IMPACTION - FINAL mandibular impaction.pptx

mandibular impaction.pptx

1. MANDIBULAR 3 rd MOLAR IMPACTIONS Presented by:- Dr Rashmi Kumari MDS 3 rd Year T.P.C.T’S TERNA DENTAL COLLEGE DEPARTMENT OF ORAL AND MAXILLOFACIAL SURGERY

2. CONTENTS INTRODUCTION TERMINOLOGIES DEFINITIONS OF IMPACTION THEORIES OF IMPACTION ETIOLOGY INDICATIONS AND CONTRAINDICATIONS OF REMOVAL OF IMPACTED TOTH CLASSIFICATION OF IMPACTED THIRD MOLARS ASSESSMENT OF IMPACTED THIRD MOLARS SURGICAL PROCEDURE COMPLICATIONS IMPACTED MAXILLARY THIRD MOLAR REFERENCES

3. INTRODUCTION The third molar has been the most widely discussed tooth in the dental literature, and the debatable question “….. to extract or not to extract ” seems set to run into the next century. - Faiez N. Hattab , JOMS, 57: 389-391 (1999). Got their name „Wisdom teeth‟ from the age during which they erupt: 17 to 25. This is the age at which men and women become adults, and, presumably wiser.

4. DEFINITIONS IMPACTED TOOTH Impacted tooth is defined as the tooth which has already passed chronological age of eruption and failed to come to oral cavity inspite of normal eruptive forces due to some mechanical obstruction. American society of oral surgeons 1971

5. According to WHO – An impacted teeth is any tooth that is prevented from reaching its normal position in the mouth by tissue, bone or another tooth. According to ARCHER(1975) – A tooth which is completely or partially unerupted and is positioned against another tooth, bone or soft tissue so that its further eruption is unlikely, described according to its anatomic position. According to ANDERSON(1997)- An impacted tooth is a tooth which is prevented from completely erupting into a normal functional position due to lack of space, obstruction by another tooth or an abnormal eruption path. According to PETERSON A tooth is considered impacted when it has failed to fully erupt into the oral cavity within its expected time period and can no longer reasonably be expected to do so.

6. ERUPTION - defined as the movement of tooth from its developmental position within the jaw toward the functional position within the occlusion. PRIMARY RETENTION- defined as a cessation of eruption before gingival emergence without a recognizable physical barrier in the eruption path and ectopic position. SECONDARY RETENTION- is related to the cessation of eruption of a tooth after emergence without physical barrier in its path or ectopic position of a tooth.

7. ANKYLOSED TOOTH- when the cementum of the tooth is fused to the bone and there is no periodontal soft tissue in between. MALPOSED TOOTH- a tooth, unerupted or erupted that is in abnormal position in the maxilla or mandible.

8. TWO HYPOTHESIS Nature and Nurture Hypothesis: 1. John hunter (1771)- stated that as the successive teeth erupt the jaws grow to make room for them. If the jaws are not big enough then there will not be room for all teeth, and last to erupt will become misplaced. 2. Darwin (1881)-he had previously noted that the posterior dental portion of the jaws always shortened in more civilized races of man and Darwin attributed this to “ civilized mans habitually feeding on soft cooked food”

9. THEORIES OF IMPACTION

10. Orthodontic theory ( Durbeck ): Jaws develop in downward and forward direction. Growth of the jaw and movement of teeth occurs in forward direction,so any thing that interfere with such moment will cause an impaction (small jaw-decreased space). A dense bone decreases the movement of the teeth in forward direction Phylogenic theory : Nature tries to eliminate the disused organs i.e., used makes the organ develop better, disuse causes slow regression of organ. [More-functional masticatory force – better the development of the jaw] Due to changing nutritional habits of our civilization have practically eliminated needs for large powerful jaws, thus, over centuries the mandible and maxilla decreased in size leaving insufficient room for third molars.

11. Mendelian theory: Heredity is most common cause. The hereditary transmission of small jaws and large teeth from parents to siblings. This may be important etiological factor in the occurrence of impaction. Pathological theory: Chronic infections affecting an individual may bring the condensation of osseous tissue further preventing the growth and development of the jaws. Endocrinal theory : Increase or decrease in growth hormone secretion may affect the size of the jaws. The Skeletal theory - Several studies have demonstrated that when there is inadequate bony length, there is a higher proportion of impacted teeth.

