Radix entomolaris (RE) appears more frequently in the Mongolian population than in Caucasian and African populations. A case of root canal treatment of a mandibular first molar with radix entomolaris is reported. The patient was a Japanese male in his 40s with spontaneous pain of #36. On imaging examinations including dental X-rays and cone-beam computed tomography (CBCT), #36 had 3 roots with RE. Before root canal treatment, the operator could understand the root numbers of #36 and the root canal morphology. #36 was examined under the microscope, and root canal treatment was well done. CBCT and use of a microscope provided the operator with effective information for root canal treatment.
There are often cases in which the use of a microscope in treatment allows preservation of a tooth that would ordinarily have been deemed untreatable and extracted. Tools such as cone-beam computed tomography (CBCT), mineral trioxide aggregate (MTA), ultrasonic instruments, nickel-titanium rotary files, and composite resins used in combination with the microscope are also of great benefit in this regard. A case of internal resorption accompanied by perforation at the root furcation of the mandibular left first molar is presented. Conservative treatment was performed under a microscope, using MTA to repair the perforation and then using a bulk-fill type composite resin, obtaining satisfactory results.
We believe that, through the use of a microscope, it is possible to carry out reliable restoration treatment with the direct method even on large cavities, which have conventionally been treated by the indirect method. This allows elective removal of tooth structure to be kept to a minimum, in line with the concept of Minimal Intervention Dentistry1. A case in which a microscope was used to carry out a composite resin restoration for a large cavity on the proximal surface of an upper premolar extending under the gingival margin, with satisfactory results obtained after 6 years and 1 month of follow-up, is reported. This case suggests the advantages of using a microscope for direct method restorations.
Severely calcified root canals cause pulp canal obliteration and it is difficult to treat the root canal precisely. Here, a successful and safe treatment for severe calcification is introduced. The root canal orifice was searched based on cone-beam computed tomography images. An access opening was then created using a diamond-coated ultrasonic tip, and excessive removal of root dentin was avoided using a surgical microscope. Root canal preparation was safely performed using nickel-titanium rotary files. Clinical skills to manipulate these tools are necessary for the treatment of these types of cases.
Aims: The mandibular first molar is an important tooth that is the key to occlusion. However, since it is among the earlier permanent teeth to erupt, it often requires dental treatment such as root canal treatment. The success rate of root canal treatment is by no means high, so there is a need to consider and address the underlying causes. The mandibular first molar is known to sometimes have an additional distolingual root (DLR) called the radix entomolaris, and we have previously clarified the prevalence of this root in Japanese people and the prevalence in treated teeth. The purpose of the present study was to clarify the causes of apical lesions in DLRs.
Material and Methods: The subjects were 228 patients who had cone-beam computed tomography (CBCT) scans during the period from February 2019 to July 2020. Data on 70 three-rooted mandibular first molars with a separate DLR in which the whole tooth was visible on CBCT were sequentially extracted. The number of three-rooted mandibular first molars with a separate DLR, the root canal treatment status, and the presence or otherwise of root apical region radiolucency were recorded, and the prevalence of DLR and the causes of apical lesions were analyzed.
Result: The prevalence of DLR in the present study was 30.7%. The proportion of three-rooted mandibular first molars with a separate DLR that had undergone root canal treatment was 42.9%, and the CBCT findings showed radiolucency in the root apical region in 31.4% of these. The success rate in teeth that had undergone root canal treatment was 26.7%, and the rate of failure, in which root apical region radiolucency was found, was 73.3%. The breakdown of failures showed that the root canal was overlooked in 36.4% of cases, with zipping/ledging/perforation in 63.6% of cases, and broken instruments in 0% of cases. The results of the analysis showed that there was a significantly greater proportion of overlooked root canals with root apical region radiolucency than with no root apical radiolucency (p<0.01). With teeth that had undergone root canal treatment, root apical radiolucency was significantly more common in teeth with zipping/ledging/perforation (p<0.01).
Conclusions: The results showed that the success rate of root canal treatment of three-rooted mandibular first molars with a separate DLR in Japanese people was 26.7%. Overlooking the DLR and zipping/ledging/perforation were shown to be causes of apical lesions.
A 46-year-old Asian female was referred for endodontic treatment of tooth #36. The tooth was previously restored with a PFM crown. After intraoral examination and radiographic finding, the tooth was diagnosed with Pulpal Necrosis and Asymptomatic Periradicular Periodontitis. A root canal treatment was undertaken. Seventeen months later, treatment failure ensured. This case report discusses the causes of failure along with strategies to save the tooth.