日本歯科保存学雑誌
Online ISSN : 2188-0808
Print ISSN : 0387-2343
ISSN-L : 0387-2343
49 巻 , 6 号
選択された号の論文の20件中1~20を表示しています
総説
ミニレビュー
原著
  • 礪波 健一, 小沼 正樹, 新田 浩, 荒木 孝二, 俣木 志朗, 黒崎 紀正
    原稿種別: 原著
    2006 年 49 巻 6 号 p. 725-730
    発行日: 2006/12/31
    公開日: 2018/03/31
    ジャーナル フリー
    The importance of diagnosing caries during the early stage has been increasingly recognized along with the increasing prevalence of the concept of minimal intervention in dentistry. However, conventional diagnostic systems are not necessarily adequate for this purpose, and the diagnosis of caries needs to be improved. The air of this study was to elucidate the relation between the property values of images of pit-and-fissure discoloration and conventional caries diagnosis. The possibility of caries diagnosis using discoloration imaging was also investigated. Fifteen molars with pit-and-fissure discoloration were used in this experiment. The occlusal surface of each tooth was photographed with a digital camera and the degree of discoloration was examined. The fractal dimension, the area in proportion to the whole occlusal surface and the formfactor of the discoloration were calculated using image analysis software. Each tooth was also examined with a DIAGNOdent® system and was conventionally diagnosed using clinical procedured, according to the caries depth. The relationships between fractal dimension, area proportion, formfactor, DIAGNOdent value and the clinical diagnosis were analyzed statistically. The fractal dimension, the area proportion, and the DIAGNOdent value tended to increase with the depth of the caries: Spearman's correlation coefficients between the clinical diagnosis and fractal dimension, the area proportion, and the DIAGNOdent value were 0.867, 0.862 and 0.724, respectively (p<0.01 for all comparisons). Significant correlations were also indicated between the fractal dimension and the area proportion, the fractal dimension and the DIAGNOdent value, and the area proportion and the DIAGNOdent value; Pearson's correlation coefficients were 0.874, 0.771 and 0.714, respectively (p<0.01). On the other hand, the formfactor was found to be independent of the caries depth. These results indicated that image analysis of molar pit-and-fissure discoloration would be useful for caries diagnosis.
  • 曽我 賢彦, 岩本 義博, 谷本 一郎, 浅田 薫, 横井 彩, 目黒 道生, 工藤 値英子, 吉澤 さゆり, 山部 こころ, 外山 裕, ...
    原稿種別: 原著
    2006 年 49 巻 6 号 p. 731-738
    発行日: 2006/12/31
    公開日: 2018/03/31
    ジャーナル フリー
    Infection is a critical issue in immuno-compromised patients such as with hematologic malignancies. Oral infection is no exception. Among various oral infectious diseases, periodontitis is one of the most common diseases. However, currently, very few hospitals are undertaking intensive interventions by dentists. In many other hospitals, physicians themselves must control infections, including those of oral origin. Detailed periodontal examination is almost impossible for physicians. Therefore, a simple blood test to screen for periodontal infection such as measuring antibody titer against periodontal pathogens would be a powerful tool for physicians. However, the question remains as to whether the antibody titers accurately reflect the degree of periodontitis in leukopenic patients, since both the quantity and quality of lymphocytes are greatly reduced in such patients. The aim of this study was to determine the relationship between the severity of periodontitis and serum immunoglobulin G (IgG) antibody titer against Porphyromonas gingivalis (Pg) in subjects with hematologic malignancies. A total of 122 patients receiving treatment for hematologic malignancies (M: 76, F: 46; age: 47.4±16.3y) and 150 systemically healthy subjects (M:58, F: 92; age: 43.1±18.1y) were enrolled in this study. Information on hematology of the patients was obtained from their physicians. All subjects were examined for periodontal conditions and serum IgG antibody titers against Pg FDC381 and SU63. Periodontal condition was evaluated by the Community Periodontal Index (CPI) which was scored by examining all existing teeth, and subjects were classified according to the maximum code. In each CPI, differences in the frequencies of subjects with high serum Pg IgG titer [>2 standard deviation (SD) of the mean of 20 control subjects] between the patient group and systemically healthy control group were compared. Patients with hematopoitic organ failure exhibited various white blood cell (WBC) counts. About 40% of the patients had WBC counts below 3,000 cells/μl,Severer CPI was associated with higher frequencies of the subjects with high serum Pg IgG antibody titer in both the patient groups and systemically healthy control group. In the same CPI, there were no significant differences in the frequencies of subjects with high antibody titer between the two groups. Based on these results, it is suggested that serum Pg IgG antibody titer is applicable to screen for periodontal infection in patients with hematologic malignancy even with reduced WBC counts.
