Post-Maxillectomy Prosthesis - 10 Marks (Final Year ENT PG)

1. Introduction / Definition

• Speak (eliminates hypernasal speech)
• Chew and swallow effectively
• Breathe without nasal regurgitation
• Maintain aesthetics

2. Classification of Maxillectomy Defect (Brown's Classification)

• For Level I and II defects: prosthetic obturation works well
• Level III+: free tissue transfer preferred; prosthetic outcome worsens significantly - Scott-Brown's, p. 543

3. Pre-Surgical Assessment (Pre-prosthetic Planning)

• Early consultation with prosthodontist before surgery
• Detailed oral examination; panoramic OPG mandatory
• Pre-operative dental impressions and cast models in all dentate patients
• Marking the cast along planned alveolar resection margins (Figure 31.3 in Scott-Brown's)
• Decision on osseointegrated implants - plan if anticipated retention difficulty
• Bone cuts should ideally be made through edentulous regions or dental extraction sockets to preserve periodontal support of abutment teeth
• Palatal mucosal incisions should be lateral to bone cuts to create a keratinized mucosal flap that improves prosthesis stability
• Risk factors (smoking, alcohol) should be addressed before complex rehabilitation

4. Types / Stages of the Obturator Prosthesis

A. Surgical (Immediate) Obturator

• Placed at the time of surgery, directly in the operating theatre
• Made from pre-operative impressions on a plaster model
• Acts as a surgical dressing / pack; supports the surgical flap
• Prevents nasal contamination immediately post-op
• Allows early speech and swallowing
• Simple clear acrylic cover plate if time constraints exist pre-operatively
• May incorporate dental clasps or circum-zygomatic loops for retention
• Maintained for 10-14 days until the first post-op visit

B. Interim (Transitional) Obturator

• Placed 10-14 days post-operatively when surgical obturator is removed
• Modified repeatedly as surgical cavity contracts and heals
• This phase may extend 2 to 24 months
• Allows access for surveillance during healing
• Made of acrylic with soft liner adjustments; teeth can be added progressively
• Important for maintaining oro-nasal separation and preventing trismus

C. Definitive Obturator

• Fabricated once healing is complete (typically 6-12 months post-surgery + post-radiotherapy)
• Long-term prosthesis optimized for:
  • Retention and stability
  • Aesthetics
  • Phonation
  • Mastication
• Components:
  • Dental component (replacement teeth, alveolar portion)
  • Obturator bulb/bung - fills the defect cavity
  • Soft silicone bung engages undercuts in the defect for retention

5. Construction and Components of the Definitive Obturator

Materials

• Acrylic resin (PMMA): most common; lightweight
• Metal framework (Co-Cr alloy): improves rigidity, clasp retention
• Soft silicone obturator bung: engages defect undercuts, provides retention and sealing

Retention Methods

1. Dental clasps on remaining teeth (most reliable when dentate)
2. Circum-zygomatic loops: surgical wire loops around zygomatic arch placed at surgery
3. Defect undercuts: soft silicone bung engages them
4. Osseointegrated implants: the gold standard for edentulous or large-defect patients
   • Zygomatic implants for extensive defects (Figure 31.10, Scott-Brown's)
   • Splinted with a retentive bar; dramatically reduces need for deep defect engagement
5. Adhesives (for facial prostheses, less used for intraoral obturators)

Multi-Part Obturators (for patients with trismus)

• Trismus (especially post-radiotherapy) prevents single-piece insertion
• Two-part design: obturator component + dental prosthesis component assembled intraorally
• Magnet linkage or other attachments connect the parts
• Multi-part impressions required in such patients

6. Surgical Modifications to Facilitate Obturator

• Bone cuts through edentulous area or extraction sockets (preserves abutment teeth)
• Lateral incisions through palatal mucosa to create keratinized mucosal flap
• Residual cavity shaped to allow undercut engagement
• Smooth sharp bony margins; use split-skin grafts within the orbit (if exenterated)
• Preservation of nasal bones in rhinectomy (supports prosthesis and spectacles)
• Reduce nasal septal projection to allow space for implant frameworks

7. Osseointegrated Implants (Advanced Rehabilitation)

• Zygomatic implants achieve high primary stability; can be loaded early
• Placed at time of primary resection (especially if post-op radiotherapy planned)
• Splinted with a bar to support obturator
• Implants allow the prosthesis to be minimally invasive (less bulky bulb needed)
• Low overall utilization rate in head-neck cancer patients; requires careful selection

8. Outcomes and HRQoL

• Obturator prosthesis is a highly positive, non-invasive approach to improve quality of life
• For limited defects (Level I-II), HRQoL outcomes comparable to free-flap reconstruction
• Large complex resections (palate + maxilla + sinuses + orbit): microvascular reconstruction gives arguably better HRQoL
• Edentulous obturated patients have worse outcomes than dentate patients
• Adjuvant radiotherapy worsens mouth opening, oral function, and swallowing outcomes
• Recent systematic review (König et al., 2025, PMID 38151428): direct comparison of surgical vs prosthetic rehabilitation shows mixed results; patient selection determines benefit

9. Facial Prostheses (Midfacial / Orbital)

• Silicone-based prostheses replace nose, orbit, external ear
• Retention:
  • Skin adhesives (older; causes irritation, displacement)
  • Mechanical undercuts + spectacle frames
  • Osseointegrated craniofacial implants (current standard) - last 30 years shift
• Pre-prosthetic surgical preparation:
  • Remove unsupported tissue
  • Smooth bony margins
  • Minimize bulk of vascularized flaps
  • Split-skin graft within orbit (stable, dry, hair-free surface)
  • Preserve nasal bones to support prosthesis vertically

10. Summary Table for Exam

Key Points to Mention for 10 Marks

1. Definition and purpose of obturation
2. Brown's classification of defect (guides prosthesis vs reconstruction)
3. Multidisciplinary team (MDT) - prosthodontist + surgeon
4. Pre-operative assessment and planning
5. Three stages - surgical/immediate, interim/transitional, definitive
6. Materials: acrylic, metal framework, soft silicone bulb
7. Retention methods: clasps, implants, zygomatic implants, multi-part + magnets
8. Surgical modifications to facilitate obturator
9. Trismus as a complication - multi-part obturator solution
10. HRQoL outcomes; role vs free flap reconstruction