Gripping and Anchoring Effects on the Mechanical Strengths of Orthodontic Microimplants.

PURPOSE: The aim of this study was to evaluate the mechanical strengths in 5 different designs of orthodontic microimplants by analyzing their configuration of structure. MATERIALS AND METHODS: Thirty microimplants of 5 types (diameter 1.5 mm: type A, B, and C; diameter 1.3 mm: type D and E) were assessed. All microimplants were manually driven into the artificial bones at a 7-mm depth. The anchor area (AA), gripping area (GA), insertion torque (IT), Periotest value (PTV), and pullout strength (PS) were measured. Intergroup and intragroup comparisons were used to detect their significant differences. RESULTS: In the intergroup comparison, type D had a least IT (4.5 Ncm). In the PTV analysis, type B had the largest AA (7.76 mm) and its PTV (1.6) was significantly least than the others. In the PS test, type C had the largest GA (2.40 mm) and its PS was the largest. Intragroup comparisons (IT and PS), type A, and type E presented positively significant correlation. GA revealed positive with PS, and AA showed reverse tendency with PTV. CONCLUSION: The more AA of microimplants, the more stable they are. The more GA of microimplants, the more PS they are. Therefore, type C was better than the others because it had the largest GA and second largest AA.

Andrographolide relieved pathological pain generated by spared nerve injury model in mice.

CONTEXT: Andrographolide (Andro), found in large quantities in Andrographis paniculata Nees (Acanthaceae), is anti-inflammatory, especially in the central nervous system (CNS) glia. OBJECTIVE: The objective of this study is to test Andro's ability to reduce allodynia in a spared nerve injury model. MATERIAL AND METHODS: Male 30 g BalbC mice were divided into four groups: (1) Sham-operated control (Sham-group); (2) nerve injured and treated with saline (Saline-group); (3) nerve injured and treated with Andro (Andro-group); (4) nerve injured and treated with non-steroidal anti-inflammatory drugs (NSAIDS) (NSAIDS-group). Andro or NSAIDS (diclofenac salt) were injected intraperitoneally at 5 mg/kg body weight daily. Mechanical allodynia was assessed by von Frey tests at 3, 7, and 14 d. For immunohistochemical analysis, samples were collected at 7 d. RESULTS: The threshold for inducing allodynia increased and the response percentage reduced in the Andro-group when compared with the Saline-group, as well as when compared with NSAIDS groups throughout 3-14 d. The ratio of threshold for OP-Andro/OP-saline and for OP-Andro/OP-NSAIDS groups was 20.42 and 11.67 at 14 d, respectively. The ratio of response percentage for OP-Andro/OP-saline and for OP-Andro/OP-NSAIDS was 0.32 and 0.39 at 14 d, respectively. Interleukin-1 (IL-1) immunostaining in the spinal cord was reduced in the Andro-group. Astrocytic activities were not significantly reduced in the Andro-group compared with the Saline-group at 7 d post-operation (PO) Conclusions: Andro reduced mechanical allodynia more than NSAIDS at the same concentration, and the observed behaviour was associated with a reduction in inflammatory cytokine produced in the spinal cord.

Mechanical strength of orthodontic infrazygomatic mini-implants.

Orthodontic anchorages have recently been reinforced by newly developed mini-implants. The aim of the present study was to investigate the mechanical strengths of infrazygomatic mini-implants. We measured the insertion torque and pull-out strength of three brands of infrazygomatic mini-implants (AbsoAnchors, Bioray, and Lomas). All three mini-implants were 2 mm in diameter, and five of each brand were manually driven 6 mm into artificial bone. Significant differences among the brands were investigated with Kruskal-Wallis tests. We found no significant relationship between insertion torque and pull-out strength in any individual brand. Among the three brands of infrazygomatic mini-implants, we found no significant difference in mechanical strength. The design of an infrazygomatic mini-implant may be the most important factor determining its mechanical strength.

Horizontal pull-out strength of orthodontic infrazygomatic mini-implant: an in vitro study.

PURPOSE: New modified mini-implants have recently come into use for reinforcing skeletal anchorage in orthodontic application. The aim of this study was to investigate the influence of the design of a mini-implant on its mechanical strength. MATERIALS AND METHODS: We measured the insertion torques and horizontal pull-out strengths of 3 brands of infrazygomatic mini-implants (AbsoAnchor, Bioray, and Lomas; 2 mm for all). Five implants of each brand were manually driven 6 mm into the artificial bone. Significant differences in various parameters among the brands were investigated with the Kruskal-Wallis test. RESULTS: There was no significant relationship between insertion torque and horizontal pull-out strength. The Bioray mini-implants had significantly greater horizontal pull-out strength than the AbsoAnchor mini-implants. CONCLUSIONS: The design of the mini-implant can influence its insertion torque and horizontal pull-out strength. In our findings, the horizontal pull-out strength of all mini-implants placed in the infrazygomatic crest was significantly greater than the orthodontic force applied.

