RECENT ADVANCES IN DENTAL IMPLANTS AND MATERIALS-A REVIEW

RECENT ADVANCES IN DENTAL IMPLANTS AND

MATERIALS-A REVIEW

1 Dr. Nikhil Bhalchandra Awale, 2 Dr. Girish Suragimath, 3 Dr. A.

Siddhartha Varma, 3Dr. Sameer A. Zope, 4 Dr. Apurva A. Pisal

1,2,3,4 Department of Periodontology

2 Professor and Head of the Department

3 Reader, 4 Senior Lecturer

1,2,3,4 School of Dental Sciences, Krishna Institute of Medical Sciences

Deemed to be University, Karad, Maharashtra, India.

Email Address: [email protected]

[email protected]

[email protected]

[email protected]

[email protected]

Abstract

Tooth loss is very a very common problem; therefore, the use of dental implants is also a common practice.

Although research on dental implant designs, materials and techniques has increased in the past few years and is

expected to expand in the future, there is still a lot of work involved in the use of better biomaterials, implant design,

surface modification and functionalization of surfaces to improve the long-term outcomes of the treatment. This

paper provides a brief history and evolution of dental implants. It also describes the types of implants that have been

developed, and the parameters that are presently used in the design of dental implants. Finally, it describes the trends

that are employed to improve dental implant surfaces, and current technologies used for the analysis and design of

the implants.

Key words: Dental implants, History, Design, Surfaces modifications, Osseointegration, advances.

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INTRODUCTION

Missing teeth is a health problem associated with functional, cosmetic and psychological morbidity. The

most common cause of tooth loss is Periodontitis but it can also result due to many disease processes or

following any dental trauma, 1 other causes include dental caries, trauma, developmental Defects and

genetic disorders. That is when dental implants play a role in providing replacement of missing teeth/tooth

and restoring the function along with esthetic support in most. Dental implants have become an

increasingly common & reliable treatment option in clinical practice as loss of teeth is very common. Tooth

loss not only impairs quality of life but also indirectly affects the wellbeing of the individual. The missing

teeth affects the day to day activities of individuals like chewing, ability to talk (speech) which results in

low self-esteem, loss of confidence, less social interactions and thus hampers the work and daily

activities.2,3 The science of dental implantology is highly dynamic. It has not only undergone numerous

modifications and improvements after it was first introduced into the field of dentistry by Dr. Branemark

but also has proven to be a boon in disguise to the society with each improvement and advancement made

in the field

HISTORY 4

The desire to replace missing teeth with something similar to the root of a tooth dates back thousands of

years and includes civilizations such as ancient Chinese, Egyptians, Greeks and Etruscans. History has

revealed a ferrous metal tooth in a skull found in Europe which dated back to the time of Christ. Also it is

well known that the Incas from Central America used pieces of sea shells to replace missing tooth. While

the Chinese tapped them into the bone underlying the missing tooth. History shows then that it has always

made sense to replace a tooth with an implant in the approximate shape of a tooth. The first prototype of the

hollow cylinder implants used today was introduced in 1906 by Greenfield and was made of an iridium-

platinum alloy. The reaction of the underlying bone toward s the metal implant and the tolerance of tissue

was given importance in the early 1930s. Strock succeeded in anchoring a Vitallium (cobalt-

chromiummolybdenum alloy screw) within bone and immediately mounting a porcelain crown to the

implant. At the same time, Muller placed the first implant, made of an iridiumplatinum alloy into the oral

cavity. From the 1950s, numerous implantologists developed implant procedures. The first step in the field

of modern implantology was taken by a physician named Per-Ingvar Branemark. He conducted

experiments in vivo using Titanium chambers by placing them within the bone, discovered the particular

connection this metal was able to develop within the recipient tissue. In 1965, Branemark proposed a

‘‘bone-anchored bridge’’ to treat edentulous mandibles. The first-hand knowledge about osseointegration

as we know today was highlighted in two publications. Branemark in his study on rabbits observed firmly

attached titanium implant. Furthermore observation after a year showed absence of inflammation in the

peri-implant area bone. Also the soft tissue was found to have formed an attachment to the metal and bone

to the titanium. Even if the osseointegration was not accepted as a clinical achievement and was regarded

as impossible by many, the Branemark system of dental implants was introduced in 1971. Nowadays, the

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most frequently used implant material is Titanium and zirconia. As a result of Branemark’s extensive

studies, Titanium has become the gold standard in implant dentistry. However, the great revolution in the

field of ceramic materials with the use of zirconium dioxide and also other are in progress.

IMPLANT DESIGN

In order to fit the current surgical concepts and also for better patient care numerous implants with

difference in shape and size have evolved. Also, research on implant has revealed that even a subtle change

in the dimensions of the implant could have an influence on the rate of success of the implant.

1) Shape (Geometry)5

In the design of the implant the shape has an important role as the surface area of the implant and the

geometry affects not only the bone-implant interaction but also decides the distribution of forces and

ultimately the implant stability. The main types of implants are cylindrical, conical, stepped, screw

shaped, and hollow cylindrical. The tapered implants are widely used as it results in lateral

compression of bone and increased stiffness of the interfacial bone, which is reported to increase the

implant primary stability.

2) Threads6-8

The implant macro-structure is represented as threaded or non-thread out of which the threaded type is

the most commonly used implant design.There are four thread shapes which are most regularly used

when a dental implant is described. These are V-shaped, square-shaped, buttress thread and reverse

buttress threads.

Thread pitch- it is measured in an axis parallel to the screw. It is the distance from the center of the

thread to the center of the next thread.

