What is one advantage of an automatrix over a universal matrix

When starting your first job at a new practice, there are so many things to learn and to get used to. The materials and equipment at your practice may be different to what you had at university, but this doesn’t mean you cant produce great work with them. One of your every day, bread and butter pieces of equipment that could have you stumped is the matrix system.

Myself and David trained at USyd using primarily the tofflemire. We also had access to Triodent’s V3 and Palodent’s BiTine sectional matrix systems – but that was it! On my first day in practice there was of course the old faithful tofflemire, but the only sectional matrix was the V-ring by Triodent (essentially V1, not V3). Using it was a struggle, but I wasn’t the only one having issues. Many of my colleagues were in the same boat, working with unfamiliar equipment.

Below is a summary of some of the more common matrix systems which you may need to become comfortable with when starting at a new practice:

V3 ring by Triodent

Components

• V3 ring x2 – Green (Universal) and Yellow (Narrow)
• Tab matrix – 3.5mm, 4.5mm, 5.5mm, 6.5mm
• Plastic wedges – White (Small), Pink (Medium), Purple (Large)
• Pin-tweezers
• Forceps

Instructions for use

1. Ensure the contact is cleared
   
2. Place the appropriate sized tab matrix inter-proximally using the pin tweezers. The highest point of the matrix should sit at the desired marginal ridge height – if it sits above or below this, choose a different tab matrix
3. While holding the tab matrix still, place the smallest wedge that fits snug in the embrasure and seals the base of the box – Check from the occlusal that the matrix adapts to the base of the box with no gaps. There is no advantage in using a larger wedge as separation is achieved through the ring, not the wedge.
4. Place the V3 ring inter-proximally with the forceps. The ring should be straddling the wedge and placed as gingival as practical. Generally speaking, use green for molars and yellow for premolars, the ring can be mesial or distal

Tips

• Generally no need for burnishing as the bands are ideally contoured
• If the matrix is too high, change it to a different size. This will save you time later as you shouldn’t need to adjust the marginal ridge height much
• If there is a gap between the tab matrix and the box, use a larger wedge or wrap some teflon tape around the wedge to seal the box. Spending time on this step prevents wasting time removing overhangs later

V-ring by Triodent

Components

• V-ring
• Tab matrix – 3.5mm, 4.5mm, 5.5mm, 6.5mm
• Plastic wedges – White (Small), Pink (Medium), Purple (Large)
• Pin-tweezers
• Forceps

Instructions for use

1. Ensure the contact is cleared
2. Place the appropriate sized tab matrix inter-proximally using the pin tweezers. The highest point of the matrix should sit at the desired marginal ridge height – if it sits above or below this, choose a different tab matrix
3. While holding the tab matrix still, place the smallest wedge that fits snug in the embrasure and seals the base of the box – Check from the occlusal that the matrix adapts to the base of the box with no gaps. There is no advantage in using a larger wedge as separation is achieved through the ring, not the wedge.
4. With a finger from your non-dominant hand firmly on end of the V-ring, place the V-ring inter-proximally with the forceps. The ring should be straddling the wedge and placed as gingival as practical.
5. After disengaging the forceps, slowly remove your finger from the ring, ensuring it is stable. If you do not do this, the ring will likely fly off of the tooth

Tips

• Be very slow and careful when disengaging the forceps after placement, keeping firm pressure with a finger on the ring. If you don’t do this, it may fly off, scaring you and your patient! This was my biggest issue with the V-ring
• Generally no need for burnishing as the bands are ideally contoured
• If the matrix is too high, change it to a different size. This will save you time later as you shouldn’t need to adjust the marginal ridge height much
• If there is a gap between the tab matrix and the box, use a larger wedge or wrap some teflon tape around the wedge to seal the box. Spending time on this step prevents wasting time removing overhangs later

BiTine by Palodent

Components

• BiTine ring
• Pre-contoured metal matrix forms – 3 sizes
• Wooden or plastic wedges
• Rubber dam forceps

Instructions for use

1. Ensure the contact is cleared
2. Place the metal matrix inter-proximally using tweezers. The shorter end of the jelly-bean-shaped matrix is placed gingivally. The highest point of the matrix should sit at or just above the desired marginal ridge height – if it sits below this, choose a larger matrix
3. While holding the matrix still, place the smallest wedge that fits snug in the embrasure and seals the base of the box – Check from the occlusal that the matrix adapts to the base of the box with no gaps. There is no advantage in using a larger wedge as separation is achieved through the ring, not the wedge.
4. Place the BiTine ring inter-proximally with the forceps. The tines of the ring should be sitting on top of the wedge.

