Scand. J . Dent. Res. 1977: 85: 561-566 (Kty
w 1Icl5: drrrld /dlings: denld rnnferid~;cunning efccfron microrcopv)
Microstructure of inner surfaces on composite restorations related to filling procedure VIBEKE QVIST, JORCEN QVIST AND LAlLA JOHANNESSEN Institute and Clinicfor Cariology and Endodontics and Institutefor General Practice, Royal Dental College and Department flStructura1 Properties of Materials, Technical University of Denmar&, Copenhagen, Denmark
ABS'I'KAC~ - The inner surfaces of 40 Concise' restorations placed in uiuo on permanent niolars have been studied by scanning electron microscopy. Only grinding traces could be seen o n tillings from cavities which had not been etched, while the morphologic structure of the enamel and dentin was reflected o n fillings from acid-etched cavities. Application of low-viscous non-composite resin in the cavities before filling with the composite resin did not influence the enamel pattern on the fillings, while the amount of processes of resin corresponding to the dentinal tubules in etched cavities was significantly increased. In the discussion the difference in surface structure of the fillings is correlated to marginal leakage along similar restorations.
(Acceptedfor publication 1 1 June 1977)
Recently QWST & QVIST (1977) have shown that the frequency of cavities with iiiarginal leakage along Concisem fillings was significantly lower when the lowviscous resin, Concise" Enamel Bond, was applied to the walls of acid-etched cavities txlbre filling with the high-viscous coniposite material. Used alone, neither acid etching nor resin application showed that eltect. The purpose of the present scanning rlc~ctroiiiiiicroscope study is to show how the iiiner surfaces of Concise fillings are iiilluericed by the filling procedure. It might be possible thereby. to explain why the two procedures, etching and etching
plus resin, result in differences in niarginal leakage along the fillings.
Materialand methods The lillings were inade in 10 pairs of molars (18 and 28) with vital pulps. The teeth, which all had either an intact vestibular or lingual surlace, were to be extracted for orthodontic iuitl prophylactic reasons or o n account of coiiiplicated caries. Two circular, slightly iiiitlcwut cavities with diameter and depth of about 2 inin were prepared o n the vestibular or liiigual surlace of each tooth. The preparations wcre inade with an inverted-cone wolfram(" 'ti .I ~' l bur e in a KaVo Super All-air' 618 with waterspray. After preparation the cavities were
562
QVIST, QVIST AND JOHANNESSEN
cleaned with waterspray and dried with airblowing for 3-5 s. The four cavities in each pair ol’ teeth were treated and filled as follows with the low-viscous Concise” Enamel Bond System (“resin”, 3 M Co., batch No. 41632)and the high-viscous Concise” Cap-C-Rynge Systeiii (“Concise”, 3 M Co., batch No. 2129 2E). Group 1 - The cavities were filled with Concise, niechanically mixed. After application in the cavities, and before setting, excess filling iiiatcrial was removed with a carver and the surlice of the restorations was covered with wax. They were not trimmed. Group 2 - The cavity walls and bottom were covered with a layer of resin, and immediately lierealter the cavity was filled with Concise as in Group I . The resin compound of Catalyst Resin” and Universal Resin” was mixed according to the manufacturer’s directions. Group 3 - The cavity and the surrounding c.iiairiel were etched with Etching Liquid” (37% phosphoric acid) on a cotton pellet for 1 min, rinsrtl with waterspray, dried with air and filled with Concise. Group 4 - Etching was followed by application 01‘ resin and filling with Concise. The two cavities in each tooth were filled tlill~rently,either according to Groups 1 and 2 or t o Groups 3 and 4. Twenty minutes after the lilliiig the teeth were extracted and clcniiiieralized in 10% EDTA. During the clcnii~icralization the enamel dissolved and the lillings bccanie loose. The lillings were coated with a layer of about 100 pin carbon and a layer ofabout 150 pm gold in a vacuum evaporator and placed