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Effect of irradiance from curing units on the microhardness of composite - a systematic review

Evidence-Based Dentistry (2022)Cite this article

Abstract

Purpose The systematic review aims to evaluate the effect of light irradiance from light-curing units on microhardness of composite.

Materials and methods The protocol was registered in PROSPERO following which primary search was carried out via MedLine, Scopus and Cochrane Library. A customised tool was used to assess the risk of bias. Among the 303 records retrieved from the databases, only ten articles qualified for qualitative synthesis after meeting all the requirements of the eligibility criteria. Covidence software was used to record the decisions. The studies published until 31 March 2021 were taken up for the review. The articles showed a low-to-moderate risk of bias.

Results From a total of 303 articles, ten articles were reviewed for full text. Ten in vitro studies were included for qualitative analysis. There was heterogeneity in sample size, curing time and outcome measured. Therefore, meta-analysis was not performed. Out of ten studies, seven studies reported higher microhardness value for higher intensity than lower intensity of light.

Conclusion Despite the fact that the findings of the evaluated studies are quite variable, significant scientific evidence revealed that high light intensity can enhance the hardness of resin composites.

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References

  1. Leinfelder K F. A conservative approach to placing posterior composite resin restorations. J Am Dent Assoc 1996; 127: 743-748.

  2. Bassiouny M A, Grant A A. A visible light-cured composite restorative. Clinical open assessment. Br Dent J 1978; 145: 327-330.

  3. Stansbury J W. Curing dental resins and composites by photopolymerization. J Esthet Dent 2000; 12: 300-308.

  4. Rueggeberg F A, Giannini M, Arrais C A G, Price R B T. Light curing in dentistry and clinical implications: a literature review. Braz Oral Res 2017; DOI: 10.1590/1807-3107BOR-2017.vol31.0061.

  5. Gan J K, Yap A U, Cheong J W, Arista N, Tan C. Bulk-Fill Composites: Effectiveness of Cure With Poly-and Monowave Curing Lights and Modes. Oper Dent 2018; 43: 136-143.

  6. Santini A, Miletic V, Swift M D, Bradley M. Degree of conversion and microhardness of TPO-containing resin-based composites cured by polywave and monowave LED units. J Dent 2012; 40: 577-584.

  7. Leprince J, Devaux J, Mullier T, Vreven J, Leloup G. Pulpal-temperature rise and polymerization efficiency of LED curing lights. Oper Dent 2010; 35: 220-230.

  8. Jandt K D, Mills R W. A brief history of LED photopolymerization. Dent Mater 2013; 29: 605-617.

  9. Price R B T, Fahey J, Felix C M. Knoop microhardness mapping used to compare the efficacy of LED, QTH and PAC curing lights. Oper Dent 2010; 35: 58-68.

  10. Schneider L F J, Cavalcante L M, Prahl S A, Pfeifer C S, Ferracane J L. Curing efficiency of dental resin composites formulated with camphorquinone or trimethylbenzoyl-diphenyl-phosphine oxide. Dent Mater 2012; 28: 392-397.

  11. Price R B T, Felix C A. Effect of delivering light in specific narrow bandwidths from 394 to 515nm on the micro-hardness of resin composites. Dent Mater 2009; 25: 899-908.

  12. Rueggeberg F A. State-of-the-art: dental photocuring-a review. Dent Mater 2011; 27: 39-52.

  13. Yap A U. Effectiveness of polymerization in composite restoratives claiming bulk placement: impact of cavity depth and exposure time. Oper Dent 2000; 25: 113-120.

  14. Price R B, Dérand T, Loney R W, Andreou P. Effect of light source and specimen thickness on the surface hardness of resin composite. Am J Dent 2002; 15: 47-53.

  15. Sobrinho L C, Goes M F, Consani S, Sinhoreti M A, Knowles J C. Correlation between light intensity and exposure time on the hardness of composite resin. J Mater Sci Mater Med 2000; 11: 361-364.

  16. Calheiros F C, Kawano Y, Stansbury J W, Braga R R. Influence of radiant exposure on contraction stress, degree of conversion and mechanical properties of resin composites. Dent Mater 2006; 22: 799-803.

