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Rev Clin Periodoncia Implantol Rehabil Oral. 2016;xxx(xx):xxx---xxx

www.elsevier.es/piro

Revista Clínica de Periodoncia,Implantología y Rehabilitación Oral

REVIEW ARTICLE

Zygomatic implant: Late complications in a period of12 years of experience

Hugo N. Filhoa, Wilson S. Amaralb, Claudia Currab, Pâmela L. dos Santosc,∗,Camila L. Cardosoc

a DDS, MSc, PhD, Chairman, Department of Oral and Maxillofacial Surgery, University of Sagrado Coracão, Bauru, São Paulo, Brazilb DDS, MSc-Student, Department of Oral and Maxillofacial Surgery, University of Sagrado Coracão, Bauru, São Paulo, Brazilc DDS, MSc, PhD, Assistant Professor, Department of Oral and Maxillofacial Surgery, University of Sagrado Coracão, Bauru, SãoPaulo, Brazil

Received 28 October 2015; accepted 3 March 2016

KEYWORDSZygomatic implant;Zygomatic fixation;Complications

AbstractPurpose: Zygomatic implants (ZI) constitute a suitable alternative for treating severe maxillaryatrophy. However, a large number of complications associated with ZI have been reported inthe literature. This paper presents the late complications associated with ZI during 12 years ofexperience in the same institution.Materials and methods: All cases of ZI from 2000 to 2013 were retrospectively evaluated andthe major complications relating to this type of rehabilitation were selected to report.Results: The major complications found were: loss of implant, loss of osseointegration, bucco-sinusal communication, fenestration of alveolar mucosa, sinus pathology, and emergency palatefixations.Conclusion: The clinical experience of the dental surgeon is critical in the success of zygomaticfixation. Furthermore, there should be careful planning of rehabilitation to reduce the rate ofcomplications.© 2016 Sociedad de Periodoncia de Chile, Sociedad de Implantología Oral de Chile y Sociedadde Prótesis y Rehabilitación Oral de Chile. Published by Elsevier España, S.L.U. This is anopen access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).

PALABRAS CLAVE Implante zigomático: Las complicaciones tardías en periodo de 12 anos de

Implante cigomático;Fijación cigomatica;Complicación

experiencia

Resumen

Please cite this article in press as: Filho HN, et al. Zygomatic implant: Late complications in a period of 12 years ofexperience. Rev Clin Periodoncia Implantol Rehabil Oral. 2016. http://dx.doi.org/10.1016/j.piro.2016.03.007

Propósito: Los implantes cigomáticos (ZI) constituyen una alternativa adecuada para eltratamiento de la atrofia maxilar severa. Sin embargo, se han observado, en la literatura,

∗ Corresponding author.E-mail address: pamelalsantos@hotmail.com (P.L. dos Santos).

http://dx.doi.org/10.1016/j.piro.2016.03.0070718-5391/© 2016 Sociedad de Periodoncia de Chile, Sociedad de Implantología Oral de Chile y Sociedad de Prótesis y Reha-bilitación Oral de Chile. Published by Elsevier España, S.L.U. This is an open access article under the CC BY-NC-ND license(http://creativecommons.org/licenses/by-nc-nd/4.0/).

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2 H.N. Filho et al.

un gran número de complicaciones asociadas con la ZI. Este trabajo presenta complicacionestardías asociadas con ZI, durante 12 anos de experiencia, en la misma institución.Materiales y Métodos: Todos los casos de ZI, de 2000 a 2013, fueron retrospectivamente eval-uados y las principales complicaciones relacionadas con este tipo de rehabilitación fueronseleccionados para el informe.Resultados: Las mayores complicaciones encontradas fueron: pérdida de implante, la pérdidade osteointegración, comunicación bucosinusal, fenestración de la mucosa alveolar, patologíasinusal y palatina de emergencia de las fijaciones.Conclusiones: La experiencia clínica del cirujano es crítico en el éxito de la fijación cigomático.Además, la planificación de la rehabilitación debe hacerse con cuidado para reducir la tasa decomplicaciones.© 2016 Sociedad de Periodoncia de Chile, Sociedad de Implantología Oral de Chile y Sociedadde Prótesis y Rehabilitación Oral de Chile. Publicado por Elsevier España, S.L.U. Este es unartículo Open Access bajo la licencia CC BY-NC-ND (http://creativecommons.org/licenses/by-nc-nd/4.0/).