In a single-threaded screw lead is equal to pitch, however in a double threaded screw, lead is double

the pitch and in a triple-threaded screw lead is triple the pitch. An implant with double threads would

insert twice as fast the single threaded and the triple threaded would only need a third of the required

time for a single thread

3) Length5

The dimension of an implant from the platform to the apex is referred as implant length. Most common

lengths are between 8 and 16mm which correspond quite closely to normal root length.The primary

stability of the implant is directly proportional to the length of the implant and surface contact. Thus

implants with long length and large surface area are preferred so as to dissipate the occlusal forces in

order to prevent interface stress and ultimately implant success..9 Over the years, commercially

available 7mm implants (usually the shortest on a company’s lineup) reported higher failure rates

compare to 8.5mm, 10mm and 11.5mm implants.10

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4) Diameter

The diameter of an implant is the dimension from the peak of the widest thread to the same point on

the opposite side of the implant.According to the diameter, implants may be classified as mini when

diameter is ≤2.7 mm,narrow when the diameter is >2.7 mm,regular when it ranges from 3.75−5 mm;

and wide when the diameter is >5 mm.It would be ideal to choose an implant with the diameter similar

to the root of the tooth being replaced.

a. Wide implant is indicated in following criteria

i. Poor quality bone;

ii. Adequate mesio-distal and bucco-lingual width but limited ridge height

iii. Immediate implant placement (after tooth extraction).

b. Narrow implant is indicated in following criteria

i. Mandibular or maxillary incisor replacement

ii. Limited edentulous space;

iii. Limited width of ridge (to avoid ridge augmentation surgery);

iv. Good emergence profile not achievable with a wide implant body.

v. Converging adjacent tooth roots

MODIFICATIONS OF HEX DESIGNS

EXTERNAL HEX10

The external hex type is the original prosthetic connection for the dental implants Designed by Dr.

Branemark. It is the most common type of prosthetic attachment and has proven to be a stable

prosthetic attachment for all kinds of restorations.

FEATURES: External hex has 0.7mm standard hexagon.

INTERNAL HEX

An internal hex type is a fairly common attachment with a greater stability due to its longer hex. It is

also more expensive compared to the external hex and patent rights are constantly being argued in the

market. FEATURE: 7-mm-deep hex below a 0.5- mm– wide, 45° bevel that distribute intraoral forces

deeper within the implant to protect the retention screw from excess loading.

MORSE TAPER

Internal tapered attachments allow for an abutment to be friction seated into the head of the implant

fixture. It is simpler to use because there are no screws.

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FEATURE: Tapered abutment post is inserted into the non-threaded shaft of a dental implant with the

same taper.

SPLINE10

The spline has proven to be more stable than other types with respect to anti-rotation. Its main

limitation is the weak resistance to lateral force.

THE ABUTMENTS11,12

The restorations that consist of crowns or fixed prostheses (bridges), and that are supported by

implants. There are seven types of abutments available for use in single and fixed implant supported

restorations.

I. CUSTOM-MADE ABUTMENTS

As per the requirement they may be made with or without a metal machined interface ring on

a wax or plastic pattern.Universal castable long abutments (UCLA) plastic patterns are an

example of these types of abutments

II. PRE-MACHINED (PREFABRICATED/READY-MADE)MODIFIABLE METAL

ABUTMENTS

They are prefabricated abutments that are adjustable and modifiable intra- and extra-orally

III. PRE-MACHINED (PRE-FABRICATED/READY-MADE), NON-MODIFIABLE

METAL ABUTMENTS

They are pre-fabricated abutments that cannot be modified or altered.

IV. ALL-CERAMIC ABUTMENTS

They are made entirely of ceramic that are densely sintered high-purity alumina (Al2O3)

ceramic

V. CAD/CAM MILLED ABUTMENTS

They are made from a block of titanium or ceramic and are customized according to the need.

VI. ANGULATED ABUTMENTS

The angulated abutments facilitates paralleling non-aligned dental implants where Inclination

range from 10-350 degree

VII. MULTI-UNIT ABUTMENT

In situations with greater dis-angulation, the angulated abutment is used which is one piece.

IMPLANT SURFACE CHARACTERISTICS

The surface properties of materials are regarded as decisive for the tissue response in association with

materials. There are three different properties as follows:

I) Mechanical properties.

The mechanical techniques induce the shaping of material surfaces by physical forces.

II) Topographic properties13

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The surface topography refers to the orientation of the surface irregularities and the degree of

roughness of the surface.

A. Based on the surface roughness14 (Wennerberg and coworkers)

1. Smooth surfaces: (Sa value < 0.5 μm)

(E.g. polished abutment surface).

2. Minimally rough surfaces: (Sa = 0.5-1.0 μm)

(E.g. turned implants).

3. Moderately rough surfaces: (Sa = 1.0-2.0 μm)

(E.g. most commonly used types).

4. Rough surfaces: (Sa > 2.0 μm).

(E.g. plasma sprayed surfaces)

B. Based on texture obtained

1. Concave texture: mainly by additive treatments like hydroxyapatite coating and titanium plasma

spraying.

2. Convex texture: treatment which is subtractive like blasting and etching.

C. Based on the orientation of surface irregularities.15

1. Isotropic surfaces: irrespective of the measuring direction the topography remains the same.

2. Anisotropic surfaces: as the name suggests it has difference in the roughness and have clear

directionality.

D. Based on morphological properties

1. Physicochemical: modification of surface energy, surface charge and surface composition to

improve the bone implant interface.

2. Morphological:alteration of surface morphology and roughness to influence cell and tissue

response to implants.

3. Biochemical:increased biochemical interaction of implant with bone

1) MACHINING16

The surface of the implant is untreated because at first the implant after being manufactured is subjected to

cleaning, decontamination, passivation followed by sterilization without any post sterilization finishing.

The implants that are machined are found to have more number of grooves and valleys making scope for

bone interlocking due to mechanical resistance.

2) TITANIUM PLASMA SPRAYING (TPS)17

In this method the powdered form of substances like titanium or calcium phosphate are projected onto the

roughened surfaces following heating at very high temperatures. This formsa coating on the surface of the

implant. The coating is of30 μ m to 50 μ m thickness. This procedure not only imparts a rough surface to

the implant but also increases the surface area.

