Class V restorations Dr. Christensen Is cannot be co-founder and seviewed by canior consultant of Clinical Research sual observers Assoclates, 3707 N. during normal Canyon Rd., Suite conversation or No. 7A, Provo, Utah 84604, and is a when smiling. member of JADA's Hybrid resins editorial board. He has a master's dealone are indigree In restorative in these cated dentistry and a doctorate In education situations beand psychology. He cause hybrid Is board certified In resin can be prosthodontics. 1428 JADA, Vol. 126, October 1995
finished much more easily without margin mutilation than microfill resin. Currently, some clinicians are recommending microfill resins in Class V abfraction areas because of the flexibility present in microfills. This concept is acceptable if extreme care is used in finishing the microfill to avoid ditched and chipped margins. SUPERFICIAL BONDINGSEALING AGENTS
the body of a restoration or new dental caries forms around restoration margins. Should such restorations be repaired or replaced? After a few hours in the mouth, resin restorations cannot be expected to bond well to new repair resin, because the chemical activity of the original restorative resin has been exhausted. If resin repair is being considered, and either the repair segment or the remnant of remaining resin is not expected to be self-retentive within the tooth, the entire restoration should be replaced. If the old restoration can be considered retentive by itself, irrespective of the new portion, a repair can be considered. Usually, total replacement is better than repair.
Microfilled, thin viscosity resins have been promoted for placement over the surface of resin restorations after finishing procedures (examples: Fortify, Bisco Dental Products; Permaseal, Ultradent Products, Inc.). If margins of resin restorations are clearly chipped, bruised or otherwise mutilated during finishing procedures, it is probably desirable to acid etch the restoration surface and margins and place one of these sealing resins. The longevity of such sealing resins on superficial areas cannot be expected to be indefinite. However, penetration of these resins into irregularities around margins, voids in the restoration or cracks or irregularities in the tooth surface is apparent microscopically, and reduction in subsequent staining of those respective areas should be expected. Although routine use of superficial sealing resins is probably not necessary, they certainly do not appear to cause any negative influence.
Resin restorations for anterior teeth, properly planned and well placed, should be expected to serve many years. Small resin restorations in anterior teeth may even be lifetime restorations. Class III, IV and V resin restorations with large facial display are best when hybrid resin is placed internally and microfill resin is placed facially. Restorations without significant facial display are best treated with hybrid resin alone. Although new, more refined resin systems will come, the current state of the art for anterior resin restorations is excellent and certainly the best it has ever been. .
REPAIR OF PREVIOUSLY PLACED ANTERIOR RESIN RESTORATIONS
Information on the products mentioned in this article may be available from the author.
Occasionally, a piece of resin chips away from a Class IV restoration, a void appears in
1. Christensen GJ. Microfills vs. hybrids-is there a universal composite resin? JADA 1991;122(9):79. 2. Christensen GJ. Don't underestimate the Class 2 resin. JADA 1992;123(3):103-4.
SUMMARY
RESTORATIONS FOR ANTERIOR TEETH-
onservative restoration of anterior teeth has always been a challenge. As recently as 30 years ago, small gold alloy castings were seated into anterior teeth. Tooth-colored restorations were then placed in the castings on the facial surfaces in an attempt to create acceptable esthetics. Silicate cement, used actively until the early 1960s, provided a moderately acceptable esthetic result, but only for several years. Unfilled resins, when initially introduced, had disagreeable color degeneration, but later unfilled resins with improved initiator-catalyst systems provided several years of esthetic service. Early composite resins (19601970) developed rough surfaces and mild-to-severe color degeneration over a few years of service. During the mid-1970s smaller particle fillers provided longer lasting composites, but most of these resins degenerated and had rough surfaces and color degeneration over several years. For the first time, relatively smooth restorations with little or no color degeneration were available in the late 1970s and early 1980s. These restorations could be expected to serve quite well, both functionally and esthetically, for 10 years or more. In addition, microfill resins (silicondioxide filled) were introduced in the mid-1970s amid criticism and doubt. After 20 years, they are now well accepted. The current generation of
glass- and silicon dioxide-filled hybrid composites was introduced in the mid-1980s. This is the type of restorative resin used most commonly today for both anterior and posterior esthetic intracoronal restorations. After 10 years of clinical use and research, these materials are serving amazingly well. Their life expectancy should be several decades in anterior teeth, if placed and finished adequately. What is the state of the art for conservative anterior tooth restorations?1,2 The following discussion includes - suggestions for anterior tooth restorations displaying a significant amount of restorative material on tooth facial surfaces; - suggestions for those restorations without major restorative material display. ANTERIOR TOOTH RESTORATIONS WITH SIGNIFICANT FACIAL DISPLAY
Large Class III, IV and V restorations often display a significant amount of their facial surfaces to the view of an observer. If hybrid resins (examples: Charisma, Heraeus Kulzer; Conquest, Jeneric-Pentron; Herculite, Kerr; Pertac, ESPEPremier; Tetric, Vivadent; TPH, Caulk; Z-100, 3M) are used as the sole restorative material in these locations, the esthetic appearance is good for a few months. After that, the restoration surfaces become rough and
