|Year : 2015 | Volume
| Issue : 2 | Page : 54-55
Reminder about long-term clinical trials as a gold standard for the bonding effectiveness of adhesive resins
Muhammet Kerim Ayar
Department of Restorative Dentistry, Faculty of Dentistry, Karadeniz Technical University, Trabzon, Turkey
|Date of Web Publication||8-May-2015|
Muhammet Kerim Ayar
Department of Restorative Dentistry, Faculty of Dentistry, Karadeniz Technical University, Trabzon-61080
Source of Support: None, Conflict of Interest: None
Clinical trials are considered as a gold standard for assessing bonding effectiveness of adhesive materials. However, clinical trials with long evaluation periods (5 years or more) are necessary to discriminate significant differences within the clinical performances of current improved adhesive materials. The present short communication discusses this issue and possible alternatives.
Keywords: Bonding, clinical trials, composite, dentin, durability
|How to cite this article:|
Ayar MK. Reminder about long-term clinical trials as a gold standard for the bonding effectiveness of adhesive resins. J Res Dent 2015;3:54-5
|How to cite this URL:|
Ayar MK. Reminder about long-term clinical trials as a gold standard for the bonding effectiveness of adhesive resins. J Res Dent [serial online] 2015 [cited 2020 Apr 4];3:54-5. Available from: http://www.jresdent.org/text.asp?2015/3/2/54/156648
It appears that studies using shear bond strength have invaded the research areas of dentistry. A search for the terms 'dentin', 'bond', and 'strength' in the PubMed database found 3,720 papers published before 3 January 2015. Adding the term 'shear' to the search terms found 1,453 papers; thus, demonstrating the heavy usage of shear bond strength tests to evaluate the bonding effectiveness of adhesive dentistry materials and techniques. The aim of this letter is not to criticize shear bond strength test methodology; however, these findings reveal a time deficiency of clinical trials in dentistry is that one of important difficulties of conducting long-term clinical trials. However, shear bond strength tests provide easy and somewhat and/or arguably valid in vitro data.
It seems that clinical trials with very long evaluation periods (5 years or more) are necessary to discriminate between significant differences in the clinical performances of current, improved adhesive materials; materials from 10 to 20 years ago exhibited excellent performances in long-term clinical trials.  However, a period of 5 years exceeds the length of postgraduate education in most countries. This clearly limits productivity when conducting long-term clinical trials. However, the market lives of most adhesive materials are less than 5 years. Therefore, a question of who could conduct a clinical trial with a long evaluation period to assess the clinical performance of adhesive materials, which might not be on the market when the study is published, seems meaningful. A striking example of this issue is a silorane composite material with a specific adhesive system; this material is a breakthrough novel resin composite due to its unique chemical composition. This unique composite was introduced in 2007, and its manufacturer has announced that silorane will be removed from the market by 2015. After its introduction, only one mid-term (3-year) clinical trial was conducted.  This indicates that the dental research community failed to conduct a long-term clinical study of this breakthrough composite resin because of the low market lives of the materials whatever its novelty and time deficiency of clinical trials.
These facts demonstrate that clinical trials with long-term evaluation periods, which are the gold standard for assessing the bonding effectiveness of adhesive materials, might be a myth. The dental research community should consider this information about clinical trials. Research to improve in vitro artificial aging procedures, which mimic the aging mechanism that occurs within natural mediums, should be encouraged to overcome the time deficiency of clinical trials and obtain valid data regarding the bonding effectiveness of today's improved adhesive materials.
| References|| |
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Peumans M, De Munck J, Mine A, Van Meerbeek B. Clinical effectiveness of contemporary adhesives for the restoration of non-carious cervical lesions. A systematic review. Dent Mater 2014;30:1089-103.