24
Removable partial denture considerations
in maxillofacial prosthetics
NORMAN G. SCHAAF
DAVID M. CASEY
Maxillofada1 prosthetics
Intraoral ProBthcBCB DcBign ConBidcrationB
Maxillary [1ro<theses
Mand;bular prostheses
Treatment planning
Framework desian
Mandibular_flangc
prosthcsis
Jaw relation records
Summary Self-ABBcssmcnt
Aids
MAXILLOFACIAL PROSTHETICS
2. Congenital-a patient with deformed or migging
head and neck gtructures at birth. An example of
this is the patient with cleft lip and palate, or one
who has an agenesis, such as a missing or
malformed ear.
3. Traumatic-an anatomic defect in patients that
retmHB from a traumatic experience, Buch as an
automobile accident, an industrial aCCident, or a
gunshot wound.
A common prosthesis classification used in
the practice of maxillofacial prosthetic:; includes the
following:
1. Extraoral-part of the facial or cranial anat
omy (eye, ear, or nose) is missing, and a
nonliving substitute or prosthesis is used to
reconstruct the part.
2. Intraoral-refers to defects in and involving the oral
cavity, from which prostheses may be used to
reconstruct the defect area (Fig. 24-1).
Maxillofacial prosthetics is a subspecialty of
prosthodontics that deals with the prosthetic
reconstruction of patients with head and neck
anomalies. Maxillofacial prosthetics is defined as
"the branch of pro:;thodontic:; concerned with the
restoration and/or replacement of the stomatognathic system and associated facial struc
tur_s with prosthegeg that mayor may not be removed
on a regular or elective basis."I
Patients treated with maxillofacial prostheses can
be categorized as follows:
1. Surgical-a patient with missing structure in
the head and neck area that has been removed
by surgery. An example is the patient with
cancer who has had part of the maxilla removed
for a tumor of the maxillary smus.
475
476 McCracken's
prosthodontics
removable
partial
FiS- 24-1 Remit of a bilateral maxillectomy to
remove adenoid cY:5tic carcinoma. of hard palate.
3. Implant-a prosthesis may be placed within the
tissue to augment and :5upport both hard and
50ft ti55ue5.
4. Treatment-the prosthesis is used only in th_
course of a patient's treatment to support, to
splint, to stent, and/or to protect ti:5:5ue.
Although surgical reconstruction might be
the preferable method to restore lost living ti:5:5ue,
in many instances this is not possible, and th_ t1__
6f a nonliving substitute or prosthesis is needed.
Fig. 24-2 Surgeon should estimate extent of
surgical resection on preoperative cast.
nasal cavities. Without such a barrier, food and
liquids can escape into the sinus and nasal cavities,
and air leakage through SlJch a defect will result in
nasal speech. An obturator can bc placed at the
time of surgery (5urgical obturutur), during the initial
postsurgical healing period (interim obturator), or
serve as a longer-term prostheses after healing
(definitive obturator).
The primary indication for placement of a.
surgical obturator is to immediately reestab1ish the
continuity of the oral cavity (Pig. 24-2). The use of
wrought-wire clasps is indicated for adjustdbility and
to reduce the potential heavy stresses on the
INTRAORAL
PROSTHESES
DESIGN remaining teeth created by the cantilever effect of
the surgical obturator (Fig. 24-3). The use of acrylic
CONSIDERATIONS
re5in base material facilitates modification by
adjustment or by the addition of tissue-conditioning
Maxillary prostheses
material at the time of surgery. This type of
The maxillary region may need to be resected as a
prosthesis facilitates oral function immediately after
result of tumors of the gingiva, alveolar process,
surgery and can significantly reduce the hospital
palate, or adjacent :;inu:; or nasal cavities. These
stay. If the neuromuscular patterns for normal
surgical defects, as well as traumatic and cleft lip
speech are not altered, as soon as the palatal
and/ or palate defects, may require treatment with
structure is restored with a prosthesis, the patient
maxillofacial prostheses.
may regain speech within a normal
range.
Obturators
After 7 to 10 days, the prosthesis and surgical
Obturators are prostheses that are used to close
pack are removed, and the surgical prosthesis is
maxillary defects and to reestablish a barrier
between the oral cavity and the sinus and/or
Chapter
24
Removable
prosthetics
partial
f1ig. 2':1:.j Teeth removed in _urgicai area and
WClJ\-UP of 0urt;ica1 obturator iB prepared,
Wrought-wire clasps retain pro_the_i__
reproce;o;;o;ed with new acrylic re5in. The
pro5thesis now bQcomQs thQ interim prosthesis,
which serves throughout a 4- to 6-month healing
period. These prostheses require periodic modification with tissue conditioners as healing
progre1j1je1j, Multiple wrought-wire clU5p5 remain
the retainer5 of choice during this intcrim period_
Prosthetic teeth may be added Lo enhance
esthetics, however, mastication on the surgical
side should be avoided because of the lack of
tissue support. Innovative frame de1jign1j are often
nece;o;;o;ary for the definitive obturator for patients
who havc some remaining dentition (FiF;, 24-4),
Aramanl,3 developed a classification for partially
edentulous maxillectomy dental arehe;o; (Fig. 245), and Parr4 proposed innovative frame designs
for variou;o; ;o;urgical defects. In the classic
midline maxillectomy, the structures that normally
support a prosthesis are logt on the surgical side
(see Fig. 24-4). The frame design and arrangement
of clasps is critical to the retention of a maxillary
removable partial denture obturator.5,6 In every
case the prosthesis should have occlusal rests for
support, guide planes, clasps that engage
significant retentive areas, and reciprocal tooth
contact for stabilization. Attention must also be
directed toward the
denture
considerations
in
maxillofacial
477
surgical area to gain additional retention if
possible, especially if few teeth remain. Brown7
reported how the vertical height of the lateral portion
of the obturator above the buccal scar band can
help prevent vertical displacement (Fig. 24-4, B).
