Angiogenesis and Lymphangiogenesis in Oral Squamous Cell Carcinoma: Comparison of Japanese and Indian Cases

Chowdhury, Chitta Ranjan,Kirita, Tadaaki,Jose, Maji,Abdullah, Riaz Asian Pacific Journal of Cancer Prevention 2012 Asian Pacific journal of cancer prevention Vol.13 No.7

A comparative study between 17 Japanese and 19 Indian patients with oral squamous cell carcinomas (OSCCs) revealed that the tumour prognostic indicator mean vessel density (MVD) count for angiogenesis was relatively high at 57.1 in Indian as compared to 39.3 in Japanese (P=0.001) cases, whereas the lymph-vessel density (LVD) count for lymphangiogenesis was lower (12.8 vs 48.0, P=0.002). Both male and female Indians had higher MVD counts, but LVD counts were only slightly lower in females. MVD count was relatively high among the cases below 65 years old in both the countries (P=0.4). Japanese cases with Tongue cancer had higher MVD count, but the Indian cases had lower LVD counts. Size-wise, T2 and T3 had higher counts of MVD both in Indian and Japanese cases. MVD and LVD count was higher in grades II and III both in Japanese and Indian cases. There was insignificant difference of the MVD counts among smokers, but the tobacco chewers in Indian cases had higher counts of MVD and LVD (P value by Bartlett test 0.35, 0.57 respectively). The hot-spots of tumour sites had variable rates of lymphocyte infiltration showed higher MVD counts in all the cases. Although the clinical characteristics and demographic variables usually relate to MVD and LVD counts, the tendency of higher values, especially among tobacco chewers, identified as the highest risk group for occurrence of oral cancer needs to be investigated further.

Hepatosplenic T-Cell Lymphoma Diagnosed by Endoscopic Ultrasound-Guided Fine-Needle Biopsy

Yoshiaki Shibata,Mayuko Miyamoto,Wataru Shinomiya,Kumiko Kirita,Sayuri Motomura,Hiroko Hidai,Takeshi Hagino,Yuji Ito 대한소화기내시경학회 2020 Clinical Endoscopy Vol.53 No.3

Brief Report

Effects of implant tilting and the loading direction on the displacement and micromotion of immediately loaded implants: an in vitro experiment and finite element analysis

Tsutomu Sugiura,Kazuhiko Yamamoto,Satoshi Horita,Kazuhiro Murakami,Sadami Tsutsumi,Tadaaki Kirita 대한치주과학회 2017 Journal of Periodontal & Implant Science Vol.47 No.4

Purpose: The purpose of this study was to investigate the effects of implant tilting and the loading direction on the displacement and micromotion (relative displacement between the implant and bone) of immediately loaded implants by in vitro experiments and finite element analysis (FEA). Methods: Six artificial bone blocks were prepared. Six screw-type implants with a length of 10 mm and diameter of 4.3 mm were placed, with 3 positioned axially and 3 tilted. The tilted implants were 30° distally inclined to the axial implants. Vertical and mesiodistal oblique (45° angle) loads of 200 N were applied to the top of the abutment, and the abutment displacement was recorded. Nonlinear finite element models simulating the in vitro experiment were constructed, and the abutment displacement and micromotion were calculated. The data on the abutment displacement from in vitro experiments and FEA were compared, and the validity of the finite element model was evaluated. Results: The abutment displacement was greater under oblique loading than under axial loading and greater for the tilted implants than for the axial implants. The in vitro and FEA results showed satisfactory consistency. The maximum micromotion was 2.8- to 4.1-fold higher under oblique loading than under vertical loading. The maximum micromotion values in the axial and tilted implants were very close under vertical loading. However, in the tilted implant model, the maximum micromotion was 38.7% less than in the axial implant model under oblique loading. The relationship between abutment displacement and micromotion varied according to the loading direction (vertical or oblique) as well as the implant insertion angle (axial or tilted). Conclusions: Tilted implants may have a lower maximum extent of micromotion than axial implants under mesiodistal oblique loading. The maximum micromotion values were strongly influenced by the loading direction. The maximum micromotion values did not reflect the abutment displacement values.

