Odontoclastic root resorption is a significant clinical issue in relation to orthodontic tooth movement, and resorption of the roots of primary teeth is an intriguing biological phenomenon. The functional coordination of the OPG/RANKL/RANK system seems to contribute not only to alveolar remodeling, but also to resorption during orthodontic tooth movement and physiological root resorption. Serum OPG and s-RANKL are related to regulation of bone homeostasis by the OPG/RANKL/RANK system, and determination of their concentrations might be useful for predicting the rate of bone remodeling during orthodontic tooth movement, the net effect between bone remodeling and root resorption, and the degree of root resorption. It is therefore rational to speculate that a study of the levels of OPG and s-RANKL in blood and GCF, in relation to the degree of root resorption during orthodontic tooth movement, using healthy experimental animals and a carefully planned and organized experimental design, may be able to answer this intriguing question. (J. Oral Sci. 50, 367-376, 2008)

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Steroids have been found to be effective in treating symptomatic oral lichen planus (OLP) by reducing pain and inflammation. In fact, systemic corticosteroids should be reserved for acute exacerbation, and multiple or widespread lesions. They may be indicated in patients whose condition is unresponsive to topical steroids. However, various potent topical steroids have been reported to be effective in the treatment of symptomatic OLP. They can be used as the first line drugs in the treatment of OLP with no serious side-effects. During the therapy, candidiasis was commonly found and in addition, bad taste, nausea, dry mouth, sore throat and swollen mouth may occur as minor side-effects from some topical steroids. Because OLP is a chronic disorder that requires long-term treatment, topical steroids are recommended for the treatment OLP because of minimal side-effects and the cost benefit. This manuscript reviews the use of steroids, especially its topical application, in the treatment of OLP. (J. Oral Sci. 50, 377-385, 2008)

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The ability of serotonin 5-HT_1A and 5-HT_1B receptors in the ventrolateral striatum to modulate dopamine receptor-mediated jaw movements was investigated in freely moving rats, using a magnet-sensing system combined with an intracerebral drug microinjection technique. Apomorphine (1 mg/kg i.v.) has been found to elicit repetitive jaw movements. Bilateral injections of the 5-HT_1A receptor agonist 8-OH-DPAT (1 and 4 μg/0.2 μl in each side) into the ventrolateral striatum partially but significantly reduced apomorphine-induced repetitive jaw movements. The 5-HT_1A receptor antagonist WAY-100635 (1 μg), which alone did not affect the effects of apomorphine, antagonized the inhibitory effects of 8-OH-DPAT (4 μg). Bilateral injections of the 5-HT_1B receptor agonist CP93129 (1 and 10 μg) also reduced apomorphine-induced repetitive jaw movements in a dose-dependent manner. However, the 5-HT_1B receptor antagonist GR55562 (1 and 10 μg) did not antagonize the inhibitory effects of CP93129 (10 μg). These results suggest that 5-HT_1A, but not 5-HT_1B, receptors in the ventrolateral striatum play a modulatory role in the production of dopamine receptor-mediated jaw movements. (J. Oral Sci. 50, 387-395, 2008)

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The purpose of the present in vitro study was to compare the cytotoxic effect of two commercially available brands of mineral trioxide cement (ProRoot MTA and MTA Angelus), modified zinc oxide-eugenol cement (SuperEBA) and resin-modified glass ionomer cement (Vitrebond) using rat pulp cells (RPC-C2A) and human lung fibroblasts (MRC-5). The cells were cultured in typical culture conditions and exposed to the tested materials by adaptation of insert wells. The cytotoxic effect was recorded at two observation periods (24 and 72 h) by using a colorimetric assay of tetrazolium reduction (XTT method) in reference to controls. Overall, the degree of cytotoxic effect in ascending order was ProRoot MTA – MTA Angelus < SuperEBA < Vitrebond. Both MTA materials tested exerted mild suppression of cellular mitochondrial activity and may be characterized as biologically inert materials. (J. Oral Sci. 50, 397-402, 2008)

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The purpose of this study was to compare the 24-h composite-to-composite microtensile bond strength of Gradia Forte (GF) repaired with the same or a different material after different surface treatments. Different groups were set up, in which composite blocks of GF were subjected to the following treatments: Group 1, sandblasting with 50-μm aluminum oxide and 37% phosphoric acid etching (PA); Group 2, bur roughening and etching with 37% PA; Group 3, etching with 37% PA only. In all groups, a bonding resin was used as an intermediate agent prior to layering of the repair material (Gradia Direct (GD), Gradia (G), or GF). Bond strengths were then determined and analysed statistically. Scanning electron microscopy (SEM) evaluation of substrates and bonded interfaces was also performed. Surface treatment (P < 0.001) and repair materials (P < 0.001) were factors that significantly affected repair strength, whereas their interaction (P = 0.31) had no significant effect. Group 3 showed significantly superior repair strength to Groups 1 and 2, whereas Group 2 showed significantly weaker repair strength to Groups 1 and 3. Irrespective of surface treatment, GD and G gave similar results, which were better than those obtained using GF. The lowest probability of failure was found for GD and G in Group 3, whereas the highest was found for GF in Groups 1 and 2. Premature failures occurred mainly with G and GF. No pre-testing failures were found in the sandblasting/GD subgroup. Surface-treated composites showed different textures under SEM, whereas composite-repair bonds showed comparable interfacial features. (J. Oral Sci. 50, 403-412, 2008)

