Introduction
Microstomia, defined as an abnormally small oral orifice, can occur as a
result of trauma including facial tissues injuries, animal bites,
electrical and thermal lesions and chemical burns
(1, 2). This
condition can also arise from genetic disorders and diseases such as
Plummer-Vinson syndrome and the collagen group of diseases including
submucousal fibrosis and scleroderma (3)
or surgical treatment for orofacial cancers and reconstruction of lip
defects(4). The main problems due to
microstomia can be of functional (speech, nutrition and hygiene) or
esthetic (due to asymmetric lip placement) groups. Many treatment
options including the surgical, nonsurgical and a combination of these
two are available to cope with this abnormality. The aim of treatment is
not only providing well-functioning lips with increased mouth opening
and esthetic improvement, but also providing a stable and long-lasting
result (5). Some techniques such as
surgery and denture design modification have been recommended for
problem management associated with providing dental prostheses for
edentulous patients with microstomia(6).
Making high-quality preliminary impressions which record all anatomic
landmarks is mandatory for the successful complete denture treatment.
During the impression procedures in patients with microstomia, wide
opening of the mouth is required for the proper tray insertion and
alignment, but this is impossible (7).
Preliminary impressions from patients with microstomia have been made
using various tray modifications such as modified stock trays, flexible
trays or without conventional ones using an initial poly vinyl-siloxane
(PVS) impression. Although these techniques have been successfully
implemented, the proper method for making a preliminary impression has
not been determined. Nowadays, using computer-aided technologies make
possible to design and fabricate complete denture. Making impressions
with intraoral scanners could eliminate tray selection and adaptation,
infection transmission from patients and impressions transference to the
laboratory(8). However, several factors
such as saliva reflection and dynamic movements of soft tissues make the
digital impression from edentulous arch difficult. Making final
impression in these patients needs alternative techniques like the
sectional impression trays that has been recommended that trays should
be cut into two unequal sections so that the labial frenum is recorded
accurately in the impressions (9). The two
halves of the tray could be joined using LEGO building blocks, fins in
the handle, metal pins and burs(10).
Similarly, removable complete and partial dentures have employed the
sectional or collapsible designs to retain them in an unfolded position.
The corresponding examples include the insertion of pins, use of a
locking tool, latching a swing-lock assembly and locking the denture
segments with magnets or attachments and also using flexible denture
materials (9). It is impossible to make a
collapsible maxillary denture consisting of only 2 sections, because of
the palatal vault. Therefore, a third section is usually used for this
purpose (4).
The aim of this clinical report is to present the prosthetic treatment
applied to an edentulous patient with microstomia using an intraoral
scanner for preliminary impression and fabricating complete removable
prostheses.