in a JSM-US scanning electron microscope (JEOL Co., Ltd., Tokyo). The fillings were examined o n the tiionitor of the microscope at linear niagnilications from x 60 to x 10,000 (voltage 25 kV). The four fillings in each pair of teeth were coinpared and graded according to reproduction of details and depth of the relief on the inner surlices. The number, size and shape of porosities/vacuoles were also evaluated. The microscopic examination was carried out without knowledge of which group the lilling originated from. The nonparametric Wilcoxon test for pair dilf‘erences (DIEM& LENTNER 1970)was used to determine whether the enamel and dentin relief was statistically significantly more distinct on fillings liorn Group 4 than o n tillings trom 0.10). The enamel-dentin junction was easily distinguished because of differences in structure. It was characteristic that the enamel prisms in this area had an irregular shape and orientation. Some tults could be seen arising from the rnamel-dentin junction and traversing the iiiner part of the enamel (Fig. 4). The inorphologic structure of the dentin was also reflected on the filling surfkces. Replica of the dentinal tubules were striated in longitudinally sectioned
SlJKFACE STRUCTURE OF FILLINGS
563
Fig. 1. Scanning electron micrograph of wall (w) and base (b) of a Concise filling with grinding traces and one great porosity/vacuole. x 75. Fzg. 2. Outer surface (s) and enamel wall (w) of a Concise filling from an acid-etched and resin-treated cavity. Prismatic structure of the enamel is reHected o n the filling. x 75. Fig. 3. Area from Fig. 2 at higher magnification. x 345. Fzg. 4. Enamel (e) - dentin (d)junction o n a Concise filling from an etched cavity. Several tufts are seen. x 220.
areas, and adjacent to cross-sectioned dentin the fillings showed bubbles (Fig. 5 ) . Moreover, six fillings from Group 3 and nine from Group 4 had a varied number 01' regular processes about 1-2pm in diameter and about 10-20lm in length (Fig. 7). In a few instances they were 200 pm in length. These processes, which
in some cases showed ramifications corresponding to branching of tubules (Fig. 81, were mainly seen at the deep part of the fillings at the junction between the walls and the base. In all cases the processes had a pulpal direction (Fig. 61, expressive of never having been placed on the occlusal part of the filling. Two fillings
564
QVIST, QVIST AND JOHANNESSEN
Fig. 5. Replica of longitudinal (I) and cross-sectioned (c) dentinal tubules on a Concise filling from an etched cavity. x 735. Fig. 6. Base and wall of a Concise filling from an etched and resin-treated cavity. The filling has a high number of resin processes corresponding to dentinal tubules. x 85. Fig. 7. Area with resin processes from Fig. 6 at higher magnification. x 1,495. Fig. 8. Resin processes with ramifications from dentinal part of a Concise filling from an etched cavity. x 3,660.
from Group 4 had a high number of processes, giving the dentin part of the fillings a bearded appearance (Fig. 6). Corresponding to these two fillings, the dentin relief evaluated by occurrence of bubbles and processes was far better than that observed on the Group 3 fillings
trom the same pairs. In the remaining eight pairs the relief was evaluated best on five fillings from Group 4 and on two fillings from Group 3. In one pair no difference could be seen. The statistical analysis showed that the dentin relief of the fillings in Group 4 was significantly
SURFACE STRUCTURE O F FILLINGS
565
