Journal of Oral Science
Online ISSN : 1880-4926
Print ISSN : 1343-4934
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Review
  • Yoshimasa Takeuchi, Hiroyasu Koizumi, Mika Furuchi, Yohei Sato, Chikah ...
    Volume 60 (2018) Issue 1 Pages 1-7
    Released: March 24, 2018
    JOURNALS FREE ACCESS

    Accurate impressions are essential in fabri-cating dental restorations and fixed dental prostheses. During the last decade, digital impression systems have improved substantially. This review discusses the accuracy of digital impression systems for fabrication of dental restorations and fixed dental prostheses. A literature search in PubMed was performed for the period from July 2010 through June 2017. The search keywords were Cerec, digital impression, direct digitalization, indirect digitalization, and intraoral scanner. Only relevant studies are summarized and discussed in this review. In general, the latest systems have considerably reduced the time required for impression making, and the accuracy and marginal fit of digital impression systems have recently improved. Restorations and fixed dental prostheses fabricated with currently available digital impression systems and intraoral scanners exhibit clinically acceptable ranges of marginal gap in both direct and indirect procedures.

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Original
  • Tetsuro Watase, Kohei Shimizu, Hiroki Komiya, Kinuyo Ohara, Koichi Iwa ...
    Volume 60 (2018) Issue 1 Pages 8-13
    Released: March 24, 2018
    [Advance publication] Released: February 26, 2018
    JOURNALS FREE ACCESS

    A study was conducted to evaluate the mechanisms underlying ectopic orofacial pain associated with tooth pulp inflammation in rats. We observed a significant decrease in the head withdrawal threshold (HWT) response to mechanical and heat stimuli applied to the ipsilateral facial skin upon application of complete Freund’s adjuvant (CFA) to the upper first molar (M1TP) in comparison to application of vehicle. A large number of trigeminal ganglion (TG) neurons showed transient receptor potential vanilloid 1 (TRPV1) immunoreactivity (IR), and some of them were retrogradely labeled with fluorogold injected into the facial skin. A large number of cells showing IR for glial fibrillary acidic protein (GFAP) were observed in the 2nd compared to the 1st or 3rd branch regions of the TG, and TG cells innervating the facial skin were also surrounded by GFAP-IR cells. After administration of TRPV1 antagonist into the facial skin of M1TP CFA-treated rats, the decrease of HWTs in response to mechanical and heat stimulation of the facial skin was significantly reversed. The present findings suggest that the excitability of TG neurons is enhanced upon tooth pulp inflammation, leading to overexpression of TRPV1 in TG neurons innervating the facial skin, and that satellite glial cells are also activated, resulting in the development of ectopic orofacial pain.

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  • Niina Tsurumachi, Daisuke Akita, Koichiro Kano, Taro Matsumoto, Taku T ...
    Volume 60 (2018) Issue 1 Pages 14-23
    Released: March 24, 2018
    [Advance publication] Released: February 26, 2018
    JOURNALS FREE ACCESS

    Dedifferentiated fat (DFAT) cells were isolated from mature adipocytes using the ceiling culture method. Recently, we successfully isolated DFAT cells from adipocytes with a relatively small size (<40 μm). DFAT cells have a higher osteogenic potential than that of medium adipocytes. Therefore, the objective of this study was to determine the optimal concentration of collagenase solution for isolating small adipocytes from human buccal fat pads (BFPs). Four concentrations of collagenase solution (0.01%, 0.02%, 0.1%, and 0.5%) were used, and their effectiveness was assessed by the number of small adipocytes and DFAT cells isolated. The total number of floating adipocytes that dissociated with 0.02% collagenase was 2.5 times of that dissociated with 0.1% collagenase. The number of floating adipocytes with a diameter of ≤29 μm that dissociated with 0.02% collagenase was thrice of those dissociated with 0.1% and 0.5% collagenase. The number of DFAT cells that dissociated with 0.02% collagenase was 1.5 times of that dissociated with 0.1% collagenase. In addition, DFAT cells that dissociated with 0.02% collagenase had a higher osteogenic differentiation potential than those that dissociated with 0.1% collagenase. These results suggest that 0.02% is the optimal collagenase concentration for isolating small adipocytes from BFPs.

