Journal of Oral Science
Online ISSN : 1880-4926
Print ISSN : 1343-4934
Volume 59 , Issue 4
December
Showing 1-24 articles out of 24 articles from the selected issue
Review
  • Domenica Matranga, Federico Matera, Giuseppe Pizzo
    2017 Volume 59 Issue 4 Pages 461-468
    Published: 2017
    Released: December 27, 2017
    [Advance publication] Released: August 31, 2017
    JOURNALS FREE ACCESS

    The present study aimed to evaluate the characteristics and quality of statistical methodology used in clinical studies on dentin hypersensitivity management. An electronic search was performed for data published from 2009 to 2014 by using PubMed, Ovid/MEDLINE, and Cochrane Library databases. The primary search terms were used in combination. Eligibility criteria included randomized clinical trials that evaluated the efficacy of desensitizing agents in terms of reducing dentin hypersensitivity. A total of 40 studies were considered eligible for assessment of quality statistical methodology. The four main concerns identified were i) use of nonparametric tests in the presence of large samples, coupled with lack of information about normality and equality of variances of the response; ii) lack of P-value adjustment for multiple comparisons; iii) failure to account for interactions between treatment and follow-up time; and iv) no information about the number of teeth examined per patient and the consequent lack of cluster-specific approach in data analysis. Owing to these concerns, statistical methodology was judged as inappropriate in 77.1% of the 35 studies that used parametric methods. Additional studies with appropriate statistical analysis are required to obtain appropriate assessment of the efficacy of desensitizing agents.

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Original
  • Maung Maung Kyaw Moe, Jung-Hong Ha, Myoung-Uk Jin, Young-Kyung Kim, S ...
    2017 Volume 59 Issue 4 Pages 469-474
    Published: 2017
    Released: December 27, 2017
    [Advance publication] Released: November 17, 2017
    JOURNALS FREE ACCESS

    This study evaluated the anatomical profile of the mesial root canals of the Burmese mandibular first molar with Vertucci’s type IV canal configuration (VT4) using microcomputed tomography analysis. Seventy-five mesial roots of extracted mandibular first molars were scanned and evaluated. Fourteen middle mesial canals (MMCs) were observed in the specimens; each specimen had an average of 1.63 lateral canals and 3.77 apical foramina. The lateral canals arising from the mesiobuccal canal, mesiolingual canal, MMC, and isthmus terminated at an average distance of 0.92, 0.73, 2.11, and 1.89 mm, respectively, from the apex. The mean distance between the centers of the mesiobuccal and mesiolingual canals at 1.5 mm coronal to the furcation was 2.60 mm. A higher incidence of isthmus was observed in the apical 2-6-mm region compared with the apical 0-2-mm region (P < 0.05). The incidence of lateral canals in the isthmus was similar to that of the mesiobuccal and mesiolingual canals (P > 0.05). This study shows that the mesial root of the Burmese mandibular first molar with VT4 has complex anatomical profiles comprising MMCs and isthmus and their lateral canals.

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  • Xiang Hu, Yi Zhao, Qi-Wen Man, Rui-Fang Li, Bing Liu, Yi-Fang Zhao
    2017 Volume 59 Issue 4 Pages 475-481
    Published: 2017
    Released: December 27, 2017
    JOURNALS FREE ACCESS

    Bone resorption in the jaws is one of the most severe complications of keratocystic odontogenic tumors (KCOTs), and can be treated by either enucleation or marsupialization. However, the effects of marsupialization on bone regeneration adjacent to KCOTs, and the mechanisms involved, are still unclear. In this study, samples of 27 KCOTs were collected (20 before marsupialization and 7 after marsupialization) to detect the expression of bone regeneration-related molecules adjacent to KCOTs by immunohistochemistry and real-time quantitative polymerase chain reaction (qPCR). The results showed that bone formation was significantly enhanced in the KCOT capsule wall adjacent to bone after marsupialization, as demonstrated by alkaline phosphatase activity assay and immunostaining for bone morphogenetic protein. Moreover, immunohistochemistry revealed that osteoprotegerin (OPG) was up-regulated in the KCOT capsule wall adjacent to bone after marsupialization, while receptor activator of nuclear factor-κB ligand (RANKL) was down-regulated. Real-time qPCR also demonstrated increased expression of OPG after marsupialization, accompanied by a decrease in the expression of osteoclastogenesis-related molecules such as cathepsin K, matrix metalloproteinase-9, NFATc1, RANK and RANKL. This study provides further evidence that marsupialization may promote bone regeneration adjacent to KCOTs partially through regulation of the OPG/RANK/RANKL signaling pathway.

