Functional and aesthetic oral rehabilitation after cancer treatment using dental prosthesis and hyaluronic acid injections: A case report and review of literature

Abstract

BACKGROUND

Oral cavity cancers are highly invasive malignancies, typically treated with a combination of surgery, radiation, and chemotherapy. Surgical intervention requires the removal of all affected tissues, including the mandibular basal bone. Reconstructive procedures may involve tissue and skin grafts, such as fibula free flaps in the case of mandibulectomy. These techniques aim to minimize scarring and restore basic oral functions. However, radiation therapy may result in fibrotic scarring of the connective tissues. This case report focuses on the integration of surgical, prosthetic, and complementary therapies - including hyaluronic acid (HA) -based filler - to address both functional and aesthetic deficiencies.

CASE SUMMARY

The case involves a 70-year-old woman who underwent a right segmental mandibulectomy with fibula free flap reconstruction for pT4aN2b oral squamous cell carcinoma, followed by adjuvant radiochemotherapy. After surgery, she presented to the Odontology Department of Montpellier University Hospital with severe trismus, impaired mastication, and aesthetic concerns, including marked facial atrophy and asymmetry of the face and mouth. The multidisciplinary approach included fluoride trays to address radiotherapy-induced risks, caries treatment, a mandibular partial removable prosthesis for occlusal and soft tissue support, occlusal bonding, and HA injections to restore facial symmetry and improve soft tissue quality. HA was injected into the fibrotic connective tissue to improve skin hydration and counterbalance the asymmetry of the mouth. The combination of prosthetic rehabilitation and HA injections led to significant functional and aesthetic improvements, with a notable positive impact on the patient’s sociability and quality of life.

CONCLUSION

This case highlights how a multidisciplinary, comprehensive, personalized, and biopsychosocial approach can optimize outcomes in complex oral rehabilitation following oncological surgery.

Key Words: Dermal filler; Skin rejuvenation; Hyaluronic acid; Extracellular matrix; Oral rehabilitation; Dental prosthesis; Oral squamous cell carcinoma

Core Tip: This case highlights the full oral rehabilitation of a patient who underwent segmental mandibulectomy with fibula free flap reconstruction for advanced oral squamous cell carcinoma. A multidisciplinary approach was employed to address trismus, masticatory dysfunction, and aesthetic deficits, combining custom-made dentures, fluoride trays, and hyaluronic acid injections. Hyaluronic acid contributed to improving facial symmetry and reducing scarring, enhancing the patient’s quality of life. This case underscores the importance of innovative, patient-centered dental interventions in managing complex post-surgical complications and demonstrates a practical, reproducible approach applicable to similar clinical scenarios.

INTRODUCTION

Oral squamous cell carcinoma (OSCC) is a prevalent malignancy characterized by aggressive local invasion and significant morbidity. Cancers of the oral cavity and oropharynx represent the sixth most common cancer type worldwide[1,2]. Conventional treatments - surgery, radiotherapy, and chemotherapy - often lead to considerable functional impairments and aesthetic sequelae, including trismus, impaired mastication, fibrosis, and facial asymmetry[1,3-5]. These consequences require comprehensive management to restore oral function and improve patients’ quality of life. Mandibulectomy, for example, frequently necessitates complex reconstructive procedures using autologous tissue grafts, such as fibula free flaps, to restore basic oral function and structural integrity[6-8]. Following radiochemotherapy, segmental mandibular resection, and surgical reconstruction, dental rehabilitation is essential to restore masticatory function. This is typically achieved with fixed or removable prostheses tailored to the patient’s specific clinical condition. However, oral rehabilitation is primarily focused on dental function, often overlooking extraoral aesthetic considerations[2,8-10]. The challenges of prosthetic rehabilitation in OSCC patients highlight the need for individualized prosthetic solutions that accommodate post-surgical anatomical changes[4,8,11]. Additionally, features such as facial asymmetry, lip eversion, or lack of lip support complicate aesthetic rehabilitation, particularly since soft tissues may be the only remaining reference points for restoring the smile[12,13].

