Titanium chamber was surgically inserted into the tibia of a rabbit. Result revealed that there was a direct strong bone anchorage of titanium
Elasticity of bone makes contact and connection a functional unit in which contact between implant and bone is maintained.
Diagram showing a wedge of cortical bone and spongy bone. Osteoblast and osteon.
Weak, poorly organised and mineralised Strong well porganised and minralaised Fnal attachment of lamellar str to allow attachment of fibres ligaments and tendons
Orientation of collagen fibrils
Remodelling cycle = 17 weeks in humans
Remodelling includes : Localized changes in individual osteons or trabeculae Turnover, hypertrophy, atrophy or reorientation
Extensive work by the Swedish orthopaedic surgeon P.-I. Brånemark led to the discovery that commercially pure titanium (CPTi), when placed in a suitably prepared site in the bone, could become fixed in place due to a close bond that developed between the two (Fig. 2.1), a phenomenon that he later described as osseointegration
Y did fibrous osseointegration lead to infection
Primary bone healing Secondary bone healing The basic science, in brief: Primary bone healing is lead by the formation of a so-called cutting cone (consisting of osteoclasts at the front of the cone to remove bone and trailing osteoblasts to lay down new bone) across the gaps to form a secondary osteon. Secondary bone healing involves the classical stages of injury, hemorrhage inflammation, primary soft callus formation, callus mineralization, and callus remodeling. This method of bone healing closely resembles endochondral ossification (which involves a cartilage template being replaced by bone).
This accumalation of pp on the surface will increase the platelet adhesion
Osseointegration is a biological concept which involves the incorporation of a foreign body to the living bone (host) with fixation and stability when subjected to functional loads. In order for dental implant osseointegration to occur, there must be an adherence of the cells to the surface of the biomaterial. The implant surface characteristics can modulate the adsorption of proteins, lipids, sugar, and ions present in the tissue fluids. Attachment to a surface is a critical first step in cell response because it determine which cells will populate the surface and how many (Boyan et al., 2001). In vitro tests with osteoblastic cells showed that when cell adhesion occurs, the cells change shape and spread. In this phase, reorganization of cytoskeletal proteins occurs. At points of contact between cells and biomaterials there is an exchange of information between cells and the extracellular matrix, leading to activation of specific genes and remodeling. As the chemical composition of biomaterial induces different reactions of the cells, the surface properties of biomaterials induce different reaction mechanisms (Anselme & Bigerelle, 2005). Both the morphology and the surface roughness of biomaterials influence proliferation, differentiation, extracellular matrix synthesis, production of local factors and even cell shape
Cytokines and growth fCTORES
the fact that osteoblast cells adhere and spread more easily on rough surfaces than on smooth ones. Add to surface treatment of implants
Implant stability depends on direct mechanical connection between implant surface and the surrounding bone and can be divided into primary, secondary and tertiary stability. The stability obtained immediately after insertion of a dental implant is called primary stability. The stability obtained after osseointegration is named secondary stability. The tertiary stability is the maintenance of osseointegration.
During machining of titanium, absorption of O2 molecules occurs. After about 10 nanoseconds, the molecules dissociate and a monolayer of atomic oxygen is deposited. This oxygen reacts with titanium to form a titanium oxide film with a thickness between 50 and 100 Å (5 a 10 nm).
Bone can be formed on the adjacent bone surfaces in a phenomenon called distance osteogenesis, or on the implant surface itself in a phenomenon called contact osteogenesis [23,24]. In the case of distance osteogenesis, osteogenesis occurs from the bone toward the implant as the bone surfaces provide a population of osteogenic cells that deposit a new matrix that approaches the implant. In the case of contact osteogenesis, osteogenesis occurs in a direction away from the implant as osteogenic cells are recruited to the implant surface and begin secreting bone matrix. While both these processes are likely to occur with implants, their relative significance may depend on the specific type of implant and its surface characteristics.
migration of differentiating osteogenic cells to the proposed site. These cells are derived at bone remodeling sites from undifferentiated peri-vascular connective tissue cells.
