Microleakage in fissures sealed with resin or glass ionomer cement ROSANE COSTA OVREBO AND MAGNE RAADAL Department of Pedodontics, University of Bergen, Bergen, Norway
Ovrebo RC, Raadal M: Microleakage in Essures sealed with resin or glass ionomer cement. Scand J Dent Res 1990; 98: 66-9. Abstract - The purpose of this study was to investigate if microleakage occurs in fissures after being sealed wdth a glass ionomer cement [Fuji III). Ten pairs, of contralateral maxillary premolars, to be extracted for orthodontic reasons, were sealed in vivo. Glass ionomer cement was randomly used on one tooth and diluted composite on tbe contralateral. An air-poiishiog instrument was used for cleaning thefissuresbefore sealing them. After 14 days the sealant status, was recorded clinically and the teeth were extracted. They were placed in a 0.5% solution of methyl blue, subjected to a thermal cycling procedure, and finaliy sectioned. The sections were photographed in a, stereomicroscope, and two observers recorded the microleakage according to a scoring system. Three glass ionomer sealings were clinically recorded as missing, one partly missing, and six intact, while all the resin sealings were present. Extensive leakage was seen in all glass ionomer specimens with dye penetration throughout the material as well as a! the interface between cement and enamel. No leakage was seen in the composite specimens. Remnants of glass ionomer cement were observed in most of the sections from teeth which clinically seemed to have lost the sealing. This study indicates that Fuji HI is poorly retained in the fissures, and that the material permits leakage even when it is fully retained. The material may, however, prevent caries by release of fluorides, and the fact that remnants of cement were found in fissures which clinically seemed to have lost it, indicates that this may even occur in cases with loss of retention. Key words: fissure sealing; glass ionomer cement. Magne Raadal, Department of Pedodontics, School of Dentistry, Aarstadveien 17, N-5009 Bergen, Norway. Accepted for publication 11 June 1989.
Since glass ionomer cement was introduced in dentistry (1), it has mainly been used as a filling, cementing, and lining material. Only few reports have been published on glass ioBomer cements for fissure sealing (2-8), but it has been suggested that its fluoride
release (9, 10) and adherence to the enamel (11,12) may be suitable for the purpose, The capacity of a sealant to prevent microleakage into thefissureis important, since leakage may support a carious process underneath the sealant (13, 14). The purpose
MICROLEAKAGE IN SEALED FISSURES of this study was to investigate if leakage occurs after placement of a glass ionomer sealant.
Table 2 Microscopical sealant status of glass ionomer cement (GIC) and diluted composite resin (Resin) after 2 wk in the mouth GIC n=70
Present Partially present Missing
42 (60%) 16 (23%) 12 (17%)
80 (100%) 0^ (0%) 0 (0%)
Material and methods The plaeements of sealants were all done in vivo. Ten homologous pairs of maxillary premoiars, which were bound to extraction for orthodontic reasons, were used. The teeth were clinically sound and without restorations or previous fissure sealings. Before sealing them they were cleaned with an air-polishing instrument (Satelec) for 60 s and then thoroughly washed with water, dried, and isolated with cotton rolls (15). One tooth was chosen at random to be sealed with glass ionomer cement (Fuji III), and Ehe contralateral was sealed with diluted composite resin (Concise), The glass ionomer cement was handled according to the manufacturer's instructions, while the procedure for the diluted composite was according to a previously published routine (16), The teeth were left in the mouth for 14 days. Before extraction they were clinically examined, and the sealings were classified as present, partially present, or missing. After the extraction, the teeth were submitted to a thermocycling procedure between a cool (5°G±2) and a hot (60°C±2) solution of 0,5% methyl blue, 25 times, keeping them for 1 min in each solution. The roots were removed and the crowns embedded in resin blocks to prevent chipping of the material. Finally, the crowns were sectioned longitudinally in a buccolingual direction, and 4—6 sections of approximately I mm thickness were ob-
tained from each of the teeth. Sections were kept dry until they were analyzed. Each section was examined and photographed on both sides in a stereomicroscope ( x 4 magnification) , and the slides obtained were analyzed for dye penetration according to the following score system: Score 0: no dye penetration. Score 1:: dye penetration restricted to the outer half of the sealant. Score 2: dye penetration tO' the inner half of tbe sealant. Score 3: dye penetration into the underlying fis-
Residts The clinical examination revealed that the glass ionomer sealatit was present in six teeth, partially present in one, and totally missing
Tahle 1 Clinical sealant status of glass ixmomer emient (GIC) and diluted composite resin (Resin) after 2 wk in the mouth
GIC Present Partially present Missing
6 (60%) 1 (10%) 3 (30%) 10 (100%)
10 (100%) 0 (0%) 0 (0°4) 10 (100%)
SCORE I GLASS lONOMEe CEMENT
Fig. I. Bistribution of leakage scores (0 to 3) among sections with glass ionomer cement and resin sealants.
in three. All the resin sealings were present (Table 1). In the microscopical evaluation the glass ionomer cement was present in 60°/o of the sections, partially present in 23%, and missing in 17%. The composite re.sin was present in all sections (Table 2). AO teeth with glass, ionomer cement showed extensive leakage, with dye penetration throughout the material as well as at the interface hetween the cement and the enamel. However, only in cases with total loss of the eemetit was accumulation of dye seen in the bottom of the fissures (score 3). In 93% of the sections with composite resin there was no leakage at all, and only superficial leakage (score I) was observed in the other 7% (Figs. 1 and 2).
Fir 2. (Ground sections of Lcci;) .il'icr iKcirria. cydhig ill a dye solution. A, scciiuii oi' looLli scaled with glas5 ionomer cement showing dye penetration throughout Ehe matenal and at the interface between sealant a.nd enannel. B, section from a tooth in which the glass ionomer seal was recorded as clinically missing. Remnants of cement are still seen in the fissare (arrow). Leakage into the bottom of the fissure. G, section of tooth sealed with
It is considered to be important that a fissure sealant material is able to prevent microleakage (13, 14). This study indicates that Fuji III prevents leakage to a lesser degree than diluted composite resin. It seems to be a porous material, allowing microleakage both through it as well as at the interface between the enamel and the cement (Fig. 2.4). However, its porosity may also permit an easy leaching of fluoride ions to the surrounding tooth structure (9, 10). The present material is too small for definite conclusions about the retention of the two sealants. However, the fact that only 6 of the 10 glass ionomer sealants were fully retained indicates a poorer adhesion of this material, which is in accordance with other studies (3-6, 8).
diluted composite resin. Dye is restricted to surface of the seal, and no leakage is seen.
MIGROLEAKAGE IN SEALED FISSURES Under the microscope, remnants of the glass ionomer cement were observed in fissures where it seemed to be clinically missing (Fig. 2B). This indicates that the sealant may act as a fluoride-releasing material even in cases where it clinically seeois to have been lost. But how effective and how much fluoride is taken up by the enamel, are questions that need further study.
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