Amelogenesis imperfecta can have different inheritance patterns depending on the gene that is altered. Mutations in the ENAM gene are the most frequent known cause and are most commonly inherited in an autosomal dominant pattern. This type of inheritance means one copy of the altered gene in each cell is sufficient to cause the disorder.
Recent genetic studies suggest that the cause of a significant proportion of amelogenesis imperfecta cases remains to be discovered.
Treatment of AI is not only important for functionality but also for patient psychosocial health and esthetics. Although AI is a low prevalence condition, affected patients suffer a great number of clinical problems that affect their quality of life. In most cases the partial or total absence of enamel is associated with pain caused by thermal end chemical stimuli. Reduced crown due to incomplete eruption results in reductions to both masticatory function and occlusal vertical dimension. Considering all potential clinical complications and psychosocial affects, precise and early diagnosis of AI and proper treatment is vitally important for every patient.
Treatment may range from no intervention (mild cases) to full or partial mouth restoration (moderate and severe cases). In cases of severe penetrance of the hypomature or hypocalcified type/impacted teeth it may be most cost effective to edentulate the unrestorate dentition and rehabilitate with implant supported restorations from the outset of skeletal maturity [12]. The absence and shape of teeth and problems associated with enamel (such as sensitivity, staining and roughness) can be of major psychological and functional concern to AI patients. As such, the principal goals of the treatment plan should include pain managements, prevention, stabilization, restoration of any defects, and maintenance of aesthetics and function [13].
Modern management of AI requires a multidisciplinary approach utilizing a full armamentarium of disciplines [9, 14–16]. The management of teeth begins in the primary dentition, followed by the secondary dentition as the teeth erupt. Treatment protocols may change according to the clinical features of AI and are dependent on the absence/form of existent teeth. Management will also vary according to the needs of the patients and proposed treatment plans may consist of: 1) Surgical exposure followed by orthodontics extrusion of teeth and a restorative approach; 2) removable acrylic over denture; 3) cast overlay denture; or 4) implant insertion and fix prosthesis [15, 17].
The patient’s main concerns were difficulty in chewing and esthetics. Considering the patient’s relatively young age we aimed for a more stable outcome; Le fort I distraction osteogenesis would be more effective than classical Le Fort I advancement. In this case, the quality and volume of bone represented additional challenges to manage. Since patient didn’t accept any autogenic bone replacement and any further operations, it was exceedingly difficult to identify a proper and suitable location for a dental implant to support the prosthesis.
We have proposed that correction of the interalveolar relationship between the maxilla and the mandible can be achieved with distraction osteogenesis through orthognathic surgery and insertion of dental implants. Although insufficient bone volume allowed only a limited number of implants (and therefore prosthetic planning could not be extensive), the patient was satisfied with the final result, both esthetically and functionally.
The use of dental implants in edentulous patients provides safety and function in oral rehabilitation. For rehabilitation to be possible patients require adequate bone mass and suitable alveolar bone. These features can be achieved by augmenting bone graft (Onlay bone graft or inlay bone graft into the sinus). Another possibility, is to produce adequate bone mass and reposition alveolar bone by arranging the antero-posterior position of maxillary bone by Le Fort I down-fracture and inter-positional bone grafts. Some authors have used distraction osteogenesis in the severely resorbed maxilla, which can improve alveolar position and facilitate the jaw into a more favorable position [18, 19].
In most such those cases, Le Fort I distraction using an internal device is a stable and convenient option of correction. Indeed, distraction osteogenesis has been shown to be an accepted method of correcting sagittal discrepancies in cases of dentate and edentulous maxillary hypoplasia with stable long term results [20, 21]. However, there are only a few available reports in which this method is used to correct sagittal discrepancies in edentulous patients [21–23].
In atrophied maxilla, a lack of supporting bone can compromise the insertion of endoosseos implants. In cases of inadequate height and width of the maxillary alveolar crest a sufficient recipient site is required.
The benefits of distraction include avoidance of bone grafting and donor side morbidity, as well as its availability for use in surgery on younger patients and concurrent expansions of soft tissue envelops [24].
Treatment plans for AI are dependent on many factors including patient age, type and severity of disorder and intraoral conditions. Treatment should begin at childhood and continue into adolescence and consist of an interdisciplinary approach including periodontal, orthodontic, prosthodontics, surgical and restorative methods.
We report an orthognathic procedure for AI using Le Fort I distraction osteogenesis, in which a large difference was achieved between the initial and final profile of the upper lip, resulting in a greatly improved facial profile supported by prosthesis, with immediate improvement in chewing function and aesthetics.
It is often difficult to achieve stable and satisfactory results in the treatment of AI patients. This is exasperated in AI patients with rerouted maxilla. In such cases, pre-surgical orthodontics is often unachievable because of absence of teeth or lack of crown height and poor enamel condition.
Our treatment strategy attempts to serve patient needs, achieving function and esthetics while also minimizing the risk of reconstruction failure. When long term stability is in question, risks and benefits of the treatment plan should be thoroughly evaluated to achieve the best possible results according to the specific needs of each patient.
Consent
Written informed consent was obtained from the patient for publication of this case report and any accompanying images. A copy of the written consent is available for review by the Editor-in-Chief of this journal.
