Tooth impaction

# Overview
Tooth impaction can be defined as the interosseous position of the tooth which is completely or partially covered by mucosa and bone for more than 2 years following physiological eruption time. It can be readily confused with embedded and/or displaced teeth. Impacted teeth result from a situation in which an unerupted tooth is wedged against another tooth or teeth or located in a place where it cannot be erupted normally due to the palatal displacement. In contrast, an embedded tooth is an unerupted tooth that is covered usually completely with bone due to the lack of eruptive forces. The prevalent order of frequency of tooth impaction in the clinical practice includes mandibular and maxillary third molars, maxillary canines, mandibular premolars, mandibular canines, maxillary premolars, maxillary central incisors, maxillary lateral incisors, and mandibular second molars. Mandibular third molars are the most commonly found unerupted teeth, while maxillary third molars is the second most common. A diagnosis of impacted teeth is based on clinical symptoms, physical and radiographical examinations done by panoramic, occlusal, and periapical radiographs including cone-beam CT (CBCT) scans. The treatment plan should be based on clinical symptoms, location of the teeth, and a comprehensive examination of the impact of these teeth on neighboring teeth. Good orthodontic mechanics, surgical planning, and patient education are the mainstay of treatment. Surgical planning includes local anatomic concerns, anesthesia method, flap design, bone removal/coronal exposure, surgical instrumentation, bonding material characteristics, tooth ankylosis, and minimization of surgical complications. Additionally, all the potential complications should be explained to the patients before planned surgical and orthodontic interventions which might be sensory nerve damage leading to paresthesia, dry socket, infection, hemorrhage, bone loss, root resorption, and gingival recession around the treated teeth.

# Classification
- Winters and Pell & Gregorys systems proposed classifications based on the inclinations and positions of the third molars in relation to the dental longitudinal axis, occlusal plane, and ascending mandibular ramus.
Table 1: Winters and Pell & Gregorys criteria 

# Pathophysiology
- Normal physiological process: Tooth eruption process involves complex interaction between osteoblasts, osteoclasts and dental follicular cell lines associated with the tooth germ which result in coordinated alveolar bone resorption and emergence of tooth within the oral cavity. Moreover, the normal development of the occlusion and craniofacial complex is largely dependent on the normal physiological eruption of teeth. Therefore, an eruption is the process by which a tooth moves axially from its follicle position in the bone into its final functional position in the oral cavity. Following clinical and radiographic assessment, if a tooth is not expected to erupt due to various underlying etiologies; it results in an impacted tooth which can be classified as entirely or partially unerupted teeth.   
- Pathological factors: Teeth may fail to erupt due to the lack of space, mechanical obstruction (idiopathic or pathological origin) or disruption to the eruptive mechanism itself. The most common impacted teeth are the third molars (wisdom teeth) as they are the last to erupt due to the inadequate space between the distal of the second mandibular molar and the anterior border of the ascending ramus of the mandible. In addition to it, dental caries and endodontic illnesses are more frequently observed in comparison to entirely unerupted teeth due to difficulties in reaching partially erupted teeth during oral hygiene. 
- Ectopic tooth eruption: An impacted tooth is unable to fully erupt in its proper location because it is blocked by tissue, bone, or another tooth. However, sometimes an impacted tooth manages to erupt in the position of another tooth and causes developmental disturbance in the eruption pattern of permanent dentition. A tooth that erupts in this manner is called ectopic teeth which are displaced or incorrectly positioned. It is frequently caused by trauma, larger width of the permanent tooth, abnormal angulation of eruption of a molar, or delayed calcification of affected molars. The affected permanent molar may erupt at an angle to the normal eruption path, and thereby ceasing the eruption and causing the resorption of the neighboring deciduous tooth.  
- Impacted canine: Shafer et al. suggested the following sequelae for canine impaction:
Labial or lingual malpositioning of the impacted tooth,
Migration of the neighboring teeth and loss of arch length,
Internal resorption,
Dentigerous cyst formation,
External root resorption of the impacted tooth, as well as the neighboring teeth,
Infection particularly with partial eruption, and
Referred pain and combinations of the above sequelae.
- Labial or lingual malpositioning of the impacted tooth,
- Migration of the neighboring teeth and loss of arch length,
- Internal resorption,
- Dentigerous cyst formation,
- External root resorption of the impacted tooth, as well as the neighboring teeth,
- Infection particularly with partial eruption, and
- Referred pain and combinations of the above sequelae.

