Facial Implant And Implant-Retained Craniofacial Prostheses

Dr Pallawi Sinha

CONTENTS

1. Introduction

2. Advantages of Maxillofacial implants over conventional adhesives.

3. Patient assessment and selection

4. Treatment planning.

5. Surgical technique for placement of Maxillofacial implants.

6. Auricular prosthesis.

7. Ocular prosthesis.

8. Nasal prosthesis.

9. Midfacial prosthesis.

.

10.skin response at abutment site

11.Follow up and management

12.Review of literature.

13.References

Prosthesis with osseointegrated implants and quality of life. J Craniofac Surg. 2010 Jan, Vol. 21, No. 1, pp. 94-6.

• The use of facial prostheses such as wax ears has been reported in ancient Egypt.

• The first historically documented evidence comes from sixteenth century, when the French surgeon Ambroise Pare describes the first nose prostheses from gold, silver which were held to the face by a string tied around the head.

• In late 19th century Claude Martin conceived an idea of an immediate prosthesis using tissue excised from the maxilla and mandible as a template for fabricating complex appliances.

• In 20th century, while the quality of lifelike craniofacial prostheses was improved with introducing of silicone materials, the problem of their retention, which is important for aesthetics, function, and comfort, was not entirely solved.

Prosthesis with osseointegrated implants and quality of life.

J Craniofac Surg. 2010 Jan, Vol. 21, No. 1, pp. 94-6.

• With increasing aesthetic requirements conventional fixation tools such as skin adhesives, skin pockets,

skin loops, and glasses became unsuitable.

• It was Branemark, who first placed a modified extraoral implant for a bone- anchored hearing aid in 1977 and a bone-anchored auricular prosthesis in 1979.

• These events changed the concepts of prosthetic maxillofacial reconstruction.

• Since then, osseointegrated extraoral implants are widely used for retention of orbital, ear, and nose prostheses.

• The implants had a dramatic impact on patient acceptance of facial prostheses.

• Patients like the security, comfort, and convenience of implant-retained prostheses.

• These benefits that are not attainable with earlier methods of retention.

• Maintenance of fine feathered margins and simple positioning of an implant-retained craniofacial prosthesis greatly increased their aesthetic qualities

• Methods of retention of craniofacial prostheses

The anchorage of prostheses can be achieved in four ways :

1) anatomical anchorage : Already existing anatomical structures such as undercut areas in the cavities of an orbital defect

2)mechanical anchorage : spectacle frames

3) chemical anchorage : using adhesives

4) surgical anchorage : using surgically created retention elements

Advantage of Maxillofacial implants over conventional adhesives

• Improved retention and stability of prosthesis.

• Elimination of occasional skin reactions to adhesives.

• Ease and enhanced accuracy of prosthesis placement.

• Improved skin hygiene and patient comfort.

• Decreased daily maintenance associated with removal and

reapplication of adhesives.

• Increased longevity of prosthesis.

• Enhanced aesthetics at the lines of junction between the

prosthesis and skin.

Facial trauma: general principles of management.

J Craniofac Surg. 2010 Jul; Vol.21, No. 4, pp. 1051-3.

• Acquired facial defects, especially after radical surgical operations result in huge functional, cosmetic and psychological handicap in patients.

• For large defects ,two paths can be followed, those of either

1)plastic surgery 2)prosthetic rehabilitation.

.

• The procedures involved in plastic surgery are extremely suitable for the correction of less complex aesthetic units or partial defects of the ear, nose and orbital cavity.

• Particularly mobile areas such as the lips are difficult to be adequately treated with prostheses and should definitely surgically reconstructed, even if the remaining defect is treated with a prosthesis.

• Plastic surgical reconstruction of these defects is frequently limited due to unfavorable conditions, such as vascular compromise of the surgical bed due to radiotherapy, insufficient residual soft and hard tissues.

Facial trauma: general principles of management.

J Craniofac Surg. 2010 Jul; Vol.21, No. 4, pp. 1051-3.

• The choice between surgical reconstruction and prosthetic restoration of large facial defects remains a difficult one and depends on the size and etiology of the defect, as well as on the wishes of the patient.

Facial trauma: general principles of management. J Craniofac Surg. 2010 Jul; Vol.21, No. 4, pp. 1051-3.

• For large defects, a multidisciplinary approach is recommended, combining flap reconstruction and implant-retained prosthetic rehabilitation to achieve optimal results.

• Facial prostheses are constructed by maxillofacial surgeon, implantologists, prosthodonticts and technician, as an alternative treatment when facial defects cannot be surgically fulfilled.

• Development and application of osseointegrated implants to facial defects has changed patient perceptions of facial prosthetics.

• Implants allow convenient and secure positioning of the prosthesis, leading to greater patient acceptance.

• Ball attachments, bars or magnetic abutments are a method of choice in replacement of missing hard and soft facial tissues.

In contrast to intra-oral implants, which are available in a wide range of shapes and with different surface preparations, craniofacial extra oral implants are far less diverse .

The most widely used is the Branemark extra-oral craniofacial implant system. These implants are shorter than the intraoral implants and have a perforated flange.

Maxillofacial implant fixtures

are fabricated from pure

titanium. They are available in

either 3 mm or 4 mm lengths

and with a 5-6 mm diameter

flange. The flange facilitates

initial stabilization of the

implant and prevents undue

penetration into interior

compartments.

• Bone stock in temporal, orbital and midfacial regions is not often adequate for the placement of implant so it is a predominant limiting factor.

• To compensate for this, extra oral implants are short, 3-6 mm in length .

• It has been claimed that this flange increases the implant surface area in contact with bone, facilitates initial immobilization and prevents undue penetration of the implant intracranially.

• Perforations in the flange are supposed to add additional surface area and provide mechanical stabilization

Exposure of the perforated flange creates a protected environment for accumulation of debris and microbial colonization with ensuing infection, which can be difficult to control.

• Other component are similar to intraoral implant but differ in size.

Healing abutmentCover screw

abutment driver Hex tool

Hex tool and abutment driver are used to tighten the cover screw and healing abutment respectively.

Extraoral implant systems 1)solitary Implants

2) Grouped Implants

1)solitary Implants• Branemark system • ITI systems

Grouped Implants: grid and plate systems

which are secured with several smaller bone screws.

With these systems an implant can also bear several

percutaneous abutments

Other systems with solitary implants

• IMZ system: marketed by Friatec (Friadent),• Dentsply Friadent: is currently marketing the

Ankylos system. • Southern Implants : is marketing extraoral

titanium screws

Extraoral systems with solitary implants

• Branemark system • The Branemark system was the first implant system to

be used extraorally . The longest and most extensive experience has been gathered with this system .

• For the extraoral area, titanium screws of a length of 3 and 4 mm (and 5.5 mm) are available.

