management of mandibular defects........

prosthodontic management of mandibular defects

2. Contents
Introduction
Challenge
Classification of mandibular defects
Complications

Factors affecting treatment of mandibulectomy
patients

Relating surgical and prosthetic considerations in
mandibulectomy patients

Treatment plan

Management of mandibular deviation
Implant supported prosthesis
Conclusion

References

3. Introduction

oo: A D

4. Mandible ts a single bone that creates

Peripheral boundaries of the floor of
mouth

Facial form (Lower t
Speech

Swallowing
Masticatton
Respiration

Disruption of the mandíble has the
potential to disrupt any of these

5. Rehabilitation of mandibulectomy

patients should therefore consider both

form and function .
AS

Tai

6. Surgical resection of tumor often
includes a partial mandibular
resection, a partial glossectomy, a
parttal resection of the floor of the
mouth, and a radical neck dissection.

The extent of surgery and the effects of

radiation therapy and chemotherapy
determíne the amount of

rehabilitation needed by a given
patient.

7. Oral reconstruction of the patient who
has a partially resected mandible is
one the most challenging procedures
confronting the maxillofacial

8. q
| tt sn
Ey ‘pt

defects

9. Mandibular Defects
Fe

==

Developmental Acquired
R 74 ES
(Mandibular 5 EN
prognathism/ Pathology
Trauma
retrogwathism) | (tumors),
(Fractures)
Surgical Mandibulectomy

Gunning splints

10. Ace to etiology - Laney (1979)

1. Acquired:

- Marginal
- Segmental
a) Antertor body
b) Lateral to
midline
- Body only
- Ramus
- Body with
disarticulation

__ eshrFAEAI

11. 2. Congenital
- Incomplete formation
- Incomplete ossification
e.9.) hypoplasia,
mandibulofacial
dysostosis,ete

3. Developmental
as a result of postnatal insults

e.9.) trauma during birth,
surgery, etc

12. Ace to amount of resection E

* Continuity defect L OS Siscontinutty defect

(marginal resection) (segmental resection)

- Inferior border and tts - Complete segment of mandible from

continuity preserved alveolar crest to inferior border
removed

- No deviation
- Mandible deviates to resected side

- Less facial disfigurement
- Marked facial disfigurement

- Occlusion rarely changed
- Occlusion altered
- Can be :- anterior defect

posterior defect - Can be :- Lateral discontinuity defect

midline discontinuity

as ap ee

13. Class 1

14. TISSUES RESECTED

- Portion of alveolar process and body of
mandible

- Lingual and buccal sulcus mucosa

- Portion of base of tongue and
mylohyoid muscle

- Lingual and inferior alveolar nerves

- Sublingual and Sub maxillary
salivary glands

- Sometimes anterior part of digastric
muscle

FEATURES

1. Least debilitating.

2. Can raise the floor of the mouth causing reduction in
tongue mobility.

3. Ability to shape and control the tongue may be Lost
due En Loce nt come i¡nerincio muerlee.

15. elass 26

Lateral resection of mandible distal to
cuspia

16. TISSUE RESECTED
- condyle, ramus and body of mandible distal to cuspid

- mylohyotd, hypoglossal,ant belly of digastric,

internal
pterygoid,masseter,extermal pterygold,

pharangoglossal
§ palatoglossal muscles, most of intrinsto

muscles of
tongue.
- hypoglossal , Lingual and inferior alv nerves

- adjacent buccal and lingual mucosa

FEATURES
1 Speech, swallowing, saliva control, manipulation of food impatred.

2. Facial disfigurement apparent
3. Disarticulation and Loss of muscles of mastication will hampered

mandibular movements
4. Taste ‚sensory and motor Losses more extensive as compared to

class 4

17. Class 3

Lateral resection of the manaible to
midline

18. TISSUE RESECTED
all those described in class 2 in addition to the
anterior portion of the mandible,

gentohyota,

genioglossus, remaining portion of
mylohyoid

muscle with Lingual and buccal mucosa.
FEATURES

1. Restricted tongue mobility due to Loss of tip of tongue and
gentoglossus muscle

2. Speech, swallowing,saliva control and manipulation of food
severely restricted.

3. Facial disfigurement is worse due to loss of anterior part of
mandible

4. Disarticulation and reduction in amount of basal bone
reduce procthodoutie prDanpsis.

19. Class 4

Lateral bone graft § surgical
reco Lou

20. + Lateral bone and split thickness skin or
pedicle graft caw be performed on patients
who have had:

- radical alveolectomies

- resection of mandible distal
to cuspid

with or without
disarticulation.

