2. Rehabilitation of a patient after a total maxillectomy with
a 2-piece magnetically retained obturator: A clinical
report.
2019
Dr. DHANANJAY SHETH
1ST MDS
DEPARTMENT OF PROSTHODONTICS AND CROWN
AND BRIDGE.
3. The goal of maxillofacial prosthetics is to restore function and esthetics to
patients with maxillofacial defects.
Any palatal defects, no matter how small, can cause difficulties in speech,
mastication, and esthetics.
If the patient has a large defect, fabricating an adequately large obturator may
not be possible because the patient is unable to insert the obturator through a
small oral opening.
If necessary, the prosthesis can be divided into 2 or more parts.
In designing a sectional prosthesis, function and the convenience of insertion
and removal of a large prosthesis needs to be considered.
The location of the contacting surfaces of the prosthesis sections should be
determined by considering ease of fabrication and insertion.
4. The defect undercut should not prevent the insertion of any section, also, the
division of the prosthesis into 2 parts should not compromise esthetics.
A maxillofacial prosthesis should have a straightforward design and be easily
manipulated by the patient.
CLINICAL REPORT
A 67-year-old man with a history of a moderately differentiated invasive
squamous cell carcinoma (SCC) of the nasal cavity involving the left maxillary
sinus and soft palate is presented.
He reported being a former smoker: 2 packs per day for 50 years (100 pack
years).
In February 2012, the patient completed 37 fractions of radiation at an outside
hospital (6700 cGy).
5. In October 2012, the patient complained of persistent drainage from the nasal
cavity, pain in the maxillary gingiva, and a foul smell, crusting, and occasional
blood from the nasal cavity. A biopsy was performed and was positive for
invasive and in situ SCC, moderately differentiated.
In November 2012, a computed tomography (CT) scan showed a 9-mm nodule
along the inferior nasal septum. The following month, the patient underwent a
total maxillectomy.
When this patient presented to the clinic in July 2014, he had difficulty with
speech and deglutition.
His remaining tuberosities consisted of soft tissue only and were incapable of
supporting his current obturator prosthesis.
The prosthesis was lacking in retention and stability
6.
7. The patient’s maxillary defect included a scar band behind his nose that, if
engaged, conflicted with the path of insertion and withdrawal. A 2-piece sectional
prosthesis was designed.
First, an impression was made with a combination of polyvinyl siloxane
impression material and irreversible hydrocolloid . The 2 parts of this impression
were made separately
The polyvinyl siloxane was placed in
the anterior undercut and, once
polymerized, was trimmed, keyed, and
replaced in position.
The irreversible hydrocolloid
impression was then made, and the 2
sections were luted together with
baseplate wax .
The impression was then poured in
Type III gypsum
8. Next, a hollow bulb obturator engaging both undercuts was processed in heat-
cured acrylic resin .
In this state, there was no path of insertion, and the patient was unable to insert
the prosthesis.
To rectify this problem, the anterior portion of the prosthesis was sectioned, and
neodymium magnets were incorporated into the acrylic resin.
To finalize the prosthesis, conventional denture methods including an occlusal
rim, interocclusal record, wax setup, evaluation for esthetics and phonetics, and
denture processing were followed.
The force between two magnet poles is proportional to the strength of each pole
and inversely proportional to the square of the distance between the
poles.”Therefore, when each obturator magnets was in the magnetic field of the
other, the prosthesis could glide easily into place.
9.
10. When a patient undergoes radical maxillary surgery, it frequently creates a
situation in which a unitary structure of a maxillary denture and obturator is too
large to be inserted orally.
In such patients, a 2-piece sectional prosthesis should be considered. Structures
within the residual maxilla and the acquired defect must be evaluated for
prosthesis retention.
Direct retention and indirect retention are of paramount importance. If the
remaining maxillary segment is edentulous, securing retention for the prosthesis
is more difficult than in a dentate patient.
The retentive capabilities of the residual maxillary segment must be evaluated
by using the same factors that contribute to the acceptable retention of a
conventional complete denture including the physical properties of adhesion,
cohesion, atmospheric pressure, and interfacial surface tension.
11. Anterior extension of the obturator provides some resistance to vertical
displacement of the anterior portion of the prosthesis.
This extension competes for insertion and removal with the extension over the
soft palate. It is therefore necessary to construct the prosthesis as 2 separate
parts and assemble them intraorally.
In this report, the anterior segment was small. The patient was given detailed
instructions on how to insert and remove the sections of the prosthesis so as not
to aspirate or swallow the small segment.
The patient placed the small segment behind his nose and then inserted the
larger segment to engage the magnets. For removal, he leaned forward and
removed the larger segment followed by the smaller one.
Once assembled, dislodgement of the anterior segment was not a concern as
there was physically no room for displacement once the larger segment was in
place.
12. Magnets have been used for the retention, maintenance, and stabilization of
maxillofacial prostheses.
A technique that included magnets between an obturator and maxillary denture
was presented in 1966 by Boucher and Heupel.
In 1970, Chalian and Barnett introduced a technique for constructing a hollow
obturator by using an autopolymerizing acryli cresin.
Robinson10 used horse shoe magnets to retain a maxillary denture and
obturator for a patient with a complete maxillectomy.
Nadeau used magnets to improve the retention of the definitive obturator and
facial prosthesis.
Magnets provide positive locking potential and, once in position, provide
consistent retentive qualities. Magnet size and diameter can be selected
according to the size of the defect and prosthesis.
13. SUMMARY
With the incorporation of neodymium magnets, the patient was able to insert and
remove the prosthesis ,which included the engagement of the anterior and
posterior undercuts without difficulty.
The ability to engage both undercuts resulted in increased retention and stability
as well as improved speech and deglutition .
This patient continued to be followed up and, at each
recall appointment, expressed his satisfaction with his
prosthesis and extreme gratitude that his chief
complaint had been addressed
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Connected by Simarian Cobalt Magnets. J Prosthet Dent 1984;52: 556-8.
5. Nadeu J. Maxillofacial prosthetics with magnetic stabilizers. J Prosthet Dent 1956;6:114-9.
6. Spinney LB. A Textbook of Physics. New York: The Macmillan Company; 1947. p. 299-315.
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J Prosthet Dent 1975;33:628-32.
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1963;13:1167-71.
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