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  • Moustafa A. Elsyad, Salem M. Eltowery, Ashraf A. Gebreel
    2017 Volume 59 Issue 4 Pages 483-490
    Published: 2017
    Released: December 27, 2017
    [Advance publication] Released: October 31, 2017
    JOURNALS FREE ACCESS

    This study aimed to evaluate the peri-implant strain around mesially inclined implants used to retain mandibular overdentures with Locator resilient attachments. Four mandibular edentulous acrylic resin models received two implants in the canine areas with 0°, 5°, 10°, and 20° mesial inclinations. Overdentures were connected to the implants using Locator attachments. Pink nylon inserts (light retention) were used for all implant inclinations, and red inserts were used for 20° inclination (20°red). Four strain gages were bonded on the mesial (M), distal (D), buccal (B), and lingual (L) surfaces of each implant. Peri-implant strains were measured during bilateral and unilateral loading. The 20° inclination showed the highest strain, followed by 10° and 5°, and both 0° and 20°red presented with the lowest strain. Site D was associated with the highest strain, followed by M, B, and L, which showed the lowest strain values. Unilateral loading and the loading side presented with significantly higher strain values than bilateral loading and the nonloading side, respectively. Hence, in this study, strains around the two-implant-retained overdentures with Locator attachments increased with increases in mesial implant angulation, except when red male inserts were used.

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  • Ayako Okada, Kaoru Sogabe, Hiroaki Takeuchi, Masaaki Okamoto, Yoshiaki ...
    2017 Volume 59 Issue 4 Pages 491-498
    Published: 2017
    Released: December 27, 2017
    [Advance publication] Released: November 17, 2017
    JOURNALS FREE ACCESS

    Quantitative analysis of periodontal bacteria is considered useful for clinical diagnosis, evaluation and assessment of the risk of periodontal disease. The purpose of this study was to compare the effectiveness of sampling of saliva, supragingival and subgingival plaque for evaluation of periodontal bacteria. From each of 12 subjects, i) subgingival plaque was collected from the deepest pocket using a sterile paper point, ii) stimulated whole saliva was collected after chewing gum, and iii) supragingival plaque was collected using a tooth brush. These samples were sent to the medical examination laboratory for quantitative analysis of the counts of three periodontal bacterial species: Porphyromonas gingivalis, Treponema denticola, and Tannerella forsythia. The proportions of these bacteria in subgingival plaque were higher than those in saliva or supragingival plaque, but lower in subgingival plaque than in saliva or supragingival plaque. In several cases, periodontal bacteria were below the levels of detection in subgingival plaque. We concluded that samples taken from subgingival plaque may be more useful for evaluating the proportion of periodontal bacteria in deep pockets than is the case for other samples. Therefore, for evaluation of periodontal bacteria, clinicians should consider the characteristics of the specimens obtained using different sampling methods.

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  • Masashi Kimura, Ken Takada, Kenichiro Ishibashi, Hiroyuki Ohto, Akio S ...
    2017 Volume 59 Issue 4 Pages 499-503
    Published: 2017
    Released: December 27, 2017
    [Advance publication] Released: November 22, 2017
    JOURNALS FREE ACCESS

    Reconstruction of oral defects using flaps following resection of oral cancer has become a standard approach for restoration of oral function. The purpose of this study was to investigate chronological changes in the volume of such flaps used for reconstruction and the factors affecting flap volume. We performed a retrospective analysis of 17 patients who had undergone oral cancer resection and reconstruction with flaps. Measurements were performed using data from computed tomography, and the flaps were selected semi-automatically using a computer-operated region-of-interest system. The data indicated that the change in total flap volume at 1 year after surgery was 30.6%, and that body weight loss was a risk factor for volume reduction. Our results suggested that flaps should be at least 30% larger than the defects they are intended to repair. However, as large flaps have the potential to cause upper airway obstruction, flap volume should be determined on an individual basis according to defect size and location.

