clinical outcome of 103 consecutive zygomatic implants a 6–48 months follow-up study

Clinical outcome of 103 consecutivezygomatic implants: a 6–48 monthsfollow-up study

Chantal MalevezMarcelo AbarcaFrancoise DurduPhilippe Daelemans

Authors’ affiliation:Chantal Malevez, Marcelo Abarca, FrancoiseDurdu, Philippe Daelemans, Department ofMaxillofacial Surgery and Dentistry, ErasmeHospital, Universite Libre de Bruxelles, BrusselsBelgium

Correspondence to:Dr Chantal MalevezDepartment of Maxillofacial Surgery and DentistryErasme Hospital Universite Libre de Bruxelles808 Route de Lennik 1070 BrusselsBelgiumTel.: +32 2 555 44 74Fax: +32 2 555 45 99e-mail: [email protected]

Key words: zygomatic implants, zygoma bone, atrophic maxilla, oral implants, edentulism

Abstract: The purpose of this study was to evaluate retrospectively, after a period of 6–48

months follow-up of prosthetic loading, the survival rate of 103 zygomatic implants inserted

in 55 totally edentulous severely resorbed upper jaws. Fifty-five consecutive patients, 41

females and 14 males, with severe maxillary bone resorption were rehabilitated by means of

a fixed prosthesis supported by either 1 or 2 zygomatic implants, and 2–6 maxillary implants.

This retrospective study calculated success and survival rates at both the prosthetic and

implant levels. Out of 55 prostheses, 52 were screwed on top of the implants, while 3 were

modified due to the loss of standard additional implants and transformed in semimovable

prosthesis. Although osseointegration in the zygomatic region is difficult to evaluate, no

zygomatic implant was considered fibrously encapsulated and they are all still in function.

This study confirms that the zygoma bone can offer a predictable anchorage and support

function for a fixed prosthesis in severely resorbed maxillae.

Long-term results of fixed prosthesis on 2-

stage c.p. titanium screw-shaped oral im-

plants indicate a predictable treatment

outcome (Adell et al. 1990; van Steen-

berghe et al. 1990).

However, implant insertion and prosthe-

tic rehabilitation of patients with an ex-

tremely atrophied maxilla are especially

difficult issues. Bone resorption in the

posterior region, widening of the sinuses,

and anterior alveolar bone resorption can

dramatically reduce the possibility of im-

plant insertion and prosthetic rehabilita-

tion. Ideally, these patients would have to

be treated with bone augmentation techni-

ques or onlay or veneer bone grafting,

combined with sinus grafts or possibly

nasal floor augmentation (Triplett et al.

2000; Kahnberg et al. 2001).

Localised ridge augmentations by means

of a membrane, the so-called guided bone

regeneration (GBR) technique, is a docu-

mented procedure, but data are limited for

the totally edentulous patient (Buser et al.

1993; Simion et al. 2001).

Autologous bone grafting has given sa-

tisfactory success rates. This well-docu-

mented technique implies heavy surgery,

and sometimes considerable morbidity also

at the donor site (Breine & Branemark

1980; Isaksson 1994; Hurzeler et al. 1996;

Lekholm et al. 1999).

The new zygomatic implantation tech-

nique proposes an alternative to this bone

grafting by using the zygoma as a strong

anchorage. Indications for the placement of

zygomatic implants are:

� Sufficient bone volume in the anterior

region of the maxilla: the length of the

maxillary arch with a minimum height

of 10 mm and width of 4 mm allows the

placement of 2–4 implants, but the

resorption of the posterior maxilla re-

duces the possibility of placement of

standard implants.Copyright r Blackwell Munksgaard 2003

Date:Accepted 20 January 2003

To cite this article:Malevez C, Abarca M, Durdu F, Daelemans P. Clinicaloutcome of 103 consecutive zygomatic implants: a 6–48months follow-up study.Clin. Oral Impl. Res. 15, 2004; 18–22doi: 10.1046/j.1600-0501.2003.00985.x

18

d

Sticky Note

Clinical Oral Implants Research Volume 15, Issue 1, Date: February 2004, Pages: 18-22

� Insufficient bone volume in the anterior

region of the maxilla: this situation

necessitates onlay graft or GBR for

implant placement. Sinus grafting for

the posterior region could be contra-

indicated for clinical reasons or avoided

by the use of the zygomatic implants.