Differentiating osteogenic cells, which reach the implant surface initially, secrete a collagen-free organic matrix that provides nucleation sites for calcium phosphate mineralization. FOLLOWED BY CRYSTAL GROWTH.
because it is the cement line, secreted as a non-collagenous mineralized matrix by differentiating osteoblasts, that invaginates, interdigitates and interlocks with the demineralized collageous matrix left by the resorbing osteoclast and thus it plays a critical physical role in the establishment of the interface of new bone and old bone.
cascade of de novo bone formation (this term is explained in ) at solid surfaces as a four-stage process (Fig. 1C) comprising: the adsorption of non-collagenous bone proteins to the solid surface; the initiation of mineralization by the adsorbed proteins (Figs. 1D and E); continued mineralization due to crystal growth; and finally the assembly of a collagenous matrix overlying the interfacial matrix with mineralization within the collagenous matrix.
When osteoclasts resorb bone, which is known to be a two phase process of both the dissolution of the inorganic matrix and enzymatic degradation of the organic components, the result is the creation of a demineralized bone matrix which becomes the recipient surface for new bone formation.
morphological feature of the resorbed bone matrix is important because it presents a surface of three-dimensional complexity, at the sub-micron scale range, into which the matrix of the cement line can be deposited to form an anchoring mechanism of new bone to old. Thus, in normal bone remodeling, the resorption surface of old bone provides a highly topographically complex surface into which new bone matrix will be deposited, and with which the latter can interdigitate and interlock.
The thickness of the oxide layer increases with time and incorporates ions of Ca, P and S from the physiological environment. The surface properties of implants, such as morphology, roughness, thickness of the oxide layer, impurity level and types of oxide depend on the treatment to which the material was submitted. It is important to remember that contact between the implant and the body established through a titanium oxide film; there is no contact between metallic titanium and the body.
This term refers to calcium phospate and bioactive glasses which undergo reactions that lead to chemical bonding.
OSSEOCOALESCENCE=The term applies to surface reactive materials, such as calcium phosphates and bioactive glasses, which undergo reactions that lead to chemical bonding between bone and biomaterial. An example of qualitative evidence for chemical bonding is when fracture lines propagate through either the implant or the tissue but not along the interface
Biocompatibility is attributed to the stable oxide layer, primarily titanium dioxide (TiO2), that spontaneously forms when titanium is exposed to oxygen.
Calciumphosphate hydroxyapatite, Al2O3, Tricalcium phosphate) Develop a chemical bond of a cohesive nature Makeup the entire implant Applied in the form of coating onto the metallic core.
Reverse buttress Thread pitch of implant Crest – The outermost surface joining the two sides of the thread. Root – The innermost surface joining the two sides of the thread. Helix angle – The angle formed by a point on the side and the plane perpendicular to the axis of the screw thread. Pitch – The distance from a point on one thread to a corresponding point on the adjacent thread, measured parallel to the axis. Lead – The axial distance that the implant advances in one complete turn.
Buttress threads are the strongest thread form for a given size because of their larger base cross-section, and because they minimize shear forces in a manner similar to square threads. They combine excellent primary stability with the best features of both V- and square-thread forms. V , TRAPEZOID, SQUARE AND BUTTRESS
In the past, implants coated with hydroxyapatite (HA) were widely used. They are no longer used due to the huge number of periimplantitis observed. However, HA-coated implants had a larger amount of bone overlying the surface compared to uncoated implants. In these implants the number of gaps between the HA coating and bone was lower and the formation of mineralized nodules was more pronounced.
REFER INTECH FACTORS AFFECTING SUCCESS OF DENTAL IMPLANTS
During machining of titanium, absorption of O2 molecules occurs. After about 10 nanoseconds, the molecules dissociate and a monolayer of atomic oxygen is deposited. This oxygen reacts with titanium to form a titanium oxide film with a thickness between 50 and 100 Å (5 a 10 nm). It is important to remember that contact between the implant and the body established through a titanium oxide film; there is no contact between metallic titanium and the body.