  • 山口 人巳, 久保田 健彦, 川崎 健司, 両角 俊哉, 板垣 真奈美, 吉江 弘正
    原稿種別: 原著
    2006 年 49 巻 6 号 p. 739-748
    発行日: 2006/12/31
    公開日: 2018/03/31
    ジャーナル フリー
    Objective: The purpose of the present study was to determine the effect of chewint suger-free gums containing vegetable tannin on periodontal health. Materials and methods: Thirty generalized chronic periodontitis patients (53.8y±9.5) who signed an informed consent were recruited in this study. Using the double-blind study method, the subjects were grouped into three: 1) ten subjects chewing vegetable tannin gum without brushing; 2) ten subjects chewing placebo gum without brushing; and 3) ten brushing subjects without chewing gum. Before and after the 7-day experiment period, saliva was collected after 5 minutes of stimulation and then used for biochemical [lactic dehydrogenase (LDH), alkaline phosphatase (ALP) activities, active and latent matrix metalloproteinase (MMP)-8 and MMP=9] and microbiological measurements [Porphyromonas gingivalis, Prevotella intermedia and total bacterial amounts]. Also, individual clinical periodontal status was recorded including probing pocket depth (PPD), loss of attachment (LA), gingival index (GI), plaque control record (PCR) and bleeding on probing (BOP). Statistical analyses were performed with paired-t and Wilcoxon signed-ranks tests. Results: Only the brushing group had a significant decrease in PPD and PCR (p<0.01). The LA did not change in all groups. The GI and the BOP scores were significantly decreased at one week after the experiments, compared to the base-line (p<0.05, 0<0.01). The PCR score of the brushing group after the experiment period was lower than the base-line (p<0.01). The salivary ALP decreased significantly only in the tannin group (p<0.05). The other enzymes also showed a decreased tendenty, but did not reach significant levels. No active MMP-9 was detected in all patients There was also no difference in the bacterial findings among groups. Conclusion: The present study suggests that chewing suger-free gums containing vegetable tannin could have beneficial effects on periodontal health.
  • 松本 妃可, 吉嶺 嘉人, 赤峰 昭文
    原稿種別: 原著
    2006 年 49 巻 6 号 p. 749-754
    発行日: 2006/12/31
    公開日: 2018/03/31
    ジャーナル フリー
    The condition of lasering must be carefully controlled so as not to damage the periodontal tissues during laser irradiation in a root canal. The aim of this study was to investigate the temperature rise on root surfaces of an extracted human tooth during and after intracanal irradiation by Erbium: Yttrium-Aluminum: Garnet (Er: YAG) laser. A single-rooted extracted tooth was used. After the crown was removed, the root canal was enlarged mechanically up to a size of # 60. Er: YAG laser was irradiated using a cone-shaped fiber tip without water spray or air cooling at different conditions: pulse energy (30, 50 and 70 mJ), pulse per second (20 pps and 10 pps), draw-up speed from an apical foramen (2mm/sec and 1mm/sec), and number of irradiation times (1 and 2 times). Temperature changes were recorded thermographically. Thickness of the root canal walls was measured using a 3DX multi-image micro CT after irradiation. The increase of the temperature on root surfaces was higher at the thin root canal wall area, and highest at the apical area. The temperature rose higher with the second irradiation than with the first irradiation. When irradiated at the same energy, the temperature increased higher under the condition of 20 pps and 2 mm/sec compared to that of 10 pps and 1mm/sec. The results showed that the temperature rise was less than 5℃ at the following laser settings and considered harmless to periodontal tissues: 1) irradiating 2 times of 30 mJ or 1 time of 50 mJ with 20 pps and 2 mm/sec, and 2) irradiating 2 times of 30 mJ or 50 mJ with 10 pps and 1 mm/sec.
