Surgical-orthodontic retreatment of a severe skeletal Class III malocclusion following an orthodontic camouflage

ABSTRACT Introduction: Class III malocclusions are some of the most difficult occlusal anomalies to be treated. Some patients with this condition may require orthognathic surgery, while others may be treated with dental camouflage. Proper patient assessment and selection remains critical in order to achieve favorable results. Objectives: This report outlines the case of an 18-year-old male who sought retreatment for a severe skeletal Class III dentofacial deformity after undergoing orthodontic camouflage treatment involving mandibular arch extractions. A treatment plan comprising dental decompensation and orthognathic surgery was implemented in order to achieve optimal facial and occlusal results. Results: After 28 months of treatment, skeletal and dental correction was achieved and facial features were significantly improved. The orthognathic surgery required a 20-mm sagittal maxillomandibular skeletal correction, combined with a 4-mm correction of the midlines and a 2-mm impaction of the maxilla. Conclusion: Dental compensation may be a risky treatment alternative for severe dentoskeletal discrepancies. In these patients, orthodontics combined with orthognathic surgery is the recommended treatment option.

Martino F, Peña M, Joubert R -Surgical-orthodontic retreatment of a severe skeletal Class III malocclusion following an orthodontic camouflage

INTRODUCTION
When treating Class III dentofacial deformities in patients with little or no further skeletal growth potential, there are two possible treatment options: orthodontic camouflage or orthodontics combined with surgical repositioning of the jaws. 1,2,3 Orthodontic camouflage is viable when treating patients with mild to moderate dentoskeletal discrepancies with acceptable facial aesthetics. [4][5][6][7] However, in patients with severe skeletal discrepancies, a combined surgical-orthodontic approach is the preferred method in order to improve facial aesthetics and achieve a stable occlusion. [8][9][10] Camouflage orthodontic treatment for severe Class III skeletal discrepancies requires excessive compensatory tooth movements to achieve acceptable results, which may end up leading to adverse aesthetic side effects and other problems such as root resorption, periodontal disease and poor stability. 11 Furthermore, the patient could grow out of the range of successful camouflage treatment, leading to the need for a surgical correction. 12 If the compensatory treatment plan includes the irreversible step of extracting mandibular premolars, additional space management issues may arise during the pre-surgical orthodontic phase of the retreatment.
Martino F, Peña M, Joubert R -Surgical-orthodontic retreatment of a severe skeletal Class III malocclusion following an orthodontic camouflage 5 In this article, the corrective retreatment of a patient with a severe dental and skeletal Class III is presented. The case previously involved an unsuccessful orthodontic camouflage treatment with extraction of two mandibular premolars. were also observed (Table 1). Additionally, a transverse asymmetry due to combination of a rotation of the maxilla (2 mm to the right) and the mandible (2 mm to the left) was found.     In the panoramic radiograph, signs of root resorption were observed in the maxillary incisors, and a mild horizontal bone loss was detected in the mandibular incisors.

TREATMENT OBJECTIVES
In order to correct the problems identified in this patient, the following objectives were set: buccal movement of the mandibular incisors, to achieve proper uprighting; mandibular setback combined with the advancement and impaction of the maxilla, to improve facial esthetics, achieve dental correction, and enhance incisor display in the smile. Lastly, mandible and maxilla alignment, to correct dental and facial midlines.

TREATMENT ALTERNATIVES
After reviewing the diagnostic findings, a dental compensatory treatment was discarded, due to the skeletal nature of the Class III deformity. It was concluded that a non-compensatory treatment approach was necessary and consequently, a com- Pre-surgical records were obtained two weeks prior to surgery, and at the same appointment hooks were placed on passive 0.019 x 0.025-in stainless steel archwires that had been in place for more than six months (Figs 6-8). The orthognathic surgery consisted of 8-mm maxillary advancement with a 2-mm rotation to the left and a 2-mm impaction, combined with 12-mm A comparison between the pre-surgical and final cephalometrics shows that the ANB angle was normalized, increasing from -12.1º to 1.6º. The 8-mm maxillary advancement resulted in a 3º increase of the SNA angle (from 84º to 87º), and the 12-mm mandibular setback induced a 10.7º decrease of the SNB angle (from 96.1º to 85.4º) (Fig 13).    Temporary fiber-reinforced ceromer-based adhesive bridges were bonded to replace the missing lower premolars.
One year after debonding, the results were stable and the patient was pleased with his facial and occlusal outcome (Fig 14).
Martino F, Peña M, Joubert R -Surgical-orthodontic retreatment of a severe skeletal Class III malocclusion following an orthodontic camouflage 16

DISCUSSION
Camouflage Class III treatment usually relies on the extraction of mandibular premolars to correct the anterior crossbite and disguise the skeletal discrepancy. This treatment approach will typically require an excessive lingual inclination of the mandibular incisors, which can often make the chin appear even more prominent, resulting in an unaesthetic outcome. 13 Other complications may include root exposure by resorption of the cortical plate, with subsequent gingival recession and fremitus. 14,15,16 A study by Kerr et al. 17 concluded that orthodontic compensation can effectively camouflage the skeletal and dental aspects of the malocclusion if initial ANB is greater than -4.5º and mandibular incisor angulation is greater than 83º. In this case reported, the patient presented for retreatment with an ANB of -11.5º and mandibular incisor angulation of 59º, which combined with poor facial aesthetics, clearly established the need for a surgical-orthodontic retreatment. In order to allow adequate surgical movements, mandibular incisor uprighting was critical; therefore, space reopening in the mandibular arch was necessary during presurgical orthodontics. Options to move mesially the entire mandibular dental arch were considered, but rejected due to the amount of movement required.
Long term stability for this case is a concern, due to the extreme surgical movements that were necessary to correct the skeletal discrepancy in the sagittal plane (8.0-mm maxillary advancement and 12.0-mm mandibular setback). According to a systematic review by Mucedero et al, 18 bimaxillary surgery for Class III correction will be stable when the maxillary advancement is less than 5 to 6.0 mm, and the mandibular setback, less than 7.0 mm.
Looking at this case retrospectively, the camouflage treatment negatively affected the profile, made presurgical orthodontics more complex, and created the need for permanent restorations. Undergoing a retreatment had a negative psychological impact on the patient, due to undesirable results, time consumption and financial burden. A more careful treatment planning based on an accurate growth analysis and realistic goals may have provided enough information to delay the treatment until the patient had stopped growing and surgery could have been performed.
The study of treatment difficulties, such as those presented in this case report, provides a rare opportunity to gain perspective and aim towards an improvement in the quality of care we provide to our patients. 19 Inexperience or lack of training are commonly attributed as causes for complications and unfavorable outcomes. Nevertheless, even orthodontists with Martino F, Peña M, Joubert R -Surgical-orthodontic retreatment of a severe skeletal Class III malocclusion following an orthodontic camouflage 18 vast experience and adequate training may also expose their patients to some degree of unintended irreversible damage.
In such cases, limited time for diagnosis and treatment planning due to overcrowded offices may play a part. 20

CONCLUSIONS
Orthodontics combined with orthognathic surgery is the recommended treatment option for achieving a stable occlusion and facial esthetics in non-growing patients with severe Class III dentoskeletal discrepancies. When considering camouflage treatment for growing patients with this condition, a careful diagnosis is essential in order to develop a customized goal-oriented treatment plan that considers tooth movement limitations, facial characteristics and remaining growth.
The presented case highlights the adverse effects that compensatory treatment may have in growing skeletal Class III patients, resulting in the need for a second treatment, combining orthodontics and orthognathic surgery, to achieve optimal treatment results.