2019, Number 4
Correction of a maxillary hypoplasia with a Le Fort I osteotomy. Clinical case report
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Language: English/Spanish [Versión en español]
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ABSTRACT
Introduction: A 13-year-old patient is treated in the Orthodontic Clinic of the Autonomous University of Guadalajara; the patient's chief complaint was "I don't like my smile and I want you to fix my teeth". She was diagnosed with a skeletal class III malocclusion due to maxillary hypoplasia causing a mid-face deficiency, with no overjet or overbite, deviated dental mid-line, based on the above, an orthodontic-surgical treatment was chosen. Objectives: Establish class I canine relationship, class II functional molar relationship, occlusal stability, improve facial and dental esthetics. Clinical case report: Once the orthodontic and surgical treatment was accepted, the treatment was divided into three phases; the pre-surgical phase started with the placement of MBT slot 0.022" orthodontic appliances, extractions of upper first premolars, decompensation was achieved once the upper incisors were placed in their ideal position. The surgical phase consisted of a 3 mm maxillary advancement and a 4 mm descent with a Le Fort surgery. In the post-surgical phase, dental detailing and settlement were performed. Results: We obtained a skeletal class I, class I canine, and bilateral class II functional molar relationship, in the post-surgical phase, generating in the patient a better perception of herself. Conclusions: We met our goals, the orthognactic surgery enable the efficacy of orthodontic treatment, dental functionality and patient's positive self-perception.INTRODUCTION
Class III malocclusion can be associated with pure mandibular prognathism or maxillary hypoplasia or a combination of both. This means that there is possible anatomical heterogeneity in this type of malocclusion, as either jaw can be affected in sagittal length or in the relative position of both. Familial aggregation studies suggest that heredofamilial and environmental factors play a substantial role in the aetiology of class III malocclusion.1 Most researchers agree that various combinations of dental and skeletal elements may be involved in the production of a class III malocclusion. In fact, every component of the craniofacial complex has at one time or another been implicated as a causative factor.2 In a literature review, multiple authors report that measurements of the craniofacial region are divided into four groups based on different anteroposterior criteria: maxillary skeletal position, maxillary dental position, mandibular dental position and mandibular skeletal position.2 Regarding gender differences in class III malocclusions, Baccetti et al.3 reports that at age 13, the craniofacial measurements between males and females are different, with the female group presenting short anterior cranial bases, short mandibular mid-thirds and lengths, short upper and lower anterior facial heights and more proinclined upper incisors, as well as lips in a more retrusive position in relation to the E-plane.3,4
Maxillary deficiency in the maxillary region may be associated with a midface deficiency, which is corroborated by the contour of the malar bone, orbital ridge, and suborbital area, which can be described as flat.5 Since the deficiency of the basal bone is reflected in the soft tissues, causing an unfavourable effect on facial aesthetics that can affect the patient's self-esteem. The literature reports that class III caused by maxillary growth deficiency should be treated as early as possible as it can have a positive effect on facial aesthetics and can redirect this unfavourable growth in the maxilla.6-8
Anterior crossbites and mild skeletal class III malocclusion in a mixed dentition can be corrected with various treatment approaches, including removable appliances, fixed appliances, chin braces, and face masks. When untreated, anterior crossbites can be associated with a variety of complications, such as gingival recession of the lower incisors, incisal wear, and worsening of the growth pattern.9 In 1987, McNamara7 presented a case report and used a fixed hyrax-type expansion appliance in conjunction with a face mask in patients with a deficiency of the maxilla. In the 1990s, several scientific studies clarified the effects of maxillary protraction in the correction of skeletal class III malocclusions with a maxillary deficiency.10
When the orthodontic problems of the patient are so severe that even growth modification and camouflage are not a good solution, the only possible treatment is surgical realignment of the jaws or repositioning of the dentoalveolar segments.11 The 60s was a decade of breakthrough in maxillary surgery, American surgeons began to modify maxillary surgery techniques developed in Europe, culminating in the development of the Le Fort I technique with descending fracture that allowed repositioning of the maxilla in all three planes of space.12 The following is the case of a 13-year-old female patient of skeletal class III due to maxillary hypoplasia corrected with MBT appliances and Le Fort I surgery.