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  • Tamer Tüzüner, Zeynep A. Güçlü, Andrew Hurt, Nichola J. Coleman, John ...
    Volume 60 (2018) Issue 1 Pages 24-28
    Released: March 24, 2018
    JOURNALS FREE ACCESS

    This study examined the release of cetylpyridinium chloride and benzalkonium chloride from fatty acid chelate temporary dental cement and their antimicrobial effects. The cement was Cavex Temporary, and either cetylpyridinium chloride or benzalkonium chloride was added (1% or 5% by mass), incorporating into the base paste. Release of the additives was determined by reverse-phase high-performance liquid chromatography. Possible chemical interactions between the cement components and additives were examined by Fourier transform infrared (FTIR) spectroscopy. Antimicrobial effects were assessed by measuring the zone of inhibition around sample discs after 24 h in a Streptococcus mutans culture. FTIR spectroscopy showed no interaction with cement components. For both additives, release was by diffusion for approximately the first 6 hours, with equilibration after about 2 weeks. Diffusion coefficients were 1.76 m2 s½ to 8.05 × 10−12 m2 s½ and total release was 10.3 to 44.7% of additive loading. Zones of inhibition with additive were significantly larger than those for control discs. In conclusion, the antimicrobial properties of Cavex temporary cement are improved by the addition of the antimicrobial compounds cetylpyridium chloride and benzalkonium chloride, which are released by a diffusion process.

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  • Akimasa Tsujimoto, Wayne W. Barkmeier, Toshiki Takamizawa, Hidehiko Wa ...
    Volume 60 (2018) Issue 1 Pages 29-36
    Released: March 24, 2018
    [Advance publication] Released: January 29, 2018
    JOURNALS FREE ACCESS

    This study evaluated the simulated localized wear of resin luting cements for universal adhesive systems using different curing modes. Five resin luting cements for universal adhesive systems were evaluated and subsequently subjected to wear challenge in a Leinfelder-Suzuki wear simulation device. Overall, 20 specimens from each resin luting cement were photo-cured for 40 s (dual-cure group), and 20 specimens of each material were not photo-cured (chemical-cure group). Simulated localized wear was generated using a stainless steel ball-bearing antagonist in water slurry of polymethylmethacrylate beads. In addition, scanning electron microscopy (SEM) observations of resin luting cements and wear facets were conducted. Significant differences in simulated wear and SEM observations of wear facets were evident among the materials in the dual- and chemical-cure groups. The simulated wear and SEM observations of wear facets of G-CEM LinkForce and Panavia V5 were not influenced by the curing mode. SEM observations of resin luting cements were material dependent. In most cases, dual curing appears to ensure greater wear resistance of resin luting cements than chemical curing alone. The wear resistance of some resin luting cements appears to be material dependent and is not influenced by the curing mode.

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  • Rantaro Kamimura, Mohammad Z. Hossain, Shumpei Unno, Hiroshi Ando, Yuj ...
    Volume 60 (2018) Issue 1 Pages 37-44
    Released: March 24, 2018
    [Advance publication] Released: March 02, 2018
    JOURNALS FREE ACCESS