Speech aids are prostheses that are functionally
shaped to the palatopharyngeal musculature to
restore or compensate for areas of the soft palate
that are deficient because of surgery or congenital
anomaly (Fig 24-6)- Such a prosthesis consists of
the following three parts: (1) the palatal part, which
provides stability and anchorage for retention; (2)
the palatal extension, which crOB5eB the rcBidual
Boft palate; and (3) the pharyngeal part, which fills
the palatopharyngeal port durins mu_cular f1-\fiCtion (PiS' 24-7).
A pediatric gpeech aid is a temporary prosthesis
used to improve voice quality during the growmg
years. It is made of materials that are easily
modified a growth or orthodontic treatment
progrcBBcB. Because a speech aid has a signifi
cant posterior extension into the pharyngeal region,
torque is evident from the long moment arm- A basic
principle of posterior retention with anterior indirect
retention must be applied to the de5ign of _mch a
maxillary prosthesis. Posterior retention is gained by
the use of wrought-wire clasps around the most
distal maxillary molars
(Fig 24-R), whereas the anterior extension of the
prosthesis onto the hard palate provides the indirect
retention. If there is inadequate clinical crown length
and undercut to provide retention,
orthodontic bands with buccal tie-wings can be used in
conjunction with the wrought-wires.
This design facilitates the maintenance of the
pharyngetll pelft of the pediatric speech aid in the
proper position in the palatopharyngeal openIng.
In the adult whose palatopharyngeal insufficiency is a result of a cleft palate or palatal
:>urgery, an adult :5peech aid prosthesis can be
constructed of more definitive materials because
growth changes will not have to be accommodated.
If teeth are missing, the speech aid will incorporate
a retentive partial denture framework. The basic
design should include poste
rior retention and anterior indirect retention (Fig. 249).
47
8
McCracken's
prosthodontics
removable
partial
A
Vertical
displacement \
Le33
B
jJ
Greater
Given horizontal
flexure
c
D
......
Fig. 24-4 A, Coronal view of proposed maxillary resection. Bold lines designate typical area
to be resected. B, Geometric illustration demonstrates value of lateral wall height in design
of removable partial denture obturator. As defect side of prosthesis is displaced, lateral wall
of obturator will engage scar band and aid in retaining the prosthesis. C/ Coronal section
with surgical obturator in place. With prosthesis in place, relation of scar band (arrow) to
lateral portion of the obturator can be seen. Buccal scar band will develop at height of
previous vestibule where buccal mucosa and skin graft in surgical defect join. D, Axial view
of resected area illustrates defect. Dotted lines indicate areas available for intraoral
retention.
Chapter
24
Removable
partial
denture
considerations
in
maxillofacial
479
prosthetics
IV
II
III
V
VI
Fig;. 24-5 Ammemy'B2 claBBification for partially edentulow: maxillecromy dental arches:
Class I-Midline reBection. ClaM II-Unilo.tcro.l resection. Class Ill-Central resection. ClaBB
IV-Bilateml antcrior_posterior resection. Class V-Posterior resection. Class VIAnterior
reaedion.
3
2
Fig. 24-6 Oral-pharyngeal view of pediatric patient
with residual palatopharyngeal insufficiency and
therefore hypernasal speech.
Fig. 24-7 Complete three-part pediatric speech aid:
(1) palatal part, (2) palatal extension, and (3)
functionally shaped pharyngeal part.
48
0
McCracken's
prosthodontics
removable
partial
A
Fig.24-8 Retention for pediatric speech aid is
gained with specially designed wrought-wire
clasps designed to engage buccal tie-wings on
orthodontic bands around the most posterior
maxillary molars.
R
Fig.24-10 A, Palatal lift pro:sthe:si:s mu:st be
designed with po:!terior retention and anterior
indirect retention to counteract weight of soft palate.
H, Palatal lift prosthesis lifts flaccid palate
posteriorly
and
superlorly
to
narrow
palatopharyngeal opening and im
prove voice quality.
Fig. 24-9 Principle of posterior retention-anb_rior
indimct n!hmtion applieg in function.
