research accuracy evaluation of computed tomography ... et al, 2010 accurac… · various...

Accuracy Evaluation of ComputedTomography–DerivedStereolithographic Surgical Guides inZygomatic Implant Placement inHuman CadaversBruno R. Chrcanovic, DDS*Davidson R. Oliveira, MSAntonio L. Custodio, PhD

Presurgical planning is essential to achieve esthetic and functional implants. For implant

planning and placement, the association of computer-aided design (CAD) and computer-

aided manufacturing (CAM) techniques furnishes some advantages regarding tridimensional

determination of the patient’s anatomy and fabrication of both anatomic models and

surgical guides. The goal of this clinical study was to determine the angular deviations

between planned and placed zygomatic implants using stereolithographic surgical guides in

human cadavers. A total of 16 zygomatic implants were placed, 4 in each cadaver, with the

use of stereolithographic (SLA) surgical guides generated by computed tomography (CT). A

new CT scan was made after implant insertion. The angle between the long axis of the

planned and actual implants was calculated. The mean angular deviation of the long axis

between the planned and placed implants was 8.06 6 6.40 (mean 6 SD) for the anterior-

posterior view, and 11.20 6 9.75 (mean 6 SD) for the caudal-cranial view. Use of the

zygomatic implant, in the context of this protocol, should probably be reevaluated because

some large deviations were noted. An implant insertion guiding system is needed because

this last step is carried out manually. It is recommended that the sinus slot technique should

be used together with the CT-based drilling guide to enhance final results. Further research

to enhance the precision of zygomatic implant placement should be undertaken.

Key Words: zygomatic implant, atrophic maxilla, image-based surgery,stereolithography, customized drill guides

INTRODUCTION

Presurgical planning is essential

to achieve excellent esthetic and

functional outcomes with dental

implants. Many conflicting vari-

ables such as the mandibular

canal, maxillary sinus, and adjacent teeth

Pontifıcia Universidade Catolica de Minas Gerais, MinasGerais, Brazil.* Corresponding author, e-mail: [email protected]: 10.1563/AAID-JOI-D-09-00074

RESEARCH

Journal of Oral Implantology 345

must be considered before implant surgery

is performed. Practitioners generally have

used conventional dental radiographs (pan-

oramic and periapical radiographs)1 and

conventionally fabricated surgical guides2,3

for implant placement. The panoramic radio-

graphs that are commonly used in implant

treatment planning are limited by their

characteristics of magnification and distor-

tion, as well as by lack of sharpness of the

image. Also, a panoramic radiograph is a 2-

dimensional image that provides little in-

formation about the buccal-lingual width of

the jawbones.4 The surgical guides conven-

tionally fabricated on diagnostic stone casts

do not provide information about the

varying thicknesses of the mucosa, the

topography of underlying bone, or the

anatomic structures, and they do not remain

stable during surgery because of reflected

soft tissue.2

Computed tomography (CT) is a helpful

tool for implant patients, especially in situa-

tions with anatomic limitations, insufficient

bone dimensions, and poor bone density.5,6

The use of CT imaging enhances the

correlation between implant planning and

actual implant placement compared with

conventional radiographic methods.7

Currently, few software systems use CT

scans to aid in planning surgery and to

produce surgical drilling guides. These

guides are manufactured in such a way that

they match the location, trajectory, and

depth of the planned implant with a high

degree of precision. As the dental practi-

tioner places the implants, the guides

stabilize the drilling by restricting the de-

grees of freedom of the drill trajectory and

depth. Earlier studies concluded that 3-

dimensional (3D) planning resulted in im-

plant positioning with improved biome-

chanics and esthetics.8–10 Use of such a

system usually prevents complications such

as mandibular nerve damage, sinus perfora-

tions, fenestrations, or dehiscences.8,11 Also,

computer-aided design (CAD) and compu-

ter-aided manufacturing (CAM) software may

improve the association between dental

implant planning and insertion, in terms of

3D determination of the patient’s jaw

anatomy and fabrication of both anatomic

models and surgical guides.8,12–14

Some studies have recently illustrated

promising results with stereolithographic

(SLA) surgical guides.12,15–18 The SLA consists

of a vat containing a liquid photopolymer-

ized resin.18 A laser mounted on top of the

vat moves in sequential cross-sectional

increments of 1 mm, corresponding to the

slice intervals specified during the CT for-

matting procedure. The laser polymerizes

the surface layer of the resin on contact.