• The flange was originally designed to avoid an intracranial dislocation of the implant due to trauma. The flange is now available in closed form. At present flangeless screws are also available .

• Abutments can be held by a special clamp. • Currently the Branemark system is being marketed by the

Cochlear Company under the brand name Vistafix.

2 )ITI systems • With ITI implants (International Team for Implantology)

marketed by the Straumann company, a sand-blasted, large grit, acid-etched surface was introduced, the so-called SLA surface.

• The resulting roughness is two-staged: the greater roughness of 20 µm is overlaid by a finer roughness of 2 µm intervals .

Grouped Implants Epitec system Epiplating system Both Epitec system Epiplating system used subperiosteally, but fixed with bone screws.

Epitec system• The Epitec system, developed in 1991 by Mustafa Farmand and

the company Leibinger, represents a great advancement. • The system consists of a mouldable quadratic titanium grid with

16 thread holes, the so-called 3D carrier plate, and self-tapping 2 mm titanium screws which are available in lengths of 4.5 and 6 mm.

• The 3D carrier plate has to be cut to the required shape.

• Single extensions are not stable. Plate retention results primarily from the use of these monocortical bone screws.

• Due to the flexibility constructions extending into the defect are currently no longer recommended.

Epiplating system • The Epiplating system was developed in 2000 by the

Medicon company.

• It is the adaptation of the 2.0 titanium mini-plate system produced by Medicon and used in traumatology.

• Specially adapted implants are available for the auricular, orbital and nasal regions, as well as a universal plate.

• The titanium plates of the Epiplating system are 2 mm thick, 2 mm in width and are thus stronger than the Epitec grid system.

• The thickness of the plate is 2 mm, appropriate for 4 thread turns, which counterbalances any tendency of loosening of the percutaneous base posts or magnets.

Coupling between abutment and prosthesis Metal bar Magnetic connections

• Typically, a metal bar is screwed onto the percutaneous posts onto which the prosthesis can then be clipped

advantage • retention strength can be individually adjusted and

altered by bending the clips.

• The bar construction, however, requires substantially parallel aligned percutaneous posts so that the least possible strain occurs.

• This parallelism of the posts is never achieved in the orbital area, and not always in the mastoid.

Magnetic connections:

• The advancement in magnetic connections represents huge progress.

• They facilitate the cleaning and insertion of the prosthesis by the patient. For this reason in the nasal and orbital areas magnets are used almost exclusively today.

Patient assessment and selection• Maxillofacial reconstruction based on the principles of

osseointegration is always an elective procedure.

• Many factors and variables need to be considered carefully, including age, the presence of any disease progress, the significance of any previous therapy, alternative available treatments and the patient's own wishes.

Adrenal disorders:• Patients with a history of adrenal gland disease, whether

hyper functioning or hypo functioning, face similar problems related to dentistry and stress.

• The body is unable to produce increased levels of steroids during stressful situations and cardiovascular collapse may occur.

• Recent Myocardial Infarction (MI):

• If surgery is done within 3 months of MI, the risk of another MI is 30%.

• If within 3 – 6 months, it is 15%. • After 12 months the incidence of recurrent MI stabilizes

at about 5%.

• Osteoporosis:The bone density affects the treatment plan, surgical approach, length of healing and the nature of loading.

Fibrous Dysplasia:• A disorder in which fibrous connective tissue replaces

areas of normal bone.

• It is found twice more commonly in women than men and may affect a single bone or multiple bones, twice more commonly in the maxilla than mandible.

• Implant dentistry is contraindicated in the regions of this disorder

• Paget’s disease:

• A slowly progressive chronic bone disorder where both osteoblasts and osteoclasts are involved, but osteoblastic activity is more predominant.

• The maxilla is more often involved than the mandible. Implants are contraindicated in the regions affected by this disorder

• Radiation therapy:

• Disruption of defense mechanisms, compromised Endoosseous vascular system, and localized loss of osseous vitality are the main insults to the tissues while the patient undergoes radiation therapy.

• With regard to bone, the osteogenic potential of the periosteum is most severely affected.

• All these conditions can severely limit the prognosis for reconstructive procedures.

Such patients may be subjected to osteoradionecrosis and should be treated with caution only after the dentist consults the radiotherapist

Ocular prosthesis

The loss or absence of an eye may be caused by a

Congenital Defect, Trauma, Tumor A Painful Blind Eye Sympathetic Ophthalmia,

or the need for histological confirmation of a suspected diagnosis

Eye tumors are manifested by a number of symptoms: dystopia,

bulbar motility dysfunction, exophthalmia,

and diplopia.

Depending on the severity of the situation, the surgical management may include one of 3 approaches: evisceration, enucleation, or exenteration. • Evisceration : is a surgical procedure where the

intraocular contents of the globe are removed, leaving the sclera, Tenon's capsule, conjunctiva, extraocular muscles, and optic nerve undisturbed ,the cornea may be retained or excised.

• Enucleation is the surgical removal of the globe and a portion of the optic nerve from the orbit.

• Orbital exenteration :is the en bloc removal of the entire orbit, usually involving partial or total removal of the eyelids, and is primarily performed in order to eradicate a malignant orbital tumor.

• Loss of an eye can cause significant physical and emotional problems. Replacement of the lost eye as soon as possible after healing is to promote physical and psychological healing for the patient and to improve social acceptance.

• Prosthetic rehabilitation that restores these facial deformity may improve the level of function and self-esteem for patients.

Total exenteration allows adequate spacing for proper positioning of a prosthesis. A subtotal exenteration or a partially filled orbit restricts the facial prosthesis to being thin, with a less natural appearance.

Because the orbital walls are thin, only the superior, lateral, and inferior orbital rims are suitable for osseointegration of titanium implants

Surgical Procedure :

The osseointegration procedure is performed in two stages.

In the first stage the titanium implants are placed into the orbital rim and the implants are allowed to bond to bone through osseointegration.

The second stage is performed 3 to 4 months later when tissue penetrating abutments are attached to the initial implants

craniofacial osseointegrated implant -int j oral maxillofacial Implants 1997;12;200-10

craniofacial osseointegrated implant -int j oral maxillofacial Implants 1997;12;200-10

Stage 1 It can be performed under general or local anesthesia. A skin incision is marked with a marking pen along the

orbital rim at the designated locations. The skin incision is made just anterior to the rim, and a

flap of skin, muscle, and periosteum is elevated to expose the bony rim.

• The initial drilling is done with an exploring cutting bur, which produces a small hole.

• The orientation of this hole should be directed toward the center of the orbit. This allows space for any future prosthesis.

• If the bone is adequate, a 3 - 4 mm spiral drill with a countersink is used to form the final hole diameter

• Next, the threading of the hole is done with the threading tap.

