Implants the future of prosthodontics

IMPLANTS The Future of

Prosthodontics

Kalpa PandyaRachayta ParikhPriyank Pareek

(Final B.D.S.)

A prosthetic device or alloplastic material implanted into the oral tissue beneath the mucosal or/and periosteal layer and/ or in the bone to provide retention and support for the fixed and removable prosthesis. - GPT

What is an Implant???

History• 936 – 1013 First documented placement of implants Albucasis de Condue– used ox bone to replace teeth

• 1809 Maggiolo - Gold roots which were fixed with adjacent teeth by means of spring

• 1887 Platinum post coated with lead

• 1895 Gold or iridium tubes were implanted – Bonewell

• 1905 Porcelain corrugated root implant

• 1913 Hollow basket implant meshwork or iridium , platinum , gold - Greenfield

• 1948 Insertion of first viable subperiosteal implant – Goldberg

• 1952 Threaded implant design of pure titanium Endosteal implants - Branemark

Single/multiple missing tooth/Teeth

What are the treatment options available ???????

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Single/multiple missing tooth/Teeth1. Removable Partial Denture (R.P.D.)

2.Fixed Partial Denture (F.P.D.)

3. Implant Prosthesis

Removable Partial Denture (R.P.D.)

DISADVANTAGES :-1. do not maintain bone

- compromise the esthetic result

2. bulk – need for cross arch stabilization

3. food debris , plaque

4. movement-speech-function

5. highest loss of abutment teeth

Fixed partial denture (F.P.D.)

DISADVANTAGES :-1. caries and endodontic failure of abutment teeth is the most common failure

2. increased plaque retention of pontic increases caries and periodontal disease risk 3. damage to healthy teeth

4. fracture ( porcelain , tooth )

5. esthetics ( anterior region )6. uncemented restorations

Fixed partial denture (F.P.D.)…

• It is contra indicated in 1. Poor abutment teeth support

2. inadequate hard and soft tissue in esthetic regions

3. patient desire

4. young patients with large pulp horns

Implants for single/multiple tooth

replacementADVANTAGES :-1. Adjacent teeth do not require splinted restoration

- less risk of caries- less risk of endodontics- Less risk of porcelain fracture- Less risk of uncemented restoration- Less fracture of tooth

2. Psychological need of patient3. Improved hygiene conditions

- less decay risk- less pontic overhang

4. Decreased cold and contact sensitivity5. Improved esthetics6. Maintains bone in site7. Decreases adjacent tooth loss

Treatment options

Conventional removable dentures Implant supported prosthesis

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Completely Edentulous Patient

Decreased performance of conventional complete dentures

1. Bite force is decreased from 200 psi to 50 psi2. Masticatory efficiency is decreased3. More drugs are required to treat gastrointestinal disorders4. Food selection is limited5. Healthy food intake is decreased

Implants for complete dentures1. maintain bone2. restore and maintain occlusal vertical

dimension3. maintain facial esthetics (teeth positioned for

appearance versus decreasing denture movement )4. Improve phonetics5. Improve occlusion6. Improve / regain oral proprioception7. Increase prosthesis success8. Maintains muscle of mastication and facial

expression9. Reduce size of prosthesis10. Improve stability and retention of removable

prosthesis11. More permanent replacement12. More psychological health

Indications for implants• Edentulous patient• Partially edentulous patient with history of difficulty in wearingR.P.D.• Patient requiring long span F.P.D.treatment• Patient who refuses wearing a removable prosthesis• Patient with severe changes in C.D.bearing tissues• Poor oral muscular coordination• Parafunctional habits that compromise prosthesis stability• Unrealistic patient expectation for complete denture• Hyperactive gag reflex• Patient psycologically against removable prosthesis• Unfavourable number and location of abutments• Single tooth loss, avoid preparation of sound teeth

ATTACHMENT MECHANICS

Mechanism Of Integration Of Endosteal Implants

2 concepts were proposed

1. Dr. Branemark conceptconcept of osseointegration

2. Weiss conceptconcept of fibro – osseous integration

WEISS THEORY

1. fibro ossseous ligament formed between implant and the bonecollagen fibers at bone implant interface

ligament = periodontal ligament

1. early loading of the implant was advocated• Fibrous connective tissue does not act as shock absorber nor

resemble PDL.• The non-mineralised connective tissue results from inflammtion

with a tendency to• proliferate, gradually increasing implant mobility.

BRANEMARK’S THEORY OF OSSEOINTEGRATION

• Bone is laid very close to the implant material without an intervening Connective tissue

• “the apparent direct attachment or connection of osseous tissue to an inert alloplastic material without intervening connective tissue”

- G.P.T.