In this case report, we present a multidisciplinary rehabilitation approach following surgical reconstruction, combining removable dentures with hyaluronic acid (HA) injections to address both functional deficits and aesthetic concerns of a patient treated for OSCC. We emphasize the efficacy of this integrated treatment strategy in enhancing oral function and facial aesthetics following OSCC treatment. HA injections in facial reconstruction can augment soft tissue volume and improve cosmetic outcomes[12,14]. HA is a high-molecular-weight polysaccharide formed by the polymerization of glucuronic acid alternating with N-acetylglucosamine. It is a naturally occurring glycosaminoglycan found in the extracellular matrix of the skin, where it plays a key role in regulating cell proliferation, migration, and differentiation. It also contributes significantly to skin hydration, elasticity, and smoothness[15]. When used as an injectable, HA functions as a biocompatible dermal filler with hydrating and volumizing properties. It has garnered interest for its potential in managing radiation-induced fibrosis and in restoring facial symmetry in cancer survivors[16-18]. Clinical use of HA has been shown to improve scar elasticity, enhance facial aesthetics, and reduce the visible effects of soft tissue deficits[19-21].

To our knowledge, no prior case reports have integrated intraoral prosthetic rehabilitation with targeted perioral HA injections for aesthetic correction in post-OSCC patients. While prosthetic rehabilitation and HA fillers have each been described separately in oncology contexts[12,22], the combined use of both interventions to address commissural asymmetry and functional rehabilitation in a single multidisciplinary protocol remains undocumented. This case, therefore, offers preliminary feasibility data for a reproducible approach that integrates oral function restoration with aesthetic soft-tissue correction in the complex setting of post-oncologic reconstruction. This case report aims to explore the benefits of combining HA injections with removable partial prosthetic rehabilitation in a patient presenting with severe functional and aesthetic deficits following extensive oral cancer treatment. This approach underscores the importance of addressing not only oral function but also the psychological and social well-being of patients recovering from oncological surgery.

CASE PRESENTATION

Chief complaints

A 70-year-old female patient presented to the Odontology Department of Montpellier University Hospital with complaints of impaired oral function and noticeable facial asymmetry following treatment for OSCC. She reported limited mouth opening, difficulty with mastication, and aesthetic concerns, including collapse of the right cheek and lower lip.

History of present illness

The patient’s symptoms began three years prior, initially manifesting as recurrent infections at a tooth extraction site in the right retromolar region. A biopsy with bone sampling confirmed squamous cell carcinoma. She was referred to the ear, nose, and throat department, where a diagnosis of OSCC of the right retromolar trigone was established. Tumor invasion of the mandible necessitated a right segmental mandibulectomy, fibula free flap reconstruction, and bilateral cervical lymphadenectomy. Histopathological analysis classified the disease as pT4aN2b, according to the American Joint Committee on Cancer staging system[23], with invasion of the tongue’s extrinsic muscles and the mandible, along with metastases in multiple ipsilateral lymph nodes. The patient subsequently underwent adjuvant chemoradiotherapy with cisplatin and carboplatin-cetuximab, receiving 66 grays of radiation to the tumor site. During recovery, she developed significant trismus, severe soft tissue atrophy, and psychological distress.

History of past illness

Her medical history included hypothyroidism, managed with levothyroxine, and a prior cholecystectomy. She had no history of tobacco or alcohol use and reported no known drug allergies. She tolerated oncologic treatment well, completed chemotherapy as scheduled, and maintained adherence to her thyroid medication.

Personal and family history

The patient reported no significant personal habits detrimental to oral or general health. She used a soft-bristled toothbrush with toothpaste twice daily but did not employ other oral hygiene tools such as fluoride trays or interdental aids. There was no contributory family medical history noted.

Physical examination

Extraoral examination revealed marked facial asymmetry, with soft tissue collapse of the right cheek and loss of support in the right lower lip. Intraoral examination showed severe trismus, with a maximum mouth opening of 15 mm. Generalized gingival inflammation and poor oral hygiene were noted, along with substantial, extensive plaque accumulation, thick and scanty saliva, and a posterior mandibular edentulous space at tooth 43. Root remnants were present at teeth 16, 17, 31, 32, 41, and 42, accompanied by multiple carious lesions (Figure 1).

Figure 1 Exobuccal photos without a removable prosthesis. A-D: Exobuccal photos without a removable prosthesis, from the front (A), 3/4 profile (B), and profile (C); and endobuccal photos (D).

