Journal of Investigative and Clinical Dentistry (2011), 2, 63–69
ORIGINAL ARTICLE Dental Biomaterials
Posterior resin composite restorations with or without resin-modified, glass-ionomer cement lining: a 1-year randomized, clinical trial Danuchit Banomyong1, Choltacha Harnirattisai1 & Michael F. Burrow2 1 Department of Operative Dentistry, Faculty of Dentistry, Mahidol University, Bangkok, Thailand 2 Melbourne Dental School, the University of Melbourne, Melbourne, Victoria, Australia
Keywords clinical trial, glass-ionomer cement lining, posterior resin composite, self-etching adhesive, total-etch adhesive. Correspondence Dr Danuchit Banomyong, Department of Operative Dentistry, Faculty of Dentistry, Mahidol University, Bangkok, Thailand, 6 Yothee Road, Rajthevee, Bangkok 10400, Thailand. Tel: +66-2-203-6461-2 Fax: +66-2-203-6463 Email: [email protected] Received 20 May 2010; accepted 29 August 2010. doi: 10.1111/j.2041-1626.2010.00036.x
Abstract Aim: To investigate the effect of resin-modified, glass-ionomer cement lining on the quality of posterior resin composite restorations, bonded with a twostep, total-etch or self-etching adhesive, at 1 year. Methods: Patients with 1–4 moderate-to-deep, primary occlusal caries in molars were informed and recruited. A total of 110 composite restorations were placed in 75 participants, with one of four restorative procedures: (a) bonded with a total-etch adhesive (Single Bond 2); (b) lined with glassionomer cement (Fuji Lining LC), and then bonded with total-etch adhesive; (c) bonded with a self-etching adhesive (Clearfil SE Bond); and (d) lined with glass-ionomer cement, and then bonded with self-etching adhesive. Results: At 1 year, 57 patients (86 restorations) attended the recall. Each of the restorations was evaluated and scored from 1 (clinically excellent) to 5 (clinically poor) using the following criteria: (a) patient satisfaction; (b) fracture and retention; (c) marginal adaptation; (d) recurrent caries; and (e) post-operative sensitivity. At 1 year, the qualities of the restorations were not significantly affected by the placement of glass-ionomer cement lining, regardless of the adhesive used (P > 0.05). Most of the restorations were scored 1 for all criteria. Conclusions: The benefit of placing a glass-ionomer cement liner in resin composite restoration is questionable.
Introduction Currently, resin composites are commonly used for restorations in anterior and posterior teeth. In a deep cavity, a liner/base, such as glass-ionomer cement (GIC), is usually placed on dentin at the pulpal floor in order to protect the pulp from any possible irritation.1 In addition, placing a GIC liner can reduce total polymerization shrinkage stress of the resin composite by reducing the amount of the restorative material, as well as acting like a stressabsorption layer.2 Moreover, bonding to deep dentin under simulated pulpal pressure is a challenge for resinbased adhesives, especially a total-etch adhesive. This is a result of the increase in dentin permeability and increased dentin surface wetness from dentinal fluid flow.3 In ª 2010 Blackwell Publishing Asia Pty Ltd
contrast, GIC is a water-based cement that is able to bond chemically to deep dentin with much less technique sensitivity.3 Therefore, restorations with less gap formation or microleakage are anticipated if a GIC lining is used. As previously mentioned, it seems that the application of a GIC lining might be useful for resin composite restorations, yet it has been reported that the incidence of internal gap formation under resin composite restorations with a GIC lining is likely to be greater than that of restorations without a lining.4,5 Thus, the internal seal along the cavity floor of a lined restoration might be negatively affected,4 and its longevity could deteriorate. Until recently, it has been claimed that placing a GIC lining might reduce post-operative sensitivity associated with resin composite restorations.6 It was found that in 63
Posterior composite and glass-ionomer lining
non-carious teeth, the pulpal inflammation of the teeth restored with the resin composite with a GIC lining was reported to be less than that of the unlined restored teeth.7 Nevertheless, the results from clinical trials are not clear cut; one study showed the benefit of resin-modified GIC lining in reducing post-operative sensitivity,8 while another study did not.9 For these reasons, the benefit of placing a GIC lining beneath resin composite restorations remains controversial. The purpose of this randomized, clinical trial was to investigate the effect of a GIC lining on the quality of posterior resin composite restorations, bonded with either a total-etch or self-etching adhesive, at 1 year. The null hypothesis was there is no significant difference in the restoration quality among the trial groups with and without a GIC lining, regardless of the type of adhesive used. Materials and methods The trial was conducted following the Consolidated Standards of Reporting Trials Statement10,11 and the Recommendations for Conducting Controlled Clinical Studies of Dental Restorative Materials12 from the Postgraduate Clinic of the Faculty of Dentistry, Mahidol University, Bangkok, Thailand. The project was approved by the committee of Mahidol University, Thailand. Recruitment of participants Patients aged 18–40 years, who had at least one moderate-to-deep occlusal caries lesion (2–4 mm in depth, but no exposure of the pulp) in a first or second maxillary/ mandibular molar, were recruited. Each participant was informed of the nature of the study, and consent was obtained. The sample size was calculated using Minitab 14 statistical software (Minitab, State College, PA, USA). The minimum sample size of each group was calculated, following these input conditions: power of 0.9 and P = 0.05; they increased to at least 26 restorations per group to compensate for participant dropouts during follow up. The inclusion and exclusion criteria are listed in Table 1. Participants were not enrolled if they had any medical problems or if they were unable to return for follow-up appointments. The criteria for the investigated tooth are also described in the table. In brief, the teeth used in the trial were diagnosed as having moderateto-deep primary occlusal caries without other defects, and had at least one opposing tooth. Additionally, teeth were excluded if either the cavity depth after caries removal was less than 2 mm or a pulp exposure or near pulp exposure, in which calcium hydroxide application was indicated. 64
