Marginal adaptation of nine commercial intermediate resins H. Chigira* K. Itoh $. Wakumoto Department of Operative Dentistry School of Dentistry Showa University 2-1-1 Kitasenzoku, Ohta-Ku Tokyo 145, Japan Received March 13, 1990 Accepted December 25, 1990 *To whom correspondence and reprint requests should be addressed Dent Mater 7:103-106, April, 1991
Abstract-The bonding efficacy of nine commercially availableintermediate resins was examined by measuring the maximum contraction gap of a lightactivated composite in a cylindrical cavity of human dentin. With only one exception, the marginal adaptation of the composite improved significantly when the intermediate resins were combined with an experimental dentin cleaning system of the neutralized 0.5 mol/L EDTA and a dentin primer composed of a 35% aqueous solution of either hydroxyethyl methacrylate (HEMA) or glyceryl methacrylate (GM). Complete marginal adaptation was obtained with four tested materials when dentin was pre-treated with EDTA and GM.
~
t is widely known that the bonding between the resin composite and the dentin is affected significantly by the combination of the dentin cleanser, dentin primer, and the intermediate resin used (Manabe et al., 1991). In spite of the improvement of dentin bonding with the developm e n t of dentin primers (Munksgaard and Asmussen, 1984; Bowen et al., 1982; Hayakawa et al., 1988; Tagami et al., 1987), only a few systems are able to overcome the contraction stress of the resin composite (Yanagawa et al., 1988; Chigira et al., 1989). Furthermore, this contraction stress can result in a marginal gap between the resin and the dentin cavity wall as a result of the bonding insufficiency (Asmussen and J¢rgensen, 1972; Munksgaard et al., 1984). A significantly improved bonding efficacy of an aqueous solution of hydroxyethyl methacrylate (HEMA) and glyceryl methacrylate (GM) as a dentin primer when combined with a commercial intermediate resin containing phosphate ester has been reported (Itoh and Wakumoto, 1987; Chigira et al., 1989). The purpose of the present study was to evaluate the bonding efficacy of commercial intermediate resins with and w i t h o u t e x p e r i m e n t a l cleansing and primers by measuring the polymerization contraction gap formation of a light-activated resin composite in extracted human teeth. MATERIALS AND METHODS The intermediate resins tested are listed in Table 1. A cylindrical cavity approximately 3 mm in diameter and 1.5 mm in depth was prepared with a No. 61 steel bur mounted on a low-speed cutting machine in the exposed dentin of the proximal surface of an extracted human molar after the enamel was ground with wet carborundum paper (220-grit). The intact human
teeth prepared were extracted within three months of use and stored in tap water in a refrigerator at 4°C. In the first series, the cavity wall was treated with the dentin cleanser and dentin primer or the etching agent according to the manufacturer's instructions, except for the TLB, for which no pre-treatment was indicated. The intermediate resins were then applied with a small sponge pellet. In the CPB, PLB, SB2, and TLB groups, the intermediate resin was irradiated for 20 s with a visible-light unit (Quick Light, Morita, Kyoto, Japan). After the excess intermediate resins were removed with a blast of compressed air, the light-activated composite (Silux Plus Universal, 3M, St. Paul, MN, USA) was slightly overfilled in the cavity. The surface of the composite was pressed on a glass plate mediated with a plastic matrix and irradiated for 40 s. After the specimens were stored in tap water for 10 min, the cavity margin was exposed on wet carborundum paper (1000-grit) and polished on a linen cloth with an alumina slurry (0.3 ~m). The width of the maximum contraction gap was measured with a screw m i c r o m e t e r (Eyepiece Digital, Leitz, Wetzlar, Germany) mounted on the ocular lens of a light microscope (Metaloplan, Leitz, Wetzlar, Germany) at a magnification of 1024. The maximum contraction was presented as a percentage of the cavity diameter, as described in our previous paper (J~rgensen et al., 1985). This calculation was considered as the bonding efficacy. In the next series, the cavity wall was cleaned for 60 s with 0.5 mol/L EDTA neutralized with a NaOH solution. After the tooth was rinsed and dried, one of the two experimental dentin p r i m e r s - t h e aqueous solution of 35% hydroxyethyl methacrylate (HEMA) (E. Merck, Darmstadt, Germany) or glyceryl methacrylate
