HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Abstract Figures Only Full Text (PDF) Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Wenzel, A. Search for Related Content PubMed PubMed Citation Articles by Wenzel, A.

Bitewing and Digital Bitewing Radiography for Detection of Caries Lesions

Department of Oral Radiology, Royal Dental College, University of Aarhus, Vennelyst Blvd., DK-8000 Aarhus C, Denmark; awenzel{at}odont.au.dk

	ABSTRACT

TOP ABSTRACT BITEWING RECORDING WITH FILM... DIAGNOSTIC OUTCOMES AND... NEW DIAGNOSTIC METHODS... CONCLUSIONS REFERENCES

 
When radiography is applied in the clinic for caries detection, the recommended technique is bitewing projection (Gröndahl, 1994). This technique was introduced by Raper (1925) and has continued with only minor alterations. The aims of this report are to provide evidence for (1) optimal bitewing recording for individual examinations and clinical trials, (2) advantages and disadvantages of digital receptors for bitewing examinations, (3) the diagnostic outcomes and limitations of bitewing radiography, and (4) computer-automated detection of caries.

KEY WORDS: dental caries • digital radiography

	BITEWING RECORDING WITH FILM OR DIGITAL RECEPTORS

TOP ABSTRACT BITEWING RECORDING WITH FILM... DIAGNOSTIC OUTCOMES AND... NEW DIAGNOSTIC METHODS... CONCLUSIONS REFERENCES

 
The bitewing technique implies the use of a film-holder with a wing to bite, hence the name. It is well-known, however, that the use of a beam-aiming device as well can reduce the number of overlaps and improve image quality (for review, see Pitts, 1984a), an important issue for minimizing interpretation errors due to changes in recording geometry (for review, see Pitts, 1996). Partially overlapping surfaces, however, should not give rise to retakes, since valid diagnostic information can still be extracted (Pitts, 1986). Totally serial identical radiographs can be obtained only when the location and the orientation of the x-ray source, the patient, and the detector in space can be reproduced. If horizontal and vertical rotation errors can be prevented—for example, by careful use of a conventional aiming device such as the Kwik-bite^® holder—this may provide a homogeneity that allows for subtraction radiography (Wenzel and Andersen, 1994; Wenzel et al., 2000), a method which should be considered for the evaluation of caries behavior in longitudinal studies.

The recommendation for a posterior bitewing examination is that it should capture an image of the crowns of the teeth from the distal surface of the canine to the distal surface of the most posterior erupted molar (see textbooks, Mauriello et al., 1995; White and Pharoah, 2000). To cover this area in an adult patient with erupted third molars, the clinician must use 2 size #2 dental films or 1 long bitewing film (size #3) in each side of the mouth. The advantage of 1 long film over 2 conventional films is that the patient receives less radiation. However, significantly more overlapping surfaces, cone cuts, and missing surfaces have been found in bitewing examinations undertaken with 2 long films compared with examinations with 4 conventional films (Kaffe et al., 1984; Jensen et al., 1987). The recommendation dates from a period when caries was common in canines and first premolars. It may be argued that the four-film examination provides an additional view of most surfaces, which potentially increases the likelihood of a lesion being detected. In a recent study, however, only small differences were found between the prevalence of caries (enamel and dentin) in unrestored occlusal and approximal surfaces when the examination was performed with only 1 size #2 bitewing compared with the recommended 2 bitewings in each side of the mouth. For dentinal caries, the prevalence was 3.2% and 3.6%, respectively, and very little disease was seen in canines and first premolars (Hintze and Wenzel, 1999).

For optimal image quality to be obtained, a bitewing examination should involve an aiming device, and for exposure to be kept "as low as reasonably achievable", caries risk assessment should precede radiographic examination. In individuals—and in clinical trials in populations with low caries prevalence—one exposure in each side of the mouth, covering the most posterior teeth, may suffice.

