This chapter provides an overview of the process through which a clinician completes patient assessment, clinical examination, diagnosis, and treatment plan for operative dentistry procedures. The chapter assumes that the reader has a background in oral medicine and an understanding of how to perform complete extraoral hard and soft tissue examinations along with intraoral cancer screening, as well as an understanding of the etiology, characteristics, risk assessment, and nonoperative management of dental caries as presented in Chapter 2. It is not in the scope of this chapter to incorporate the details of other aspects of a complete dental examination, including periodontal examination, occlusal examination, and esthetic evaluation.
Any discussion of diagnosis and treatment must begin with an appreciation of the role of the dentist in helping patients maintain their oral health. This role is summarized by the Latin phrase “primum non nocere,” which means “do no harm.” This phrase represents a fundamental principle of the healing arts over many centuries.
The implication of this concept for operative dentistry is that before we recommend treatment, we must be reasonably confident that the patient will be better off as a result of our intervention. However, how can we be reasonably confident when we realize that few, if any, of the tests we perform or the assessments of risk that we make are completely accurate? To make matters even more challenging, none of the treatments we provide is without adverse outcomes and none will likely last for the life of the patient. The answer is that we must acknowledge that the information or evidence we have is not perfect and that we must be clear about the possible consequences of our decisions. If we are as informed and clear about the options and their consequences, then we reduce the chances of doing any harm.
The success of operative treatment depends heavily on an appropriate plan of care, which, in turn, is based on a comprehensive analysis of the patient’s reasons for seeking care and on a systematic assesssment of the patient’s current conditions and risk for future problems. This information is then combined with the best available evidence on the approaches to managing the patient’s needs so that an appropriate plan of care can be offered to the patient.
The collection of this information and the determinations based on these findings should be comprehensive and occur in a stepwise manner. Simply put, skipping steps can lead to overlooking potentially important parts of the patient’s individual needs. These steps include reasons for seeking care, medical and dental histories, clinical examination for the detection of abnormalities, establishing diagnoses, assessing risk, and determining prognosis. All of these steps must occur before a sound and appropriate plan of care can be recommended.
Growing attention to using only the most effective and appropriate treatment has spawned interest in numerous activities. Research that provides information on treatments that work best in certain situations is expanding the knowledge base of dentistry and has led to an interest in translating the results of that research into practice activities and enhanced care for patients. This movement has been termed evidence-based dentistry and is defined as the “conscientious, explicit, and judicious use of current best evidence in making decisions about the care of individual patients.”1 Systematic reviews emerging from the focus on evidence-based dentistry will provide practitioners with a distillation of the available knowledge about various conditions and treatments. Currently, the American Dental Association (ADA) has developed a Web site (http://ebd.ada.org/) that can be used by dental professionals for evidence-based dentistry decision making. This Web site helps clinicians identify systematic reviews, describes the preferred method for assembling the best available scientific evidence, and provides an appraisal of the evidence through critical summaries. As evidence-based dentistry continues to expand, professional associations will become more active in the development of guidelines to assist dentists and their patients in making informed and appropriate decisions.
Clinical examination is the “hands-on” process of observing the patient’s oral structures and detecting signs and symptoms of abnormal conditions or disease. This information is used to formulate diagnoses, which are a determination or judgment of health versus disease and variations from normal. During the clinical examination, the dentist must be keenly sensitive to subtle signs, symptoms, and variations from normal to detect pathologic conditions and etiologic factors. Meticulous attention to detail generates a base of information for assessing the patient’s general physical health and diagnosing specific dental problems.
Before initiating any treatment, the patient’s chief concerns, or the problems that initiated the patient’s visit, should be obtained. Concerns are recorded essentially verbatim in the dental record. The patient should be encouraged to discuss all aspects of the current problems, including onset, duration, symptoms, and related factors. This information is vital to establishing the need for specific diagnostic tests, determining the cause, selecting appropriate treatment options for the concerns, and building a sound relationship with the patient.
