Objective:To observe the temperature vaxiation in the pulp chamber during Nd-YAG laser irradiation at tooth cervical portion.Methods:60 extracted permanent teeth were divided into 3 groups (anterior teeth,premolars and molars,n =20).The teeth in each group were further divided into 4 subgroups according to the laser power setting (0.4 W,0.8 W)and interval time(1 0 s,20 s)(n =5).After canal preparation the teeth were fixed and filmed using the parallel projection technique.the thickness of the buccal pulp chamber wall was measured by graphic analyzing software.The buccal cervical portion of the teeth was irradiated through 200 μm optical fiber,Temperature in the pulp was measured by K type thermo-electric couples fixed to the pulp chamber wall.Re-sults:The temperature inside the chamber increased with the higher power setting(P <0.01 ),under the same power setting,longer irradiation duration caused higher temperature rise(P <0.01 ).Greater chamber wall thickness was associated with lower temperature rise.Conclusion:The temperature rise in the pulp chamber during laser irradiation is correlated with laser power setting and the thickness of the irradiated tooth tissue.

Objective:To investigate the clinical incidence of the three mesial root canals of mandibular first molars. Methods: Incidence and morphology of the three mesial root canals of mandibular first molars were determined by probing the fissure or grooves between the mesiobuccal and mesiolingual root canal orifices and X-ray analysis. Results: Of the 222 mandibular first molars, 13 of the molars had three mesial root canals. The incidence rate was 5.85 %. Conclusion: Although the incidence rate of the three mesial root canals of mandibular first molars was very low, the dental operative microscope was helpful for the diagnosis.

OBJECTIVETo evaluate the adjunctive effect of diode laser irradiation for the treatment of periodontal-endodontic combined lesions.

METHODS30 cases with periodontal-endodontic combined lesions were selected. All cases were randomly divided into experimental group and control group (n=15). In the control group, patients were treated with root canal therapy and conservative periodontal treatment (scaling and root planning), and patients in the experimental group were treated with root canal therapy and conservative periodontal treatment followed by diode laser irradiation. Clinical measurements including pocket probing depth (PPD), clinical attachment level (CAL), modified bleeding index (mBI), periapical index (PAI) were taken before treatment (baseline). Three and six months after the treatment, the adjunctive effects of diode laser in the treatment of periodontal-endodontic combined lesions were evaluated.

RESULTSThree months after the treatment, the average PPD, CAL and mBI levels were reduced significantly in both groups. But the average PPD reduction in the experimental group was significantly greater (P<0.05) than in control group. However the average CAL and mBI reduction were not significantly different between two groups. Six months after the treatment, the average PPD, CAL and mBI levels were further reduced in the experiment group, but not in the control group. The average PAI levels were reduced significantly in both groups, but the PAI reduction was not significantly different between two groups.

CONCLUSIONThe use of diode laser as an adjunct procedure in the treatment of periodontal-endodontic combined lesions can aid in achieving success.

OBJECTIVEThis in vitro study is to evaluate the effect of ultrasonic power settings and cooling methods on fracture behavior of the separated nickel titanium instruments during ultrasonic removal.

METHODS40 discarded and 10 new nickel titanium instruments were used to establish the separated instrument removal model. The discarded instruments were divided into four groups according to two ultrasonic power settings(6 or 10) and different cooling methods (using water coolant or without using water coolant), and all the new instruments were put into the group in which ultrasonic vibration was used at a higher power setting (10) without using water coolant. The time required for fracture of the separated instruments was recorded.

RESULTSThe time was longer with statistical significance at a lower power setting compared with that at a higher power setting regardless of the use of water coolant. The time was longer with statistical significance by the use of water coolant compared with that without using coolant regardless of power settings (6 or 10). The time required for fracture of the new instruments was longer than that of the discarded instruments with statistical significance.

CONCLUSIONDuring ultrasonic removal of separated nickel titanium instruments, water coolant could decrease the occurrence of fracture. When removing separated nickel titanium instruments with ultrasonic vibration, an attempt without coolant shouldn't be made at a higher power setting.

According to literature, the incidence of three-canal maxillary first premolar is between 0.5% and 7.5%. The two types of three-canal maxillary premolars are two-rooted and three-rooted three-canal maxillary premolars. Most case reports in Chinese literature focus on three-rooted three-canal maxillary premolars. To our knowledge, no domestic case report on two-rooted three-canal maxillary premolar has been published. In this study, we describe the root canal treatment of a two-rooted three-canal maxillary premolar.

