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NORMAL RADIOGRAPHIC ANATOMICAL LANDMARKSDr. PINALI DAS1 st Year PGGuided by:DR SANAT KUMAR BHUYANDEPT OF ORAL MEDICINE AND RADIOLOGY
IntroductionTooth anatomy Supporting structuresAnatomical landmarks
Radiographic DensityRadiopacity light on filmRadiolucency - dark on film
Radiopaque vs. RadiolucentRadiopaque:refers to a light area on the filmStructures that are absorbers of x-rays block the x-rays from reaching the filmThe x-rays are attenuated (decreased in intensity) by absorbing structuresFewer photons reach the emulsionDense structures are strong absorbers
Radiopaque vs. RadiolucentRadiolucent:refers to a dark area on the filmStructures that are less dense are poor absorbers and allow more photons to reach the film emulsion
Tooth AnatomyTeeth are composed primarily of dentin, with an enamel cap over the coronal portion and a thin layer of cementum over the root surface.
Radiographic Appearance of Enamel ENAMEL appears more radio-opaque than other tissues.It is 90% mineral ;causes greater attenuation of X-ray photons. enamel
RADIOGRAPHIC APPEARANCE OF DENTIN
75% mineral content ;less radiopaque than enamel. Radiopacity similar to bone. DENTINO ENAMEL JUNCTION appears as a distinctinterface separating these two structures.
RADIOGRAPHIC APPEARANCE OF CEMENTUM
50%mineral content and it appears as a very thin layer on the root surface.It is usually not so apparent radiographically.
Radiographs sometimes show diffuse radiolucent areas with ill defined borders present on the mesial or distal aspects of the teeth in the cervical region.
These regions appear between the edge of the enamel cap and the crest of the alveolar ridge.
REASON FOR CERVICAL BURNOUT
Normal configuration of the affected teeth, results in decreased X-ray absorption in the areas in question.
Perception of these areas is due to contrast with the adjacent ,relatively radiopaque enamel and alveolar bone.
It should not be confused with root caries which has similar appearance.
Periodontal ligament space
Radiopaque structures common to maxillary and mandibular radiographs1.ENAMEL2.DENTIN3.CEMENTUM4.LAMINA DURA5.ALVEOLAR CREST6.TRABECULAE OF BONE
Radioluscent structures common to maxillary and mandibular radiographs1.PERIODONTAL LIGAMENT SPACE2.BONE MARROW SPACE3.PULP4.NUTRIENT CANALS
Radioopaque structues in maxillaryradiographs1.MAXILLARY TUBEROSITY2.CORONOID PROCESS OF MANDIBLE3.ZYGOMATIC PROCESS4.NASAL SEPTUM5.ANTERIOR NASAL SPINE6.SHADOW OF NOSE7.FLOOR OF NASAL CAVITY8.INFERIOR NASAL CONCHA9.WALL,FLOOR AND SEPTA OF MAXILLARY SINUS10.INVERTED Y OF ENNIS11.NASOLABIAL FOLD12.PTERYGOID PLATE AND HAMULAR PROCESS
Radioluscent structures in maxillary radiographs1.MAXILLARY SINUS2.INCISIVE FORAMEN3.MEDIAN PALATAL SUTURE4.NASAL FOSSA,NASAL CAVITY5.SUPERIOR FORAMINA OF NASOPALATINE CANAL6.LATERAL FOSSA7.NASOLACRIMAL CANAL
Radioopaque structues in mandibular radiographs1.BORDER OF MANDIBLE2.EXTERNAL OBLIQUE RIDGE3.GENIAL TUBERCLE4.MENTAL RIDGE5.MYLOHYOID RIDGE6.MANDIBULAR CANAL WALLS
Radioluscent structures in mandibular radiographs1.MANDIBULAR FORAMEN2.MANDIBULAR CANAL3.MENTAL FORAMEN,MENTAL FOSSA4.SYMPHYSIS5.LINGUAL FORAMEN6.NUTRIENT CANAL7.SUBMANDIBULAR FOSSA
Nasal septumInferior conchaNasal fossaNasal spineIncisive foramenNose Median palatine suture
Inferior conchafacial view
Nasal fossafacial view
Anterior nasal spine
Incisive foramenpalatal view
Median palatal suture
Soft tissue of the nose
Red arrows = lip line
Superior foramina of the nasopalatine canals (red arrows). These foramina lie in the floor of the nasal fossa. The nasopalatine canals travel downward to join in the incisive foramen.