Once the first slice is completed, a mechan-

ical table immediately below the surface

moves down 1 mm, carrying with it the

previously polymerized resin layer of the

model. The laser subsequently polymerizes

the next layer adjacent to the previously

polymerized layer.18 In this manner, a

complete SLA model of the maxilla and the

surgical guides is created.

Restoration of the atrophied edentulous

maxilla poses a great dilemma to the oral

and maxillofacial surgeon and the restorative

dentist. Patients with adequate maxillary

bone are ideal candidates for implants, but

they are the exception. Patients with mod-

erate to severe atrophy challenge the

surgeon to discover alternative ways to use

existing bone or resort to augmenting the

patient with autogenous or alloplastic bone

materials.

Various techniques have been described

for approaching the atrophic maxilla, includ-

ing the use of tilted implants in the parasinus

region19–22 and implants in the pterygoid

apophysis,23,24 grafting of the maxillary sinus

floor,25,26 and the use of short, wide im-

plants,27,28 different types of grafts,29–31 and

zygoma implants.32–40 The incidence of

implant loss in the severely resorbed pos-

Accuracy of 3D CT-Based Surgical Guides

346 Vol. XXXVI/No. Five/2010

terior maxilla is approximately 15% without a

sinus bone graft.41

The zygoma implant has been designed

by Branemark33,34,42 for those situations in

which there is insufficient bone in the upper

jaw, which would otherwise require onlay or

inlay (sinus) bone grafts. Zygomatic bone is

excellent for the anchorage of implants, as

has been validated in several anatomic

studies.43–46 These authors agree that the

quality of zygomatic bone is superior to that

of the posterior maxilla, and the importance

of the cortical portion of the zygomatic bone

for anchoring implants43 has been described.

Furthermore, zygomatic implants display

initial primary stability, because it has been

demonstrated that the zygomatic bone area

where the implant is inserted has wider and

thicker trabecular bone.45

Implant placement in the zygoma bone,

however, can be difficult because of the

variable anatomy and varying degrees of

atrophy possible in the maxillofacial re-

gion.47 The technique is not performed

without risk because the drill path is close

to important anatomic structures. A signifi-

cant error can be induced by only a slight

deviation of the drill path direction.48

The clinical effectiveness of the use of the

drill guide and the important advantage for

aesthetic outcome have been described.49

For zygoma implants, the accuracy of the

transfer of the preoperative plan to the

surgical field is even more crucial. Given an

appropriate visualization, 3D CT images

provide an unparalleled depiction of the

complex anatomic topography that has to

be respected when the trajectory of a

zygoma implant is decided.

Personalized drilling templates may be

fabricated by a computer-based transfer

from the available 3D CT planning data50;

this allows incorporation of all predeter-

mined biomechanical, esthetic, and ana-

tomic factors during the surgical proce-

dure.

The goal of this clinical study was to

determine the angular deviations between

planned and placed zygomatic implants in

human cadavers by using SLA-based drilling

guide technology.

MATERIALS AND METHODS

The study protocol was approved by the

Institutional Ethics Committee of the Federal

University of Minas Gerais. Four human

cadavers were considered for the study.

Standardized CT scanning procedures

were followed for each cadaver and were

performed by the same radiologist operating

a CT machine (Classic i-CAT, Imaging

Sciences International, Hatfield, Pa). CT data

for each cadaver were imported to the

planning software (Dental Slice software,

BioParts Prototipagem Biomedica, Brasılia,

Brazil), allowing the surgical team to simu-

late implant placement on the 3D model.

While taking into consideration the anatomic

structures, the surgical team interactively

simulated the position of the implant on

each plane. Once the implant is planned, its

angulation can still be adjusted and its

dimensions adapted to obtain the optimal

position of the implant (Figure 1). The

implant is directed in a lateral and upward

direction with an angulation of 45 degrees

from a vertical axis. The end point has to

encroach into the zygomatic bone, which

has a thickness of about 10 mm. The zygoma

implant thus follows an intrasinusal trajec-

tory. After initial positioning of the implant,

several minor adjustments can be made until

the implant is surrounded by bone at its

entry and end points, to ensure that the

intermediate part does not perforate the

anterior maxillary wall. A rapid prototyping

machine based on the principle of stereo-

lithography was used to fabricate the SLA

models and guides. The aim was to create an

individualized drill guide that is suited to the

bone profile.

