MANDIBULAR OSTEOTOMIES.pptx

ORTHOGNATHIC SURGERY

1. MANDIBULAR OSTEOTOMIES DR DAVIS NADAKKAVUKARAN READER MALABAR DENTAL COLLEGE

2. CONTENT INTRODUCTION CLASSIFICATION MANDIBULAR BODY OSTEOTOMY MANDIBULAR RAMUS OSTEOTOMY COMPLICATION

3. INTRODUCTION Definition of orthognatic surgery is art and science of diagnosis , treatment planning and execution of treatment by combining orthodontics and oral and maxillofacial surgery to correct the muskuloskeltal , dentooseeous and soft tissue deformities of the jaws and associated structures . In the severe skeltal deformities orthodontics may compromise the esthetics and stability and surgery alone ,may compramise the function and stability

4. MANDIBULAR OSTEOTOMY PROCEDURES Mandibular body osteotomies Mandibular body osteotomies –intraoral procedures Anterior body osteotomies Posterior body osteotomies Midsymphysis osteotomies Segmental subapical mandibular surgeries Anterior Posterior Total Genioplasty Augmentation Reduction Strightening lengthening

5. B.Mandibular ramus osteotomies Subcondylar ramus osteotomies Extra oral Intraoral Arching ramus Intraoral modified sagittal split osteotomy

6. PROCEDURES; MANDIBULAR BODY OSTEOTOMY Anterior body osteotomy Performed anterior to the mental foramen Indication Mandibular prognathism with functional posterir occlusion Class III malocclusion with or without anterior open bite Posterior crossbite in dental in nature Incision Removal of the first or second premolars is required Two small vestibular incision in Ist and 2 nd premolar region

7. Procedure After putting incision mucoperiosteal tunneling is carried out superiorly till the alveolar crest and inferiorly till inferir border of area of extraction Periosteal elevator is inserted lingually through the extraction site subperiosteally to protect the lingual soft tissue during osteotomy cut Osteotomy cut Modified retractor placed at the inferior border of the body of mandible Osteotomy cut started in socket at the alveolar margin involving both buccal and lingual cortices going towards the inferior border Cuts are made parellel to each othe

8. Same procrdure repeated on opposite side Occlusal splint tried and cut is modified till desired position is achieved After fit of occlusal splint is achieved , fragments are stabilized at superior border by passing figure of eight wire around neck of canine and premolar and inferiorly by using miniplate Wound is closed by single layer Modified step osteotomy

9. Posterior body osteotomy Osteotomy posterior to mental foramen Indication Missing posterior teeth Class III deformity Corre c tion of crossbite Incision Vestibular incision- one tooth anteriorly and one tooth distal to osteotomy site and is extended posteriorly up to the external oblique ridge for more relaxation

10. Osteotomy cut Channel retractor inserted at the site Cut started superior to neurovascular bundle and finished through both the cortices At the level of bundle , small window is made by removal of removal of only external cortex Neve hook is inserted to pull bundle towards buccal side and lingual osteotomy finished Bundle retracted upward , inferior border cut can be completed Same procedure on other side Occlusal splint is fitted by intraossous wiring or bone plating

11. Mid symphysis osteotomy Used to widen or narrow the anterior arch width Incision Complete vestibular incision Osteotomy cut Thin tapering saw or bur can be used for making cut between two mandibular incisor from the alveolar crest to the inferior border

12. SEGMENTAL SUBAPICAL MANDIBULAR SURGERIES Anterior subapical mandibular osteotomy Indication Correction of mandibular dento alveolar proclination Closing mild anterior open bite Leveling an accentuated curve of spee Correcting mndibular dental arch asymmetry As adjunctive procedure with anterior maxillary osteotomy With mandibular advancement Genioplasty procedure

13. Incision Circum vestibular incision from canine to canine It made into the lip and carried out tangentially down to the bone Subperiosteal dissection is carried to the inferior body and the symphysis region is degloved Osteotomy cut Periosteal elevator is placed on the lingual suface of extraction socket and vertical cut is made from the alveolar crest till the level of premolar root apex through both the cortices . Same procude repeated on the same side Both vertical cut connected by the horizontal subapical osteotomy cut made about 5mm below the anterior teeth apices Fixation by miniplate and wound closed in two layer,mucosal and muscular layer

14. Posterior subapical mandibular osteotomy procedure Indication Uprighting the posterior segment which is extreme linguo –version or buccoversion Closing a premolar or molar spaces Leveling a supraerupted posterior teeth Incision Horizontal vestibular incision Mucoperiosteal flap reflected downwards till the inferior border of the mandible