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Table 1. Inclusion and exclusion criteria used for the recruitment of participants Inclusion criteria Dental––an investigated tooth: • Clinically diagnosed as moderate-to-deep occlusal caries; no caries detected on other surfaces • With no signs or symptoms of pulpal and periapical disease • Might exhibit pre-operative sensitivity, but was relieved immediately after stimulus removal • Had at least one antagonist tooth with occlusal contact more than 50% of the occlusal surface • Had healthy or mildly-inflamed gingival tissues, without gingival recession/alveolar bone loss Exclusion criteria Patients with one of the following medical conditions: • Psychological disorders • Neurological diseases • Temporo-mandibular disorders • Pregnancy or breast feeding • Taking any analgesic or anti-inflammatory drugs regularly • Allergy to materials used in this trial Dental––an investigated tooth: • With previous restoration(s) and/or tooth surface loss (attrition, erosion, abrasion, or abfraction) • Diagnosed as ‘‘cracked tooth syndrome’’ • That has received orthodontic treatment within the previous 3 months
In each case, patient details were recorded. To maintain privacy and confidentiality, a serial number was assigned to replace each patient’s name. Medical and dental histories were taken. The investigated tooth, supporting periodontal tissues, and existence of the opposing tooth/teeth were thoroughly examined. A pre-operative, radiographic examination using a bite-wing radiograph was routinely taken to rule out proximal caries. Restorative procedures The field of operation was isolated with the application of a rubber dam if moisture control was difficult to achieve. Otherwise, gauze/cotton rolls and the use of a saliva ejector/high-velocity evacuator were employed for moisture control. If requested, a local anaesthetic, 2% mepivacaine hydrochloride with 1:100 000 epinephrine (Scandonest 2% special, Septodent, Saint-Maur-des-Fosses Cedex, France), was administered to control tooth pain/sensitivity during the procedure. Dental caries was removed using a conservative preparation. To gain the entrance to the carious lesion, undermined enamel was removed using a round or fissure, high-speed diamond bur (Intensiv SA, Grancia, Switzerland) under an air–water coolant. ª 2010 Blackwell Publishing Asia Pty Ltd
D. Banomyong et al.
Posterior composite and glass-ionomer lining
In an attempt to guide the operator in the step of caries removal, dentine caries was stained with a caries detector dye (caries detector; Kuraray Medical, Okayama, Japan) for 10 sec and rinsed according to the manufacturer’s instruction. The stained surface was removed using slowspeed, round steel burs (Emil Lange, Engelskirchen, Germany), which were of similar size to the caries lesions, and spoon excavators (Sci-Dent, Algonquin, IL, USA) until the dentine was stained pale pink and was relatively hard. In this study, the operator attempted to remove most of the soft, carious dentine while keeping the affected and/or sclerotic dentine as much as possible. After caries removal, cavity size and depth at the greatest dimensions from cavity margins were measured (in mm) using a periodontal probe (PCP-UNC 15; Hu-Friedy, Chicago, IL, USA). One-to-four restorations were randomly allocated to a treatment-planned tooth by one operator (DB) according to a computer-generated, blocking, randomization list. Each participant was unaware of the restoration type placed; however, blinding the operator to which intervention was allocated was not possible. The prepared cavity was randomly restored using one of the following restorative procedures: (a) Single Bond 2 (SB2): bonded with a two-step, total-etch adhesive (SB2) without lining; (b) SB2/Fuji Lining LC (FLC): lined with a resin-modified GIC liner (FLC), and then bonded with total-etch adhesive; (c) Clearfil SE Bond: bonded with a two-step, selfetching adhesive (Clearfil SE Bond) without lining; and (d) SE/FLC: lined with the GIC liner, and then bonded with self-etching adhesive. Details of the restorative materials used are listed in Table 2, and all materials were applied according to the manufacturers’ instructions. In the GIC-lining groups, the lining was applied in 0.5– 1 mm thickness over the entire dentin surface. The lined and/or bonded cavity was incrementally filled ( 0.05). Discussion In this study, the survival rate of occlusal resin composite restorations at 1 year was almost 100%. Thus, occlusal caries can be successfully restored with nano-filled resin composites bonded with a two-step, total-etch or selfetching adhesive, regardless of the presence of a GIC lining, which corresponds with the results of another clinical study.13 Only one restoration was replaced because of chronic post-operative sensitivity, which is possibly due to a critical error in the bonding procedure of the totaletch adhesive.14 Furthermore, the other two restorations were later removed and included in occluso-proximal restorations because of proximal caries, and one restored tooth was extracted due to an unknown periodontal problem. Therefore, these restorations were not true failures within the selected evaluation criteria. Post-operative sensitivity is associated with posterior resin composite restorations, depending on the size and depth of the restored cavity.15,16 In fact, it is one of the negative outcomes when a dentine adhesive is not used properly and can usually be prevented by using the ª 2010 Blackwell Publishing Asia Pty Ltd