# Etiology
- Various etiologies in the form of eruption pathway barrier or an ectopic position of the tooth results in the cessation of tooth eruption; and can be detected clinically or radiographically are elaborated in Table 2.
Table 2: Enlist the etiologic factors causing an impacted tooth
- Impacted canines:
The exact etiology of palatally displaced maxillary canines is unknown. Jacobys study showed that 85% of palatally impacted canines had sufficient space for eruption; and only 17% of labially impacted canines had enough space. Therefore, arch length discrepancy is thought to be a primary etiologic factor for labially impacted canines. 
Two major proposed theories associated with palatally displaced maxillary canines are as follows:
 Guidance theory: It proposes that the canine erupts along the root of the lateral incisor serving as a guide, and the canine will not erupt in case of absent or malformed lateral incisor root. 
Genetic theory: Genetic factors are considered as a primary origin of palatally displaced maxillary canines including other associated dental anomalies such as missing or small lateral incisors, enamel hypoplasia, infraocclusion of primary molars, aplasia of second premolars, and small maxillary lateral incisors.
- The exact etiology of palatally displaced maxillary canines is unknown. Jacobys study showed that 85% of palatally impacted canines had sufficient space for eruption; and only 17% of labially impacted canines had enough space. Therefore, arch length discrepancy is thought to be a primary etiologic factor for labially impacted canines. 
- Two major proposed theories associated with palatally displaced maxillary canines are as follows:
 Guidance theory: It proposes that the canine erupts along the root of the lateral incisor serving as a guide, and the canine will not erupt in case of absent or malformed lateral incisor root. 
Genetic theory: Genetic factors are considered as a primary origin of palatally displaced maxillary canines including other associated dental anomalies such as missing or small lateral incisors, enamel hypoplasia, infraocclusion of primary molars, aplasia of second premolars, and small maxillary lateral incisors.
- Guidance theory: It proposes that the canine erupts along the root of the lateral incisor serving as a guide, and the canine will not erupt in case of absent or malformed lateral incisor root. 
- Genetic theory: Genetic factors are considered as a primary origin of palatally displaced maxillary canines including other associated dental anomalies such as missing or small lateral incisors, enamel hypoplasia, infraocclusion of primary molars, aplasia of second premolars, and small maxillary lateral incisors.
- Second molar: Andreasen and Kurol has classified the failure of the second molar eruption into three events etiologically, clinically and radiographically as explained in Table 3.
Table 3: Events resulting in the failure of the second molar eruption