01' loading and/or changes in temperature (Qvis-r 1975, JORGENSEN,MATONO & 1976). This may explain why porosities/vacuoles were seen o n the walls SHIMOKOBE or base in seven and five cases bacteria were seen in almost all the respectively. As in Groups 1 and 2, cavities tilled as in Groups 1 and 2 (QVIST iiuiiibcr, size and shape varied. In Group & QVIST 1977). These results are in & ANDREWS 4 none of the fillings contained great accordance with HEMBREE aiid/or many porosities/vacuoles while (1976b), who investigated the in vivo this was the case on five fillings from occurrence of marginal leakage along Group 3. All in all, when resin was used lilliiigs made according to the Nuva@tlie occurrence of porosities/vacuoles was system. The enamel part of the fillings from Icss marked. etched cavities exhibited no significant tli1li.rence in the relief in the present wries. This corresponds to findings by Discuuion JORGENSEN & SHIMOKOBE(1975). 111 the last few years much research has Processes of filling material into the dealt with prevention of marginal leakage tleiitinal tubules have earlier been along composite resin restorations. The ohserved (e.g. BARNES 1975, LIPTON & acid .etch technique, introduced by SMITH 1977). These authors point out that BIIONOCORE(1955), has been widely used, resin processes could be demonstrated hut this method does not seem to prevent only occasionally because they often t tie occurrence of marginal leakage along liactured during the preparation for conventional butt joint restorations (e.g. SEM-examination. By the method used in V O J I N O V I ~ ,NYBORG & BRANNSTROM tlie present investigation it was possible to 1973, GALAN,MONDELLI& CORADAZZIpreserve these processes. The quantitative 1976, HEMBREE & ANDREWS 1976a, QVIST occurrence to some extent could thereby & QVlST 1977). be estimated, but the amount of processes The use of an intermediary layer of a rcwiaining o n the surfaces can still be low-viscous, non-composite resin between somewhat less than originally. However, the etched cavity and the composite filling there were significantly more processes on has been recommended, and research has lillings from Group 4 than on fillings shown that it is hereby possible to reduce lrorn Group 3. Comparing this with the the percentage of restorations with dillerent occurrence of bacteria beneath leakage including bacterial penetration similar fillings (QVIST & QVIST 1977) it (GALAN et al. 1976, HEMBREE & ANDREWS s e e m likely that marginal leakage along 1976b, ROULET 1976, FORSTEN 1977, lillings in composite resins as Concise QVIST& QVIST 1977). cannot be prevented exclusively by In the present SEM-investigation, the inechanical interlocking of the fillings to only structure found on the inner surfaces the etched enamel, as no difference in the of' fillings from non-etched cavities was replica of the etched enamel were seen grinding traces, precluding a mechanical between fillings from the two groups. bond between the fillings and the sur- Bonding to the dentin part of the cavities rounding tooth. Because of this a plastic lrom a number of dentinal processes deformation of the fillings in the oral appears also to be necessary for prevenenvironment is possible as a consequence tion of leakage in the oral environment. iiiore distinct than in Group 3 (P= 0.05). Ot' the 20 fillings in Groups 3 and 4
566
QVIST, QVIST A N D JOHANNESSEN
11' bonding to both the enamel a n d (Iriitin part of a cavity is necessary, an intr.rlI,ediary base Inaterial be used t o insulate the base in a cavity which is to
Ix etched and filled with composite resin. Such a treatment is, however, clinically it has been shown that irlrlevant pulpal reactions do not occur beneath composite restorations without marginal leakage. ncknowled~ent The authors wish to express to tlicir gratitude FLEMMING KRAGH' Department of Structural Properties of Materials, The Technical University of Denmark, for skillful technical instruction and assistance with the scanning microscope.
References BARNES, I. E.: The marginal adaptation of composite resins. An investigation using the scanning electron microscope. In: AMERONGEN, A. J. VAN,DIPPEL,H. W., SPANAUF, A. J. & VRIJHOEF, M. M. A. (eds.): Proceedings of the international symposium on amalgam and tooth-coloured restorative materials, 1975, pp. 129-157. BIIONOCORE, M. G.: A simple method of increasing the adhesion of acrylic filling inaterials to enamel surfaces. J. Dent. Res. 1955: 34: 849-853. DIEM, K. & LENTNER, C.: Documents G e b . S&nt$c tables, 7th ed. J. R. Geigy SA., Basel, 1970, pp. 128, 157-159, 192. FORSTEN, L.: Effect of different factors on the marginal seal of composites. I.A.D.R.
