Rubber Dam for Bonding Laminate Veneers: Mandatory or Optional?
In endodontics, placing a rubber dam is an accepted principle. Over the past few years the habit has reached esthetic treatment as well, and some colleagues consider bonding a laminate veneer acceptable only under a rubber dam, while many experienced clinicians in this field have worked for years without one and have had good long-term results. The question is whether we have any evidence that rubber dam changes the lifespan of a laminate veneer.
The best starting point for a question like this is a Cochrane review. Cochrane is an international non-profit organization that, for any treatment question, collects every available trial by a strict method, weighs their quality, and states how much the result can be trusted, which is why its reviews are usually counted as the highest level of evidence. Their 2021 review asked precisely whether rubber dam, compared with cotton rolls and suction, increases restoration survival, and it was meant to cover veneers and other indirect restorations too.
The result was that for indirect restorations not a single eligible trial existed. This does not mean nobody has written about rubber dam and laminate veneers. There are plenty of papers, but almost all of them are either case reports or technique descriptions, and in those the rubber dam is merely part of the author's protocol, not something whose effect was measured.
A Cochrane review accepts only a study that randomly divided patients into a rubber dam group and a no rubber dam group and followed them. The six trials that were found were all about direct restorations and were of low quality. In cervical restorations, rubber dam may raise survival in the first six months from roughly 8 sound restorations in every 10 to 9, but this effect comes mainly from one weak study, and in the best trial in that same review no difference was seen up to 18 months.
Three practical points sit in the text of that same paper. The rubber dam recommendation in endodontics is for safety and infection control, not for bonding, so the endodontic requirement does not transfer to adhesive treatment. At the same time the authors do not regard the rubber dam as unimportant, because it prevents swallowing and protects the soft tissue, and they do not consider abandoning it entirely acceptable. And in the list of clamp complications, chipping of the thin cervical margin of a veneer is mentioned, which means that in a laminate veneer the position of the clamp and the way it is placed matter.
When we have no trials, we have to look at what decided failure in the long-term laminate veneer survival studies. Gresnigt and co-workers bonded close to 400 laminate veneers under a rubber dam and the 11-year survival was about 95 percent. Gurel and co-workers followed close to 600 laminate veneers for up to 12 years and did not report the type of isolation at all, but where the preparation had stayed entirely in enamel, survival reached 99 percent and neither debonding nor microleakage was seen. In both studies the debondings happened on dentin. A dentin margin in Gurel's work raised the risk of failure about tenfold, and in Gresnigt's work, when more than half of the prepared surface was dentin, immediate dentin sealing (IDS) clearly improved survival. In other words, what decided the fate of the laminate veneer was the substrate, not the isolation method.
The only study our search found that actually measured rubber dam as a variable in an indirect bonded restoration is the work of Vosmeijer and co-workers on more than 600 posterior ceramic inlays and onlays. Rubber dam had no significant effect on survival, and the factors that mattered were the patient's caries risk and a deep margin close to the bone. The group without rubber dam was small, however, and included only cases where placing a rubber dam was not possible, so this finding neither refutes nor confirms an effect of rubber dam.
On whether IDS itself requires a rubber dam, we found no comparative study. The closest data is the work of Saraiva and co-workers, who bonded to dentin fragments in the mouth of a volunteer using cotton rolls only. The relative humidity in the anterior region was about 85 percent, and even so the immediate bond strength to dentin did not differ from the bond strength under room conditions. In the opposite direction, another intraoral study found the bond to enamel to be stronger under a rubber dam (Falacho 2022, abstract). Both measured short-term bond strength only, and without a rubber dam the risk of direct contamination by saliva, blood and gingival crevicular fluid remains where it was.
What remains from this evidence for clinical work:
- 1. The most important decision is made before the bonding appointment. Keep the preparation, and especially the margin, in enamel, because no isolation method compensates for a weak bond to dentin.
- 2. If dentin is widely exposed, perform IDS. It is the only adhesive intervention that has improved survival in a long-term laminate veneer study.
- 3. In the laminate veneer studies, going subgingival was not shown in itself to be a cause of failure. But it becomes a problem if it drives the margin off enamel onto dentin or makes moisture control harder, and these two usually happen together.
- 4. Choose the rubber dam according to the situation. When dentin is exposed, the margin has gone subgingival, or control of saliva and gingival crevicular fluid is difficult, the case for using it is strong. With an enamel preparation and a supragingival margin, a careful relative isolation is also defensible. If you do place a rubber dam, watch the contact between the clamp and the thin cervical margin.
In short, the current evidence supports neither that rubber dam is mandatory for laminate veneers nor that it is useless.