What Comes After

All on Four?

Michael J. Maginnis, D.D.S., M.S.Board Certified Specialist

Removable Prosthodontics

Author’s Note:

The following is one method of completing the surgical and prosthetic treatment known as

“All-on-Four”. The technique involves removal of all of the remaining teeth, placement of

at least four dental implants, some of which are angled to avoid structures such as the

mental nerves and the maxillary sinuses. Records are made of the implant positions for

fabrication of milled bars that will support and retain the final prostheses. Meanwhile,

immediate denture prostheses are affixed to the implants. The surgery, records and

delivery of the immediate prostheses are completed in one day. Approximately four

months later, the milled bar and the final denture prostheses are delivered.

My concern, as a prosthodontist, is that if the implants fail and cannot be replaced, then

the large amount of alveolar bone that was removed during surgery to make room for the

implant abutments and milled bars may eventually create a class of “dental cripples”.

The cases used in this report to illustrate severely atrophied maxillary and mandibular

ridges were caused, for the most part, by periodontal disease or poorly fitted prostheses

and not by implant surgery, per se. They do, however, illustrate the difficulty in treating

patients with gross bone loss, regardless of the reason.

Dr. Michael J. Maginnis, D.D.S., M.S.,

Board-Certified Specialist, Removable Prosthodontics.

All-on-FourDr. Paulo Malo’s:

Dentate Patient

Maxillary Bone Reduction

18 mm

A word of caution: A set of complete dentures needs approximately

18 mm of interarch space. Implant bars and their supporting

abutments need another 5 to 6 mm of space per arch.

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When constructing traditional immediate

dentures, along with teeth, only a minimal

amount of bone and tissue is removed.

With All-on-Four (or Six) more bone must

be removed to accommodate implant

abutment heads and milled bars.

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If an insufficient amount of

bone is removed, the denture

prosthesis has to be very

thin…and fragile….to

accommodate a milled bar

and implant abutments.

During All-on-Four surgery,

measurements are made to assure

10 –12 mm of space for implant

abutments, milled bar , acrylic base

and denture teeth.

10 – 12 mm

CEJ

To accommodate a milled

implant bar and the supporting

abutments, 5 to 6 mm of bone

must be removed above the

cemento-enamel junction of the

extracted teeth.

CEJ

5 – 6 mm

A clear bone reduction guide is used to

verify that 5 to 6 mm of bone has been

removed above the cemento-enamel

junction of the extracted teeth to

accommodate a milled implant bar and

its supporting implant abutments.

Angled Abutment

Selection and Orientation.

The clear bone reduction guide is

used to verify that the abutments are

within the outline of the planned

prosthesis and that the angled

abutments are parallel to the

planned path of insertion.

White temporary cylinders are seated

on each abutment and secured with an

abutment screw. The cylinders will be

used to transfer the position of the

abutments to a working model.

Following removal of all teeth,

the mandibular ridge is being

prepared for bone reduction to

accommodate a milled implant

bar and its supporting

abutments.

When constructing a bone

reduction guide, reduce height

of lower cast to allow for 12

mm of space between upper

incisor edge and top of

implant.

Following removal of the teeth,

the alveolar ridge is reduced in

height 5 to 6 mm below the

cemento-enamel junction to

accommodate the milled implant

bar and supporting abutments.

The mandibular bone reduction guide is

held in place against the maxillary bone

reduction guide with bilateral ball clasps.

The pre-operative vertical dimension of

occlusion is used to verify that adequate

boney height has been removed to

accommodate the milled implant bar and

supporting abutments.

Implant Placement

Angled Abutment

Placement

Blu-Mousse bite registration

material by Parkell, Inc. is

placed in the alveolar section

of the immediate denture and

is used to record the position

of the temporary cylinders.

The denture prosthesis is

firmly seated in the palatal

vault and held until the

registration material sets.

Position of each

temporary cylinder is

recorded in the set

registration material.

Openings are cut

in the lingual

surface of the

denture prosthesis

to allow for pick -

up of transfer

impression

copings.

Transfer impression

copings are picked up

with self-curing acrylic

resin, two at a

time…anterior first.

Self-curing acrylic resin is injected

into the space around the transfer

impression copings. The denture

prosthesis is held in place until the

resin has cured. The procedure is

then repeated for the two distal

transfer copings.

Openings are cut in the occlusal

surface of the denture prosthesis

to allow for pick-up with self-

curing acrylic resin of the two

distal transfer impression

copings.

With the maxillary denture

secured to the implant

abutment heads, the

mandibular denture can be

secured in a centric occlusion

position with ball clasps. An

accurate transfer of the

position of the mandibular

implant abutment heads can

now be accomplished.

White temporary cylinders

screwed in place on the

mandibular implant abutment

heads.

Blu-Mousse bite registration

material is placed in the

alveolar section of the

immediate denture and is

used to record the position of

the temporary cylinders.

The mandible is held in centric

occlusion position and the pre-

surgical vertical dimension of

occlusion is verified.

Position of each

temporary cylinder is

recorded in the set

registration material.