adhesive carefully in every step, following the manufacturers’ instructions.9 Usually, post-operative sensitivity can be relieved and become asymptomatic over time without any further extensive treatment.16,17 However, the sensitivity can sometimes persist and become chronic so that a replacement of the restoration is needed. It seems that the application of a GIC lining does not affect the incidence of short-term post-operative sensitivity.9 Furthermore, using a total-etch adhesive does not seem to provide a greater chance of post-operative sensitivity occurrence in comparison to a self-etching adhesive.9,17,18 It is believed that placing a GIC liner can improve the quality of the restoration by reducing polymerization shrinkage stress, and subsequently allowing superior marginal adaptation to be obtained.2,19 On the contrary, the result of this clinical trial indicated that no significant difference in marginal adaptation between the restorations with or without a resin-modified GIC lining at 1 year occurred. Unfortunately, no other clinical study investigating restorations with or without lining was found in a literature search. Similarly, the marginal adaptation of the restoration bonded with a total-etching adhesive was not superior to that bonded with a self-etching adhesive, which corresponds with results of other studies.20,21 The occlusal cavities in this study had entirely enamel margins, and the bond to the prepared enamel with the self-etching adhesive was comparable to that with the total-etch adhesive.22 This is in contrast with a laboratory study that showed better marginal adaptation in restorations bonded with a total-etch adhesive.23 In fact, the marginal defects usually need time to form and be detected, so a follow-up evaluation over a longer term is required. Controversially, the formation of recurrent caries might or might not relate to a marginal defect or leakage.24,25 However, if the marginal defect is large enough to become a site for plaque retention, recurrent caries is likely to occur.26 Theoretically, restorations with a GIC 67
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lining might have better marginal adaptation (less marginal leakage) than the restorations without a lining.19 Due to the outcome of this 1-year trial, placing a GIC lining did not improve the marginal quality of restorations in the short term. In this study, minor marginal defects were found in just a few restorations, which could be corrected by refinishing and repolishing. Clinically, any excess of restorative material might be unintentionally left at the cavity margin after finishing/polishing,27 which might eventually chip off during function and then create small marginal defects. In comparing the total-etch and self-etching adhesive, the adhesion/bond strength to uncut enamel of the former is generally better than that of the latter.28 Nevertheless, adhesion to cut enamel of a twostep, self-etching adhesive is comparable to that of a total-etching adhesive28 so that the marginal adaptation and recurrent caries of a restoration bonded with these two-step adhesives were not significantly different. The placement of a liner/base might negatively affect the overall strength of the restoration, since the lining material is weaker than the restorative material.29,30 Interestingly, it should be further investigated whether the overall strength of the restoration is reduced by the application of a liner/base of the different thicknesses (thin lining or thick base). Furthermore, internal gap formation between lining material and dentin, which is probably caused by the retraction force generated from the
References 1 Ritter AV, Edward JSJ. Current restorative concepts of pulp protection. Endodontic Topics 2003; 5: 41– 8. 2 Ferracane JL. Buonocore Lecture. Placing dental composites–a stressful experience. Oper Dent 2008; 33: 247–57. 3 Banomyong D, Palamara JEA, Burrow MF, Messer HH. Effect of dentin conditioning on dentin permeability and micro-shear bond strength. Eur J Oral Sci 2007; 115: 502–9. 4 Banomyong D, Palamara JEA, Messer HH, Burrow MF. Sealing ability of occlusal resin composite restoration using four restorative procedures. Eur J Oral Sci 2008; 116: 571–8. 5 Peliz MIL, Duarte S Jr, Dinelli W. Scanning electron microscope analysis of internal adaptation of materials
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9
polymerization shrinkage stress of the resin composite, has been reported to occur at the pulpal floor of the restoration.4,5 This internal gap could reduce the retention of the restoration. Nevertheless, the fracture and retention rates of the posterior resin composite restorations in this study were not negatively influenced by the placement of the GIC lining, and were independent of the adhesive used. In conclusion, the null hypotheses were accepted. No significant differences in all evaluated criteria were found among the restorations with and without a resin-modified GIC lining, regardless of the adhesive used (total-etch or self-etching adhesive) at 1 year. Moderate-to-deep occlusal cavities might be restored successfully with a nanofilled resin composite bonded with the two-step adhesives, regardless of whether a GIC liner is placed or not. In the short term, the GIC lining did not affect the quality of an occluso-posterior resin composite restoration with surrounding enamel margins. However, the GIC lining could provide the benefit of remineralizing carious-affected dentine,31 which could not be observed and are beyond the scope of this study. Moreover, the survival rate and quality of the restoration should be further observed over a longer term to confirm these short-term findings. In addition, the benefit of GIC lining in occluso-proximal restoration, with enamel or dentine gingival margin, should be also investigated.