Clinical results indicate that when the dental implant insertion torque is higher than 40 N.cm, the success rate increases
Countersinking done to To reduce and minimize the bacterial infection. ii. To prevent the apical migration of oral epithelium along the body of implant. iii. To reduce and minimize the risk of early implant loading during bone remodelling.
The marginal bone around the implant crestal region is usually a significant indicator of implant health
Of course, conventional radiographics only monitor the mesial or distal aspect of bone loss around the implant
Presence of deep pockets ws not accompanied by accelerated marginal bone loss
Probing not only measures pocket depth, but also reveals tissue consistency, bleeding, and the presence of exudate
It is of benefit to probe and establish a baseline measurement after the initial soft tissue healing around the permucosal aspect of the implant. Increases in this baseline measurement over time most often represents marginal bone loss.
Implant quality scale ; osseointegration, success criteria and basic guides
Methods of evaluation
Fibro – osseous
• The concept of osseointegration was developed
and the term was coined by Dr. Per-Ingvar
Branemark, Professor at the institute for Applied
Biotechnology, University of Goteborg, Sweden
“The apparent direct attachment or connection of osseous
tissue to an inert, alloplastic material without intervening
connective tissue”. - GPT 8
Structurally oriented definition
“Direct structural and functional connection between the
ordered, living bone and the surface of load carrying
- Branemark and associates (1977)
Direct anchorage of an implant by the formation of
bone directly on the surface of an implant without
any intervening layer of fibrous tissue.
- Albrektson and Johnson (2001)
Ankylosis of the implant bone interface.“Functional
ankylosis” -Schroeder and colleagues 1976
“It is a process where by clinically asymptomatic rigid fixation
of alloplastic material is achieved and maintained in bone
during functional loading”
- Zarb and T Albrektson 1991
Biomechanically oriented definition
“Attachment resistant to shear as well as tensile forces”
- Steinmann et al (1986).
Bone can be classified as
• Compact bone
• Spongy bone
Depending on age, developmental age, localization and
function, bone consists of three tissue types that differ in
collagen fibril arrangement and mineral content.
• Formed by the osteoprogenitor cells in the vicinity
of blood vessels during prenatal development
,growth and healing .
• Forms 30-50 µm /day
• High cellular osseous tissue
• Low mineral content
• More pliable than mature lamellar bone
• Capable of stabilizing an unloaded implant,woven
bone lacks the strength to resist functional loads .
• Principle load-bearing tissue
• Predominant component of mature cortical and
• Forms relatively slow (< 1.0µm/day)
• Have highly organized matrix, and are densely
• Orientation of the collagen fibrils differs from one
layer to another .
• Found in the area of ligament and tendon attachment
along the bone-forming surfaces.
• Striation are extension of sharpey’s fibers composed of
collagen bundles from adjacent connective tissue that
insert directly into the bone
• It is formed adjacent to the periodontal ligament of
physiologically drifting teeth.
• A surface specific activity that produces a net change in
the size and/or shape of bone .
• An uncoupled process, meaning that cell activation(A)
proceeds independently to formation(F) or resorption(R)
• Generalized change in overall dimension of a bone’s
cortex or spongiosa
• Modelling is a fundamental mechanism of growth ,
atrophy and reorientation.
• It is the turnover or internal restructuring of previously
existing bone .
• Coupled tissue level phenomenon
Bone to implant interface
There are two basic theories
In 1986, the American Academy of Implant Dentistry (AAID)
“Tissue-to-implant contact with healthy dense collagenous
tissue between the implant and bone”
Presence of connective tissue between the implant and
Collagen fibers functions similarly to Sharpey’s fibers
found in natural dentition.
