Intemational Endodontic Joumai (1990) 23,172-178
Clinical application of glass ionomer cements in endodontics: case reports G. G. STEWART 1410 Medtcal Arts Building, Philadelphia, USA Summary. The usefulness of glass ionomer cements in endodontics is illustrated by selected case histories. The situations varied from root repair to root endfilling.The use of regular glass ionomer cement and a reinforced version are presented. In addition, the preparation of a modified glass ionomer cement, that could be used alone, or with gutta-percha, for root canal obturation is described. Introduction The glass ionotner cements, which are primarily a combination of alumino-silicate glass and polyacrylic acid possess the unique ability to bond chemically to dentine and enamel. In 1972, Wilson and Kent introduced the glass ionomer cements for dental restorations. Since that time, many studies have been published describing their clinical application (McLean & Wilson 1972, Simmons 1985). The release of fluoride ions which was reported by Forsten (1977) nnay help to prevent recurrent caries. Pitt Ford (1976) was the first to report the use of glass ionomer cements in root canal treatment. His was a laboratory study, where gutta-percha cones and silver cones were cemented with glass ionomer cement in extracted teeth. Using dye penetration, he found that glass ionomer cement prevented leakage of the dye substance. In a personal communication, he revealed that the setting time of the cement used was too rapid for lateral condensation of gutta-percha. In 1983, Ztnener and Dominguez suggested that glass ionomer cement could be used for luting endodontic itnplants. The tissue compatibility was demonstrated by Zetterqvist et al. (1987) in an animal study which compared the cennent with amalgann for root end fillings. After 3- and 6-month Correspondence: Dr G. G. Stewart, 1410 Medical Arts Building, 1061 Walnut Street, Philadelphia, PA 19102, USA. 172
intervals, complete healing was observed, with mature alveolar bone surrounding the apicected roots. In another study, Blackman et at. (1989) tested tissue compatibility in the rat tibia, and found bone apposition in areas where a glass ionomer-silver cement was used. When zinc oxide-eugenol cement was implanted, healing occurred by fibrosis. The author will present a selection of cases where glass ionomer cements were used in the treatment of endodontic problems. The use of a regular glass ionomer cement will be illustrated, as well as a reinforced and a modified glass ionomer cement. The modified glass ionomer was prepared for use as a root canal cement by placing the following on a sterile glass slab: (i) two scoops of barium sulphate (the plastic scoop was provided with KetacBond'); (ii) four drops of Ketac-Bond liquid were placed adjacent to this for 20 minutes of working time (or three drops of the liquid for 55 minutes); (iii) triturate one capsule of Ketac-Fil in an appropriate machine for 10 seconds at medium speed; the resultant mix is then ejected on to the glass slab. The barium sulphate is spatulated into the Ketac-Bond liquid. The mix is then spatulated with the prepared Ketac-Fil, until a smooth creamy mix is produced. When used with gutta-percha, a reamer or file can be used to coat the walls of the root canal. The tnaster gutta-percha cone is then coated with the mix and condensed into the canal, using auxiliary cones. When multirooted teeth are being fitted, each nnaster cone and auxiliary cone should be prepared before nnixing is started to allow adequate working time. ' Espe GmbH, Seefeld, Oberbay, W. Germany.
Glass ionamer cements m endoditntics
(a) (b) (c) Fig. 1. (a) Two mandibular central incisor teeth which had been treated previously; the right incisor has a periapical radiolucent area, (b) The radiopaque medication was again used in the canal, and the root-end seal had been exfoliated, (c) Sixteen months later the root was sealed with a modified gJass ionomer cement and there wa.s excellent healing. If the modified glass ionomer alone is to be used as the root canal sealing agent, it can be introduced in increments, or placed in an appropriate syringe and injected. The mass can be cotnpacted forward using McSpadden Compactors'. If necessary, the mass can be compacted further with blunt pluggers, v\-hcn the mix gels. When the modified glass ionomer cement was used for obturation of root canals, the irtformed consent of the patient was always obtained. Case histories Case I
The first case is that of a j6-year-old woman who had a history of trauma, resulting in the need for root canal treatment ofthe mandibular central incisor teeth. Her general dentist had filled the root canals, and amputated the apices of the teeth before placing retrograde root fillings. The periradicular tissues failed to heal around the right central incisor, and a sinus tract had developed (Fig. la). Since there was a history of trauma, and the walls ofthe tooth were thin, the author elected to retreat the tooth, using calcium hydroxide to encourage healing. ' Dentsply, York, PA, 0SA.