    Current therapeutics are not effective for orofacial neuropathic pain, and better options are needed. The present study used inferior orbital nerve (ION)-injured mice to investigate the effect of inhibiting monoacylglycerol lipase (MAGL), an enzyme that degrades the major endocannabinoid 2-arachydonoylgycerol (2-AG) in orofacial neuropathic pain. The head-withdrawal threshold to mechanical stimulation of the whisker pad was reduced on days 3, 5, and 7 after ION injury. Injection of JZL184, a selective inhibitor of MAGL, on day 7 after ION injury attenuated the reduction in head-withdrawal threshold at 2 h after administration. Moreover, the numbers of MAGL-immunoreactive neurons in the trigeminal subnucleus caudalis (Vc) and upper cervical spinal cord (C1-C2) were significantly greater in ION-injured mice than in sham-operated mice but were reduced after administration of JZL184. The increase in MAGL immunoreactivity suggests that increased 2-AG production is followed by rapid enzymatic degradation of 2-AG. JZL184 inhibited this degradation and thus increased 2-AG concentration in the brain, particularly in the Vc and C1-C2 regions, thus attenuating pain. Our findings suggest that inhibition of 2-AG degradation by MAGL inhibitors is a promising therapeutic option for treatment of orofacial neuropathic pain.

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  • Omar Kujan, Michael N. Pemberton, Martin Schwarz, Philip Sloan
    Volume 60 (2018) Issue 1 Pages 45-50
    Released: March 24, 2018
    [Advance publication] Released: January 29, 2018
    JOURNALS FREE ACCESS

    The present study was conducted to assess the applicability of liquid-based cytology (LBC) using an innovative oral brush, Orcellex. Fifty healthy volunteers were recruited. From each subject, four samples were collected using “Orcellex” from apparently normal oral mucosal sites. A plastic spatula was also used to obtain an additional sample. Data on the tolerability and acceptability of the Orcellex were collected from the subjects, together with assessments of the adequacy of LBC slide preparations for cellularity, preparation quality, and the types of cells observed. The Orcellex brush was well accepted by the volunteers, who reported relatively little pain. Orcellex brush LBC preparations were of good quality in terms of cell morphology and staining, with a clean background. Only two smears (2/200; 1%) were found to be inadequate due to low cellularity. All of the plastic spatula LBC preparations were inadequate. Representative cells from all layers of the different oral epithelia examined were documented. Oral liquid-based cytology using the Orcellex brush may have considerable potential for early detection of oral cancer and precancer.

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  • Mia-Michaela Beetge, Vladimir S. Todorovic, Anna Oettlé, Jakobus Hoffm ...
    Volume 60 (2018) Issue 1 Pages 51-56
    Released: March 24, 2018
    [Advance publication] Released: February 26, 2018
    JOURNALS FREE ACCESS

    The greater palatine foramen (GPF) is an important anatomical landmark and has substantial clinical relevance in dental surgery. Knowledge of its precise location and dimensions is required for proper planning of surgical procedures involving the posterior maxilla. We used microfocus computed tomography to determine the location and dimensions of the GPF, and any sex and race variations in those measurements, in 77 human skulls scanned at the South African Nuclear Energy Corporation. Specialized software was used for three-dimensional rendering, segmentation, and visualization of the reconstructed volume data. GPF location ranged from adjacent to the first molar to distal of the third molar. The most common GPF location was near the third molar (66.7% of skulls), and the GPF was as close as 6.31 mm (mean distance 12.75 ± 3 mm). The mean GPF dimensions were 5.22 mm on the anterior-posterior axis and 2.81 mm on the lateral-medial axis. We noted no significant differences in relation to race, sex, or age in the sample. The GPF was adjacent or posterior to the third maxillary molar in most skulls.

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  • Omid Dianat, Fatemeh Mashhadiabbas, Zohreh Ahangari, Sara Saedi, Saeed ...
    Volume 60 (2018) Issue 1 Pages 57-63
    Released: March 24, 2018
    [Advance publication] Released: February 26, 2018
    JOURNALS FREE ACCESS

