Mandibular defects and reconstruction

1. Acquired Mandibular Defects

2. Malignancies of maxillofacial region are most common
etiology for the acquired defects of that region. Oral
squamous cell carcinoma is the most common cancer in
India, and its prevalence ranges around 45% of all cancers.
Unfortunately, most of these lesions are diagnosed at a late
stage and requires surgical resection along with adjacent
anatomical structures such as mandible, floor of the mouth,
tongue, etc.
Lose of mandibular continuity results in cosmetic,
functional and psychological discomfort for the patient. If
condylectomy has been performed the prime most difficulty
encountered is deviation of mandible towards the defect
side, and inferiorly.
Introduction

3. A classification of mandibular defects based
on functional as well as aesthetic factors is
presented. By taking into account the
difficulties in restoring form and function
and not simply relying on traditional
anatomic landmarks.
Classification

4. #According to laney (1979):
*Based on etiology:
Acquired:
1- Marginal.
2- Segmental:
A- Lateral to midline:
* Body only.
* Ramus-body disarticulation.
B- Anterior body.
3- Subtotal.
4- Total.

5. # according to boyd and colleagues classification (HCL):
H- Lateral defects of any length up to midline including condyle.
C- Defects involve central segment containing 4 incisors and 2
canines.
L- Lateral defects excluding the condyle.
# according to soft tissue component (OSM-SM):
O- No skin or mucosa.
S- Skin.
M- Mucosa.
SM- Skin and mucosa

6. A- Associated with defects of tongue:
1- Cosmetic disfigurement.
As tumors of the tongue.
Disabilities associated with mandibular defects

7. 2- speech:
*Speech affected by the portion resected in tongue and loss of
motor and sensory innervation that cause impaired mobility of
tongue.
3- Deglutatition:
*Speech can be affected by the extend of surgery and method of
closure.
4- Discrepancies in mandibular position:
A- Mandiblar deviation
B- Frontal plane rotation.
5- Drooling of saliva.
6- Trismus.
7- Disabilities due to resection of vital stuctures.

8. Surgical modification that improve prognosis
1- Re-establishing the continuity of mandible:
A- Approximating the two ends and holding in position with fixation wire
B- Mandibular reconstruction :
Usually at the time of initial resection, mandibular continuity can be maintained
using rigid fixation with tray and bone graft
2- Sectioning in ramus area : ( edentulous )
Condyle and ramus should be removed because if the condylar coronoid
fragment remains ,it`s often retracted medially and anteriorly , and approximate
the maxillary tuberosity.
3- Sectioning in dentulous portion :
As in a maxillectomy , bony cut through the dentulous portion of the mandible
, should be intraseptal rather than interproximal
This will result in higher level of bone for the adjacent tooth to surgical defect
, making tooth more suitable as a partial denture abutment.
Management of mandibular defects

9. Case presentation
A 27-year-old Thai female with chief complaint of difficulty in chewing food was
referred to the Maxillofacial Prosthetic Service.
Her previous history revealed Ameloblastoma of the posterior left mandible for
which segmental mandibulectomy was performed and the initial reconstruction
was performed with reconstruction plate with multiple occasions where there were
infections and exposures of the reconstruction plate.
Final reconstruction was performed with an iliac crest bone graft in 2009 after a
tumor free period of 4 years.

11. Extra-oral examination showed
facial asymmetry with deficiency
of hard and soft tissues on left
mandibular defect region compared
with the right side (Figure 2).

12. Intra oral examination showed maxillary
arch fully dentition with mandibular
partially edentulous, anterior cross-bite
overjet of 1 mm, deep bite of 5 mm in
centric occlusion (Figure 3).
the defect area was covered with a split
thickness skin graft which had healed
completely but had a shallow vestibular
sulcus (Figure 4).

13. Radiographic examination demonstrated reconstruction of the
defect with an iliac crest bone graft. However the patient still had
screw remaining on defect side (Figure 5).

14. Primary impressions were taken with irreversible hydrocolloid
impression material. Study cast was poured and surveyed, and
then special tray was fabricated with using lower study model.
The teeth were prepared as the design and the secondary
impression along with the edentulous defect side was taken using
a special tray and polysulphide light-body impression material. A
lingual bar was chosen as the major connection design due to
adequate sulcus depth, a cingulum incisor rest seat was made on 1
and mesial rest on 4 and 7, and distal rest on 5 respectively.
Treatment Plan

15. On 7 the retentive arm was made on lingual aspect as there was absence of
undercut on the buccal aspect, Mesio-occlusal rest on 4 acted as an indirect
retainer. The frameworks for the removal partial denture were fabricated from
a cobalt-chrome-alloy (Figure 6).
The frameworks were evaluated and adjusted intra-orally for fit, retention,
and stability.

16. The denture was fabricated using heat polymerized acrylic resin following
conventional laboratory procedure. After polymerization the denture was finished,
polished and delivered (Figure 7).

17. After patient was able to chew well and was satisfied with the results and she had no
complaints during 6th month of follow-up. Furthermore there was no recurrence of
Ameloblastoma on defect side (Figure 8).

18. Marginal or conservation resection causes less complication in form
and function of the mandible such mandible deviation to defect side,
difficulty in control of saliva, swallowing, speech, and severe
cosmetic disfigurement, Frontal plane rotation. Conservative
management may be beneficial for rehabilitation as there is minimal
loss of structures. However, the choice of conservative mandibular
resection holds the risk of unclear resection margins especially with
advanced Tumors.
Discussion

19. Surgical and prosthodontic rehabilitation of the mandibulectomy
patient can provide satisfactory results, improving the oral functions
of the patient which overall makes a positive impact on the quality
of life for the patient. However proper treatment planning pre and
post surgery is necessary to obtain the most optimal results.
Conclusion

20. THANK YOU

21. Done by:
1- Eslam Mohamed Jahlan. 43548
2- Ahmed Abdel Nasser. 37433
3- Mohammed Magdy. 15236
Represented to:
Prof.D. Sahar Khalaf