These guidelines assume that you have received your Intro-Pack and are ready to learn how to use both the Tri-Wedge and the Tri-Clip on the tooth model that is included. Although the Tri-Clip and Tri-Wedge might look straightforward, you can save time and look more professional by learning how to use them on the model.

Download a printable PDF file of these Guidelines

If you already are familiar with sectional matrix systems then you will appreciate the significance of the Tri-Clip, which allows you to place the matrix, wedge and retainer spring in one action. Follow these instructions for guidance in how to use the Tri-Wedge and the Tri-Clip. If you are not familiar with sectional matrices, or are hesitant to try them because their use is not part of any formal teaching program, then follow these step-by-step instructions to grow your knowledge base and achieve tight contacts when performing class II restorations the easy way.

Placing a Tri-Wedge or Double-Wedge

Please note that the Tri-Wedge was developed first and the the Double-Wedge followed.  Instructions are very similar. Please inter-change the words Tri-Wedge and Double-Wedge.

Experiment first with the Tri-Wedge on the tooth model, then move on to experimenting with the Tri-Clip. Although the Tri-Wedge is an essential part in the Tri-Clip sectional matrix system, it also works really well with most other matrix band systems. The Tri-Wedge's unique "pull" design differs significantly from all other wedges that are "pushed" into the inter-proximal space.

Multiple uses for Tri-Wedges can be found here.

Placement of Tri-Wedge

Before starting take a Tri-Wedge and try pulling it. They are made of a surprisingly strong and elastic material. Most people cannot break them by pulling at either end! This motion picture shows just how stretchy they are. Step 1 Stretch the Tri-Wedge and "floss" the flat central part of the Tri-Wedge into the inter-proximal space. You can either stretch the Tri-Wedge between your fingers, or for use in posterior teeth you may need tweezers.

Step 2
Release the wedged end of the Tri-Wedge.

Step 3
Pull the thin end through until the Tri-Wedge fits tightly into the inter-proximal space (you will need to really pull to get the wedge far enough into the inter-proximal space - it is surprisingly strong and elastic).

Removal of the Tri-Wedge
While still holding the end, it is sometimes easier and quicker to cut the bobble off.
Alternatively, you can remove the Tri-Wedge at the end of the procedure by pulling the thin end and then getting your assistant to cut the end off with scissors. Then remove the wedged end. It is not always necessary to cut the bobble off prior to removing the Tri-Wedge.

Placement of Tri-Clip

We suggest that you first practise placing and removing the Tri-Clip several times on the enclosed tooth model. Start by performing a simple procedure (such as a single bicuspid class II cavity) on the tooth model, ideally following this tutorial, until you feel more comfortable with the Tri-Clip. Then you can move on to two adjacent class II cavities on the tooth model. By this time you will have developed the skills to use the Tri-Clip in a surgery environment with ease, speed and confidence. Look upon the tooth model as your dummy patient!

The Components
Each Tri-Clip is made up from a plastic retainer spring with two anatomically shaped tines, a stainless steel matrix band and an elastic wedge (Tri-Wedge). The Tri-Wedge is cleated onto the retainer spring cleats. Tri-Clips are available with the matrix facing inwards towards the spring or outwards. Contoured Mylar polyester matrices will be available soon.

The Placement Technique

Step 1

In very simple terms, when we place a matrix we are creating a tooth-shaped mould for the composite to be place into. We can either create this mould in the mouth step-by-step using our expensive and valuable labour, or we can use cheaper factory labour to make it outside the mouth. This is why the Tri-Clip makes economic sense.

In time you can learn how to place a Tri-Clip in about 10 second.

1) Following on from the above, it is vital to train your chair-side assistant (CSA) to set up the Tri-Clip ready for immediate use. She should pass you the Tri-Clip on the forceps in the correct orientation, centred and expanded with the forceps locked. Some chair-side assistants prepare the Tri-Clip while the dentist is administering the local anaesthetic and have it ready and waiting.

2) Your CSA needs clear instructions so she can understand how you want the Tri-Clip set up. Some Tri-Clips have the matrix facing Inwards to the spring and some it faces Outwards. Tri-Clips can be placed both 'forwards' and 'backwards' on the forceps.

