The use of an overdenture in a patient with numerous partially erupted and unerupted teeth

Clinical examination

Oral hygiene was poor with BPE scores shown in Table 3. There was a sinus present with suppuration buccal to the UR2, UR3 and UR4 region, and suppuration noted from the gingival margin of the partially erupted UL2 and LL3. No teeth were mobile or had any apical tenderness. Multiple partially erupted teeth were present, and there was a generalized hypoplastic appearance to the remaining teeth. Caries were noted clinically in the UL5 occlusal, UL6 occlusal and the LR6 occluso-buccal.

The patient had a median diastema measuring 4 mm. The UL7 and the LL7 were the only teeth with occlusal contact in the inter-cuspal position (ICP). There was an anterior open bite extending to 9 mm measured at the incisal edges.

Radiographic examination

Owing to the uncertainty about which teeth were present and the cause of the sinus in the UR2, UR3 and UR4 region, an orthopantomogram and long cone peri-apicals were taken (Figures 1 and 2). Tables 4–6 show which teeth were present.

The cause of the sinus in the upper left quadrant was still unclear, so a small-volume CBCT scan of the area was requested (Figure 3). This revealed an apical radiolucency associated with the upper left supernumerary. A full list of diagnoses is present in Table 7.

Owing to the complexities of the buried teeth and chronic infection, an interdisciplinary meeting was arranged involving an oral surgery consultant, a restorative consultant, the patient and her father. After discussing the available treatment options, the treatment plan given in Table 8 was proposed.

The patient was given time to review the treatment options with her family and opted against undergoing any invasive surgical treatment. Consequently, she expressed a desire to retain all of her unerupted and partially erupted teeth despite the associated risks of infection. As such, the sinus located in the upper left quadrant remains under review.

Initially, she decided to undertake only composite resin addition to the UR7 and LR7 as well as composite resin build-up of the UR1 and UL1 to close her midline diastema. In discussion with the patient, it was decided not to fully close the midline diastema to optimise aesthetics.

After seeing the improvement in her appearance following this treatment, the patient wished to explore the option of replacing her missing upper lateral incisors. Resin-retained cantilever bridges were provided from the upper central incisors to replace the upper lateral incisors bilaterally. Once this treatment was completed, the patient then expressed a desire to replace her missing posterior teeth with a removable appliance, despite originally objecting to this as a treatment option. A maxillary partial overdenture was made, which was well accepted. The final treatment plan provided is presented in Table 9.

The pre-, mid- and post-treatment photographs are shown in Figures 4–6.

Discussion

Pseudohypoparathyroidism, also known as Albright's hereditary osteodystrophy (AHO), is a rare metabolic disorder affecting 1:100,000 individuals.⁸ It is caused by genetic mutations affecting the GNAS gene, resulting in the resistance of kidneys and bone to the peripheral action of the parathyroid hormone (PTH).⁹ The parathyroid hormone (PTH) plays a vital role in the regulation of calcium and phosphorus homeostasis and ultimately tooth and bone mineralization.¹⁰ PHP can be subdivided into groups depending on the clinical and hormonal phenotypes.¹⁰ Dysregulation in PTH results in hypocalcaemia and hypophosphataemia, manifesting in a range of systemic and orofacial manifestations.¹¹

Systemic manifestations of PHP include short stature, frontal bossing, thick short neck and considerably reduced length of the third and fourth fingers and toes, along with dimpling of the corresponding knuckles.⁹ Oral manifestations are common and seen in more than one-third of cases with hypoparathyroid conditions.⁹ These include enamel aplasia or hypoplasia, hypodontia, delayed eruption, impaction and presence of supernumerary teeth.¹⁰

Dental management of a patient with PHP is underpinned by multidisciplinary input, which is aptly demonstrated in the case described. There are very few cases detailing the long-term management of a patient with PHP because they are usually under the care of multiple dental specialties for most of their lives. In some cases, where the patient presents with a compromised dentition, the dentist should aim to offer treatment that is minimally invasive with minimal ongoing maintenance.