Projection errors and retakes should be thoroughly considered when recent years’ digital radiographic receptors are brought into use in the dental clinic (Wenzel, 1999). There are two basically different concepts for digital bitewing radiography: solid-state sensors (Charge-Coupled Device [CCD] and Complementary Metal Oxide Semiconductor [CMOS] technology), where a cord connects the receptor and the computer, and storage phosphors, which appear like film and must be processed (scanned) after exposure (for reviews, see Wenzel and Gröndahl, 1995; Wenzel, 1998, 1999). The solid-state sensors are sub-optimal for bitewing examination in the clinic, since not only is the effective radiation field smaller than a size #2 film, but also the problem lies in their thickness and the cable that must come out of the subject’s mouth. General practitioners in Denmark who work with these sensors stated that they often replaced a traditional bitewing examination with from 4 to 8 periapical exposures (Wenzel and Gotfredsen, 2000). Film was still in use significantly more for bitewing examinations by Norwegian general practitioners who worked with sensors (27%) than by those who worked with storage phosphor systems (4%) (Wenzel and Møystad, 2001a,b). The phosphor plates are available in sizes similar to film. The holders available for bitewing examinations with phosphor plates appear like those for film, while the sensor holders still leave much to be desired.

A recent study using two sensor and two phosphor plate systems for bitewing examinations showed more positioning errors with the sensors (Bahrami et al., 2003). A previous study of technical errors in periapical radiography reported more retakes with a CCD sensor (28%) than with film (6%) (Versteeg et al., 1998). Thinner, cordless sensors with larger effective image areas may be available in the future, and for field studies of population groups at various sites, a sensor system connected to a portable computer might be practicable, since the image is displayed immediately after exposure and no processing has to be performed, either in wet chemicals as for film, or through scanning as for storage phosphors. Other benefits of the digital systems include reductions in radiation dose and time savings (Wenzel and Møystad, 2001b). Since the digital systems are based on re-usable receptors, the possibility for cross-contamination should be considered.

A microbiological study on contamination of the CCD sensor and the storage phosphor plate in connection with bitewing examinations demonstrated that total counts of cultivable bacteria were low (< 20), the majority being catalase-positive, Gram-positive cocci, and Gram-positive rods (Wenzel et al., 1999). It was concluded that cross-contamination poses a minor problem with both digital techniques when simple hygiene procedures are followed.

	DIAGNOSTIC OUTCOMES AND LIMITATIONS OF BITEWING RADIOGRAPHY

TOP ABSTRACT BITEWING RECORDING WITH FILM... DIAGNOSTIC OUTCOMES AND... NEW DIAGNOSTIC METHODS... CONCLUSIONS REFERENCES

 
In laboratory experiments, sensitivities for caries detection have been fairly high (50–70%) for detection of lesions reaching into the dentin (approximal and occlusal), while the fraction of false-positive recordings ranges from 3 to 30% (for review, see Wenzel, 1995). Detection rates for approximal enamel lesions are considerably lower (Hintze et al., 1994; White and Yoon, 1997). Current digital intra-oral radiography systems and recently developed dental film have been reported to be as accurate as traditional films for the detection of caries (for review, see Wenzel, 1999, 2000), although there are exceptions (Hintze and Wenzel, 2002; Hintze et al., 2002) (Fig. 1), which stresses the need for evidence when a new radiographic system is implemented. Data from laboratory experiments also seem to be reliable in the clinic (Hintze and Wenzel, 1996).

View larger version (20K): [in this window] [in a new window]   Figure 1. Differences in diagnostic accuracy (Receiver Operating Characteristics areas) for caries detection in approximal surfaces between recent digital sensor, storage phosphor, and film modalities.

