o...................
ARTICLE
...............................................
Dominic P. Lu, DDS
A chemomechanical system for caries removal and glass ionomer cement to restore fixed partial denture abutments When a fixed partial denture fails due to recurrent caries under the casting of the abutments, a remake process usually requires a great deal of cooperation, multiple lengthy appointments, and financial resources. Many patients with special needs may not have the cooperation, tolerance, and resources to support such treatment. This paper describes an alternative method that utilizes a chemomechanical system for caries removal followed by a conventional restorative material to treat those patients.
he restoration of recurrent caries under the abutment($ of a multi-unit fixed partial denture has always been a major concern of many restorative dentists. Without removal of the crown(s), the extent of decay under the crown is difficult to determine. Most methods*,2described in the past require the removal of the prosthesis for caries to be restored, but inadvertent extraction of the abutment is a real possibility3 during the course of removal, especially when periodontally mobile abutments are involved. Most removal devices require some destruction of the prostheses and/or their margins. Other methods requiring forceful removal of prostheses may cause fractures of abutments and even pulp exposure. Due to stress of the procedure, time involved, medical or mental status, cost, and other factors, some special patients may not be candidates for removal and remake of a multi-unit prosthesis. This paper provides an alternative method that utilizes a chemomechanical cariesremoval system to effect caries removal under the casting of a fixed partial denture abutment. Followup restoration with tooth colored glass ionomer cement, core buildup silver alloy/glass ionomer cement, composite, or amalgam can then be placed within the crown.
Treatment decision factors When a decision is made not to remake the failing prosthesis for a patient who is unable to tolerate lengthy remake procedures, the clinician must first determine if the prosthesis or abutment is mobile. If the abutment is firm, but the prosthe-
sis is loose, the cause is likely to be recurrent caries undermining the abutment(s), or dissolved cementing agent under the casting, or both. In these cases, prostheses are usually easy to remove, and the carious teeth are then restored and the prosthesis recemented.2 If mobility is due to periodontal bone loss of the involved abutment(s), but the prosthesis is firmly attached to the abutmentb), attempts to remove it will risk inadvertent extraction of the abutment. When both the prosthesis and the abutments are firm, the removal of the prosthesis may cause a fracture of an abutment. The last two situations are likely to result in a decision for the carious abutment(s) to be restored with the prosthesis remaining in place.
Caries removal After local anesthetic is administered, and if the tooth is vital, a round bur and excavating instruments are used to remove as much caries as possible so that access will be permitted. Gingival retraction or electrosurgery to remove gingival tissue at the carious area is sometimes necessary for improved access and visibility. A rubber dam is then placed. If the caries is extensive, it may not be possible for all of it to be removed with conventional rotary and hand instruments, due to limited access. The initial removal of caries by conventional rotary and hand instruments will create an access opening which will allow the long, thin applicator tip of the Caridex@system (National Patent Dental Products, Inc., New Brunswick, NJ 08901) to reach inside the crown. Four differently
Special Care in Dentistry, Vol12 No 6 1992 255
Fig 1. Caridex@system is used for caries removal from the casting.
designed applicator tips can be used interchangeably for removal of caries underneath a casting (Fig. 1). Carious material is softened and removed by being lightly abraded with the applicator as a continuous stream of chemical solution pulsates from the pump of the unit. The chemical solution is self limiting and removes only the irreversible, denatured, infected layer of carious denti11.4,~ The removal of caries should be verified with an explorer. If caries is still detectable, the Caridex@procedure is repeated until caries removal is complete. When the decay is extensive and the access opening is limited, an explorer may not be able to ensure complete removal of the caries; however, every attempt should be made to accomplish this goal. The preparation is then washed and dried with an air/water syringe. If the size and diameter of a regular syringe does not allow it to be inserted into the cavity preparation of the tooth, debridement may be accomplished by filling the reservoir of the Caridex@ system with plain water. The applicator tip should be used to direct the water into the cavity preparation in the same manner as it did the chemical solution to flush out all debris. A 1-cc tuberculin syringe (Becton Dickinson and Co., Rutherford, NJ 07070), loaded with a cleansing and drying agent such as Cavilax@(Premier Dental Products Company, Norristown, PA 19401),can be used to irrigate the interior of the casting. Final drying of the cavity preparation/casting surface can be achieved by drawing air into an empty tuberculin syringe and forcefully injecting it into the preparation several times.