• IMPLANT should be left out of function during the healing phase

The Interface

• Surgical area undergoes a remodelling process just like an extraction site

• If overloading then - implant failure

• Bone grows into the irregularities( macroscopic & microscopic ) of the implant surface

• depending on the reaction with bone :-1. bioactive ( hydroyapatite )2. bio – inert ( metals )

MECHANISM OF OSSEOINTEGRATION

First mechanism• Integration occurs mainly through osteoconduction

• Connective tissue scaffolding

• Bone-producing cells( osteoblasts ) migrates

Second mechanism• “de novo” bone formation wherein a mineralized interfacial matrix is

deposited along the implant surface• Surface topography will determine the bond strength of bone to the

implant surface

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Factors Affecting Osseointegration

1. Occlusal load• - 2 stage implant insertion is advocated• - overloading prematurely will cause failure

2. Biocompatibility of material• - commercially pure titanium• - commercially pure noibium• - hydroxyapetite

3. Implant design• - most conducive - cylindrical

4. Implant surface• - mild surface roughness

Factors Affecting Osseointegration

5. Surgical site• healthy site is required

6. Surgical technique• minimum possible trauma

7. Infection control

CLASSIFICATION OF IMPLANTS

I) Depending on the placement within the tissues

• Epithelial implants

• Epiosteal / Subperiosteal implants• Endosteal implants• Transosteal implants

Epithelial implants

• Implant is inserted into the oral mucosa

Disadvantages• 1. painful healing• 2. requirement of continual wear

Epiosteal / Subperiosteal Implant• Receives primary bone support

by resting on it• Placed directly beneath the

periosteum overliying the bony cortex

Disadvantages : 1) Slow, predictable rejection of

the implant 2) Bone loss associated with

failure

Endosteal ImplantsExtends into basal bone for supportIt transects into 1 cortical plate

Endosteal implants

Root form implants -Used over vertical column of bone

Plate form implants -used over horizontal Column of bone

1. Cylinder2. Screw root form3. Combination

Ramus frame implants

Transosteal Implant

• Also called as Staple Bone Implant, Transmandibular Implant

• Penetrates both cortical plate and passes through the entire thickness of the alveolar bone

• Use restricted to anterior area of mandible

II) Depending on the materials used

i) METALLIC IMPLANTS• titanium• cobalt chromium molybdenum alloy-

Titanium aluminum vandium• Cobalt chromium molybdenum• Stainless steel• Zirconium• Tantalum• Gold• Platinum

2. NON – METALLIC IMPLANTS- ceramics

- carbon

Depending On Their Reaction With Bone

• Based on the ability of implant to stimulate bone formation

1. Bio active• Hydroxyapatite• Tri Calcium Phosphate• Calcium Phosphate

• 2. Bio inert metals

Most commonly used

– Commercially pure (CP) titanium– Titanium-aluminum-vanadium alloy (Ti-6Al-4V) -

stronger & used with smaller diameter implants

Titanium

•Lightweight•biocompatible•corrosion resistant (dynamic inert oxide layer)•strong & low-priced•It is 6 times stronger than compact bone•Its modulus of elasticity is 5 times greater than that of compact bone (thus equal mechanical stress transfer)

PARTS OF AN IMPLANT

Generic Prosthetic Component Terminology

• Generic language for endosteal implant was developed by Mish & Mish (1992 )

• The order in which it is presented follows the chronology of insertion to restoration

Generic implant body terminology

1. Implant body ENDOSTEAL IMPLANTS

- root form designed to use vertical column of bone , similar to root of natural tooth

3 different categories 1. cylinder implants

2. screw design implants3. combination

Cylinder Implants-coating or surface condition provide microscopic retention to the bone

hydroxyapatitetitanium plasma spray

- pushed or tapped into prepared bone site- ease of placement

Screw Design Implants- slightly smaller prepared bone site- macroscopic retentive elements

Combination

crest module ( cervical geometry )

body

apex

Implant Body Regions3 parts

1. crest module ( cervical geometry )2. body3. apex

Implant Body Regions

Body- designed for implant bone interface

Crest module

- designed to retain the prosthetic component

- transition zone from implant body design to transosteal region at the crest of the ridge

- has a platform on which abutment is seated

- when it is a smooth and polished metal – cervical collar

abutment

Implant body

prosthesis

superstructure

Prosthetic AttachmentAbutment

portion of the implant that supports or retains a prosthesisor implant superstructure

Superstructure metal framework that attaches to the implant abutment and provides either retention for removable prosthesis or framework for fixed prosthesis