Dental Materials~April 1991 103
TABLE1 INTERMEDIATE RESINS TESTED Code CNB
Brand ClearfilNew Bond
Manufacturer Kuraray Co., Osaka, Japan
CPB
Clearfil Photo Bond
Kuraray Co., Osaka, Japan
GL4 PLB
Gluma 4 Pyrofil Light Bond
Bayer AG, Leverkusen, Germany Sankin Industry Co., Ltd., Osaka, Japan
RB3
Lee Pharmaceuticals, South El Monte, CA, USA
SB2 SBD
Restobond 3 Sealer Scotchbond 2 Superbond D Liner
3M, St. Paul, MN, USA Sun Medical Co., Ltd., Kyoto, Japan
TLB VS
Tokuso Light Bond Visar Seal
Tokuyama Soda Co., Ltd., Yamaguchi, Japan Den-Mat Co., Santa Maria, CA, USA
(GM)-was applied for 60 s, and the cavity was completely dried with a strong blast of compressed air. The GM was prepared as reported in our previous paper (Chigira et al., 1989). The intermediate resin application, composite filling, and the gap width measurement were performed by the same method as described in the first series. For the control, ten specimens were added in which the application of the intermediate resin was omitted. Ten specimens for each group were prepared, for a total of 290 specimens. RESULTS
Table 2 presents the results of maximum gap formation when the methTABLE2 MAXIMUM CONTRACTION OF SILUX PLUS IN CYLINDRICAL DENTIN CAVITY USING METHODS OF COMMERCIAL PRODUCTS Code Maximum Contraction SBD 0.057% ( 0 - 0.134)[4] SB2 0.118% (0.068 - 0.270) [0] GL4 0.173% ( 0 - 0.320) [1] TLB 0.181% (0.045 - 0.289) [0] RB3 0.249% (0.101 - 0.466) [0] CPB 0.272% (0.180 - 0.347) [0] PLB 0.289% (0.181 - 0.397) [0] CNB 0.406% (0.275 - 0.525) [0] VS 0.515% (0.162 - 0.950)[0] n=10. Mean value of maximum contraction and range in (). Number of gap-free specimens in [ ]. The intermediate resins were applied after pretreatment of the cavity according to the manufacturer's instructions. Values joined by a line are not significantly different by one-way analysis of variance by ranks (p
Abstract-The bonding efficacy of nine commercially availableintermediate resins was examined by measuring the maximum contraction gap of a lightactivated composite in a cylindrical cavity of human dentin. With only one exception, the marginal adaptation of the composite improved significantly when the intermediate resins were combined with an experimental dentin cleaning system of the neutralized 0.5 mol/L EDTA and a dentin primer composed of a 35% aqueous solution of either hydroxyethyl methacrylate (HEMA) or glyceryl methacrylate (GM). Complete marginal adaptation was obtained with four tested materials when dentin was pre-treated with EDTA and GM.
~
t is widely known that the bonding between the resin composite and the dentin is affected significantly by the combination of the dentin cleanser, dentin primer, and the intermediate resin used (Manabe et al., 1991). In spite of the improvement of dentin bonding with the developm e n t of dentin primers (Munksgaard and Asmussen, 1984; Bowen et al., 1982; Hayakawa et al., 1988; Tagami et al., 1987), only a few systems are able to overcome the contraction stress of the resin composite (Yanagawa et al., 1988; Chigira et al., 1989). Furthermore, this contraction stress can result in a marginal gap between the resin and the dentin cavity wall as a result of the bonding insufficiency (Asmussen and J¢rgensen, 1972; Munksgaard et al., 1984). A significantly improved bonding efficacy of an aqueous solution of hydroxyethyl methacrylate (HEMA) and glyceryl methacrylate (GM) as a dentin primer when combined with a commercial intermediate resin containing phosphate ester has been reported (Itoh and Wakumoto, 1987; Chigira et al., 1989). The purpose of the present study was to evaluate the bonding efficacy of commercial intermediate resins with and w i t h o u t e x p e r i m e n t a l cleansing and primers by measuring the polymerization contraction gap formation of a light-activated resin composite in extracted human teeth. MATERIALS AND METHODS The intermediate resins tested are listed in Table 1. A cylindrical cavity approximately 3 mm in diameter and 1.5 mm in depth was prepared with a No. 61 steel bur mounted on a low-speed cutting machine in the exposed dentin of the proximal surface of an extracted human molar after the enamel was ground with wet carborundum paper (220-grit). The intact human