• This step is accomplished at the slow speed of 8 to15 rpm that allows the precise cutting of bone needed for proper implant setting

.

• The titanium implant is selected for the hole depth (3 or 4 mm) and screwed into the threaded hole with an implant mount on the drill

• The implant has a cover screw placed that is screwed

into the internal threads of the implant.

• .

• A topical antibiotic is applied with a pressure dressing. This dressing is removed in 1 week.

• If the continuity of the orbital rim is disrupted, several options are available for bony reconstruction to create a bed for implant placement. Common sites for autogenous bone grafts are the calvarial bone, iliac crest, and fibula

Stage 2 : This is done after 3 to 4 months. The second stage involves the placement of Titanium abutments

and the proper thinning of the skin around them to prevent the movement of skin adjacent to it.

This step prevents skin irritation and infection and allows integration of the skin with the abutment. It is usually done under local anesthesia

A trephine is used to cut an opening over the implant. An abutment is placed through the opening and attached to the implant with an internal screw. The abutment can be 3 or 4 mm in height. The abutment is covered with a healing cap. Antibiotic soaked gauze is wrapped around the abutment to immobilize the skin.

Four to five weeks after stage 2, the patient is ready for prosthesis fitting

• A multiple tray technique for implant-retained orbital prostheses.(J PROSTHET DENT 1995;73:158-61.)

Making an impression of the orbital area, with accurate transfer of the implants, can be a difficult procedure. • A method of making an accurate transfer impression for

an implant orbital prosthesis was described.A four-component tray technique is described.

proper reproduction of all soft and hard tissue detail and the position of the implants.

• A multiple tray technique for implant-retained orbital prostheses.(J PROSTHET DENT 1995;73:158-61.)

• After exposure of the implants and placement of healing cuffs, make an irreversible hydrocolloid impression of the defect .

Acrylic resin custom trays on preliminary model

• Pour the impression in dental stone.• On the primary cast, place approximately 5 mm of relief

wax over the duplicated implant healing cuffs to allow adequate space for impression material.

• separating medium

Fabricate the acrylic resin custom trays. Make two trays triangular in shape and separated from each other to separate the defect into superior and inferior parts. Make a third middle tray over the other trays in position on the cast.

Make the external matrix (fourth) tray by lubricatingthe external surfaces of the three internal trays on the preliminary cast and form the matrix over the internal trays.

When set, remove the external matrix tray and perforate it with round bur to enhance mechanical retention of the impression material.

• Remove and polish the trays.• Place appropriate abutments on implants.• Try the fit of the trays and assess for adaptation to the defect.• Lightly lubricate the hair in the region with a petroleum based

lubricant.• Place the implant transfer components in position.

Again assess the trays for unobtrusive fit over the implant components.

Paint the trays with the proper adhesive and allow to dry. Make the inferior impression by syringing impressionmaterial around the implant transfer parts, in the inferiorpart of the orbit, and in the tray. Gently seat the tray into place and remove the excess material.

• Lightly lubricate the external aspect of the inferior impression with petroleum jelly.

Make the superior impression in the same manner.If a middle tray is used, check the clearance for the tray.• Adjust the tray and make an impression with sufficient

impression material to allow joining of all impressions without locking one tray to the other.

Adapt the external matrix tray over the impressions to assess fit; then paint with adhesive and allow to dry. With impression material at each end, gently seat the external matrix tray over the impression trays and allowed to set.

Disassemble the impressions in reverse order.Place the appropriate implant transfer analogs in the impressions

Reassemble the impressions and use sticky wax to secure them together .Box and pour the impression in dental stone

This technique provides for a vertical path of removal for the implant transfer copings in the superior and inferior borders of the orbit

• The advantages of this method are accuracy and removal of impressions on implants that are placed in opposing positions in a limited space, which prevents the removal of a one-piece impression.

An impression technique for implant retained orbital prostheses. J Prosthet Dent 2008;100:52-55)

• This article describes an impression technique for an implant-retained orbital prosthesis;

• implant impressions in the conventional manner was not possible due to improper implant positioning.

This article describes an impression technique for transferring the implant position to the definitive cast when the position of implants prevents the use of impression copings.

• An impression technique for implant retained orbital prostheses. J Prosthet Dent 2008;100:52-55)

1. Pack moist gauze, into the orbital defect, and place the magnets on the center of the magnetic abutments .

Make an impression of the magnets, abutments, and defect area using irreversible hydrocolloid impression material.Box and pour the impression with dental stone.

• To provide clearance from the underlying skin, place 1 layer of baseplate wax onto the surface of the cast. Trim the wax neatly around the replica cast of the magnets.

• Apply a coat of separator to the cast.

Mix the autopolymerising acrylic and place it on the cast, bridging the spaces between the adjacent replica of the magnets.• Allow the acrylic resin to polymerize and remove the

substructure from the cast. Trim the excess acrylic resin with a carbide bur.

• For optimal results, allow the resin substructure to polymerize for 24 hours.

• Remove the magnets and wind polytetrafluoroethylene (PTFE) tape around the abutments.

• Place the tape around the abutments to block out the undercuts. Replace the magnets.

Polytetrafluoroethylene tape around magnetic abutments to protect acrylic resin-to-skin contact

• Place the substructure on the magnets and verify adaptation. Trim the acrylic resin as needed to ensure fit.

Verifying adaptation of substructure to magnets.

• Lute the substructure to the magnets with autopolymerising acrylic resin .

• Allow the applied acrylic resin to polymerize. • Remove the substructure that now incorporates the

magnets. Remove the polytetrafluoroethylene (PTFE )tape. • Trim the excess acrylic resin with a carbide bur.

• Pack moist gauze into the orbital defect. Lubricate the skin and eyebrow with petroleum jelly .Place the acrylic resin substructure onto the magnetic abutments. Place light-body vinyl polysiloxane impression material under the acrylic resin and over the tissue site with a syringe, working outward from the abutments

• Gently apply the tip of the syringe close to the skin, and move it back and forth in a small semicircular motion from the area covered with impression material into the uncovered area to minimize the trapping of air bubbles in the impression

Apply adhesive over the vinyl polysiloxane and allow it to dry. Mix the autopolymerizing acrylic tray resin.

Place a thin layer of resin over the impression. Apply a continuous stream of compressed air with water spray during the exothermic phase of polymerization.

• Remove the impression with the incorporated substructure from the defect site.

• Connect the implant analogues to the magnets• Box and pour the impression in dental stone .• Allow the stone to set. Recover the cast and acrylic resin

substructure for use .

• Fabricate the orbital prosthesis from silicone.

• The advantage of this technique is that the transfer of the spatial relationships of the implants from the defect to the definitive cast is ensured without using impression copings.

• A disadvantage of the procedure is the requirement of an additional appointment to make the definitive impression.

