Interpreting dental radiographs

Quintessentials of Dental Practice – Imaging – Interpreting Dental Radiographs Authors: Keith Horner John Rout Vivian E Rushton Editors: Nairn H F Wilson Keith Horner Quintessence Publishing Co Ltd London, Berlin, Chicago, Copenhagen, Paris, Milan, Barcelona, Istanbul, São Paulo, Tokyo, New Delhi, Moscow, Prague, Warsaw www.ajlobby.com British Library Cataloguing in Publication Data Horner, K (Keith), 1958 Interpreting dental radiographs - (The quintessentials of dental practice) Teeth - Radiography I Title II Rout, P G J (Peter Graham John) III Rushton, V E IV Wilson, Nairn H F 617.6'07572 ISBN 1850973164 Copyright © 2002 Quintessence Publishing Co Ltd., London All rights reserved This book or any part thereof may not be reproduced, stored in a retrieval system, or transmitted in any form or by any means, electronic, mechanical, photocopying, or otherwise, without the written permission of the publisher ISBN 1-85097-316-4 www.ajlobby.com Table of Contents Tittle Page Copyright Page Foreword Preface Chapter Basic Principles Aim Introduction What Makes the Image? The Nature of the Radiation X-ray energy X-ray intensity The Nature of the Object Atomic number Physical density Thickness and shape The Characteristics of the Image Receptor How “Accurate” is a Radiographic Image? Magnification Image Sharpness Spatial Perspective Temporal Perspective How Should We Interpret the Radiographic Image? Using the Best Viewing Conditions Systematic Examination of Radiographs Summary Further Reading Chapter Normal Anatomy Aim Introduction Teeth and the Periodontium The Tooth www.ajlobby.com Pulp anatomy Developing Teeth Alveolar Bone The Maxilla Anterior region Canine/premolar region Molar region Third molar region The Mandible Anterior region Premolar region Molar region Sockets and Healing Further Reading Chapter Dental Caries Aim Introduction Radiographic technique Types of caries Proximal caries “Pre-radiological” Enamel Lesion The Lesion at the Amelodentinal Junction Dentine Lesion Lesions at the Pulp Factors Affecting Radiological Interpretation of Proximal Caries Monitoring Proximal Caries Occlusal caries Factors Affecting Radiological Interpretation of Occlusal Caries Buccal/lingual caries Root Surface (Cemental) Caries Secondary (recurrent) caries Diagnostic validity of radiology in caries diagnosis Further Reading Chapter Radiology of the Periodontal Tissues Aim Introduction www.ajlobby.com Periodontal Disease Classification Choice of Radiographs Interpreting Periodontal Bone on Radiographs Bone Loss Furcation bone loss Vertical Bony Defects Interproximal crater Infrabony defect Aggravating Factors Calculus Poorly contoured restorations Tilted teeth Caries Other Associated Features Evidence of occlusal trauma Bone sclerosis Maxillary sinus changes Root resorption Hypercementosis Aggressive Periodontitis Lateral Periodontal Abscess Periodontal/Endodontic Lesion Further Reading Chapter Periapical and Bone Inflammation Aim Introduction Choice of Radiographs Classification of Inflammatory Lesions Periapical Inflammatory Disease Chronic Periapical Periodontitis Clinical features Radiological signs Acute Periapical Periodontitis Clinical features Radiological signs Lesions Associated with Inflammation External and internal resorption of teeth Clinical features www.ajlobby.com Radiological signs Clinical features Radiological signs Hypercementosis Radiological signs Pericoronitis Clinical features Radiological signs Osteomyelitis Clinical features Radiological signs Clinical features Radiological signs Clinical features Radiological signs Clinical features Radiological signs Clinical signs Radiological signs Further Reading Chapter Anomalies of Teeth Aim Introduction A Classification of Dental Anomalies Anomalies of Enamel: Localised or Generalised Turner’s Hypoplasia Clinical features Radiological signs Amelogenesis Imperfecta Clinical features Radiological signs Clinical features Radiological signs Anomalies of Dentine: Generalised Clinical features Radiological signs Clinical features Radiological signs www.ajlobby.com Anomalies of Enamel and Dentine Clinical features Radiological signs Altered Crown Morphology Clinical features Radiological signs Anomalies of the Pulp/Root Canals Pulp Stones/Pulp Sclerosis Altered Root Morphology Radiological signs Supernumerary Roots Radiological signs Dilacerated Root Radiological signs Shortened Roots Alteration in Tooth Size