# Differentiating Tooth Impaction from other Diseases
Table 4: Enlist the differential diagnosis for tooth impaction

# Epidemiology and Demographics
- Impacted molars:
Mandibular third molars (wisdom tooth) is the most commonly found unerupted teeth, while maxillary third molars are second most common.
They have been more commonly found in the unilateral form than the bilateral; and more frequently seen in the mandible than the maxilla. 
Prevalence: The incidence of impacted wisdom teeth is high with about 73% of the young adults in Europe which usually erupts between the ages of 17 and 21 years; and 72% of Swedish people aged 20 to 30 years having at least one impacted wisdom tooth.   
Race predisposition: It has been reported that the third molar eruption varies with races; such as, in Nigeria mandibular third molars may erupt as early as 14 years; and in Europe it may erupt up to the age of 26 years. 
- Mandibular third molars (wisdom tooth) is the most commonly found unerupted teeth, while maxillary third molars are second most common.
- They have been more commonly found in the unilateral form than the bilateral; and more frequently seen in the mandible than the maxilla. 
- Prevalence: The incidence of impacted wisdom teeth is high with about 73% of the young adults in Europe which usually erupts between the ages of 17 and 21 years; and 72% of Swedish people aged 20 to 30 years having at least one impacted wisdom tooth.   
- Race predisposition: It has been reported that the third molar eruption varies with races; such as, in Nigeria mandibular third molars may erupt as early as 14 years; and in Europe it may erupt up to the age of 26 years. 
- The impaction of other permanent teeth is also frequently reported with a prevalence ranging from 2.9% to 13.7%. The most commonly impacted teeth are the canines and second premolars in both jaws with different incidence rates.  
- Impacted canines:
Maxillary canines are the most commonly impacted teeth, second only to third molars. 
 Gender predilection: It is twice as common in females than males.
 Prevalence: Maxillary canine impaction occurs in approximately 2% of the population, and it's incidence in the maxilla is more than twice that of the mandible.
Laterality: About 8% have bilateral impacted maxillary canines. 
 Location: Approximately one-third of impacted maxillary canines are located labially and two-thirds are located palatally. 
- Maxillary canines are the most commonly impacted teeth, second only to third molars. 
- Gender predilection: It is twice as common in females than males.
- Prevalence: Maxillary canine impaction occurs in approximately 2% of the population, and it's incidence in the maxilla is more than twice that of the mandible.
- Laterality: About 8% have bilateral impacted maxillary canines. 
- Location: Approximately one-third of impacted maxillary canines are located labially and two-thirds are located palatally. 

# Risk Factors
- Age: An angle of the impacted tooth might increase in severity as the age progresses; and hence, an early diagnosis and treatment are recommended especially for the maxillary canines.
- Gender: Females have a higher predisposition to suffer from more severe teeth impaction especially of the maxillary canines because it is proposed that teeth erupt a little earlier in females than males. Thus, it is advised to diagnose impaction in females at an earlier stage to carry out any necessary preventive or interceptive orthodontic procedures.
- Microdontia: The maxillary lateral incisor microdontia is significantly associated with more severe tooth impaction, and emphasizes the tooth size investigations in patients especially with small laterals.
- Modern diet: It tends to be softer and does not offer a decided effort in mastication which subsequently results in the loss of growth stimulation of jaws and higher susceptibility of developing impacted and unerupted teeth. In addition to it, artificial feeding of babies and more consumption of sweet food by the children and youth further produces disproportion in the jaws and thus an impacted tooth.

# Natural history and Prognosis
- Whether the surgical removal of impacted tooth is for prophylactic, orthodontic and prosthetic reasons or for the diagnosis of several associated pathologies, it is one of the most performed dentoalveolar procedures in oral and maxillofacial surgery. In the United States, approximately 3 billion dollars are spent yearly on the extraction of impacted third molars. 
- However, the surgical removal might present with the complications in up to 15% of cases such as nerve injuries, post-operative infections, and iatrogenic mandibular fractures.
- Hence, the surgical interventions among asymptomatic cases should weigh the risks of removal and benefits of tooth preservation.

# Complications

## Pericoronitis
- Pericoronitis: It is an inflammatory condition involving the soft tissue around a vertically positioned partially erupted third molar at or near the level of the occlusal plane; and among orthodontically treated cases with mesioangular position of the lower third molars. Similarly, the eruption process also causes minor gingivitis; and its symptoms may coincides with pericoronitis which creates the diagnosis issues for the dentists when it comes to lower impacted third molars.
- Clinical signs and symptoms: The gingival tissues may be exquisitely tender and purulent causing significant discomfort and limits the jaw opening and chewing function. Most commonly, it presents with an acute and recurrent presentation; however, in some cases it may be chronic and painless with only intermittent symptoms. 
- Treatment:
It is managed by the subgingival curettage to remove the plaque and foreign bodies followed by an irrigation with antimicrobials such as chlorhexidine or antibiotic therapy.
In cases where the erupted or partially erupted upper third molar impinges on a lower operculum, extraction of the upper third molar may aid pain control and speed the healing process.
Extraction of the lower third molar tooth is advised once infection and swelling have resolved, especially in the recurrent cases.
- It is managed by the subgingival curettage to remove the plaque and foreign bodies followed by an irrigation with antimicrobials such as chlorhexidine or antibiotic therapy.
- In cases where the erupted or partially erupted upper third molar impinges on a lower operculum, extraction of the upper third molar may aid pain control and speed the healing process.
- Extraction of the lower third molar tooth is advised once infection and swelling have resolved, especially in the recurrent cases.