This means you have to decide from theseTWO choices:

For MO cavities, either a) Outward forwards, or b) Inwards backwards

For DO cavities either a) Inward forwards, or b) Outward backwards

(Some people call them ‘innies’ and ‘outies’). How to decide? Is the spring goings to get in the way of oral structures such as the retro-molar area or the lower incisors? Generally you have better visibility with the spring points distally. Also consider the best angle of the matrix in relation to the embrasure to avoid the matrix catching on the gingival floor of the box.

3) Case Selection:
It is wise to select an easy case to begin with. For example a lower molar with a wide DO cavity. This is an ideal restoration for a Tri-Clip as there is good visibility (without a mouth-mirror) and a wide embrasure that allows an unrestricted passage through the contact area.

4) Bevelling:
It is now generally accepted that bevelling margins improves the marginal seal of composite restorations (click here for some references). Recently, bevelling of the gingival margin has also been recommended by some authorities. This as the advantage of obtaining a much better seal at the most vunerable margin where secondary caries is is most likely to occur. Here are some clinical examples:

Not only does this provide an excellent marginal seal, it also facilitates the easy placement of the Tri-Clip and the gingival ledge that can catch the matrix is removed. This bevel can be created with a Two-Striper 290.2M "Special Bevel" or 292.3VF or other American football-shaped bur.

Lastly, rubber-dam forceps are unsuitable as they usually do not hold the Tri-Clip firmly. When a little preparation is done beforehand, you will find that the Tri-Clip often goes on very quickly. Please print this out for your CSA to read.

Practicing on The Tooth Model

Step 1
Ensure that you have the correct type of forceps. The image on the right shows the preferred type of forceps that lock into the nodules on the springs.

 

Most rubber dam forceps are not suitable for placing the Tri-Clip. We recommend using matrix forceps with straight edge callipers. Round edged callipers are not suitable. Suitable forceps specifically designed for the Tri-Clip will soon be available from Tri-Dent. When available they can be ordered online from the website www.TrioDent.com. Click on the Ordering Online link, or order by fax online by clicking on the Fax Ordering link, or telephone 1-800-811-3949.
We strongly recommend that you train your chair-side assistant to pass you the Tri-Clip on the forceps in the correct orientation, expanded, centered and locked- all ready to go - as this will save you even more time. Take time to explain the next part carefully to your assistant. Select an inward Tri-Clip and with the wedge pointing upwards, expand the plastic retainer spring by placing the callipers of the ring forceps between the tines and the nodules on the inner circumference of the spring. Expand the plastic retainer spring wider that you might expect so that the matrix wings are almost (but not!) coming out of their slots.
A good way to achieve this is to press lightly against both wings of the matrix with a finger or thumb while opening the forceps. You can see this in the picture to the right. This allows the Tri-Clip to easily go through the contact without being impeded by the teeth. Check that the matrix is centred. Lock the forceps.

Step 2
In the picture to the right, position the Tri-Clip with the matrix band and wedge above the inter-proximal space of choice on the tooth model, guide the matrix into position in the inter-proximal space. Release the forceps lock, release the forceps while ensuring the tines of the Tri-Clip grip the undercuts on the buccal and lingual surfaces of the teeth.

Step 3
Uncleat the wedged end of the Tri-Wedge with tweezers first, then uncleat the thin end. Then without letting go, pull the thin end while supporting the Tri-Clip. You can pull the Tri-Wedge in any direction that is convenient so long as you hold the Tri-Clip in place while pulling.
It is also a good idea to train your chair-side assistant to have the scissors ready and cut off the bobble on the thin end while you are still pulling on it. Alternatively, you can do this step later when you are removing the Tri-Clip.

Removal Technique
Step 4
The Tri-Clip is removed while leaving the matrix in place. Place the callipers of the ring forceps between the tines and nodules on the inner circumference of the plastic retainer spring. Expand the plastic retainer spring to clear the bulbosities of the teeth. The forceps and the Tri-Clip are moved along the occlusal plane in the same direction as the wings of the matrix.