Palatal lifts
Palatal lifts are prostheses that lift the flaccid soft
palate posteriorly and superiorly to narrow the
palatopharyngeal opening (Fig. 24-10). Patients
with normal, intact anatomy, but with hypernasality
and nasal emission of air, have the condition
referred to as palatopharyngeal incompe
tency. This condition results from a paralysis of the
activating muscles and soft tissues. A palatal lift
prosthesis needs definitive posterior retention and
anterior indirect retention to resist displacement by
the weight of the soft palate. This prosthesis i5
helpful in lreatj.n15 patient:; with flaccid paralysis of
the soft palate that results from head injuries,
cerebral palsy, muscular dystrophy, or myasthenia
gravis. Success with a palatal lift prosthesis
depends upon the presence of a number of
maxillary posterior teeth that can provide retention
for the prosthesis, and, equally important, a flaccid
soft palate.
Chapter
24
Removable
prosthetics
partial
A
B
Fig. 24-11 A, Patient with partial glossectomy cannot reach palate for appropriate speech and swallowing. B, Palatal augmentation of maxillary prostheses functionally shaped to permit palatoglossal
functions.
Palatal augmentations
Some patients may have lost some part of the
tongue aiS a result of cancer surgery With less
tongui:' _tructurl::!, thl::! ability of the tongue to
reach the palate for normal speech and ;swallow
ing is compromised (Pig- 24-11). In the!::e in_hmces the contour of the palate can be auomontod. by a prosthesis to fill the "'pace of Dondc:r
so that a food bolus can be lll.Ore ea::>ily 111oved
posteriorly into the oropharynx. Such a removable
partial denture prosthesis, when it is modified,
would provide a functionally shaped acrylic resin
palatal portion that establishes the boundaries of
augmentation appropriate for speech and
swallowing.
After
healing
and
patient
accommodation, a definitive prosthesis constructed
with a cast metal frame can be fabricated.
denture
considerations
in
maxillofacial
481
Mandibular prostheses
The patient who has lost part of the mandible suffers
one of the most debilitating of all stomatognathic
insults. When this loss is combined with a partial
glossectomy,
and/or
partial
pharyngectomy,
oropharyngeal function may never again be
acceptable. Although partial mandibu
lar loss is occasionally seen secondary to trauma,
congenital defects, or osteoradionecrosis, the most
common cause is surgical removal of a malignant
neoplasm. The tumor may have begun within the
mandible, but it is more common for the tumors to
be in close or direct apposition to the mandible
(such as the tonsillar fossae or posterior-lateral
tongue), requiring partial resection to obtain clear
surgical margins.
Partial mandibular resections fall into two main
categories: marginal resections and segmental
resections, as classified by Cantor and Curtis (Fig.
24-12).8 The marginal resection (Type I) preserves
the inferior border of the mandible and its continuity,
thereby sustaining the potential for normal function.
This is by far the least debilitating of the two types
of partial mandibulectomy. In marginal resections of
mandibles with some remaining teeth, only the
denture-bearing surface of the residual mandible in
the area of
surgery is compromised. With good remaining dental
support, near-normal function can often
be achieved with prosthodontic rehabilitation.
When a complete segment of mandible from
the alveolar crest through the inferior border is
removed (segmental resection), discontinuity results
and function of the remaining mandibular segment
is severely compromised. For prosthodontic
rehabilitation to be po;s;sible, it i5 imperative that
the functional movements of the remaining residual
mandible are under::>tood.9 Restoration of the
mbiSing segment may be accomplished at the time
of primary surgery or as a delayed procedure.
However, virtually all anterior defects (Type V) are
reconstructed at the time of surgery. Unfortunately,
the reality associated with head and neck surgery is
that many lateral segmental mandibulectomies are
not surgically reconstructed. The reasons for this
include low cure rate for advanced tumors, high
recurrence rates, philosophy and training of
the surgeon, and other possible complications.
Many head and neck cancer patients receive
48
2
McCracken's
prosthodontics
removable
partial
I_t
___"_
[J 0
\"
,,r
,
/'
IV
v
FiS' 24-12 Clmtor and Cmti;:; cltl:>:>ification of
partial mandibulcctomy. (Redrawn from Cantor R,
Curtis TA: J Prosfhet Dilnt 25:446-457, 1971).
adjunctive radiation therapy, putting them at
increased risk for failure of reconstructive grafts,
although hyperbaric oxygen treatment can improve
success rates of these grafts.lU Endosseous
implants placed in the remaining segment of
mandible may be a treatment altl"rnative to servl"
as support or retention aids for prostheses. This
chapter, however, will focus on conventional
removable partial denture rehabilitation, and the
interested reader iB referred to an additional
:source to learn about this treatment
option.9
The determinants of normal mandibular
movements are the two temporomandibular joints,
the neuromuscular complex, and the dentition.
When considering the partial mandibulectomy
patient, one has to realize that 50% of the
determinants may no longer be functioning
normally, as illustrated by several jaw movement
studies of mandibular resected patients.ll-13
Fig. 24-13 Stability of mandibular prosthesis increases as cro!'i!'i-afch tripod effect approaches
equilat
eral triangle. Least stable situation is where
remaining teeth lie in single line.
Treatment planning
Before surgery, consultation between the prosthodontist and the head and nl"ck "mgeon is
paramount for improving the postsurgica 1 pros
thodontic result1 Th{l value of any remaining teeth
in a discontinuity defect cannot be overemphasized.
