PARTS OF A DENTAL IMPLANT.docx

7/27/2019 PARTS OF A DENTAL IMPLANT.docx

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PARTS OF A DENTAL IMPLANT INCLUDE:

1- CROWN

2- ABUTMENT

3- IMPLANT BODY

4- IMPRESSION COPING

5- ANALOGUE OR IMPLANT REPLICA

6- RETENTIVE ANCHORS

7- BAR RETAINER

THE PARTS OF A DENTAL IMPLANT ARE AS FOLLOWS:

1. CROWN Definition: The part of a tooth projecting from the gum.

Fig : Crowns

Crowns are the top part of a restoration and are the part that we see in the mouth. They replicate

the original teeth to provide a biting surface and aesthetic appearance. (Fig.18). They are hand

made by the technician. The supporting substructure for the crown may be hand-made or

machined (onsite or offsite).

Material Used: Porcelains (metal supported or metal free) or metal (normally gold)


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2. ABUTMENTDefinition: The lateral supporting structure of a bridge, arch, etc. The point

of junction between such a support and the thing supported.(Fig.19)

Fig.19: Abutment

An abutment provides support for the crown (or several crowns i.e. a bridge). It is also the

interface between the crown and the implant. Rotation (twist) is controlled by lugs shaped on the

abutments stem. These lugs restrict the abutments rotational placement by setting incremental

steps.

Materials Used: Titanium.

3. IMPLANT BODY

Definition: An insert (tissue, a substance, a device, etc.) into the body.

Fig.: Implant Body

Implant body may be further divided into (Fig 20)

1. Crest module

2. Implant body

3. Implant apex


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An implant body provides the anchor or foundation for a restoration. It is screwed into the bone

of the jaw providing a fixed platform on which an abutment can be screwed.

Bone tissue can grow around the implant regenerating and strengthening the jaw reducing the

bone loss which occurs when natural teeth are lost

Materials Used: Titanium.

4. IMPRESSION COPING

Fig.: Impression Coping

Impression copings are used by the dentist to replicate the position of the implant in the patients

mouth. The dentist screws the impression coping to the real implant and then, using a specific

impression technique, takes an impression of the dentition. (Fig 21) The impression technique

can be open or closed:

Open tray technique allows the dentist to remove the impression complete with impression

coping(s) from the patients mouth by allowing external access to the copings retaining screw(s)

i.e. the impression coping(s) remain fixed in the impression material. The dentist is then required

to add the analogue(s) prior to dispatching to the lab.

Closed tray technique requires that the dentist first removes the impression the patients mouth

then unscrews the impression coping(s) to remove them from the implant. The impression

coping(s) are then placed back into position by the dentist in the impression material and the

analogues are added prior to despatch.

Materials Used: Titanium, plastic, and anodized aluminium


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5. ANALOGUE OR IMPLANT REPLICA

Fig .: Analogue

Analogues are used by laboratory technicians to replicate implants and their position in a

patients mouth. A model of the patients dentition is cast using an impression. The analogue,

screwed onto the impression coping, is set into the plaster model during casting. (Fig. 22)

They provide an exact fixed reference platform (a replica of the position of the implant) from

which the technician can place and shape the abutment and build the crown or bridge.

Materials Used: Stainless steel (sometimes brass)

6. RETENTIVE ANCHORS

Fig .23: Retentive anchors

Retentive anchors come in various types of design: Ball Abutment (with retaining clip),

Magnetic Abutment (with retaining magnet) and Tower Abutment (which comes with a retaining

clip). All come in two main parts: The shaped abutment part and the female which c lips over it

known as a Matrix.(Fig. 23)


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Once the anchor abutments are screwed into the implants, they provide support for a full or a

partial denture (which are clipped on). This provides a very stable platform and prevents

unwanted movement of the prosthesis.

Materials Used: Titanium and gold (with plastic matrices or magnetic material)

7. BAR RETAINERS

Fig .24: Bar retainers

Constructed by laboratory technicians, bar retainers mount directly onto implants . A clip

mechanism then secures a denture to the screw retained bar.(Fig. 24)

There are two well known types, Dolder and Hader. These bars provide a strong support option

for retaining dentures. They may be mounted on several different manufacturers implant

systems.