12. DEVELOPMENT OF THIRD MOLARS 7-8 yrs: initiation of tooth bud formaton 9 yrs: tooth germ visible in the radiograph 11 yrs: completion of cusp mineralisation- anterior border of ramus 14 yrs: crown development completed 16 yrs: approx. 50% root developed 18 yrs: root development completed 20- 24 yrs: 95% of lower third molars erupt

13. The Belfast Study Group They claim that there may be differential root growth between the mesial and distal roots, which causes the tooth to either remain mesially inclined or rotate to a vertical position depending on the amount of root development. Underdevelopment of mesial root- mesioangular impaction Overdevelopment of mesial root- distoangular impaction

14. ETIOLOGY OF IMPACTION

15. LOCAL CAUSES Berger lists the following local causes of impaction : 1.Irregularity in the position and presence of an adjacent tooth. 2. Density of the overlying or surrounding bone. 3.Long – continued chronic inflammation with resultant increase in density of the overlying mucous membrane. 4. Lack of space due to underdeveloped jaws. 5.Non absorbing, over retained primary teeth. 6. Premature loss of the primary teeth. 7.Acquired diseases, such as necrosis due to infection or abscesses and inflammatory changes in the bone

16. SYSTEMIC Prenatal Heredity Miscegenation Postnatal Causes Rickets Anemia Congenital Syphilis Tuberculosis Endocrine Dysfunctions Malnutrition Rare Causes ClediocranialDysostosis Oxychephaly Progeria Achondroplasia Osteopetrosis Cleft Palate

17. PREDICTION OF THIRD MOLAR ERUPTION Pain Inflammation Food lodgement Trauma to adjacent mucosa Pressure on adjacent tooth Rule out MPDS& TMDs

18. INDICATION OF THIRD MOLAR EXTRACTION

19. PERICORONITIS It refers to the inflammation of soft tissue in relation to the crown of an incompletely erupted tooth including gingiva and dental follicle. Greek word- peri - around Corona –crown itis -inflammation

20. UNRESTORABLE DENTAL CARIES Inability to effectively clean the area Inaccessibility

21. PATHOLOGIES/ PREVENTION OF CYSTS AND TUMORS RISK OF CYST & TUMOR DEVELOPMENT: Most common age : 20- 25 years. Incidence of cyst formation-2.31% (Guven et al,2000) Incidence of dentigerous cyst- 1.6% (Keith,1973) Incidence of ameloblastoma – 0.14- 2% (Shear,1978) Risk of surgical morbidity increases with age.

22. ORTHODONTIC CONSIDERATION Crowding of mandibular incisors Obstruction of orthodontic treatment Interference with orthognathic surgery

23. PATHOLOGIC RESORPTION OF ADJACENT TEETH PERIODONTITIS

24. TEETH UNDER DENTAL PROSTHESIS AUTOGENOUS TRANSPLANTATION

25. INVOLVEMENT IN FRACTURE

26. PROPHYLATIC REMOVAL- In persons who are involved in contact sports. RECURRENT TRAUMA

27. CONTRAINDICATIONS Extreme of age Compromised medical status Probable excessive damage to adjacent structure (unfavorable risk /benefit ratio) Third molars needed as abutments Recently irradiated jaw Tooth in tumour .

28. Absolute contraindications Acute pericoronitis Acute necrotising ulcerative gingivitis Haemangioma , Haemophilia , leukaemia Thyrotoxicosis

29. NATIONAL INSTITUTE FOR CLINICAL EXCELLENCE (NICE) GUIDELINES ON EXTRACTION OF WISDOM TEETH (2000) The practice of prophylactic removal of pathology-free impacted third molars should be discontinued. Surgical removal of impacted third molars should be limited to patients with evidence of pathology The evidence suggests that a first episode of pericoronitis , unless particularly severe, should not be considered an indication for surgery. Second or subsequent episodes should be considered the appropriate indication for surgery.