The red arrows point to the soft tissue of the nose. The green arrows identify the lip line.
Floor of nasal fossaMaxillary sinusLateral fossaNose
a = floor of nasal fossab = maxillary sinusc = lateral fossa(a & b form inverted Y)
Lateral fossa. The radiolucency results from a depression above and posterior to the lateral incisor. To help rule out pathology, look for an intact lamina dura surrounding the adjacent teeth.facial view
Soft tissue of the nose
Red arrows point to nasolabial fold.
The maxillary sinus surrounds the root of the canine, which may be misinterpreted as pathology.
The black arrows indicate the floor of the nasal fossa. The maxillary sinus (red arrows) has pneumatized between the 2nd premolar and first molar
Zygomatic processSinus septumSinus recessMaxillary sinus
Maxillary Sinus. An air-filled cavity lined with mucous membrane. Communicates with nasal cavity through 3-6 mm opening below middle concha. Red arrows point to neurovascular canal containing superior alveolar vessels and nerves.
Malar (zygomatic) process. U or j-shaped radiopacity, often superimposed over the roots of the molars, especially when using the bisecting-angle technique. The red arrows define the lower border of the zygomatic bone.
Sinus septum. This septum is composed of folds of cortical bone that arise from the floor and walls of the maxillary sinus, extending several millimeters into the sinus. In rare cases, the septum completely divides the sinus into separate compartments.facial view
Sinus recess. Increased area of radiolucency caused by outpocketing (localized expansion) of sinus wall. If superimposed over roots, may mimic pathology.facial view
Maxillary sinusSinus recessZygoma Pterygoid plateHamularprocessCoronoid processMaxillary tuberosity
a = maxillary tuberosity* e = zygoma (dotted lines)b = coronoid process f = maxillary sinusc = hamular process g = sinus recessd = pterygoid plates
* image of impacted third molar superimposed
Maxillary Tuberosity. The rounded elevation located at the posterior aspect of both sides of the maxilla. Aids in the retention of dentures.facial view
Hamular process (black arrows) and pterygoid plates (purple arrows). The hamular process is an extension of the medial pterygoid plate of the sphenoid bone, positioned just posterior to the maxillary tuberosity. facial view
Zygomatic (malar) bone/process/arch. The zygomatic bone (white/black arrows) starts in the anterior aspect with the zygomatic process (blue arrow), which has a U-shape. The zygomatic bone extends posteriorly into the zygomatic arch (green arrow).
The zygomatic process (green arrows) is a prominent U-shaped radiopacity. Normally the zygomatic bone posterior to this is very dense and radiopaque. In this patient, however, the maxillary sinus has expanded into the zygomatic bone and makes the area more radiolucent (red arrows). The coronoid process (orange arrow), the pterygoid plates (blue arrows) and the maxillary tuberosity (pink arrows) are also identified.
symphysisRadiolucent line to the midline of the jaw between the central incisors .This suture usually fuses by the end of the first year of life after which it is no longer radiographically apparent.If radiolucency found- it is abnormal (# or cleft).
Genial tuberclesLocated on lingual surface , above the inferior border and in the midline.Bony protuberances , spine shaped divided into right , left, superior and inferior protuberances.Genioglossus muscle attached at the superior tubercles.Geniohyoid muscles attached at the inferior tubercles.
Mental fossaIt is a depression on the labial aspect of mandible extending laterally from the midline and above the mental ridge.Image may be similar to submandibular fossa and may be mistaken for periapical disease involving the incisors.
Mental fossa. This represents a depression on the labial aspect of the mandible overlying the roots of the incisors. The resulting radiolucency may be mistaken for pathology.
The orange arrows above identify nutrient canals. They are most often seen in older persons with thin bone, and in those with high blood pressure or advanced periodontitis.
Mental ridgeGenial tuberclesLingual foramenMental fossa
cb = mandibular canald = mental foramena = mylohyoid ridge (internal oblique)c = submandibular gland fossafacial viewlingual view
Mylohyoid (internal oblique) ridge. This radiopaque ridge is the attachment for the mylohyoid muscle. The ridge runs downward and forward from the third molar region to the area of the premolars.lingual view
Mandibular canal. (Inferior alveolar canal). Runs downward from the mandibular foramen to the mental foramen, passing close to the roots of the molars. More easily seen in the molar periapical.
Submandibular gland fossa. The depression below the mylohyoid ridge where the submandibular gland is located. More obvious in the mo