Mineral trioxide aggregate (MTA) fails less often when used for direct pulp capping than calcium hydroxide (CaOH), a new study shows.
In a large, randomized controlled trial by Thomas Hilton, DMD, a professor of operative dentistry at Oregon Health Sciences University in Portland, and colleagues, 24.6% of pulp caps made with CaOH failed within 2 years compared with only 13.6% of those made with MTA.best cosmetic dentist london
The study was published online May 20 and in a clinical supplement to the Journal of Dental Research.
Dentists using CaOH for direct pulp capping should consider switching, said Dr. Thomas.
“I think that probably there is enough evidence, and I don’t just say that because of our study,” he told Medscape Medical News. “Other studies have shown the same thing. But I think our study confirms that MTA is probably better.”
Pulp capping becomes necessary when pulp becomes exposed, most often because a tooth is so decayed that the dentin covering the pulp cannot be preserved. Restorative materials cannot be placed directly against the pulp without harming it, but for more than a century, dentists have placed CaOH over the pulp, stimulating scar tissue to form a dentin bridge. In addition, CaOH has some antimicrobial properties, and a restoration can be safely placed over the CaOH as soon as it sets. Eventually, however, the pulp in many such teeth becomes infected and requires root canal therapy or extraction.
More recently, researchers have suggested MTA as a superior material for pulp capping. It seals to the tooth structure, allowing less leakage and reducing the risk for infiltration by bacteria into the tooth. In addition, MTA appears to be more stable over time.
MTA is composed of calcium oxide in the form of tricalcium silicate, dicalcium silicate, tricalcium aluminate, and bismuth oxide for radiopacity. It forms CaOH when it reacts with water, achieving similar antimicrobial effects and stimulating pulpal repair.
To compare the efficacy of the 2 materials, Dr. Hilton and colleagues used a new approach to dental research: Rather than randomly assigning patients within an academic clinic to have their pulps capped with one material or the other, they assigned working dental practices to one material or the other. The practices had agreed in advance to participate in research by taking part in the Northwest Practice-based Research Collaborative in Evidence-based Dentistry.
affordable cosmetic dentistry london By using actual dental practices, the researchers could compare the materials under the clinical conditions they are most often used. “We think we’re getting more realistic data,” said Dr. Hilton.
The practice-based network also provided more patients than the researchers could have easily assembled for a university-based trial.
A possible drawback to the approach is that the 2 materials were placed by different dentists. It would have been possible to randomly assign patients to one material or the other within each practice, but it would have been difficult for each dentist to become equally proficient in both materials, said Dr. Hilton. In addition, some research has shown that a delay in capping pulp can increase the risk for failure. Stopping to figure out which patient should receive which material could have caused such a delay, Dr. Hilton explained.
In the end, 16 practices used CaOH in 181 patients, and 19 used MTA in 195 patients. The researchers followed-up the patients for 2 years or until the tooth required extraction or root canal therapy. The median CaOH follow-up was 12.1 months (range, 0.2 – 30.9 months), and the median MTA follow-up was 15.6 months (range, 0.2 – 33.5 months).root canal treatment london
During that time, 7 CaOH pulp-capped teeth were recommended for extraction and 38 for root canal therapy. In contrast, 6 MTA pulp-capped teeth were recommended for extraction and 19 for root canal therapy.
Using Kaplan-Meier estimates, a statistical method that takes into account such factors as patients leaving the trial before follow-up, the researchers found a failure rate of 31.5% for CaOH vs a failure rate of 19.7% for MTA, a statistically significant difference (P = .046).
In a secondary analysis, the researchers found 3 additional radiographic pulp-cap failures in the MTA group, which resulted in a failure rate of 22.4% for that group and a loss of statistical significance (P = .067).