• An ocular prosthesis can be either readymade (stock) or custom-made.

• Stock prosthesis comes in standard sizes, shapes, and colors. They can be used for interim or postoperative purposes.

• Custom eyes have several advantages including better mobility, even distribution of pressure due to equal movement thereby reducing the incidence of ulceration, improved fit, comfort, and adaptation, improved facial contours, and enhanced esthetics gained from the control over the size of the iris, pupil, and color of the iris and sclera.

• Surgical and Prosthetic Considerations to Rehabilitate an Ocular Defect Using Extraoral Implants: A Clinical Report

Journal of Prosthodontics 21(2012) 205–208• This clinical report shows the use of extraoral implants

to rehabilitate an ocular defect.

• The patient, a 57-year-old man had squamous cell carcinoma that is completely resected.

• After surgery, the peri-orbital region was kept intact..

• A custom-made artificial acrylic resin eye was selected according to the color, contour, and size of the patient’s healthy left eye.

• Over the stone cast, a layer of warm wax was placed on the defect area.

• This wax sheet was tried on the patient’s face to serve as the basis for correctly positioning the artificial eye, based on referential face lines .

• This was an important procedure, because inadequate eye positioning frequently leads to a poor esthetic result.

• the remaining tissues surrounding the artificial eye were carved in wax, observing the anatomic details of the left side, especially the upper and lower eyelids.

• A natural and esthetic wax-up was completed.

Surgical template based on the diagnostic wax-up.

Prosthesis margin reference lines to guide correct implant placement.

Titanium cylinder dental implants placed in the zygomatic bone. The healing abutments were installed at the same time.• A reduction in skin thickness and a compressive suture

were performed in the one-stage implant surgery

• A framework pattern was planned after verifying there was adequate space for the skin (1 mm) and the external contour.

Initial clip bar framework design.

The patient experienced a great deal of difficulty in maintaining a clean defect area after casting procedures and the use of this framework for a week

The framework of the metal structure was designed with a volume too large to hold an orbital prosthesis.

• Therefore, another framework design was planned with a retention method consisting of two cylinder magnets positioned on a bar segment .

• After final casting procedures, the magnet cap bases were fixed on an acrylic base behind the iris

and the prosthesis silicone pattern was invested and processed in an RTV platinum silicone elastomer

Frontal aspect of the silicone prosthesis.

Lateral aspect of the silicone prosthesis.

Auricular prosthesis

Extraoral applications of osseointegrated implants. J Oral Maxillofac Surg. 1991;49:33–45

• The indications for autogenous auricular reconstruction versus prosthetic reconstruction with osseointegrated implant-retained prostheses were outlined in Plastic and Reconstructive Surgery in 1994.

• The choice between the two remaining techniques, autogenously reconstruction and prosthetic reconstruction, depends more on the surgeon’s training and tradition than on an analysis of which procedure is preferable in a given clinical situation.

• For example, most children with microtia in the United States are treated with autogenous techniques.In contrast, the same deformities in Sweden are more commonly treated with prosthetics.

• The etiology of the loss of an auricle can be either acquired or congenital.

• Among acquired cases, gun shot injuries, traffic accidents ,burns, ablative cancer surgeries are the reasons.

• Patients with post traumatic or post ablative auricular defects are more often in adults, and their defects differ from those of children with congenital deformities in several ways.

1) The skin loss and scarring resulting from trauma or previous surgery may make standard autogenous reconstruction difficult.

2) The tragus is frequently preserved in the trauma/ablative patient, making the aesthetics of prosthetic reconstruction much more favorable.

• The presence of a tragus allows the anterior border of the prosthesis to be hidden, a major aesthetic benefit.

• The diagnostic step is an important point that must be clearly defined in construction of an auricular prosthesis.

• CT of the temporal bone and clinical photographs of the patient should be obtained preoperatively to plan the placement and appropriate size of the implants .

• To evaluate the thickness and spaces of mastoid cortical bone in order to preserve the duramater.

The axial CT scan of the cranium. the distances from the masoid region to the adjacent anatomical structures such as external auditory canal, duramater and the orbit.

• It has been suggested that the mastoid region as a recipient site could offer the best results in implant retained auricular prosthesis.

• Wright et al have stated that, the mastoid region provided a high degree of predictable individual

implant survival.

• auricular implants enhance retention and stability of prostheses, improving the patient’s confidence and sense of security.

• In addition, attachment systems aid in the proper positioning of prostheses, facilitating insertion by the individuals with auricular defects.

• The implants should be placed at least 20 mm away from the external acustic meatus and 15 mm from each other.

• In addition, in cases with two implants, 9 and 11 o’clock positions are recommended.

• Implant surgery may be performed in single or two stages.

• because the operation area get covered with a previous scar tissue formation because of compromise the vascular supply of the area, the two-stage procedure is not recommended.

One-Stage Surgical Technique for Auricular Implant Placement

• Implant Site Selection: This must be done before the patient is taken to surgery. The external ear canal is a good landmark. The ideal placement is 18 to 22 mm from the center of the external auditory meatus, and on the left-hand side it is between the 1-0’ and 2-0'clock positions for the upper cranial implant and between the 3:30 and 4:30 positions for the caudal implant.

• The reason for this is that the implants and the bar construction will be located underneath the antihelix ridge. This is important to achieve an adequate depth and contour of the prosthesis.

• Marks are made with surgical ink where the implants should be placed, and the area is cleaned and patient is draped in the usual way. The incision line, usually 7 to 10 mm behind the intended implant sites is marked. 10ml of 2 % lidocaine with epinephrine is injected, and the incision is made down to the periosteum. That flap is folded anterior and kept in place with two self-retaining retractors.

Implant Placement:

The positions of the implant sites are checked and marked in the

periosteum.

A 6 mm wide incision is made in the periosteum and the drilling

with a guide drill is started. During all drilling procedures,

generous cooling with saline solution is important.

• When the lower implant is in place, the position of the upper implant is selected. The distance between the two implants should be at least 15 to 20 mm. The position of the cranial implant often will be in the temporal bone where the bone in most cases is dense and thicker. The drilling in the cranial site is started with a 3 mm guide drill. If bone is still found in the bottom, a drill that will provide space for a 4mm implant is used

• It is important to make sure that the whole length of the guide drill has gone down. The reason is that the next drill, which is the spiral drill with a countersink edge, does not cut at the tip. The drills are made of stainless steel and 1,500 to 3,000 rpm is used. The next steps are made at slow speed, 8 to 15 rpm, and with titanium tap

The titanium tap is picked up, with the connector placed in

the low speed hand piece. The tap is kept over the

entrance and the direction is checked carefully. Adequate

cooling is used when the tap is removed.

