CHAPTER 13 & 14. Dentistry subjectpdf 2.pdf

IMPLANT-SUPPORTED
FIXEDPROSTHESES
GROUP 2
1

Subperiosteal
Transosteal
Endosteal
IMPLANT TYPES
Subperiosteal Transosteal
IMPLANT TYPES IMPLANT TYPES
Anchor dentures for completely
edentulous patients
}
2

PRINCIPLES OF IMPLANT L
Surgically placed within alveolar or basal bone
Commonly used for treatment of partially edentulous
patients (single or multiple)
Subdivided into:
Blade form (plate form)
a.
Wedge-shaped
i.
Rectangular
ii.
Root form
b.
PRINCIPLES OF IMPLANT LOCATION
ENDOSTEAL
3

Placed in the bone
Immediately project through
mucosa into the oral cavity
ONE-STAGE
IMPLANT TYPES IMPLANT TYPES
TWO-STAGE-
STAGE
Requires two surgical
procedures/surgeries
Implant is placed in bone to the
level of the cortical plate and
the oral mucosa is sutured over
it
a.
Mucosa is reflected from the
superior surface of the implant
b.
4

ENDOSTEAL
First endosteal dental implants to be used
Problems caused by temperature at bone site and immediate
loading
Drawbacks:
Difficulty of preparing precision slots for blade placement
a.
Large circumferential area of the jaw is affected when a
blade fails
b.
ENDOSTEAL
PLATE IMPLANTS
(BLADES)
5

ENDOSTEAL
State-of-the-art implant dentistry
Advantages:
Adaptability to multiple intraoral locations
Uniformly precise implant site preparation
Comparatively low adverse consequences
Made of titanium/ titanium alloy; w/wo hydroxyapatite coating
(highest biofunctionality)
Threaded (straight/tapered)/ Nonthreaded
Grit-blasted/ acid etched
ENDOSTEAL
ROOT-FORM IMPLANTS
6

TREATMENT PLANNING FOR THE IMPLANT PATIENT
7
INDICATIONS FOR IMPLANT PLACEMENT IN
THE PARTIALLY EDENTULOUS PATIENT
CONTRAINDICATIONS
Inability to wear a removable partial
prosthesis or complete denture.
1.
Need for long- span fixed dental prosthesis
with questionable prognosis.
2.
Unfavorable numner & location of potential
natural tooth abutments.
3.
Single tooth loss that would necessitate
preparation of minimally restored teeth for
fixed prosthesis.
4.
Acute illness
1.
Terminal illness
2.
Pregnancy
3.
Uncontrolled metabolic disease
4.
Tumoricidal irradiation of impplant site
5.
Unrealistic patient expectation
6.
Improper patient motivation
7.
Lack of operator experience
8.
Inability to restore with a prosthesis
9.

CLINICAL EVALUATION
8
Begins with a thorough clinical examination
Determines adequate bone structure
a.
Identifies anatomic structure
interference w/ ideal implant placement
b.
Visual inspection
Palpation
Alone, may not be adequate due to dense,
immobile, and fibrous thick overlying soft
tissue
Panoramic view (Best initial film)
Cephalometric film
Reveals bone width (If not revealed on
a panoramic film)
Evaluated in the anterior maxilla &
mandible
CT (Computed Tomography) scans
determine the location of the:
Inferior alveolar canal
Maxillary sinus
RADIOGRAPHIC EVALUATION

DIAGNOSTIC CASTS BONE SOUNDING
9
Used to:
Study the remaining dentition
Evaluate the residual bone
Analyze maxillomandibular
relationships
Helpful for fixture placement
Diagnostic waxing
Resin template
Attempted when:
Results of clinical/ radiographic
examinations are equivocal
a.
Additional information is
needed
b.
Needle is pushed through the tissue
until bone is in contact (under local
anesthesia)
Helps judge soft tissue thickness

Implant should be placed entirely
within bone and away from significant
anatomic structures (e.g., inferior
alveolar canal)
Ideal dimensions: 10 mm vertical bone
and 6 mm horizontal for implant
placement
Ensures 1.0 mm of bone on both lingual
and facial aspects
ANATOMIC LIMITATIONS Minimum distance between implants:
3.0 mm
PRINCIPLES OF IMPLANT LOCATION PRINCIPLES OF IMPLANT LO
10

PRINCIPLES OF IMPLANT L
Adequate space allows for bone viability and proper
oral hygiene
Specific considerations based on anatomic variations:
implant length, diameter, proximity to adjacent
structures, and integration time
Special considerations for different jaw areas: anterior
maxilla, posterior maxilla, anterior mandible, posterior
mandible
11

Common guidelines:
Stay 2.0 mm above the inferior alveolar canal
5.0 mm anterior to the mental foramen
1.0 mm from periodontal ligament of adjacent
teeth
Ridge resorption causes crestal bone thinning and
angulation changes, especially in anterior mandible
and maxilla
PRINCIPLES OF IMPLANT LO
12

ANTERIOR MAXILLA
Evaluate for proximity to nasal cavity
Minimum 1.0 mm of bone should remain between
implant apex and nasal vestibule
Incisive foramen may be near the residual ridge after
maxilla resorption
Implants should be placed slightly off midline, on
either side of the incisive foramen
13

POSTERIOR MAXILLA
Bone density in posterior maxilla is lower than the
mandible, requiring longer integration time and
possibly more implants
Minimum 6 months for implant integration in maxilla
14

POSTERIOR MAXILLA
Bone density in posterior
maxilla is lower than the
mandible, requiring longer
integration time and
possibly more implants
Minimum 6 months for
implant integration in
maxilla
Maxillary sinus close to the edentulous ridge.
15