Materials Used: Titanium or gold (clips are plastic or brass)

Requisites of an ideal implant restorative material

It should be stable in the oral environment and should not

undergo corrosion.

It should fit passively over the implant abutment.

It should be esthetic.

It should not induce undue stresses in the implant or the bone.

It should be biocompatible and should not induce any

allergenic reaction.

It should be easy to fabricate and handle.


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It should be easy to maintain.

It should be cost-effective.

The physical, mechanical, chemical and electrical properties of the basic material components

must always be fully evaluated for any biomaterial application, as these properties provide key

inputs into the biomechanical and biologic analysis of function.

The materials used for dental implants can be classified according to their biological nature as

follows:

Biotolerant:Biotolerant materials are those that are not necessarily rejected when implanted into

the living tissue, but are surrounded by a fibrous layer in the form of capsule.

Bioinert:These allow close apposition of bone on their surface, leading to contact osteogenesis.

Bioactive:These materials also allow the formation of new bone onto their surface, but ion

exchange with host tissue leads to the formation of a chemical bond along the interface (bonding

osteogenesis)

Biodynamic

Activity

METALS CERAMICS POLYMERS AND

COMPOSITES

Biotolerant Gold

Co-Cr alloys

Stainless Steel

Zirconium

Niobium

Polyethylene

Polyamide

Polymethylmethacrylate

Polytetrafluoroethylene

Polyurethane


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Tantalum

Bioinert Commercially

Pure Ti

Ti alloy(Ti-6AI-

4V)

Aluminium Oxide

Zirconium Oxide

Bioactive Hydroxyapatite

Tricalcium phosphate

Fluroapatite

Bioglass

Carbon-silicon

Flowchart (3): classification of materials used for dental implants

1.METALS

The metals currently used are:

a) Stainless steel

It has high strength and ductility. The surface is passivated to increase biocorrosion resistance

It is used in wrought and heat treated condition.


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Precautions: It is contraindicated in patients sensitive to nickel. As it is susceptible to crevice

and pitting corrosion, so care has to be taken to preserve passivated surface. It has galvanic

potential, so avoid contact with dissimilar metal e.g. Base metal or noble metal bridge.

b) Cobalt Chromium-Molybdenum Alloy

It has high modulus (stiffness), low ductility, outstanding resistance to corrosion, excellent

biocompatibility. Its commonly used for fabrication of custom design (e.g. Subperiosteal

frames)

Precautions: A proper fabrication techniques should be used as composition is critical. It has

poor ductility, so bending should be avoided.

c) Titanium and Titanium Aluminium / Vanadium alloy

Pure Titanium (Commercially pure titanium CpTi) has become material of choice because of

its predictable behaviour with the oral tissues and environment. It has food corrosion resistance

due to passivating effect. Oxide layer forms on cut surface within a millisecond, thus it is self

healing. It has a low density i.e 4-5 g/cm2 , high strength to weight ratio, low stiffness as

compared to stainless, yet 5 to 10 times greater than living bone.

Precautions: Proper design should be used to distribute stresses properly. It releases titanium

into blood and saliva, however side effects have not been seen yet.

Metal with surface coatings

This includes a titanium implant that is coated with a thin layer of a calcium phosphate ceramic.

It can also be plasma sprayed.

Advantages:


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The tricalcium phosphate or hydroxyapatite is rich in calcium and phosphorous. This produces a

bioactive surface which promotes bone growth and forms a direct bone between the implant and

the bone.

d)Titanium and Ti-6al-4v

This reactive group of metals and alloys form tenacious oxides in air or oxygenated solutions.

This passivated surface minimizes the bio-corrosion phenomenon. In situations where the

implant would be placed within a closely fitting receptor site in bone, areas scratched or abraded

during placement would re-passivate in vivo.

The strength values for wrought soft and ductile metallurgic condition are approximately 1.5

times greater than the strength of compact bone. In most designs where the bulk dimensions and

shapes are simple strength of this magnitude is adequate.