30. ORDER OF IMPACTED TEETH (ARCHER) Maxillary third molar Mandibular third molar Maxillary cuspids Mandibular bicuspids Supernumerary tooth Maxillary bicuspids Mandibular cuspids Maxillary central incisors Maxillary lateral incisors

31. CLINICAL FEATURES Pain Pericoronitis Mobility of adjacent teeth Unexplained TMJ pain Crowding of lower anterior teeth Trismus Bulge distal to second molar Distal proximal caries on second molar

32. SURGICAL ANATOMY OF MANDIBULAR 3 RD MOLAR Temporalis muscle Buccinator Retromolar foramina

33. MUSCLES TEMPORALIS BUCCINATOR MASSETER MEDIAL PTERYGOID MYLOHYOID

34. MUSCLES Vestibule is formed by the attachment of buccinator : buccally and mylohyoid lingually. Along the anterior border of the ramus – tendinous insertion of temporalis -Excessive stripping of these muscle will cause a hematoma, pus, and trismus. Lingual pouch- perforation of roots along the lingual cortical plate. - may cause fracture of lingual cortical plate - displacement of fractured root fragments below mylohyoid.

35. ARTERIES Facial artery & facial vein run in close approximation with lower 1st molar near the anterior border of masseter. Mandibular vessels in retro molar triangle which supply temporalis tendon. Hemorrhage can occur during surgical removal of impacted tooth if distal incision is not taken laterally towards cheek.

36. NEUROVASCULAR BUNDLE INFERIOR ALVEOLAR NERVES AND VESSELS BLOOD VESSELS-facial artery and anterior facial vein Long buccal nerve Mylohyoid nerve

37. LINGUAL NERVE Pogrel et al ,J oral maxillofac Surg 1995:53:1178

38. LINGUAL NERVE Lingual nerve lies inferior and medial to the crest of the lingual plate of mandible with a mean position of 2.28mm(+/-0.9) below the crest & 0.58mm(+/-0.9) medial to crest - KIESSELBACH& CHAMBERLAIN In 17% of cases it lies superior to the lingual plate

39. Retromolar Foramina and Their Canals The retromolar foramina (RMF) and the retromolar canal (RMC) are anatomic variants in the mandible located distally to the last molar. The retromolar nerve, which runs through the RMC is a type 1 bifidity of the mandibular canal. The RMF is located posteriorly to the last molar in the retromolar trigone , which is bounded anteriorly by the third molar, medially by the temporal crest, laterally by the anterior border of the ramus

40. The nerve that runs through the RMC might arise from the early accessory branches of the inferior alveolar nerve (IAN) or long buccal nerve. This area is commonly invaded during mandibular third molar surgery, autologous bone harvesting, and sagittal split osteotomy. The most common variation of the RMC is a branch of the mandibular canal below the third molar. The nerve travels in a posterosuperior direction and opens in the retromolar fossa those posterior to the third molar

41. CLASSIFICATIONS OF MANDIBULAR THIRD MOLAR IMPACTION

42. CLASSIFICATION OF IMPACTED THIRD MOLAR WINTER’S CLASSIFICATION (1926) According to the position of the impacted third molar to the long axis of second molar Mesioangular Horizontal Vertical Distoangular These may occur simultaneously in: Buccal version Lingual version Torsoversion

43. MODIFIED WINTERS CLASSIFICATION Vertical impaction (10° to -10°) Mesioangular impaction(11° to 79°) Horizontal impaction (80° to 100°) Distoangular impaction ( -11° to -79°) Others (111° to -80°) Buccolingual impaction (any tooth oriented in a buccolingual direction with crown overlapping the roots) Sadeta Šeèiæ et al. Journal of Health Sciences 2013;3(2):151-158

44. CLASSIFICATION BY ARCHER (1975) AND KRUGER (1984) Based on angulation of 3 rd molar Mesioangular Distoangular Vertical Horizontal Buccoamgular Lingoangular Inverted

45. BASED ON NATURE OF OVER LYING TISSUE According to contemporary oral and maxillofacial surgery-Peterson The three types of impactions are: (1) Soft tissue impaction (2) Partial bony impaction (3) Full bony impaction

46. PELL AND GREGORY CLASSIFICATION : 1. Relation of tooth to the ramus of the mandible CLASS I Sufficient space available between anterior border of ascending ramus and distal side of second molar for eruption of the third molar CLASS II The space available between the anterior border of ramus and the distal side of the second molar is less than the MD width of the crown of third molar CLASS III The third molar is totally embedded in bone from ascending ramus due to absolute lack of space

47. 2. Relative depth of the third molar in the bone LEVEL A The highest position of the tooth is on a level with or above the occlusal line LEVEL B The highest position of the tooth is below the occlusal plane, but above the cervical level of second molar LEVEL C The highest position of the tooth is below the cervical level of the second molar