Several weeks after the initial treatment, the patient found a small piece of silver amalgam in her mouth. A radiograph indicated that the retrograde filling of the tooth being treated was no longer present, and the silver amalgam had therefore been exfoliated through tbe sinus tract (Fig. I b). The canal was irrigated and again treated with calcium hydroxide. The pulp chamber was sealed with gutta-percha and zinc phosphate cement. To provide further protection for the crown, an outer layer of composite resin was added. Although the patient failed to return for periodic dressing changes for 16 months, the radiograph taken after this interval showed excellent periradicular healing. The canal was irrigated and cleaned before it was obturated with the modified glass ionomer cement, and the crown was restored with composite resin. The radiograph of the obturated tooth is shown in Fig. lc. Two years have elapsed since the tooth xvas obturated. Unforttsnately the patient has not returned for review, but telephone contact with the patient indicated that the tooth was completely comfortable and firm. Gase 2
The next case is that of a 52-year-old man. His mandibular right first molar tooth was acutely painful and sensitive to both heat and cold.
G. G. Stewart
Fig. 2. (a) The master gutta-percha cones in position for verification, (b) Radiograph showing the sealed root canals.
with pain radiating to his ear. There was no evidence of caries present, although the marginal ridges did have deep grooves that were discoloured and possibly cracked. After isolation, the pulp was removed under local anaesthesia, and gutta-percha was used to cover the floor ofthe pulp chamber to prevent blockage ofthe canal entrances by the cement. The purpose of the reinforced glass ionomer was to prevent leakage from the cracks that could then be seen extending to the floor of the pulp chamber. .4 further reason for the reinforced glass ionomcr cement was to help prevent complete fracture ofthe crown during treatment. After the glass ionomer cement had set, the chamber of the tooth was re-entered with a high speed bur and water spray, retaining a wall of reinforced glass ionomer for support. The gutta-percha was removed from the floor of the puip chamber to allow routine cleaning and shaping of the canals. At the second visit the canals were cleaned before the master gutta-percha cones were selected. The cones were checked for accuracj' as seen in Fig. 2a. The modified glass ionomer was used as a root canai cement with the gutta-percha cones. A small root canal instrument was used to coat the walls of each canal with the modified glass ionomer cement. The master gutta-percha cones were also coated with the cement and firmly seated in each canal. As suggested by Czonstkowsky et al. (1985), warm gutta-
percha was injected into each canal until it was completely filled. The excess gutta-percha was removed with a hot instrument, and the gutta-percha was condensed with appropriate pluggers. The chamber ofthe tooth was filled with the reinforced glass ionomcr cement, to provide maximum protection until a crown could be placed. The final radiograph (Fig. 2b) shows complete obturation with a small amount of extruded sealer. The patient experienced no discomfort following treatment. The patient returned for 6-month and 1year recall visits, when it was observed that the tooth remained comfortable and the supporting tissues were healthy. Gase 3 This case is that of a 42-year-old woman who was referred approximately 30 years after an accident that produced marked trauma to the face. Following the accident, there was periodic awareness in the area ofthe maxillary left central incisor tooth. The radiograph taken ofthe area at the first visit showed extensive internal resorption (Fig. 3a). Although the prognosis was questionable, an attempt was made to salvage the tooth with the aid of calcium hydroxide therapy (Stewart 1975). After isolation, the pulp chamber was opened and the canai explored. Several perforations were detected with a fine root canal instrument. The completely necrotic pulp was
Glass ionotncr cements in endodontics