Titanium shows relatively low modulus of elasticity and tensile strength when compared with

most other alloys. Yet its modulus of elasticity is 5 times greater than that of the compact bone,

and this property places emphasis on the importance of design in the proper distribution of

mechanical stress transfer.

Precautions: Sharp corners or thin sections must be avoided for regions loaded under tension or

shear conditions

e) Iron Chromium Nickel Based Alloys

This alloy as with Ti systems is used most often in wrought and heat treated metallurgic

conditions, which results in a high strength and high ductility alloy. The ramus blade, ramus

frame, stabilizer fins and some mucosal insert systems have been made from the iron based

alloy.


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Precautions: Because this alloy contains nickel as major elements, use in patients allergic or

hypersensitive to nickel should be avoided. Iron based alloys have galvanic potentials and

corrosion characteristics that could result in concerns about galvanic coupling and bio-corrosion

if interconnected with Titanium, Cobalt, Zirconium or Carbon implant biomaterials.

f) Cobalt and Iron Alloys

The alloys of Cobalt & Iron exhibit oxides of chromium under normal implant surface finishing

conditions after acid or electro-chemical passivation. These chromium oxides as with Titanium

alloys result in significant reduction in chemical activity & environmental iron transfer.

In the absence of surface damage, the chromium oxide on stainless steel biomaterials have

shown excellent resistance to breakdown & multiple examples of tissue & host compatibility

have been shown for implants removed after long term implantation.

Precautions: if stainless steel implant surfaces are mechanically altered during implantation or if

the construct induces an interface that is subjected to biomechanical fretting, the iron alloy will

biodegrade.

g) Other Metals and Alloys

Tantalum, Platinum, Iridium, Gold, Palladium and alloys of these metals have been used.More

recently devices made from Zirconium, Hafnium and Tungsten have been evaluated.

Precautions: Gold, Platinum and Palladium are metals of relatively low strength which places

limits on implant design. But still Gold is used because of nobility and availability.

2. CERAMICS

Ceramics are inert materials and have excellent biocompatibility


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Based on their interaction with bone there are two types:

a. Bioactive e.g. Hydroxy apatite and Bioglass

b. Bioinert e.g. Aluminum oxide

a) Ceramics and Carbon

Ceramics are inorganic non metallic, non polymeric materials manufactured by compacting and

sintering at elevated temperatures. Because of their inertness to biodegradation, high strength,

physical characteristics such as color and minimal thermal and electrical conductivity, and a

wide range material specific elastic properties they are in use. Ceramics have been used in bulk

forms and more recently as coatings on metals and alloys.

Precautions: The low ductility or inherent brittleness has resulted in limitations:

b) Alumina, Titanium & Zirconium Oxides

High ceramics from aluminum, titanium and zirconium oxides have been used for root form,

endosteal plate form and pin type dental implants. The compressive, tensile and bending strength

exceed the strength of the compact bone by 3-5 times. These properties combined with high

moduli of elasticity and especially with fatigue and fracture strength have resulted in specialized

design requirements.

The Aluminium, Titanium and Zirconium oxide ceramics have a clear white, cream or light gray

color which is beneficial for applications in anterior root form devices.

In early studies of dental and orthopedic devices in laboratory animals and humans ceramics

have exhibited direct interphases with bone similar to an Osseo integrated condition with

Titanium.


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Precautions: One series of root form and plate form devices used during the 1970s resulted in

intra oral fractures after several years of function. The fractures were initiated by fatigue cycling

where biomechanical stresses were along regions of localized bending and tensile loading.

c) Bioactive and Biodegradable Ceramics Based on Calcium Phosphate

The calcium phosphate ceramics used in dental reconstructive surgery include a wide range of

implant types and thereby a wide range of clinical implications. The laboratory and clinical

results for calcium phosphate particulates were most promising and led to expansions for implant

application.

Calcium aluminates, sodium lithium inert glasses with calcium phosphate and glass ceramics

provide a wide range of properties and have found extended applications.

