Having successful endodontic treatment highly depends on understanding tooth anatomy. However, the complexity of the root canal system and morph variations of people’s teeth often make endodontic treatment challenging. This is especially true among molar teeth, as the splitting and union of root canal systems when they connect to the apex of the tooth vary. For endodontists, the technique in accessing these channels is an ever-evolving study. Among these studies, endodontists often look into the development of the MB2 canal or the second mesiobuccal canal. This canal in particular often frustrates endodontists when treating patients, often due to the difficulty in reaching the canal.
Today, we’re looking into the structure of the root canal system, diving into the importance of treating the MB2 canal, and what techniques can be used to increase the success rate of a patient’s root canal procedure.
The History and Structure of the MB2 Canal
In 1917, The discovery of the MB2 canal occurred when Dr. Walter Hess injected vulcanized rubber into the root canals of human teeth. By removing the rubber after it hardened through de-calcification, these models of root canal structures clearly showed the presence of the MB2 canal throughout the maxillary molars. However, many dental treatments for root canal pain were still considered rudimentary, and thus many dentists often went forward without treating the MB2 canal. It wasn’t until 1969 that the maxillary second molars were beginning to be defined and classified into types to allow dentists to better understand the tooth’s configurations and find the appropriate technique for treatment.
When speaking about the MB2 canal, we’re specifically referring to both the maxillary first molar and maxillary second molar. For the first molar, it is the earliest permanent tooth that appears within the oral cavity and thus makes it highly vulnerable to caries. When it comes to the MB2 canal within the maxillary first molar, its complexity and positioning within the tooth make treating the root difficult for many endodontists. The MB2 canal often occurs in between 48 to 88% of people across the world. As for the maxillary second molar, what makes the second molar unique is its high rate of root fusions, where the second molar can have between one to five roots and has a fusion rate of between 5% and 42%. However, the most common iteration of the maxillary second molar is four root canals, with the MB2 canal being one of them.
Out of the entirety of the teeth, both the maxillary first molar and maxillary second molar have a higher amount of predictability in comparison to other molars, such as the maxillary third molar and other areas of the mouth. However, because teeth are entirely unique to the individual, both of these molars will still have variations in root canal development, as noted by researchers over the course of the last 20 to 40 years.
Why Treating the MB2 Canal Matters
Among endodontists that often perform root canal procedures, many often leave the MB2 canal due to its lessened impact on the treatment itself. Many patients have often gone off with successful root canal procedures that have removed the infection and helped retain the structure of the tooth. However, for experienced endodontists constantly performing complex procedures, the MB2 canal can present a higher risk of failure due to the remaining leftovers of bacteria within the system itself. In these cases, it can turn into ongoing pain for the patient, higher sensitivity to hot and cold temperatures, and a higher chance of the tooth becoming necrotic due to a longer-lasting infection.
The main reason that endodontists often don’t treat the MB2 canal within these teeth is because of the sealing process used during treatment. The sealing process during a normal root canal procedure usually allows the bacteria within the canal to die off. However, the root canals often communicate through the form of isthmuses or anastomoses. The isthmus and anastomoses connecting the tissues, pulp, and blood vessels to each root can easily allow the bacteria to spread from one root to another and thus make reinfections more likely.
Treating the MB2 Canal
This increased chance of root canal failure leads many endodontists in this field to look at the varying effects of treating the MB2 canal. Thankfully, the development of CBCT technology has allowed many endodontists to identify endodontic issues within the maxillary molars. In these cases, treating all root canals is the best method to go by when addressing complex oral problems. For endodontists, treating the MB2 canal should go through the following steps:
- Diagnosing The Condition: Observing the state of the tooth using CBCT technology or cone-beam tomography systems can help capture data scanned, allowing endodontists to look inside the tooth to observe any abnormalities and other various conditions.
- Finding the MB2 Canal: Through observing the data presented and examination in person, endodontists should attempt to look for the MB2 canal and observe its position in relation to its other canals. By observing its condition, including where its location in relation to the grooves and fissures that form the tooth’s pulp and dentin, the MB2 canal can be diagnosed and handled during a scheduled root canal treatment.
- Treating Adjacent Canals First: When preparing and treating a tooth faced with issues such as necrotic pulp, infected pulp, or calcified root canals, addressing the MB1 canals and other located canals can help isolate the MB2 canal separately during the procedure.
- Addressing the MB2 Canal: When observing and treating the MB2 canal, the canal itself should be instrumented during sections of grooving in the proper direction of the canal system and then cleaned thoroughly when located.
Because of how small the MB2 canal is, many endodontists today often have various tips and pieces of advice for treating the canal in relation to the rest of the tooth. When observing rates of infection, decay, and failure rate of root canal procedures, it’s essential that the MB2 canal be paid more attention to when treating a patient’s teeth.