ANTERIOR MANDIBLE
Generally, straightforward treatment planning with
adequate height and width for implants
Bone quality is excellent, and integration time is shorter
Immediate loading of implants is possible with good initial
stability
In premolar area, ensure implant does not impinge on
inferior dental nerve (minimum 5.0 mm anterior to mental
foramen)
16

Implants should
engage the cortex of
the inferior mandibular
border.
Whenever possible,
implants should
engage two cortical
plates of bone.
ANTERIOR MANDIBLE
17

Inferior alveolar nerve passes through mandibular body
Leave 2.0-mm margin from implant apex to superior aspect of
the inferior alveolar canal
Disregarding this can cause nerve damage and numbness of
lower lip
If implant length is insufficient, consider nerve repositioning, onlay
grafting, or non-implant prosthesis
Implants are usually shorter and do not engage cortical bone
inferiorly
More time may be required for integration due to biomechanical
occlusal forces
POSTERIOR MANDIBLE
18

Short implants (8 to 10 mm) may be necessary due to bone
resorption.
POSTERIOR MANDIBLE
19

Start planning with a restorative dentistry consultation
Implant position affects appearance, contour, and function
Maintain ≥1.0 mm from adjacent teeth for safety and
contouring
Keep ≥3.0 mm between implants for hygiene access
Avoid encroaching on embrasure spaces or facial screw
access
Align implant long axis with central fossa to reduce lateral
forces
Ensure accurate 3D placement (mesiodistal, buccolingual,
superoinferior)
Superoinferior placement critical for emergence profile
Implant platform should be 2.5–3.0 mm apical to emergence
point (esp. anterior esthetic zone)
IMPLANT PLACEMENT
20
RESTORATIVE CONSIDERATIONS RESTORATIVE CONSIDERATI

Implant choice depends on tooth size and restoration
diameter
Example:
Maxillary central incisor: 8.0 mm root → needs 2.5–3.0
mm transition from a 4.0 mm implant
Prevents overcontouring and unnatural appearance
Mandibular incisors often <4.0 mm → require smaller
implants (~3.0 mm)
Molars may need larger implants (5.0–6.0 mm) if bone allows
Restoration size must guide implant selection and
positioning during planning
IMPLANT AND RESTORATION SIZE
21

SINGLE TOOTH IMPLANT
22
Highly challenging due to esthetic
and biomechanical demands
Precise implant placement
minimizes screw loosening and
ensures optimal appearance
Implant design should include an
antirotational feature (e.g., spline or
hexagon)
Critical to address these factors
during the treatment planning stage

SOFT TISSUE CONTOURS
23
Soft tissue framing is crucial for esthetic
outcomes
Achieving a formed papilla between implant
and adjacent teeth can be challenging
Loss of interdental tissue and underlying bone
may prevent ideal papillary contours
Guidelines predict soft tissue contour success
based on interdental bone-to-contact distance:
~5 mm distance: Papilla usually present
~8 mm distance: Papilla unlikely without
soft tissue grafting

Crucial for esthetic outcomes and optimal prosthetic results
Surgical guide templates help ensure correct implant
angulation, emergence profiles, and alignment with the
restoration
Key objectives for partially edentulous patients:
Define embrasures
Position implant within the restoration contour
Align implant long axis with the restoration
Identify cementoenamel junction or soft tissue
emergence
24
URGICAL GUIDE SURGICAL GUIDE SURGICAL GUIDE SURGICAL

Facial veneer templates recommended for anterior implants
to allow clear access and proper angulation
Templates are fabricated from diagnostic waxing, resin, and
vacuum-formed matrix
Radiopaque templates can be made by adding barium
powder
Surgical guide ensures proper placement without affecting
the facial surface or screw access
Maxillary anterior region most critical for template use, but
also beneficial for posterior areas with wide ridges
25
URGICAL GUIDE SURGICAL GUIDE SURGICAL GUIDE SURGICAL

26
MPLANT SURGERY IMPLANT SURGERY IMPLANT SURGERY IMP
Implant surgery is typically done in an ambulatory setting with local anesthesia, though it may take
more time than other procedures, making conscious sedation preferable. Despite patient
expectations, implant placement is less traumatic than tooth extraction. Preoperative education and
conscious sedation can help reduce anxiety. Detailed surgical procedures can be found in current
standard texts.
SURGICAL ACCESS
Incision choice: Should allow tissue retraction for proper implant placement and preserve esthetics
Crestal incision: Recommended when adequate attached tissue and sufficient bone width are
present
Posterior mandible: Incision placed buccally for flap retraction, but risk of dehiscence due to thin
bone
Maxillary anterior zone: Palatal-side incision is effective for better access
Pre-implant preparation: Use a surgical template and smooth uneven or sharp ridge areas before
placement

27
IMPLANT PLACEMENT
Atraumatic site preparation: Use low-speed, high-torque
handpiece with proper irrigation to minimize thermal injury
Step-by-step drilling: Gradually enlarge the site with progressively
larger burs, starting with a small-diameter drill
Surgical template: Guides implant site location and angulation
Final site assessment: Check alignment with a paralleling pin, and
ensure adequate bone for implant positioning
Osseous augmentation: May be needed if bone support is
insufficient
Implant placement:
Non-threaded implants: Tapped into place with a mallet
Threaded implants: Screwed into place, may require self-
tapping for softer maxillary bone
Tension-free closure: Prevents wound dehiscence

28
POST-OPERATIVE EVALUATION
Post-op radiograph: Evaluate implant position relative to
adjacent structures (e.g., sinus, inferior alveolar canal)
Post-surgery care: Mild analgesics and 0.12% chlorhexidine
gluconate rinses for 2 weeks to reduce bacterial growth
Weekly evaluations: Recommended until soft tissue healing is
complete (2-3 weeks)
Denture use: Avoid full/partial dentures for 1 week; then, reduce
resin and use soft liner to prevent injury to implant site

