IMPACTION

BY - Dr. James

DEFINITIONImpacted tooth is the tooth that has failed to erupt completely or partially to its correct position in thedental arch and its eruption potential has been lost.

Severely impacted wisdom tooth CT scan - upper right

IMPACTED TEETH

Mandibular third molar

Maxillary third molar

Maxillary canine

Mandibular premolar

Maxillary premolar

Mandibular canine

Maxillary central incisors

Maxillary lateral incisors

Order of frequency of impacted teeth

CAUSES OF IMPACTION IN TEETH

INADEQUATE SPACE IN THE DENTAL ARCH FOR ERUPTION

The physiologic theory Due to evolution, there may not be room for 3rd molar to emerge in oral cavity.

Mendelian theory Role of genetic variations. If individual genetically receives a small jaw from one of the parents and/or large teeth from the other parent.

CAUSE OF IMPACTION OF A TOOTH CAN BE DIVIDED INTO :-

LOCAL CAUSE SYSTEMIC CAUSE

• Obstruction for eruption• Lack of space in the dental arch > crowding > supernumerary teeth• Ankylosis of primary and permanent teeth• Nonabsorbing over-retained deciduous teeth• Nonabsorbing alveolar bone• Ectopic position of tooth bud• dilaceration of roots • Associated soft tissue or bony lesions• Habits involving tongue, finger, thumb, cheek, pencil, etc…!

• Prenatal causes - heredity• Postnatal – ricketts, anaemia, tuberculo -sis, congenital syphilis, malnutrition• Endocrinal disorders of thyroid, parathi - roid, pituitary glands likes hypothiroid - ism, achondroplasia, etc. Here the primary retention of teeth due to lack of osteoclastic activity, which dose not provide resorption of the bone overlying the developing tooth• Hereditary-linked disorders Down synd. , hurler’s syndrom, osteopetrosis. Cleidocranial disostosis, cleft palate etc. Here failure of the overlying bone to resorb and develop an eruption path way is absent

INDICATION FOR REMOVAL OF IMPACTED TEETH

Recurrent pericoronitis/ pain / infection / caries pericoronitis

Deep periodontal pocket

Prior to orthodontics treatment – to control the tooth

crowding in the

mandible

Prevent of root resorption and caries of adjacent II molar

Management of cysts of tumours , abscess of odontogenic

origin

Prevention of pathological fracture

Preparation of orthognathic surgery

Management of preprosthetic concerns

Impacted teeth in the line of fracture

Prophylactic removal

CLASSIFICATION OF IMPACTED TEETH

Maxillary and mandibular third molar molars are classified radio graphically by radio graphically, depth and arch length or relationship to the anterior aspect of the ascending mandibular ramus. WINTER’S CLASSIFICATION

ANGULATION According to the position of the impacted third molar to the long axis of the second molar. The winter’ classification suggest

Mesioangular

Horizontal

Vertical

Distoangular

Buccoangular

linguoangular

Unusual position

DEPTH As per relation to the occlusal surface of the adjoining second molar of theimpacted maxillary or mandibular third molar .

Position A : The highest position of the tooth is on a level with or above the occlusal line.

Position B : Highest position is below the occlusal plane, but above the cervical level of the second molar.

Position C : Highest position of the tooth is below the cervical level of the second molar

PELL AND GREGORY CLASSIFICATION Based on the space available distal to the second molar

Class I : Sufficient space available between the anterior border of the ascending ramus and the distal side of the second molar for eruption of the third molar

Class II : The space available between the anterior border of the ramus and distal side of the second molar is less than the mesiodistal width of the crown of the third molar.

Class III : The third molar totally embedded in the bone from the ascending ramus because of the absolute lack of space.