However, there are limits to the radiographic examination which should be considered, particularly since lesion behavior has changed, with cavitation occurring much later than previously (Pitts and Rimmer, 1992), opening the possibility for the demineralized but non-cavitated lesion to be arrested. With only one measurement point, radiography cannot distinguish between an active and an arrested lesion. A demineralized "scar" may often be left in the hard tissues after lesion progression has been arrested, since fluoride, as a marker of remineralization, only rarely diffuses into the body of the lesion, even if it maintains an intact outer surface (Pearce et al., 1995). Moreover, radiography is not convincingly able to distinguish between cavitated and noncavitated surfaces (Nielsen et al., 1996), and the relationship between the depth of the radiographic lesion and clinical cavitation is not unequivocal. In low-prevalence populations, only a few percent of radiographic, approximal enamel lesions are cavitated. For radiographic dentinal lesions, the fraction for surfaces with cavitation has been reported to range between 50 and 90% (Ratledge et al., 2001). Radiographically deep dentinal lesions, however, are very likely to be cavitated. Lesions in occlusal surfaces, with a clinically visible breakdown of even a minor part of the surface, most often penetrate deep into dentin (Wenzel and Fejerskov, 1992), and such surfaces hardly need radiographic examination. Clinically "sound" and apparently intact occlusal surfaces, however, may develop lesions which penetrate into the dentin, sometimes named "hidden" caries (Ricketts et al., 1997). Radiography may reveal a high fraction of dentinal occlusal lesions in intact occlusal surfaces with clinical signs of caries activity (Hintze, 1993; Hintze and Wenzel, 1994). There is no evidence, however, that "automatic" radiographic screening will benefit populations with low caries experience (for review, see Pitts, 1996). In fact, such screening procedures may do more harm than good, particularly in low-prevalence populations, since the predictive value of the positive test decreases significantly with decreasing disease prevalence, leading to overdiagnosis (White and Yoon, 1997).

Since cavitation should be the ultimate endpoint before operative treatment is initiated, optimally the state of the surface should be determined before treatment planning occurs. Temporary tooth separation (Pitts and Longbottom, 1987) offers the clinician the possibility of determining whether the lesion is active or inactive, cavitated or non-cavitated, with some degree of accuracy (Hintze et al., 1998) and may be suitable in low-caries, highly motivated individuals. In a recent longitudinal study on dental students using temporary tooth separation, approximately 20% of approximal lesions with an intact surface, which were in the outer dentin radiographically, developed cavitation during the first 1-year period, indicating that not all dentinal lesions may be arrested, even among motivated individuals (Hintze et al., 1999). Temporary tooth separation is not an applicable tool in all patients or clinical trials, and monitoring lesion behavior may still rely on radiography, with its inaccuracies and observer variations taken into account.

	NEW DIAGNOSTIC METHODS FACILITATED BY DIGITAL RADIOGRAPHY

TOP ABSTRACT BITEWING RECORDING WITH FILM... DIAGNOSTIC OUTCOMES AND... NEW DIAGNOSTIC METHODS... CONCLUSIONS REFERENCES

 
When 2 radiographs are recorded with at least partly controlled projection angles, the information from the most recent one may be digitally subtracted from that from the former. Optimally, all unchanged anatomical background structures will cancel, and unchanged areas will be displayed in a neutral grey shade in the subtraction image (for review, see Wenzel, 1991). Areas with mineral loss are conventionally displayed in darker shades of grey, while areas of gain appear lighter than the background. For the detection of caries, subtraction has been used in laboratory studies (Wenzel and Halse, 1992; Halse et al., 1994), but the technique may also be applicable for monitoring caries in the clinic. A recent prospective study, evaluating lesion behavior over time (Fig. 2), found higher inter-observer agreement with assessment of subtraction images than in comparison of 2 bitewing films (Wenzel et al., 2000). A subtraction image is still a two-dimensional display of three-dimensional structures, and recent years’ developments of the tomosynthesis principle, now known as tuned-aperture computed tomography, or TACT^TM, have demonstrated that the technology’s ability to display structures in three dimensions increases the accuracy of detecting dental pathology, including caries lesions (Webber et al., 1997).

View larger version (107K): [in this window] [in a new window]   Figure 2. Subtraction image between two digital bitewing radiographs taken in general dental practice two years apart in the same individual. Due to a non-optimal standardization of the recordings, the teeth in each jaw are subtracted separately, here the upper jaw. The box illustrates a new filling, the white circle a new deep approximal caries lesion, and the black circle progression of a former enamel lesion into the dentin.