used for pulp protection under composite resin restorations. J Esthet Restor Dent 2005; 17: 118–28. Christensen GJ. Preventing postoperative tooth sensitivity in class I, II and V restorations. J Am Dent Assoc 2002; 133: 229–31. Costa CAD, Giro EMA, do Nascimento ABL, Teixeira HM, Hebling J. Short-term evaluation of the pulpo-dentin complex response to a resin-modified glass-ionomer cement and a bonding agent applied in deep cavities. Dent Mater 2003; 19: 739–46. Akpata ES, Sadiq W. Post-operative sensitivity in glass-ionomer versus adhesive resin-lined posterior composites. Am J Dent 2001; 14: 34–8. Banomyong D, Harnirattisai C, Messer HH, Burrow MF. Effect of glass-ionomer lining on postoperative sensitivity in occlusal cavities restored with resin composite- a
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randomized clinical trial. Oper Dent 2009; 34: 648–55. Boutron I, Moher D, Altman DG, Schulz KF, Ravaud P. Extending the CONSORT statement to randomized trials of nonpharmacologic treatment: explanation and elaboration. Ann Intern Med 2008; 148: 295–309. Altman DG, Schulz KF, Moher D et al. The revised CONSORT statement for reporting randomized trials: explanation and elaboration. Ann Intern Med 2001; 134: 663–94. Hickel R, Roulet J-F, Bayne S et al. Recommendations for conducting controlled clinical studies of dental restorative materials. Science Committee Project 2/98–FDI World Dental Federation study design (Part I) and criteria for evaluation (Part II) of direct and indirect restorations including onlays and partial crowns. J Adhes Dent 2007; 9(Suppl 1): 121–47. Palaniappan S, Bharadwaj D, Mattar DL, Peumans M, Van Meerbeek B,
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Lambrechts P. Three-year randomized clinical trial to evaluate the clinical performance and wear of a nanocomposite versus a hybrid composite. Dent Mater 2009; 25: 1302–14. Frankenberger R, Kramer N, Petschelt A. Technique sensitivity of dentin bonding: effect of application mistakes on bond strength and marginal adaptation. Oper Dent 2000; 25: 324–30. Auschill TM, Koch CA, Wolkewitz M, Hellwig E, Arweiler NB. Occurrence and causing stimuli of postoperative sensitivity in composite restorations. Oper Dent 2009; 34: 3–10. Briso ALF, Mestrener SR, Delicio G et al. Clinical assessment of postoperative sensitivity in posterior composite restorations. Oper Dent 2007; 32: 421–6. Browning WD, Blalock JS, Callan RS et al. Postoperative sensitivity: a comparison of two bonding agents. Oper Dent 2007; 32: 112–7. Casselli DSM, Martins LRM. Postoperative sensitivity in class I composite resin restorations in vivo. J Adhes Dent 2006; 8: 53–8. Chuang SF, Jin YT, Lin TS, Chang CH, Garcia-Godoy F. Effects of lining materials on microleakage and internal voids of Class II resin-
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based composite restorations. Am J Dent 2003; 16: 84–90. Manhart J, Chen HY, Hickel R. Three-year results of a randomized controlled clinical trial of the posterior composite QuiXfil in class I and II cavities. Clin Oral Invest 2009; 13: 301–7. Bekes K, Boeckler L, Gernhardt CR, Schaller HG. Clinical performance of a self-etching and a total-etch adhesive system––2-year results. J Oral Rehabil 2007; 34: 855–61. Shimada Y, Senawongse P, Harnirattisai C, Burrow MF, Nakaoki Y, Tagami J. Bond strength of two adhesive systems to primary and permanent enamel. Oper Dent 2002; 27: 403–9. Swanson TK, Feigal RJ, Tantbirojn D, Hodges JS. Effect of adhesive systems and bevel on enamel margin integrity in primary and permanent teeth. Pediatric Dent 2008; 30: 134–40. Cenci MS, Pereira-Cenci T, Cury JA, ten Cate JM. Relationship between gap size and dentine secondary caries formation assessed in a microcosm biofilm model. Caries Res 2009; 43: 97–102. Heintze SD. Systematic reviews: I. The correlation between laboratory tests on marginal quality and bond