Radiological signs Radiological signs Altered Tooth Morphology Radiological signs Anomalies Affecting the Number of Teeth Clinical features Radiological signs Additional Teeth (Hyperdontia) Clinical features Radiological signs Further Reading Chapter Trauma to the Teeth and Jaws Aim Introduction Choice of Radiographs Trauma to the dentition Dentoalveolar Fractures Fractures of the Mandible Trauma to the Teeth and Supporting Tissues Luxation Tooth Fracture Fractures of the crown www.ajlobby.com Fractures of the root Sequelae of Tooth Trauma Fractures Involving Bone Dentoalveolar fractures Fracture of the maxillary tuberosity Fracture of the genial tubercles Fracture of the mandible Further Reading Chapter Assessment of Roots and Unerupted Teeth Aim Introduction Choice of Radiographs Mandibular Third Molars Radiographic Assessment of Mandibular Third Molars Type and angulation of the impaction The crown The roots Bone factors Other teeth Maxillary Canines Radiographic Assessment of Maxillary Canines Position Crown and root form Follicular size Condition of other teeth Retained Roots Further Reading Chapter Radiolucencies in the Jaws Aim Introduction Choice of Radiographs Assessing Radiolucencies in the Jaws The Site of the Lesion The Shape of the Lesion The Margin and Lumen of the Lesion The Presence/Absence of Expansion Multiplicity of Lesions www.ajlobby.com The Presence of a Periosteal Reaction The Effect of the Lesion on Other Structures Radiolucencies in the Jaws Radiological signs Radicular Cyst and Residual Cyst Clinical features Radiological signs Dentigerous Cyst Clinical features Radiological signs Lateral Periodontal Cyst Clinical features Radiological signs Keratocyst Clinical features Radiological signs Nasopalatine Cyst Clinical features Radiological signs Solitary Bone Cyst Clinical features Radiological signs Ameloblastoma Clinical features Radiological signs Metastatic Deposits Clinical features Radiological signs Surgical (Fibrous Healing) Defect Radiological signs Giant Cell Granuloma Clinical features Radiological signs Hyperparathyroidism Clinical features Radiological signs Further Reading Chapter 10 Mixed Density and Radiopaque Lesions 10 www.ajlobby.com small so the diagnosis seems most probably osteosclerosis Fig 10-8 Osteosclerosis, possibly containing a primary root fragment Fibro-Cemento-Osseous Lesions This refers to a group of conditions in which bone is replaced by fibrous tissue that, in turn, then undergoes mineralisation by cementum or bone Histologically, it can be difficult to distinguish bone from cementum and hence cementum and osseouscontaining conditions are considered together Their radiographic appearance depends on the relative amounts of fibrous and calcified tissues The group consists of: periapical cemental dysplasia florid cemento-osseous dysplasia cemento-ossifying fibroma benign cementoblastoma The last is very rare The first two are, in contrast, relatively frequent and important to the dentist As such we will concentrate solely upon these “cemento-osseous dysplasias” Clinical features Both periapical cemental dysplasia and florid cemento-osseous dysplasia are found mainly in middle-aged women, particularly Afrocaribbean and Asian women They are asymptomatic and so discovered as an incidental radiographic finding Several lesions develop especially around lower incisors and first molars roots, although any tooth may be involved The affected teeth maintain their vitality As the 177 condition is self-limiting, it requires monitoring rather than surgical intervention The “florid” form is characterised by larger multi-quadrant lesions Radiological features This depends on the stage of development Initially the fibrous tissue component predominates resulting in a periapical radiolucency with a well-defined margin (Fig 10-9) During this phase, it resembles a periapical inflammatory lesion (see Chapter 5) As the lesion matures, cementum or bone is deposited, so that it now appears as a mixed-density lesion These deposits of cementum are surrounded by a zone of radiolucency In the third or final stage when further mineralisation has taken place, the lesion becomes almost entirely radiopaque, except for a thin peripheral radiolucent capsular space (Fig 10-10) An example of the florid form is shown in Fig 10-11 Occasionally, solitary bone cysts (see Chapter 9) may develop in patients with florid cemento-osseous dysplasia Fig 10-9 Early and intermediate