	CONCLUSIONS

TOP ABSTRACT BITEWING RECORDING WITH FILM... DIAGNOSTIC OUTCOMES AND... NEW DIAGNOSTIC METHODS... CONCLUSIONS REFERENCES

 
Bitewing radiography may still be used in individual caries diagnosis and clinical trials for detecting demineralization caused by microbial activity on the tooth surface: the caries lesion. Radiography plays a part in monitoring lesion development over time, since remineralization procedures can arrest or reverse progression of the lesion and lead to changes in mineral quality and quantity. The evidence for dental caries is not restricted to the levels of surface cavitation, and radiography can add information about many of the clinical stages of the caries process at approximal surfaces and the more advanced stages on occlusal surfaces. The most appropriate technique, low-dose receptors, and selection criteria must be considered. Subtraction radiography and the TACT technique may be promising developments in radiographic caries diagnostics and are obvious objects for further research studies.

	FOOTNOTES

 
Presented at the International Consensus Workshop on Caries Clinical Trials, Glasgow, Scotland, January 7–10, 2002

	REFERENCES

TOP ABSTRACT BITEWING RECORDING WITH FILM... DIAGNOSTIC OUTCOMES AND... NEW DIAGNOSTIC METHODS... CONCLUSIONS REFERENCES

 
Bahrami G, Hagstrøm C, Wenzel A (2003). Bitewing examination with four digital receptors. Dentomaxillofac Radiol 32:317–321.[Abstract/Free Full Text]

Firestone AR, Sema D, Heaven TJ, Weems RA (1998). The effect of a knowledge-based, image analysis and clinical decision support system on observer performance in the diagnosis of approximal caries from radiographic images. Caries Res 32:127–134.[ISI][Medline]

Gröndahl H-G (1994). The value of the radiologic examination in caries diagnosis. In: Textbook of clinical cariology. Thylstrup A, Fejerskov O, editors. Copenhagen: Munksgaard, pp. 376–382.

Halse A, Espelid I, Tveit AB, White SC (1994). Detection of mineral loss in approximal enamel by subtraction radiography. Oral Surg Oral Med Oral Pathol 77:177–182.[ISI][Medline]

Heaven TJ, Firestone AR, Feagin FF (1992). Computer-based image analysis of natural approximal caries on radiographic films. J Dent Res 71:846–849.

Hintze H (1993). Screening with conventional and digital bite-wing radiography compared to clinical examination alone for caries detection in low-risk children. Caries Res 23:499–504.

Hintze H, Wenzel A (1994). Clinically undetected dental caries assessed by bitewing screening in children with little caries experience. Dentomaxillofac Radiol 23:19–23.[Abstract]

Hintze H, Wenzel A (1996). Clinical and laboratory radiographic caries diagnosis. A study of the same teeth. Dentomaxillofac Radiol 25:115–118.[Abstract]

Hintze H, Wenzel A (1999). A two-film versus a four-film bite-wing examination for caries diagnosis in adults. Caries Res 33:380–386.[ISI][Medline]

Hintze H, Wenzel A (2002). Influence of the validation method on diagnostic accuracy for caries. A comparison of six digital and two conventional radiographic systems. Dentomaxillofac Radiol 31:44–49.[Abstract]

Hintze H, Wenzel A, Jones C (1994). In vitro comparison of D- and E-speed film radiography, RVG, and Visualix digital radiography for the detection of enamel approximal and dentinal occlusal caries lesions. Caries Res 28:363–367.[ISI][Medline]

Hintze H, Wenzel A, Danielsen B, Nyvad B (1998). Reliability of visual examination, fibre-optic transillumination, and bitewing radiography, and reproducibility of direct visual examination following tooth separation for the identification of cavitated carious lesions in contacting approximal surfaces. Caries Res 32:204–209.[ISI][Medline]

Hintze H, Wenzel A, Danielsen B (1999). Behaviour of approximal carious lesions assessed by clinical examination after tooth separation and radiography: a 2.5-year longitudinal study in young adults. Caries Res 33:415–422.[ISI][Medline]

Hintze H, Wenzel A, Frydenberg M (2002). Accuracy of caries detection with four storage phosphor systems and E-speed film. Dentomaxillofac Radiol 31:170–175.[Abstract]

Jensen ØE, Handelman SL, Iker HP (1987). Use and quality of bitewing films in private dental offices. Oral Surg Oral Med Oral Pathol 63:249–253.[ISI][Medline]

Kaffe I, Gordon M, Laufer B, Littner MM (1984). Detection of proximal carious lesions: two-film versus four-film bitewing radiography. Oral Surg 57:567–571.

