Abstract : Sensory disturbance such as paresthesia, anesthesia, hypoesthesia and hyperesthesia may be present in the oral cavity, which are caused by many local and systemic factors. Paresthesia is defined as a burning or prickling sensation or partial numbness caused by nerve injury. Paresthesia of the inferior alveolar nerve is quite rare because of the unique anatomy of this nerve. This case report describes the initial treatment and resolution of paresthesia-partial numbness of the inferior alveolar nerve stemming from serious acute purulent periodontitis, as well as the 1-year follow-up.

Abstract : We investigated the effects of power and time of 810-nm Ga-Al-As laser irradiation on the calcification ability of human dental pulp (HDP) cells.

 To investigate the effects of laser power, cultured HDP cells underwent single 810-nm Ga-Al-As laser irradiation at 300 J with total irradiation energy fixed at 0 W/0 s (control group), 0.5 W, 1.0 W, 1.5 W, 2.0 W, 2.5 W or 3.0 W. von Kossa staining, alkaline phosphatase (ALP) activity, and cell number of the HDP cells were determined to evaluate the calcified nodule formation. von Kossa staining was greater in the 1.0 W group or 1.5 W group than in the control group, as were cell number and ALP activity (p<0.05). However, von Kossa staining was lower in the 3.0 W group than in the control group, as were cell number and ALP activity (p<0.05).

 To investigate the effects of laser irradiation time on the calcification ability, HDP cells were irradiated once with the laser at 1.0 W for 0 s (control group), 10 s, 30 s, 50 s, 100 s, 300 s or 500 s. Cell number and ALP activity were enhanced by laser irradiation in a time-dependent manner, and were significantly greater in the 500 s and 300 s groups compared with the control group (p<0.05). Calcified nodule formation in the HDP cells increased in a time-dependent manner after laser irradiation, as revealed by von Kossa staining.

 These results suggested that formation of calcified nodules in HDP cells was enhanced by stimulation under optimum laser irradiation conditions.

Abstract : Objective : The purpose of this study was to evaluate the effect of intracanal dressing with Calcipex Ⅱ^®, a calcium hydroxide intracanal medicament, on the percentage of the gutta-percha-filled area (PGP).

 Methods : Forty-eight simulated straight canals were prepared in clear resin blocks using EndoWave rotary instruments to size 30 (0.06 taper) on apical dimensions. Each type of specimens were divided into two groups (n=24), respectively ; Calcipex Ⅱ^® remaining and without Calcipex Ⅱ^® (control) groups. Specimens were filled with gutta-percha and sealer, Thermafil^®+Canals^®, Thermafil^®+Canals^®-N, Thermafil^®+Sealapex^TM, single-cone+Canals^®, single-cone+Canals^®-N, and single-cone+Sealapex^TM (n=4). All specimens were sectioned horizontally at 1 and 3 mm levels from the working length, and the PGP was measured. Data were analyzed and compared using Kruskal-Wallis and Mann-Whitney tests (P<0.05).

 Results : At 1 mm, no significant differences were found in PGP of Thermafil^®+Canals^®-N, single-cone+Sealapex^TM between the Calcipex Ⅱ^® remaining groups and without Calcipex Ⅱ^® groups (P>0.05). At 3 mm, no significant differences were found in PGP among Thermafil^®+Canals^®, Thermafil^®+Canals^®-N, Thermafil^®+Sealapex^TM, single-cone+Canals^® (P>0.05).

 Conclusions : Thermafil^®+Canals^®-N was least affected by Calcipex Ⅱ^® intracanal medication.

Abstract : Heated gutta-percha and sealer are used in the thermoplastic injection technique. However, high temperature is a problem, with accidents such as burning of the lip or gingiva by the heated needle occurring sometimes. Therefore, a low-temperature type gutta-percha was developed. Two types of gutta-percha having different types of flow, sample 1 and 2, were examined using Obtura Ⅲ^® with the setting temperature of 80°C or 90°C. The effect of root canal sealer was also examined. In both cases of without vertical press or sealer, and without sealer but with vertical press, and at the setting temperature of 80°C or 90°C, filling was poor and gutta-percha could not reach the apex. In the case of with sealer without vertical press, 30 to 60% of filler reached the apex. On the other hand, about 80% of gutta-percha reached the apex in the case of with sealer and vertical press. When sealer was applied to 5 or 1 mm before the apex, there was no difference in effect of inducing gutta-percha to reach the apex. In the lateral canal, almost all samples were filled to about 90%. It is suggested that sealer and vertical press are needed to obtain good root canal filling when using the thermoplastic injection technique.

