International Journal of Oral-Medical Sciences
Online ISSN : 2185-4254
Print ISSN : 1347-9733
ISSN-L : 1347-9733
Current issue
Displaying 1-6 of 6 articles from this issue
Original Articles
  • Aoi Yoshizawa, Kaori Ishii, Toshio Wani, Haruka Koyama, Yui Fujiwara ...
    2024 Volume 23 Issue 1 Pages 1-8
    Published: September 21, 2024
    Released on J-STAGE: September 21, 2024
    JOURNAL FREE ACCESS

    In modern orthodontics treatment, mix dentition patients who have narrow maxillary dental arch width are treated by lateral expansion treatment of dental arch. Maxillary lateral expansion treatment can increase the width diameter of the dental arch and palatal width diameter. However, changes in the morphology of the palatal basal region due to expansion treatment have not been evaluated. First, we carried out an investigation of long-term growth changes in palatal morphology in the general Japanese population. Additionally, in the patients who were treated by expansion, we compared the effects of expansion with different types of expansion devices. Longitudinal records(34 study casts, 6 to 12 years of age)were classified according to growth stage(T1: early mixed dentition, T2: middle mixed dentition, and T3: late mixed dentition or permanent dentition). A line drawn perpendicularly from the reference plane to the palatal basal region was divided into 10 sections, and the palatal width was measured in each region. Palatal widths were set at deep area(DA), middle area(MA), and shallow area(SA). Comparison of the palatal width(three regions)between Rapid maxillary expansion (RME N=15)and Slow maxillary expansion(SME N=15)were evaluated same methods as above. DA and the Palatal depth were significantly smaller at T1 than T2 and at T2 than T3, respectively(both p <0.05). The SA changed significantly less from T2 to T3 than did the DA(p <0.01). Although, in DA, expansion amount was significant difference between RME and SME, there were not significant difference in SA. The growth amount of palatal width was different between the DA and the SA. RME was expanded greater in DA than SME.

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  • Yasuyo Koide
    2024 Volume 23 Issue 1 Pages 9-17
    Published: September 21, 2024
    Released on J-STAGE: September 21, 2024
    JOURNAL FREE ACCESS

    This study explores factors influencing the onset of sleep bruxism(SB)and optimal measurement periods using electromyogram(EMG)recordings over 28 consecutive nights in self-reported dental professionals with bruxism. Seven dentist bruxers(three males, four females, mean age 30.0±3.5, range: 29-33)were recruited. Ultraminiature wearable EMG devices(EMG Logger, GC Co., Ltd. Tokyo, Japan)recorded masseteric activity during sleep. EMG data were processed using default software(W-EMG viewer, GC Co., Ltd. Tokyo, Japan). The analysis calculated the total number of SB episodes per night divided by total sleep time. Episodes were counted over 28 nights, and detection rates were computed for two to eight consecutive nights. Regression analysis identified SB-related factors, with headache in the temple area, joint noise, fatigue, and stress as independent variables. Optimal measurement periods were explored by comparing detection rates between consecutive nights using one-way ANOVA, followed by Bonferroni-adjusted multiple comparisons. A significant increase in detection rates occurred between one night and consecutive nights 3 to 8. No significant differences existed between one and two consecutive nights. Subgroup analysis revealed a significantly lower detection rate for those without temple area headaches when the EMG logger was used for one or two consecutive nights. Recommendations include a minimum of four days of EMG wear for subjects without temple area headaches, adjusting based on pre-interview assessments of symptoms. This study provides insights into SB detection, emphasizing the need for tailored measurement periods, and highlights the significance of temple area headaches in predicting SB onset.

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  • Megumi Fuse, Takao Kuwada-Kusunose, Akihiro Ogura
    2024 Volume 23 Issue 1 Pages 18-25
    Published: September 21, 2024
    Released on J-STAGE: September 21, 2024
    JOURNAL FREE ACCESS

    The advancement of bioactive scaffolds for tissue regeneration stands as a fruitful domain within polymer chemistry. Particularly in dentistry, scaffolding materials play a vital role in treating periodontal diseases and facilitating implant treatments for regenerating the maxillomandibular complex. In this research, we engineered a poly(lactic acid)(PLA)film, a biodegradable polymer, with enhanced physiological activity. The PLA film underwent hydrolysis through KOH treatment to modify its surface. The weight loss of PLA-KOH in phosphate-buffered saline solution(PBS, pH = 7.4)was assessed in comparison to pure PLA. Significantly, PLA-KOH exhibited a higher weight loss than PLA, with values of 4.8% and 3.1%, respectively, after 91 days of immersion(p < 0.05). The introduction of carboxylic acid was achieved through 0.5M KOH hydrolysis, and the precipitation of apatite on the PLA film was confirmed after immersion in Hanksʼ Balanced Salt Solution(HBSS, pH 7.4)without organic species for 1, 3, 7, 14, 21, and 28 days at 37℃. Scanning electron microscopy illustrated faster and larger precipitation on the PLA-KOH film compared to PLA after 28 days of HBSS immersion. The formation of hydroxyapatite on both PLA and PLA-KOH films following HBSS immersion was substantiated by X-ray diffraction(XRD). This HBSS immersion experiment effectively demonstrated the bioactivity of both PLA and PLA-KOH.

