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Systematic review of glass-ionomer adhesives
147
Readers' forum
I2 from 18% to 46%. However, I2 values less than 50% are usually considered as exhibiting moderate heterogeneity, and a fixed-effects model could be considered.1 If that model is used, then analysis of only Pandis’s and Scott’s data would result in the same conclusion: that there was a statistically significant difference in incisor proclination (Fig 1). It is true that a random-effects model would have led us to the opposite statistical conclusion (Fig 2). However, in both situations, the mean difference in incisor proclination was about 1.6 . This difference is probably not of major clinical consequence. There will always be some room for debate when choosing studies to include or exclude in an analysis, as well as when choosing a random- or fixed-effects model. However, there is little debate that judgment must always be used when interpreting the results of a meta-analysis. In this case, readers must decide on the clinical importance of 1.6 of difference in incisor position. We would also like to emphasize the relatively few studies we identified on self-ligating appliances that were amenable to meta-analysis. Thus, we do not consider our conclusions to be robust, and they could be influenced greatly by just a couple of additional, well-conducted trials. Stephanie Chen Geoffrey Greenlee Greg Huang Seattle, Wash Am J Orthod Dentofacial Orthop 2011;139:146-7 0889-5406/$36.00 Copyright Ó 2011 by the American Association of Orthodontists. doi:10.1016/j.ajodo.2010.12.011
authors that much of the research carried out in this area (and many other areas of orthodontic research) is disappointing due to poor study design, inadequate reporting, or inappropriate statistical analyses. I hope that future researchers will take note of the authors’ recommendations, and we will start to find definitive answers to the important clinical questions soon. I would like to question one of the authors’ conclusions. They stated that “because of the limitations of successful bonding with a glass ionomer adhesive, it cannot be recommended.” Some studies they cited in the discussion as evidence for this did not actually investigate the use of glass ionomer cements. It is true that Marcusson et al1 did report a disappointing bond failure rate2; however, this was with a conventional glass ionomer cement. The newer resin-modified glass ionomers are much stronger. I have been using resin-modified glass ionomer for cementing both bands and bonds for several years and in a recent audit found that 4% of my brackets failed during use. I believe this is acceptable, particularly if it reduces the incidence and severity of unsightly demineralization during treatment, but I eagerly await the results of an RCT to confirm this. One other thing. Please can we stop upsetting the cariologists by continually referring to “decalcification”? The correct term is “demineralization,” because calcium is not the only mineral lost during the process. Philip Benson Sheffield, United Kingdom Am J Orthod Dentofacial Orthop 2011;139:147 0889-5406/$36.00 Copyright Ó 2011 by the American Association of Orthodontists. doi:10.1016/j.ajodo.2010.12.007
REFERENCE 1. Higgins JPT, Green S, editors. Cochrane handbook for systematic reviews of interventions. Version 4.2.6 (updated September 2006). The Cochrane Collaboration; 2006.
Systematic review of glass-ionomer adhesives
T
he authors of the recent systematic review of adhesives are to be congratulated on a thorough review of the literature. I know from experience how much work this involves (Rogers S, Chadwick B, Treasure E. Fluoride-containing orthodontic adhesives and decalcification in patients with fixed appliances: a systematic review. Am J Orthod Dentofacial Orthop 2010;138:390.e1-8). Systematic reviews have a bad reputation because they so often conclude that there is no satisfactory scientific evidence for our clinical practice. I agree with the
REFERENCES 1. Marcusson A, Norevall LI, Persson M. White spot reduction when using glass ionomer cement for bonding in orthodontics: a longitudinal and comparative study. Eur J Orthod 1997;19:233-42. 2. Norevall LI, Marcusson A, Persson M. A clinical evaluation of a glass ionomer cement as an orthodontic bonding adhesive compared with an acrylic resin. Eur J Orthod 1996;18:373-84.
