Edentulous Maxilla Fixed Prostheses Options

7. Edentulous Maxilla - Fixed Prostheses

John Beumer III DDS, MS
Hiroaki Okabe CDT
Jungo Endo CDT
Division of Advanced Prosthodontics, Biomaterials and
Hospital Dentistry, UCLA
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Edentulous Maxilla - Fixed Prostheses
Patient selection and treatment planning based on:
v  Biomechanics
v  Resorptive patterns and jaw relations
v  Lip line
v  Cost
v  Patient compliance

Fixed prostheses – Edentulous Maxilla
Issues to Consider
•  Resorption pattern and maxillomandibular relationships
•  Sinus architecture
•  A-P spread
•  Esthetics
•  Lip line
•  Phonetics and Hygiene
•  Hygiene access vs speech articulation vs compliance
•  Economics
•  Technical Challenges
•  Expertise of lab personnel
•  Implant placement
•  Passively fitting castings

Definitions
Implant supported prosthesis - All the
forces of occlusion are borne by the implants.
Can be either fixed partial dentures or
removable overlay dentures.

Implant assisted prosthesis – The forces of
occlusion are shared between the implants and
the mucoperiosteum. Always removable
overlay dentures.

Implant Supported Prostheses - Biomechanics
Edentulous maxilla
Minimum requirements from a biomechanical
perspective
v  Six or more implants
v  Minimum of 2 cm of A-P spread
v  Distal implant must be at least 10 mm in length

Few patients qualify and if these conditions cannot
be met implant assisted designs are recommended.

Implant Supported Prosthesis
Arrangement of implants
"  Maxilla - Anterior-Posterior Spread required for implant
supported prosthesis - 2 cm or more

Less than the above
dictates use of an implant A-P
Spread
assisted prosthesis

Maxilla - Pattern of resorption.
Following extraction, resorption is from buccal-
labial towards the lingual.

Labial
plate

Fixed Prostheses - Resorptive patterns
and Maxillo-mandibular Relationships
The normal patterns of
resorption result in pseudo
class III jaw relations.

In these situations Overdentures
(either implant supported or
implant assisted) are preferred
over fixed prostheses. Why?

Removable overlay dentures with properly extended and contoured
denture flanges provide better lip support and facial contours.

Fixed Prostheses - Resorptive patterns
and Maxillo-mandibular Relationships

v  Favorable jaw
relations and
alveolar ridge
contours
v  This patient is a
good candidate for
fixed.

Fixed - Resorption pattern
and maxillomandibular relationships
v  Following extraction of maxillary
teeth the labial surfaces of the
alveolar process resorb creating a
pseuodo Class III jaw relationship in
most patients.

" If such patients are restored with
fixed, the labial surfaces of the
anterior teeth are far anterior to
the labial contours of the alveolar
ridge.

" Result: Inadequate
support for the upper lip.

Esthetics - Lip Support
Fixed vs Removable
"   Fixed in retrospect was a poor choice
"   As the patient aged and lost tonus of
the lip musculature lip contours became
deficient

Implant supported fixed prosthesis
Patient selection – Jaw relations

Jaw relations:
Labial surfaces of the anterior teeth
should be on the same plane as the
alveolar ridge if lip contours are to
be restored with a fixed prosthesis.

Ideal patient would present with following
clinical findings:
" Favorable jaw relation
" Low lip line
" Minimal sinus pneumatization
" Compliant

Patient selection – Lip line

This patient presents with a high lip line. The best
esthetic result would be attained with an implant
assisted overdenture or a fixed detachable prosthesis.

Fixed
Patients with unfavorable jaw relations
The speech vs hygiene access dilemma
v  If you close the spaces and provide lip support access for
oral hygiene is compromised
v  If you provide hygiene access, you compromise lip
support and speech articulation

Fixed
The speech vs hygiene access dilemma
v  If
you close the spaces and provide lip support
access for oral hygiene is compromised

" If one incorporates a ridge lap into the design, these esthetics
and phonetic difficulties are resolved but at the expense of
hygiene access. Note the accumulation of plaque beneath this
fixed hybrid prosthesis.

