Comparison of Aversion to Visual Dental Stimuli Between Patients and Dentists: A Preliminary Study.

Purpose: Fearful dental patients often cite various dental instruments or procedures as triggers for their dental fear. Thus, visual dental stimuli provoke anxiety. This preliminary study aimed to assess the level of aversion to visual stimuli in dental patients and compare it with that in dentists. Patients and Methods: A total of 43 dental patients (25 women, 18 men; average age, 29.9 ± 13.3 years; patient group) and 13 dentists (4 women, 9 men; average age, 28.2 ± 2.0 years; dentist group) were included. All participants had previously undergone dental treatment. The dental fear level was assessed using the self-reported Dental Fear Survey (DFS). Thirty-two images associated with dental treatment were prepared and classified into three categories: dental instruments, dental procedures, and the dental environment. All participants rated their level of disgust toward each image on a visual analog scale with scores ranging from 0 to 100. Results: In the patient group, the disgust ratings for tooth extraction, dental drilling, and local anesthesia were >60, which were significantly different from those in the dentist group (Mann-Whitney U-test, p<0.001, p=0.001, and p=0.001, respectively). The ranking order of the disgust ratings for the 32 images showed significant correlation between the patient and dentist groups (Spearman correlation coefficient, r=0.80, p<0.001). In the patient group, the disgust ratings for dental impressions and the interdental brush, dental light, and dental chair were significantly correlated with DFS scores (r=0.61, p<0.001; r=0.47, p=0.001; r=0.41, p=0.006; and r=0.40, p=0.008, respectively). Conclusion: This study revealed that patients have more negative feelings toward invasive procedures than dentists. However, a significant correlation was identified between the ranking of aversion-provoking dental stimuli by patients and dentists. Furthermore, the level of aversion to several dental-related items that do not cause pain was correlated with the dental fear level.

Cerebral activation caused by dental sounds: a functional magnetic resonance imaging study.

Dental drilling sounds can induce anxiety in some patients. This study aimed to use functional magnetic resonance imaging (fMRI) to assess the relationship between dental fear and auditory stimuli. Thirty-four right-handed individuals (21 women and 13 men; average age, 31.2 years) were selected. The level of dental fear was assessed using the dental fear survey (DFS). Based on a threshold DFS score > 52, participants were categorized into two groups: dental fear (DF) group (n = 12) and control group (n = 22). Two types of stimuli were presented in a single session: dental and neutral sounds. Cerebral activation during the presentation of these sounds was evaluated using contrast-enhanced blood oxygenation level-dependent fMRI. In the DF group, dental sounds induced significantly stronger activation in the left inferior frontal gyrus and left caudate nucleus (one-sample t test, P < 0.001). In contrast, in the control group, significantly stronger activation was observed in the bilateral Heschl's gyri and left middle frontal gyrus (one-sample t test, P < 0.001). Additionally, a two-sample t test revealed that dental sounds induced a significantly stronger activation in the left caudate nucleus in the DF group than in the control group (P < 0.005). These findings suggest that the cerebral activation pattern in individuals with DF differs from that in controls. Increased activation of subcortical regions may be associated with sound memory during dental treatment.

Reliability of mixed dentition space analysis using a digital model obtained from an optical impression: a preliminary study.

OBJECTIVE: While mixed dentition space analysis is a common practice in pediatric dentistry, digital models created using an intraoral scanner are not as widely used in clinical settings. This preliminary study used a very small sample size with one reference model and aimed to (1) compare the accuracy of mixed dentition space analysis using a digital model obtained from an optical impression with that of conventional plaster model-based analysis and (2) assess inter-examiner differences. RESULTS: The space required for the mandibular permanent canine and premolars and arch length discrepancy were calculated using each model. The largest significant difference between plaster- and digital model-based analyses was identified when the right arch length discrepancy was considered (-0.49 mm; 95% confidence interval: -0.95-0.03); however, the value was considered clinically insignificant. Significant inter-examiner differences were observed for six items of the plaster model; however, no such differences were observed when using the digital model. In conclusion, digital model space analysis may have the same level of accuracy as conventional plaster model analysis and likely results in smaller inter-examiner differences than plaster model analysis.

Effect of aromatherapy with peppermint essential oil on the gag reflex: a randomized, placebo-controlled, single-blind, crossover study.

