Delayed tooth eruption (DTE) is defined as the emergence of a tooth significantly later than the norm due to various factors such as physical obstructions, systemic conditions, and genetic disorders. The document outlines the etiology, clinical implications, pathogenesis, and treatment options for DTE, emphasizing the importance of thorough evaluation and diagnosis by dental professionals. It also highlights the controversies in terminology surrounding DTE and the need for tailored therapeutic considerations based on individual cases.

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Delayed tooth eruption Dr. Mohammed Alruby
Delayed
Tooth
Eruption
Prepared by:
Dr. Mohammed Alruby

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Delayed tooth eruption Dr. Mohammed Alruby
Delayed tooth eruption
Definition DTE:
It is the emergence of a tooth into the oral cavity at a time that deviates significantly from norms
established for different races, ethnicities, and sexes
Eruption:
The developmental process responsible for moving a tooth from its crypt position through the
alveolar process into the oral cavity to its final position of occlusion with its antagonists.
Physiologic process that strongly influences the normal development of the craniofacial
complex.
Its dynamic process that encompasses:
1- Completion of root development.
2- Establishment of the periodontium.
3- Maintenance of the functional occlusion.
Factors influencing tooth eruption:
- Broad chronologic age range.
- Race
- Sex
- Ethnic
- Individual variation
Emergence (Moment of eruption):
The moment of appearance of any part of the cusp or crown
through the gingiva.
Impacted teeth:
Teeth prevented from erupting by some physical barrier path.
Etiology:
1- Lack of space Due to crowding of the dental arches or premature loss of deciduous
teeth
2- Rotation or other positional deviation of the tooth buds.

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Delayed tooth eruption Dr. Mohammed Alruby
Results in teeth that are “aimed” in the wrong direction, leading to impaction.
Primary retention:
- Cessation of eruption of a normally placed and developed tooth germ before emergence.
- No physical barrier.
Pseudo-anodontia
Clinical but not radiographic absence of teeth that should normally be present in the patient’s
dental and chronologic age.
the deciduous teeth have been shed, but the permanent ones failed to erupt.
Primary or idiopathic failure of eruption :(Proffit and Vig):
Non-ankylosed teeth fail to erupt fully or partially
- Because of malfunction of eruption mechanism.
- No barrier to eruption.
- Primary defect in in the eruptive process.
Arrested eruption or non-eruption:
- Ankylosis
- Impaction
- Idiopathic failure of eruption
Embedded teeth:
Unerupted due to lack of eruptive force.
No obvious physical obstruction.
Submerged teeth and inclusion/re-inclusion of teeth:
- After eruption, teeth become ankylosed.
- Lose their ability to maintain the continuous eruptive potential as the jaws grow.
- Lose contact with their antagonists.
- Might re-include in the oral tissue.
Eruption is normal according to chronologic and biologic parameters (root formation),
BUT the process was haltered.

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Delayed tooth eruption Dr. Mohammed Alruby
Controversy between the terms:
“delayed”, “late”, “retarded”, “depressed” and “impaired”
a- Root development as a basis for distinguishing some of these terms (Gron,1962):
Under normal circumstances, tooth eruption begins when ¾ of its final root length is
established.
- Mandibular canines and second molars root development > ¾of final root length.
- Mandibular central incisors and first molars root development < ¾ final root length.
b- Root Development alone should be the basis for defining the expected time of eruption
for different teeth (Becker).
Root development < ¾ root length = premature eruption.
Root development > ¾ root length = delayed eruption
c- Norms for mean eruption ages calculated from population studies (Rasmussen and Kotsaki)
When the emergence of a tooth > 2 standard deviations (SDs) from the mean of established
norms of eruption
= Delayed eruption: Used in the basis of root development:
= “Late” and “Retarded” eruption
Parameters that influence DTE:
1- Chronologic age – Expected tooth eruption time.
- Ease of use.
- Helps forming a baseline for further clinical evaluation of a patient.
2- Biologic eruption – Progression of root development.