periapical cemental dysplasia There are periapical radiolucencies involving both lower central incisors and 32, along with a separate lesion on 33 Fig 10-10 Late-stage periapical cemental dysplasia There is a large 178 radiopaque mass with a thin radiolucent margin Note the radiopacity difference between this lesion and the complex odontome in Fig 10-4 Fig 10-11 Florid osseous dysplasia There are multiple radiopaque masses in the mandible Fibrous Dysplasia In this condition, normal cancellous bone is replaced by fibrous tissue that subsequently undergoes mineralisation to varying degrees The condition may affect one bone (monostotic) or there may be more than one bony lesion (polyostotic) and when associated with endocrine and skin pigmentation is known as the McCuneAlbright syndrome The bones commonly affected are the ribs, femur and tibia and the jaws Clinical features This is a condition that occurs during childhood as a bony swelling and which usually arrests around the time of puberty There is no gender predilection except in the McCune-Albright syndrome, which mainly affects females Jaw lesions tend to be solitary and unilateral and occur more commonly in the maxilla than mandible They are usually painless Radiological signs The lesion may be largely radiolucent, but more often is seen as a radiopacity Typically, the bone has an altered trabecular pattern, which is seen as a “ground glass” or “stippled” appearance Except in the radiolucent type the margins are usually indistinct so that the lesion tends to merge with the normal surrounding bone Large lesions will expand, rather than perforate the cortical plates, so that in the maxilla, for example, the antral floor may be raised but remain intact Fibrous dysplasia may displace the teeth or interfere with normal eruption Examples of the condition are shown in Figs 10-12a,b and 10-13 179 Fig 10-12 Periapical (a) and lower true occlusal (b) views of a mainly radiolucent fibrous dysplasia, in the lower-left premolar region It is well defined and contains evidence of mineralisation There is displacement of the tooth roots The occlusal radiograph (b) shows expansion and thinning of the buccal and lingual cortical plates, which remain intact Fig 10-13 Orange peel effect typically associated with fibrous dysplasia, in the left maxilla This manifestation is more likely to be seen as the lesion becomes denser with age The stippled appearance is more likely to be visible on intraoral radiographs than extra-oral films due to its better resolution Paget’s Disease of Bone This is a condition where the normal processes of bone turnover, bone resorption and deposition become uncoordinated It can affect several bones including the spine, long bones, skull and jaws However, it is important to recognise that a patient may have the disease without jaw involvement Clinical features Paget’s disease mainly affects the middle aged or elderly Sometimes the patient 180 will complain of bone pain and when skull foramina are compressed the patient may have neurological pain, deafness or blindness It may affect the maxilla or mandible and when it does so it causes bilateral expansion as it involves the whole jaw The clinical appearance is of an expanded alveolus (Fig 10-14) The teeth become separated as the jaw enlarges Alternatively, the patient may complain that they are unable to insert their dentures Fig 10-14 Clinical photograph of patient with Paget’s disease affecting the maxilla The alveolar bone is grossly expanded buccally Radiological signs The bone progresses through an osteolytic and osteoblastic phase, which usually occur simultaneously, but with the osteblastic phase being ultimately more dominant Thus, the radiographic appearance is that of an increased radiopacity of the jaws The bone tends to become more granular in appearance and the lamina dura is obscured or difficult to identify (Fig 10-15) Here the bony trabeculae, particularly in the posterior part of the body of the mandible, may show linear striations In addition, the teeth show hypercementosis (Fig 10-15) A more classical appearance is that of granular- looking bone containing scattered islands of dense or fluffylooking bone, particularly in the region of the tooth apices (Fig 10-16) 181 Fig 10-15 Paget’s disease of the mandible The teeth show hypercementosis and have lost lamina dura The trabecular pattern is abnormal, with a horizontal pattern Fig 10-16 Paget’s disease of the