BACKGROUND: Sensitive gag reflexes prevent dental patients from receiving appropriate treatment. Aromatherapy helps patients relax during dental procedures. However, the effect of aromatherapy on the gag reflex caused by the stimulation of the oral cavity is unknown. This study aimed to evaluate whether aromatherapy reduces gag reflexes during oral stimulation. METHODS: In this randomized, placebo-controlled, single-blind, crossover study, the gag reflexes of 24 healthy individuals (12 females and 12 males; mean age: 34.3 ± 9.5 years) were quantified. A standard saliva ejector was slowly guided down the participant's throat to determine the maximum tolerance of the gag reflex, and the insertion distance was measured to quantify the gag reflex. All individuals participated in an aromatherapy session with peppermint essential oil and a placebo session with distilled water. The gag reflex was quantified before (baseline) and after each session. Another measurement was performed using nitrous oxide/oxygen inhalation as a positive control. RESULTS: Gag reflex values significantly increased after aromatherapy with both peppermint essential oil and placebo compared to baseline values (paired t-test, P < 0.001 and P = 0.014, respectively). The gag reflex value also increased significantly during nitrous oxide/oxygen inhalation (paired t-test, P < 0.001). There was no significant difference in the increase rate of gag reflex values between the positive control and aromatherapy interventions, but it was significantly lower after the placebo intervention (repeated measures analysis of variance, P = 0.003; post-hoc test, P = 0.83 and P = 0.02). CONCLUSION: Aromatherapy with peppermint essential oil has the potential for reducing gag reflex during dental procedures. TRIAL REGISTRATION: The study was registered in the University hospital Medical Information Network Clinical Trials Registry under the code UMIN000050616 (approved 17/03/2023).

Acupuncture and Transcutaneous Electrical Acupoint Stimulation Do Not Suppress Gag Reflex.

Objective: Gagging is a problem for many dental patients, as well as patients undergoing medical procedures, such as intubation. Research to date on the gag reflex has been limited by a lack of objective measures for measuring this reflex. Materials and Methods: A validated quantitative method was used to measure if acupuncture or transcutaneous electrical acupoint stimulation (TEAS) at Pericardium 6 (PC 6) and Stomach 36 (ST 36) suppressed the gag reflex, compared with a sham placebo. The subjects were 60 healthy adults randomly chosen to receive acupuncture, TEAS, or sham-TEAS on PC 6, located on the forearm, and ST 36, located on the lower leg. The gag reflex was measured by inserting a saliva ejector slowly down each participant's throat to determine the maximum tolerance of the gag reflex; the insertion length was used as an index of this reflex. Results: There was a significant difference in pre- and postintervention insertion lengths in all groups (paired t-test; all groups; P < 0.001). The differences in the insertion length among the groups (P = 0.76) and the interaction effect (group × time) were not significant (P = 0.79; 2-way analysis of variance). Conclusions: This study suggested that PC 6 and ST 36 stimulation was no different than placebo for alleviating the gag reflex.

Influence of artificial saliva contamination on adhesion in class V restorations.

This study aimed to evaluate the effects of artificial saliva contamination on a glass ionomer cement (GIC), a resin-modified GIC (RMGIC), and a composite resin (CR) that was used with two different etching adhesive systems. Three surface conditions were created on bovine teeth using artificial saliva: control (group I), mild saliva contamination (group II), and severe saliva contamination (group III). The microtensile bond strength (µTBS) of CR with dentin was significantly lower in group III than in group I. However, the µTBS of GIC and RMGIC with both enamel and dentin showed no significant intergroup differences. Moreover, CR exhibited significantly greater microleakage on cementum in group III than in group I, whereas both GIC and RMGIC showed no significant differences for both enamel and cementum. Thus, GIC and RMGIC may be suitable for preventing secondary caries after class V restorative treatments when contamination by saliva cannot be avoided.

Distribution of glutamate receptor, ionotropic, kainate 1 and neuropeptide calcitonin gene-related peptide mRNAs during formation of the embryonic and postnatal mouse molar in the maxilla.