Fig 2. Glass-ionomer cement forcefully injected into the crown to RII any void created by the decay process Inside the crown. (Rubber dam is temporarily removed here for purposes of photography.)
When the preparation is subgingival, a gingival retraction cord with hemostatic agent can be used to keep the area dry.
Restorative options A Type I1 tooth color restorative glass-ionomer cement (eg., GC Fuji I1 Glass Ionomer, G C international Corp., Scottsdale, AZ 85260) is chosen if the area to be restored is in the anterior, where esthetics is important. After being mixed, such material is loaded into a Centrix CR@syringe (Centrix, Inc., Stratford, CT). If the access opening for the cavity preparation is very small, the cement can even be loaded via a tuberculin syringe. Select a convenient spot at the access opening of the cavity preparation and inject the glass ionomer cement from the syringe into the casting to fill all voids inside the crown until the cement exudes from the crown (Fig. 2). Wait for the cement to set and remove the excess to avoid a "pullb a c k problem from the margin. Cover the cement with coating vanish to prevent crazing and cracking during setting. The restoration can be finished with a superfine diamond bur after the cement has been allowed sufficient time to set (Fig. 3). If the tooth to be restored has a post, if it is posteriorly located, or if the loss of tooth substance is extensive and core material is needed, then cermet cement (e.g., Miracle Mix, silver alloy/glass ionomer cement for core buildup, G C International Corp., Scottsdale, AZ 85260) is the material
256 Special Care in Dentistry, Vol12 No 6 1992
Fig 3. Post-op with satisfactory glassionomer restoration.
of choice. Removal of the smear layer is recommended: it can be achieved by the loading of a solution of polyacrylic acid in a 1-cc tuberculin syringe to irrigate for 10 s. A plain water wash delivered in the tuberculin syringe is followed by drying via use of the syringe delivery. If the tooth is vital, then 25% tannic acid solution is used for 30 s, after which the tooth is lightly washed and dried in the same manner: The cermet ionomer does not wet the surface of the tooth as readily as do members of the other, thinner, mixed ionomer cement family containing no silver alloy, and the drier surfaces of cermet cement may reduce wettability and decrease the chances of long term bonding to the tooth.6 The thick, puttylike viscosity of cermet cement in the centrix syringe is injected into the casting and overfilled to bond the tooth (Fig. 4). The viscous cement will squeeze and flush out any excess water or debris inside of the casting through laminar flow. Six min after placement, the excess is removed, the restoration can be finished with a rotary instrumenp, and the patient is dismissed (Fig. 5). if aesthetics is important and cermet cement is used for build-up around a post as a core, the patient can be rescheduled and the tooth can be reprepared by cutting the cermet cement core slightly back. Opaque can be placed over the cermet, followed by tooth colored composite.
Discussion For a variety of reasons, the Caridex@system has been used for the removal of caries under castings of bridge abutments with recurrent
Fig 4. Cermet cement is injected into the casting.