The patient or legal guardian completes a standard, comprehensive medical history form. This form is an integral part of the pre-examination patient interview, which helps identify conditions that could alter, complicate, or contraindicate proposed dental procedures. The practitioner should identify (1) communicable diseases that require special precautions, procedures, or referral; (2) allergies or medications, which can contraindicate the use of certain drugs; (3) systemic diseases, cardiac abnormalities, or joint replacements, which require prophylactic antibiotic coverage or other treatment modifications; and (4) physiologic changes associated with aging, which may alter clinical presentation and influence treatment. The practitioner also might identify a need for medical consultation or referral before initiating dental care. All of this information is carefully detailed in the patient’s permanent record and is used, as needed, to shape subsequent treatment.
The dental history is a review of previous dental experiences and current dental problems. Review of the dental history often reveals information about past dental problems, previous dental treatment, and the patient’s responses to treatments. Frequency of dental care and perceptions of previous care may be indications of the patient’s future behavior. If a patient has difficulty tolerating certain types of procedures or has encountered problems with previous dental care, an alteration of the treatment or environment might help avoid future complications. Also, this discussion might lead to identification of other problems such as areas of food impaction, inability to floss, areas of pain, and broken restorations or tooth structure. It is crucial to understand past experiences to provide optimal care in the future. Finally, the date and type of available radiographs should be recorded to ascertain the need for additional radiographs and to minimize the patient’s exposure to unnecessary ionizing radiation.
Clinical dentistry often requires the viewing and evaluation of small details in teeth, intraoral and perioral tissues, restorations, and study casts. Unaided vision is often inadequate to view details needed to make treatment decisions. Magnification aids such as loupes provide a larger image size for improved visual acuity, while allowing proper upright posture to be maintained with less eye fatigue.
When choosing loupes, several parameters should be considered.2,3,4 Magnification (power) describes the increase in image size. Most dentists use magnifications of 2× to 4×. The lower power systems of 2× to 2.5× allow multiple quadrants to be viewed, whereas the higher power systems of 3× to 4× enable viewing of several teeth or a single tooth. In general, higher magnification systems are heavier, have a narrower field of view, are more expensive, and require more light than lower power systems. The use of small, lightweight LED (light-emitting diode) headlamps attached to the eyeglass frame or attached to a headband offer the considerable visual advantage of added illumination when used with loupes.
Working distance (focal length) is the distance from the eye to the object when the object is in focus. This parameter should be considered carefully before selecting loupes because the desired working distance depends on the dentist’s height, arm length, and seating preferences. Dentists of average height typically choose a working distance of 13 to 14 inches (33–35 cm), whereas tall dentists and those who prefer to work farther away from the patient use working distances of 14 to 16 inches (35–40 cm).
Depth of focus, or the difference between the far and near focus limits of the working distance, depends on the magnification. Typically, the lower the magnification, the greater is the depth of focus.
Many choices of magnification loupes are currently available for dentistry. The simplest magnifiers are the diopter single-lens loupes, which are single-piece plastic pairs of lenses that clip onto eyeglass frames. These loupes are inexpensive and lightweight and can provide magnification of up to 2.5×. However, images can be distorted, and working lengths can be less than ideal. The more commonly used dental loupe is the binocular loupe with lenses mounted on an eyeglass frame. Binocular loupes typically have Galilean and prismatic optics that provide 2× to 3.5× magnification or even 4× and greater magnification. Prescription lenses can be fitted in the eyeglass frames for all loupe types. Most models also have side shields or a wraparound design for universal precautions and ease of infection control. Two mounting systems are currently available for binocular loupes: (1) flip-up and (2) fixed or through-the-lens.
Previously limited primarily to endodontic practices, dental microscopes now are being used in some restorative dentistry practices. Compared with high-powered loupes, dental microscopes allow the clinician to view intraoral structures at a higher level of magnification while maintaining a broader field of view. Because very small areas can be seen, microscopes are used in detail-oriented procedures such as the finishing of porcelain restoration margins, identifying minute decay, and minimizing the removal of sound tooth structure. Generally, microscopes include five or six magnification stops that typically range from 2.5× to 20×. The largest manufacturers of dental microscopes include Carl Zeiss, Inc. (Dublin, CA); Global Surgical Corporation (St. Louis, MO); and Seiler Precision Microscope Instrument Company (St. Louis, MO). Cost, size of the equipment, and perceived lack of value to the clinician have been factors in limiting the use of microscopes in operative dentistry practice.
