Clinical Guidelines & Technical FAQ’s
A good case for the OVC includes any structurally compromised posterior tooth, in need of full occlusal coverage. Generally, any case where the McDonald Matrix Band can be retained in a stable position is suitable.
Below are resources that will help you decide if a case is suitable for the One Visit Crown (OVC):
See a PDF with examples of OVC clinical indications showing ideal OVC case examples.
To stabilise the McDonald Matrix Band during placement, you may wish to use the wooden wedge technique. To see a video of this technique – click here.
Note: If you have a plunging opposing cusp, you will need to re-contour it first.
For more visual examples of OVC clinical cases, please see our case studies.
For visual examples on prepping teeth for OVC procedures – click here for a PDF showing clinical case prep examples.
The key to prepping teeth for the OVC is to achieve enough occlusal reduction. Use the Occlusal Reduction Guide to check for adequate occlusal reduction.
Prepare the tooth with a round diamond bur of at least 1.2 mm diameter, followed by yellow strip tapered round-end diamond bur to remove sharp edges and polish the prep. Bevel the margins for better bonding, shade blending and easier matrix application.
Have questions about the removal of sound cusps and preserving tooth structure? Here is an article on compression dome theory that explains why this might produce a stronger overall restoration.
It is important to check the occlusal clearance before starting the OVC customisation. Allow at least 1 mm of clearance in the central fossa and 1.5 mm at the cusps and marginal ridges. OVC Occlusal Reduction Guides (which are the same thickness as the hard occlusal layer of the OVC) are supplied to confirm the minimum required clearance is achieved.
The Occlusal Reduction Guide can be covered on both sides with a coloured occlusal indicator spray such as Bausch Arti-Spray® to aid high spot identification. Place the sprayed Occlusal Reduction Guide over the dried prep and get the patient to gently bite. This will leave a coloured mark on the high spots that need further trimming.
Correct vertical height and positioning can be achieved through the use of the Occlusal Seating Guide, which is custom-made by our lab technician based on your patient’s tooth impression.
The best way to speed up the overall OVC procedure is to shape and carve the uncured composite rather than trimming cured composite.
In particular, it is especially worth spending a few extra moments to carve the proximal marginal ridges before curing as these are difficult to get right after the composite has cured.
To do this, we recommend the following:
After you are satisfied with the seating and occlusal position of the OVC, spot cure to stabilise the OVC, leaving the periphery uncured. To spot cure, use the spot curing tool.
After spot curing, the occlusal dimension will be fixed but the excess uncured material will extrude from the band.
We recommend clearing away as much of this excess uncured material as possible with a fine instrument such as the IPC Off Angle Short Composite Instrument from Cosmedent.
After removing the excess material, you can carve the marginal ridges then light cure while masking the buccal side with the edge of the SpotCure instrument . This leaves the buccal composite uncured so that you can shape it. Undo the band or cut off the orange toggle to gain access to the buccal surface.
You may prefer to use Dr Terry Wong’s method, uses a smoothing pad to smooth margins and reduce finishing time prior to curing.
Before polishing and finishing, please remember to fully cure the OVC from all sides.
During the final cure, be aware of the heat emitted by your curing light and cool the tooth with air/water spray if the tooth is getting hot.
Use your preferred burs, disks and polishers and then, if desired, a soft brush with polishing paste such as Cosmedent Enamelize for high shine.
Small localized dark areas on the prep, such as an amalgam tattoo or dark dentine spots, can shine through the restoration due to the high translucency of the material. To prevent this from happening, it is advisable to bond a white opaque flowable liner over the dark areas before OVC adaptation.
Remember that when you apply bonding agent to the tooth prep and air dry, it tends to splatter and coat the inside of the matrix band. It then bonds to the OVC and the band is virtually impossible to remove unless you DEBOND the band first. Debond the band by sliding a fine instrument interproximally between the band and the OVC. Approach from the buccal side. As you keep pressing the band will pop free from the lingual side of the OVC. Often you need to prise the band away both mesially and distally before it will “pop”. Once popped, it can be pulled with tweezers from the lingual side.
If the contact is nice and tight the band needs to be wiggled out. Note that “over-tight” contacts resolve themselves within 24 hours by the neighbouring teeth moving (orthodontically). Remember that we are talking about 20-50 microns of movement. We recommend that you tell the patient that you have done a really good job getting the contacts tight and ask them to floss it the following day and make an appointment if it can’t be flossed.
Inter-proximal stripping of a very tight contact with a diamond strip is difficult, probably unnecessary (see above) and you can over do it, leaving an open contact point. It is better to leave it and deal with it if the patient still has a problem a week later. (In Dr Simon McDonald’s experience, he has never had a patient complain of an over tight contact, a day or so later).
Check for occlusal contacts interference in both central occlusion and lateral excursions. It is important to check for lateral excursion contacts and remove them to preserve the integrity of the restoration and for patient comfort.
The aesthetic appeal of the OVC can be enhanced by staining with coloured resins following the manufacturer’s instructions.