Precautions: In general these classes of bio-ceramics have lower strength, hardness and

modulus of elasticity than the more chemically inert forms previously discussed.

d) Carbon & Carbon Silicon Compounds

Carbon compounds are often classified under ceramics because of their chemical inertness &

absence of ductility, however they are conductors of heat & electricity. Ceramic & carbonate

substances continue to be used as coatings on metallic & ceramic materials.

They show tissue attachment and provide Opportunities for the attachment of active bio-

molecules/synthetic compound.

Precautions: They show lack of mechanical strength properties

e) Hydroxy Apatite


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In addition to bulk, aluminum oxide biomaterials, calcium phosphate based ceramic or ceramic

like coatings have been added to Titanium & Cobalt alloy substrates to enhance tissue

integration. These coatings for the most part are applied by plasma spraying small size particles

of crystalline hydroxyapatite ceramic powders.43

Surface roughening by particulate blasting can be achieved by different media. Sandblasting

provides irregular, rough surface of 10. Titanium implants maybe etched with a solution of

Nitric acid and Hydrochloric acid. The acids very rapidly attack metals other than Titanium &

these processes are electrochemical in nature.

Precautions: Surface roughening is quite a sensitive procedure and requires much care and

precision.

3. POLYMERS & COMPOSITES

It can be designed to match tissue properties, can be anisotropic with relation to mechanical

characteristics, can be coated for attachment to tissues, can be fabricated at relatively low cost.

a)Polymers

In general, polymers have low strength & elastic moduli and higher elongations to fracture

compared with other classes of biomaterials. They are thermal & electrical insulators and are

relatively resistant to bio degradation.44

Polymers have been fabricated in porous and solid forms for tissue attachment, replacement,

augmentation & as coatings for force transfer to soft & hard tissue region. Cold flow


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characteristics, creep & fatigue strengths are relatively low for some classes of polymers. e.g:

Polymethylmethacrylate. In contrast some are extremely tough and fatigue cycle resistant.

e.g: Polytetrafluoroethylene. The indications for Polytetrafluoroethylene have grown

exponentially in the last decade because of the development of membranes for guided tissue

regeneration technique.

b)Composites

Most of the inert polymers have been combined with particulate or fibers of carbon, Aluminum

oxide, Hydroxyapatite & glass ceramics. In some cases, bio degradable polymers such as Poly

Vinyl Alcohol, Poly Lactides or Glycolides, Cyanoacralates or other Hydra table forms have

been combined with bio degradable CaPO4 particulate or fibers. These are intended as structural

scaffolds, plates, screws or other such applications.

TYPES OF IMPLANTS

1.BASED ON THE LOCATION

a) Subperiosteal (fig 31)

In this design, the implant body lies over the bony ridge.

It has decreased long-term success rate because of increased chances of dislodgement

and complex in their design.

The Subperiosteal design currently in use for orthodontics is ONPLANT


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Onplant developed by Block and Hoffman in 1995 consists of circular disc 8-10mm in

diameter with a provision for abutments in center,through which orthodontist carry

tooth movements against implants

Fig 31: Subperiosteal implants

b) Transosseous(fig 32)

The implant body penetrates the mandible completely.

It is not widely used because of possible damage of the

Infra bony soft tissue structures like the nerves and vessels.


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Fig - 32: Transosseous implants

c) Endosseous implants

These implants are partially submerged and anchored within bone.

It is most popular and most widely used one.

Fig 33-endosseous implants

d) Denture Enhancing Intramucosal Implant

Intramucosal inserts differ in form, concept, and function from the other modalities. They aremushroom-shaped titanium projections that are attached to the tissue surface of a partial or totalremovable denture in the maxilla[14] and plug into prepared soft-tissue receptor sites in the gingivato provide additional retention and stability. Thus, they provide support for a prosthesis but do notprovide abutments. They are used in the treatment of patients for whom endosteal orsubperi osteal implants are not deemed to be practical or desirable.Intramucosal inserts do not come into contact with bone, so the mode of tissue integration is not


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osteointegration, osteopreservation, or periosteal integration. Rather, the receptor sites in thetissue into which the inserts seat become lined with tough, keratinized epithelium. In this sense,seated intramucosal inserts are external to the body. Only one appointment is required for theplacement of intramucosal inserts.For reasons that are described in detail in Chapter 20 , intramucosal inserts are best used in themaxilla. Because of complicated biomechanics, more acute alveolar ridge angles, a wider arrayof applied forces, and insufficient gingival thickness, placement of intramucosal inserts in themandible is not recommended. Figs. 2-31 and 2-32 show radiographs of typical mainstream

intramucosal insert cases in the maxilla.