Laboratory examinations

No laboratory-related tests were performed in this case.

Imaging examinations

Radiographic evaluation confirmed the stability of the mandibular reconstruction with no evidence of malignant recurrence. However, due to restricted mouth opening, retroalveolar imaging was challenging. Panoramic and periapical radiographs revealed widespread carious lesions on teeth 15, 14, 13, 12, 11, 21, 22, 23, 24, 26, 33, and 37 (Figure 2).

Figure 2 Orthopantomogram (dental panoramic radiograph).

FINAL DIAGNOSIS

Dental diagnoses included extensive post-radiation carious lesions and external root resorptions, Kennedy-Applegate class II edentulism (posterior unilateral edentulism[24]), radiation-induced trismus, gingivitis, xerostomia, and soft-tissue deficits following surgical resection and facial asymmetry. These factors contributed to functional impairment and aesthetic problems.

TREATMENT

The treatment plan aimed to restore oral function and aesthetics in a patient who had undergone extensive surgical reconstruction after cancer therapy. This multidisciplinary approach addressed dental decay, occlusal dysfunction, radiation-induced complications, and facial asymmetry secondary to soft tissue and bone loss. The patient’s dental care focused on restoring function and aesthetics while treating complications resulting from oncology treatment. Initial management focused on the conservative treatment of carious lesions using minimally invasive techniques. Selective excavation was performed via a palatal approach, followed by the placement of glass ionomer restorations or biodentine, as indicated. Root remnants were preserved to reduce the risk of osteoradionecrosis, a critical consideration in irradiated tissues. Additionally, temporary direct composite restorations were placed on teeth 26 and 27 to facilitate progressive mouth-opening exercises (Figure 3A).

Figure 3 Treatment plan. A: Palatal view of dental restorations; B: Maxillary and mandibular fluoride tray.

Oral hygiene protocols were reinforced through patient education, including individualized instruction on brushing technique and the recommendation of agents to stimulate salivary flow[13,25]. A custom fluoride tray was fabricated from digital impressions to aid in the prevention of radiation-induced dental caries. A 2000 ppm fluoride gel was prescribed for lifelong use, with the patient demonstrating high compliance, requiring only minor modifications to accommodate gingival sensitivity[26,27]. Fluoride trays are presented in Figure 3B.

An optical impression was captured using the 3Shape intraoral scanner[28], and a transitional mandibular removable prosthesis with a hard base was fabricated, extending from teeth 32 to 46. This prosthesis served multiple functions: Re-establishing posterior occlusal support, enhancing masticatory efficiency, stabilizing the occlusal relationship, and contributing to neuromuscular and temporomandibular joint rehabilitation. Due to the presence of residual roots and the associated risk of osteoradionecrosis, extractions were deferred when clinically feasible[29]. The prosthesis also provided external labial support and partially compensated for jugal soft tissue loss, contributing to improved facial contour (Figure 4). To address residual facial asymmetry and volume loss, HA injections were administered, with particular attention to the right perioral and lower facial regions. The HA injections improved tissue hydration, restored structural support, and helped correct scar-associated contour deformities. This intervention significantly enhanced the patient’s facial aesthetics and psychosocial well-being, providing an important adjunct to the overall reconstructive strategy[12,14].

Figure 4 Intraoral scan, dento-mucosal removable prosthesis wear, and occlusal points for removable prostheses restoring wedging.

The procedure began with local asepsis using 2% aqueous chlorhexidine, followed by an anesthetic nerve block with 2% articaine without vasoconstrictor, targeting the branches of the right mental nerve. The operator injected the reticulated HA filler (25 mg/mL) with a 25-G cannula inserted laterally to the modiolus. The cannula entered the lower lip to recreate labial volume, first in the red lip area and then in the white lip area. The operator elevated the right labial commissure (marionette line) using 27-G sharp needle injections, delivering the material in a fan shape from a single needle entry point (the tip of the “fan”). By directing the needle upward, the operator added more volume to the mouth corners, reinforcing the supportive effect. Finally, retrograde injections along the lip vermilion restored lip shape. A total of 2 mL of HA was injected. Injection techniques are presented and illustrated in Figure 5.

Figure 5 Injection techniques. Injection techniques with a single entry point (A), perioral injection (B), lip injection (C), and an injection scheme.

