DR SALAH HEGAZY Introduction To Dental Implant Definition

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Dental Implant

• DR SALAH HEGAZY

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Introduction To Dental Implant

• Definition
• Materials used for dental implant.
• Types of dental implant
• Osseointegration
• Biomechanics of osseointegrated implant.

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Definitions

• Oral Implant
• A device or inert substance, biologic or
  alloplastic, that is surgically inserted into
  soft or hard tissues, to be used for functional
  or cosmetic purposes.
• Dental Implant
• A permucosal device which is
  biocompatible and biofunctional and is placed
  within mucosa or, on or within the bone
  associated with the oral cavity to provide
  support for fixed or removable prosthetics.

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Or Dental implant

• prosthetic device of alloplastic material
  implanted in oral tissues beneath the mucosal
  or/and periosteal layer, and /or within the bone
  to provide retention support for a fixed or
  removable prosthesis
• Made of various biomaterial. Most commonly made
  of titanium (most compatible with human biology)

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introduction

• Losing tooth/teeth is not new problem
• It is possible to replace teeth that look
  function like natural teeth
• Implants is one of the means of achieving this
  through osseointegration (biological adhesion of
  bone tissue titanium)
• Pioneered by prof. Per-Ingvar Branemark in 1952
  ( Swedish orthopedics' surgeon)

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Dental implants
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Advantages disadvantages of implant over
conventional treatment

• Implants do not involve preparation of the
  adjacent teeth, they preserve the residual bone,
  and excellent aesthetics can be achieved.
• However, it is expensive, the patient requires
  surgery, time consuming, and technically complex.

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Types of dental implant

• Mucosal Insert
• Endodontic Implant (Stabilizer)
• Sub-periosteal implant
• Endosteal or Endosseous implant
• Plate-form implant
• Ramus-frame implant
• Root-form implant
• Transosseous implant

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1. Titanium Mucosal Insert
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2. Endodontic Implant (Stabilizer)

• Endodontic implants are similar to
  prosthodontic implants in many respects. However,
  they serve another purposethe stabilization and
  preservation of remaining natural teeth, not the
  replacement of lost teeth.

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3. Sub-periosteal implant

• Subperiosteal Implants were already
  introduced in the 1940s. Of all currently used
  devices, it is the type of implant that has had
  the longest period of clinical application. These
  implants are not anchored inside the bone, such
  as Endosseous Implants, but are instead shaped to
  ride on the residual bony ridge of either the
  upper or lower jaw. They are usually not
  considered to be osseointegrated implants.
• Subperiosteal Implants have been used in
  completely edentulous as well as partially
  edentulous upper and lower jaws. However, the
  best results have been achieved in treatment of
  the edentulous lower jaw.

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• Indications
• Usually a severely resorbed, completely
  edentulous, lower jaw bone which does not offer
  enough bone height to accommodate Root form
  Implants as anchoring devices.

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5. Endosteal or Endosseous implant

• Plate-form implant
• Blade Implants have a long track record,
  much longer than the Root form Implants. Their
  name is derived from their flat, blade-like (or
  plate-like) portion, which is the part that gets
  embedded into the bone.

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• Blade implants are not used too frequently
  any more, however they do find an application in
  areas where the residual bone ridge of the jaw is
  either too thin (due to resorption) to place
  conventional Root form Implants or certain vital
  anatomical structures prevent conventional
  implants from being placed. Nowadays, if a
  certain area of the jaw bone is too thin and has
  undergone resorption due to tooth loss it is
  recommended to undergo a Bone grafting procedure,
  which re-establishes the lost bone, so that
  conventional Root form Implants can be placed.

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Ramus-frame implant

• Ramus-frame Implants belong in the
  category of endosseous implants, although their
  appearance might not suggest that at first.
• These implants are designed for the
  edentulous lower jaw only and are surgically
  inserted into the jaw bone in three different
  areas the left and right back area of the jaw
  (the approximate area of the wisdom teeth), and
  the chin area in the front of the mouth.
• The part of the implant that is visible
  in the mouth after the implant is placed looks
  similar to that of the Subperiosteal Implant.

