Full-mouth rehabilitation of an acromegaly disease patient with removable prostheses: a clinical case report

Acromegaly is a rare disease that can have serious consequences. This disease is not widely known by stomatologists, although cranio-facial manifestations are important and rapid changes in the oral cavity are frequent and sometimes dramatic. The prosthetic management of patients with acromegaly is not easy because it is necessary to wait for the stabilization of the disease. If this is not the case, the bone changes prevent the stability of prostheses over time. Moreover, because of bone remodeling, some treatments are contra-indicated, which limits our therapeutic choices. Through this clinical case, we will focus on the oral manifestations of patients with acromegaly and the method of prosthetic management.


Introduction
Acromegaly is a rare endocrine disease that was first medically described by Nicolas Saucerotte in 1772 [1]. Then, in 1864, acromegaly was described under the name of prosopectasia by the Italian anatomist Andrea Verga. Later on, Pierre Marie in 1889 described the whole clinical picture [2]. This disease is characterized by a chronic and unrestrained hyper-secretion of the growth hormone produced by the pituitary gland after the epiphyseal plate closure at puberty. Its prevalence varies between 2.8 and 13.7 cases per 100 000 people with an annual incidence of 0.2 and 1.1 cases per 100 000 people [3]. Acromegaly is associated with increased morbidity and mortality as well as life quality's limits. Patients often have cardiovascular problems, diabetes mellitus, phosphocalcic disturbances, and lipid metabolism disorders [4]. On the other hand, this disease causes numerous complications as well as significant structural changes in the oral cavity [5]. The dysmorphic syndrome that characterizes acromegaly is dominated by an enlargement of the thorax and a projection of the sternum forward by the proliferation of costochondral joints, an enlargement of the hands and feet, a thickening of the lips and nose, a protrusion of the superciliary arches due to the pneumatization of the frontal sinuses, a mandibular prognathism and an opening of the gonion angle [5]. The dental complications are partially or completely irreversible after the correction of the excess secretion of the GH. This reinforces the idea of getting a diagnosis as soon as possible to avoid or at least to reduce the consequences of acromegaly .In dental literatures; there are very few precise descriptions of the odonto-stomatological and especially the prosthetic management of these patients.   (Figure 2A, Figure 2B). The enlargement of arches was found at mandibular level. At the maxillary level, the ridges were tall, well-formed and covered by a firm and adherent fibro-mucosa with a broad and moderately deep palate. At the mandibular level, the alveolar ridge was moderately high with a firm fibro-mucosa. A prominent macroglossia with the impression of the mandibular teeth on the anterior and lateral edges of the tongue was noted ( Figure 2C).
The residual mandibular teeth were separated by diastema. A generalized recession ranging from 2 to 4mm was found and a first degree of mobility was registered in all residual maxillary and mandibular teeth except the 44 th tooth (third degree mobility). The occlusal examination showed an anterior inverted occlusion ( Figure   2D), a collapsed vertical dimension of occlusion and a lack of the anterior guidance. This clinical examination was completed by an Xray examination ( Figure 3A, Figure 3B); an orthopantomogram (OPG) and a cephalogram were requested. The OPG revealed a ratio radiological crown / radiological root equal to 1 in the maxillary teeth.
This ratio was bigger than or equal to 1 in the mandibular teeth. The cephalometric analysis (Table 1)  Maxillary impression: the maxillary impression was taken from silicones with high and low viscosities according to the Washtechnique without a particular precaution ( Figure 6A).
Occlusal registration: the registration of occlusion for the FPP was made in the centric relationship according to the new VDO ( Figure 6B) and sent to the lab with the corresponding metallic framework shema.
The main maxillary connection was anteriorly and posteriorly cleavaged in order to alleviate the metallic framework. At the lab, the wax sculpture of the infrastructure was made. Millings and guidance plans were planned at this stage using the parallelizer. After FPP metal casting ( Figure 6C), the metal frame was fitted inside the mouth ( Figure 6 D). Thereafter, the technician made the assembly of the ceramic ( Figure 6E).
RPP making: an anatomic-functional impression with a polyether was made ( Figure 7A) to make the metal frame. After fitting the frame in mouth (Figure 7B), the occlusion was recorded for mounting the prosthetic teeth. This laboratory step was specifically delicate. Indeed, the choice of teeth had been important. We had to pick teeth a little wider than those available in dental market. As a result, the lab technician proceeded to CAD-CAM tooth carving ( Figure 7C, Figure   7D) in order to better align the occlusal contacts with the opposing teeth. The posterior prosthetic teeth ( Figure 7E