OUTCOME AND FOLLOW-UP

This treatment provided a double benefit. Aesthetic Improvement: By restoring volume, HA injections rebalanced the patient's facial symmetry and reduced the appearance of surgical scars, contributing to a marked improvement in self-confidence. Functional Enhancement: By compensating for the loss of soft tissue, injections have improved the fit and comfort of prostheses, particularly when tissue healing and contraction interfered with the fit and stability of braces. The procedure was minimally invasive, well-tolerated, and performed in two sessions to optimize results. The patient, initially hesitant because she feared the result would be too artificial, was very satisfied from the very first follow-up visit. Facial pictures taken during the follow-up period are presented in Figure 6.

Figure 6 Exobuccal photos front, 3/4 profile, side; at first appointment, then after wearing removable prosthesis, then 2 weeks after injection with removable prosthesis, and 3 months after 2^nd injection with removable prosthesis worn.

This approach is in line with current literature supporting the use of HA in post-oncology rehabilitation, particularly for scar modulation, soft tissue augmentation, and aesthetic enhancement[17,18]. These injections illustrate the potential of adjunctive therapies to improve both functional recovery and psychological well-being in patients undergoing complex oral and maxillofacial rehabilitation[30,31]. Dental rehabilitation significantly improved the patient's oral function and aesthetics. The removable mandibular prosthesis successfully restored occlusal support, allowing the patient to regain masticatory efficiency, improve exobuccal aesthetics, and improve phonation. After adjustments, the prosthesis was stable and comfortable, with no major complaints reported at follow-up visits. The fluoride tray helped mitigate the risk of demineralization, despite occasional sensitivity requiring a change in the application schedule. Restorative treatments, including dental cavity management and occlusal composite bonding, stabilized the dentition and improved the occlusal relationship, thereby reducing discomfort and functional deviations.

HA injections have provided substantial aesthetic benefits by correcting facial asymmetry and increasing perioral soft tissue volume. These treatments also had a positive psychosocial impact, as the patient reported greater confidence and satisfaction with her appearance; she reported being less afraid of the looks of others in the street. Regular follow-up visits allowed for prosthesis adjustments, monitoring of dental and soft tissue health, and reinforcement of oral hygiene practices. The overall result was considered very satisfactory, meeting both the functional and aesthetic challenges posed by intensive oncological treatment (Table 1).

Table 1 Chronological interventions and oral rehabilitation.

Year	Treatment timeline
2020	Diagnosis of OSCC, surgical interruptive, reconstruction, and adjuvant radiochemotherapy
2021-2023	Follow-up visits. Radiographs confirmed stable reconstruction of the mandibular defect with no signs of malignant recurrence; the right mandibular segment demonstrated radiographic stability, and soft tissue imaging was consistent with postsurgical changes
2023	Management of trismus, caries, posterior wedging, manufacture of a removable muco-supported prosthesis, xerostomia, and gingivitis
2024	Prosthetic modifications, including denture rebasing of the removable prosthesis; HA injections were administered to treat soft tissue asymmetry and scar-related deficits, with significant aesthetic improvement

OSCC: Oral squamous cell carcinoma; HA: Hyaluronic acid.

Functional and aesthetic outcomes

Mouth-opening gradually improved during prosthetic rehabilitation, with an interincisal distance increasing from 15 mm at baseline to 22 mm after a few months. This objective interincisal distance could not be followed as mandibular incisors were lost during oral rehabilitation. The patient-reported outcomes were significant at 12 months, with the patient reporting improved symmetry and confidence. Prosthesis comfort was rated as “excellent” from the third month onward. The patient remained free of oncologic recurrence during the entire follow-up period, without dental caries reappearance, and no HA-related adverse events were reported.

DISCUSSION

This case highlights the complexity and multidisciplinary nature of oral rehabilitation in a patient previously treated for advanced cervical cancer with extensive surgery and adjuvant chemoradiotherapy. In the absence of cancer recurrence to date, rehabilitative efforts have focused on addressing the significant functional and aesthetic complications resulting from oncologic treatment. The integration of a removable mandibular prosthesis, fluoride trays, conservative caries management, occlusal bonding, and HA injections illustrates a comprehensive and individualized approach that balances clinical efficacy with patient-centered care.