The aim of this retrospective study in

consecutive patients was to evaluate the

clinical outcome of the zygomatic implants

and the prostheses they carry.

Material and methodsPatients

The study was based on 55 patients treated

at the Department of Maxillofacial Surgery

and Dentistry of the Erasme Hospital

(Universite Libre de Bruxelles), between

December 1997 and November 2001.

All 55 patients were provided with

Branemark Systems Zygomaticus fixtures

(Nobel Biocare AB, Goteborg, Sweden), 41

women and 14 men. The average age for

the men was 62 (range 40–76) years and for

the women 57 (range 22–79) years.

All patients were totally edentulous in

the upper jaw: 21 patients were full

edentulous, while 34 patients were par-

tially edentulous. Thirty-seven patients

were nonsmokers, 11 patients smoked

more than 10 cigarettes a day, and 7

patients reported that they smoked occa-

sionally, but less than 10 cigarettes a day.

The medical history of the patients is

shown in Table 1.

The selection criteria for the zygomatic

implantation were: no possibility to insert

5–6 standard implants in the anterior region

of the maxilla, a posterior bone height of

less than 5 mm. If the anterior maxillary

height was less than 13 mm and the width

less than 4 mm, an additional bone grafting

was performed in the anterior region.

Exclusion criteria were acute infections

of the sinuses.

Implants

Zygomatic implants are available in 8

different lengths ranging from 30 to 52.5

mm. The portion that engages the residual

maxillary alveolar process has a diameter of

4.5 mm, while the apical portion inserted

in the zygoma has a diameter of 4.0 mm

(Fig. 1).

The distribution lengths of implants are

shown in Table 2.

A total of 103 zygomatic implants were

placed, generally 2, in each patient. Indeed

in 7 patients unilateral anatomical reasons

prevented the placement of 2 implants.

Bone density and bone quantity were

evaluated by eye inspection on the basis

of orthopantomographs and CT scans.

A number of 194 standard Branemark

Systems implants (Nobel Biocare AB,

Goteborg, Sweden) were placed in the

anterior maxilla following the protocol

defined by Branemark (Branemark et al.

1985). Patients had a combination of 1 or 2

zygoma implants with 2, 3, 4, 5 or 6

Branemark Systems implants of type

Regular Platform diameter 3.75 mm (54

patients) and Wide Platform diameter 5.0

mm (1 patient) in the anterior maxilla. In

patients where 6 implants were placed, 2

were inserted in the maxillary tuberosity.

The distribution of zygomatic and anterior

implants is shown in Table 3.

Surgical procedures

All the zygomatic implants were placed

under general anesthesia. A Le Fort I

osteotomy incision was used in 2 patients.

For the others, this incision was modified

for technical reasons to a palatal incision,

which exposes the entire maxillary alveolar

process from zygomatic buttress to zygo-

matic butress. The drilled hole ends at the

junction of the zygomatic arch and the

lateral orbital rim. The zygomatic implant

ultimately engages the bone in both the

zygoma and the maxillary alveolus

(Branemark 1998).

Antibiotic prophylaxis, mostly amoxicil-

lin 2 g/day for 5 days, was used in all

patients. Except for the first 2 patients, all

received corticoids to avoid the important

swelling of the lips and face.

Normally, the placement of additional

standard implants in the anterior sector of

the maxilla is done at the time of the

placement of the zygomatic implants, but

in 7 patients, due to the extreme bone

resorption they presented, an autologous

onlay or veneer bone graft was placed at the

time of the first surgery (Fig. 2). The

placement of the standard implants was

then delayed to a second surgery a few

months later (4–6 months).

All anterior implants were placed routi-

nely according to a 2-stage procedure.

Table 1. Summary of patients’ medical his-tories

Medical history Study group

Diabetes (type 2) 1Hypertension 6Allergy 5Antidepressive drugs 1Parkinson 1Hepatitis 2

Fig. 1. The zygomatic implant and its different measures.

