Radiographic Aids in Periodontal Disease PDF

Radiographic Aids in the Diagnosis of Periodontal Disease Dr.Banna alnufaiy  Radiographs are valuable for the diagnosis of periodontal disease, estimation of severity, determination of prognosis, and evaluation of treatment outcome. Radiographs are an adjunct to the clinical examination...

Radiographic Aids in the Diagnosis of Periodontal Disease Dr.Banna alnufaiy  Radiographs are valuable for the diagnosis of periodontal disease, estimation of severity, determination of prognosis, and evaluation of treatment outcome. Radiographs are an adjunct to the clinical examination, not a substitute for it. Radiographs demonstrate changes in calcified tissue; they do not reveal current cellular activity but rather reflect the effects of past cellular experience on the bone and roots.  Normal Interdental Bone The interdental bone normally is outlined by a thin, radiopaque line adjacent to the periodontal ligament (PDL) and at the alveolar crest, referred to as the lamina dura. Because the lamina dura represents the cortical bone lining the tooth socket, the shape and position of the root and changes in the angulation of the x-ray beam produce considerable variations in its appearance.  Normal Interdental Bone The width and shape of the interdental bone and the angle of the crest normally vary according to the convexity of the proximal tooth surfaces and the level of the cementoenamel junction (CEJ) of the approximating teeth. The faciolingual diameter of the bone is related to the width of the proximal root surface. The angulation of the crest of the interdental septum is generally parallel to a line between the CEJs of the approximating teeth. When there is a difference in the level of the CEJs, the crest of the interdental bone appears angulated rather than horizontal.  Radiographic Techniques The bone level, pattern of bone destruction, and PDL space width, as well as the radiodensity, trabecular pattern, and marginal contour of the interdental bone, vary by modifying exposure and development time, type of film, and x-ray angulation Periapical Bitewing Prichard (1972) established the following four criteria to determine adequate angulation of periapical radiographs: 1) The radiograph should show the tips of molar cusps with little or none of the occlusal surface showing. 2) Enamel caps and pulp chambers should be distinct. 3) Interproximal spaces should be open. 4) Proximal contacts should not overlap unless teeth are out of line anatomically.  For periapical radiographs, the long-cone paralleling technique most accurately projects the alveolar bone level. The bisection-of-the-angle technique elongates the projected image making the bone margin appear closer to the crown; the level of the facial bone is distorted more than that of the lingual. Inappropriate horizontal angulation results in tooth overlap, changes the shape of the interdental bone image, alters the radiographic width of the PDL space and the appearance of the lamina dura, and may distort the extent of furcation involvement.  Periapical radiographs frequently do not reveal the correct relationship between the alveolar bone and the CEJ This is particularly true in cases in which a shallow palate or floor of the mouth does not allow ideal placement of the periapical film. Bitewing projections offer an alternative method that better images periodontal bone levels. For bitewing radiographs, the film is placed behind the crowns of the upper and lower teeth parallel to the long axis of the teeth. The x-ray beam is directed through the contact areas of the teeth and perpendicular to the film. Thus the projection geometry of the bitewing films allows the evaluation of the relationship between the interproximal alveolar crest and the CEJ without distortion  If the periodontal bone loss is severe and the bone level cannot be visualized on regular bitewing radiographs, films can be placed vertically to cover a larger area of the jaws. More than two vertical bitewing films might be necessary to cover all of the interproximal spaces in the area of interest.  Bitewing radiography is the preferred imaging technique to depict periodontal bone levels in the posterior dentition. Bone Destruction in Periodontal Disease  Early destructive changes of bone that do not remove sufficient mineralized tissue cannot be captured on radiographs. Therefore slight radiographic changes of the periodontal tissues suggest that the disease has progressed beyond its earliest stages. The earliest signs of periodontal disease must be detected clinically. Bone Loss The radiographic image tends to underestimate the severity of bone loss. The difference between the alveolar crest height and the radiographic appearance ranges from 0 to 1.6 mm, mostly accounted for by x-ray angulation. Amount Radiographs are an indirect method for determining the amount of bone loss in periodontal disease; they show the amount