[ ABSTRACT] AIM:To investigate the role of chronic psychological stress on periodontitis and the effects of hy-perbaric oxygen ( HBO) on periodontitis with psychological stress in rats.METHODS:Male special pathogen-free Wistar rats (n=80) were randomly divided into 4 groups:(1)normal control group;(2)experimental periodontitis group:the pe-riodontitis model was induced by wrapping 3/0 silk ligature inoculated with Porphyromonas gingivalis around the left maxil-lary second molar of the rats; ( 3 ) psychological stress stimulation group; ( 4 ) periodontitis model with stress stimulation group.Psychological stress was removed at the 9th week after ligature, and 4 rats from each experimental group were ran-domly chosen for HBO treatment.The rats were sacrificed at the 2nd, 4th, 8th and 10th weeks after ligature.The levels of blood glucose, adrenocorticotropic hormone ( ACTH) , corticosterone and adrenaline were measured as the stress markers. The histological changes of periodontal tissues were observed under microscope with HE staining.RESULTS:The levels of blood glucose, ACTH, corticosterone and adrenaline in psychological stress stimulation group and periodontitis with stress group were significantly higher than those in control group and experimental periodontitis group at the 2nd and 4th weeks af-ter ligature (P<0.05).The levels of the stress markers were significantly lower than those in untreated groups in the 10th week after HBO (P<0.01).The sites of gingival attachment were normal in control group and psychological stress stimu-lation group.Periodontal pocket, and periodontal attachment loss ( AL) were observed in experimental periodontitis group. The tissue damage was much heavier in periodontitis model with stress stimulation group as the furcation of tooth was ex-posed and the tissue damage was observed on both sides of the adjacent teeth.No significant difference of AL between psy-chological stress stimulation group and normal control group during the experiment was observed.The AL in periodontal model with stress stimulating group was significantly higher than that in experimental periodontitis group at the 2nd, 4th and 8th weeks (P<0.01).The level of AL was attenuated at the 10th week after HBO (P<0.01).No difference of histologi-cal change in periodontal tissues was observed between control group and psychological stress stimulation group.Severer in-flammatory changes and alveolar bone destruction were observed in periodontitis with stress group than those in experimental periodontitis group.The levels of inflammation reduced at the 10th week after HBO.CONCLUSION:Stress stimulation is one of the inducing factors of periodontitis in rats, which aggravates periodontitis.HBO may represent a useful way in trea-ting psychological stress periodontitis.

Objective To compare the Roussouly classification of old thoracolumbar fractures combined with post-traumatic kyphosis with that of normal adults, evaluate the effect of different kyphosis angles on sagittal curvature of the thoracolumbar spine so as to provide a theoretical basis for the clinical status and clinical treatment plan of old thoracolumbar fractures combined with post-traumatic kyphosis.Methods A retrospective case control study was made on 49 cases of old thoracolumbar fractures with post-traumatic kyphosis treated from January 2014 to December 2015 (fracture group).Damaged segments of the spine were T11 in four cases, T12 in 14, L1 in 25 and L2 in six.Another 52 normal adult volunteers were chosen as controls.Whole spine X-ray film of the two groups was taken, and the difference in Roussouly classification of the sagittal spine curvature was compared between the two groups.Patients in fracture group were separated into subgroups depending on the Cobb angle (0°-10°, 10°-20°, 20°-30°, 30°-40°, respectively), and the difference in Roussouly classification was compared among subgroups.Results Roussouly classification in control group was five cases of type 1, 12 tpye 2, 25 type 3 and 10 type 4.Results in fracture group was 14 cases of type 1, 11 type 2, eight type 3 and 16 type 4.There were significant differences in Roussouly types between the two groups (P<0.05).According to Roussouly classification, there were two cases of types 1 and 2 and seven cases of types 3 and 4 in subgroup of Cobb angle between 0°-10°;four cases of types 1 and 2 and 10 cases of types 3 and 4 in subgroup of Cobb angle between 10°-20°;12 cases of types 1 and 2 and four cases of types 3 and 4 in subgroup of Cobb angle between 20°-30°;seven cases of types 1 and 2 and three cases of types 3 and 4 in subgroup of Cobb angle between 30°-40°.There were significant differences in Roussouly types among subgroups (P<0.05).Further, Roussouly types 1 and 2 were significantly increased when the Cobb angle was >20° (P<0.05).Conclusions Post-traumatic kyphosis in old thoracolumbar fractures affects spine sagittal curvature.Patients with sagittal spinal imbalance (Roussouly types 1 and 2) are more with increased Cobb angle.Moreover, Cobb angle >20°may be the reference basis for clinical intervention.

As the robotic assisted single port surgery arousing attention, a novel single-arm single-port micro-traumatic laparoscopic robotic surgical system is proposed in this study. From the perspective of the mechanics, joints with high rigidity and high reliability were utilized to realize the remote center of motion (RCM). Besides, the cost of consumables was reduced by adding the support of the rigid endoscope. From the perspective of the algorithm, high-precision motion control method and feedback force protection mechanism were implemented. The effectiveness of the aforementioned characteristics were verified by five clinical experiments of cholecystectomy. The results showed that the system is able to reduce the amount of bleeding, accelerate the patient recovery, reduce the infection risk and shorten the learning period. The robotic surgical system had significant clinical application value.
Humans ; Robotic Surgical Procedures ; Reproducibility of Results ; Laparoscopy ; Motion