Journal of Oral Rehabilitation 2003 30; 753–757
A new silicon-based root canal sealer (Roekoseal-Automix) N . G E N C¸ O G L U * , C . T U¨ R K M E N * & R . A H I S K A L I †
*Department of Endodontics, Faculty of Dentistry,
Marmara University, Istanbul, Turkey and †Department of Pathology, Faculty of Medicine, Marmara University, Istanbul, Turkey
This study evaluated the new siliconbased sealer ‘Roekoseal-Automix’ (RSA) with respect to sealing, bonding capabilities and biocompatibility with rat subcutaneous connective tissue. For the microleakage study, 36 single rooted teeth were instrumented and 30 of these obturated with either Grossman’s sealer or RSA using lateral condensation technique (15 of each). Six teeth were not obturated and used as control group. For investigating bonding capability, 10 of the obturated roots with RSA and Grossman’s sealer were ground and split longitudinally and examined by scanning SUMMARY
Introduction One of the aims of endodontic treatment is to obturate the root canal system with an impervious biocompatible and dimensionally stable filling material (Nyguen et al., 1991). Gutta-percha cones with a sealer is now accepted as the most reliable method for obturating the root canal system. According to Grossman (1982), ideal root canal sealer should be capable of producing a bond between core material and the dentine of the root canal, prevent leakage, be non-toxic and enhance healing of periapical lesions. Although various kinds of materials like, zinc oxide eugenol (ZOE), resin cements, glass–ionomer and polyketone compounds have been used as a root canal sealer, the ideal root canal sealer has yet to be found. Recently, a silicon-based sealer Roekoseal-Automix (RSA) has been developed. It consists of polydimethyl siloxane, silicon oil, paraffin-base oil, hexachloroplatinic acid (catalyst), zirconium dioxide (radiopaque material) (RSA Brochure)*. It is supplied ready to use *Roeko GmbH Co, Langenau, Germany. ª 2003 Blackwell Publishing Ltd
electron microscopy (SEM). The RSA was found to seal significantly better than Grossman’s sealer. The SEM examination revealed a good bond between RSA and the dentine and between RSA and the gutta-percha. Tissue reaction was evaluated by injecting 0Æ1 mL RSA into the connective tissue of 21 male Albino–Wistar rats and observing at 24 h, 7 days and 30 days. Formation of a new granulation tissue with fibrous tissue adjacent to the material at 30 days. This study found that RSA performed well. KEYWORDS: dye penetration, Roekoseal, root canal sealer, silicon
in a dual-barrel syringe. With all synthetic rubbers – polysulphide, silicon, polyether or whatever the type – a homogeneous mix is essential for accuracy (Craig, 1989); RSA therefore comes in dual barrelled syringe form which forces equal quantities of base and catalyst through a removable static tip. The inside of the mixing tip contains a number of baffles that force the base and the catalyst to be folded over and over on each other as they are extruded. These systems have the advantage of uniformly dispensing and mixing the catalyst and the base in a way that results in fewer bubbles in the mixed material than with hand-spatulated mixes. Polydimethyl siloaxane has been used in dentistry for a long time especially in prosthodontics. Silicon-based impression materials are preferred because of low dimensional change (about 0Æ6–0Æ15%) and low water sorption. Silicon soft liners are suggested for use in patients with irritation of the denture-bearing mucosa (Phillips, 1981). Vulcanized or room temperature curing silicons are popular as maxillofacial materials for correcting facial defects resulting from cancer surgery, accident or congenital deformities because of good physical properties and ease of processing and matching to living
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N . G E N C¸ O G L U et al. facial tissue. Silicon-low temperature isotropic carbon alloy implants, usually placed on a metal or graphite substrate in the form of either a subperiosteal implant or an endosteal blade, have been found to be very biocompatible (Phillips, 1981). Although silicon tolerated well as an implant and can seal perfectly even in humid surroundings, few studies have been published on the silicon-based root canal sealer RSA. The aims of this study were to evaluate the sealing capacity of RSA by dye penetration, to observe the sealing and bonding capabilities of the sealer interface between the root filling and the canal wall using scanning electron microscopy (SEM) and to observe the response to RSA of subcutaneous rat connective tissue.
Six roots were unobturated and served as controls, three roots as positive controls, having open apices and the other three roots served as negative controls with the apices closed over with nail polish.
Microleakage tests All samples were placed into aqueous 2% methylene blue at 37 C for 48 h. After this period the teeth were grooved and split longitudinally. Two examiners measured the extent of dye penetration with a stereomicroscope. The mean values of the two measurements were recorded for each tooth and statistically analysed.