29
IMPLANT UNCOVERING
Uncovering
Performed after complete implant integration (6 months maxilla, 3-4 months
mandible)
Techniques
Tissue punch, crestal incision, or flap repositioning
Abutment Placement
Can use final abutment or interim healing cap
Seating:
Ensure complete seating without gaps, and align antirotational features if
present
Evaluation
Post-operative radiograph to check superstructure-implant interface

PLANT RESTORATIONS IMPLANT RESTORATIONS IMPLANT RES
1. SURGICAL
a. Documented success rate
b. In-office procedure
c. Adaptable to multiple intraoral
locations
d. Precise implant site preparation
e. Reversibility in the event of implant
failure
Osseointegrated implants support screw- or cement-retained prostheses,
offering advantages over conventional restorations. Restoring them involves
multiple components, which may vary by system and can be complex for less
experienced clinicians.
30
ADVANTAGES OF OSSEOUS INTEGRATED IMPLANTS
2. PROSTHETIC
a. Multiple restorative options
b. Versatility of second-stage components
Angle correction
Esthetics
Crown contours
Screw- or cement-retained options
c. Retrievability in the event of prosthodontic
failure

IMPLANT BODY
The dental implant body is the component placed within the
bone during first-stage surgery.
MATERIAL AND DESIGN
May be threaded or nonthreaded root form.
Made of titanium or titanium alloy.
Varying surface roughnesses, with or without hydroxyapatite
coating
31

A B C D
A. Titanium screw.
B. Hydroxyapatite-coated screw.
C.Hydroxyapatite-coated cylinder.
D. Titanium plasma-sprayed cylinder.
32

CLASSIFICATION BY STAGE
One-stage implants:
Project through soft tissue immediately after Stage
I surgery.
Two-stage implants:
Covered with soft tissue after Stage I.
33
LANT RESTORATIONS IMPLANT RESTORATIONS IMPLANT REST

When a tall healing screw or cap is placed on a two-
stage implant to project it through the tissue at the time
of placement,
This is referred to as:
“Using a two-stage implant with a one-stage
protocol.”
34
ANT RESTORATIONS IMPLANT RESTORATIONS IMPLANT RESTO

During the healing phase after first-
stage surgery, a screw is normally
placed in the superior aspect of the
fixture.
It is usually low in profile to facilitate
the suturing of soft tissue in the two-
stage implant or to minimize loading in
the one-stage implant.
HEALING SCREW
35

At second-stage surgery, it is removed and replaced by
subsequent components.
Some systems make the screw slightly larger than the implant
diameter to prevent bone overgrowth on the implant edge.
Ensure complete seating of the screw to prevent bone growth
between the screw and the implant.
Removing bone may damage the superior implant surface
and affect fit of components.
HEALING SCREW
(FUNCTIONS AND PRECAUTIONS)
36

Dome-shaped screws placed
after second-stage surgery
before prosthesis insertion.
Length: 2 to 10 mm, projecting
through soft tissue into oral
cavity.
May screw into fixture or onto
the abutment
INTERIM ABUTMENT
A B
37
MPLANT RESTORATIONS IMPLANT RESTORATIONS IMPLANT RE

Made of titanium or titanium alloy.
Stabilizes gingival margin in esthetic
zones.
Healing time: 2 weeks (non-esthetic
areas), 3–5 weeks (esthetic zones).
INTERIM ABUTMENT
38
LANT RESTORATIONS IMPLANT RESTORATIONS IMPLANT REST

Screwed directly into the implant to support prosthesis.
Forms: for screw- or cement-retained restorations.
Made of titanium/titanium alloy, lengths from 1 to 10 mm.
ABUTMENTS
39
MPLANT RESTORATIONS IMPLANT RESTORATIONS IMPLANT R

In nonesthetic areas: 1–2 mm of titanium should penetrate
tissue for hygiene.
ABUTMENTS
(ESTHETIC & HYGIENE CONSIDERATIONS)
A B
40
LANT RESTORATIONS IMPLANT RESTORATIONS IMPLANT RES

In esthetic areas: porcelain carried subgingivally.
Anti-rotational abutments require two components.
ABUTMENTS
(ESTHETIC & HYGIENE CONSIDERATIONS)
A
B
C D
41

Angled abutments correct divergent implants.
Tapered/wide-base abutments restore larger
teeth.
Nonsegmented crowns (UCLA) bypass
abutments; useful in <2 mm tissue.
All-ceramic components for esthetic zones.
ABUTMENTS
(SPECIALIZED TYPES)
42

ABUTMENTS
(SPECIALIZED TYPES)
43

ABUTMENTS
(SELECTION CRITERIA)
Based on vertical distance, sulcular
depth, and esthetics.
Posterior teeth: margin at/below
gingival crest.
Anterior maxillary crowns: 2–3 mm
subgingival porcelain.
Use probing to assess subgingival
space before/after healing.
Abutment length affects restoration
contours
44

IMPRESSION COPINGS
Transfer implant/abutment location to lab cast.
Types: fixture vs abutment; transfer (indirect) vs pickup (direct).
Radiograph confirms complete engagement.
IMPRESSION COPINGS
(TRANSFER & PICKUP)
Transfer coping stays in place after impression, then attached
to analog.
Flat-sided copings orient implant thread and antirotational
features.
Angled abutments must be in same position as lab fabrication.
45
ANT RESTORATIONS IMPLANT RESTORATIONS IMPLANT REST

