CHAPTER II - IMPACTED TEETH (TOOTH ERUPTION (three conditions of teeth with arrestes eruption, types of eruption abnormalities), IMPACTION (theories, basic principles, incidence/frequency, etiology/causes) INDICATIONS FOR REMOVAL OF IMPACTED TEETH)

TOOTH ERUPTION

physiological process associated with root development in which the developing teeth move from their area fro formation inside the jaw into the oral cavity to become part of the dental arch

TOOTH ERUPTION

Is said to be complete well before apex closure

THREE CONDITIONS OF TEETH WITH ARRESTED ERUPTION

1. IMPACTION

2. PRIMARY RETENTION

3. SECONDARY RETENTION

IMPACTION

• cessation of the eruption of a tooth caused by a clinically or radiographically detectable physiological or physical barrier in the eruption path, or due to an abnormal tooth position

IMPACTION

• physical barrier in the eruption path usually occurs due to lack of space that arises as a result of collision between developing teeth

cysts, crowded tooth germ or erupting teeth, supernumerary teeth, & odontomas

• other barriers that may prevent eruption include:

*ODONTOMAS

• benign tumors of odontogenic origin

PRIMARY RETENTION

Cessation of eruption of a normally placed & normally developed tooth or tooth germ before gingival emergence without a recognizable physical barrier in the eruption path

PRIMARY RETENTION

Clinically manifested as a delay in tooth eruption that is > 2 years

PRIMARY RETENTION

Caused by disturbance in the dental follicle that fails to initiate the metabolic events responsible for bone resorption in the eruption trajectory

PRIMARY RETENTION

Occurs more frequently than secondary retention regardless of gender

PRIMARY RETENTION

Synonymous with the following: unerupted teeth and embedded teeth

UNERUPTED TEETH

• Refers to teeth that did not perforate the oral mucosa (with or without apex closure)

• May manifest with signs & symptoms

**NOT ALL ERUPTED TEETH ARE IMPACTED

EMBEDDED TEETH

• Pertains to individual teeth that did not erupt because of a lack of eruptive force

• Occurs without any signs & symptoms

SECONDARY RETENTION

• cessation of eruption of a tooth after gingival emergence when there is no ectopic (displaced) eruption or any physical barrier in the eruption path

SECONDARY RETENTION

• clinically manifested when the tooth does not reach the normal occlusal plane at the scheduled or expected time

SECONDARY RETENTION

• causative factors include the following:

  • Trauma

  • Infection

  • Disturbed local metabolism

  • Genetics

  • Ankylosis

*ANKYLOSIS

• anatomic fusion of cementum or dentin with the alveolar bone

SECONDARY RETENTION

Exhibited on a radiograph as resorption of the root surface or focal obliteration of the periodontal ligament space

SECONDARY RETENTION

Synonymous with the following: reimpaction, submerged teeth, and reinclusion

REIMPACTION

• defines a situation in which a tooth has completely erupted in the occlusal plane and then it is submerged again into the alveolar bone, producing the clinical aspect of infraocclusion

*INFRAOCCLUSION

Clinical term that describes a tooth that is situated below the normal occlusal plane following partial eruption or reimpaction

SUBMERGED TEETH

• refers to teeth that have undergone root resorption & are ankylosed to the alveolar bone after gingival emergence

SUBMERGED TEETH

Occlusal surface of the tooth lies above the gingiva, but below the occlusal plane of the remaining teeth or adjacent teeth

REINCLUSION

• inability of a tooth to maintain the continuous eruptive potential as the jaws grow

*TREATMENT FOR THESE CONDITIONS (Reimpaction, Submerged Teeth, Reinclusion)

• interventional approach & reverting the disorder back to normal

• Example would include the following:

  • Orthodontic correction

  • Space augmentation

  • Removal of the physical barrier in the eruption plane

  • Surgical modalities

TYPES OF ERUPTION ABNORMALITIES

1. PREMATURE ERUPTION

2. DELAYED ERUPTION

3. EMBEDDED TOOTH

4. ERUPTION SEQUESTRUM

5. IMPACTED TOOTH

PREMATURE ERUPTION

• situation when a tooth erupts into the oral cavity much before the normal time of eruption

