Brunton Decision-Making in Operative Dentistry

1. Auflage 2002
ISBN: 978-1-85097-303-4
Verlag: Quintessence Publishing Co. Ltd.
Format: EPUB
Kopierschutz: Adobe DRM (»Systemvoraussetzungen)

E-Book, Englisch, Band 3, 112 Seiten

Reihe: QuintEssentials of Dental Practice

Operative Dentistry is a rapidly changing field of restorative dentistry. Advances in caries diagnosis and management strategies, pulp protection philosophies, tooth preparation techniques and dental materials have left practitioners somewhat unsure as to what is best practice.

This book answers many of the questions frequently posed by practitioners, encourages a less interventive philosophy and is an easy-to-use resource for clinical decision-making.

Autoren/Hrsg.

Brunton, Paul A.

Leseproben

Chapter 1
Clinical Diagnosis of Dental Caries. Is it Caries?
Aim
With changing patterns of disease experience the diagnosis of caries, particularly in its early stages, continues to be difficult for clinicians. The aim of this chapter is to improve understanding of modern methods of caries diagnosis. Outcome
Practitioners will be familiar with modern methods of detecting dental caries and their relevance to contemporary dental practice. Introduction
The pattern of dental caries has changed in recent years, with smooth surface lesions becoming less common and new lesions more likely to develop in pits and fissures. It is arguably easier to diagnose early caries on smooth surfaces (with the exception of proximal surfaces) than in pits and fissures, particularly when occult occlusal caries is present. In this condition the tooth can appear sound when examined visually but on radiographic examination there is extensive caries affecting the dentine (Fig 1-1). Fig 1-1 Radiograph showing caries as follows: mesial 16, distal and mesial 15, distal 45, mesial and distal 46 and mesial 47. Diagnostic Tests
With all diagnostic tests there is potential for operator error. For example, four outcomes are possible when a diagnostic test is applied to detect caries. These are as follows: True positive
This occurs when caries is present and the test correctly identifies this. A good diagnostic test will have a high percentage of true positive outcomes. False positive
A false positive result occurs when a diagnostic test incorrectly identifies caries when caries is not present. True negative
This outcome is the opposite of a true positive result. It occurs when the test correctly identifies an individual as caries free and they are, in fact, free of the condition. False negative
If a patient has caries and the test incorrectly deems them to be caries free then the outcome is defined as false negative. These four possible outcomes of a diagnostic test are summarised in Fig 1-2. Fig 1-2 Diagrammatic representation of diagnostic test outcomes. Sensitivity and Specificity
Sensitivity and specificity are both measures of how accurate a diagnostic test is in terms of its ability correctly to identify individuals as diseased and non-diseased. Sensitivity is defined as the proportion of true positives that are correctly identified. It is calculated as follows (true negative = a, false negative = b, false positive = c, true positive = d): The numbers of true positives and false negatives are related numerically; hence the proportion of true positive results for a diagnostic test (sensitivity) is 1 minus the false negative rate. Specificity is the proportion of correctly identified true negative results and this is 1 minus the false positive rate. It is calculated as follows: A good diagnostic test would have both high specificity and high sensitivity, which means the number of times the test is likely to give an incorrect result is low. In practice, as the level of either sensitivity or specificity rises, the other falls, so a balance must be struck. The sensitivity and specificity of diagnostic tests commonly used to detect dental caries are shown in Table 1-1. Table 1-1 The sensitivity and specificity of diagnostic tests commonly used to detect dental caries. Test Sensitivity Specificity Visual examination 0.38 0.99 Transillumination 0.67 0.97 Radiographs 0.59 0.96 Laser 0.76-0.87 0.72-0.87 Electrical conductance 0.80-0.97 0.56-0.89 Visual Examination