Kidd EAM, Pitts NB (1990). A re-appraisal of the value of the bitewing radiograph in the diagnosis of posterior approximal caries. Br Dent J 169:195–200.[ISI][Medline]

Mauriello SM, Overman VP, Platin ER (1995). Radiographic imaging for the dental team. Philadelphia: Lippincott, pp. 131–132, 161–169.

Nielsen L-L, Hoernoe M, Wenzel A (1996). Radiographic detection of cavitation in approximal surfaces of primary teeth using a digital storage phosphor system and conventional film, and the relationship between cavitation and radiographic lesion depth: an in vitro study. Int J Paediat Dent 6:167–172.

Pearce EIF, Coote GE, Larsen MJ (1995). The distribution of fluoride in carious human enamel. J Dent Res 74:1775–1782.[Abstract/Free Full Text]

Pitts NB (1984a). Film-holding, beam-aiming and collimating devices as an aid to standardization in intra-oral radiography: a review. J Dent 12:36–46.[ISI][Medline]

Pitts NB (1984b). Detection and measurement of approximal radiolucencies by computer-aided image analysis of bitewing radiographs. Oral Surg Oral Med Oral Pathol 58:358–366.[ISI][Medline]

Pitts NB (1986). Approximal radiolucencies in partially overlapped enamel: the need for quantitation and a preliminary assessment of a computer-aided image analysis method. Quintessence Int 17:229–236.[Medline]

Pitts NB (1996). The use of bitewing radiographs in the management of dental caries: scientific and practical considerations. Dentomaxillofac Radiol 25:5–16.[Abstract]

Pitts NB, Kidd EAM (1992). Some of the factors to be considered in the prescription and timing of bitewing radiography in the diagnosis and management of dental caries. J Dent 20:74–84.[ISI][Medline]

Pitts NB, Longbottom C (1987). Temporary tooth separation with special references to the diagnosis and preventive management of equivocal approximal carious lesions. Quintessence Int 18:563–573.[Medline]

Pitts NB, Rimmer PA (1992). An in vivo comparison of radiographic and directly assessed clinical caries status of posterior approximal surfaces in primary and permanent teeth. Caries Res 26:146–152.[ISI][Medline]

Raper HR (1925). Practical clinical preventive dentistry based upon periodic Roentgen-ray examinations. J Am Dent Assoc Sept:1084–1100.

Ratledge DK, Kidd EAM, Beighton D (2001). A clinical and microbiological study of approximal carious lesions. Part 1: The relationship between cavitation, radiographic lesion depth, the site specific gingival index and the level of infection of the dentine. Caries Res 35:3–7.[ISI][Medline]

Ricketts D, Kidd E, Weerheijm K, de Soet H (1997). Hidden caries: what is it? Does it exist? Does it matter? Int Dent J 47:259–265.[Medline]

Rossmann K (1969). Image quality. Radiol Clin North Am 7:419–433.[ISI][Medline]

Verdonschot EH, Angmar-Månsson B, ten Bosch JJ, Deery CH, Huysmans MCDNJM, Pitts NB, et al. (1999). Developments in caries diagnosis and their relationship to treatment decisions and quality care. Caries Res 33:32–40.[ISI][Medline]

Versteeg CH, Sanderink GCH, van Ginkel FC, van der Stelt PF (1998). An evaluation of periapical radiography with a charge-coupled device. Dentomaxillofac Radiol 27:97–101.[Abstract]

Webber RL, Horton DA, Tyndall DA, Ludlow JB (1997). Tuned-aperture computed tomography (TACT^TM). Theory and application for three-dimensional dento-alveolar imaging. Dentomaxillofac Radiol 26:53–62.[Abstract]

Wenzel A (1991). Influence of computerized information technologies on image quality in dental radiographs. Danish Dent J 95:527–559.