• The implant mount is picked up with the fork shaped instrument and the screwdriver. The implant mount is screwed on top of the implant. The implant site is cleaned of soft tissue and bone fragments by flushing with saline and using a blunt dissecting instrument.

• The implant mount with the implant is picked up with the adapter on the hand piece of the drill and kept over the hole. The direction is checked with the drill at low speed, the implant is allowed to find its way into the threaded hole using slight pressure

• When the implant is all the way down, the hand piece is turned slightly counterclockwise to release the implant mount from the connector. It is Important not to tilt the implant mount when disconnecting it from the hand piece. The implant mount is then removed from the implant. It is then covered with the thin skin and sutured is placed.

Soft Tissue Management :

1) The immobility of the skin close to the implants relative to the

underlying bone and the abutment is very important. This is

achieved by making a subcutaneous tissue reduction at the

implant site.

2) There should be no hair follicles present in the skin at

the Implant site.

These two goals can be achieved by reducing the

thickness of the flap or by using a split-thickness skin

graft

Abutment Connection :

With a 4mm disposable skin punch, a hole is made immediately

over the implant and the abutment is secured to the implant

with an internal screw.

When the fit is established, the abutment screw is tightened firmly.

Healing caps are then attached to the abutments to keep

ointment soaked gauze down toward the skin to avoid

postoperative hematoma and swelling.

The surgical procedure is finished by applying a firm mastoid

dressing for 1 day. After this, only a light dressing is needed.

Postoperative Care : After 5 to 7 days, the packing and the healing caps are removed

and the surgical field is left open.

A mild antibiotic ointment is prescribed and the patient is told to use that for a week or two and then just occasionally.

Three weeks after operation the patient may start to clean the area with soap and water.

implants are left without any load for 3 months.

• The choices of retentive mechanisms to be applied on the implants depend on the patient, the number of the implants and the flexibility of the episthesis.

Locking retentive attachment for an implant-retained auricular prosthesis. J Prosthet Dent. 2002;87:336–338

The conventional retention techniques involve magnetic or clip retention provided by golden bars and ball clip or magnet retentive cap systems.

• For the use of a golden bar, at least two bone-fitting implants and a moderately hand-skilled patient are needed.

Magnets can be used with at least 3 bone- connected implants.

• In cases with three implants, a cantilever extension of the bars could be planned.

• If four bone connected implants were used, there is no need for a cantilever extension of the bars.

• Episthesis connected on bars between four implants by ball shaped caps are also used.

• An impression and cast construction technique for implant-retained auricular prostheses(J PROSTHET DENT 1996:75:45-9.)

• Implant-retained auricular prostheses provide a challenge with regard to adaptation of visible margins that may adversely influence the esthetic result of the prosthesis.

• Movement of the mandibular condyle and soft tissues associated with changes in head position can result in the loss of contact of the anterior margin of the silicone prosthesis with the underlying skin.

• The exposed anterior margin of the implant retained auricular prosthesis must maintain skin contact at all times if the esthetic value of the prosthesis is to be preserved.

• The design of the fitting surface should only allow for prosthesis-skin contact at the anterior and conchal margins and the posterior conchal margin must include an aeration channel.

• The goals of the technique are (1) to make an impression that allows continuous skin contact by the anterior silicone margin.

(2) to construct a master cast that provides adequate planned spacing under the completed prosthesis, and

(3) to construct a master cast that does not require the retentive bar to be returned to the mold for prosthesis processing.

• Make a preliminary impression that incorporates the implant impression copings.

• Fabricate the retentive bar and clip retained resin substructure

• Space the acrylic resin substructure to provide 1 to 3• mm of clearance from the skin.

• The custom tray must provide for clear visualization of the retentive bar through the resin substructure through a window in the tray

• Assess the movement of the condyle of the mandible under the preauricular skin to determine the point of maximum skin depression.

• Also assess head movement for maximum skin depression and record the impression in these positions. Mark the desired position of the prosthesis on the skin.

• The mandible can be held open in the desired position with a mouth prop.

Mark the desired position of the prosthesis on the skin.

• Load uncatalyzed silicone putty into a disposable syringe • Place the acrylic resin substructure in position on the

retentive bar and syringe the silicone putty around the margin of the acrylic resin substructure.

• Use a plastic instrument to remove the excess silicone putty.

• Paint the custom impression tray with adhesive and load the tray with polyether impression material. Select the viscosity according to skin mobility.

• Recording of impression with mouth prop holding jaw open and head in predetermined position. Confirmation of relationship between custom tray, acrylic resin substructure, and retentive bar through cut out in custom tray.

Recover the impression and mark the area of soft tissue that is not to have tissue contact anterior to the acrylic resin substructure on the impression surface.

use a photocopy (on transparent sheet) of normal ear to help demarcate anterior margin, internal spacing, and aeration channel.

• Reduce the impression surface in the marked with tungsten carbide rotary instrument.

• Assess the depth of spacing with a periodontal probe.

• To provide a define margin, trim the impression material margin around the resin substructure.

• The impression surface posterior to the resin substructure can be reduced to create the opening for the aeration chamber under the ear prosthesis.

• Bend a stainless steel wire of diameter that matches the retentive bar to replicate the bar.

• This is introduced into the clips in the resin substructure.

• Box and pour the impression.

• Incorporate the replica of the bar, soft tissue spacing, and anterior soft tissue recording for anterior margin of silicone prosthesis into the completed cast to provide an esthetic margin.

Fitting surface of two prostheses processed out ofsame mold.

Completed prosthesis shows contact of silicone margin along anterior border.

Anterior esthetic margin of prosthesis maintain skin contact during extreme mandibular movements.

• An implant-retained auricular impression technique to minimize soft tissue distortion(J Prosthet Dent 2003;89:97-101.)

Auricular defect site with indelible ink orientation lines used for positioning diagnostic wax pattern. Small circle indicates position of temporomandibular joint.

• Connect the impression copings with prefabricated acrylic resin bars .Lute the ends of the resin bars to the impression copings with acrylic pattern resin.

• The use of prefabricated acrylic resin bars will minimize the amount of error that would occur as a result of polymerization shrinkage.

• light-body vinyl polysiloxane impression material over the tissue site and impression copings.

• Apply only enough material to cover the skin with approximately 3 mm of polyvinyl siloxane

Apply a thin layer of tray adhesive over the vinylpolysiloxane and allow it to dry.

• Thin layer of tray material applied over vinyl polysiloxane impression material to provide rigidity.

• Apply a continuous stream of compressed air with occasional water spray to keep the material cool.

• The polymerization of the acrylic tray resin can create a considerable amount of exothermic heat if a thick layer of tray acrylic is applied.

• Remove the impression from the skin with a minimum amount of leverage.

• Connect abutment replicas to the impression copings and tighten the guide pins .

