A systematic review of vertical stability for surgical orthodontic treatments
Solano-Hernández B, Antonarakis GS, Scolozzi P, Kiliaridis S. Combined orthodontic and orthognathic surgical treatment for the correction of skeletal anterior open-bite malocclusion: a systematic review on vertical stability. J Oral Maxillofac Surg 2013;71:98-109
Anterior open-bite malocclusions, often treated with a combined orthodontic and surgical approach, are a great challenge for orthodontists during both treatment and retention. The aim of this review was to evaluate the vertical stability of combined orthodontic and surgical treatment of skeletal anterior open-bite malocclusions by using different surgical techniques and fixation. A literature search yielded 9 studies pertaining to vertical stability after combined orthodontic and surgical treatment; all were retrospective, and most were graded as having a low level of evidence. The data from these studies were evaluated based on the type of surgical procedure and the length of follow-up, with a 2-year cutoff to differentiate short-term from long-term follow-ups. There were wide variations in relapse after combined orthodontic and orthognathic surgical treatment for skeletal anterior open bite. Relapses of overbite (>2 mm bite opening) were seen in 16% of long-term follow-ups after LeFort I osteotomy and in 13% of short-term follow-ups after bilateral sagittal split osteotomy, yet no changes were greater than 2 mm after bimaxillary surgery. Increases of the mandibular plane angle (>2°) were evident during the short-term follow-ups after bimaxillary surgery, but only evident during long-term follow-ups after LeFort I osteotomies. Additionally, greater increases in the intermaxillary plane angle and anterior facial height tended to be seen in patients after bimaxillary surgery, compared with other surgical interventions. No conclusions could be drawn from the included studies about the influence of the type of fixation on vertical stability. Long-term skeletal relapse appears to be more prevalent after bimaxillary surgery for correction of anterior open-bite malocclusion, although there is a need for well-designed prospective studies with control groups investigating vertical relapse after various surgical interventions.
Reviewed by Michael Payne
Retention stability randomized controlled trial
Edman Tynelius G, Bondemark L, Lilja-Karlander E. A randomized controlled trial of three orthodontic retention methods in Class I four premolar extraction cases—stability after 2 years in retention. Orthod Craniofac Res 2013 Jan 3 [Epub ahead of print]
Maintaining the results of orthodontic treatment is a challenge despite all the advances in contemporary orthodontics. This randomized controlled trial compared 3 retention protocols: group V-CTC (2-mm vacuum-formed maxillary retainer, bonded mandibular canine-to-canine retainer), group V-S (vacuum-formed maxillary retainer with 0.22-0.34 mm stripping of 10 proximal mandibular anterior surfaces), and group P (prefabricated positioner covering all erupted teeth). The sample included 75 patients treated with 4 premolar extractions and fixed appliances. Their instructed wear time for the vacuum retainers was 22 to 24 hours per day for the first 2 days, followed by nighttime use for 12 months, and 30 minutes during the day and while sleeping for 12 months for the positioner. In the second year, all patients were on an every-other-night schedule. Mean age at the start of retention was 14.4 years. Study casts were obtained before treatment, at debond, and at 12 and 24 months into retention. Little’s irregularity index, intercanine and intermolar widths of the maxilla and the mandible, arch length, overjet, overbite, and body height were measured. Values less than 3.5 mm for Little’s irregularity index were defined as successful for retention. All 3 methods were successful in retaining the treatment results, although there was a significant difference among the protocols with Little’s irregularity index for the groups: V-CTC (0.9) and V-S (1.2) vs P (2.0). The majority of relapse was in the mandibular anterior teeth during the first year of retention with minor changes during the second year. The authors suggested avoiding indiscriminate use of bonded lingual retainers and choosing retention appliances according to the initial diagnosis, cooperation, and oral hygiene.
Reviewed by Manika Patwari
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