Phonetics and esthetics vs hygiene
access

Fixed vs removable
" Much easier to clean beneath tissue bar than
beneath fixed partial denture

Fixed and Sinus Pneumatization
Often, even though a patient may be a good candidate
for fixed, pneumatization of the maxillary sinuses may
preclude placement of implants far enough posteriorly
to achieve sufficient A-P spread. Options:
v  Sinus lift and graft
v  All on four
v  Angled implants
v  Zygomatic implants

Sinus lift and graft

v Provides bone sites in the posterior maxilla.
v This is a predictable option

All on Four

Issues of concern
v  Short implants in the distal positions
v  Cantilevers

All on Four with axial angulation

Problems
v  Implant overload and loss of the distal implants
v  This option is not predictable and not recommended

Angled Implants

v Posterior implants parallel to the anterior wall of the sinus
v Longer implants with better primary stability
v Distal implants exit more posteriorly eliminating cantilever

Angled Implants
v Long implants in native bone
v  Better initial primary stability
v  Optimization of anterior posterior-spread
v  Elimination of the cantilever.

Angled Implants

Up-right = Cantilever vs Tilted= No Cantilever
Bevilacqua M, Tealdo T, Menini M, Pera F, Ravera G, Drago C, Pera P.
The influence of cantilever length and implant inclination on stress
distribution for maxillary implant-supported full-fixed prostheses.
J Prosthet Dent 2010 (In submission)

Angled Implants

Concerns
Long term followup is lacking

24 months X-Ray follow-up

Tealdo T, Bevilacqua M, Pera F, Menini M, Ravera G, Drago C, Pera P
Immediate function with fixed implant-supported maxillary denture: a 12-
months pilot study
Journal Prosthetic Dentistry 2008; 99:351-360.

36m X-ray follow-up

Tealdo T, Bevilacqua M, Pera F, Menini M, Ravera G, Drago C, Pera P
Clinical and radiographic outcomes of immediate versus delayed loading of
dental implants in edentulous maxillae: a 36-months prospective study.
International Journal of Prosthodontics 2010. Accepted for
publication.

Zygomatic Implants
v  Introduced by P. I. Branemark in the 1980’s as an
alternative to bone grafting in patients with pneumatized
maxillary sinuses
v  They are designed to be used in concert with 4 axially
placed implants in the premaxilla.
v  Success rates have been above 90% in almost all clinical
reports (Branemark et al, 1998; Aparicio etal, 2006;
Bedrossian et al, 2006)

Zygomatic Implants

v  Implants are splinted
together with rigid metal
frameworks.
v  This is a PFM fixed
prosthesis.
v  Note the metal occlusal
surfaces

Zygomatic Implants
Complications
v  Zygomatic implants exiting on the palatal side may limit
the tongue space an affect speech articulation
v  Oronasal fistula formation
v  Periorbital hematoma
v  Penetration into the orbit
v  Facial swelling

Types of Fixed Prostheses

PFM fixed prosthesis Fixed Hybrid Prosthesis

Fixed hybrid prosthesis
v Metal framework, denture teeth and pink acrylic resin

PFM fixed prosthesis
v Porcelain fused to metal with the ginigival contours
restores with pink porcelain

Fixed Hybrid Prosthesis

Fixed hybrid prosthesis
This design was used frequently in the 80’s. Note the
spaces beneath the bridge. These spaces facilitate
hygiene but during speech air escapes through these
spaces adversely affecting speech articulation.

Today, we fabricate maxillary fixed restorations with
porcelain fused to metal restorations and attempt to
close these spaces consistent with hygiene access

Candidates for fixed prosthesis
demonstrate
v Favorable jaw relations
v Minimal resorption with little sinus pneumatization
v Low smile and laugh line

Minimum requirements for Fixed Prostheses

Implant numbers and position
v  Minimum number - 6 implants
v  Minimum of 2cm of A-P spread
v  Implants must be placed in tooth positions

v  If
possible screw access holes for the implants should
exit the cingulum area of the anterior teeth and through
the center of the occlusal table of posterior teeth.

Candidates for fixed prosthesis
demonstrate
" Smile line – If high overdenture is preferred
" Lip support – If required overdenture is preferred

Surgical templates

Design criteria
v  Based on a diagnostic wax-up or a duplication of the
existing denture of the patient.
v  Palate retained for accurate positioning
v  Lingual portion removed

Clinical case presentation
Patient was treatment planned to receive an implant
supported fixed partial denture

Design Principles
v  Custom abutments or custom substructures as needed
v  No ridge laps in the posterior segments
v  Prosthesis is made in segments
v  Screw retained

Impressions and making
master casts

A soft tissue cast is made to
represent gingival contours. It
should be detachable from the
master cast.

Full Contour Wax Pattern

Ucla abutments with resin pattern sleeves are
secured to the fixture analogues in the master
cast.

Full Contour Wax Pattern

v A full contour wax pattern is
developed from. Note that
several of the implants
demonstrate excessively labial
inclination.
v The desired contours are
recorded with a silicone
template. This will be used later
to verify the wax-cut back

PFM Fixed Prosthesis
Wax cutback is completed and the custom abutments
are milled to a 3 degree taper

Note the channels
developed for the
lingual retention
screws.

