IMPACTION OF MANDIBULAR 3RD MOLAR & IT’S MANAGEMENT ls.pptx

Impactin

1. IMPACTION OF MANDIBULAR THIRD MOLAR & IT’S MANAGEMENT SUBMITTED BY; LEKSHMI S AJIT ROLL NO:11 FINAL YEAR PART I

2. CONTENTS INTRODUCTION THEORIES OF IMPACTION AETIOLOGY OF IMPACTION INDICATIONS FOR REMOVAL CONTRAINDICATIONS FOR REMOVAL CLASSIFICATION CLINICAL EVALUATION RADIOLOGICAL ASSESSMENT SURGICAL REMOVAL OTHER TECHNIQUES IN MANDIBULAR 3 RD MOLAR REMOVAL CONCLUSION REFERENCE

3. INTRODUCTION Impacted tooth is a tooth which is completely or partially unerupted , is positioned against another tooth , bone or soft tissues so that its further eruption is unlikely & described according to its anatomic position. Teeth become impacted mainly due to inadequate dental arch length & space in which to erupt. Third molars are most frequently impacted as they are the last teeth to erupt

4. THEORIES OF IMPACTION ORTHODONTIC THEORY growth of the jaw & the movement of teeth occurs in forward direction , anything that interferes with such movement will cause an impaction. NODINE’S PHYLOGENIC THEORY Elimination of unused tooth which causes congenital absence of third molars. MENDELIAN THEORY Inherits small jaws from one parent & a complement of large teeth from other i.e , small mandible with impaction of 2 nd & 3 rd molars.

5. PATHOLOGICAL THEORY Osteosclerosis of third molar area bring condensation of osseous tissue further preventing growth and development of jaws. ENDOCRINAL THEORY An imbalance of endocrine activity leads to lack of growth of jaws. NATURE AND NURTURE THEORY A.J Mac Gregor explains that impaction can occur due to a mismatch in size and shape of teeth and jaws .

6. AETIOLOGY OF IMPACTION LOCAL CAUSES Irregularity in position and pressure of adjacent tooth. Density of overlying or surrounding bone. Arch length and tooth size discrepancy Dilaceration Over retained deciduous teeth Ectopic position of tooth bud Localised chronic inflammation

7. SYSTEMIC CAUSES Prenatal causes : heredity Postnatal causes : rickets, anemia, tuberculosis, malnutrition, congenital syphilis , endocrine dysfunctions. Rare conditions : progeria, cleft palate ,osteopetrosis , oxycephaly

8. INDICATIONS FOR REMOVAL Infections Periodontal diseases Dentigerous cyst formation External resorption of 2 nd molar Buccoverted impacted molars Prophylactic removal Atypical pain Fracture of mandible in 3 rd molar region

9. CONTRAINDIACTIONS FOR REMOVAL Medical history Deeply impacted third molars in patients with no history of any bony pathology to avoid damage to vital structures Partially erupted tooth which can be used as an abutment in FPD Impacted teeth which are likely to erupt successfully.

10. CLASSIFICATION A) BASED ON NATURE OF OVERLYING BONE Soft tissue impaction : presence of dense fibrous tissues overlying the teeth prevents normal eruption. Hard tissue impaction : teeth fail to erupt due to obstruction caused by overlying bone.

11. WINTER’S CLASSIFICATION Mesioangular : long axis of 3 rd molar bisects long axis of 2 nd molar Distoangular : long axis of 3 rd molar away from long axis of 2 nd molar Horizontal : long axis of 3 rd molar bisect long axis of 2 nd molar at right angle Vertical : long axis of 3 rd molar runs parallel to long axis of 2 nd molar

12. PELL AND GREGORYS CLASSIFICATION Based on their relationship with the anterior border of the mandible Class 1 : the anteroposterior diameter of the tooth is equal to the space between the anterior border of ramus of the mandible and distal surface of second molar tooth Class 2 : a small amount of bone covers the distal surface of the tooth and the space is inadequate for eruption of the tooth ie , mesiodistal diameter of the tooth is greater than the space available Class 3 : tooth is located completely within the ramus of the mandible least accessible

13. B . Based on the amount of bone covering the impacted tooth and relation to occlusal plane Position A :occlusal plane of the impacted tooth is nearly in the same level as the occlusal level of the adjacent second molar tooth Position B : occlusal plane of the impacted tooth is in the midway between the cervical line and the occlusal plane of the adjacent second molar tooth Position C : occlusal plane of the impacted tooth below the level of cervical line of the second molar tooth C. Based on long axis of impacted tooth Same as winters classification B . Based on the amount of bone covering the impacted tooth and relation to occlusal plane Position A :occlusal plane of the impacted tooth is nearly in the same level as the occlusal level of the adjacent second molar tooth Position B : occlusal plane of the impacted tooth is in the midway between the cervical line and the occlusal plane of the adjacent second molar tooth Position C : occlusal plane of the impacted tooth below the level of cervical line of the second molar tooth C. Based on long axis of impacted tooth Same as winters classification

14. CLINICAL EVALUATION GENERAL EXAMINATION Presence of any systemic disorders/diseases Age & general fitness Presence of facial swellings & enlarged tender lymph nodes indicates active infection & treatment should be deferred

15. LOCAL EXAMINATION Eruption status of impacted tooth Occlusal relationship Presence of local infection like pericoronitis Periodontal status Resorption of 2 nd molars Caries in or resorption of 3 rd molars and adjacent tooth Soft tissue assessment TMJ function-mouth opening External and internal oblique ridge

16. FACTORS COMPLICATING THE REMOVAL OF MANDIBULAR 3 RD MOLAR Pre existing joint problem-risk of dislocation or derangement Position of impacted 3 rd molar Thickness of oblique ridge Surrounding bone-dense bony socket resists easy removal

