Editorial Radiographic screening for identification of children in need of orthodontic treatment? Screening is defined as the examination of a total population for the early diagnosis and secondary prevention of a given disease and is carried out whether or not symptoms exist. Dentists traditionally conduct clinical screening examinations at standard, often arbitrarily chosen, time intervals. They also, to some extent, conduct radiographic screening despite both international and national recommendations1-3 that there must be sound clinical or histological indication for such examinations. Thus, in many countries radiographic screening is performed as part of the diagnostic routine; for example, routine bitewing radiography is carried out for the detection of dental caries and radiography of the teeth and jaw bones as part of clinical orthodontic screening to detect dentoalveolar anomalies and to monitor dental development. Even though the risks incurred in the use of ionizing radiation for such purposes may be considered negligible, it should be the minimum ethical requirement that a risklbenefit evaluatiorrP has documented that patients profit from the procedure. While the need for solid evaluation of treatment effects, using randomized controls and blind measurement techniques, is agreed by most researchers, new diagnostic methods are often adopted without a proper assessment of their value. The value of a diagnostic test should be assessed in terms of accuracy (sensitivity, specificity, and predictive values of the test outcome) and/or reproducibility. It should be mandatory that any diagnostic routine - on a par with treatment strategies is based on research rather than empiricism or availability. Radiographic screening for developmental anomalies, mostly missing teeth", entered clinical practice in the early 1970s, due to availability of a new technique, panoramic radiography, which greatly facilitated radiographic examinations in comparison with a full mouth intra-oral survey, rather than an evaluation of its benefits to the child population. Panoramic screening was justified on the basis of studies recording the number and nature of dentoalveolar developmental anomalies/'' I. Remarkably little attention was, however, paid to the diagnostic information it yielded in relation to the treatment consequences. More recently, the value of radiographic screening has been questioned5.12.13 . Comparative clinical and radiographic studies have demonstrated that the majority of the radiographic findings from screening duplicate those that are clinically detectable or suspected. Less than 2% of a study population had findings from screening which led to changes in the treatment plan which would otherwise have been established on the
basis of a clinical examination with selective radiographyo P . Compared with the latter, the diagnostic yield from radiographic screening does not appear to be effective. In the same way, panoramic screening of the whole child population may not be the appropriate diagnostic means for identifying the ~proximately 9% with developmentally missing teeth 4.15. It could be argued that a thorough clinical examination with specific radiographs for those suspected of anomalies would be sufficient for identifying the majority of these children. In many countries, screening is conducted at an early age on the grounds that early diagnosis will improve prognosis and shorten the treatment period. Studies based on the principles mentioned above for evaluation of diagnostic tests have revealed that a clinical examination with selective radiography is not very effective for identifying missing premolars (sensitivity 0.22) in 9-10 year olds, whereas it can efficiently detect those with missing permanent incisors (sensitivity 1.00)14.15. However, in most orthodontic practices, treatment for premolar aplasia is not initiated this young, so that early diagnosis is of no significance for either the timing of treatment or prognosis. This will be true in those countries where the treatment for developmentally missing teeth is to leave the deciduous molar as long as possible or to offer traditional fixed appliances at the period of maximal growth. The only case where detection is relevant at this early stage is when transplantation of another premolar is the treatment of choice. As such, a panoramic examination, if not omitted, could at least be postponed until children reach their growth spurt with very few ill-consequences'P-!". Screening can then be replaced by selective radiography of those who do not show signs of premolar eruption. For this reason, clinical orthodontic screening has now been postponed in several countries until the children reach 11-12 years old. At this age clinical examination with selective radiography is able to successfully identify the vast majority of those in need of orthodontic treatment (in this study it failed to detect only 2%) and to exclude the healthy children!". A thorough evaluation of any diagnostic method is now absolutely essential before its routine use in clinical practice. Although the risk of radiation-induced cancers from dental radiogra~hic screening examinations may be inconsiderable 7, the justification for examining a total child population in this fashion for dentoalveolar anomalies should be reconsidered. Further, it has been estimated that 6.4 million DKK is spent annually merely on oral radiographic screening Dentomaxillofac. Radiol., 1991, Vol. 20, August
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Editorial examinations in Denmark 17. In relation to the diagnostic gain, this must be an unacceptably high cost/benefit ratio.