TYPES OF IMPRESSION
COPINGS
A. One-piece coping (screws onto abutment):
used if abutment won’t be changed on the cast.
B. Two-piece coping (transfer/closed tray):
attaches to fixture; used if abutment needs to be
changed; flat side for angle correction.
C. Two-piece coping (pickup/open tray): used to
orient antirotational features or for divergent
implants.
46

IMPRESSION COPINGS
Two-piece pickup uses square coping,
long guide pin, open-top tray.
Prevents rotation; guide pin accessed
for unscrewing after setting.
Preferred for divergent implants.
Transfer technique used when space is
limited.
Radiograph always needed before
impression, especially with
antirotational features.
A
B
47
T RESTORATIONS IMPLANT RESTORATIONS IMPLANT RESTOR

IMPLANT ANALOGS
Represent top of
implant or abutment in
lab cast
Fixture analogs and
abutment analogs
screw into impression
coping.
A B
48

IMPLANT ANALOGS
(SOFT TISSUE REPLICATION)
Use elastomer (e.g.,
Permadyne*) before
pouring stone for soft
tissue modeling.
Helps in easy removal
and prevents stone
damage.
A B
C D
49

IMPLANT ANALOGS
(APPLICATION)
Implant body analog: allows abutment changes in lab.
Flat-sided coping: defers angulation correction until lab
stage.
If confident with abutment choice, use abutment analog to
simplify.
No need for soft tissue cast with supragingival abutment
margin.
50
PLANT RESTORATIONS IMPLANT RESTORATIONS IMPLANT RE

WAXING SLEEVES
Attached to abutment in lab; become part of prosthesis.
In nonsegmented crowns, attached directly to implant analog.
Known as UCLA abutments.
WAXING SLEEVES
(MATERIALS & ADJUSTMENT)
Types: burn-out plastic patterns, precious metals, or hybrid.
Metal ensures machined fit; plastic cast surface may be retooled.
Available in various heights; tall ones can be shortened.
Modern versions combine gold alloy and plastic
51

PROSTHESIS-RETAINING SCREWS
Penetrate fixed
restoration to secure to
abutment.
Tightened with
screwdriver.
Used in nonsegmented
crowns.
52

PROSTHESIS-RETAINING SCREWS
Materials: titanium, titanium
alloy, or gold alloy.
Long or short variants.
Short screws countersunk in
occlusal surface.
Must be covered by resilient
material (e.g., gutta-percha,
cotton, silicone).
Final seal with composite resin
53

IMPLANT RESTORATIVE O
IMPLANT RESTORATIVE OPTIONS
Provide significant benefits for partially edentulous patients,
especially when adjacent natural teeth are not ideal for
support.
In cases where greater occlusal forces are anticipated—such as
in the posterior region or in patients with parafunctional habits
—placing more implants is advisable.
Conversely, fewer implants may suffice when lighter forces are
expected, like in areas opposing complete dentures or in
anterior regions.
54
DISTAL-EXTENSION IMPLANT SUPPORTED
RESTORATION

Include placing multiple implants between
remaining natural teeth to support a fully implant-
supported restoration, or combining one or two
implants with natural teeth.
Telescopic copings- when implants are connected
to natural teeth and enhances prosthesis
retrievability.
55
LONG EDENTULOUS SPAN RESTORATION

Metal-resin fixed dental prosthesis AKA “Hybrid
Prostheses” : for cases requiring soft and hard tissue
reconstruction and are preferred due to their ability
to replicate soft tissue esthetics more accurately than
traditional metal-ceramic restorations.
Pink Porcelain: For smaller soft tissue defects used to
achieve a natural appearance
56
LONG EDENTULOUS SPAN RESTORATION

An attractive option for the patient and dentist but requires careful implant
placement and precise control of all prosthetic components.
Indications in the following situations:
Intact dentition
a.
A dentition with spaces that would be more difficult to treat with
conventional fixed prosthodontics
b.
Distally missing teeth when cantilevers or partial removable dental
prostheses are not indicated.
c.
A prosthesis that needs to closely mimic the missing natural tooth
d.
57
SINGLE-TOOTH IMPLANT RESTORATION

Esthetics
1.
Anti-rotation: to avoid prosthetic component loosening
2.
Simplicity: to minimize the amount of components used
3.
Accessibility: to maintain optimum oral health
4.
Variability: to allow the clinician to control the height, diameter, and
angulation of the implant restoration
5.
The best soft tissue esthetics is still generally achieved when interdental papillae
are present before the surgery. If soft tissue contours are deficient before
surgery, the patient should expect some compromise in the final soft tissue
result.
58
REQUIREMENTS

59
FIXED RESTORATION IN THE COMPLETELY EDENTULOUS ARCH
Complete metal-resin fixed dental prosthesis:
Cast alloy framework with processed denture
resin and teeth. It is typically supported by
minimum of five implants in the mandible and
six in the maxilla. One major determining
factor for selecting this option is the amount
of bone and soft tissue that has been lost. For
patients who have had moderate bone loss,
the prosthesis restores both bone and soft
tissue contours.
Metal-ceramic fixed dental prosthesis:
Requires a minimum of five implants in the
mandible and six in the maxilla. It can be
made esthetically pleasing only if bone loss is
minimal and is best suited for patients who
have recently (within 5 years) lost their
natural teeth. For patients with severe bone
loss, there is probably only one option: a
removable restoration.
2 IMPLANT OPTIONS:

60
The amount of bone resorption dictates the treatment options for an edentulous
patient.
A. Minimal resorption may allow metal-ceramic restorations.
B. Moderate resorption may necessitate resin-to-metal restorations.
C. Severe resorption necessitates only implant-supported overdentures for optimum
esthetic results.