Chrcanovic et al


The SLA machine also read the diameter

and angulation of the simulated implants

and selectively polymerized resin around

them, forming a cylindrical guide corre-

sponding to each implant. Surgical grade

stainless steel tubes were attached to the

cylindrical guide. To prevent lateral angula-

tion of the drill during the drilling process,

drill guides (made by Peclab Ltda, Belo

Horizonte, Brazil) that perfectly adapted to

the stainless steel tubes were made (Fig-

ure 2). Drilling of the zygoma implants was

performed with the use of 4 drills. Conse-

quently, 4 sets of drill guides were provided.

The inner diameter of the drill guides is

0.3 mm greater than the diameter of the

corresponding drill. The angulation and

mesiodistal and buccolingual positioning of

each implant as planned with the use of 3D

computer simulation software were trans-

ferred to the SLA surgical guide.

The SLA bone-supported surgical guide

type was used. The surgical drill guide was

fitted onto the maxilla and was fixated with 2

or 3 osteosynthesis screws (10.0 3 1.5 mm).

The drilling procedures were performed with

the use of appropriate drills for each

corresponding implant according to the

manufacturer’s instructions. A total of 16

zygomatic implants were placed (SIN Sis-

tema de Implante, Sao Paulo, Brazil), all

4.0 mm of diameter ranging from 37.5 to

57.5 mm in length. Four implants were

placed in each cadaver, 2 in the canine

region, 2 in the first molar region, with the

use of SLA surgical guides generated from

CT. A new CT scan was made for each

cadaver after implant insertion.

FIGURE 1. The 3-dimensional computed tomography (CT) planning system. Axial, transversal, panoramic,and tridimensional CT slices are possible. Clinically relevant covisualization can be obtained.

FIGURE 2. Drill guides to every corresponding drillwere made to perfectly adapt into the cylindricalguide.



Adobe Photoshop Elements software

(version 2.0, Adobe Systems Incorporated,

San Jose, Calif) was used to match images of

planned and placed implants, and their

positions and axes were compared. Pre-

operative and postoperative CT scans in

anterior-posterior (Figure 3) and caudal-cra-

nial (Figure 4) views were aligned to allow

observation of the superposition of anatomic

markers. The angle between the long axes of

the planned and the actual implant (Fig-

ures 5 and 6) was calculated with the

VistaMetrix software (version 1.36.0, Skill-

Crest, Tucson, Ariz). Basic descriptive statistics

was employed to analyze the data obtained

using standard software (Excel, Microsoft

Corporation, Redmond, Wash).

RESULTS

In the right posterior implant of cadaver 4

(C4), the angular deviation between planned

and actual implant position in an anterior-

posterior view was 0.35 degrees, the smallest

deviation, but the left posterior implant of

cadaver 3 (C3) in a caudal-cranial view

showed the largest deviation (37.60 de-

grees). A more detailed presentation of the

angular deviation between planned and

placed implants in an anterior-posterior and

a caudal-cranial view in the 4 cadavers is

found in the Table.

The mean angular deviation of the long

axis between planned and placed implants

was 8.06 6 6.40 (mean 6 SD) for the

anterior-posterior view, and 11.20 6 9.75

(mean 6 SD) for the caudal-cranial view.

Minimal and maximal values for the anterior-

posterior view were 0.35 degrees and 21.20

degrees, and 0.76 degrees and 37.60 degrees

for the caudal-cranial view.

DISCUSSION

The strength of the anchorage in the

zygoma compensates for the bad quality of

the bone, mostly type IV in the posterior

maxilla. From a biomechanical point of view,

it has been demonstrated that if the zygoma

fixtures are connected to the anterior

FIGURES 3–6. FIGURE 3. Preoperative and postoperative computed tomography (CT) scans in an anterior-posterior view were aligned while the superposition of anatomic markers was observed. FIGURE 4.Preoperative and postoperative CT scan superposition in a caudal-cranial view. FIGURE 5. Superpositionof the planned and placed implants in a caudal-cranial view (cadaver 4). FIGURE 6. Superposition of theplanned and placed implants in an anterior-posterior view (cadaver 1).

