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조선대학교 치의학연구원> Oral Biology Research (OBR)> Repetitive prestretching decreases hysteresis and abrupt force drops during the initial unloading phase of orthodontic elastomeric chains

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Repetitive prestretching decreases hysteresis and abrupt force drops during the initial unloading phase of orthodontic elastomeric chains

Jae-chan Jung , Sung-hoon Lim , Seo-rin Jeong
  • : 조선대학교 치의학연구원
  • : Oral Biology Research (OBR) 46권2호
  • : 연속간행물
  • : 2022년 06월
  • : 71-77(7pages)
Oral Biology Research (OBR)

DOI


목차

Introduction
Materials and Methods
Results
Discussion
Funding
Conflicts of Interest
ORCID
References

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초록 보기

This study evaluated the effect of repetitive prestretching on hysteresis and abrupt force drops during the initial unloading phase (1-mm-unloading/peak force ratio) of elastomeric chains. Thirty samples of closed-type elastomeric chains were tested for each group of generation II power chain, energy chain, and memory chain. Elastomeric chains were elongated to a 100% extension from their original length of 12.5 mm and unloaded. Forces during the five loading and unloading cycles were determined. The memory chain showed significantly lower hysteresis than the generation II power chain and energy chain. Both loading and unloading forces were decreased significantly with repetitive prestretching. However, unloading forces decreased less than the loading force, thereby reducing the hysteresis. All three products showed the greatest hysteresis in the first cycle, which decreased significantly following repeated prestretching. The 1-mm-unload/peak ratio increased significantly until the 4th cycle, the cycle after triple prestretching. Conclusively, repetitive prestretching of elastomeric chains further decreased hysteresis and abrupt force drop during the initial 1-mm unloading, up to triple prestretching.

UCI(KEPA)

간행물정보

  • : 의약학분야  > 기초치의학
  • : KCI등재
  • :
  • : 계간
  • : 2508-2558
  • : 2508-2566
  • : 학술지
  • : 연속간행물
  • : 1978-2022
  • : 1493


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This study aimed to investigate the antioxidant and anticancer activities of the fermented extract of the dried pericarp of Camellia japonica L. (CJ). The antioxidant activity of the extract after fermentation by Aspergillus oryzae (A. oryzae) at different doses, times, and temperatures was slightly decreased compared with that of the unfermented extract. The total polyphenol content decreased significantly as fermentation time was increased at 30℃, but there was no significant change when the fermentation was performed for 72 hr at different temperatures. The total flavonoid content was not significantly changed by fermentation conditions. Evaluation of the anticancer activity of the A. oryzae-fermented extract revealed that there was no effect on the viability of immortalized 293T cells treated with the extract for 48 hr, but the viability of YD-8 and YD-10B oral cancer cells was significantly reduced. In addition, there was a significant increase in the expression of cleaved PARP and caspase 3, and in apoptotic (annexin V/PI-stained) cells. These results suggest that the water extract of dried pericarp of CJ has no anticancer activity, but gained anticancer activity following fermentation by A. oryzae; furthermore, the fermented extract may be a potential treatment for oral cancer.

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This study aimed to compare the vertical and horizontal bone augmentation achieved when using different types of titanium mesh (Ti-mesh) on edentulous atrophic maxilla. Surgical intervention was performed in the maxillary molar area of three patients. One patient received A type Ti-mesh (aTM; pore size: 0.9 mm, thickness: 0.1 mm), and placement of one implant was carried out after 6 months. The remaining two patients received B type Ti-mesh (bTM; pore size: 1.7 mm, 3.37 mm; thickness: 0.3 mm;), and 4 implants were placed after 6 months. The findings showed that both types of Ti-mesh were associated with good feasibility and predictability with regard to vertical and horizontal bone augmentation. Pore size did not affect the amount of bone regenerated for implant placement. However, bTM was associated with several advantages, including decreased operation time and increased convenience during guided bone regeneration surgery.

