1. Mohammed Almuzian, University of Glasgow, 2014 Page 1
Prolonged retention, Ankylosis and infraocclusion of
deciduous teeth
Ankylosis and infraocclusion
 A tooth becomes ankylosed when the periodontal ligament is lost and direct
fusion occurs between root cementum and the surrounding alveolar bone.
 Prolong retention of primary teeth; most commonly affect the Ds or Es.
Prevalence
 Ankylosis most commonly affects lower deciduous molars.
 14% of children at age 8-9 and 2% above 12 years) (Kurol, 1981).
 More common among relatives
Aetiology
1. Syndromic
2. Non-Syndromic
 Genetic
 Trauma
 Infection
 Radiation and chemicals
 Congenital absenceof the second premolar.
 Idiopathic
 Iatrogenic
Managementis dictated principally by
1. The presence or absence of the unerupted permanent tooth
2. The position of the unerupted permanent tooth

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3. The long-term prognosis of the deciduous
4. Inter and intra-maxillary relationship
Classification
1. Mild: The entire occlusal surface is located at least 1 mm below the occlusal
plane and above the contact point of the adjacent non-ankylosed teeth.
2. Moderate: The entire occlusal surface is located below the contact point level
but above the CEJ of adjacent tooth.
3. Severe: The entire occlusalsurface is level with or below the CEJ of the
adjacent tooth.
Management
1. In the presence ofa permanent successorand minimal infraocclusion, the
ankylosed tooth can usually be left under observation to exfoliate naturally. If
the infraocclusion becomes greater this can lead to displacement, tipping and
overeruption of adjacent teeth. In these circumstances, consideration should be
given to either restoring the vertical dimension or extracting the affected tooth
with lingual or palatal arch to maintain the space.
2. In the absence ofa permanent successor orif the permenant tooth is
severelydisplaced, the Treatment options
A. Retention of the second deciduous molar.
B. Early Extraction to facilitate spontaneous spaceclosure. It is better to allow
permanent teeth to drift into the edentulous spaceand bring bone with them, and
then reposition the teeth prior to implant or prosthetic replacement, so that large
periodontal defects do not develop.
C. Premolaizing the E
D. Slicing and spaceclosure
E. Extraction and prosthetic replacement;

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However, any of the following features, either alone or in combination, will
demonstrate a potentially poorprognosis:
 Caries
 Rootresorption
 Bone resorption
 Periapical or inter-radicular pathology
 Ankylosis
 Infraocclusion
 Gingival recession
If they survive to twenty years of age, continued long-term function can be
anticipated (Bjerklin & Bennett, 2000)
Consequencesof infra-occluded deciduous teeth
1. Delayed exfoliation
2. Delayed eruption of successor
3. Tipping of the adjacent teeth due to stretching of the transeptal fibers.
4. Overeruption
5. Resorption of proximal root surface
6. Damage to adjacent teeth
7. Progression of submergence
8. Ankylosis with subsequent increased difficulty of extraction
9. Tongue habits and open bite
Recommendedapproaches forthe managementof impacted and ankylosed
anterior maxillary teeth include: (Urebi 2013)
 Extraction of the ankylosed tooth followed by prosthetic replacement.
 Surgical luxation of the tooth followed by orthodontic traction.
 Surgical luxation followed by periodontal ligament distraction.

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 Osteotomy of the dentoalveolar segment with immediate repositioning of the
dentoalveolar structures.
 Osteotomy followed by intraoral distraction.
 Osteotomy followed by heavy orthodontic forces.
 Osteotomy followed by a combination of dentoalveolar distraction and light
orthodontic forces.
 Osteotomy followed by conventional orthodontic forces.
 Osteotomy with partial repositioning followed by heavy orthodontic forces.
 Lingual corticotomy of the dentoalveolar segment, followed by a labial
corticotomy three weeks later and a conventional orthodontic force.
Asymmetric Dental Development
 Asymmetric eruption (one side ahead of the other by 6 months or more) is
significant. It requires careful monitoring of the situation, and in the absence of
outright pathology, often requires early treatment such as selective extraction of
primary or permanent teeth.
 Aetiology: genetic, syndromic, systemic (like hormonal, nutritional,
chemotherapy) or localized like trauma, infection or radiation.
 A few patients with asymmetric dental development have a history of childhood
radiation therapy to the head and neck or traumatic injury.
 Surgical and orthodontic treatment for these patients must be planned and timed
carefully and may require tooth removal or tooth reorientation.
 Some of these teeth have severely dilacerated roots and will not be candidates
for orthodontics these situations definitely fall into the complex category and
usually require early intervention.

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OverretainedPrimary Teeth
 Definition: A difference of more than six months between the shedding of
contralateral teeth should be regarded with suspicion. Provided that the
permanent successoris present
 Aetiology: genetic, syndromic, systemic (like hormonal, nutritional,
chemotherapy) or localized like trauma, infection or radiation.
 A permanent tooth should replace its primary predecessorwhen approximately
three-fourths of the root of the permanent tooth has formed, but a primary tooth
that is retained beyond this point should be removed because it often leads to
gingival inflammation and hyperplasia that cause pain and bleeding and sets the
stage for deflected eruption paths of the permanent teeth that can result in
irregularity, crowding, and crossbite.
 If a portion of the permanent tooth crown is visible and the primary tooth is
mobile to the extent that the crown will move 1 mm in the facial and lingual
direction, it is probably advisable to encourage the child to “wiggle” the tooth
out. If that cannot be accomplished in a few days, extraction is indicated. Most
overretained primary maxillary molars have either the buccal roots or the large
lingual rootintact; most overretained primary mandibular molars have either the
mesial or distal root still intact and hindering exfoliation
 Once the primary tooth is out, if spaceis adequate, moderately abnormal facial
or lingual positioning will usually be corrected by the equilibrium forces of the
lip, cheeks, and tongue.