Discussion
The oral conditions induced by acromegaly had complicated the prosthetic management. Mandibular prognathism, macroglossia, diastema, and malocclusions had been described in the literature as frequent manifestations of acromegaly. The mandibular prognathism, observed in this patient, is often the most striking physical feature of acromegaly [6]. This prognathism results from the appositional growth and hypertrophy of the condylar cartilage, which is aggravated by the pressure exerted by the tongue. The study by Künzler et al. [7] showed that 16 to 57% of the acomegalic patients had a prognathism with an average protrusion of the mandible of 9.3 +/-3.4mm. As for the maxillary bone, most authors agree that it does not undergo deformities in acromegaly [8]. Macroglossia is considered a possible cause of mandibular prognathism. Indeed, it has been suggested that an increase in soft tissue volume induces an osteogenic reaction in bone growth sites [6]. Class III occlusion is the most typical feature and its frequency is between 25% to 77% [7]. Hermann et al [9] found the anterior cross Page number not for citation purposes 4 occlusion in 48% of cases and end-to-end occlusion in 56% of cases.
The presence of diastema is observed in 93.75% of acromegalic patients, and is caused by an increase in the mandibular volume [10], pressure of the tongue and malocclusion. There is an increase in tooth mobility especially in the anterior teeth of the lower jaw [8,10]. Dental mobility is caused by several factors: severe occlusal trauma due to class III malocclusions, excessive chewing force resulting from the exaggerated mandibular enlargement and muscular hypertrophy and the pressure of the tongue on teeth [10]. Acromegaly can also affect the temporomandibular joint; growth hormone promotes endochondral and periosteal bone growth. The growth of cartilage on the condyle may cause irregularities in shape. For acromegalic patients seeking prosthetic rehabilitations, the therapeutic decision depends on several clinical parameters, the benefit, the cost, the safety ratio and the feasibility of the treatments taken into consideration.
Ideally for this patient, it was necessary to consider an orthodonticsurgical treatment for the correction of the skeletal and the dental class III followed by a fixed or removable implant-supported prosthetic rehabilitation. These interventions should only be considered when growth hormone levels have been stabilized. In this case, the patient had not yet had a good regulation of GH secretion.
Thus, the choice of one of these proposals was not retained because of the significant bone remodeling. The complexity of the treatment was due to the absence of the orthodontic-surgical preparation.
Therefore This type of assembly reserves the needed space for the tongue.
However, it often leads to poorly controlled premature contact.
Balancing in deduction is difficult and cheek bites will be common. In addition, interferences on the non-working side cause and amplifie bone resorption phenomena. To cope with the problem found during the assembly of the prosthetic teeth, it was more judicious to set up the dental units in the prosthetic corridor recorded with piezography for a better compromise of efficiency and comfort.

Conclusion
The mouth is the seat of many anomalies' manifestations, including acromegaly. These anomalies can lead dentists to become actors for earlier detection of the disease. Odontological management of acromegaly requires a careful work by dentists who must be aware of the existence of this rare disease. Dentists' collaboration with other medical specialties will definitely optimize the longevity of the results obtained by the established therapy.

Competing interests
The authors declare no competing interests.

Authors' contributions
All the authors have read and agreed to the final manuscript.