of remaining bone rather than the amount lost. The amount of bone lost is estimated to be the difference between the physiologic bone level and the height of the remaining bone. Several investigators have analyzed the distance from the CEJ to the alveolar crest. Most studies, conducted in adolescents, suggest a distance of 2 mm to reflect normal periodontium; this distance may be greater in older patients. Distribution The distribution of bone loss is an important diagnostic sign. It points to the location of destructive local factors in different areas of the mouth and in relation to different surfaces of the same tooth. Pattern of Bone Destruction In periodontal disease the interdental bone undergoes changes that affect the lamina dura, crestal radiodensity, size and shape of the medullary spaces, and height and contour of the bone. The height of interdental bone may be reduced, with the crest perpendicular to the long axis of the adjacent teeth (horizontal bone loss), or angular or arcuate defects (angular, or vertical, bone loss) could form.  Radiographs do not indicate the internal morphology or depth of crater-like defects. Also, radiographs do not reveal the extent of involvement on the facial and lingual surfaces. Bone destruction of facial and lingual surfaces is masked by the dense root structure, and bone destruction on the mesial and distal root surfaces may be partially hidden by superimposed anatomy, such as a dense mylohyoid ridge In most cases, it can be assumed that bone loss seen interdentally continues in either the facial or lingual aspect, creating a troughlike lesion.  Dense cortical facial and lingual plates of interdental bone obscure destruction of the intervening cancellous bone. Thus a deep, craterlike defect between the facial and lingual plates might not be depicted on conventional radiographs. A reduction of only 0.5 to 1 mm in the thickness of the cortical plate is sufficient to permit radiographic visualization of the destruction of the inner cancellous trabeculae.  Periodontal bone loss should be differentiated from normal anatomy or anatomic variants that can resemble disease. For example, nutrient canals in the alveolar bone can appear as linear and circular radiolucent areas. These canals can be seen more frequently in the anterior mandible, although they can be present throughout the alveolar ridge.  It should be emphasized that radiographs can only assess the amount of periodontal bone that is present and deduce the extent of bone loss. However, it is sometimes necessary to determine whether the reduced bone level is the result of periodontal disease that is no longer destructive (usually after treatment and proper maintenance) or whether destructive periodontal disease is present. Differentiation between treated versus active periodontal disease can only be achieved clinically. Radiographically detectable changes in the normal cortical outline of the interdental bone are corroborating evidence of destructive periodontal disease. Radiographic Appearance of Periodontal Disease Periodontitis Radiographic changes in periodontitis follow the pathophysiology of periodontal tissue destruction and include the following: 1. Fuzziness and disruption of lamina dura crestal cortication continuity is the earliest radiographic change in periodontitis and results from bone resorption activated by extension of gingival inflammation into the periodontal bone ( Therefore it can be concluded that the presence of an intact crestal lamina dura may be an indicator of periodontal health, whereas its absence lacks diagnostic relevance ). 2. Continued periodontal bone loss and widening of the periodontal space results in a wedge-shaped radiolucency at the mesial or distal aspect of the crest. The apex of the area is pointed in the direction of the root. 3. Subsequently, the destructive process extends across the alveolar crest, thus reducing the height of the interdental bone. As increased osteoclastic activity results in increased bone resorption along the endosteal margins of the medullary spaces, the remaining interdental bone can appear partially eroded. 4. The height of the interdental septum is progressively reduced by the extension of inflammation and the resorption of bone. 5. Frequently a radiopaque horizontal line can be observed across the roots of a tooth. This opaque line demarcates the portion of the root where the labial or lingual bony plate has been partially or completely destroyed from the remaining bone- supported portion. Interdental Craters Interdental craters are seen as irregular areas of reduced density on the alveolar bone crests. Craters are generally not sharply demarcated but gradually blend with the rest of the bone. Conventional radiographs do not accurately depict the morphology or depth of interdental craters, which sometimes appear as vertical defects. Furcation Involvement Definitive diagnosis of furcation involvement is