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Ramus-frame implant

• Indications
• Usually a severely resorbed, edentulous
  lower jaw bone, which does not offer enough bone
  height to accommodate Root form Implants as
  anchoring devices. These implants are usually
  indicated when the jaws are even resorbed to the
  point where Subperiosteal Implants will not
  suffice anymore.

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• An additional advantage that comes with
  this type of implant is a tripodial stabilization
  of the lower jaw. A jaw as thin as the one shown
  above can easily fracture at its thinnest part.
  The Ramus-frame Implant, once integrated (after a
  three month waiting period) will also stabilize
  and protect the jaw somewhat from fracturing.

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The Ramus-frame Implant usually comes in a
standard pre-shaped form and needs to be
custom-fitted to the patient's individual jaw
dimension, as shown below
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Ramus-frame implant
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• Root form implant
• Since the introduction of the
  Osseointegration concept and the Titanium Screw
  by Dr. Branemark, these implants have become the
  most popular implants in the world today.

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• Root form Implants come in a variety of
  shapes, sizes, and materials and are being
  offered by many different companies worldwide.
  Some clinicians regard them to be the Standard of
  Care in Oral Implantology.
• These implants can be placed wherever a
  tooth or several teeth are missing, when enough
  bone is available to accommodate them. However,
  even if the bone volume is not sufficient to
  place Root form Implants, Bone grafting
  procedures within reasonable limits should be
  initiated, in order to benefit from these
  implants.

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• Root form implant shape
• Other variations dwell on the shape of the Root
  form implant. Some are screw-shaped, others are
  cylindrical, or even cone-shaped or any
  combination thereof.

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• Today, the most accepted material for dental
  implants is high grade Titaniumeither CP
  Titanium or an alloy thereof. The titanium alloy
  implants tend to be stronger than the CP titanium
  implants. The bone integration shows no
  difference to the two different types of
  titanium.
• Some implants have an outer coating
  of Hydroxyapatite (HA). Other implants have their
  surface altered through plasma spraying, or
  beading process. This was developed to increase
  the surface area of the titanium implant and,
  thus, in theory, give them more stability. These
  surface treatments were also offered as an
  alternative to the HA coatings, which on some
  implants have shown to break loose or even
  dissolve after a few years.

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Transosseous implant

• These implants are not in use that much
  any more, because they necessitate an extraoral
  surgical approach to their placement, which again
  translates into general anesthesia,
  hospitalization and higher cost, but not
  necessarily higher benefits to the patient.
• In any case, these implants are used
  in mandibles only and are secured at the lower
  border of the chin via bone plates. These were
  originally designed to have a secure implant
  system, even for very resorbed lower jaws.

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The two attachments
long screw posts
The plate

• A typical Transosseous Implant. The plate
  on the bottom is firmly pressed against the
  bottom part of the chin bone, whereas the long
  screw posts go through the chin bone, all the way
  to the top of the jaw ridge inside the mouth. The
  two attachments that will eventually protrude
  through the gums can be used to attach an
  overdenture-type prosthesis.

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Osseointegration

• Definition
• A time-dependant healing process
  where by clinically symptomatic rigid fixation of
  alloplastic materials is achieved, and
  maintained, in bone during functional loading.
  (Zarb Albrektson,1991)

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Factors affecting osseointegration

• Implant biocompatibility
• Implant design
• Implant surface
• Implant bed
• Surgical technique
• Loading condition

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Implant biocompatibility

• Materials used are
• Cp titanium (commercially pure titanium)
• Titanium alloy (titanium-6aluminum-4vanadium)
• Zirconium
• Hydroxyapatite (HA), one type of calcium
  phosphate ceramic material
• Osseointegration interface
• Osseointegration
• Biointegration

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Implant design (root-form)

• Cylindrical Implant
• Some investigators explain the lack of
  bone steady state by overload due to
  micromovement of the cylindrical design, whereas
  others incriminates an inflammation/infection
  caused particularly by the very rough surfaces
  typical for these types of implant.
• Threaded Implant
• In contrast, Threaded implants have
  demonstrated maintenance of a clear steady state
  bone response.
• To enhance initial stability and increase surface
  contact, most implant forms have been developed
  as a serrated thread.

