Chu et al Vol 11, No 2, 2013 181 REVIEW ARTICLE D ental caries can be deined as a localised acid attack of dental hard tissue as a result of the metabolism of bacterial plaque bioilm (Selwitz et al, 2007). It may also be understood as an imbal- ance towards demineralisation from remineralisa- tion (Kidd, 2005). Untreated dental caries can cause pain, form dental abscesses or even result in severe infections (Chu, 2000; Chu et al, 2002). It is a multifactorial disease, in which frequent snacking habits, poor oral hygiene and inadequate luoride exposure have been attributed to the patho- genesis of dental caries (Fejerskov et al, 1990). Early diagnosis with caries risk assessment is im- perative in contemporary caries management. Den- tists should develop appropriate protocols to help Current and Future Research in Diagnostic Criteria and Evaluation of Caries Detection Methods Chun Hung Chu a /Alex M. H. Chau b /Edward C. M. Lo c Abstract: The biochemical deinition of dental caries is reasonably understood and generally agreed upon, but there is no consensus on a clinical deinition among dentists. There are many proposed diagnostic criteria of dental caries in the dental literature. The recently developed International Caries Detection and Assessment System (ICDAS II) has been constructed to allow data comparison between studies. It can be used in epidemiological studies, public health research, clinical research, clinical practice and dental education. A good study evaluating a caries detection method should contain information on caries prevalence of the study sample and other measures, including sensitivity, speci- icity, positive predictive value (PPV) and negative predictive value (NPV). It is noteworthy that measuring sensitivity and speciicity provides no quantitative information on how likely a tested tooth is to be carious because the true caries status of the tooth is not known in a clinical situation. Moreover, the study design for caries detection should address the interpretation of predictive values because PPV and NPV are affected by the caries prevalence. The study design should also measure patient-oriented outcomes, address allocation concealment and avoid lead-time bias to generate valid and clinically relevant studies. Prudent evaluation of caries detection methods is the standard of care. This paper reviews current diagnostic criteria for caries detection and discusses proper ways to evaluate new diagnos- tic methods. Key words: assessment, caries, demineralisation, detection, diagnosis, research Oral Health Prev Dent 2013;11:181-189 Submitted for publication: 24.09.11; accepted for publication: 17.05.12 doi: 10.3290/j.ohpd.a29365 a Clinical Associate Professor, Faculty of Dentistry, University of Hong Kong. b Honorary Clinical Assistant Professor, Faculty of Dentistry, Univer- sity of Hong Kong. c Clinical Professor, Faculty of Dentistry, University of Hong Kong. Correspondence: Dr. C.H. Chu, Faculty of Dentistry, The University of Hong Kong, 34 Hospital Road, Hong Kong SAR, China. Tel: +852- 2859-0422, Fax: +852 2858 7874. Email: chchu@hkucc.hku.hk in protecting their patients from dental caries and to avoid invasive restorative treatment through ear- ly intervention. Caries detection can be facilitated in several ways. For instance, intraoral radiographs are com- monly used to aid clinical examination. Digital radi- ography allows immediate image preview and is convenient. It has special image processing tech- niques that enhance the overall display of the image. Radiographic assessment has consistently had a higher speciicity but lower sensitivity than visual inspection and other diagnostic methods. One study found that by using bitewing radiographs, 105% more caries can be detected than by clinical examination alone (Chu et al, 2008). Caries detec- tion can also be enhanced by the use of magnifying loupes. Furthermore, the sensitivity and speciicity of caries detection can be improved by the use of laser-induced luorescence (LIF) technology. For ex- ample, the DIAGNODent (KaVo Dental; Biberach/ Riss, Germany) is a small chairside battery-pow- ered, LIF-based caries detection device that uses a quantitative optical method to detect mineral loss (Chu et al, 2010). Other caries detection methods include near-infrared light (NIR) and quantitative