Prosthodontic management of acquired defects of mandible123 /certified fixed orthodontic courses by Indian dental academy

INDIAN DENTAL ACADEMY
Leader in continuing dental education
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PROSTHODONTIC
MANAGEMENT OF
ACQUIRED DEFECTS
OF MANDIBLE

Table of content
 Introduction
 Review of literature
 Definitions
 Classification of mandibular defects
 Physiology of oral function following

resection
 Diagnostic Consideration for Prosthodontic
rehabilitation

 Prosthodontic management

Mandibular guidance prosthesis
Partially edentulous patient
Completely edentulous patient
 Role of implants in rehabilitation
 Summary
 Conclusion

Introduction
Management of malignant tumors involving the
tongue,

mandible,

and

adjacent

structures

represents a difficult challenge for both the
reconstructive

surgeon

and

prosthodontist.

Rehabilitation is an essential phase of cancer care
and should be considered from the time of
diagnosis. Surgical resection often creates large
defects accompanied by dysfunction,

and disfigurement while radiation therapy produces
significant morbidity and unique tissue management
problems. Speech, swallowing, control of saliva and
mastication can be adversely affected. These cosmetic
and

functional impairments should be corrected or

minimized, thereby allowing the patient to resume a
normal working and social life.

Definitions

 mandibular resection: the surgical removal

of a portion or all of the mandible and the
related soft tissues called also
mandibulectomy
 mandibular resection prosthesis : a

maxillofacial prosthesis used to maintain a
functional position for the jaws (maxillae
and mandible), improve speech and
deglutition following trauma or/and surgery
to the mandible or/and adjacent structures

 mandibular repositioning : guidance of the

mandible to cause closure in a
predetermined, altered position


Review of literature

 Prosthetic treatment of maxillofacial injuries
 JPD 1955: Lt Colonel Edwin

 Reviewed treatment of maxillofacial injuries.

He stressed the need for efficiency and
simplicity of appliances. He outlined several
designs for various types of defects. The
principles outlined by him are still followed.

 Prosthetic reconstruction of a resected

mandible
 JPD 1962: Adisman
 Described a case report of management of a

patient with resection of mandibular body
from 1st molar of one side to other side,
anterior 2/3 tongue and dorsum of tongue
sutured to mucosa of lower lip.
 Mandibular expansion with implant prosthesis
and rehabilitation with RPD was done.

 Use of a guide plane for maintaining the

residual fragment in partial or
hemimandibulectomy
 JPD 1964: Robinson and Rubright
 Described a simple guide plane from pre-

surgical impression and designed to maintain a
functional occlusal relationship as a postsurgical splint. Such a splint compensates for
uncontrolled muscular contraction.

 Prosthetic mandible of resected edentulous

mandible
 JPD 1969: Swoope
 He advocated the use of uncomplicated

appliances for treatment of edentulous patient
with partially resected mandible utilizing
fundamental principles of denture
construction. A ramp can be provided on
maxillary denture to serve as training device
for returning the mandible to a functional
position.

 Prosthetic management of edentulous

mandibulectomy patient

 Cantor and curtis
 JPD 1971
 Part I : Anatomic, physiologic and

psychologic consideration


 Presents physiologic consideration pertinent

to mandibulectomy patients discussed in
terms of functional adaptibility to surgical
insult. Deglutition, speech, mandibular
movement, mastication, respiration, salivary
control and psychologic factors have been
discussed. A classification for
mandibulectomy patients has been
suggested.

 Part II ; Clinical procedures

 Describes prosthetic principle relevant to post-

surgical conditions of radical mandibular
surgery. It describes clinical procedure to treat
the same. A clinical study of 30
mandibulectomy patients was undertaken to
make an objective assessment of the
procedures.

 Rehabilitating dentulous hemimandibulectomy

patients
 Moore and Mithchel : JPD 1976
 Describes a technique that combines crowns

with a maxillary prosthesis to guide a
dentulous hemimandible into its most
functional position after long term scarring and
deviation to the affected surgical site.


 Occlusal consideration for the partial

hemimandibulectomy patients
 Desjardin: JPD 1979
 Described various occlusal consideration for

continuity and discontinuity defects in
edentulous and partially edentulous patients.
The occlusal scheme varies from person to
person. If the continuity of the mandible can
be restored by secondary surgical management
most of the problems of the discontinuity can
be resolved.

Reduction of the median mandibulectomy with the
fixed mandibular implant.
 Goodwin et al : J oral max surg 1992

50(3):292-6
 A technique is presented whereby a median

mandibulectomy of an atrophic edentulous
mandible is performed to gain access to an
oropharyngeal tumor and is subsequently


 reapproximated with a four-pin FMI. The

procedure allows reduction of the osteotomy
site and provides intraoral implants that
increase the stability and retentive properties
of a mandibular prosthesis.


