OBJECTIVETo assess the temperature variation of the root surface using Nd: YAG laser irradiation in the root canal with different power and to evaluate the safety of laser application on the periodontal region.

METHODSThirty extracted human teeth with single-roots were collected. The teeth were cross-sectioned in the cervical portion, standardizing the roots at a 12-mm length. The roots were used as specimen. The roots were radiographed in the buccal-lingual direction to measure the thickness of the proximal walls, by means of a digital radiographic system. The specimens were divided into three groups according to the laser potency (1.5, 3.0, and 4.5 W). Each group was subdivided into two subgroups according to laser frequency (15 and 30 Hz). With the Nd: YAG laser irradiation for 20 s, the temperature variation of the root surface was monitored by thermocouples located at different parts of the root external wall and recorded by digital thermometers.

RESULTSThe groups irradiated with 4.5 W presented the greatest temperature variation (above 10°C), followed by 3.0 and 1.5 W. The temperatures were statistically different (P < 0.01). The groups irradiated in the same potency, regardless of whether 15 Hz or 30 Hz was used, presented with no statistical difference (P > 0.05). The apical half of the root presented statistically higher temperature rises than the cervical half of the root (P < 0.01).

CONCLUSIONThe temperature variation of the root surface was associated with laser power, irradiation time, and the thickness of dentin. Application of Nd: YAG laser in the root at 1.5 W for 20 s can safely be used in endodontic treatment.

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.

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.

Objective:To establish the quality standard for Sipunculus nudus polysaccharide. Methods:The water content, igni-tion residues and heavy metals in Sipunculus nudus polysaccharide were determined. Authrone-sulfuric acid colorimetry was used to de-termine the polysaccharide content. Results: The water content in the polysaccharide should not exceed 5. 0%, ignition residues should not exceed 1. 0%, and the content of heavy metals should not exceed 20 ppm. The polysaccharide content should exceed 80%( glucose) . Conclusion:The method is accurate and simple, and can be effectively used in the quality control of polysaccharide in Sipunculus nudus Linnaeu.

Objective:To prepare old tea buccal tablets using wet granulation method and optimize the preparation technology. Methods:The amount of each adjuvant was studied by single factor experiments, and the formula of the buccal tablets was optimized by the orthogonal experiments using taste and disintegration time as indices. Results:The optimal formula was composed of old tea ex-tract 30 g,mannitol 60g,PEG6000 20 g,aspartame 10 g,citric acid 10 g and menthol crystal 1 g. All the tested indices including ap-pearance, hardness and disintegration time met the requirements described in Chinese pharmacopeia. Conclusion: The preparation technology is reasonable and feasible for the industrial production.

Objective To investigate the radioprotective effect of cimetidine on survival rate and hematopoietic system in acutely irradiated mice.Methods The total body irradiation doses were 6.0Gy and 8.0Gy respectively at 1.01Gy/min rate. Sixty healthy male C57BL/6 mice were randomly divided into control group, model group, positive-drug (523) group and cimetidine groups (33.3mg/kg, 100mg/kg and 300mg/kg). Each group had ten mice. The mice were given intragastric administration of cimetidine for 6d before the irradiation in cimetidine groups, and 523 was administered before irradiation once a day for one day in 523 group, and at 5h after irradiation, was given again. The 30d survival rate after 8.0Gy irradiation was recorded. The peripheral blood cells, bone marrow DNA content and frequency of micronucleated polychromatic erythrocytes (fMNPCE) were determined 30d after 6.0Gy irradiation.Results After 8.0Gy irradiation, all the mice died on 21th day in model control group. The survival rates in cimetidine groups were 50%, 20% and 30%, respectively. After 6.0Gy irradiation on 30th day, compared with control group, the peripheral white blood cells (WBC) and bone marrow DNA content were decreased significantly (P<0.01,P<0.05) in model group, and fMNPCE was increased significantly (P<0.05). Compared with model group, WBC was significantly increased in 300mg/kg cimetidine group (P<0.01). In cimetidine groups, the bone marrow DNA content was increased significantly after irradiation (P<0.01 orP<0.05), and the fMNPCE was decreased significantly (P<0.01 orP<0.05) and tended towards normal.Conclusion Cimetidine could improve 30d survival rate of acutely irradiated mice and has good protective effect on hematopoietic system.

Objective To discuss clinical application,value and effect of tracheal stent in surgical operation for tracheostenosis caused by thyroid tumor.Methods Clinical data of 6 patients with tracheal stenosis and dyspnea caused by thyroid tumor invasiveness or tracheal compression from Oct.2015 to Sep.2016 were retrospectively analyzed.Of the 6 patients,1 case had nodular goiter and 5 cases had differentiated thyroid carcinoma(DTC).Results All patients had dyspnea caused by thyroid tumor invasiveness or tracheal compression.Dyspnea relieved dramatically after tracheal stent was implantated under local anesthesia.Thyroidectomy was given later,with intraoperative tracheal intubation as well as anesthesia,and the surgery finally succeeded.One case with benign multinodular goiter received complete resection and 5 cases with DTC invading the trachea received complete resection of thyroid and neck lymph node dissection,followed by end-to-end anastomosis of invaded trachea sleeve resection.All patients got stage Ⅰ healing in surgical wound.Five cases received radioactive 131I treatment as well as TSH suppression therapy after DTC surgery.All patients were alive and disease-free after a follow-up of 4 to 15 months.Conclusions For patients with tracheostenosis caused by thyroid tumor invasiveness or tracheal compression,operation under cardiopulmonary bypass is necessary if tracheal intubation is difficult.For hospitals without cardiopulmonary bypass,tracheal stent implantation can effectively relieve dyspnea symptom and reduce risk of tracheal intubation under anesthesia,which provides possibility for surgical treatment.

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