Surgical management of Unerupted and Impacted teeth

Terminology

• Unerupted tooth (retained tooth): is that fail to erupt into the oral cavity at the normal time and age.
• Impacted tooth: is a retained tooth that is completely or partially buried in the soft tissue or the bone.
• Aberration: is a tooth that develop distant from its normal location. 
• Ectopic eruption: eruption of a tooth outside the arch line based on clinical evaluation.
• Agenesis: failure of a tooth to develop due to many reasons and genetic factor is highly contributed.

 Common unerupted and impacted teeth:

1. Mandibular third molars
2. Maxillary canines
3. Mandibular second premolars
4. Maxillary second premolar
5.  Mandibular canines

Etiology of failure of eruption

1. Tooth agenesis.
2. Injury to tooth germ and displacement of tooth follicle.
3. Crowding and disproportion between teeth size and jaw.
4. Premature loss of a deciduous predecessor and gingival fibromatosis
5. Presence of supernumerary teeth
6. Presence of tumors or cysts
7. Cleft palate and alveolus
8. Cleidocranial dysostosis
9. Conginital brevicollis dystrophy
10. Klipped feil syndrome
11. Hypopituitarism
12. Cretinism (infantile hypothyrodism)
13. Rickets

Indications-(Rational for treatment)

• Majority removed because of pain or being a foci of infection.
• Involvement in pathology like cyst and tumors.
• Resorption of roots of adjacent teeth.
• Interference in line of osteotomies and fractures.
• Infection of surrounding soft or hard tissue.
• For prophylactic reasons.

Contraindications-(Relative)

Asymptomatic unerupted teeth that removal is possibly complicated by an injury to inferior dental or lingual nerve during surgery treatment.

Teeth of favorable position that can be monitored at time intervals to detect the development of any complications.

Recognition of the problem:

The existence, position, orientation of the impaction and diagnosis of associated problems are based on:

• History
• Clinical examination
• Radiography

History

Missing tooth or teeth with or without history of pain and swelling of underlying mucosa (agenesis??)

In case of pain, effort must be paid to eliminate other possible causes of dental pain from another tooth such as pulpitis and periodontitis.

Pain at posterior aspect of the mouth that can be a refereed type of pain such as earache, eye pain, artherolgia, etc.)

Inflammation around the crown of the tooth that make more acute symptoms (pericoronitis).

Examination

• Recording of missing teeth.
• Recording of retained deciduous teeth.
• Identify caries and periodontal diseases.(pain might be from adjacent carious tooth, this would influence the proposed treatment planning)
• Vitality test of all teeth in doubt.
• Examination for sign of infection.(swelling, discharge, trismus and enlarged lymph nodes)
• Facial asymmetry and jaw bone expansion.

Radiography-(objective indications)

• To disclose the unerupted tooth and the texture of the surrounding bone.
• To disclose the position in the jaw and its relation to adjacent teeth and other vital structures (sinuses, IDC,).
• To disclose the crown-root ratio and roots configuration.
• (curvature, numbers, hypercemntosis, bulbous, fused or diverged)
• To disclose the degree and orientation of impaction.
• To disclose atrophy of dental follicles and existence of pathological development.

Preoperative assessment

Asymptomatic unerupted teeth most often discovered following radiographical screening (accidental findings).

Partially erupted teeth might be associated with pain and infection.

Impacted lower wisdom tooth may cause crowding upon anterior teeth.

Impacted tooth may erode or cause cavitation of adjacent teeth.

Impacted teeth may be associated with pathological cyst development.

Pericoronitis

• Infection involves the soft tissue surrounding the crown of partially erupted tooth.
• Usually caused by streptococci and anaerobic bacteria.
• It may presented as an acute or chronic infection.
• Acute infection developed over hours and days and associated possibly with systemic manifestation.
• Chronic infection distinguished by redness and or discharge of pus with few acute symptoms lasting over weeks to months.
• It may be associated with poor oral hygiene and upper respiratory infection.