Fig. 3. (a) Radiograph taken in 1985 showing marked resorption in the central incisor, (b) Continued healing of the supporting tissues as noted at the 6-month checl;-up visit. removed with files and repeated irrigation with alternating solutions of hydrogen peroxide and sodium hypochlorite. The canal was dried with absorbent paper points and filled with a thick mixture of calcium hydroxide and metacresylacetate. Barium sulphate, 20 per cent by weight, was added to the calcium hydroxide to enhance radiopacity. The patient was seen at .?-4 month intervals in order to change the calcium hydroxide dressing. After 1 year tbere was no evidence ofthe dressing having been washed out through the perforations, and the surrounding structures showed marled repair. When probed from within the tooth, the apical area had been bridged with a firm, hard seal. The modified glass ionomer cement was used to obturate the canal. The irregular shape of the filling was observed on the radiograph (Fig. 3b). The periradicular tissues have cotitinued to heal, and the 2-year check-up continued to show healthy supporting structures. The tooth has been comfortable since treatment was started. Case 4
The next case is that of a 60-year-old man who had a large defect on the distal surface of the root ofthe maxillary left central incisor tooth. The tooth had been treated endodontically many years previously. The radiograph (Fig. 4a) shows the extent ofthe defect. To salvage the tooth, a surgical flap was raised and the area cleaned and prepared with curettes and burs. THe root was restored with
Ketac-Silver^ One month after remoial of tbe sutures, the periodontal tissues showed firm adaptation (Fig. 4b), despite a defect in the original position ofthe papilla. Since there was also a periapical defect, and the old root canal filling did not reach the apex, retreatment was instituted. .At the 6-month recall the radiograph (Fig. 4c) indicates that the bone was being repaired and was covering the reinforced glass ionomer cement. The papilla had also regenerated, as shown in Fig. 4d. Case .y
This patient was a 47-year-old man who had been referred because of discomfort involving the maxillary right central incisor tooth. .A periodontai pocket that communicated with a deep root surface defect could be probed from the buccaJ surface. The radiograph revealed an old root canal filling, and a metal post (Fig. 5a). A surgical flap was raised and the extent of the defect could be observed. The resorption extended deep enough to expose the metal post (Fig. 5b). The area was cleared of all soft tissue, and the defect was prepared with burs using the procedure adopted for any cavity preparation. The area was washed with hydrogen peroxide and further irrigated with local anaesthetic solution to remove debris. The area was dried with sterile sponges and restored with Ketac-Fil. The restoration hardened within 5 minutes, and w^as then contoured and polished ' Espe GmbH, Seefeld, Oberhay, W. Germany.
G. G. Stetpart
(c) (d) Fig. 4. (a) Obvious root defect in the maxillary left central incisor tooth, (h) Evidence of close tissue adaption 1 month after suture removal; the interdental papilla was missing, (c) Six months later there is obvious bone repair, (d) The interdental papilla has also regenerated. while being irrigated with local anaesthetic solution. The finished restoration is shown in Fig. 5c. One month after removal of the sutures, probing indicated a firm adaptation of the gingival tissues to the tooth surface. At the 6month recall the tissues appeared healthy, with some gingival recession (Fig. 5d). It has been suggested that a crown should be constructed to give the tooth maximum support and to cover the exposed glass ionomer cement. Gase 6 The last case is that of a JO-year-old woman with a history of trauma involving the maxillary right central incisor. The tooth was darker than the left central incisor. An attempt had been made to treat the tooth conventionally.
but calcification prevented access to the tooth apex. When the patient presented for treatment, there was some swelling in the apical area and the tooth was tender to percussion. A radiograph taken at that time showed calcification at the apex, and periradicular radiolucency (Fig. 6a). The swelling was reduced by the use of antibiotics. When all tenderness had subsided, a tissue flap was raised and the area curetted. A cavity was prepared at the apex extending to the root canal sealing material. T h e preparation was then carefully cleaned and irrigated with local anaesthetic solution. T h e prepared cavity was dried with absorbent paper points, and sealed with Ketac-Silver. Figure 6b shows the root end filling in position
Otass ionomer cements in endodonttcs
(c) (d) Fig- 5. (a) The maxillary anterior tooth showing an extensive root defect in a previously treated tooth, (b) The extent ofthe defect as observed after a tissue flap has been raised; the metal post in the root canal can also be seen, (c) Defect has been repaired with Ketac-Fil. (d) kt the 6-month check-up the tissues appear healthy, although there is some [:ins;-:\a[ recession; rebuilding with a crown was suggested.