Tips

• Burnishing of the matrix is often necessary to ensure a firm contact
• The tines of the ring may cave into the box if the preparation is very wide. If this happens, you need to remove all components of the matrix, build up the walls of the box in composite using a tofflemire or free-hand, and then replace the matrix system

Garrison Composi-Tight 3D

Components

• Composi-Tight 3D ring
• 3D fusion full curve matrices – Grey (Premolars), Orange (Deep premolars), Purple (Large premolars or small molars), Green (Molars), Dark blue (Deep molars)
• 3D fusion wedges
• Ring placement forceps

Instructions for use

1. Ensure the contact is cleared
2. Place the appropriate sized matrix inter-proximally. The highest point of the matrix should sit at the desired marginal ridge height – if it sits above or below this, choose a different tab matrix
3. While holding the tab matrix still, place the smallest wedge that fits snug in the embrasure and seals the base of the box – Check from the occlusal that the matrix adapts to the base of the box with no gaps. There is no advantage in using a larger wedge as separation is achieved through the ring, not the wedge.
4. Place the Garrison ring inter-proximally with the forceps. The ring should be straddling the wedge and placed as gingival as practical.
5. Push the metal matrix into the desired contact point of the adjacent tooth with a blunt instrument such as a ball burnisher

Tips

• Burnishing is not necessary, only a push with a burnisher to establish the point of contact

Omni-Matrix by Ultradent

Components

• Single-use Omni-Matrix retainer-matrix unit
• Wooden or plastic wedges

Instructions for use

1. Loosen the omni-matrix retainer-matrix unit and place over the tooth with the retainer against a wall of natural tooth – as is done when placing a tofflemire
2. Tighten the band with the screw piece at the end of the retainer
3. Place a wedge in the embrasure which fits with pressure, to achieve separation of the teeth
4. Burnish the matrix into the adjacent tooth to form a contact point

Tips

• The wedge must exert enough pressure on the tooth to achieve enough separation to account for the thickness of the matrix band
• Ensure the height of the wedge doesn’t encroach on the contact point. If it does, trim that part of the wedge with a high speed
• Essentially a single-use tofflemire, this will give a similar contour and contact. Best reserved as a last option if sectional matrixes are available

AutoMatrix by Dentsply

Components

• AutoMatrix bands – Medium/thin (Premolars, molars), Narrow/regular (Short premolars and molars), Medium/regular (Premolars, molars), Wide/regular (Long molars)
• Automate tightening device
• AutoMatrix snippers

Instructions for use

1. Choose the appropriate AutoMatrix band size
2. Unroll the coil of the band slightly with your fingernail so that the tightest side of the band is wide enough to fit around th
   
   e occlusal circumference of the tooth
3. While holding the band in place with firm finger pressure, tighten the AutoMatrix with the Automate Tightening Device by turning the handle clockwise until two-to-three clicks are heard.
4. Remove the tightening device by rotating handle counter-clockwise.
5. Place wedges interproximally as required and burnish contacts point/s.

Tips

• To remove the automate tightening device, turn counter-clockwise a little as you withdraw
• To remove the matrix, cut the extension off of the coil – be careful with this as it in itself is sharp, while also leaving a sharp edge on the band
• The wedge must exert enough pressure on the tooth to achieve enough separation to account for the thickness of the matrix band
• Ensure the height of the wedge doesn’t encroach on the contact point. If it does, trim that part of the wedge with a high speed
• Similar again to the contact and contour achieved with a tofflemire. Best reserved as a last option if sectional matrixes are available

Final words…

You may not be lucky enough to be given your ideal matrix from the beginning. There will always be different products and equipment used between workplaces. Its your responsibility to give your patients the very best outcome that you can achieve, and if used correctly, you can get a clinically acceptable result with any of the major matrix systems. Get familiar with your system, ask questions about its application to your seniors, and don’t be afraid to explain to them the steps you took in any of your failed cases.

Thanks to Drs Jamie Lam, Jelena Skovrlj, Lloyd Claringbould and Akshay Sidana for their input into this DHS post using their experience with the above matrix systems.