Table 2. Distribution of the different zygo-ma implants according to their length

Lengthofzygomaticimplants in mm

Number of zygomaimplants placed

30 035 640 4342.5 345 4247.5 050 952.5 0

Total of fixtures 103

Table 3. Relation between number of im-plants in the anterior sector of the maxillaand the number of zygomatic implants inthe posterior sector in the group ofpatients

Number of implantsin the anterior sectorof the maxilla

2 3 4 5 6

1 zygoma implant 0 0 1 2 32 zygoma implants 15 7 24 3 0

Total of patients 15 7 25 5 3

Malevez et al . Clinical outcome of 103 consecutive zygomatic implants

19 | Clin. Oral Impl. Res. 15, 2004 / 18–22

Prosthetic procedures

On the day of the abutment connection,

standard abutments were installed on all

implants and all the implants were immedi-

ately connected by a rigid bar or a provisional

acrylic prosthesis screwed on top of them.

The final prosthetic procedure started

about 10 days after abutment connection

according to the standard prosthetic proto-

col (Branemark et al. 1985).

The final prosthesis consisted of a con-

ventional gold framework with acrylic

teeth. In 2 patients, the teeth were made

of porcelain (Figs. 3, 4)

Results

None of the 103 zygomatic implants failed.

A life table of zygomatic implants is shown

in Table 4.

Out of all the 194 placed in the anterior

maxilla, 16 were lost, which means the

success rate was 91.75%.

These losses clustered in 7 patients but

all, except 3, still wear a fixed prosthesis.

These 3 patients went back to a removable

prosthesis, of whom 1, who lost all the

standard implants (3), got 2 magnets on the

zygomatic implants.

One complication was observed prior to the

placement of the prosthesis, 1 patient pre-

sented a severe infection of the sinus, which

was successfully treated with antibiotics.

After prosthesis placement, patients

were controlled after 1 week, 1 month, 3

months, 6, 12, 24, 36 up to 42 months.

Stability of the zygomatic implants, con-

trol of plaque and inflammation, bleeding on

probing were performed at all the implants

sites and for the anterior standard implant

retroalveolar radiographies were also realised

at 3 and 6 months and once a year.

Orthopantomograms were realised on all

the patients after surgery at the time of the

insertion of the prosthesis, but this exam-

ination could not give relevant information.

In 3 patients, facial X-rays gave a better

information concerning the localisation of

the zygomatic implant.

In cases where bone grafting was per-

formed, CTscans were realised but could not

contribute to any conclusions concerning

osseointegration of the zygomatic implants.

After prosthesis placement, 5 patients

had sinusitis that, however, could not be

associated with the zygoma implants. One

patient had a variety of several complaints

due to psychological problems, 1 patient

had problems with oral hygiene control,

and 1 patient had aesthetic problems.

Discussion

Few reports have been published about

zygomatic implants (Higuchi 2000;

Schramm et al. 2000; Stevenson & Austin

2000; Bedrossian & Stumpel 2001; Parel et

al. 2001; Uchida et al. 2001). None offers a

follow-up as long as the present study. The

use of zygomatic implants represents an

interesting alternative in the rehabilitation

of the fully edentulous patient. It offers a

solid and an extended anchorage in a region

situated at an important distance from the

occlusal level. Indeed, histological analysis

of the zygoma shows regular trabeculae and

compact bone with an osseous density of

98% (Gosain et al. 1998).

Fig. 3. Final bridge made of gold and porcelain screwed on the 2 zygomatic implants and 4 standard ones.

Fig. 2. Installation of the left zygomatic implant. The top of the implant is seen on the top of the zygoma.



The zygoma bone can be compared to a

pyramid, offering an interesting anatomy

for the insertion of implants (Karlan &

Cassisi 1979). The proven strength of

this anchorage contrasts with the poor

bone quality (mostly type IV) of the poster-

ior maxilla.

Owing to this bone density, it has also

been used in the treatment of the max-

illofacial fractures, for the insertion of

miniplates (Champy et al. 1986). It has

also been used as well during orthodontic

treatment, offering a fixed anchorage to

allow tooth movements (Melsen et al.