48. COMBINED ADA & AAOMS CLASSIFICATION 07220- Soft tissue impaction that requires incision of overlying soft tissue and the removal of the tooth. 07230- Partially bony impaction that requires incision of overlying soft tissue, elevation of a flap, and either removal of bone and the tooth or sectioning and removal of tooth. 07220 07230

49. 07240- Complete bony impaction that requires incision of overlying soft tissue, elevation of a flap, removal of bone, and sectioning of tooth for removal 07241- Complete bony impaction with unusual surgical complication that requires incision of overlying soft tissue, elevation of a flap, removal of bone , sectioning of the tooth for removal, and /or presents unusual difficulties and circumstances. 07240

50. KILLEY & KAY'S CLASSIFICATION Based on angulation and position Vertical Mesioangular Distoangular Horizontal Transverse Buccoangular Linguoangular Inverted Aberrant positions

51. Based on state of eruption Erupted Partially erupted Unerupted Soft tissue impaction Complete bony impaction Based on number of roots Unfavorable impaction- Mesial curvature of roots Multiple roots Favorable impaction- Fused roots Distal curvature of roots

52. PRE- OPERATIVE ASSESSMENT CLINICAL ASSESSMENT General assessment Age/ sex Systemic condition Drug history Anesthesia history General physical examination

53. Extra oral examination Facial form & profile Cheek bulk Swelling Presence of Sinus/ fistula Lymph node Trismus

54. Intra oral examination Soft tissues Size of rima oris (mouth opening) Position of mandible Tongue size Extensibility of lips & cheeks Soft tissue trauma Hard tissues Dentition status External oblique ridge

55. Assessment of impacted teeth Status of eruption Periodontal status External and internal oblique ridge Relationship with adjacent teeth Soft tissue covering Occlusal relationship with opposing tooth

56. RADIOGRAPHIC INVESTIGATIONS A good radiograph helps to plan out the surgical procedure, rule out and pathologies like cystic changes,eruption predilection & also helps to visualize the proximity of vital structures. Routine radiographs include: Intraoral –IOPAR, Bite wing , Occlusal radiograph Extra oral –OPG, Lateral cephelometric Digital imaging –CT, CBCT

57. INTRA ORAL RADIOGRAPHS Indications- Tooth in alveolus Adequate mouth opening Tube shift Relationship with IAN Bisecting angle technique X- ray film stabilized against the teeth and supporting lingual alveolar mucosa

58. BITEWING RADIOGRAPH For visualising class1 and class2 impacted mandibular 3 rd molar. Central rays are directed through the crown of 2 nd molar with zero degree vertical angulation.

59. EXTRA ORAL RADIOGRAPHS Panoramic radiographs Lateral cephalometric skull projection Lateral oblique view of mandible Indications Restricted mouth opening Impacted tooth in aberrant position Rule out pathology Study the relationship to inferior alveolar nerve, inferior border of mandible

60. Specialized techniques COMPUTED TOMOGRAPHY Impacted tooth in ectopic position- distant from oral cavity Associated with neoplastic or inflammatory process with morbidity in contigious tissues

61. Cone beam computed tomography

62. RADIOGRAPHIC ASSESSMENT (a) Access. (b) Depth and position of the tooth. (c) Root pattern of impacted tooth. (d) Shape of crown. (e) Texture of investing bone. (f) Relation to inferior alveolar canal. (g) Root pattern and position of second molar.

63. Winters “WAR” lines White line : Line joining the occlusal surfaces/highest cusps tips of all erupted molars, extending up to the ramus. It indicates the difference in occlusal level of second and third molars. Amber line: Represents the bone level distal to the 3rd molar, extended anteriorly along the crest of interdental septum. This line denotes the alveolar bone covering the impacted tooth and the portion of the tooth not covered. Red Line: Drawn perpendicular from Amber line to the imaginary point of application of elevator on the 3rd molar. It indicates the amount that will have to be removed before elevation i.e. the depth of the tooth in bone and the difficulty encountered in removing the tooth. Length more than 5mm - extraction is difficult. Every additional millimeter renders the removal of the Impacted tooth 3 times more difficult.