Address : Vibeke Qvist Institute and Clinicfor Cariology and Endodontics Royal Dental College 4 (Iniversitetsparhen DK-2100Copenhagen t) Denmark ~
Abstract. J . Dent. Res. 1977: 56: Special Issue A: A 149GAL.AN1 J.*J R . 9 MONDELLIv J. CORADmZIv J. L.: Marginal leakage of two composite restorative systems. J . Dent. Res. 1976: 5 5 : 74-76. H t . M H R E E , J. H., JR. & ANDREWS,J. T.: Microleakage of several acid-etch composite resin systems: A laboratory study. Oper. I)ent. 1976a:1: 91-97, J. H., J R . & ANDREWS, J. T.: In situ rvaluation of marginal leakage using an ultraviolet-light-activated resin system. J . Am. Dent, Assoc. 1976b: 92: 414-418. JOKGENSEN, K. D. & SHIMOKOBE, H.: Adaptation of resinous restorative materials to acid etched enamel surfaces. Scand. J . I)ent. 1975:83: 31-36. JORGENSEN, K. D., MATONO,R. & SHIMOKOBE, H.: Deformation of cavities and resin fillings in loaded teeth. Scand. J . Dent. Res. 1976: 84: 46-50. LIYI'ON,S. D. & SMITH,D. C.: Evaluation of the bonding of cervical restorative riiaterials. I.A.D.R. Abstract. J. Dent. Res. 1977: 56: Special Issue A: A 152. QVIST, V.: Pulp reactions in human teeth to tooth colored tilling materials. Scand. J . Dent. Res. 1975: 83: 54-66. QVIST,V. & QVIST,J.: Marginal leakage along Concise' in relation to filling procedure. Scand. J. Dent. Res. 1971: 85: 305-312. ROIILET, J. F.: Untersuchung uber den Randschluss von Kornposits in vivo. Schweiz. Monatsschr. Zahnheilhd. 1976: 86: 699-7 10. VOJINOVIC, O., NYBORG, H. & BRANNSTROM, M.: Acid treatment of cavities under resin lillings: Bacterial growth in dentinal tubules and pulpal reactions. J. Dent. Res. 1973: 5 2 : 1189-1 193.
w 1Icl5: drrrld /dlings: denld rnnferid~;cunning efccfron microrcopv)
Microstructure of inner surfaces on composite restorations related to filling procedure VIBEKE QVIST, JORCEN QVIST AND LAlLA JOHANNESSEN Institute and Clinicfor Cariology and Endodontics and Institutefor General Practice, Royal Dental College and Department flStructura1 Properties of Materials, Technical University of Denmar&, Copenhagen, Denmark
ABS'I'KAC~ - The inner surfaces of 40 Concise' restorations placed in uiuo on permanent niolars have been studied by scanning electron microscopy. Only grinding traces could be seen o n tillings from cavities which had not been etched, while the morphologic structure of the enamel and dentin was reflected o n fillings from acid-etched cavities. Application of low-viscous non-composite resin in the cavities before filling with the composite resin did not influence the enamel pattern on the fillings, while the amount of processes of resin corresponding to the dentinal tubules in etched cavities was significantly increased. In the discussion the difference in surface structure of the fillings is correlated to marginal leakage along similar restorations.
(Acceptedfor publication 1 1 June 1977)
Recently QWST & QVIST (1977) have shown that the frequency of cavities with iiiarginal leakage along Concisem fillings was significantly lower when the lowviscous resin, Concise" Enamel Bond, was applied to the walls of acid-etched cavities txlbre filling with the high-viscous coniposite material. Used alone, neither acid etching nor resin application showed that eltect. The purpose of the present scanning rlc~ctroiiiiiicroscope study is to show how the iiiner surfaces of Concise fillings are iiilluericed by the filling procedure. It might be possible thereby. to explain why the two procedures, etching and etching
plus resin, result in differences in niarginal leakage along the fillings.