Visual examination of a tooth is the most widely used method of diagnosing dental caries. This method is, however, incredibly inaccurate. The use of a probe, blunt or otherwise, is contraindicated as it is a poor test of the presence of caries and likely to cause cavitation of an early demineralised lesion. Probes should therefore be used to remove soft depo-sits only during a clinical examination. Whilst cavitation is quite easy to diagnose, looking for discolouration, which is suggestive of caries, is more difficult (Fig 1-3). The operator’s ability to see discolouration depends on the nature and direction of the illumination and whether magnification is used or not. Radiographs are useful aids in confirming a clinical suspicion of caries, especially proximal caries (Fig 1-4). When radiographs are used to confirm the presence of occlusal caries, however, superimposition of the cuspal pattern can be a problem, which makes their use for detecting early occlusal caries somewhat limited. Fig 1-3 Frank occlusal caries with cavitation in 36. Fig 1-4 Radiographs of a new patient, which emphasize the benefit of baseline bitewing radiography. Transillumination
This technique uses an intense beam of white light to transilluminate the tooth (Fig 1-5). The tip of the light is placed on the buccal or lingual surface of the tooth and as caries has a lower index of transmitted light it shows as darkening of the tooth (Figs 1-6–1-7). This technique can be used to detect proximal caries in anterior teeth and selected posterior teeth and may be useful in the diagnosis of cracked tooth syndrome (Figs 1-8 –1-9). The light units used for transillumination typically have an output of 2,000 lux generated from a 150 watt lamp with a tip diameter of 0.5 mm. The units are relatively inexpensive and, given the increasing number of fibre optic handpieces, it would be feasible to have a fibre optic tip attached to dental units. Special equipment is not required for the transillumination of anterior teeth. The beam of light from the operating light can be redirected with a hand mirror to transilluminate anterior teeth. The high sensitivity seen with this technique, arguably greater than when radiographs are used, offers practitioners a promising non-interventive technique for caries diagnosis. Fig 1-5 Light for transillumination of teeth. Fig 1-6 Transillumination of distal aspect of 35 showing distal caries. Fig 1-7 Radiograph confirming presence of caries distally in 35. Fig 1-8 Transillumination of 21 and 22 showing caries distally in 21 and mesially in 22. Fig 1-9 Radiograph confirming presence of caries distally in 21 and mesially in 22 detected by transillumination. Radiography
Radiographs are useful for the following: To confirm a clinical suspicion of proximal caries. To detect early non-cavitated proximal lesions, which are amenable to preventive care. For serial monitoring of lesions to look for evidence of disease activity. To provide an indication of the size and extent of the lesion, remembering that clinically the lesion will always be more extensive. The aim when using radiographs is really to separate lesions, if present, into those which require restorative therapy as distinct from those which will respond to preventive regimes (Fig 1-10). Fig 1-10 Radiograph showing lesions to be monitored in distal of 24 and mesial 25 and one which requires restorative therapy in distal of 35. For the detection of caries, intraoral radiographs, specifically bitewing radiographs for posterior teeth and periapical radiographs for anterior teeth, are the only radiographs that should be used. Extraoral radiographs (for example, panoramic radiographs) have no place in the diagnosis of caries, as they can be misleading and wildly inaccurate (Figs 1-11–1-12). Fig 1-11 Part of a DPT suggesting caries is present in mesial of 44. Fig 1-12 Intra-oral radiograph, which confirms that 44 is sound. All new patients should have bitewing radiographs taken at their first appointment to confirm the presence or absence of dental caries and to give an indication of bone levels. These radiographs act as a baseline against which other radiographs can be compared. The interval before repeat radiographs are taken depends primarily on the caries risk assessment of the patient. This gives the practitioner a guide as to whether lesions are progressing (Figs 1-13–1-14). To facilitate comparisons with subsequent radiographs, all bitewing radiographs should be taken with a film holder, which will make the beam angulation used more consistent. The use of faster films, which result in less radiation exposure to the patient, has resulted in radiographs which are not as sharp as slower films. This makes identification of early lesions more demanding, although the use of an x-ray magnifier is helpful. It is, however, difficult ethically to justify the use of slower films when faster films are available and it is recommended that practitioners consider changing to faster films for this reason. Fig 1-13 Bitewing radiograph of 37 showing a mesial lesion in a low-caries-risk individual. Fig 1-14 Bitewing of 37 taken six months later showing the lesion has...