  • 金村 成智, 梅村 星子, 赤松 佑紀, 宮本 めぐみ, 雨宮 傑, 大迫 文重, 佐々木 充, 中西 哲, 林 誠司, 山本 俊郎
    原稿種別: 原著
    2006 年 49 巻 6 号 p. 755-761
    発行日: 2006/12/31
    公開日: 2018/03/31
    ジャーナル フリー
    Although serious systemic infectious diseases originating in local infectious foci can be caused by bone marrow control and immunosuppression in bone marrow transplantation (BMT) patients and renal transplantation (RT) patients, guidelines for the oral management of BMT and RT recipients have not been established. The subject population for this investigation consisted of 108 BMT patients and 109 RT patients who were referred to our clinic for oral examination during the 6 years from 1/1/2000 to 12/31/2005. In our clinic, all lesions are examined for active infectious lesions, subjective and objective symptoms are excluded by X-ray findings or are inactive infectious lesions, and expected inactive infectious lesions are assessed by intraoral and X-ray examination. Moreover, only active infectious lesions are treated and inactive lesions are observed, followed by guarded diagnosis by careful examination of lesions as to their active or inactive status. As a result, serious systemic or local infectious diseases are treated, except: a tooth with an apical lesion in which there are no other clinical symptoms, poor root canal with no other clinical symptoms, and an impacted tooth without clinical symptoms. It is important that mouth cleaning management and guidance are carried out before BMT and RT to prevent infection. Accordingly, these guidelines are presented for oral management and prevention of infection in both BMT and RT recipients.
  • 長野 孝俊, 山口 博康, 小林 一行, 渋川 直也, 白川 哲, 高瀬 俊彦, 五味 一博, 新井 高
    原稿種別: 原著
    2006 年 49 巻 6 号 p. 762-767
    発行日: 2006/12/31
    公開日: 2018/03/31
    ジャーナル フリー
    This study was carried out to examine the possibility of using alkali-ion water for root canal irrigation. The biocompatibility of alkali-ion water was tested by assessing its effect on mitogenic activity of cultured human pulp fibroblast cells. In addition, a cytotoxicity assay was also conducted using rat lymphocytes, which were more easily damaged than human pulp fibroblast cells. In addition, the organic material-dissolving capacity of alkali-ion water was evaluated. The numbers of living cells (rat lymphocytes and human pulp fibroblast cells) did not significantly differ between the control (physiological saline) group and the alkali-ion water group. Furthermore, cytotoxicity experiments showed no significant differences between the control and alkali-ion water groups. However, alkali-ion water showed significantly increased organic materialdissolving capacity compared with the control. These results indicate that the alkali-ion water is sufficiently safe and useful for clinical application of root canal treatment.
  • 瀧谷 佳晃, 関根 源太, 仲宗根 歩, 吉田 隆一, 関根 一郎
    原稿種別: 原著
    2006 年 49 巻 6 号 p. 768-772
    発行日: 2006/12/31
    公開日: 2018/03/31
    ジャーナル フリー
    It has been shown that unsuccessful root canal fillings influence the healing of periapical disease. Especially, in the case of over-extended root canal fillings, post-operative pain and inflammatory reactions of periapical tissue are observed. It is difficult to remove the over-extended gutta-percha safely and effectively by intra-canal procedures. In this report, gutta-percha over-extended into the periapical tissue of the root canal with excessively enlarged physiological foramen was removed by means of intra-canal instruments, K-files and barbed broaches. The barbed broaches used in this report weree adjusted short, and the gutta-percha was removed effectively. The findings after 1 year of the root canal treatment showed that local conditions were good and the roentgenologic findings were improved completely.