Chrcanovic et al


implants, masticatory forces applied to the

fixed prosthesis are transferred to the

zygoma.44

The CT scanning template is the principal

key to the system because it permits the

transfer of the predetermined prosthetic

setup to the actual implant planning. The

scanning template is an exact replica of the

desired prosthetic outcome; this allowed

both surgeon and restorative dentist to base

implant planning on the desired prosthetic

outcome. The treatment plan is thus driven

by the prosthetic end result.16,51

Other studies have assessed the magni-

tude of error in transferring the planned

position of implants from CT scans to a

surgical guide. In the in vitro study by

Besimo et al,52 the deviation between the

positions of the apex of proposed implants

on cross-sectional CT images and on the

corresponding study cast was measured at

77 sites. Transfer errors for the maxilla and

mandible were 0.6 6 0.4 mm and 0.3 6

0.4 mm. However, investigators concluded

that the transfer errors noted in their study

were not clinically relevant because other

factors involved in transferring positional

and angular measurements from CT images

to the actual surgical area may result in

greater errors. Another in vitro study by

Sarment et al12 included 50 implants placed

into 5 epoxy resin edentulous mandible

models. Each epoxy resin mandible received

5 implants on each side. On the right side, 5

implants were inserted using a conventional

surgical guide, whereas on the left side, 5

implants were inserted using an SLA surgical

guide. When compared with conventional

guides, significant improvements were evi-

dent in all measurements taken with SLA

surgical guides. Investigators stated that the

clinical significance of this result may be

relevant when multiple parallel distant im-

plants are placed, and where the degree of

accuracy is critical for obtaining a single

prosthetic path of insertion. Their studies,

although very relevant, were made with

normal dental implants only in the jaws,

not in the zygoma.

Van Assche et al53 placed 12 implants in 4

formalin-fixed cadaver jaws. Upon compar-

ison with the planned implants, investigators

noted average angular deviation of 2 6 0.8

degrees and mean linear deviation of 1.1 6

0.7 mm at the neck and 2 6 0.7 mm at the

apex in the placed implants. Another human

cadaver study by Van Steenberghe et al44

included 6 zygoma implants with surgical

drilling guides based on CT data. Researchers

matched preoperative CT scans with post-

operative CT scans to evaluate the deviation

between planned and placed zygoma im-

plants. Investigators reported that the angu-

lar deviations in the axis for 4 planned and

placed implants were less than 3 degrees,

whereas 1 implant showed 3.1 degrees and

the last one showed 6.9 degrees angular

deviation in the axis.

Di Giacomo et al15 evaluated the match

between the positions and axes of planned

TABLE

Angular deviations between planned and actual zygomatic implant positions in 4human cadavers*

Cadaver C1 C2 C3 C4

View A-P C-C A-P C-C A-P C-C A-P C-C

RegionFirst right superior molar 12.30 4.20 1.46 14.80 6.66 14.20 0.35 8.59Right canine 2.70 14.70 4.22 18.30 11.20 0.76 5.05 6.30First left superior molar 3.62 3.14 1.54 24.70 21.20 37.60 9.88 6.39Left canine 8.79 5.74 4.99 14.10 18.50 1.22 16.50 4.41

*A-P indicates anterior-posterior view; C-C, caudal-cranial view.



and inserted implants when an SLA surgical

guide was used. They inserted 21 implants in

4 patients using 6 SLA surgical guides and CT

data, measuring the deviation between

planned and inserted implants. Investigators

noted an average angular deviation of 7.25

6 2.67 degrees between planned and

inserted implant axes. This average angular

deviation was higher in the study of Vrielinck

et al48—10.46 degrees (range: 0–21.0 de-

grees)—also an in vivo study. Other in vivo

studies tried to determine deviations in the

position and inclination of planned and

placed implants using SLA surgical guides

and to compare 3 different types (tooth-

supported, bone-supported, and mucosa-

supported) of SLA surgical guides.18 Under

the guidelines of this study, CT-derived SLA

surgical guides supported by tooth, bone, or

mucosa provided a precise tool for both

flapless and conventional flap implant inser-

tion. Naitoh et al54 found angular deviations

between planning and placement ranging

from 0.5 to 14.5 degrees, with an average of

5.0 degrees, using teeth-supported conven-

tional guides. The CT data were used to

transfer only the position and/or inclination

of the implants to a laboratory-made tem-

plate placed on working plaster models.

The main goal of the study was to

evaluate the possibilities of skeletally sup-

ported drill guides for zygomatic implant

placement in patients with severely atrophic

maxillas, while still providing a predictable,

permanent, and successful treatment result.

The mean angular deviation of the long axis

between planned and placed implants was

8.06 6 6.40 (mean 6 SD) for the anterior-

posterior view, and 11.20 6 9.75 (mean 6

SD) for the caudal-cranial view. This aim was

not completely met by this treatment con-

cept, in terms of angular deviations between

planned and placed implants. Despite the

fact that deviations between planned and

placed implants could be quite substantial,

in some cases this may not affect the ability

of the restorative dentist to design and

fabricate a prosthetic suprastructure onto

these deviated implants. Deviations with

good clinical results also occurred, as can

be observed with the left side on cadaver 1

(Figures 7 and 8).