decay. It has various versatile 20-cc gauge needlelike long applicator tip designs, including an explorer tip, a small spoon excavator tip, and a 90" back action tip which can be used to reach the difficult access areas. It works by chemical softening of the carious material in a process by which the carious material is selectively dissolved away from unaffected tooth s t r ~ c t u r e . ~(The , ~ , ~procedure ,~ is accomplished by continuous flushing with the solution of N-monochloroDL-2-aminobutyric acid at the carious site and by gentle abrasion with the applicator tip.4,5,7-11) It allows for conservative removal of tooth structure. Unlike conventional operative procedures, the tooth structure unaffected with decay is not removed during the caries excavation. Consequently, pulpal exposure is minimized, and the strength of the restored tooth is improved by the availability of more healthy tooth structure which would otherwise be removed if a rotary instrument were ~ s e d .It~also , ~ provides a mechanical lock for a restoration by utilization of a glass ionomer to lock into the dentinal tubules and ~ n d e r c u t s . ~ Since Caridex@has been shown to remove the smear layer and bacteria in dentinal tubules, excellent adherence of the glass ionomer base is achieved, and the glass ionomer can cover all the internal dentinal walls.'*l2 Toxicology studies have shown that the solution is relatively safe, even when swallowed or when in contact with soft tissues.'* Though low edge strength and poor appearance have been cited as disadvantages in the past, the modern glass ionomer formulations are now stronger and
restoration of subgingival caries where moisture control makes placement of alloy or composite difficult.6 Cermet cement is fast setting; it can be injected subgingivally even where some moisture is present, providing a long term marginal seal for the casting. There is a controversy regarding removal of the smear layer prior to placement of the cement. Some studies indicate that it is mandatory for the smear layer to be removed prior to placement of a cermet cement6,whereas others indicate that the removal of smear may be a superfluous step and that the procedure does not improve the wet bond strength of the cement.22,"The author of this paper feels that the smear layer should be removed as recommended6,especially if the lesion Fig 5. Finished restoration with cermet under the casting is so extensive that cement. it may adversely affect the bond. more aesthetically ac~eptab1e.l~ They Cermet cement, with its rapid set, low also provide pulpal protection, early solubility, and improved tolerance, and added resistance to compression strengthz4,makes an caries not characteristic of microfill ideal restorative material for the resin.l4-I7 repair of a defective margin of a The fluoride content in the glass crown where aesthetics is not ionomer has been shown to be benefiimportant. It forms a good seal with cial for future caries p r e ~ e n t i o n . ' ~ J ~ J the ~ tooth and allows secondary dentin Nor does the contact of a glassformation to take place: ionomer restoration with the gingival Since contraindications of both the soft tissue in and of itself result in Caridex@chemomechanicalcariestissue irritati~n.'~,'~ Other authors removal system and glass ionomer have documented some bacteriostacement restorative materials are few, tidbactericidal properties of the they are relatively safe and effective to material.*O It is for these reasons that use for medically compromised and glass ionomer was chosen to be used handicapped patients. Nevertheless, as the restorative material in the they are contraindicated in patients technique just described. with known hypersensitivity to any of Where aesthetics is not of primary the component ingredients of glassconcern, such as in the posterior area, ionomer cement and the CaridexO the same system for caries removal chemical solution. Glass ionomer can be used, with a cermet glass cements may fail adhesively if the ionomer cement (ceramic metal) tooth surface is contaminated by substituted for the restorative blood, saliva, and debris.6 Caridex@ material. The cermet cement, with chemomechanical system for caries silver particles fused to reactive glass removal tends to remove carious tooth powder and fused at high temperasubstance slower than does a conventure, has a bond strength comparable tional high speed handpiece; consewith that of porcelain fused to gold.21 quently, the patient's cooperation and It could be used as a dentin substipatience are required. The tute with its application for repairing chemomechanical system can also be defective metal margins in crowns used to remove caries which extends and inlays2' McLean, the developer onto the root surfaces'O in conjunction of cermet ionomer cements, suggests with rotary instruments or as a sole that this material can be used for the agent.