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e) Osseousimplants

These are placed in dense bone such as zygoma, body, ramus and palatal area.


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2. BASED ON THE CONFIGURATION DESIG

A )Root form implants are designed to resemble the shape of a natural tooth root. They usually arecircular in cross section. Root forms can be threaded, smooth, stepped, parallel-sided or tapered,

with or without a coating, with or without grooves or a vent, and can be joined to a wide varietyof components for retention of a prosthesis.As a rule, root forms must achieve osteointegration to succeed. Therefore, they are placed in anafunctional state during healing until they are osteointegrated. Semi-submerged implant healingcollars are then removed, or submerged implants are surgically exposed for the attachment ofcomponents for the retention of a fixed or removable prosthesis. Thus, most root forms are twostageimplants. Stage one is submersion or semi-submersion to permit afunctional healing (, and stage two isthe attachment of an abutment or retention mechanismSemi-submersion of root forms obviates the need for two surgical interventions, which representsan important improvement in the modality in terms of technique-permissiveness. Root formprotocols require separate treatment steps for insertion and abutment or retention mechanism

attachment whether the healing protocol calls for submersion or semi-submersion.

root

a)Screw Type Implant

Tramonte introduced a stress resistant drive screw implant. Meglan & Lehman reported

on the expandable implants. Later Lew introduced a self tapping Vitallium screw implant

with conventional threads & square post.

Muratori & Pasquallini introduced hollow cores along with the screw threads. The

majority of these screw shaped implants were one piece & were not submerged, did not


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osseointegrate. It was emphasized that the fibrous peri implant membrane with its shock

absorbing feature preferred than bone fusing to implant.

In 1963 Dr. Linkow, American Dentist developed first screw type of implantVent Plant.

This was the first self tapping, self threading implant. It had an open cage like design that

went into bone first, with a few threads on solid body at the top. He used Vitallium first

latter on titanium.

b)Blade Implants (fig 34)14

Fig- 34:Blade implants

Linkow invented blade implants in 1967, long thin blade that will be surgically inserted

into the groove in the bone.

Abutment projecting out from the blade to this crown or attachment for denture can be

placed. It required the shared support of natural teeth also. It can be restored within

month so became most widely used in united states.


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Linkow modified the design configuration for broad applicability in maxilla & mandible,

narrow ridges.

c) Ramus Frame Implant (fig 35)

Fig - 35: Ramus frame implants

In 1970 Roberts & Roberts developed Ramus blade implants. It was to be positioned by

anchoring distally between the cortical plates in the ramus of the mandible. The

endosseous implant received stabilization from its anchorage in ramus area bilaterally &

in the symphyseal region.

Endodontic stabilizerAlthough endodontic stabilizer implants are endosteal implants, they differ fromother endostealimplants in terms of functional application. Rather than providing additional abutment support forrestorative dentistry, they are used to extend the functional length of an existing tooth root toimprove its prognosis[6] and when required, its ability to support bridgework. Modern endodonticstabilizers take the form of a long, threaded post that passes at least 5 mm beyond the apex ofthe tooth root into available bone. Endodontic stabilizers have been designed with parallel ortapered sides, smooth or threaded. The most successful endodontic stabilizers are threaded and

parallel-sided, with sluiceways in the threaded crests that prevent apical cement sealant frombeing expressed into bone by guiding it crestally. The parallel-sided threaded design controls thestress concentration at the apex of the root, protecting against fracture and trauma. [7]The endodontic stabilizer functions in the osteopreservation mode of tissue integration, becausethe tooth root through which it is inserted is subjected to normal physiologic micromovement asit heals. Endodontic stabilizers are placed and the procedure is completed in one visit, as the final

step of any conventional endodontic regimen.