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Butyric acid is detected in periodontal pockets and is thought to be involved in the initiation and progression of periodontal disease. We examined the effects of sodium bicarbonate on the butyric acid-induced epithelial cell damage. The human gingival carcinoma cell line Ca9-22 was cultured in medium that contained butyric acid with or without sodium bicarbonate. The viability of cells treated with sodium bicarbonate was significantly higher than that of cells treated with butyric acid alone. The effects of butyric acid on ICAM-1 expression were significantly improved by sodium bicarbonate. Within the limitations of this in vitro study, sodium bicarbonate was indicated to be a useful therapeutic agent to reduce the butyric acid-induced periodontal tissue damage. (J. Oral Sci. 50, 413-417, 2008)

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Lactoferrin accelerates the differentiation of osteogenic and chondrogenic lineage cells, whereas it inhibits the myogenic and adipogenic differentiation of pluripotent mesenchymal cells; however, the effect of lactoferrin on the differentiation of preadipocytes is unknown. In this study, we examined the effect of lactoferrin on adipogenic differentiation using a mouse preadipocyte cell line, MC3T3-G2/PA6. The cells were cultured in differentiation medium with or without lactoferrin to induce cellular differentiation. The cell lineage was then determined by Oil Red O staining, real-time PCR screening for the mRNA expression of phenotype-specific markers, and Western blot analysis. The number of Oil Red O-positive lipid droplets decreased following treatment with lactoferrin, as did the mRNA expression of C/EBPα, PPARγ, aP2, and adiponectin. Furthermore, our Western blot data revealed a decrease in PPARγ expression attributable to lactoferrin exposure. These results suggest that lactoferrin suppresses the adipogenic differentiation of MC3T3-G2/PA6 cells. (J. Oral Sci. 50, 419-425, 2008)

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Previously, we showed that recombinant human bone morphogenetic protein-2 (rhBMP-2) increased bone augmentation beyond the skeletal envelope within a titanium cap in a rabbit calvarium; many cuboidal osteoblastic cells were observed histologically. These results suggested that the new osteoblastic cells might have differentiated and matured via stimulation by rhBMP-2. To date, however, no studies have reported the characteristics of osteoblastic cells derived from adult rabbit calvarium, after addition of rhBMP-2. To determine the effects of rhBMP-2 on osteoblastic cells, we observed morphological characteristics and alkaline phosphatase activity of osteoblastic cells from an adult rabbit calvarium. The expression of proteins in the BMP signaling pathway and extracellular matrix were analyzed, and mineralized nodule formation was assessed. The alkaline phosphatase activity increased significantly after rhBMP-2 stimulation. The protein levels of phosphorylated-Smad1, Runx2, osteocalcin, osteopontin, and type I collagen were augmented by rhBMP-2 stimulation using Western blotting or ELISA; rhBMP-2 also stimulated mineralized nodule formation with alizarin red staining. The results suggest that primary osteoblastic cells derived from a rabbit calvarium have osteogenetic characteristics in vitro, underscoring the potential use of these cells as a model for studying bone formation. These cells may play an important role in in vivo bone augmentation in a rabbit experimental model. (J. Oral Sci. 50, 427-434, 2008)

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The quality of apical seal with regard to the length of remaining gutta-percha following post-space preparation is still controversial. The purpose of this in vitro study was to compare three different lengths of remaining gutta-percha for apical seal after post-space preparation. A total of 126 single-rooted extracted maxillary human anterior teeth with intact apices, straight roots, and without resorption were used in this study. The root canals were prepared and filled with gutta-percha and AH26 sealer. The post-space preparation was accomplished. Ninety-six teeth were randomly divided into three groups (4, 5 and 6 mm of gutta-percha was retained in group 1, 2 and 3, respectively).Thirty teeth were considered for the control groups in which 5 teeth served as positive and 5 teeth served as negative controls. The specimens were placed in India ink for 48 hours and then divided into two halves. The amount of leakage was observed and measured with a stereomicroscope at × 16 magnification and 0.1 mm accuracy. The results showed that there were significant differences among the three experimental groups (P < 0.05). The best apical seal after post-space preparation was associated with the maximum length of remaining gutta-percha in the apical portion of the treated teeth. (J. Oral Sci. 50, 435-439, 2008)