PREMATURE ERUPTION

• Involves only 1-2 teeth (most commonly the primary mandibular central incisors)

PREMATURE ERUPTION

• Not considered as supernumerary teeth and should be preserved in the mouth if possible

TYPES OF PREMATURE ERUPTION

A) NATAL TEETH

B) NEONATAL TEETH

NATAL TEETH

Erupted primary teeth that are present at birth

NEONATAL TEETH

Primary teeth that erupt during the 1st 30 days of life (1st month)

DELAYED ERUPTION

Refers to the 1st appearance of teeth in the oral cavity at a much later time than what is normally expected

EMBEDDED TOOTH

An individual tooth that fails to erupt for no apparent cause & without any signs or symptoms

EMBEDDED TOOTH

Tooth lied just below the gum line

ERUPTION SEQUESTRUM

A small fragment of necrosed bone, which sometimes seen overlying an erupting tooth

ERUPTION SEQUESTRUM

Caused by the lack of complete resorption of the overlying alveolar bone during eruption

ERUPTION SEQUESTRUM

Clinically it may cause pain, soreness, & difficulty in mastication

IMPACTED TOOTH

Refers to a tooth that is prevented from completely erupting into a normal functional position due to lack of space, obstruction by another tooth, or an abnormal eruption path

IMPACTED TOOTH

• can occur with any tooth (which may either be completely unerupted or partially unerupted) that does not reach its normal position in the mouth because it is positioned against another tooth, bone, or soft tissue/s; and it will not eventually assume a normal arch relationship with the other teeth & tissue/s

IMPACTED TOOTH

• any tooth that has failed to fully erupt into the oral cavity within its expected developmental time period & can no longer reasonably be expected to do so

THEORIES OF IMPACTION (By Durbeck)

1. ORTHODONTIC THEORY

2. PHYLOGENIC THEORY

3. MENDELIAN THEORY

4. PATHOLOGICAL THEORY

5. ENDOCRINAL THEORY

ORTHODONTIC THEORY

states that in as much as the normal growth of the jaw & the movement of the teeth are in a forward direction, anything that interferes with such development causes impaction

ORTHODONTIC THEORY

early loss of primary teeth & mouth breathing may cause malocclusion which further results to impaction

ORTHODONTIC THEORY

dense bone decreases the movement of the teeth in a forward direction → which leads to impaction

PHYLOGENIC THEORY

states that a change in nutritional habits of our civilization have resulted in decrease in size of the maxilla & mandible leaving insufficient space for third molars to erupt in some people

PHYLOGENIC THEORY

• present use of soft & refined food does not require a too much masticatory effort to chew the food, consequently it does not provide sufficient stimulus necessary for jaw growth resulting in evolutionary reduction in size of the human mandible & maxilla making it unable to accommodate the full set of teeth

PHYLOGENIC THEORY

• views third molars as vestigial organs without current purpose or function and that nature tries to eliminate the disused organ by causing the slow regression or atrophy of the organ

MENDELIAN THEORY

• states inheritance traits or heredity as the common etiologic factor

MENDELIAN THEORY

• transmission of small jaws from one parent and large teeth from the other parent would likely result in impaction

PATHOLOGICAL THEORY

chronic infections affecting an individual may bring the condensation of osseous tissue which further prevents the growth & development of the jaws

ENDOCRINAL THEORY

• increase or decrease in growth hormone secretion may affect the size of the jaws

BASIC PRINCIPLES OF IMPACTION

1. Any region of the dental follicle proper has the potential for initiating or regulating bone resorption & bone formation, or not influencing bone activity where ectopic eruption is due to the aberrant activity of the dental follicle.

2. Movement of teeth during eruption consists of preparing a path through the bone or soft tissues & moving them along its path.

3. Formation of the eruption pathway is the rate-limiting step revealed by the rapid catch-up eruption of temporary unerupted teeth.