  17. Rueggeberg F A, Caughman W F, Curtis J W. Effect of light intensity and exposure duration on cure of resin composite. Oper Dent 1994; 19: 26-32.

  18. Kirkpatrick S. A primer on radiometry. Dent Mater 2005; 21: 21-26.

  19. Nomoto R. Effect of light wavelength on polymerization of light-cured resins. Dent Mater J 1997; 16: 60-73.

  20. Khalichi P, Singh J, Cvitkovitch D G, Santerre J P. The influence of triethylene glycol derived from dental composite resins on the regulation of Streptococcus mutans gene expression. Biomaterials 2009; 30: 452-459.

  21. Demarco F F, Collares K, Correa M B, Cenci M S, de Moraes R R, Opdam N J. Should my composite restorations last forever? Why are they failing? Braz Oral Res 2017; DOI: 10.1590/1807-3107BOR-2017.vol31.0056.

  22. Caughman W F, Caughman G B, Shiflett R A, Rueggeberg F, Schuster G S. Correlation of cytotoxicity, filler loading and curing time of dental composites. Biomaterials 1991; 12: 737-740.

  23. Oberholzer T G, Schünemann M, Kidd M. Effect of LED curing on microleakage and microhardness of Class V resin-based composite restorations. Int Dent J 2004; 54: 15-20.

  24. Stansbury J W, Trujillo-Lemon M, Lu H, Ding X, Lin Y, Ge J. Conversion-dependent shrinkage stress and strain in dental resins and composites. Dent Mater 2005; 21: 56-67.

  25. Filho J D N, Poskus L T, Guimarães J G A, Barcellos A A L, Silva E M. Degree of conversion and plasticization of dimethacrylate-based polymeric matrices: influence of light-curing mode. J Oral Sci 2008; 50: 315-321.

  26. Pires J A, Cvitko E, Denehy G E, Swift E J. Effects of curing tip distance on light intensity and composite resin microhardness. Quintessence Int Berl Ger 1993; 24: 517-521.

  27. Groninger A I S, Soares G P, Sasaki R T, Ambrosano G M B, Lovadino J R, Aguiar F H B. Microhardness of nanofilled composite resin light-cured by LED or QTH units with different times. Braz J Oral Sci 2011; 10: 189-192.

  28. Vandewalle K S, Roberts H W, Rueggeberg F A. Power distribution across the face of different light guides and its effect on composite surface microhardness. J Esthet Restor Dent 2008; 20: 108-117; discussion 118.

  29. Hansen E K, Asmussen E. Correlation between depth of cure and surface hardness of a light-activated resin. Scand J Dent Res 1993; 101: 62-64.

  30. Baharav H, Abraham D, Cardash H S, Helft M. Effect of exposure time on the depth of polymerization of a visible light-cured composite resin. J Oral Rehabil 1988; 15: 167-172.

  31. AlShwaimi E, Bogari D, Ajaj R, Al-Shahrani S, Almas K, Majeed A. In Vitro Antimicrobial Effectiveness of Root Canal Sealers against Enterococcus faecalis: A Systematic Review. J Endod 2016; 42: 1588-1597.

  32. Alkhudhairy F I. The effect of curing intensity on mechanical properties of different bulk-fill composite resins. Clin Cosmet Investig Dent 2017; DOI: 10.2147/CCIDE.S130085.

  33. Leprince J, Devaux J, Mullier T, Vreven J, Leloup G. Pulpal-temperature rise and polymerization efficiency of LED curing lights. Oper Dent 2010; 35: 220-230.

  34. Conte G, Panetta M, Mancini M et al. Curing effectiveness of single-peak and multi-peak led light curing units on tpo-containing resin composites with different chromatic characteristics. Oral Implantol (Rome) 2017; DOI: 10.11138/orl/2017.10.2.140.

  35. Park S-H, Kim S-S, Cho Y-S, Lee S-Y, Noh B-D. Comparison of linear polymerization shrinkage and microhardness between QTH-cured & LED-cured composites. Oper Dent 2005; 30: 461-467.

  36. Haenel T, Hausnerová B, Steinhaus J, Price R B T, Sullivan B, Moeginger B. Effect of the irradiance distribution from light curing units on the local micro-hardness of the surface of dental resins. Dent Mater 2015; 31: 93-104.