The neuropeptide calcitonin gene-related peptide (CGRP) is a well-characterized neurotransmitter. Glutamate receptor, ionotropic, kainate 1 (Grik1) has also been demonstrated to generate high-affinity kainate receptors. However, little is known about the roles of CGRP and Grik1 during the developmental formation of teeth. In this study, we endeavoured to analyse the expression and localization of CGRP and Grik1 mRNAs using in situ hybridization on the mouse maxilla during development from the embryonic stage (E18.5) to after birth (P10, P15 and P20). We found that hybridization with an anti-sense probe for CGRP clearly localized in the maxilla at E18.5 in contrast to that of P15 and P20. Hybridization with an anti-sense probe for CGRP was not detected in the dental pulp of molars in the maxilla at P10, which is in contrast to Grik1 mRNA at the same developmental stage. Hybridization with an anti-sense probe for Grik1 mRNA was detected in the basal region of the dental pulp of molars at P10 and P15. Finally, these markers were not detected in molars in the mouse maxilla at P20. The ratio of positive cells for the hybridization signals of Grik1and CGRP in the dental pulp decreased from E18.5 (p<0.001). These features in CGRP and Grik1r mRNAs may indicate roles of function during tooth development between embryonic and postnatal stages with root formation and erupted movements.

Differences in the perception of dental sounds: a preliminary study.

PURPOSE: The sound of dental treatments can evoke anxiety in some dental patients. While women have shown greater dental anxiety than men, little is known about the gender differences in the perception of dental sounds. The purpose of this preliminary study was to evaluate differences in the perception of dental sounds according to the level of dental fear and gender. PATIENTS AND METHODS: Based on the level of dental fear, 69 adults (39 women, 30 men; average age, 28.1±8.1 years) were categorized into four groups. Three types of sounds were presented to participants: two sounds associated with dental treatment and a neutral sound. All participants rated their emotional reaction to each sound on a visual analog scale. RESULTS: Significant differences were observed for ratings of valence and disgust for a dental drilling sound among the four groups (p=0.007 and 0.004, respectively). Female participants in the dental fear group rated the dental drilling sound as more negative and disgusting than did female participants in the control group (p=0.002 for both ratings). However, no significant differences were found in ratings between males in the dental fear and control groups. CONCLUSION: Perception of dental sounds appears to differ by level of dental fear and by gender. Considering these differences may contribute to reducing fear in dental patients.

Gender differences in adolescents' perceptions toward dentists using the Japanese version of the dental beliefs survey: a cross-sectional survey.

BACKGROUND: While adult women show greater dental anxiety than adult men, few studies have examined gender differences in adolescent perceptions of dentists. Therefore, this cross-sectional study aimed to evaluate the gender differences in adolescents' perceptions toward dentists by using the Japanese version of the Dental Beliefs Survey (DBS) and the factor structure of the DBS. METHODS: We conducted surveys at schools, and 957 Japanese adolescents (403 girls and 554 boys, aged between 13 and 15 years) participated in this study. To assess their confidence in dentists, participants were asked to complete the self-reported, 15-item Japanese version of the DBS. We performed a Welch's t-test and a one-way analysis of variance to assess differences in DBS scores by gender and age. Factor analysis (principal components, varimax rotation) was used to assess the scale's factor structure. RESULTS: A significant gender difference was observed in the DBS scores (P = 0.018), suggesting that boys exhibit greater negative perceptions toward the behavior of dentists than girls. However, there was no significant difference found among ages. The factor analysis yielded two results: Factor 1, "trust" (seven items); and Factor 2, "lack of control" (five items). Notably, the factor structure differed according to gender. As such, by including only factors with eigenvalues above 1.0, the DBS for girls comprised "trust" (seven items) and "communication" (three items), while that for boys comprised "lack of control" (six items) and "belittlement" (six items). CONCLUSIONS: This study identified two factors of differing strengths pertaining to the confidence of Japanese adolescents in dentists. Gender differences in perceptions toward dentists were observed. Accounting for these differences may improve the effectiveness of strategies to lower dental anxiety and foster positive dental beliefs in young patients.

Reliability, validity, and sex differences in a quantitative gag reflex measurement method.