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  • Sayumi Inoue, Misao Kawara, Takashi Iida, Masatoshi Iwasaki, Osamu Kom ...
    2017 Volume 59 Issue 4 Pages 505-510
    Published: 2017
    Released: December 27, 2017
    [Advance publication] Released: August 31, 2017
    JOURNALS FREE ACCESS

    The aim of this study was to examine the effects of tray design and impression material on impression pressure in a clinical simulation model of an edentulous mandible. Two types of polyvinylsiloxane elastomer, one type of polyether elastomer, and one type of alginate were used. The three tray types had no relief, 0.36 mm of relief, or 1.4 mm of relief, with or without escape holes. Impression pressure was measured at the median alveolar crest, the bilateral alveolar crests corresponding to molars, and the bilateral buccal shelves. Impression pressure significantly differed in relation to tray design and sensor position. In trays without escape holes, impression pressure was highest at the median alveolar crest and lowest at the buccal shelves, for all impression materials. However, impression material had no significant effects on impression pressure. Our results suggest that bite-pressure load on alveolar crests can be alleviated by making an impression with a tray that has relief and escape holes, while applying pressure to buccal shelves and almost no pressure to alveolar crests.

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  • Haruto Hiraba, Hiroyasu Koizumi, Hiroshi Nogawa, Akihisa Kodaira, Kent ...
    2017 Volume 59 Issue 4 Pages 511-517
    Published: 2017
    Released: December 27, 2017
    JOURNALS FREE ACCESS

    The purpose of the current study was to evaluate the bonding performance of two single-liquid primers, which contained 6-(4-vinylbenzyl-n-propyl) amino-1,3,5-triazine-2,4-dithione (VTD) or 6-methacryloyloxyhexyl 2-thiouracil 5-carboxylate (MTU-6), used for bonding between metals and an acrylic resin. A gold alloy and high-purity titanium were used as adherend materials, and a transparent acrylic resin initiated with tri-n-butylborane derivative was selected as the luting material. Both adherends were treated with one of the primers and bonded with the luting material, after which shear bond strength was determined. Fourier transform infrared spectroscopy was used to analyze debonded resin specimens. Shear bond strength to gold alloy was significantly greater than that to titanium for both the VTD and MTU-6 primers. A trace of thiol structure, probably derived from VTD and MTU-6, was detected on resin surfaces debonded from gold alloy. These results indicate that the two organic sulfur compounds, which are stable in an atmospheric environment, are tautomerized into a thiol structure, thus allowing adsorption onto noble metals. In addition, the adsorbed thiol compounds contribute to chemical bonding between the acrylic resin and noble metal alloy, as polymerizable adhesive functional monomers.

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  • Baleegh Alkadasi, Saleem Abdulrab, Soheir Gaafer, Butchibabu Kalakonda ...
    2017 Volume 59 Issue 4 Pages 519-526
    Published: 2017
    Released: December 27, 2017
    [Advance publication] Released: October 31, 2017
    JOURNALS FREE ACCESS

    N-acetylcysteine (NAC) is an anti-oxidant drug that has been used as a mucolytic agent and a paracetamol antidote for many years. This study was designed to determine the efficacy of the adjunctive use of NAC for periodontal treatment. Thirty subjects with moderate-to-severe chronic periodontitis were randomized to surgery with NAC (600 mg; S-NAC), surgery only (S-nonNAC), and healthy control groups. Gingival crevicular fluid (GCF) samples were obtained from all patients and sRANKL levels were determined by enzyme-linked immunosorbent assay at baseline, and 1, 3, and 7 months post-surgery. Plaque and gingival indices, probing depths, and clinical attachment levels were recorded at the same time. There was a significant reduction in probing depth at 3 months in the S-NAC group when compared to the S-nonNAC group (P < 0.05). However, no statistically significant differences in plaque and gingival indices, probing depths, clinical attachment levels, and sRANKL levels in GCF were noted between the surgical treatment groups at the end of 7 months. Hence, the use of adjunctive NAC resulted in a significant reduction in probing depths in the S-NAC group when compared to the S-nonNAC group at 3 months, but no statistically significant differences in GCF sRANKL levels were observed in the sites that underwent surgical treatment with or without NAC at different time intervals.