It is not easy to make direct comparisons

between in vitro studies and the present

human subject, as in vitro studies provide

improved control of all contributing pa-

rameters. However, it was observed as large

angular deviations, probably because of

FIGURES 7 AND 8. FIGURE 7. Good clinical results. Left side of cadaver 1. FIGURE 8. Good clinical results. Leftside of cadaver 1.

Chrcanovic et al


poor fit of the surgical guide, between other

causes. The precision of the whole procedure

depends largely on the ability to position

accurately the drill guide on top of the bone,

and to maintain that stable position during

the whole procedure. The difference of

osteosynthesis screws in fixing the surgical

guide onto the maxilla bone can also have

an important role. In this study, 1 mm length

screws were used—a half length when

compared with the study of Vrielinck et

al.48 The number of screws was also lesser: 2

or 3 against 4 or 5 in the study of Vrielinck et

al.48 Asymmetric distribution of the screws or

uneven tightening of the screws could bring

the drilling template out of balance. Further-

more, a certain error is induced as the

diameter of the steel tubes is slightly larger

than the drill diameter. Finally, the largest

error is probably due to the fact that the final

step in the procedure is carried out manu-

ally. Implant placement cannot be done

through the surgical drill guide because of

present mechanical limitations. The drill

guide, therefore, has to be removed before

the implant is actually inserted, leaving the

possibility of additional deviation.

The original Branemark protocol creates a

sinus window technique for placement of

these zygoma dental implants. Stella and

Warner’s55 published ‘‘sinus slot technique’’

significantly simplified the original Brane-

mark protocol. The ‘‘sinus slot’’ is a guide

window made directly through the buttress

wall of the maxilla, whereby the zygoma

implant is guided through the maxilla to the

apex insertion at the junction of the lateral

orbital rim and the zygomatic arch. This

lateral sinus slot allows greater potential for

bone-to-implant interface because of this

lateral position, and eliminated the sinus

window and sinus lining elevation for place-

ment of the implant. This lateral window

allows direct vision to the base of the

zygoma bone and helps control the implant

position by direct vision.56 The fact that we

have done these surgeries in a cadaver

without direct vision through the maxillary

sinus may also have influenced the results.

Moreover, some deviation may occur

when the actual implant entry point is

considered compared with initial treatment

planning. This may be due to the brittle and

soft consistency of bone in the maxillas with

severe bone atrophy.48

On the left side of cadaver number 3, 1

implant emerged in the infratemporal fossa

(Figure 9) and the other one inside the orbit

FIGURES 9 AND 10. FIGURE 9. Poor clinical results. One implant emerged in the infratemporal fossa ofcadaver 3. FIGURE 10. Poor clinical results. One implant emerged inside the orbital cavity of cadaver 3.



(Figure 10). This great deviation of course

occurred because of the long length of the

zygomatic implants (37.5–57.5 mm)—3 to 4

times that of oral implants—which means

that even minute angular deviations lead to

important discrepancies at the extremity.44

According to Vrielinck et al,48 it should be

noted that the common practice today is to

position zygoma implants without any form

of physical control of the drilling trajectory.

However, care has to be taken to ensure a

proper mesiocranial direction for the im-

plant. If the implant is planned too much

laterally, it would emerge in the infratem-

poral fossa. If, on the contrary, it is planned

too much mesially it would end up in the

nasopharynx or the sphenoid sinus. If the

inclination of the implant is too much in the

cranial direction, it would enter the fossa

pterygopalatina. For an implant directed too

much horizontally, no bony structures will be

encountered.48 Based on the dimensional

variability of the zygoma bone, such errors

might, even with accurate 3D CT-based

planning and transfer, create potential dan-

gers.

It must be emphasized that in the

preliminary feasibility study, implant plan-

ning may be done solely on the basis of

available bone volume (ie, implant planning

may not take into account information

conveyed through a preoperative prosthetic

set-up, because the quantity of present bone

may be minimal because of the atrophy).

Consider that the ‘‘wrong’’ implants position

should not affect the ability to design and

fabricate a prosthetic suprastructure onto

these deviated implants, despite the angular

deviation.