+ Three types of bone grafts are possible
1. Mandibular augmentation procedures.

2. Bone graft that connect a residual
condyle with the Larger mandibular
fraament.

21. CLASSES:

Anterior bone graft gsurgícal
reco i

22. TISSUE RESECTED
- antertor portion of the mandible
- Large bilateral portions of mylohyoid,

gentohyota
gentoglossus and anterior digastric muscles
- bilateral lingual and inferior alv nerves
- bilateral submaxillary and sublingual salivary
glands

- mucosa of Lower Lip
- anterior floor of mouth
- ventral surface of tongue

The mucosa retaíned in the labial and buccal regions ts sutured
to the

residual stump of the tongue and a krischner wire is often
positioned to

maintain the mandibular fragments,

23. Class 6

It is similar to a class V patient, but
the continuity of the mandible has
not been restored surgically. Because
each Lateral fragment moves
independently, the prognosis for a
removable prosthesis ts poor and
fabrication is not recommended

24. Ns Y e ii k A LY

25. With only one half or two thirds of the
mandible remaining, stability, support
and retention of the mandibular denture
are compromised.

Bue to radiation ara either prior to or
after SUN the oral mucosa is
atrophic and fragile, predisposing to
soft tissue irritation and ulceration.

The reduction in saliva output, and the
thick mucinous nature of the saliva that
remains after therapeutic Levels
radiation, immpairs retention and

26. The angular pathway of mandibular
closure induces Lateral forces upon the
dentures, which dislodge them.

The deviattow of the mandible creates
abnormal jaw relationships. The
abnormal profile and position of the
mandible im relation to the maxilla
may prevent tdeal placement of the
denture teeth over their supporting
structures.

The impairment of motor and/or
sensory control of the tongue, Lip,
and cheek tmpatrs the ability of the

27. Factors arrima

patíe mts

28. Location € Extent of Mandibular

Defect
Margiwal alveolectom

-Least debilitating

-Main problems - Loss of vertical ridge
height and vestibular depth

-Vertical disorepancy is most important

when prosthesis supported by de
implants ts considered.

29. Marginal defects have better prognosis
than discontinuity defects.

The farther anterior the defect, the more
disfiguring avd functionally
debilitating GES: LiRBEHNED ve.

Reason: Loss of key muscle
attachments (gentoglossus and
gentohyota) Located in anterior
mandible that control tongue
function and mobility.

30. * Defects of the symphyseal region are
most debilitating and difficult to
treat.

* Greatest facíal disfigurement.

* Surgical reconstruction necessary or
at Least Sinne ation

31. Mawdibulectomy defects in the molar
regton

32. 2. Presence of remainina natural
teeth/pre=existina implantes

Patients after mandibulectomy present with few or
wo

remaining natural teeth.

-Pts with greatest risk of sq cell carcinoma are
heavy

users of tobacco and alcohol and Lack good oral
hygiene.

-Strong relationship between tobacco § periodontal
disease

-Teeth are usually extracted prior to radiotherapy to
prevent complications such as osteoradioneerosis.

Greater the number of teeth ,better the prognosis.

33. remaining natural teeth in
linear relationship are unlikely
to províde adequate abutments
for prosthesis than teeth arranged
in two ae si =

34. A maxillary complete denture will
function well for a mandibulectomy
patient against a reconstructed
mexdibiher Aéwithblevet residual proximal

mandibular stump against Ehe posterior
maxilla vc

i
denture fav

when a guide flange prosthesis is wa Sea
for treatment of mandibular deviation .
Pressure from Guide flange can dislodge the
nAeputure

35. 3,Dearee of post mandibulectom
rotationand déviation

Mandíble deviates towards the defect and rotation
of mandibular occlusal plane inferiorly.