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ince the first description, in 1998,1 the rehabilitation usinghe zygomatic implants (ZI) suffered technical modifica-ions over the years, however the indications remained theame: repair the functional aspect of mutilated patientsr in cases of severely resorbed maxillae, which makesifficult to install the conventional fixation.2---4 The greatdvantage of this type of rehabilitation is not only toinimize postoperative morbidity caused by reconstruc-

ive surgeries, but also to eliminate hospitalization, highost and risk of complications. Over the years, it was pro-osed a modification of technique using just four ZI, mainlyhen the pre-maxilla presents severely resorbed.3---5 Then,ith increasing indication, it also increases the complication

ate.Generally, the complications from zygomatic fixation

ay be divided in immediate and late. The immediateomplications are related to post-operative and it is asso-iated with the surgeon experience, the technique applied,he anatomical condition and the individual aspects. Exam-les of immediate complications are: periorbital andonjunctival hematoma, nosebleed, paresthesia and burnsn the skin or labial mucosa. Those complications have aood prognosis. On the other hand, the late complicationsequire a carefully therapy, considering the anatomical site.ome examples of late complication are: loss of fixationr osseointegration, bucco sinusal communication, fenes-ration of the buccal mucosa, chronic sinusitis and sinusathologies, palatal emergency of fixations, mucositis anderi-implantitis.6---14

Recent systematic review studies reported the sur-ival and presence of complications related of zygomaticxation.15 They conclude that the studies with a high level ofvidence are scarce.15 Here in, we report late complicationselated to rehabilitation of the atrophic maxilla, using zygo-atic fixations, during 12 years of experience.

aterial and methods

Please cite this article in press as: Filho HN, et al. Zygomatiexperience. Rev Clin Periodoncia Implantol Rehabil Oral. 2016.

t was performed a retrospectively study in all cases of ZIehabilitation (from 2000 to 2013), in the same institutionUniversity Sagrado Coracão, Bauru, São Paulo, Brazil). It

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as selected only the major complications which occurredn this period.

All cases evaluated were previously selected, discussednd prepared surgically by the team. Imaging examinationnd guides were used to the surgical planning. The post-perative follow up was minutely conducted over the years.

esults

ate complications

oss of fixationoss of the zygomatic fixation may occur as observed inonventional implants. The zygomatic fixation presents fewreas of bone contact along the entire fixation, restrictingo some millimeters in the alveolar region and zygomaticone implantation site. Therefore, it should be found theaximum bone contact between the implant and the zygo-atic process of the maxilla. The adoption of techniques

f externalization and use of maxillary zygomatic pro-ess may provide greater contact area. However, both thelassical technique and the externalization may presentdvantages and disadvantages. The classical technique pro-ects more the fixation, reduces the bone contact area andredisposes occurrence of maxillary sinus complications.he exteriorization presents greater technical facility andreater anchorage, therefore it may result an importanteriimplant involvement, buccal recessions and difficultontrol of oral hygiene. In addition, the extensive boneestruction followed the loss of fixation should be consid-red (Figs. 1 and 2). It is important to consider that theoss of osseointegration in alveolar portion (in the conven-ional technique) does not mean loss of implant, excepthen it is associated in a rotational movement and painful

ymptoms. However, when a buccosinusal communication isstablished, the implant must be removed, even if it wassseointegrated in the zygomatic bone.

oss of osseointegration with or without buccosinusalommunication

c implant: Late complications in a period of 12 years of http://dx.doi.org/10.1016/j.piro.2016.03.007

n the loss of osseointegration, is really important thenvestigation of the presence of fistulas. It is important toonsider the symptomatology to evaluate the success of the

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Zygomatic implant 3

Figure 1 Alveolar fenestration and loss of zygomaticfixation.

Figure 3 Fenestration resulting from external access.

