RESEARCH ARTICLE
Three-Year Clinical Evaluation of a Silorane Composite Resin RICARDO WALTER, DDS, MS*, LEE W. BOUSHELL, DMD, MS†, HARALD O. HEYMANN, DDS, MEd‡, ANDRE V. RITTER, DDS, MS§, JOHN R. STURDEVANT, DDS¶, ALDRIDGE D. WILDER JR, DDS**, YUNRO CHUNG, MS‡‡, EDWARD J. SWIFT JR, DMD, MS††
ABSTRACT Statement of Problem: Composite resins are still outperformed by amalgams in the clinical practice with secondary caries and fractures being their most common failures. A material that suffers less polymerization shrinkage might improve the clinical performance of composite resins. Purpose: To evaluate the clinical performance of a low-shrink silorane-based composite resin (Filtek LS Low Shrink Posterior Restorative, 3M ESPE, St. Paul, MN, USA) in comparison with a methacrylate-based composite resin (Tetric EvoCeram, Ivoclar Vivadent, Schaan, Principality of Liechtenstein) over time. Materials and Methods: Candidates in need of Class II composite resin restorations participated in this randomized controlled clinical trial. Those were 25 female and six male subjects with average age of 44.3 ± 12.7 years. Participants received 82 restorations, being 54 in premolars and 28 in molars. Procedures, which included the restoration of primary caries lesions or replacement of failing restorations, were done using modified preparations with no bevels or additional retention. Restorations were placed using Filtek LS (and dedicated self-etch adhesive) or Tetric EvoCeram (with AdheSE, Ivoclar Vivadent), following manufacturers’ instructions. Incremental placement technique was applied and the restorations were immediately finished. Follow-up evaluations occurred at six, 12, 24, and 36 months and were done using the Fédération Dentaire Internationale criteria. Statistical analysis was performed using generalized estimating equations. Results: The recall rate at 36 months was 89%. All interaction terms were not significant. Conclusions: Filtek LS performs as well as Tetric EvoCeram performs in the clinical setting at 36 months.
CLINICAL SIGNIFICANCE The silorane-based composite resin Filtek LS and the conventional methacrylate-based composite resin Tetric EvoCeram performed similarly well in posterior restorations over at least 36 months of clinical service. (J Esthet Restor Dent ••:••–••, 2013)
*Assistant professor of restorative dentistry, Department of Preventive and Restorative Sciences, University of Pennsylvania School of Dental Medicine, Philadelphia, PA, USA † Associate professor, Department of Operative Dentistry, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA ‡ Professor, Department of Operative Dentistry, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA § Professor and graduate program director, Department of Operative Dentistry, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA ¶ Associate professor, Department of Operative Dentistry, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA **Professor and assistant dean for admissions & student affairs, Department of Operative Dentistry, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA †† Professor and chair, Department of Operative Dentistry, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA ‡‡ PhD student, Department of Biostatistics, University of North Carolina Gillings School of Global Public Health, Chapel Hill, NC, USA
© 2013 Wiley Periodicals, Inc.
DOI 10.1111/jerd.12077
Journal of Esthetic and Restorative Dentistry
Vol •• • No •• • ••–•• • 2013
1
CLINICAL EVALUATION OF A SILORANE COMPOSITE RESIN Walter et al.
