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Retention of maxillofacial prostheses

Retention of maxillofacial prostheses. : By Naim Egbaria Yasser Alotaibi Majd Abo Aladas Zain Baharon Ammer Shlol. Introduction.

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Retention of maxillofacial prostheses

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  1. Retention of maxillofacial prostheses : By NaimEgbaria Yasser Alotaibi MajdAboAladas ZainBaharon AmmerShlol

  2. Introduction • The face is the most sensitive part of the body and many patients suffering from facial tissue defects because of this plays active role in social life , by facial prostheses we can restored normal life to the patients and this have been retained by various method through the years from simple glue to modern day implant , different methods of retention are used and this depend on various factor (clinical factors , patient compliance factors) to give the patient the most compatible method of retention for his prosthesis .

  3. Types of retention • Adhesive • Implant • Magnetic • Obturator • Spectacle frames

  4. adhesive • Adhesive are the most commonly used method in retention . • Its are easily available and provide sufficient retention for limited period of time , some patients have irritation duo the constant application of adhesive , its susceptible to accumulation of dust particles at the interface of the skin and prostheses .

  5. The material used in adhesive • acrylic resin adhesive • silicon adhesive • Pressure sensitive tapes

  6. Implants • Various types of dental implants are available, including : • Endosteal implants are placed in the jawbone. Typically shaped like small screws, cylinders or plates, they are the most commonly used type of implant. • Subperiosteal implants are placed under the gum but on, or above, the jawbone. This type of implant may be used in patients who have a shallow jawbone and cannot or do not want to undergo a procedure to rebuild it. • Currently only the endosteal implants are used in both intraoral & extraoral sites ,and he it’s the best retention method if have the ideal conditions • Intraoral prosthesis use with edentulous patients (minimum 2 implant should be placed)

  7. Implants • Extraoral (craniofacial implants) its used to fabrication large prostheses that rest on movable tissue . • Used of implants for retaining prosthesis depends on a number of factors such as presence of bone, , soft tissue conditions, prognosis of health for the patient, radiation therapy and economic conditions.

  8. Example of implant system : • Bar and clip retention system . • Magnets . • Mushroom and ball retention .

  9. Magnets • In dentistry both attractive and repulsive properties of magnet are used . • Magnetic repulsion has been used to limit the displacement of dentures . • attractive forces of paired magnets were used as retentive aid for sectional dentures .

  10. CLASSIFICATION OF MAGNETS : • BASED ON ALLOY USED : Cobalt containing Non cobalt containing . • BASED ON ABILITY TO RETAIN MAGNETIC PROPERTIES : Soft (easy to magnetize or demagnetize) Hard (retain magnetism permanently). • BASED ON ARRANGEMENT OF THE POLES : Reversed pole Non reversed pole . • BASED ON TYPE OF MAGNETIC FIELD : • Open field • Closed field

  11. ADVANTAGES : • Magnets provide both retention and stability . • Enables automatic reseating of the denture if dislodged during chewing. • They do not directly induce stress to root abutments. • DISADVANTAGES : • The main problem associated with the use of magnets as retentive devices is corrosion. • Wear presents in the form of deep scratches and gouges on the surface. caused by wear debris and other particles that become trapped between the magnet and the root. Finally there will be loss of retention provided by the attachment.

  12. Obturator • The support for a maxillary obturator can be maximized by appropriate treatment planning. • The results in a functional obturator that will restore occlusal function, provide acceptable speech and a pleasing cosmetic appearance to the patient .

  13. Support can be achieved by : • Support from the defect : If one side of the maxillary arch is lost completely, the prosthesis will rotate into the defect unless support is provided within the defect itself. Although this rotation is especially evident in the edentulous patients, it is also present in the partially edentulous patients and tends to place excess stress on the abutment teeth through the retentive clasps. Although the framework design will vary according to the size of the resection, the design objectives remain the same i.e. to distribute or control the functional forces so that each supporting or retaining element could be used to maximum effectiveness without being stressed beyond its physiological limits .

  14. Support from the Remaining oral structures : Support can best be provided by natural teeth in the form of occlusal, cingulum or incisal rests to resist tissue movement of the prosthesis or by partial or complete denture . The load and stress distribution is along the long axis of the abutment tooth/teeth . Sometimes natural teeth which are unlikely to withstand occlusal stresses for extended periods, might be treated by fixed splinting to more stable teeth. Precision attachments, clasps and implants can also provide support .

  15. The pre-surgical treatment planning is of great importance not only for the patient but also for the success of the surgical procedure and prosthesis. • During prosthodontic rehabilitation the support can be gained from within the defect and remaining structures. • Retention can be achieved from the non-resected tissue, scars and bony undercuts by conventional and unconventional means.

  16. Spectacle frames • These are used as an adjunct with a prosthesis to support it .They are mainly used in cases of orbital and nasal prostheses .The prostheses are attached on the spectacle frames in such a way that they attain correct position and seat in the desired position once the spectacles are worn .

  17. Advantages : The borders of the prosthesis may be camouflaged by the borders of the spectacles .This avoids the attention of the onlooker onto the prosthesis. This results in an increase in the confidence of the patient. The prosthesis is attached to the spectacle which is easier to handle in patients with low manual dexterity. Disadvantages : Spectacle frames have to be worn by patients who are not used to them. In some cases, the patient may find it bulky and difficult to adjust to. It is difficult to use it in patients with extensive facial defects involving the nose and ear .

  18. THANK YOU for your attention

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