  • 白川 哲, 山口 博康, 長野 孝俊, 小林 一行, 金指 幹元, 五味 一博, 新井 高
    原稿種別: 原著
    2006 年 49 巻 6 号 p. 773-780
    発行日: 2006/12/31
    公開日: 2018/03/31
    ジャーナル フリー
    Lipopolysaccharide (LPS) from gram-negative bacteria has various activities and is a common inflammatory factor in endodontic-periodontal lesions. Also, endothelin is detected in both normal and inflammatory pulp tissues, but it has still not been shown howendothelin is concerned with inflammation. The differences between the influences of LPS and endothelin on pulp tissues have also not yet been examined. The aim of this study was to reveal how LPS and endothelin influence human dental pulp cells (HDPC). We compared the biological activities between LPS and endothelin using cell proliferation, alkaline phosphatase (ALP) activity and the gene expressions of interleukin-6 (IL-6), cyclooxygenase-2 (COX-2) and heat shock protein (HSP), which is a stress protein. The cell proliferation of HDPC in endothelin was significantly higher than that in the control. However, cell proliferation of HDPC in LPS tended to increase. The Alp activity of HDPC was suppressed in endothelin, but the suppression of ALP activity in LPS was greater than that of ALP activity in endothelin. The mRNA expressions of HSP60 and HSP70 were not different between the control, LPS and endothelin. While the mRNA expression of IL-6 was induced by endothelin, the mRNA expression of IL-6 was more induced by LPS than by endothelin. Also, the mRNA expressions of HSP27 and COX-2 were induced in the control and endothelin. However, the mRNA expressions of HSP27 and COX-2 were more induced in LPS than that in the control and endothelin. In conclusion, it has been shown that the biological activities between LPS and endothelin are different, and that LPS and endothelin do not influence the cytodifferentiation of HDPC.
  • 千枝 佳子, 石井 信之, 南田 厳司, 齋藤 大輔, 小泉 忠彦, 寺中 敏夫
    原稿種別: 原著
    2006 年 49 巻 6 号 p. 781-788
    発行日: 2006/12/31
    公開日: 2018/03/31
    ジャーナル フリー
    Parathyroid gland deficiency is thought to contribute to the progression of periapical lesions, and alveolar bone destruction is associated with enhanced osteoclast activity. Parathyroid hormone (PTH) and calcitonin (CT) deficiency induced greater enlargement of alveolar bone destruction in periapical lesion in our study. The purpose of the present study was to investigate the relationship between osteoclast appearance and deficiency of PTH and CT in periapical bone destruction, Sixty 10-week-old female Wistar rats were divided into 22 parathyroidectomized (P-ect) rats, 22 parathyroidectomized and thyroidectomized (T & P-ect) rats and 16 non-ectomized (Control) rats. All experimental and control rats received a treatment of pulp exposure in both mandibular first molars, and all experimental samples were obtained at 1 and 3 weeks after treatment. Serial sections were cut and stained with hematoxylin and eosin for general histological finding. Appearance of osteoclast was identified by TRAP staining, and the number of osteoclasts was measured. It was found that periopical lesions of each experimental group (P-ect group and T & P-ect group) were characterized by the presence of abscess infiltrated by PMNs and macrophages after 1 and 3 weeks, and significant differences from the control groups were not found. The number of osteoclasts lining lesions was quantified at each time point. The osteoclast infiltration in the periapical lesion area was significantly different between the control group (21.1±11.1 cells) and P-ect experimental group (35.0±6.5 cells) after 1 week. The appearance of osteoclasts in the P-ect (42.0±11.7 cells) group and T & P-ect experimental group (37.3±20.0 cells) was compared with the control group (23.0±15.5 cells), and the significant difference increased by 3 weeks. The results showed an increase of osteoclast and periapical bone destruction in the P-ect and T & P-ect rats. The parathyroid and thyroid gland deficiency inducted the development of osteoclast, causing the periapical bone to increase.