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  • Hideki Takai, Naomi Igarashi, Yorimasa Ogata
    2024 Volume 23 Issue 1 Pages 26-32
    Published: September 21, 2024
    Released on J-STAGE: September 21, 2024
    JOURNAL FREE ACCESS

    Leucine-rich α2 glycoprotein(LRG), C-reactive protein(CRP)and heat shock proteins (HSPs)are inflammation-related proteins which accurately reflect disease activities and degree of tissue damage. Tumor necrosis factor-α(TNF-α), interleukin-6(I L -6)and in terleukin-1β(IL-1β)are typical inflammatory cytokines that increase in periodontitis. Junctional epithelium (JE)lies immediately apical to the base of the pocket, and attaches to the enamel surface with hemidesmosomes. To analyze changes in the expressions of LRG, CRP and HSP70 mRNA and protein in inflamed periodontitis tissues, especially in the JE, human gingival epithelial Ca9-22 cells were treated with TNF-α(10 ng/ml), IL-6(10 ng/ml)or IL-1β(1 ng/ml)to induce an inflammatory state. Total protein and RNA were extracted, and Western blot and real-time PCR were performed. Cytotoxic lactate dehydrogenase(LDH)assays were used to analyze the cytotoxicity of TNF-α, IL-6 or IL-1β on Ca9-22 cells. Cytotoxicity was detected for TNF-α, IL-6 and IL-1β a t 12 h, with the highest cytotoxicity at 24 h. IL-1β decreased LRG and HSP70 mRNA and protein levels at 12 h and 24 h. TNF-α increased LRG mRNA and protein levels at 12 h and suppressed HSP70 mRNA and protein levels at 24 h. IL-6 increased LRG mRNA and protein levels at 12 h and decreased HSP70 mRNA and protein levels at 12 h. These results suggest that TNF-α and IL-6 could be involved in the onset and progression of periodontitis by regulating the expression levels of LRG and HSP70 in the JE.

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  • Kaori Ishii, Yui Fujiwara, Shinichi Negishi
    2024 Volume 23 Issue 1 Pages 33-37
    Published: September 21, 2024
    Released on J-STAGE: September 21, 2024
    JOURNAL FREE ACCESS

    This study aimed to investigate the relationship between facial morphology and oral function among schoolchildren, utilizing measurements such as the facial index, tongue raising force, occlusal force, and lip closure force within a general population. A total of 143 third- and fourth-grade elementary school students(77 boys and 66 girls)participated in the study. The facial index(posterior facial height/anterior facial height)was computed from photographs of the right side of each participant’s face. Among the subjects, those with a facial index falling below or exceeding 1 S.D. from the mean were categorized as long-faced(12 boys, 12 girls)or short-faced(15 boys, 10 girls), respectively. Oral function tests were conducted by measuring tongue raising force, occlusal force, and lip closure force three times each, and the mean values were calculated. Comparison between long-faced and short-faced subjects revealed a significant discrepancy in occlusal force among boys and girls, with short-faced subjects exhibiting greater values compared to the long-faced subjects. While girls exhibited similar tendency as boys in terms of occlusal force, no significant differences were found across all parameters. Correlation analysis unveiled significant positive correlations between the facial index and occlusal force, occlusal force and tongue raising force, and tongue raising force and lip closure force. In conclusion, a significant correlation was identified between occlusal force and vertical facial morphology. Long-faced individuals tended to demonstrate weaker occlusal force, while short faced individuals exhibited stronger occlusal force.

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  • Yohei Nakayama, Yorimasa Ogata
    2024 Volume 23 Issue 1 Pages 38-50
    Published: September 21, 2024
    Released on J-STAGE: September 21, 2024
    JOURNAL FREE ACCESS

    We have previously developed a novel assessment for wound healing, called the modified early wound-healing index(mEHI), following a modified papilla-preservation technique(mPPT). The previous study showed better scores of mEHI in enamel matrix derivative group than those of recombinant human fibroblast growth factor group. However, the inter-rater reliability of the mEHI were not high. This study aimed to investigate the causes of low inter-rater reliabilities in mEHI by analyzing differences in the intraclass correlation coefficients(ICCs)between dental board-certified doctors (BDs)and non-board-certified doctors(non-BDs)of the Japanese Society of Periodontology. A total of 79 wound-healing sites following mPPT was evaluated using the mEHI by eight BDs and 12 non-BDs. The mEHI included incision, fibrin clot, step, redness, swelling, and dehiscence. The mEHI scores and the ICCs were compared between the BD and non-BD groups. Partial ICCs between the mEHI items were calculated, and the differences were statistically analyzed. The ICCs of fibrin clot, step, and redness were >0.45, and the incision line and step had low ICCs in both groups. The scores of fibrin clot and dehiscence were higher in the non-BD group than in the BD group. A significant negative partial correlation was noted between the incision line and fibrin clot, and between dehiscence and swelling in the non-BD group. In conclusion, the mEHI is a valuable tool in evaluating wound healing. However, assessments of fibrin clot and dehiscence were found to be influenced by periodontal treatment experience, contributing to the low inter-rater reliability of the mEHI.

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