    Previous in vitro studies have suggested that simvastatin can be used as a direct pulp capping material due to its ability to induce odontoblastic differentiation and angiogenesis. The aim of this animal study was to evaluate the pulpal response to mineral trioxide aggregate (MTA) and four concentrations of simvastatin/MTA in combination. The study was conducted in two stages using four different simvastatin concentrations and MTA as a capping material for rat maxillary molars. The grades of inflammation and continuity of dentin formation were evaluated in hematoxylin and eosin (HE)-stained samples. Dentin thickness was determined by histomorphometric analysis, and the data were subjected to statistical analysis. On day 3, mild inflammation was observed in all groups. On day 7, the simvastatin groups showed a slightly higher rate of chronic inflammation. Inflammation was not present on day 30. Discontinuous dentin was present in all methylcellulose (control) samples. Continuous dentin was formed in all of the samples treated with 1.5% simvastatin. The greatest dentin thickness was observed after treatment with 1.5% simvastatin and MTA, followed by 0.5% simvastatin. Statistical analysis demonstrated no significant differences in dentin thickness and continuity between MTA and simvastatin at 0.5% and 1.5% (P > 0.05).

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  • Yu-Chuan Tseng, Chin-Yun Pan, Pao-Hsin Liu, Yi-Hsin Yang, Hong-Po Chan ...
    Volume 60 (2018) Issue 1 Pages 64-69
    Released: March 24, 2018
    JOURNALS FREE ACCESS

    This study used resonance frequency (RF) analysis to assess miniscrew implant (MSI) stability during wound healing in a sample of 68 patients (41 women, 27 men; mean age, 27.7 years). The 104 MSIs included 66 placements in the buccal shelf (BS; 2.0 × 12 mm) and 38 placements in interradicular (IR; 1.5 × 8 mm) sites. Thirteen (12.5%) of the MSIs failed. A new RF detection device was used to measure RF at baseline (T0) and at 3 (T1), 6 (T2), 9 (T3), 12 (T4), and 15 (T5) weeks after placement. A linear mixed-effects model was fitted to change in RF values. As compared with the BS group, the IR group had significantly lower RF values on the right side from T0 through T4 and on the left side from T0 through T2. Insertion site and time of visit were significantly associated with RF value. The effects of time of visit significantly differed between the BS and IR sites. Starting from T0, the MSIs placed at both sites had significantly lower RF values at all intervals, except for T0-T1. Future studies should examine how the present clinical protocols can optimize timing of MSI loading to maximize the success rate.

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  • Ilda P. Ribeiro, Joana M. Rodrigues, Alexandra Mascarenhas, Nadezda Ko ...
    Volume 60 (2018) Issue 1 Pages 70-81
    Released: March 24, 2018
    [Advance publication] Released: February 26, 2018
    JOURNALS FREE ACCESS

    Oral carcinoma develops from squamous epithelial cells by the acquisition of multiple (epi) genetic alterations that target different genes and molecular pathways. Herein, we performed a comprehensive genomic and epigenetic characterization of the HSC-3 cell line through karyotyping, multicolor fluorescence in situ hybridization, array comparative genomic hybridization, and methylation-specific multiplex ligation-dependent probe amplification. HSC-3 turned out to be a near-triploid cell line with a modal number of 61 chromosomes. Banding and molecular cytogenetic analyses revealed that nonrandom gains of chromosomal segments occurred more frequently than losses. Overall, gains of chromosome 1, 3q, 5p, 7p, 8q, 9q, 10, 11p, 11q13, 12, 13, 14, 17, 18p, 20, Yp, and Xq were observed. The largest region affected by copy number loss was observed at chromosome 18q. Several of the observed genomic imbalances and their mapped genes were already associated with oral carcinoma and/or adverse prognosis, invasion, and metastasis in cancer. The most common rearrangements observed were translocations in the centromeric/near-centromeric regions. RARB, ESR1, and CADM1 genes were methylated and showed copy number losses, whereas TP73 and GATA5 presented with methylation and copy number gains. Thus, the current study presents a comprehensive characterization of the HSC-3 cell line; the use of this cell line may contribute to enriching the resources available for oral cancer research, especially for the testing of therapeutic agents.