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The aim of this study was to determine the effect of immersion disinfection procedures on the dimensional stability of two elastomeric impression materials. Impressions of a stainless steel die were made with polyether (PE) and with addition-polymerized silicone rubber (PVS). The test specimens underwent disinfection treatment by immersion in two commercially available solutions containing quaternary ammonium compounds (Sterigum Powder, SP) and glutaraldehyde plus an amino derivative (MD520, MD), respectively. The impressions were measured at 4 different time points: before any disinfection treatment (T0); after the first disinfection (T1); 6 hours after the first disinfection (T2); after the second disinfection, carried out 6 hours after the first one (T3). Impressions which were not disinfected served as controls. When both impression materials were disinfected with SP, significant differences were detected among all measurements (P < 0.0001), with the exception of T2 vs T3 (P > 0.05). On the other hand, when MD was used, significant differences were found when T0 measurement was compared to T1, T2 and T3 measurements (P = 0.0043 for PE, and P = 0.0014 for PVS). The dimensional change of all material/disinfectant combinations was always ≤0.5%. Therefore, the effects of immersion disinfection on the dimension of elastomers in SP or MD are not clinically relevant. (J. Oral Sci. 50, 441-446, 2008)

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The purpose of this study was to examine the simultaneous interrelationships of oral health behavior and oral health between mothers and their children using the linear structural relations (LISREL) program. The subjects comprised 117 pairs of mothers and their children aged between 8 and 11 years. Dental status was expressed as DMFT. The Oral Rating Index (ORI) for mothers and ORI for children (ORI-C) were used as measures of gingival health. Hiroshima University Dental Behavioral Inventory (HU-DBI) was used for the assessment of mothers' oral health behavior. HU-DBI had a direct positive relationship to ORI, a direct negative relationship to DFT, and a direct positive association with ORI-C. Toothbrushing had a direct negative relationship to ORI-C. The hypothesized model was found to be closely consistent with the data. These results indicate that the periodontal health status of mothers is directly related to the oral health status of their children, and that toothbrushing by children is directly related to their gingival health. (J. Oral Sci. 50, 447-452, 2008)

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Our aim was to translate the original English version of the Geriatric Oral Health Assessment Index (GOHAI) into Arabic and assess its validity and reliability for use among people in North Jordan. After translation into Arabic and back-translation to check the translation quality, a total of 288 participants completed the Arabic version of the GOHAI questionnaire. Individual GOHAI items were recoded and summed as originally recommended. The questionnaire sought information about socio-demographic characteristics and self-reported perception of general and oral health. Clinical examination included assessment of periodontal status, and number of decayed teeth, missing teeth, filled teeth and crowned teeth. Reliability, internal consistency, and concurrent, convergent and discriminant validity of GOHAI scores were examined. Mean GOHAI score was 40.9 (SD = 10.6, range: 12 to 60). Cronbach's alpha for the GOHAI score was 0.88, indicating a high degree of internal consistency and homogeneity between the GOHAI items. The test-retest correlation coefficient for add-GOHAI scores was 0.72, indicating good stability. Add-GOHAI scores increased with poorer perceived general and oral health. Convergent validity, construct validity and discriminant validity of the GOHAI were demonstrated. The Arabic translation of the GOHAI demonstrated acceptable validity and reliability when used for people in North Jordan. It could therefore be used as a valuable instrument for measuring oral health-related quality of life for people in this region. (J. Oral Sci. 50, 453-459, 2008)

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An elevated frequency of micronucleated exfoliated cells (MEC) in atrophic and erosive oral lichen planus (OLP) has been reported. To evaluate the effects of supplemental beta-carotene (BC) on MEC frequency in OLP lesions, we performed an open trial in 20 patients with atrophic and/or erosive OLP. Each patient received 15 mg of BC four times daily for 3 months. The frequency of MEC in both lesions and adjacent normal mucosa in each patient was evaluated and compared before and after supplementation. Serum levels of BC and retinol were also determined. After BC supplementation, all patients had higher levels of serum BC and retinol. The MEC frequency in OLP lesions was significantly reduced (P < 0.01). No significant changes were seen in the MEC frequency in adjacent normal mucosa. BC supplementation thus significantly reduces MEC frequency in atrophic and erosive OLP. (J. Oral Sci. 50, 461-467, 2008)