• Box and pour the impression in dental stone. Use just enough dental stone to cover the abutment replicas. Excess dental stone will only increase the amount of expansion and subsequent error.

• Allow the stone to set for a minimum of 45 minutes.• Recover the cast for use

Master cast with transferred indelible ink orientation lines used for positioning diagnostic wax pattern. Small circle indicates position of temporomandibular joint.

Fabricate the prosthesis, The anterior dam will help to compensate for natural postural positions and soft tissue movements associated with eating and conversing

Clinical evaluation of a newly designed single- stage craniofacial implant: a

pilot study. J Prosthet Dent. Vol. 100, No. 5, (Nov 2008), pp. 375-383,

Khamis et al described a new technique with modified abutments in implant-retained auricular prostheses, using a single- stage surgical procedure.

• They have screwed the modified O-ring abutments directly onto the implants at the time of surgery.

• Plastic washers were attached to the O-ring heads of the exposed abutments to avoid skin over growth to allow a single-stage surgical procedure.

• After a osseointegration period of 4 months, a silicone prosthetic ear was fabricated and retained using clips over the O-ring abutments

Complications • Retrospective study of treatment outcomes with implant-retained extraoral prostheses:

Survival rates and prosthetic complications. ( J Prosthet Dent 2010;103:118-126)

• Complications related to auricular prosthesis are the 1)loosening of abutment

2)broken bar or extensions 3)loosening of prosthetic bar screws, 4) broken or lost clips, loss of clip retention, loss of magnet retention, 5) fractured acrylic resin substructure 6)loss of bonding between substructure and silicone, deposits on tissue surface of the prosthesis,

.

7) and tear or rupture of the prosthesis8)Loosening of bar screws is another relatively frequent

complication noted in auricular prosthesis.Therefore, the screws should be placed with proper torque control, ensuring complete seating of the driver into the screw head.

The most frequent complications are mechanical failures of the substructure and retentive attachments, including acrylic resin substructure fracture, clip fracture, and loss of attachment between the silicone and substructure.

• According to the literature survey of Gumieiro et al, auricular osseointegrated implants have presented survival rates varying according to the length of follow-up, ranging from 92% after 8 years to 100% with shorter follow-up. However, there have been limited clinical studies on the life span of extraoral prostheses.

Nasal prosthesis

Nasal prosthesis

• Throughout the history the nose has been described as the object of beauty and symbol of strength. The amputation of nose has been the bitter price of social dishonor and even the reason for military conflict in the history.

In the total nasal defect, there is usually sufficient amount maxillary bone that creates the inferior border of the piriform aperture.

If the nasal defect involves only the lower portion of the nose, only two Osseointegrated implants inferiorly in the maxilla are enough or further resection of the remaining nose in the upper area is done to expose the nasal bones.

.

• For aesthetic reasons, glabella and lateral maxillary sites are poor choices for implants, because framework will interfere with the aesthetic formation of the nose

The state of the maxillary dentition and presence or absence of anterior teeth can be important diagnostic factors in selecting fixture type, length, and location.

Ventilation requirements for nasal prostheses are facilitated via perforations within the artificial nares.

Fixture sites for large midfacial defects are dictated by the residual anatomy. The residual zygomatic arches can also be used for the horizontal placement of long fixtures which offer excellent anchorage points.

Stage I An incision is made and the periosteum and skin are

elevated together. The location of the implants is marked, and a 4 mm implant is usually placed in the lower piriform aperture and 4 mm or 3 mm implants in the nasoethmoidal area. It is extremely important to use minimally traumatic technique, low speed drilling, and copious irrigation

Stage II Approximately 3 months after the first stage, It is preferred to open

the old incision and the flaps are thinned and the wound is approximated with a few sutures.

The holes for the penetration of the abutments are created with a

punch or a scalpel. The cover screws are removed, abutments are placed such that the abutment extends approximately 3 mm above the skin.

Healing caps are applied, and a moderately compressive dressing is used to facilitate adherence of the flaps and to limit edema formation. The wound is allowed for 2 weeks to heal before the prosthetic work is started.

Attachments : In general, metal bars work better in the area of the nose.

The bar has the additional advantage that it limits rotational forces on the implants. once the metal bars or magnets have been placed, the work of attaching the prosthesis can be started.

For nasal prostheses, a midline clip and framework retention is best in most cases.

The framework is designed to be cast in metal and is an inverted Y shape that has a cross brace between the widest part of the Y near the abutments.

The advantages of this design are that it:

1) Allows maximum bilateral air flow.

2) Provides for vertical and horizontal clip orientation,

preventing the misapplication of the facial prosthesis; and

3) Provides adequate access to the nasal cavity and peri abutment

tissues for hygiene maintenance.

Triangular segments of the Y should be as far away from the walls of the nasal cavity as possible, so cleaning of septal surfaces of the internal nose can be accomplished.

Restoration of nasal defect with implant-retained noseprosthesis.The Journal of Indian Prosthodontic Society | October 2007 |

Vol 7 | Issue 4

• This case report presents a patient with the excision of nose due to xeroderma pigmentosa rehabilitated with implant retained silicone nose prosthesis.

• Two cylindrical implants with a diameter and length of 3 mm and 10 mm were surgically inserted in the floor of the anterior maxilla.

• After a healing period of six months the implants were surgically exposed ,cover screws removed, and universally modified abutments (UMA) and healing caps attached

Healing caps were removed after 1 month and this was followed by the prosthetic phase

• Prosthetic phase• Impression posts were attached to the UMA for transferring the

position of the implants onto a stone cast .• Impressions of the nasal tissues were taken in a rubber base

impression without distorting the surrounding tissues. • Implant analogs were fixed to the impression post and master cast

was obtained .• Wax pattern of the retention bar (superstructure) was fabricated on

the master cast.

• The trial of the wax pattern on the face was taken. Subsequently, retention bar was casted in metal.

• After assessing the fitting of the retention bar, it was fixed on the UMA attached to the implants.

• The impression of the tissues was taken again .• The stone model for sculpting was obtained

• The sculpting of the prosthetic nose in wax to achieve appropriate size, contour, surface texture, and margins was done.

• Superior and superio-lateral portions of the lateral margin were positioned beneath the glass frame.

• The lower portion of the lateral margin was blended with the skin • The sculpted prosthetic nose was adapted on an acrylic

substructure.

• Acrylic resin substructure was adapted on the retentive bar. • It contains the retentive element – bar clip, which must fit within

the confines of the nasal prosthesis.• Sufficient surface area was ensured so that the bond between

the resin and silicone did not fail.

• The processing and flasking of the sculpted wax nose was performed for the fabrication of a silicone nose prosthesis with an acrylic substructure containing the bar clips.

• Implant-retained nasal prosthesis for reconstruction of large rhinectomy defects. International Journal of Oral and Maxillofacial Surgery April 2010, Pages 343–349

• Their technique of modifying post-rhinectomy defects is described and factors influencing implant success are evaluated.