64. THE ‘RED LINE’ CONUNDRUM:CONCEPT BEYOND ITS EXPIRY DATE Change of angulation of the film causes the ‘‘red-line’’ to change in length significantly. The red-line in B is shorter by ( 30 % ) than in A with a 15 change in angulation of the film. The ‘‘Red Line’’ Conundrum: A Concept Beyond Its Expiry Date? Sanjeev Kumar • Mahendra P. Reddy • Lokesh Chandra • Alok Bhatnagar : JMOS 02 aug 2013

65. PEDERSON’S DIFFICULTY INDEX Very difficult: 7 to 10 Moderataly difficult: 5 to 7 Minimally difficult: 3 to 4 Scoring Mesio angular 1 Horizontal 2 Vertical 3 Distoangular 4 Level A 1 Level B 2 Level C 3 Class I 1 Class II 2 Class III 3 Large bulbous crown increases the difficulty

66. Category Score 1. Winters classification Horizontal Distoangular Mesioangular Vertical 2 2 1 2. Height of mandible 1-30mm 31-34mm 35-39mm 1 2 3. Angulation of 2nd molar 1° - 59° 60° - 69° 70° -79° 80° - 89° 90°+ 1 2 3 4 4. Root shape Complex Favourable curvature Unfavourable curvature 3 1 2 5. Follicles Normal Possibly enlarged Enlarged Impaction relieved -1 -2 -3 6. Path of exit Space available Distal cusp covered Mesial cusp covered Both cusp covered 1 2 3 33 WHARFE ASSESMENT

67. RELATIONSHIP OF INFERIOR ALVEOLAR NERVE TO THE ROOTS OF THE THIRD MOLAR. Darkening of root Deflection of root Narrowing of root Dark & Bifid apex Rood JP , Shehbab BA-BJOMS 1998:28:20

68. Interruption of white Narrowing of canal Diversion of canal line of canal Rood JP , Shehbab BA-BJOMS 1998:28:20

69. By NORTJE et al.,1977 Type I: Bilaterally single high mandibular canals-single high canals either touching or within 2 mm of the apices of 1 st and 2 nd permanent molars. Type II: Bilaterally single intermediate canals-single canals not fulfilling the criteria for either high or low canals Type III: Bilateral single low canals-single canals either touching or within 2mm of the cortical plate of the lower border of the mandible Type IV: Variations including-asymmetry,duplications and absence of mandibular canals CLASSIFICATION OF MANDIBULAR CANAL

70. SURGICAL PROCEDURE ODONTECTOMY

71. Surgical procedure The surgical procedure for the extraction of impacted teeth includes the following steps: 1. Asepsis and isolation 2. Local anesthesia/ general anesthesia 3. Incision-flap design 4. Reflection of mucoperiosteal flap 5. Bone removal 6. Sectioning (division) of tooth 7. Elevation and tooth removal 8. Debridement and smoothening of bone 10. Closure-suturing

72. Instruments Mouth mirror Probe No. 15 blade on a Bard Parker handle. Mosquito artery forceps Retractors Chisel Bur: rose head, straight fissure Elevators forceps Bone file Needle holder Tissue forceps Scissors Drape Syringe

73. ISOLATION AND ASEPSIS

74. ANESTHESIA Choice of anesthesia Apprehension level The patient’s acceptance of the procedure The length and technical difficulty of the procedure Patient’s preference and risk to benefit ratio

75. Indications for general anesthesia Fear of pain during the procedure Emotionally unstable patient Anticipated lengthy procedures Removal of all four impacted molars in one sitting Uncooperative patients Allergy to LA Tooth in aberrant position

76. DIFFERENT TYPES OF INCISION AND FLAP DESIGN

77. SHORT ENVELOPE LONG ENVELOPE L-SHAPED INCISON BAYONET SHAPED INCISION TRAINGULAR FLAP WARDS INCISION MODIFIED WARDS INCISION GROOVE AND MOORE INCISION S SHAPED INCISION COMMA SHAPED INCISION SZMYD FLAP MODIFIED SZMYD BERWICKS TONGUE FLAP GURALNIK HORIZONTAL INCISION DONLON TRINTA MOTAMEDI

78. The incision having 3 parts - LIMB A: The anterior incision started from buccal sulcus approx. at the junction of posterior and middle third of 2 nd molar, passes upwards extended upto the distobuccal angle of the 2 nd molar at the gingival margin . LIMB B:It was carried along the gingival crevise of third molar extending upto the middle of exposed distal surface of the tooth LIMB C: Started from a point where intermediate gingival incision ended and was carried laterally . This arm should be a pprox 19 mm long. PARTS OF INCISION

79. LIMB C - not to be extended too distally Bleeding from buccal vessels & other vessels Postoperative trismus – temporalis muscle damage Herniation of buccal fat pad Damage to lingual nerve (lingual extension) In case of unerupted tooth ,intermediate incision is not needed. The limb A is extended upto the middle of the distal surface of the 2nd molar.