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Delayed tooth eruption Dr. Mohammed Alruby

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Delayed tooth eruption Dr. Mohammed Alruby
Pathogenesis and differential diagnosis:
Local condition:
1- Physical Obstruction:
a- Supernumerary teeth
Crowding
Displacement
Rotation
Delayed eruption:
- Most common type: Mesiodens followed by 4th molar.
- Tuberculate type = DTE. Conical form= Displacement.
b- Mucosal barrier
History of trauma or surgery.
Gingival Hyperplasia (Hormonal, hereditary, Vit D deficiency, drugs such as Phenytoin.)
c- Scar tissue
d- Tumors
e- Odontomas
DTE is the altering sign for diagnosing the condition.
2- Regional Odontoplasia: (Ghost teeth):
Dental anomaly result from a somatic mutation or latent virus in the odontogenic
epithelium.
Causes delay or total failure of eruption.
Irregular shape with defective mineralization.
Central incisors, lateral incisors and canines are most frequently affected.
3- Injuries to deciduous teeth
Ectopic eruption
Dilaceration
Physical displacement of the permanent tooth germ.
Ankylosis or delayed root resorption.
4- Cystic Transformation of a non-vital deciduous incisor.
5- Premature loss of deciduous teeth before the beginning of their root resorption.
Abnormal changes in the connective tissue overlying the permanent tooth
= Thick fibrous gingiva.

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Delayed tooth eruption Dr. Mohammed Alruby
6- Ankylosis of the deciduous dentition: Fusion of cementum or dentin with the alveolar
bone. Ankylosed teeth will remain stationary, while adjacent teeth continue to
erupt(Infraocclusion).
7- Arch length deficiency: Causes crowding and impaction, DTE, and Ectopic eruption
8- X-radiation
- Ankylosis of bone to tooth
- Root formation impairment
- Periodontal cell damage
- Insufficient mandibular growth
Systemic conditions:
1- Nutrition: Influence on calcification = only in extreme cases
2- Disturbance of the endocrine gland
- Hypothyroidism (Cretinism).
- Hypopituitarism (Pituitary dwarfism).
Smaller dental arch – Malocclusion.
Shorter roots – supporting structure retarded in growth.
- Hypoparathyroidism
- Pseudo-hypoparathyroidism
3- Premature/low birth weight
- DTE of deciduous dentition.
- Catch-up development occurs in later infancy
- Permanent dentition delay = approximately 3 months (birth weight<1500g)
4- Human Immunodeficiency Virus (HIV)
- DTE directly associated with clinical symptoms.
- Associated with the onset of the clinical symptoms.
- Socioeconomic status – poorer nutrition or health.
5- Cerebral Palsy.

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Delayed tooth eruption Dr. Mohammed Alruby
6- Systemic conditions associated with impairment of growth
- Hypoxic hypoxia
- Histo-toxic hypoxia
- Anemic hypoxia
7- Renal failure
Genetic disorder
1- Supernumerary teeth: Apert syndrome, Gardner syndrome, Cleidocranial dysplasia
2- Lack of cellular cementum: Cleidocranial dysplasia
3- Cementum-like proliferations + obliteration of PDL = Ankylosis (Gardner Syndrome)
4- Lack of appropriate inflammatory response, an inadequate expression of some
cytokines, and increased bone density== impedes resorption causing DTE.
Osteopetrosis, Sclerostenosis, Carpenter syndrome, Apert syndrome, Cleidocranial
dysplasia
5- Enhanced bone resorption
Hyper-immunoglobulin E syndrome.
6- Tumors and Cysts: Gorlin syndrome, Cherubism, Gardner syndrome
7- Delayed development of isolated teeth = premolar region.
Clinical implications:
1- Medical history
2- Clinical examination
a- Overall physical evaluation
b- Right-left variations in eruption timing, Tumors or hemi-facial microsomia or
macrosomia = further investigation
c- intraoral examination
- Inspection, pathology, scars, swellings, fibrous or dense frenal attachment.
- Palpation, Bulge of tooth in process of eruption. Pathology: pain, crackling.
- Percussion
- Radiograph examination.