Even though thl"ir pl"riodontal and restorative
Btatus may be Ie;:;;:; than de8irable and the
possibility of achieving ideal restorative treatment
on the remaining and tissue may be further
compromised, these teeth may be able to provide
support, stability, and retention that will improve the
prognosis of the prosthesis. The greater the crossarch tripod effect that can be developed from the
remaining teeth, the greater
the stability of the prosthesis and the more
favorable the prognosis (Fig. 24-13). Even when
only unsound teeth remain, a transitional man
dibular resection prosthesis with wrought-wire
clasps and an acrylic resin major connector may be
used through the post-surgical stage. The
Chapter
24
Removable
prosthetics
partial
denture
considerations
in
maxillofacial
483
A
B
_
D
E
PiB- 24-14 A, Roontsonosr;;u:n of lateral mar8mal
mandibulectomy. 8, Intraoral view. C Intaglio view of
prosthesis. D, Occlusal view of prosthesis. K
Prosthesis in place.
value of sound remainins ieeih in a heaHhy status
caf\1\ot b_ ov_r_mphasized.
Emphasis on home care is esgenHal. Because
poor oral hY15iene habits are difficult to reverse, a
history of poor oral hygiene is a significant factor
to be considered in treatment planning
postsurgical prostheses.
Framework design
All framework designs must incorporate basic
prosthodontic principles of design, with modifications determined on an individual basis. A
discussion of framework design for the resected
mandible will be complex because of the infinite
variations of remaining teeth and types of
resections. However, in discussing design prin
ciples, the Canier and Curiis8 classificahon of
resected mandibles in edentulous situations is
expanded to describe the Kennedy Class I and
Class II partially edentulou3 arche3.
Type I l'egection
In a Type I resection of the mandible, the inferior
border is intact and normal movements can be
expected to occur. The major compromise will be in
the quality of the edentulous denture-bearing area.
Ideally one would like to see a firm, nonmovable
tissue bed with normal buccal and lingual vestibular
extension.IS If the defect is lateral, the framework
would be typical of a Kef\1\edy Class II design,
taking into account whatever modification spaces
may be present (Fig. 24-14). When the
48
4
McCracken's
prosthodontics
removable
partial
A
B
c
D
fig. 2t.l-15 A, Roentgenogram of anterior m::Jrgin::Jl mandibuli'ctomy, with two remaining
molars. fi, Intraoral view. C framework design. D, Intraoral view of pro;:thp<:i<: in pl;:}ce;
functional with no necessary modification after 10 years.
marginal resection is in the anterior areal the
de:;ign may be more typicCll of Cl Kennedy Cld__
IV design (Fig. 24-15).
Anterior marGinal reJectionJ JomdimeJ include
part of the anterior tongue and floor of the mouth.
With the loss of the normal tongue function, the
remaining teeth Clre no longer retained in a neutml
Lane, ClIld a:; a re_ult they often collelpJe lin_ually
(Fig. 24-16). If pClrt of the anterior tongue is
resected, and the arch is not re5tored within a
relatively :short time, this lingual collapse caused
by the labial musculature may necessitate the use
of a labial plate design.1o These authors believe
that corrected cast impression procedures should
be used in the fabricatiOn of all removable partial
dentures in partial mandibulectomy patients. The
importance of functional contours of the denture
base
in the surgical site cannot be overemphasized.
Capture of buccal, lingual, and labial functional
contours in the final prosthesis can contribute
significantly to stabilization of the prosthesis,
especially in discontinuity defects.17,1
Type II fe_e('tion
In the Type II resection (lateral continuity defect),
the mandible is often resected in the re!?;ion of the
second premolar and first molar. Resection should
be through the alveolus of an extracted tooth rather
than through an interdental region. This preserves
adjacent bone to the remaining tooth and allows its
use as a removable partial denture abutment (Fig.
24-17). If
there are no other missing teeth in the arch, a
prosthesis is usually not indicated. There are
situations, however, where a prosthesis may need
to be fabricated to support the buccal tissues, and
to help fill the space between the tongue and cheek
to prevent food and saliva from collecting in the
region. Framework design should be similar to a
Kennedy Class II design, with extension into the
vestibular areas of the resection. This area would
be considered nonfunctional (Fig. 24-18) and
should not be required to support mastication.19 It
must be remembered that extension into the defect
area can place significant stress on the remaining
Chapter
24
Removable
prosthetics
partial
denture
considerations
in
maxillofacial 485
A
B
c
D
rig. 2'1:-16 A, Cast of collapsed dental arch :5 yearli after extraction of mandibular inciliorli;
anterior mar8inal mandibuledomYi excision of anterior floor of mouth and partial anterior
glossedomy. Note severe tilting of all teeth, and contad of canine crowns. B. After seledive
extractions. labial bar major connector design. C, finished prosthesis. D, Intraoral view,
prosthesis in place, functional with no modifications necessary aftcr 9 ycars.
abutment teeth; therefore occlusal rests should be
placed near the defect, alons with an attempt to
gain tripod support from remaining teeth and
tissues where possible.
The following are three common patterns of
tooth lo!;:!;: !;:ggn in Typg II rg!;:gction!;:: mi!;:!;:ins
molars on the intact side of the arch (Fig. 24-15, B);
missing all of the posterior teeth on the wrgical _idg
of thg arch, and _omg or all of thg anterior teeth
(Fig. 24-18, C); and mi""ing molar teeth on the
nonsurgical side, along with all of the anterior and
posterior teeth on the surgical side of the arch (Fig.
