nasal and midface

NASAL & MID FACE DEFECTS

Facial defects can result from:
1-Truma. 2-Treatment of neoplasm. 3-Congenital malformation.

Rehabilitation of facial defects

Surgical reconstruction verses prosthetic restoration: It depends on : 1-the size of the defect. 2-the etiology of the defect. 3-the age of the patient.

Nasal defects

Before and after surgical reconstruction

Before &after surgical reconstruction

Main problems of nasal prosthesis
1-Retention of large nasal restoration. 2-Esthetic of the prosthesis. 3-Color matching. There are internsic & externsic coloration. The internsic coloration are more stable while extrinsic coloration wear rapidly because of ultraviolet rays & surface oxidation.


Impressions
Prior to surgery ,facial impressions are preferred because they provide useful information for clinician. Steps: 1-The pt is in upright position. 2-Elastic impression materials is used as Irreversible hydrocolloid. 3-The nasal passage should be blocked out with gauze.

Impressions

Prosthodontist prefer irreversible hydrocolloid because it has low tear strength & high flow. Facial impression is carried out for the pt.

Steps of impressions

4-Using the preliminary cast ,master impression tray is fabricated confined to the defect area. 5-A syringe is used to inject impression material to areas of difficult access. 6-Taking care not to compress the tissue bed. 6-After setting of the impression, a master cast of dental stone is prepared.

Impressions

Sometimes plaster impression is used in conjunction with alginate in these cases a piece of gauze put inside the alginate impressions while the impression is still soft to provide retention for the plaster.

Steps of impressions

Steps of impressions



Steps of impressions

Types of nasal prosthesis

1-Temporary nasal prosthesis. 2- Definitive nasal prosthesis.

Temporary nasal prosthesis

-Approximately 3-4 weeks following surgery. -Heat polymerizing methyl methacrylate is preferred because it can be relined with a temporary denture reliner. -Retention of the prosthesis is accomplished with medical grade skin adhesive.

Definitive nasal prosthesis

-After 3-4 months fabrication of definitive prosthesis is carried out. -Flate defects in which the nasolabial folds remain are the easiest to restore prosthetically. -In most pts the residual tissue bed is highly mobile therefore prosthesis of highly flexible materials are advised.

Classification of nasal restoration

It can be classified according to the means of retention into: 1-Adhesives: medical grade adhesive Disadvantages : a- Applied periodically. b- sometimes allergic. c- difficult to clean the skin & prosthesis.

Classification

2- Eye glass frame. 3- Implant : Bone in and around facial defects into which osseointegrated fixtures can be placed depends on the size, location of the defect and integrity of the residual structures.


Sculpting
-If a facial cast has been fabricated prior to surgery, a wax duplicate of the nasal portion is adapted to the cast of the defect. -If presurgical casts are not available a mass of clay or wax is adapted to the cast of the defect & basic contours are completed. -Eyeglass frames should be worn to improve the shape of the prosthesis.

Processing & delivery

-The wax pattern is invested in the mold material. -Two-piece molds are adequate. -The inner surface of the prosthesis is hollowed to reduce weight & is then delivered. -Retention is achieved with medical grade skin adhesives.

Before & after prosthetic restoration

Before & after prostheticrestoration

Mid face defects

Restoration of large mid face defects
Advanced tumors of the midfacial region resulting in surgical defect which may involve loss of both extraoral & intraoral structures, including portions of the nose, upper lip, cheek, and orbital contents. Also segement of the maxilla, mandible, associated soft tissue, and teeth may be involved.



Complications
Loss of integrity of the oral cavity results in difficulty in mastication, swallowing, control of saliva, and speech production. These functional disabilities combined with cosmetic disfigurement which lead to sever psychological impact on the pt

Prosthetic prognosis

It depends on: 1- The size & location of the surgical defect. 2-Movable tissue bed may complicate the function of the prosthesis & compromise its retention. 3-The status of lower lip function is another prognostic indicator. 4-The adaptability of the pt.


When surgical reconstruction is not possible slight modifications may be useful to the prosthodontist as:
1-Retention of the teeth that can be used to support & retain the prosthesis. 2-Preparation of the soft tissue bed that will create undercut areas for retention. 3-Placement of skin grafts to minimize tissue contraction.

Types of facial prosthesis

1-Temporary midfacial prosthesis. (can be delivered 10 days after surgery). 2-Definitive mid facial prosthesis. Modeling plastic & thermoplastic waxes can be used to record the movement of the tissue. After the tray is border molded, the impression is completed with elastic impression material.

One-piece or two piece restoration

Two-piece restorations have advantage that the forces & movement generated into the oral portion by swallowing & mastication not transferred to the facial portion. Two-piece restoration is used to engage undercuts that cannot be engaged otherwise ( change path of insertion).

Most pts preferred one-piece restoration due to:

1-Food impaction in & around the interface of two piece restoration. 2-Two-piece prosthesis are more difficult to control and manipulate than one piece restorations. Retention of the facial prosthesis is accomplished by straps, adhesives, tape, eyeglass frames, engaging usable undercuts, teeth, or combination of these methods.



Placement of extraoral implants
1- It can be placed in frontal bone area. 2-Zygomatic arches. 3-Maxillary tuberosity. 4-Premaxilla.

Before & after prosthetic restoration

The end