CONCLUSIONS

The results of this study demonstrate that

the use of the zygomatic implant, in the

context of this protocol, should probably be

reevaluated because some large deviations

were noted. An implant insertion guiding

system is needed because this last step is

carried out manually. It is recommended that

utilization of the sinus slot technique

together with the CT-based drilling guide

would enhance the final results. The tridi-

mensional CT is a helpful tool for patient

candidates to zygomatic implants, because

the drill path is close to important anatomic

structures. The reported results may be

surprising and should stimulate further

research to enhance the precision of zygo-

matic implant placement, even given that

better results were obtained by former

studies.

ABBREVIATIONS

CAD: computer-aided design

CAM: computer-aided manufacturing

CT: computed tomography

SLA: stereolithographic

3D: three-dimensional

REFERENCES

1. Gahleitner A, Watzek G, Imhof H. Dental CT:imaging technique, anatomy, and pathologic condi-tions of the jaws. Eur Radiol. 2003;13:366–376.

2. Lal K, White GS, Morea DN, Wright RF. Use ofstereolithographic templates for surgical and prostho-dontic implant planning and placement. Part I. Theconcept. J Prosthodont. 2006;15:51–58.

3. Pramono C. Surgical technique for achievingimplant parallelism and measurement of the discrep-ancy in panoramic radiograph. J Oral Maxillofac Surg.2006;64:799–803.

4. Reddy MS, Mayfield-Donahoo T, Vanderven FJ,Jeffcoat MK. A comparison of the diagnostic advan-tages of panoramic radiography and computedtomography scanning for placement of root formdental implants. Clin Oral Implants Res. 1994;5:229–238.

5. Jacobs R, Adriansens A, Verstreken K, Suetens P,Van Steenberghe D. Predictability of a three-dimen-sional planning system for oral implant surgery.Dentomaxillofac Radiol. 1999;28:105–111.

6. Siessegger M, Schneider BT, Mischkowski RA,et al. Use of an image-guided navigation system indental implant surgery in anatomically complex opera-tion sites. J Craniomaxillofac Surg. 2001;29:276–281.

7. Jacobs R, Adriansens A, Naert I, Quirynen M,Hermans R, Van Steenberghe D. Predictability ofreformatted computed tomography for pre-operative

Chrcanovic et al


planning of endosseous implants. DentomaxillofacRadiol. 1999;28:37–41.

8. Verstreken K, van Cleynenbreugel J, Marchal G,Naert I, Suetens P, van Steenberghe D. Computer-assisted planning of oral implant surgery: a 3-dimen-sional approach. Int J Oral Maxillofac Implants. 1996;11:806–810.

9. Sanna AM, Molly L, van Steenberghe D. Im-mediately loaded CAD-CAM manufactured fixed com-plete dentures using flapless implant placementprocedures: a cohort study of consecutive patients. JProsthet Dent. 2007;97:331–339.

10. Wittwer G, Adeyemo WL, Schicho K, BirkfellnerW, Enislidis G. Prospective randomized clinical compar-ison of 2 dental implant navigation systems. Int J OralMaxillofac Implants. 2007;22:785–790.

11. Nickenig HJ, Eitner S. Reliability of implantplacement after virtual planning of implant positionsusing cone beam CT data and surgical (guide)templates. J Craniomaxillofac Surg. 2007;35:207–211.

12. Sarment DP, Sukovic P, Clinthorne N. Accuracyof implant placement with a stereolithographic surgicalguide. Int J Oral Maxillofac Implants. 2003;18:571–577.

13. Van Steenberghe D, Glauser R, Blomback U, etal. A computed tomographic scan-derived customizedsurgical template and fixed prosthesis for flaplesssurgery and immediate loading of implants in fullyedentulous maxillae: a prospective multicenter study.Clin Implant Dent Relat Res. 2005;7(suppl):S111–S120.

14. Marchack CB. CAD/CAM-guided implant sur-gery and fabrication of an immediately loaded pros-thesis for a partially edentulous patient. J Prosthet Dent.2007;97:389–394.

15. Di Giacomo GA, Cury PR, de Araujo NS, SendykWR, Sendyk CL. Clinical application of stereolitho-graphic surgical guides for implant placement: pre-liminary results. J Periodontol. 2005;76:503–507.

16. Rosenfeld AL, Mandelaris GA, Tardieu PB.Prosthetically directed implant placement using com-puter software to ensure precise placement andpredictable prosthetic outcomes. Part 3: stereolitho-graphic drilling guides that do not require boneexposure and the immediate delivery of teeth. Int JPeriodontics Restorative Dent. 2006;26:493–499.