The fibers are arranged irregularly, parallel to the implant
body, when forces are applied they are not transmitted
through the fibers
Collagen fibers at the interface - peri-implant membrane
with an osteogenic effect.
Collagen fibers invest the implant, originating at the
trabeculae of cancellous bone on one side, weaving
around the implant, and reinserting into a trabeculae on
the other side.
It was felt that, this membrane gave a cushion effect and
acted as similar as periodontal membrane in natural
Failure of fibro-osseous theory
No real evidence
Forces are not transmitted through the fibers -
remodeling was not expected
Forces applied resulted in widening fibrous
encapsulation, inflammatory reactions, and gradual bone
resorption there by leading to failure.
Natural teeth Implant
Oblique and horizontal
group of fibers
Uniform distribution of
load (Shock absorber)
Difficult to transmit
Failure : Inability to carry adequate loads -
American Academy of Implant Dentistry (AAID) defined it as
"contact established without interposition of non-bone tissue
between normal remodeled bone and an implant entailing a
sustained transfer and distribution of load from the implant
to and within the bone tissue"
Mechanism of Osseointegration
• Healing process may be primary bone healing or
secondary bone healing.
• In primary bone healing, there is well organized bone
formation with minimal granulation tissue formation -
• Secondary bone healing may have granulation tissue
formation and infection at the site, prolonging healing
period. Fibrocartilage is sometimes formed instead of
bone - undesirable
Blood between the
fixture and bone
Mechanism of osseointegration
Phase Timing Specific occurrence
Day 1-10 Adsorption of plasma proteins
Platelet aggregation and
Clotting cascade activation
Specific cellular inflammatory
Phase Timing Specific occurrence
Day 3 - 42 Neovascularization
activation of cells.
Production of immature
Phase Timing Specific occurrence
Remodeling of the
immature bone matrix with
coupled resorption and
deposition of bone.
Bone remodeling in
response to implant loading
Bone tissue response
• Distance Osteogenesis
A gradual process of bone healing inward from the edge
of the osteotomy toward the implant. Bone does not
grow directly on the implant surface.
• Contact Osteogenesis
The direct migration of bone-building cells through
the clot matrix to the implant surface. Bone is quickly
formed directly on the implant surface.
Mechanism of integration: (Davies - 1998)
Contact osteogenesis :
Early phases of osteogenic cell migration
De novo bone formation
Bone remodeling at discrete sites.
“Osteoconduction” refers to the migration of differentiating
osteogenic cells to the proposed site.
Migration of the connective tissue cells will occur through
the fibrin that forms during clot resolution.
The migration of cells through a temporary matrix such as
fibrin - retraction of the fibrin scaffold.
De novo bone formation
Differentiating osteogenic cells, which reach the implant
surface initially, secrete a collagen-free organic matrix that
provides nucleation sites for calcium phosphate
Noncollagenous bone proteins - Osteopontin and bone
Bone bonding in de novo bone formation
Bonding of de novo bone will occur by the fusion, or
micromechanical interlocking of the biologic cement line
matrix with the surface reactive layer
During the long-term phase of peri-implant healing, it is
only through those remodeling osteons that actually
impinge on the implant surface that de novo bone
formation will occur at these specific sites on the implant
Stages of Osseointegration
According to Misch there are two stages in
osseointegration, each stage been again divided into
two substages. They are:
Stage 1: Woven callus (0-6 weeks)
Stage 2: Lamellar compaction (6-18 weeks)
Stage 3: Interface remodeling (6-18 weeks)
Stage 4: Compact maturation (18-54 weeks)
Stage 1: Woven callus
0-6 weeks of implantation.
Woven bone is formed at implant site.
Primitive type of bone tissue and characterized
Random, felt-like orientation of collagen
Numerous irregularly shaped osteocytes
Relatively low mineral density
Stage 2: Lamellar compaction
6th week of implantation and continues till 18th week.