CLINICAL CASE REPORT
Diagnosis and (aetiology) treatment plan: 13-year-old female patient comes to the Orthodontic Specialty Clinic of the Autonomous University of Guadalajara, because she wants to have her teeth fixed. The patient has a mesofacial facial biotype with a straight profile and neutral growth, with a short upper third and an enlarged middle and lower third, thick lips, with a closed nasolabial angle, short upper lip, lip incompetence, presents a low symmetrical smile with coincident facial and dental midline, shows six teeth in the upper arch, no buccal corridors, incisal edges do not coincide with the smile arc, no gingiva when smiling and shows an edge-to-edge bite (Figure 1A).
In the intraoral analysis the patient presents quadrangular upper dental arches and an ovoid lower dental arch, with dental organs 13 and 23 in subocclusion and dental organ 13 out of arch, anterior superior and anterior inferior crowding with gyroversion of dental organ 41, edge-to-edge bite, non-coincident dental midlines, right and left molar class I, left canine class I and right canine class not established, overjet and overbite of 0 mm (Figure 1B), with a left Spee's curve of 1. 5 mm and a Spee curve of 0 mm (Figure 2).
Panoramic radiograph (Figure 3A) shows dental organs 18, 28, 38 and 48 included, healthy condyles with patent airways.
Cephalometrically it was diagnosed as a skeletal class III due to maxillary hypoplasia and mandibular prognathism, lower dentoalveolar retroinclination with neutral growth in the Steiner cephalometry done digitally in Dolphin version 9.0 (Figure 3B and Table 1).
Treatment goals: improve patient profile. Achieve bilateral canine class I and functional molar class II, alleviate upper and lower crowding, correct overjet, overbite and dental midline.
Treatment alternatives: upper palatal expansion with a hyrax-type disjunctor, facial mask with Hyrax-type disjunctor or dentoalveolar compensation with lower second premolar extractions were considered.
Treatment plan: as soon as it was decided to treat the patient orthodontically and surgically, a three-stage protocol was established; pre-surgical orthodontic stage, surgical stage and a post-surgical orthodontic stage. MBT slot 0.022" × 0.028" appliances with 0o torque were placed in canines, in order to free the crowding, extractions of upper first premolars were made, as well as lower dentoalveolar proinclination to perform pre-surgical decompensation. Le Fort I surgery was performed, followed by the postsurgical orthodontic stage with a final retention stage.
Treatment progress: treatment began with the placement of upper and lower MBT slot 0.022" × 0.028". The alignment and levelling phase began with 0.012" nickel titanium (NiTi) archwires placement, and extractions of 14 and 24 teeth organs. Next, 0.014" NiTi archwires were placed with retro-ligation activation in the upper canines, later on 0.016" steel archwires were placed in the upper and lower archwires and, open-coil was placed in the lower archwire to create space for tooth organ 41. To maintain space for tooth 41, 0.019" × 0.025" NiTi upper arch and 0.014" NiTi lower arch were placed with a bypass, and then tooth 41 was included. Subsequently, 0.016" NiTi arch and 0.019" × 0.025" NiTi lower arch were placed, continuing with 0.019" × 0.025" steel (SS). Crimpable hooks were punctured in the arch in both arches for eight months to complete the decompensation phase and the patient was asked to take a lateral skull X-ray to confirm the location of the incisors in their bony bases (Figure 4). Once the lower incisor was stable, Le Fort I surgery was performed, in which maxillary advancement of 3 mm and a maxillary descent of 4 mm were done, making a clockwise rotation. Two L-shaped titanium plates were fixed with four 1.5 mm screws in each system (Figure 5A). Post-surgery, 0.019" × 0.025" braided upper and lower archwires were placed with elastics in triangular seating and boxed in anterior teeth, for two months (Figure 5B). Brackets were removed, Essix 0.030" was placed, afterwards an upper and lower circumferential retainer was placed, fixed in the lower 5 to 5 with braided ligature 0.010" (Figure 6).
Treatment results: the objectives were met. Skeletally, skeletal class I was obtained due to protrusion of the upper jaw. Facially, a straight profile was obtained with a correct position of the upper lip and a decrease in the nasolabial angle. Dentally, class I canine and class II functional molar centered the midlines, therefore, correcting the overjet and overbite (Figure 7). The patient was referred to the maxillofacial surgery department for extractions of the third molars. Significant changes in facial profile and cephalometric values were observed in the overjet (Figure 8 and Table 1).