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Figure 2 Bone loss due to the screw hole prosthetic.

implant, even though it is osseointegrated. If the implanthas limited mobility, but ausence of pain and sinusitis, itis possible keep it in function in mutilated patients. If thecase evolves unsatisfactorily, the buccosinusal communi-cation (BSC) is maintained through a fistula. In this case,the implant must be removed, because it can be a wayto contamination. Moving an implant can involve force andalso an osteotomy of zygomatic bone resulting in boneloss of alveolar region. It is essential to reestablish theintegrity of maxillary sinus, using grafts and techniquesof flap rotation to enable the resolution of BSC. Later, areconstructive procedure may be indicated to try anotherzygomatic anchorage.

Fenestration of alveolar mucosaBecause of the cases with severe alveolar resorption, includ-ing in the maxillary zygomatic pillar, the fenestration ofthe alveolar mucosa may occur, creating a retraction ofthe mucosa and exposure thread of the implant (Fig. 3).If it is possible, the fixation must be maintained inside themaxillary sinus, preserving the zygomatic process, an impor-tant anatomic repair to the treatment of complicationsand loss of zygomatic implants. This detail is more impor-tant when the patient presents a ridge with a little lossin height, because the muscle insertion of deep sulcus isfarthest, resulting in gingival retractions. In cases of maxil-

Please cite this article in press as: Filho HN, et al. Zygomatiexperience. Rev Clin Periodoncia Implantol Rehabil Oral. 2016.

lary atrophy, where the muscle insertion is maintained closeof the ridge, the fenestrations are protected, as in muti-lated patients without alveolar portion and the implant isplaced with great fenestration. The treatment of this late

tiat

Figure 4 Sinus pathology resulting from zygomatic implant.

omplication is impracticable and the biggest difficulty is toontrol the bacterial plaque, which is more difficult than inonventional situations. It is noteworthy the importance ofertifying the absence of BSC and periodic follow-up shoulde done to evaluate the periimplant condition.

inus pathologyhe presence of sinus pathology should be detected early,ince the medical history, to avoid late complicationsssociated with the implants. Chronical sinusitis, aller-ic episodes or other sinus pathologies deserve previewultidisciplinary approach with otorhinolaryngologist. Sinus

pproach, through of a bone window with rupture or removalinusal membrane is controversial. The access and removalf sinusal membrane, allowing view and irrigation during thensertion of the implant are justified. Besides, they offerccess to sinusal pathologies like polyps or cysts eventuallynd inside the maxillary sinus (Fig. 4).

alatal emergency of fixationsttempts of changing protocol, through the buccalpproaches, change in implant design, change of incline ofmplant head or use new intermediates, aim to optimize

c implant: Late complications in a period of 12 years of http://dx.doi.org/10.1016/j.piro.2016.03.007

he rehabilitation, both phonetically as in the biomechan-cs of the system.1---3 Maxillae with large buccal concavitynd transversal atresia restrict the results obtained in thisechniques. In favorable situations, with enough bone, these

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Figure 5 Positioning of palatal implants generating a leverarm on the prosthesis.

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Figure 6 Access palatal of zygomatic implant.

echnical changes offer little benefit compared to the orig-nal protocol, because both are performed in situations ofood prognosis. In cases of facial deformities and big atre-ias, the buccal approaches are interesting, since it does notxist the possibility of alveolar anchoring.4 This are border-ine cases, where there is not the best option to treatment,ven considering the risks. In the conventional cases, thelveolar anchoring is very important and must be consideredFigs. 5 and 6).

ucositis and periimplantitishe condition of normality of periimplant tissue of reha-ilitation implant-supported, depends of some factors like:eature of mucosa, type of prosthetic connection, form ofonvenience of the prosthesis and, specially, the capacityf control of bacterial plaque by the patient. Periim-lant changes can appear in any implant, but in zygomaticmplants, there are some important differences, which muste considered. Regarding the kind of mucosa, two aspectsre important: the volume of mucosa (since gingival marginntil the alveolar crest) and its nature. The ideal conditions the positioning of intermediate in keratinized mucosa andhe palatal emergency contributes in this case. It is impor-ant to estimate the availability of masticatory mucosa.ound its shortage, the access must include an incision morealatal, that allows a repositioning more buccal of suture

