Microstomia is a term used to describe reduction in the size of oral aperture, which is either acquired or congenital.¹ The most common cause of acquired microstomia in healthy children seems to be electrical, thermal, or chemical burns. This condition may be a component of some rare genetic diseases such as Freeman–Sheldon syndrome, otocephaly, and dystrophic epidermolysis bullosa.² The most well-known rheumatic disease associated with microstomia is systemic sclerosis.³ It has been reported that the limited oral opening may result from the surgical treatment of orofacial cancers, cleft lips, trauma, burns, Plummer–Vinson syndrome, or scleroderma.⁴

Microstomic patients may experience a significant limitation in mandibular opening, eccentric mandibular movements, and an overall mandibular immobility.⁵,⁶ Several techniques have been proposed for a condition that patients find it difficult to place and remove either standard impression tray or denture itself in and from the mouth. The prosthetic rehabilitation of microstomic patients presents difficulties at all stages, from preliminary impressions to prosthetic fabrication.⁴

McCord et al.⁷ described a maxillary complete denture consisting of two pieces joined by a stainless steel rod with a diameter of 1 mm fitted behind the central incisors. Luebke⁸ described a sectional impression procedure for edentulous patients using two plastic sectional impression trays assembled with Lego building blocks and autopolymerizing resin.

Making ideal impressions is often considered the initial difficulty in treating these patients. A recommended technique to obtain preliminary impressions for microstomia is modeling a plastic impression compound, the use of stock impression trays with heavy- and light-body silicone impression materials, and flexible impression trays with silicone putty materials. In the present study, we designed a different method for mandibular and maxillary sectional denture fabrication.⁹

41 years old female with a limited mouth opening was treated in the Prosthodontics Department of Isfahan Dental School (Iran). Her chief complaint was inability to chew food due to missing teeth. Her dental history was extraction of teeth. Microstomia, in this case, seemed to have been caused by burns. Her mouth opening was measured as 25 mm. She was able to insert the mandibular denture by rotating 90°, but had a great difficulty to insert and remove the maxillary denture in spite of short fluanges of the denture. Different treatment options were discussed, and the patient agreed with our treatment plan described below.

Primary impression

Two stock trays were cut anteroposterior in two sections with a disk more than half in opposite regions as shown in Figure 1. We made the preliminary impression and then was poured with dental plaster.Figure 1

Maxillary and mandibular stock trays.

The patients with microstomia usually find it difficult to insert and remove their dentures, so it seems necessary to invent a new form of denture.¹⁰ Suzuki et al.¹¹ and Cheng et al.¹² constructed a sectional and collapsible denture for a partially edentulous patient with microstomia.¹¹ Some authors have described the method of fabricating only collapsible dentures¹³ and some have described only the sectional ones.¹⁴ Another group of authors have fabricated sectional dentures using hinge and stud attachments for this denture design. Its advantage is the use of a custom-made hinge, which is more durable and less expensive.¹⁵ In the dental literature, there are limited articles describing the method of making impressions for sectional dentures. Various snaps and keyways¹¹,¹⁴ and pins⁵ have been used for the locking mechanism of sectional impression trays. As Cheng et al.¹² stated, collapsible hinged mandibular complete denture is kept stable by tongue pressure in the lateral direction and resistance is provided by the ridge slopes. According to the authors, although the procedure is found to be time-consuming, the result is outstanding. The attachments used in this method provide more rigid attachment than magnets and there is no fear of loss of magnetic effects when using studs.¹⁵

In this clinical report, we used microcastable balls to increase retention and make it more convenient to insert and remove dentures. We also trained the patient to ensure that the dentures are inserted properly, hearing the click sound from the micro ball attachments. Another advantage is that separation in the maxillary denture, as we said in this study, did not reduce its esthetic aspect; whereas, other studies¹,²,¹⁰ may have considered esthetic criteria less acceptable. In this method, we separated the dentures in the premolar zone, which gave us more beauty as well as proper retention and stability. Ease of insertion and removal; cost-effectiveness; and provision of maximal coverage for support, retention, and stability can be regarded as the advantages of this kind of sectional denture. Increased laboratory works seem to be a limitation of this technique.

The advantages of the sectional denture described in this clinical report are as follows:

It is convenient to use due to ease of insertion and removal

Financial support and sponsorship

Nil.

Conflicts of interest

The authors of this manuscript declare that they have no conflicts of interest, real or perceived, financial or non-financial in this article.