• The overall success rate was 89% (99/111); 94% in patients who did not receive radiotherapy and 86% in those who did.

Areas of defect modification. Elephant’ shaped skin graft.

• The prosthesis was in place in all patients (100%) at the time of last follow up. Post-rhinectomy defect modification enables adequate access for safe placement of long implants with good primary stability and helps the maintenance of good hygiene (further enhanced by the use of skin grafts).

• The implant-retained prosthesis is a reliable option for reconstructing large full thickness rhinectomy defects. They suggest their technique of modifying the defect, use of long implants and magnets for retention is responsible for the high success rate of implants used to retain a nasal prosthesis.

• Zygomaticus implants were originally developed for dental reconstruction of the edentulous maxilla with severe bone resorption.

• The recent development of the zygomaticus implants has made nasal reconstruction more flexible as these implants can be placed horizontally from the middle of the nasal defect through the maxillary sinus under the eye, engaging the cortical bone of the zygoma.

• These implants are useful where the anterior maxilla has been lost and pyriform rim implants are not possible. Care is taken to avoid the infra-orbital nerve and injury to the eye.

• Malignant tumours of the nose occasionally require rhinectomy. Implant retained prostheses can give good aesthetic results.

Zygomaticus implants for retention of nasal prostheses after rhinectomy

British Journal of Oral and Maxillofacial Surgery 44 (2006) 54–5

• After rhinectomy zygomaticus implants orientated horizontally from the piriform aperture into the zygoma to retain the nasal prosthesis.

• Postoperative appearance with two zygomaticus implants orientated horizontally across the maxillary sinus and one intraoral implant in the glabella, all with Magna-Cap attachments.

• COMPLICATIONS• Soft tissue complications include inflammation,

bleeding, tissue overgrowth, granulation tissue and infection.

• Inflammation and excessive loading can cause bone resorption.

• Overloading, even after several years, can cause microfractures in the bone that heal into scar tissue and cause the implant to become loose.

• common problem with the nasal prosthesis is the contamination of the fitting surface with bacteria. This is due to the combination of warmth, moisture and normal nasal secretions.

• If bacteria are allowed to penetrate the silicone, difficulty is experienced in its removal. This particular problem can be avoided by ensuring that the patient is made aware of the cleaning regime for the prosthesis and the defect area.

MIDFACIAL PROSTHESIS

• Reconstruction of midfacial defects with implant insertion

• Mid-facial defect is one of the most disfiguring and impairing defects.

• A design of prosthesis that is aesthetic and stable can be precious to a patient who has lost part of his face due to surgical excision.

• Prosthesis can restore the patient’s self-esteem and confidence, which affects the patients and their life style.

Reconstruction of the maxilla and midface: Oncol. 2010 Oct, Vol. 11, No. 10, pp. 1001-8.

• The maxilla can be described as a geometrical structure with six walls (hexahedrium).

• Each wall is part of another anatomical structure in the face. The roof of the maxilla is the floor of the orbit and supports the ocular globe.

• The medial wall of the maxilla is the lateral wall of the nasal cavity and is part of the lacrimal system.

• Combining bone grafts with skin/soft tissue flaps simplifies reconstruction of the highly complicated three dimensional nature of the maxillary defect.

• Osseointegrated implants may be used in several different prosthesis designs.

• Craniofacial Site Classification.

• The dry skull study suggests a gross site classification based on anatomic location and bone volume for appropriately placed fixtures.

• Given these limitations, craniofacial implant sites can be classified into three groups:

• Alpha sites are 6 mm or greater in axial bone volume, permitting the use of dental implants. These locations can be used to partially retain denture or complex facial prostheses.

• The most common areas of the facial skeleton having that much bone available are the anterior maxilla through the nasal fossa and the zygoma and/or zygomatic arch when using a bicortical engagement technique with long implants traversing the inner face of the zygomatic arch

• Beta sites have 4 to 5 mm of bone volume available, permitting the use of a 4-mm craniofacial implant or 5-mm fixture. Beta sites encompass the superior, lateral, and inferolateral orbital rims as well as much of the temporal bone and zygoma.

• 3. Delta sites are marginal sites with 3 mm or less of bone volume available.

• Locations in the temporal bone, pyriform rim, infraorbital rim, nasal bone, zygomatic buttress, and zygomatic arch require the use of 3-mm craniofacial implants in series.

• A 58-year-old male had a 10-year history of adenocystic carcinoma of the midface with early metastasis to the right lung. The patient was markedly disfigured in the nasofacial area.

• He could not open his mouth, had difficulty in speaking, and could not breathe through the nose.

• Definitive excision of the midfacial lesion included radical rhinectomy, 90% total maxillectomy, complete upper labialectomy, and bilateral partial malarectomies.

• The left zygoma was reduced by about 50% and the right by 25%. The right side also retained a small section of the zygomatic buttress.

• The maxilla was almost completely removed; only the second molar on each side and a 4-mm-wide interconnecting portion of the most posterior hard palate remained.

• The soft plate was not disturbed. The upper lip, both cheeks up to the orbits, and all nasal soft tissues were removed

• At the time of ablative surgery, two 18-mm implants were placed into the malar bones bilaterally using the curve of the zygomatic arch to allow for bicortical engagement.

• The implants were placed approximately parallel to the Frankfort horizontal plane but angled sagittally and placed vertically to each other about 5 mm apart.

• On the right side, the inferiorly placed implant was inserted in the zygomatic buttress area, where 4 to 5 mm of bone width was available. It went through the posterior aspect of the buttress and engaged the zygomatic arch

• The implants were exposed 6 months after surgery and 5.5-mm abutments were placed.

• Elastomeric impressions were made immediately following resection of the facial tumor. An immediate surgical obturator was then fabricated and worn provisionally during the healing period.

• Hadar clip retention is built into gold bars attached to two 18-mm implants placed into the zygomatic arch bilaterally.

• Magnetic attachments were positioned on the facial surface of the maxillary obturator and the inner surface of the acrylic resin mesostructure to aid in stabilization of the obturator yet allow for functional occlusal movements during mastication .

.

The bars provide retention through a mesostructure for a large obturator prosthesis.

The mesostructure aligns with the denture via magnetic attachments and secures it secondarily after attachment to the gold bars with four Hader clips.

• A circumferential retentive undercut was formed in the acrylic resin of the mesostructure to help the retain the composite facial silicone prosthesis, which extended from the bridge of the nose laterally to the zygomatic areas, inferiorly to the buccal vestibule, then medially to the lower lip and across to the midline.

• This included total replacement of the upper lip with the silicone facial prosthesis.

• The denture also attaches to the second molars present bilaterally.