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strength. II. The correlation between marginal quality and clinical outcome. J Adhes Dent 2007; 9: 77–106. Totiam P, Gonzalez-Cabezas C, Fontana MR, Zero DT. A new in vitro model to study the relationship of gap size and secondary caries. Caries Res 2007; 41: 467–73. Kramer N, Reinelt C, Richter G, Petschelt A, Frankenberger R. Nanohybrid vs. fine hybrid composite in class II cavities: clinical results and margin analysis after four years. Dent Mater 2009; 25: 750–9. Senawongse P, Sattabanasuk V, Shimada Y, Otsuki M, Tagami J. Bond strengths of current adhesive systems on intact and ground enamel. J Esthet Restor Dent 2004; 16: 107–15; discussion 16. Mongkolnam P, Tyas MJ. Light-cured lining materials: a laboratory study. Dent Mater 1994; 10: 196–202. Banditmahakun S, Kuphasuk W, Kanchanavasita W, Kuphasuk C. The effect of base materials with different elastic moduli on the fracture loads of machinable ceramic inlays. Oper Dent 2006; 31: 180–7. Ngo HC, Mount G, Mc Intyre J, Tuisuva J, Von Doussa RJ. Chemical exchange between glass-ionomer restorations and residual carious dentine in permanent molars: an in vivo study. J Dent 2006; 34: 608–13.
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ORIGINAL ARTICLE Dental Biomaterials
Posterior resin composite restorations with or without resin-modified, glass-ionomer cement lining: a 1-year randomized, clinical trial Danuchit Banomyong1, Choltacha Harnirattisai1 & Michael F. Burrow2 1 Department of Operative Dentistry, Faculty of Dentistry, Mahidol University, Bangkok, Thailand 2 Melbourne Dental School, the University of Melbourne, Melbourne, Victoria, Australia
Keywords clinical trial, glass-ionomer cement lining, posterior resin composite, self-etching adhesive, total-etch adhesive. Correspondence Dr Danuchit Banomyong, Department of Operative Dentistry, Faculty of Dentistry, Mahidol University, Bangkok, Thailand, 6 Yothee Road, Rajthevee, Bangkok 10400, Thailand. Tel: +66-2-203-6461-2 Fax: +66-2-203-6463 Email: [email protected] Received 20 May 2010; accepted 29 August 2010. doi: 10.1111/j.2041-1626.2010.00036.x
Abstract Aim: To investigate the effect of resin-modified, glass-ionomer cement lining on the quality of posterior resin composite restorations, bonded with a twostep, total-etch or self-etching adhesive, at 1 year. Methods: Patients with 1–4 moderate-to-deep, primary occlusal caries in molars were informed and recruited. A total of 110 composite restorations were placed in 75 participants, with one of four restorative procedures: (a) bonded with a total-etch adhesive (Single Bond 2); (b) lined with glassionomer cement (Fuji Lining LC), and then bonded with total-etch adhesive; (c) bonded with a self-etching adhesive (Clearfil SE Bond); and (d) lined with glass-ionomer cement, and then bonded with self-etching adhesive. Results: At 1 year, 57 patients (86 restorations) attended the recall. Each of the restorations was evaluated and scored from 1 (clinically excellent) to 5 (clinically poor) using the following criteria: (a) patient satisfaction; (b) fracture and retention; (c) marginal adaptation; (d) recurrent caries; and (e) post-operative sensitivity. At 1 year, the qualities of the restorations were not significantly affected by the placement of glass-ionomer cement lining, regardless of the adhesive used (P > 0.05). Most of the restorations were scored 1 for all criteria. Conclusions: The benefit of placing a glass-ionomer cement liner in resin composite restoration is questionable.
