Prosthetic Options in Implant Dentistry

Rola Shadid, BDS, MSc, AFAAID

Seminar Outline

· Description of implant prosthesis designs

· Selection criteria

Ideal goal of implant dentistry to

replace patient’s missing teeth to normal contour, comfort, function, esthetics, speech and health, regardless of previous atrophy, disease or injury of the stomatognathic system

Final restoration – not implants

The end result should be clearly identified before the project

begins

Ideal Treatment Plan Sequence The prothesis first is planned The key implant positions and implant

number are selected The patient force factors The bone density Implant size Implant design Available bone in the edentulous site

· Biologically-driven implant placement

· Prosthetically-driven implant placement

· Completely edentulous prosthesis design

· Partially edentulous prosthesis design

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ADVANTAGES OF FIXED IMPLANT RESTORATIONS

1. Feeling and acting simillar to natural teeth2. Removable implant overdentures require greater maintenance and exhibit more complications than fixed restorationsProblem of IODs in review of litrature by Goodacare: Retention and adjestement problem(30%) Clip or attachment fracture(17%) Fracture of prosthesis (12%) Reline(19%)

3. Mandibular overdenture often traps food below its flanges4.Important role for the presence of complete implant supported restoration is the maintenance and regeneration of posterior bone in mandible

Prosthesis Designs

ln 1989, Misch proposed five prosthetic options for implant dentistry:

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FP-1· Replace only the anatomical crowns· Minimal loss of hard and soft tissues· The bone and soft tissue must be ideal in volume and

position to obtain an FP-1 for the final restoration· Very similar in size and contour to most traditional fixed

prostheses· Most often desired in the maxillary anterior region

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FP-1

FP-1 is difficult to achieve when more than two adjacent teeth are missing

36% of patients presented bone deficiencies that hindered

prosthetically ideal placement of Implants

Bone & soft tissue augmentation is often required

Andersson et al. 1995

FP-1 Material

Porcelain to noble-metal alloy

Zirconia-based restoraion

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FP-21. Restore the anatomical crown & a portion of the root

2. The volume and topography of the available bone is more apical

3. Incisal edge in correct position, but gingival third of crown is overextended.

3. Are similar to teeth exhibiting periodontal bone loss and gingival recession

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The patient and the clinician should be aware from the onset

of treatment that the final prosthetic teeth will appear longer than healthy

natural teeth without bone loss

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Esthetic zone vs FP-2

· The smile/lip line should be evaluated· The selection of FP2 or FP3 is often based

on the evaluation of the lip line.· An FP2 (in low lip line patients) is easier to

fabricate because of fewer porcelain bake cycles.

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Smile Line Classification

· High: display all of the interdental papilla and more than 2 mm of tissue above the cervices of the teeth. Prevalence is 11%

· Average: 75% to 100% cervicoincisal length of maxillary anterior teeth and interdental papilla exposed. (69%)

· Low < 75% cervicoincisal length of maxillary anterior teeth exposed. (20%)

Smile Line Classification

Average High

Low

FP-2

If lip line during smiling does not display cervical regions, longer teeth are usually of no esthetic consequences, provided pt is informed

If lip line during smiling does not display cervical regions, longer teeth are usually of no esthetic consequences, provided pt is informed

FP-2 Material

Porcelain to noble-metal alloy

Easily be separated and soldered in case of a nonpassive fit at the metal try-in

Noble metals in contact with implants corrode less than nonprecious alloys

Zirconia based restoraion

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FP-3Replace the natural teeth crowns and has pink-colored restorative materials to replace a portion of the soft tissue

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FP-3

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Normal to high maxillary lip line during smiling, or pt with high esthetic demands

Materials for Full Arch FP-3

Porcelain-metal with pink porcelain Hybrid restoration of denture teeth and acrylic and metal

substructure Zirconia based restoration

The primary factor that determines the restoration material is the amount of crown height space

<15mm ≥15mm PORCElAIN–METAL HYBRID

CHS

Excessive CH & traditional porcelain-metal restoration ???