  • 鈴木 丈一郎, 長野 孝俊, 湯浅 茂平, 渡辺 一郎, 五味 一博, 新井 高
    原稿種別: 原著
    2006 年 49 巻 6 号 p. 789-796
    発行日: 2006/12/31
    公開日: 2018/03/31
    ジャーナル フリー
    Purpose: Plaque control is most important for the prevention and treatment of periodontal disease and SPT. This time, clinical effects of a newly developed mouth rinse (MMX-3) on the control of plaque accumulation and the prevention of gingivitis were examined. Materials & Methods: A total of 60 subjects who were office workers in a medicine manufacturing company were enrolled in this study. For a period of 4 months, the subjects in the test group rinsed with MMX-3 and those in the control group rinsed with only the basis material of MMX-3 and the commercia group rinsed with Listerine™. All subject continued their normal home oral hygiene practices and used mouse rinses twice or three times a day. Subjects underwent identical examination to determine their plaque index and gingival index. Results: There were significant differences (p<0.05) in plaque index and gingival index between the test and control groups. However, there was no significant difference in plaque index or gingival index between the test and commercial rinse groups. The results suggested that the newly developed mouth rinse was useful for the control of plaque accumulation and the prevention of gingivitis. The mouth rinse has the same effects on the control of plaque accumulation and the prevention of gingivitis compared with a commercial rinse (Listerine™).
  • 大島 崇史, 宮田 博史, 大島 光宏, 山口 洋子, 古豊 育太朗, 小木曽 文内, 大塚 吉兵衛, 伊藤 公一
    原稿種別: 原著
    2006 年 49 巻 6 号 p. 797-809
    発行日: 2006/12/31
    公開日: 2018/03/31
    ジャーナル フリー
    It is reported that dental cysts contain interleukin-1 (IL-1), which stimulates protaglandin secretion by fibrous capsule-derived fibroblasts. However, the mechanism of dental cyst expansion in alveolar bone remains unclear. The aim of this study was to simulate the autocrine effects of prostaglandin E2 (PGE2) on a growth factor for epithelial cells (hepatocyte growth factor, HGF), a bone resorbing cytokine (interleukin-6, IL-6), and PGE2 production by human radicular cyst- and odontogenic keratocyst-derived fibroblast-like cells (RC cells and KC cells) in vitro. The confluent RC cells and KC cells and KC cells were exposed to 0.1 μmol/l of PGE2 in serum-free DMEM for 0, 1, 3, 6, or 24 hours. The medium was harvested after 1, 3, 6, or 24 hours of each stimulation period. ELISA kits were employed to determine the amount of HGF, IL-6 and PGE2 in the supernatant, respectively. PGE2 significantly stimulated IL-6 production by RC cells and KC cells, and the effective stimulation time was 1 to 3 hours. PGE2 stimulation also induced HGF production; however, the most effective stimulation time was 24 hours. Furthermore, PGE2 stimulated PGE2 production itself in the RC cells and KC cells, and every stimulation period was effective. These results show that PGE2 stimulates HGF, IL-6 and PGE2 production by RD cells and KC cells, suggesting that autocrine PGE2 may induce radicular cyst and odontogenic keratocyst expansion once PGE2 is produced in the cyst fibrous capsule.
