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Dr ARJUN SHENOYContents.Introduction.Surgical anatomyHistory.Epidemiology.Classification systems Clinical features and diagnosis Radiographic features Conclusion.References.
Mandibular fractures prominence of mandible
Surgical anatomyStrongest facial boneParabola shaped boneAngle of curvature is 110-140Mandible is the 2nd bone to ossifyEnergy of 44.6-74.4 kg/m required to fracture the mandible.
Weak areas of mandibleJunction between alveolar bone & basal mandibular bone.
Symphysis region - junction of two individual bones.
Parasymphyseal region - lateral to the mental prominence, incisive fossa and mental foramen.
Junction of the ramus and the body are fractured commonly.
Presence of impacted tooth, canine with long roots.
Age changes of mandible.Mental foramena. child near inferior border. old age near alveolar ridge.
Ramus angle. child & old obtuse
Blood supplySafe distance in mandible.Average thickness of Cortex in symphysis & parasymphisis region is 2.5 mm
Average thickness of Cortex in premolar & Body region is 3.5 mm
Distance between I.A. Canal & cortex At bicuspid - 4.0 mmMolar region - 5.9 mm
Anteriorly distanceBetween adjacentRoot apices is 3.7 mm
Posteriorly distance Between adjacent Root apices is 6.3 mm
Champys principles Forces of mastication produce tensional forces on upper border & forces of compression on lower border.
Champy put forward the lines where plates & screws have to be placed - ideal osteosynthesis lines
It corresponds to course of a line of tension at base of the alveolar process.
Only in symphysis region, 2 plates are placed to neutralize torsional forces.
Blood supply.Helps in the healing of fractured bone.
Endosteal blood supply via inferior dental artery & veins.
Peripheral blood supply - Periosteum
Nerve supply.Inferior alveolar nerve
Damage - angle & body #
Anesthesia or parasthesia of the nerve
Recovery / regeneration - 3 to 12 months
History.Egyptian Papyrus (1650 BC) Examination, diagnosis & treatment.
Hippocrates Approximation of # segments. Salerno, Italy (1180) Proper occlusion.
1492, the book Cyrurgia by Guglielmo Salicetti use of IMF.
John Barton - Barton Bandage
1860GILMERGILMERS WIRING & FULL ARCH BARS1900MAHEPLATING KIT SIMILAR TO MODERN SYSTEMS1920F. RISDONRISDONS WIRING1961LUHRDYNAMIC COMPRESSION PLATES1970BRONS & BOERINGLAG SCREWS1973MICHELETMINIPLATES FOR MAND OSTEOSYNTHESIS1978CHAMPYMINIPLATE OSTEOSYNTHESIS PRINCIPALS
CAR ACCIDENTS ASSAULTS BIKE ACCIDENTS Classification GeneralAnatomicalCompletenessMechanism of injuryNumber of fragmentsShape of fractureDirection & favorability of treatmentPresence or absence of teethAO classification.Kruger's Classification SIMPLE ( CLOSED)Linear fracture lines which do not communicate with the exterior
COMPOUND ( OPEN)The fracture is communicating intraorally or extraorally. COMMUNITED Shattering of bone into multiple pieces
COMPLEX COMPLICATEDThey is adjunct injury to the adjacent nerves or major blood vessels , joints.IMPACTEDOne fragment is firmly driven within the other fragment and clinical movement not appreciated GREENSTICKOnly one cortex broken. Common in childrenPATHOLOGICALSpontaneous fracture as a result of normal muscle contraction or trauma due to increased weakness of underlying bone .
Dingman & Natvig classification
Symphysis fracture Canine region fracture Body of the mandible fracture Angle fracture Ramus fractureCoronoid fracture Condylar fracture Dentoalveolar fracture
Direction & favorability of treatmentHorizontally Favourable Fracture line runsdownward & forward so upward displacement avoided
Horizontally Unfavourable Fracture line runs Down Wards and Back Wards soupward DisplacementUnrestricted
VERTICALLY FAVORABLE VERTICALLY UNFAVORABLEFRACTURE LINE RUNS FROM THE OUTER BUCCAL PLATE OBLIQUELY BACKWARDS AND LINGUALLY , MEDIAL MOVEMENT RESTRICTEDFRACTURE LINE RUNS FROM THE INNER LINGUAL PLATE OBLIQUELY BACKWARDS AND BUCCALLY , MEDIAL MOVEMENT UNRESTRICTED
Presence or absence of teeth
Kazanjian V.H. & Converse J.M.
CLASS 1 TEETH ON BOTH SIDES OF FRACTURE LINE
MONOMAXILLARY CLASS II TEETH ONLY ON ONE SIDE OF THE FRACTURE LINE INTERMAXILLARY FIXATION CLASS IIIEDENTULOUS PATIENT OPEN REDUCTION / PROSTHESIS AO ClassificationFNO. OF FRACTURE OR FRAGMENTS LLOCATION OF THE FRACTURE OSTATUS OF OCCLUSION S SOFT TISSUE INVOLVEMENT A ASSOCIATED FRACTURES
F: NO. OF FRACTURES
F0Incomplete fractures F1Single fractures F2Multiple fractures F3Comminuted fractures F4Fracture with bone defect L: Location of fractureL1Pre-canine L2Canine L3Post-canine L4Angle L5Supra-angular L6CondyleL7Coronoid L8Alveolar process O: Status of occlusionO 0 No malocclusion O 1 Malocclusion O 2 Edentulous mandible A: Associated fractureA 0 None A 1 Dentoalveolar fracture A 2 Nasal bone fracture A 3 Zygoma fracture A 4 Lefort I A 5 Lefort II A 6 Lefort IIIClinical examination.HistoryMechanism of injuryExtraoral / Intraoral
Clinical features. Extensive edema Tenderness. step deformity bone crepitus Facial asymmetry
Deviation of jaw Restriction of mouth opening
Extensive soft tissue and bony defect
Collapsed arch and Interfragmentary mobility Open bite due bilateral poster Gagging of occlusion Open bite and cross bite due to Unilateral gagging of occlusion Occlusal step with Unilateral cross bite
Mandibular fracture has to be differentiated from extensive Soft tissue injury and dentoalveolar trauma UNILATERAL CROSS BITE UNILATERAL OPEN BITE
Multiple fragmentation With complete loss of occlusion Sublingual hematoma
Unfavorable fracture line Causing displacement Displacement of fractureDirection and intensity of the traumatic force.
Site of fracture.
Direction of fracture line.
Muscle pull exerted on fractured fragments.
Presence or absence of teeth.
Extent of soft tissue wound.
Radiographic featuresOPGPA ViewPNS ViewLateral oblique RadiographOcclusal viewCT scan.
Commonly used. Entire mandible is visualized.OPG viewPA view.
Medial / lateral displacement.
Indicated for Visualizing Medial Displacement Of Condylar Neck
The 4th & 5th MacGregor Line coincides with Mandible
PNS viewBecause of distortion in Symphysis Region inan OPG , an Occlusal View is indicated in Symphysial fractures
Also shows Vertical Favorability of Body Fractures
Occlusal viewCT scan.Condylar fracture.
Cervical spine injury.
Management of mandibular fractures.To be continued..
References.Oral & maxillofacial trauma- Fonseca,vol 1
Maxillofacial Injuries- Rowe & Williams
Textbook of oral & maxillofacial surgery by Peter Ward Booth.
Textbook of oral & maxillofacial surgery by Neelima malik. Killeys - fractures of the mandible