DISCUSSION
The aesthetic zone is important for the success of dentofacial harmonisation. The clinician should be able to incorporate the facial and dental assessment in a concise format to identify and then guide the patient toward facial reconstruction. A correct diagnosis begins with the facial and skeletal soft tissues, followed by an intraoral inspection, its relationship to the lips and respiratory conditions. Facial skeletal evaluation may indicate maxillary or mandibular dysmorphia, including vertical or horizontal skeletal deformities. Although facial beauty is a subjective concept, as clinicians we must have certain objective means to aid in the diagnosis and treatment plan. Panossian et al.13 emphasizes the importance of these means such as photography, cephalometry and individual tooth position. In order to achieve all of the above, this same protocol was used in the present study, coinciding with the concept of aesthetics, which is so important to achieve in a treatment plan.
In the present clinical case, we were able to witness how the patient was motivated by the proposed plan and after the surgery, she had a radical positive change. Rizzato et al.14 stated that patients with dentofacial deformities have a disadvantage in society due to their low self-esteem, low levels of security and associated psychological problems. We agree with Cadogan et al.15 that patients who decide to continue with this long process are more motivated to make changes and improve their quality of life.
The decision between orthodontic camouflage and orthognathic surgery remains a challenge for orthodontists. Class III patients who refuse orthognathic surgery have been treated aggressively with brackets of different torques, class III elastics, extractions and multi-loop archwires. Orthodontic camouflage consists of a combination of protrusion of the upper incisors and retraction of the lower incisors. These adverse effects can lead to excessive proinclination of the upper incisors, extrusion of the upper molars and instability during retention. Since the retraction of the lower incisors increases the relative prominence of the chin, this may worsen the profile rather than improve it.9 Taking into account the facial and skeletal limits of the patient, orthodontic camouflage may be the best option for specific patients, unlike ours. For example, the case presented by Park et al,16 the patient had a less sagital discrepancy, greater lower proinclination and a less unfavourable profile contrary to our patient's characteristics and therefore a surgical decision was made instead of camouflage as Rizzato et al14 did.
Thanks to all the benefits of the surgery, we agree with Janson et al.17 that the maxillary advancement helped to improve the support of the upper lip, there was better projection of the soft tissues of the middle third and it favourably improved the profile of our patient. Surgical advancement of the maxilla established a good anteroposterior relationship between the mandible and the maxilla, and improved the exposure of the upper incisor.
Due to the above, the best option for the patient was a maxillary advancement with Le Fort I surgery as it helped to cephalometrically improve her ANB, improved dentofacial harmony and avoided potential damage to the periodontium by making dentoalveolar compensations. Once it was decided to perform a maxillary advancement by means of Le Fort I orthognathic surgery, we proceeded with pre-surgical orthodontics because we agree with Proffit et al.18 on the importance of dental alignment before surgery. As it can be complicated to accommodate both jaws in the ideal position when there are dental irregularities which can cause interferences in the new maxillary position, that is why we started with alignment and levelling as this stage is key for the success of the pre-surgical planning.
Another guideline we took into account to maximize the stability of the post-surgical occlusion was to keep all the dental organs within their bony bases during the decompensation phase. Unlike orthodontic camouflage as performed by Park et al.,16 one of the disadvantages is that the teeth remain outside their bony bases and their IMPA was greatly diminished.
CONCLUSIONS
Successful surgical treatment of skeletal class III malocclusions begins with soft tissue diagnosis taking into account the profile, lip projection and then intraoral diagnosis. We achieved of our proposed goals thanks to the orthognathic surgery that allowed the effectiveness of orthodontic treatment, functionality, skeletal class I, better harmonisation of the profile, and a favourable relationship between overjet and overbite, and the harmonisation of the facial profile contributed to a positive self-perception of the patient.
REFERENCES
AFFILIATIONS
1 Egresada de la Especialidad en Ortodoncia. Universidad Autónoma de Guadalajara. México.
2 Alumna de la Especialidad en Ortodoncia. Universidad Cuauhtémoc. Plantel San Luis Potosí. México.
3 Cirujano Maxilofacial. Clínica de Cirugía Maxilofacial del Centro Médico Puerta de Hierro. Zapopan, Jalisco.
4 Profesor de la Especialidad en Ortodoncia. Departamento de Clínicas Odontológicas Integrales. Centro Universitario de Ciencias de la Salud. Universidad de Guadalajara. México.
CORRESPONDENCE
Jacqueline Adelina Rodríguez-Chávez. E-mail: jacqueline.rchavez@academicos.udg.mxReceived: Marzo 2020. Accepted: Junio 2020.