by BjÖrn Ludwig, DMD, MSD; Bettina Glasl, DMD, MSD; Thomas Lietz, DMD; and S. Jay Bowman, DMD, MSD

A preoperative diagnostic aid for miniscrews

Figure 1: A sketch of a wire guide for inserting a miniscrew.

Iatrogenic injuries to roots, sinuses, nerves, and vascular bundles are potential risks when inserting miniscrews for orthodontic applications. Consequently, it may be preferable to use radiopaque guides to assist in determining proper insertion points in order to minimize the risk of injury during placement of a miniscrew. The X-ray Pin is a simple orientation aid that can help to determine more ideal miniscrew positioning.


New techniques and devices for orthodontic treatment are constantly being introduced. There are always new trends that are regarded as “fashionable” and attract the clinician’s attention. It certainly appears that miniscrews, self-ligating brackets, and digital imaging have recently stirred the interest and imagination of today’s orthodontists. This article combines two of these topics: miniscrew anchorage and imaging processes.

The most common reasons that miniscrews have yet to reach everyday use in clinical orthodontics are the need for anesthetic and the anticipated risks associated with their surgical insertion. These risks include screw loss or breakage and damage to anatomical structures.

Figure 2A: A model with a laboratory-made radiopaque guide for inserting a miniscrew.
Figure 2B: A radiograph of the guide position.

X-ray Diagnostic Aids

Prior to placement of a miniscrew, it would be beneficial to accurately determine a “safe zone” for insertion. A number of radiographic aids have been introduced to assist with selecting proper positioning of miniscrews (Table 1). These devices may help to avoid risks and to provide a better overview of the anatomy in the selected site. The most common aid elements consist of wire segments bent into various configurations (many now available as preformed products) that are temporarily attached or “keyed” to the occlusion using stents of acrylic or silicone (Figure 1). These wire segments can also be attached to the braces or base archwire. One disadvantage of this type of direct attachment is the risk of loss or bending before or while taking a periapical radiograph. These devices also often require an impression for a study model and subsequent laboratory fabrication (Figures 2A and 2B).

Imaging Processes

3D volumetric tomography (CBCT) is a popular topic today as the availability of these machines has increased. CBCT has certainly improved the quality and safety of dental implantology; however, the cost/benefit ratio and the degree of radiation must be considered carefully before routinely recommending these images for the simple placement of the majority of miniscrews.

Figure 3: The x-ray pin has a ball-shaped head and an undercut for tying dental floss.

The panoramic radiograph has become a standard for diagnostic purposes in orthodontics. Focusing on specific locations of interest using individual periapical radiographs is also recommended when necessary. Unfortunately, all 2D images, despite the most careful technique in taking them, suffer from distortions, superimpositions of anatomical structures, or errors in interpretation. Nevertheless, these images remain the medium of choice in the field of miniscrews.

X-ray Pin

Based on a pilot and research study, new orientation aids (Figure 3) have been developed to provide as many advantages as possible for preoperative diagnosis and yet be economical to use clinically. In other words, accuracy should be maximized while reducing the cost and time commitment. This work resulted in the concept of the so-called X-ray Pin, a simple radiographic guide for everyday clinical use.

The X-ray Pin is a 3.5-mm-long, steel miniscrew analog (Figure 3). In other words, it is designed to function like a “push pin” or thumbtack to model the position of a miniscrew prior to actual insertion of the implant. The shaft of the X-ray Pin is conical and features a sharp tip to facilitate perforation of the gingiva and retention in the periosteum.

Figure 4A: The head of the X-ray Pin corresponds to the diameter of the Forestadent Ortho Easy miniscrew.
Figure 4B: Inserting the X-ray Pin through the gingiva and anchoring it temporarily in the periosteum using Weingart pliers.
Figure 5: An X-ray Pin in place prior to taking a periapical radiograph.

After a site for miniscrew insertion has been selected and the soft tissue has been anesthetized, a sterile X-ray Pin is inserted through the gingiva using a Weingart pliers with force sufficient to lodge the point just in the surface bone (Figures 4A and 4B). The device will remain in position until a diagnostic radiographic image (using proper cone paralleling techniques) can be evaluated (Figures 5 and 6).

Upon removal of the X-ray Pin, the selected insertion point will have been marked with a minute bleeding point, so that finding the exact location just prior to insertion of the miniscrew is simple. It is also critical to consider clinical examination of the site in relation to anatomical landmarks before insertion is initiated. It is important to note that the X-ray Pin provides information regarding the insertion location but does not take into account the effect of insertion angle or direction.