## Dental caries
- It is the most common hard-tissue disorder associated with third molar teeth.
- Risk factors: Its prevalence appears to increase over time due to the malposition of teeth which might never achieve complete eruption; and thus, making it difficult for dental restoration. 
- Treatment: Extraction is considered as the most efficacious treatment which involves an impacted third molar itself and/or the distal surface of the second molar in cases with third molar angulation. 

## Odontogenic cysts and tumors
- Impacted teeth were found associated with lesions such as dentigerous cysts, unicystic ameloblastomas, ameloblastomas, ameloblastic fibromas, calcifying odontogenic cysts, adenomatoid odontogenic tumors, calcifying epithelial odontogenic tumors, ameloblastic fibroodontomas, keratocystic odontogenic tumors, central giant cell granuloma, odontomas, etc. 
- Dentigerous cyst, unicystic ameloblastoma, ameloblastoma, and ameloblastic fibroma are most frequent with the mandibular third molar teeth. 
- The incidence of large cysts and tumors occurring around impacted third molars is relatively rare showing a wide range from 0.001% on a biopsy to 11% when the diagnosis was clinically established. This wide variation indicates that the presence of a cyst is a weak indication for prophylactic extraction of impacted third molars.
- However, in some cases the presence of odontogenic cysts and tumors in the third molar region can cause severe consequences such as pathological mandibular fracture and facial asymmetry. Hence, the surgical interventions among asymptomatic cases should weigh the risks of removal and benefits of tooth preservation.

## Periodontitis
- Asymptomatic third molar teeth, especially lower third molar teeth, are frequently associated with pathologic periodontal conditions. The gingivae around these teeth harbor bacteria which serves as a reservoir for the development of the generalized periodontal disease. 
- The incidence of periodontitis has been reported to vary from 1% to 5% on the distal surface of the second molar which increases with age irrespective of the presence or absence of the third molars; and thus, a higher incidence of periodontitis has been observed among the older patients in relation to the impacted wisdom teeth. 
- Treatment: A periodontal probing should be an integral part of clinical assessment to adequately advise the patient about retention or extraction of third molars. However, the removal of third molars reduces the presence of periodontopathic bacteria at second molar sites and thus, further prevent or delay the onset of adult periodontitis. 

## Root resorption
- It has been found that an impacted third molar left in-situ may cause resorption of the distal root of the adjacent second molar.
- Some studies have also reported an association between root resorption at the apex and increasing age.

## Miscellaneous
- Pain: It is the one of the most commonly reported complaint associated with impacted third molar whose prevalence varies greatly from 5% to 53%.
- Cellulitis and osteomyelitis: Its incidence has been reported to be around 5%.
- Others: Functional disorders such as occlusal interference, cheek biting, mastication disorders, trismus and temporomandibular joint problems. 