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The increase in the surface area is upto 6 times. A 30μm thick film is formed on the surface of the implant

when the titanium particles are projected on to the surface wherein they undergo condensation followed by

fusion.

3) GRIT-BLASTING17

In this method the alterations in the surface are made by projecting hard particles of alumina and TiO2

at very high velocities thus imparting roughness to the surface. The degree of roughness is not only

dependent on the size of the particles, pressure of projection, time of blasting but the distance of the

implant surface from the source of particle. Hard ceramic or metallic particles are preferred for grid

blasting of titanium surfaces to be roughened. This method allows for improved adhesion thus

allowing for proper and timely proliferation and differentiation of osteoblasts. The only limitation of

this procedure being the residual particles being left out on the implant surfaces following the blasting.

4) ACID-ETCHING18,19

This method employs the technique of immersing the metallic implant into an acidic solution (HCl or

HF) thus increasing the thickness of the oxide layer and ultimately producing roughness due to

emergence of micropits onto the surface. The micropits range in size from 0.5 – 2 μm. The factors

which have an effect on this technique include the procedure time, temperature at which the procedure

was conducted and last but not the least the concentration of the acid used. The implant thus obtained

is found to have better and rapid ossteointegration as a result of improved homogeneous roughness,

improved cell adhesion and increased surface area. The implants which have been acid etched are

found to have better implant stability quotient as compared to the machined screws using a polymer to

simulate bone.

Modification techniques to enhance osseointegration

Dual acid-etched technique-

In this technique the implants are immersed in a mixture of two acids which are heated above 100 °C.

The acids produce micro rough surface. Commonly used acids include concentrated HCl and H2SO4

Sandblasted and acid etched surface (SLA)-

This technique is combination of two techniques which is sandblasting and acid etching. In

sandblasting the dental implants are sandblasted with large grits 250-500 μm. This makes the surface

rough. Now this is followed by acid etching using concentrated HCl and H2SO4. Following this the

surface is not only micro textured but also cleaned.

5) ANODIZATION20

This technique employs use of electrochemical energy wherein the implant is immersed in an

electrolyte solution and current is passed through the solution. The result is generation of micropores

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of various diameters along with increase in the oxide layer. The advantage of this technique being the

strong reinforcement of bone response as compared to the machined surfaces

Method for titanium implants anodisation

a) Acid (Sulphuric acid)

b) Non-acid electrolytes like

i. Sodium phosphate and Isopropyl phosphate in Ethylene glycol

ii. Ammonium pentaborate

iii. Calcium acetate and Calcium Glycerophosphate.

The oxides usually grow at the rate of 1.5 – 3 nm/V (also called as growth constant) in the various

electrolytes.

Bio-coat - (Color anodization)

Titanium is immersed into an electrolyte and connected as an anode leading to the formation of an

oxide film at the surface.

Bio-dize - (Alkaline grey anodization)

Similar to the Bio coat however the specific electrolyte allows the formation of thicker TiO2

layers in the range of micrometers.

Bio-bright - (Electropolishing)

Titanium is immersed into an electrolyte and is connected as an anode leading to the dissolution of

the titanium material

Innosurf - Modification of the Bio bright process. The removed layer of titanium is in the

range of 5 to 30 micrometers.

6) LASER TREATMENT21-23

Since its inception it has gained popularity in the dental field. The dental lasers are used for the

purpose of cleaning and sterilizing the implant. The underlying mechanism of decontamination being

physical property of laser along with its interaction with the tissue as aresult of scaterring, reflection,

absorption as well as elevation of temperature. The process involves use high intensity (5-15 GW/cm2)

nanosecond pulses (10-30 ns) of a laser beam striking a protective layer of paint on the metallic

surface. This creates a shock which transverses the implant and as it does so it improves the strength of

the implant and thus fatigue life and decreasing the chances of corrosion cracking. Numerous types of

lasers are available viz. argon ion, ruby, CO2, Nd:YAG, and excimer lasers. Of these the most preferred

being Nd:YAG laser.

7) RESORBABLE BLAST MEDIA (RBM)

Resorbable blast media (RBM) surface is formed by blasting the implant surface by only a

biocompatible material, Calcium phosphate ceramic that is fully resorbable, permitting its removal

after manufacturing resulting in a pure, clean textured titanium surface. The roughening process does

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not involve acid-etching. Hence, the RBM implant surface is free from acid-etching residues. It is also

not susceptible to titanium grain boundary degradation that can occur from aggressive acid etching

procedures.It produces a surface roughness of 20 to 25 μm. Life Core RBM implant is one such

implant.

8) ELECTROPHORETIC DEPOSITION (EPD)

EPD is a process in which colloidal particles, such as HA Nano precipitates which are suspended in a

liquid medium migrate under the influence of an electric field and are deposited onto a counter charged

electrode. The coating is simply formed by pressure exerted by the potential difference between the

electrodes. The major disadvantage of EPD is the need for post deposition heat treatment to densify the

coating.

9) OTHER CHEMICAL TREATMENTS

SOLVENT CLEANING

Removes oils, greases and fatty surface contaminants remaining after manufacturing process.

Organic solvents (aliphatic hydrocarbons, alcohols, ketones or chlorinated hydrocarbons),

surface active detergents and alkaline cleaning solutions.

ALKALINE ETCHING

A 1 μm thick gel of sodium titanate can be obtained when titanium with high degree of open

porosity and irregular topography is obtained when it is treated with 4-5 ML sodium

hydroxide at 600°C for 24 hours. Boiling alkali solution (0.2 ML sodium hydroxide, 1400°C

for 5 hours) produce a high density of Nano scale pits on the titanium.

PASSIVATION TREATMENTS

For obtaining a uniformly oxidized surface to improve corrosion resistance. Immersion of

titanium for a minimum of 30 minutes in 20-40 volume percentage solution of nitric acid at

room temperature. It is important to neutralize the implant after passivation. This can be

achieved by thoroughly rinsing and drying the implant.

