Case History
A 45-year-old woman with microstomia was referred to the Prosthodontic
Department for receiving complete denture for both maxillary and
mandibular arches in June 2018. She had scar tissues, burned face and
deformed hands caused by burning in an accident. The maximum oral
opening was approximately 20 mm in height and 35 mm in width, with tight
and inflexible labial tissues. The mandibular alveolar ridge was
resorbed moderately. After discussion and offering various treatment
options, the patient agreed to go under surgical enlargement of the oral
aperture and then fabrication of conventional complete denture. The
preliminary impression making was started after four weeks of
commissuroplasty. Petroleum jelly was used on the commissures. The
preliminary mandibular impression was made with the smallest edentulous
stock tray and irreversible hydrocolloid (Chromogel alginate, Marlic
medical industeris Co, Iran). The tray inserted by 90˚ rotation while an
intraoral mirror was used for retracting the lips as much as possible.
For the preliminary maxillary impression, stock trays with various sizes
and shapes were examined. However, inserting them was not possible due
to the limited mouth opening. Therefore, digital maxillary
impression was taken using an intraoral scanner (TRIOS 3 Basic; 3shape,
Copenhagen, Denmark). The retraction of lip and cheek and maxillary
vestibular area stretching were performed by an intraoral scanner tip in
order to successfully scan the soft tissues. The mandibular impression
was poured in type II dental stone (Dental Plaster, Pars Dandan, Iran).
The scan data were then converted to the standard tessellation language
(STL) file and transported to 3D printing device (Digi Dent Plus,
Mobtakeran mecathronic ARK Co, Iran) to print the model with resin
(Freeprint model 2.0, Detax, Germany) with 25-100 μm accuracy (Figure
1). A sectional custom maxillary tray was fabricated using the
autopolymerizing acrylic resin (Acrylic acropars, Marlic medical
industeris Co, Iran) on the printed model. Two sections of the tray were
unequal with the right section being larger, cross the midline and
extend to the left buccal frenum. Moreover, it had specified butt joint
border on the outer surface and magnet attachment. However, the smaller
tray section had specified butt joint border on the intaglio surface and
magnet attachment on the outer side to be attached to the first one. In
addition, a conventional custom mandibular tray was fabricated with the
same acrylic resin. Tray borders were trimmed in order to have 2 mm
space above the vestibular depth for the border molding.
labial and buccal vestibule, frena and postpalatal seal areas were
functionally recorded with modeling plastic impression compound (PERI
Compound; GC, Japan) (Figure 2). The final impression was made with
zinc-oxide Eugenol-free impression paste (ZOE) (Cavex outline; Cavex ,
Netherland). The impression paste was initially placed in the larger
tray segment and inserted in the mouth. Then, the other tray segment
with the impression paste placed over the magnets to ensure locking of
the 2 tray segments. After the impression material set, the tray
segments were removed from the mouth one by one and fixed together
outside (Figure 3). The mandibular tray border was molded with
thermoplastic sticks (Isofunctional, GC, Japan) and definitive
impressions were made with ZOE (Cavex outline; Cavex , Netherland).
Final impressions were boxed and poured using ADA type III dental stone
(Dental Plaster, Pars Dandan, Iran). The maxillary record base and
occlusal rims prepared in two pieces as the right and left segments
being attached to each other by magnet. They were then placed in mouth
and adjusted according to aesthetic and phonetic. The maxillomandibular
relationship was recorded in centric relation and definitive casts were
mounted on a semi-adjustable articulator (Hanau H2; Whip Mix Corp). The
semi-anatomic artificial teeth (A1,B13 Finex , Beta dent, Iran) were
arranged with bilateral balanced occlusion. Esthetic, phonetic and
occlusion were evaluated in try-in session. The important point is that
the patient could not assemble the segments because of hands deformity,
therefore integrated maxillary denture was planned for the final
prostheses (Figure 4). At the delivery appointment, denture base
extensions were evaluated, excessive pressure of the intaglio surface
was relieved and the occlusion was adjusted to derive simultaneous tooth
contact in centric and eccentric positions. The prosthesis placement was
demonstrated to the patient and delivered as well. The hygienic
recommendations were explained to the patient as well. The patient had
no difficulties using the dentures and satisfactory results were
obtained during a 5-year follow-up period. The compatibility of the
intaglio surface of the denture with the underlying tissue and occlusion
was checked, annually. Little discoloration was seen in the artificial
teeth.