1 HISTORY TAKING AND CLINICAL EXAMINATION
Fixed prosthodontic treatment involves the replacement and restoration of teeth by artificial substitutes that are not readily removable from the mouth. Its focus is to restore function, esthetics, and comfort. Fixed prosthodontics can offer exceptional satisfaction for both patient and dentist. It can transform an unhealthy, unattractive dentition with poor function into a comfortable, healthy occlusion capable of years of further service and greatly enhance esthetics (Fig. 1-1A and B). Treatment can range from the fairly straightforward restoration of a single tooth with a cast crown (Fig. 1-1C) or replacement of one or more missing teeth with a fixed dental prosthesis (Fig. 1-1D) or implant-supported restoration to a highly complex restoration involving all the teeth in an entire arch or the entire dentition.
Fig. 1-1 A severely damaged maxillary dentition (A) restored with metal-ceramic fixed prostheses (B). C, Complete cast crown restores mandibular molar. D, Three-unit fixed dental prosthesis replacing missing mandibular premolar.
(C, Courtesy of Dr. X Lepe. D, Courtesy of Dr. J. Nelson.)
To achieve predictable success in this technically exacting and demanding field, there must be meticulous attention to every detail: from the initial patient interview and diagnosis, through the active treatment phases, and to a planned schedule of follow-up care. Otherwise, the result is likely to be unsatisfactory and frustrating for both dentist and patient, resulting in disappointment and loss of confidence in each other.
Problems encountered during or after treatment can often be traced to errors and omissions during history taking and initial examination. An inexperienced clinician may plunge into the treatment phase before collecting sufficient diagnostic information that helps predict likely pitfalls.
Making the correct diagnosis is prerequisite for formulating an appropriate treatment plan. This requires that all pertinent information be obtained. A complete history includes a comprehensive assessment of the patient’s general and dental health, individual needs, preferences, and personal circumstances. This chapter reviews fundamentals of history taking and clinical examination, with special emphasis on obtaining the necessary information to make appropriate fixed prosthodontic treatment decisions.
A patient’s history should include all pertinent information concerning the reasons for seeking treatment, along with any personal information, including relevant previous medical and dental experiences. The chief complaint should be recorded, preferably in the patient’s own words. A screening questionnaire (Fig. 1-2) is useful for history taking; it should be reviewed in the patient’s presence to correct any mistakes and to clarify inconclusive entries. If the patient is mentally impaired or a minor, the guardian or responsible parent must be present.
The accuracy and significance of the patient’s primary reason or reasons for seeking treatment should be analyzed first. These may be just the obvious features, and careful examination often reveals problems and disease of which the patient is unaware; nevertheless, the patient perceives the chief complaint as the major problem. Therefore, when a comprehensive treatment plan is proposed, special attention must be given to how the chief complaint can be resolved. The inexperienced clinician trying to prescribe an “ideal” treatment plan can lose sight of the patient’s wishes. The patient may then become frustrated because the dentist apparently does not understand or does not want to understand the patient’s point of view.
If pain is present, its location, character, severity, and frequency should be noted, as well as the first time it occurred, what factors precipitate it (e.g., hot, cold, or sweet things), and any changes in its character. Is it localized or more diffuse in nature? It is often helpful to have the patient point at the area while the dentist pays close attention.
Compromised appearance is a strong motivating factor for patients to seek advice as to whether improvement is possible (Fig. 1-3). Such patients may have missing or crowded teeth, or a tooth or restoration may be fractured. Their teeth may be unattractively shaped, malpositioned, or discolored, or there may be a developmental defect.
The patient’s name, address, phone number, sex, occupation, work schedule, and marital and financial status are noted. Much can be learned in a 5-minute, casual conversation during the initial visit. In addition to establishing rapport and developing a basis for the patient to trust the dentist, small and seemingly unimportant personal details often have considerable influence in establishing a correct diagnosis, prognosis, and treatment plan.
An accurate and current general medical history should include any medication the patient is taking, as well as all relevant medical conditions. If necessary, the patient’s physician or physicians can be contacted for clarification. The following classification may be helpful:
(Courtesy of Dr. P. B. Robinson.)
Fig. 1-5 A, Extensive damage caused by self-induced acid regurgitation. Note that the lingual surfaces are bare of enamel except for a narrow band at the gingival margin. B, Teeth prepared for partial-coverage restorations. C, Definitive cast. D and E, The completed restoration.