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This case report presents the 8-year follow-up result of autotransplantation on a healed alveolar ridge, with sinus elevation and autogenous bone grafting. We present a case of a 30-year-old male patient whose maxillary first molar was extracted 1 year ago. Under general anesthesia, after the membrane of the left maxillary sinus was elevated, an artificial socket was prepared on the healed alveolar ridge of the left maxillary first molar area. The left maxillary third molar was extracted and tried on the prepared artificial socket. The autogenous bone was harvested and grafted to the left maxillary sinus floor. The transplanted tooth received root canal therapy 2 months after surgery. During the 8-year follow-up period, no discomforts, periodontal ligament (PDL) widening, or root resorption signs were observed. Desirable bone remodeling signs and regeneration of PDL were observed on the radiograph. Therefore, autotransplantation can be a treatment option for healed and deficient alveolar ridge.

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KCI등재

3Repetitive prestretching decreases hysteresis and abrupt force drops during the initial unloading phase of orthodontic elastomeric chains

저자 : Jae-chan Jung , Sung-hoon Lim , Seo-rin Jeong

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This study evaluated the effect of repetitive prestretching on hysteresis and abrupt force drops during the initial unloading phase (1-mm-unloading/peak force ratio) of elastomeric chains. Thirty samples of closed-type elastomeric chains were tested for each group of generation II power chain, energy chain, and memory chain. Elastomeric chains were elongated to a 100% extension from their original length of 12.5 mm and unloaded. Forces during the five loading and unloading cycles were determined. The memory chain showed significantly lower hysteresis than the generation II power chain and energy chain. Both loading and unloading forces were decreased significantly with repetitive prestretching. However, unloading forces decreased less than the loading force, thereby reducing the hysteresis. All three products showed the greatest hysteresis in the first cycle, which decreased significantly following repeated prestretching. The 1-mm-unload/peak ratio increased significantly until the 4th cycle, the cycle after triple prestretching. Conclusively, repetitive prestretching of elastomeric chains further decreased hysteresis and abrupt force drop during the initial 1-mm unloading, up to triple prestretching.

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4Effect of implant fixtures with blood pocket designed platforms on crestal bone

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The purpose of this study was to investigate the impact of an implant with a blood pocket designed platform on the crestal bone by analyzing the stress distribution upon simulated application of occlusal forces and assessing its clinical role in marginal bone loss surrounding the implant. Stress exerted on the cortical and cancellous bones of three different platform type implants (URIS, TSIII, and Astra EV) were analyzed using finite element analysis (FEA). A load of 150 N was applied at 0°, 45°, and 90° angles to the long axis of each implant, and marginal bone loss in the implanted URIS fixtures (blood pocket designed platform) after immediate and delayed loading was measured. FEA showed that the stress generated on the fixture upon loading of the URIS implant was lower than that of the other two implants. The URIS implant also exerted the lowest stress on the cortical bone upon application of vertical pressure at an angle of 0° to the long axis of the fixture. The mean marginal bone loss in the alveolar bone was 1.01±0.33 mm and 0.46±0.30 mm upon immediate and delayed loading, respectively. FEA also indicated that implants with blood pocket designed platforms exhibited better stress distribution in the implant fixture and cortical bone under vertical pressure when compared to the fixtures of other designs. The marginal bone loss observed one year after loading of the URIS implant in the current study was lower than that reported previously.

KCI등재

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KCI등재

6Full mouth rehabilitation of patient with decreased occlusal vertical dimension due to severely worn dentition and posterior bite collapse

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Pathologically progressive dental wear can cause dentin damage and pulp disease; it can even lead to tooth loss. The patient described herein, a 60-year-old male, had a decrease in vertical dimension due to severe abrasion of his remaining teeth and loss of his posterior teeth. The pattern of wear and its causes were evaluated, after which an appropriate vertical dimension and a repeatable centric relation position were considered. A full-mouth rehabilitation by increasing the vertical dimension was planned for the patient. His posterior bite support, wear history, facial features, interocclusal distance, and pronunciation were evaluated to determine the appropriate intermaxillary relationship and vertical elevation. Afterwards, full-mouth rehabilitation was completed using a monolithic zirconia prosthesis. The patient adapted well to the increased vertical dimension and the final prosthesis, had no complaints, and was aesthetically satisfied.

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