Wenzel A (1995). Current trends in radiographic caries imaging. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 80:527–539.[ISI][Medline]

Wenzel A (1998). Digital radiography and caries diagnosis. Dentomaxillofac Radiol 27:3–11.[Abstract]

Wenzel A (1999). Matters to consider when implementing direct digital radiography in the dental office. Int J Comput Dent 4:269–290.

Wenzel A (2000). Digital imaging for dental caries. Dent Clinic North Am 44:319–338.

Wenzel A (2001). Computer-automated caries detection in digital bitewings: consistency of a program and its influence on observer agreement. Caries Res 35:12–20.[ISI][Medline]

Wenzel A, Andersen L (1994). A quantitative analysis of subtraction images based on bite-wing radiographs for simulated victim identification in forensic dentistry. J Forensic Odonto-Stomatol 12:1–5.[Medline]

Wenzel A, Fejerskov O (1992). Validity of diagnosis of questionable caries lesions in occlusal surfaces of extracted third molars. Caries Res 26:188–194.[ISI][Medline]

Wenzel A, Gotfredsen E (2000). An interview study with Danish dentists who work with direct digital radiography (in Danish with an English summary). Tandlaegebladet 3:130–136.

Wenzel A, Gröndahl H-G (1995). Direct digital radiography in the dental office. Int Dent J 45:27–34.[Medline]

Wenzel A, Halse A (1992). Digital subtraction radiography after stannous fluoride treatment for occlusal caries diagnosis. Oral Surg Oral Med Oral Pathol 74:824–828.[ISI][Medline]

Wenzel A, Møystad A (2001a). Decision criteria and characteristics of Norwegian general dental practitioners selecting digital radiography. Dentomaxillofac Radiol 30:197–202.[Abstract]

Wenzel A, Møystad A (2001b). Experience of Norwegian general dental practitioners with solid state and storage phosphor detectors. Dentomaxillofac Radiol 30:203–208.[Abstract]

Wenzel A, Pitts N, Verdonschot EM, Kalsbeek H (1993). Developments in radiographic caries diagnosis. J Dent 21:131–140.[ISI][Medline]

Wenzel A, Frandsen EG, Hintze H (1999). Patient discomfort and cross-infection control in bitewing examination with a storage phosphor plate and a CCD-based sensor. J Dent 27:243–246.[ISI][Medline]

Wenzel A, Anthonisen PN, Juul MB (2000). Reproducibility in the assessment of caries lesion behaviour: a comparison between conventional film and subtraction radiography. Caries Res 34:214–218.[ISI][Medline]

Wenzel A, Hintze H, Kold LM, Kold S (2002). Accuracy of computer-automated caries detection in digital radiographs compared with human observers. Eur J Oral Sci 110:1–5.

White SC, Pharoah MJ, editors (2000). Oral radiology—principles and interpretation. 4th rev. ed. St. Louis: Mosby, pp. 122–157.

White SC, Yoon DC (1997). Comparative performance of digital and conventional images for detecting proximal surface caries. Dentomaxillofac Radiol 26:32–38.[Abstract]

This article has been cited by other articles:

				E. Barberia, M. Maroto, M. Arenas, and C. C. Silva A Clinical Study of Caries Diagnosis With a Laser Fluorescence System J Am Dent Assoc, May 1, 2008; 139(5): 572 - 579. [Abstract] [Full Text] [PDF]

				A Wenzel A review of dentists' use of digital radiography and caries diagnosis with digital systems. Dentomaxillofac. Radiol., September 1, 2006; 35(5): 307 - 314. [Abstract] [Full Text] [PDF]

				N.B. Pitts and J.W. Stamm Preface J. Dent. Res., July 1, 2004; 83(suppl_1): C4 - C5. [Full Text] [PDF]

This Article Abstract Figures Only Full Text (PDF) Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Wenzel, A. Search for Related Content PubMed PubMed Citation Articles by Wenzel, A.