INTRODUCTION TO CONTEMPORARY DENTAL IMPLANTOLOGY

Dr. Mohamed A. Fouda BDS, MSc

Cairo UniversityPeriodontist

Prosthetic Options in Dentistry

Why Dental Implants?

• It Maintains Bone Volume.

• Bone needs stimulation to maintain its form and density.

• Loss of teeth leads to loss of width then height of the bone.

• After one year 25% of width and up to 4 mm of height will be lost.

TODAY THE PROFESSION MUST CONSIDER NOT ONLY THE LOSS OF TEETH BUT ALSO THE LOSS OF BONE.

• It Maintains Bone Volume.

• Preservation Of Adjacent teeth.

• Natural Emergence Profile.

• Increases stability and Retention.

• Reduce Removable prosthesis size.

What is a dental implant ?

• A dental implant is an artificial tooth root replacement and is used in prosthetic dentistry to support restorations that resemble a tooth or group of teeth.

Sub-periosteal Implants

Trans-mandibular implants

Ramus frame Implant

Mucosal inserts

Blade implants

Root Form Implants

Osseointegration

Osseointegration is defined as “a direct structural and functional

connection between the ordered living bone and the surface of the

load carrying implant” (Branemark, 1983).

Bone has been shown to be

approximately 20 nm away from the implant surface when

examined with the electron microscope (Albrektsson, 1985).

Branemark

The Edentulous Alveolar Ridge

• The formation and the continued preservation of alveolar ridge is dependant on the continued presence of teeth.

• Also the shape of teeth is an important factor in determining the shape of the alveolar process.

Thick tissue biotype subjects have short and wide teeth

Thin tissue biotype subjects have long and narrow teeth

Effect of tooth loss on the alveolar ridge

Bone loss is more pronounced on the buccal aspect than the lingual/palatal aspect of the ridge

CLASSIFICATION OF REMAINING BONE

A& B Substantial amount of alveolar bone remains

C, D & E Minute amount of alveolar process remains

Lekhom and Zarb (1985)

CLASSIFICATION OF BONE DENSITYCARL MISCH

Topography of the alveolar process

MACRO DESIGNIMPLANT MATERIALS

Commercially Pure Ti Ti Alloy Zirconia

Titanium 6AL-4V

• Titanium implants are biocompatible due to the formation of an oxide layer on their surface which is resistant to corrosion and have hydrophilic properties (Hansson et al 1983), When exposed to air, Titanium forms an oxide layer immediately that reaches a thickness of 2 to 10 nm by 1 sec and provides corrosion resistance (Ducheyne 1988; Donley and Gillette 1991).

• Because of the high passivity, controlled thickness, rapid formation, ability to repair itself instantaneously if damaged, resistance to chemical attack, catalytic activity for a number of chemical reactions and modulus of elasticity compatible with that of bone of titanium oxide, Titanium is the material of choice for intraosseous applications (Parr et al 1985; Kasemo and Lausmaa 1985).

TWO-PIECE Vs. ONE-PIECE

MINI IMPLANTS

CYLINDRICAL Vs. TAPERED

• The original endosseous implants were cylindrical (parallel) in design, although this design was proven to be successful, it was not suitable for all applications. One of the most obvious limitations of its use is narrow ridges and ridges with concavities as there is an increased risk of perforation in the labial bone (Garber et al 2001).

• The introduction of tapered implants resulted in improved esthetics and easier placement between the adjacent natural teeth as it resembles more closely the shape and taper of the original teeth roots (Shapoff 2002) , also it has the ability to accommodate the shape of thin ridges and ridges with labial concavities more than cylindrical implants (Garber et al 2001).

• The theory behind the use of tapered implants is to provide for a degree of compression of the cortical bone in a poor implant site, tapered implants distribute forces into the surrounding bone, thereby creating a more uniform compaction of bone in adjacent osteotomy walls compared with parallel walled implants. Thus when inserted, it creates lateral compression of bone (O’sullivan et al 2004).

TYPES OF IMPLANT-ABUTMENT CONNECTIONS

External Hex

Internal Hex

Internal Taper

Morse Taper

Morse taper refers to a taper of 5/8ths of an inch

per foot

Spline

Cover Screw

Implants Threads

• Threads are added to the implant body and are used to:

1. maximize initial contact between the implant and bone

2. To improve initial stability3. To enlarge implant surface area4. To favor dissipation of interfacial stress.

MICRO ANATOMY

• The original studies on osseointegration were performed using turned (machined) surface implants. Efforts to enhance implant surface technology have focused on improving the predictability, rate, and degree of osseointegration.

• Until now, there is no consensus concerning the most appropriate implant surface topography (Raghavendra et al 2005).

• Some important advantages have been attributed to increased surface roughness. These include increased surface area of the implant adjacent to bone, improved cell attachment to the implant surface, increased bone present at the implant surface, and increased biomechanical interaction of the implant with bone (Cooper 2000).

SURFACE TREATMENT

Addition:

1- HA Coated

2- TPS

SURFACE TREATMENTSubtraction:

1- Acid etching

2- Acid etching and Grit blasting

•Edentulous ridge (Branemark 1952) 60 years of research

•Single tooth replacement 41 years of research

•Immediate tooth replacement 34 years of research

RELATIVE CONTRAINDICATIONS•Age

•Patient’s general health

•Smoking

•Patient psychology and motivation

•Availability

ABSOLUTE CONTRAINDICATIONS

•Drug or Alcohol abuse

•Psychological

•Debilitating or uncontrolled disease

PERIODONTAL THERAPY VS. IMPLANT THERAPY

The 0, 5, 10 years rule

• Included in treatment plan

• Can be joined to implants

• Extraction and site development

• Independent implant restoration.• If adjacent to an edentulous site consider reducing

the prognosis

EXAMPLES•Smokers moderate and sever Periodontitis extraction and dental implant placement (implant is in direct contact with bone less effect from smoking)

•Unsuccessful treatment with progressive bone loss When remaining bone is 10 mm extraction (minimum predictable implant length 10 mm).

•Grade III Furcation involvement Implants is more predictable than root amputation and hemi sectioning.

•Mobility mobile teeth are poor in terms of load carrying and should be removed.

MUCOSA AT TEETH AND IMPLANTS

Microphotograph of a cross section of the buccal and coronal part of the periodontium of a mandibularpremolar. Note the position of the soft tissue margin (top arrow), the apical cells of the junctional epithelium (center arrow) and the crest of the alveolar bone (bottom arrow).The junctional epithelium is about 2 mm long and thesupracrestal connective tissue portion about 1 mm high.

Microphotograph of a buccal–lingual section of the peri-implant mucosa. Note the position of the soft tissue margin (top arrow), the apical cells of the junctionalepithelium (center arrow), and the crest of the marginal bone(bottom arrow). The junctional epithelium is about 2 mm long and the implant–connective tissue interface about 1.5 mm high.