Article Title: Decoronation for the management of an ankylosed young permanent tooth
Author(s): Sapir S, Shapira J
Journal: Dental Traumatology
Date: 2008; 24(1); 131-5
Major Topic: Decoronation
Type of Article: Case report
Main Purpose: This article aimed to review the considerations involved in the decoronation procedure and review a case of an ankylosed permanent incisor.
Key Points: Decoronation should be a consideration in managing cases of ankylosed permanent incisors.
· Replacement resoprtion (AKA ankylosis) may be reversible, but if extensive, progresses until the root substance is totally remodeled to bone
· Rate of replacement resorption depends on:
a. Tooth lost within 3-7 years if 7-16 years old. Tooth may survive ≥20 years in adults
2. Basal metabolic rate
3. Extra-avelolar time
4. Treatment of root surface prior to replantation
5. Amount of root dentin at time of trauma
6. Severity of trauma
7. Extent of periodontal ligament necrosis
· Complications of ankylosed permanent incisors:
1. Inflammatory root resorption
2. Esthetic compromise due to disharmony of smile from change in arch position
3. Orthodontic complications due to arch irregularity
4. Lack of mesial drift
5. Tilting of adjacent teeth
6. Arch length loss
7. Future prosthetic complications due to loss of alveolar bone
· Considerations for removal of ankylosed tooth:
o Loss of function
o Future rehabilitation considerations – bone level
· Treatment of avulsed root with doxycycline and Emdogain (enamel matrix derivative) may enhance periodontal cell recovery
· Treatment options for an ankylosed:
o Early extraction and esthetic solution until more conclusive treatment is provided in future
§ Not recommeneded because extraction may damage alveolar bone and the tooth may be retained satisfactorily for a few years before functional and esthetic complications arise
o Orthodontic space closure
§ Limited by orthodontic diagnosis and tooth – skeletal age and growth, malocclusion, dental age
§ Lateral incisors are easier to replace than centrals
o Intentional replantation: extraction of ankylosed tooth as soon as ankylosis is diagnosed and then replanting it
§ Discouraging long-term results
§ Guarantees ankylosis
o Extraction of ankylotic tooth followed with immediate ridge augmentation/preservation
§ Consider when tooth is lost spontaneously or when the ankylosed tooth must be extracted early due to orthodontic or prosthetic requirements
§ May be preferred over decoronation when orthodontic space closure is attempted or implant solution is planned earlier than the ankylotic root is expected to remodel
§ Lower 1st premolar <75% developed
§ Depends on orthodontic diagnosis
§ Risk of damage to alveolar bone site
§ Not recommended in adolescents over 12-14 years old
o Single tooth dento-osseous osteotomy: transposition of ankylotic tooth with bone to a more coronal position
§ Reserved for adult patients because it does not resolve replacement resorption process, which is accelerated in adolescents
o Decoronation and esthetic space maintenance until more definitive treatment is provided
o Remove crown beneath CEJ 1mm under crestal bone margins. Remove all root canal fillings/medicaments. Initiate bleeding from coronal and apical sides to encourage blood coagulum formation inside the canal. Primary closure of flap to encourage soft tissue healing and vertical bone apposition.
o Indications for decoronation
§ Child/adolescent with ankylosed permanent incisor with future rehabilitation plan of an implant or bridge without medical, surgical, or orthodontic contraindications
§ Root is not expected to resorb within a year
§ Preservation of alveolar process width and height
§ Simpler and more economical than ridge augmentation
§ Vertical bone apposition is possible
o Disadvantages: surgical nature and need for long-term esthetic space maintainer
o Ideally performed 2 years before implant placement to allow root to be full remodeled
o Recommended when crown is 1/8 to ¼ infraoccluded compared to homologous tooth in a growing child
o Must follow children more closely who are close to growth spurt about every 3 monthts. May follow patients about once a year who are past their peak growth.
o 12 year old boy who had avulsed #8 2 years ago and had RCT performed on it. Avulsed tooth had 2 hours of extra-oral dry time before being re-implanted.
o Decoronation was performed and a pedi-partial space maintainer was placed to replace #8.
o Orthodontics was performed 3 years later.
o 4 years after decoronation, the decoronated root showed further replacement resorption and 1mm of bone coronal to decoronation level.
o Implant is planned for 2 years later.
Assessment of Article: Level of Evidence/Comments: III