Obturator Prosthesis Rehabilitation: A Series of Three Cases

Introduction

Body abnormalities or defects that compromise appearance, function and accommodation sufficient to render an individual incapable of leading a relatively normal life have usually prompted responses that seek to bring the person to a state of acceptable normalcy. The restoration of esthetics in patient with gross defects of the face and head is a valuable and often dramatic service provided by a maxillofacial prosthodontist. The replacement of missing parts such as nose, eye, ear or the construction of a device to rebuild facial or cranial contour requires utmost clinical skills and utilization of available materials.¹

A maxillary deficit typically results from surgical treatment of injuries and benign or malignant tumours. Patients with these anomalies are rehabilitated using prosthodontic techniques, with the exception of those with minor oro-antral and oro-nasal flaws, which may be treatable through surgical closure.² A channel between the nasal and oral chambers is caused by a maxillary intraoral defect as a result of surgical resection, which impairs phonetics, deglutition, and appearance. It also has psychological effects on the patient, which might cause emotional collapse.³

Both benign and malignant tumours of the maxilla and related components are capable of being removed surgically; however the procedure depends on the kind of tumour. A series of problems brought on by the removal of maxilla may have an impact on the patient's speech, appearance, mastication, and deglutition. The patient's hyper nasal speech, fluid leaks into the nasal cavity, and reduced masticator function, are all caused by post-surgical maxillary abnormalities.⁴ In order to close any congenital or acquired tissue openings of the palate and/or adjacent structures, as well as to further improve deglutition, speech, mastication, and aesthetics, the goal of prosthetic rehabilitation in such patients is to create an obturator. This significantly enhances the quality of life for such patients.⁵

For many years, maxillary deformities have been treated with prosthetic dentistry. The maxillary obturator prosthetics' history is thoroughly documented. As early as the 1500s, Ambroise Pare was the first to surgically fix a palatal deformity. The original obturators were designed to correct birth abnormalities rather than the acquired ones. Claude Martin described the use of a surgical obturator prosthesis in 1875. In 1927, Fry discussed the use of impressions prior to surgery, and Steadman described in 1956 how an acrylic resin prosthesis was made and fringed with gutta-percha to hold a skin graft inside a maxillectomy defect.⁶

The final restoration is created utilizing the Computer Aided Manufacturing (CAM) technique using the combined data. There are two fabrication methods: one involves removing material from a block (subtractive in nature), and the other involves inserting the restoration (additive in nature). In order to create 3D prototype models, stereolithography (SLA), an outgrowth of CAD/CAM technology, creates three-dimensional objects by curing liquid resin with a computer-guided laser. The ability to build personalised 3D models for each patient that are tailored to his or her demands and anatomical structures is now possible in dentistry, thanks to changes made to rapid prototyping technology that combine with laser technology.⁷

In the care of craniofacial abnormalities, stereolitho graphic models may eventually replace conventional milled models. SLA is a versatile manufacturing technique; however it should only be used in certain situations. The benefit of SLA is that models are made using light-sensitive polymers, which cuts down on manufacturing time and enables the creation of intricate anatomical structures from inexpensive materials. Unfortunately, due to the limited variety of materials used in SLA and the inability of the models to be disinfected, the polymers may result in skin sensitivity.⁸

The purpose of this paper was to report the prosthetic rehabilitation of three patients subjected to partial maxillectomy with oro-antral or oral-nasal communication as a postoperative sequelae.

Case Presentation

Case 01

A five-year-old girl child was referred by Victoria Hospital to the Department of Prosthodontics for maxillofacial rehabilitation after undergoing a cleft palate surgery. Food coming out of the patient's nose and speech slurring were the two main complaints. According to her medical history, the patient underwent cleft lip and cleft palate surgery. Intraoral examination revealed a fistula in the middle of the maxillary arch with connectivity between the oral cavity and both the nasal cavities on either side (Figure 1a). Interim obturator was designed, and the patient was informed of the available treatment options.

Procedure

Using a modified stock tray, a preliminary irreversible hydrocolloid impression of the upper arch was created. Undercuts in the defect were blocked out with cotton gauze moistened with petroleum jelly prior to taking the impression in order to improve separation from the impression. Subsequent prostheses were created taking into account the elongation of the obturator and growth of the jaw. Adams clasps were incorporated to improve prosthesis retention (Figure 1b). After the delivery of the obturator, post-operative instructions on care and cleanliness were explained. The defect's closure and clasp adaptation were periodically evaluated.

Case 02

A 52-year-old patient was admitted to PMSSY Hospital and sent to the Prosthodontics department for rehabilitation following surgery. After laboratory tests, it was noted that the patient suffered with mucormycosis in addition to COVID-19 infection. An analysis of the patient's mouth opening was done on a regular basis (Figure 2a). The impression process was postponed until sufficient mouth opening was achieved. A silicone chairside impression was created, and an obturator was proposed. The patient was instructed to report for follow-ups at regular intervals to assess how well the prosthesis was adapting. The patient was reviewed after six months for the fabrication of final prosthesis. A cast partial denture (CPD) was designed and fabricated for the patient to enhance masticatory function along with the closure of defect.