1998). In the protraction of the maxilla,

one animal study uses the zygoma bone as

an anchorage place (Smalley et al. 1988). In

maxillofacial prosthesis, the zygoma bone

was utilized as an anchorage for the

placement of implants for a facial pros-

thesis (Sabin et al. 1995). Finally after

maxillectomy, zygomatic implants were

connected with other standard implants

in a conventional screwed prosthesis (Izzo

et al. 1994).

For all these reasons, zygoma bone

should be considered as a steady anchorage

for rehabilitation of the very resorbed

maxilla.

In the present study, only survival was

reported since the application of success

criteria is technically impossible.

Only clinical appreciation about the

stability of the implants was performed:

no pain, no swelling, no infection, and no

mobility.

A relevant radiographic analysis of bone

apposition is also impossible around the

implant in the zygoma.

All zygomatic implants in this series are

still in function, without complications,

and with no signs of pain, infection or any

pathology.

Conclusions

The zygomatic implants have been devel-

oped for compromised maxillary situations.

The zygomatic implant offers a predictable

therapeutic solution as has been shown in

this up-to-4-year observation on more than

100 consecutive implants without a single

implant loss.

There is a need to develop clinical and/or

radiological criteria to assess whether zy-

goma implants have achieved an intimate

bone-to-implant contact.

Resume

Le but de cette etude a ete d’evaluer retrospective-

ment, apres une periode de six a 48 mois apres la

mise en charge prothetique, le taux de survie de 103

implants zygomatiques inseres chez 55 edentes

complets avec machoires superieures extremement

resorbees. Cinquante-cinq patients (41 femmes et

quatorze hommes) avec une resorption osseuse

maxillaire tres severe ont ete soignes a l’aide d’une

prothese fixee supportee par un ou deux implants

zygomatique et deux a six implants maxillaires.

Cette etude retrospective a calcule le taux de survie

et le taux de succes tant au niveau prothetique et

qu’implantaire. Des 55 protheses, 52 ont ete vissees

sur les implants tandis que trois ont ete modifiees vu

la perte d’implants standards supplementaires et

transformees en protheses semi-amovibles. Bien que

l’osteoıntegration dans la region zygomatique soit

difficile a evaluer, aucun implant zygomatique n’a

ete considere comme encapsule fibreusement et ils

sont encore tous en fonction. Cette etude confirme

que l’os zygomatique peut offrir un ancrage pre-

visible et unun support de support pour une

prothese fixee dans les cas de maxillaires fortement

resorbes.

Zusammenfassung

Die klinischen Ergebnisse von 103 Implantaten im

Jochbein. Eine Langzeitstudie uber 6–48 Monate.

Das Ziel dieser Studie war es, bei 55 vollstandig

zahnlosen und massiv resorbierten Oberkiefern die

Fig. 4. Facial X-ray showing a global image of the rehabilitation on 2 zygomatic implants and 2 standard ones.

Table 4. Life-table analysis showing survival rates and cumulative survival rates (CSR) ofzygomatic implants

Period of time Number ofzygomatic implants

placed

Failed Survivalrate %

CSR %

Placement–Prosthesis insertion 103 0 100 100Prosthesis insertion–6 months 103 0 100 1006–12 months 101 0 100 10012–24 months 64 0 100 10024–36 months 34 0 100 10036–48 months 10 0 100 10048 months 2 0 100 100



Uberlebensrate von 103 Implantaten im Jochbein

retrospektiv zu untersuchen. Die Beobachtungszeit

betrug 6–48 Monate nach prothetischer Versorgung.

55 Patienten, 41 Frauen und 14 Manner, die eine

ausgedehnte Knochenresorption des Oberkiefers

zeigten, wurden mit einer festsitzenden Brucke

versorgt, die von 1–2 Implantaten im Jochbein und

2–6 weiteren Oberkieferimplantaten getragen wurde.

Diese retrospektive Studie errechnete Erfolgsrate

und Uberlebensrate sowohl der prothetischen Re-

konstruktion, wie auch der Implantate. Von den 55

Brucken waren 52 auf den Implantaten verschraubt,

und 3 infolge Verlust von Standardimplantaten zu

bedingt abnehmbaren Brucken umgebaut.