Signs and symptoms:

• Swelling of retro-molar tissue
• Soreness
• Erythemia of overlaying soft tissue or operculum
• Trismus
• Facial swelling of the affected side
• Raised temperature
• Regional lymphodenopathy
• General malaise

Contributory factors:

• Trauma from an opposing over-erupted wisdom tooth
• Entrapment of food debris and bacterial infection under the operculum
• Physical and mental stress
• Pregnancy and suppression of the immune system
• Upper respiratory tract infection

Management of pericoronitis

1. Local irrigation by hot salt mouthwash. chlorhexidine mouthwash
2. Antibiotics if signs of spreading infection are evident. (amoxycillin, metronidazole)
3. Analgesic and non-steroidal anti-inflammatory agent.
4. Extraction of upper opposing wisdom tooth if traumatizing the lower operculum.
5. Removal of lower wisdom tooth when acute infection is resolved.
6. Hospital admission in case of severe infection that may compromise the airway.

Considerations in clinical examination of an impacted/ partially erupted tooth

1. Patient age and tooth eruption
2. Associated infection
3. Caries and restoration
4. Dental status of the adjacent tooth
5. Periodontal status
6. State of the TMJ

 Status of tooth in question

• Based on clinical evaluation
• Erupted but non-functional (no opposing, tilted, carious, etc.)
• Partially erupted (covered partially with soft tissue)
• Partially erupted with sign of recurrent infection
• Truly impacted (bony or soft tissue)
• Association with pathological lesions

Methods of radiographical examination

Radiographs in two planes at right angles are needed to show clearly the position of the tooth and the degree of impaction

• Orthopantomogram (OPG)
• Preapical radiograph
• Lateral oblique view of the jaw
• Vertex occlusal view
• Parellex method of Clark

Radiographical assessment

• Orientation (mesioangular, vertical, distoangular and transalveolar)
• Depth below the occlusal plane
• Crown size and follicular width
• Root morphology (number, length, shape: fused or separate, curved apex, bulbous, ankylosis).
• Condition of the crown and the adjacent tooth
• Approximation of an ascending ramus, IDC, maxillary sinus, ptrygoid plates and pyriform fossa.

Management of impacted/ partially erupted teeth

 

Options of management 

1. No treatment
2. Conservative management
3. Surgical repositioning and transplantation
4. Exposure of the teeth with or without orthodontic application
5. Surgical removal

No treatment-(Choices of putting tooth in probation)

• Asymptomatic tooth
• When it acts as a buttress for the root of adjacent tooth
• When vital structures are at risk of injury in the course of operation
• In case of acute preicoronitis

Conservative management

• Tooth that might be brought into occlusion provided that space is adequate in the arch line.
• When adjacent tooth is carious, heavily filled or missing.
• Mesial drifting may allow tooth to replace poorly prognosis or missing anterior one

Surgical repositioning and transplantation

• Aimed to move tooth bodily into the dental arch
• Careful surgical extraction is required to minimize the damage to the apical vessels and periodentium
• Imobilization within the prepared socket for 4 weeks
• Success determined by the dental age (unclosed apices), patient age and atrumatic surgery
• Resorption of root might be evident in 2-5 years
• Early endondontic treatment might be of help to minimize the failure

Third molar transplantation 

Surgical aids to orthodontics

• It is mostly prescribed for impacted canine
• Other teeth might be considered as well
• Aimed to help in establishing optimum occlusion orthodontically
• The canine is very important esthetically
• The success is very high
• Surgery for exposure is much easier than for removal of the impaction

Surgery-assisted orthodontic traction

• Reflection of mucoperiosteal flap
• Crown is to be freed to its greatest circumference
• Preservation of attached ginigiva for labially and buccally placed teeth
• Orthodontic device ( button, hock and ligature wire) is to be applied
• Flap is to be then sutured  back in position
• For palatal placed teeth, soft tissue excision for exposure is to be packed with whitehead’s varnish, BIPS, coepack
• Orthodontist visit to be arranged one week post op for traction application
• The procedure:

Removal of unerupted teeth

• Earlier to sclerosis of bone
• Earlier to follicle atrophy
• When it is infection-free
• Before fully development of roots
• When 2/3 of the roots are formed
• Best timing for removal