Step 5
On the model and in the mouth, remove the Tri-Clip-Wedge by cutting with scissors as outlined earlier.

Step 6
Remove the matrix with hemostat or diamond-coated Tweezers.
Take great care not to cut the gingival tissues with the wings of matrix.
[On the tooth model, since you have not placed a restoration, it is possible to lift the Tri-Clip vertically so that the matrix is still attached to the Tri-Clip. You need to loosen the Tri-Wedge before doing this. This will allow you to re-use the same Tri-Clip several times for practise purposes before moving on to the correct removal technique just described. NOTE: The SLIDING method described above in Step 4 is recommended when you have placed a restoration].

Completing a Restoration on the tooth model
Now try an actual restoration on the tooth model. If you are already familiar with sectional matrix systems, compare the Tri-Clip with your system of choice to appreciate the difference. It is more difficult to use other sectional matrices in a surgery environment, the difference in a real time application between the Tri-Clip and other sectional matrices will become even more apparent.

Step 7
Select a class II cavity in the bicuspid area of the tooth model. Place the Tri-Clip as described in the first familiarisation routine described above.

Step 8
Uncleat the Tri-Wedge as already described and engage the wedge until the matrix is in close contact with the gingival margin of the cavity. Burnishing of the matrix may also be desirable to establish a good contact form. You may need to use a hand-instrument to hold the matrix against the adjacent tooth. Restore the tooth in your usual manner.

Step 9
The Tri-Clip works with any kind of dental restorative material, your restorative technique is a matter of professional choice.

Step 10
Remove the Tri-Clip and the Tri-Wedge as already described.

Step 11
Remove the matrix with hemostat or diamond coated tweezers. If a bonding agent was applied to the matrix, use a straight explorer instrument inter-proximally between the matrix and the restoration to separate. Finish the restoration. It is advisable to "post-cure" light cured restorative materials following matrix removal from all surfaces, including proximo-facial and lingual line angles.

Restoring Two Adjacent Proximal Cavities
One the cleverest uses of the Tri-Clip system is in restoring two adjacent proximal cavities. You can practice this on the tooth model. The technique is shown here.

In the Dental Office

In the dental office, it will pay to select a simple procedure for first real-time use of the Tri-Clip. We recommend that you start with classical GV Black's cavity in a bicuspid. See the clinical example of a DO restoration on a bicuspid on the right. Then move on to using Tri-Clips in lower molars, followed by upper molars. A dental mirror is often required in upper molars and this makes placement a little harder.

Remember that Tri-Clips can be used in more situations than other sectional matrices, particularly on wide cavities and sometimes when otherwise you might use a matrix band.

What if the Contact is Tight (less than 0.3mm)?
If the contact is tight, either
a) remove the Tri-Wedge, (because wedging is not necessary) or
b) flare out and bevel the margins to open out the contact point. Bevelling axial walls may remove a few milligrams of enamel (sacrilege!) but it does enable you to bond to the ends of enamel prisms instead of trying to bond to the sides of the prisms (which is impossible). [On this issue, I believe that you either lose the few milligrams of beveled marginal enamel and get a good seal and a long-lasting restoration OR you lose those milligrams (and more) with secondary caries.]

Here is quote from Liebenberg "This author subscribes to the notion that bevels provide more exposed enamel rod ends for bonding and should be utilized when sufficient residual enamel height (> 1 mm) is present. Using the acid-etch technique, the resin-enamel bond is stronger with etched transverse sections of enamel prisms than with longitudinal sections. Research has indicated that bevels reduced microleakage at the cervical and ascending walls of Class II composite resin restorations. Consequently, enamel in the proximal and gingival wall of Class II cavity preparations should be beveled since prism direction is at right angles to the surface."

Here is Liebenberg's cavity prep.

Other Information
Click on Clinical Examples and Hints and Tips for more advanced techniques, or click on Frequently Asked Questions for queries you may still have about the Tri-Clip or the Tri-Wedge. If you need further help click on Contact Us for contact details and how to send us an email.