# Laser Doppler for Accurate Diagnosis of Oehler's Type III Dens Invagnatus: A Case Report
## 2 Case Report
However, the material should be thick enough for sealing. MTA, which is more biocompatible, was applied as the filling to the pseudo canal. Figure 3: Different sections in cone-beam computed tomography. (**a**) From the axial view, “pseudo-canal” can be observed on the mesial side, surrounded by the enamel. (**b**) The opening of the invagination near CDJ can be seen in the “pseudo-canal”, in the middle-third of the root. (**c**) From the CBCT coronal view, we can observe that the pseudo canal was located near the core part. (**d**) The CBCT sagittal view showing that the buccal side of the pseudo canal with the opening of the invagination near the cimento-enamel junction, and it was adjacent with a well-defined unilocular peri-invagination radiolucent lesion with a size of 8 mm \(\times\) 9 mm \(\times\) 12 mm. In the first appointment, the access cavity of the invagination was carefully prepared after rubber dam isolation. A surgical operating microscope (OPMI(r) pico, Carl Zeiss, Oberkochen, Germany) was used to prevent damage to the main canal and for precision. Based on the information from CBCT images regarding the extent, position, and pulpal involvement of the invagination, the pseudo root canal of tooth 12 was located precisely (Figure 4a). With the help of X-ray imaging and Root ZX mini apex locator (J. Morita Corp., Tokyo, Japan), a 13-mm working length was confirmed (Figure 2b). The pseudo-canal that appeared to be invaginated was instrumented with K-files up to a size 80 apical master file. During instrumentation, the \"pseudo-canal\" was immersed in 3% sodium hypochlorite solution and thoroughly rinsed between file changes. After removing the biofilm present on the root canal wall, calcium hydroxide was applied as the intracanal medication for chemical disinfection. Then, the entrance of the operated cavity was covered with 3-mm-thick Cavit (3M ESPE US, Norristown, PA, USA.) for 12 days. At the second appointment, the patient returned for a follow-up completely asymptomatic. The temporary restorative materials were removed under rubber dam isolation. Sodium hypochlorite irrigation with a three percent concentration solution, ISO size 40 stainless steel hand files, and passive ultrasonic irrigation (Obtura Spartan, Algonquin, IL, USA) were used for removing the calcium hydroxide paste. After thorough rinsing, a microscopic examination was performed. The amount of residual calcium hydroxide was minimized to promote the subsequent mineral trioxide aggregate (MTA) sealing. At this time, it was recommended that root canal filling be performed on the pseudo root canal because the infection had been controlled. In addition, follow-up was recommended because the main canal was still vital, without any symptoms. Furthermore, the pseudo canal was infected. Due to the necrotic invagination with an open apex, either apexification or revascularization can be selected, considering the opening on the cement-enamel junction part of the root canal with a short working length. However, the material should be at least 3-mm, which is thick enough for sealing. Therefore, we chose MTA (Dentsply Tulsa Dental, Tulsa, OK, USA), which is more biocompatible as the filling for the invaginated canal (Figure 4b). A final rinse was performed with normal saline. A sterilized paper needle was used to confirm that the \"pseudo-canal\" was dry, without exudation of liquid, followed by MTA preparation in accordance with the manufacturer's instructions and recommendations. Figure 4: Microscopic photos during the treatment procedure. (**a**) The “pseudo-canal” was accurately located under the microscope at a magnification of X9.6 to avoid excessive dental tissue loss. (**b**) Dense mineral trioxide aggregate was filled-in after thorough debridement. MTA was applied in layers inside the \"pseudo-canal\" with proper squeezing and packing. A wet cotton ball was placed inside the root canal to accelerate material hardening. Subsequently, the root canal opening was sealed with Cavit.