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Delayed tooth eruption Dr. Mohammed Alruby
- Over-retained deciduous tooth: examine tooth and supporting structure.
Ankylosed tooth interferes with vertical development of the alveolus.
Might lead to deflection of the succedaneous tooth and damage of adjacent teeth.
- DTE of the maxillary canines:
The maxillary canines develop high in the maxilla, must descend more than its length to
reach its position in the dental arch.
= Etiology of DTE of the Canines is multifactorial:
1- Ectopic development of tooth germ (Genetic)
2- Familial association
3- Abnormal lateral incisor in the same quadrant
4- Developmental anomaly in this part of the maxilla, which contains one of the
embryonic fusion lines (hereditary syndrome)
- Permanent tooth agenesis (excluding 3
rd
molars): 1.6% to 9.6% of the population, most
commonly missing teeth: mandibular second premolars and maxillary lateral incisors
3- Radiographic examination
5- Panoramic radiograph.
6- Parallax method (Image/tube shift method, Clark’s rule, Buccal object rule):
Localization of tumors, supernumerary teeth and displaced teeth.
7- Computed tomography: High cost, High radiation dose
Therapeutic consideration:
The main considerations for teeth affected by DTE:
1- Decision to remove or retain the tooth affected by DTE.
2- The use of surgery to remove obstruction.
3- Surgical exposure of teeth affected by DTE.
4- The application of orthodontic traction.
5- The need for space creation and maintenance.
6- Diagnosis and treatment of systemic disease that causes DTE.
DTE with defective tooth development:
1- Defect localized or generalized.
2- Deciduous tooth defect, space maintained where indicated.
3- Unerupted deciduous teeth with serious defect = extraction
Time of extraction should be defined carefully by considering the development of the
succedaneous teeth and space relationships.
4- Unerupted permanent teeth closely observed until:
the skeletal growth period necessary for appropriate development
preservation of the surrounding alveolar ridge has been attained.
5- If defect is not in the supporting apparatus of the tooth
Exposure of the effected tooth = might bring about the eruption.
6- Defective tooth may serve as an abutment once they have erupted
DTE with no obvious developmental defect in the affected tooth or teeth on the radiograph
Evaluate: Root development, Tooth position, Physical obstruction
1- Absence of ectopic tooth position
No physical obstruction

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Delayed tooth eruption Dr. Mohammed Alruby
Biologic eruption status is within normal limits
Periodic observation
2- Inadequate root formation of succedaneous tooth
= Root development followed up by periodic radiograph examination.
= If tooth lagging in its eruption status
active treatment is recommended >2/3 root developed.
3- Ectopic position of the developing tooth
- Self-correct.
- If significant migration = Extraction.
- If self-correction is not observed over time = Active treatment.
Exposure + orthodontic traction
- If the ectopic teeth deviate > 90° from the normal eruptive path (Auto-transplantation)
4- Obstruction causing DTE:
= Not obvious on radiograph, Soft tissue barrier
Treatment: Uncover – enamel exposure.
= Obvious on radiograph, Supernumerary teeth, tumors, bony sequestration
Treatment: Remove obstruction.
a- Obstruction in deciduous dentition:
Rare
Scar tissue due to trauma = anterior region.
Peri-coronal odontogenic cyst
Neoplasm
Treatment:
- Observation
- Removal of physical obstruction
- Orthodontic traction = rare cases
- extraction of involved tooth.
b- Obstruction in permanent dentition:
Treatment: Removal of the physical obstruction.
Neoplasm = Surgical approach.

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Delayed tooth eruption Dr. Mohammed Alruby
Affected tooth deep in bone = the follicle around it should be left intact.
Surgical approaches for uncovering impacted teeth:
- Gingivectomy
- Apically positioned flap
- Flap/closed eruption
- Pre-orthodontic uncovering technique.
After removing physical barrier, Two options:
a- Exposure of the tooth (McDonald and Avery)
b- Providing sufficient space for the unerupted tooth to erupt spontaneously (Houston and
Tulley) 54%-75% of teeth erupt spontaneously.
If tooth is exposed at the time of surgery, Might or might not be subjected to orthodontic traction.
If Deciduous tooth is a physical barrier, remove deciduous tooth to allow spontaneous eruption.
If Arch deficiency creates a physical obstruction, Expansion of the dental arch
Extraction of affected or adjacent tooth
When several teeth in a quadrant are unerupted, there is a Lack of adequate anchorage and
Osseo-integrated implants are used for anchorage.
DTE associated with Systemic Disorders
1- Generalized DTE
2- Due to Systemic diseases
a- Endocrine disorders
b- Organ failures
c- Metabolic disorders

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Delayed tooth eruption Dr. Mohammed Alruby
d- Drugs
e- Inherited and genetic disorders
Treatment:
- Observation
- Elimination of obstacles to eruption
- Exposure of affected teeth, With or without orthodontic traction.
- Auto-transplantation
- Control of systemic disease
N: B:
= Significant deviations from established norms of eruption should alert the clinician, for
Further investigate patient’s health and development.
= DTE might be:
1- Local
2- Systemic condition
3- Altered physiology of the craniofacial complex.
= Orthodontists perform an early evaluation of craniofacial structures clinically and
radiographically.
Proper evaluation of DTE in orthodontic diagnosis and treatment planning, requires a clear
definition of the term and its significance.
= Diagnostic “tree” = to perform accurate and thorough orthodontic diagnosis of the patient
with DTE.