Attach impression copings to lower denture with

self curing acrylic. As with the maxillary

denture….two at a time, anterior first..

The immediate dentures with

the attached impression copings

are now ready for conversion in

the laboratory to interim

prostheses that will be worn by

the patient during the three to

four month healing period.

In many instances, to

assure better support, five

or six implants are placed,

particularly in the maxilla.

Implant analogs are placed in

the impression copings and

secured with wax prior to

pouring a master cast.

Master cast, with

conversion prosthesis

cleaned of bite

registration material

and prepared for

laboratory reline in

self curing acrylic

resin.

All in one day

All-on-Four

During the three to four month

healing period, milled titanium bars

are fabricated on the master

implant abutment models.

Sufficient space is left between

the bar and the tissue surface

of the model to allow for final

acrylic denture resin to be

wrapped around the bar.

In the final stages of treatment, the

milled bar is tried in to verify fit and a

final prosthesis, in wax, is approved by

the patient.

After the final prosthesis is

processed into acrylic, it is

tried in and relined with

Impregum impression

material and used to create a

final master cast.

Self curing acrylic is

used to replace the

Impregum

impression material

and create a smooth

and polished intaglio

surface that has been

contoured for clean

ability.

Acrylic wears during function and All-on-

Four prostheses are made of acrylic, so it only

stands to reason that at some point, the

prostheses or at least the denture teeth will

need to be replaced…..

…and some patients

ignore the wear for way

too long.

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Replacing the dentures, or at least, the

posterior teeth, can re-establish the proper

vertical dimension of occlusion.

Poor fitting maxillary

denture.

Excessive denture adhesive

required for retention.

Pain in anterior vestibule and

burning sensation in palate.

Heavy anterior occlusion.

Destruction of anterior maxilla.

Inadequate posterior support.

Poor esthetics and speech.

Heavy anterior contact and function

with inadequate posterior support

produces resorption of the anterior

ridge.

Inadequate coverage of the

retromolar pads increases

anterior contact in function.

Destruction of the anterior ridge

from hyper function is a hallmark of

“Kelly’s Syndrome”.

Anterior teeth are set for lip

support, esthetics and speech

production.

Posterior teeth are set on the

occlusal plane which is defined as a

line drawn from the edges of the

maxillary incisors through a point

midway up the retromolar pad

when mounted in CO.

A mandibular treatment partial

denture or trial prosthesis is

constructed with a posterior bite block

set in lingualized occlusion at a vertical

dimension of occlusion that produces

anterior disocclusion in CO and

function.

The trial prostheses are processed into

acrylic, delivered to the patient lined

with soft tissue conditioning material

and worn for a sufficient length of time

to recondition the tissues and produce

functional impressions.

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Depending on the severity of tissue

damage, it may take a month of tissue

conditioning and care by the patient to

bring the tissues back to a comfortable

state.

The prostheses are finished with porcelain teeth in ligualized posterior

occlusion. The anterior teeth are disoccluded in CO and function.

Patient is in her 70’s and has worn dentures for more than 30 years.

For a number of those years she had some implant retention that

was lost and replaced several times. The patient’s health precludes

more surgery so she has opted for a conventional maxillary denture

with o-ring retention on her lone remaining implant.

The upper treatment denture is lined with Hydrocast

tissue conditioning material to eliminate the effects of

long term use of denture adhesives and to produce the

final functional impression.

An index made of the

position of the teeth of the

treatment denture

demonstrates the gross

loss of alveolar ridge

structure.

17 – 20 mm

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Solid bilateral posterior lingualized

occlusion disoccludes the anterior

teeth in function and keeps the

denture seated on the residual ridge.

To insure long term wear, the lingual

cusps are cast in Type IV hard gold.

Thirty-three year old with advanced periodontal bone loss in anterior and

posterior quadrants. Five maxillary and six mandibular teeth were saved and

restored with a combination of fixed and removable prostheses.

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Patient used the combination prostheses for 26 years before the maxillary

abutment teeth failed, necessitating extraction and replacement with a

complete denture.

Lower partial denture with metal occlusals.

Hydroxyapatite augmentation of

tuberosities placed at original

surgery in 1990.

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Atrophic maxillary ridge is the result of

advanced periodontal problems as a young

adult. Patient desires implant placement to

help retain maxillary denture.

Step One: Create clear duplicate of upper denture.

Identify and mark potential

implant sites.

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Surgical stent with gutta percha points imbedded at potential implant

sites.

Step Three: Scan #1

Gutta Percha Markers

Potential position of implants is not within solid bone. Using the

density determining software, new locations ( ) for the implants were

found 6 and 7 mm distal to position of gutta percha markers.

Zimmer® Dental Tapered Screw-Vent

(3.7mm x 11.5mm)

Zimmer® Dental Tapered

Screw-Vent (3.7mm x 10mm)

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Multi-purpose fixture mount / transfer

coping used as implant driver,

impression post and when cut down and

reshaped: a healing head.

Four months later…………..

Locator abutments

Locator male housings

with retentive nylon

insert.