Abstract : In this case, we removed a fractured endodontic instrument that had over-extended into the periapical tissue using an operative microscope and ultrasonic vibration. The involved maxillary right second molar had undergone endodontic treatment and a complete veneer crown had been placed 7 years earlier. For a few years, the patient had had slight occlusal pain and a feeling of wrongness. When the crown dropped out, the patient saw a local dentist and an endodontic problem was found in the palatal root canal of the involved tooth under roentgenologic examination, so the patient visited our clinic. We tried to remove the instrument fragment and could improve the problem on the 9^th treatment. Follow-up 2.2 years after the root canal treatment showed that both the local condition and roentgenologic findings were good.

Abstract : GT Series X (GTX) rotary files involve a preparation technique starting with a size 20, 0.06 taper (20/.06) instrument without the crown-down sequence. In this study, the shaping ability of this technique was evaluated in comparison with the crown-down technique. Forty simulated S-shaped canals in resin blocks were prepared to 20/.06 as follows : GTX 20/.06 to the working length (2 to 3 cycles) (Group 1) ; GTX 20/.06, 20/.04 followed by 20/.06 (Group 2) ; and crown-down technique starting with GTX 40/.06, GTX 30/.06 and K3 30/.06 (Groups 3-5, respectively). Using image analyzing software, material removal was measured at three measuring levels corresponding to coronal and apical curvatures and 5 mm above the coronal curvature. The preparation time, excluding the time for file change and irrigation, was also recorded. Data were analyzed with the one-way ANOVA and Bonferroni-Dunn test (α=0.05). Groups 1 and 2 required a longer preparation time and removed less material at the inner side of the coronal curvature and 5 mm above the coronal curvature, compared with the other groups. At the apical curvature, all groups showed minimal transportation. It was concluded that, according to the recommended technique, GTX may produce a canal shape with minimal apical transportation and reduced coronal enlargement.

Abstract : It is generally considered difficult to conserve internal resorption perforated teeth. We performed non-surgical endodontic treatment for an internal resorption perforated tooth. After observing the course for more than 10 years, we obtained satisfactory results. The general treatment for internal resorption perforated teeth has been to perform surgical obturation on the perforated region after treating the root canal. However, if the patient does not agree to undergo surgical treatment, it is possible to conserve the tooth by non-surgical treatment if granulation tissue in the root canal can be completely removed and a perfect root canal filling can be achieved.

Abstract : The implant periapical lesion (IPL), which is a possible cause of implant failure, may occur due to the presence of a pre-existing microbial pathology such as endodontic/periodontal lesions. A 27-year-old female patient underwent the placement of a screw-shaped submergible titanium dental implant in the maxillary anterior region. Six months after implant insertion, the patient visited our hospital and presented with a persistent pain resistant to analgesics. A periapical x-ray showed the presence of a radiolucency at the apical portion of the implant ; this image was confirmed by cone beam CT. Root canal treatment was performed to restore the bone defect in the neighborhood of the fixture. This paper presents a case history related to IPL, which was caused by a pre-existing endodontic lesion.

Abstract : This case report describes root canal procedures and prognosis after conservative root canal treatment for three cases with large periapical lesions. The teeth involved had a phoenix abscess with spontaneous pain, a phoenix abscess with gingival swelling and pain, and a radicular cyst spreading to the adjacent tooth and sinus. Sodium hypochlorite solution (NaClO) is the best solvent agent for destruction of the epithelial lining and sub-epithelial hemorrhage of the lesion. The root canals were cleaned with both a biomechanical preparation and a biochemical preparation with sodium hypochlorite and hydrogen peroxide. The use of NaClO for conservative root canal treatment of a large apical lesion tooth promoted drainage of the pus and destruction of the epithelial lining, after which the large lesions quickly changed to granulomatous tissue from a cyst. After disinfecting the root canal, the canals were obturated with gutta-percha and sealer. Radiographic images showed the disappearance of the apical lesion and osteogenic healing, and the longest case also showed a fair course after an 18 years prognosis. This report suggested that a proper procedure using canal irrigation with a solvent agent is effective for the conservative treatment of a large periapical lesion.