  • 齋藤 次雄, 前田 宗宏, 勝海 一郎
    原稿種別: 原著
    2006 年 49 巻 6 号 p. 810-821
    発行日: 2006/12/31
    公開日: 2018/03/31
    ジャーナル フリー
    Nickel-titanium orifice openers were designed to prepare the coronal and middle third of the canal. Three different types of rotary nickel-titanium endodontic instruments, QuantecFlare® K3 OrificeOpener® and Tac Endo Flare®, were selected for investigation. In order to investigate the effects of the nickel-titanium instrument type, the insertion speed during cutting, and the use of sodium hypochlorite during cutting, we continuously measured the torque at the enlargement of the root canal orifice using a specially designed computer-controlled torque testing device. Cutting instruments were directly immersed in a plastic dish containing 10% sodium hypochlorite solution or 10% sodium hypochlorite paste for 60 minutes, and rinsed under running distilled water. The rotational speed was fixed at 300 rpm. Instruments were then inserted to a depth of 8 mm into standardized models of the resin straight root canal model with different insertion speeds (0.01 mm/sec and 0.05 mm/sec). The cutting efficacy was analyzed based on the torque-insertion distance and the calculation of the variation in torque (ΔT). Morphological observations of the cross-sectional profiles were also conducted. The following conclusions were obtained: 1. The three types of instruments had different cross sections. This suggests the possibility that the blade structure affects cutting. 2. The integral value ΔT of the cutting torque and insertion distance are affected by the type of cutting instrument and decreased significantly in the order of Tac Endo Flare®, K3 OrificeOpener® and Quantec Flare®. 3. ΔT was affected by the insertion speed and was significantly greater for an insertion speed of 0.05 mm/sec than for 0.01 mm/sec. 4. ΔT tended to decrease in the order of the nonimmersed group, the sodium hypochlorite solution gorup and the sodium hypochlorite paste group.
  • 貴美島 哲, 相原 英信, 柵木 寿男, 奈良 陽一郎
    原稿種別: 原著
    2006 年 49 巻 6 号 p. 822-830
    発行日: 2006/12/31
    公開日: 2018/03/31
    ジャーナル フリー
    The current adhesive system is becoming more simple and easier, while in vitro bond strength to tooth substance is becoming better as new products appear. However, the in vitro data or values are usually obtained from sound ground and flattened tooth substance. Clinically, a tooth (i.e. adherent) which needs a restoration is usually diseased or in infirm condition, and has some sort of depression or cavity. The purpose of this study was to measure the microtensile bond strength of a one-bottle resin adhesive system (Clearfil Tri-S Bond: Kuraray Medical) to cariesaffected dentine, which lies in a class 1 cavity floor. Furthermore, the relationship between the value of DIAGNOdent™(KaVo) of adherent dentine and bond strength was also examied. ・The mean micro-tensile bond strength to cariesaffected dentine (CD)/sound dentine (SD) in MPa (±s.d.) was 5.86±1.96/14.77±3.30, and CD was significantly lower than SD (p<0.01). With the one-step adhesive, it was difficult to gain a high bond strength to caries-affected dentine. ・The correlation coefficient of the bond strengths and DIAGNOdent^<TM> values of CD/SD was 0.0659/0.2080. In both cases, there was no correlation between the bond strength and DIAGNOdent^<TM> value. The DIAGNOdent™ value of CD was significantly higher than that of SD. ・Regardless of the type of dentine, it seemed difficult to anticipate the level of micro-tensile bond strength from the value of DIAGNOdent™
  • 池島 巌, 原田 千鶴子, 桃井 保子
    原稿種別: 原著
    2006 年 49 巻 6 号 p. 831-835
    発行日: 2006/12/31
    公開日: 2018/03/31
    ジャーナル フリー
    Objective: It is well known that tooth color changes under various conditions such as drying and lighting. Chinically, there are some problems with color differences of resin and teeth after resin filling. The purpose of this study was to analyze tooth color changes under the condition of drying. Materials and Methods: Six healthy incisors of maxillae from two men and four women were used for this study. The changes of tooth color were measured every 30 seconds using a spectrum color meter (SE-2000, Nippon Denshoku) under the rubber dam dry field technique. Results: The value of Δa* did not differ during the experimental period, the value of ΔL* increased and the value of Δb* decreased time-dependently. The ΔE*ab value was increased by drying. On the other hand, these color changes were induced in the early stage of drying. Conclusions: The result of the ΔL* value indicated that the white level of teeth increases after drying. The change of Δb* means that the yellow level of teeth decreases after drying. These findings suggest that it is suitable to measure the teeth color before resin filling.
