Teeth 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 greatest attenuation of X-ray photons.
RADIOGRAPHIC APPEARANCE OF DENTIN 75% mineral content less radiopaque than enamel. Radiopacity similar to bone. ENANELODENTINAL JUNCTION appears as a distinct interface 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.
CERVICAL BURNUOUTRadiographs sometimes show diffuse radiolucent areas with ill defined borders present on the mesial or distal aspects of the teeth in the cervical region.These appear between the edge of the enamel cap and the crest of the alveolar ridge. This phenomenon is known as “ 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.
It is composed of soft tissues so it appears radioluscent.Pulp chambers and root canals extend from the interiors of the chamber till the root apices.Root canal extends till the apex it is seen radiographically also as apical foramen.In some cases it may exit on the side of the canal.Lateral canals may end at the apex as a discernible foramen or may exit at the side of the root.
The pulp canals of a developing tooth root diverge and walls of the root taper to a knife edge.A radiolucent area is seen surrounding it in the trabecular bone.It is surrounded by the hyperostotic bone. IT IS THE DENTAL PAPILLA WITH ITS BONY CRYPT.Its radiographic evaluation helps in determining the stage of maturation of the developing tooth.
RADIOGRAPHIC FEATURES OF LAMINA DURAIt is a thin radiopaque layer of dense bone surrounding the tooth socket. Its radiographic appearance is due to attenuation of the X-ray beam as it passes tangentially through the thickness of the bone. It is thicker than the surrounding trabecular bone and thickness increases with increase in amount of occlusal stress.
RADIOGRAPHIC FEATURES OF ALVEOLAR CREST It is the radiopaque gingival margin of the alveolar process which surrounds the teeth. It is considered normal if it is 1.5mm or less from the CEJ. It shows apical recession with the age or periodontal disease.
RADIOGRAPHIC FEATURES OF THE PERIODONTAL LIGAMENT SPACEIt is composed of collagen so appears as a radiolucent space between the root and lamina dura.It is thinner in the middle of the root and slightly wider near the alveolar crest and the apex suggesting that the fulcrum of the physiologic movements is in the region where PDL is thinnest.
RADIOGRAPHIC FEATURES OF THE CANCELLOUS BONEAlso called as the trabecular bone or the spongiosa.Lies between the cortical plates in both the jaws.It is composed of thin radiopaque plates and rods surrounding many small radioluscent pockets of marrow.In posterior maxilla it is similar to anteruor maxilla but marrow spaces are larger.
Also called as median suture.In IOPA it appears as a thin radioluscent line in the midline between the two portions of premaxilla.It extends from the alveolar crest between the central inscisors superiorly through the anterior nasal spine and continues posteriorly between the maxillary palatine process to the posterior aspect of the hard palate.
Mostly seen on IOPA of maxillary central inscisors.Located in midline1.5-2cm above the alveolar crest.It is radiopaque and usually V-shaped.
The nasal cavity shows the hazy shadow of the inferior nasal conchae extending from the right and left lateral walls
Also called as NASOPALATINE orANTERIOR PALATINE FORAMEN.It is the oral terminatus of the nasopalatine canal.It transmits the nasopalatine vessels and nerves.Lies in the midline of palate behind the central incisors at the junction of the median palatine and incisive sutures.Radiographic image variability is due to1.different angles of the X-ray beam.2.Variability in its anatomic size.
IT IS FREQUENTLY THE POTENTIAL SITE OF CYST FORMATION.
Radiographic features of superior foramina of the nasopalatine canalThe nasopalatine canal originates at two foramina in floor of the nasal cavity.Radiographically it can be recognized as two radioluscent areas above the apices of the central incisors in floor of the nasal cavity near its anterior border and both the sides of the septum.
Also called as INCISIVE FOSSA.Appears as depression in the maxilla near the apex of the lateral incisor .Appears diffusely radioluscent in the IOPA.
The soft tissue of the nose is frequently seen in the projections of the maxillary central and lateral incisors ,superimposed over the roots of these teeth.Image appears uniformly opaque with a sharp border.
The nasal and maxillary bones form the nasolacrimal canal.It runs from the medial aspect of the anteroinferior border of the orbit inferiorly,to drain under the inferior concha into the nasal cavity.
