Dental Post - 2
#findmb2
Hello docs! I am here with a new topic of my blog that is about MB2.
Why MB2 is getting so much of importance nowadays? There are the reasons. Start welcoming MB2 as a normal anatomy of maxillary 1st molar.
Maxillary 1st molar is the tooth with the most complex and varied root canal anatomy. Most of the time ( say almost always) this tooth has one extra mesiobuccal canal that is named as mesiobuccal-2 i.e. MB2.
Methods to explore additional canal orifices :
1. Examination of the pulp chamber floor with sharp explorer ( DG 16 ), here we can use some test like following,
• Champagne bubble test – In this test we allow sodium hypochlorite to remain in the cavity and after some time bubbles may appear at the sites of orifices that gives the hint of hidden canal.
• Ophthalmic dye ( Fluorescein sodium, Rose Bengal) – When these dyes come into contact with vital or Non-vital pulp tissue they are readily absorbed by the connective tissue elements of the pulp in the chamber. When exposed to blue light, these dyes fluoresce and that helps to locate pulp tissue.
• Red line test – In vital teeth, blood frequently emanates from an orifice, fin, or an isthmus area. Like a dye, blood serves to map and visually aid in the identification of the underlying anatomy.
• White line test - When performing ultrasonic procedures without water in necrotic teeth, dentinal dust frequently settles into any available anatomical space. This dust can form a white dot within a hidden orifice or a white line within an anatomical fin, groove, or isthmus.
3. CBCT
4. Surgical operating microscope
Where to look for MB2 ?
• Most of the time MB2 is situated 3 mm from the MB1 canal towards palatal direction, 1-2 mm mesially from MB1 canal and 2-3 mm deep apically. So you have to dig in with these approximate values and you may get MB2 canal in most of the cases.
• If the tooth is more calcified, you may need to go more deep that is 2 mm to 3 mm(or more) apically. One must groove MB2 canal towards the palatal aspect of the tooth, not in the direction of the palatal canal.
• In maxillary 2nd molars, the MB2 tends to be closer to the MB1 canal than in 1st molars.
• DENTIN SHELF – In most of patients the MB2 is typically located under the layer of dentin that sits on the pulp floor. This layer is called the dentin shelf. Removal of this dentin shelf is necessary so that our eyes can locate the hidden canal.
How clinician should be aware of MB2 canal in every case?
‘Our eyes can see what our mind knows'
• Most of the endodontic canal detection procedures have relied on the dentist’s tactile dexterity and mental image of canal system.
• A clinician must know the basics of variable anatomical structures present in different teeth. In maxillary 1st molars the percentage of presence of MB2 canal has reached to 93%.
• Modify the access preparation to a rhomboidal shape as compared to the classical triangular outline.
• Searching MB2 is not that simple. If one grooves the floor in the wrong direction i.e. too mesial or too distal one may perforate.
• MB2 can be most difficult to find and negotiate in a clinical situation as many of the times they are narrow, curved and calcified.
•Start troughing with above mentioned values. Use of ultrasonic tips or ultrasonic
scaler becomes very useful here as they are very convenient, efficient as controlled
troughing is possible and improves visualisation. Once you get the catch refine the access, make it straight. And then start negotiating the canal with no. 8 file and then continue with 10 , 15 and 20 number K file respectively. 4% preparation is sufficient for MB2 canal.
• To categorise the canal system in each root, Weine described four different types of configurations as follows :1. Single canal from the pulp chamber to the apex
2. Two canals leaving the chamber but merging short of the apex to form a single canal
3. Two separate canals leaving the chamber and exiting the root in separate foramina
4. One canal leaving the chamber but dividing short of the apex into two separate canals with separate foramina
• In case if you have doubt about merging canals, then you can place master gutta percha cone in one of the mb canal and either 10/15 number K file or gutta percha cone in another canal. If you feel any resistance and file/gutta percha cone is not reaching upto the working length then that gives the confirmation about merging canals.
‘My first MB2'
It was a case with 16…first I got three canals and I finished preparation with these canals that are MB1, Distal and Palatal. And then accidentally I got one catch which was just palatal to mb1 and when I inserted 10 k file I felt so much of resistance. That time I noticed that is nothing but MB2. ( It’s easy to search when you finish the preparation of main 3 canals)...that moment.. really memorable as it was my 1st MB2… in college I never got MB2 may be I never worked in that way. Then I completed preparation till F1 protaper and obturated. And finally the case was completed. So after that I always search for mb2 and got it in many cases too. So I hope you people will start noticing mb2, happy searching!
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| My 1st MB2 |
Conclusion :
Failure to detect and clean 2nd mesiobuccal canal system will result in decreased long term prognosis. Detection of all the possible canal is utmost important step to maximise endodontic success rate.
References :
- Detection of second Mesiobuccal canals in Maxillary first molars using a new angle of computed tomography. Ali Murat Akram, Cihan Yildirim, Emre Culha, Erhan Demir, Mehmet Ertugrul Ciftci .' Iranian Journal Of Radiology'
- Endodontic management of a maxillary first molars with unusual location of segons Mesiobuccal orifice. RVS Chakradhar Raju, Naresh Sathe, Chandrasekhar Veeramachaneini. ' Journal Of ConservatuCo Dentistry : JCD'
- LOCATING CANALS ,Strategies, Armamentarium and Techniques by Clifford J. Ruddle, DDS . Advanced Endodontics.
- Use of ophthalmic dyes in root canal location. Sashi Nallapati BDS and Gary Glassman DDS