Photography in dentistry has many uses and with newer digital technologies, photography is becoming mainstream in dental practice. Just as radiographs provide a historical look at a patient’s situation, photography is an excellent tool for documentation and evaluation. Intraoral cameras and SLR (single-lens reflex) digital cameras that are easy to use provide opportunities to document existing esthetic conditions such as color, shape, and position of teeth. Close-up images of existing pits and fissures can provide the opportunity to see changes that cannot be documented in any other way for re-evaluation in the future. Photographs of preparations of deep caries lesions provide documentation to aid in future diagnosis of tooth conditions. Without preparation photographic documentation, this information would no longer be available once the restoration has been placed. Digital documentation with photographs is easier and more cost effective with the current quality of digital photography and ability to process and store images in an electronic patient record.
This section describes examination, diagnosis, risk assessment, and prognosis. It details the examination of teeth and restorations using visual examination, radiographic examination, and adjunctive aids to detect caries and assess the structural integrity of teeth. Also described is the examination of occlusion and esthetics as related to operative dentistry procedures.
The diagnostic effort of health care professionals has been enhanced by the use of principles adopted from clinical epidemiology. This analytic approach relies on “2 × 2” contingency tables (Fig. 3-1) derived from clinical trials data. Such studies compare the results of a diagnostic test with the results obtained from a “gold standard” (knowledge of the actual condition) to determine how well a test identifies the “true,” or actual, condition. The results of the diagnostic test, positive or negative, are shown across the rows of the table, and the results of a “gold standard” or the “truth” are displayed in the columns. Cell A of the table contains the cases that the test identifies as being positive (or diseased) that actually are positive (i.e., confirmed by the “gold standard”). These cases are termed true positives. Cell B contains all cases for which a positive finding from the diagnostic test is present, but where the actual condition is negative. Therefore, this cell denotes false positives. Cell C includes the cases identified by the diagnostic test as not being diseased, but actually are diseased, as determined by the “gold standard.” Findings in this cell are termed false negatives. The final cell, cell D, includes true negatives, where the diagnostic test accurately identifies nondiseased cases that are truly negative as confirmed by the “gold standard.” A perfect diagnostic test would result in all cases being assigned to cells A or D with no false positives (cell B) or false negatives (cell C).
When the basics of this table are understood, the information it yields can be put to good use by the diagnostician. The first concept is test sensitivity, which is calculated as the number of true positives (A) divided by the number of total positive cases (A + C). The term sensitivity indicates the proportion of individuals with disease in any group or population that is identified positively by the test. In contrast, specificity refers to the proportion of individuals without disease properly classified by the diagnostic test and is the ratio of true negatives (D) to all negatives (B + D). Sensitivity and specificity will not vary on the basis of the prevalence of disease, that is, the proportion of cases in a population. Rather, these statistics indicate what proportions of existing disease and absence of disease will be correctly identified in any group of individuals.
A test with low sensitivity indicates that a high probability exists that many of the individuals with negative results have the disease and go undiagnosed. Conversely, a test with high sensitivity means that most of those who actually have disease will be identified as such. Tests with high specificity suggest that patients without the disease are highly likely to test negative. Tests with low specificity will misclassify a sizable proportion as diseased when many are really free of disease.
Very few tests have both high sensitivity and high specificity, so trade-offs are inevitable. The clinician must weigh the seriousness of the disease that is left untreated (in cases of low sensitivity) against the invasiveness of the treatment (in cases of low specificity). In the former, low sensitivity may be acceptable for tests diagnosing slowly progressing, non-fatal conditions but unacceptable for conditions that progress rapidly or are life threatening. In the latter, low specificity may not be acceptable if the treatment is invasive and irreversible, but more acceptable if the treatment is non-invasive and temporary. In the case of dental caries, all things being equal, this means that the clinician can accept a less sensitive test (i.e., miss some initial lesions [cell C]) because caries usually progresses slowly over years. But given that operative treatment is invasive and irreversible, a highly specific test (i.e., few false positives [cell B]) means that fewer healthy teeth will be treated.