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  • Jie Nie, Fu-Cong Tian, Zu-Hua Wang, Adrian U. Yap, Xiao-Yan Wang
    2017 Volume 59 Issue 4 Pages 527-532
    Published: 2017
    Released: December 27, 2017
    [Advance publication] Released: November 17, 2017
    JOURNALS FREE ACCESS

    This in vivo study aimed to evaluate the efficacy of in-office and home teeth bleaching in Asian patients. Moreover, the correlation between tooth color change and patient’s outcome satisfaction was investigated. Overall, 40 Chinese patients were randomly divided into two groups and prescribed in-office (OB) or take-home bleaching (HB). The color of the maxillary central incisor and canine were recorded at baseline, immediately after first treatment, 1 week, and 3 months after treatment by using a spectrophotometer. Bleaching sensitivity and outcome satisfaction were assessed using Likert and visual analogue scale (VAS), and the results were analyzed using independent t-test and Pearson correlation (P < 0.05). ΔL*, Δa*, Δb*, and ΔE* values of HB were greater than those of OB. Color changes observed in canines were generally greater than those in incisors. Moreover, HB was generally associated with less tooth sensitivity than OB. Patients were satisfied with both treatments, but VAS scores were greater for HB. Furthermore, the correlation between ΔE* and VAS was significant for canines immediately after the first treatment and 1 week after HB. In conclusion, HB was more effective in lightening teeth and reducing chromacity in Chinese patients. The correlation between tooth color change and outcome satisfaction was generally insignificant and weak.

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  • Kazunori Nakajima, Tetsurou Odatsu, Ayano Shinohara, Koumei Baba, Yasu ...
    2017 Volume 59 Issue 4 Pages 533-539
    Published: 2017
    Released: December 27, 2017
    JOURNALS FREE ACCESS

    The aim of this study was to develop an effective method for cleaning implant abutments made by computer-aided design and computer-aided manufacturing techniques and to investigate the effect of decontamination in vitro. Briefly, a newly developed reagent (PK) and/or vacuum plasma (Plasma) were used to clean the surfaces of zirconia disks, and the effects of this decontamination were evaluated by X-ray photoelectron spectroscopy. Human gingival fibroblasts (HGFs) were cultured on sample disks for 6, 24, and 48 h. We evaluated cell attachment and gene expression of the acute inflammatory cytokines interleukin-6 and vascular endothelial growth factor A, and type 1 collagen. In the PK and PK+Plasma groups, surface contaminants were reduced by washing. In addition, HGF attachments was increased in the PK and PK+Plasma groups. Gene expressions of interleukin-6 and vascular endothelial growth factor A were lower at 6 h. Gene expression of type 1 collagen was increased at all time points after seeding. These results suggest that decontamination of implant abutment surfaces is important in initial HGF attachment and may improve the biological seal of peri-implant soft tissue.

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  • Hiroyasu Noguchi, Takashi Iwase, Daisuke Omagari, Masatake Asano, Ryot ...
    2017 Volume 59 Issue 4 Pages 541-547
    Published: 2017
    Released: December 27, 2017
    JOURNALS FREE ACCESS

    Loop-mediated isothermal amplification (LAMP) rapidly amplifies DNA under isothermal conditions. The aim of this study was to detect Candida albicans and compare the positivity rate in the LAMP reaction with that of conventional methods for oral exfoliative cytology (EC) samples. Sixty-eight EC samples from 53 patients were subjected to LAMP analysis. These patients had been clinically diagnosed with leukoplakia, squamous cell carcinoma, oral lichen planus (OLP), stomatitis, oral candidiasis, and other malignancies. LAMP reactions were defined as positive when the sample turbidity exceeded 0.1 (arbitrary unit). Periodic acid-Schiff (PAS) staining and microbial culture were also performed to detect Candida species in EC samples. The LAMP reaction detected C. albicans in 42.6% of EC samples. Candida species were detected in 32.4% of the same samples by culturing and in 29.4% of samples by PAS staining. C. albicans DNA was detected most frequently in samples from OLP patients. We conclude that, in comparison to conventional methods for detection of C. albicans, the LAMP method is highly sensitive and time-saving, and does not require expensive equipment or diagnostic technology. It may therefore be useful for on-site screening of C. albicans at dental clinics.