FACTOR RESPONSIBLE FOR INCREASING THE DIFFICULTYSCORE FOR REMOVAL OF IMPACTED TEETH

•As per the angulation

•As per the depth

• As per the space available for the eruption

• Configuration of the roots of the impacted tooth

Length of the root – longer = difficulty

Root development – less than 1/3 = difficulty

Curvature of the root – dilacerated, curved,

divergent =

difficulty

Root size – thin, slender roots, stout, bulbous,

hypercementosis roots

• Bone texture and density – depend on age, sex, &

systemic problem

Younger pt. = spongy, elastic, pliable bone

Older pt. = sclerosed bone

•Size of the follicular sac – large = easier

small = difficult

• Space or contact in relation to mandibular second molar

• Relation to the inferior alveolar neurovascular bundle

• Nature of covering tissue :

Soft tissue impaction

Partial bony impaction

Fully bony impaction

• Access to the operative field, inability to open mouth wide, large uncontrolled

tongue, small orbicularis muscle.

RADIOLOGICAL EXAMINATION

Intraoral X-ray

• Possible if tooth in the alveolus not in the ramus• Possible if oral opening is adequate• If no gagging• Useful to study the configuration of the roots and status of the crown.• Useful to record the relationship with inferior alveolar canal

Three imaginary line are drawn which are known as Winter’s line

White line – The line is drawn touching the occlusal surface of Ist & IInd molar and is extended posteriorly distal to IIIrd molar or to the ramus. Amber line - The line is drawn from the crest of the interdental septum B/W the molar & extended posteriorly distal to IIIrd molar or to ramus. Red line – Is drawn perpendicular from the amber line to an imaginary point of application of the elevator. Its indicate the bone removal.

Extraoral radiograph

For mandibular teeth For maxillary teeth

>OPG > OPG

>Lateral oblique view mandible > PA view water’ position

Lateral oblique view mandible

OPG

SURGICAL REMOVAL OF IMPACTED TEETH

Asepsis and isolation

Local anaesthesia / sedation + LA / general anaesthesia

Incision – flap design

Reflection of mucoperiosteal flap

Bone removal

Sectioning ( division ) of tooth

Elevation

Debridement and smoothing of bone

Control of bleeding

Closure – suturing

Medication – Antibiotic , Analgesic , etc.

Follow - up

Isolation of Surgical site

• Scrubbing + painting of oral mucosa.

• Scrubbing solutions used first on skin only Cetrimide + absolute alcohol or cetrimide + povidone + iodine Cetrimide + absolute alcohol + chlorhexidine

• Cleaninig solution used on skin only to remove residual soap solution Normal saline Alcohol – spirit

• Painting solution – act topically to inhibit further growth of microbes chlorhexidine gluconate – 7.5% for skin , 0.2 % for oral cavity

• Drape the patient with sterile drapes to cover upper part of the face to isolate the oral cavity

Local anaesthesia

• For mandibular molar and canine pterygomandibular nerve block

• For maxillary molar PSA Palatine nerve block infiltration

• For maxillary canine Infraorbital nerve block Palatine infiltration of incisive canal Bilateral palatine nerve blocks

Incision ( Flap Design )

The incision for this mucoperiosteal flap will have a anterior limb and posterior limb connected with or without an intermediate limb

For Mandibular Molar

Anterior releasing incision begin from the vestibule upwards towards midway of the CEJ of the IInd molar at an angle. If IIIrd molar is deep and surgery requires more removal of bone, the incision should be placed anterior to the Iind molar.

The incision is then continues in the gingival sulcus ( over the alveolar crest if tooth is fully embedded ) up to the distal aspect of the IIIrd molar.

Distal releasing incision should started from distal most point of the third molar across external oblique ridge into the buccal mucosa .

• The sharp point periosteal elevator is used to carefully elevate a muco- periosteal flap beginning at the point of the incision behind the IInd molar.

•The elevator is brought forward to elevate the periosteum around the Iind molar and down the releasing incision.

• The other flatter end of the periosteal elevator is then used to elevate the posteriorly to the ascending ramus of the mandible.

1. Vertical mucoperiosteal flap design 2. An envelope flap design

Bone Removal

Aim

To exposed the crown by removing the bone overlying it To remove the bone obstructing the pathway for removal of the tooth

Two Ways Of Bone Removal

High speed, High torque handpiece and bur technique

Chisel and mallet technique

Bur technique

7/8 round bur or a straight no. 703 fissure bur is used.

