Modified Orthodontic Bone Stretching for Ankylosed Tooth Repositioning: A Case Report.

Claudio Stacchi1, *
, Luca Barlone1
, Antonio Rapani1
, Federico Berton1
, Luca Contardo1
, Roberto Di Lenarda1

1 Department of Medical, Surgical and Health Sciences, University of Trieste, Trieste, Italy

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© 2020 Stacchi et al.

open-access license: This is an open access article distributed under the terms of the Creative Commons Attribution 4.0 International Public License (CC-BY 4.0), a copy of which is available at: ( This license permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

* Address correspondence to this author at the Department of Medical, Surgical and Health Sciences, University of Trieste, Trieste, Italy; Tel: +0481531229; E-mail:



Different approaches were proposed in the literature for the treatment of malpositioned ankylosed teeth. The present case report describes a modification of Orthodontic Bone Stretching Technique (OBS) for the repositioning of ankylosed teeth, consisting of dentoalveolar segmental osteotomies performed with piezoelectric instruments followed by orthodontic and orthopedic traction.

Case Report:

A 22-year-old female in good general health was referred by her orthodontist due to an infraoccluded and ankylosed maxillary upper left canine. Attempts of conventional and corticotomy-assisted orthodontic alignment of the tooth were previously performed with no success. After elevating a full-thickness flap, three osteotomies were performed by using piezoelectric inserts (Piezotome Cube, Acteon, Merignac, France). Mesial and distal cuts were full-thickness osteotomies, parallel to the long axis of the tooth, through the buccal and palatal cortical plates. The apical osseous incision was a horizontal corticotomy, involving only the buccal plate, and connecting the vertical osteotomies two millimetres over the apex of the tooth. Heavy orthodontic forces were immediately applied by using both dental and skeletal anchorage. The initial movement of the dentoalveolar segment was observed three weeks after surgery and case finishing has been completed in two months. At a one-year follow-up, the repositioned canine showed good periodontal conditions, no discoloration and positive pulp response to the electric test.


Modified OBS technique was effective in repositioning an infraoccluded and ankylosed maxillary canine, providing satisfactory function and esthetics with short treatment time.

Keywords: Ankylosed tooth, Tooth repositioning, Piezosurgery, Surgically assisted orthodontics, Case report, Orthodontic bone stretching technique.