61
Attached to the implants at all times. Therefore,
patients experience psychologic benefit of having a
restoration that closely resembles their original natural
teeth.
Movement within the system is minimized, and the
components tend to wear out less quickly.
Since prosthesis is screw retained, the dentist can
remove it, allowing access for cleaning and repairs.
FIXED RESTORATION (METAL RESIN/METAL-CERAMIC)
(MAIN ADVANTAGES)

Implants must be precisely placed, especially in the maxillary
anterior esthetic. Implants placed in embrasure spaces can lead
to disastrous esthetic results and can impede access for
hygiene.
With a metal-resin prosthesis, the clinician must decide between
leaving enough space for hygiene access and minimizing space
for optimum esthetics.
Some patients may be concerned by the amount of metal shown
in a metal-resin prosthesis.
62
FIXED RESTORATION (METAL RESIN/METAL-CERAMIC)
(POTENTIAL DISADVANTAGES)

FEAUTURE CEMENT-RETAINED SCREW-RETAINED
Retrievability
Difficult (especially with permanent
cement)
Easy
Esthetics Superior (no screw access hole) May be compromised by access hole
Maintenance More complex Simple and convenient
Chair Time May be longer Generally shorter
63
CEMENT-RETAINED VS. SCREW RETAINED IMPLANT CROWNS

FEAUTURE CEMENT-RETAINED SCREW-RETAINED
Cost Often more economical initially May cost more upfront, less later
Implant Angulation Compensation Yes Limited; requires ideal placement
Risk of Loosening Present
Present, especially if not torqued
properly
Use in Small Teeth Preferred Less Ideal
64
CEMENT-RETAINED VS. SCREW RETAINED IMPLANT CROWNS

OCCLUSION
Bone resorption around implants can result from
premature or excessive loading, especially from
lateral forces. Implants handle vertical forces better,
so restorations should minimize lateral stress, ensure
proper occlusion, and evenly distribute forces. Ideal
implant placement involves one implant per tooth or
two for every three teeth in dense bone. Cantilevers
should be kept short to prevent overloading.
CONNECTING IMPLANTS TO NATURAL TEETH
Implants are rigid, while natural teeth move slightly,
creating stress when connected. This mismatch can
lead to screw loosening, cement failure, or implant
damage. If connection is necessary, use multiple
abutments or semiprecision attachments, though a
fully implant-supported prosthesis is preferred.
IMPLANT AND FRAMEWORK FIT
A poor framework fit can create harmful forces at the
bone-implant interface. Even if gaps appear closed
when all screws are tightened, stress may still be
present. Passive fit should be verified using the one-
screw test. If misfit is detected, the framework must
be sectioned, soldered, and reassessed, with a relation
record taken.
CAD/CAM ABUTMENTS AND FRAMEWORKS
CAD/CAM allows for precise, custom-made ceramic or
titanium abutments and frameworks. These offer
better fit and accuracy than traditional methods,
improving the long-term success of implants.
65
BIOMECHANICAL FACTORS AFFECTING LONG-TERM IMPLANT
SUCCESS

MAINTENANCE AND COMPLICATIONS
MAINTENANCE
Ensure that the patient receives thorough instructions and
should be reinforced by a session with the dental hygienist
during recall visits.
To eradicate microbial populations affecting the prosthesis
*At least every 3-months during 1 year of implant
st
Oral Hygiene
Implant Mobility
Bleeding
Framework fit and occlusion
MAINTENANCE AND CO
66

COMPLICATIONS
Bone Loss
Primary complication; any loss exceeding 0.2 mm per year is cause for concern.
ONE YEAR FOLLOW-UP
POST-PLACEMENT
The restorative dentist should pay
particular attention to :
Fit of the prosthesis
Access for hygiene
Presence of excessive occlusal
forces
MAINTENANCE AND COMPLICATIONS MAINTENANCE AND CO
67

Prosthetic Failure
Fracture of the implant components or of the prosthesis, usually due to fatigue
from biomechanical overload
MAINTENANCE AND COMPLICATIONS MAINTENANCE AND CO
68

Implant-supported prostheses, involving cylindrical osseous
integrated fixtures placed by a two-stage surgical technique,
should be considered in the treatment of any partially
edentulous patient.
It requires the same attention to detail and careful
planning as conventional fixed prosthodontics.
69
SUMMARY SUMMARY SUMMARY SUMMARY SUMMARY

TISSUEMANAGEMENTAND
IMPRESSIONMAKING
GROUP 2
70

In impression making, there are many aspects to consider before the
procedure in order to have a successful impression.
These include proper moisture control to prevent voids, and in cases
where margins are subgingival, a displacement is made to allow
proper material flow.
Poor saliva control and tissue management can result in inaccurate
impressions or even permanent tissue damage.
INTRODUCTION
INTRODUCTION
71

PREREQUISITES
PREREQUISITES
The health of surrounding soft tissues must be carefully prepared and
reevaluated before impression making.
TISSUE HEALTH
72

PREREQUISITES
PREREQUISITES
Depending on the location of the preparations in the dental arch, several
techniques can be used to create the necessary dry field of operation.
SALIVA CONTROL
Rubber dam
Expa-syl (gingival retraction)
Svedopter or Speejector (flange-type evacuator)
Absorbent card
Disposable Hygoformic Aspirator (tongue displacement)
73

PREREQUISITES
PREREQUISITES
A commonly needed procedure to obtain adequate access to
the prepared tooth to expose all necessary surfaces, both
prepared and not prepared.
DISPLACEMENT OF GINGIVAL TISSUES
Can be achieved through :
Mechanical means
Chemical means
Surgical means
74