Causal and temporal relationships

The clinical interventions demonstrated a clear causal relationship with the observed outcomes. The use of custom fluoride trays contributed to the prevention of radiation-induced caries, while the mandibular prosthesis successfully restored occlusal support, masticatory function, and contributed to neuromuscular and articular rehabilitation. HA injections, targeted to correct post-surgical soft tissue asymmetries and volume deficits, significantly enhanced facial aesthetics and self-image. Over time, improvements were also observed in trismus and oral hygiene compliance, supporting the logical sequencing and effectiveness of the chosen treatment modalities. Future care is planned to include a metal-based removable partial denture, continued caries surveillance, and periodic HA injections - guided by ongoing neuro-musculoskeletal rehabilitation.

Salient features and clinical innovation

This case is notable for the successful management of multiple concurrent challenges, including restricted oral access, severe trismus, high caries risk, and psychosocial consequences of oncologic treatment. Key features include: (1) The use of HA for aesthetic rehabilitation in a post-mandibulectomy context, a strategy that remains underreported in the literature; (2) The adaptation of removable prosthetic design to accommodate limited prosthetic space and compromised soft tissue support; and (3) The effective integration of preventive measures - such as fluoride trays - within a broader rehabilitative framework.

Justification of clinical relevance

This report underscores the adaptability required in dental and maxillofacial care for medically complex patients. The incorporation of aesthetic interventions, particularly HA injections, into functional rehabilitation plans illustrates the potential for innovation in improving outcomes for this population. Such interdisciplinary approaches may not only restore oral function but also contribute significantly to psychosocial recovery and patient satisfaction.

Limitations and methodological considerations

Despite encouraging outcomes, several limitations merit discussion: (1) Severe trismus necessitated multiple prosthetic adjustments and precluded the use of optimal techniques, such as the placement of composite resin under rubber dam isolation; (2) Aesthetic outcomes were assessed through patient-reported satisfaction rather than objective soft tissue measurement tools, limiting standardization and reproducibility; and (3) The current follow-up period is insufficient to assess long-term prosthetic durability and soft tissue volume stability.

Additionally, outcome variability must be considered in relation to patient adherence, systemic health status, and institutional resource availability. These factors highlight the need for future studies exploring standardized, evidence-based protocols that integrate both functional and aesthetic rehabilitation. While this single case demonstrates feasibility, its generalizability remains limited. Future research should include prospective cohorts with standardized outcome measures to validate reproducibility, long-term efficacy, and complication rates of combined prosthetic and HA-based rehabilitation in post-oncologic patients.

Recommendations and conclusions

This case supports several key recommendations for future clinical practice: (1) Early and close collaboration among oncologists, maxillofacial surgeons, and dental professionals to streamline rehabilitation timelines and outcomes; (2) Integration of HA injections as a valuable adjunct in managing facial volume loss and aesthetic imbalance following oncologic surgery; and (3) Ongoing patient education and preventive care as central components of long-term success in post-cancer oral rehabilitation.

CONCLUSION

This case report demonstrates that significant functional and aesthetic restoration is achievable in medically complex patients through a personalized, multidisciplinary approach. The strategic integration of novel aesthetic techniques into established dental rehabilitation protocols reflects a promising path forward in comprehensive post-oncologic care. It highlights the importance of an interdisciplinary approach in the dental rehabilitation of a patient with OSCC treated by segmental mandibulectomy and fibula free flap reconstruction. The use of fluoride trays, removable mandibular prostheses, caries management, occlusal surface restorations, and HA injections has shown positive outcomes in restoring both function and esthetics. Evidence supports that these interventions are essential for improving oral health, quality of life, and patient satisfaction[2,13]. Clinicians should prioritize individualized care plans that address functional, aesthetic, and psychological needs. This case provides preliminary feasibility data; future controlled studies are needed to validate efficacy and reproducibility, and future research should focus on the long-term outcomes of prosthetic rehabilitation in patients with mandibular reconstruction and the role of adjunctive therapies, such as HA, in optimizing results. This case also highlights the need for continued advancements in dental rehabilitation strategies to address the complexities of post-oncologic care, including the consideration of fibular dental implants during multidisciplinary meetings, ideally with the participation of an oral or dental surgeon.