Provisionals: Fit, Form & Function

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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.

Temporary Cement After Eight Weeks-Courtesy of Dr. Sorenson

Marginal integrity is important for numerous reasons. The basic premise is to prevent leakage of fluid from the mouth underneath the provisional. With leakage comes the presence of bacteria between the temporary material and the prepared surface of the tooth. We are clear that bacteria is the key contributing factor to teeth needing post-restorative endodontic treatment. The fluid movement and the bacterial infiltration of the dentinal tubules are also largely responsible for patient sensitivity. Lastly, fluid under the provisional degrades the temporary cement and eventually the temporary comes loose necessitating an emergency visit. Taking the time to ensure sealed margins minimizes the risk of pulpal death and patient dissatisfaction due to sensitivity or inconvenience.

Evidence of Leakage After Removal

Take a moment when you remove a provisional crown to visually assess where leakage was occurring, if any. The temporary cement or the tooth will be discolored and the cement will be gooey and soft. Another great way to get better when fabricating provisionals is to clean the cement out of them and seat them on the die from the lab used to make the final restoration. I look at how I did sealing the margins and creating tight contacts. The only way we get better is to measure our performance. When fabricating a provisional I find that most of the time my margins are not sealed perfectly once I get done trimming and shaping. I air abrade the internal surface of the margin and paint it with a layer of dentin adhesive. I run a bead of flowable resin on the tooth all around the margin, seat the provisional and cure. This added layer will need some additional trimming but will be far more accurate than the original bisacryl. I also find that marking the margin with a well sharpened lead pencil and trimming under magnification make an enormous difference. I recently put a pair of 2 power loupes int he lab at the office for our assistant team to use when making provisionals.