maxilla on an occlusal radiograph showing hypercementosis, expansion of the alveolus and patchy radiopacity Osteoma There is some confusion whether osteomas are benign tumours of bone or hamartomas In the head and neck region they are most commonly found in the frontal/ethmoidal sinus region Osteomas may be derived from cancellous bone, compact bone or contain both types Clinical features Osteomas tend to occur in middle age as a slowly enlarging, painless, bony hard swelling (Fig 10-17) Most remain small and many stop enlarging, although some 182 reach a significant size Osteomas may be pedunculated or sessile, which on palpation appear to be continuous with the surface of the bone Fig 10-17 Clinical photograph of an osteoma of the maxilla It had shown slow but continued growth, with displacement of the upper canine, which was now traumatising the mucosa of the mandible Radiological signs The appearance depends on the type of osteoma Those arising from compact bone are densely radiopaque and are well defined (Fig 10-18) Large osteomas may have a lobulated appearance Osteomas arising from the cancellous bone have a trabecular pattern (Fig 10-19) Fig 10-18 True lateral and periapical radiographs showing a compact osteoma 183 Fig 10-19 A large cancellous osteoma shown on an occlusal view of the anterior aspect of the mandible Osteomas usually appear as a single lesion, so when multiple osteomas are present, Gardner’s syndrome (familial adenomatous polyposis coli) should be considered Gardner’s syndrome is a hereditary condition characterised by multiple osteomas, multiple unerupted supernumerary and permanent teeth, fibromas and lipomas of the skin, epidermoid cyst and polyps of the colon that invariably undergo malignant change The osteomas develop during the second decade of life and precede the development of the colonic polyps Thus, the dentist may be the first to recognise the condition Fig 10-20 shows a case of Gardner’s syndrome identified by radiography Fig 10-20 Patient with Gardner’s syndrome, showing two osteomas in the right third molar/angle region of the mandible There is a supernumerary tooth overlying 42 184 Metastatic carcinoma Most metastatic malignancies are radiolucent (see Chapter 9) A few, typically prostate and sometimes breast carcinoma, may stimulate bone formation and appear as radiopaque lesions in the jaws Radiopacities in the Soft Tissues Salivary calculi (sialoliths) Salivary calculi are calcific deposits that form within the duct lumen of the salivary glands They are of variable size and density and occur most frequently in the submandibular duct where they form by successive increments of mineral upon a central nidus Clinical features A salivary stone can form at any age but they are most commonly seen in adults The typical symptoms are pain and swelling of the affected salivary gland at meal times, particularly with acidic foods Duct obstruction does not, however, always produce symptoms Radiological signs Submandibular calculi Submandibular duct calculi are best visualised on a lower true occlusal view A calculus can form anywhere along the course of the duct, but it is usually found in the anterior part Very small stones at the duct orifice may be difficult to visualise, particularly if superimposed upon the lingual aspect of the mandible Small calculi tend to be round in shape, but as a calculus enlarges it develops a fusiform, layered appearance (Fig 10-21) Fig 10-21 Lower true occlusal showing a submandibular calculus 185 Parotid calculi Sometimes calculi may come to light because they fortuitously appear on a periapical radiograph (Fig 10-22a) Confirmation of the diagnosis can be obtained by exposing a periapical film in the buccal sulcus, adjacent to the duct orifice (Fig 10-22b) Fig 10-22 Parotid duct calculus superimposed on the crown of the upper second molar (a) The calculus was shown free of superimposition by exposing a small film in the buccal sulcus (b) Antroliths and Rhinoliths Antroliths are found in the maxillary sinus and rhinoliths in the nose Both are deposits of mineral upon the surface of a nidus, such as a tooth root, degenerate or infected tissue, or congealed mucus Clinical features Antroliths rarely produce symptoms but occasionally may be associated with recurrent sinusitis Rhinoliths sometimes cause localised mucosal inflammation resulting in epistaxis (nose bleeds) Both conditions are usually discovered as an incidental radiographic