Recent Tooth Fracture Thin radiolucent line(s) extending through any portion of tooth. “Step defect.” Well-defined yet soft radiolucent band (where central x-ray beam cuts fracture line obliquely). For crown, transillumination and/or disclosing solutions often useful.
Tooth Displacement Concussion – no radiologic sign or pdl widening, most frequently apically. Subluxation – often tooth mobility with no radiologic sign or pdl widening. Luxation – Widened pdl (unless intrusive); minor alveolar fracture(s); step in dental occlusion.
Subluxation of mandibularanterior teeth followingtrauma.
Later changes followingluxation. Pulp necrosis – widened pulp due to absence of continued 2y dentin formation. Apical periodontal pathosis. External root resorption and possible ankylosis. Pulpal obliteration.
Resorption of root of maxillary centralincisor following trauma (thermalprint of RVG 32000 digital images).
Alveolar Fracture Sharply defined, uncorticated and occasionally jagged radiolucent line in alveolus. Fracture line(s) mostly horizontal. Segment of teeth may be displaced. Widened pdl spaces. Possible associated root fractures.
Mandibular Condyle Condylar head “sheared off” and telescoped inward on itself. Step defect. Overlap of trabecular pattern seen as band of increased opacity. Deviation of mandible to affected side. Rarely, condylar head maintains integrity.
Fracture of rightmandibular condyleand at left angle ofmandible.
RFracture of left mandibular condyle withmedial displacement of condylar head(Reverse Towne’s projection).
RFractures of mandibularsymphysis and left condyle.
Mandibular Body Radiographic visible line of cleavage if x- ray beam parallels fracture line. Line of cleavage may be indistinct if x-ray beam is not parallel to fracture line. Step defect. Contralateral condylar head frequently fractured.
Mandibular fracture (depressed) inleft canine/premolar region. Notefracture line and step in cortical outline.
Fracture at left mandibularangle shown on panoramicdental radiograph.
Zygomatic Arch Fractures Together with zygomatico-maxillary fractures, represent 25% of all facial fractures. Depression of zygomatic arch on submentovertex, Waters and PA views. Close proximity of coronoid process to zygomatic arch.
Depressed fractureof left zygomatic arch(2 different cases):(submentovertexviews).
Detail of depressedfracture of leftzygomatic arch:fractureleft side ofsubmentovertexprojection.
Zygomaticomaxillary Fractures Widening of zygomaticofrontal, zygomaticomaxillary and zygomaticotemporal suture lines. Step defects at junction of frontal and zygomatic bones, zygoma and maxilla, or zygoma and temporal bone (“tripod” fractures) . CT used for assessing on nasolacrimal canal, lateral rectus muscle of eye and posible intra- cranial hemorrhage .
RTripod fracture (depressed)of left malar complex (arrow).
RTripod fracture of left zygomaticcomplex (PA view).
Depressed fracture of left zygomatic arch(blue arrow) and blow-out fracture of leftorbital floor (yellow arrow) - Water’s view.
Depressed fracture of left zygomatic arch(blue arrow) and blow-out fracture (yellowarrow) of left orbital floor (Water’s view).
Blow-out Fracture Force transmitted to thin orbital floor, which generally fractures near infraorbital canal. Soft tissue swelling over orbital rim. Opacification of affected maxillary sinus. Displaced orbital floor (“trap door”). Polypoid density in roof of maxillary sinus through herniation of orbital contents. Cheek paresthesia if infraorbital canal involved.
Fracture of lateral wall plus blow-outfracture of left orbit (coronal CT). Note lackof continuity of orbital rim.
Blow-out fracture of left orbital floor inregion of infraorbital canal (coronal CT).
Blow-out fractureof left orbital floor:Water’sprojection.
Blow-out fracture of right orbital floorindicated solely by thickening of mucosalining superior antral wall (Water’s view).
Blowout fracture of right orbital floorindicated by thickening of roof of maxillarysinus (PA tomographic view) – see arrow.
Blow-out fracture of right orbit shows typical“trap door” sign. There is opacificationof the affected sinus (coronal tomograph).
Le Fort Type I Fracture above level of maxillary teeth involving alveolar process, palate and pterygoid plates. Clouding of maxillary sinus on one or both sides. Discontinuity of lateral maxillary sinus walls on plain radiographs. Sharp horizontal line of cleavage through maxilla, pterygoid plates and sphenoid. Canted maxilla relative to cranial base and mandibular teeth.
RLeFort I midfacial fracture with bilateral fracturesof the walls of the left and right maxillary sinuses.Both sinuses show opacification.
Le Fort Type II Pyramidal fracture across nasal bones and frontal processes of maxilla, extending laterally through lacrimal bones, inferior rim of orbit near zygomaticomaxillary suture, lateral walls of maxilla and pterygoid plates. Increased width of frontonasal suture. Radiolucent cleavage lines. Step defect in orbital rim. Sinus shadows obscurred by hemorrhage. Disruption in dental occlusion.
LLe Fort II midfacial fracture: fracture linesextend obliquely through nasofrontal sutures,through the medial and inferior aspects ofboth orbits and the lateral walls of both maxillarysinuses (PA view).
Le Fort II fracture (same case) shown withsurface-rendered 3-D reconstruction of axialCT slices.
Le Fort II fracture:note lack ofcontinuity inoutlines ofmaxillary sinuses(axial CT).
Le Fort Type III Craniofacial dysjunction with shearing of facial complex from cranial base. Involves nasofrontal, maxillofrontal and zygomaticofrontal sutures orbit, ethmoid sinus and sphenoid sinus floors. Widened frontonasal, maxillofrontal, zygomaticofrontal and zygomaticotemporal sutures. Radiolucent cleavage lines through frontal processes of maxilla, both pterygoid plates and one or both orbital floors. Sinus shadows obscurred by hemorrhage.
Le Fort III midface fractures: PA view showsfractures of lateral walls of both maxillary sinuseswith concomitant opacification of the sinuses.Glabella and right zygomaticofrontal sutures alsoevidence fracture lines.
Le Fort III fractures involvingnasoethmoidal region (lateral view).
Le Fort III fracture: lateral view demonstratesfracture lines in the nasoethmoidal region andanterior maxilla (both Le Fort III and Le Fort I).
Maxillofacial Fractures(1) CT is both the state-of-the-art and the current standard of care for maxillary fracture evaluation.(2) Panoramic radiography is the best modality for evaluation of the mandible following trauma.