Obwohl die Osseointegration in der Region des

Jochbeins schwierig zu beurteilen ist, musste keines

dieser Implantate als bindegewebig eingeheilt be-

zeichnet werden und alle sind immer noch in

Funktion.

Diese Arbeit belegt, dass der Knochen des Jochbeins

ein voraussagbare Verankerung und Haltefunktion

fur eine festsitzende Brucke bei massiv resorbierten

Oberkiefern liefern kann.

Resumen

La intencion de este estudio fue evaluar retro-

spectivamente, tras un periodo de 6–48 meses de

seguimiento de carga prostetica, el ındice se super-

vivencia de 103 implantes zigomaticos insertados en

55 maxilares superiores edentulos severamente

reabsorbidos.

Se rehabilitaron 55 pacientes consecutivos, 41

mujeres y 14 hombres, con reabsorcion osea severa

del maxilar, por medio de una protesis fija soportada

por 1 o 2 implantes zigomaticos, y de 2 a 6 implantes

maxilares.

Este estudio retrospectivo calculo los ındices de exito

y supervivencia tanto a nivel de la protesis como del

implante. De las 55 protesis, 52 se atornillaron sobre

los implantes mientras que 3 se modificaron debido a

la perdida de implantes estandar adicionales y se

transformaron en protesis semimoviles.

Aunque la osteointegracion en la region zigomatica

es difıcil de evaluar, no se considero a ningun

implante zigomatico como fibrosamente encapsula-

do y estan aun en funcion.

Este estudio confirma que el hueso zigomatico pude

ofrecer un anclaje predecible y funcion de soporte para

una protesis fija en el maxilar severamente reabsorbido.

References

Adell, R., Eriksson, B., Lekholm, U. & Branemark,

P.-I. (1990) Long term follow-up study of osseoin-

tegrated implants in the treatment of totally

edentulous jaws. International Journal of Oral &

Maxillofacial Implants 5: 347–359.

Bedrossian, E. & Stumpel, L. (2001) Immediate

stabilization at stage II of zygomatic implants:

rationale and technique. Journal of Prosthetic

Dentistry 86: 10–14.

Branemark, P.-I. (1998) Surgery and fixture installa-

tion. Zygomaticus Fixture Clinical Procedures, 1st

edn. Goteborg, Sweden: NobelBiocare AB.

Branemark, P.-I., Zarb, G.A. & Albrektsson, T.

(1985) Tissue-integrated Prosthesis, 211–282.

Chicago: Quintessence Publishing Co.

Breine, U. & Branemark, P.I. (1980) Reconstruction

of alveolar jaw bone. An experimental and clinical

study of inmediate and performed autologous bone

grafts in combination with osseointegrated im-

plants. Scandinavian Journal of Plastic and

Reconstructive Surgery and Hand Surgery 14:

23–48.

Buser, D., Dula, K., Belser, U., Hirt, H.P. & Berthold,

H. (1993) Localized ridge augmentation using

guided bone regeneration. 1. Surgical procedure in

the maxilla. International Journal of Periodontics

and Restorative Dentistry 13: 29–45.

Champy, M., Lodde, J.P., Kahn, J.L. & Kielwasser,

P. (1986) Attempt at systematization in the

treatment of isolated fractures of the zygomatic

bone: techniques and results. Journal of Otolar-

yngology 15: 39–43.

Gosain, A.K., Song, L., Capel, C.C., Corrao, M.A. &

Lim, T.H. (1998) Biomechanical and histologic

alteration of facial recipient bone after reconstruc-

tion with autogenous bone grafts and alloplastic

implants: a 1-year study. Plastic and Reconstruc-

tive Surgery 101: 1561–1571.

Higuchi, K. (2000) The zygomaticus fixture: an

alternative approach for implant anchorage in the

posterior maxilla. Annals of the Royal Australa-

sian College of Dental Surgeons 15: 28–33.