80. Incision-flap design Ward’s incision Modified ward’s incision

81. ENVELOPE FLAP Extends from the mesial papilla of the mandibular first molar and passes around the neck of the teeth to the disto buccal line angle of the second molar. Now the incision line extends posteriorly and laterally upto the anterior border of the mandible. Its anterior extension is directly proportional to the depth at which the impacted tooth is present deeper the tooth, longer the Ant extension Advantage Easier to close and heal better

82. TRIANGULAR FLAP This flap is the result of an L-shaped incision with a horizontal incision made along the gingival sulcus and a vertical or oblique incision. The vertical incision begins approximately at the vestibular fold and extends to the interdental papilla of the gingiva. Advantages: Good blood supply, Satisfactory vision, Good stability & reapproximation Disadvantages: Limited access, Tension builds when flap held with retractor, and it causes a defect in the attached gingiva

83. COMMA SHAPED INCISION Starting from a point , posterior to the distal aspect of the preceding second molar, the incision is made in an anterior direction. Incision is made to a point below the second molar, from where it is smoothly curved up to meet the gingival crest at the distobuccal line angle of the second molar. The incision is continued as a crevicular incision around the distal aspect of the second molar (a distolingually based flap).

84. S SHAPED INCISION Incision was made from the retromolar fossa across the external oblique ridge curving down through the attached mucoperiosteum to run along the reflection of the mucous membrane to the anterior border of the first permanent molar.

85. VESTIBULAR TONGUE SHAPED FLAP Berwick in 1986 designed a vestibular tongue shaped flap. Extended into the buccal shelf of the mandible. For the pedicle flap an incision distal to the third molar was extended approximately 1 cm and then curved towards the buccal sulcus allowing for rotation of the flap and primary closure over sound bone. Prior to closure, the gingival papilla distal to the second molar was removed and the apex of the pedicle de-epithelialised

86. Principles of flap design Incisions should avoid anatomical structures, such as major nerves or blood vessels. Incisions far enough away from the surgical are a- The wound margins should rests on sound bone The base of the flap should be wider than the apex to ensure adequate blood supply. A firm pressure upon a sharp scalpel should be used so that both the mucosa and periosteal layers of the gingiva are incised down to bone . MUCOPERIOSTEAL FLAP

87. Incisions are made in one operation, as extensions. Cut the soft tissues at right angles to the surface of underlying bone. The Flap should be made large enough to provide for visibility, accessibility and adequate room for instrumentation. The vertical releasing (relaxing) incision should be avoided if the horizontal incision will provide adequate access. This is because the vertical releasing cut reduces the blood supply to the flap and cause added discomfort. The vertical releasing incision, if needed, should be made at a line angle to maintain the integrity of the interdental papilla.

88. REFLECTION OF MUCOPERIOSTEAL FLAP Reflection of the flap begins at the papilla. The end of the periosteal elevator begins a reflection. The sharp end is slipped underneath the papilla in the area of the incision and turned laterally to pry the papilla away from the underlying bone. This technique is used along the entire extent of the free gingival incision. Once the flap reflection is started, the broad end of the periosteal elevator is inserted at the middle corner of the flap, and the dissection is carried out with a pushing stroke, posteriorly and apically. This facilitates the rapid and atraumatic reflection the soft tissue flap

89. BONE REMOVAL BUR TECHNIQUE Postage stamp technique Moore and Gillbe’s technique Guttering technique Bowdler Henry’s( Lateral trephination(1969) CHIESEL AND MALLET Window technique Lingual split technique Shaving technique Distal lingual split technique Aim: To expose the crown by removing the bone overlying it. To remove the Bone obstructing the pathway for removal of the impacted tooth Types: By consecutive sweeping action of bur(in layers). By chisel or osteotomy cut (in sections). Amount to be removed: Bone should be removed till we reach below the height of contour, where we can apply the elevator. Extensive bone removal can be minimized by tooth sectioning.