24-18, D).
An example of a framework design for a Type II
mandibular resection with missing molars on the
nonsurgical side is illustrated in Fig. 24-18, B. The
choice of major connector depends on the height of
the floor of the mouth as it relates to the position of
the attached
Fig. 24-17 Section through dentulous region of
mandible should be through center of socket of
extracted tooth, rather than interdentally. Adequate
bone remains for support of tooth adjacent to defect.
48
6
McCracken's
prosthodontics
removable
partial
B
A
c
D
FiS' 24-18 A, PramQ dQgign for TypQ 11 regection, no teeth mi__ing on the nonresected
side. NotQ provigion for exten>:ion into resection space between tOngue and cheek. fi,
Type II design, with mi1>1>ing po::;terior teeth on nonreBected Bide. C, Type II deBi/5fl,
with missino anterior teeth. V, Type II design, with missing anterior and posterior teeth.
gingival margin:> dming function. A distal
exten1iion bCl;je with artificial teeth is often used on
the surgical side if space is available. The extent of
this base is determined by 11 functional impression
made to develop a corrected cast. Retention can be
achieved through the use of various types of clasp
assemblies on the distal abutments. Indirect
retention can be derived from rests prepared in the
mesial fossae of the first premolars and/ or the
lingual surfaces of
the canines. Use of o.n infrabulge retainer on the
surgical side is often not possible due to the shallow
vestibule that results from surgical closure. Location
of minor connectors should be physiologically
determined to minimize the stress on the abutment
teeth and to enhance resistance to reasonable
dislodging forces. Wrought-wire circumferential
retainers are acceptable alternatives.
In a Type II mandibular resection, where
Chapter
24
Removable
prosthetics
partial
denture
considerations
in
maxillofacial
487
A
Fig. 24-20 Conventional clasping by use of alternating buccal and lingual retention (urruw_).
R
Fig- 211-19 Example of Swing-Lock major
nmnectm dQgi5n- A, Maximal rehmtion i_ achi_v_d
on abutment \1nd"rC\1h, that would be
inacce__ible willi conventional clagp d,,_ign- B,
SW'ing-Lock in open position
pm:terior and anterior teeth are missirlg on the
dgfgct gide, the l'emainif\g t__th on the intact gidg
of the arch are often pl'_g_nt in a gtraight 11M
configul'ation- An I"xampll" of a de_ign for this
situation is illustrated in Fig. 24-18, C. Embrasure
clasps may be used on the posterior teeth, with an
infrabulge retainer on the anterior abutment. In
some situations, a rotational path design may be
used to engage the natural undercuts on the mesial
proximal surfaces of the anterior abutmenbs.
LingutlJ retention with buccal reciprocation on the
remaining posterior teeth should also be
considered. The longitudinal axis of rotation in this
design should be considered to be a straight line
through the remaining teeth- Depression of the
prosthesis on the edentulous side will have less of
a chance to
dislodge the prosthesis if retention is on the lingual
surfaces than if on the buccal. Physiologic rdief of
minor connector5 is tllwaY5
recommended. Where the remaining teeth are in a
straight line, a Swing-Lock major connector design
may be used to take advantage of as many buccal
and! or labial undercuts as possible (Fig. 24-19).
BeCtlU5e elderly patients often complain of difficulty
manipulating Swing-Lock mQchanisms, in straightline situations it may be possible to U"I" alternate
buccal and lingual retention effectively (Fig. 24-20).
Tn the Type TT resection with anterior and
posterior missing teeth on the resected side and
posterior missing teeth on the nonresected side, the
prosthesis will have three denture base regions (Fig.
24-18, D). This prosthesis may have a straight-line
longitudinal axis of rotation as previously discussed.
H.ests should be placed on as many teeth as
possible, minor connectors should be placed to
enhance stability, and wrought-wire retainer9 :;tre
:;tn :;tccept:;tbIQ :;tltQrnative to the bar clasps.
Type III resection
A Type III resection (see Fig. 24-12) produces a
defect to the midline or further toward the intact side,
leaving half or less of the mandible
48
8
McCracken's
prosthodontics
removable
partial
remaining. The importance of retaining as many
teeth as possible in this situation cannot be
overemphasized. The design of a framework for
this situation would be similar to the Type II
resection shown in Fig. 24-18, C and D. The
longitudinal axis of rotation is again considered to
be a straight line through the remaining teeth. In
this resection there is a greater chance of
prosthesis dislodgement caused by a lack of
support under the anterior extension. Alternating
buccal and lingual retention in a rigid d!:,gign, or
th!:' Swing-Lock d_gign ghould b_ considered.
