•Purpose: assess the ability to locate and negotiate mesial canals in 1st and 2nd molars using magnifying loupes and microscopes.
•N= 96 (48 – 1st molars / 48 – 2nd molars)
•Exclusion criteria: Previous RCT, C shaped, calcified canals, deficient coronal structure, abnormal anatomy, fused or single roots, C-shaped canals.
- Follows previous study on maxillary molars
- Periapical radiograph taken from B-L direction.
- Teeth were mounted in mannequins to simulate clinical situation.
- Standard access was made in all teeth using loups (4.5X)
- Teeth were divided into 3 groups each assigned to one endodontist to assess the mesial canals.
- 1st stage: only loupes were used, troughing with ultrasonic tips. Size 6 k files. canal was negotiated until it was risky to continue further apically, mesial canal was no longer detectable, or perforation occurred.
- 2nd stage: microscope was used instead of loups.
- 3rd stage: RG was taken with k file in the mesial canal.
- 4th stage : chamber photographed with the aid of a stereomicroscope. # of canals and location was assessed.
- 5th stage: RG taken from M aspect after resecting D root depth of dentin removal was measured.
- 6th stage: All molars were sectioned at :1 mm, 4 mm, and 8 mm from the apex. To assess for mesial canal
Most highlighted Results:
•use of microscope improves increased the allocation of middle mesial canal in 1st and 2nd molars (16% to 18%).
•Incidence of middle mesial canal in 1st molar was (18%), 2nd molar (22%) •45% accessory mesial canals were close to ML canal.
•30% of accessory mesial canals were in the middle.
•All accessory mesial canals joined a main canal. 1st molar : 42% joined MB, 2nd :55% joined ML.
•None of accessory canals were observed 4 mm from the apex.
•Depth of dentin removed to negotiate or rule out was 1 mm in 1st mandibular molar, 0.7 in 2nd molar.
Impact of visual aids on detection of the canal, understanding the anatomy of accessory mesial canal could help in detecting, instrumenting extra canals.