Author’s response e agree with Dr Benson’s comments on the first conclusion of the systematic review. On reflection, the conclusion could (and should) be amended to “because of the limitations of successful bonding with conventional glass ionomer, it cannot be recommended.” The studies citied for evidence for this conclusion used Ketac Cem and Fuji Ortho LC, respectively, which we and the authors categorized as glass ionomer cements.1,2 However, to be more precise, Fuji Ortho LC can be
W
American Journal of Orthodontics and Dentofacial Orthopedics
February 2011 Vol 139 Issue 2
Readers' forum
I2 from 18% to 46%. However, I2 values less than 50% are usually considered as exhibiting moderate heterogeneity, and a fixed-effects model could be considered.1 If that model is used, then analysis of only Pandis’s and Scott’s data would result in the same conclusion: that there was a statistically significant difference in incisor proclination (Fig 1). It is true that a random-effects model would have led us to the opposite statistical conclusion (Fig 2). However, in both situations, the mean difference in incisor proclination was about 1.6 . This difference is probably not of major clinical consequence. There will always be some room for debate when choosing studies to include or exclude in an analysis, as well as when choosing a random- or fixed-effects model. However, there is little debate that judgment must always be used when interpreting the results of a meta-analysis. In this case, readers must decide on the clinical importance of 1.6 of difference in incisor position. We would also like to emphasize the relatively few studies we identified on self-ligating appliances that were amenable to meta-analysis. Thus, we do not consider our conclusions to be robust, and they could be influenced greatly by just a couple of additional, well-conducted trials. Stephanie Chen Geoffrey Greenlee Greg Huang Seattle, Wash Am J Orthod Dentofacial Orthop 2011;139:146-7 0889-5406/$36.00 Copyright Ó 2011 by the American Association of Orthodontists. doi:10.1016/j.ajodo.2010.12.011
authors that much of the research carried out in this area (and many other areas of orthodontic research) is disappointing due to poor study design, inadequate reporting, or inappropriate statistical analyses. I hope that future researchers will take note of the authors’ recommendations, and we will start to find definitive answers to the important clinical questions soon. I would like to question one of the authors’ conclusions. They stated that “because of the limitations of successful bonding with a glass ionomer adhesive, it cannot be recommended.” Some studies they cited in the discussion as evidence for this did not actually investigate the use of glass ionomer cements. It is true that Marcusson et al1 did report a disappointing bond failure rate2; however, this was with a conventional glass ionomer cement. The newer resin-modified glass ionomers are much stronger. I have been using resin-modified glass ionomer for cementing both bands and bonds for several years and in a recent audit found that 4% of my brackets failed during use. I believe this is acceptable, particularly if it reduces the incidence and severity of unsightly demineralization during treatment, but I eagerly await the results of an RCT to confirm this. One other thing. Please can we stop upsetting the cariologists by continually referring to “decalcification”? The correct term is “demineralization,” because calcium is not the only mineral lost during the process. Philip Benson Sheffield, United Kingdom Am J Orthod Dentofacial Orthop 2011;139:147 0889-5406/$36.00 Copyright Ó 2011 by the American Association of Orthodontists. doi:10.1016/j.ajodo.2010.12.007
REFERENCE 1. Higgins JPT, Green S, editors. Cochrane handbook for systematic reviews of interventions. Version 4.2.6 (updated September 2006). The Cochrane Collaboration; 2006.
Systematic review of glass-ionomer adhesives
T
he authors of the recent systematic review of adhesives are to be congratulated on a thorough review of the literature. I know from experience how much work this involves (Rogers S, Chadwick B, Treasure E. Fluoride-containing orthodontic adhesives and decalcification in patients with fixed appliances: a systematic review. Am J Orthod Dentofacial Orthop 2010;138:390.e1-8). Systematic reviews have a bad reputation because they so often conclude that there is no satisfactory scientific evidence for our clinical practice. I agree with the
REFERENCES 1. Marcusson A, Norevall LI, Persson M. White spot reduction when using glass ionomer cement for bonding in orthodontics: a longitudinal and comparative study. Eur J Orthod 1997;19:233-42. 2. Norevall LI, Marcusson A, Persson M. A clinical evaluation of a glass ionomer cement as an orthodontic bonding adhesive compared with an acrylic resin. Eur J Orthod 1996;18:373-84.
Author’s response e agree with Dr Benson’s comments on the first conclusion of the systematic review. On reflection, the conclusion could (and should) be amended to “because of the limitations of successful bonding with conventional glass ionomer, it cannot be recommended.” The studies citied for evidence for this conclusion used Ketac Cem and Fuji Ortho LC, respectively, which we and the authors categorized as glass ionomer cements.1,2 However, to be more precise, Fuji Ortho LC can be
W
American Journal of Orthodontics and Dentofacial Orthopedics
February 2011 Vol 139 Issue 2