  • 野口 晴加, 坂上 竜資, 永井 淳
    原稿種別: 原著
    2006 年 49 巻 6 号 p. 836-845
    発行日: 2006/12/31
    公開日: 2018/03/31
    ジャーナル フリー
    In this study, immunohistological observations were performed using two kinds of epithelial markers to determine the maintainability of the original characteristics after free gingival graft procedures. Matertais and Methods: One hundred and twenty male Wistar rats were used. After the free gingival graft procedures, the animals were sacrificed 1, 2, 4, and 6 weeks postoperatively. Conventional histological sections were made. Involucrin and Cytokeratin 10 were used for the immunohistochemical analysis. Antibody positive rate within the epithelial layer was calculated. Results: Stainability against Involucrin and Cytokeratin 10 did not change until 6 weeks postoperatively, and the grafted site showed the similar stainability as in the palate. The percentage of positive cell rate after 6 weeks postoperatively was close to that of the palate. Discussion: The histological as well as immunohistochemical characteristics of palatal keratinization were maintained after the free gingival procedures.
  • 勝海 一郎, 山崎 孝子, 都築 民幸, 北村 和夫, 石井 隆資, 前田 宗宏, 小倉 陽子, 好士 連太郎, 阿川 透久, 宮里 尚幸, ...
    原稿種別: 原著
    2006 年 49 巻 6 号 p. 846-853
    発行日: 2006/12/31
    公開日: 2018/03/31
    ジャーナル フリー
    On 6 types of Ni-Ti spreader (Roeko NiTi # 15; Roeko NiTi # 25; Roeko NiTi # 35; Roeko NiTi D11T; Brasseler Naviflex NT D11T; Brasseler Naviflex NT 4SP), dimensions were measured under digital microscope, and a load application test was performed in the axial direction of the spreader. The results were as follows: 1. In Roeko NiTi # 15, D3 was 0.38 mm, D16 was 0.61 mm, taper was 0.018, and tip angle was 28.9°. Similarly, the above values were 0.32 mm, 0.68 mm, 0.027, and 28.0° respectively in Roeko NiTi # 25. The values were 0.50 mm, 0.70 mm, 0.016, and 32.5° respectively in Roeko NiTi # 35, and the values were 0.37 mm, 0.88 mm, 0.039, and 10.6° respectively in Roeko NiTi D11T. The values were 0.27 mm, 0.77 mm, 0.038, and 29.9° respectively in Brasseler Naviflex NT D11T, and 0.30 mm, 1.06 mm, 0.059, and 35.9° respectively in Brasseler Naviflex NT 4SP. 2. When a load was applied in the axial direction of the spreader, the load was 0.56 kgf in case the portion of 16 mm in length from the tip in Roeko NiTi # 15 was bent at a stroke. When the portion of 5 mm in length from the tip was fixed and the portion of 11 mm in length from the tip was bent at a stroke, the load was 4.32 kgf. The above values were 1.13 kgf and 7.52 kgf respectively in Roeko NiTi # 25, 1.24 kgf and 8.58 kgf in Roeko NiTi # 35, 0.82 kgf and 10.28 kgf in Roeko NiTi D11T, 0.63 kgf and 7.27 kgf in Brasseler Naviflex NT D11t, and 1.02 kgf and 17.61 kgf in Brasseler Naviflex NT 4SP. 3. The Ni-Ti spreader has super-elasticity and is flexible. Thus, it is difficult to apply pressure on it in the axial direction, during lateral condensation. However, this study revealed that sudden bending may be avoided if at least the tip portion of 5 mm in length from the tip is inserted into the root canal.
feedback
Top