Dental offices practice “universal precautions” to ensure appropriate infection control. This means that full infection control is practiced for every patient; no additional measures are needed when dentists treat known disease carriers.6
Clinicians should be cautious when commenting before a thorough examination is completed. With adequate experience, a clinician can often assess preliminary treatment needs during the initial appointment. However, fairly assessing the quality of a previously rendered treatment can be difficult, because the circumstances under which the treatment was rendered are seldom known. When such an assessment is requested for legal proceedings, the patient should be referred to a specialist familiar with the “usual and customary” standard of care.
The patient’s oral hygiene is assessed, and current plaque-control measures are discussed, as are previously received oral hygiene instructions. The frequency of any previous débridement should be recorded, and the dates and nature of any previous periodontal surgery should be noted.
The patient’s restorative history may include only simple composite resin or dental amalgam fillings, or it may involve crowns and extensive fixed dental prostheses. The age of existing restorations can help establish the prognosis and probable longevity of any future fixed prostheses.
Patients often forget which teeth have been endodontically treated. These can be readily identified with radiographs. The findings should be reviewed periodically so that periapical health can be monitored and any recurring lesions promptly detected (Fig. 1-6).
Occlusal analysis should be an integral part of the assessment of a postorthodontic dentition. If restorative treatment needs are anticipated, they should be undertaken by the restorative dentist. Occlusal adjustment (reshaping of the occlusal surfaces of the teeth) may be needed to promote long-term positional stability of the teeth and reduce or eliminate parafunctional activity. On occasion, root resorption (detected on radiographs) (Fig. 1-7) may be attributable to previous orthodontic treatment. As the crown/root ratio is affected, future prosthodontic treatment and its prognosis may also be affected. Restorative treatment can often be simplified by minor tooth movement. When a patient is contemplating orthodontic treatment, considerable time can be saved if minor tooth movement (for restorative reasons) is incorporated from the start. Thus, good communication between the restorative dentist and the orthodontist may prove very helpful.
The patient’s experiences with removable prostheses must be carefully evaluated. For example, a partial removable dental prosthesis may not have been worn for a variety of reasons, and the patient may not even have mentioned its existence. Careful questioning and examination usually elicits discussion concerning any such devices. Listening to the patient’s comments about previously unsuccessful removable prostheses can be very helpful in assessing whether future treatment will be more successful.
Information about missing teeth and any complications that may have occurred during tooth removal is obtained. Special evaluation and data collection procedures are necessary for patients who require prosthodontic care after orthognathic surgery. Before any treatment is undertaken, the prosthodontic component of the proposed treatment should be fully coordinated with the surgical component.
Previous radiographs may prove helpful in judging the progress of dental disease. They should be obtained if possible, because it is generally better to avoid exposing the patient to unnecessary ionizing radiation. Dental practices usually forward radiographs or acceptable duplicates promptly on request. In most instances, however, a current diagnostic radiographic series is essential and should be obtained as part of the examination.
A history of pain or clicking in the TMJs or neuromuscular symptoms, such as tenderness to palpation, may be caused by TMJ dysfunction, which should normally be treated and resolved before fixed prosthodontic treatment begins. A screening questionnaire efficiently identifies these problems. The patient should be questioned regarding any previous treatment for joint dysfunction (e.g., occlusal devices, medications, biofeedback, or physical therapy exercises).
An examination consists of the clinician’s use of sight, touch, and hearing to detect conditions outside the normal range. To avoid mistakes, it is critical to record what is actually observed rather than to make diagnostic comments about the condition. For example, “swelling,” “redness,” and “bleeding on probing of gingival tissue” should be recorded, rather than “gingival inflammation” (which implies a diagnosis).
The patient’s general appearance, gait, and weight are assessed. Skin color is noted for signs of anemia or jaundice. Vital signs, such as respiration, pulse, temperature, and blood pressure, are measured and recorded. Fixed prosthodontic treatment is often indicated in middle-aged or older patients, who can be at higher risk for cardiovascular disease. Relatively inexpensive cardiac monitoring units are available for in-office use (Fig. 1-8). Patients with vital sign measurements outside normal ranges should be referred for a comprehensive medical evaluation before definitive treatment is initiated.
Special attention is given to facial asymmetry because small deviations from normal may hint at serious underlying conditions. Cervical lymph nodes are palpated, as are the TMJs and the muscles of mastication.