Special Care in Dentisty, Vol12 No 6 1992 257
Summary A simple technique of using glass ionomer cement and a chemomechanical caries removal system to restore caries under the crowns of fixed partial denture abutments has been described. It is to be used when disadvantages outweigh advantages of removing the prosthesis to restore the abutment teeth. Whenever possible, if a prosthesis can be safely removed intact without compromising or damaging the dentition underneath, one should do so for direct access and visibility. If for any reason a clinician decides not to remove the prosthesis for a remake, or if the existing prosthesis should need to be stabilized for a time and a remake deferred to a later time, the described technique could be a very useful one. Dr. Lu is Director, General Practice Residency Program, The Allentown Hospital-Lehigh Valley Hospital Center, Allentown, PA 18069
1. Taleghani M, Carter G. Rebuilding abutment teeth to permit use of an existing bridge. Gen Dent 3354-6,1985. 2. Lu DP. Restoration of carious exposed abutment teeth to fit existing fixed partial denture. J Prosthet Dent 60678-81,1988.
3. Walker RS. Pin stabilization of a partially uncemented Maryland bridge. Gen Dent 36139-40,1988. 4. Goldman M, Kronman J. A preliminary report of a chemo-mechanical means of removing caries. J Am Dent Assoc 93:1149-53,1976. 5. McCune RJ. Report on a symposium on chemomechanicac caries removal: a multicenter study. Compend Contin Educ Dent 7151-80,1986. Cermet cements. J Am Dent 6. McLean JW. ASSOC 12043-7,1990. 7. McNierney HD, Petruzillo MA. A gentle approach to operative dentistry: the Caridex caries removal system. Gen Dent 34~282-4,1986. 8. Schutzbank SG, Galaini J, Kronman JH, Goldman M, Clark E. A comparative study of GK-101 and GK-IOIE in caries removal. J Dent Res 57861-4,1978. 9. Goldman M, Kronman JH, Wolski K, White RR. Caries removal to improve the bonding surface of dentine: a SEM study. NY State Dent J 53(3):20-21,1987. 10. Tavares M, Soparkar I'M, DePaola PF. Evaluation of a chemomechanical method of caries removal in root surface lesions. Quint Int 1929-32,1988. 11. Katz E. A comparison of the efficacy of Caridex caries removal system and conventional drills in complete caries removal (abstract). J Dent Res 66:134,1987. 12. Kronman JH, Goldman M, Habib CM, Mengel L, Shih L. EM study of collagen alteration after N-monochloro-DL-2aminobutyrate treatment (abstract). J Dent Res (Spec Iss) 56:A164,1977. 13. Tyas MJ, Beech DR. Clinical performance of three restorative materials for non-
288 Special Care in Dentistry, Vol12 No 6 1992
14. 15. 16.
17.
18. 19. 20.
21.
22. 23.
24.
undercut cervical abrasion lesions. Aust Dent J 30260-4,1985. Bitter NC. Glass ionomer-microfil for restoring cervical lesions. J Prosthet Dent 56:661-2,1986. Tobias RS. Pulpal response to glass ionomer cement. Br Dent J 14435-50, 1978. Pameijier C, Segal E, Richardson J. Pulpal response to a glass ionomer cement in primates. J Prosthet Dent 4636-40,1981. Voorde AV, Gerdts GJ, Murchison DF. Clinical uses of glass ionomer cement: a literature review. Quintessence 1953-61, 1988. McLean JW, Wilson AD. The clinical development of the glass ionomer cement. 111. Aust Dent J 22190-5,1977. Knibbs PJ, Plant CG, Pearson GJ. A clinical assessment of an anhydrous glass ionomer cement. Br Dent J 161:99-103,1986. Fitzgerald M, Heyes RJ, et nl. An evaluation of glass ionomer luting agent: bacterial leakage. J Am Dent Assoc 114:783-6,1987. Taleghani J, Leinfelder KF. Evaluation of a new glass ionomer cement with silver as a core build up under a cast restoration. Quintessence 1919-24,1988. Simmons JJ. Silver-alloy powder and glass ionomer cement. J Am Dent Assoc 1204952,1990. Mitchem J, Gronas D. Adhesion to dentin with and without smear layers under varying degrees of wetness (abstract). J Dent Res 68:321,1989. Croll TP. Replacement of defective Class I amalgam restorations with stratified glass ionomer-composite resin materials. Quint Int 20711-6,1989.