Introduction Currently, resin composites are commonly used for restorations in anterior and posterior teeth. In a deep cavity, a liner/base, such as glass-ionomer cement (GIC), is usually placed on dentin at the pulpal floor in order to protect the pulp from any possible irritation.1 In addition, placing a GIC liner can reduce total polymerization shrinkage stress of the resin composite by reducing the amount of the restorative material, as well as acting like a stressabsorption layer.2 Moreover, bonding to deep dentin under simulated pulpal pressure is a challenge for resinbased adhesives, especially a total-etch adhesive. This is a result of the increase in dentin permeability and increased dentin surface wetness from dentinal fluid flow.3 In ª 2010 Blackwell Publishing Asia Pty Ltd
contrast, GIC is a water-based cement that is able to bond chemically to deep dentin with much less technique sensitivity.3 Therefore, restorations with less gap formation or microleakage are anticipated if a GIC lining is used. As previously mentioned, it seems that the application of a GIC lining might be useful for resin composite restorations, yet it has been reported that the incidence of internal gap formation under resin composite restorations with a GIC lining is likely to be greater than that of restorations without a lining.4,5 Thus, the internal seal along the cavity floor of a lined restoration might be negatively affected,4 and its longevity could deteriorate. Until recently, it has been claimed that placing a GIC lining might reduce post-operative sensitivity associated with resin composite restorations.6 It was found that in 63
Posterior composite and glass-ionomer lining
non-carious teeth, the pulpal inflammation of the teeth restored with the resin composite with a GIC lining was reported to be less than that of the unlined restored teeth.7 Nevertheless, the results from clinical trials are not clear cut; one study showed the benefit of resin-modified GIC lining in reducing post-operative sensitivity,8 while another study did not.9 For these reasons, the benefit of placing a GIC lining beneath resin composite restorations remains controversial. The purpose of this randomized, clinical trial was to investigate the effect of a GIC lining on the quality of posterior resin composite restorations, bonded with either a total-etch or self-etching adhesive, at 1 year. The null hypothesis was there is no significant difference in the restoration quality among the trial groups with and without a GIC lining, regardless of the type of adhesive used. Materials and methods The trial was conducted following the Consolidated Standards of Reporting Trials Statement10,11 and the Recommendations for Conducting Controlled Clinical Studies of Dental Restorative Materials12 from the Postgraduate Clinic of the Faculty of Dentistry, Mahidol University, Bangkok, Thailand. The project was approved by the committee of Mahidol University, Thailand. Recruitment of participants Patients aged 18–40 years, who had at least one moderate-to-deep occlusal caries lesion (2–4 mm in depth, but no exposure of the pulp) in a first or second maxillary/ mandibular molar, were recruited. Each participant was informed of the nature of the study, and consent was obtained. The sample size was calculated using Minitab 14 statistical software (Minitab, State College, PA, USA). The minimum sample size of each group was calculated, following these input conditions: power of 0.9 and P = 0.05; they increased to at least 26 restorations per group to compensate for participant dropouts during follow up. The inclusion and exclusion criteria are listed in Table 1. Participants were not enrolled if they had any medical problems or if they were unable to return for follow-up appointments. The criteria for the investigated tooth are also described in the table. In brief, the teeth used in the trial were diagnosed as having moderateto-deep primary occlusal caries without other defects, and had at least one opposing tooth. Additionally, teeth were excluded if either the cavity depth after caries removal was less than 2 mm or a pulp exposure or near pulp exposure, in which calcium hydroxide application was indicated. 64
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Table 1. Inclusion and exclusion criteria used for the recruitment of participants Inclusion criteria Dental––an investigated tooth: • Clinically diagnosed as moderate-to-deep occlusal caries; no caries detected on other surfaces • With no signs or symptoms of pulpal and periapical disease • Might exhibit pre-operative sensitivity, but was relieved immediately after stimulus removal • Had at least one antagonist tooth with occlusal contact more than 50% of the occlusal surface • Had healthy or mildly-inflamed gingival tissues, without gingival recession/alveolar bone loss Exclusion criteria Patients with one of the following medical conditions: • Psychological disorders • Neurological diseases • Temporo-mandibular disorders • Pregnancy or breast feeding • Taking any analgesic or anti-inflammatory drugs regularly • Allergy to materials used in this trial Dental––an investigated tooth: • With previous restoration(s) and/or tooth surface loss (attrition, erosion, abrasion, or abfraction) • Diagnosed as ‘‘cracked tooth syndrome’’ • That has received orthodontic treatment within the previous 3 months
In each case, patient details were recorded. To maintain privacy and confidentiality, a serial number was assigned to replace each patient’s name. Medical and dental histories were taken. The investigated tooth, supporting periodontal tissues, and existence of the opposing tooth/teeth were thoroughly examined. A pre-operative, radiographic examination using a bite-wing radiograph was routinely taken to rule out proximal caries. Restorative procedures The field of operation was isolated with the application of a rubber dam if moisture control was difficult to achieve. Otherwise, gauze/cotton rolls and the use of a saliva ejector/high-velocity evacuator were employed for moisture control. If requested, a local anaesthetic, 2% mepivacaine hydrochloride with 1:100 000 epinephrine (Scandonest 2% special, Septodent, Saint-Maur-des-Fosses Cedex, France), was administered to control tooth pain/sensitivity during the procedure. Dental caries was removed using a conservative preparation. To gain the entrance to the carious lesion, undermined enamel was removed using a round or fissure, high-speed diamond bur (Intensiv SA, Grancia, Switzerland) under an air–water coolant. ª 2010 Blackwell Publishing Asia Pty Ltd