10) . VACUUM TREATMENT

Glow-discharge treatment (cold plasma treatment): this method employs the use oflow-

pressure electrical discharge onto the surface of the implant. Two types of treatment options

available are plasma deposition method and plasma surface modification.

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In Plasma deposition – in this method a glow discharge is used to deposit the coating

material from a separate solid target (sputter deposition) and/or by reactions in the gas phase

(reactive sputtering or plasma polymerization).

In Plasma surface modification – in this method the exposure of sample surface to a glow

discharge id done so as to obtain a specific modification of the properties of surface.

In Ion implantation method – in this method the surface of the implant is bombarded with

high energy ions of approximately 100 KcV to 1 McV range. Here the ions penetrate the

surface of implant to typical depths of approximately 0.1-1μm.

III) PHYSIOCHEMICAL PROPERTIES.

Refer to factors such as surface energy¸ surface charge and surface composition. A surface with a high

energy has affinity for adsorption. In other words, an oral implant with high surface energy may show

stronger Osseo integration.

There are two broad types of chemical alterations:

A) ADDITION OF ORGANIC PHASES (GROWTH FACTORS)24

A number of growth factors has been tested for their effects on bone formation and implant

osseointegration.25,26

a) BONE MORPHOGENETIC PROTEINS (BMPs)27-30

Bone morphogenetic proteins (BMPs), members of the transforming growth factor

(TGF)-superfamily, are well known to be osteo- and chondro-inductive. BMPs are widely

used as an additive for bone graft material; its addition contributes for bone to implant

contact (BIC).In various studies the usage of BMP reported to improve and enhance

osteogenesis process, osteoblasts activity, chondroblast activity and osseointegration after

dental implantation. The applications of BMPs on Ti surface can improve the

osseointegration of dental implants and shorten the time period for implant integration.

b) PLATELET-DERIVED GROWTH FACTORS (PDGFS)

Platelet-derived growth factor as the name suggests are derived from platelets and are

found to have a role in the growth and development of not only bone cells but also tissue

of mesenchymal origin like the periodontal ligament31.

It not only plays an important role in vascular growth but also in healing of soft tissue

and this is achieved by promoting angiogenesis.32

c) TGF-8 (TRANSFORMING GROWTH FACTOR-BETA)

Transforming growth factor –beta plays a pivotal role in regulation of not only growth

but differentiation of tissue of bone origin, connective tissue. It also regulates the

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immunological system. Due to all these factors study by Lind et al on dogs found it to be

enhancing the mechanical fixation implants in bone along with enhancing ingrowth.

d) FIBROBLAST GROWTH FACTORS (FGFS)

The mesodermal and neuroectodermal origin tissue are regulated by fibroblast growth

factors. At present it consists of 7 members. They are found to have osteogenic as well as

angiogenic properties. Thus making them candidates for future prospects.

e) INSULIN GROWTH FACTORS (IGFS)

These are polypeptides which are synthesized by various tissues including the bone

tissue. They have been attributed in the growth of collagen tissue and may be beneficial

in increasing the bone mass when incorporated with the dental implant

B) ADDITION OF INORGANIC PHASES (HYDROXYAPATITE)33-38

Varying percentage of crystalline Hydroxyapatite, amorphous calcium phosphate and ßtricalcium

phosphate (ß-TCP) form the part of coatings. Numerous studies have evaluated the crystalline

nature of the implant coatings. The range of percentage was wide about 30% to 66%.

ADVANCES IN SURFACE TREAMENTS OF DENTAL IMPLANTS.

i. BIOMIMETIC CAP COATINGS

The alloys of titanium, alumina and ultra-high molecular weight polyethylene of substrates have

been used in making the biomimetic cap coatings. In this technique a thin layer is formed on the

surface of the implant by mimicking the process of mineralization of bone or tooth. Recent

advances include fluoride phosphate substitution on the titanium dioxide surface, leading to

localized calcium apatite deposition.39

A better cell response of dental implants can be achieved by the use of higher ratio of calcium and

phosphorus along with the addition of silver nanoparticles into the oxide.40

ii. ALBUMIN

Numerous studies have documented that the adsorption of bovine serum albumin (BSA) on

titanium powder has beneficial effect on the release of calcium nd phosphorus from the

coating of the implant. It displays its effect by having not only osteoconductive but also

osteoinductive property.41

iii. BISPHOSPHONATES (BPs) 42,43

In osteoporosis the bisphosphonates like alendronate, pamidronate have shown promising

results. Similar property of reduced bone turnover can be harnessed for better implant

survival.

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iv. ANTIBIOTICS

As in the case of orthopaedic surgeries perioperative antibiotics have documented in

decreased rate of infections. So also in the case of dental implants the antibiotic may be

injected close to the site of implantation. Furthermore co precipitation with biomimetic Ca-P

coating can provide an opportunity to load higher amount of antibiotics.44 Addition of zinc

and fluoride ions have shown to have improved efficacy in preventing infections.45

v. AMELOGENIN46

The amelogenin proteins form an important component of development of extracellular

matrix and thus the enamel. Incorporation into the implant will augment the implant success

rate.

vi. FLUORIDE

The calcification of bone is influenced by fluoride. Studies have revealed the osteopromoting

capacity of fluoride.Bone density and calcification of the bone have improved if fluoride is

available during remodeling process of the bone when incorporated with dental implant.The

rate of osteintegration and firm anchorage of the bone can be achieved with addition of

fluoride. (Roccuzzo and Wilson Jr., 2009).

vii. TETRACYCLINE47

Tetracycline is known for its antimicrobial property. Also recent studies have highlighted its

collagenase inhibiting property leading to increased cell proliferation and bone healing

viii. DISCRETE CRYSTALLINE DEPOSITION (DCD)