SEM examination
Materials and methods In this study, 46 single rooted teeth were used. The clinical crowns were removed and the roots were cleaned by immersion in 5Æ25% sodium hypochlorite for 24 h. Pulp tissue remnants were removed with barbed broach. Canal patency was determined by passing a size 15 file through the apical foramen and 1 mm was subtracted from these measurements to establish the working lengths. Apical preparations, followed by serially flaring the canals, accomplished the biomechanical preparation of each of the root canals. The roots were irrigated with 5Æ25% sodium hypochlorite before and after recapitulation with a size 60 master apical file. Then the roots were flared with Gates-Glidden burs to prepare the coronal third of the canals. Finally, each root was irrigated with 10 mL of 17% ethylenediaminetetraacetic acid. Then 36 roots were randomly divided into two experimental groups of 15 teeth each and six control (unobturated) teeth; 10 teeth were reserved for the SEM study. In the first group, the roots were obturated using the lateral condensation technique and Roekoseal-Automix*. A gutta-percha master cone† was fitted to within 0Æ5 mm of working length and RSA was placed into the root canal. A D11 spreader was used for lateral condensation of fine accessory gutta-percha cones. After complete canal obturation, the coronal gutta-percha was removed and zinc oxide-eugenol cement was used to seal the coronal orifice. In the second group, the teeth were obturated in the same way with laterally condensed gutta-percha and Grossman’s sealer. †
Dentsply, Maillefer, Balligues, Switzerland.
A JEOL JSM 5200‡ was used. The 10 teeth were obturated in the same way as in the RSA microleakage test group. Five teeth were split longitudinally and five ground transversely at different distances from the apex.
Biocompatibility tests Twenty-one male Albino–Wistar rats (15 test and six control) were anaesthetized by intra-peritoneal administration of sodium pentobarbital (0Æ026 g kg)1 body weight). The test rats were injected subcutaneously with 0Æ1 mL of RSA into their thoracic dorsal midline (Kolokouris et al., 1998). The test material was loaded into 1 mL sterile disposable plastic syringe with a 21-gauge needle. They were observed at 24 h, 7 and 30 days. At the end of each period seven animals (five test and two control) were killed by ether inhalation. The subcutaneous connective tissue around the injection site was surgically removed and immersed in 10% buffered formalin and routinely processed. Six to ten 6-l sections were prepared from each sample and stained with haematoxylin and eosin. All slides were coded and evaluated with the examiner being unaware of the source of the sample.
Results Mean linear apical dye leakage values for two groups are presented in Table 1. The negative control teeth showed no evidence of dye penetration. The positive ‡
JEOL, Tokyo, Japan.
ª 2003 Blackwell Publishing Ltd, Journal of Oral Rehabilitation 30; 753–757
SILICON-BASED SEALER (ROEKOSEAL) Table 1. Linear dye microleakage of each group Mean Group (n ¼ 15)
mm
s.d.
Range
Number of the teeth with no leakage
Roekoseal automix Grossman’s sealer
2Æ19 5Æ3
1Æ96 3Æ02
(0–6) (0–9)
2 1
control teeth showed dye penetration throughout the length of the canals. In the RSA group, the linear penetration of dye was 1Æ96 1Æ96 mm with two roots showing no leakage at all. In Grossman’s sealer group dye penetration was 5Æ3 3Æ02 mm and with one root showing no leakage at all. The difference was significant (t-test: P < 0Æ5). The SEM examination found close adaptation of the longitudinal specimens to the dentinal walls along the entire length of the root (Fig. 1a). The RSA penetration of some of the middle third dentinal tubulus was observed (Fig. 1b). In cross (horizontal) sections, however, the sealer was observed to fill the space between the gutta-percha cones and dentinal wall perfectly at each section (Fig. 2). In the 24-h samples, inflammatory infiltrate was either dense or predominant and composed mainly of polymorphonuclear leucocytes with few lymphocytes and sparse mast cells. Tissue response was limited to mild oedema and hyperaemia (Fig. 3). Seven-day samples had mild to moderate inflammatory reaction with a preponderance of giant cells with engulfed implant material. Capillary and fibroblastic proliferation were predominant. A fibrous capsule was beginning to form at the interface of the implant and the surrounding tissue (Fig. 4). Thirty-day samples showed a well-formed fibrous capsule surrounding the material. Capillary and fibroblastic proliferation seemed to continue and a mild lymphoplasmacytic-histiocytic infiltrate was seen in most of the samples (Fig. 5).
Discussion This study found the RSA to be a better sealer than Grossman’s sealer with regard to microleakage. Ebert and Petscheldt (1999) investigated the sealing ability of AH26 and RSA and found less leakage with RSA than AH26. There appear to be no other RSA microleakage studies in the literature. A number of studies of root canal sealers, measuring their sealing
Fig. 1. (a) Representative picture showing good adaptation of RSA to dentine in the middle third of the canal (Magnification ·750). (b) Representative picture showing to have plugged some dentinal tubules in higher magnification (Magnification ·1000).
ability by using the passage of bacteria, dye or radioisotope, have been conducted. Their findings, however, are not in good agreement. As in the present study, most of these studies used methylene blue dye for assessment of the sealing ability of both Grossman’s sealer and RSA, because the test can be easily performed without special facilities or instruments. These studies also used zinc oxide ⁄ eugenol sealers for comparison with new materials, because of their extensive use in practice. In theory, a good seal should be obtainable with sealers that adhere well to dentine and the core material (Orstavik, Eriksen & Beyer-Olsen, 1983). The SEM micrographs showed good adaptation between RSA and the root canal wall and also RSA had
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Fig. 2. Representative cross-section showing all spaces between the dentinal wall and the gutta-percha cones filled with the sealer (Magnification ·50).