Materialand methods The lillings were inade in 10 pairs of molars (18 and 28) with vital pulps. The teeth, which all had either an intact vestibular or lingual surlace, were to be extracted for orthodontic iuitl prophylactic reasons or o n account of coiiiplicated caries. Two circular, slightly iiiitlcwut cavities with diameter and depth of about 2 inin were prepared o n the vestibular or liiigual surlace of each tooth. The preparations wcre inade with an inverted-cone wolfram(" 'ti .I ~' l bur e in a KaVo Super All-air' 618 with waterspray. After preparation the cavities were
562
QVIST, QVIST AND JOHANNESSEN
cleaned with waterspray and dried with airblowing for 3-5 s. The four cavities in each pair ol’ teeth were treated and filled as follows with the low-viscous Concise” Enamel Bond System (“resin”, 3 M Co., batch No. 41632)and the high-viscous Concise” Cap-C-Rynge Systeiii (“Concise”, 3 M Co., batch No. 2129 2E). Group 1 - The cavities were filled with Concise, niechanically mixed. After application in the cavities, and before setting, excess filling iiiatcrial was removed with a carver and the surlice of the restorations was covered with wax. They were not trimmed. Group 2 - The cavity walls and bottom were covered with a layer of resin, and immediately lierealter the cavity was filled with Concise as in Group I . The resin compound of Catalyst Resin” and Universal Resin” was mixed according to the manufacturer’s directions. Group 3 - The cavity and the surrounding c.iiairiel were etched with Etching Liquid” (37% phosphoric acid) on a cotton pellet for 1 min, rinsrtl with waterspray, dried with air and filled with Concise. Group 4 - Etching was followed by application 01‘ resin and filling with Concise. The two cavities in each tooth were filled tlill~rently,either according to Groups 1 and 2 or t o Groups 3 and 4. Twenty minutes after the lilliiig the teeth were extracted and clcniiiieralized in 10% EDTA. During the clcnii~icralization the enamel dissolved and the lillings bccanie loose. The lillings were coated with a layer of about 100 pin carbon and a layer ofabout 150 pm gold in a vacuum evaporator and placed in a JSM-US scanning electron microscope (JEOL Co., Ltd., Tokyo). The fillings were examined o n the tiionitor of the microscope at linear niagnilications from x 60 to x 10,000 (voltage 25 kV). The four fillings in each pair of teeth were coinpared and graded according to reproduction of details and depth of the relief on the inner surlices. The number, size and shape of porosities/vacuoles were also evaluated. The microscopic examination was carried out without knowledge of which group the lilling originated from. The nonparametric Wilcoxon test for pair dilf‘erences (DIEM& LENTNER 1970)was used to determine whether the enamel and dentin relief was statistically significantly more distinct on fillings liorn Group 4 than o n tillings trom 0.10). The enamel-dentin junction was easily distinguished because of differences in structure. It was characteristic that the enamel prisms in this area had an irregular shape and orientation. Some tults could be seen arising from the rnamel-dentin junction and traversing the iiiner part of the enamel (Fig. 4). The inorphologic structure of the dentin was also reflected on the filling surfkces. Replica of the dentinal tubules were striated in longitudinally sectioned
SlJKFACE STRUCTURE OF FILLINGS
563
Fig. 1. Scanning electron micrograph of wall (w) and base (b) of a Concise filling with grinding traces and one great porosity/vacuole. x 75. Fzg. 2. Outer surface (s) and enamel wall (w) of a Concise filling from an acid-etched and resin-treated cavity. Prismatic structure of the enamel is reHected o n the filling. x 75. Fig. 3. Area from Fig. 2 at higher magnification. x 345. Fzg. 4. Enamel (e) - dentin (d)junction o n a Concise filling from an etched cavity. Several tufts are seen. x 220.