 Surgical Considerations

• Localization of unerupted tooth
• Morphology of the tooth and roots
• Relationship to the inferior dental neurovascular bundle
• Buccolingual position
• Relationship to adjacent teeth
• Relationship to inferior border of the mandible and anterior border of the ramus

Planning for operation

• “Reverse in order”
• The tooth position in jaw
• The natural line of withdrawal
• Overcome obstacles (ascending ramus and adjacent tooth or teeth)
• Point of application for elevation
• Access by removing bone and design flap accordingly

Natural line of withdrawal

Teeth extracted by moving them away from sockets or bone along their pathway

The course of movement is dictated by the curvature of the roots

Unfavorable elevation refers to tooth goes deeper in bone or impacted against another tooth

Violation of the principles of line of withdrawal

Fracture of bone (the whole entity or part of it)

Displacement of tooth into soft tissue or anatomical spaces

Damage of inferior dental nerve

 

Obstacles to elevation

Intrinsic

√ shape of the tooth and root

√ Constriction at the neck of the tooth

Extrinsic

√ bone and depth of the tooth

√ adjacent tooth (impaction against a tooth )

√ adjacent vital structures (the inferior dental neurovascular bundle)

Overcoming the obstacles

Removing sufficient bone to allow tooth to be rotated and delivered

Division of the tooth horizontally or vertically or by both using:

√ drill and large fissure bur

Removal of lingual plate using:

√ chisels and mallet

 

Point of application

Dental elevators is the best for removal of buried teeth

Point of application must be determined during planning

Point of application is to be prepared simultaneously during access preparation

No tooth division until adequate point of application has been prepared.

Preparation for surgery

Hospital and general anesthesia

Outpatient clinic with either intravenous sedation or local anesthesia

Surgical access

• Flap must be sufficient enough to allow direct vision with no chance of tension and trauma
• Bone removal should permit tooth with its greatest crown dimension to pass freely (tooth division may minimize the need for more bone removal)
• Curved and bulbous root must be made free of bone
• Cutting of bone and tooth division must be completed before attempting elevation
• Flap is to be replaced and rests on bone before suturing

Closure of wound

• Debridment and smoothening of sharp edges of the socket
• Removal of dental follicle (sack) without endangering vital structure (lingual nerve)
• Primary closure as long as flap is not under tension is desirable
• Resorbable or non-resorbable suture may be used
• Suture notes should be kept to a minimum

Surgery of Mandibular Impacted/ Parially Erupted Teeth

Position

• Vertical
• Horizontal
• Mesioangular
• Distoangular
• inverted
• Transbuccally (crown facing lingually or buccally)
• Apparent position; ramus or close to inferior border of the mandible

 

Impacted mandibular canine and premolar tooth

 

Maxillary Teeth

• Surgical considerations
• Position of unerupted tooth (3^rd molar or canine)
• Relationship to adjacent teeth
• Relationship to maxillary sinus
• Morphology of the roots
• Status of adjacent teeth
• Presence of supernumerary and supplemental teeth

Upper third molar Operative technique

• The flap
• The envelop flap
• Two sided flap (triangular type)
• Bone removal
• Establishment of OAF
• Closure

Surgical exposure and surgical removal of impacted canine and anterior

Palatally positioned tooth

Labially positioned tooth

Removal of unerupted teeth from edentulous ridge
surgical consideration

• Difficulty is owing to sclerotic bone and loss of periodontal space
• Gentle force via a well prepared point of application would minimize the risk of fracture of brittle bone
• Alveolar ridge preservation by accurate assessment and minimal bone removal
• Osteoplastic flap to preserve the alveolar bone in height and in width
• Bone reduction and fixation in the incident of atrophic jaw fracture

Difficulties-associated surgery

• Small mouth
• Narrow space between anterior border of the ramus and distal aspect of second molar tooth buried deeply in bone
• Approximation of inferior dental canal and sinuses
• Existence of fusion and ankylosis
• Devitalizations and cavitations

Complications associated with unerupted and impacted teeth surgery

Intraoperative:

√ hemorrahge

√Fractured root, tuberosity

√Damage to adjacent tooth, tooth displacement

√ oroantral-oronasal communication

√Fracture mandible

Postoperative:

√ pain, swelling, bruising, trismus, aneathesis, infection