In this process the calcium phosphate particles of size 20-100nm are deposited on the surface

of implant. The implants are pre dual acid etched followed by deposition of calcium

phosphate onto the implant surface by sol-gel process named Discrete Crystalline Deposition

(DCD). Ultimately the incidence of infection is markedly reduces as there is reduced bacterial

adhesion. (Smeets et al., 2016).

ix. PHOTO FUNCTIONALIZATION

In this the dental implant is subjected to treatment with ultraviolet light.This treatment brings

about a change in the titanium oxide resulting in enhanced osseointegration, and slows down

age related degradations.

x. EXTRACELLULAR MATRIX PROTEIN COATING

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The extracellular matrix provides crucial guidance for osteoprogenitor cells that migrate to the

implant via interaction of integrins on the cell surface and RGD motifs of fibronectin. Upon

the release of BMP, these cells differentiate into osteoblasts. Studies done on use of

extracellular matrix protein coating have shown to have a positive impact on peri-implant

bone formation.

xi. PEPTIDE COATING

The peptides are biomolecules composed of short sequences of amino acids. Their unique

property facilitates osseointegration as well as inhibit bacterial overgrowth.

xii. BIOACTIVE GLASS COATINGS

The silica-based bioactive glasses have the property of are slowly resorbing synthetic

osteoconductive materials. They form a strong chemical bond with the underlying bone.

Studies by few authors have found implants with bioactive glass coating to have greater

osseointegration as compared to non-coated implants..48.

IV) ADVANCES IN DENTAL IMPLANT MATERIALS

I. TITANIUM IMPLANTS

Since its introduction in 1789 by Wilhelm Gregor titanium has been widely used in

implants. This can be attributed to its property of biocompatibility, ability to form stable

oxide layer. The limiting factor being aesthic concern due to the dark gray appearance of

the metal making way for a tooth colour implant like zirconia 49

II. POLY-ETHER-ETHER-KETONE (PEEK)49

PEEK is a high performance semi-crystalline thermoplastic polymer. The advantage

include very good strength and stiffness with an outstanding thermal and chemical

resistance—e.g., against oils and acids. Also the colourless and elastic modules

nature makes it resemblance to bone.However the limiting factor being disturbed

oseointegration.

III. ZIRCONIA IMPLANTS50

The name of the metal zirconium originates from the Arabic ‘‘zargun’’ (golden in

color), which in turn comes from the two Persian words Zar (gold) and Gun (color).

In 1975, Garvie et al. propose a model to rationalize the good mechanical properties

of Zirconia, by virtue of which it has been called ‘’ceramic steel’’Zirconia proved to

be a superior material of choice as it was inert along with minimum ion release had

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higher fracture resilience and higher flexural strength. Due to its property of better

osseointegration, minimal plaque accululation and better maintenance of soft tissues

and last but not the least aesthetic appeal has made it use widespread in implants.

ZIRCONIA TOUGHENED ALUMINA (ZTA) AND ALUMINA

TOUGHENED ZIRCONIA (AZT)51

These are another class of bioceramics in use for dental implants.. They are called either

Zirconia toughened Alumina (ZTA) when Alumina is the main component (70–95 %), or

Alumina Toughened Zirconia (ATZ), when Zirconia is the main component.The

advantages includes characteristics of Alumina (high hardness, high stiffness) with the

mentioned properties of Zirconia, i.e., the high strength and high toughness, with

improvement of slow crack growth resistance.

POWDER INJECTION MOLDING (PIM)

An alternative to classical machining for preparing Zirconia and other ceramics is the

Powder injection molding (PIM), also called ceramic injection molding (CIM). It is a

combination of injection molding and powder technology mixing, injection molding,

debinding, and sintering. Various methods are available and depend on the pressure used

for molding and injection.51

IV. TANTALUM IMPLANTS52-54

Tantalum with its success in orthopaedic implants has entered into the arena of

dental implants. Its property of being corrosive resistant and better osseointegration

has led to emergence of its use in the implants.

.

PRODUCTION OF POROUS TANTALUM TRABECULAR METAL (PTTM)

The porous tantalum trabecular metal as the name suggests has high volumetric

porosity, high frictional characteristics and low modulus elasticity.

ADVANTAGES OF PTTM-ENHANCED TITANIUM DENTAL IMPLANTS

1) Due to the presence of open-cell dodecahedron repeat structure angiogenesis takes

place resulting in better implant anchorage.

2) Tantalum layer of PTTM, when oxidized, is highly unreactive, and therefore,

biocompatible in the body.

3).Tantalum does not exhibit toxicity to surrounding cells, nor does it inhibit local

cell growth, i.e. osseous in growth of surrounding bone

V. TRANSITIONAL IMPLANTS

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Their diameter ranges from 1.8 to 2.8 mm and length ranges from 7 to 14 mm.

Transitional implant are fabricated with pure titanium in a single body with treated

surface. They play an important role by absorbing the masticatory stress thus aidind

in the healing phase.

COMMERCIALLY AVAILABLE TRANSITIONAL IMPLANT SYSTEM

- Immediate Provisional Implant System –IPI (Nobel Biocare) - Modular

Transitional Implant System -MTI (Dentatus)

-TRN/ TRI Implants (Hi Tec implants)

VI. ONE-PIECE IMPLANTS55

Abutment and implant body are in one piece and not separate.They are commercially

available in 3 mm diameter and 12, 15, and 18 mm length.

(a) Maximum strength – It is one-piece, titanium alloy construction provides

maximum strength, while its 3.0 mm diameter allows placement in areas of

limited tooth-to-tooth spacing.

(b) Minimal surgery – Because one-piece implants are placed using a single-stage

protocol, the soft tissue experiences less trauma than typical two-stage protocols

with maximum esthetics.

