• Estimation of the difficulty of access should be made to ensure
feasibility of surgical instrumentation.
• Expected load and resistance are assessed well in advance.
• Implant-supported auricular, ocular and nasal prostheses are well
• For implant-supported auricular prosthesis, minimum two implants
are used in the temporal bone from the centre of the external
auditory meatus 15 mm from each other.
• For nasal implant-supported prosthesis, minimum two implants are
placed in the lateral rounded nasal eminences.
• For implant-supported ocular prosthesis, three to four implants are
placed in the superior, lateral and inferior orbital rims.
Retention aids in maxillofacial
Successful prosthetic rehabilitation of the maxillofacial defect needs
adequate retention, stability, support and acceptable aesthetics.
Retention is defined as ‘that quality inherent in the dental prosthesis
acting to resist the forces of dislodgement along the path of placement’. (GPT
Classification of retention aids
According to Chalian V.A., retention can be extraoral or intraoral.
• Anatomical – soft and hard tissues
• Mechanical – magnets, snap buttons, straps,
• Anatomical – soft and hard tissues
• Mechanical – temporary and permanent
It is essential to use both hard and soft tissues of the head and neck
region for retention. Retention in the extraoral area depends on
• Weight of the final prosthesis
Hard tissues: These behave as a base against which
the prosthesis is seated to provide excellent seal of
the prosthesis with the use of adhesive.
Soft tissues: Difficulty in achieving retention in soft
• Less resistance to displacement
• Physiological nature of the ectodermal tissues
Additional retention is required in cases where large defects are
present involving one-half of the face or tissues are heavily radiated
where adhesives are not useful to retain the prosthesis. Eyeglasses can
be used as an indirect mechanical retention aid. The eyeglasses should
be kept free of the prosthesis and should not be a part of it. An elastic
strap is often useful to hold the eyeglasses and retain the prosthesis.
Magnets: These are embedded in the nasal or the orbital prosthesis to
aid in retention of the extraoral prosthesis.
Snap buttons and straps: These are useful in retaining large extraoral
Adhesives: These help in enhancing retention of the prosthesis by
means of surgical grade extraoral adhesive. The adhesives aid in
retention, marginal seal and border adaptation. These help in
securing the prosthesis against accidental dislodgement.
• Intraoral retention should be derived from the both hard and soft
tissues, i.e. the remaining teeth, mucosal and bony tissues. The
amount of retention depends on the size and location of the defect.
• Anatomical undercuts aid in retention of the prosthesis.
• Large alveolar ridges and high-arched palate provide more
retention than the flatter ridges and shallow palate.
• Intraoral anatomical retention can also be achieved by providing
proper occlusion, surface adhesion and proper post damming.
This can be of two types, namely, temporary and permanent.
Temporary mechanical retention
• Stainless steel wrought wire of 18 gauge can be used in retaining
temporary prosthesis during the healing period.
• Preformed wire clasps can be incorporated in the prosthesis or
Adams’ arrowhead clasps can be used.
Permanent mechanical retention
• Cast clasps are the most commonly used as these also provide
stability, splinting, bilateral bracing and reciprocation.
• Prefabricated precision attachments.
• Snap-on attachment (e.g. Baker bar or Anderson bar) is a rod
connecting two abutment crowns and the clip is used to engage the
• Overlay crown/thimble crown is a telescopic crown which is used
on extremely malposed abutment teeth.
• Magnets are useful in hemimaxillectomy cases or highly resorbed
• Swing-lock devices are indicated in periodontally compromised
dentition when other methods are ruled out.
• Implants are widely used intraorally to retain prosthesis.
• Suction cups are inflatable balloon suction cups which are useful in
• Adhesives: Their use is limited and should be avoided in the regions
of perspiration or tissues undergoing radiation or surgery. These
can be used with materials made with resilient materials.
• Occlusion: Proper occlusal contact is important for prosthesis
Role of magnets in maxillofacial prosthesis
A magnet is defined as ‘a material which has the ability to attract iron and
lie in a north–south direction when suspended. Strongly magnetic substances
are known as ferromagnetic (iron, steel, cobalt, nickel and alloys of these
These can be used to aid in retention in maxillofacial prosthodontics
utilizing both attractive and repulsive properties.