D. Banomyong et al.
Posterior composite and glass-ionomer lining
In an attempt to guide the operator in the step of caries removal, dentine caries was stained with a caries detector dye (caries detector; Kuraray Medical, Okayama, Japan) for 10 sec and rinsed according to the manufacturer’s instruction. The stained surface was removed using slowspeed, round steel burs (Emil Lange, Engelskirchen, Germany), which were of similar size to the caries lesions, and spoon excavators (Sci-Dent, Algonquin, IL, USA) until the dentine was stained pale pink and was relatively hard. In this study, the operator attempted to remove most of the soft, carious dentine while keeping the affected and/or sclerotic dentine as much as possible. After caries removal, cavity size and depth at the greatest dimensions from cavity margins were measured (in mm) using a periodontal probe (PCP-UNC 15; Hu-Friedy, Chicago, IL, USA). One-to-four restorations were randomly allocated to a treatment-planned tooth by one operator (DB) according to a computer-generated, blocking, randomization list. Each participant was unaware of the restoration type placed; however, blinding the operator to which intervention was allocated was not possible. The prepared cavity was randomly restored using one of the following restorative procedures: (a) Single Bond 2 (SB2): bonded with a two-step, total-etch adhesive (SB2) without lining; (b) SB2/Fuji Lining LC (FLC): lined with a resin-modified GIC liner (FLC), and then bonded with total-etch adhesive; (c) Clearfil SE Bond: bonded with a two-step, selfetching adhesive (Clearfil SE Bond) without lining; and (d) SE/FLC: lined with the GIC liner, and then bonded with self-etching adhesive. Details of the restorative materials used are listed in Table 2, and all materials were applied according to the manufacturers’ instructions. In the GIC-lining groups, the lining was applied in 0.5– 1 mm thickness over the entire dentin surface. The lined and/or bonded cavity was incrementally filled ( 0.05). Discussion In this study, the survival rate of occlusal resin composite restorations at 1 year was almost 100%. Thus, occlusal caries can be successfully restored with nano-filled resin composites bonded with a two-step, total-etch or selfetching adhesive, regardless of the presence of a GIC lining, which corresponds with the results of another clinical study.13 Only one restoration was replaced because of chronic post-operative sensitivity, which is possibly due to a critical error in the bonding procedure of the totaletch adhesive.14 Furthermore, the other two restorations were later removed and included in occluso-proximal restorations because of proximal caries, and one restored tooth was extracted due to an unknown periodontal problem. Therefore, these restorations were not true failures within the selected evaluation criteria. Post-operative sensitivity is associated with posterior resin composite restorations, depending on the size and depth of the restored cavity.15,16 In fact, it is one of the negative outcomes when a dentine adhesive is not used properly and can usually be prevented by using the ª 2010 Blackwell Publishing Asia Pty Ltd
adhesive carefully in every step, following the manufacturers’ instructions.9 Usually, post-operative sensitivity can be relieved and become asymptomatic over time without any further extensive treatment.16,17 However, the sensitivity can sometimes persist and become chronic so that a replacement of the restoration is needed. It seems that the application of a GIC lining does not affect the incidence of short-term post-operative sensitivity.9 Furthermore, using a total-etch adhesive does not seem to provide a greater chance of post-operative sensitivity occurrence in comparison to a self-etching adhesive.9,17,18 It is believed that placing a GIC liner can improve the quality of the restoration by reducing polymerization shrinkage stress, and subsequently allowing superior marginal adaptation to be obtained.2,19 On the contrary, the result of this clinical trial indicated that no significant difference in marginal adaptation between the restorations with or without a resin-modified GIC lining at 1 year occurred. Unfortunately, no other clinical study investigating restorations with or without lining was found in a literature search. Similarly, the marginal adaptation of the restoration bonded with a total-etching adhesive was not superior to that bonded with a self-etching adhesive, which corresponds with results of other studies.20,21 The occlusal cavities in this study had entirely enamel margins, and the bond to the prepared enamel with the self-etching adhesive was comparable to that with the total-etch adhesive.22 This is in contrast with a laboratory study that showed better marginal adaptation in restorations bonded with a total-etch adhesive.23 In fact, the marginal defects usually need time to form and be detected, so a follow-up evaluation over a longer term is required. Controversially, the formation of recurrent caries might or might not relate to a marginal defect or leakage.24,25 However, if the marginal defect is large enough to become a site for plaque retention, recurrent caries is likely to occur.26 Theoretically, restorations with a GIC 67