• The composite facial prosthesis extends from glabella to stomion, including the bridge of the nose, zygomatic areas, buccal vestibule, and full upper lip.

• The patient is able to wear glasses, which in this instance had to rest on the prosthesis itself. The patient can breathe through the prosthetic nose, articulate normally, and masticate satisfactorily.

• He is hampered by the lack of sensation in his upper lip but is able to drink from a glass and suck through a straw.

• The patient has functioned with this prosthesis for 3 years and is able to eat a fairly normal diet.

• However, he continues to have problems retaining food intraorally because of lack of sensation in the upper lip and lack of maxillary buccal vestibule.

• Intraoral suction is achieved by pursing his lower lip against the silicone facial prosthesis.

• Salivary control is slightly hampered because of the loss of the left commissure and part of the lower lip to the resection.

A 63 year old man, was exposed to repeated surgical procedures over several years, because of a basal cell carcinoma of his face. After 10 years, tumor histology changed into a squamous cell carcinoma.

A decision was made to provide him with not only a facial prosthesis but also an implant supported fixed bridge in the maxilla using osseointegrated fixtures. Preoperative examination revealed that the quantity of maxillary bone was not sufficient for a standard procedure, so a bone graft had to be used.

Framework:• The purpose of a fixed framework or substructure is to

retain the facial prosthesis.• Two conventional bar constructions were made, one on

the three upper and the other on the three lower maxillary abutments

A third part of the framework connects the two bar constructions. This part of the construction has an exceptionally long span. Therefore, a Custom made three dimensional framework was prepared.

The goal was to achieve stiffness with low weight. These fittings were then soldered to the bar splints and enabled to connect the three parts of the construction.

.

• The entire framework was made out of a pre machined gold alloy clasp wire 2 mm in diameter, which was bent and soldered to conventional 3 mm gold cylinders

SKIN RESPONSE AT ABUTMENT SITE

Skin response to Percutaneus abutments has also been

considered as an indicator of success, by rating it on a five

point scale.

This five point scale is a result of the work of Holgers et al in

1987 and has been adopted widely.

Class Description

0 No irritation: epithelial debris removed if present.

1 Slight redness: temporary local treatment.

2 Red and slightly moist tissue; no granuloma formation:

local treatment; extra controls.

3 Reddish and moist; sometimes granulation tissue: revision surgery is indicated.

4 Removal of skin-penetrating implant necessary as a result of infection.

R Removal of implant for reasons not related to skin problems.

FALLOW UP AND MANAGEMENT

Once a patient is treated, the osseointegration team has to undertake a lifelong responsibility for the maintenance of the bone anchored prosthesis. Much time and effort are spent in the fabrication of a bone anchored prosthesis that will provide a lifelike facial restoration.

For all of its advantages, the bone anchored facial prosthesis does require more care on the patient's part and closer professional follow up than one retained with adhesive.

Follow up management actually begins once the abutments have been placed.

After the initial healing period and once a surgical dressing is no longer needed, the patient should be instructed to clean this area on a daily basis. The purpose is to remove cellular material on the skin or abutment, which can come from the interface of the epithelium and abutment.

End tuft tooth brush Interproximal tooth brush Cotton swab

This is performed with a soft end nylon bristle toothbrush, an interproximal dental brush, or a cotton swab. To facilitate cleaning, the area should be moistened first with an even mixture of hydrogen peroxide and water to soften any dried debris.

• The prosthodontist should monitor the stability of the abutment and the health of the soft tissue during the regularly scheduled visits for prosthesis fabrication.

Abutment clamp provides counter torque for checking abutment tightness.

• Abutment tightness can be checked using a abutment clamp. If the abutment loosens, complete seating should be verified before retightening. This is done with an abutment holder.

Abutment holder ensures complete seating of loose abutment.

On the day that the prosthesis is given to the patient, adequate time should be allotted for instructions on placing and removing the prosthesis as well as proper maintenance of the prosthesis, abutments, and surrounding skin areas.

When placing the prosthesis, the patient should be certain that the retentive elements are engaged completely to ensure that the prosthesis is seated fully. The retention elements (clips, magnets, or balls or studs) within the acrylic resin plate ensure security of the prosthesis.

The patient should be careful when removing the prosthesis so that the thin margins do not tear and the silicone rubber does not separate from the resin plate.

For an auricular or nasal prosthesis, proper removal by grasping a thick portion of the prosthesis and slowly disengaging the retentive elements should be demonstrated and performed several times by the patient.

For an orbital prosthesis, an outer margin should be lifted carefully until a thicker portion can be grasped to lift the prosthesis.

Review of literature

George E. Anastassov and Eric S. Asher (JPD 2000;84:215-16)

stated that the soft tissues overlying the percutaneous implants

are usually thick and mobile, which requires longer

transcutaneous attachments. However these attachments may

compromise the stability of the implants and lead to the implant

loss. To avoid these complications skin and subcutaneous

debulking and split thickness skin grafts should be performed.

Stephen M. Parel. P I Branemark et al states that the

application of osseointegrated fixtures to the cranial skeleton

for facial prostheses retention marks revolutionary step in

search for the perfect soft tissue replacement. They along

present Eastover technology to be used to its greatest

potential by protecting surface color and allowing long term

retention of fine but weak peripheral margins.

Albertson et al conducted 951 clinical observations of skin

response around 389 abutments for BAHA(243 observations)

and auricular prostheses (708 observations). Of these

observations 92.1% showed no skin response and 3.9%

showed slight redness, potentially serious skin responses

occurred in only 2.8% of observations.

Rubinstein reported that orbital prostheses were fabricated

with wider variety of attachments than any other type bone

anchored facial prostheses: bar clips, magnets, ball studs, or a

combination of these types.

In review of treatment centers Rubenstein found that magnetic

retention represented nearly half of the attachments in united

states and Canada compared with only one third of those

used in Sweden. Clips were used only 20% of the time in

united states, 33% of the time in Canada and nearly 50% of

the time in Sweden. Approximately 20% of the orbital

prostheses in the united states and Sweden used a

combination of magnets and clips.

References• Osseointegration in Maxillofacial reconstruction :

Per-ingvar branemark, Dan E. Tolman.

• Advanced Osseointegration Surgery – application in

maxillofacial region:

Philip Worthington, Per-ingvar Branemark.

• Maxillofacial rehabilitation:

Keith F. Thomas.

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3. Console abutment loading in Craniofacial osseointegration

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Int J oral maxillofac implants 2004;19:901-05.

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Extraoral applications Prosthet dent 1986;55:600-06.

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11. Surgical considerations for endoosseous implants in the

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12. Diminishing dependence on adhesives for retention of

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13. The use of magnets in maxillofacial prosthesis.

J Prosthet dent 1971;25:334

14. Osseointegrated implants for replacement of absent or

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