These concepts are widely used in medical practice. Although many of the necessary studies have not been conducted to develop these probabilities for dental conditions, interest in the use of clinical epidemiology in the dental profession has been growing. In the future, more studies will be conducted to provide this information to clinicians, and one should be prepared to take advantage of their use.
A trained assistant familiar with the terminology, notation system, and charting procedure can survey the patient’s teeth and existing restorations and record the information to save chair time for the dentist. The dentist subsequently performs the examination, confirms the charting, makes a diagnosis, establishes a risk assessment profile for the patient, establishes a prognosis, and develops the treatment plan in conjunction with the patient’s current needs and desires. The clinical examination is performed systematically in a clean, dry, well-illuminated mouth. Proper instruments, including a mirror, an explorer, and a periodontal probe, are required. A routine for charting should be established, such as starting in the upper right quadrant with the most posterior tooth and progressing around the maxillary and mandibular arches. An accurate examination is possible only when teeth are clean and dry. This may require initial scaling, flossing, and a toothbrushing prophylaxis before final clinical examination of teeth. A cotton roll in the vestibular space and another under the tongue maintain dryness and improve vision (Fig. 3-2). Dental floss is useful in identifying overhanging restorations, improper proximal contours, and open contacts.
Contemporary caries management, which encompasses expanded non-operative approaches and conservative operative interventions, relies on enhanced risk assessment and improved lesion detection and classification. The objective of improved detection and classification systems is to accurately identify those early enamel lesions that are most likely to be reversed and remineralized. Therefore, appropriate non-operative care can be attempted, and lesions that require operative treatment can be identified as early as possible in the disease process. With this approach, the restoration will result in the removal of the minimum amount of tooth structure.
Caries lesions can be detected by visual changes in tooth surface texture or color or in tactile sensation when an explorer is used judiciously to detect surface roughness by gently stroking across the tooth surface. Current thinking finds that the use of an explorer in this manner might have some relevance for assessing caries activity. However, it cannot be over-emphasized that the explorer must not be used to determine a “stick,” or a resistance to withdrawal from a fissure or pit. This improper use of a sharp explorer has been shown to irreversibly damage the tooth by turning a sound, remineralizable sub-surface lesion into a possible cavitation that is prone to progression. Forcing an explorer into pits and fissures also theoretically risks cross-contamination from one probing site to another. In contrast, for assessment of root caries, an explorer is valuable to evaluate root surface softness. Additional methods used in caries detection are radiographs that show changes in tooth density from normal and adjunctive tests that use various technologies to aid in caries lesion detection and caries activity.
Caries lesions are most prevalent in the faulty pits and fissures of the occlusal surfaces where the developmental lobes of posterior teeth failed to coalesce, partially or completely (Fig. 3-3). It is important to remember the distinction between primary occlusal grooves and fossae and occlusal fissures and pits. Primary occlusal grooves and fossae are smooth “valley or saucer” landmarks indicating the region of complete coalescence of developmental lobes. Normally, such grooves and fossae are not susceptible to caries because they are not niches for biofilm and frequently are cleansed by the rubbing action of food during mastication. Conversely, occlusal fissures and pits are deep, tight crevices or holes in enamel, where the lobes failed to coalesce partially or completely. Fissures and pits are detected visually.
As noted earlier, sharp explorers were used to diagnose fissure caries. However, numerous studies have found that the use of a sharp explorer for this purpose did not increase diagnostic validity compared with visual inspection alone.5–8 The use of the dental explorer for this purpose was found to fracture enamel and serve as a source for transferring pathogenic bacteria among various teeth.9,10 Therefore, the use of a sharp explorer in diagnosing pit-and-fissure caries is contraindicated as part of the detection process.