995
feel slightly irregular to the tongue. Superficial stains will accumulate concomitantly with the surface roughening. In many patients this moderatelevel esthetic situation is tolerable or acceptable. However, in other, more discriminating persons, or those with a smile that displays tooth surfaces to a major degree, such restorations are unacceptable. The following technique for conservative restoration of anterior teeth, satisfying esthetic needs for many years, should be used for patients displaying large portions of anterior facial tooth surfaces. Tooth preparations are made as usual, using long bevels (at least 1 millimeter) on all external enamel cavo-surface margins, placed with a tapered rotary diamond instrument. Mylar strips are placed as usual. The lingual aspect of the restoration is filled with hybrid resin, leaving about 1 mm of tooth preparation unfilled on the tooth facial surface. Incremental placement and curing are used when the resin is deeper than 2 mm. The superficial 1 mm of the restoration is filled with a microfill resin (examples: Durafil, Kulzer; Perfection, Den-Mat; Renamel, Cosmedent; Silux, 3M). Bonding agent is not needed between the hybrid layers and the microfill layer because the presence of an air-inhibited surface on the last layer of hybrid resin provides good bonding with the microfill. JADA, Vol. 126, October 1995 1427
CHRISTENSEN Advantages of this technique are the hybrid lingual portion provides high strength and low expansion and contraction; ease of finish; and moderate opacity, reducing the chance of too much incisal translucence. The microfill facial portion provides low wear, smoothness, minimal subsequent superficial staining and excellent translucency. Restorations accomplished using the described procedure serve both functionally and esthetically for many years. Most are undetectable to the human eye because of smooth, unstained microfill surfaces that become even smoother after many years of toothbrushing. ANTERIOR TOOTH RESTORATIONS WITHOUT SIGNIFICANT FACIAL DISPLAY
Some Class III restorations can be prepared entirely from the lingual surface. There is no reason to restore these preparations with microfill resin. Hybrid resin brands, described previously, are used without a superficial layer of microfill resin. These restorations are strong and easily finished, and they should serve almost indefinitely if margins are not mutilated during finishing. Many Class V restorations Dr. Christensen Is cannot be co-founder and seviewed by canior consultant of Clinical Research sual observers Assoclates, 3707 N. during normal Canyon Rd., Suite conversation or No. 7A, Provo, Utah 84604, and is a when smiling. member of JADA's Hybrid resins editorial board. He has a master's dealone are indigree In restorative in these cated dentistry and a doctorate In education situations beand psychology. He cause hybrid Is board certified In resin can be prosthodontics. 1428 JADA, Vol. 126, October 1995
finished much more easily without margin mutilation than microfill resin. Currently, some clinicians are recommending microfill resins in Class V abfraction areas because of the flexibility present in microfills. This concept is acceptable if extreme care is used in finishing the microfill to avoid ditched and chipped margins. SUPERFICIAL BONDINGSEALING AGENTS
the body of a restoration or new dental caries forms around restoration margins. Should such restorations be repaired or replaced? After a few hours in the mouth, resin restorations cannot be expected to bond well to new repair resin, because the chemical activity of the original restorative resin has been exhausted. If resin repair is being considered, and either the repair segment or the remnant of remaining resin is not expected to be self-retentive within the tooth, the entire restoration should be replaced. If the old restoration can be considered retentive by itself, irrespective of the new portion, a repair can be considered. Usually, total replacement is better than repair.
Microfilled, thin viscosity resins have been promoted for placement over the surface of resin restorations after finishing procedures (examples: Fortify, Bisco Dental Products; Permaseal, Ultradent Products, Inc.). If margins of resin restorations are clearly chipped, bruised or otherwise mutilated during finishing procedures, it is probably desirable to acid etch the restoration surface and margins and place one of these sealing resins. The longevity of such sealing resins on superficial areas cannot be expected to be indefinite. However, penetration of these resins into irregularities around margins, voids in the restoration or cracks or irregularities in the tooth surface is apparent microscopically, and reduction in subsequent staining of those respective areas should be expected. Although routine use of superficial sealing resins is probably not necessary, they certainly do not appear to cause any negative influence.
Resin restorations for anterior teeth, properly planned and well placed, should be expected to serve many years. Small resin restorations in anterior teeth may even be lifetime restorations. Class III, IV and V resin restorations with large facial display are best when hybrid resin is placed internally and microfill resin is placed facially. Restorations without significant facial display are best treated with hybrid resin alone. Although new, more refined resin systems will come, the current state of the art for anterior resin restorations is excellent and certainly the best it has ever been. .
REPAIR OF PREVIOUSLY PLACED ANTERIOR RESIN RESTORATIONS
Information on the products mentioned in this article may be available from the author.
Occasionally, a piece of resin chips away from a Class IV restoration, a void appears in
1. Christensen GJ. Microfills vs. hybrids-is there a universal composite resin? JADA 1991;122(9):79. 2. Christensen GJ. Don't underestimate the Class 2 resin. JADA 1992;123(3):103-4.
SUMMARY