DISPLACEMENT OF GINGIVAL TISSUES DISPLACEMENT OF GING
DISPLACEMENT CORD
By placing a nonimpregnated cord and leaving it in place for a sufficient
amount of time, enlargement of the gingival sulcus can be obtained (A).
Better sulcus enlargement can be achieved with a chemically impregnated
cord or by dipping the cord in an astringent (B), such as Hemodent, which
shrinks the gingival tissue. After the cord is removed, the sulcus closes quickly
in which the impression should be taken immediately.
A B 75

STEP-BY-STEP PROCEDURE
A B
Isolate the tooth with cotton rolls, place saliva
ejectors, and dry the area.
Cut enough cord to encircle the tooth; avoid over-
drying to prevent sensitivity (A).
Soak the cord in astringent (B), squeeze out excess,
and keep moist to avoid tissue damage.
Twist nonbraided cord for easier placement, if used.
Loop cord around the tooth and gently insert into the
sulcus with a suitable instrument (C,D).
A B
C D
DISPLACEMENT OF GING
76

DISPLACEMENT OF GINGIVAL TISSUES DISPLACEMENT OF GING
EVALUATION
Initial assessment of cord placement can be a useful indicator of the amount
of displacement accomplished.
If the result is acceptable, a second cord (saturated with astringent) is quickly
inserted to maintain the displacement and is removed after several minutes.
The first cord is remained during impression making (Double-cord technique).
It is better to delay impression making and focus more on improving tissue
health rather than to attempt under adverse conditions.
A B 77

HEMORRHAGE CONTROL WITH AN INFUSOR SYRINGE
E
E
Fill the syringe with ferric sulfate (A) and attach the
infusor tip (B).
Rub the tip on the bleeding area for ~30 seconds while
slowly injecting more solution (C).
Rinse with air-water spray, dry gently, and check if
bleeding has stopped; repeat if needed and place
cord (D).
Before removing the cord, moisten it to prevent
bleeding, dry the area, and take the impression (E).
In a case of hemorrhage:
A B
C D
E
78

A B
DISPLACEMENT PASTE
Some dentists advocate displacement paste as an alternative to cord, showing
good hemostasis and less discomfort. However, less tissue displacement is
achieved which may make die trimming more problematic.
79

A B
ELECTROSURGERY
In cases for minor tissue removal before impression making,
an electrosurgery unit may be used.
In removing the epithelial lining of the gingival sulcus, it improves access for a
subgingival crown margin and effectively controls postsurgical hemorrhage.
However, there is potential for gingival tissue recession after treatment.
80

A B
SOFT TISSUE LASER
Soft tissue lasers have also been advocated as a means of removing a
controlled amount of tissue before impression making, and are also useful for
tissue contouring procedures.
81

MATERIALS SCIENCE
A B
MATERIALS SCIE
82
MATERIALS SCIENCE
ELASTIC IMPRESSION MATERIALS
There is an extensive variety of materials for making a precision
negative mold of soft and hard tissues. In order of their historical
development, they are the following:
Reversible hydrocolloid.
Polysulfide polymer.
Condensation silicone.
Polyether.
Addition silicone.

MATERIAL ADVANTAGES DISADVANTAGES RECOMMENDED USE PRECAUTIONS
Irreversible
Hydrocolloid (Alginate)
Fast, Easy, Cheap
Less accurate, Poor
surface detail, Not for
definitive cast
Study models,
Preliminary
impressions, Diagnostic
cast
Pour immediately
Reversible Hydrocolloid
(Agar)
Water-loving, Longer
work time, Cheap
material
Weak, Unstable,
Needs special
equipment
Impressions for
crowns and bridges
(specific cases),
Duplicating models
Pour immediately,
Use carefully with
prepared teeth
Polysulfide (Polymer) Strong
Messy, Smelly, Long
set time, Fair
stability
Most impressions Pour within 1 hour
A B 83

Condensation Silicone Pleasant, Fast
Water-repelling, Poor
wetting, Less stable
Most impressions
Pour immediately,
Avoid bubbles when
pouring
Addition Silicone (PVS)
Very stable,
Pleasant, Fast set,
Automix
Water-repelling
(some), may release
gas, imbibes
moisture
Most impressions
Handle carefully,
may need delay
pour, avoid bubbles
Polyether
Very stable,
Accurate, Fast set,
Automix
Very stiff, Absorbs
water, Short work
time
Most impressions Handle carefully
A B 84
MATERIAL ADVANTAGES DISADVANTAGES RECOMMENDED
USE PRECAUTIONS

MATERIALS SCIENCE
A B
MATERIALS SCIE
85
MATERIALS SCIENCE
IMPRESSION TRAY
(TRAY SELECTION AND IMPRESSION MATERIALS)
The choice of impression material directly influences tray
selection.
Reversible Hydrocolloids (Agar):
Require special water-cooled trays.
Irreversible Hydrocolloids & Elastomers:
Often used with prefabricated (stock) trays.
Common for uncomplicated fixed prosthodontics.

MATERIALS SCIENCE
A B
MATERIALS SCIE
86
MATERIALS SCIENCE
IMPRESSION TRAY
(TRAY DESIGN AND RETENTION)
Tray rigidity is crucial to reduce distortion.
Design must control impression material thickness.
Retention features:
Perforations
Rim locks
Adhesives

MATERIALS SCIENCE
A B
MATERIALS SCIE
87
MATERIALS SCIENCE
IMPRESSION TRAY
(CUSTOM TRAYS)
Fabricated individually using diagnostic casts.
Offer advantages over stock trays:
Better fit
Improved stability
Enhanced accuracy
ADHESIVES – APPLICATION TIPS
Apply well in advance to allow drying.
Should be thinly applied (to ensure solvent evaporation).
May feel slightly tacky, which is acceptable.