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  • Taiji Ogawa, Mariko Honda-Ogawa, Kazunori Ikebe, Yumiko Notomi, Yoshik ...
    2017 Volume 59 Issue 4 Pages 549-555
    Published: 2017
    Released: December 27, 2017
    [Advance publication] Released: October 06, 2017
    JOURNALS FREE ACCESS

    Over 700 bacterial species have been detected in the oral cavity. Several studies have suggested that periodontitis is associated with systemic disorders such as diabetes mellitus, indicating a key role for oral microbiota in human health. However, the relationship between oral microbiota and diabetes has not been well clarified. Therefore, we conducted microbiome analysis of saliva samples obtained from 15 elderly residents (3 with type 2 diabetes mellitus [DM] and 12 without diabetes [non-DM]) at three different nursing homes, as well as 9 young healthy controls (HC). Genomic DNA was extracted from each sample, and then the V4 region of the 16S rRNA gene was amplified and sequenced. Alpha diversity, in terms of operational taxonomic unit richness, was significantly higher in samples from the non-DM group than in those from the HC group. Weighted UniFrac distance analysis showed that salivary microbial communities in the DM group were separately clustered. Furthermore, in the DM group, Actinomyces and Selenomonas showed significantly higher abundance, whereas Alloprevotella showed significantly lower abundance, relative to the non-DM group. Although our findings were limited by the small sample size, oral bacterial diversity in the DM group was clearly different from that in the non-DM group.

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  • Manabu Ishikawa, Yuri Aono, Tadashi Saigusa
    2017 Volume 59 Issue 4 Pages 557-564
    Published: 2017
    Released: December 27, 2017
    [Advance publication] Released: October 06, 2017
    JOURNALS FREE ACCESS

    We analysed the roles of orexin receptors in the effects of orexin-A on KCl-induced increases in intracellular calcium ion levels ([Ca2+]i) in C-fiber-like small neurons of rats with inflammation induced by intraplantar injection of carrageenan into the hind paw. Controls were treated with saline. Paw withdrawal and threshold forces in response to tactile stimuli were determined using von Frey filaments. [Ca2+]i in C-fiber-like neurons derived from dorsal root ganglia was visualised using a calcium fluorescence probe. Changes in neuronal [Ca2+]i were assessed as relative fluorescence intensity (F/F0). One day after carrageenan injection, the paw withdrawal response to tactile stimuli and the paw withdrawal threshold were increased and reduced, respectively. KCl loading of neurons from either carrageenan-treated or control rats increased F/F0 to about 2.0. KCl-induced increases in F/F0 of carrageenan-treated, but not control, rats were inhibited by orexin-A. The OX1 and OX2 receptor antagonist MK-4305, but not the OX1 receptor antagonist SB334867, counteracted the effects of orexin-A on the KCl-induced increase in F/F0. These results suggest that OX2, but not OX1 receptors mediate the inhibitory effect of orexin-A on KCl-induced increases in [Ca2+]i in C-fiber-like neurons of rats with inflammation.

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  • Zaid A. Al Jeaidi, Mohammed A. Alqahtani, Mohamed M. Awad, Flávia P. R ...
    2017 Volume 59 Issue 4 Pages 565-570
    Published: 2017
    Released: December 27, 2017
    JOURNALS FREE ACCESS

    The bond strength of universal adhesives to air-abraded zirconia ceramic was evaluated. Overall, 40 zirconia ceramic blocks with dimensions of 6 × 6 × 4 mm were cut from pre-sintered blanks. The sintered blocks were embedded in self-cured acrylic resin. The zirconia blocks were then randomly allocated to four groups (n = 10) in which different universal adhesives were used, except for the control group in which no universal adhesive was used. A silicon mold was used to build the resin cement. All specimens were stored in distilled water for 24 h at 37°C and mounted on a universal testing machine. They were then subjected to shear bond strength testing at a cross-speed of 0.5 mm/min until failure occurred. The failure modes were analyzed using a digital microscope at 50× magnification. Univariate one-way analysis of variance and Tukey’s post-hoc test were used for statistical analysis. Compared with the control group, the groups with universal adhesives showed statistically significant differences (P < 0.05). In addition, there was no statistically significant difference in the bond strengths of the groups with universal adhesives (P > 0.05) . After 24 h of storage, the cementation bond to air-abraded zirconia ceramic was improved by the application of a universal adhesive.