The woven callus matures as it is replaced by lamellar
This stage helps in achieving sufficient strength for
Stage 3: Interface remodeling
This stage begins at the same time when woven callus is
completing lamellar compaction.
During this stage callus starts to resorb, and remodeling
of devitalized interface begins.
The interface remodeling helps in establishing a viable
interface between the implant and original bone.
Stage 4: Compact bone maturation
This occurs form 18th week of implantation and continues
till the 54th week.
During this stage compact bone matures by series of
modeling and remodeling processes.
The callus volume is decreased and interface remodeling
Six different factors known to be important for the
establishment of a reliable, long-term osseous anchorage
of an implanted device
State of the host bed
Surgical technique and
Chemical interaction determined – properties of surface
Commercially pure (c.p.) Titanium and Titanium alloy (Ti
Documented long term function
Covered with adherent, self- repairing oxide layer
Excellent resistance to corrosion – high dielectric
Load bearing capacity
Cobalt chrome molybdenum alloys
Ceramics - calcium phosphate hydroxyapatite (HA) and
various types of aluminium oxides
Biocompatible - insufficient documentation and very less
clinical trials - less commonly used.
Characteristics of Reactions of
Biotolerant Implants separated from
adjacent bone by a soft tissue
layer along most of the
Stainless steels: CoCrMo
and CoCrMoNi alloys
Bioinert Direct contact to bony tissue
Alumina ceramics, zirconia
tantalum, niobium, carbon.
Bioactive Bonding to bony tissue:
containing glasses, glass-
Grouping of hard tissue replacement materials according to
their compatibility to bony tissue
Implant Design (Macrostructure)
Threaded or screw design implants
More functional area for stress distribution
than the cylindrical implants.
Minimal - <0.2 mm/year bone loss
Press fit root form implants depend on
coating or surface condition to provide
microscopic retention and bonding to the
•Tendency for slippage
•Bonding is required
•No slippage tendency
•No bonding is required
Functional surface area per unit length of implant may be
modified by the three thread geometry parameters
• Thread shape
• Thread pitch
• Thread depth
Grooves on the threads of all implants and on the collars,
Increase surface area
Increase area for bone-to-implant contact
Implant Surface (Microstructure,Surface Topography)
“The extent of bone implant interface is positively
correlated with an increasing roughness of the
Greater bone to implant contact at histological level
Micro irregularities - cellular adhesion.
High surface energy - improved cellular attachment.
• Roughness parameter (Sa)
0.04 –0.4 m - smooth
0.5 – 1.0 m – minimally rough
1.0 –2.0 m – moderately rough
2.0 m – rough
• Wennerberg (1996) – stated that moderately rough implants
developed the best bone fixation.
Smooth surface < 0.2 m will – soft tissue no bone cell
adhesion clinical failure.
Moderately rough surface more bone in contact with implant
State of the host bed
Ideal host bed
Healthy and with an adequate bone stock
Undesirable host bed states for implantation
Ridge height resorption
Implant bed - Bone Quality
According to Lekholm and Zarb,1985
• Quality I
composed of homogenous compact
bone found in the lower anterior
• Quality II
Thick layer of cortical bone surrounding
dense trabecular bone found in the lower
Thin layer of cortical bone surrounding
trabecular bone – upper anterior and
lower posterior region
Very thin layer of cortical bone surrounding
a core of low-density trabecular bone
- very soft bone found in the
upper anterior and posterior
Branemark system (5 year documentation)
Mandible – 95% success
Maxilla – 85-90% success
According to Branemark and Misch
D1 and D2 bone initial stability / better osseointegration
D3 and D4 poor prognosis
D1 bone – least risk
D4 bone - most at risk
Selection of implant
D1 and D2 – conventional threaded implants
D3 and D4 – HA coated or Titanium plasma coated implants
Promote regenerative type of the bone healing rather than
reparative type of the bone healing.
The critical time/ temperature - bone tissue necrosis - 47°
for one minute.