VII. TAPERED IMPLANTS & GROOVY IMPLANTS

These implants offer in one body geometry, parallel walled with a diminishing thread

depth toward the apical of the implant and secondary groove underneath each thread

to enhance the initial stability. Cutting flutes incorporated at the apex of the implant

give this implant design self-tapping capability.Dehiscence and fenestration is

reduced.

VIII. SHORT LENGTH IMPLANTS

In patients with reduced alveolar height short implants are preferred as to avoid more

invasive surgical procedure and thus overall hospitalization and cost of treatmemt.

.

IX. MINI IMPLANTS56

As the name suggests these are ultra-small sized titanium screws of diameter 1.8 mm

wide. These are used in cases wherin acceptable and satisfactory function cannot be

achieved with conventional prosthesis. For example, in patients with flabbyridges,

atrophic ridges or in cases with poor availability of residual bone where there is

denture instability or lack of retention, commonly seen in edentulous mandible.

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X. PTERYGOID IMPLANTS

Pterygoid implants have the advantage of allowing anchorage in the posterior

atrophied maxilla, eliminating the need of sinus lifts or bone grafts. In addition

posterior cantilever can be eliminated and axial loading is improved. These implants

can be placed in two different locations such as pterygoid process or in a most

anterior position, the pterygomaxillary process.However, the implant length and

angulations vary between these two locations. Shorter implants are generally placed

in the pterygomaxillary region with angulations of 10–20 to simulate the proper

angulations of the third molar. On the other hand, the longer implants are anchored

to the pterygoid plate of sphenoid bone.

XI. ZYGOMATIC IMPLANTS

In situations like unsuitable condition in posterior maxilla for implant insertion

specific implants like zygomaticus fixture were developed as asolution. There are 8

different lengths, ranging from 30 to 52.5 mm and 45o angulated head to compensate

for the angulation between the zygoma and the maxilla.

XII. LIGAPLANT57

This technology is nothing but combination of the PDL cells with implant

biomaterial. Currently research are going on in making this implant a noble one.

Ligaplants has certain properties like:

1. PDL cells act as a soft, richly vascular, and cellular connective tissue which

permits forces elicited during masticatory function and other contact movements to

be distributed to the alveolar process via alveolar bone proper.

2. It act as a, shock absorber giving the tooth some movement in the socket.

3. It provides Proprioception.

FUTURE TRENDS

Future developments of biomaterial surfaces will include more and more sophisticated and multi (bio)

functional surfaces. (Ratner 1996, Sackmann 1966). The latter include the following aspects: 58

1. An almost revolutionary development is ongoing with regard to the possibilities for building up the

micro-architecture of surfaces. This will be exploited to optimize the 3-D surface architecture, with the

intention of functionally matching different biological entities such as proteins, cell processes and whole

cells. This matching aims at recognition at both the molecular and cell size levels.

2. The micro-architectural functionality mentioned will be combined with corresponding chemical patterns

working in synergy with the micro architecture.

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3. Controlled surface porosity will provide new functions, influencing cell surface interaction, transport of

nutrients, and signal substances, release of functional additives, etc.

4. Programmed dissolution of multilayered surfaces provides new opportunities to optimize the bio material

surface for different periods of the healing phase. Such time programming of the surface can be used to

expose different micro-architectures, different chemical patterns and different porosities at different times.

It also provides opportunity of time-programmed release of different inorganic and organic stimuli, like

growth hormones.

5. By the use of soft, visco-elastic over layers, the mechanical properties of surfaces at the macro and micro

scale can be optimized for the interface. Such over layers may involve bio membranes arid hydrogels.

6. Enhancement of bone-titanium integration profile with UV-photo functionalized titanium- Photo

functionalization describes an ultraviolet light treatment of dental implants taking place immediately before

their placement.

CONCLUSION

Dental Implants are used to support single and multiple unit restorations in the upper and lower jaws. It has

the provision of being placed in the healed bone or the socket of the missing tooth. Also the structure of the

implants makes it possible to place it in a bone irrespective of the height i.e it can be placed in a bone with

less height as well as less width. The implant can be placed with flap or flapless technique. A thorough

understanding of the maxillofacial anatomy is recommended so that bi-cortical engagement is achieved.

The research and development going on these implants have made them a viable option for restoring

atrophied jaws as they don’t require extensive augmentation and allow for immediate loading. They can

also be placed with a flapless technique and can be combined with any implant. Despite of the data

available on their success in treating a variety of cases these implants have gained little trust among

conventional implantologists, it seems further Research and development and more concrete data on

clinical cases are required to prove their efficacy as a replacement to conventional implants.

Hence, truthful efforts to achieve this goal along with a thorough training of the dental professionals to

perform as a team and long-term periodic maintenance by the patients surely will make dental implants the

propitious future of dentistry.

REFERENCES

[1]. Gaviria L, Salcido JP, Guda T, Ong JL. Current trends in dental implants. J Korean Assoc Oral

Maxillofac Surg 2014; 40(2):50-60.

[2]. Shabana Begum SK, Reddy VC, Kumar RK, Sudhir K M, Srinivasulu G, Noushad Ali SK. Tooth

loss prevalence and risk indicators among adult people visiting community health centres in

Nellore district, Andhra Pradesh: A cross-sectional study. J Indian Assoc Public Health Dent

2016; 14:413-8.

Parishodh Journal


ISSN NO:2347-6648

Page No:2668

[3]. Petersen PE. The World Oral Health Report 2003: continuous improvement of oral health in

the 21st century – the approach of the WHO Global Oral Health Programme. Community

Dent Oral Epidemiol 2003; 31 Suppl 1:3-23

[4]. Duraccio D, Mussano F, Faga MG. Biomaterials for dental implants: current and future

trends. J Mater Sci-Mater Med. 2015; 50:4779–812.

[5]. Warreth A, Ibieyou,N., O’Leary,RB, Cremonese, M, Abdulrahim, M. . Dental implants: An

Overview. Dental Update 2017;44(7), 596-620.