# Diagnosis
- Impacted teeth may remain asymptomatic and be incidentally diagnosed by routine dental radiography.
- It may be diagnosed via symptoms such as pressure, pain, or swelling; by physical examination with probing or direct visualization; or various associated pathologies such as caries, pericoronitis, cysts, tumors, and root resorption of the adjacent tooth.
- Clinical signs and symptoms: Caries, pain, swelling, paresthesia, periodontal pocket and pericoronitis.
- Physical exam: Inspection and palpation of the temporomandibular joint and movement of the mandible, determination of mobility characteristics of lips and cheeks, size and contours of the tongue, and appearance of soft tissue overlying the impacted teeth.
Impacted canine: Following clinical signs might be indicative of canine impaction:
Delayed eruption of the permanent canine or prolonged retention of the deciduous canine beyond 1415 years of age
Absence of a normal labial canine bulge
Presence of a palatal bulge and
Delayed eruption, distal tipping, or migration (splaying) of the lateral incisor
- Impacted canine: Following clinical signs might be indicative of canine impaction:
Delayed eruption of the permanent canine or prolonged retention of the deciduous canine beyond 1415 years of age
Absence of a normal labial canine bulge
Presence of a palatal bulge and
Delayed eruption, distal tipping, or migration (splaying) of the lateral incisor
- Delayed eruption of the permanent canine or prolonged retention of the deciduous canine beyond 1415 years of age
- Absence of a normal labial canine bulge
- Presence of a palatal bulge and
- Delayed eruption, distal tipping, or migration (splaying) of the lateral incisor
- Radiographic evaluation: The most common radiographic methods in the diagnosis of tooth impaction are periapical or panoramic radiographs (OPG) which assess the root morphology, size of follicular sac, density of the surrounding bone, contact with the second molar, nature of overlying tissues, inferior alveolar nerve and vessels, relationship to body and ramus of mandible, relation with adjacent teeth and buccal to lingual position of the third molar. Source: Case courtesy of Dr Bruno Di Muzio, Radiopaedia.org, rID: 55220
Impacted canine: Several radiographic exposures including occlusal films, panoramic views, and lateral cephalograms can help in evaluating the position of the canines; however, periapical films are considered most reliable in such cases.   
Periapical films: It provides the clinician with a two-dimensional representation of the dentition and relates the canine to the neighboring teeth both mesiodistally and superoinferiorly. To evaluate the position of the canine buccolingually, a second periapical film should be obtained by the Tube-shift technique or Clarks rule or (SLOB) or Buccal-object rule.
Occlusal films: It helps to determine the buccolingual position of the impacted canine in conjunction with the periapical films provided that the image of the impacted canine is not superimposed on the other teeth.
Extraoral films:
Frontal and lateral cephalograms: These helps in determining the position of the impacted canine and its relationship with other facial structures such as the maxillary sinus and the floor of the nose.
Panoramic films: These are employed as the primary imaging technique for the evaluation of impacted teeth and involved lesions in all the three planes of space and thus, helpful for diagnosis, followup of tooth eruption, and treatment results. It is quite similar to the two periapical films in the tube-shift method with the source of radiation coming from behind the patient; and thus, the movements are reversed for the position. 
Cone beam computed tomography (CBCT): It provides precise and accurate information better than conventional radiographs in terms of relation of the impacted tooth with the adjacent tooth, nasal floor, maxillary sinus, and mandibular canal in three dimensions. However, increased cost, time, radiation exposure, and medicolegal issues associated with using CBCT limit its routine use.  Source: Case courtesy of Dr Matthew Lukies, Radiopaedia.org, rID: 46588
- Impacted canine: Several radiographic exposures including occlusal films, panoramic views, and lateral cephalograms can help in evaluating the position of the canines; however, periapical films are considered most reliable in such cases.   
Periapical films: It provides the clinician with a two-dimensional representation of the dentition and relates the canine to the neighboring teeth both mesiodistally and superoinferiorly. To evaluate the position of the canine buccolingually, a second periapical film should be obtained by the Tube-shift technique or Clarks rule or (SLOB) or Buccal-object rule.
Occlusal films: It helps to determine the buccolingual position of the impacted canine in conjunction with the periapical films provided that the image of the impacted canine is not superimposed on the other teeth.
Extraoral films:
Frontal and lateral cephalograms: These helps in determining the position of the impacted canine and its relationship with other facial structures such as the maxillary sinus and the floor of the nose.
Panoramic films: These are employed as the primary imaging technique for the evaluation of impacted teeth and involved lesions in all the three planes of space and thus, helpful for diagnosis, followup of tooth eruption, and treatment results. It is quite similar to the two periapical films in the tube-shift method with the source of radiation coming from behind the patient; and thus, the movements are reversed for the position. 
Cone beam computed tomography (CBCT): It provides precise and accurate information better than conventional radiographs in terms of relation of the impacted tooth with the adjacent tooth, nasal floor, maxillary sinus, and mandibular canal in three dimensions. However, increased cost, time, radiation exposure, and medicolegal issues associated with using CBCT limit its routine use.  Source: Case courtesy of Dr Matthew Lukies, Radiopaedia.org, rID: 46588
- Periapical films: It provides the clinician with a two-dimensional representation of the dentition and relates the canine to the neighboring teeth both mesiodistally and superoinferiorly. To evaluate the position of the canine buccolingually, a second periapical film should be obtained by the Tube-shift technique or Clarks rule or (SLOB) or Buccal-object rule.
- Occlusal films: It helps to determine the buccolingual position of the impacted canine in conjunction with the periapical films provided that the image of the impacted canine is not superimposed on the other teeth.
- Extraoral films:
Frontal and lateral cephalograms: These helps in determining the position of the impacted canine and its relationship with other facial structures such as the maxillary sinus and the floor of the nose.
Panoramic films: These are employed as the primary imaging technique for the evaluation of impacted teeth and involved lesions in all the three planes of space and thus, helpful for diagnosis, followup of tooth eruption, and treatment results. It is quite similar to the two periapical films in the tube-shift method with the source of radiation coming from behind the patient; and thus, the movements are reversed for the position. 
Cone beam computed tomography (CBCT): It provides precise and accurate information better than conventional radiographs in terms of relation of the impacted tooth with the adjacent tooth, nasal floor, maxillary sinus, and mandibular canal in three dimensions. However, increased cost, time, radiation exposure, and medicolegal issues associated with using CBCT limit its routine use.  Source: Case courtesy of Dr Matthew Lukies, Radiopaedia.org, rID: 46588
- Frontal and lateral cephalograms: These helps in determining the position of the impacted canine and its relationship with other facial structures such as the maxillary sinus and the floor of the nose.
- Panoramic films: These are employed as the primary imaging technique for the evaluation of impacted teeth and involved lesions in all the three planes of space and thus, helpful for diagnosis, followup of tooth eruption, and treatment results. It is quite similar to the two periapical films in the tube-shift method with the source of radiation coming from behind the patient; and thus, the movements are reversed for the position. 
- Cone beam computed tomography (CBCT): It provides precise and accurate information better than conventional radiographs in terms of relation of the impacted tooth with the adjacent tooth, nasal floor, maxillary sinus, and mandibular canal in three dimensions. However, increased cost, time, radiation exposure, and medicolegal issues associated with using CBCT limit its routine use.  Source: Case courtesy of Dr Matthew Lukies, Radiopaedia.org, rID: 46588
- Radiological changes:
Noninflammatory: Caries; Root resorption (internal or external); Interdental bone loss; Hyperplastic dental follicle
Mild inflammatory: Pericoronal radiolucent areas suggesting pericoronitis; Periapical radiolucent areas suggesting abscess
Severe inflammatory: Osteomyelitis
- Noninflammatory: Caries; Root resorption (internal or external); Interdental bone loss; Hyperplastic dental follicle
- Mild inflammatory: Pericoronal radiolucent areas suggesting pericoronitis; Periapical radiolucent areas suggesting abscess
- Severe inflammatory: Osteomyelitis