Procedure

Using a modified stock tray, a preliminary irreversible hydrocolloid impression of the upper arch was created. Undercuts in the flaw were plugged out using gauze lubricated with petroleum jelly prior to the impression procedure. The requisite oral preparation was carried out after a review of the casts. A customised maxillary tray was created for making a second impression. A medium-body addition silicone imprint was formed over the area of defect after it had been marked with additional silicone putty impression material. The tripodal obturator design was used to fabricate the metal framework, which supported, retained, braced, and established guide planes for the final prosthesis. The final cast was poured and afterwards mounted on a partially adjustable articulator to help with this process. Eventually, a Cast Partial Denture (CPD) was created utilising the direct metal laser sintering (DMLS) technology, a 3D printing method that involves melting and fusing layers of metallic powder together using a computer-controlled, high-power laser beam.

On the master cast, a pattern made of prefabricated light polymerizing plastic was used to create the framework for the final prosthesis. Plastic moulds for the I-bar cast clasp were installed and modified. The design was exposed to a light-curing schedule of 5-10 minutes in a light-curing cage following the overhead spruing of the framework. Lifted from the master cast, the framework's cured plastic design was invested with phosphate-bonded investment material. Following the completion of the burnout and casting processes, a metal framework made of the Co-Cr partial denture alloy was obtained. The metal framework was installed on the master cast and interferences were eliminated after sprue removal, rough polishing, and shaping. The casting was then corrected before being completed in a systematic manner. The metal framework was then adjusted in the patient's mouth after completion. On the faulty side, an acrylic resin record base was fastened to the framework's loops (Figure 2b).

Case 03

A woman in her late 40s came in for the treatment of her maxillary deformity. After being infected with Covid, she was diagnosed with mucormycosis. She had a 4.3x3 cm palatal deformity post her partial maxillectomy. Her remaining teeth were healthy, without any obvious caries, and showed excellent periodontal health (Figure 3a). In order to correct the maxillary deficiency, a treatment strategy was devised after discussing with the patient, and a new, definitive maxillary obturator RDP was made utilising 3D printing technology.

Procedure

The impression tray was selected based on the size of the patient's arch, and the impression was carried out using additional silicone putty impression material. During the initial impression, Vaseline-embedded gauze was inserted into the palate cavity to prevent excess impression material from extravasating into the nasal cavity. The excised region and the remaining anatomical components of the maxilla were scanned using a Cone Beam Computed Tomography (CBCT). For computer-guided surgery, Digital Imaging and Communication in Medicine (DICOM) data were imported from the CBCT scan into a sophisticated 3D treatment planning segmentation programme (Figure 3b). Following delivery, the patient was recalled every month for a period of six months to assess and modify the prosthesis.

Discussion

In each scenario, the main goal is to create a prosthesis that will fix the deformity, enhance the patient's appearance, and boost their morale in the process. The patient's mental attitude is influenced by the aesthetic and functional changes, along with physical health. If a thoroughly thought out, objective rehabilitation regimen is devised, advanced surgical and prosthetic restoration of structural and functional abnormalities in the craniomaxillofacial region can enhance the outcome of rehabilitation. The same principles that underlie face harmony, colour matching, anchorage and retention, weight bearing and leverage, durability and strength of materials employed, tissue compatibility and tolerance are essential for success in maxillofacial prosthetics as they are in prosthodontics.⁹

Obturator prostheses are frequently used in the rehabilitation of patients who have undergone total or partial maxillectomy because they aid in separating the nasal and oral cavities, restore normal speech and deglutition, and enhance the appearance of the mid-facial region by supporting soft tissues. Patients with intraoral disabilities secondary to maxillectomy typically experience swallowing problems, fluid reflux through the nasal cavity, and phonation problems. These symptoms were seen in the three cases discussed here at the beginning of treatment and became apparent after the obturating prosthesis was removed.¹⁰

In all the three instances discussed here, swallowing and fluid reflux into the nasal cavity were noted at the beginning of treatment and upon removal of the obturating prosthesis, were the common complaints reported among patients with intraoral impairment post maxillectomy. According to several authors, a properly constructed obturating prosthesis enhances speech understanding and reduces hyper nasality, which was verified immediately after the prosthesis installation in each of the three cases mentioned here^.11-13

(a) (b) Within a few days of the surgery, the impression for the delayed surgical obturator was made, resulting in the full extension of the surgical site. The obturator's proper adaptation avoids nasal regurgitation and ensures that the mucocutaneous flap is supported adequately, allowing for preservation of the surgical site during the early phases of healing. Moreover, without the inclusion of a soft liner, the obturator weighs less than the immediate surgical obturator. However, because of the difficulty in precisely reproducing the palatal contour, the speech intelligibility is subpar compared to the immediate surgical obturator. Parallel to the patient's lack of participation, there are certain inhibitions on the part of the clinician during the imprint procedure due to their fear of handling the recently healed surgical site. Due to the procedure's difficulties, the idea of a delayed surgical obturator is disregarded and avoided.¹⁴

The psychological health of a maxillofacial patient is frequently compromised during the first stage of surgery, and if the immediate obturator does not establish an acceptable seal, this will further lower their self-esteem. When a patient is in a severely self deprived state, the adaptation offered by the delayed surgical obturator could speed up the healing process and offer psychological support.¹⁵

RPD-obturator prostheses are quite effective in restoring dentulous patients with an acceptable distribution of dentition and favourable defects of the hard palate. The remaining maxillary dentition allows for the restoration of speech and swallowing as well as mastication. The challenge for clinicians is to make favourable defects that can be used to help with prosthesis retention, support, and stability in order to lessen the stress and strain placed on important abutments. This goal is best achieved when the surgeon and the maxillofacial prosthodontist work closely before the tumour resection.

Source of support

None

Conflict of interest

None