A large number of adults seek orthodontic procedures to improve dental defects. There are many biological and clinical differences between orthodontic treatments in adults and paediatric patients. One of this is growth. Growth is almost insignificant in adults compared to children. Chances that hyalinisation will occur during treatments is substantial in children as opposed to adults. Moreover, biologic mechanisms of bone remodeling are much slower in adults than in children. Ultimately, adults are more predisposed to periodontal complications since their teeth are in solid alveolar bone. These considerations make orthodontic treatment in adults quite challenging. The development of corticotomy-assisted orthodontic treatments offers solutions to some limitations in orthodontic treatments in adults.
A bit of history
Corticotomy origins from orthopaedic surgery and goes back to the early 1900s. In 1892, it was first described as a technique in the cortical plates surrounding the teeth to mobilise dentition.
Köle introduced a surgical procedure involving both osteotomy and corticotomy to accelerate orthodontic tooth movement. This is based on the principle that teeth move faster when the resistance exerted by the surrounding cortical bone is reduced via a surgical procedure. This theory was validated by several clinical reports.
1. Resolve Crowding and Shorten Treatment Time
Corticotomy and osteotomy are used in orthodontics primarily to resolve crowding in a shorter period of time. Several authors have described cases in which moderate and severe crowding was treated without extraction by corticotomy or osteotomy-assisted orthodontics and in shorter periods of time. Corticotomy has proven to reduce treatment time to as little as one-fourth the time usually required for conventional orthodontics. A clinical trial led by Hajji  looked at the effects of resolving mandibular anterior dental crowding by comparing non-extraction (n = 30), extraction (n = 34), and corticotomy-facilitated non-extraction (n = 20) orthodontic treatments. The mean active treatment time for the corticotomy-facilitated group was 6.1 months, versus 18.7 months required for non-extraction orthodontics and 26.6 months for extraction therapy.
2. Accelerate Canine Retraction after Premolar Extraction
Canine retraction after premolar extraction is a lengthy step during the extraction stage of orthodontic treatment. Corticotomy accelerated canine retraction in animal studies resulting in a faster retraction when compared to conventional orthodontic retraction.
3. Enhance Post-Orthodontic Stability
Stability after orthodontic treatment may be a challenge. Corticotomy-assisted orthodontics favours stability due to the increased turnover of tissues adjacent to the surgical site.
4. Facilitate Eruption of Impacted Teeth
Surgical traction of impacted teeth, especially the canines, is a frustrating and lengthy procedure. A study by Fischer showed that under the same periodontal conditions, the corticotomy-assisted approach produced faster tooth movement during traction of palatally impacted canines compared to conventional canine traction methods at the end of either treatment.
5. Facilitate Slow Orthodontic Expansion
Few successful techniques are available for the treatment of maxillary arch constriction and tend to be aggressive” these include surgically-assisted rapid palatal expansion and slow palatal expansion. Yen et al. reported a cleft patient with palatal constriction in the upper arch who was treated via corticotomy-assisted expansion after surgical closure of a palatal fistula. Corticotomy assisted expansion is an effective technique for the treatment of maxillary transverse deficiency in adults. It is thought to provide greater stability and better periodontal health than conventional expansion.
6. Molar Intrusion and Open Bite Correction
Corticotomy-assisted orthodontic treatment has also been used in the treatment of severe anterior open bite in conjunction with skeletal anchorage. Moon et al. achieved sufficient maxillary molar intrusion (3.0 mm intrusion in two months) using corticotomy combined with a skeletal anchorage system with no root resorption and with no patient compliance required. Olivieria et al. reported 4 mm of molar intrusion in 2.5 months using corticotomy in one patient and 3 to 4 mm in 4 months in another patient.
7. Manipulation of Anchorage
Corticotomy-assisted orthodontic treatment was used in the treatment of bimaxillary protrusion as an adjunct to manipulate skeletal anchorage without any adverse side effects in only one-third of the regular treatment time. It was also used to achieve molar distalisation.
Contraindications and Limitations
Patients with active periodontal disease or gingival recession are not good candidates for corticotomy-assisted orthodontic treatment.s In addition, these treatments should not be considered as an alternative for surgically-assisted palatal expansion or in cases where a bi-maxillary protrusion is accompanied with a gummy smile. These cases might benefit more from segmental osteotomy.
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Note: the image of this post was taken from "Using Surgically Facilitated Orthodontic Therapy as a Tool for Optimal Interdisciplinary Results" Richard D. Roblee, DDS, MS; Scotty L. Bolding, DDS, MS; and Jason M. Landers, DDS, MS. February 2013 Course Parkell Online Learning Center. (accessed on 8th July 2018)