CTZ paste matched zinc oxide-eugenol pulpectomy in primary molars at 24 months
A multicentre randomized trial in Brazil found that chloramphenicol, tetracycline, zinc oxide-eugenol paste used for lesion sterilisation and tissue repair was non-inferior to conventional zinc oxide-eugenol pulpectomy in primary molars after 24 months of follow-up. The finding matters because primary tooth therapy has to balance infection control, procedure length, child cooperation, and the practical limits of treating young patients in routine dental settings.
The cohort included 199 primary molars in children aged 3 to 9 years. Investigators compared two endodontic approaches for teeth with disease severe enough to justify pulpectomy-level management, then followed the treated teeth for two years. The primary endpoint was combined clinical and radiographic success at 24 months, assessed under an intention-to-treat framework. A prespecified non-inferiority margin of 15% set the bar for whether the less conventional approach could be considered acceptably close to the standard comparator.
Success rates favored the CTZ arm numerically. In the intention-to-treat population, overall success reached 64.3% with CTZ and 58.7% with ZOE, a difference of 5.6 percentage points with a 95% confidence interval from -9.3 to 20.4. The interval stayed within the prespecified non-inferiority boundary, and the trial’s statistical analysis supported the conclusion that CTZ did not underperform zinc oxide-eugenol pulpectomy by a clinically unacceptable amount.
Chair time fell sharply without a penalty in child comfort
The procedural burden was very different between the two strategies. Mean clinical time was 36.3 minutes in the CTZ group and 63.0 minutes in the ZOE group, a substantial gap that would be difficult to ignore in a pediatric practice where cooperation can deteriorate quickly as an appointment lengthens.
This time saving is not trivial. In primary molar treatment, shorter appointments can reduce fatigue, simplify behavior management, and lower the chance that a child needs repeated stabilization or an interrupted procedure. The biologic logic also fits the technique: CTZ-based lesion sterilisation is designed to place an antimicrobial mixture into the diseased tooth rather than completing the more labor-intensive mechanical and obturative steps associated with standard pulpectomy.
Children’s behaviour, immediate discomfort, and postoperative pain did not differ meaningfully between study arms. Those outcomes suggest that the shorter CTZ procedure did not trade speed for a worse bedside experience, at least in the measures captured by this trial. For families and clinicians, that combination is especially relevant in pediatric dentistry, where the emotional and sensory burden of treatment can be as important as the technical success of the restoration itself.
One sentence captures the operational advantage: the CTZ arm finished sooner, and the pain profile did not worsen.
Why antimicrobial paste may work in a primary tooth
CTZ paste combines chloramphenicol, tetracycline, and zinc oxide-eugenol, aiming to suppress the microbial load inside the infected tooth while supporting tissue repair. In primary molars, where anatomy, root resorption, and the life span of the tooth all shape treatment goals, the target is not the same as a permanent tooth. The objective is to hold the tooth in function and avoid pain, swelling, and radiographic deterioration until exfoliation occurs naturally.
That biologic framework helps explain why a less elaborate procedure can remain competitive over two years. If microbial control is sufficient and the sealing environment is stable, the tooth may stay clinically acceptable even without the full workflow of conventional pulpectomy. The tradeoff is not academic; it is a question of whether a simpler intervention can reliably contain disease long enough for the child to outgrow the tooth.
Still, the success rates leave room for caution. A 60%-plus success rate means a substantial minority of treated teeth did not meet the combined clinical and radiographic success definition by 24 months. The study demonstrates non-inferiority, not perfection, and that distinction matters when clinicians are deciding which teeth are best suited for one technique over another.
Trial design and follow-up strengthen the clinical signal
This was a multicentre non-inferiority randomized clinical trial, which gives the result more weight than a small single-site report would. The trial was conducted across academic dental settings in Brazil, and the protocol underwent local ethical review at the participating centres. The study was also prospectively registered at ClinicalTrials.gov, and the data repository, analysis code, and full statistical report were made publicly available through the University of Sao Paulo.
The statistical approach used the Miettinen-Nurminen method to compare success proportions under the intention-to-treat principle. That matters because non-inferiority analyses are especially vulnerable to overinterpretation if missing data or protocol deviations are handled loosely. By keeping the main comparison anchored to the randomized population, the trial preserved the design needed to test whether CTZ could stay within the acceptable margin.
The confidence interval deserves close attention. Even though the point estimate favored CTZ, the upper bound extended above the zero line, meaning the data do not prove superiority. The result instead supports the narrower claim that CTZ performs sufficiently close to ZOE pulpectomy over two years while requiring less clinical time.
A second one-sentence reality check is hard to avoid: the faster method did not erase the failure rate.
What pediatric dentists can take from the 24-month comparison
For pediatric dentistry, the practical implication is straightforward. In primary molars requiring endodontic treatment, CTZ-based lesion sterilisation may offer a shorter appointment without sacrificing two-year success relative to conventional ZOE pulpectomy. In settings where chair time, child cooperation, or access to dental services are limiting factors, that difference could influence treatment selection.
The study also fits a broader clinical question: how much procedural complexity is truly necessary in a tooth that is destined to exfoliate? If a shorter antimicrobial approach can preserve comfort and function through the remaining life of the primary molar, it may be particularly attractive in busy public clinics and in children who struggle with longer interventions. Yet the endpoint still includes radiographic failure, and any future use will have to weigh the convenience of the technique against the fact that not every treated tooth held up through follow-up.
Because the article is a preprint, the findings should be interpreted with that status in mind. Peer review may refine the framing, but the current data already provide a concrete answer: CTZ paste was non-inferior to ZOE pulpectomy at two years, with a marked reduction in clinical time and no clear penalty in reported pain or behavior.