Original study - ZZI 02/2016

Template guided surgery: no longer static, but dynamic through using the positioning device Rosy

Dieter Edinger1, Thorsten Schüppstuhl2

Introduction: Previous template guided systems have the disadvantage that it is not possible to make a controlled intraoperative correction of the drilling position. Sometimes the radiograph shows only imprecisely the surface of bone with lower density. This leads to the fact that one cannot use the guidance template.

Material and methods: After exposure of the bone, by means of a marker pin attached to the guidance template the actual bone surface is indicated. The guidance template is removed from the mouth and inserted in the positioning device Rosy. The implant pointer of the positioning device is then guided through an iPad to the point marked by the pin. This preliminary implant position is then corrected through the superimposed CBCT. A corrected final guidance hole is bored in the template with the drill of the positioning device. All the settings are performed via an iPad, which improves the hygiene potential.

Results: The correction of a guidance template is possible within an acceptable time during the operation.

Conclusion: The system presented here helps in complex situations by providing controlled correction of the guidance template during the operation.

Keywords: implant; navigation; guidance template; Rosy; CAD/CAM; guided surgery; iPad

Cite as: Edinger D, Schüppstuhl T: Template Guided Surgery: no longer static, but dynamic through using the positioning device Rosy. Z Zahnärztl Implantol 2016; 32: 130–138

DOI 10.3238/ZZI.2016.0130–0138

Introduction

Recently, various systems for computer-guided implant placement have been initiated. A distinction is made here between computer-guided (static) surgery: The use of a static surgical template that reproduces the virtual implant position directly from computerized tomographic data and does not allow for intraoperative modification of the implant position; and computer-navigated (dynamic) surgery: The use of a surgical navigation system that reproduces the virtual implant position directly from computerized tomographic data and allows for intraoperative changes in the implant position [11].

The accuracy of the various systems has been proven to be clinically sufficient so that even under adverse conditions such as low remaining bone matter an application is possible [1, 2, 8, 10, 12, 13, 14, 16, 17, 18, 19, 22, 23].

However, all computer-guided (static) surgery systems have the disadvantage that a controlled intraoperative correction of the drilling position or direction is not possible. A radiograph shows only imprecisely the surface on bone with lower density [3, 9, 15, 20]. This often leads to the situation that one cannot use the template – especially in the maxilla.

As an example of a computer guided system, Edinger demonstrates the procedure for the preparation of a guidance template using a positioning device [4, 6].

A further example of a computer guided system is the SMOP Swissmeda process [21]. A CBCT is matched with the scanned surface of the planned prosthetic. Based on these data, a guidance template is planned virtually and produced through 3D printing. This method simplifies the workflow. However, in this instance as well, the guidance template is static, i.e. an intraoperative adjustment to unforeseeable variations of the bone surface is not possible.

The technology of computer-navigated (dynamic) surgery, because of intraoperative flexibility, shows significant advantages during surgery, since adjustments to unforeseen anatomical characteristics are possible [5, 7]. However, these systems have proven to be too expensive and complicated to find application in implantology.

In this paper, a method is presented in which, despite such circumstances, an adaptation of the template is possible.

Material and Method

To prepare for implantation, first an acrylic guidance template is manufactured; however, a radiopaque material is added to this acrylic so that the template can be identified on a radiograph. This guidance template is made in an articulator based on the plaster model of the jaw into which the implants are planned. The radiopaque acrylic teeth are made in the same form the implant crowns will have later.

In order to recognize where drilling for implantation must take place, the positioning device Rosy (RObot SYstem) is used – a device for adjusting the guidance template by means of stepper motors. The template is set in place using the existing plaster model in this positioning device, in which it can be adjusted – spatially defined – by five stepper motors. Three stepper motors are located on three carriages, a further two stepper motors are at the cardan suspension.

The desired prosthetic implant position is now sought in Rosy by adjusting the stepper motors. This is indicated by a pointer located above the model (fig. 1). These stepper motors are controlled through a connected tablet (fig. 2). The position is stored in the tablet database (fig. 3). Now a spindle is connected to the upper carriage of the positioning device. In this spindle a drill bit is clamped, the diameter of which is chosen such that a hole drilled into the template can take a titanium sleeve (fig. 4). This sleeve is easily recognizable in the radiograph (fig. 5).

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