Palatal Augmentation Prosthesis after Glossectomy: A Case Report

Partial glossectomy, often required in the treatment of tongue cancer, results in significant functional impairment affecting speech, swallowing and chewing. These sequelae are particularly challenging to manage in edentulous patients and/or those who have undergone partial mandibulectomy. The palatal augmentation prosthesis is a relevant prosthetic solution that allows the restoration of tongue-palate contact and compensates for the loss of tongue mobility by morphological adaptation of the prosthetic palate. Using a clinical case, this article outlines the key steps in the prosthetic rehabilitation of a fully edentulous patient who underwent partial glossectomy, highlighting the importance of a multidisciplinary approach and a rigorous technical protocol tailored to the anatomical and functional specificities of each case.

Introduction

Oral cancer is becoming increasingly common and represents a major public health problem in many countries. In Morocco, a total of 810 new cases were recorded between 2013 and 2017, corresponding to a crude incidence of 4.4 per 100,000 in men and 3.1 per 100,000 in women.

Cancers of the mouth, tongue, and lips accounted for 1% of all sites and sexes combined [1]. The tongue is composed of 17 muscles, which provide it with great mobility to perform its functions of mastication, swallowing, suction, and phonation [2].

In accordance with the National Comprehensive Cancer Network (NCCN) guidelines, the surgical excision of primary oral tongue cancer is recommended, with the procedure guided by the tumour’s location, depth of invasion, and imaging findings. This approach may or may not involve neck dissection, followed by adjuvant treatment, which may include radiation and/or systemic therapy. This treatment approach is considered the standard of care [3].

Surgical resection of the tongue can range from partial to total glossectomy, depending on the extent of the tumour. Post-operative sequelae are frequently severe, impacting oral and phonatory function, as well as the patient’s aesthetic and psychological well-being.

The tongue plays a crucial role in phonation, food bolus management, and saliva control. Following surgical resection, significant functional deficits occur, including dysphagia, impaired phoneme articulation, salivary incontinence, and difficulty swallowing. These deficits can lead to a decline in quality of life, emotional distress, and an increased risk of social isolation [4].

A multidisciplinary approach involving various specialists—maxillofacial surgeon, maxillofacial prosthetist, physiotherapist, and psychologist—is essential to restore impaired function and provide psychological support to patients following lingual resection surgery.

Prosthetic rehabilitation with a palatal augmentation prosthesis combined with speech therapy is a simple and effective solution to improve phonation, swallowing, and quality of life in these patients [5].

A palatal augmentation prosthesis is a maxillary removable prosthesis, either partial or total, designed to improve phonation and swallowing in patients with lingual abnormalities, such as paralysis or following a glossectomy [6].

Its design is characterised by a modification of the palatal part of the prosthesis, which allows the palatal arch to be prosthetically lowered. This adjustment facilitates the contact of the tongue with the palate and compensates for the reduced mobility of the tongue. This approach significantly improves phonation and swallowing [4].

Clinical Case

A 70-year-old patient presented for prosthetic rehabilitation of his complete edentulism. His medical history revealed a previous surgery for the excision of a squamous cell carcinoma located on the right marginal area of the mobile tongue, followed by external transcutaneous radiotherapy with a dose of 70 Gy (Fig. 1).

Fig. 1. Extra-oral view.

The patient wears an old complete removable prosthesis, made before the resection surgery, and reports speech difficulties that manifest as incomprehensible speech, making it difficult to communicate with others. He also reports feeding difficulties due to swallowing problems associated with the disruption of normal tongue support.

The extra-oral clinical examination reveals a slight asymmetry of the labial commissures, accompanied by a sagging on the side that underwent resection. Furthermore, the patient exhibited symptoms of xerostomia and exhibited a reduced mouth opening, both of which are likely consequences of the radiotherapy treatment.

Intra-oral clinical examination reveals a partial right glossectomy extending beyond the midline of the tongue, accompanied by a non-interrupting right partial mandibulectomy. The surgical site is well healed, without pain or bleeding (Fig. 2).

Fig. 2. A partial right glossectomy with non-interrupting mandibular loss of substance.

Examination of the old prostheses revealed prosthetic maladjustment due to changes in the contact surface following lingual resection surgery associated with an uninterrupted partial mandibulectomy.