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lining might have better marginal adaptation (less marginal leakage) than the restorations without a lining.19 Due to the outcome of this 1-year trial, placing a GIC lining did not improve the marginal quality of restorations in the short term. In this study, minor marginal defects were found in just a few restorations, which could be corrected by refinishing and repolishing. Clinically, any excess of restorative material might be unintentionally left at the cavity margin after finishing/polishing,27 which might eventually chip off during function and then create small marginal defects. In comparing the total-etch and self-etching adhesive, the adhesion/bond strength to uncut enamel of the former is generally better than that of the latter.28 Nevertheless, adhesion to cut enamel of a twostep, self-etching adhesive is comparable to that of a total-etching adhesive28 so that the marginal adaptation and recurrent caries of a restoration bonded with these two-step adhesives were not significantly different. The placement of a liner/base might negatively affect the overall strength of the restoration, since the lining material is weaker than the restorative material.29,30 Interestingly, it should be further investigated whether the overall strength of the restoration is reduced by the application of a liner/base of the different thicknesses (thin lining or thick base). Furthermore, internal gap formation between lining material and dentin, which is probably caused by the retraction force generated from the
References 1 Ritter AV, Edward JSJ. Current restorative concepts of pulp protection. Endodontic Topics 2003; 5: 41– 8. 2 Ferracane JL. Buonocore Lecture. Placing dental composites–a stressful experience. Oper Dent 2008; 33: 247–57. 3 Banomyong D, Palamara JEA, Burrow MF, Messer HH. Effect of dentin conditioning on dentin permeability and micro-shear bond strength. Eur J Oral Sci 2007; 115: 502–9. 4 Banomyong D, Palamara JEA, Messer HH, Burrow MF. Sealing ability of occlusal resin composite restoration using four restorative procedures. Eur J Oral Sci 2008; 116: 571–8. 5 Peliz MIL, Duarte S Jr, Dinelli W. Scanning electron microscope analysis of internal adaptation of materials
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polymerization shrinkage stress of the resin composite, has been reported to occur at the pulpal floor of the restoration.4,5 This internal gap could reduce the retention of the restoration. Nevertheless, the fracture and retention rates of the posterior resin composite restorations in this study were not negatively influenced by the placement of the GIC lining, and were independent of the adhesive used. In conclusion, the null hypotheses were accepted. No significant differences in all evaluated criteria were found among the restorations with and without a resin-modified GIC lining, regardless of the adhesive used (total-etch or self-etching adhesive) at 1 year. Moderate-to-deep occlusal cavities might be restored successfully with a nanofilled resin composite bonded with the two-step adhesives, regardless of whether a GIC liner is placed or not. In the short term, the GIC lining did not affect the quality of an occluso-posterior resin composite restoration with surrounding enamel margins. However, the GIC lining could provide the benefit of remineralizing carious-affected dentine,31 which could not be observed and are beyond the scope of this study. Moreover, the survival rate and quality of the restoration should be further observed over a longer term to confirm these short-term findings. In addition, the benefit of GIC lining in occluso-proximal restoration, with enamel or dentine gingival margin, should be also investigated.
used for pulp protection under composite resin restorations. J Esthet Restor Dent 2005; 17: 118–28. Christensen GJ. Preventing postoperative tooth sensitivity in class I, II and V restorations. J Am Dent Assoc 2002; 133: 229–31. Costa CAD, Giro EMA, do Nascimento ABL, Teixeira HM, Hebling J. Short-term evaluation of the pulpo-dentin complex response to a resin-modified glass-ionomer cement and a bonding agent applied in deep cavities. Dent Mater 2003; 19: 739–46. Akpata ES, Sadiq W. Post-operative sensitivity in glass-ionomer versus adhesive resin-lined posterior composites. Am J Dent 2001; 14: 34–8. Banomyong D, Harnirattisai C, Messer HH, Burrow MF. Effect of glass-ionomer lining on postoperative sensitivity in occlusal cavities restored with resin composite- a
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Lambrechts P. Three-year randomized clinical trial to evaluate the clinical performance and wear of a nanocomposite versus a hybrid composite. Dent Mater 2009; 25: 1302–14. Frankenberger R, Kramer N, Petschelt A. Technique sensitivity of dentin bonding: effect of application mistakes on bond strength and marginal adaptation. Oper Dent 2000; 25: 324–30. Auschill TM, Koch CA, Wolkewitz M, Hellwig E, Arweiler NB. Occurrence and causing stimuli of postoperative sensitivity in composite restorations. Oper Dent 2009; 34: 3–10. Briso ALF, Mestrener SR, Delicio G et al. Clinical assessment of postoperative sensitivity in posterior composite restorations. Oper Dent 2007; 32: 421–6. Browning WD, Blalock JS, Callan RS et al. Postoperative sensitivity: a comparison of two bonding agents. Oper Dent 2007; 32: 112–7. Casselli DSM, Martins LRM. Postoperative sensitivity in class I composite resin restorations in vivo. J Adhes Dent 2006; 8: 53–8. Chuang SF, Jin YT, Lin TS, Chang CH, Garcia-Godoy F. Effects of lining materials on microleakage and internal voids of Class II resin-
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