According to literature, the incidence of three-canal maxillary first premolar is between 0.5% and 7.5%. The two types of three-canal maxillary premolars are two-rooted and three-rooted three-canal maxillary premolars. Most case reports in Chinese literature focus on three-rooted three-canal maxillary premolars. To our knowledge, no domestic case report on two-rooted three-canal maxillary premolar has been published. In this study, we describe the root canal treatment of a two-rooted three-canal maxillary premolar.
Bicuspid ; Dental Pulp Cavity ; Humans ; Maxilla ; Publishing ; Root Canal Therapy ; Tooth Root

Objective:To explore the efficacy of different unipolar electrocoagulation power on pathological injury of porcine kidney suffering suture-free partial nephrectomy (SFPN).Methods:From April 2018 to July 2018, nine Guizhou pigs were selected, with an average age of 3 years and an average weight of 48 kg. According to different hemostatic power of unipolar electrocoagulation during open partial nephrectomy, they were divided into three groups(60W group, 80W group, and 100W group), with 3 in each group. The left kidney was exposed with a surgical incision, parallel to the lumbosacral muscle.The left renal artery was clamped and about 2 cm renal tissue was excised at the middle pole of the left kidney. 60W, 80W and 100W were used by unipolar electrocoagulation for hemostasis until no bleeding occurred after the artery clamp was released. The total ischemia time was controlled within 20 min. Temperature was measured by a multi-channel thermometer probe which was inserted into the healthy kidney tissue at a distance of 2 mm, 5 mm, and 10 mm away from the unipolar electrocoagulation hook, and the upper pole of the kidney far away from the operation area. The time of operation, the volume of renal bleeding, the time of hemostasis and the temperature were recorded. On the 7th day after operation, the left kidneys were taken and the pathological changes were observed by toluidine blue staining.Results:All operations were completed safely and successfully. The operation time in 60W group, 80W group, and 100W group was (41.2±5.5)min, (35.1±3.7)min, (31.3±2.2)min , respectively. There was no significant difference of operation time among those group ( P>0.05). The blood loss of renal was (35.3±4.1)ml, (21.4±4.7)ml, (15.3±4.1)ml, respectively. The blood loss in the 100W group and 80W group was less than that in the 60W group ( P<0.05). And the blood loss in the 100W group was less than that in the 80W group ( P<0.05). The hemostasis time was (15.2±1.9)min, (10.1±1.4)min, (6.4±0.8)min. The hemostasis time in the 100W and 80W groups was less than that in the 60W group ( P<0.05). And the hemostasis time in the 100W group was less than that in the 80W group ( P<0.05). At the place of 10 mm away from the electrocoagulation hook, the temperature in the three groups were (33.1±1.1)℃, (34.0±1.0)℃, (34.3±0.6)℃, which was not significantly different from that of the respective upper poles. And there was no significant difference between the three groups( P>0.05). At the place of 5 mm and 2 mm away from the electrocoagulation hook, the temperature in the 100W group (41.7±1.3)℃, (61.4±6.4)℃ and the 80W group (38.6±2.4)℃, (50.3±6.0)℃ was higher than that in the 60W group (36.9±4.1)℃, (42.0±4.7)℃, and the temperature in 100W group is higher than that in 80W group ( P<0.05). When the power was 60W, 80W or 100W, the temperature in the place 10 mm away from the electrocoagulation hook was less than that in the place 5 mm away from the electrocoagulation hook ( P<0.05), and the temperature of the place 5 mm away from the electrocoagulation hook was lower than that of the place 2 mm away from the electrocoagulation hook ( P<0.05). The total pathological injury depth of wounds in 60W, 80W, 100W group was (7 323±50)μm, (8 119±100)μm, (8 896±40)μm, respectively. The depth in 100W group and 80W group was deeper than that in 60W group ( P<0.05), and the depth in 100W group was deeper than that in 80W group ( P<0.05). Conclusions:In SFPN, the hemostatic effect of three different monopolar electrocoagulation output power is satisfactory. With the increase of power, the hemostasis speed is faster. However, the temperature of surrounding healthy renal tissue would be higher, and the total pathological injury depth would be deeper.

Objective:To establish an isotope dilution liquid chromatography-tandem mass spectrometry (ID-LC-MS/MS) method for the determination of L-tryptophan and its metabolites in serum.Methods:The methodology was established and evaluated using serum samples collected from 166 healthy subjects undergoing physical examinations at West China Hospital from November 2022 to January 2023 were collected. Isotope-labeled markers of L-tryptophan (Trp), L-kynurenine (Kyn), and kynurenic acid (KA) were used as internal standards. After protein precipitation treatment of serum samples, LC-MS/MS was used to determine Trp, Kyn, and KA simultaneously. The selectivity, specificity, linearity, detection limit (LOD), quantification limit (LOQ), carry-over, precision, recovery rate, matrix effect, and dilution integrity of the method were evaluated.Results:The linearity of Trp, Kyn, and KA was demonstrated to be 0.999. The LODs were 0.10 μmol/L, 0.01 μmol/L and 1.00 nmol/L, respectively. The LOQs were 0.20 μmol/L, 0.04 μmol/L and 2.00 nmol/L, respectively. The intra-batch precision and inter-batch precision were below<10%. The average recovery rate and the relative matrix effect were all about 100%. The samples over the upper limit of quantitation can be diluted up to 16 times. The Trp concentration, Kyn concentration, KA concentration, Kyn/Trp ratio, and KA/Kyn ratio in serum of healthy subjects were 59.55±10.92 μmol/L, 1.85±0.43 μmol/L, 39.89±17.93 nmol/L, (31.64±8.19)×10 -3 and 21.51±6.72, respectively. Conclusion:An ID-LC-MS/MS method was successfully established for the quantitative determination of Trp, Kyn, and KA in serum. The method proved to be simple, rapid, sensitive, accurate, and reliable, providing robust support for clinical research related to these analytes.