Fig. 6. (a) Radiograph .showing a maxillary anterior tooth, in which the root canal filling does not reach the radiographic apex due to marked calcification; a periradicular defect is present, (b) Radiograph showing the Ketac-Siiver condensed and in contact with the old root canal filling, (c) Radiograph taken 14 months later, showing good bone healing.
C. G. Stewart
in contact with the old sealer. At the 1-year recall, the radiograph showed excellent bone repair (Fig. 6c). Discussion The cases presented demonstrate some areas where the glass ionomer cements were useful in treating endodontic problems. These materials are very well tolerated by the soft and hard tissues. The compatibility was noted when root endfillingsand/or resorpdons and perforations of the root were repaired with glass ionomer cement. The bone, as seen on follow-up radiographs, was able to grow over the repaired surfaces. The soft tissue, as illustrated in the regrowth ofthe papilla, illustrates the compatibility ofthe glass ionomers. The reinforced glass ionomers could be very useful in aiding the restoration of the crowns of multirooted teeth, when deep marginal cracks are present. The author has noted that such teeth, when restored with silver amalgam, have a greater tendency to fracture than teeth which do not have deep cracks. Since the glass ionomers bond to dentine and enamel, they may help to prevent fractures. The author has always suggested to referring dentists that a crown be constructed following root canal therapy, when deep marginal grooves are present, or if the tooth has many or large restorations. The modified glass ionomer has good radiopacity and excellent working time for endodontic procedures. It has been used alone, or in conjunction with gutta-percha, for obturation of the root canal. It is preferable to use the modified glass ionomer cement with guttapercha, since retreatment, if needed, could easily be performed. If the modified glass ionomer cement is used alone as the obturation material, retreatment could prove diflRcult or impossible. Conclusions Because ofthe tissue compatibility ofthe glass ionomer cements and their ability to bond to
dentine and enamel, they can he used in the treatment of many endodontic and restorative problems. The glass ionwner cements may in the future replace zinc oxide-eugenol root canal cements for obturation.
References BLACKMAN, R . , GROSS, M . & SELTZER, S . (1989)
An evaluation of the biocompatibiiity of a glass ionomer-silver cetnent in rat connective tissue. Joumat of Endodontics, 15,76-79. CzoNsrKOwSKY,
VAZQUEZ, J.A. (1985) Evaluation of an injection of thermoplasticized low-temperature guttapercha using radioactive isotopes. Journal of Endodontics, I t , 7 1 - 7 4 .
FORSTEN, L . (1977) Fluoride release from a glass ionomer cement. Scandinavian Journal ofDentat Research, 85, 503-504. MCLEAN, J.W. & WILSON, A.D. (1972) Sealing of
erosion cavities with a glass ionomer cement. Joumai ofDental Research, 51,1253 (abstract no. 62). PITT FORD, T.R. (1979) The leakage of root fillings using glass ionomer cement and other materials. British Dental Joumat, 146,273-278. SIMMONS, J. (1985) Ionomers for bases, cores and buildups. The Intemational Symposium on Glass Ionomers in Dentistry. STEWART, G . G . (1975) Calcium hydroxideinduced root healing. Joumat ofthe American Dental Association, 90,793-800. WILSON, A.D. & KENT, B.E. (1972). A new trans-
lucent cement for dentistry. British Dentat Joumat, 132,133-135. ZETTERQVIST, L . , ANNEROTH, G . & NORDENRAM,
A. (1987) Glass-ionomer cement as retrograde filling material. An experimental investigation in monkeys. Intemational Journal of Oral and Maxittofaciat Surgery, 16,459-464. ZMENER, O . & DOMINGUEZ, F.V. (1983) Tissue
response to a glass ionomer used as an endodontic cement. A preliminary study in dogs. Oral Surgery, Oral Medicine and Orat Pathology, 56, 198-205.