areas, and adjacent to cross-sectioned dentin the fillings showed bubbles (Fig. 5 ) . Moreover, six fillings from Group 3 and nine from Group 4 had a varied number 01' regular processes about 1-2pm in diameter and about 10-20lm in length (Fig. 7). In a few instances they were 200 pm in length. These processes, which
in some cases showed ramifications corresponding to branching of tubules (Fig. 81, were mainly seen at the deep part of the fillings at the junction between the walls and the base. In all cases the processes had a pulpal direction (Fig. 61, expressive of never having been placed on the occlusal part of the filling. Two fillings
564
QVIST, QVIST AND JOHANNESSEN
Fig. 5. Replica of longitudinal (I) and cross-sectioned (c) dentinal tubules on a Concise filling from an etched cavity. x 735. Fig. 6. Base and wall of a Concise filling from an etched and resin-treated cavity. The filling has a high number of resin processes corresponding to dentinal tubules. x 85. Fig. 7. Area with resin processes from Fig. 6 at higher magnification. x 1,495. Fig. 8. Resin processes with ramifications from dentinal part of a Concise filling from an etched cavity. x 3,660.
from Group 4 had a high number of processes, giving the dentin part of the fillings a bearded appearance (Fig. 6). Corresponding to these two fillings, the dentin relief evaluated by occurrence of bubbles and processes was far better than that observed on the Group 3 fillings
trom the same pairs. In the remaining eight pairs the relief was evaluated best on five fillings from Group 4 and on two fillings from Group 3. In one pair no difference could be seen. The statistical analysis showed that the dentin relief of the fillings in Group 4 was significantly
SURFACE STRUCTURE O F FILLINGS
565
01' loading and/or changes in temperature (Qvis-r 1975, JORGENSEN,MATONO & 1976). This may explain why porosities/vacuoles were seen o n the walls SHIMOKOBE or base in seven and five cases bacteria were seen in almost all the respectively. As in Groups 1 and 2, cavities tilled as in Groups 1 and 2 (QVIST iiuiiibcr, size and shape varied. In Group & QVIST 1977). These results are in & ANDREWS 4 none of the fillings contained great accordance with HEMBREE aiid/or many porosities/vacuoles while (1976b), who investigated the in vivo this was the case on five fillings from occurrence of marginal leakage along Group 3. All in all, when resin was used lilliiigs made according to the Nuva@tlie occurrence of porosities/vacuoles was system. The enamel part of the fillings from Icss marked. etched cavities exhibited no significant tli1li.rence in the relief in the present wries. This corresponds to findings by Discuuion JORGENSEN & SHIMOKOBE(1975). 111 the last few years much research has Processes of filling material into the dealt with prevention of marginal leakage tleiitinal tubules have earlier been along composite resin restorations. The ohserved (e.g. BARNES 1975, LIPTON & acid .etch technique, introduced by SMITH 1977). These authors point out that BIIONOCORE(1955), has been widely used, resin processes could be demonstrated hut this method does not seem to prevent only occasionally because they often t tie occurrence of marginal leakage along liactured during the preparation for conventional butt joint restorations (e.g. SEM-examination. By the method used in V O J I N O V I ~ ,NYBORG & BRANNSTROM tlie present investigation it was possible to 1973, GALAN,MONDELLI& CORADAZZIpreserve these processes. The quantitative 1976, HEMBREE & ANDREWS 1976a, QVIST occurrence to some extent could thereby & QVlST 1977). be estimated, but the amount of processes The use of an intermediary layer of a rcwiaining o n the surfaces can still be low-viscous, non-composite resin between somewhat less than originally. However, the etched cavity and the composite filling there were significantly more processes on has been recommended, and research has lillings from Group 4 than on fillings shown that it is hereby possible to reduce lrorn Group 3. Comparing this with the the percentage of restorations with dillerent occurrence of bacteria beneath leakage including bacterial penetration similar fillings (QVIST & QVIST 1977) it (GALAN et al. 1976, HEMBREE & ANDREWS s e e m likely that marginal leakage along 1976b, ROULET 1976, FORSTEN 1977, lillings in composite resins as Concise QVIST& QVIST 1977). cannot be prevented exclusively by In the present SEM-investigation, the inechanical interlocking of the fillings to only structure found on the inner surfaces the etched enamel, as no difference in the of' fillings from non-etched cavities was replica of the etched enamel were seen grinding traces, precluding a mechanical between fillings from the two groups. bond between the fillings and the sur- Bonding to the dentin part of the cavities rounding tooth. Because of this a plastic lrom a number of dentinal processes deformation of the fillings in the oral appears also to be necessary for prevenenvironment is possible as a consequence tion of leakage in the oral environment. iiiore distinct than in Group 3 (P= 0.05). Ot' the 20 fillings in Groups 3 and 4
566
QVIST, QVIST A N D JOHANNESSEN
11' bonding to both the enamel a n d (Iriitin part of a cavity is necessary, an intr.rlI,ediary base Inaterial be used t o insulate the base in a cavity which is to
Ix etched and filled with composite resin. Such a treatment is, however, clinically it has been shown that irlrlevant pulpal reactions do not occur beneath composite restorations without marginal leakage. ncknowled~ent The authors wish to express to tlicir gratitude FLEMMING KRAGH' Department of Structural Properties of Materials, The Technical University of Denmark, for skillful technical instruction and assistance with the scanning microscope.