(i) Rare earth metals (Nd–Fe–B and Sm–Co)
• These are encapsulated in acrylic resin and are attached to extension
• Paired magnets are also resin encapsulated with wires attached to
• These allow better retention without compromising on the
• These allow retention to be placed remotely from the fixture base for
• In areas of high muscle activity adjacent to the prosthesis
• In areas of muscle activity combined with a rigid prosthesis
• In patients with poor digital dexterity
• Excellent retentive qualities
• Increased patient satisfaction and security
• Marginal integrity is maintained allowing fabrication
• Extended longevity without necessity for constant remake or repair
• Rapid prototyping technology used in maxillofacial prosthodontics
is used to create three-dimensional models from a threedimensional representation (CT scan or MRI).
• Essig splint is used to stabilize fractured or repositioned teeth and
• Inflatable balloon obturators were first described by K.W. Coffey
in 1984. These are used to minimize displacement of the soft tissues.
33. Diagnosis and treatment planning
34. Osseointegration and materials
35. Surgical and prosthetic phase
Dental Implant and its Scope and Limitations, 456
Historical Background of Dental Implants, 456
Radiographic Planning of Dental Implants, 460
Role of Radiographs in Implant Treatment, 461
Role of CT Scans in Implant Dentistry, 461
Role of Radiographic Stent in Treatment
Planning in Implant Dentistry, 463
Bone Density—a Key Determinant for
Treatment Planning in Implants, 463
Dense to Thick Porous Compact and Coarse
Porous Compact and Fine Trabecular Bone
Fine Trabecular Bone (D4), 464
Importance of Evaluating Edentulous Ridge for
The use of implants in dentistry has become an indispensible tool in
rehabilitation of partially or completely edentulous patients. Their use
has improved not only oral functions but also quality of life of an
Dental implant and its scope and
Dental implant is defined as ‘a prosthetic device made of alloplastic
materials implanted into the oral tissues beneath the mucosal or/and
periosteal layer, and on/or within the bone to provide retention and support
for a fixed or removable dental prosthesis’. (GPT 8th Ed)
Historical background of dental implants
• 600 AD: First evidence of dental implants was found in the Mayan
civilization. Ancient Egyptians implanted animal teeth or teeth
• 1000–1799 AD: Medieval period was primarily concerned with
transplantation of teeth. Albucusis fabricated implants made of
• 1809 AD: Maggiolo inserted gold roots into freshly extracted sockets
• 1906: Greenfield first described and inserted endosseous implant
which was round basket-shaped and hollow, made of iridium–
• 1939: Strock anchored vitallium screw into the bone and placed
porcelain crown on the implant.
• 1943: G.S. Dahl first advocated subperiosteal implant. He fabricated
a metal structure on the maxillary alveolar crest with four projecting
• 1948: N.I. Goldberg and A. Gershkoff fabricated a subperiosteal
implant with an extension of the framework on the external oblique
• 1953: Sollier, R. Chercheve and Small introduced the transosteal
• 1965: P.I. Branemark first placed endosseous dental implant made of
• 1966: L.I. Linkow introduced the blade vent implant which were
originally designed for knife edged ridges but were later adopted
for other clinical situations.
• Late 1960s: A. Roberts and R. Roberts developed the ramus blade
endosseous implant. This type of implant was made of 316 stainless
steel and was anchored between the two cortical plates.
• Early 1970s: C.M. Weiss and K.W. Judy used the intermucosal
inserts for retaining maxillary removable prosthesis.
• Early 1970s: Roberts and Roberts developed the ramus frame
implant which received anchorage bilaterally from the mandibular
• 1974: IMZ implant system was introduced. The speciality of this
system was that it used elastic compensating component which was
inserted between the osseointegrated implant and the prosthetic
superstructure. It has two components, one implant body and the
other intramobile connector (IMC).
• Mid-1970s:Branemark developed the Nobelpharma implant
• 1982: Branemark introduced the first commercial implant made of
pure titanium. It became a standard by which all other root from
• Early 1980s: Gerald A. Niznick developed the internal hex-threaded
design for better implant stability.
• Late 1980s: Plasma-sprayed and hydroxyapatite-coated implants
• Early 1990s: Frialit 2 system were developed by Dentsply, which
had excellent prosthetic options.
• Inability of the patient to wear removable partial or complete
• Need for long-span fixed partial denture with questionable
• Unfavourable number and location of the potential natural tooth
• Single tooth loss that would necessitate preparation of minimally
restored teeth for fixed prosthesis
Contraindicationshttps://www.mawadealmaousoaa.com/2022/10/conciseprosthodonticsprepmanualpdf.html
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