Fig. 4. A 7-day sample with slight oedema, predominant capillary proliferation and mild mononuclear inflammatory infiltrate. Fibroblasts and a thin, discontinuous fibrous layer can be seen around the material (haematoxylin and eosin ·200).
penetrated into the some of the dentinal tubules in the middle third of the canal. In our previous study (Genc¸og˘lu, Samani & Gu¨nday, 1993), lateral condensation technique with Grossman’s sealer did not produce tubular penetration, but thermoplasticized gutta-percha techniques did. Many methods of testing biocompatibility of materials have been used with subcutaneous implantation of Teflon tubes filled with materials being one of the most common. In this study, however, subcutaneous injec-
tion was used in order to avoid the trauma caused by surgical incision (Kolokouris et al., 1998). A good filling material should be biocompatible and well tolerated by periapical tissues. This study found that subcutanous injection of RSA in rat tissue produced a mild to moderate inflammatory reaction at 24 h and 7 days but the reaction decreased and became chronic by the 30th day, with the implant being surrounded by a fibrous capsule. Willershausen et al. (2000), on the other hand, investigated the cytoxicity
Fig. 3. A 24-h sample shows a dense infiltrate of polymorphonuclear leucocytes surrounding the implantation material which is mostly washed away during processing but still seen as black and refractile fragments in some areas. There is oedema in the adjacent tissue (haematoxylin and eosin ·200).
Fig. 5. A 30-day sample shows a broad zone of collagenous fibronsis forming a pseudocapsule around the implant. Fibroblasts and histiocytes with particles of engulfed material are other features (haematoxylin and eosin ·200).
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SILICON-BASED SEALER (ROEKOSEAL) effects of MTA and RSA, titanium implants and found that MTA and RSA significantly reduced protein contact values. Lenander-Lumkari et al. (2000) investigated post-operative pain reaction in patients treated with either RSA or Grossman’s sealer and found no difference between the two groups. This study found the new silicon-based root canal sealer RSA, to have good potential as a root canal sealer and may well represent progress in the development of more biocompatible endodontic materials.
References CRAIG, R.G. (1989) Restorative Dental Materials, 8th edn, p. 547. C.V. Mosby Co, St. Louis, MO, USA. EBERT, J. & PETSCHELDT, A. (1999) Sealing ability of a new siliconbased sealer under different conditions. Journal of Dental Research, 78, Abstract No: 1715, 320. GENC¸OG˘LU, N., SAMANI, S. & GU¨NDAY, M. (1993) Dentinal wall adaptation of thermoplasticized gutta-percha in the absence or presence of smear layer: a SEM study. Journal of Endodontics, 19, 558. GROSSMAN, L.I. (1982) Endodontic Practice, 10th edn, p. 279. Lea & Febiger, Philadelphia.
KOLOKOURIS, I., KOTSAKI-KOVATSI, V.-P., ECONOMIDES, N., POULOPOULOS, A., ROZOS, G. & VLEMMAS, I. (1998) Influence of zinc oxide and eugenol sealer on concentration of zinc, calcium and copper in rat tissue. Endodontics and Dental Traumatology, 14, 210. LENANDER-LUMKARI, M., SIGURDSSON, A. & ORSTAVIK, D. (2000) Postoperative Pain Reactions Following Treatment and Root Filling Of Teeth With a New, Silicon-based Sealer. IADR 4th CED ⁄ NOF Joint Meeting 24 August, 2000. Warsaw, Poland. NYGUEN, T.N. (1991) Obturation of root canal system. In: Pathways of the Pulp, 5th edn (eds S. COHEN & R.C. BURNS), p. 193. C.V. Mosby Co, St. Louis, MO, USA. ORSTAVIK, D., ERIKSEN, H.M. & BEYER-OLSEN, E.M. (1983) Adhesive properties and leakage of root canal sealers in vitro. International Endodontic Journal, 16, 59. PHILLIPS, R.W. (1981) Skinner’s Science of Dental Materials, 8th edn, p. 137. W.B.Saunders, Philadelphia. WILLERSHAUSEN, B., HAGEDORN, B., SCHAFER, D. & BRISENO, B. (2000) Biocompatibility of ortograde and retrograde root canal filling materials. 57th Annual Session AAE, March 31–April 1, 2000, Honolulu, Hawaii. Correspondence: Dr Nimet Genc¸oglu, Department of Endodontics, Faculty of Dentistry, Marmara University, Bu¨yu¨k C¸iftlik sok. No: 6, 80200, Nisantas1, Istanbul, Turkey. E-mail:
[email protected]
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