90. BUCCAL GUTTERING TECHNIQUE Once the soft tissue is elevated and retracted, the surgeon must make a judgment concerning the amount of bone to be removed. Bone must be removed in an atraumatic, aseptic, and non heat producing technique, with as little bone removed and damaged as possible. The amount of bone that must be removed varies with the depth of impaction, the morphology of roots, and the angulation of tooth. The speed of micromotor should be 12000- 20000 rpm. bur used is #701 - diameter of 1.2mm. #702-diameter-1.6mm #703-diameter- 2.1mm

91. REMOVAL OF OVERLYING BONE A large round bur ( No. 8 ) is desirable, because it is an end cutting bur and can be effectively used for drilling with a pushing motion. The tip of a fissure bur ( No. 703 ) does not cut well, but the edge rapidly removes bone and quickly sections teeth when used in lateral direction. The bone on the occlusal aspect of the tooth is removed first to expose the crown of the tooth. Then the cortical bone on the buccal aspect of the tooth is removed down to cervical line.

92. Exposure of the crown of the tooth using a round bur.

93. Postage stamp technique In this technique a row of small holes is made(at 2-3mm equidistance) with a small bur and then joined together either with bur or chisel cuts.

94. Moore & Gillbe’s Collar Technique Conventional technique of using bur. Rosehead round bur no.3 is used to create a gutter along the buccal side & distal aspect of tooth. A point of elevation (mesial purchase point) is created with bur. Amount of bone sacrificed is less. Can be used in old patient. Convenient for patient.

95. Lateral Trepanation Technique Bowlder Henry Employed to remove any partially formed unerupted 3 rd molar that has not breached the overlying hard & soft tissues. Age 9-18 yrs GA/LA with sedation. Excellent PDL healing on distal surface of 2 nd molar. Bone healing is excellent as there is no loss of alveolar bone around 2 nd molar. Disadvantage – increased buccal swelling

96. CHISEL TECHNIQUE THROUGH BUCCAL APPROACH Elevation of mucoperiosteal flap Vertical limiting cut -5-6mm Oblique cut -45 deg Removal of triangular plate of bone Point of application of elevator Distolingual bone not fractured parallel to internal oblique ridge due to the risk of fracture extending upto the coronoid

97. LINGUAL-SPLIT TECHNIQUE Described by Sir William Kelsey Fry (1933). Later popularized by Terence G ward(1956) Specially for lingually placed tooth . Modified by Dr. Davis & Lewis in 1960   SURGICAL BASIS OF LINGUAL SPLIT TECHNIQUE Whenever tooth is extracted Lingual cortical plate is resorbed

98. INCISION VERTICAL STOP CUT H O RIZON T AL CUT SPLIT OF DI S T OLINGUAL BONE REMOVAL OF BUCCAL & DI S T OLIN G U A L BONE E L E V A TION REMOVAL OF DI S T OLIN G U A L BONE CLOSURE LINGUAL SPLIT TECHNIQUE

99. Modified Lingual Split Technique For Removal Of Mandibular Third Molar (Dr. Davis 1979) Not to separate the mucoperiosteom from lingual area of bone Kamanishi modification: Do not raise the lingual flap Advance to the lingual side under the bone only to the extent which is necessary. Lewis modification: Flap was made lingual to second molar instead of third. Vertical lingual step cut just distal to second molar. Lingual plate was hinged like an osteoplastic flap. It is considered as combination of both lingual and buccal approach

100. TOOTH DIVISION TECHNIQUE Kelsey Fry To reduce the removal of large amount of bone Avoid damage to adjacent structures Decreases dead space Allows portions of tooth to be removed separately with elevators Direction depends primarily on angulation of impacted tooth With a bur, tooth is sectioned 3/4 th toward lingual aspect

101. A line is drawn from the mesiolingual cusp till the distal root of the impacted third molar. Half the distance measured is taken as the radius and an arc is drawn. If the arc touches the 2 nd molar indicates locking of tooth. Then sectioning is mandatory. Mesio distal diameter of crown and mesiodistal width of roots are more than the space for exit of the tooth . CRITERIA FOR SECTIONING OF TOOTH

102. SECTIONING OF TOOTH Reduces the amount of bone removal required prior to elevation of tooth. Reducing the risk of damage to the adjacent tooth. Once sufficient amount of bone removed, the surgeon should access the need to section the tooth. The direction in which the impacted tooth should be divided depends primarily on the angulation of the impacted tooth & root curvature.

