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ISSN (Print) 1013-9052
EISSN 1658-3558
The Saudi Dental Journal,
P.O. Box 52500,
Riyadh 11563,
Kingdom of Saudi Arabia
P.O. Box 52500,
Riyadh 11563,
Kingdom of Saudi Arabia
| Tel. |
966-1-467-7328 |
| Fax. |
933-1-467-7308 / 966-1-467-7534 |
| Email |
saudidj@ksu.edu.sa |
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Microleakage evaluation of four tooth colored restorative systems
This study evaluated mlcroleakage of four tooth colored restorative
systems. Conquest Crystal/Bond 1, FloRestore/Tenure Quick with
fluoride, Compogiass/Syntac and Ketac - Molar Apllcap which are: a
composite resin, a flowable composite, a compomer and a glass ionomer
cement respectively.
Class V-like circular preparations (3 mm diameter, 1.5 mm deep) were prepared at the cemento-enamel junction of 40 extracted human premolar teeth. Ten cavities in each group were restored with one of the materials. Following 72 hours storage in a 37°C water bath, the restored teeth were thermocycled for 500 cycles between 5°C and 55°C for one minute in each cycle. Mlcroleakage was assessed by dye penetration using 0.2% basic fuchsin dye. The resu Its we reanalyzed using the Kruskal-Wal 11 s Test. No micro Ieakage was evident at the enamel margins as well as in the gingival margins. None of the systems evaluated were able to prevent mlcroleakage at the gingival margin (cementum) completely, but these systems were effective In minimizing mlcroleakage at the enamel restorative interface.
The ingress of acids, ions, enzymes
and their products through gaps at the tooth restorative interface has been
termed microleakage.1 This phenomenon may predispose a tooth to
discoloration at cavity margins, recurrent decay and pulpal inflammation.2,3 Post-operative sensitivity
has also been reported as a result of microleakage.4,5 One reason suggested for
microleakage is the formation of a gap at the tooth-restoration interface by
the polymerization shrinkage of a composite resin.4,6-8 Since the introduction of composite materials in dentistry, continual improvement has been made in their properties. Microleakage, however, still occupies a major focus of researchers trying to improve the longevity of composite restorations.9,10,2 Manufacturers have developed bonding agents in an attempt to control leakage at the tooth-restoration interface. The acid-etching technique has reduced microleakage at the enamel-composite interface.9-11 Inspite of the introduction of a number of dentin bonding agents, microleakage is still often reported, where the cavosurface margin is placed on dentin or cementum.8,12,-15 The purpose of this in vitro study was to evaluate microleakage associated with four commercially available tooth colored restorative systems.
Forty non-carious extracted human premolar teeth were used in this
experiment. The teeth were stored
in 0.1% thymol
solution at room temperature after their extraction. The
teeth were cleaned by removing any remaining soft tissue and stored in a
physiological saline solution until use. To effectively eliminate microleakage
at the root apices, the following procedures were performed. The apices of the
roots were removed with a separating disc. Class I preparations were made at
the cut apical root surfaces with an inverted cone carbide bur. Two coats of
Copal cavity varnish were applied to these preparations and the specimens were
restored with Dispersalloy amalgam (Caulk/Dentsply, Milford, DE).
Immediately prior to the cavity preparation, the tooth surfaces were cleaned with pumice and water using a rubber cup in a slow speed handpiece. A Class V-like circular cavity preparation was placed on the buccal surface of each tooth with a No. 330 bur. The preparations were located at the cemento-enamel junction. Approximately fifty percent of the cavity margins were placed in enamel and the other 50% were placed in the cementum. The preparation was approximately 3 mm in diameter and 1.5 mm deep. Ten teeth were randomly selected for each restorative system. The following systems were used in accordance with manufacturer's directions: Conquest Crystal/ Bond 1 (Jeneric/Pentron Inc. Walligford, CT.), FloRestore/Tenure Quick with fluoride (DenMat, Inc. Santa Maria, CA.), Compoglass/Syntac (Ivoclar North America, Inc. Amherst, NY) and Ketac-Molar Aplicap (ESPE America, Norristown, PA). These systems are, respectively: a composite resin, a flowable composite, a compomer and a glass ionomer cement. Following placement and finishing, all specimens were stored in distilled water at 37°C for 72 hours. The teeth in each group were thermocycled for 500 cycles between water baths of 5°C and 55°C Immersion time was approximately 30 seconds in each bath. Following thermocycling, the entire tooth was coated with a nail polish with the exception of the restoration and approximately 1 mm around it. The restorations were evaluated for marginal microleakage by immersion in 0.2% basic Fuchsine dye (Fisher Scientific, Fairlawn, NJ) for 24 hours. Following removal from the solution, the teeth were rinsed with tap water. Each tooth was mounted in cold cure acrylic resin using a plastic mold. The restored area was protected by a sticky wax followed by clear nail polish to avoid dye dissolution during the mounting procedure. Each tooth was sectioned longitudinally through the center of the restoration with a diamond blade (Isomet, low speed saw, Buehler Ltd. Evanston, IL. The specimens were examined under a microscope at 25X magnification by 2 different examiners. The specimens were scored according to the following criteria: 0 = no dye penetration 1 = the dye penetrated less than or up to one half of the cavity depth 2 = the dye penetrated more than one half of the cavity depth but not extending to the axial wall 3 = the dye penetrated to involve the axial wall Each specimen produced two segments after sectioning, both of which were evaluated and the higher score was included in the results. No difference in scoring was detected among the two examiners.
The average microleakage scores at the enamel margins are listed
in Table 1. No microleakage was evident at the enamel margins of Ketac-Molar
Aplicap restorations and 9 of the Compoglass restorations. Nearly half of the
Conquest Crystal and FlorRestore restorations showed leakage.
The average microleakage scores at the dentin/cementum margins are shown in Table 2. Leakage was present at the gingival margins in all treatment groups. The results were analyzed using the non-parametric Kruskal-Wallis Test.16 There was no significant difference among the enamel margins (P > 0.05). There was also no significant difference in gingival margins either in all the four groups (P > 0.05). Conquest Crystal/Bond 1 showed the least number of zero scores.
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