The apical third of most root canals shows some degree of curvature, which is important in cleaning/shaping and obturation during root canal treatment. The present study evaluated the effect of master cone size on the apical seal of severely curved root canals. Thirty-eight mesial roots of human mandibular first molars were prepared using the crown-down technique. All samples were mature roots with closed apices, had no carious lesions or resorption, and had a canal curvature of > 45º to 60º. Two samples were used as a negative and positive control to evaluate the fluid filtration equipment, and the remaining 36 samples were equally divided into groups A, B, and C based on master cone size, namely, gutta-percha #20, #25, and #30, respectively. The fluid filtration method was used to evaluate microleakage. No significant difference in microleakage was observed among groups (P = 0.31). In conclusion, an increase in master cone size up to #30 does not significantly influence apical microleakage.(J Oral Sci 55, 93-98, 2013)

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Alcohol exposure alters oral mucosa. Patient compliance with mouthwash use may be reduced by oral pain resulting from rinsing with alcohol-containing mouthwash. However, information regarding the effects of alcohol consumption and mouthwash alcohol concentration on oral pain is limited. In this double-blind, randomized, controlled cross-over study, we investigated the effects of alcohol consumption status and mouthwash alcohol concentration on response to and perception of oral pain induced by alcohol-containing mouthwash. Fifty healthy men aged 33 to 56 years were enrolled and classified as drinkers and nondrinkers according to self-reported alcohol consumption. All subjects rinsed with two commercially available mouthwash products (which contained high and low concentrations of alcohol) and a negative control, in randomized order. Time of onset of oral pain, time of cessation of oral pain (after mouthwash expectoration), and pain duration were recorded, and oral pain intensity was recorded on a verbal rating scale. Drinkers had later oral pain onset and lower pain intensity. High-alcohol mouthwash was associated with earlier pain onset and greater pain intensity. In addition, oral pain cessation was later and pain duration was longer in nondrinkers rinsing with high-alcohol mouthwash. In conclusion, alcohol consumption status and mouthwash alcohol concentration were associated with onset and intensity of oral pain. (J Oral Sci 55, 99-105, 2013)

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Previous studies have demonstrated that nasal administration of the outer membrane protein of Porphyromonas gingivalis (40k-OMP) with cholera toxin (CT) as an adjuvant elicits protective immune responses against P. gingivalis in young mice. In the present study, we investigated whether administration of 40k-OMP plus CT would also induce 40k-OMP-specific antibody (Ab) responses to provide protective immunity against P. gingivalis infection in aged mice. Nasal immunization with 40k-OMP plus CT elicited 40k-OMP-specific IgG and IgA Ab responses in serum and a significant anti-40k-OMP IgA Ab response in nasal washes and saliva in 1- and 2-year-old mice. Furthermore, both Th1- and Th2-type cytokine responses were induced by the immunization, and cytokine-associated IgG1, IgG2a, and IgG2b Ab responses were observed in the spleens of aged mice. Although the aged mice showed lower 40k-OMP-specific Ab responses than young mice, their mucosal IgA Ab titers as well as serum IgG Ab responses indicated a retained ability to mediate protective immunity; the only exception was saliva in 2-year-old mice. These findings suggest that nasal immunization with 40k-OMP plus CT can be a potential vaccination strategy for eliciting levels of Abs sufficient to provide protective immunity against P. gingivalis infection in aged mice. (J Oral Sci 55, 107-114, 2013)

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Ammonium hexafluorosilicate (AHF) has been applied to arrest caries without discoloration. The purpose of this study was to observe structural and elemental changes of demineralized and AHF applied primary tooth enamel. Enamel from the labial surface of 20 primary canines was divided into an unground side and ground side at the center of the tooth, and demineralized with 35% phosphoric acid for 6 min. The teeth were divided into 4 groups according to a 3-min application of AHF and 1 week of soaking in artificial saliva, as follows: group A (neither AHF nor saliva), group B (only saliva), group C (only AHF), and group D (AHF and saliva), and then subdivided according to whether the enamel was ground or unground. Specimens were analyzed with scanning electron microscopy (SEM) and energy dispersive X-ray spectrometry (EDS). The data were statistically analyzed using ANOVA and Fisher's PLSD test at α = 0.05. In groups A and B, prism structures were seen, however, in groups C and D, enamel surfaces were covered with spherical particles. Ca/P ratio was significantly higher in groups C and D than in groups A and B. There was no significant difference between ground and unground enamel in the content of any element. The values for F, Na, Mg and Si persents and Ca/P ratio were significantly higher for the enamel surface than for points 10-30 µm beneath the surface. Results of this study suggest the possibility that AHF treatment arrests caries, although further study will be required to confirm this result. (J Oral Sci 55, 115-121, 2013)