Titanium osseointegrated implants combined
with hyperbaric oxygen therapy
in previously irradiated mandibles
Arcuri et al : JPD 1997;77:177-83
 This report presents the preliminary results
of placing 18 titanium screw implants into
previously irradiated mandibles in conjunction
with hyperbaric oxygen therapy. Results. Of
the 18 implants placed, 17 (94%)


 were judged to be osseointegrated at the

abutment. The use of implants in irradiated
tissues may provide a means of enhancing
prosthetic rehabilitation while reducing the
risk of tissue trauma that may develop into
osteoradionecrosis


Arrangement of artificial teeth in the neutral
zone after surgical reconstruction of the
mandible: A clinical report
 Fukushima, sato et al: JPD 2002;88:125-7
 This clinical report describes the fabrication

of a fixed partial denture, supported and
retained by implants, for a patient with
unfavorable tongue movement caused by


movable grafted skin on the floor of the
mouth after surgical reconstruction of the
mandible. The neutral zone technique was
used, and successful results were obtained.


Rehabilitation of an irradiated mandible after
mandibular resection using
implant/tooth-supported fixed prosthesis: A
clinical report
Levin et al :J P D 2004;91:310-4
The patient presented with an unstable
removable partial denture compromised by
mandibular resection. Previous irradiation
of the mandible did not compromise the
integration of

the implants, thus enabling a fixed
rehabilitation. At first stage, a provisional
implant-supported fixed partial denture that
functioned as a positioning and guiding plane
determined the intermaxillary relationship.
The definitive metal ceramic restoration had
the same interocclusal relationship established
by the mandibular guidance device.

An implant-supported fixed prosthesis can
provide an effective functional and
predictable solution for patients undergoing
mandibular resection and irradiation.


Classification of mandibular
defects

Chalian (1985a)
 Class I Resection of the ipsilateral condyle
 Class II Resection of the ipsilateral condyle and ascending

ramus

 Class III Resection of the ipsilateral condyle and body to

midsymphysis

 Class IV Resection of the ipsilateral condyle to the

contralateral body


 Class V Total mandibulectomy
 Class VI Resection of the midsypmphysis
 Class VII Segmental resection of the body
 Class VIII Marginal or coronal resection of the

body.

Urken et al. (1991)
Urken classification of mandibular defects:
C-condyle, R-ramus, B-body, SH-symphysis (half)


Cantor and Curtis
 6 different categories based on extent of the defect and the

method of restoration in edentulous patients.
 Class I - Radical alveolectomy with preservation of

mandibular continuity
 Class II - Lateral resection of the mandible distal to the

cuspid area
 Class III - Lateral resection of the mandible to the midline

 Class IV - Lateral bone graft and surgical

reconstruction
 Class V - Anterior bone graft and surgical

reconstruction
 Class VI - Anterior mandibular resection without

surgical reconstruction


Physiology of oral functions
The nature and extent of disability depends
on the
 location and size of tumour
 Impact of radiation/ chemotherapy
 Structure and volume of tissue resected
 Design of resection
 Method of resection

Physiologic impairment
 Deglutition
 Speech
 Mandibular movement
 Salivary control
 Psychologic factors


Deglutition
 May be temporarily or permanently disrupted
 Usually returns as swallowing is a primary

function
 It can be performed with minimal muscular
function and even with loss of skeletal structures
such as mandible and hyoid bone.
 However tissue loss and reduced neuromuscular
control of oral and laryngeal structures will restrict
the anterior elevation of the floor of the mouth.

Dysfunction occurs due to
 Dennervation
 Scarring
 Radiation fibrosis
 Tongue resection
 Discontinuity defect


Speech


 Speech distortion usually occurs in

mandibulectomy patients due to impairment
of the articulating mechanism or resonating
chambers.
 Reduction in tongue size or mobility
 Displacement of mandibular fragment will
cause asymmetric functioning of the tongue
 Scarring of lower lip can interfere with
sound production.

Mandibular movement and mastication
 There is alteration and restriction of

mandibular movement.
 The remaining mandibular segment will
retrude and deviate towards the surgical
side at rest position. Upon opening the
mouth this deviation will increase leading to
angular pathway of opening and closing.


 Loss of proprioceptive sense of occlusion

leads to uncoordinated less precise
movements, loss of masticatory muscles on
surgical side will result in significant
rotation of mandible upon forceful closure.