INTRODUCTION From the glass-filled polymethylmethacrylate resins to the current nano-sized particle bisphenol A glycidyl methacrylate-based resins, resin-based restoratives have been used for more than a half century. Improvements, which have focused mainly on polishability, wear resistance, and polymerization shrinkage stress, have considerably improved such materials and allowed them to be used in various clinical situations.1 However, composite resin restorations continue to be outperformed by amalgam in some clinical studies.2,3 The reasons for such seem to be not only material related, but also operator and patient related.4 In an attempt to provide clinicians with a tooth-colored restorative material that is less technique sensitive, a low-shrink composite resin has been developed. Idealized in the 1990s and launched in the mid 2000s, silorane composite resins aggregate the hydrophobicity of siloxanes with the low shrink and stability of oxiranes.5 That combination may potentially decrease secondary caries occurrence, which, along with bulk fractures, are the main causes of failure of composite resin restorations.4 To date, only limited data from clinical trials on the topic is available. Results from 2-year follow-up trials have shown no benefit of using the commercially available silorane composite resin (Filtek LS Low Shrink Posterior Restorative, 3M ESPE) over conventional methacrylate-based restoratives.6,7 Interestingly, shorter-term trials have shown methacrylate-based composites to outperform Filtek LS in the marginal integrity/adaptation criteria.8,9 Nevertheless, Filtek LS has shown at least satisfactory clinical performance in those trials as it did in a 2-year practice-based trial when placed in load-bearing areas.10 Meanwhile, the majority of the in vitro data comparing Filtek LS with methacrylate-based composite resins has shown that the former is more stable in regard to water sorption, mass change, and solubility;11–14 it presents better marginal integrity and adaptation15–20 and lower cuspal deflection,21–23 which are likely the result of lower polymerization shrinkage;24–26 and it has similar
2
Vol •• • No •• • ••–•• • 2013
Journal of Esthetic and Restorative Dentistry
mechanical properties.27,28 Studies showing potential limitations of Filtek LS have questioned the benefits of having a lower volumetric polymerization shrinkage since the polymerization stresses generated are similar to conventional methacrylate-based composite resins.29 Also, the elastic modulus of Filtek LS has been reported to be higher than at least some methacrylate-based composite resins, which may affect treatment outcome.29,30 Even though the in vitro data suggests that Filtek LS may outperform methacrylate-based composite resins, the limited and this far controversial clinical data do not fully support that claim. Therefore, the purpose of this study was to further investigate the clinical performance of Filtek LS in a 36-month follow-up randomized clinical trial. Based on the current in vitro literature, we hypothesize that Filtek LS will outperform the methacrylate-based composite resin Tetric EvoCeram (Ivoclar Vivadent) in the FDI World Dental Federation criteria.31
MATERIALS AND METHODS This was a randomized controlled clinical trial that evaluated two commercially available composite resins used with self-etch adhesive systems in Class II restorations in permanent teeth. The Institutional Review Board (IRB) of the University of North Carolina at Chapel Hill (UNC-CH) approved the study (protocol #05–3012), which followed the ethical principles for medical research involving human subjects in the Declaration of Helsinki32 as revised in Venice in 1983. Participants were given the right to withdraw from the study at any time. Candidates in need of at least two small- to medium-sized Class II restorations and that desire to have the teeth restored with composite resin were enrolled in the study. Recruiting was done using IRB-approved fliers placed around the UNC-CH campus. Patients in the waiting list of the Operative Dentistry Clinical Research Unit also were enrolled. To be included in the study, candidates also had to be between 18 and 70 years of age and be available for
DOI 10.1111/jerd.12077
© 2013 Wiley Periodicals, Inc.
CLINICAL EVALUATION OF A SILORANE COMPOSITE RESIN Walter et al.
recalls at 6, 12, 24, and 36 months. Subjects with history of adverse reaction to any component in the test materials, who were pregnant or lactating, who maintained poor oral hygiene, and who had advanced periodontal disease affecting teeth stability were excluded from participating in the study.
From that point on, the universal numbering system (teeth #1–32) was used to assign other teeth to be restored for the same participant (two–four restorations allowed per participant). The tooth with lower number was first assigned to the next treatment in queue and so forth. The first restoration in the following subject was performed with the next material in queue.
Thirty-one subjects with age ranging from 22 to 61 years (mean of 44.3 ± 12.7) received 82 restorations in the study. Tooth inclusion criteria included the need of restoration of caries lesion or replacement of existing failing restoration (diagnosed with bitewing radiograph and clinical examination), possibility of isolating the operatory field with rubber dam or other appropriate method, and normal response to vitality test with no periapical pathology (assessed with periapical radiograph). Teeth were excluded from the study if the lesion to be treated was in the inner third of the dentin or requiring a liner or base.