Please cite this article in press as: Filho HN, et al. Zygomatiexperience. Rev Clin Periodoncia Implantol Rehabil Oral. 2016.

nd, consequently, improve the periimplant tissue condi-ions. When the head of the implant is positioned palatally,r there is a big volume of keratinized mucosa, the incisionhould be applied in buccal. As mentioned, a buccal access,

apli

Figure 7 Mucositis caused by zygomatic implant.

ext to the transition of alveolar mucosa can allow thechievement of some fenestration, from where the inter-ediates appeared, far of the incision line. The advantage

f this technique includes stability of the retail and absencef risk of dehiscence around of the intermediate, providing aetter repair, greater predictability the height of the inter-ediate selected and greater facility of removal of suture

n procedures of immediate loading.However, not only the quality of the mucosa around

he implant is important, but also its thickness. When theucosa is very thick, this implies in deep gingival sulcus, longpithelium and wide area of adaptation conjunctiva. Thisondition in occurrence of bacterial plaque, promotes theormation of inflammatory process and mucositis (Fig. 7).he biological distance corresponds the space in millime-ers since the bone crest until the gingival margin, thatn case of implant can change from 2 to 3 mm. Thus, thereater the thickness of the mucosa, more chance to occureriimplantar alterations. In palate region, the thickness isifferent compared to the alveolar crest, related the biguantity of connective tissue, adipose tissue and presence ofmall salivary glands. Although, must be reduced internally,ith scalpel blades help, to limit the thickness to 2---3 mm.

n this way, the size of intermediates will decline, allowinghe exposure of the head of the zygomatic implant. Oncet is angled, the zygomatic implant presents 3---4 mm abovehe bone level, what would put the connection area with thentermediate above the gingival margin, do not affecting thearginal bone loss.The incidence of mucositis is considered high.16 The dif-

culty to control mucositis can result in an evolution ofhe disease with bone destruction, featuring periimplanti-is, which is a high level when related to zygomatic implant,nce the volume alveolar bone is limited. The loss of 2---3 mmay result in loss of total bone volume favoring a buccos-

nusal communication. In addition, bone loss is not relatednly to the effect of the connection area, but also in biome-hanical conditions of plaque control by the patient. Thus,hanges in the head of fixation, that eliminate the holef transfixation of prosthetic screw; the decreasing of thehickness of the mucosa; the manufacturing of prosthesesith convenience form that make it difficult to grip fillingsnd make easier the mechanical control of the plaque by the

c implant: Late complications in a period of 12 years of http://dx.doi.org/10.1016/j.piro.2016.03.007

atient, these are the essential requirements to the systemongevity based in maxillary rehabilitation using zygomaticmplant.

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Zygomatic implant

Discussion

Although studies have demonstrated that zygomatic implantis a viable and successful option for rehabilitation of patientswith severe maxillary atrophy, the complications of thistreatment are being discussed in the recent literature.15

Recent systematic review, evaluated the level of survivaland presence of complications in a period of 12 years.Only 42 studies or clinical cases of zygomatic implant wereincluded in the criteria selection. The cumulative levelof survival was about 96.7%, however, the complicationsrelated in this studies were: 70 cases of sinusitis, 48 casesof infection of soft tissues, 15 cases of paresthesia and 17cases of fistula buccosinusal. It is important to note that themost of the studies evaluated did not show if had or not anycomplication. Finally, the authors conclude the necessity ofmore studies with a long period of follow up.15

In relation to the access, the opening of anterior wall, aspracticed by the Caldwell Luc technique, contribute to morerisk of complication postoperative as sensorial alterations,penetration of soft tissue inside of the sinus, creating sinus-itis and other pathologies like surgical cysts.17,18 However,authors showed the absence of the relation of the openingof anterior wall, in this surgery, with complications.19 Morethan that, showed through of sinuscopia the perfect har-mony of the implant inside of maxillary sinus with normalmucosa around the fixations.

To the safety that the practical of the opening of anteriorwall offers to the operator, allowing a good control of thedirecting of the milling and installation of the fixation seemsa very indicated attitude, especially to surgeons with lessexperience. If it is possible, the sinusal membrane must bepreserved.