A reliable assessment method is required to manage the gag reflex. We tested the inter- and intra-examiner reliability and validity of a quantitative measurement method and evaluated the differences between sexes. This study included 21 healthy adults (10 women, 11 men; mean age, 27.1 ± 9.9 years). An examiner inserted a standard saliva ejector slowly down the participant's throat to determine the maximum tolerance of the gag reflex; the insertion depth was used as an index of gag reflex. The reflex was measured by one examiner during two sessions (S1 and S3) and by a second examiner during one session (S2) under the same conditions. The galvanic skin response (GSR) and heart rate (HR) were recorded during each session to test the method validity. Data were analysed using the intraclass correlation coefficient (ICC), paired t test, and two-way repeated-measures analysis of variance. The ICC of the gag reflex measurements was 0.91 between S1 and S2, and 0.93 between S1 and S3. The GSR and HR increased significantly after the maximum tolerance of the reflex in S1, S2, and S3 (GSR: P < 0.001, P = 0.004, P = 0.001, respectively; HR: all, P < 0.001). Differences in the measurements according to sex and session were not significant. Our method exhibited excellent inter- and intra-examiner reliability and was unaffected by the participants' sex. Measurement revealed significant autonomic reactivity, which is common for this reflex. Consequently, this method may be used in clinical and laboratory-based applications.

Comparison of the expression of neurotransmitter and muscular genesis markers in the postnatal male mouse masseter and trigeminal ganglion during development.

Calcitonin gene-related peptide (CGRP) is released by motor neurons and affects skeletal muscle fiber and transient receptor potential cation channel subfamily V member 1 (TRPV1), an important marker of pain modulation. However, the expression of CGRP and TRPV1 in the trigeminal ganglion (TG) during changes and in feeding patterns has not been described. We used real-time reverse transcription polymerase chain reaction and in situ hybridization to investigate the mRNA expression levels of CGRP and TRPV1 in the TG. The expression of myosin heavy-chain (MyHC) isoforms was also investigated in the masseter muscle (MM) during the transition from sucking to mastication, an important functional trigger for muscle. The mRNA and protein levels of CGRP increased in the MM and TG from postnatal day 10 (P10) to P20 in male mice. The protein levels of TRPV1 were almost constant in the TG from P10 to P20, in contrast to increases in the MM. The mRNA abundance of TRPV1 in the TG and MM was increased from P10 to P20. The localization of an antisense probe was used to count CGRP cell numbers and found to differentiate the ophthalmic, maxillary, and mandibular nerve divisions of the TG. In particular, the number of CGRP+ cells per 10,000 µm2 in the maxillary and mandibular divisions of the TG gradually changed from P10 to P20. The expression of CGRP and TRPV1 in the TG and MM and the patterns of expression of different MyHC isoforms were affected by changes in feeding during male mouse development.

Contribution of Streptococcus gordonii Hsa Adhesin to Biofilm Formation.

Adhesion of oral mitis group streptococci, such as Streptococcus gordonii, to acquired pellicle on the tooth surface is the first step in oral biofilm formation. S. gordonii strain DL1 possesses an Hsa adhesin, which recognizes the terminal sialic acid of host sialoglycoconjugates. The aim of the present study was to investigate the role of the Hsa adhesin in biofilm formation. The biofilm-forming ability of a S. gordonii hsa mutant on microtiter plates pre-coated with saliva, fetuin, or mucin was significantly lower than that of wild-type strain DL1. In contrast, no significant difference in biofilm-forming ability was observed in plates pre-coated with bovine serum albumin, which does not contain sialic acid. The biofilm-forming ability of strain DL1 in saliva-coated microtiter plates was also significantly reduced when the plate was pre-treated with neuraminidase. The sialic acid-dependent biofilm-forming ability of different wild-type S. gordonii strains varied. However, Southern and western blot analyses showed that all the tested wild-type strains possessed and expressed hsa homologs, respectively. These results indicate that the binding of Hsa adhesin to sialoglycoconjugates is associated with biofilm formation of S. gordonii DL1, and imply variation in the contribution of Hsa and its homologs to S. gordonii biofilm formation.

Local administration of resveratrol inhibits excitability of nociceptive wide-dynamic range neurons in rat trigeminal spinal nucleus caudalis.