Participants signed a consent form for treatment prior to any restorative procedure. A periapical digital radiograph was taken prior to treatment when a recent film (
Three-Year Clinical Evaluation of a Silorane Composite Resin RICARDO WALTER, DDS, MS*, LEE W. BOUSHELL, DMD, MS†, HARALD O. HEYMANN, DDS, MEd‡, ANDRE V. RITTER, DDS, MS§, JOHN R. STURDEVANT, DDS¶, ALDRIDGE D. WILDER JR, DDS**, YUNRO CHUNG, MS‡‡, EDWARD J. SWIFT JR, DMD, MS††
ABSTRACT Statement of Problem: Composite resins are still outperformed by amalgams in the clinical practice with secondary caries and fractures being their most common failures. A material that suffers less polymerization shrinkage might improve the clinical performance of composite resins. Purpose: To evaluate the clinical performance of a low-shrink silorane-based composite resin (Filtek LS Low Shrink Posterior Restorative, 3M ESPE, St. Paul, MN, USA) in comparison with a methacrylate-based composite resin (Tetric EvoCeram, Ivoclar Vivadent, Schaan, Principality of Liechtenstein) over time. Materials and Methods: Candidates in need of Class II composite resin restorations participated in this randomized controlled clinical trial. Those were 25 female and six male subjects with average age of 44.3 ± 12.7 years. Participants received 82 restorations, being 54 in premolars and 28 in molars. Procedures, which included the restoration of primary caries lesions or replacement of failing restorations, were done using modified preparations with no bevels or additional retention. Restorations were placed using Filtek LS (and dedicated self-etch adhesive) or Tetric EvoCeram (with AdheSE, Ivoclar Vivadent), following manufacturers’ instructions. Incremental placement technique was applied and the restorations were immediately finished. Follow-up evaluations occurred at six, 12, 24, and 36 months and were done using the Fédération Dentaire Internationale criteria. Statistical analysis was performed using generalized estimating equations. Results: The recall rate at 36 months was 89%. All interaction terms were not significant. Conclusions: Filtek LS performs as well as Tetric EvoCeram performs in the clinical setting at 36 months.
CLINICAL SIGNIFICANCE The silorane-based composite resin Filtek LS and the conventional methacrylate-based composite resin Tetric EvoCeram performed similarly well in posterior restorations over at least 36 months of clinical service. (J Esthet Restor Dent ••:••–••, 2013)
*Assistant professor of restorative dentistry, Department of Preventive and Restorative Sciences, University of Pennsylvania School of Dental Medicine, Philadelphia, PA, USA † Associate professor, Department of Operative Dentistry, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA ‡ Professor, Department of Operative Dentistry, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA § Professor and graduate program director, Department of Operative Dentistry, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA ¶ Associate professor, Department of Operative Dentistry, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA **Professor and assistant dean for admissions & student affairs, Department of Operative Dentistry, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA †† Professor and chair, Department of Operative Dentistry, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA ‡‡ PhD student, Department of Biostatistics, University of North Carolina Gillings School of Global Public Health, Chapel Hill, NC, USA
© 2013 Wiley Periodicals, Inc.
DOI 10.1111/jerd.12077
Journal of Esthetic and Restorative Dentistry
Vol •• • No •• • ••–•• • 2013
1
CLINICAL EVALUATION OF A SILORANE COMPOSITE RESIN Walter et al.
