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I case report _ guided surgery

_Introduction

Restoration-driven implant placement is a keyfactor for successful implant therapy. In this context, Computer-assisted Implant Surgery (CAIS) offers an additional instrument for treatment planning, surgical placement and prosthetic reha-bilitation in an interdisciplinary team approach.

The continuous technological progress in boththe computer-based development and the den-tal manufacturing process ensures new opportuni-ties in the clinical workflow. DWOS, in associationwith Straumann, offers a powerful combination ofCAIS with the established GonyX System. In addi-tion, a fully digital pathway in a model-free ap-proach or a combination of these workflows is nowpossible.

This case presentation displays insights into thecurrent processes of CAIS with an outlook on futureimprovements in the digital implant workflow.

_Interdisciplinary Planning

CoDiagnostiX ensures the planning of the im-plant position using Cone Beam Computed Tomo -graphy (CBCT) with DICOM data (Digital Imagingand Communications in Medicine) and the subse-quent transfer of the virtual situation into realitywith an interdisciplinary team approach includingthe restorative dentist, the implant surgeon and the dental technologist.

The conventional workflow includes the fab -rication of a dental set-up, a radiographic templateand the secondary adaptation to a surgical tem-plate. Here, the fully digital process represents a further development: computer-assisted planningof the implant position by means of a virtually con-structed prosthetic set-up and on-screen designingof an implant-guided template. The number of op-erational steps is shortened significantly comparedto the conventional workflow.

Moreover, costly and time-intensive prepara-tions can be avoided for the patient in advance ofthe CBCT. In addition, existing 3-D radiographic images should already be used, if possible.

The clinical case presentation demonstratesstep-by-step the fully digital implant workflow withCAIS, including intraoral surface scanning andprosthetic rehabilitation in a five-step approach(Fig. 1).

CAD/CAM4_2013

Digital implant dentistry—a workflow in five stepsAuthors_ Dr Tim Joda & Prof. Daniel Buser, Switzerland

Fig. 1

Fig. 2b Fig. 2cFig. 2a

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Step 1

3-D radiographic diagnostics are performedwithout any template. An intraoral surface scan(iTero™) supplements the imaging sequence. Thescan allows the generation of a high-resolutionportable STL file (Surface Tesselation Language) ofthe intraoral patient situation (Figs. 2a–c).

Step 2

The DICOM data and the STL file are implementedand superimposed in the CoDiagnostiX planningsoftware. A virtual set-up of the prosthetic re -construction, as well as a surgical template with op timal 3-D implant positioning can be realized using a restoration-driven backward planning con-cept, whilst considering the individual anatomicalsitu ation (Fig. 3).

Once the planning phase is finished in CoDiagnostiX, a 3-D printer can plot the virtual construction of the surgical template with the rapidprototyping technique without the need of any phy -sical model. Finally, CoDiagnostiX delivers an in di -vidual drilling protocol with sequenced CAIS instru-ments for a safe 3-D implant placement (Fig. 4a & b).

_Surgery

Step 3

Prior to implant surgery, the plotted template ischecked for a gap-free fit in the patient’s mouth.Built-in viewing windows adjacent to the implantsite and in contralateral position improve the level ofcontrol that can be clinically achieved (Figs. 5a & b).After anesthesia and soft tissue punch, the corticalbone is perforated with a round bur in central position.

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case report _ guided surgery I

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Fig. 4a Fig. 4bFig. 3

Fig. 6bFig. 6a

Fig. 5bFig. 5a

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I case report _ guided surgery

Afterwards, the preparation of the implant bed ismade, successively using specialized guiding toolsand corresponding spiral drills that could clinicallybe inserted into the slots of the sleeves. A flaplessapproach is only recommended if the local boneanatomy is adequate in volume, and if a wide bandof keratinized mucosa is present at the implant site(Figs. 6a & b).

An implant depth gauge is placed after the first drilling to confirm accurate positioning of the osteotomy. Early error detection can be noticed atthis initial stage and a possible deviation of the pro-posed implant position must be corrected manually(Figs. 7a & b).

Afterwards, the guided drill sequence can then becontinued. The present bone density will determine,if thread cutting is necessary, or not (Figs. 8a–c). Theplacement of up to RN/RC-diameter-implants canbe made directly, guided via the integrated 5 mmdrill sleeve. Implants with larger diameters must

be inserted manually by guidance of the finalizeddrill bed. The post-operative radiograph shows thecorrect prosthetic positioning of the implant withsufficient safety distance from the Nervus alveolarisinterior and the adjacent dentition (Figs. 9a–c).

_Prosthodontics

Step 4

Based on an additional intraoral optical im -pression using an implant scanbody, a second STL file can be created immediately after implantplacement. This STL file is then also implementedinto CoDiagnostiX. Differences between the actualimplant location and the virtually planned positioncan be correlated and compared (Figs. 10a–c).

Moreover, the implant-supported prostheticsuprastructure can be designed and fabricated dur-ing the healing period. All the necessary informationof the actual implant position is still included in

CAD/CAM4_2013

Fig. 7a

Fig. 9b Fig. 9cFig. 9a

Fig. 8b Fig. 8cFig. 8a

Fig. 7b

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I case report _ guided surgery

the second STL file at this time. The CAD/CAM-fab-ricated monolithic implant crown can be finalizedbased on the virtually generated patient situation in a model-free technical approach.

Step 5

The full-contour reconstruction is tried out andreveals a functional treatment outcome without theneed for any interproximal or occlusal correctionsand a pleasing clinical appearance (Figs. 11a–c).

_Summary

Further development in digital implant dentistryapproximates the interfaces of surgical and pros-thetic treatment steps: from the virtual planning,plotted on a guidance template manufacturing, tothe CAD/CAM-based design, including productionof the final prosthetic reconstruction.

As a part of the whole digital sequence, CAIS offers an additional tool in the interdiscipli-nary treatment planning. Precise and predictabletreatment results can be implemented with this approach under consideration of the individual patient situation. In the full digital workflow, theoverall treatment time is shortened and technicalwork steps can be saved in advance in a total of five stages with only three patient appointments.This novel process ensures the virtual constructionand fabrication of surgical templates with a 3-Dprinter as well as the fabrication of monolithic im -plant-supported reconstructions using CAD/CAM- technology without the need for any physical mod -

els. This approach has the potential to further simplify clinical procedures in implant patients. Thetechnique needs to be examined in clinical studies.In addition, clinical experience will demonstratewhat percentage of the patient pool will benefitfrom this exciting technology.

_Acknowledgements

The authors would like to thank the dental tech-nologist Isabell Wiestler for the manufacturing ofthe implant-supported reconstruction and AlbrechtSchnappauf for his technical support._

iTero is a trademark of Align Technology Inc., San Jose/USA

CAD/CAM4_2013

Dr Tim Joda, DMD, MSc Division of Fixed ProsthodonticsSchool of Dental Medicine,University of Berne, Switzerland

Prof. Daniel Buser, DMD, PhDDepartment of Oral SurgerySchool of Dental Medicine,University of Berne, Switzerland

CAD/CAM_about the authors

Fig. 11b Fig. 11cFig. 11a

Fig. 10b Fig. 10cFig. 10a

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