More and more in my practice my preparations are partial coverage. Our ability to use all ceramic restorative solutions and adhesive bonding to seat have allowed this increased conservation of tooth structure. This trend has also brought with it more and more preps that lack traditional retention and resistance form. One of the inherent challenges with partial coverage preparations is temporizing and cementing these interim restorations in a way they stay put. I often joke with my patients that I expect one of two things from their professionals, they will either come loose all the time and drive us both crazy, or they will have to be cut off the day we have them back to get the final restoration.
In two previous posts I discussed a patient I suspected of having a restricted envelope of function due to his symptoms and repeatedly breaking his provisonals. At the last appointment when we remade the anterior provisonals we also captured full arch impressions a facebow and a protrusive record so I could mount the case and work out a new occlusal scheme. My goal on the mounted models is to increase his freedom in the anterior. There are two ways to approach this, decrease overbite and increase overjet. Decreasing overbite is also an esthetic decision. In this case we already had minimal tooth display at rest so shortening the upper anterior teeth to decrease the overbite was out of the question. That leaves me with the options of shortening lower anteriors. We definitely had room to level the lower anteriors and shorten them a small amount.
With the increase n the amount of bonding procedures that we do everyday, tissue health has become an even more important conversation. There is nothing more disheartening than removing provisionals to seat the final restorations and looking at red, puffy inflamed gingival tissues. The tissue health is a critical factor to successful bonding and cementation. There are many factors that contribute to the gingival health at the seat appointment. One is the patients oral hygiene. Having myself had splinted provisionals I am clear that very few of my patients are going to use floss threaders. At best we can hope for patients brushing and even then if they are worried about knocking off their temps they will be skiddish about their oral hygiene.
Anterior provisionals are an important way to differentiate your practice. Patients, their friends and family and specialists are amazed by exquisite provisionals and it clearly demonstrates your offices commitment to excellence. One of the key ingredients is the shade, matching value, chroma and hue whether we are doing a single tooth or a full arch. All of our provisional materials are monochromatic and can appear lifeless even when polished. With the simple step of custom staining we can add life, vibrancy and depth to the provisional.
In a prior post I mentioned that the incidence of pulpal death following an indirect restorative procedure is approximately 13%. This number goes up to near 18% if the same tooth also had a buildup done as part of the process. The research is clear that the largest insult to the pulpal tissue is bacteria. Whether from caries, introduced into the tubules during preparation, or present from a leaking temporary restoration. Well fitting provisional margins are our best defense against leakage.
Copyplast is a popular material for fabricating a provisional matrix. The material comes in multiple thicknesses from Great Lakes Orthodontics and is available for both the Biostar/Ministar and a vacuum form machine. The unique surface of copyplast captures the detail off a model of a wax-up for provisionals, but does not stick tot he bisacryl. It can be removed during the initial set phase of the Bisacryl, or allowed to reach a firm set if you are following a shrink wrap Technique. Unlike Biocryl, Copyplast is bendable so it can beflexed buccal and lingual and removed from the provisional easily.
To continue our conversation about provisionals let’s discuss interproximal contacts. It is critical to create a contact between the provisional and the adjacent natural teeth to prevent the prepared tooth from drifting. Drifting results in an open contact or an overly tight contact, both if which are challenging to solve chair-side. One of the challenges is to create a tight interproximal contact and the proper size and shape of the contact surface to prevent food impaction and allow for gingival health.
This week I am recording a webinar for Dental XP entitled “Provisionals As A Key To Practice Referrals”. Putting together the presentation I came across a photo that I haven’t used in years when teaching about provisionals, and it speaks to the need for marginal integrity. It can be easy to get drawn into a certain cavalier attitude about provisionals since they stay in the mouth a relatively short time. What we have to keep top of mind is the importance that few weeks means to the success of the final restoration, the health of the tooth and our good will with the patient.
I am a strong believer in patient approved provisionals in cases where we are making esthetic changes to anterior teeth. I have patients back a week or two after placing anterior provisionals. This appointment is designed to review the appearance and get the patients approval prior to sending the case to the lab for fabrication of the final restorations. Additionally we test the phonetics and function. If everything is a go we photograph the patient and take a model of the approved provisionals to send to the technician.
The last two posts have focused on utilizing shell provisionals during the restoration of an entire arch of teeth. A critical step in the fabrication of any provisional is trimming to perfect the marginal fit and create the proper embrasure form and emergence profiles. Once the provisional has been trimmed the final polish not only creates the esthetics but a smooth surface that optimizes tissue health. For many years I trimmed my provisionals with carbide burs in a straight handpiece.