finding Radiological signs An antrolith appears as an irregularly shaped radiopacity of variable density, usually at the floor of the maxillary antrum (Fig 10-23) Rhinoliths are similarly variable in appearance (Fig 10-24) 186 Fig 10-23 Antrolith There is an ovoid radiopacity at the floor of the maxillary antrum in the upper molar region The central area is radiolucent and probably represents the central nidus In this example, the appearance resembles a tooth root Fig 10-24 Rhinolith The dense fusiform radiopacity in the left nasal cavity has the appearance of an unerupted canine, but 23 is present and erupted The foreign material was found to be a piece of BluTack™ (soft pliable adhesive) which had been mischievously inserted years previously Gingival Inflammatory Hyperplasia Hyperplasic localised gingival swelling can arise from local irritation Normally such masses are not well shown on radiographs, as they largely consist of soft tissue Sometimes the hyperplastic tissue undergoes sufficient mineralisation to be visible on a radiograph (Fig 10-25) 187 Fig 10-25 Dystrophic mineralisation of a gingival polyp The polyp is large, as shown by the faint milky appearance within which there is a large deposit of mineral and several smaller pieces Foreign Bodies Foreign bodies may be implanted into the soft tissues or bone These may be found as an incidental radiographic finding or as a result of a traumatic episode Dental materials One of the commonest foreign bodies found on radiographs of the mouth is dental amalgam This may occur when an extraction and filling are done on the same visit, or when apical surgery is carried out Amalgam is recognised by its radiopacity (Fig 10-26) Excess amalgam may also be left behind during apical surgery (Fig 10-27) Other materials can be seen, including socket dressings (Fig 10-28) and root filling materials (Fig 10-29) 188 Fig 10-26 Amalgam fragments in the lower-left wisdom tooth socket (top) A further radiograph (bottom) taken after surgical curettage shows that a few fragments still remain Fig 10-27 Large fragment of amalgam left after clumsy apicectomy Fig 10-28 Radiopaque dressing left in 17 socket 189 Fig 10-29 Excess root filling cement injected in to the maxillary antrum through the apex of the upper premolar Accidental implantation Material of various sorts may be implanted in to the soft tissues at the time of a road traffic accident or other trauma Such examples are shown in Figs 10-30 and 10-31 Relative radiopacity gives a clue to the nature of the material, but it is important to remember that some materials (e.g some types of glass, wood) will have a radiopacity similar to the soft tissues that surround them Fig 10-30 Glass fragments overlying the apex of the upper right canine apex The patient was unaware of their presence and this came to light when a periapical radiograph was taken to assess a painful maxillary canine The dense object overlying the upper right central incisor is a gold nose stud Fig 10-31 Air gun pellet superimposed over the upper right lateral incisor 103 190 Further Reading Smith B, Eveson J Paget’s disease of bone with particular reference to dentistry J Oral Pathol 1981;10:233 Soames J V, Southam J C Oral Pathology 2nd ed Oxford: Oxford University Press, 1993 Whaites E Differential Diagnosis of Lesions of Variable Radiopacity in the Jaws In: Whaites E Essentials of Dental Radiography and Radiology 3rd ed Edinburgh: Churchill Livingstone, 2002: 317–334 White SC, Pharoah MJ Soft tissue calcification In: White SC, Pharoah MJ (Eds.) Oral Radiology Principles and Interpretation 4th ed St Louis: Mosby, 2000 Wood NK (Review) Diagnosis, Oral Medicine, Radiology, and Treatment Planning 4th ed St Louis: Mosby, 1999 Wood NK, Goaz PW Differential Diagnosis of Oral and Maxillofacial Lesions 5th ed St Louis: Mosby, 1997: 415–518 191 ... included in dental x-rays – an outcome which can only enhance diagnostic acumen and patient care Interpreting Dental Radiographs is an excellent addition to the Quintessentials for General Dental. .. British Library Cataloguing in Publication Data Horner, K (Keith), 1958 Interpreting dental radiographs - (The quintessentials of dental practice) Teeth - Radiography I Title II Rout, P G J (Peter... Hyperplasia Foreign Bodies Dental materials Accidental implantation Further Reading 12 Foreword What proportion of procedures in general dental practice includes the interpretation of radiographs? All