INCIDENCE / FREQUENCY OF IMPACTION

1. mandibular third molars

2. maxillary third molars

3. maxillary canines

4. mandibular premolars

5. maxillary premolars

6. mandibular canines

7. maxillary central incisors

8. maxillary lateral incisors

ETIOLOGY / CAUSES OF IMPACTION

• SYSTEMIC CAUSES

• LOCAL CAUSES

SYSTEMIC CAUSES

1. Prenatal causes

2. Postnatal causes

3. Endocrine disorders

4. Hereditary-linked disorders

5. Rare conditions

PRENATAL CAUSES

• hereditary factors & miscegenation (cohabitation of 2 people from different racial groups)

POSTNATAL CAUSES

• conditions that may interfere with the development of a child

POSTNATAL CAUSES

• examples: tuberculosis, anemia, rickets, malnutrition, congenital syphilis, etc.

ENDOCRINE DISORDERS

• lack of osteoclastic activity does not provide resorption of the bone overlying the developing tooth

ENDOCRINE DISORDERS

Examples: hypothyroidism, hypopituitarism, achondroplasia, etc.

HEREDITARY-LINKED DISORDERS

There is failure of the overlying bone to resorb & the development of an eruption pathway is absent

HEREDITARY-LINKED DISORDERS

Examples: Down syndrome, gorlin syndrome, hurler syndrome, gardner’s syndrome, cleft palate, osteopetrosis, etc.

RARE CONDITIONS

• dental manifestations would result in severe crowding & rotation of teeth, displacement of teeth, and the delayed development & eruption of teeth

RARE CONDITIONS

• examples: cleidocranial dysostosis or dysplasia, amelogenesis imperfecta, oxycephaly, progeria, etc.

LOCAL CAUSES

1. Inadequate space in dental arch

2. Presence of supernumerary teeth (i.e., hyperdontia)

3. Inclination & rotation of teeth

4. Obstruction of tooth eruption

5. Long continued chronic inflammation

6. Irregularity in the position & pressure of an adjacent tooth

7. Over-retained primary teeth

8. Premature loss of primary teeth

9. Ankylosis of a primary or secondary tooth

10. Dilacerations of roots

11. Ectopic (displaced) position of a tooth bud

12. Non-absorbing alveolar bone (i.e., dense bone)

13. Inflammatory changes in the bone

14. Acquired diseases

15. Associated soft tissue or bony lesions (i.e., fibrosis)

16. Individual parafunctional habits that may include the mouth breathing, tongue thrusting, or thumb sucking

Inadequate space in the dental arch

• manifests as malocclusion, crowding of teeth, or micrognathia (small jaw size)

Presence of supernumerary teeth (i.e., hyperdontia)

• obstructs the pathway for the eruption of other teeth resulting in their impaction

• In many instances, a supernumerary tooth itself may remain impacted due to lack of space for eruption

Inclination & rotation of teeth

• failure of the tooth to be in an upright position from a mesial, distal, lingual, buccal / labial inclination

• Rotation results in the eruption of a tooth at a different angulation in the jaw

*TOOTH INCLINATION

• is the deviation of a tooth from its vertical plane

*TOOTH ROTATION

Is the displacement of a tooth from its longitudinal axis

Obstruction of tooth eruption

• may be due to a malposed tooth (abnormally positioned tooth), high density of the overlying & surrounding bone, or the presence of cysts or tumors that may be odontogenic or non-odontogenic in origin

Long continued chronic inflammation

• results to an increase in the density of the overlying mucous membrane

Irregularity in the position & pressure of an adjacent tooth

• undue amount of pressure may affect the normal direction of tooth eruption

Over-retained primary teeth

An abnormally retained primary tooth may resist the eruption of its secondary counterpart which would lead to an impacted secondary tooth

premature loss of primary teeth

• early exfoliation of a primary tooth causes the partial closure of the space (intended for the secondary tooth) in the alveolar ridge

Ankylosis of a primary or secondary tooth

• results in the impaction of the involved tooth which may include the adjacent teeth in cases when the ankylosis occurs along the eruption pathway

Dilacerations of roots

• abnormal path of tooth eruption due to traumatic forces during the eruption phase

Ectopic (displaced) position of a tooth bud

• displacement of a tooth bud would act as a barrier for other erupting teeth

Non-absorbing alveolar bone (i.e., dense bone)

• results in either a significant delay in eruption or an impaction of the tooth itself

Inflammatory changes in the bone

• due to exanthematous diseases (exhibits skin eruptions and/or rashes) during childhood such as measles, chicken pox, pertussis, mumps, scarlet fever, rubella, etc.