The effects of bone density and crestal cortical bone thickness on micromotion and peri-implant bone strain distribution in an immediately loaded implant: a nonlinear finite element analysis

Sugiura, Tsutomu,Yamamoto, Kazuhiko,Horita, Satoshi,Murakami, Kazuhiro,Tsutsumi, Sadami,Kirita, Tadaaki Korean Academy of Periodontology 2016 Journal of Periodontal & Implant Science Vol.46 No.3

Purpose: This study investigated the effects of bone density and crestal cortical bone thickness at the implant-placement site on micromotion (relative displacement between the implant and bone) and the peri-implant bone strain distribution under immediate-loading conditions. Methods: A three-dimensional finite element model of the posterior mandible with an implant was constructed. Various bone parameters were simulated, including low or high cancellous bone density, low or high crestal cortical bone density, and crestal cortical bone thicknesses ranging from 0.5 to 2.5 mm. Delayed- and immediate-loading conditions were simulated. A buccolingual oblique load of 200 N was applied to the top of the abutment. Results: The maximum extent of micromotion was approximately $100{\mu}m$ in the low-density cancellous bone models, whereas it was under $30{\mu}m$ in the high-density cancellous bone models. Crestal cortical bone thickness significantly affected the maximum micromotion in the low-density cancellous bone models. The minimum principal strain in the peri-implant cortical bone was affected by the density of the crestal cortical bone and cancellous bone to the same degree for both delayed and immediate loading. In the low-density cancellous bone models under immediate loading, the minimum principal strain in the peri-implant cortical bone decreased with an increase in crestal cortical bone thickness. Conclusions: Cancellous bone density may be a critical factor for avoiding excessive micromotion in immediately loaded implants. Crestal cortical bone thickness significantly affected the maximum extent of micromotion and peri-implant bone strain in simulations of low-density cancellous bone under immediate loading.

Effects of implant tilting and the loading direction on the displacement and micromotion of immediately loaded implants: an in vitro experiment and finite element analysis

Sugiura, Tsutomu,Yamamoto, Kazuhiko,Horita, Satoshi,Murakami, Kazuhiro,Tsutsumi, Sadami,Kirita, Tadaaki Korean Academy of Periodontology 2017 Journal of Periodontal & Implant Science Vol.47 No.4

Purpose: The purpose of this study was to investigate the effects of implant tilting and the loading direction on the displacement and micromotion (relative displacement between the implant and bone) of immediately loaded implants by in vitro experiments and finite element analysis (FEA). Methods: Six artificial bone blocks were prepared. Six screw-type implants with a length of 10 mm and diameter of 4.3 mm were placed, with 3 positioned axially and 3 tilted. The tilted implants were $30^{\circ}$ distally inclined to the axial implants. Vertical and mesiodistal oblique ($45^{\circ}$ angle) loads of 200 N were applied to the top of the abutment, and the abutment displacement was recorded. Nonlinear finite element models simulating the in vitro experiment were constructed, and the abutment displacement and micromotion were calculated. The data on the abutment displacement from in vitro experiments and FEA were compared, and the validity of the finite element model was evaluated. Results: The abutment displacement was greater under oblique loading than under axial loading and greater for the tilted implants than for the axial implants. The in vitro and FEA results showed satisfactory consistency. The maximum micromotion was 2.8- to 4.1-fold higher under oblique loading than under vertical loading. The maximum micromotion values in the axial and tilted implants were very close under vertical loading. However, in the tilted implant model, the maximum micromotion was 38.7% less than in the axial implant model under oblique loading. The relationship between abutment displacement and micromotion varied according to the loading direction (vertical or oblique) as well as the implant insertion angle (axial or tilted). Conclusions: Tilted implants may have a lower maximum extent of micromotion than axial implants under mesiodistal oblique loading. The maximum micromotion values were strongly influenced by the loading direction. The maximum micromotion values did not reflect the abutment displacement values.