The clinician locates the TMJs by palpating bilaterally just anterior to the auricular tragi while the patient opens and closes the mouth. This permits a comparison between the relative timing of left and right condylar movements during the opening stroke. Asynchronous movement may indicate an anterior disk displacement that prevents one of the condyles from making a normal translatory movement (see Chapter 4). Auricular palpation (Fig. 1-9) with light anterior pressure helps identify potential disorders in the posterior attachment of the disk. Tenderness or pain on movement is noted and can be indicative of inflammatory changes in the retrodiscal tissues, which are highly vascular and innervated. Clicking in the TMJ is often noticeable through auricular palpation but may be difficult to detect in palpation directly over the lateral pole of the condylar process, because the overlying tissues can muffle the click. Placement of the fingertips on the angles of the mandible helps identify even a minimal click, because very little soft tissue lies between the fingertips and the mandibular bone.
A maximum mandibular opening resulting in less than 35 mm of interincisal movement is considered restricted, because the average opening is greater than 50 mm.9,10 Such restricted movement on opening can be indicative of intracapsular changes in the joints. Similarly, any midline deviation on opening and/or closing is recorded. The maximum lateral movements of the patient can be measured (normal is about 12 mm) (Fig. 1-10).
Next, the masseter and temporal muscles, as well as other relevant postural muscles, are palpated for signs of tenderness (Fig. 1-11). Palpation is best accomplished bilaterally and simultaneously. This allows the patient to compare and report any differences between the left and right sides. Light pressure should be used (the amount of pressure one can tolerate when gently pushing on one’s closed eyelid without feeling discomfort is a good comparative measure), and if any difference is reported between the left and right sides, the patient is asked to classify the discomfort as mild, moderate, or severe. If there is evidence of significant asynchronous movement or TMJ dysfunction, a systematic sequence for comprehensive muscle palpation should be followed as described by Solberg9 and Krogh-Poulsen and Olsson.11 Each palpation site is given a numerical score based on the patient’s response. If neuromuscular or TMJ treatment is initiated, the examiner can then repalpate the same sites periodically to assess the response to treatment (Fig. 1-12).
Fig. 1-12 Palpation sites for assessing muscle tenderness. A, Temporomandibular joint capsule: lateral and dorsal. B, Masseter: deep and superficial. C, Temporal muscle: anterior and posterior. D, Vertex. E, Neck: nape and base. F, Sternocleidomastoid muscle: insertion, body, and origin. G, Medial pterygoid muscle. H, Posterior digastric muscle. I, Temporal tendon. J, Lateral pterygoid muscle.
(From Krogh-Poulsen WG, Olsson A: Occlusal disharmonies and dysfunction of the stomatognathic system. Dent Clin North Am 10:627, 1966.)
The patient is observed for tooth visibility during normal and exaggerated smiling. This can be critical in fixed prosthodontic treatment planning,12 especially for margin placement of certain metal-ceramic crowns. Some patients show only their maxillary teeth during smiling. More than 25% do not show the gingival third of the maxillary central incisors during an exaggerated smile13 (Fig. 1-13). The extent of the smile depends on the length and mobility of the upper lip and the length of the alveolar process. When the patient laughs, the jaws open slightly and a dark space is often visible between the maxillary and mandibular teeth (Fig. 1-14). This has been called the negative space.14 Missing teeth, diastemas, and fractured or poorly restored teeth disrupt the harmony of the negative space and often require correction.15
Fig. 1-13 Smile analysis is an important part of the examination, particularly when anterior crowns or fixed dental prostheses are being considered. A, Some individuals show considerable gingival tissue during an exaggerated smile. B, Others may not show the gingival margins of even the central incisors.
The intraoral examination can reveal considerable information concerning the condition of the soft tissues, teeth, and supporting structures. The tongue, floor of the mouth, vestibule, cheeks, and hard and soft palates are examined, and any abnormalities are noted. This information can be evaluated properly during treatment planning only if objective indices, rather than vague assessments, are used.
A periodontal examination16 should provide information regarding the status of bacterial accumulation, the response of the host tissues, and the degree of reversible and irreversible damage. Because long-term periodontal health is essential for successful fixed prosthodontics (see Chapter 5), existing periodontal disease must be corrected before any definitive prosthodontic treatment is undertaken.