ARTICLE
...............................................
Dominic P. Lu, DDS
A chemomechanical system for caries removal and glass ionomer cement to restore fixed partial denture abutments When a fixed partial denture fails due to recurrent caries under the casting of the abutments, a remake process usually requires a great deal of cooperation, multiple lengthy appointments, and financial resources. Many patients with special needs may not have the cooperation, tolerance, and resources to support such treatment. This paper describes an alternative method that utilizes a chemomechanical system for caries removal followed by a conventional restorative material to treat those patients.
he restoration of recurrent caries under the abutment($ of a multi-unit fixed partial denture has always been a major concern of many restorative dentists. Without removal of the crown(s), the extent of decay under the crown is difficult to determine. Most methods*,2described in the past require the removal of the prosthesis for caries to be restored, but inadvertent extraction of the abutment is a real possibility3 during the course of removal, especially when periodontally mobile abutments are involved. Most removal devices require some destruction of the prostheses and/or their margins. Other methods requiring forceful removal of prostheses may cause fractures of abutments and even pulp exposure. Due to stress of the procedure, time involved, medical or mental status, cost, and other factors, some special patients may not be candidates for removal and remake of a multi-unit prosthesis. This paper provides an alternative method that utilizes a chemomechanical cariesremoval system to effect caries removal under the casting of a fixed partial denture abutment. Followup restoration with tooth colored glass ionomer cement, core buildup silver alloy/glass ionomer cement, composite, or amalgam can then be placed within the crown.
Treatment decision factors When a decision is made not to remake the failing prosthesis for a patient who is unable to tolerate lengthy remake procedures, the clinician must first determine if the prosthesis or abutment is mobile. If the abutment is firm, but the prosthe-
sis is loose, the cause is likely to be recurrent caries undermining the abutment(s), or dissolved cementing agent under the casting, or both. In these cases, prostheses are usually easy to remove, and the carious teeth are then restored and the prosthesis recemented.2 If mobility is due to periodontal bone loss of the involved abutment(s), but the prosthesis is firmly attached to the abutmentb), attempts to remove it will risk inadvertent extraction of the abutment. When both the prosthesis and the abutments are firm, the removal of the prosthesis may cause a fracture of an abutment. The last two situations are likely to result in a decision for the carious abutment(s) to be restored with the prosthesis remaining in place.
Caries removal After local anesthetic is administered, and if the tooth is vital, a round bur and excavating instruments are used to remove as much caries as possible so that access will be permitted. Gingival retraction or electrosurgery to remove gingival tissue at the carious area is sometimes necessary for improved access and visibility. A rubber dam is then placed. If the caries is extensive, it may not be possible for all of it to be removed with conventional rotary and hand instruments, due to limited access. The initial removal of caries by conventional rotary and hand instruments will create an access opening which will allow the long, thin applicator tip of the Caridex@system (National Patent Dental Products, Inc., New Brunswick, NJ 08901) to reach inside the crown. Four differently
Special Care in Dentistry, Vol12 No 6 1992 255
Fig 1. Caridex@system is used for caries removal from the casting.
designed applicator tips can be used interchangeably for removal of caries underneath a casting (Fig. 1). Carious material is softened and removed by being lightly abraded with the applicator as a continuous stream of chemical solution pulsates from the pump of the unit. The chemical solution is self limiting and removes only the irreversible, denatured, infected layer of carious denti11.4,~ The removal of caries should be verified with an explorer. If caries is still detectable, the Caridex@procedure is repeated until caries removal is complete. When the decay is extensive and the access opening is limited, an explorer may not be able to ensure complete removal of the caries; however, every attempt should be made to accomplish this goal. The preparation is then washed and dried with an air/water syringe. If the size and diameter of a regular syringe does not allow it to be inserted into the cavity preparation of the tooth, debridement may be accomplished by filling the reservoir of the Caridex@ system with plain water. The applicator tip should be used to direct the water into the cavity preparation in the same manner as it did the chemical solution to flush out all debris. A 1-cc tuberculin syringe (Becton Dickinson and Co., Rutherford, NJ 07070), loaded with a cleansing and drying agent such as Cavilax@(Premier Dental Products Company, Norristown, PA 19401),can be used to irrigate the interior of the casting. Final drying of the cavity preparation/casting surface can be achieved by drawing air into an empty tuberculin syringe and forcefully injecting it into the preparation several times.