Frontal plane rotation


Occlusal relationship


Saliva control
Drooling can occur due to
 Restricted tongue movement
 Difficulty in swallowing
 Absence of labial, buccal and lingual sulci
 Scarring of orbicularis oris
 Loss of sensory awareness

 Xerostomia
 Reduced salivary flow which is thick and

ropy.
 Degeneration of salivary glands due to
irradiation
 Denture retention, tissue tolerance and taste
adversely affected

Radiotherapy
 Acute Sequelae
 salivary gland pathoses
 acute parotitis, irreversible changes (flow

rates, compositional alterations)
 oral mucositis
 Infections of mucosa and periodontium
 dysgeusia

 Chronic Sequelae
 salivary gland pathoses
 acute parotitis
 irreversible changes (flow rates,

compositional alterations)
 dental alterations : rampant caries,
demineralization
 osteoradionecrosis

Psychologic factors
 Distortion of self image
 inablity to communicate,
 shifting family and vocational roles require

psychologic counseling


Diagnostic Consideration for
Prosthodontic rehabilitation


Location and extent of mandibular
defect
 Continuity defect
 Discontinuity defect


Continuity defect
 Radical alveolectomy
 Reduction in stability of prosthesis due to

loss of vertical ridge height and vestibular
depth.
 Vertical discrepancy between level of
residual osseous support an opposing
dentition at the level of occlusal plane.


Discontinuity defect
 Rule of thumb: The further anterior the

defect the more disfiguring and functionally
debilitating it is likely to be.
 Defects of symphyseal region always

require surgical reconstruction before
prosthodontic therapy can be effective.


 Defects of posterior mandible can be

restored to near normal mandibular mobility
with immediate or delayed surgical
reconstruction.


Presence of remaining natural teeth
 Teeth are crucial to stability of prosthesis.

Prognosis improves as no.. of teeth
increase.
 Teeth present bilaterally


Rotation and deviation of mandible
 Deviation towards the defect side occurs

due to loss of tissue and primary closure
drawing the margins together.
 Loss of continuity also results in inferior
rotation of mandible


Results of deviation and rotation are
 Facial disfigurement
 Loss of occlusal contact
 Loss of ability to bring the lips together for
salivary control.


Mouth opening
 Many patient experience limitation of

mouth opening after mandibulectomy due
to surgical trauma and scar formation
 Sufficient mouth opening to allow dental
access and making of impression is
paramount.
 Prevention of scar tissue formation by
stretching exercise soon after surgery

Vestibular extension
 Normal vestibule is important to alow for

extension of flanges for maximum support ,
stability and perepheral seal asociated with
retension.
 Loss of vestibular depth adversely affects
prognosis
 Secondary surgery – vestibuloplasy must be
done even if continuity of mandible exists.

Tongue mobility
 Frequently surgical wound is closed by

suturing remaining tissue of floor of mouth
or tongue to buccal tissue. This limits
mobility of tongue.
 Affects speech, swallowing, mastication,
prosthesis control and control on food
bolus.
 Tongue mobility must be evaluated
 Lingual vestibuloplasty, Speech therapy

Prosthodontic management


Mandibular guidance prosthesis
 Begins 2 weeks after surgery
 Presence of teeth essential. Excessive lateral

forces generated during guidance of
mandible can dislodge complete denture.
 Can be constructed on maxilla or mandible
 Once acceptable occlusal relationship is
attained guidance prosthesis can be
discarded.

 1 Obtain maxillary and mandibular

impression and pour the cast
 2 Wax interocclusal record obtained by
clinician by guiding mandible into best
possible interocclusal relation
 3 Cast mounted on articulator and studied
 4 Occlusal equilibration done

 Diagnostic cast of mandible is surveyed and

RPD design outlined.
 Engage maximum no.. Of teeth. Guidance
flange extended from continuous clasp on
buccal aspect .
 The guidance ramp must extend superiorly
in a diagonal manner to allow for normal
overlap of maxillary and mandibular teeth.

 If an acrylic ramp is planned a retentive

mesh must be placed extending from
continuous buccal clasp on non-defect side.
 To decide angulation of ramp a second wax
record obtained with posterior teeth
separated upto 3mm and mandible deflected
maximum towards non-defect side is
obtained and used to articulate cast.
 Wax pattern of framework and flange s
designed and casted

 If acrylic ramp is planned, then

autopolymerizing resin at dough stage is
attached to retentive mesh placed in patients
mouth and mandible guided repeatedly into
desired position.
 Resin manipulated to extend 7-10mm
superiorly.
 Prosthesis removed, allowed to polymerize,
trimmed and polished.

 Resin ramp can be periodically assessed

and adjusted unlike metal ramp


 Maxillary guidance ramp is made of acrylic.
 The full palatal coverage prosthesis is

constructed and tried in the mouth.
 Autopolymerizing acrylic resin is added to
palatal aspect along the lateral and anterior
border on the non-defect side.
 The prosthesis is replaced in mouth and
mandible manipulated to desired position
thus establishing a index in palate.

 The movement is repeated several times

until resin polymerizes
.
 Prosthesis is removed and polished.


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Prosthodontic management of acquired defects of mandible123 /certified fixed orthodontic courses by Indian dental academy

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