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3-OTHER DESIGNS OF IMPLANTS

a) IMZ Implant System(fig 36)

Fig - 36: IMZ Implants

Kirsch developed the IMZ implant system in 1974. Since 1978 its in clinical use. Its an

intramobile cylinder endosseous two stage osseointegrated implant. The

polyoxymethylene & polyacetal are used as IME.

Its available in 3.5 to 4mm diameter and 8, 10, 13, 15mm length. Surface coating may be

titanium plasma spray or plasma sprayed Hydroxy apatite coated surface.

b)Lederman Screw Implant(fig 37)45


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Fig (37): lederman screw implant

In 1977 Dr. Philippe Lederman in collaboration with strauman company developed the Titanium

plasma spray screw type implant. In 1989 Lederman developed the New Ledreman screw

implant surface roughened by sand blasting & acid etching.

c) ITI Bone Fit Implant System(fig 38)

Fig (38) : ITI bone fit implant

Developed by International Team for Implantology. Its of two different types- Single

stage & two stage.

Its Transgingivally placed in healing phase so second surgical procedure for uncovering

the implant is avoided.

d) The Hand-Titanium Implant System


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Clinical use since 1985 in Switzerland & now in use world wide (Lederman 1986). Its a

conical, step- screw, pure Titanium implant with self thread.

Length- 10 to 20mm.

Diameter3.5 to 7mm.

In early 1980s Tantum introduced Omni R implant- A Titanium, root form implant with

horizontal fins. He then introduced Omni S implant for placing into bone grafted

maxillary sinus.

In 1983 EL Blasty & Kamel introduced the new endosseous implant material i.e. Poly

acrylic acid reinforced with ceramic alumina particles 0.3 microns. The hydrophilic

matrix swells in contact with aqueous solution. The gradual pressure on the surrounding

bone stimulates osseous activity. It is Implanted in canine, premolar sites with promising

results.

e) Mini Dental Implant(fig 39)

Fig - 39: Mini Dental Implant


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In 1985 Victor Sendax developed MDI. It has an ultra small diameter of 1.8 mm,

biocompatible Titanium alloy implant screws. Bulard added single one piece `O- ball

design.

f) Core Vent implant(fig 40)45

Fig - 40: Core vent implant

Developed by Dr. Gerald Niznick in 1986. Its a Hollow basket design made of Titanium

alloy. It comes in different fixture designs - ScrewVent, Micro-Vent, BioVent.

g) Endopore implant (fig 41)45

Fig - 41:Core vent implant


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A root form dental implant developed by Doughlas et al in 1996 made of Titanium alloy

& sintered with same alloy producing porous surface. It has Biological & clinical

advantages over the other implants .

h) Steri Oss System45

It was Introduced by Denar. Its made up of 99.9% Ti, tapered apex thread design & the

coronal 3rd highly polished surface.

Its available in 3.5 to 4mm diameter, length 12 mm,16mm, 20mm,& mini series

8mm,10mm,12mm length.

i) Novum Concept implant (fig 42)45,47

Fig- 42: Novum concept implant

Branemark developed the concept of providing a new set of teeth for the mandible in a

single day. It was clinically implicated in 1996. In this three titanium fixtures inserted,

mucosa is closed & base plate is placed over the fixtures & then the prosthesis is placed.

j) Zygomaticus Fixtures implants (fig 43)47


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Fig(43): Zygomatic Fixture Implants

In this the long fixture can be anchored in zygoma by approaching through the sinus. In

used in cases with a severely resorbed maxilla.

k) Bicortical Screw Implant(fig 44)45

Fig - 44: Biocortical Screw Implant

Its a self tapping type of dental implant. It has a diameter of 2.5, 3.5, 4.5, 5.5mm and

length of 21 -30mm. Post extraction insertion is done for single tooth replacement.

l) Osteoplate 2000(fig 45)47


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Fig - 45: Osteoplate 2000 implants

Its used for atrophic residual alveolar ridge. Conical plate with shoulder width 1.3 mm &

base 0.9 mm is used.

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PARTS OF A DENTAL IMPLANT.docx