Bur should always used with copious saline irrigation to avoid thermal trauma.

First step The bur is used in sweeping motion around the III molar crown except lingual aspect to expose it. Second step Once the crown has been located, the buccal surface of the tooth is exposed with the bur to the cervical level of the contour & a buccal trough or gutter is created. The bone removal around the crown is done till CEJ and the expose the crown beyond the greatest width.

Precaution while drilling the bone

Protect the overlaying tissue by retraction with either periosteal elevator or Langenbeck retractor .

Continuous irrigation to reduced thermal necrosis of the bone.

Chisel and mallet technique

•Historical important •Very rarely used•Less bone necrosis than bur technique•Can cause inadvertent fracture of the bone•The jaw bone should be supported, while using this technique.

First step For mandible and maxillary molar, placement of vertical stop cut, which is made by placing a 3 or 5 mm chisel vertically at the distal aspect of the IInd molar with facing posteriorly ( 5 to 6 mm height ).

Second step• At the base of the vertical stop cut, the chisel is placed an angle of 45 degree with

the bevel facing upwards or occlusaly, and oblique cut is made till the distal most point of third molar. This will removal of triangular piece of buccal plate distal to second molar • Additional triangular piece of bone is removed at the junction of vertical and

oblique bone cut to gain the entry of the elevator tip. Finally distal bone must be removed

Tooth sectioning, Elevation and Extraction

Reduce the amount of bone removal. Reduces the risk of damaging the neighbouring teeth. The direction of sectioning depends on the angulation of impacted tooth. Can be performed either with a bur or chisel. The tooth is usually sectioned ½ to ¾ with the bur then completely sectioned with the elevator.

Mesioangular Impaction

• Distal half of the crown is sectioned off from buccal groove till the CEJ.• A straight elevator is placed in the cut and rotated to fracture the distal portion of the crown which is removed.• Then a straight elevator is placed on the mesial aspect of III molar below the cervical area.• If the access to the elevator is not possible then a cryer or crane pick elevator can be used to elevate the tooth.

Distoangular Impaction

• Most difficult.• Large amount of distal bone removal is required.• The crown is sectioned from the roots just above the cervical line after sufficient bone is removed from the occlusal and distobuccal aspect.• The entire crown is removed to improve the visibility and access to the roots.• If the roots are divergent they are further sectioned into two pieces and delivered individually.

1. Horizontal 2. Mesioangular 3. vertically 4. distolingual

Elevation Coupland elevator – placed at the base of the crown. Winter’s cryer – may be used in wedging action/buccal elevation.

Debridement and Smoothening of Bone Margins• Irrigation of the socket.• Curettage to remove any remnants.• Look for pieces of coronal portion, granulation tissue, bleeding points.• Round off the margins of the socket with bone file.• Irrigate the socket again.• Control bleeding after suturing.

Closure• 3-0 black silk is used.• Interrupted suture given and maintained for 7 days.• In case of molars, suture distal to second molar should be placed first and should be water tight to prevent pocket formation.• In case of palatally impacted canines, incisive papilla should be sutured carefully.

COMPLICATIONS

During incision For molars - facial vessels or buccal vessels may be cut.For lower canine – mental vessel may be damaged.For upper canine - incisive canal or greater palatine vessel may be damaged.

During Bone RemovalDamage to the II molar, damage to the roots of overlying teeth, damage to thesoft tissue, fracture of the mandible when using chisel and mallet.

During elevation

• Luxation of neighbouring tooth• Fracture of adjoining bone• Fracture of the tuberosity• slipping of the tooth into pterigomandibular / temporal spaces, sub lingual pouch and maxillary sinus• Damage to nasal wall / overlying teeth / lingual, inferior alveolar or mental nerve

Intraoperative complication

During debridement

• Damage to inferior alveolar nerve / lingual nerve.• Damage the maxillary sinus

Postoperative complication

• Pain, swelling, trismus, hypoesthesia, sensivity, loss of vitality of neighbouring tooth.

• Pocket formation, sinus track formation, oroantral fistula, ornasal fistula.

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