17. Van de Velde T, Glor F, De Bruyn H. A modelstudy on flapless implant placement by clinicians with adifferent experience level in implant surgery. Clin OralImplants Res. 2008;19:66–72.

18. Ozan O, Turkyilmaz I, Ersoy AE, McGlumphy EA,Rosenstiel SF. Clinical accuracy of 3 different types ofcomputed tomography-derived stereolithographic sur-gical guides in implant placement. J Oral MaxillofacSurg. 2009;67:394–401.

19. Mattsson T, Kondell PA, Gynther GW, FredholmU, Bolin A. Implant treatment without bone grafting inseverely resorbed edentulous maxillae. J Oral MaxillofacSurg. 1999;57:281–287.

20. Krekmanov L. Placement of posterior mandib-ular and maxillary implants for improved prosthesissupport. Int J Oral Maxillofac Implants. 2000;15:722–730.

21. Krekmanov L, Kahn M, Rangert B, Lindstrom H.Tilting of posterior mandibular and maxillary implantsfor improved prosthesis support. Int J Oral MaxillofacImplants. 2000;15:405–414.

22. Aparicio C, Perales P, Rangert B. Tilted implantsas an alternative to maxillary sinus grafting: a clinical,

radiologic, and periotest study. Clin Implant Dent RelatRes. 2001;3:39–49.

23. Fernandez Valeron J, Fernandez Velazquez J.Placement of screw-type implants in the pterygomax-illary-pyramidal region: a surgical procedure andpreliminary results. Int J Oral Maxillofac Implants.1997;12:814–819.

24. Balshi TJ, Wolfinger G, Balshi SF 2nd. Analysis of356 pterygomaxillary implants in edentulous arches forfixed prosthesis anchorage. Int J Oral MaxillofacImplants. 1999;14:398–406.

25. ten Bruggenkate CM, van den Bergh JP.Maxillary sinus floor elevation: a valuable pre-prostheticprocedure. Periodontol 2000. 1998;17:176–182.

26. Kahnberg KE, Ekestubbe A, Grondahl K, NilssonP, Hirsch JM. Sinus lifting procedure. I. One-stagesurgery with bone transplant and implants. Clin OralImplant Res. 2001;12:479–487.

27. Langer B, Langer L, Hermann I, Jorneus L. Thewide fixture: a solution for special bone situations and arescue for the compromised implant. Part 1. Int J OralMaxillofac Implants. 1993;8:400–408.

28. English C, Bahat O, Langer B, Sheets CG. Whatare the clinical limitations of the wide-diameter (4 mmor greater) rootform endosseous implants? Int J OralMaxillofac Implants. 2000;15:293–296.

29. Lozada J, Proussaefs P. Clinical, radiographicand histologic evaluation of maxillary bone reconstruc-tion by using a titanium mesh and autogenous iliacgraft: a case report. J Oral Implantol. 2002;28:9–14.

30. Nystrom E, Ahlqvist J, Legrell PE, Kahnberg KE.Bone graft remodelling and implant success rate in thetreatment of the severely resorbed maxilla: a 5-yearlongitudinal study. Int J Oral Maxillofac Surg. 2002;31:158–164.

31. Malo P, Rangert B, Nobre M. All-on-4 immediatefunction concept with Branemark System implants forcompletely edentulous maxillae: a 1-year retrospectiveclinical study. Clin Implant Dent Relat Res. 2005;7(suppl1):S88–S94.

32. Breine U, Branemark PI. Reconstruction ofalveolar jaw bone: an experimental and clinical studyof immediate and preformed autologous bone grafts incombination with osseointegrated implants. Scand JPlast Reconstr Surg. 1980;14:23–48.

33. Bedrossian E, Stumpel LJ III. Immediate stabi-lization at stage II of zygomatic implants: rationale andtechnique. J Prosthet Dent. 2001;86:10–14.

34. Parel SM, Branemark PI, Ohrnell LO, Svensson B.Remote implant anchorage for the rehabilitation ofmaxillary defects. J Prosthet Dent. 2001;86:377–381.

35. Malevez C, Daelemans P, Adriaenssens P, DurduF. Use of zygomatic implants to deal with resorbedposterior maxillae. Periodontol 2000. 2003;33:82–89.

36. Nakai H, Okazaki Y, Ueda M. Clinical applicationof zygomatic implants for rehabilitation of the severelyresorbed maxilla: a clinical report. Int J Oral MaxillofacImplants. 2003;18:566–570.

37. Branemark PI, Grodahl K, Ohrnell LO, et al.Zygoma fixture in the management of advancedatrophy of the maxilla: technique and long-term results.Scand J Plast Reconstr Surg. 2004;38:70–85.