The effects of bone density and crestal cortical bone thickness on micromotion and peri-implant bone strain distribution in an immediately loaded implant: a nonlinear finite element analysis

Tsutomu Sugiura,Kazuhiko Yamamoto,Satoshi Horita,Kazuhiro Murakami,Sadami Tsutsumi,Tadaaki Kirita 대한치주과학회 2016 Journal of Periodontal & Implant Science Vol.46 No.3

Purpose: This study investigated the effects of bone density and crestal cortical bone thickness at the implant-placement site on micromotion (relative displacement between the implant and bone) and the peri-implant bone strain distribution under immediate-loading conditions. Methods: A three-dimensional finite element model of the posterior mandible with an implant was constructed. Various bone parameters were simulated, including low or high cancellous bone density, low or high crestal cortical bone density, and crestal cortical bone thicknesses ranging from 0.5 to 2.5 mm. Delayed- and immediate-loading conditions were simulated. A buccolingual oblique load of 200 N was applied to the top of the abutment. Results: The maximum extent of micromotion was approximately 100 μm in the low-density cancellous bone models, whereas it was under 30 μm in the high-density cancellous bone models. Crestal cortical bone thickness significantly affected the maximum micromotion in the low-density cancellous bone models. The minimum principal strain in the peri-implant cortical bone was affected by the density of the crestal cortical bone and cancellous bone to the same degree for both delayed and immediate loading. In the low-density cancellous bone models under immediate loading, the minimum principal strain in the peri-implant cortical bone decreased with an increase in crestal cortical bone thickness. Conclusions: Cancellous bone density may be a critical factor for avoiding excessive micromotion in immediately loaded implants. Crestal cortical bone thickness significantly affected the maximum extent of micromotion and peri-implant bone strain in simulations of low-density cancellous bone under immediate loading.

Three-Dimensional Flexible Endoscopy Can Facilitate Efficient and Reliable Endoscopic Hand Suturing: An ex-vivo Study

Jun Omori,Osamu Goto,Kazutoshi Higuchi,Takamitsu Umeda,Naohiko Akimoto,Masahiro Suzuki,Kumiko Kirita,Eriko Koizumi,Hiroto Noda,Teppei Akimoto,Mitsuru Kaise,Katsuhiko Iwakiri 대한소화기내시경학회 2020 Clinical Endoscopy Vol.53 No.3

Background/Aims: Three-dimensional (3D) flexible endoscopy, a new imaging modality that provides a stereoscopic view, canfacilitate endoscopic hand suturing (EHS), a novel intraluminal suturing technique. This ex-vivo pilot study evaluated the usefulnessof 3D endoscopy in EHS. Methods: Four endoscopists (two certified, two non-certified) performed EHS in six sessions on a soft resin pad. Each sessioninvolved five stitches, under alternating 3D and two-dimensional (2D) conditions. Suturing time (sec/session), changes in suturingtime, and accuracy of suturing were compared between 2D and 3D conditions. Results: The mean suturing time was shorter in 3D than in 2D (9.8±3.4 min/session vs. 11.2±5.1 min/session) conditions and EHSwas completed faster in 3D conditions, particularly by non-certified endoscopists. The suturing speed increased as the 3D sessionsprogressed. Error rates (failure to grasp the needle, failure to thread the needle, and puncture retrial) in the 3D condition were lowerthan those in the 2D condition, whereas there was no apparent difference in deviation distance. Conclusions: 3D endoscopy may contribute to increasing the speed and accuracy of EHS in a short time period. Stereoscopicviewing during 3D endoscopy may help in efficient skill acquisition for EHS, particularly among novice endoscopists.