MATERIALS SCIENCE
A B
MATERIALS SCIE
88
MATERIALS SCIENCE
PAINT-ON VS. SPRAY-ON ADHESIVES
Paint-on adhesives:
Provide better retention for polyvinylsiloxane (PVS)
materials.
Spray-on adhesives:
Show less retention on both autopolymerizing and
photopolymerizing tray materials.

89
A custom tray improves the accuracy50 of an elastomeric impression by limiting the
volume of the material, thus reducing two sources of error: stresses during removal
and thermal contraction.
Custom trays can be made from autopolymerizing acrylic resin, thermoplastic resin, or
photopolymerized resins.
CUSTOM TRAY FABRICATION CUSTOM TRAY FABRICATION CUST

90
ARMAMENTARIUM
Baseplate wax
0.025-mm (0.001-inch)
tinfoil
Scalpel
Scissors
Waxing instrument
CUSTOM TRAY FABRICATION CUSTOM TRAY FABRICATION CUST

91
STEP-BY-STEP PROCEDURE: AUTOPOLYMERIZING RESIN
Using a pencil, mark the border of the tray on the diagnostic cast approximately 5 mm apically
to the crest of the free gingiva.
1.
Adapt a wax or other suitable spacer to the diagnostic cast. Two layers of baseplate wax result
in a combined thickness of approximately 2.5 mm.
2.
Soften the wax by carefully heating it over a Bunsen burner or in hot water.
3.
After the second sheet of wax has been applied, trim it back until the pencil line is just visible.
4.
Apply a layer of tin foil over the wax to prevent it from contaminating the inside of the tray.
5.
Mix autopolymerizing acrylic resin according to the manufacturer’s recommendations.
6.
After the resin is mixed, set it aside until it is doughy.
7.
Gently adapt the resin to the cast. A handle made from the excess resin can be attached at this
time.
8.
After the material has polymerized, remove it from the cast and trim it with an acrylic trimming
bur where the indentation made by the wax ledge is visible.
9.
10. If necessary, fill defects in the stops with additional resin, wetting the set tray material with
monomer to ensure a good bond.
CUSTOM TRAY FABRICATION CUSTOM TRAY FABRICATION CUSTO

92
Note: Follow steps 1—5 as for the autopolymerizing technique.
6. Remove photopolymerized tray material sheets from their light-proof packaging, and
adapt them to the relieved cast.
7. Shape and attach a handle by molding excess material. Blend into the tray material.
A paper clip can be used to support the handle material by adapting the material
around it.
8. Position the cast in the curing unit for approximately 2 minutes. Remove from the
curing unit, separate the tray from the cast, and remove the softened wax spacer and
the aluminum barrier.
9. Return the cast to the curing unit and cure in accordance with the time recommended
by the manufacturer. Remove the tray and scrub it clean under running water.
10. Clean the tray, and trim as for the autopolymerizing resin tray.
STEP-BY-STEP PROCEDURE: PHOTOPOLYMERIZED RESIN

93
EVALUATION
The completed custom tray needs to be rigid, with a consistent
thickness of 2 to 3 mm. It should extend about 3 to 5 mm cervical to
the gingival margins and should be shaped to allow muscle
attachments. It should be stable on the cast with stops that can
maintain an impression thickness of 2 or 3 mm. The tray must be
smooth, with no sharp edges. Finally, the handle should be sturdy and
shaped to fit between the patient’s lips. To avoid distortion from
continued polymerization of the resin,56 the tray should be made at
least 9 hours before its use.

94
When elastomeric impressions are made, an assistant is essential, unless
the AutoMix technique is used.
MPRESSION MAKING IMPRESSION MAKING IMPRESSION MAKING
ELASTOMERIC MATERIALS
STEP-BY-STEP PROCEDURE:HEAVY BODY—LIGHT BODY COMBINATION
1. Evaluate the custom tray in the patient’s mouth to verify its fit. Correct the tray
as needed.
2. Apply tray adhesive to extend a few millimeters onto the external surface of
the tray.
3. Isolate the abutment teeth and place gingival displacement cord in the sulcus.
4. On separate pads (one for the tray and one for the syringe material), disperse
equal amounts of base and accelerator.

95
5. Blend the two pastes thoroughly. Initially, the spatula is kept somewhat vertical
during mixing; this position is changed gradually to be more horizontal as the two
pastes become better incorporated.
6. Load the syringe. This can be done by holding the barrel vertically, pushing it through
the mix, and then angling and sliding it sideways over the mixing pad.
7. Remove the displacement cord and gently dry the preparation with compressed air.
8. Place the tip of the syringe nozzle so that it touches the margin and inject the material
slowly.
9. Express additional material to any edentulous spaces, lingual concavities of the
anterior teeth (which are important for guidance), and occlusal surfaces of the posterior
teeth (which are important for obtaining an accurate articulation).
10. Seat the tray. It must remain immobile while the material undergoes polymerization
(6 to 12 minutes, depending on the material).
IMPRESSION MAKING IMPRESSION MAKING IMPRESSION MAKIN

96
PRESSION MAKING IMPRESSION MAKING IMPRESSION MAKING
SINGLE MIX TECHNIQUE AUTO MIX TECHNIQUE MACHINE MIXING TECHNIQUE
The same steps are performed
for the single-mix technique as
for the heavy body—light body
technique; however, as the name
indicates, only one mix is used to
load the syringe and fill the tray.
Most single-mix materials tend to
produce a slightly higher
viscosity mix with a slightly
shorter working time.
Most impression materials come
in cartridges with disposable
mixing tips, used with a caulking
gun-like device. This system
allows automatic mixing and
direct application, reducing voids
by eliminating hand mixing.
An alternative method for
improving impression mixing is to
use a machine mixer. This system
is convenient and produces void-
free impressions.