teeth prepared were extracted within three months of use and stored in tap water in a refrigerator at 4°C. In the first series, the cavity wall was treated with the dentin cleanser and dentin primer or the etching agent according to the manufacturer's instructions, except for the TLB, for which no pre-treatment was indicated. The intermediate resins were then applied with a small sponge pellet. In the CPB, PLB, SB2, and TLB groups, the intermediate resin was irradiated for 20 s with a visible-light unit (Quick Light, Morita, Kyoto, Japan). After the excess intermediate resins were removed with a blast of compressed air, the light-activated composite (Silux Plus Universal, 3M, St. Paul, MN, USA) was slightly overfilled in the cavity. The surface of the composite was pressed on a glass plate mediated with a plastic matrix and irradiated for 40 s. After the specimens were stored in tap water for 10 min, the cavity margin was exposed on wet carborundum paper (1000-grit) and polished on a linen cloth with an alumina slurry (0.3 ~m). The width of the maximum contraction gap was measured with a screw m i c r o m e t e r (Eyepiece Digital, Leitz, Wetzlar, Germany) mounted on the ocular lens of a light microscope (Metaloplan, Leitz, Wetzlar, Germany) at a magnification of 1024. The maximum contraction was presented as a percentage of the cavity diameter, as described in our previous paper (J~rgensen et al., 1985). This calculation was considered as the bonding efficacy. In the next series, the cavity wall was cleaned for 60 s with 0.5 mol/L EDTA neutralized with a NaOH solution. After the tooth was rinsed and dried, one of the two experimental dentin p r i m e r s - t h e aqueous solution of 35% hydroxyethyl methacrylate (HEMA) (E. Merck, Darmstadt, Germany) or glyceryl methacrylate
Dental Materials~April 1991 103
TABLE1 INTERMEDIATE RESINS TESTED Code CNB
Brand ClearfilNew Bond
Manufacturer Kuraray Co., Osaka, Japan
CPB
Clearfil Photo Bond
Kuraray Co., Osaka, Japan
GL4 PLB
Gluma 4 Pyrofil Light Bond
Bayer AG, Leverkusen, Germany Sankin Industry Co., Ltd., Osaka, Japan
RB3
Lee Pharmaceuticals, South El Monte, CA, USA
SB2 SBD
Restobond 3 Sealer Scotchbond 2 Superbond D Liner
3M, St. Paul, MN, USA Sun Medical Co., Ltd., Kyoto, Japan
TLB VS
Tokuso Light Bond Visar Seal
Tokuyama Soda Co., Ltd., Yamaguchi, Japan Den-Mat Co., Santa Maria, CA, USA
(GM)-was applied for 60 s, and the cavity was completely dried with a strong blast of compressed air. The GM was prepared as reported in our previous paper (Chigira et al., 1989). The intermediate resin application, composite filling, and the gap width measurement were performed by the same method as described in the first series. For the control, ten specimens were added in which the application of the intermediate resin was omitted. Ten specimens for each group were prepared, for a total of 290 specimens. RESULTS
Table 2 presents the results of maximum gap formation when the methTABLE2 MAXIMUM CONTRACTION OF SILUX PLUS IN CYLINDRICAL DENTIN CAVITY USING METHODS OF COMMERCIAL PRODUCTS Code Maximum Contraction SBD 0.057% ( 0 - 0.134)[4] SB2 0.118% (0.068 - 0.270) [0] GL4 0.173% ( 0 - 0.320) [1] TLB 0.181% (0.045 - 0.289) [0] RB3 0.249% (0.101 - 0.466) [0] CPB 0.272% (0.180 - 0.347) [0] PLB 0.289% (0.181 - 0.397) [0] CNB 0.406% (0.275 - 0.525) [0] VS 0.515% (0.162 - 0.950)[0] n=10. Mean value of maximum contraction and range in (). Number of gap-free specimens in [ ]. The intermediate resins were applied after pretreatment of the cavity according to the manufacturer's instructions. Values joined by a line are not significantly different by one-way analysis of variance by ranks (p