MAXILLARY SINUS is the air containing cavity lined by mucous membrane.DEVELOPMENT BY-invagination of the mucous membrane from the nasal cavity.Appears as the three sided pyramid . Base -formed by mesial wall adjacent to nasal cavity. Apex –extending laterally into the zygomatic process of maxilla.
On the IOPA maxillary sinus appears as a thin ,delicate , tenuous radiopaque line.It extends from the distal aspect of the canine to the posterior wall of the maxilla above the tuberosity.Around the age of puberty its floor coincides with the floor of the nasal cavity.
In older individuals the sinus may extend farther into the apical process,and in the posterior region of the maxilla its floor appears further below the level of the floor.
In response to the loss of function (associated with loss of posterior teeth) the sinus may expand farther into the alveolar bone , occasionally extending to the alveolar ridge.
Thin radioluscent lines of the uniform width are found within the image of the maxillary sinus. THESE ARE SHADOWS OF THE NEURO -VASCULAR CANALSTHAT ACCOMMODATE THE POSTERIOR SUPERIOR VESSELS AND NERVES.
The zygomatic process of the maxilla is an extension of the lateral maxillary surface that arises in the region of the apices of the first and the second molars and serves as the articulation for the zygomatic bone.Appears as U-shaped radiopaque line with rounded end of U projected in the apical region of the first and second molars.
An oblique line demarcating a region thatappears to be covered by a veil of slightradiopacity frequently traverses peri apicalradiographs of the premolar region.
The medial and lateral pterygoid plates lie immediately posterior to the tuberosity of maxilla.They cast a single radiopaque shadow without any evidence of trabeculation.
Extending inferiorly from the medial pterygoid plate, the hamular process may be seen which on close inspection show trabeculae.
The region of mandibular symphysis in infants demonstrate a radiolucent line through the midline of the jaw between the images of the forming deciduous central incisors.The suture usually fuses by the end of 1st year of life and is no longer radiographically apparent.
These are tiny bumps of bone that serve as attachment for the genioglossus and geniohyoid muscles.Present on lingual side.On IOPA appear as ring shaped radiopacity below the apices of mandibular incisors.
It is a hole or tiny opening located on the internal surface of mandible and surrounded by the genial tubercles.Raiographically appears as a radiolucent dot inferior to the apices of the mandibular incisors.
nutrient canals are tube like passage- ways through bone that contains nerves and blood vessels that supply the teeth.Radiographically seen as vertical radiolucent lines.More prominent in anterior mandible where bone is thin.
It is a linear prominence of cortical bone located on the external surface extendibg from the premolar region to the midline and slopes upward.Radiographically appears as a radiopaque band that extends from the premolar region to the incisor region.
Located above the mental ridge.On peri apical radiograph appears as a radiolucent area above the mental ridge.
Located on the external surface of the mandible as an opening in the region of the mandibular premolars. Mental nerves and blood vessels exit through it. Radiogarphically it appears as a small ovoid radiolucent area located below the apices of the premolars.
Linear prominence of bone located on the internal surface of mandible. Extends from the molar region downward and forward towards the lower border of mandibular symphysis. On IOPA appears as radiopaque band extending downward from molars.
Tube like passage extending from the mandibular foramen to the mental foramen and contains inf.alv. Nerves and blood vessels. Appears as a radiolucent band outlined by two radiopaque lines of cortical plate.
Linear prominence of bone located on internal surface of mandible extending downwards and forwards from ramus.It appears as a radiopaque band extending downwards from ramus.
Linear prominence of bone located on external surface of mandible extending downwards and is a continuation of anterior border of ramus. It appears as a radiopaque band extending downwards and forwards from ant. Border of mandible ends in 3rd molar region.
Depressed area of bone located on the internal surface of mandible. Submandibular salivary gland lies in this fossa. It appears as a radiolucent area in the molar region below the mylohyoid ridge.
It is a marked prominence of bone on the ant. Ramus of the mandible. Not seen on a mandibular IOPA but appears on a maxillary molars IOPA. It is seen as a triangular radiopacity superimposed over or inferior to maxillary tuberosity.
Occassionaly seen as a dense broad radiopaque band of bone.
Vary in their radiographic appearance.Depend primarily on their thickness, density and atomic number.A variety of restorative materials may be recognized on intra oral radiographs.