Type IV resection
A Type IV resection (see Fig. 24-12) would use the
same design concepts as the Type II or III
resections with the corresponding edentulous
areas. If it Type IV re$ection extend$ to the midline
with the extension of a graft into the defect area,
but does not include temporomandibular joint
reconstruction on the surgical side, the design
would be simi[ar to the Type III resection with an
extension base on the surgical side.
lf the lype IV resection extends beyond the
mldlin_, with l_gg than half of th_ mandibl_
r_majning, th_ d_sign will b_ similar to th_ Typ_ II
resection that has an extension base into the
surgical defect area
Typl2
V
PI2Bl2ction
In the Type V resected mQ.ndiblc, when the
anterior or posterior denture-bearing area of the
mandible hCl;J been ;JurgicCllly recon;Jtructed,
the removable partial denture de:>ign i:> :>imilar to
the Type I re:>ection de:>ign (:>ee Fig. 24-14). The
principle difference bet'ween a Type V rQsQctQd
mandiblQ and thQ intact mandiblQ ""ith
the Bame tooth 1055 pattern i5 in the manaGe
ment of the soft tissue at the graft site. For design
purposes, one should consider the residual
mandibles of the Type I and V resections to be
similar to nonsurgical mandibles with the same
tooth loss pattern.
Mandibular flange prosthesis
The mandibular flange prosthesis, as described by
Robinson and Rubright}° is used primarily as an
interim training device. When no missing
teeth are supplied, it may be considered as an
appliance rather than a prosthesis. This appliance is
used in dentulous patients with nonreconstructed
lateral discontinuity defects who have severe
deviation of the mandible toward the surgical side
and who are unable to achieve unassisted
intercuspation on the nonsurgical side (Fig. 24-21).
Generally these patients have had a significant
amount of soft tissue removed along with the
resected mandibular segment, and have had
surgical closure by suturing the lat_ral surfac_ of th_
tongu_ to th_ buccal mucosa. Scarring will have
occurred during healing, particularly if the patient
has not been placed on an exercise program during
the healing period. If, after a period of intensiv_
orophysioth_rapy, the patient still cannot achieve
unassisted occlusal contacts, a flange prosthe$is
can be considered. The flange prosthesis is
designed to restrict the patient to vertical opening
and closing movements into maximum occlusal
contacts. Over a period of timc, this guided function
should promote scar relaxation, allowing the patient
to make unassisted masticatory contact.
The components of the flange prosthesis include
the major and minor connector" needed to support
stabilize, and retain the prosthesis, the buccal guide
bar, and the guide flange (Fig. 24-22). The buccal
guide bar is placed as close as possible to the
buccal occlusal line angle of the relTlainin15 natural
teeth to allow maximal opening. The lateral position
of the bar must be
Fig. 24-21 Dentist assistance is required to manipulate
mandible to achieve occlusal contact position in
patient with right partial mandibulectomy.
Chapter
24
Removable partial
prosthetics
adequate to prevent the guide from contacting the
buccal mucosa of the maxillary alveolus. The length
of the bar should overlie the premolars and first
molar where possible. Retention of the maxillary
frame should flot be problematic because the force
directed on the bar is in a palatal direction. The
guide flange is attached to the mandibular major
connector by two generous interproximal minor
connectors. As with the maxillary framer significant
interproximal tooth Wudure mu_t be cleared to
provide the necessary bulk for the minor
connectors The height of the guide flange is
determined by the depth of the buccal vestibule. A
small hook is placed on the medial of the top of the
guide to prevent disengagement on wide opening.
Because the mandibular segment has a constant
medial forcer the flange acts as a puwerfullever
with a
denture
considerations
in
maxillofacial
489
strong lateral force on the teeth. Therefore extra
rests and additional stabilization and retention on
multiple teeth must be considered to avoid
overstressing individual teeth. Retention on the tooth
adjacent to the defect is critical for resistance to the
liftin)'; of the frame. Lingual retention in the premolar
area may be considered as an aid in resistance to
displacement.
When necessarYr missing teeth can be added to a
flange prosthesis. Flange prostheses can be
provisionally designed for modification into definitive
removable partial dentures after guidance is no
longer necessary. This is accomplished by removal
of the buccal flange and buccal guide bar
components after the patient is able to make
occlusal contacts without the use of the gUlde.
However, many patients with mandibular resections
have difficulty making repeated
A
B
c
D
Fig.24-22 A, Buccal guide bar (arrow) on maxillary framework positioned to allow maximum
opening and to prevent guide flange from contacting buccal mucosa of maxillary alveolus.
B, Buccal flange (arrow) on mandibular framework C and D, Buccal flange on mandibular
segment into occlusal contact position.
49
0
McCracken's
prosthodontics
removable
partial
occlusal contacts, a fact described in several
studies.ll-l3 Occlusal considerations in mandibulectomy patients have been discussed extensively by Desjardins?l
Palatal occlusal ramps have been used to guide
those patients vvith less severe deviation than
those who require a guide flange into a more Btable
intercuspal contact position. These prostheses
incorporate a palatal ramp that simulates the
function of the flange prosthesis (Pig. 24-23).22
This inclination of the palatal ramp is determined by
the severity of the deviation of the remaining
mandible.23 Some patients have the ability to move
laterally into occlusion but have a tendency to close
medially and palatally rather than close into an
acceptable cuspal relationship. These patients can
benefit from a palatal ramp, which can be::>
function-'\lly ge::>nerated in WaX at the try-in
:stage. Thi:s give:s a platform for occlu:5al contact
in the entire buccal-lingual range of movement. A
:5upplemental row of prosthetic teeth may be
arranged, then removed at the boil-oat :5tage, and
processed in pink acrylic resin for esthetim.