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  • Bahram Ranjkesh, Flemming Isidor, David Christian Evar Kraft, Henrik L ...
    Volume 60 (2018) Issue 1 Pages 82-88
    Released: March 24, 2018
    JOURNALS FREE ACCESS

    A novel fast-setting calcium silicate cement with fluoride (CSC) has been developed for potential application in tooth crowns. This study compared the cytotoxicity of CSC compositions and a variety of dental materials. We tested CSC compositions (Protooth), MTA, Biodentine, Ketac Molar, Fuji II LC, Vitrebond, DeTrey Zinc, Dycal, and IRM, DMEM (negative control) and 1% NaOCl (positive control). After setting of cements for 24 h, specimens were immersed in DMEM for 24 h to obtain material elutes. The elutes were serially diluted in serum-free DMEM to obtain three dilutions. L929 mouse fibroblast cells (1 × 104 cells per well) were treated for 24 h with elute dilutions (n = 3). Cytotoxicity was determined using methyl-thiazolyl-tetrazolium assay in triplicate. CSC compositions, MTA, and Biodentine showed no significant reduction in cell viability compared to DMEM. There was no significant difference in cell viability, at any of three dilutions, between CSC compositions and either MTA or Biodentine. Cytotoxicity was significantly lower for CSC compositions than for Vitrebond, DeTrey Zinc, Dycal, IRM, and 1% NaOCl, at all three dilutions, and undiluted Fuji II LC elute. In contrast to resin-modified glass ionomers, zinc phosphate cements, Dycal, and IRM, the CSC compositions showed no cytotoxic potential.

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  • Cornelia Frese, Diana Wolff, Tanja Krüger, Hans J. Staehle, Christophe ...
    Volume 60 (2018) Issue 1 Pages 89-96
    Released: March 24, 2018
    [Advance publication] Released: January 29, 2018
    JOURNALS FREE ACCESS

    Placement of composite resin restorations in deep subgingival cavities can damage surrounding soft tissues. In addition, commonly used resin-based composites (RBCs) might interfere with wound healing and periodontal health. To clarify cellular interactions with RBCs, we used an MTT assay to investigate adhesion of primary human gingival fibroblasts and human osteoblasts (hFOB 1.19) on five RBC materials with and without surface modifications (alumina blasting with 50- or 110-μm Al2O3). In addition, high-performance liquid chromatography (HPLC) was used to determine release of resin monomers from RBCs after 1 h, 1 day, and 7 days. As compared with tissue culture plastics (the control), cellular adhesion was significantly lower (P < 0.001) for human gingival fibroblasts and osteoblasts. Only minor, nonsignificant differences between individual RBCs were identified. HPLC analyses identified the release of three bifunctional methacrylates bisphenol A glycerolate dimethacrylate, triethylene glycol dimethacrylate, and diurethane dimethacrylate from RBCs and showed that monomer release increased between 1 h and 1 day but remained low. The present findings suggest that surface adhesion in the subgingival area is limited for the tested RBCs. Although residual monomer release was low for all tested RBCs, it might be sufficient to adversely affect cell adhesion.

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  • Liana F. Brito, Zuila A. Taboza, Virginia R. Silveira, Flavia A. Furla ...
    Volume 60 (2018) Issue 1 Pages 97-104
    Released: March 24, 2018
    JOURNALS FREE ACCESS

    The purpose of this cross-sectional study was to evaluate the occurrence of bilateral symmetry in the distribution of clinical parameters in subjects with generalized aggressive periodontitis (GAP) and severe chronic periodontitis (SCP). The sample comprised 53 subjects with GAP and 33 with SCP. Probing depth (PD) and clinical attachment loss (CAL) were recorded from both buccal and lingual interproximal sites of incisors and molars. The symmetry of periodontal destruction was analyzed in terms of intraclass coefficient correlations (ICC) for pairs of contralateral sites at which PD and/or CAL was ≥5 mm at one of the sites of the subjects in each group. GAP patients had a higher proportion of both PD and CAL ≥ 5 mm and also a higher mean proportion of subjects having PD and/or CAL ≥ 5 mm at one or both sites. The GAP group had 20 pairs of contralateral sites with PD (ICC = 0.22-0.63) and 26 pairs with CAL (ICC = 0.20-0.63), the correlation being statistically significant, while the SCP group had only 2 pairs (ICC = 0.36-0.48) with PD and 5 pairs with CAL (ICC = 0.33-0.58) showing a significant correlation. It can be concluded that GAP shows more symmetric periodontal destruction than SCP.