To guard against aspiration of the X-ray Pin, a “safety cord” is necessary. A piece of dental floss is tied around the undercut under the head of the device and the ends of the floss are then extended outside the mouth (Figures 3 and 5). The head of the X-ray Pin corresponds to the shaft diameter of the commonly used miniscrews (Figure 4A).

Using the X-ray Pin is an invasive process, so the device must be sterilized, and it is also important to adhere to appropriate hygiene guidelines. All positioning aids are intended for single use only.


At the moment, there are two diagnostic pins available: the X-ray Pin (Forestadent, Pforzheim, Germany) and the tomas®-X marker (Dentaurum, Inspringen, Germany). The head of the tomas-X marker has a flat portion that provides a surface for easy handling with a pliers during insertion. It is delivered in individual packaging, ready for sterilization, and has the convenience of having a cord already attached to safeguard against aspiration. In contrast, the X-ray Pin is delivered in packs of 20 that must be individually sterilized. Although the dental floss must be attached to the X-ray Pin, it is less expensive than the tomas-X marker (Figure 7).

Well-designed miniscrew systems are distinguished not only by the features of the implant itself, but also by a well-coordinated conceptual system ranging from the associated instruments to auxiliary devices. As such, both the Ortho Easy® (Forestadent) and the tomas® (Dentaurum) miniscrew systems feature an integrated positioning aid (Table 2).

Figure 6: A diagnostic control radiograph with an X-ray Pin in place. The anticipated position of the miniscrew relative to the adjoining teeth and also the availability of circumferential bone can be easily evaluated prior to the actual insertion of the implant.

Figure 7: The X-ray Pin is supplied in a pack of 20 units.

Diagnostic Consideration

After appropriate diagnosis and selection of a site for miniscrew insertion, the X-ray Pin is oriented in the same manner that a miniscrew will be subsequently placed. This orientation is based on radiographic and model analysis of the location to determine if there is sufficient interradicular bone to safely support the miniscrew and to rule out the possibility that any vital structures (such as vascular and nerve bundles, or maxillary sinus) will be at risk. In addition, the angulation of these devices is important to help to reduce errors in radiograph interpretation. In other words, the X-ray Pin should be placed perpendicular to the cortical bone. This is done despite the fact that the miniscrew will often be inserted at a completely different angle to maximize greater contact between the threads and the dense, cortical bone, thereby maximizing primary stability. If the X-ray Pin is not placed perpendicularly, then misinterpretation of the positioning of the pin in a periapical radiograph may result.

Figure 8A and 8B: Ortho Easy® miniscrew demonstrating adequate bone around the implant, inserted after verification of the position of the X-ray Pin in the diagnostic control radiograph.

The accuracy of any type of x-ray aid, including the X-ray Pin, is highly dependent upon the accuracy of the x-ray tube/object/film or sensor orientation. The misinterpretation of any distortion of radiographic images may lead to false positive or negative results. Therefore, when selecting the insertion position of a miniscrew, please consider the clinical examination of the site as the decisive factor and the information from any radiographic aids as secondary.

Not only does the position of the X-ray Pin relative to the roots of adjacent teeth have to be taken into account, but particular attention must also be paid to the amount of bone available along the vertical axis. This is to ensure that there is sufficient circumferential bone around the mini-screw when it is inserted (Figures 8A and 8B). Since the diameter of the head of the X-ray Pin is the same as the miniscrew, measurements of the amount of available interradicular space relative to the miniscrew are more accurate than with wire segment guides.

Conclusion and Summary

As systematized procedures are more routinely used, skeletal anchorage with mini-implants has the potential of becoming standard practice in orthodontics. In addition, the mechanical aspects are continually being simplified by the introduction of auxiliary and ancillary products (often prefabricated). The safe application of miniscrews requires careful clinical inspection and preoperative diagnostics. As a result, radiographic technique and diagnosis are critical. The X-ray Pin system provides a simple, quick, and inexpensive enhancement for site selection immediately prior to the insertion of a miniscrew.

For more information on miniscrews, please see Mini-implants in Orthodontics: Innovative Anchorage Concepts, edited by Ludwig, Baumgaertel, and Bowman, published by Quintessence.

Table 1
Table 1
Table 2
Table 2

BjÖrn Ludwig, DMD, MSD, is in private practice in Traben-Trarbach, Germany. He can be reached at

Bettina Glasl, DMD, MSD, is in private practice in Traben-Trarbach, Germany. She can be reached at

Thomas Lietz, DMD, is in private practice in Neulingen, Germany.

S. Jay Bowman, DMD, MSD, is in private practice in Portage, Mich, and is a member of Orthodontic Products’ Editorial Advisory Board. He can be reached at