An occlusal surface is examined visually and radiographically.11,12 The visual examination is conducted in a dry, well-illuminated field. Through direct vision and reflecting light through the occlusal surface of the tooth, the occlusal surface is diagnosed as diseased if chalkiness or apparent softening or cavitation of tooth structure, forming the fissure or pit, is seen or a brown-gray discoloration, radiating peripherally from the fissure or pit, is present. In contrast, a nondiseased occlusal surface has either grooves or fossae that have shallow tight fissures, which exhibit superficial staining with no radiographic evidence of caries. The superficial staining is extrinsic and occurs over several years of oral exposure in a person with low caries risk. Pre-carious or carious pits are occasionally present on cusp tips (see Fig. 3-3, A). Typically, these are the result of developmental enamel defects or following loss of enamel from tooth due to erosion or abrasion. Carious pits and fissures also occur on the occlusal two thirds of the facial or lingual surface of posterior teeth and on the lingual surface of maxillary incisors. Occlusal enamel can be evaluated for loss of translucency and changes in color, which may be characteristic of a caries lesion (see Fig. 3-3, B). The color change can be dark gray and should not be confused with the noncarious fissures and pits that often become merely stained over time. These visual techniques of examining teeth are then translated into the codes used in the International Caries Detection and Assessment System (ICDAS).
Clinical caries lesion detection has been found lacking and improvement is needed.13 One means of addressing these concerns has been the development of a visual system for caries lesion detection and classification. The ICDAS was developed to serve as a guide for standardized visual caries assessment that could be used for clinical practice, clinical research, education, and epidemiology (Fig. 3-4). In the United States, the Caries Management by Risk Assessment (CAMBRA) movement, as discussed in Chapter 2 on cariology, embraces the principles of the ICDAS for visual examination and assessment of caries lesions.
The clinical examination for detecting caries lesions is aided by an assessment of the patient’s overall caries risk, along with the patient’s patterns of susceptibility. The patient’s medical history, dental history, oral hygiene, diet, and age, among other caries risk factors and indicators, can suggest a prediction of current and future caries activity. For example, caries lesions also tend to occur bilaterally and on adjacent proximal surfaces (see Fig. 3-3). During the clinical examination, every accessible surface of each tooth must be inspected for localized changes in color, texture, and translucency, as described in the ICDAS codes. This requires two minimum conditions for the examination to be properly conducted: (1)Teeth must be sufficiently air-dried so that the changes can be seen properly, and (2) biofilm or plaque must be thoroughly removed from teeth prior to the examination. The ICDAS uses a two-stage process to record the status of the caries lesion. The first is a code for the restorative status of the tooth, and the second is for the severity of the caries lesion. The status of the caries severity is determined visually on a scale of 0 to 6:
See Fig. 3-4 for the ICDAS for examples of coding for restorative status and caries severity. The details of this system for detection and training to use the system with an online tutorial are available at www.icdas.org.
Proximal surface caries, one form of smooth-surface caries, is usually diagnosed radiographically (Fig. 3-5, A). It also can be detected by careful visual examination after tooth separation or through fiberoptic transillumination.14 When caries has invaded proximal surface enamel and has demineralized dentin, a white chalky appearance or a shadow under the marginal ridge may become evident (see Fig. 3-5, C). Careful probing with an explorer on the proximal surface may detect cavitation, which is defined as a break in the surface contour of enamel. The use of all examination methods is helpful in arriving at a final diagnosis.
Brown spots on intact, hard proximal surface enamel adjacent to and usually gingival to the contact area are often seen in older patients, in whom caries activity is low. These discolored areas are a result of extrinsic staining during earlier caries demineralizing episodes, each followed by a remineralization episode. These areas are no longer carious and are usually more resistant to caries as a result of fluorohydroxyapatite formation. Restorative treatment is not indicated. These inactive caries lesions sometimes challenge the diagnosis because of faint radiographic evidence of the remineralized lesion.