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  • Mine Ö. Tonguç, Selma Ünal, Rabia B. Arpaci
    Volume 60 (2018) Issue 1 Pages 105-114
    Released: March 24, 2018
    JOURNALS FREE ACCESS

    The purpose of the present study was to evaluate periodontal health status in children with sickle cell disease (SCD). Forty-nine children with SCD and 39 systemically healthy sex- and age-matched children were enrolled in the study. Plaque index, gingival index, bleeding on probing, pocket depth, salivary volume, and hyperplastic index were recorded. In addition, the histopathological evaluation of gingiva was made in a child with SCD. There were significant differences between the groups with regard to hyperplastic index (P < 0.05), whereas there were no differences in other parameters. Gingival enlargement was detected in 27 children (55.1%) in the SCD group and 6 children (15.4%) in the control group (P < 0.001). However, there were no differences in periodontal health status of children in the SCD and control groups, the most important finding of this study that the gingival enlargement was more prevalent in children with SCD. Sickling and chronic inflammation seen in SCD may affect gingival tissues. Therefore, physicians and dentists must be aware of the effects of SCD on gingival tissues.

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  • Zohaib Akram, Abdulaziz A. Al-Kheraif, Sergio V. Kellesarian, Fahim Vo ...
    Volume 60 (2018) Issue 1 Pages 115-120
    Released: March 24, 2018
    JOURNALS FREE ACCESS

    The aim of the present cohort study was to compare oral carriage of Candida in waterpipe smokers (WS), cigarette smokers (CS), and non-smokers (NS). A total of 141 individuals (46 WS, 45 CS, and 50 NS) were included. A questionnaire was used to gather demographic information and data on the daily frequency and duration of smoking habits, the reasons for smoking, and daily oral hygiene maintenance habits. Oral Candida (C.) samples were cultured and yeast species were identified using polymerase chain reaction. Unstimulated whole salivary flow rate (UWSFR) was also recorded. The numbers of missing teeth (MT) were counted and tongue lesions were clinically identified. C. albicans was the most prevalent yeast species isolated from all groups. Oral C. albicans carriage was higher among WS (P < 0.05) and CS (P < 0.05) than among NS. Oral C. tropicalis carriage, age, UWSFR and the number of MT were comparable among the groups. Oral Candida carriage was significantly higher among WS and CS than among NS. Therefore it appears that WS and CS are at an increased risk of developing oral candida infections.

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  • Olivier Lavigne, Anh M. Vu, Lindsay Richards, Zonghan Xie
    Volume 60 (2018) Issue 1 Pages 121-128
    Released: March 24, 2018
    JOURNALS FREE ACCESS

    The aim of this study was to determine whether recovery of mineral levels restored the mechanical properties of dentin subjected to different durations of demineralization. Dentin at the floor of class 1 cavities (n = 12) was demineralized for 1, 2, and 3 weeks. Half the demineralized cavity floor was coated (control side), and a Fuji IX restoration was placed. The remaining half was therefore in contact with the Fuji IX restoration (test side). Simulated dentin tubular fluid was then supplied to each pulp chamber for 6 weeks. After remineralization, the teeth were detached from the system and sectioned. Concentrations of calcium, phosphorus, fluorine, and strontium and mechanical properties (hardness and Young’s modulus) of the test and control sides were determined by electron probe microanalysis and nano-indentation, respectively. For remineralized dentin demineralized for 1 week, the substantial uptake of mineral elements restored hardness and Young’s modulus at depths of 50 to 200 μm from the lesion front. For longer periods of demineralization (2 and 3 weeks), structural damage to the demineralized dentin was severe and impeded recovery of mechanical properties, despite mineral uptake.