Bone cutting speed of less than 2000 rpm
Tapping at a speed of 15 rpm with irrigation
Using sharp drills
The optimal torque threshold – 35 N/cm.
Implant should gently engage the bone in order to avoid
too much pressure at the bone interface which could
Surgical skill / technical excellence
Progressive or two stage loading
Branemark et al to accomplish osseointegration
considered the following prerequisites
Countersinking the implant below the crestal bone
Obtaining and maintaining a soft tissue covering over
the implant for 3 to 6 months
Maintaining a non loaded implant environment for 3 to
- Two-stage surgical protocol
- One-stage surgical protocol
1. Immediate occlusal loading (placed within 48 hours)
2. Immediate non-occlusal loading (in single-tooth or
3. Early loading (within two months)
Type 2 (late-onset) diabetes: This is especially the
case where this is not well controlled
Treatment by an operator with limited surgical
Patients who were smokers at the time of implant
surgery had a significantly higher implant failure rate
(23.08%) than non-smokers (13.33%)
Short implants and implant placement in the maxilla
were additional independent risk factors for implant
DeLuca S, Habsha E, Zarb GA. The effect of smoking on
osseointegrated dental implants. Part I: implant survival. Int J
Absence of discomfort
Improved emotional and psychological wellbeing
Harvard success criteria
The dental implant must provide functional service
for 5 years in 75% of cases
Bone loss no greater than 33% of vertical length of implant
Gingival inflammation amenable to treatment
Mobility of less than 1mm in any direction
Absence of symptoms of infection
Absence of damage to surrounding structure
Healthy connective tissues
Possible criteria for success
Marginal bone loss
Damage to adjacent teeth
Violation of maxillary sinus , mandibular canal
or floor of nasal cavity
Length of service
Condition for application of criteria
Only osseointegrated implants should be
evaluated with these criteria.
The criteria apply to individual endosseous
At the time of testing, the implants must have
been under a functional load.
Implants that are beneath the mucosa and in a
state of health in relation to the surrounding
bone should preferably not be included in the
evaluations but reported as complications.
Complications of an iatrogenic nature that are
not attributable to a problem with material or
design should be considered separately when
computing the percentage of success
Revised criteria - Albrektsson
Individual implant is immobile clinically
No evidence of peri-implant radiolucency is
present as assessed on an undistorted
Mean vertical bone loss is less than 0.2 mm
annually after the first year of service.
No persistent pain, discomfort, or infection is
attributable to the implant.
Implant design does not preclude placement of
a crown or prosthesis with an appearance that is
satisfactory to the patient and dentist.
By these criteria, a success rate of 85% at the
end of a 5-year observation period and 80% at
the end of a 10 year period are minimum levels
Drago et al
Moy et al –
Bass et al –
conventional tooth-supported FDPs of 93.8%
cantilever FDPs of 91.4%
solely implant supported FDPs of 95.2%
combined tooth-implant-supported FDPs of 95.5%
implant supported SCs of 94.5%
FDP vs Implants
After 10 years of function –
89.2% -conventional FDPs
80.3% -cantilever FDPs
86.7%- implant-supported FDPs
77.8% - combined tooth-implant-supported FDPs
89.4% - implant-supported SCs
Technical complications were (fractures of the veneer
material, abutment or screw loosening and loss of
Stability is a requisite characteristic of
Initial stability is a function of the
Implant design and
During the osseointegration healing and
maturation process , the initial stability changes
with increases in bone- to –implant contact and
Histological sections (10 microns sections)
Histomorphometric – To know the percentage of bone
Transmission electron microscopy
By using Torque gauges
Tapping with a metallic instruments
Ringing sound- osseointegrated.
Dull sound - fibrous integration.