Hurzeler, M.K., Kirsch, A., Ackermann, K.-L. &

Quinones, C.R. (1996) Reconstruction of the

severely resorbed maxilla with dental implants in

the augmented maxillary sinus: a 5-year clinical

investigation. International Journal of Oral &


Isaksson, S. (1994) Evaluation of three bone grafting

techniques for severely resorbed maxillae in

conjuction with immediate endosseous implants.

International Journal of Oral & Maxillofacial

Implants 9: 679–688.

Izzo, S.R., Berger, J.R., Joseph, A.C. & lazow, S.K.

(1994) Reconstruction after total maxillectomy

using an implant-retained prosthesis: a case report.

International Journal of Oral & Maxillofacial

Implants 9: 593–595.

Kahnberg, K.-E., Ekestubbe, A., Grondahl, K.,

Nilsson, P. & Hirsch, J.-M. (2001) Sinus lifting

procedure. I. One-stage surgery with bone trans-

plant and implants. Clinical Oral Implants

Research 12: 479–487.

Karlan, M.S. & Cassisi, N.J. (1979) Fractures of the

zygoma. A geometric, biomechanical, and surgical

analysis. Archives of Otolaryngology 105: 320–327.

Lekholm, U., Wannfors, S., Isaksson, B. & Adiels-

son, B. (1999) Oral implants in combination with

bone grafts. A 3-year retrospective multicenter

study using the Branemark implant system.

International Journal of Oral and Maxillofacial

Surgery 28: 181–187.

Melsen, B., Petersen, J.K. & Costa, A. (1998)

Zygoma ligatures: an alternative form of maxillary

anchorage. Journal of Clinical Orthodontics 32:

154–158.

Parel, S., Branemark, P.-I., Ohrnell, L.-O. &

Svensson, B. (2001) Remote implant anchorage

for the rehabilitation of maxillary defects. Journal

of Prosthetic Dentistry 86: 377–381.

Sabin, P., Labbe, D., Ferrand, J., Daburon, P. &

Compere, J.F. (1995) Protheses maxillo-faciales

fixees sur implants endo-osseux. A propos de 15

cas. Annales de Chirurgie Plastique et Esthetique

40: 363–370.

Schramm, A., Gellrich, N., Schimming, R. &

Schmelzeisen, R. (2000) Computer-assisted inser-

tion of zygomatic implants (Branemark system)

after extensive tumor surgery. Mund-, Kiefer- und

Gesichtschirurgie 4: 292–295.

Simion, M., Jovanovic, S.A., Tinti, C. &

Benfenati, S.P. (2001) Long-term evaluation of

osseointegrated implants inserted at the time

or after vertical ridge augmentation. A retrospec-

tive study on 123 implants with 1–5 year follow-

up. Clinical Oral Implants Research 12: 35–45.

Smalley, W.M., Shapiro, P.A., Hohl, T.H., Kokich,

V.G. & Branemark, P.I. (1988) Osseointegrated

titanium implants for maxillofacial protraction in

monkeys. American Journal of Orthodontics and

Dentofacial Orthopedics 94: 285–295.

Stevenson, A. & Austin, B. (2000) Zygomatic fixtures –

the Sydney experience. Annals of the Royal Aus-

tralasian College of Dental Surgeons 15: 337–339.

Triplett, R.G., Schow, S.R. & Laskin, D.M.

(2000) Oral and maxillofacial surgery advances in

implant dentistry. International Journal of Oral &


Uchida, Y., Masaaki, G., Takeshi, K. & Toshio, A.

(2001) Measurement of the maxilla and zygoma as

an aid in installing zygomatic implants. Journal of

Oral and Maxillofacial Surgery 59: 1193–1198.

van Steenberghe, D., Lekholm, U., Bolender, C.,

Folmer, T., Henry, P., Herrmann, I., Higuchi, K.,

Laney, W., Linden, U. & Astrand, P. (1990) The

applicability of osseointegrated oral implants in

the rehabilitation of partial edentulism: a prospec-

tive multicenter study on 558 fixtures. Interna-

tional Journal of Oral & Maxillofacial Implants

5: 272–282.



clinical outcome of 103 consecutive zygomatic implants a 6–48 months follow-up study

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