It is important to highlight that what is understood byzygomatic fixation with a long period of control, comes fromthe operated cases with a classical technique, using theosteotomy of the anterior wall, without any care with themembrane and with no reposition of the buccal bone plateas suggested here.20---23,10 Thus, technique and proceduresmentioned here represent tendencies to optimize the goodresults obtained with this dedicated system.

For some authors, the palatal emergency of the fixa-tions is the biggest problem of this technique for providinga palatal positioning of the head of the implant. There is astudy that this emergency could induce phonetic changesand specially some local discomfort to the patient. Thisworry appears in attempts to change the protocol, withbuccal approaches1,2 change in the draw of the implant,3

with modification of the bending of its head or even newintermediates.24 Though, the reasons above cannot justifythis tests, once that a reduced number of patients presentsthis complaint. Perhaps, the main reasons to get an opti-mization of the positioning of the zygomatic fixation, arerelated to biomechanics of the prostheses in an attempt ofreduce the side offsets, and so gets more control of hygieneby the patient. Thus, is important the efforts in this way,but the bone anatomy keep being the biggest problem tothe ideal location of the implant.19,25

Please cite this article in press as: Filho HN, et al. Zygomatiexperience. Rev Clin Periodoncia Implantol Rehabil Oral. 2016.

There are still some complications in this technique. Thehard access, as the instruments used make lacerations inthe lips and a bad post-operative. It is important to remem-ber that as all implants, they must be installed in a good

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ositioning for the biomechanical system. The small area ofnchoring that is allowed in the zygomatic bone is also aechnical disabilities, because this stays anchored just in anpical portion, what provides a lever that committed theong life of rehabilitations.

Here in, the same complications found in the literatureere discussed. The immediate complications usually aressociated by the technique. The late complications likeinusitis, inflammation of periimplant soft tissue and pares-hesia are commonly found in the literature. The zygomaticxation not only depends of the surgeon’s experience butlso has limitations. The limitations and indications shoulde understood in an attempt to optimize rehabilitation andeduce complications. For that, a careful planning must beerformed.

onflict of interest

he authors declare no conflict of interest.

eferences

1. Brånemark PI. Surgery fixture installation. Zygomaticus fixtureclinical procedures. 1a ed. Gotemburgo, Suécia: Nobel Biocare,AB; 1998.

2. Weicher T, Schettler D, Mohr C. Titanium implants in the zygomaas retaining elements after hemimaxillectomy. Int J Oral Max-illofac Implants. 1997;12:211---4.

3. Stella J, Warner M. Sinus slot technique for simplification andimproved orientation of zygomaticus dental implants: a techni-cal note. Int J Oral Maxillofac Implants. 2000;15:889---93.

4. Duarte lR, Nary Filho H, Francischone C. Fixacões zigomáticas:uma excelente alternativa cirúrgica para maxila severamentereabsorvida. Revisão de literatura e estágio científico atual.Implant News. 2004;1:477---86.

5. Duarte LR, Peredo LG, Nary Filho H. Reabilitacão da maxila atró-fica utilizando quatro fixacões zigomáticas em sistema de cargaimediata. Implant News. 2004;1:45---50.

6. Zwahlen RA, Grätz KW, Oechslin CK, Studer SP. Survival rate ofzygomatic implants in atrophic or partially resected maxillaeprior to functional loading: a retrospective clinical report. IntJ Oral Maxillofac Implants. 2006;21:413---20.

7. Davó R. Zygomatic implants placed with a 2-stage procedure: a5-year retrospective study. Eur J Oral Implantol. 2009;2:115---24.

8. Kahnberg KE, Henry PJ, Hirsch JM, Ohrnell LO, AndreassonL, Brånemark PI, et al. Clinical evaluation of the zygomaimplant: 3-year follow-up at 16 clinics. J Oral Maxillofac Surg.2007;65:2033---8.

9. Hervé R, Raphael O. Intracerebral penetration of a zygomaticdental implant and consequent therapeutic dilemmas: casereport. Int J Oral Maxillofac Implants. 2010;25:416---8.