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  • Ayako Teranaka, Kiyoshi Tomiyama, Katsura Ohashi, Kaori Miyake, Tota S ...
    Volume 60 (2018) Issue 1 Pages 129-136
    Released: March 24, 2018
    [Advance publication] Released: November 22, 2017
    JOURNALS FREE ACCESS

    We used a polymicrobial (PM) biofilm model to examine associations of bacterial adhesiveness with surface characteristics of various dental materials. Four types of dental materials (apatite pellet, zirconia, ceramic, and composite resin) with rough and mirror surfaces were used. Surface roughness, surface free energy, zeta potential, and colony-forming units (CFUs) of the biofilm formations were measured. Biofilms were cultured for 24 h under anaerobic conditions, plated onto blood agar medium, and anaerobically cultured for 4 days. After culturing, CFU per mm2 was calculated, and samples were observed under a scanning electron microscope. Means and standard deviations of the experimental data were estimated, and one-way ANOVA and Tukey multiple comparison assays were performed. Pearson correlation coefficients were obtained for the CFU and surface characteristics. Surface roughness and surface free energy appeared to affect generation of PM biofilms on oral materials, and zeta potential was involved in generation of PM biofilms on mirror-ground oral materials.

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  • Kunihiko Sawada, Toshihiko Amemiya, Shigenori Hirai, Yusuke Hayashi, T ...
    Volume 60 (2018) Issue 1 Pages 137-141
    Released: March 24, 2018
    JOURNALS FREE ACCESS

    We compared the diagnostic reliability of 3.0-T magnetic resonance imaging (MRI) for detection of osseous abnormalities of the temporomandibular joint (TMJ) with that of the gold standard, cone-beam computed tomography (CBCT). Fifty-six TMJs were imaged with CBCT and MRI, and images of condyles and fossae were independently assessed for the presence of osseous abnormalities. The accuracy, sensitivity, and specificity of 3.0-T MRI were 0.88, 1.0, and 0.73, respectively, in condyle evaluation and 0.91, 0.75, and 0.95 in fossa evaluation. The McNemar test showed no significant difference (P > 0.05) between MRI and CBCT in the evaluation of osseous abnormalities in condyles and fossae. The present results indicate that 3.0-T MRI is equal to CBCT in the diagnostic evaluation of osseous abnormalities of the mandibular condyle.

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  • Hani M. Nassar, Reem Ajaj, Fatin Hasanain
    Volume 60 (2018) Issue 1 Pages 142-146
    Released: March 24, 2018
    JOURNALS FREE ACCESS

    The light intensity of a light-curing unit is a crucial factor that affects the clinical longevity of resin composites. This study aimed to investigate the efficiency of light-curing units in use at a local governmental dental school for curing conventional and bulk-fill resin materials. A total of 166 light-curing units at three locations were examined, and the brand, type, clinic location, diameter of curing tip, tip cleanliness (using a visual score), and the output (in mW/cm2 using a digital radiometer) were recorded. Only 23.5% of the units examined had clean tips, with the graduate student clinical area containing the highest percentage of clean tips. Further, tips with poor cleanliness score values were associated with significantly lower output intensities. A small percentage (9.4%) of units was capable of producing intensities higher than 1,200 mW/cm2 and lower than 600 mW/cm2 (7.6%). The majority of the low intensity units were located in the undergraduate student area, which also contained the highest number of units with intensities between 900 and 1,200 mW/cm2. The output of all the units in service was satisfactory for curing conventional resin composites, and most units were capable of curing bulk-fill resin materials.