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Implant surface

• Pitch, the number of threads per
  unit length, is an important factor in implant
  osseointegration. Increased pitch and increased
  depth between individual threads allows for
  improved contact area between bone and implant.
• Moderately rough surfaces with 1.5µm
  also, improved contact area between bone and
  implant surface.
• Reactive implant surface by anodizing
  (Oxide layer) ,acid etching or HA coating
  enhanced osseointegration

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Bone Quality
According to Lekholm and Zarb.,1985

• Quality I
• Was composed of homogenous compact
  bone, usually found in the anterior lower jaw.
• Quality II
• Had a thick layer of cortical bone
  surrounding dense trabecular bone, usually found
  in the posterior lower jaw.
• Quality III
• Had a thin layer of cortical bone
  surrounding dense trabecular bone, normally found
  in the anterior upper jaw but can also    be seen
  in the posterior lower jaw and the posterior
  upper jaw.
• Quality IV
• Had a very thin layer of cortical
  bone surrounding a core of low-density
  trabecular bone, It is very soft bone and
  normally found in the posterior upper jaw. It
  can also be seen in the anterior upper jaw.

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Surgical technique

• Minimal tissue violence at surgery is
  essential for proper osseointegration.
• Careful cooling while surgical drilling is
  performed at low rotatory rates
• Use of sharp drills
• Use of graded series of drills
• Proper drill geometry is important, as
  intermittent drilling.
• The insertion torque should be of a moderate
  level because strong insertion torques may result
  in stress concentrations around the implant, with
  subsequent bone resorption.

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Loading condition

• Delayed loading
• A tow-stage surgical protocol
• One-stage surgical protocol
• Immediate loading
• Immediate occlusal loading (placed within 48
  hours postsurgery)
• Immediate non-occlusal Loading (in single-tooth
  or short-span applications)
• Early loading (prosthetic function within two
  months)

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Biomechanics of osseointegrated implant.

• In all incidences of clinical loading,
  occlusal forces are first introduced to the
  prosthesis and then reach the bone implant
  interface via the implant. So far, many
  researchers have, therefore, focused on each of
  these steps of force transfer to gain insight
  into the biomechanical effect of several factors
  such as
• Force directions and magnitudes,
• Prosthesis type,
• Prosthesis material,
• Implant design,
• Number and distribution of supporting implants,
• Bone density, and
• The mechanical properties of the bone-implant
  interface.

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Dental Implant Treatment Planning and Types of
Dental Implants

• How many teeth are missing?
• What is the degree of bone loss?
• Are the remaining teeth in a good position and do
  they have a long-term prognosis?
• What does the patient expect for an end result?
• What treatment will result in the best cosmetic
  outcome?
• What is the patient's budget?

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• Overall...
• What is the most
  practical and feasible implant treatment that
  will produce optimal chewing function and optimal
  cosmetic results in a timely and affordable
  manner?

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Super structure

• It could be defined as a metal framework that
  fits the implant abutments and provides retention
  for the prosthesis. Recently, it is defined as
  the superior part of multiple layer prosthesis
  that includes the replaced teeth and associated
  structures

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Diagnosis and Treatment Planning

• The evaluation of a patient as a suitable
  candidate for implants should follow the same
  basic format as the standard patient evaluation,
  although some areas require additional emphasis
  and attention
• Medical History.
• Psychological Status.
• Dental History.

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I. Medical History

• The patients medical history may
  reveal a number of conditions that could
  complicate or even contra-indicate implant
  therapy. These include
• Bleeding disorders Pagets disease A history of
  radiation therapy in the maxilla or mandible
  region Uncontrolled diabetes Epilepsy that
  presents with more than one grand mal seizure per
  month
• In addition, there are a host of systemic medical
  conditions, including steroid therapy,
  hyperthyroidism, and adrenal gland dysfunction
• Substance abuse including tobacco and alcohol

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II. Psychological Status

• If the patient cannot come to terms
  with the possibility of failure, or four to six
  months of potential discomfort and inconvenience,
  then he or she is not a suitable candidate for
  implant therapy.

