Ectopic Eruption of First Permanent Molars

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Transcript Ectopic Eruption of First Permanent Molars

Anomalies in the Development
of the Dentition
Natal and Neonatal Teeth
Definitions and Prevalence
• Natal Teeth: Teeth that are erupted at birth.
• Teeth Neonatal: Teeth that erupt during the
period of early infancy shortly after birth;
typically characterized as within 30 days.
• Natal/Neonatal Teeth occur in approximately 1
in 3,000 births.
• Typically they are mandibular incisors.
• In 90% of the cases they are prematurely
erupted primary teeth, not supernumeraries.
• Due to the overwhelming prevalence of the teeth being
prematurely erupted teeth, they should be preserved.
• If it can be determined (by radiograph) that they are
supernumerary, then should be extracted. Supernumerary natal
and neonatal ‘teeth’ appear to be calcific nodules that do not
have the morphological appearance of a primary tooth.
• Typically are somewhat mobile due to immature root formation.
• Physicians and nurses will frequently ask that they be extracted
due to concern about become dislodged with swallowing or
aspiration. Also concern regarding interfering with nursing.
• Unless it is determined that the natal/neo-natal teeth are
supernumerary, pressure to extract should be resisted, as the
teeth are more resistant to dislodging than thought. Teeth are
typically not an impediment to nursing as mothers’ nurse their
infants for a considerable period subsequent to the eruption of
all of the incisor teeth.
Eruption Hematoma
• Eruption hematoma’s are
sometimes referred to as
an “eruption cyst.”
• Essentially a dilatation of
the normal follicular space
around the crown of the
erupting tooth caused by
the accumulation of tissue
fluid or blood.
• Most commonly occur with
eruption of primary teeth,
although also noted with
eruption of first
permanent molars.
• No therapy is required.
Cysts Inclusions of the Newborn
• Inclusion cysts of the newborn infant are of two
• Bohn’s nodules are smooth whitish cysts of 1-3 mm
in size filled with keratin. They are found on the
buccal and lingual of the dental ridges and are the
result of cystic degeneration of epithelial rests of
the dental lamina. They are benign and usually
disappear within the first three months of life.
• Epstein’s pearls are small cystic vesicles of 1-3 mm
in size seen in the medial palatal raphe of newborn
infants—they are commonly present. They are
caused by the entrapment of epithelium during the
development of the palate. They resolve
spontaneously and do not require treatment.
Bohn’s Nodules
Epstein Pearls
Fusion and Gemination
(“Double Teeth”)
• Fusion is defined as a the conjoining of two
teeth. When the teeth are counted and
the anomalous tooth is counted as one, a
tooth is missing.
• Gemination is defined as ‘two teeth’
developing from one tooth bud, and when
the teeth are counted the individual is not
missing a tooth.
• Counting the teeth is critical to
determining whether the anomalous tooth
is fused or geminated.
Fusion of Primary Teeth
Prevalence of fusion is estimated to be between 0.5% and 2.5% in the
primary dentitions. It is seen much less frequently in the permanent
dentition .
Geminated and fused primary teeth are essentially phenomenon
related to primary anterior teeth.
Generally no treatment is required, though decay may occur if a
crevice exists in the “double tooth.” Additionally, if the root is
involved, thus larger than normal, and is delaying the eruption of the
succedaneous tooth, the primary tooth may have to be extracted.
Anomalies exist in permanent incisors approximately 50% of the time
when there are anomalies of the primary incisors. (Gellin)
Ectopic Eruption of
First Permanent Molars
Definition and Significance
• A condition in which the permanent first
molar assumes a path of eruption that
intercepts the distal root of the second
primary molar causing its resorption with
the potential to cause premature of the
second primary molar.
• Problematic that in doing so there is a loss
of arch circumference ultimately
compromising the eruption of the second
Characteristics and Prevalence
• Ectopic eruption of the first permanent
molar occurs in 2-4% of the population.
• Most common in the maxillary; relatively
infrequent in the mandibular arch.
• Associated with inadequate arch
circumference—typically the lower incisors
will be “crowded.”
• Self-correction occurs in approximately
66% of the cases.
• Generally requires appliance intervention if
not self-corrected by age 7.
Ectopic Eruption
Halterman Appliance Correction
Halterman Appliance
• Primary molar band is fitted on second primary molar.
• If a primary molar band is not maintained in the office, the
occlusal surface can be cut out of a stainless steel crown
that fits the tooth and used as alternative.
• A compound impression with the band in place is then sent
to a laboratory such as “Space Maintainers Laboratory
(information for submission on the internet) with
instructions to fabricate a Halterman Appliance.
• On return an orthodontic button is attaced to the occlusal
of the partially erupted first permanent molar through acid
etching and adhesion with a resin; the Halterman appliance
is cemented to the second primary molar; and a orthodontic
elastic chain is stretched over the button engaging the loop
in the Halterman Appliance.
• Child should be seen in one week with elastic changed, and
every 2-3 weeks until correction has occurred; varying from
4-12 weeks,
Subsequent to Correction
While the pulp typically is involved, rarely does
pulpal necrosis occur and the second primary
molar remains in place until eruption of the
second premolar.
If Not Corrected, Arch
Circumference Lost with Molar
Shifting Forward
If Not Treated and Arch
Circumference is Lost, Head
Gear Necessary to Regain Lost
NO Space Maintainer
• Do not place a space maintainer after
the first permanent molar has already
migrated forward and space has been
• Space maintainers are only to be used
for maintaining adequate space.
• Once space is lost a space regainer is
Infra-occlusion of Primary
Posterior Teeth
(Submersion, Ankylosis)
An aberration in the eruption of
teeth in which the continuity of the
periodontal ligament becomes
compromised during bone remodeling
during growth of the alveolus, with
fusion of the cementum and bone at
one or more locations/teeth do not
move with the continuing vertical
growth of the alveolar arch.