The gingiva should be lightly dried before examination so that moisture does not obscure subtle changes or detail. Color, texture, size, contour, consistency, and position are noted and recorded. The gingiva is then carefully palpated to express any exudate or pus that may be present in the sulcular area.
Healthy gingiva (Fig. 1-15A) is pink, stippled, and firmly bound to the underlying connective tissue. The free margin of the gingiva is knife-edged, and sharply pointed papillae fill the interproximal spaces. Any deviation from these findings should be noted. With the development of chronic marginal gingivitis (Fig. 1-15B), the gingiva becomes enlarged and bulbous, loss of stippling occurs, the margins and papillae are blunted, and bleeding and exudate are observed.
Fig. 1-15 A, Healthy gingiva: pink, knife-edged, and firmly attached. B, Gingivitis: Plaque and calculus have caused marginal inflammation, with changes in color, contour, and consistency of the free gingival margin. Inflammation extends into the keratinized attached gingiva.
The width of the band of attached keratinized gingiva around each tooth may be assessed by measuring the surface band of keratinized tissue in an apicocoronal dimension with a periodontal probe and subtracting the measurement of the sulcus depth. Another method of obtaining this measurement by visual examination is to gently depress the marginal gingiva with the side of a periodontal probe or explorer. At the mucogingival junction (MGJ), the effect of the instrument is seen to end abruptly, indicating the transition from tightly bound gingiva to more flexible mucosa. Injecting anesthetic solution into the nonkeratinized mucosa close to the MGJ to make the mucosa balloon slightly is a third method of visualizing the MGJ. However, this is done only if the other methods do not provide the desired information.
The periodontal probe (Fig. 1-16A) is one of the most reliable and useful diagnostic tools available for examining the periodontium. It provides a measurement (in millimeters) of the depth of periodontal pockets and healthy gingival sulci on all surfaces of each tooth. In this examination, the probe is inserted essentially parallel to the tooth and is “walked” circumferentially through the sulcus in firm but gentle steps; the examiner determines the measurement when the probe is in contact with the apical portion of the sulcus (Fig. 1-16B). Thus, any sudden change in the attachment level can be detected. The probe may also be angled slightly (5 to 10 degrees) in the interproximal areas to reveal the topography of an existing lesion. Probing depths (usually six per tooth) are recorded on a periodontal chart (Fig. 1-17), which also contains other data pertinent to the periodontal examination (e.g., tooth mobility or malposition, open or deficient contact areas, inconsistent marginal ridge heights, missing or impacted teeth, areas of inadequate attached keratinized gingiva, gingival recession, furcation involvements, and malpositioned frenum attachments).
Fig. 1-16 A, Three types of sulcus/pocket-measuring probes. B, Correct position of a periodontal probe in the interproximal sulcular area, parallel to the root surface and in a vertical direction as far interproximally as possible. C and D, Graduated furcation probe.
(A and C, From Boyd: Dental Instruments, 2nd ed. St. Louis, WB Saunders, 2005.)
Fig. 1-17 Chart for recording pocket depths. The parallel lines are approximately 2 mm apart. The notations involved in using the chart are as follows: 1, Block out any missing teeth. 2, Draw a red X through the crown of any tooth that is to be extracted. 3, Record the gingival level with a continuous blue line. 4, Record pocket depths with a red line interrupted at the proximal surfaces of each tooth. 5, Shade the pocket form on each tooth with a red pencil (between the red and blue lines). 6, Indicate bifurcation or trifurcation involvements with a small red X at the involved area. 7, Record open contacts with vertical parallel lines (||) through the area. 8, Record improper contacts with a wavy red line through the area. 9, Record gingival overhang(s) with a red spur (^) through the area. 10, Outline cavities and faulty restorations of periodontal significance in red. 11, Indicate rotated teeth by outlining in blue to show their actual position.
(Modified from Goldman HM, Cohen DW: Periodontal Therapy, 5th ed. St. Louis, Mosby, 1973.)