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  • Hidekazu Nagashima, Masamichi Shinoda, Kuniya Honda, Noriaki Kamio, Ak ...
    2017 Volume 59 Issue 4 Pages 571-577
    Published: 2017
    Released: December 27, 2017
    [Advance publication] Released: October 31, 2017
    JOURNALS FREE ACCESS

    Periodontitis caused by bacterial infection gradually progresses accompanied by periodontal tissue destruction. As a result, teeth lose their supporting structures, and this leads to tooth exfoliation. CXC-chemokine receptor 4 (CXCR4) is known to be expressed in lymphocytes, fibroblasts and osteoclasts in periodontal tissues, suggesting that periodontal CXCR4 signaling contributes to alveolar bone resorption in the milieu of periodontitis. However, the role of CXCR4 signaling in the pathogenesis of periodontitis has remained unknown. We established a mouse model of periodontitis by inoculation of Porphyromonas gingivalis (P.g.) into a silk ligature placed around the maxillary molar. Although there was no significant difference in the mechanical sensitivity in the periodontal tissue between P.g. treatment and sham treatment during the experimental period, mechanical allodynia in the periodontal tissue was induced after gingival injection of complete Freund’s adjuvant compared with that resulting from sham and P.g. treatment alone. Moreover, CXCR4 neutralization in the periodontal tissue following P.g. treatment enhanced periodontal inflammatory cell infiltration and depressed alveolar bone resorption. These findings suggest that periodontal CXCR4 signaling in several cell types in P.g.-induced periodontal inflammation depresses alveolar bone resorption in periodontitis. CXCR4 signaling might be a target for therapeutic intervention to prevent alveolar bone resorption in periodontitis.

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  • Amira M. Elsherbini, Mohammed A. R. Mohammed, Fatma M. Ibrahim
    2017 Volume 59 Issue 4 Pages 579-588
    Published: 2017
    Released: December 27, 2017
    [Advance publication] Released: October 06, 2017
    JOURNALS FREE ACCESS

    The epigenetic nature of development mandates the observation of the effect of any exogenous substance, especially those with estrogenic activities, during critical phases of development. The submandibular gland (SMG) presents as a great model due to extensive postnatal development, and is known to be regulated and affected by hormones as well as growth factors. Herein, we observed postnatal development following low doses of Biochanin A (BCA) and 17β estradiol (E2) in rats. The pups were randomly divided into four groups: control, BCA, E2, and dimethyl sulfoxide (DMSO), and euthanized at the 6th, 15th, 30th, and 60th postnatal days (PND). SMG morphogenesis was assessed. The nuclear expression of estrogen receptor beta (ERβ) was evaluated immunohistochemically; ERβ expression was up-regulated by BCA and down-regulated by E2. Similarly, caspase three gene expression, assessed by real time polymerase chain reaction was increased in the BCA group but decreased in the E2 group. A significant decrease in epidermal growth factor gene expression was noted at PND 30. The results presented by this study provide evidence that the effect of a postnatal exposure of the SMG to Biochanin A during development could be linked to sex hormone-dependent disorders.

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  • Kazuyuki Handa, Natsuko Murakami, Toshiki Yamazaki, Hidekazu Takahashi ...
    2017 Volume 59 Issue 4 Pages 589-596
    Published: 2017
    Released: December 27, 2017
    [Advance publication] Released: November 17, 2017
    JOURNALS FREE ACCESS

    The purpose of this study was to investigate the wear volume and the principal strain of machinable dental composite and ceramics in simulated mastication. A ball-on-disk wear test was performed for 3,000 cycles in water, using nine ball/disk combinations of three commercial CAD/CAM materials: feldspathic, lithium disilicate glass ceramics, and a highly loaded composite material (n = 7 for each combination). The wear volume was optically measured using a digital scanner and analyzed for statistical differences based on the materials (α = 0.05). We used non-linear finite element analysis to calculate the principal strain. The wear volume of the ball was significantly larger than that of the disk when hardness and fracture toughness of the former was lower than that of the latter and vice versa (P < 0.05). The lithium disilicate glass ceramic constantly showed lower wear volume than the opposing antagonist. Except for the same material pairs of feldspathic and composite, the ball or disk specimen that showed a larger wear in the occluding pair coincided with the one with higher maximum strain. It was not possible to predict the magnitude of wear, whereas the result suggested a strong association between the maximum strain and wear volume of the ceramic surface.