Proximal surface caries in anterior teeth can be identified by radiographic examination, visual inspection (with optional transillumination), or probing with an explorer. Transillumination is accomplished by placing the mirror or light source on the lingual aspect of teeth and directing the light through teeth. Proximal surface caries, if other than early enamel lesions, appears as a dark area along the marginal ridge when the light is directed through the tooth. In addition to transillumination, tactile exploration of anterior teeth is appropriate to detect cavitation because the proximal surfaces generally are more visible and accessible than in the posterior regions. Small early enamel lesions may be detectable only on the radiograph.
Another form of smooth-surface caries can occur on the facial and lingual surfaces of the teeth of patients with high caries activity, particularly in the cervical areas that are less accessible for cleaning. The earliest clinical evidence of early enamel lesions on these surfaces is a white spot that is visually different from the adjacent translucent enamel and partially or totally disappears with wetting. Drying again causes it to reappear. This disappearing–reappearing phenomenon distinguishes the smooth-surface early enamel lesion from the white spot resulting from nonhereditary enamel hypocalcification (see section on clinical examination for additional defects). Both types of white spots are undetectable tactilely because the surface is intact, smooth, and hard. For white spot lesions, nonsurgical remineralization therapies (discussed in Chapter 2) should be instituted to promote remineralization.
The presence of several facial (or lingual) smooth-surface caries lesions within a patient’s dentition suggests a high caries rate, which means that if the existing risk factors are not addressed, the patient is at high risk for developing more lesions in the future. In a caries-susceptible patient, the gingival third of the facial surfaces of maxillary posterior teeth and the gingival third of the facial and lingual surfaces of mandibular posterior teeth should be evaluated carefully because these surfaces are often at a greater risk for caries. Advanced smooth-surface caries exhibits discoloration and demineralization and feels soft to penetration by the explorer. The discoloration can range from white to dark brown, with rapidly progressing caries usually being light in color. With slowly progressing caries in a patient with low caries activity, darkening occurs over time because of extrinsic staining, and remineralization of the decalcified tooth structure occasionally may harden the lesion. Such an arrested lesion at times may be rough, although cleanable, and a restoration is not indicated except to address the esthetic concerns of the patient. The dentin in an arrested remineralized lesion is sclerotic. These lesions are inactive lesions but remain susceptible to new caries activity in the future.
In patients with attachment loss, extra care must be taken to inspect for root-surface caries. A combination of root exposure, dietary changes, systemic diseases, and medications that affect the amount and character of saliva can predispose a patient, especially an older individual, to root-surface caries. Lesions are often found at the cementoenamel junction (CEJ) or more apically on cementum or exposed dentin in older patients or in patients who have undergone periodontal surgery (see Fig. 3-3, F). Early in its development, root caries appears as a well-defined, discolored area adjacent to the gingival margin, typically near the CEJ. Root caries is softer than the adjacent tissue, and typically lesions spread laterally around the CEJ. Although no clinical criteria are universally accepted for the diagnosis of root caries, it is generally agreed that softened cemental or dental tooth structure compared with the surrounding surface is characteristic.15 Active root caries is detected by the presence of softening and cavitation.16,17 Although root-surface caries may be detected on radiographic examination, a careful, thorough clinical examination is crucial. A difficult diagnostic challenge is a patient who has attachment loss with no gingival recession, limiting accessibility for clinical inspection. These rapidly progressing lesions are best diagnosed using vertical bitewing radiographs. Differentiation of a caries lesion from cervical burnout radiolucency is, however, essential.18
In addition to the traditional methods of caries detection, several new technologies have emerged and show promising results for the clinical detection and diagnosis of caries lesions. These devices may have the potential to replace the tactile portion of caries detection, where explorers are used to try to estimate the depth of the caries lesions into the pits and fissures. These devices have two limitations. The first is that they are only indicated for use on unrestored pits and fissures. The second is that their diagnostic accuracy has not been firmly established. The technologies currently approved by the U.S. Food and Drug Administration (FDA) include laser-induced fluorescence, light-induced fluorescence, and AC impedance spectroscopy.11,19