Categories of implant abutmentbased on method by which prosthesis or superstructure is retained to

the abutment

1. Screw retention

2. cement retention

3. for attachment• attachment device to retain a removable prosthesis

Prosthesis fabrication

• Impression is necessary to transfer the position and design of implant or abutment to the master cast for prosthesis fabrication

• Transfer coping – used to position a dye in an impression

Two types of transfer coping1. direct transfer coping2. indirect transfer coping

Laboratory fabricationAnalog – • defined as something that is

analogous to something else

• Analog is placed on the transfer coping and the impression is poured

Prosthetic coping is a thin covering usually designed to fit theImplant abutment for screw retention

It serves as a connection between abutment and prosthesis or superstructure

Implant system broadly are of 2 types

Two stageOne stageimmediate

1. one piece implant systemimplant body + prosthodontic

abutment

2. two piece implant systemimplant systemprosthodontic abutment

Implant surgery

Implant surgery…Two stage surgery

1st surgery- implant body placed below the soft tissue

after initial bone healing has occurred2nd surgery

-soft tissue are reflected- permucosal element or abutment is attached

One stage surgery1st surgery

- implant and permucosal element placed after initial bone healing has occurred -

abutment replaces the permucosal element without reflection of flap

Implant body

First stage cover screw

Second stage permucosal extension or healing abutment

AbutmentA) for screw retentinB) for cement retentionC) for attachment

Hygiene screw

Transfer copingA) directB) indirect

AnalogA)implant bodyB) abutment

coping

Prosthesis screw

PROSTHETIC OPTIONS IN IMPLANT DENTISTRY

Types of prosthesis can be given

• 1. fixed• 2. removable

FP 1 : Fixed prosthesis• Replaces only crown• Looks like natural tooth

Types of prosthesis can be given…

• FP – 2 : • fixed prosthesis replaces crown and portion

of root• hyper-contoured gingival half


• FP – 3 : Fixed prosthesis• Replaces missing

crown ,gingival color and portion of edentulous site


RP – 4 • Removable prosthesis

Overdenture supported completely by implant


RP – 5 : • Removable

prosthesis, overdenture supported both by soft tissue and implant

Dental examination

Bone density classification

Dense cortical (D1) bone • Highest bone implant contact (BIC) > 80%• Anterior region of mandible very

dense compact bone

Dental examination…

• Dense to thick porous cortical and coarse trabecular bone (D2)

• BIC = 70%

1. Dense to porous compact bone on the outside and coarse trabecular bone on the inside

2. Anterior and posterior mandible

Dental examination…• Thin porus cortical and fine

trabecular bone (d3) BIC = 50 %

1. Thinner porous compact bone and fine trabecular bone

2. Anterior or posterior maxilla and posterior mandible

3. Implants coated with hydroxyapatite are indicated

Dental examination…

• Fine trabecular bone (d4) BIC = < 25 %

1. No cortical crestal bone2. posterior maxilla in long term

edentulous patients

CONTRAINDICATIONS

Absolute Contraindications For Implant Treatment

• High dose irradiated pt

• Patient with psychiatric problems

• Systemic Hematologic disorders

Relative Contraindications

• Pathology of hard or soft tissues

• Recent extraction sites

• Patient with drug, alcohol or chewing tobacco

• Low dose irradiated patient

Posterior Single Tooth Implant

local contraindications for a posterior single tooth implant

indications for a posterior three unit fpd

inadequate bone volume faciopalatal < 5 mm mesiodistal < 6.5 mm

inadequate bone volume inadequate intertooth space < 6.5 mm lack of intertooth boney height

Moderate to advanced mobility of 2 – 4 adjacent teeth

Adjacent teeth are mobile

Limited time for patient treatment Reduced time of treatment

Limiting Factors For Anterior Single Tooth Implant

Age Limitations

• Growth and development may be affected by an implant as it may act as an ankylosed tooth.

• As a general rule, implant insertion is delayed for female patient till atleast 15 years and in male patients until 18 yrs of age.

Mesio-distal Space• A traditional 2 piece implant

Should be atleast 1.5mm from an adjacent tooth. When the implant is closer than this, any bone loss will cause the implant and the adjacent tooth to lose bone rapidly.

• This will compromise the inter-proximal aesthetics and sulcular health of the implant and the natural teeth.

Bone height• The ideal mid-crestal position of the edentulous site should be 2mm apical

from the facial CEJ of the adjacent teeth.

• When the bone crest is above this, a bone graft procedure may be performed.

• The inter-proximal bone should be scalloped 3mm more incisal than the mid-crestal position.

Challenging Aesthetics

• Cross sections of teeth are not round and are often larger in facio-palatal dimensions.

• The cervical emergence profile of a crown on a round implant needs to be created prosthetically.