Acquired diseases

• necrosis occurs due to the presence of an infection or an abscess

Associated soft tissue or bony lesions (i.e., fibrosis)

• presence of lesions acts as an obstruction to the normal eruption of a tooth

Individual parafunctional habits that may include the mouth breathing, tongue thrusting, or thumb sucking

• mechanical pressure & force hinders the normal direction of tooth eruption

INDICATIONS FOR REMOVAL OF IMPACTED TEETH

1. Tooth in the line of a fracture or prevention of jaw fracture

2. Tooth in the line of fire (radiation)

3. Prevention of dental caries and unrestorable caries

4. Prevention of an overt infection

5. Prevention of root resorption

6. Facilitation for implant placement

7. Facilitation of orthodontic treatment

8. Facilitation of orthognathic surgery

9. Prevention of periodontal disease

10. Management of preprosthetic concerns

11. Prevention of odontogenic cysts or tumors

12. Management of an abscess, cyst, or tumor of odontogenic origin

13. Obstruction of the normal eruption of a permanent tooth

14. Prevention of pathologic fractures

15. Prevention of pain of unexplained origin

16. Prophylactic removal

TOOTH IN THE LINE OF FRACTURE OR PREVENTION OF JAW FRACTURE

• presence of a tooth in a fracture line increases the risk of infection in some cases, especially when the tooth has been displaced or has been rendered non-vital

TOOTH IN THE LINE OF FRACTURE OR PREVENTION OF JAW FRACTURE

• extraction may be considered in cases of fracture of the mandible in the third molar region (where the tooth is frequently moved before the fracture is reduced & fixation is applied)

TOOTH IN THE LINE OF FRACTURE OR PREVENTION OF JAW FRACTURE

• impacted third molar/s in the mandible occupies space that is often filled with bone → which then weakens the mandible → and renders the jaw susceptible to fracture/s at the site of the impacted tooth

TOOTH IN THE LINE OF FIRE (radiation)

patients receiving radiation therapy should consider extraction for the teeth that will be along the beam of radiation therapy

PREVENTION OF DENTAL CARIES AND UNRESTORABLE CARIES

• predominantly seen in the distal surface of a second molar adjacent to an impacted third molar

• removal must be considered when there is caries formation in the impacted tooth & the tooth is unlikely to be properly restored, or when there is caries formation in the adjacent second molar which cannot be adequately treated without removal of the third molar

PREVENTION OF AN OVERT INFECTION

• this indication will generally exclude transient or self-limiting inflammation that may be associated with the normal eruption of any tooth

PREVENTION OF AN OVERT INFECTION

• removal of any symptomatic impacted tooth should be considered, especially where there have been ≥ 1 episode/s of infection such as pericoronitis (which develops in 75 - 80% of patients with an impacted third molar), cellulitis, abscess formation, or untreatable pulpal / periapical pathology

PREVENTION OF AN OVERT INFECTION

• when a tooth is partially impacted with a large amount of soft tissue over the axial & occlusal surfaces: patient/s frequently have ≥ 1 episode/s of pericoronitis

*PERICORONITIS

inflammation of the gingival tissue surrounding a crown of a partially erupted tooth that is caused by normal oral flora, compromised host defenses, minor trauma from an opposing tooth, or entrapment of food under the operculum or pericoronal flap

*CELLULITIS

erythematous, hot, swollen skin with irregular & distinct margins which fade into the surrounding skin that affect the deep dermis & subcutaneous tissues

PREVENTION OF ROOT RESORPTION

an impacted tooth can occasionally cause sufficient pressure on the root of an adjacent tooth resulting in root resorption

FACILITATION FOR IMPLANT PLACEMENT

when an implant is planned near the position of an impacted tooth: removal is warranted to eliminate the risk of interference with the implantation procedure

FACILITATION OF ORTHODONTIC TREATMENT

if patients require the retraction of the 1st & 2nd molars by orthodontic techniques: presence of an impacted third molar may interfere with this treatment

FACILITATION OF ORTHOGNATHIC SURGERY

in cases when a sagittal split osteotomy is planned: removal of the third molar decreases the risk of surgical complications with regard to that osteotomy