15. Osteotomy cut Anterior vertical cut –area of missing first premolar or first molar Second vertical cut -behind the last molar is exist Horizontal cut –below the apices of tooth Cut upto the level of neurovascular bundle Buccal cortex above the neurovascular bundle is removed Window extended posteriorly to the distal vertical cut Window is made to cut buccal cortex only and after identification of nerve bundle lingual osteotomy cut is completed Horizontal cut to connect the vertical cut and the entire segment is mobilized Fixing the occlusal splint and placing circummandibular wiring over splint

16. Total subapical mandibular osteotomy Indications To reposition entire mandibular dentoalveolar segment anteriorly , posteriorly or superiorly For lenthening of lower one third of the face Advancing of mandibular dentoalveolar segment Osteotomy cut Horizontal osteotomy – from anteriorly in the symphysis region and proceed posteriorly and It is completed through lingual cortex by placing the guiding finger on lingual side and bur is directed at an angle of 45 degree from buccal to lingual cortex .

17. Vertical osteotomy is made mm posterior to the last molar Buccal cut made first upto bundle and then lingual cut is completed. In advancement cases , chance to overstrech the nerve

18. GENIOPLASTY Augmentation genioplasty To increase the chin projection Can be done by sliding horizontal osteotomy or autogeneous bone graft or alloplastic material Incision Vestibular incision to deglove the entire inferior border of symphysis Periosteal releasing incision

19. Osteotomy cut

20. Reduction genioplasty Three different types of procedures are desired Horizontal osteotomy and set back of the fragment Vertical reduction amounts to determining the movement . Two horizontal osteotomy cut –lower cut is first and then superior cut and bony wedge is removed Vertical reduction and posterior pushback is need in some cases

21. Mandibular ramus osteotomy Subcondylar ramus osteotomies Extra oral Intraoral Arching ramus Intraoral modified sagittal split osteotomy

22. Vertical subsigmoid osteotomy Indication To correct the mandibular prognathism To correct mild mandibular retrognathism Incision Submandibular incision(extra orally) Extended third molar incision (intra oral)

23. Osteotomy cut Antilingula - prevent damage to inferior alveolar nerve Vertical bony cut – from mandibular notch to mandibular foramen –reaching down to mandibular border Decortication of the part of ramus anterior to the osteotomy cut can be made so that when the ramus is pushed back to correct the prognathism Simple fixation using wires for to weeks

24. Inverted L osteotomy Indicated in retrognathic mandible Extraorally by submandibular incision Lateral asepect is exposed Osteotomy cut - first horizontal starting from the anterior border of the ramus base of the coroonoid process extending above mandibular foramen Cut then vertically down to inferior border of ramus Advancement done by using graft Fixation done by transosseous wiring or bone plate

25. C osteotomy Modification of of L osteotomy Difference is in osteotomy cut Cut is stright down to the inferior border of the mandible brought forward in a horizontal direction towards the third molar region

26. INTRAORAL SAGITTAL SPLIT OSTEOTOMY described y obwegeser modification done by hunsuck and dalpont Indication Prognathic mandible correction Retrognathic mandible correction Incision Made third molar region just lateral to the crest of alveolus It extended anteriorly along external oblique ridge upto planned vertical osteotomy cut Diastally extended along anterior border of ramus Lateral surface is exposed upto the lower border Medially subperiosteal disection done till the posterior border of the ramus

27. Osteotomy cut Devided into three;- Horizontal cut – on medial aspect over mandibular foramen Vertical cut-third molar region from exteranl oblique ridge to the inferior border of mandible A cut connecting them both runs along the external oblique ridge Procedure done bilaterally Fixation done by wiring or single plate

28. Complication Injury to inferior alveolar nerve Troublsome bleeding Unfavourable split Avascular necrosis Condylar resorption . Malpositioned proximal segment Shattering of the ramus in case of thin mandible

29. SUBCONDYLAR OSTEOTOMY Incision – preauricular incision or submandibular incision Condylar neck is sectioned obliquely and mandible positioned posteriorly without damaging mandibular foramen

30. GENERAL COMPLICATION Postoperative infection Exposure of hardware Devitalisation of teeth Malunion Malocclusion Relapse Injury to teeth Periodontal problem Respiratory decompensation bleeding

31. REFERENCE Text book of oral and maxillofacial surgery – Neelima Anil Malik Textbook of oral and maxillofacial surgery – Chitra Chakravarthy (2nd edition )

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