· Porcelain thickness should not be greater than 2-mm thick

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large amount of metalNoble metals

Base metalsMore shrinkage

porosities in the structure

increases the risk of porcelain fracture

weight and cost

Fixed detachable hybrid prosthesis (fixed complete denture) ( CHS ≥15mm)

A smaller metal framework and the acrylic resin polymerized with the denture teeth on the framework.

Fixed detachable hybrid prosthesis

The denture teeth in these prostheses should not be acrylic or composite, owing to a high fracture rate. Instead, porcelain denture teeth are suggested.

Fixed detachable hybrid prosthesis

1. Smaller metal framework

2. Denture teeth and acrylic

3. Less expensive to fabricate

4. Highly esthetic

5. Acrylic pink soft tissue replacements

6. The impact force of dynamic occlusal loads is reduced

7. Lightweight

8. Easier to repair9. 15 to 20 mm

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Fixed detachable hybrid prosthesis

The fatigue of acrylic is greater than the traditional prosthesis

REPAIR of the restoration is more commonly needed

CAD-CAM zirconia-based, screw-retained, cross-arch restorations

Zirconia framework veneered with porcelain

Full-contour (monolithic) Zirconia restorations

CAD-CAM zirconia-based, screw-retained, cross-arch restorations· lack of casting distortion due to the CAD/CAM

process; · highly reduced chance of chipping compared to

acrylic or porcelain· stronger and improved aesthetics of screw

access hole areas. · monolithic zirconia bridge requires only 12 to

15 mm of prosthetic space, not 15mm-20mm

The success rate of implant supported screw-retained zirconia prostheses have been shown to be as high as 100% for a period of 5 years

Vizcaya, 2011; Oliva, 2012

· High level of accuracy and rigidity of the framework was obtained by CAD-CAM method, and satisfactory esthetics was featured by layering the porcelain on the Zirconia framework.

Hong et al. 2014

Removable Prostheses

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Removable Prostheses

Complete removable overdentures have often been reported with predictability

Two kinds of removable prostheses, based upon support of the restoration:

1. RP-4

2. RP-5

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RP-4· Completely supported by the implants· The restoration is rigid when inserted· A low-profile tissue bar or superstructure that splints the implant

abutments· 5 or 6 implants in the mandible· 6 to 8 implants in the maxilla

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RP-5· Implant and soft tissue support

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RP-5· The primary advantage of an RP-5 restoration is the reduced

cost· Bone will continue to resorb in the soft tissue-borne regions· Bone resorption with RP-5 restorations may occur two to

three times faster than the resorption found with full dentures· Relines and occlusal adjustments every few years

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Selection Factors for Completely Edentulous

· Patient’s desire· Financial capabilities· Number of implants placed· The amount of vertical resorption (Crown

height space)· Labial support requirements. (The

amount of Maxillary anterior/posterior resorption)

The amount of vertical resorption (Crown height space)

· CHS <15mm (Fixed)

· CHS ≥15mm (Fixed hybrid or Removable)

· If CHS < 12 mm, overdenture is contraindicated without osteoplasty

CHS for Removable

CHS for Fixed

Maxillary Anterior/Posterior Resorption

· If the anterior/posterior (A/P) resorption is 7 mm or less, fixed prostheses are probably indicated

· If the A/P resorption is in the range of 8 to 10 mm, fixed or removable prostheses may be indicated

· If the A/P resorption > 10 mm, removable or fixed prostheses with removable labial veneers

Carl Drago, 2011

Maxillary Anterior/Posterior Resorption

References

· Prosthetic options in implant dentistry (chapter 5), Contemporary Implant Dentistry, 3rd Edition, Carl Misch

· Drago C, Carpentieri J. Treatment of maxillary jaws with dental implants: guidelines for treatment. J Prosthodont. 2011 Jul;20(5):336-47.