36. * During mandibular closure, mandible
rotates around occlusal contacts on
un-resected side, and remaining teeth
ow resected side drop further out of
occlusion. This movement is called
FRONTAL PLANE ROTATION.

37. * Deviation: Due to

* Primarily due to loss of tissue involved in
surgícal resection.

Rotation: Due to

- Pull of the suprahyoid muscles on the residual
fragment
causing inferior displacement and rotation
around the
fulcrum of the remaining condyle.

- Gravity. Loss of anchorage of elevator muscles.

Sequelae
* Facial disfigurement
* Loss of occlusal contact

38. Prosthodontic prognosis in such patients can
be improved by early post resection physical
therapy to reposition the mandibular
fragment to a more normal position and to
minimize scar formation that will make
deviation more severe.

Should be carried out as early as possible.

AT VE ER in APR Ot
Gea APE LL LR

Can be tn the form of

1.Physical therapy carried out by the
patient himself

39. 5.Avatlable mouth

openiwa
Trismus -due to surgical trauma

Physical therapy should be started
immediately.

Scar tissue formation will further reduce
mouth

opening.

Simple test to check mouth opening: Insert a
stock

mandibular impression tray in the mouth.tf
this cannot

PA E A eee eee ft) 5 Patel mu

40. 6.Functional limitation of

tongue
- Frequently the surgical wound ts closed by
suturing
the remaining tissues of the floor of the mouth
or
tong!

41. This compromises: - Speech
- Swallowing
- Mastication
- Control of food bolus

- Ability to control removable
prosthesis

- Lingual vestibuloplasty and skin or mucosal
grafting can
be used to improve tongue mobility

Evaluation of tongue mobility

- In patients whom anterior resection has been done,
ability to lick the Lips when the artificial prosthesis

42. In such cases consideration ts given to Lowering the
antertor

occlusal plane or arranging the teeth slightly
lingually.

Speech therapy

Loss of innervation will compromise tongue function and
prognosis of prosthodontic rehabilitation.

If lingual nerve is sacrificed during resection, the tongue on
the

defect side will permanently remain without any feeling.
Loss of sensory capability:- Affects speech

Mastication

Prosthesis control

Loss of sensory imnervation of the buccal mucosa (Long
hurrnl

43. Z.Compromise of vestibular

extensions
vestibular depth ts critical for stability and
peripheral
seal

lt is also. critical when mandibular ponla is

44. g.SRín 9 rafting

Skin grafts are used for surgical reconstruction
either as Lining for the surface of resected soft tissue
or as part of skin and connective tissue grafts such
as pedicle flaps, free flaps etc.
Advantages
1. Effective Load bearing tissue.
2. Caw withstand pressure and chafing from
prosthesis.
3. Protects underlying bone and connective tissue
well due to

rapid turnover of keratin producing cells.

Disadvantages
1. No sensory Ínnervations.

45. 9 .Radtation therapy

Careful treatment planning ts
required for patients with radiation
therapy

Irradiated tissue ts fragile ‚sensitive
to manipulation, dessicated,slow to
heal, prone to infection and at risk of
osteoradionecrosís

46. 10. Altered anatomic relationships
following
restoration. of mandibular contimuity
- Reconstruction of anterior defects

Most difficult situation for grafting and frequently
results in a

graft that ts defieient anteriorly.
- Results in a severe Class 2 like situation.

The prosthodontic difficulties seen in rehabilitating such
a patient

are:-
- Inabílity to provide proper Lip support.

- Speech problems associated with mandibular
dentition

placed too far lingually.

- Imability to control food bolus due to lack of
motor

47. - Excessive display of mandibular teeth due to patients
imability

to maintain normal Lip posture.
- Bifficulty gaining adequate space for prosthesis
placement

without encroaching om function of tongue.

- Misalignment of remaining un resected mandibular
fragments

awd resultant relationship between maxillary and
mandibular

teeth.