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  • Wakako Miyama, Yasuki Uchida, Mitsuru Motoyoshi, Keiko Motozawa, Moeko ...
    Volume 60 (2018) Issue 1 Pages 147-153
    Released: March 24, 2018
    JOURNALS FREE ACCESS

    This study examined the relationship of vertical and horizontal changes in the alveolar bone crest with upper incisor movement after orthodontic treatment. Tooth movement was measured on lateral cephalograms. Vertical and horizontal changes in the median alveolar crest and distance from the cementoenamel junction and anterior nasal spine to the alveolar crest were measured with cone-beam computed tomography. The incisal edge moved distally, and the cervical point intruded significantly and moved distally. The median alveolar crest decreased by 3.80 ± 2.05 mm. The distance from the labial cementoenamel increased significantly, by 0.35 ± 0.38 mm. The vertical distance from the anterior nasal spine decreased significantly, and the alveolar crest moved distally. Vertical tooth movement was positively associated with change in the distance from the labial cementoenamel junction and inversely associated with vertical change in the distance from the anterior nasal spine on the labial and palatal sides. Lingual tooth movement was positively and negatively correlated with horizontal changes in the labial and palatal alveolar crest and vertical change in the palatal alveolar crest. The lingual movement of incisors was related to labial bone resorption. Greater lingual and extrusive movement of incisors led to a greater decrease in the alveolar bone crest.

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  • Hiroto Gunge, Yoichiro Ogino, Masafumi Kihara, Yoshihiro Tsukiyama, Ki ...
    Volume 60 (2018) Issue 1 Pages 154-158
    Released: March 24, 2018
    [Advance publication] Released: December 28, 2017
    JOURNALS FREE ACCESS

    This retrospective study analyzed clinical outcomes of monolithic zirconia restorations (MZRs) and factors related to restoration success. Patient records were searched to identify those provided MZRs (Cercon ht) for premolars or molars between April 2012 and March 2016. All MZRs were placed according to a standardized protocol. Kaplan-Meier analysis was used to assess MZR performance and failure after recall appointments at 1 year or later. In total, 101 patients received 148 MZRs. Mean duration of follow-up was 25.0 ± 9.9 months. Six MZRs required replacement: three because of pulpal complications, one because of root fracture of an abutment tooth, one because of restoration fracture, and one because the tooth was used as an abutment tooth for a fixed partial denture after root fracture of an adjacent tooth. The cumulative MZR survival (success) rate at 3.5 years was 91.5% (95% confidence interval, 82.1% to 100%). The findings of this short-term retrospective study indicate that posterior MZRs are a therapeutic option for certain patients. In addition, several clinical procedures contribute to MZR success, including preparation design and occlusal and adhesive surface treatments.

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Case Report
  • Noritaka Ohga, Jun Sato, Takuya Asaka, Masahiro Morimoto, Yutaka Yamaz ...
    Volume 60 (2018) Issue 1 Pages 159-162
    Released: March 24, 2018
    JOURNALS FREE ACCESS

    We report a case of osteonecrosis of the jaw (ONJ) associated with denosumab therapy in a 62-year-old female patient being treated for bone metastases from breast cancer. Upon initial presentation at the Department of Oral Medicine, Hokkaido University Hospital, the patient’s mandibular molar teeth were extracted because of severe periodontal disease. Two months later, epithelialization of the sockets was observed and treatment with anti-resorptive drugs was started for bone metastases. One year after tooth extraction, bone exposure in the right lower first molar region was observed, and stage 2 medication-related ONJ (MRONJ) was diagnosed. Up to this time, the patient had received zoledronic acid twice and denosumab 22 times. Denosumab was discontinued by the oncologist, and oral antibiotics with rinsing of the exposed bone area were prescribed. By 36 weeks after discontinuation of denosumab, a sequestrum in the posterior part of the mandible was naturally shed, and the site was healed. Bisphosphonate is deposited in bones, whereas denosumab functions extracellularly and circulates in the blood. The effect of denosumab on bone remodeling is reversed shortly after the drug has been discontinued.

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Erratum
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