Results in the tooth being in infraocclusion or “submerged” relative to
the occlusal plane.
Prevalence 3-4%, with mandibular
first primary molar most commonly
ankylosd, and typically between 7-11
years of age.
Infra-occlusion of Primary
Posterior Teeth
(Submersion, Ankylosis)
• When ankylosis is minor or
questionable, can be diagnosed
by a dull sound on percussion of
the tooth.
• One study found that only 3-4%
of ankylosed primary molars did
not exfoliate normally and
required extraction.
• However, due to adjacent
posterior tooth tipping into the
space, a full arch space
maintainer (lingual arch or
Nance arch) must be placed to
preserve arch circumference.
Do not permit the infraocclusion to go past the point of
proximal contact.
• Most common
supernumerary tooth;
defined as
existing in the
maxillary midline.
• Prevalence is up to 2%
of population.
• Can interfere with
eruption of permanent
central incisor(s).
• Only approximately 25%
of mesiodens erupt.
• Majority are conical in
shape, vertically aligned
and positioned to the
• Timing of surgical
removal is critical with
tension between not
adversely affecting
permanent incisor tooth
bud, and not interfering
with the normal
eruption of the incisor.
Congenital Agenesis of Teeth
• Hypodontia refers to the congenital absence
of one to five teeth excluding the third molars.
• Oligodontia refers to the congenital absence of
six or more teeth excluding third molars.
• Anodontia refers to the complete absence of
permanent teeth.
• Meta-analysis of the research literature
indicates that mandibular second premolars are
most commonly missing tooth (±3.0%), followed
by the maxillary lateral incisor (1.0-2.0%). and
the maxillary second premolar (1-1.5%).
Agenesis of Second Premolar
Second Primary Molar can
frequently be maintained for an
indefinite period of time.
Management must be based on
overall assessment of occlusal
One study found that only 7 of 59
retained primary molars were lost
between 12 and 20 years of age, and
none after age 20 during the
observation period.
Sound prevention practices critical
to preservation of the tooth.
Frequently, the primary molar
becomes ankylosed creating the
potential for loss of arch
circumference, and must be
If orthodontics is required the
teeth may be sacrificed.
If lost later in life, an implant may
be employed to replace the missing
Agenesis of Maxillary Lateral Incisor
Management can be complex.
Options include:
– Substituting the canine for
the lateral with reconturing
of the canine. Orthodontic
movement may be required
achieve the most favorable
esthetic result.
– Orthodontic movement to
permit prosthetic
replacement initially with
resin-retained prosthesis
(Maryland Bridge) ;
ultimately replacement with
an implant and crown.
Anomalies of
Peg Shaped Teeth
Hutchinson’s Incisors
of Congenital Syphilis
(Morphodifferentiation and Apposition)
Mulberry Molars
of Congenital Syphilis
(Morphodifferentiation and Apposition)
Dens in Dente
Dens in Dente or dens invaginatus is a malformation of teeth most likely
resulting from an infolding of the dental papilla during tooth
development or invagination of all layer of the enamel organ in the dental
papillae. Teeth most affected are maxillary lateral incisors and bilateral
occurrence is not uncommon. The malformation shows a broad spectrum
of morphologic variations and frequently results in early pulpal
necrosis. Root canal therapy may present severe problems because of the
complex anatomy of the teeth.
Taurodontism is a condition found in the molar teeth
of humans whereby the body of the tooth and pulp chamber is enlarged
vertically at the expense of the roots. As a result, the floor of the pulp
and the furcation of the tooth is moved apically down the root.
The underlying mechanism of taurodontism is the failure or late invagination
of Hertig’s epithelial root sheath, which is responsible for root formation
and shaping causing an apical shift of the root furcation.
Anomalies of Apposition
Fluorosis (Mottled Enamel)
Mild Fluorosis:
Found in ± 6% of children
Moderate Fluorosis:
Found in ± 1-2% of children
Severe Fluorosis
Found in ± 1% of children
Amelogenesis Imperfecta
Amelogensis Imperfecta
• Literally, imperfect enamel formation. A defect of
• Prevalence 1 in 700 to 1 in 15,000.
• Four types: Hypoplasitic--a defect in the amount of
enamel; Hypomaturation-- defect in maturation of enamel;
Hypocalcified—defect in initial crystal formation;
• Various types present various clinical appearances.
• Transmitted as Autosomal Dominant (50% of offspring
affected); Autosomal Recessive (25% of offspring
affected ); and X-linked recessive (no male to male
transmission; all daughters carriers—with 50% of their
offspring affected).
• Fourteen different mutations of gene.
Dentinogenesis Imperfecta
(Hereditary Opalescent Dentin)
Dentinogenesis Imperfecta
(Hereditary Opalescent Dentin)
• Inherited in an autosomal dominant pattern.
• A defect in dentinogensis.
• Prevalence estimated at 1 in 6,000 to 8,000
• Type I can occur as a recessive trait with
osteogenesis impefecta. Teeth most severely
affected are primary teeth versus permanent.
• Type II occurs without other inherited
disorders; both dentitions equally affected.
• Pulp chambers become obliterated.
• Molar-incisor hypomineralization
describes the clinical picture of
hypomineralization of systemic
origin affecting one or more first
permanent molars that are
associated frequently with
affected incisors.
• Etiological associations with
systemic conditions or
environmental insults during the
child's first 3 years have been
• Prevalence studies highly variable
from 6% to 25%
• Management: Early diagnosis,
sealants, stainless steel crowns,
bleaching, composites.