The clinical considerations in the treatment planning and execution of this case can be applied to patients with other conditions presenting with similar orofacial manifestations, such as Down syndrome, Gardner's syndrome and cleidocranial dysplasia. These conditions are also typically characterized by disruption in systemic development and dental anomalies including multiple impacted or unerupted teeth, hypodontia and odontomes.¹² In addition to this, the strain and mental distress placed on these patients from a psychological perspective resulting from multiple missing teeth and compromised aesthetics is significant.

Dental professionals can be keen to find an ‘ideal’ solution – one that would solve all the problems perceived to be present. Many treatment options are available; however, there is a growing preference for implant-supported prostheses over traditional removable complete/partial dentures.¹³ The provision of implant-supported prostheses is a viable treatment option and has been shown to be successful in patients with developmental conditions, such as Down syndrome, although an increased likelihood of complications is anticipated in this cohort.¹⁴ Patients may prefer fixed replacement of teeth, but this can mean embarking on a difficult and prolonged course of treatment lasting many months or years with an uncertain outcome. In such cases, the use of an overdenture can provide a simpler approach with a more predictable outcome.

Fixed tooth replacement was a feasible option for this patient. However, there would have been challenges associated with complicated extractions under general anaesthetic, likely bone grafting and then the morbidity of the implant treatment itself. If extractions were not considered and the decision was made to use her existing dentition to achieve optimal tooth positioning, orthognathic surgery and difficult orthodontics may have been required. This would have posed a substantial treatment burden for the patient. Taking into consideration the patient's concerns, expectations for treatment, and alternative options, the patient considered this option too invasive.

A patient-focused approach to care planning has been termed patient or person-centred care. The Health Foundation reported that this approach allows professionals to work with individuals to give them the knowledge and confidence to make informed decisions about their own health.¹⁵ The ‘Involving people in their own health and care’ statutory guidance document for NHS England emphasizes the importance of focusing on what matters in the context of their lives rather than treating them as a mere list of conditions.¹⁶ This allows clinicians to empower patients by understanding what is important to them, identifying their goals and educating them on how to achieve them.

The clinical and biological aspects of dental treatments account for less than one-third of all determinants of health, and therefore, the wider context of the person is essential in improving and achieving what may be considered optimal oral health.^17,18 The authors’ concerns regarding aesthetics and the presence of chronic infection were not shared by the patient. In this case, the patient's priority was eliminating the risks associated with general anaesthesia and reducing the morbidity of treatment, accepting that this may lead to problems in the future. By giving the patient all the options, undertaking a rigorous consent process and empowering them to change their mind as the treatment progressed, a successful outcome was still achieved. This was accomplished by employing a stepwise escalation of treatment techniques culminating in the use of an overdenture, something that the patient initially had not contemplated.

In this case, an overdenture had the psychological benefit of retaining teeth and the proprioception these provide, while improving the patient's aesthetics and increasing masticatory efficiency. An overdenture would have been easier to fabricate from the outset prior to the provision of the resin-retained bridges; however, it was not until the patient's trust was gained with the initial treatment that she decided to pursue a more involved option.

When considering the prosthesis design, a metal-based denture was favoured for accuracy of fit and reduced bulk. While there was adequate interocclusal space anteriorly, the use of metal connectors in thin sections reduced the chance of fracture.¹⁹ An acrylic denture with increased thickness may not have been so well tolerated.

Conventional denture design principles were followed with appropriate bracing, reciprocation and minimal gingival coverage (Figure 6). As a result of the uncertain prognosis of the cantilever resin-retained bridges UR12 UL12, palatal backings and connectors were provided to allow possible future additions of these pontics if required.

There are many benefits to the provision of overdentures; however, they can increase the risk of caries and periodontal disease affecting the abutment teeth. Therefore, optimal oral hygiene is essential for long-term success.