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  • Takahiro Mitsui, Ryô Harasawa
    2017 Volume 59 Issue 4 Pages 597-601
    Published: 2017
    Released: December 27, 2017
    [Advance publication] Released: October 31, 2017
    JOURNALS FREE ACCESS

    Dietary nitrate is reduced to nitrite and nitric oxide by microbial flora, and this activity is beneficial to vascular health. It has been reported that this bacterial process is inhibited by chlorhexidine mouthwash, although the effects of other products are largely unknown. This study examined the effects of several treatments on salivary nitrate/nitrite and nitrate-reducing bacteria. Twelve university staff and students performed mouth-washing with water (control), essential oil, 0.35% povidone-iodine, or 0.0025% chlorhexidine and then ate 100 g lettuce (110 mg nitrate content), followed by collection of saliva and tongue bacteria at the baseline, and 1, 5, and 10 h thereafter. The individual treatments were separated by an interval of one week. Salivary nitrate/nitrite was measured by the calorimetric method, and a representative nitrate-reducing bacterial species, Veillonella dispar, was detected and semi-quantified using a polymerase chain reaction (PCR) assay. Significant increases in salivary nitrate/nitrite were observed for all treatments (all P < 0.05). The PCR assay showed that water, essential oil, and povidone-iodine mouthwash had little effect, whereas V. dispar DNA bands were markedly inhibited after washing with chlorhexidine. These results suggest that essential oil and povidone-iodine mouthwash have little effect on oral nitrate-reducing activity. Salivary nitrite production was not reduced by chlorhexidine, but the fainter band of V. dispar DNA suggests that longer daily use might blunt this nitrate-reducing activity.

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  • Yuko Yamamoto, Nobuhisa Kubota, Toru Takahashi, Masahiro To, Takashi H ...
    2017 Volume 59 Issue 4 Pages 603-610
    Published: 2017
    Released: December 27, 2017
    JOURNALS FREE ACCESS

    Immunoglobulin A (IgA), which plays an important role in infection defense, is upregulated in the large intestine and oral cavity through dietary fiber intake. However, the mechanism underlying salivary IgA increase through dietary fiber intake remains unknown. This study investigated time-dependent effects of non-absorbable polydextrose (PDX) and lactitol intake on salivary IgA secretion and cecal fermentation. Five-week-old rats were fed a fiber-free diet with or without 25 g/kg PDX and 25 g/kg lactitol for 1, 4, and 8 weeks. Compared to control, those who ingested PDX and lactitol had higher salivary IgA flow rates per weight of submandibular gland tissue at 4 and 8 weeks (P < 0.05), greater cecal weight and digesta at 1, 4, and 8 weeks (P < 0.05), and lower concentrations of short chain fatty acids (SCFAs) in cecal digesta (P = 0.0003). These findings suggest that the consumption of PDX and lactitol may upregulate salivary IgA secretion possibly by stimulating absorption of SCFAs produced by cecal fermentation. Thus, continuous ingestion of PDX and lactitol for up to 4 weeks could increase salivary IgA and promote immune defense against pathogen invasion through the oral route.

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  • Daigo Suzuki, Daisuke Akita, Niina Tsurumachi, Koichiro Kano, Katsuyuk ...
    2017 Volume 59 Issue 4 Pages 611-620
    Published: 2017
    Released: December 27, 2017
    JOURNALS FREE ACCESS

    The transplantation of dedifferentiated fat (DFAT) cells in combination with poly(d,l-lactic-co-glycolic acid) (PLGA) scaffolds has previously been proven as an effective approach in promoting periodontal tissue regeneration in a rat fenestration defect model. The aim of this study was to assess the regenerative potential of DFAT cells in a rat model of three-wall periodontal bone defect. Three-wall bone defects were created bilaterally on the mesial side of rat maxillary first molars and were either left untreated or treated by implantation of PLGA scaffolds with DFAT cells or PLGA alone. Four weeks after surgery, the tissues were processed for micro-computed tomography (micro-CT) and histomorphometric examination. Micro-CT revealed that the PLGA/DFAT group had significantly higher rates of bone regeneration than the other groups, while histomorphometric analysis showed that the PLGA/DFAT group had significantly higher densities of collagen fiber bundles in acellular and cellular cementum than the PLGA group. Moreover, the results indicate that the placement of the PLGA scaffold prevented the downgrowth of the junctional epithelium. These findings suggest that DFAT cells contribute to tissue regeneration in three-wall periodontal defects, while PLGA provides space necessary for periodontal tissue restoration.