  37. Soto-Montero J, Nima G, Rueggeberg F A, Dias C, Giannini M. Influence of Multiple Peak Light-emitting-diode Curing Unit Beam Homogenization Tips on Microhardness of Resin Composites. Oper Dent 2020; 45: 327-338.

  38. Cardia G S, Ishikiriama S K, Borges A F S, Bombonatti J F S, Furuse A Y, Francisconi P A S. Curing depth of a silorane-based resin composite. Revista Sul-Brasileira de Odontologia 2015; 12: 196-201.

  39. Gritsch K, Souvannasot S, Schembri C, Farge P, Grosgogeat B. Influence of light energy and power density on the microhardness of two nanohybrid composites. Eur J Oral Sci 2008; 116: 77-82.

  40. Cavalcante L M A, Valentino T A, Carlini B, Silikas N, Pimenta L A F. Influence of different exposure time required to stabilize hardness values of composite resin restorations. J Contemp Dent Pract 2009; 10: 42-50.

  41. Bucuta S, Ilie N. Light transmittance and micro-mechanical properties of bulk fill vs. conventional resin based composites. Clin Oral Investig 2014; 18: 1991-2000.

  42. Fan P L, Schumacher R M, Azzolin K, Geary R, Eichmiller F C. Curing-light intensity and depth of cure of resin-based composites tested according to international standards. J Am Dent Assoc 2002; 133: 429-434; quiz 491-493.

  43. Al Shaafi M, Maawadh A, Al Qahtani M. Evaluation of light intensity output of QTH and LED curing devices in various governmental health institutions. Oper Dent 2011; 36: 356-361.

  44. Rb P, Ca F. Effect of delivering light in specific narrow bandwidths from 394 to 515nm on the micro-hardness of resin composites. Dent Mater 2009; 25: 899-908.

  45. Swift E J, Pawlus M A, Vargas M A, Fortin D. Depth of cure of resin-modified glass ionomers. Dent Mater 1995; 11: 196-200.

  46. Miletic V, Santini A. Micro-Raman spectroscopic analysis of the degree of conversion of composite resins containing different initiators cured by polywave or monowave LED units. J Dent 2012; 40: 106-113.

  47. Park H-J, Son S-A, Hur B, Kim H-C, Kwon Y-H, Park J-K. Effect of the difference in spectral outputs of the single and dual-peak LEDs on the microhardness and the colour stability of resin composites. J Korean Acad Conserv Dent 2011; 36: 108-113.

  48. Watts D C, Amer O, Combe E C. Characteristics of visible-light-activated composite systems. Br Dent J 1984; 156: 209-215.

  49. Cramer N B, Stansbury J W, Bowman C N. Recent advances and developments in composite dental restorative materials. J Dent Res 2011; 90: 402-416.

  50. Ganster B, Fischer U K, Moszner N, Liska R. New Photocleavable Structures. Diacylgermane-Based Photoinitiators for Visible Light Curing. Macromolecules 2008; 41: 2394-2400.

  51. Ganster B, Fischer U K, Moszner N, Liska R. New Photocleavable Structures, 4: Acylgermane-Based Photoinitiator for Visible Light Curing. Macromol Rapid Commun 2008; 29: 57-62.

  52. Moszner N, Fischer U K, Ganster B, Liska R, Rheinberger V. Benzoyl germanium derivatives as novel visible light photoinitiators for dental materials. Dent Mater 2008; 24: 901-907.

  53. Moszner N, Zeuner F, Lamparth I, Fischer U K. Benzoylgermanium Derivatives as Novel Visible-Light Photoinitiators for Dental Composites: Benzoylgermanium Derivatives as Novel Visible-Light Photoinitiators. Macromol Mater Eng 2009; 294: 877-886.

  54. Cramer N B, Stansbury J W, Bowman C N. Recent Advances and Developments in Composite Dental Restorative Materials. J Dent Res 2011; 90: 402-416.

  55. Menees T S, Lin C P, Kojic D D, Burgess J O, Lawson N C. Depth of cure of bulk fill composites with monowave and polywave curing lights. Am J Dent 2015; 28: 357-361.

  56. Ilie N, Bucuta S, Draenert M. Bulk-fill resin-based composites: an in vitro assessment of their mechanical performance. Oper Dent 2013; 38: 618-625.