Custom abutments and substructures

v  Milling is refined in metal using a milling machine

v  Custom abutments are polished and verified
intra-orally

v  Additionalexamples of custom substructures.
v  They are milled to a three degree taper.
v  There must be hygiene access beneath the
substructures

Super structures
v  Wax pattern for metal framework (super structure) for
PFM restoration is then developed

Note the channels for the lingual retention screws.

Super structures

v  Completed metal
framework (super structure)
for anterior segment of the
PFM fixed prosthesis.
v  The lingual retention screw
channels are tapped.

Super structures

Before adding the porcelain check to see that the metal cut
back was sufficient to add porcelain of desired contour and
thickness

Super structures
v  Metal framework
elements are tried
in position and
solder relation
records made to
correct for
discrepancies in fit.


" Completed
prosthesis
" Note the custom
abutments
(arrows)


v  Completed and assembled
fixed partial denture

Occlusion
v  Opposing fixed hybrid prosthesis – Group
function

Right working Left working

Inserting the prosthesis

v Healing abutments are
removed
v Posterior segments and the
custom abutments are
secured with gold screws
v The anterior segments are
screwed into position

l  Inserted restoration
l  Occlusion is
designed for group
function
l  Note the hygiene
access

" Completed prosthesis
" Note lip line during high smile

Oral hygiene
is facilitated
with
superfloss


14 year followup.
Denture teeth of the
mandibular fixed hybrid
prosthesis have been
replaced once.


v  Anterior segment secured
v  Note the rigid type tube lock attachments (arrows).
The posterior segments will be attached to the
anterior segment by means of these rigid
attachments


Right working position

Occlusion
Anterior guidance

Ridge lap design with pink porcelain

Fixed Detachable Prosthesis
(Implant supported overdentures)

Indications
v  Patient wants a fixed type prosthesis
v  Patient presents with significant resorption of the
maxilla and requires a denture flange
v  Patient presents with sufficient bone for placement of
at least 6 implants with 2 cm of A-P spread


" This patient has sufficient numbers of implants (6) placed
with sufficient A-P spread (minimum 2cm) to permit
fabrication of an implant supported overlay denture.

" Master impression is border molded in order to record the
thickness of the labial and buccal denture flange necessary to
provide appropriate support for the upper lip.

Transfer impression copings (closed tray) were used an the
corrected impression made of polysiloxane.

v  The cast is surveyed to determine the proper path of insertion
v  Tissue bar is milled to 3 degree taper
v  The bar must fit within the contours of the denture without
compromising palatal contours or tooth positions.

Tissue bar designs
v  The 3 degree taper provides excellent stability
and facilitates retention
v  Hader and Locator attachments, because of their
low profiles, are used for attachments

Locator attachments Hader attachments Hader attachments

Super structures
with “Hader” clips
inserted

" A metal superstructure is fabricated to house the
attachments, precisely engage the milled tissue bar and
provide rigidity to the prosthesis

In this patient Hader
attachments were used.

The completed prosthesis

"The metal superstructure contains the clip housings and also
provides rigidity to the prosthesis. Since there is virtually no
movement of the overlay denture during function there is very little
wear of the plastic Hader clips. They need replacement every
three to five years.

Rentention bar and prosthesis in position

Occlusion:
Group function
Note: Opposing arch is composed of
implants supported fixed partial
dentures and natural dentition

" The master cast must be surveyed to account for the alveolar undercuts and
identify the proper path of insertion.
" This design also uses Hader attachments. They are used because of their
low profile and because they are easily replaced when needed.
" The distal Hader clips are parallel to the anterior clips and located between
the last two implants. The bar is milled to a 3 degree taper using a milling
machine.

Metal superstructure. Metal
housings are placed on the bar and
the wax pattern is developed. The
metal is cast to these metal
housings.


Completed prosthesis
v Occlusion is lingualized with bilateral balance.
Note:
v The fixed in the mandible was redone in order to idealize
the plane of occlusion and opposing tooth contours.
v Close patient followup is mandatory. Given that the
opposing dentition is restored with implant supported fixed
partial dentures with porcelain occlusal surfaces rapid wear
of the posterior denture teeth and of the overlay denture
and loss of VDO should be anticipated.

12 year followup

v  Note the occlusal wear and the
slight loss of vertical dimension
of occlusion
v  Erythematous tissue beneath
the tissue bar

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on Complete Dentures, Implant Dentistry,
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Edentulous Maxilla Fixed Prostheses Options

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