- Reconstruction of posterior defects
- More predictable from prosthodontic point of view as
compared
to antertor defects.
= The mediolateral positon of the graft is frequently seen

> ar

48. 11. Previous experience with
removable prosthesis

Indicator of how successful
rehabilitation will be, particularly
edentulous patients

49. Relating surgical considerations to
prosthodontic treatment

Marginal mandíbulectomy
Soft tissues are mainly used to reconstruct
marginal =.
mandibulecto mies

- - Pedicle flap
- Micro vascular free flaps (MVFF)

Skin grafts are ideal for prosthetic reconstruction.
However when soft tissue bulk is required or
reeipient bed is

previously irradiated micro vascular free flaps are

Pas dun D

50. Discontinuity defects
Previously soft tissue Local flaps (mainly the residual
tongue sutured to the border of the defect) and
pedicle flaps (pectoralis muscle) were used.

MVFF have revolutionized the treatment of
discontinuity defects.
Micro'Vascular iaa ESO PUTA LEA from:
1.Fibula- most common
2.!liac crest

Sptt

Soft tissue MVFF are obtained from
1.Forearm
2.Rectus muscle

51. Manalbular mal position after bony
reconstruire to:

1. Minimal proximal mandible ow the surgical side to attach the
bone graft.
2. Mandibular segments are wot stabllized and maintained in
their
pre-operative relation to each other during grafting
procedures.

3. Delayed eo may not. be able to overcome scar
tissue

formation completely.

4. The bone grafts us
have

some inheren
(Cacks heia andíble)

iliao orest graft

52. «fs
CA

PROSTHOBONTIC
REHABLITATION

53. Anal st neh.

TS £
& a E > J LA

54. TREATMENT PLAN

* Exercise regimen
* Reconstructtow

* Definitive Guidance Prosthesis.

55. Treatment optio WSs

* Conventional complete denture

: Implant gu Me Pay
over di 6

56. Impressions

Maximum extension and tissue
coverage should be recorded with the
preliminary impression

Irreverstble hydrocolloid is us ith
aw altered/secttowal stock t

Conventional border molding and
Master impression ts used to achieve
better pertpheral seal.

57. Prima ry impression

59. Secondary impression
with border molding

60. Processed bases

* Necessary due to Loss of supporting bone ,unusual
intra-oral contours, gross mal position of occlusal
contacts.

* Allow the deta iat ie a of the ve of the
final prosthe va the b
lingual t

* Recording maxillo-mandibular relationship with
processed bases evaluate
retention and st ng WAX rims
or dentition.

61. * Significant Loss of alveolar bone as well as rotation
and deviation of the mandible postoperatively make it
necessary for the record bases to be as stable as
possible during maxillo mandibular records.

* Extension beyond the periphery of the prosthesis may
be

required to support the Lip. To add stability to the
prosthesis, occlusal contact may need to be
significantly buccal or

Lingual to normal anatomic Landmarks that usually
denote the occlusal table.

* Pts who have tmplant retained prosthests should have

retentive elements incorporated tn the processed
hacec Thic

62. Jaw relation

* Centric relation does wot exist tn
partially mandibulectomy patients
with discontinuity defects because
there ts only one condyle to guíde the
mandible.

* Interestingly they do have
proprioception for a repeatable area
but not a repeatable point contact
when asked to open wíde and close the

63. Record bases are constructed tn the
usual way with the following
exceptions:

In the maxilla, the wax rim used to
record the centric occlusion
registration record ts widened on the
un resected side towards the palatal
síde tw order to account for deviation
of the mandible.

64. Vertical dimension of occlusion

is difficult to determine due to

mandibular deviation and

impaired motor and sensory
netion v

Mm :

nould rely on
Lip competey

ce, facial appearance

65. Centric occluston registration ts done
with wax, plaster or any other
recording medía.

The patient ts instructed to move the
mandible as far as possible toward
the untreated side. Then patient was
asked to close with his own muscular
force when the mandible was

manually guided. This records a

fu ‘Lo ‘

66. Teeth selection and
arranaemen

* Artificial denture teeth ee degree

cuspal angulations are selected and
arranged to achieve monoplane
occlusion and to allow for Lateral
freedom of mandibular movements.

