Prosthodontic rehabilitation of a completely healed edentulous maxillary arch following osteomyelitis using a digital approach: Case report

Introduction

Osteomyelitis is an inflammatory condition of the bone caused by pyogenic organisms that begins as a medullary infection and extends involving the periosteum of the site. The bone becomes susceptible to disease with the introduction of a large inoculum of bacteria, trauma, ischemia, or the presence of foreign bodies. The treatment often requires surgical debridement of the bone along with antibiotics. This may require the removal of the necrotic bone, creating a defect in the intact bone.¹

This clinical report presents the rehabilitation of a completely edentulous healed maxillary arch following the removal of the necrotic bone as a result of osteomyelitis opposing the natural mandibular dentition. Patients with a single complete denture present a challenge to maintain a harmonious occlusion due to the improperly positioned, malaligned, and supra-erupted teeth in the opposing arch. Occlusal imbalance can cause tissue alterations, mucosal irritation and soreness, accelerated ridge resorption, denture instability, and ultimately patient dissatisfaction.^2,3 This case report describes the digital fabrication of a maxillary complete denture opposing natural mandibular dentition using a Han-Kuang Tan technique for occlusal equilibration.

Case Report

A patient reported the chief complaint of inability to chew food due to completely missing teeth in the upper arch. A thorough medical and dental history of the patient was taken. The patient had undergone segmental resection of the maxilla due to osteomyelitis. Intraoral examination revealed completely healed mucosa with a change in the curvature of the arch (Figure 1A). The maxillary arch was completely edentulous opposing the partially edentulous mandibular arch (Figure 1B). Extraoral examination revealed an over-closure of the lips along with the sagging of the facial muscles (Figure 4B). The patient was advised various treatment options including implant-supported prosthesis, conventional complete denture, and metal base complete denture. The patient was not willing for the implant-supported prosthesis option due to the invasive nature of the procedure. The metal base complete denture was finally opted for by the patient due to the added strength and less bulkiness of the denture.

Primary impressions of the maxillary (Figure 1C) and mandibular arch (Figure 1D) were made using the irreversible hydrocolloid material (DPI, Algitex). Primary casts (Figure 1E) were obtained and a special tray was fabricated. Border molding of the maxillary arch was done using green stick wax (DPI Pinnacle, Tracing Sticks) and the final impression (Figure 1F) was made using the light body consistency addition silicone impression material (AVUE, Gum light-body). Maxillary (Figure 2A) and mandibular master casts were obtained. The maxillary cast was then scanned (Figure 2B) and the wax pattern was digitally fabricated. The wax pattern was adapted on the cast and retention beads were placed (Figure 2C) and the casting was carried out. The cobalt-chromium denture base was finished and polished (Figure 2D). The wax pattern (Figure 2E) for the acrylic resin was made and a permanent, non-relieved, metal denture base (Figure 2F) was obtained following the conventional curing. The maxillary occlusal rim was made and the jaw relation was recorded (Figure 3A).The maxillary occlusal rim was mounted (Figure 3B) on the semi-adjustable articulator (Hanau, Wide Vue) and the teeth arrangement was done using the anatomic teeth (Figure 3D).

A thermoplastic sheet was adapted on the mandibular cast (Figure 3C) and modified cusps in the mandibular cast were marked and voids were made in the template. The sheet was then adapted in the patient’s mouth and the necessary cuspal reduction of the mandibular teeth was done. The try-in stage was carried out (Figure 3E). The final finished and polished prosthesis was obtained following curing (Figure 3F). Insertion of the complete denture (Figure 4A) opposing the clasp was retained and a removable partial mandibular denture was done (Figure 4C). The patient was kept on regular follow-up and necessary modifications were made. The patient was satisfied with the treatment.

Discussion

As a result of cyclic deformation caused by the masticatory forces, a single complete denture opposing a natural dentition tends to fracture due to flexural fatigue. The incidence of maxillary denture fracture is twice as compared to the mandibular denture due to the relatively quick crack initiation and propagation, owing to the high maximum shear stress and tensile stress.⁴ To overcome this issue, metal alloys have been conventionally incorporated in various forms in the maxillary denture base to enhance stability and reinforce the denture base. The digital fabrication of the metal denture base was done to record accurately the very fine details to further enhance the stability and retention of the prosthesis even at the defect region.

Any factor that exacerbates the deformation of the base or alters its stress distribution may predispose the polymethylmethacrylate denture to fracture.^5,6 Single complete denture opposing an unaltered dentition prevents occlusal balance during function, which compromises stability and retention; results in frequent mechanical failure of the prosthesis. This can be prevented by the occlusal equilibration of the opposing dentulous arch. Various techniques have been mentioned in the literature in which an arbitrary reduction is carried out either using preparation guides, visual inspection, or planning on the diagnostic cast.⁷ In this case report, the Han-Kuang Tan technique⁷ was used as a method for occlusal equilibration; it is a relatively simple and accurate method that involves occlusal refinement through a planned amount of odontoplasty rather than the mere arbitrary reduction of the cuspal surfaces of the teeth. The 2mm thickness of the thermoplastic sheet allowed precise reduction of the indicated tooth surfaces. This method is a quick, non-laborious, and effective method for the transfer of the modifications made in the cast to the patient’s dentition. The occlusal refinement helps to achieve a harmonious occlusion and further enhances the retention and stability of the denture.

Metal base denture provides various advantages over the conventional acrylic denture base especially when opposing the dentulous arch. The high fracture resistance and rigidity enable the prosthesis to withstand greater occlusal forces. The high strength-to-volume ratio further makes the prosthesis light in weight and also prevents the warpage of the prosthesis. Minimal tissue changes occur under the metal denture base which enhances the fit and longevity of the denture. The accurate and precise reproduction of details using the digital approach further added to the retention and stability of the prosthesis. The metal denture base provides excellent biocompatibility and thermal conductivity, thereby improving soft tissue health. The minimum thickness of the denture base further provides better adaptation and minimal interference with speech.^8,9 Although, it also has a few disadvantages like difficulty in relining or rebasing and compromised aesthetics due to the display of the metal substructure.¹⁰

A defect in the maxillary bone leads to decreased retention of the prosthesis if not properly managed. This situation is further complicated by a single complete denture opposing the natural dentition. Single complete denture requires certain modifications in the denture base as well as the opposing dentition to achieve a harmonious occlusion which further enhances the retention and the stability of the denture, and ultimately the patient’s satisfaction.

Source of support

Self

Conflict of interest

Nil