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III. Dental History

• It is also vital to evaluate the
  patients chief complaint, as it may have an
  equal bearing on treatment outcome.
• For example, the treatment plan
  recommended to the patient desiring a more secure
  lower denture will be quite different from the
  one proposed to the patient seeking a fixed and
  rigid appliance.

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Implant Guidelines

• Diagnostic phase
• Problem list treatment considerations
• -radiographic analysis
• surgical analysis
• esthetic analysis

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Implant Guidelines

• Diagnostic phase
• radiographic analysis
• surgical analysis
• esthetic analysis

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Implant Guidelines

• Diagnostic phase
• radiographic analysis
• periapical pathology
• radiopaque/radiolucent regions
• adequate vertical bone height
• adequate space above inferior alveolar nerve or
  below maxillary sinus

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Implant Guidelines

• Diagnostic phase
• Problem list treatment considerations
• radiographic analysis
• adequate interradicular area
• bone quality quantity
• radiographs - panoramic and periapical (CT
  scan or tomography - as indicated)

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Implant Guidelines

• Diagnostic phase
• radiographic analysis
• radiographs - aid to determine amount of space
  bone available
• CT (computed tomography) scan - gives more
  accurate reliable assessment of bone (quality,
  quantity width) locale of anatomic structures

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Implant Diagnostic Guidelines

• Diagnostic phase
• radiographic analysis -
• radiographic stent - (can double as surgical
  stent)
• acrylic stent with lead beads or ball -bearings
  (5mm) placed in proposed fixture locations
• allows more accurate radiographic interpretation

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Implant Guidelines

• Treatment planning phase
• Problem list treatment considerations
• surgical analysis -
• implant length/diameter
• determined by quantity of bone apical to
  extraction site
• use longest implant safely possible
• diameter dictated by corresponding root anatomy
  at crest of bone

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Implant Guidelines

• Treatment planning phase
• Problem list treatment considerations
• surgical analysis
• treatment options
• immediate - place implant at time of tooth
  extraction
• delayed immediate - 8-10 week delay
• delayed - 9-10 months or longer
• immediate will not allow bone resorption, but
  delayed allows bone fill for stabilization

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Implant Guidelines

• Treatment planning phase
• Problem list treatment considerations
• surgical analysis
• proper surgical technique during implant
  placement is critical
• minimal heat generation important

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• Treatment planning phase
• Problem list treatment considerations
• radiographic analysis
• surgical analysis
• esthetic analysis

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• Treatment planning phase
• Problem list treatment considerations
• esthetic analysis
• implant emergence profile
• restored implant should appear to grow or
  emerge from the gingiva
• very natural desirable in appearance

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• Treatment planning phase
• Problem list treatment considerations
• esthetic analysis
• smile line - high in maxilla low in mandible
• lip shape - full Vs. thin
• existing ridge defect - if visible with high
  smile line will need augmentation

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The superstructure for completely edentulous
patients can be classified as follows

• Implant retained removable overdenture
• Implant supported removable overdenture
• Fixed detachable prosthesis (Hybrid prosthesis)
• Implant supported Fixed Bridge
• 1) Screwed-in Fixed Bridge
• 2) Cemented Fixed Bridge

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Design Concepts for Removable Implant
Prostheses
Resilient
Rigid

• Removable options can now be
  either nonrigid (resilient) or rigid. A removable
  rigid overdenture will function in a similar
  manner as a fixed implant prosthesis.

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Resilient Design

• Removable implant prostheses can be
  restored using a combined implant-retained
  and soft tissue-supported overdenture (ie, the
  two- implant overdenture).
• Fabrication of this type of
  restoration can be completed using individual
  unsplinted retainers that allow rotation or a
  bar-clip prosthesis equipped with a hinging
  mechanism for rotation. The use of a bar (ie,
  Dolder bar-joint) allows movement between the two
  components.
• In either case, the classic
  principles of complete denture fabrication apply
  adequate denture base extension and proper
  adaptation are essential. These design concepts
  should not be extrapolated to the maxillary arch.