103. SECTIONING OF TOOTH The sectioning can be performed with a bur or chisel. The bur is used by most surgeons, but if a chisel is used it must be sharp. When the bur is used, the tooth is sectioned three- fourth of the way towards the lingual aspect. A straight elevator is inserted into the slot made by the bur and rotated to split the tooth.

104. Sectioning of the crown of an impacted tooth, in the buccolingual direction, which extends as far as the intraradicular bone.

105. A. buccal and distal bone are removed to expose crown of tooth to its cervical line . B. The distal aspect of the crown is then sectioned from tooth. Occasionally it is necessary to section the entire tooth into two portions rather than to section the distal portion of crown only C . A small straight elevator is inserted into the purchase point on mesial aspect of 3 rd molar, & the tooth is delivered with a rotational and level motion of elevator. MESIOANGULAR IMPACTION

106. A. When removing a vertical impaction, the bone on the occlusal, buccal, and distal aspects of the crown is removed, and the tooth is sectioned into mesial and distal portions. B. The posterior aspect of the crown is elevated first with a Cryer elevator inserted into a small purchase point in the distal portion of the tooth. C. A small straight no. 301 elevator is then used to lift the mesial aspect of the tooth with a rotary and levering motion. VERTICAL IMPACTION

107. Removal of distal and buccal underlying bone The crown is sectioned from the roots of the tooth and is delivered from socket. C, The roots are delivered together or independently with a Cryer elevator used with a rotational motion. Saperation of root into 2 parts - occasionally the purchase point is made in the root to allow the Cryer elevator to engage it. D, The mesial root of the tooth is elevated in similar fashion HORIZONTAL IMPACTION

108. Removal of mesial & distal boen. It is important to remember that more distal bone must be taken off than for a vertical or mesioangular impaction. The crown of the tooth is sectioned off with a bur and is delivered with straight elevator C, The purchase point is put into the remaining root portion of the tooth, and the roots are delivered by a Cryer elevator with a wheel and- axle motion. If the roots diverge, it may be necessary in some cases to split them into independent portions DISTOANGULAR IMPACTION

109. SMOOTHENING & DEBRIDEMENT OF SOCKET Attention must be given to debriding the wound of all particulate bone chips and debris. Wound should be irrigated with sterile saline, taking special care to irrigate thoroughly under the reflected soft tissue flap. Remove any remaining dental follicle and epithelium. The bone file is used to smooth any sharp, rough edges of bone. A final irrigation and a thorough inspection should be performed before the wound is closed.

110. SURGICAL CLOSURE WEDGE REMOVAL Remove triangular wedge of soft tissue immediately posterior to second molar- surgical drainage Excess tissue- elliptical incision

111. Closure of soft tissue flap Return soft tissue flap to the original position Stabilize the flap to permit repair Resecure periodontal/ gingival attachments

112. Intra Operative During incision Injury to facial artery Injury to lingual nerve Hemorrhage During bone removal Damage to second molar Slipping of bur into soft tissue & causing injury Extra oral/ mucosal burns Fracture of the mandible when using chisel & mallet Subcutaneous emphysema During elevation or tooth removal Luxation of neighbouring tooth/ fractured restoration Soft tissue injury due to slipping of elevator Injury to inferior alveolar neurovascular bundle Fracture of mandible Forcing tooth root into submandibular space or inferior alveolar nerve canal Breakage of instruments TMJ Dislocation COMPLICATIONS

113. Immediate Hemorrhage Pain Edema Drug reaction Delayed Alveolitis Infection Trismus POST OPERATIVE COMPLICATIONS

114. HAEMORRHAGE The overall complication rate associated with the removal of third molars is 7% to 10%, and the risk of hemorrhage is 0.2% to 1.4%. Hemorrhage from the mandibular molars is more common than bleeding from the maxillary molars (80% and 20%, respectively) because the floor of the mouth is highly vascular. Furthermore, the distolingual aspect of the mandibular third molar region is the most highly vascularized site, and this should be taken into consideration when all third molars are to be removed. This area may encompass an accessory artery emanating from the lingual aspect of the mandible, and bleeding may be profuse if this vessel is cut.

115. STYPTICS AND LOCAL AGENTS