Purification of kavalactones from Alpinia zerumbet and their protective actions against hydrogen peroxide-induced cytotoxicity in PC12 cells.

This study found that fruit shells of shell ginger (Alpinia zerumbet) are a rich source of the kavalactones dihydro-5,6-dehydrokavain (DDK) and 5,6-dehydrokavain (DK). The fruit shell extraction with hexane resulted in good purity and higher yields of DDK and DK than did chloroform, ethanol, 10% ethanol, methanol or water. Additionally, this study examined the neuroprotective effects of DDK and DK against H2O2-induced cytotoxicity in PC12 cells and the possible molecular mechanisms involved. 16 h after stimulation with 400 µM H2O2, the viability (MTT reduction) of PC12 cells decreased while membrane damage (LDH release) was noticeably increased. However, pretreatment for 6 h with DDK and DK (1 µM, 5 µM, 10 µM and 50 µM) rescued PC12 cells from H2O2-induced cytotoxicity, as evidenced by decreased LDH release and increased cell viability. DDK and DK inhibit the MAPK family member p38, activate AKT, and reduce caspase-3 activity. DDK also reduced the oxidative status in H2O2-treated PC12 cells. Together, our data indicate that the A. zerumbet constituents, DDK and DK, exert a protective effect against oxidative stress-induced PC12 cell death and that the regulation of p-Akt and the p38 MAPK, and of oxidative states may be involved.

Effects of andrographolide and 14-deoxy-11,12-didehydroandrographolide on cultured primary astrocytes and PC12 cells.

AIMS: To test the effects of andrographolide (AP1) and 14-deoxy-11,12-didehydroandrographolide (AP2) on pheochromocytoma cell line 12 (PC12) cells in an astrocyte-rich environment. MAIN METHODS: The abilities of AP1 and AP2 to reduce the secretion of pro-inflammatory cytokines Interleukin (IL)-1, IL-6, and Tumor necrosis factor (TNF)-α from stimulated astrocytes were tested. In addition, the abilities of AP1 and AP2 to reduce oxidative stress in astrocytes were tested using an oxidative-sensitive fluorescent dye. The reduction of chondroitin sulfate proteoglycan (CSPG) in stimulated astrocytes was tested using the dot blot method. Reduction of H(2)O(2)-induced death was tested in PC12 cells. Astrocyte-conditioned medium (ACM) and TNF-α-stimulated astrocyte-conditioned medium (SACM) were used to assess the effects of AP2 on PC12 cells treated with H(2)O(2). KEY FINDINGS: AP1 and AP2 reduced pro-inflammatory cytokines, reactive oxygen species (ROS), and CSPG in TNF-α stimulated astrocytes. AP1 protected H(2)O(2)-treated PC12 cells cultured in ACM. Co-incubation of PC12 cells in H(2)O(2), and ACM collected from AP1 treated astrocytes did not prevent cell death. SIGNIFICANCE: AP1 and AP2 effectively ameliorated astrocytic pro-inflammatory reactions and prevented PC12 cell death with different efficacies. These compounds may be candidates for treatment of spinal-cord injury and neurodegeneration.

Pain perception during miniplate-assisted orthodontic therapy.

Miniplate and screw devices are widely used for fracture repair and fixation of osteotomies. Currently, these miniplate systems are being used as orthodontic treatments for skeletal anchorage. However, despite the widespread use of these treatments, patients are apprehensive when they need to undergo miniplate procedures. Recently, we assessed pain perception using the visual analog scale (VAS) score (0-100 mm) in patients who had undergone miniplate procedures. Thirty miniplates were positioned in the maxilla as skeletal anchors for orthodontic treatment. On the first day after insertion of the fixed orthodontic appliances, the mean VAS score was 36.3 mm. The mean VAS score at 24 hours after insertion of the miniplate was 58 mm. Three months after orthodontic force was applied to the miniplate, the mean VAS scores during eating and speaking gradually decreased to 20 mm and 15 mm, respectively. The mean VAS score at 24 hours after removal of the miniplate was 41.3 mm. Three months after removal of the skeletal anchors, the VAS score decreased to 5 mm. Eighty-eight percent of patients stated that they would be prepared to undergo these new and more efficient treatment modalities in the future. The miniplate system was successfully used in this study as a skeletal anchor, and the patients could endure the pain and discomfort of this orthodontic treatment.