Mandibular fractures

fractures of mandible

1. MANDIBULAR FRACTURES Dr ARJUN SHENOY

2. Contents. Introduction. Surgical anatomy History. Epidemiology. Classification systems Clinical features and diagnosis Radiographic features Conclusion. References.

3. Introduction. Maxillofacial injuries. Mandibular fractures – prominence of mandible Occlusion Management.

4. Surgical anatomy Strongest facial bone Parabola shaped bone Angle of curvature is 110-140° Mandible is the 2 nd bone to ossify Energy of 44.6-74.4 kg/m required to fracture the mandible.

5. Weak areas of mandible Junction 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.

6. Age changes of mandible. Mental foramena. child – near inferior border. old age – near alveolar ridge. Ramus angle. child & old – obtuse Alveolar ridge Blood supply

7. Safe 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

8. Distance between I .A. Canal & cortex At bicuspid - 4.0 mm Molar region - 5.9 mm Anteriorly distance Between adjacent Root apices is 3.7 mm Posteriorly distance Between adjacent Root apices is 6.3 mm

9. Champy’s 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.

10. Blood supply. Helps in the healing of fractured bone. Endosteal blood supply via inferior dental artery & veins. Peripheral blood supply - Periosteum

11. Nerve supply. Inferior alveolar nerve Damage - angle & body # Anesthesia or parasthesia of the nerve Recovery / regeneration - 3 to 12 months

12. 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

13. 1860 GILMER GILMERS WIRING & FULL ARCH BARS 1900 MAHE PLATING KIT SIMILAR TO MODERN SYSTEMS 1920 F. RISDON RISDONS WIRING 1961 LUHR DYNAMIC COMPRESSION PLATES 1970 BRONS & BOERING LAG SCREWS 1973 MICHELET MINIPLATES FOR MAND OSTEOSYNTHESIS 1978 CHAMPY MINIPLATE OSTEOSYNTHESIS PRINCIPALS

14. Epidemiology. Etiology:

15. Age. Sex Site

16. CAR ACCIDENTS ASSAULTS BIKE ACCIDENTS

17. Classification General Anatomical Completeness Mechanism of injury Number of fragments Shape of fracture Direction & favorability of treatment Presence or absence of teeth AO classification.

18. 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

19. COMPLEX COMPLICATED They is adjunct injury to the adjacent nerves or major blood vessels , joints. IMPACTED One fragment is firmly driven within the other fragment and clinical movement not appreciated GREENSTICK Only one cortex broken. Common in children PATHOLOGICAL Spontaneous fracture as a result of normal muscle contraction or trauma due to increased weakness of underlying bone . Impacted fracture

20. Dingman & Natvig classification Symphysis fracture Canine region fracture Body of the mandible fracture Angle fracture Ramus fracture Coronoid fracture Condylar fracture Dentoalveolar fracture

21. Direction & favorability of treatment Horizontally Favourable Fracture line runs downward & forward so upward displacement avoided Horizontally Unfavourable Fracture line runs Down Wards and Back Wards so upward Displacement Unrestricted

22. VERTICALLY FAVORABLE VERTICALLY UNFAVORABLE FRACTURE LINE RUNS FROM THE OUTER BUCCAL PLATE OBLIQUELY BACKWARDS AND LINGUALLY , MEDIAL MOVEMENT RESTRICTED FRACTURE LINE RUNS FROM THE INNER LINGUAL PLATE OBLIQUELY BACKWARDS AND BUCCALLY , MEDIAL MOVEMENT UNRESTRICTED

23. 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 III EDENTULOUS PATIENT OPEN REDUCTION / PROSTHESIS

24. AO Classification F NO. OF FRACTURE OR FRAGMENTS L LOCATION OF THE FRACTURE O STATUS OF OCCLUSION S SOFT TISSUE INVOLVEMENT A ASSOCIATED FRACTURES

25. F: NO. OF FRACTURES F0 Incomplete fractures F1 Single fractures F2 Multiple fractures F3 Comminuted fractures F4 Fracture with bone defect

26. L: Location of fracture L1 Pre-canine L2 Canine L3 Post-canine L4 Angle L5 Supra-angular L6 Condyle L7 Coronoid L8 Alveolar process

27. O: Status of occlusion O 0 No malocclusion O 1 Malocclusion O 2 Edentulous mandible

28. A: Associated fracture A 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 III

29. Clinical examination. History Mechanism of injury Extraoral / Intraoral

30. Clinical features. Extensive edema Tenderness. step deformity bone crepitus Facial asymmetry

31. Deviation of jaw Restriction of mouth opening

32. Extensive soft tissue and bony defect

33. 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

34. Mandibular fracture has to be differentiated from extensive Soft tissue injury and dentoalveolar trauma UNILATERAL CROSS BITE UNILATERAL OPEN BITE

35. Multiple fragmentation With complete loss of occlusion Sublingual hematoma Unfavorable fracture line Causing displacement

36. Displacement of fracture Direction 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.

37. Radiographic features OPG PA View PNS View Lateral oblique Radiograph Occlusal view CT scan.

38. Commonly used. Entire mandible is visualized. OPG view

39. PA view. Medial / lateral displacement.

40. Indicated for Visualizing Medial Displacement Of Condylar Neck The 4 th & 5 th MacGregor Line coincides with Mandible PNS view

41. Because of distortion in Symphysis Region in an OPG , an Occlusal View is indicated in Symphysial fractures Also shows Vertical Favorability of Body Fractures Occlusal view

42. CT scan. Condylar fracture. Cervical spine injury.

43. Management of mandibular fractures. To be continued…..

44. 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