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The aims of this study were to develop a Sudanese-Arabic version of the English-language Oral Health Impact Profile-14 (OHIP-14), assess the psychometric properties and performance of this new instrument, and then use it to investigate the impacts of selected oral disorders on oral health-related quality of life (OHRQoL). Sudanese adolescents and adults (age, ≥ 16 years; 781 males and 1107 females) attending outpatient clinics in Khartoum State were enrolled. The OHIP-14 was adapted, and the validity and reliability of the Sudanese-Arabic version of the questionnaire (OHIP-14s-ar) were assessed. The OHIP-14s-ar was then used to measure OHRQoL. Pearson correlation coefficients and multivariate analysis were used to examine relationships between OHRQoL and characteristics ascertained by interviews and clinical examinations. The OHIP-14s-ar had suitable construct validity, reliability, and internal consistency (i.e., Cronbach α). More than half of the participants reported that oral disorders affected quality of life; psychological discomfort and physical pain were the most frequently reported oral health impacts. Our results suggest that being female, tooth decay, systemic illness, and dry mouth worsen OHRQoL. The oral disorder with the greatest impact was dental caries, and tooth condition seemed to be more important than absence of teeth. The OHIP-14s-ar yielded convincing psychometric data, and its performance makes it a suitable measure for future cross-sectional and longitudinal studies in Sudan. (J Oral Sci 55, 123-132, 2013)

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The aim of this study was to evaluate the concentrations of calcium (Ca), inorganic phosphate (P_i) and fluoride (F) in carious dentin and in different layers of sound dentin. The samples examined were 52 permanent teeth (26 sound and 26 carious), which were subjected to two experiments to assess the mineral content of: 1) two layers (internal and external) of sound dentin and 2) sound and carious dentin. Ca and P_i were analyzed using a colorimetric method with arsenazo III (C22H18As2N4O14S2) and molybdate reagents, and F was analyzed using a specific electrode. A non-parametric test, the Mann-Whitney test, was used to verify differences between groups. Sound dentin showed a higher concentration of fluoride in the internal layer than in the external layer (P = 0.03), but no inter-layer differences in Ca or P_i concentration were evident. Lower concentrations of Ca, P_i and F were observed in carious dentin than in sound dentin (P < 0.05). The results of this study suggest that the internal layer of sound dentin has a higher fluoride content than the external layer, and that carious dentin has lower concentrations of Ca, P_i and F than sound dentin. (J Oral Sci 55, 133-137, 2013)

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Salivary flow rate, immunoglobulin, and periodontal status were affected during a simulated Skylab mission. The effect is more prominent after long-duration space flights and can persist for several weeks after landing. The objective of this study was to determine the effect of a simulated Mars environment on periodontal status and levels of salivary microorganisms and immunoglobulins in the human oral cavity. Twelve healthy male volunteers were studied before, at 1 and 2 weeks, and after completion of a mission in an isolated, confined simulated Mars environment at the Mars Desert Research Station, USA. We conducted a current stress test, measured salivary immunoglobulin, cortisol, α-amylase, salivary flow rate, and levels of plaque and salivary microbes, and assessed clinical periodontal parameters (probing depth, bleeding on probing, and clinical loss of attachment). Salivary IgG levels and Streptococcus mutans activity were significantly higher at 1 week. Values for clinical periodontal parameters (probing depth, bleeding on probing, and clinical loss of attachment) significantly differed at 1 week. Stress might be caused by the difficulty of the mission rather than the isolated environment, as mission duration was quite short. Periodontal condition might worsen due to poor oral hygiene during the mission. The present findings show that all periodontal conditions and levels of oral bacteria and stress after completion of the simulated Mars mission differed from those at baseline. To verify the relationship between stress status and periodontal health in simulated Mars missions, future studies using larger patient samples and longer follow-up will be required. (J Oral Sci 55, 139-143, 2013)

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Drug-resistant opportunistic infections may cause health problems in immunocompromised hosts. Representative microorganisms in opportunistic infections of the oral cavity are Staphylococcus aureus, Pseudomonas aeruginosa, and Candida albicans. We investigated the prevalence of drug-resistant opportunistic microorganisms in elderly adults receiving follow-up examinations after primary treatment of oral cancer. Oral microorganisms were collected from patients satisfactorily treated for oral cancer (defined as good outcomes to date) and a group of healthy adults (controls). After identification of microorganisms, the prevalence of drug-resistant microorganisms was studied. Pulsed-field gel electrophoresis (PFGE) and staphylococcal cassette chromosome mec (SCCmec) typing were also performed for methicillin-resistant S aureus (MRSA). Statistical analysis revealed no significant differences in the prevalences of the three microorganisms between the groups. Surprisingly, 69.2% of S aureus isolates showed oxacillin resistance, suggesting that MRSA colonization is increasing among older Japanese. These MRSA isolates possessed SCCmec types II and IV but no representative toxin genes. Our results indicate that a basic infection control strategy, including standard precautions against MRSA, is important for elderly adults, particularly after treatment for oral cancer. (J Oral Sci 55, 145-155, 2013)