With the Lingual inclination of the
resídual mandible, and with elevation
of the buccal shelf, placement of
posterior teeth to the buccal of the
restdual alveolar ridge centers the
forces of occlustow more favorably

67. * After all the mandibular teeth and

the maxillary teeth have been
arranged, ramps are developed for the
maxillary prosthesis in base plate
wax. These ramps usually 5-10mm
wide and should provide 2-4mm
horizontal overlap with the
mandibular posterior teeth.
Depending upon severity of deviation,
the ramp on the nonsurgical side
usually extends palatal to the
maxtllary alveolar ridge, and the
ramp on the surgical side extends

68. Palatal Augmentation
Prosthests

* These patients have difficulty in
valving the tongue against the palate
for appropriate speech sounds and to
manipulate food bolus in mastication
and swallowing.

* This is due to loss of tissue bulk and
motor movement of the tongue.

69. * This prostheses involves shaping the
contours of a palatal base plate, either
retaíned by maxillary dentition or
maxillary complete denture.

* In normal tongue-palate relationship,
the palate CUPS around the tongue at
rest and in function.

70. * Hence contours of palatal augmentation
prostheses should also CUP around the
residual/deviated tongue.

* Repeated movements of tongue will allow
the clinician to add wax to the base plate to
establish occlusal contact.

* Thickness ts increased until the tongue
contacts the palate iw swallowing.

71. Gast partial denture

* Indicated for patients with marginal
mandibulectomies

* ideal prosthesis bearing surface is
split thickness graft ; it ts thin,
firmly attached to the mandíble and
will mot move with movement of
tongue , floor of mouth or cheek

72. Pick up impression or functional reline
ts weeded

Removable framework should follow
routine parameters of design related
to support, stability and retention.

73. Marginal mandibulectomy
patient resurfaced with skin

graft

74. Fabrication of framework

75. Sectional Denture

* Two part denture designed to engage and
utilize opposing proximal undercuts on
mestal and distal abutment teeth, which
will result in positive retention in both
vertical and Lateral direction often without
incorporating a conventional clasp.

* Each part of the denture will therefore have
its individual path of insertion and once in
position the part will be maintained in
position by means of a Locking bolt to form
a whole unit.

- The technical construction of st such an

EE AAA ÊT ICAA TENA «A x

76. ae 3 zz

Management of mandibular

77. Methods to minimize
deviation

skin grafts and flaps for

eof

ner ie LANCE he

78. IMF

* Aramany and Myers advocated the
use of inter maxillary fixation with
arch bars and elastics for 5-7 weeks
immediately after surgery.

This type of fixation maintains the
residual mandible in the proper
maxillo mandibular position and
permits healing of the defect and the
associated scar formation with the
teeth in occlusion.

79. "If Inter maxillary fixation ts
used tw tmmedtate post-
operative period,
very little muscle retraining
may be needed.

* The degree of deviation seems
to be inversely proportional to
the lenath of time the

80. Gunning splints can be
used for IMF tn edentulous
pat _ EE

81. VACCUM FORMED PVC
Se CINES

* Following the removal of inter
maxillary fixation, early progression
to a more definitive appliance can be
factlitated by using an intermediate
Vacuum formed PVC appliance.

* Upper § Lower splints are fused
together tw maxtmum inter cuspation
by interposing a further Layer of the
heated polymer.

82. * Jaw movements are thus gently
restrained and guided by the soft
plastic splint making it comfortable
for the patient to wear.

* The appliance may also be worn at
night-time

* This appliance has a relatively short
shelf life and weeds to be replaced by a
more definitive acrylic or metal
appliance once the patient adapts to

83. On closure of jaws the Lower teeth ano
mandible are a easily guio
into the Lower hale of the splint Oy its
flanges and indentations into the correct

A
tded

84. MANDIBULAR GUIDANCE
PROSTHESIS

In discontinuity defects mandibular
gutdance therapy can be instituted to
retraín the patient’s neuromuscular
system to provide an acceptable
maxillo-mandibular relationship of
the residual portion of the mandible
which permits occlusion of the
remaining natural teeth

85. Classification
1) Palatal based guidance prosthesis

* Maxillary inclined plane prosthesis.

* Positioning prosthests with palatal
flange

* Widened maxillary occlusal table

2) Mandibular based guidance
prosthesis

86. Maxillary inclined plane

© The prosthesiß (2 A! Using inter
proximal ball clasps or adam's clasps.

* Mandibular closure results in the
progressive chats a the remaining

87. Positioning prosthesis with palatal

E fla Kine ;

* Patients who are able to use their pre
surgical inter cuspal position after
mandibular resection often complain
of inability to prevent the mandible
from deviating towards the defect
side during sleep.