The DIAGNOdent device (KaVo Dental Corporation, Charlotte, NC) uses laser fluorescence technology, with the intention of detecting and measuring bacterial products and changes in the tooth structure in a caries lesion. This compact and portable device, which requires a clean, dry occlusal surface, yields a numerical score from 0 to 99. The manufacturer has recommended threshold scores that represent the presence and extent of a lesion. A systematic review found that the “device is clearly more sensitive than traditional diagnostic methods, but the increased likelihood of false-positive diagnoses limits its usefulness as a principal diagnostic method.”20
Another system currently available for caries lesion detection is the Spectra Camera (Air Techniques, Melville, NY). The Spectra system claims to detect caries lesions by measuring increased light-induced fluorescence. Special LEDs project high-energy violet or blue light onto the tooth surface. Light of this wavelength supposedly stimulates porphyrins—metabolites unique to cariogenic bacteria—to appear distinctly red, while healthy enamel fluoresces to appear green. Using this fluorescent technology, the data captured by the Spectra system are analyzed by imaging software, which highlights the lesions in different color ranges and defines the potential caries activity on a scale of 0 to 5. Although this technology appears promising, as of the publication date of this textbook, no peer-reviewed randomized clinical trials have been reported.
The CarieScan PRO (CarieScan, LLC, Charlotte, NC) is a device for the detection and monitoring of caries by the application and analysis of AC (alternating current) impedance spectroscopy (ACIST). The CarieScan PRO claims to enable clinicians to evaluate demineralized tooth structure using ACIST by providing information about tissue being healthy, in the early stages of demineralization, or already significantly decayed. The device provides a color scale and a numerical scale to determine the severity of the caries lesion and is accompanied by management recommendations that range from therapeutic prevention to operative intervention appropriate for the extent of the demineralization.
As described earlier, an ideal diagnostic test accurately detects when a tooth surface is healthy (specificity); when a lesion or demineralization is present (sensitivity); and if demineralization is present, whether or not it is active and whether or not it has cavitated the surface. Except for the presence of frank cavitation and more advanced lesions, none of the available approaches to detecting caries or determining lesion activity is completely accurate. Thus, the clinician must take all of the available diagnostic information together—visual, tactile, radiographic, and so on—along with the respective reported levels of accuracy and combine that with an assessment of the patient’s overall caries status to make a final diagnosis to the presence and extent of a caries lesion.
After the clinical examination for detection of caries lesions is completed, the management and treatment of caries lesions discovered depends not only on a thorough assessment of the present activity of the lesions but also on an understanding of the future risk of the patient for increased activity of the lesions. Therefore, the next step is to determine the present activity of the lesions. Is the lesion progressing, or is the lesion arrested? If the lesion is determined to be progressing and the patient’s risk factors are not changed, some intervention, either surgical or nonsurgical, is indicated. If the lesion is determined to be arrested, or not progressing, and the risk factors have been controlled, no treatment is needed other than regular preventive dental care. Currently, a reliable and accurate gold standard test based on one examination at one point in time to accurately assess caries lesion activity is not available, so it is important for the clinician to use information from all the tests and risk assessment to judge which type of intervention is appropriate at the current time. The decision of surgical intervention or nonintervention carries some risk for the patient in either direction, but studies would conclude that all diagnostic doubts should benefit the tooth by choosing non-operative options over irreversible operative dentistry options.
Evaluation of existing restorations should be accomplished systematically in a clean, dry, well-lit field. Clinical evaluation of amalgam restorations requires visual observation, application of tactile sense with the explorer, use of dental floss, interpretation of radiographs, and knowledge of the probabilities that a given condition is sound or at risk for further breakdown. At least 11 distinct conditions might be encountered when amalgam restorations are evaluated: (1) amalgam “blues,” (2) proximal overhangs, (3) marginal ditching, (4) voids, (5) fracture lines, (6) lines indicating the interface between abutted restorations, (7) improper anatomic contours, (8) marginal ridge incompatibility, (9) improper proximal contacts, (10) improper occlusal contacts, and (11) recurrent caries lesions.