INTRODUCTION From the glass-filled polymethylmethacrylate resins to the current nano-sized particle bisphenol A glycidyl methacrylate-based resins, resin-based restoratives have been used for more than a half century. Improvements, which have focused mainly on polishability, wear resistance, and polymerization shrinkage stress, have considerably improved such materials and allowed them to be used in various clinical situations.1 However, composite resin restorations continue to be outperformed by amalgam in some clinical studies.2,3 The reasons for such seem to be not only material related, but also operator and patient related.4 In an attempt to provide clinicians with a tooth-colored restorative material that is less technique sensitive, a low-shrink composite resin has been developed. Idealized in the 1990s and launched in the mid 2000s, silorane composite resins aggregate the hydrophobicity of siloxanes with the low shrink and stability of oxiranes.5 That combination may potentially decrease secondary caries occurrence, which, along with bulk fractures, are the main causes of failure of composite resin restorations.4 To date, only limited data from clinical trials on the topic is available. Results from 2-year follow-up trials have shown no benefit of using the commercially available silorane composite resin (Filtek LS Low Shrink Posterior Restorative, 3M ESPE) over conventional methacrylate-based restoratives.6,7 Interestingly, shorter-term trials have shown methacrylate-based composites to outperform Filtek LS in the marginal integrity/adaptation criteria.8,9 Nevertheless, Filtek LS has shown at least satisfactory clinical performance in those trials as it did in a 2-year practice-based trial when placed in load-bearing areas.10 Meanwhile, the majority of the in vitro data comparing Filtek LS with methacrylate-based composite resins has shown that the former is more stable in regard to water sorption, mass change, and solubility;11–14 it presents better marginal integrity and adaptation15–20 and lower cuspal deflection,21–23 which are likely the result of lower polymerization shrinkage;24–26 and it has similar
2
Vol •• • No •• • ••–•• • 2013
Journal of Esthetic and Restorative Dentistry
mechanical properties.27,28 Studies showing potential limitations of Filtek LS have questioned the benefits of having a lower volumetric polymerization shrinkage since the polymerization stresses generated are similar to conventional methacrylate-based composite resins.29 Also, the elastic modulus of Filtek LS has been reported to be higher than at least some methacrylate-based composite resins, which may affect treatment outcome.29,30 Even though the in vitro data suggests that Filtek LS may outperform methacrylate-based composite resins, the limited and this far controversial clinical data do not fully support that claim. Therefore, the purpose of this study was to further investigate the clinical performance of Filtek LS in a 36-month follow-up randomized clinical trial. Based on the current in vitro literature, we hypothesize that Filtek LS will outperform the methacrylate-based composite resin Tetric EvoCeram (Ivoclar Vivadent) in the FDI World Dental Federation criteria.31
MATERIALS AND METHODS This was a randomized controlled clinical trial that evaluated two commercially available composite resins used with self-etch adhesive systems in Class II restorations in permanent teeth. The Institutional Review Board (IRB) of the University of North Carolina at Chapel Hill (UNC-CH) approved the study (protocol #05–3012), which followed the ethical principles for medical research involving human subjects in the Declaration of Helsinki32 as revised in Venice in 1983. Participants were given the right to withdraw from the study at any time. Candidates in need of at least two small- to medium-sized Class II restorations and that desire to have the teeth restored with composite resin were enrolled in the study. Recruiting was done using IRB-approved fliers placed around the UNC-CH campus. Patients in the waiting list of the Operative Dentistry Clinical Research Unit also were enrolled. To be included in the study, candidates also had to be between 18 and 70 years of age and be available for
DOI 10.1111/jerd.12077
© 2013 Wiley Periodicals, Inc.
CLINICAL EVALUATION OF A SILORANE COMPOSITE RESIN Walter et al.
recalls at 6, 12, 24, and 36 months. Subjects with history of adverse reaction to any component in the test materials, who were pregnant or lactating, who maintained poor oral hygiene, and who had advanced periodontal disease affecting teeth stability were excluded from participating in the study.
From that point on, the universal numbering system (teeth #1–32) was used to assign other teeth to be restored for the same participant (two–four restorations allowed per participant). The tooth with lower number was first assigned to the next treatment in queue and so forth. The first restoration in the following subject was performed with the next material in queue.
Thirty-one subjects with age ranging from 22 to 61 years (mean of 44.3 ± 12.7) received 82 restorations in the study. Tooth inclusion criteria included the need of restoration of caries lesion or replacement of existing failing restoration (diagnosed with bitewing radiograph and clinical examination), possibility of isolating the operatory field with rubber dam or other appropriate method, and normal response to vitality test with no periapical pathology (assessed with periapical radiograph). Teeth were excluded from the study if the lesion to be treated was in the inner third of the dentin or requiring a liner or base.
Participants signed a consent form for treatment prior to any restorative procedure. A periapical digital radiograph was taken prior to treatment when a recent film (