Documenting the level of attachment helps the clinician determine the amount of periodontal destruction that has occurred and is essential in rendering a diagnosis of periodontitis (loss of connective tissue attachment).17,18 This measurement also provides the clinician with more detailed and accurate information regarding the prognosis of an individual tooth. The clinical attachment level is determined by measuring the distance between the apical extent of the probing depth and a fixed reference point on the tooth, most commonly either the apical extent of a restoration and/or the cementoenamel junction (CEJ). This measurement can be documented on modified periodontal charts (Fig. 1-18) and incorporated with the standard periodontal documentation (see Fig. 1-17) to complete the clinical periodontal examination. When the free margin of the gingiva is located on the clinical crown and the level of the epithelial attachment is at the CEJ, there is no loss of attachment, and recession is noted as a negative number. When the level of the epithelial attachment is on root structure and the free margin of the gingiva is at the CEJ, the attachment loss equals the probing depth, and the recession is 0. In a situation in which there is increased periodontal destruction and recession, the loss of attachment measurement equals the probing depth plus the measurement of recession19 (see Fig. 1-18B and C). Clinical attachment loss is a measure of periodontal destruction at a site, rather than current disease activity, and it may be considered the diagnostic “gold standard” for periodontitis.20 It should be documented in the initial periodontal examination.21 It is an important consideration in the devel opment of the overall diagnosis, treatment plan, and prognosis of the dentition and can be an effective research tool.
Fig. 1-18 A, Modified periodontal chart. B, Maxillary right sextant of modified periodontal chart with areas to record probing depths (PD), recession, and attachment loss (AL). C, Maxillary left sextant of modified periodontal chart exhibiting clinical documentation.
(Courtesy of the University of Detroit Mercy School of Dentistry, Department of Periodontology and Dental Hygiene, Detroit, Michigan.)
An accurate charting of the state of the dentition reveals important information about the condition of the teeth and facilitates treatment planning. Adequate charting (Fig. 1-19), in addition to all periodontal information, must show the presence or absence of teeth, dental caries, restorations, wear faceting and abrasions, fractures, malformations, and erosions. Missing teeth often have an effect on the position of adjacent teeth (see also the section on arch integrity in Chapter 3). Similarly, the presence of dental caries on one interproximal surface should alert the examiner to carefully inspect the adjacent proximal wall, even if caries is not apparent radiographically. The degree and extent of caries development over time can have a considerable effect on the eventual outcome of fixed prosthodontic treatment. The condition and type of the existing restorations are noted (e.g., amalgam, cast gold, composite resin, all-ceramic). Open contacts and areas where food impaction occurs must also be identified. The presence of wear facets is indicative of sliding contact sustained over time and thus may indicate parafunctional activity (see Chapter 4). Wear facets are often easier to see on diagnostic casts, however (see Chapter 2); during the clinical examination, the location of any observed facet is recorded. Fracture lines in teeth may necessitate fixed prosthodontic intervention, although minor hairline cracks in walls that are not subject to excessive loading can often go untreated and simply be observed at recall appointments (see Chapter 32). The location of fractures should be indicated on the chart, as should any other abnormalities.
Fig. 1-19 A, An appropriate charting system designates the location, type, and extent of existing restorations and the presence of any disease condition, all of which become part of the permanent patient record. B, Radiographic findings obtained from a full-mouth series are correlated with the clinical findings and noted in the record. C to E, Charting is performed to provide a quick reference to conditions in the mouth. The following may be useful: (1) Amalgam restorations (C) are depicted by an outline drawing blocked in solidly to show the size, shape, and location of the restoration. (2) Tooth-colored restorations (D) are depicted by an outline drawing of the size, shape, and location of the restoration. (3) Gold restorations (E) are depicted by an outline drawing inscribed with diagonal lines to show the size, shape, and location of the restoration. (4) Missing teeth are denoted by a large X on the facial, lingual, and occlusal diagrams of each tooth that is not visible clinically or on radiographs. (5) Caries is recorded by circling the tooth number located at the apex of the involved tooth and noting the presence and location of the cavity in the description column corresponding to the tooth number on the right. (6) Defective restorations are recorded by circling the tooth number and noting the defect in the description column.
(Modified from Roberson T, et al: The Art and Science of Operative Dentistry, 4th ed. St. Louis, Mosby, 2002.)
The initial clinical examination starts with the clinician’s asking the patient to make a few simple opening and closing movements while the clinician carefully observes the opening and closing strokes. The objective is to determine to what extent the patient’s occlusion differs from the ideal (see Chapter 4) and how well the patient has adapted to this difference. Special attention is given to initial contact, tooth alignment, eccentric contacts, and jaw maneuverability.