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Rigid Design

• The implant-retained and implant-supported
  removable overdenture (ie, multiple implant bar
  overdenture with three or more implants) may or
  may not require the same number of implants as
  the fixed and usually has multiple retentive
  elements.
• This type of prosthesis does not, however,
  contain a rotational device. The bar used in
  these types of restorations is a bar unit (ex,
  Dolder bar-unit). It allows no movement between
  the bar and sleeve.

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Treatment Plan Selection

• Treatment planning and the decision-making
  process is a balance between the patients
  preferences, finances and clinical factors.
• Understanding that cost is an initial barrier to
  case acceptance, a large percentage of patients
  may reject more expensive options that only
  include fixed prostheses.

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Clinical factors

• Quality, quantity, and shape of supporting
  alveolar bone.
• The cantilever design can be avoided if the
  implants are placed posterior to the foramen. A
  fixed option could be utilized but will display
  less teeth, while a removable option will provide
  increased tooth display. .
• A patient who has the bone quality to support a
  fixed prosthesis could also be a candidate for an
  implant overdenture supported by fewer implants.

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Extraoral Diagnostic Guidelines
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Intraoral Diagnostic Guidelines
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Implant-overdenture
The most common line of treatment
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Treatment Planning Determinants

• 1. Changes in Oral Structures in Edentulism
• 2. Posterior Ridge Anatomy
• 3. Occlusal Forces
• 4. Quality, Location and Quantity of Bone
• 5. Implant Size
• 6. Implant Location
• 7. Arch configuration
• 8. "Mapping" the Mandible
• 9. Cantilevering

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1. Changes in Oral Structures in Edentulism

• With successive denture treatments,
  it is common for the vertical dimension of
  occlusion to decrease as bone resorbs. This
  promotes an increased tendency toward a skeletal
  Class III relationship.

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2. Posterior Ridge Anatomy

• Posteriorly, poor ridge height, inadequate
  attached gingiva and compromised ridge shape
  cause increased horizontal movement of the
  prosthesis. This increases the lateral forces
  that are brought to bear on the anterior
  implants, and will affect bar and prosthesis
  design.

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Posterior Ridge Anatomy
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3. Occlusal Forces

• The maximum bite force of subjects with a
  mandibular denture supported by implants is 60 to
  200 higher than that of subjects with a
  conventional denture
• Edentulous patients that are predisposed to
  clenching and bruxing may be given the necessary
  "tools" to begin parafunctional habits once the
  implant bar is secured in place.

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Occlusal Forces Attachments
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4. Quality, Location and Quantity of
Bone

• The minimum buccal-lingual thickness of
  osseous tissue required to successfully place an
  implant is 5 mm.
• In order to achieve a 5.0 mm "flat" base,
  either the anterior ridge crest peak must be
  removed or a bone graft must be considered.

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5. Implant Size

• The greater the surface area of the
  implant-bone system, the less concentrated the
  force transmitted to the crest of bone at the
  implant interface. Similarly, the greater the
  surface area of the implant-bone system, the
  better the prognosis for the implant.
• For each 0.25 mm increase in diameter, the
  surface area of a cylinder increases by more than
  10 per cent
• For each 3.0 mm increase in length , the surface
  area of a cylinder increases by more than 10 per
  cent.

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Implant Size
0.25 mm diameter 3.0 mm length
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6. Implant Location

• Ideally, occlusal forces should be directed along
  the long axis of the implants. Therefore ,The
  angle of the osseous ridge crest is a key
  determinant of implant angulation.
• the distance between an implant and any adjacent
  "landmark" (natural tooth or another implant),
  which should be not less than 2.0 mm.

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The angle of the osseous ridge crest is a key
determinant of implant angulation.
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7. Arch configuration

• Mandibular arch forms may be classified as
  tapered or square.
• With tapered arch forms, the most posterior right
  and left implants in a four-implant treatment are
  often placed well around the "turn" of the arch,
  creating a "U" shaped design that is well suited
  to cantilevering,
• With a square arch, the four implants are usually
  placed in a relatively straight line. This
  "straight line" bar design is not well suited to
  cantilevering.

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8. "Mapping" the Mandible

• The anterior symphysis can be divided into five
  geographic sites
• A point, 6.0 mm anterior to each mental foramen,
  determines the most posterior boundaries, right
  and left.
• Another possible implant location occurs at the
  midline.
• Two additional sites are chosen on each side of
  the midline, spaced equidistantly between the
  midline and the respective distal sites.