[6]. Manikyamba, Yenumula J B, Suresh Sajjan Mc, A. Vijaya Rama Raju, Bheemalingeshwara Rao

and Chandrasekharan K Nair. “Implant thread designs: An overview.”Trends Prosthodont

Dent Impl.2018;1:11-19.

[7]. Gracis S, Michalakis K, Vigolo P, Vult von Steyern P, Zwahlen M, Sailer I. Internal vs. external

connections for abutments/reconstructions: a systematic review.Clin Oral Implants

Res. 2012 Oct;23 Suppl 6:202-16.

[8]. Binon PP.Implants and Components: entering the new millennium. Int J Oral Maxillofacl

Implants 2000; 15(1):76-94.

[9]. Block MS, Delgado A, Fontenot MG. The effect of diameter and length of hydroxylapatite-

coated dental implants on ultimate pullout force in dog alveolar bone. J Oral MaxillofacSurg

1990; 48(2):174-8.

[10]. Richard Palmer. Dental implants. Introduction to dental implants. British Dent

J.1999;187(3):127-132.

[11]. Warreth A, Fesharaki H, McConville R, McReynolds D. An introduction to single implant

abutments. Dent Update 2013; 40(1): 7−17.

[12]. WarrethA, McAleese E, McDonnell P, Slami R, Guray SM. Dental implants and single

implant-supported restorations. J Ir Dent Assoc 2013; 59(1): 32−43.

[13]. Cooper LF. A role of surface topography in creating and maintaining bone at titanium

endosseous implants. J Prosthet Dent.2000;84(5):522– 34

[14]. Wennerberg A, Albrektsson T, Lausmaa. Torque and histomorphometric evaluation of

c.p. titanium screws blasted with 25- and 75-microns-sized particles of Al2O3.J Biomed

Mater Res.1996; 30(2):251-60.

[15]. Brunette DM. The effects of implant surface topography on the behavior of cells. Int J

Oral Maxillofac Implants.1998; 3:231-46.

Parishodh Journal


ISSN NO:2347-6648

Page No:2669

[16]. Searson LJ. History and development of dental implants. In: Narim L, Wilson HF, eds.

Implantology in general dental practice. London, Chicago: Quintessence Publishing Co;

2005:19-41.

[17]. Coelho PG, Granjeiro JM, Romanos GE, Suzuki M, Silva NR, Cardaropoli G, Thompson VP,

Lemons JE. Basic research methods and current trends of dental implant surfaces. J Biomed

Mater Res B ApplBiomater. 2009; 88(2):579-96.

[18]. Le Guéhennec L, Soueidan A, Layrolle P, Amouriq Y. Surface treatments of titanium

dental implants for rapid osseointegration. Dent Mater 2007; 23:844-54.

[19]. Dos Santos MV, Elias CN, Cavalcanti Lima JH. The effects of superficial roughness and

design on the primary stability of dental implants. Clin Implant Dent Relat Res 2011; 13:215-

23.

[20]. Gupta A, Dhanraj M, Sivagami G. Status of surface treatment in endosseous implant: a

literary overview. Ind J Dent Res 2010; 21:433-8.

[21]. Park CY, Kim SG, Kim MD, Eom TG, Yoon JH, Ahn SG. Surface properties of endosseous

dental implants after NdYAG and CO2 laser treatment at various energies. J Oral

MaxillofacSurg 2005; 63:1522-7.

[22]. Romanos G, Ko HH, Froum S, Tarnow D. The use of CO2 laser in the treatment of peri-

implantitis. Photomed Laser Surg 2009; 27:381-6.

[23]. Romanos GE, Gutknecht N, Dieter S, Schwarz F, Crespi R, Sculean A. Laser wavelengths

and oral implantology. Lasers Med Sci 2009; 24:961-70.

[24]. Ehrenfest DM, Coelho PG, Kang BS, Sul YT, Albrektsson T. Classification of

osseointegrated implant surfaces: materials, chemistry and topography. Trends in

biotechnology.Trends Biotechnol. 2010 Apr; 28(4):198-206.

[25]. Champagne CM, Takebe J, Offenbacher S, Cooper LF. Macrophage cell lines produce

osteoinductive signals that include bone morphogenetic protein-2. Bone 2002: 30; 26–31.

[26]. Doukas J, Chandler LA, Gonzalez AM, Gu D, Hoganson DK, Ma C, Nguyen T, Printz MA,

Nesbit M, Herlyn M, Crombleholme TM, Aukerman SL, Sosnowski BA, Pierce GF. Matrix

immobilization enhances the tissue repair activity of growth factor gene therapy vectors.

Hum Gene Ther 2001:12; 783–798.

[27]. Chang PC, Liu BY, Liu CM, Chou HH, Ho MH, Liu HC, Wang DM, Hou LT. Bone tissue

engineering with novel rhBMP2-PLLA composite scaffolds. J Biomed Mater Res 2007; 81:771-

80.

[28]. Moradian-Oldak J, Wen HB, Schneider GB, Stanford CM. Tissue engineering strategies

for the future generation of dental implants. Periodontol 2000 2006; 41:157-76.

Parishodh Journal


ISSN NO:2347-6648

Page No:2670

[29]. Brigaud I, Agniel R, Leroy-Dudal J, Kellouche S, Ponche A, Bouceba T, et al. Synergistic

effects of BMP-2, BMP-6 or BMP-7 with human plasma fibronectin onto hydroxyapatite

coatings: A comparative study. ActaBiomater 2017; 55:481-92.

[30]. Liu T, Zheng Y, Wu G, Wismeijer D, Pathak JL, Liu Y, et al. BMP2-coprecipitated calcium

phosphate granules enhance osteoinductivity of deproteinized bovine bone, and bone

formation during critical-sized bone defect healing. Sci Rep 2017; 7:418.

[31]. Graves DT, Kang YM, Kose KN. Growth factors in periodontal regeneration. Compen

Suppl.1994:S672-7.