A complete removable supra-implant prosthesis was initially proposed as the preferred option. However, the patient refused to undergo further surgery.

We therefore decided to replace his total removable dentures. The prosthetic procedure was carried out in several successive stages. The maxillary prosthesis was fabricated using a conventional approach with some adaptations specific to the irradiated area. The primary impression was made with a non-compressive material, in this case, irreversible hydrocolloid. For the secondary impression, polyether was used instead of Kerr paste. This modification takes into account the fragility of the tissues after radiotherapy, as the use of Kerr paste could lead to lesions or burns. A single-stage global impression was performed using polyether (Fig. 3).

Fig. 3. Maxillary impression.

In the mandible, a number of problems have been identified: limited mouth opening after irradiation, dry mouth, reduced support surface with a flat mandibular ridge that compromises retention and stabilization of the prosthesis, and a thin and fragile mucosa. It is therefore essential to implement a rigorous protocol to ensure proper integration of the prosthesis.

The design began with a primary impression made with an irreversible hydrocolloid. Special care was taken to capture areas of the oral floor to ensure accurate reproduction. Adjustments to the impression tray may be necessary to accommodate the anatomical features of an operated mandible.

The edges of the impression are then reduced, dried, coated with adhesive, and relined with a liquid alginate.

In cases where the mouth opening is severely restricted, the use of silicone is recommended. An impression tray can be moulded directly in the mouth with a high-viscosity silicone before being relined with a low-viscosity silicone to ensure a better fit.

The secondary impression must take into account the anatomical changes that have occurred after surgery and certain structures that help to stabilize the prosthesis, such as the bony ridges, lingual flaps, jugal vestibule, and buccal floor, which may be partially or completely absent. On the other hand, new destabilizing factors appear, in particular scarring, alteration of the supporting tissues, which have become fragile and painful, and the presence of unsupported and mobile soft tissues.

The primary objective of this procedure is to record and optimize the utilization of the residual bearing surfaces. Initially, a polyether-type material is utilized for remargining. However, alternative materials, including polysulfides and silicones, can also be employed. Zinc oxide-eugenol is not recommended due to its hydrophilic nature, and Kerr paste is not recommended due to the risk of injury or burns.

The technique employed is predicated on a two-stage secondary impression. Initially, an impression is taken using polyether. Following reinsertion, the areas of compression—characterized by the absence of material—are identified and subsequently removed using a burr on the resin base. A second impression is then made with the same material, ensuring better registration and balanced pressure on the supporting tissues (Fig. 4).

Fig. 4. 2-step mandibular impression.

There was no evidence of lateral deviation or maxillo-mandibular imbalance. However, the determination of the vertical dimension of occlusion (DVO) must allow for labial coaptation to ensure good salivary control and its physiological and prosthetic advantages. The presence of a labial scar in the patient, however, compromises the hermetic closure of the lips, necessitating a slight reduction in the vertical dimension.

Maxillo-mandibular registrations are a compromise between the centric relation and the patient’s preferred occlusion. They must be made without manual guidance so that they can be functionally reproduced later.

It is imperative to emphasize the essential role of tongue contact with the palatal surface and anterior teeth in several functions, including phonation, bolus transport, and swallowing. Following glossectomy, the alteration of these oral cues profoundly disrupts these functions. Consequently, the re-establishment of these functions necessitates the implementation of a palatal augmentation prosthesis.

The palatal augmentation prosthesis is characterized by a modification of the palatal vault to reduce its relief and bring it closer to the tongue. The aim of this adjustment is to restore effective lingual support, which is essential for oral functions such as phonation and swallowing.

To achieve this, a functional impression is taken using a delayed-setting resin applied to the palatal surface of the upper denture. During the setting phase, the patient is asked to read a text that actively engages the tongue and precisely shapes the contact areas (Fig. 5) [7].

Fig. 5. Impression of lingual movements on the palatal part of the prosthesis.

In this particular context, the decision was made to recite a Koranic verse, namely Sura An-Nâs (Fig. 6). This selection is informed by a distinctly delineated functional objective: this Sura comprises a notable reiteration of the phonemes [s], [n], and [m], which exert a pronounced effect on the anterior and medial regions of the palate.

Fig. 6. Sura an-Nâs.