References BARNES, I. E.: The marginal adaptation of composite resins. An investigation using the scanning electron microscope. In: AMERONGEN, A. J. VAN,DIPPEL,H. W., SPANAUF, A. J. & VRIJHOEF, M. M. A. (eds.): Proceedings of the international symposium on amalgam and tooth-coloured restorative materials, 1975, pp. 129-157. BIIONOCORE, M. G.: A simple method of increasing the adhesion of acrylic filling inaterials to enamel surfaces. J. Dent. Res. 1955: 34: 849-853. DIEM, K. & LENTNER, C.: Documents G e b . S&nt$c tables, 7th ed. J. R. Geigy SA., Basel, 1970, pp. 128, 157-159, 192. FORSTEN, L.: Effect of different factors on the marginal seal of composites. I.A.D.R.
Address : Vibeke Qvist Institute and Clinicfor Cariology and Endodontics Royal Dental College 4 (Iniversitetsparhen DK-2100Copenhagen t) Denmark ~
Abstract. J . Dent. Res. 1977: 56: Special Issue A: A 149GAL.AN1 J.*J R . 9 MONDELLIv J. CORADmZIv J. L.: Marginal leakage of two composite restorative systems. J . Dent. Res. 1976: 5 5 : 74-76. H t . M H R E E , J. H., JR. & ANDREWS,J. T.: Microleakage of several acid-etch composite resin systems: A laboratory study. Oper. I)ent. 1976a:1: 91-97, J. H., J R . & ANDREWS, J. T.: In situ rvaluation of marginal leakage using an ultraviolet-light-activated resin system. J . Am. Dent, Assoc. 1976b: 92: 414-418. JOKGENSEN, K. D. & SHIMOKOBE, H.: Adaptation of resinous restorative materials to acid etched enamel surfaces. Scand. J . I)ent. 1975:83: 31-36. JORGENSEN, K. D., MATONO,R. & SHIMOKOBE, H.: Deformation of cavities and resin fillings in loaded teeth. Scand. J . Dent. Res. 1976: 84: 46-50. LIYI'ON,S. D. & SMITH,D. C.: Evaluation of the bonding of cervical restorative riiaterials. I.A.D.R. Abstract. J. Dent. Res. 1977: 56: Special Issue A: A 152. QVIST, V.: Pulp reactions in human teeth to tooth colored tilling materials. Scand. J . Dent. Res. 1975: 83: 54-66. QVIST,V. & QVIST,J.: Marginal leakage along Concise' in relation to filling procedure. Scand. J. Dent. Res. 1971: 85: 305-312. ROIILET, J. F.: Untersuchung uber den Randschluss von Kornposits in vivo. Schweiz. Monatsschr. Zahnheilhd. 1976: 86: 699-7 10. VOJINOVIC, O., NYBORG, H. & BRANNSTROM, M.: Acid treatment of cavities under resin lillings: Bacterial growth in dentinal tubules and pulpal reactions. J. Dent. Res. 1973: 5 2 : 1189-1 193.