0. Malevez C, Abarca M, Durdu F, Daelemans P. Clinical outcome of103 consecutive zygomatic implants: a 6---48 months follow-upstudy. Clin Oral Implants Res. 2004;15:18---22.

1. Becktor JP, Isaksson S, Abrahamsson P, Sennerby L. Evaluationof 31 zygomatic implants and 74 regular dental implants used in16 patients for prosthetic reconstruction of the atrophic max-illa with cross-arch fixed bridges. Clin Implant Dent Relat Res.2005;7:159---65.

2. Landes CA. Zygoma implant-supported midfacial prostheticrehabilitation: a 4-year follow-up study including assessment

c implant: Late complications in a period of 12 years of http://dx.doi.org/10.1016/j.piro.2016.03.007

of quality of life. Clin Oral Implants Res. 2005;16:313---25.3. Aparicio C, Ouazzani W, Garcia R, Arevalo X, Muela R, Fortes V. A

prospective clinical study on titanium implants in the zygomaticarch for prosthetic rehabilitation of the atrophic edentulous

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ARTICLEIRO-96; No. of Pages 6

maxilla with a follow-up of 6 months to 5 years. Clin ImplantDent Relat Res. 2006;8:114---22.

4. Farzad P, Andersson L, Gunnarsson S, Johansson B. Rehabilita-tion of severely resorbed maxillae with zygomatic implants: anevaluation of implant stability, tissue conditions, and patients’opinion before and after treatment. Int J Oral MaxillofacImplants. 2006;21:399---404.

5. Chrcanovic BR, Abreu MH. Survival and complications of zygo-matic implants: a systematic review. Oral Maxillofac Surg.2013;17:81---93.

6. Al-Nawas Wegener J, Bender C, Wagner W. Critical soft tis-sue parameters of the zygomatic implants. J Clin Periodontol.2004;31:497---500.

7. De Freitas J, Lucente FE. The Caldwell-Luc procedure:institutional review of 670 cases 1975---1985. Laryngoscope.1988;12:1297---300.

8. Ikeda K, Hirano K, Oshima T, Shimomura A, Suzuki H, SunoseH, et al. Comparison of complications between endoscopicsinus surgery and Caldwell-Luc operation. Tohoku J Exp Med.

Please cite this article in press as: Filho HN, et al. Zygomatiexperience. Rev Clin Periodoncia Implantol Rehabil Oral. 2016.

1996;180:27---31.9. Petruson B. Sinuscopy in patients with titanium implants in

the nose and sinuses. Scand J Plast Reconstr Surg Hand Surg.2004;38:86---93.

2

PRESSH.N. Filho et al.

0. Bedrossian E, Tumpel L 3rd, Beckely ML, Indresano T. Thezygomatic implants: preliminary data on treatment of severelyresorbed maxillae. A clinical report. Int J Oral MaxillofacImplants. 2002;17:861---5.

1. Brånemark PI, Gröndahl K, Ohrnell LO, Nilsson P, PetrusonB, Svensson B, et al. Zygoma fixture in the management ofadvanced atrophy of the maxilla: technique and long-termresults. Scand J Plast Reconstr Surg Hand Surg. 2004;38:70---85.

2. Hirsch JM, Ohrnell LO, Henry PJ, Andreasson l, brånemarkPI, Chiapasco MA. Clinical evaluation of the zygoma fixture:one year of follow-up at 16 clinics. J Oral Maxillofac Surg.2004;62:22---9.

3. Jemt T, Lekholm U. Implant treatment in edentulous maxillae:a 5-year follow-up report on patients with different degreesof jaw resorption. Int J Oral Maxillofac Implants. 1995;10:303---11.

4. Eger DE, Gunsolley JC, Feldman S. Comparison of angled andstandard abutment and their effect on clinical outcomes: apreliminary report. Int J Oral Maxillofac Implants. 2000;15:

c implant: Late complications in a period of 12 years of http://dx.doi.org/10.1016/j.piro.2016.03.007

819---23.5. Nary Filho H, Ilg JP. Atrofia severa da maxila. In: Dinatto

JC, Polido WD, editors. Implantes Osseointegrados, Cirurgia ePrótese. São Paulo: Artes Médicas; 2001. p. 343---72.