On awakening they have difficulty
reestablishing normal occlusal
contact.

88. * Flage extending from palate inferiorly into
the Lingual vestibule between Lateral border of
tongue § lingual surface of the mandible can
be formed in the mouth with auto
polymertzing acrylic resin.

* Prevent meatal deviation of un resected
mandible even when the mouth ts open.

* The flange should contact only the lingual
surfaces of mandibular teeth and it should
not tmpinge on the lingual mucosa of the
mandible throughout the opening and closing

90. widened maxtllary occlusal

able

* patients who cannot attain the ideal
medio Lateral position of the
remaining segment and an acceptable
occlusal contact of the teeth, in spite
of the use of various guidance
prostheses, a palatal ramp or a
widened maxillary occlusal table
using double row of teeth may be
used.

* Provide a surface aaatwst which the

91. Palatal Ramp to widen
wmaxtllaru occlusal table

93. Mandibular Lateral guide flange
prosthesis
* used in patients who can achieve
proper medio Lateral position of the
mandible but cannot hold that
position for ages D tlöatlon:

94. * The guide flange is attached to a cast
mandibular removable partial denture.

* tt caw be either molded tw wax at the try-in
stage and processed tw clear acrylic resin
or a heavy wire Loop may be used.

* The guide flange is extended into
maxillary muco-buccal fold supertorly §
diagonally on non defect síde without

As

96. Advantages of
reconstruction using osseo
integrated implants

* They provide stability and retention for the
prosthesís.

* They allow the use of a fíxed or removable
prosthesis.

* tt avoids the preparation of remaining teeth
as abutments.

* It avoids the problems of the tissue borne

prosthesis.

97. * For many resection patients, usually
2-3 properly positioned implants are
needed.

* Implants should wot be placed close
to the border of the resected mandíble
because the bone in this region may
be necrotic or poorly vascularized,
secondary to the previous surgical
procedure.

98. Implants placed in the
graft e months after

99. UWLLATEVAL partial AENTKYE
retained by ball
attachments on the implants
and one clasp on the
remaining dentition

100. Final prosthesis

102. * Prosthodontíc success in the
mandibular resection patient is
closely allied with the surgical
reconstruction.

* MVFFs has revolutionized
reconstruction of the mandible and
contiguous oral structures.

103. * Prosthodontic modifications to
routine prosthodontic procedures are
wecessary to compensate for deficits
that are wot correctable with surgical
reconstruction

* The maintenance of facial form,
prevention of tethering of intraoral
tissues have greatly enhanced the
results obtained by prosthodontic

104. eferences

Ackerman A) The prosthodontic management of oral and
facial defects ) Prosthet Dent,1955;5:413-432

Scannel JB Practical considerations tw dental treatment of
patients with head and neck cancer) Prosthet
Dent,1965;15:764-778

Kelly EK Partial denture design applicable to the
maxillofacial patient) Prosthet Dent,1965;15:168-173

Swoope CC Prosthetic management of resected edentulous
mandibles ) Prosthet Dent,1969;21:197-201

Cantor R and Curtis TA Prosthetic management of edentulous
mandibulectomy patients Part 1) Prosthet Dent,1971;25:447-
455, Part 2) Prosthet Dent,1971;25:547-555, Part 3)
Prosthet Dent,1971;25:671-78.

105. Armany MA and Meyers EN Intermaxillary fixation following
mandibular resection) Prosthet Dent,1977;37:437-443

Desjardins RP Occlusal considerations in partial
mandibulectomy patients) Prosthet Dent,1979;41:308-311

Shifman A and Lepley JB Prosthodontic management of
postsurgical soft tissue deformities associated with marginal
mandibulectomies ) Prosthet Dent,1982;48:178-183

Clinical maxtllofactal prosthetics, Thomas D Taylor;1* edition

Maxillofactal prosthetics, Varoujan A Chalian

Maxillofacial prosthetics, postgraduate dental hand book
sertes, Vol + William R Laney

Removable partial prosthodontics,Alan B Carr;11" edition

Clinical removable partial prosthodonties, Kenneth L Stewart;2"