Patients who have experienced both :5mooth and
toothform ramps usually prefer the tooth form if the
width i:5 adequate (rig. 24-23, B).
Jaw relation records
Interocclusal records must be made using verbal
guidance only for resection patients with discontinuity defects. A hands-on approach, like that used
for conventional edentulous jaw relation records, will
lead to unnatural rotation of the mandible and an
inaccurate record. The patient Bhould be inBtructed
to move the mandible toward the nonsurgical side
and dose into a nonresistant recording medium at
the preestablished occlusal vertical dimension,
which will be the occlusal contact position. If the
surgical side is significantly deficient, an occlusion
rim may have to be extended into the defect area to
support the recording medium. Head position is of
extreme importance during registration of jaw
relation records (Fig. 24-24).z'I If the patient is in a
semirecumbent position in the dental chair during
the recording procedure, the mandible may be
retracted Clnd deviated toward the ::>urgical ::>ide,
preventing movement toward the intact side. To
minimize this problem, the recording :5hould be
made with the patient Beated in a normal upright
postural poBition.
Mmt patients with unrecomstructed lateral
discontinuity defects can make lateral movement::>
toward the non:surgical _ide, even
A
R
Fig. 24-23 A, Palatal ramp generated in wax at try-in. Inclination of ramp used to guide
mandible to intercuspal occlusal position. B, Processed palatal ramp on maxillary
removable partial denture. It provides enlarged occlusal table to facilitate occlusal contact.
Chapter
24
Removable
prosthetics
partial
denture
considerations
in
maxillofacial
491
without the presence of a lateral pterygoid muscle
functioning on the balancing (surgical) side. This is
due to the compensatory effects of the horizontal
fibers of the temporalis muscle and the lateral
pterygoid muscle on the normal side, causing a
rotational effect on the remaining condyle.25
A
SUMMARY
Maxillofacial prosthetic treatment of the patient with
an oral defect is dIllung the most chdllengins in
dentiBtry. Defects arc highly individual and require
the clinician to call upon dll knowledge and
experience to fabricate a functional pro_the_i_. The
basic principles and concepts described throughout
this text will help to successfully design maxillofacial
removable Pdfhal dentureB.
Mandibular resection prostheses are among the
most challenging in all of prosthodontici'o:- A basic
understanding of the functional movement of the
resected mandible is essential for those performing
this prosthetic procedure. Removable partial
prostheses for the marginally resected mdndible for
the most part require conventional designs, with
emphasis on functionally registering the borders of
the resected cued. The segmentally resected'
mandible prcsents different problems, requiring
nonconvenhonal proBthodontic BolutionB. Some of
these problems and solutions have been discussed
in this chapter. It is hoped that the information given
in this chapter will stimulate the interested reader to
further his or her knowledge by a study of the
illdxillofacial prosthetic literature.
R
r.
I)
fig. ZI}-ZI} Effect of postUral position on movement
in left partial mandibulectomy patient. A,
Mandibular position at rest in upright position. H,
Mandibular position at rest in dental chair tilted 45
degrees from horizontal. C Maximum excursion
toward normal Qid" in upright pm:ition D,
M:_:,,:imum ,:>xcun:ion toward normal side i1'\
de1'\bl ch"ir "t 45-dogroo tilt.
49
2
McCracken's
prosthodontics
removable
partial
SELF-ASSESSMENT
AIDS
1. In planning the surgical and restorative
treatment for a patient with malignant oral
disease, the dentist should see the patient
before surgery to coordinate definitive care. To
solicit the surgeon's cooperation in this regard,
what rationale would you give for seeing the
patient at this time?
2. What is the primary purpose for placement
of a surgical obturator7
3. Speech aidll and palatal liftll often require
significant posterior extension into the pharyngeal region This requires the clinician to use
what basic principles of design?
4. Other than natural teeth, what structures
associated with the resultant defect from
m>\yilll;\ctomy can bl;\ usl;\d to ausment prosthl;\Hc stability and retention?
5. How do natural tooth crown contour and palatal
confisuration influence the retention and stability
of a maxillary obturator prostheSiS?
6. Clinicall11cthod" u"cd to '5tabilize the rc::!idual
mandible after surgery that results in
diocontinuity depend on at leaot three criteria.
Identify the"e and suggest methods used for
postoperative stabi1i7ation.
7. To eliminate potential "ouree:s of po:sttreahnent
complication, all irradiated teeth should be
removed before the initiation of restorative care.
True or false?
8. The poBitioninl) of a palatoplmrynoeal obturator
for a cleft palate patient with palatoph>\rynge>\l
inadl;\quacy is d_b_rmif\._d by several anatomic
and functional criteria. What are the most
significant factors?
9. To be effective, the cast framework must be: a.
Rigid
b. Made of chrome-cobalt alloy
c. Thin
d. Retained by W'ire clasps
e. None of the above
f. a only
g c and d
10. The palatopharyngeal mu"c!e" that produce the
sphincteric
action
required
to
provide
palatopharyngeal competence include
11. Patients wearing metal obturators require
extensive speech therapy. True or false?
12. Describe the patient postural head positions
required to (looiot in border molding (l
palatopharyngeal obturator during the impression phase of treatment.
