Incidence and Risk Factors of Bioceramic Sealer Overfilling in Single-Cone Root Canal Treatment of Teeth with Apical Periodontitis: A Retrospective Study
This retrospective study of 1,963 teeth with apical periodontitis found that bioceramic sealer overfilling during single-cone root canal treatment occurs in nearly half of cases and is significantly driven by operator inexperience, molar location, tooth mobility, and severe preoperative periapical destruction.
Original paper licensed under CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). This is an AI-generated explanation of the paper below. It is not written or endorsed by the authors. For technical accuracy, refer to the original paper. Read full disclaimer
Imagine your teeth are like ancient castles, with deep, winding tunnels (root canals) running down to their foundations. Sometimes, the "guards" at the very bottom of these tunnels—the nerves and tissues—get sick and inflamed, a condition dentists call apical periodontitis. To save the castle, dentists perform a rescue mission called a root canal treatment. They clean out the infection and then seal the tunnels shut to keep new invaders out. For decades, they used a thick, putty-like glue (traditional sealers) to do this. But recently, a new, super-smooth, self-hardening "magic gel" called bioceramic sealer (specifically a brand named iRoot SP) has become popular. It's like a high-tech, self-leveling concrete that flows easily into every tiny crack.
However, there's a catch. Because this magic gel is so runny and flows so well, it's a bit like trying to fill a leaky bucket with a garden hose: if you aren't careful, the gel might squirt right past the bottom of the tunnel and spill out into the surrounding soil (the jawbone). While this new material is generally friendly to the body, spilling it out isn't ideal; it can cause temporary pain or, in rare cases, irritate nearby nerves or sinuses. So, the big question for dentists is: "When does this magic gel accidentally spill out, and who is most likely to make that mistake?" Understanding this helps dentists know when to be extra careful, ensuring the castle stays safe without causing a mess in the neighborhood.
This study acts like a giant detective report, looking back at nearly 2,000 root canal treatments performed on teeth with infections. The researchers wanted to find out exactly how often this "magic gel" (iRoot SP) spilled out when used with a specific method called the "single-cone technique" (which is like using one main plug and relying on the gel to fill the gaps). They found that the gel spilled out in almost half of the cases—specifically, 49.3% of the time. That's a lot! But the real story isn't just the number; it's why it happened.
The investigation revealed four main "villains" that made the spill more likely. First, it was all about the experience of the dentist. Dentists who had been practicing for five years or less were significantly more likely to have the gel spill out compared to their more seasoned colleagues. It's like a novice driver being more likely to overshoot a tight parking spot than a pro. Second, the type of tooth mattered a lot. Molars (the big grinding teeth in the back) were much more prone to spilling than front teeth or premolars. This makes sense because molars are like complex labyrinths with multiple tunnels, making it harder to control the flow.
Third, the stability of the tooth played a role. If a tooth was already a little wobbly (Grade I mobility), the gel was more likely to escape. Finally, and perhaps most importantly, the severity of the infection before the treatment started was a huge factor. The researchers used a scoring system called the Periapical Index (PAI) to measure how much bone damage was already there. The worse the damage (a higher PAI score), the more likely the gel was to spill out. It's like trying to plug a hole in a dam that has already crumbled away; without a solid wall to stop it, the water (or gel) just rushes through.
Interestingly, the study ruled out some things people might guess are important. The patient's age, their gender, whether they were in pain when they walked in, or whether it was a first-time treatment or a redo didn't seem to change the odds of a spill. Also, for the front teeth, the specific size of the tools used to clean the tunnel didn't seem to matter as much as the other factors.
The researchers used advanced math to confirm that these four factors—dentist experience, tooth type, tooth wobble, and infection severity—were the true independent causes, not just random luck. They found that the combination of a less experienced dentist, a molar tooth, a wobbly tooth, and a severe infection created the perfect storm for the gel to spill. The study suggests that dentists should be extra cautious with these specific high-risk scenarios. They might need to use less pressure or stop the injection earlier to prevent the spill. While the study didn't track what happened years later to see if these spills caused long-term problems, it clearly shows that knowing these risks helps dentists make smarter, safer choices right now to keep the "magic gel" exactly where it belongs: inside the tooth.
Drowning in papers in your field?
Get daily digests of the most novel papers matching your research keywords — with technical summaries, in your language.