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The aim of this in vitro study was to assess the antibacterial effects of gray and white mineral trioxide aggregate (GMTA and WMTA), calcium hydroxide (CH), Portland cement (PC) and a new endodontic cement (NEC) on various species of microorganisms, using agar diffusion test. A base layer of Petri plates was made using Muller-Hinton agar. Five cavities were made in agar and filled with fresh mixed materials after 24 h. Pseudomonas aeruginosa, Enterococcus faecalis, Staphylococcus aureus, Escherichia coli and a mixture of these bacteria were seeded by pour plate. The plates were preincubated for 2 h at room temperature followed by incubation at 37°C. The inhibition zone diameters were measured at 24, 48 and 72 h. The highest mean diameters of growth inhibition zones were observed around NEC and CH. According to one-way ANOVA, there was a significant difference among test groups (P < 0.001), while post-hoc test revealed no significant difference between the mean zone diameters of NEC and CH, and also between MTAs and PC. However, there was a significant difference between CH and NEC in comparison with MTAs and PC groups (P < 0.001). It appears that NEC may act as a potent antibacterial agent similar to CH. (J. Oral Sci. 50, 469-474, 2008)

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The aim of this study was to measure the difference in the erosion depth of enamel measured by profilometry (PM) and a measuring microscope (MM). Sixty enamel specimens were divided into ten groups. Each specimen group was exposed to 50 ml of a carbonated drink with pH 2.38 or orange juice with pH 3.67 for 15, 30, 60, 120, and 180 minutes. Depths of eroded areas were measured with a profilometer and a measuring microscope. Data of average enamel loss were measured by PM and MM for all erosion times and were scatter plotted on a graph with regression fit. Correlations between the enamel loss measured by PM and MM were analyzed with a paired sample t-test to compare the discriminatory abilities of the two methods of analysis for all erosion times. The regression fit in all study cases showed a high linear relationship (R² = 0.90) between measurements by PM and MM, but in cases where the erosion depth was lower than the depth of focus (DOF) of the MM objective lens, there were weak correlation coefficients (-0.007 – 0.303) for comparison between the two measurement methods. (J. Oral Sci. 50, 475-479, 2008)

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The purpose of this study was to determine the elastic modulus of components at the resin-dentin interface with the use of an ultrasound device. Dentin slabs were obtained from freshly extracted bovine incisors shaped into a rectangular form. After demineralization, the dentin specimens were immersed in adhesives and polymerized. Adhesives were also polymerized and trimmed into the same shape as the dentin slabs. The specimens were then immersed in distilled water at 37°C for up to one year. The ultrasound equipment employed in this study was a Pulser-Receiver, transducers and an oscilloscope. By measuring the longitudinal and shear wave sound velocities, the elastic modulus was determined. When the elastic modulus of adhesive resin-infiltrated demineralized dentin was compared with that of adhesives, slightly but significantly lower values were found for adhesives used in a self-etching primer system. On the other hand, a higher elastic modulus was observed for resin-infiltrated dentin than for an adhesive used in an etch and rinse system. The elastic modulus of the resin-infiltrated dentin prepared with the etch and rinse system was affected by long-term storage in distilled water. (J. Oral Sci. 50, 481-486, 2008)

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Cervical external root resorption can be present in natural teeth, involving one or more teeth in the same patient. The incidence of these lesions appears random and the etiology remains unclear. Cervical external root resorption has been considered a difficult clinical situation, and its diagnosis and treatment of the defect challenging. The present report describes a case of multiple external cervical resorption lesions involving four teeth, including the history, and the clinical and radiographic findings. The treatment included surgical intervention and restoration of the defect without sacrificing the pulp. A 3-year re-evaluation of the case confirmed a stable, uneventful clinical recovery. (J. Oral Sci. 50, 487-491, 2008)

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Chromosome 6 deletions are very rare (1,2), and deletion 6q syndrome is clinically characterized by mental and/or neuromotor retardation and microcephaly (3). Other alterations frequently observed are decreased biparietal diameter, hypertelorism, hypotelorism, absent eyebrows, prominent eyes with ptosis, receding chin, dysmorphic ears, large extremities, prominent nasal bridge, long philtrum, epicthus, strabismus, and micrognathia (3-5). Laryngomalacia is the most common congenital laryngeal anomaly and the most frequent cause of stridor in infants (6-11). We report the case of a 14-year-old male patient with both deletion 6q syndrome and laryngomalacia, who we treated for multiple dental caries. He had a medical history of tracheotomy at age 11 years for laryngomalacia, and has suffered from epileptic attacks and aspiration pneumonia over the last 2 and 6 years, respectively. Since he was mentally retarded and in a poor respiratory state, dental treatment under general anesthesia was scheduled in our hospital. General anesthesia was induced and maintained using 30% nitrous oxide and 1-3% sevoflurane in oxygen through the tracheotomy tube. Pre- and intraoperative endotracheal suction improved the condition of both lungs markedly and the procedures were uneventful and completed in 2 h and 58 min. (J. Oral Sci. 50, 493-495, 2008)

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