Fig 2. Glass-ionomer cement forcefully injected into the crown to RII any void created by the decay process Inside the crown. (Rubber dam is temporarily removed here for purposes of photography.)
When the preparation is subgingival, a gingival retraction cord with hemostatic agent can be used to keep the area dry.
Restorative options A Type I1 tooth color restorative glass-ionomer cement (eg., GC Fuji I1 Glass Ionomer, G C international Corp., Scottsdale, AZ 85260) is chosen if the area to be restored is in the anterior, where esthetics is important. After being mixed, such material is loaded into a Centrix CR@syringe (Centrix, Inc., Stratford, CT). If the access opening for the cavity preparation is very small, the cement can even be loaded via a tuberculin syringe. Select a convenient spot at the access opening of the cavity preparation and inject the glass ionomer cement from the syringe into the casting to fill all voids inside the crown until the cement exudes from the crown (Fig. 2). Wait for the cement to set and remove the excess to avoid a "pullb a c k problem from the margin. Cover the cement with coating vanish to prevent crazing and cracking during setting. The restoration can be finished with a superfine diamond bur after the cement has been allowed sufficient time to set (Fig. 3). If the tooth to be restored has a post, if it is posteriorly located, or if the loss of tooth substance is extensive and core material is needed, then cermet cement (e.g., Miracle Mix, silver alloy/glass ionomer cement for core buildup, G C International Corp., Scottsdale, AZ 85260) is the material
256 Special Care in Dentistry, Vol12 No 6 1992
Fig 3. Post-op with satisfactory glassionomer restoration.
of choice. Removal of the smear layer is recommended: it can be achieved by the loading of a solution of polyacrylic acid in a 1-cc tuberculin syringe to irrigate for 10 s. A plain water wash delivered in the tuberculin syringe is followed by drying via use of the syringe delivery. If the tooth is vital, then 25% tannic acid solution is used for 30 s, after which the tooth is lightly washed and dried in the same manner: The cermet ionomer does not wet the surface of the tooth as readily as do members of the other, thinner, mixed ionomer cement family containing no silver alloy, and the drier surfaces of cermet cement may reduce wettability and decrease the chances of long term bonding to the tooth.6 The thick, puttylike viscosity of cermet cement in the centrix syringe is injected into the casting and overfilled to bond the tooth (Fig. 4). The viscous cement will squeeze and flush out any excess water or debris inside of the casting through laminar flow. Six min after placement, the excess is removed, the restoration can be finished with a rotary instrumenp, and the patient is dismissed (Fig. 5). if aesthetics is important and cermet cement is used for build-up around a post as a core, the patient can be rescheduled and the tooth can be reprepared by cutting the cermet cement core slightly back. Opaque can be placed over the cermet, followed by tooth colored composite.
Discussion For a variety of reasons, the Caridex@system has been used for the removal of caries under castings of bridge abutments with recurrent
Fig 4. Cermet cement is injected into the casting.