  57. Price R B T, Felix C A, Andreou P. Third-generation vs a second-generation LED curing light: effect on Knoop microhardness. Compend Contin Educ Dent 2006; 27: 490-496; quiz 497, 518.

  58. Ilie N, Hickel R. Can CQ be completely replaced by alternative initiators in dental adhesives? Dent Mater J 2008; 27: 221-228.

  59. Schneider L F J, Pfeifer C S C, Consani S, Prahl S A, Ferracane J L. Influence of photoinitiator type on the rate of polymerization, degree of conversion, hardness and yellowing of dental resin composites. Dent Mater 2008; 24: 1169-1177.

  60. Schneider L F J, Consani S, Sakaguchi R L, Ferracane J L. Alternative photoinitiator system reduces the rate of stress development without compromising the final properties of the dental composite. Dent Mater 2009; 25: 566-572.

  61. Arikawa H, Takahashi H, Kanie T, Ban S. Effect of various visible light photoinitiators on the polymerization and colour of light-activated resins. Dent Mater J 2009; 28: 454-460.

  62. Price R B T, Felix C A, Andreou P. Evaluation of a dual peak third generation LED curing light. Compend Contin Educ Dent 2005; 26: 331-332, 334, 336-338 passim; quiz 348.

  63. Yearn J A. Factors affecting cure of visible light activated composites. Int Dent J 1985; 35: 218-225.

  64. Della Bona A, Benetti P, Borba M, Cecchetti D. Flexural and diametral tensile strength of composite resins. Braz Oral Res 2008; 22: 84-89.

  65. Watts D C. Reaction kinetics and mechanics in photo-polymerised networks. Dent Mater 2005; 21: 27-35.

  66. Emami N, Soderholm K-J M. How light irradiance and curing time affect monomer conversion in light-cured resin composites. Eur J Oral Sci 2003; 111: 536-542.

  67. Lovell L G, Lu H, Elliott J E, Stansbury J W, Bowman C N. The effect of cure rate on the mechanical properties of dental resins. Dent Mater 2001; 17: 504-511.

  68. Torno V, Soares P, Martin J M H, Mazur R F, Souza E M, Vieira S. Effects of irradiance, wavelength, and thermal emission of different light curing units on the Knoop and Vickers hardness of a composite resin. J Biomed Mater Res B Appl Biomater 2008; DOI: 10.1002/jbm.b.30929.

  69. Zach L, Cohen G. Pulp response to externally applied heat. Oral Surg Oral Med Oral Pathol 1965; 19: 515-530.

  70. Baldissara P, Catapano S, Scotti R. Clinical and histological evaluation of thermal injury thresholds in human teeth: a preliminary study. J Oral Rehabil 1997; 24: 791-801.

  71. Vandewalle K S, Roberts H W, Tiba A, Charlton D G. Thermal emission and curing efficiency of LED and halogen curing lights. Oper Dent 2005; 30: 257-264.

  72. Asmussen E, Peutzfeldt A. Temperature rise induced by some light emitting diode and quartz-tungsten-halogen curing units. Eur J Oral Sci 2005; 113: 96-98.

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Authors and Affiliations

  1. Department of Conservative Dentistry and Endodontics, Amrita School of Dentistry, Amrita Vishwa Vidyapeetham, Kochi 682041, India

    Neenu Francis, Rakesh R. Rajan, Anju Varughese & C. M. Sapna

  2. Department of Public Health Dentistry, Amrita School of Dentistry, Amrita Vishwa Vidyapeetham, Kochi 682041, India

    Vijay Kumar & Vineetha Karuveetil

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  1. Neenu Francis
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Dr Neenu Francis, Dr Rakesh R. Rajan, Dr S.Vijay Kumar: conceptualisation and article screening. Dr Neenu Francis, Dr Vineetha Karuveetil: methodology and statistical analysis. Dr Neenu Francis, Dr Rakesh R. Rajan, Dr Anju Varughese, Dr C. M. Sapna: writing - original draft, writing - review and editing.

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Francis, N., Rajan, R., Kumar, V. et al. Effect of irradiance from curing units on the microhardness of composite - a systematic review. Evid Based Dent (2022). https://doi.org/10.1038/s41432-022-0824-z

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