13. Palatal occlusal ramps can be used to guide
mandibulectoiny patients with less severe
deviation than 1hose who require a guide flange
into a more stable intercu"paJ contact position.
True or false?
14. Interocclusal jaw relation records for mandibulectomy patients must be made using verbal
guidance only A hands-on approach, similar to
that used for conventional edentulous jaw
relation records, will lead to unnatural rotation of
the mandible and an inaccurate record. True or
fal:se?
15. What is the recommended position of the head
fur a mandibulectumy patient during the
registration of jaw relation records? Why is this
position important?
REFEREN CES
1. Actldo:rny of rro_thodontic_: Gl055ury of
pro5tlwctonric
tcrn,", cd 6, J J'ra6thet Dent 71.43-112, 1994.
2. Ararnany MA: Basic principles of obturator
design for
partially
cdentuloui5
patienb.
Part
I.
Cla__ification,
J Frostl1et Dent 40:554, 1978.
3. Aramany MA: Basic principles of obturator
design for
partially edentulous patients. Part II. J Prosthet
Dent
40:656, 1978.
4. Parr GR, Tharp GE, Rahn AO: Prosthodontic
prin
ciples in the framework design of maxillary
obturator
prostheses, J Prosthet Dent 62:205-212, 1989.
:5. DeSjardinS KF: Obturator design for acquired
maxil
lary ddecl_, J Pro_thcl Dent 39;424-435, 1976.
6. Tharp GE, Kahn AO: Prosthodontic principles in
the
framework design of maxillary obturator
prostheses,
J Prosthet Dent 62:205-212, 1989.
7. Brown KE: Peripheral considerations to
improving
obturator retention, J Prosthet Dent 20:176,
1968.
8. Cantor R, Curtis TA: Prosthetic management of
edentulous mandibulectomy patients. Part I.
Anatomic,
physiologic,
and
psychologic
considerations, J Prosthet Dent 25:446-457,
1971.
Chapter
24
Removable
partial
prosthetics
9, Beumer J, Curtis TA, Marvwick MT: Maxillofacial
rehabilitation, St Louis, 1996, Ishiyaku
EuroAmerica,
10. Marx RE: Osteoradionecrosis: a new concept
of
it_ p"thophYBiolo5Y' J Qral Maxillofa9 [;urs
41,2S3
288, 1983.
11. Atkimon HF, Shepherd RW: The masticatory
move
ment5 of pfitientS fitter mfijor oral surgery, J
Prosthet
Dent 21:56-91, 1969.
12, Curti_ TA, Taylor RC, RositQno SA: Physical
problems
in obtaininB records of tb.. m"xil1ofaci"l patient
J Prostlt_t D_nt 34:539-554, 1974.
13. Ve[_o TJ, Schaaf NT: Evaluation of mandibular
movements in the horizontal plane made by
partial ffi"ndibuledomy patients: a pilot study, J
Prosthet Dent 47:310-31(\, 19152.
14 RaM AG, Goldman BM, PMr GR: Prosthodontic
pri1'\ciples in surgical planning for maxillary dnd
mandibular r_5_ctiOl1 pfitient_, J ProBthet Dent
42:429433, 1979.
1_. Shifman A, L'pl..y JR Progthodontic
management of postsur_ical SOft tissue
deformities
associated
with
ffiar5inu.1
mu.ndiln11cctomy, Part 1. Loss of th.. v..gtibuk,
J Prostl1et Dent 4B:30:3-:30g, 1992,
lIi. NaKamura SH, Martin JW, King GE, Kramer
DC: The bbial pbtc """'jar conn<>ctor i... th..
parti"l m"ndibulectomy patient, J Prosthet Dent
62:673-675, 1989.
denture
considerations
in
maxillofacial
493
17. Fish EW: Using the muscles to stabilize the full
lower
denture, J Am Dent Assoc 20:2163, 1933.
18. Fish EW: Principles of full denture prostheses,
ed 2,
London, 1933, J Bale, Sons & Danielsson.
19. Brown KE: Complete denture treatment in
patients
with reged..d mandib]es, J Prosthet Dent 21:443447,
1969.
20, Robinson JE, Rubright AB' Use of a guide plane
for tJ,.. residual fragment in partial or hemi
mandibulectomy. T Prostl1et Dent 14:992-999,
1964.
21. De_jfifdin_ RI': Occlu_ill considerations for the
partial
mandibulectomy pMient, J prosthet Dent 41:305315.
1979.
22. Martin Jw' Shupe RJ, Jacob RF, King GE:
Mandibular
po_itionin5 prosthesis for the partially resected
man
dibulectomy patient J Prosthet Dent 53:678-680,
lYH5.
23. Moore DJ, Mitchell DL: Rehilbilitilting dentulous
hemimandibulectomy patients, J Progtl1et Dent
.'.':202
206, 1976.
24. Mohl N: The role of head pU5tur_ in lllfindibulfif
po_ition. In Solberg W, Clark G, cd: Abnormal
jaw
mechanics, Chicago. 1984, Quintessence, pp
Y7-11l.
25 DuBrul FT,' Stehers oral anatomy, ed 7. St Loui5,
1970,
Mu_1.Jy, P 203.