38. Ferrara ED, Stella JP. Restoration of theedentulous maxilla: the case for the zygomaticimplants. J Oral Maxillofac Surg. 2004;62:1418–1422.

39. Hirsch JM, Ohrnell LO, Henry PJ, et al. A clinicalevaluation of the zygoma fixture: one year of follow-up



at 16 clinics. J Oral Maxillofac Surg. 2004;62(9 suppl 2):22–29.

40. Malevez C, Abarca M, Durdu F, Daelemans P.Clinical outcome of 103 consecutive zygomatic im-plants: a 6–48 months follow-up study. Clin OralImplants Res. 2004;15:18–22.

41. Branemark P-I, Svensson B, Van Steenberghe D.Ten-year survival rate of fixed prosthesis on four or siximplants ad modum Branemark in full edentulism. ClinOral Implants Res. 1995;6:227–231.

42. Darle C. Branemark System Zygoma Fixture, AUnique Solution for Rehabilitation of the SeverelyResorbed Maxilla, The Zygoma Option. 2nd ed. Gothen-burg, Sweden: Nobel Biocare AB; 2000.

43. Nkenke E, Hahn M, Lell M, et al. Anatomic fordental implant placement. Clin Oral Implants Res.2003;14:72–79.

44. Van Steenberghe D, Malevez C, Van Cleynen-breugel J, et al. Accuracy of drilling guides for transferfrom three-dimensional CT-based planning to place-ment of zygoma implants in human cadavers. Clin OralImplants Res. 2003;14:131–136.

45. Kato Y, Kizu Y, Tonogi M, Ide Y, Yamane GY.Internal structure of zygomatic bone related to zygo-matic fixture. J Oral Maxillofac Surg. 2005;63:1325–1329.

46. Rigolizzo MB, Camilli JA, Francischone CE,Padovani CR, Branemark PI. Zygomatic bone: anatomicbases for osseointegrated implant anchorage. Int J OralMaxillofac Implants. 2005;20:441–447.

47. Uchida Y, Goto M, Katsuki T, Akiyoshi T.Measurement of the maxilla and zygoma as an aid ininstalling zygomatic implants. J Oral Maxillofac Surg.2001;59:1193–1198.

48. Vrielinck L, Politis C, Schepers S, Pauwels M,Naert I. Image-based planning and clinical validation ofzygoma and pterygoid implant placement in patientswith severe bone atrophy using customized drill

guides: preliminary results from a prospective clinicalfollow-up study. Int J Oral Maxillofac Surg. 2003;32:7–14.

49. Tardieu P, Philippe B. Edentement completmaxillaire avec atrophie osseuse terminale: prise encharge therapeutique. A propos d’un cas. Implant.2001;7:199–210.

50. Fortin T, Coudert JL, Champleboux G, Autot P,Lavallee S. Computer-assisted dental implant surgeryusing computed tomography. J Image Guided Surg.1995;1:53–58.

51. Rosenfeld AL, Mandelaris GA, Tardieu PB.Prosthetically directed implant placement using com-puter software to ensure precise placement andpredictable prosthetic outcomes. Part 1: diagnostics,imaging, and collaborative accountability. Int J Peri-odontics Restorative Dent. 2006;26:215–221.

52. Besimo CE, Lambrecht JT, Guindy JS. Accuracyof implant treatment planning using template-guidedreformatted computed tomography. DentomaxillofacRadiol. 2000;29:46–51.

53. Van Assche N, van Steenberghe D, GuerreroME, et al. Accuracy of implant placement based on pre-surgical planning of three-dimensional cone-beamimages: a pilot study. J Clin Periodontol. 2007;34:816–821.

54. Naitoh M, Ariji E, Okumura S, Ohsaki C, Kurita K,Ishigami T. Can implants be correctly angulated basedon surgical templates used for osseointegrated dentalimplants? Clin Oral Implants Res. 2000;11:409–414.

55. Stella JP, Warner MR. Sinus slot technique forsimplification and improved orientation of zygomaticusdental implants: a technical note. Int J Oral MaxillofacImplants. 2000;15:889–893.

56. Chow J, Hui E, Lee PKM, Li W. Zygomaticimplants—protocol for immediate occlusal loading: apreliminary report. J Oral Maxillofac Surg. 2006;64:804–811.

Chrcanovic et al


research accuracy evaluation of computed tomography ... et al, 2010 accurac… · various...

Documents