decay. It has various versatile 20-cc gauge needlelike long applicator tip designs, including an explorer tip, a small spoon excavator tip, and a 90" back action tip which can be used to reach the difficult access areas. It works by chemical softening of the carious material in a process by which the carious material is selectively dissolved away from unaffected tooth s t r ~ c t u r e . ~(The , ~ , ~procedure ,~ is accomplished by continuous flushing with the solution of N-monochloroDL-2-aminobutyric acid at the carious site and by gentle abrasion with the applicator tip.4,5,7-11) It allows for conservative removal of tooth structure. Unlike conventional operative procedures, the tooth structure unaffected with decay is not removed during the caries excavation. Consequently, pulpal exposure is minimized, and the strength of the restored tooth is improved by the availability of more healthy tooth structure which would otherwise be removed if a rotary instrument were ~ s e d .It~also , ~ provides a mechanical lock for a restoration by utilization of a glass ionomer to lock into the dentinal tubules and ~ n d e r c u t s . ~ Since Caridex@has been shown to remove the smear layer and bacteria in dentinal tubules, excellent adherence of the glass ionomer base is achieved, and the glass ionomer can cover all the internal dentinal walls.'*l2 Toxicology studies have shown that the solution is relatively safe, even when swallowed or when in contact with soft tissues.'* Though low edge strength and poor appearance have been cited as disadvantages in the past, the modern glass ionomer formulations are now stronger and
restoration of subgingival caries where moisture control makes placement of alloy or composite difficult.6 Cermet cement is fast setting; it can be injected subgingivally even where some moisture is present, providing a long term marginal seal for the casting. There is a controversy regarding removal of the smear layer prior to placement of the cement. Some studies indicate that it is mandatory for the smear layer to be removed prior to placement of a cermet cement6,whereas others indicate that the removal of smear may be a superfluous step and that the procedure does not improve the wet bond strength of the cement.22,"The author of this paper feels that the smear layer should be removed as recommended6,especially if the lesion Fig 5. Finished restoration with cermet under the casting is so extensive that cement. it may adversely affect the bond. more aesthetically ac~eptab1e.l~ They Cermet cement, with its rapid set, low also provide pulpal protection, early solubility, and improved tolerance, and added resistance to compression strengthz4,makes an caries not characteristic of microfill ideal restorative material for the resin.l4-I7 repair of a defective margin of a The fluoride content in the glass crown where aesthetics is not ionomer has been shown to be benefiimportant. It forms a good seal with cial for future caries p r e ~ e n t i o n . ' ~ J ~ J the ~ tooth and allows secondary dentin Nor does the contact of a glassformation to take place: ionomer restoration with the gingival Since contraindications of both the soft tissue in and of itself result in Caridex@chemomechanicalcariestissue irritati~n.'~,'~ Other authors removal system and glass ionomer have documented some bacteriostacement restorative materials are few, tidbactericidal properties of the they are relatively safe and effective to material.*O It is for these reasons that use for medically compromised and glass ionomer was chosen to be used handicapped patients. Nevertheless, as the restorative material in the they are contraindicated in patients technique just described. with known hypersensitivity to any of Where aesthetics is not of primary the component ingredients of glassconcern, such as in the posterior area, ionomer cement and the CaridexO the same system for caries removal chemical solution. Glass ionomer can be used, with a cermet glass cements may fail adhesively if the ionomer cement (ceramic metal) tooth surface is contaminated by substituted for the restorative blood, saliva, and debris.6 Caridex@ material. The cermet cement, with chemomechanical system for caries silver particles fused to reactive glass removal tends to remove carious tooth powder and fused at high temperasubstance slower than does a conventure, has a bond strength comparable tional high speed handpiece; consewith that of porcelain fused to gold.21 quently, the patient's cooperation and It could be used as a dentin substipatience are required. The tute with its application for repairing chemomechanical system can also be defective metal margins in crowns used to remove caries which extends and inlays2' McLean, the developer onto the root surfaces'O in conjunction of cermet ionomer cements, suggests with rotary instruments or as a sole that this material can be used for the agent.