# Treatment
- The management plan is based upon the presenting complaint and the history of the patient, the physical evaluation, radiographic assessment, the diagnosis, and the prognosis, which can be decided on the basis of etiology as a following: 
Impaction: An early removal of physical barrier improves the chances of spontaneous eruption followed by orthodontic up righting if required.
Primary retention: Unerupted tooth can be surgically repositioned following segment alveolar osteotomy. An involved teeth tend to ankylose if orthodontic force is applied. Prosthetic replacement of missing and unerupted tooth is the last resort. 
Secondary retention: An immediate removal of affected molar followed by orthodontic alignment of neighboring teeth can be done in case secondary retention develops prior to growth spurt. An exposed tooth may be luxated to promotes eruption. Autotransplantation of third molar into the space created by missing teeth can be done.
- Impaction: An early removal of physical barrier improves the chances of spontaneous eruption followed by orthodontic up righting if required.
- Primary retention: Unerupted tooth can be surgically repositioned following segment alveolar osteotomy. An involved teeth tend to ankylose if orthodontic force is applied. Prosthetic replacement of missing and unerupted tooth is the last resort. 
- Secondary retention: An immediate removal of affected molar followed by orthodontic alignment of neighboring teeth can be done in case secondary retention develops prior to growth spurt. An exposed tooth may be luxated to promotes eruption. Autotransplantation of third molar into the space created by missing teeth can be done.
- Treatment difficulty index predicts an earlier the diagnosis and treatment of the impacted tooth, the less complicated and shorter the treatment duration; and further suggests that a severely impacted tooth can migrate and cross the midline with time indicating importance of an early diagnosis and treatment planning.
- The higher the rank of the position of the impacted tooth, the more difficult it is to align.