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" Mapping" the Mandible
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9. Cantilevering

• The number of implants, their respective lengths
  and locations, the quality of bone support, the
  posterior ridge anatomy, occlusal forces, and the
  opposing dentition are of greater importance in
  determining the appropriate cantilever than a
  suggested formula.
• One method is to draw a line through the most
  anterior implant, and another through the two
  most posterior implants. The distance between the
  two lines can then be measured. A suggested
  maximum cantilever would be 1.5 times this
  distance.

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The distance between the two lines can then be
measured. A suggested maximum cantilever would be
1.5 times this distance.
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Cantilevering
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Treatment Planning

• When all the diagnostic information has been
  assembled, a variety of available treatment
  options must be assessed
• 1. One-Implant Overdenture
• 2. Two-Implant Overdenture
• 3. Three-Implant Overdenture
• 4. Four-Implant Overdenture
• 5. Five-Implant Overdenture

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One-Implant Overdentures

• Indications
• The maladaptive or dissatisfied denture patient
  who demands greater stability and oral comfort,
• Elderly patients desiring a more stable
  mandibular denture,
• Or, as a minimal implant treatment objective for
  the partially edentulous patient with severely
  compromised teeth in which removal would convert
  a patient to a fully edentulous state

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. Two-Implant Solitary Overdenture

• In the two-implant over-denture, an attachment is
  used to greatly enhance the retentive potential
  of what is essentially a tissue-supported
  prosthesis.
• If only two implants are placed, which are 13mm
  long or longer, and they are in dense bone, they
  can be left as individual supporting units with
  little risk.

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Two-Implant Solitary Overdenture
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2. Two-Implant Bar Overdenture

• If the two implants are 10 mm long or shorter, or
  the bone quality is compromised, then ideally
• They should be splinted.
• They should be at least 10 mm apart (in order to
  allow room for a clip or fastening mechanism)
• They should be no further than 18 mm apart in
  order to limit bar flexure.

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Two-Implant Bar Overdenture
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Two-Implant Bar Overdenture
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3. Three-Implant Overdenture

• The three-implant overdenture is still
  essentially a tissue-supported prosthesis with
  enhanced retention supplied by the attachment/bar
  complex.

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Three-Implant Over-denture
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4. Four-Implant Overdenture

• At this level, the prosthesis begins to
  derive a larger part of its support and retention
  from the implant/bar complex, and the importance
  of tissue support decreases.
• Also, the attachments selected for a four-implant
  bar over-denture can be more rigid, as the
  torquing forces generated by the prosthesis will
  be better tolerated.
• This number allows for some "insurance" in case
  one implant fails to integrate.

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Unsplinted Implant Overdenture
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Implant-Bar Overdenture
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5. Five-Implant Overdenture

• At this level, a prosthesis can be fabricated
  that is completely implant supported and
  retained, if the AP spread of the implants is
  adequate.
• The decision to fabricate a bar
  over-denture over five implants, rather than a
  fixed detachable restoration, usually relates to
  the patients ability to maintain proper oral
  hygiene.

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Five-Implant Overdenture
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Five-Implant Overdenture
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PROSTHETIC PROTOCOL

• Overdenture abutments were cemented or scrowed
  into the implants.
• Pressure indicating paste was placed on each
  overdenture ball.
• The denture was seated so that the pressure
  indicating paste could mark the exact location of
  the overdenture abutments. Then, a recess was cut
  into the denture at each abutment location
• The resulting depressions in the mucosal aspect
  of the denture were lined with polyvinylsiloxane
  material and seated in the patient's mouth.
• The denture was either lined with a lab-processed
  material or O-rings were used for retention.

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Overdenture abutments were cemented or scrowed
into the implants.
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Pressure indicating paste was placed on each
overdenture ball.
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Then, a recess was cut into the denture at each
abutment location
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lined with polyvinylsiloxane material and seated
in the patient's mouth.
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The denture was either lined with a lab-processed
material or O-rings were used for retention
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• THANK YOU

Thank You!