References I. International Commission on Radiological Protection. Protection Against Ionizing Radiation from External Sources used in Medicine. (ICRP Publication 33). Oxford: Pergamon, 1982. 2. International Commission on Radiological Protection. Protection of the Patient in Diagnostic Radiography (ICRP Publication 34). Oxford: Pergamon, 1983; 5: 13. 3. Council of Dental Materials, Instruments and Equipment. Recommendations in radiographic practices. J Am Dent Assoc 1989; 118: 115-7. 4. Danforth RA, Gibbs SJ. Diagnostic dental radiation: what is the risk? CDA 1980; 8: 28-35. 5. Kogon SL, Stephens RG. Selective radiography instead of screening pantomography - a risklbenefit evaluation. Can Dent Assoc J 1982; 48: 271-5. 6. Hintze H, Wenzel A, Williams S. Panoramic screening for dental anomalies assessed by professionals with identical and different backgrounds. Scand J Dent Res 1989; 97: 60-5. 7. Haavikko K. Hypodontia of permanent teeth. An orthopantomographic study. Proc Finn Dent Soc 1971; 67: 219-25. 8. Bergstrom K. An orthopantomographic study of hypodontia, supernumeraries and other anomalies in school children between the ages of 8-9 years. An epidemiological study. Swed Dent J 1977; I: 145-57.
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9. Locht S. Panoramic radiographic examination of 704 Danish children aged 9-10 years. Community Dent Oral Epidemiol1980; 8: 375-80. 10. Lervik T, Cowley Gc. Observations of dental disease and anomalies in 9- to II-year-old Norwegian children. Acta Odontol Scand 1983; 41: 45-51. II. Buenviaja TM, Rapp R. Dental anomalies in children: a clinical and radiographic survey. J Dent Child 1984; 51: 42--6. 12. Barrett AP, Waters BE, Griffiths CJ. A critical evaluation of panoramic radiography as a screening procedure in dental practice. Oral Surg Oral Med Oral Patho11984; 57: 673-7. 13. Brooks SL. A study of selection criteria for intraoral dental radiography. Oral Surg Oral Med Oral Path01 1986; 62: 234-9. 14. Hintze H, Wenzel A. Accuracy of clinical diagnosis for the detection of dentoalveolar anomalies with panoramic radiography as validating criterion. J Dent Child 1990; 57: 119-23. 15. Hintze H, Wenzel A. Longitudinal study of accuracy of clinical examination for the detection of permanent tooth aplasia. Community Dent Oral Epidemiol1990; 18: 256-9. 16. Hintze H, Wenzel A, Williams S. Diagnostic value of clinical examination for the identification of children in need of orthodontic treatment compared to clinical examination and screening pantomography. Eur J Orthod 1990; 12: 285-8. 17. Hintze H, Wenzel A. Oral radiographic screening in Danish children. Scand J Dent Res 1990; 98: 47-52.