17. RADIOLOGICAL ASSESSMENT TYPES OF RADIOGRAPHS USED 1.Intraoral periapical radiograph 2.Bitewing 3.Occlusal radiograph 4.Lateral oblique 5.OPG 6.CBCT

18. FRANK’S TECHNIQUE OF LOCALISING MANDIBULAR CANAL 1 st IOPA taken with x-rays directed perpendicular to the tooth with no vertical or horizontal angulations 2 nd IOPA taken with x-rays directed 25 degree below plane of occlusion If canal on buccal side of roots will appear to move upward on the roots If mandibular canal lies on lingual to impaction,it will move downward in relation to roots of 3 rd molar

19. INTERPRETATION OF RADIOGRAPH ASSESSMENT OF ACCESS Determined by inclination of radiopaque line caused by external oblique ridge When the radiopaque line is horizontal access is easy,when it is more vertical,access is poor. If radiopaque line is behind the impacted tooth access is good ,if it is situated in front of the tooth access is poor.

20. ASSESSMENT OF POSITION AND DEPTH WAR LINES : 3 imaginary lines drawn on standard radiograph with different colors like white,amber,red . White line -drawn along occlusal surface of erupted mandibular molars and extended over third molar region posteriorly. It indicates depth of tooth within mandible & relationship of occlusal surface of impacted tooth with the erupted molars Amber line - drawn from the surface of bone on the distal aspevt of 3 rd molar to the crest of the interdental septum between the 1 st & 2 nd molar. This line represents margin of alveolar bone covering 3 rd molar

21. Red line - drawn perpendicular from amber line to an imaginary point of application of elevator,usually on CEJ on the mesial surface of impacted tooth <5mm-less difficult;for every 1mm increase difficulty increses by 3 times >5mm –advised under GA;>9mm –very difficult

22. ASSESSEMENT OF ROOTS OF IMPACTED TEETH LENGTH OF ROOT Ideal time to remove the impacted teeth is when root is 2/3 rd formed FUSION OF ROOT Fused conical roots are easier to remove than widely separated roots WIDTH OF ROOTS Mesiodistal width greater than cervical width indicate difficulty in removal ROOT OF 2 ND MOLAR If 2 nd molar roots are smaller care must be taken not to luxate the second molar during elevation

23. ASSESSMENT OF RELATIONSHIP WITH INFERIOR ALVEOLAR NERVE Seven radiological signs by Howe and Poyton (1960)

24. SURGICAL REMOVAL OF IMPACTED 3 RD MOLAR Depends on: Type and degree of impaction Amount of soft tissue exposure to aid removal of bone Amount and technique of bone removal Odentectomy ANAESTHESIA Local anaesthesia by nerve block of IAN,lingual nerve GA in deeply situated tooth

25. INCISION ward’s and modified ward’s incision

26. MUCOPERIOSTEAL FLAP Requirements: - adequate exposure of operating site - base of flap should be wide so that soft tissues get adequate blood supply - shouldn’t be extended far distobuccally,may injure buccal vessels - incision should not damage any vital structures Flaps used are : envelope flap L-shaped flap bayonet flap triangular flap

27. ELEVATION OF FLAP Flap elevated using periosteal elevator Once the flap has been raised appropriate retractors are used to retract the flap. REMOVAL OF BONE Removal of bone with bur: MOORE GILLBE COLLAR TECHNIQUE Bur is used to create a gutter around the neck of the tooth.On the buccal and distal aspect bone must be removed to expose the entire crown till CEJ. Removal of bone with chisel: Buccal bone carved away by chiseling. When removing bone using chisel, mandible should be adequately supported

28. REMOVAL OF TOOTH Using straight elevator force is applied on the mesial CEJ of the impacted tooth so that tooth rotates in an arc. Sectioning of tooth in multiple segments helps in easy removal. DEBRIDEMENT OF WOUND AND WOUND CLOSURE Wound is debrided to remove particulate bone chips and debris using periapical curette. Sharp margins of bone smoothened using bone file Wound is then closed with sutures Initial suture is placed on the distal aspect of 2 nd molar. Additional sutures placed in anterior and posterior limbs of incision.

29. OTHER TECHNIQUES IN THIRD MOLAR REMOVAL LATERAL TREPHINATION TECHNIQUE Described by Bowdler -Henry Local anesthesia is secured , external oblique ridge is palpated and s-shaped incision is made Incision from retromolar fossa-external oblique ridge-mucous membrane above vestibule-anterior to first permanent molar Full thickness is elevated Buccal cortical plate over 3 rd molar is trephined At posterior end, 2 nd cut is made through the outer plate at 45degree Buccal plate is fractured and impcted tooth is delivered out

30. LINGUAL SPLIT TECHNIQUE Introduced by Sir William Kelsey Fry Incision made on 3 rd molar region- mucoperiosteal flap is elevated on buccal side Chisel is placed horizontally with the bevel facing downwards Point of application of elevator is made with chisel by excising triangular piece of bone Distolingual bone fractured using chisel held at a 45 degree Peninsula of bone which remains distal to the tooth & between buccal and lingual cuts is excised Lingual plate is fractured and lifted from the wound Bony edges are smoothened with file,wound is irrigated with salina and closed with sutures

31. CONCLUSION All impacted tooth must be removed unless removal is contraindicated. Extraction should be performed as soon as the dentist determines that the tooth is impacted . Removal of impacted tooth becomes more difficult with advancing age .If removal of impacted teeth is deferred ,surgery is more likely to be complicated and hazardous for the patient.

32. REFERENCE TEXTBOOK OF ORAL AND MAXILLOFACIAL SURGERY – THIRD EDITION- S M BALAJI