97
The impression must be inspected for accuracy when it is removed.
If bubbles or voids appear in the margin, the impression must be
discarded. An intact, uninterrupted cuff of impression material
should be present beyond every margin. Streaks of base or catalyst
material indicate improper mixing and may render an impression
useless. If the impression passes all these tests, it can then be
disinfected and poured to obtain a die and definitive cast.
IMPRESSION MAKING IMPRESSION MAKING IMPRESSION MAKIN
EVALUATION

98
Reversible hydrocolloid impression material requires
a special conditioning unit which is made up of
three thermostatically controlled water baths:
REVERSIBLE HYDROCOLLOID REVERSIBLE HYDROCOLLOID
Liquefaction – 100°C
Storage – 65°C
Tempering – 40°C

99
Choose the largest water-cooled impression tray that fits
comfortably for better accuracy.
1.
Place prefabricated stops on the posterior part of the tray to
prevent overseating and enhance retention.
2.
Displace gingival tissues for adequate access.
3.
Fill tray with heavy-bodied material, add wash material to key
areas, then place tray in tempering bath.
4.
Remove the cord from the sulcus and rinse with warm water.
5.

100
6. Remove tray from tempering bath, seat it in the mouth, and
start the flow of room-temperature water.
7. Hold the tray firmly in place until the impression material
sets.
8. Quickly remove tray, rinse, disinfect, and evaluate; potassium
sulfate may be used to improve stone properties.
9. Pour impression immediately using type IV or V stone, or
store in an oil-based solution if delayed.

101
EVALUATION
A reversible hydrocolloid impression is evaluated in the
same manner as polysulfide polymer. However, the
translucency of the material may make small imperfections
difficult to detect. If doubt exists, it may be expedient to
make a new impression, because this does not require
additional tissue displacement and can be easily
accomplished.

102
SED-MOUTH IMPRESSION TECHNIQUE
The closed-mouth impression technique, also known as the
dual-arch or triple tray technique, is commonly used for
single-unit restorations. It captures the prepared tooth,
adjacent teeth, and opposing teeth in maximum
intercuspation, using a high-viscosity polyether or
polyvinylsiloxane material in a mesh-supported tray. This
allows for an accurate impression and occlusal record,
although it does not record eccentric jaw relationships,
which must be adjusted during restoration delivery.
CLOSED-MOUTH IMPRESSIO

103
Select and evaluate a closed-mouth tray; ensure the patient can close fully
into maximal intercuspation without interference.
1.
Apply adhesive to the tray walls and load both sides with high-viscosity
elastomeric impression material.
2.
Remove the retraction cord and use a syringe to apply impression material
onto critical areas.
3.
Place the loaded tray into position and have the patient close properly;
check the opposite side to confirm maximum intercuspation.
4.
Once the impression material has set, assist the patient in opening by
applying pressure to the tray or material on the non-prepared side.
5.

104
The impression is evaluated for accuracy and detail
Ensure that the patient has not closed into the sides or
distal bar of the tray.
EVALUATION

105
SPECIAL CONSIDERATIONS SPECIAL CONSIDERATIONS SPEC
Certain modifications of the basic impression technique are sometimes
needed, particularly for making impressions with additional retention
features such as pinholes and post space.
Elastomeric impression materials are strong enough to reproduce a
pinhole without tearing. However, to avoid bubbles, they must be
introduced carefully into the pinhole with a lentulo or cement tub.With
reversible hydrocolloid, a special nylon bristle must be used for the
impression.
PIN-RETAINED RESTORATIONS

106
Apply a separating medium to the pinholes and displace
the tissue as usual.
Mix light-bodied impression material and reserve a
small amount for the pinholes.
CEMENT TUBE
Use the tube to fill each pinhole with material, ensuring
no air is trapped by using an explorer

107
Ensure the handpiece rotates clockwise before picking up impression material
with the lentulo.
Insert material into pinholes in a spiraling motion, rotating slowly along the
pinhole walls.
Increase speed while withdrawing the lentulo to avoid pulling material out.
PREFABRICATED PLASTIC PIN
For reversible hydrocolloid impressions, use trimmed plastic bristles to register
pinholes, adjusting length so they don’t touch the tray.
Apply separating medium to the pinhole before placing the bristle and finishing
the impression.
LENTULO

108
DISINFECTION
Impressions should be treated as contaminated and
must be disinfected immediately after removal. Rinse
with tap water, dry with an air syringe, and disinfect
using appropriate agents like glutaraldehyde or
iodophor sprays. Material compatibility is important—
polyether or hydrophilic silicones should be sprayed and
sealed in a plastic bag, not soaked, to prevent distortion.
Proper disinfection prevents cross-infection and does
not affect impression accuracy.
DISINFECTION DISINFECTION DISINFECTI

109
DISINFECTION
RECOMMENDED DISINFECTION METHOD BY IMPRESSION MATERIAL
DISINFECTION DISINFECTION DISINFECTION

110
An impression captures the prepared tooth and
surrounding structures, requiring moisture control and
healthy soft tissues. A custom acrylic resin tray is
recommended for elastomeric materials. Impressions
should be disinfected immediately, with polysulfide
poured within an hour and polyether or addition silicone
stored longer. Accurate impressions are essential for well-
fitting restorations, especially for pin-retained ones.
SUMMARY SUMMARY SUMMARY SUMMARY SUMMARY SUM

THANKYOUEVERYONE!
THANKYOUEVERYONE!
111

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