made by clinical examination, which includes careful probing with a specially designed probe (e.g., Nabers). Radiographs are helpful, but root superimposition, caused by anatomic variations or improper technique, can obscure radiographic representation of furcation involvement. As a general rule, bone loss is greater than it appears in the radiograph. To assist in the radiographic detection of furcation involvement, the following diagnostic criteria are suggested: 1. The slightest radiographic change in the furcation area should be investigated clinically, especially if there is bone loss on adjacent roots 2. Diminished radiodensity in the furcation area in which outlines of bony trabeculae are visible suggests furcation involvement 3. Whenever there is marked bone loss in relation to a single molar root, it may be assumed that furcation is also involved Periodontal Abscess The typical radiographic appearance of a periodontal abscess is a discrete area of radiolucency along the lateral aspect of the root, However, the radiographic picture is often not characteristic, This can be due to the following: 1. The stage of the lesion. In the early stages an acute periodontal abscess is extremely painful but presents no radiographic changes. 2. The extent of bone destruction and the morphologic changes of the bone. 3. The location of the abscess. Lesions in the soft tissue wall of a periodontal pocket are less likely to produce radiographic changes than those deep in the supporting tissues. Abscesses on the facial or lingual surface are obscured by the radiopacity of the root; interproximal lesions are more likely to be visualized radiographically. Clinical Probing Regenerative and resective flap designs and incisions require prior knowledge of the underlying osseous topography. Careful probing of these pocket areas after scaling and root planing often requires local anesthesia and definitive radiographic evaluation of the osseous lesions. Radiographs taken with periodontal probes, gutta- percha points, or other indicators (e.g., Hirschfeld pointers) placed into the anesthetized pocket show the true extent of the bone lesion.  Localized aggressive (formerly Localized Aggressive “localized juvenile”) periodontitis is characterized by the following: 1. Initially, there is bone loss in the Periodontitis maxillary and mandibular incisor or first molar areas, usually bilaterally, resulting in a vertical, arc like destructive pattern 2. As the disease progresses, loss of alveolar bone may become generalized but remains less pronounced in the premolar areas. Trauma From Occlusion Trauma from occlusion can produce radiographically detectable changes in: 1) The thickness of the lamina dura. 2) Morphology of the alveolar crest. 3) Width of the PDL space. 4) Density of the surrounding cancellous bone. Trauma From Occlusion The radiographic changes listed next are not pathognomonic for trauma from occlusion and must be interpreted in combination with clinical findings, particularly tooth mobility, presence of wear facets, pocket depth, and analysis of occlusal contacts and habits. The injury phase of trauma from occlusion produces a loss of the lamina dura that may be noted in apices, furcations, and marginal areas. This loss of lamina dura results in widening of the PDL space. The repair phase of trauma from occlusion results in an attempt to strengthen the periodontal structures to better support the increased loads. Radiographically, this is manifested by a widening of the PDL space, which may be generalized or localized Trauma From Occlusion More advanced traumatic lesions may result in deep angular bone loss, which, when combined with marginal inflammation, may lead to intrabony pocket formation. In terminal stages, these lesions extend around the root apex, producing a wide, radiolucent periapical image (cavernous lesions). Root resorption may also result from excessive forces on the periodontium, particularly those caused by orthodontic appliances. Although trauma from occlusion produces many areas of root resorption, these areas are usually of a magnitude insufficient to be detected radiographically. Digital Intraoral Radiography The digital records can be easily shared among dentists and other health care providers, enabling telediagnosis and facilitating transmission to third parties for reimbursement. Cone-beam computed tomography (CBCT) has revolutionized the field of oral and maxillofacial imaging. CBCT offers many advantages over conventional radiography, including accurate three- dimensional imaging of teeth and supporting structures. CBCT avoids the problems of geometric superimposition and unpredictable magnification and can provide valuable diagnostic information in periodontal evaluation. for assessment of periodontal bone loss, CBCT performed better than digital radiographs in the detection of early furcational defects, three-wall defects, fenestrations, and dehiscence