Crown Height Space

• The implant abutment will be too short for the proper retention.

EVIDENCE BASED STUDIES ON IMPLANT DENTISTRY

Do implant retained or supported dentures improved masticatory performance???

-Fueki K, Kimoto K, Ogawa T, Garrett NR published inJ Prosthet Dent. 2007 Dec; 98(6):470-7.

Results • 18 articles met the criteria for inclusion. Experimental studies showed:1. fixed implant-supported partial dentures do not provide significant

improvement in masticatory performance compared to conventional removable partial dentures for Kennedy Class I and II partially edentulous

mandibles.2. the combination of a mandibular implant-supported or retained

overdenture (IOD) and maxillary conventional complete denture (CD) provides significant improvement in masticatory performance compared to CDs in both the mandible and maxilla for a limited population having persistent functional problems with an existing mandibular CD due to severely resorbed mandible.


-Fueki K, Kimoto K, Ogawa T, Garrett NR.

Results…3. the type of implant and attachment system for mandibular IODs has a

limited impact.

• Well-designed, experimental studies showed ; i. mandibular fixed implant-supported complete dentures provide

significant improvement in masticatory performance compared to mandibular CDs in subjects dissatisfied with their CDs; and

ii. implant-supported mandibular resection dentures have an advantage

over conventional dentures in masticatory performance on the defect side of the mouth.


-Fueki K, Kimoto K, Ogawa T, Garrett NR…...

Conclusions • While a number of studies on masticatory performance have

been conducted in patients with various designs of implant-supported or retained dentures, high-level evidence supporting advantages in masticatory performance of implant-supported or retained dentures over conventional dentures is limited.


-Fueki K, Kimoto K, Ogawa T, Garrett NR…...• Moreover, two RCTs that compared IOD with new complete dentures

concluded that IOD enhanced the masticatory improvement compared with conventional complete dentures. This difference reached statistical significance at 1 year follow-up.

• In conclusion, subjects with low ridge or severe ridge resorption profit from implant-supported overdentures by increased masticatory performance and totally edentulous patients profit from fixed implant-supported complete denture from a masticatory point of view in general.

• Finally, it must be kept in mind that masticatory performance based on the ability of the subjects to chew hard food is only a part of oral health related quality of life. Other factors such as, satisfaction with treatment and oral confidence of the subjects also play a major role.

Recent AdvancesRecent Advances

Immediate Function Implants

• Today, modern implant design and the use of 3D CAT Scans allow experienced dental professionals to insert the implants, and immediately place the new teeth on the implants. Research has shown that when properly applied, this one-stage approach results in as good or better implant success rates as the traditional two-stage approach.

• Benefits of Immediate Function● Shortened treatment time (it is possible to go from tooth loss to

having functionaland aesthetic teeth in one treatment session),● Better clinical efficiency,● Greater patient comfort,● The elimination of bone grafts and sinus lifts, and● Patients always leave with teeth!

All – on – 4 Implant

• The All-on-4 Dental Implant Procedure uses four implants, with the back implants angulated to take maximum advantage of existing bone.

• Special implants also were developed that could support the immediate fitting of replacement teeth.

• This treatment is attractive to those with dentures or in need of full upper and/or lower restorations.

• With the All-on-4 Procedure, qualified patients receive just four implants

and a full set of new replacement teeth in just one appointment—without bone grafts!

•All four titanium implants are placed so that the bone will grow around and secure them in place

•With only four implants, there is much less invasive and lengthy surgery.

•Once the implants are in place, the Oral Surgeon attaches abutments to which the new replacement teeth can be secured.

•The Prosthodontist fits the replacement teeth on the abutments and adjusts the bite for comfort and a beautiful smile

Interdenatal Esthetics• A number of cases show deficiency of papilla in the interdental

papilla between the implant or between implants and teeth, which poses an esthetic problem.

• This is counteracted by injection of hyaluronic acid, commonly available as Restylane.

• Its effect lasts for 6 – 24 months after which a new dose is administered.

Conclusion• Appropriate case selection, good occlusal harmony, careful

management of hard and soft tissues, and maintainance of oral hygiene all contribute the success and predictability of dental implants.

• All health care proffesionals, today are compelled to become knowledgeable in all aspects of dental implant therapy and continue their education as new information and evidence becomes available. Thus implants can truly be regarded as the…

“BRIGHT FUTURE OF PROSTHODONTICS” !!

References• Contemporary implant dentistry- Carl Misch• Osseointegration and occlusal rehabilitation- Sumiya Hobo• J Prosthet Dent. 2007 Dec; 98(6):470-7.

Education

Implants the future of prosthodontics