The relationship of teeth in both centric relation (see Chapter 4) and the maximum intercuspation should be assessed. If all teeth come together simultaneously at the end of terminal hinge closure, the centric relation (CR) position of the patient is said to coincide with the maximum intercuspation (MI) (see Chapters 2 and 4). The patient is guided into a terminal hinge closure to detect where initial tooth contact occurs (see the sections on bimanual manipulation and terminal hinge closure in Chapters 2 and 4). The clinician should ask the patient to “close feather-light” until any of the teeth touch and to have the patient help identify where that initial contact occurs by asking him or her to point at the location. If initial contact occurs between two posterior teeth (usually molars), the subsequent movement from the initial contact to the MI position is carefully observed and its direction noted. This is referred to as a slide from CR to MI. The presence, direction, and estimated magnitude of the slide are recorded, and the teeth on which initial contact occurs are identified. Any such discrepancy between CR and MI should be evaluated in the context of other signs and symptoms that may be present (e.g., elevated muscle tone previously observed during the extraoral examination, mobility on the teeth where initial contact occurs, wear facets on the teeth involved in the slide).
The teeth are evaluated for crowding, rotation, supra-eruption, spacing, malocclusion, and vertical and horizontal overlap (Fig. 1-20). Teeth adjacent to edentulous spaces often have shifted position slightly. Small amounts of tooth movement can significantly affect fixed prosthodontic treatment. Tipped teeth affect tooth preparation design or, in severe cases, may result in a need for minor tooth movement before restorative treatment. Supra-erupted teeth are often overlooked clinically but frequently complicate fixed dental prosthesis design and fabrication.
The relative relationship of adjacent teeth to teeth that require fixed prosthodontic treatment is important. A tooth may have drifted into the space previously occupied by the tooth in need of treatment because a large filling was previously lost. Such changes in alignment can seriously complicate or preclude fabrication of a cast restoration for the damaged tooth and may even necessitate its extraction.
The degree of vertical and horizontal overlap of the teeth is noted. When asked, most patients are capable of making an unguided protrusive movement. During this movement, the degree of posterior disclusion that results from the overlaps of the anterior teeth is observed.
The patient is then guided into lateral excursive movements, and the presence or absence of contacts on the nonworking side and then the working side is noted. Such tooth contact in eccentric movements can be verified with a thin Mylar strip (shim stock). Any posterior cusps that hold the shim stock are evident (Fig. 1-21). Teeth that are subject to excessive loading may develop varying degrees of mobility. Tooth movement (fremitus) should be identified by palpation (Fig. 1-22). If a heavy contact is suspected, a finger placed against the buccal or labial surface while the patient lightly taps the teeth together helps locate fremitus in MI.
The ease with which the patient moves the jaw and the way it can be guided through hinge closure and excursive movements should be assessed, because these factors are a good guide to neuromuscular and masticatory function. If the patient has developed a pattern of protective reflexes, manipulating the jaw is difficult. The patient’s restricted maneuverability is recorded.
Radiographs provide essential information to supplement the clinical examination. Detailed knowledge of the extent of bone support and the root structure of each standing tooth is essential for establishing a comprehensive fixed prosthodontic treatment plan. Although radiation exposure guidelines recommend limiting the number of radiographs to only those that will result in potential changes in treatment decisions, a full periapical series (Fig. 1-23) is normally required for new patients so that a comprehensive fixed prosthodontic treatment plan can be developed. Patient exposure can be minimized by using a technique that provides the most information with a minimal need for repeat films and by using appropriate protection. The use of digital radiography can further help reduce radiation exposure.
Panoramic films (Fig. 1-24) provide useful information about the presence or absence of teeth. They are especially helpful in assessing third molars and impactions, evaluating the bone before implant placement (see Chapter 13), and screening edentulous arches for buried root tips. However, they do not provide a sufficiently detailed view for assessing bone support, root structure, caries, or periapical disease.
Fig. 1-24 A panoramic film cannot be substituted for a full-mouth series because the image is distorted. Nevertheless, it is very useful for assessing unerupted teeth, screening edentulous areas for buried root tips, and evaluating the bone before implant placement.
Special radiographs may be needed for the assessment of TMJ disorders and a wide variety of pathologies ranging from bone and mineral disorders to metabolic disorders, genetic abnormalities, and soft tissue calcifications such as carotid artery calcification.21 For assessment of the TMJs, a transcranial exposure (Fig. 1-25), with the help of a positioning device, reveals the lateral third of the mandibular condyle and can be used to detect structural and positional changes. However, interpretation may be difficult,22 and more information may be obtained from other images23 (Fig. 1-26).