Discolored areas or “amalgam blues” are often seen through the enamel in teeth that have amalgam restorations. This bluish hue results either from the leaching of amalgam corrosion products into the dentinal tubules or from the color of underlying amalgam seen through translucent enamel. The latter occurs when the enamel has little or no dentin support, such as in undermined cusps, marginal ridges, and regions adjacent to proximal margins. When other aspects of the restoration are sound, amalgam blues do not indicate caries, do not warrant classifying the restoration as defective, and require no further treatment. Replacement of the restoration may be considered, however, for elective improvement of esthetics or for areas under heavy functional stress that may require a cusp capping restoration to prevent possible tooth fracture.
Proximal overhangs are diagnosed visually, tactilely, and radiographically (Fig. 3-6). The amalgam–tooth junction is evaluated by moving the explorer back and forth across it. If the explorer stops at the junction and then moves outwardly onto the amalgam, an overhang is present. Overhangs also can be confirmed by the catching or tearing of dental floss. Such an overhang can provide an obstacle to good oral hygiene and result in inflammation of adjacent soft tissue. If it causes problems, an overhang should be corrected, and this often indicates the need for restoration replacement.
Marginal gap or ditching is the deterioration of the amalgam–tooth interface as a result of wear, fracture, or improper tooth preparation (Fig. 3-7, A). It can be diagnosed visually or by the explorer dropping into an opening as it crosses the margin. Shallow ditching less than 0.5 mm deep usually is not a reason for restoration replacement because such a restoration usually looks worse than it really is.21 The eventual self-sealing property of amalgam allows the restoration to continue serving adequately if it can be satisfactorily cleaned and maintained. If the ditch is too deep to be cleaned or jeopardizes the integrity of the remaining restoration or tooth structure, the restoration should be replaced.12 In addition, secondary caries is frequently found around marginal gaps near the gingival wall and warrants replacement.22
Voids that are usually localized and are caused by poor condensation of the amalgam can also occur at the margins of amalgam restorations. If the void is at least 0.3 mm deep and is located in the gingival third of the tooth crown, the restoration is judged as defective and should be repaired or replaced. Accessible small voids in other marginal areas where the enamel is thicker may be corrected by recontouring or repairing with a small restoration.
A careful clinical examination detects any fracture line across the occlusal portion of an amalgam restoration. A line that occurs in the isthmus region generally indicates fractured amalgam, and the defective restoration that must be replaced (Fig. 3-8, A). Care must be taken to correctly evaluate any such line, however, especially if it is in the mid-occlusal area because this may be an interface line, a manifestation of two abutted restorations accomplished at separate appointments (see Fig. 3-8, B). If other aspects of the abutted restorations are satisfactory, replacement is unnecessary.
Amalgam restorations should duplicate the normal anatomic contours of teeth. Restorations that impinge on soft tissue, have inadequate embrasure form or proximal contact, or prevent the use of dental floss should be classified as defective, indicating recontouring or replacement (see Fig. 3-7, B).
The marginal ridge portion of the amalgam restoration should be compatible with the adjacent marginal ridge. Both ridges should be at approximately the same level and display correct occlusal embrasure form for passage of food to the facial and lingual surfaces and for proper proximal contact area. If the marginal ridges are incompatible and are associated with poor tissue health, food impaction, or the inability of the patient to floss, the restoration is defective and should be recontoured or replaced.
The proximal contact area of an amalgam restoration should touch the adjacent tooth (a “closed” contact) at the proper contact level and with correct embrasure form and possess the proper size. If the proximal contact of any restoration is suspected to be inadequate, it should be evaluated with dental floss or visually by trial angulations of a mouth mirror (held lingually when viewing from the facial aspect) to reflect light and see if a space at the contact (“open” contact) is present. For this viewing, the contact must be free of saliva. If the contact is open and is associated with poor interproximal tissue health, food impaction, or both, the restoration should be classified as defective and should be replaced or repaired. An open contact typically is annoying to the patients, so correcting the problem usually is an appreciated service.