Special Care in Dentisty, Vol12 No 6 1992 257
Summary A simple technique of using glass ionomer cement and a chemomechanical caries removal system to restore caries under the crowns of fixed partial denture abutments has been described. It is to be used when disadvantages outweigh advantages of removing the prosthesis to restore the abutment teeth. Whenever possible, if a prosthesis can be safely removed intact without compromising or damaging the dentition underneath, one should do so for direct access and visibility. If for any reason a clinician decides not to remove the prosthesis for a remake, or if the existing prosthesis should need to be stabilized for a time and a remake deferred to a later time, the described technique could be a very useful one. Dr. Lu is Director, General Practice Residency Program, The Allentown Hospital-Lehigh Valley Hospital Center, Allentown, PA 18069
1. Taleghani M, Carter G. Rebuilding abutment teeth to permit use of an existing bridge. Gen Dent 3354-6,1985. 2. Lu DP. Restoration of carious exposed abutment teeth to fit existing fixed partial denture. J Prosthet Dent 60678-81,1988.
3. Walker RS. Pin stabilization of a partially uncemented Maryland bridge. Gen Dent 36139-40,1988. 4. Goldman M, Kronman J. A preliminary report of a chemo-mechanical means of removing caries. J Am Dent Assoc 93:1149-53,1976. 5. McCune RJ. Report on a symposium on chemomechanicac caries removal: a multicenter study. Compend Contin Educ Dent 7151-80,1986. Cermet cements. J Am Dent 6. McLean JW. ASSOC 12043-7,1990. 7. McNierney HD, Petruzillo MA. A gentle approach to operative dentistry: the Caridex caries removal system. Gen Dent 34~282-4,1986. 8. Schutzbank SG, Galaini J, Kronman JH, Goldman M, Clark E. A comparative study of GK-101 and GK-IOIE in caries removal. J Dent Res 57861-4,1978. 9. Goldman M, Kronman JH, Wolski K, White RR. Caries removal to improve the bonding surface of dentine: a SEM study. NY State Dent J 53(3):20-21,1987. 10. Tavares M, Soparkar I'M, DePaola PF. Evaluation of a chemomechanical method of caries removal in root surface lesions. Quint Int 1929-32,1988. 11. Katz E. A comparison of the efficacy of Caridex caries removal system and conventional drills in complete caries removal (abstract). J Dent Res 66:134,1987. 12. Kronman JH, Goldman M, Habib CM, Mengel L, Shih L. EM study of collagen alteration after N-monochloro-DL-2aminobutyrate treatment (abstract). J Dent Res (Spec Iss) 56:A164,1977. 13. Tyas MJ, Beech DR. Clinical performance of three restorative materials for non-
288 Special Care in Dentistry, Vol12 No 6 1992
14. 15. 16.
17.
18. 19. 20.
21.
22. 23.
24.
undercut cervical abrasion lesions. Aust Dent J 30260-4,1985. Bitter NC. Glass ionomer-microfil for restoring cervical lesions. J Prosthet Dent 56:661-2,1986. Tobias RS. Pulpal response to glass ionomer cement. Br Dent J 14435-50, 1978. Pameijier C, Segal E, Richardson J. Pulpal response to a glass ionomer cement in primates. J Prosthet Dent 4636-40,1981. Voorde AV, Gerdts GJ, Murchison DF. Clinical uses of glass ionomer cement: a literature review. Quintessence 1953-61, 1988. McLean JW, Wilson AD. The clinical development of the glass ionomer cement. 111. Aust Dent J 22190-5,1977. Knibbs PJ, Plant CG, Pearson GJ. A clinical assessment of an anhydrous glass ionomer cement. Br Dent J 161:99-103,1986. Fitzgerald M, Heyes RJ, et nl. An evaluation of glass ionomer luting agent: bacterial leakage. J Am Dent Assoc 114:783-6,1987. Taleghani J, Leinfelder KF. Evaluation of a new glass ionomer cement with silver as a core build up under a cast restoration. Quintessence 1919-24,1988. Simmons JJ. Silver-alloy powder and glass ionomer cement. J Am Dent Assoc 1204952,1990. Mitchem J, Gronas D. Adhesion to dentin with and without smear layers under varying degrees of wetness (abstract). J Dent Res 68:321,1989. Croll TP. Replacement of defective Class I amalgam restorations with stratified glass ionomer-composite resin materials. Quint Int 20711-6,1989.