[32]. Hollinger JO, Hart CE, Hirsch SN, Lynch S, Friedlaender GE. Recombinant human

platelet-derived growth factor: biology and clinical applications. J Bone Joint Surg Am. 2008

Feb 1; 90(Suppl1):48-54.

[33]. Kay JF. Calcium phosphate coatings for dental implants. Dent Clin North Am 1992; 36:1–

18.

[34]. Kim Y, LeGeros J, LeGeros R. Characterization of commercial HAcoated dental implants

[abstract 287]. J Dent Res 1994; 73:137.

[35]. LeGeros RZ, Craig RG. Strategies to affect bone remodeling: Osseointegration. J Bone

Miner Res 1993; 8(supplement):583–596.

[36]. Zablotsky MH. Hydroxyapatite coatings in implant dentistry. Implant Dent 1992; 1:253–

257.

[37]. Nery EB, LeGeros RZ, Lynch KL, Lee K. Tissue response to biphasic calcium phosphate

ceramic with different ratios of HA/bTCP in periodontal osseous defects. J Periodontol 1992;

63:729–735.

[38]. LeGeros RL. Calcium phosphates in oral biology and medicine. In: Meyers HM (ed).

Monographs in Oral Science. Basel, Switzerland: Karger, 1991:154–171.

[39]. Ellingsen JE. A study on the mechanism of protein adsorption to TiO2. Biomaterials

1991; 12:593-6.

[40]. Marques Ida S, Alfaro MF, Saito MT, da Cruz NC, Takoudis C, Landers R, et al. Biomimetic

coatings enhance tribocorrosion Behavior and cell responses of commercially pure titanium

surfaces.Biointerphases 2016;11(3):031008

[41]. Yu X, Qu H, Knecht DA, Wei M. Incorporation of bovine serum albumin into biomimetic

coatings on titanium with high loading efficacy and its release behavior. J Mater Sci Mater

Med 2009; 20:287-94.

Parishodh Journal


ISSN NO:2347-6648

Page No:2671

[42]. Aggarwal R, Babaji P, Nathan SS, Attokaran G, Santosh Kumar SM, Sathnoorkar S, et al.

Comparative clinicoradiographical evaluation of effect of aminobisphosphonate (sodium

alendronate) on peri-implant bone status: Controlled clinical trial. J IntSocPrev Community

Dent 2016; 6:285-90.

[43]. Alenezi A, Chrcanovic B, Wennerberg A. Effects of local drug and chemical compound

delivery on bone regeneration around dental implants in animal models: A systematic review

and meta-analysis. Int J Oral Maxillofac Implants 2018; 33:e1-18.

[44]. Ferguson J, Diefenbeck M, McNally M. Ceramic biocomposites as Biodegradable

antibiotic carriers in the treatment of bone infections. J Bone Jt Infect 2017; 2:38-51.

[45]. Kulkarni AA, Pushalkar S, Zhao M, LeGeros RZ, Zhang Y, Saxena D, et al. Antibacterial and

bioactive coatings on titanium implant surfaces. J Biomed Mater Res a 2017; 105:2218-27.

[46]. Terada C, Komasa S, Kusumoto T, Kawazoe T, Okazaki J. Effect of amelogenin coating of

a nano-modified titanium surface on bioactivity. Int J Mol Sci. 2018; 19 pii: E1274Google

Scholar]

[47]. Mohan S, Baylink DJ. Bone growth factors. Clin Orthop Relat Res 1991; 263:30-48

[48]. Parnia F, Yazdani J, Javaherzadeh V, MalekiDizaj S. Overview of nanoparticle coating of

dental implants for enhanced osseointegration and antimicrobial purposes. J Pharm

PharmSci 2017; 20:148-60.

[49]. Osman RB, Swain MV. A critical review of dental implant materials with an emphasis on

titanium versus zirconia. Materials (Basel) 2015; 8:932-58.

[50]. Ozkurt Z, Kazazoğlu E. Zirconia dental implants: A literature review. J Oral Implantol

2011; 37:367-76.

[51]. Duraccio D, Mussano F, Faga MG. Biomaterials for dental implants: current and future

trends. J Mater Sci-Mater Med. 2015; 50:4779– 812.

[52]. SompopBencharit. Development and Applications of Porous Tantalum Trabecular Metal

Enhanced Titanium Dental Implants. Clin Implant Dent Relat Res. 2014;16(6): 817–826.

[53]. Kock W, Paschen P. Tantalum - Processing, Properties and Applications. Jom-J Min Met

Mat S. Oct; 1989 41(10):33–39

[54]. Levine BR, Sporer S, Poggie RA, Della Valle CJ, Jacobs JJ. Experimental and clinical

performance of porous tantalum in orthopedic surgery. Biomaterials. 2006 27(27):4671–

4681.

[55]. Hermann JS, Cochran DL, Hermann JS, Buser D, Schenk RK, Schoolfield JD. Biologic width

around one- and two-piece titanium implants. Clin Oral Implants Res 2001; 12:559–571

Parishodh Journal


ISSN NO:2347-6648

Page No:2672

[56]. Tu CY, Lin LD, Wang TM, Hsu YC, Lee MS. Using mini dental implants to improve the

stability of an existing mandibular complete denture in a patient with severe ridge

resorption. J ProsthodImplantol 2012; 1:48-52

[57]. Benjamin A, Mahajan R, Sura S, Suthar N. 'Ligaplants' The Next Generation Implants.

IJIRS 2014; 3(7): 571-9.

[58]. Abrahamssonl, Berglundh T, Linder E, Lang NP, Lindhe Early bone formation adjacent to

rough and turned endosseous implant surfaces. An experimental study in the dog. Clin oral

implants res 2004; 15:381392.

Parishodh Journal


ISSN NO:2347-6648

Page No:2673

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RECENT ADVANCES IN DENTAL IMPLANTS AND MATERIALS-A REVIEW