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  • Shiwei Cai, Wenjian Zhang, Gena Tribble, Wei Chen
    2017 Volume 59 Issue 4 Pages 621-627
    Published: 2017
    Released: December 27, 2017
    JOURNALS FREE ACCESS

    An ideal pulp-capping agent needs to have good biocompatibility and promote reparative dentinogenesis. Although the effects of capping agents on healthy pulp are known, limited data regarding their effects on bacterial contaminated pulp are available. This study aimed to evaluate the reaction of contaminated pulps to various capping agents to assist clinicians in making informed decisions. Human dental pulp (HDP) cell cultures were developed from extracted human molars. The cells were exposed to a bacterial cocktail comprising Porphyromonas gingivalis, Prevotella intermedia, and Streptococcus gordonii before being cocultured with capping agents such as mineral trioxide aggregate (MTA) Portland cement (PC), and Dycal. HDP cell proliferation was assayed by MTS colorimetric cell proliferation assay, and its differentiation was evaluated by real-time PCR for detecting alkaline phosphatase, dentin sialophosphoprotein, and osteocalcin expressions. MTA and PC had no apparent effect, whereas Dycal inhibited HDP cell proliferation. PC stimulated HDP cell differentiation, particularly when they were exposed to bacteria. MTA and Dycal inhibited differentiation, regardless of bacterial infection. In conclusion, PC was the most favorable agent, followed by MTA, and Dycal was the least favorable agent for supporting the functions of bacterial compromised pulp cells.

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  • Shinya Iguchi, Daigo Suzuki, Eisuke Kawano, Takayuki Mashimo, Mikihito ...
    2017 Volume 59 Issue 4 Pages 629-637
    Published: 2017
    Released: December 27, 2017
    JOURNALS FREE ACCESS

    Bone marrow-derived multipotent stromal cells (BMSCs) have potent antiinflammatory effects. This study aimed to investigate the antiinflammatory potential of BMSCs using a mouse model of ligature-induced periodontitis. BMSCs were isolated from the femurs and tibiae of mice. Periodontitis was induced by placing a ligature around the right maxillary second molar. After 3 days, the mice were administered BMSC in the gingiva of the mesial interdental papilla around the ligatured molar. The ligatured and non-ligatured mice that were not administered BMSC served as controls. Differences in inflammatory infiltration and bone resorption around the roots of the second molar were assessed and were subsequently quantified using microcomputed tomography (micro-CT), histological analysis, and tartrate-resistant acid phosphatase (TRAP) staining. Micro-CT revealed that alveolar bone loss around the ligatured molars increased in a time-dependent manner; however, the effect was significantly less in BMSC-treated mice compared with ligatured control mice. Tissue histopathology revealed that BMSC administration mitigated inflammatory infiltration in ligatured BMSC mice. In addition, the number of TRAP-positive osteoclasts was markedly elevated in ligatured control mice compared with those in BMSC-treated mice. These findings indicate that local BMSC administration can mitigate inflammation and alveolar bone resorption, suggesting that administering BMSC leads to new therapeutics for periodontitis.

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  • Leonardo S. Antunes, Lais Veiga, Victor S. Nery, Caio C. Nery, Lívia A ...
    2017 Volume 59 Issue 4 Pages 639-643
    Published: 2017
    Released: December 27, 2017
    JOURNALS FREE ACCESS

    This cross-sectional study assessed the prevalence and potential risk factors for dental erosion in amateur athletes at running events. After a sample calculation, 108 runners from the state of Rio de Janeiro, Brazil, were selected and examined for dental wear by a single trained and calibrated evaluator (kappa = 1.00). To identify risk factors, the runners were interviewed by using a standardized, semi-structured questionnaire. The average (SD) age of the runners was 34.2 (11.45), and the prevalence of dental erosion was 19.4%. Gastroesophageal reflux, running frequency per week, and time expended during competition were associated with dental erosion (P < 0.05). The association between use of isotonic drinks and dental erosion was not significant (P > 0.05). In conclusion, dental erosion was not associated with use of isotonic drinks. However, frequency of exercise per week and gastroesophageal reflux were risk factors for dental erosion.

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