## Modes of treatment
- Observation:
A longterm observation is recommended in an impacted mandibular the third molar embedded in bone with no perceptible to the follicle which might be seen in an older individual with no history and signs of associated pathology.
Most impacted teeth retain an erupting potential, and annual/biannual evaluation would be recommended if no indications for direct surgical management seen.
- A longterm observation is recommended in an impacted mandibular the third molar embedded in bone with no perceptible to the follicle which might be seen in an older individual with no history and signs of associated pathology.
- Most impacted teeth retain an erupting potential, and annual/biannual evaluation would be recommended if no indications for direct surgical management seen.
- Exposure: It is considered if the probability of eruption into useful occlusion is higher but obstructed by follicle, sclerotic bone, hypertrophic soft tissue, or odontoma. An exposure of a blocked third molar may be considered in absent second molar cases.
- Transplantation of a mandibular third molar: The variety of crown and root shape on the impacted third molar make them suitable for transplantation to other molar sites, bicuspid and even the cuspid locations depending on the anatomy of the coronal and radicular surface.
- Removal: The primary reason to remove a tooth is to correct associated pathology and to intercept reasonably expected pathological process. There are 3 main surgical options in the management of impacted teeth:  
Extraction of an impacted tooth
Extraction of an adjacent tooth
Non-extraction treatment: It involves an orthodontic space opening in order to align the teeth, to open the space for the impacted tooth and to enhance the natural eruption process followed by the surgical exposure.
- Extraction of an impacted tooth
- Extraction of an adjacent tooth
- Non-extraction treatment: It involves an orthodontic space opening in order to align the teeth, to open the space for the impacted tooth and to enhance the natural eruption process followed by the surgical exposure.

## Indications for Mandibular Third Molar Extraction
- Various conditions are indications for the removal of impacted third molars which are as follows in Table 5:
Table 5: List of indications for impacted tooth extraction

## Impacted canine
- The management of impacted canines is important in terms of esthetics, function, and to reduce the frequency of ectopic eruption with subsequent impaction of the maxillary canine.
- Firstly, the simplest interceptive procedure to prevent impaction of permanent canines in the early diagnosis and timely extraction of the primary canines which allows the permanent canines to become upright and erupt properly into the dental arch provided sufficient space is available to accommodate them.
- Secondly, in the absence of prevention, dentists should consider orthodontic treatment followed by surgical exposure of the canine to bring it into occlusion. The most common methods used to bring palatally impacted canines into occlusion are surgically exposing the teeth and allowing them to erupt naturally during early or late mixed dentition and surgically exposing the teeth and placing a bonded attachment to and using orthodontic forces to move the tooth. 
- Orthodontists have recommended to first create adequate space in the dental arch to accommodate the impacted canine and then surgically expose the tooth to give them access so that they can apply mechanical force to erupt the tooth.
- The most efficient way to make impacted canines erupt is to use closed-coil springs with eyelets as long as no obstacles impede the path of the canine.
- Orthodontists may consider treatment alternatives such as autotransplantation or restoration in collaboration with other specialists such as oral surgeons, periodontists, and prosthodontists.

## Post extraction risks and complications
- Several local and general factors which include tooth position, age of the patient, health status, knowledge and experience of the dental surgeon, and surgical equipment used can lead to the various post-extraction risks and complications enlisted in the following Table 6:
Table 6: Enlists post extraction risks and complications