Specifically, the [s] phoneme, classified as a voiceless alveolar fricative, has been observed to elicit distinct stimulation in the anterior region of the palate, in close proximity to the incisors.

• The [n] nasal alveolar phoneme activates contact with the medial part of the tongue.

• Finally, the [m] nasal bilabial sound, although produced with the lips, often engages a particular linguopalatal posture during the transition between sounds.

The patient’s repeated actions contribute to a precise and functional remodelling of the palatal arch, thereby facilitating the adaptation of the prosthesis to the patient’s lingual movements.

The patient is required to wear the prosthesis for a period of three days, after which a follow-up appointment is scheduled to evaluate the efficacy of the false palate. If necessary, a reline can be performed to optimise lingual contact.

Once the patient is satisfied with the comfort and function of the prosthesis, the dental technician replaces the slow-setting resin with a conventional resin.

Following the fitting process, check-ups and occlusal balancing sessions are scheduled. The patient is advised to prioritise chewing on the unresected side, despite the potential risk of prosthetic destabilisation (Fig. 7).

Fig. 7. Fitting of dentures: (a) Intraoral view, and (b) Extraoral view.

Discussion

The primary objective of the surgical procedure is the complete resection of the tumour with sufficient safety margins to prevent any risk of recurrence, while preserving as much mobility as possible in the remaining part of the tongue.

Depending on the location and extent of the lesion, several types of glossectomy may be considered, ranging from partial glossectomy to total removal of the tongue [8].

In the presence of lingual substance loss, the objective of prosthetic rehabilitation is not limited to restoring masticatory function and aesthetics. The prosthesis also aims to reduce the volume of the oral cavity in order to optimise the characteristics of the resonance cavity, to direct food towards the oesophagus, and to promote better contact between the residual tongue and the palatal arch during phonation and swallowing [9].

The selection of prosthetic rehabilitation depends on the nature, dimensions and position of the lingual defect, the occurrence of an associated mandibulectomy, the presence of residual lingual mobility, and the patient’s edentulous state.

The prognosis for prosthetic rehabilitation is generally less favourable in cases of total edentulism, and the situation becomes even more complex in the presence of concomitant mandibular loss of substance, due to the lack of stability and retention of the prostheses. The utilisation of dental implants is strongly recommended to enhance stabilisation. Nevertheless, various factors—including the patient’s general health, prior surgical interventions, and financial constraints—can act as impediments to implant placement [10].

Furthermore, the risk of osteonecrosis in an irradiated area, in addition to the high implant failure rate, often contraindicates implant placement [11].

Following resection, the dorsal surface of the residual or reconstructed oral tongue should be capable of achieving some degree of contact with the palate. This is necessary to facilitate proper phonation and articulation, as well as to enable adequate swallowing by means of squeezing and collecting the bolus [12].

This contact can be achieved by various means, including:

• A reduction in the vertical dimension of occlusion, achieved by lowering the occlusal plane [13],

• Lowering the prosthetic palatal arch.

It is important to note that underestimating the vertical dimension can be detrimental from an aesthetic point of view and can lead to mycotic contamination of the labial commissures. Furthermore, lowering the palatal vault can result in the prosthesis becoming comparatively more substantial. It is imperative that prosthetic rehabilitation represents a judicious balance between the advantages and disadvantages of these approaches.

The selection of treatment depends on the specifics of the clinical situation, but the objective remains the same: to restore swallowing function, improve phonation, and thus contribute to a better quality of life and social reintegration of the patient.

It is imperative not to overlook the psychological dimension. The maxillofacial prosthesis specialist plays a pivotal role in providing comprehensive support throughout this complex process, which is marked by profound emotional changes, from the initial depression to the eventual adjustment to the new reality.

Conclusion

The palatal augmentation prosthesis represents an innovative solution for the prosthetic rehabilitation of patients who have undergone partial glossectomy. By modifying the morphology of the palatal arch, it compensates for the loss of lingual volume, optimises contact between the residual tongue and the palate, and significantly improves phonation, swallowing, and mastication.

Beyond its functional benefits, this prosthesis plays a pivotal role in restoring the patient’s self-confidence and facilitating social reintegration. Its indication must be carefully assessed, taking into account the anatomical, functional, and psychological specificities of each case, within a multidisciplinary approach that prioritises overall quality of life.