Ann Wenzel Department of Oral Medicine and Diagnosis, Royal Dental College Aarhus, Denmark
basis of a clinical examination with selective radiographyo P . Compared with the latter, the diagnostic yield from radiographic screening does not appear to be effective. In the same way, panoramic screening of the whole child population may not be the appropriate diagnostic means for identifying the ~proximately 9% with developmentally missing teeth 4.15. It could be argued that a thorough clinical examination with specific radiographs for those suspected of anomalies would be sufficient for identifying the majority of these children. In many countries, screening is conducted at an early age on the grounds that early diagnosis will improve prognosis and shorten the treatment period. Studies based on the principles mentioned above for evaluation of diagnostic tests have revealed that a clinical examination with selective radiography is not very effective for identifying missing premolars (sensitivity 0.22) in 9-10 year olds, whereas it can efficiently detect those with missing permanent incisors (sensitivity 1.00)14.15. However, in most orthodontic practices, treatment for premolar aplasia is not initiated this young, so that early diagnosis is of no significance for either the timing of treatment or prognosis. This will be true in those countries where the treatment for developmentally missing teeth is to leave the deciduous molar as long as possible or to offer traditional fixed appliances at the period of maximal growth. The only case where detection is relevant at this early stage is when transplantation of another premolar is the treatment of choice. As such, a panoramic examination, if not omitted, could at least be postponed until children reach their growth spurt with very few ill-consequences'P-!". Screening can then be replaced by selective radiography of those who do not show signs of premolar eruption. For this reason, clinical orthodontic screening has now been postponed in several countries until the children reach 11-12 years old. At this age clinical examination with selective radiography is able to successfully identify the vast majority of those in need of orthodontic treatment (in this study it failed to detect only 2%) and to exclude the healthy children!". A thorough evaluation of any diagnostic method is now absolutely essential before its routine use in clinical practice. Although the risk of radiation-induced cancers from dental radiogra~hic screening examinations may be inconsiderable 7, the justification for examining a total child population in this fashion for dentoalveolar anomalies should be reconsidered. Further, it has been estimated that 6.4 million DKK is spent annually merely on oral radiographic screening Dentomaxillofac. Radiol., 1991, Vol. 20, August
115
Editorial examinations in Denmark 17. In relation to the diagnostic gain, this must be an unacceptably high cost/benefit ratio.
References I. International Commission on Radiological Protection. Protection Against Ionizing Radiation from External Sources used in Medicine. (ICRP Publication 33). Oxford: Pergamon, 1982. 2. International Commission on Radiological Protection. Protection of the Patient in Diagnostic Radiography (ICRP Publication 34). Oxford: Pergamon, 1983; 5: 13. 3. Council of Dental Materials, Instruments and Equipment. Recommendations in radiographic practices. J Am Dent Assoc 1989; 118: 115-7. 4. Danforth RA, Gibbs SJ. Diagnostic dental radiation: what is the risk? CDA 1980; 8: 28-35. 5. Kogon SL, Stephens RG. Selective radiography instead of screening pantomography - a risklbenefit evaluation. Can Dent Assoc J 1982; 48: 271-5. 6. Hintze H, Wenzel A, Williams S. Panoramic screening for dental anomalies assessed by professionals with identical and different backgrounds. Scand J Dent Res 1989; 97: 60-5. 7. Haavikko K. Hypodontia of permanent teeth. An orthopantomographic study. Proc Finn Dent Soc 1971; 67: 219-25. 8. Bergstrom K. An orthopantomographic study of hypodontia, supernumeraries and other anomalies in school children between the ages of 8-9 years. An epidemiological study. Swed Dent J 1977; I: 145-57.
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9. Locht S. Panoramic radiographic examination of 704 Danish children aged 9-10 years. Community Dent Oral Epidemiol1980; 8: 375-80. 10. Lervik T, Cowley Gc. Observations of dental disease and anomalies in 9- to II-year-old Norwegian children. Acta Odontol Scand 1983; 41: 45-51. II. Buenviaja TM, Rapp R. Dental anomalies in children: a clinical and radiographic survey. J Dent Child 1984; 51: 42--6. 12. Barrett AP, Waters BE, Griffiths CJ. A critical evaluation of panoramic radiography as a screening procedure in dental practice. Oral Surg Oral Med Oral Patho11984; 57: 673-7. 13. Brooks SL. A study of selection criteria for intraoral dental radiography. Oral Surg Oral Med Oral Path01 1986; 62: 234-9. 14. Hintze H, Wenzel A. Accuracy of clinical diagnosis for the detection of dentoalveolar anomalies with panoramic radiography as validating criterion. J Dent Child 1990; 57: 119-23. 15. Hintze H, Wenzel A. Longitudinal study of accuracy of clinical examination for the detection of permanent tooth aplasia. Community Dent Oral Epidemiol1990; 18: 256-9. 16. Hintze H, Wenzel A, Williams S. Diagnostic value of clinical examination for the identification of children in need of orthodontic treatment compared to clinical examination and screening pantomography. Eur J Orthod 1990; 12: 285-8. 17. Hintze H, Wenzel A. Oral radiographic screening in Danish children. Scand J Dent Res 1990; 98: 47-52.
Ann Wenzel Department of Oral Medicine and Diagnosis, Royal Dental College Aarhus, Denmark