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The present study aimed to assess the presence and level of colonization of Candida in patients with oral mucosal lesions, to determine the presence or absence of candidal hyphae in biopsy specimens and to correlate the degree of epithelial dysplasia with the number of colony-forming units of Candida. We performed a prospective study including 50 patients diagnosed as having oral potentially malignant and malignant disorders. These patients had lesions such as leukoplakia, lichen planus, lichenoid reaction, verrucous carcinoma and oral squamous cell carcinoma. An oral swish with 10 mL of normal saline was performed, and this was collected in a sterile plastic container. Candidal colony-forming units were assessed in the specimen. This was followed by a biopsy of the lesion, which was sent for histopathologic examination for dysplasia and severity, and to assess the presence or absence of candidal hyphae. The results of the present study revealed a correlation between higher Candida colonization and increasing severity of dysplasia. An effort was made to correlate Candida by histologic and mycologic means with epithelial dysplasia. If such a correlation is strongly established, then the importance of antimycotic therapy can be emphasized to avoid deterioration. (J Oral Sci 55, 157-160, 2013)

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Preformed crowns for restoration of primary teeth are used in various treatments and are essential for restoring the crowns of primary molars. However, there are concerns that mechanical, chemical, and thermal stimulation may cause release of components of such crowns. We examined systemic accumulation of heavy metals associated with preformed crowns (3M Stainless Steel Primary Molar Crowns) used in primary tooth restoration. The participants were 37 children who had visited the Pediatric Dental Clinic of Tsurumi University Dental Hospital. They were divided into two groups: 22 participants without a history of being fitted with a preformed crown for primary tooth restoration (controls), and 15 participants with preformed crowns for primary tooth restoration. Analysis of hair samples showed a significant difference in the level of the trace element Cr - an important component of the preformed crowns - between children with and without preformed crowns, but no significant differences in Fe or Ni levels. Levels of the trace elements Ni, Cr, and Fe were within allowable ranges, indicating that these minerals were not likely to be harmful. (J Oral Sci 55, 161-165, 2013)

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Despite a body of compelling evidence pertaining to the root canal accessibility of primary teeth, the number of referrals for inaccessibility of primary molars is considerable. The aim of the present study was to evaluate the prevalence of true and false primary molar inaccessibility among subjects who had been referred by general and pediatric dentists. We examined 199 primary molars in 156 patients (87 males, 69 females) aged 3-7 years who were referred by 215 general and 35 pediatric dentists. Problems related to inaccessibility were recorded for each tooth and any individual canal. One hundred seventy-five inaccessible teeth (87.9%) were successfully rehabilitated to accessible status (P < 0.001). The most frequent cause of inaccessibility was an inappropriate access cavity (42.3%), followed by difficult canals (32.6%) and orifice calcification (25.2%). The tooth most frequently reported as inaccessible was the maxillary first molar (40.2%), and that least frequently reported was the mandibular second molar (11.6%). The distobuccal canal of the maxillary first molar and the mesiolingual canal of the mandibular first molar were the most commonly inaccessible canals (P < 0.001). Only 1 out of 8 teeth referred as inaccessible was truly inaccessible. It seems that root canal inaccessibility is mostly attributable to lack of expertise among individual practitioners. (J Oral Sci 55, 167-173, 2013)

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The aim of this study was to evaluate different approaches to deactivating myofascial trigger points (MTPs). Twenty-one women with bilateral MTPs in the masseter muscle were randomly divided into three groups: laser therapy, needle treatment and control. Treatment effectiveness was evaluated after four sessions with intervals ranging between 48 and 72 h. Quantitative and qualitative methods were used to measure pain perception/sensation. The Wilcoxon test based on results expressed on a visual analog scale (VAS) demonstrated a significant (P < 0.05) decrease in pain only in the laser and needle treatments groups, although a significant increase in the pressure pain threshold was evident only for needling with anesthetic injection (P = 0.0469), and laser therapy at a dose of 4 J/cm² (P = 0.0156). Based on these results, it was concluded that four sessions of needling with 2% lidocaine injection with intervals between 48 and 72 h without a vasoconstrictor, or laser therapy at a dose of 4 J/cm², are effective for deactivation of MTPs. (J Oral Sci 55, 175-181, 2013)

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Invasive cervical root resorption is a relatively uncommon form of external root resorption. Creeping attachment is defined as postoperative coronal migration of the gingival margin. We describe a case of invasive cervical root resorption following coronal shift of interdental papillae 15 years after modified Widman flap surgery. (J Oral Sci 55, 183-185, 2013)

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Vertical root fracture is a frequent complication in endodontically treated teeth and usually leads to extraction of the affected tooth. Differential diagnosis may be difficult, especially in patients with periodontal and endodontic disease. This case report describes the diagnosis and clinical and radiographic features of apical periodontitis and vertical root fracture of the same tooth, which were separated by an interval of several years. Vertical root fracture of the mesial root was diagnosed with the help of an exploratory flap and microscopic observation. (J Oral Sci 55, 187-190, 2013)

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