Introduction
Adult orthodontic patients are more common seeking orthodontic treatment these days. According to the American Association of Orthodontists, nearly one – third of all the patients receiving comprehensive orthodontic treatment are those older than 18 years. Management of adult orthodontic patient is different, as they generally require interdisciplinary interaction from the beginning of treatment. Another important aspect is that they demand early completion of Orthodontic treatment. Adult patients generally have missing teeth, especially in the mandibular posterior region. Management of such edentulous spaces is a challenge with limited options like: placement of fixed dental prosthesis or dental implants or orthodontic space closure. Orthodontic space closure demands prolonged treatment time and meticulous planning.
Dentoalveolar distraction osteogenesis for rapid orthodontic tooth movement is an optimistic alternative technique in management of edentulous space (orthodontic space closure) as well as it is a novel procedure that minimize the total orthodontic treatment period by approximately 70 to 80%, with no adverse effects on adjacent structures.1
In present clinical innovation a case of young adult female presented with edentulous space in mandibular right posterior region was successfully managed with dentoalveolar distraction by utilizing a modified dentoalvelar distractor made from mandibular hyrax appliance.
Figure 2
(A) Selection of appropriate mandibular hyrax and stablization, (B) Soldering of mandibular hyrax appliance, (C) Trimmed, finished and polished modified mandibular hyrax appliance.
Figure 3
(A)softl incision and reflection of flap, (B): corticitomy ridge splitting and socket expansion, (C): intermittent bicortical perforations on distal side of mandibular second molar.
Fabrication of the modified dentoalveolar distractor using mandibular hyrax
Edentulous space 10 mm, old extraction at tooth number 46 region, was present in mandibular arch. Band selection was done for tooth number 44,45 and 47 [Figure 1 A,B and C].
Band transfer was done and dental cast was made with type 2 dental stone [Figure 2 A]
Mandibular hyrax (11mm) fully opened, was adapted along the buccal surface in the mandibular posterior region right side. The assembly was stabilized with dental plaster and mandibular hyrax was soldered to molar and premolar bands. [Figure 2 A and B]
The new dentoalveolar distractor was appropriately trimmed, finished and polished [Figure 2 C].
The finished and polished distracter was checked for its adaptation in the patient’s mouth and was kept ready for cementation after the surgical procedure.
Surgical Prcedure
To facilitate rapid tooth movement i.e., accelerated molar mesialisation, corticotomy procedure was performed:
An alveolar crestal incision was given on the edentulous ridge and full thickness flap was raised. [Figure 3 A]
Ridge splitting and socket expansion was done to create space for molar mesialisation. [Figure 3 B]
On distal surface of mandibular second molar intermittent cortical perforations were done to facilitate rapid tooth movement. [Figure 3 C]
Discussion
In the present case dentoalvelar distraction was used to accomplish rapid molar mesilation, which helped in reduction of total treatment time, employing an innovative technique by modifying mandibular hyrax appliance. The edentulous space in mandibular right posterior region was four years old. It was decided to close the edentulous space by orthodontic tooth movement of posterior teeth.
Literature was searched to explore techniques to minimize treatment time for management of posterior edentulous space. Numerous surgically invasive procedures for elimination of the cortical bone obstruction to comfort or fast-track mesialization of posterior teeth into edentulous space have been enumerated in history which mainly includes corticotomy. The objective of cortiocotomy is to encourage the demineralization of the cortical bone of the residual alveolar ridge, which is the main barrier in tooth movement.2 Another advantage of corticotomy procedure is initiation of RAP phenomenon, which accelerates physiological bone response.3
The distraction osteogenesis technique in the field of orthodontic tooth movement is utilizatiing the principle of distraction to move a group of teeth or a single tooth, with an aim to reduce the treatment time. Corticotomy procedure was done to expand the alveolar ridge in the mandibular posterior region and accomplish full closure of the edentulous spaces while decreasing the risks associated with removal of the alveolar ridge barrier. The procedure was similar to that used in earlier studies of ridge-split osteotomy, involving bucco-lingual expansion of the cortical bone, as is used commonly in implant dentistry.4
In the present case, similar principle of distraction to move individual tooth was utilized, with the custom-made, rigid, tooth-borne distractor [Figure 4 ]. The modified dentoalvelar distraction device made from mandibular hyrax appliance was helpful in achieving molar mesialization at a frequency of 0.5 mm per day. Complete molar mesilazation was achieved in 15 days [Figure 5 ]. Prasad PN et al. (2018) proposed a modification of maxillary hyrax for maxillary molar protraction. A review of literature does not reveal any documented evidence of similar innovative use of mandibular hyrax for molar mesilazation.
With this modified dentoalvelar distractor anchorage loss was minimized, since the interval of molar mesilazation was too small for movement of the anchorage unit and it was further enhanced by TAD, which was placed between two premolars. The sagittal and vertical anchorage losses were negligible and there were no clinical or radiographical confirmation of the complications, such as root resorption. This distractor should not be used in cases with knife edge ridge and pathological migration.
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