Approximately 10 years previously, patient had multiple implants placed

in the maxilla for a hybrid prosthesis. The implants failed and the patient

presented with a severely atrophic maxillary ridge.

The two implants in the mandible can be used to support a lower partial

denture that will supply occlusal support for the maxillary denture. The

two zygomatic implants remaining from the original surgery will be

exposed and restored with Locator abutment heads to help retain the

maxillary denture.

Soft-lined treatment denture and partial

denture used during healing phase to

reestablish tooth position, vertical

dimension of occlusion, and function.

Ball overdenture heads are used

during the healing phase to help

retain the prostheses.

Locator abutment heads used for

retention of the maxillary denture.

Angulation of abutment heads requires

use of at least one extended range male.

Maxillary and mandibular treatment prostheses.

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Within 6 months, the patient lost the zygomatic

implant on her left side. Four years later, she lost

the one on her right and now uses denture

adhesive to retain her upper denture.

What happens if the patient loses the

implants and there is not enough

residual bone to support new

implants? The patient has become a

“dental cripple”. Molloplast-B, a

heat-cured, silicone soft liner becomes

the best option.

Fifteen years prior to these

pictures, the patient was a

heavy smoker. Over several

years, he had placed and then

lost eight implants and most of

the residual bone.

Now, as a non-smoker he

wished to be retreated. The

residual bone was sufficient to

support two implants with

Locator abutments.

Two Locator abutments support

and retain a complete lower

denture. The central fossae of the

posterior teeth were cast in hard

gold to reduce wear to the

maxillary ceramic restorations.

Prominent lingual cusps of the

maxillary posterior teeth function in

the open, shallow fossae of the

mandibular posterior teeth in

ligualized occlusion. The metal

occlusals are replaceable to maintain

the ideal vertical dimension of

occlusion.

Patient received radiation

treatment to the anterior maxilla

for a cancerous tumor of the left

nares. Several years later, she

had the maxillary left cuspid

(#11) extracted.

The site did not heal and the

bone of the maxilla developed

osteoradionecrosis.

Surgery resulted in the loss of all

maxillary teeth and a large

portion of the bone of the

anterior maxilla. A fistula that

communicated with the left

sinus remained patent.

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Soft-lined treatment prostheses worn

during the healing period.

Only bone remaining for implant placement

is in the tuberosities.

Retention of the maxillary

denture achieved with o-

ring abutments, bilateral

posterior occlusion and no

anterior contact in centric

occlusion or function.

This case was originally

conceived as a fixed hybrid

with distal cantilever

pontics. The pontics caused

movement in the bar and the

case was redone as a implant

borne complete

denture…removable by the

dentist. The two maxillary

implant were never used.

Prosthesis has been in

function for more than 20

years and the patient has

practiced excellent hygiene

as evidenced by the healthy

condition of the gingiva

around the implant

abutments.

The chief complaint is the

worn condition of the

prostheses.

As with all acrylic prostheses, wear

created by function reduces the

effectiveness and appearance of the

prosthesis.

Loss of vertical dimension of occlusion

Occlusal wear

Incisal wear

Maxillary prosthesis with acrylic teeth

replaced with complete denture made

with anterior and posterior porcelain

teeth. Lower acrylic incisors replaced

with IPN resin teeth.

Worn posterior teeth rebuilt

into occlusion with self curing

acrylic resin and then cast

into metal occlusal surfaces.

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True Class III

60 year of history of wearing complete dentures.

Present set is 30 years old.

Soft-lined treatment dentures with mandibular

bite block occlusion are used to assess speech

and appearance, re-establish a comfortable

vertical dimension of occlusion, recondition the

tissues of the ridges and produce functional

impressions.

Functional impressions in the treatment dentures produce master

casts mounted in a Class III occlusal relationship at an increased

vertical dimension of occlusion. The increased VDO allowed for

better positioning of anterior teeth for appearance and speech.

Porcelain posterior denture teeth

set in lingualized occlusion and a

posterior cross bite.

Molloplast-B Heat

Processed Silicone Soft

Liner

Custom contoured

and tinted acrylic.

CEJ

To accommodate a milled implant bar

and the supporting abutments, 5 to 6

mm of bone must be removed above

the cemento-enamel junction of the

extracted teeth.

Only time will tell if this is a good idea

or not.

So, who is Dr. Smanda?

Our Website: Drs. “M” and “A” . Com = drsmanda.com

Our Mobile Site: Mag(innis) App(leton) App = magappapp.com

Our Phone Number: (225) 201-1000

Our QR Code:

magappapp.com

Technology to stay in touchTechnology to stay in touch and educate your patients:

www.drsmanda.com

Drs. Maginnis and Appleton

PROSTHODONTICS:

Dr. Michael J. Maginnis

Dr. Isaac E. Appleton

GENERAL DENTISTRY:

Dr. Glenn E. Appleton

Dr. Thomas C. Kiebach

On the Web: www.drsmanda.com7742 Office Park Blvd.

Baton Rouge, LA 70809

(225) 201-1000