Reliable method to determine implant stability
Emg driven and electronically controlled
tapping head that hammers an object at a
rate of 4 times/sec
Response to striking is measured by a small
accelerometer present in head
Signals converted to periotest value
Depends on damping characteristic of tissues
surrounding teeth or implant
Developed by Aoki and Hirakawa
Mech is similar to periotest
Microphone used as receiver and signals
transferred is processed by FFT for analysis
Dental mobility checker
Non invasive can be performed at any stage of
Bite wing-measure crestal bone level
1.5 mm of CBL can be expected in the Ist year
of loading with 0.1 mm of subsequent annual
Difficult for clinician to detect changes at 0.1mm
Can be measured when central ray of x-ray is
perfectly ll with the structure of interest
Excellent method to assess health of natural teeth
In implants little diagnostic value unless accompanied by
signs & symptoms
Stable implants pocket depth- 2-6mm
Indicate bone loss but not necessarily disease
Sulcus depth greater than 5-6 mm-risk of anaerobic
Suggested by James, modified by Misch
Misch CE, Perel ML, Wang HL, et al. Implant success, survival, and failure: The
International Congress of Oral Implantologists (ICOI) Pisa Consens Conference.
Implant Dent 2008;17:5-15.
Implant quality of health scale
No pain or tenderness upon function
Less than 2.0 mm crestal bone loss from initial
No history of exudate
Group I (Success)
No pain on function
Crestal bone loss – 2 to 4 mm
No history of transient exudate
Prognosis good to very good
Slight to moderate peri-implantitis
Sensitivity on function
Radiographic bone loss > 4 mm (<1/2 of implant
No mobility (IM-O)
Probing depth >7 mm
May have exudates history
Uncontrolled progressive bone loss;
50% bone loss
surgically removed/ exfoliated
(clinical or absolute failure)
0 Absence of clinical mobility with 500g in any
1 Slight detectable horizontal movement
2 Moderate visible horizontal mobility up to
3 Sever horizontal movement greater than 0.5
4 Visible moderate to sever horizontal and any
visible vertical movement
Cutting Torque resistance analysis (CRA)
Reverse Torque test (RTV)
Resonance Frequency analysis (RFA)
Johansson and strid and improved by Friberg et
Energy required for a current fed electric motor
in cutting off a unit volume of bone during
surgery is measured.
Energy is correlated with bone density which
influences the implant stability
Cutting Torque resistance analysis (CRA)
Torque guage-in drilling unit measures the
insertion torque in Ncm, gives idea about the
Gives more objective assessment than clinician
a. Detect bone density
b. Identify bone density during surgery
c. Can be used in daily practice
a. can only be used during surgery
b. longitudinal data cannot be collected to assess
bone quality changes after implant placement
Measures the ‘critical’ torque threshold where
bone-implant contact (BIC) was destroyed
Removal Torque value (RTV)-indirect
measurement of BIC/clinical osseointegration
Reverse Torque test (RTV)
Ranges from 45-48 Ncm
RTV >20 Ncm accepted as criteria for
Varies depending on bone quality & quantity
a. RTV only provide information as to “all or
b. Mainly used in experiments
Non invasive method that measures implant stability
& bone density at various time points
RFA utilizes a small L-shaped transducer that is
tightened to implant or abutment
Resonance Frequency analysis (RFA)
Transducer comprises of 2 piezoceramic
One for vibration, and other serves as a receptor
for the signal
Resonance peaks from the received signal
indicates the first RF of the measured object
Earlier hertz was used as measurement unit
now implant stability quotient (ISQ)
RF values ranging from 3500-8500 Hz
translated into ISQ of 0-100
RFA can only give information regarding success
cannot provide information with respect to survival
ISQ is fairly reliable when implant has achieved
osseointegration & the B-I interface is rigid.
ISQ tends to fluctuate when the interface is not rigid
Misch CE. Contemporary implant dentistry, 3rd edition,
Mosby Elsevier publication, St Louis, 2008, pp:27, 70,
Hobkirk JA, Watson RM, Searson LJ. Introducing dental
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dental implants,osseo integration and evaluation of osseointegration success criteria of implant quality scale