Although we recently reported that intravenous administration of resveratrol suppresses trigeminal nociception, the precise peripheral effect of resveratrol on nociceptive and non-nociceptive mechanical stimulation-induced trigeminal neuron activity in vivo remains to be determined. The aim of the present study was to investigate whether local subcutaneous administration of resveratrol attenuates mechanical stimulation-induced excitability of trigeminal spinal nucleus caudalis (SpVc) neuron activity in rats, in vivo. Extracellular single-unit recordings were made of SpVc wide-dynamic range (WDR) neuron activity in response to orofacial mechanical stimulation in pentobarbital-anesthetized rats. Neurons responded to non-noxious and noxious mechanical stimulation applied to the orofacial skin. Local subcutaneous administration of resveratrol (1-10mM) into the orofacial skin dose dependently and significantly reduced the mean number of SpVc WDR neurons firing in response to both non-noxious and noxious mechanical stimuli, with the maximal inhibition of discharge frequency in response to both stimuli being seen within 5min. These inhibitory effects were no longer evident after approximately 20min. The mean magnitude of inhibition by resveratrol (10mM) of SpVc neuron discharge frequency was almost equal to that of the local anesthetic 1% lidocaine (37mM). These results suggest that local injection of resveratrol into the peripheral receptive field suppresses the excitability of SpVc neurons, possibly via inhibition of Na(+) channels in the nociceptive nerve terminals of trigeminal ganglion neurons. Therefore, local subcutaneous administration of resveratrol may provide relief of trigeminal nociceptive pain, without side effects, thus contributing to the suite of complementary and alternative medicines used as local anesthetic agents.

Jaw disorders in the pediatric population.

PURPOSE: This article will review the etiology, risk factors, history, and physical assessment of temporomandibular joint disorders (TMDs). In particular, this article discusses the role of the pediatric provider in diagnosing and beginning the initial treatment of TMDs, as well as the appropriate treatment plans. It also reveals some of the controversies regarding etiology and treatment of TMDs, as well as the paucity of research specific to TMDs in pediatrics. DATA SOURCES: A computerized search in PubMed and Ovid Medline, from 2006 to 2012, was conducted. A few seminal articles were included that were published before 2006. Hand searching was also performed, which included a few articles between 2012 and 2015. CONCLUSIONS: Although TMDs are mostly found in adults, it is also a finding in pediatrics, which increases in prevalence during adolescence. More research specific to pediatric patients with TMDs needs to be conducted so that pediatric-specific care can be provided. IMPLICATIONS FOR PRACTICE: TMD is a condition found in the pediatric population, and it is important for providers to take an adequate history and physical examination that incorporates the temporomandibular joint (TMJ) and muscles of mastication. It is also critical that providers begin initial education and management, followed by appropriate referrals.

Effects of surface reaction-type pre-reacted glass ionomer on oral biofilm formation of Streptococcus gordonii.

Streptococcus gordonii, a bacterium involved in the initial colonization of tooth surfaces, contributes to dental biofilm formation and is an important cause of infective endocarditis. This study aimed to investigate the influence of surface reaction-type pre-reacted glass ionomer (S-PRG) filler on oral bacterial growth and aggregation of S. gordonii. The effect of various concentrations of S-PRG eluate on the growth and the biofilm formation of S. gordonii and other oral microorganisms (Streptococcus mutans, Streptococcus oralis, Lactobacillus acidophilus, and Candida albicans) was assessed. In addition, the effect of S-PRG eluate on coaggregation of S. gordonii with both S. oralis and Fusobacterium nucleatum was assessed. The effect of S-PRG eluate treatment on autoaggregation of S. gordonii was also evaluated. Our results indicate that S-PRG eluate treatment reduced both for the growth and for biofilm of all organisms in a dose-dependent manner. Coaggregation of S. gordonii with both S. oralis and F. nucleatum was inhibited by S-PRG eluate, whereas autoaggregation of S. gordonii increased at certain concentrations of S-PRG eluate. These results indicate that the S-PRG filler possesses antimicrobial activity that is mediated by inhibiting growth and biofilm of oral microorganisms, and by suppressing coaggregation of S. gordonii. In addition, these findings indicate that coaggregation of S. gordonii with other bacteria is inhibited by increased autoaggregation of S. gordonii.

Cyclophosphamide-Induced Morphological Changes in Dental Root Development of ICR Mice.

BACKGROUND: Survivors of childhood cancer are at risk of late dental development. Cyclophosphamide is one of the most commonly used chemotherapeutic agents against cancer in children. The aim of this study was to investigate the effects of cyclophosphamide on root formation in the molars of growing mice and to assess the morphological changes in these roots using three-dimensional structural images. METHODS: We treated 16 12-day-old ICR mice with cyclophosphamide (100 mg/kg, i.p.) and 16 control mice with saline. At 16, 20, 24, and 27 days of age, the mandibular left first molars were scanned using soft micro-computed tomography. After scanning, the structural indices were calculated using a three-dimensional image analysis system, and the images were subjected to three-dimensional reconstruction. The length and apical foramen area of all distal roots were assessed. Histological changes in the apical region were then assessed via hematoxylin and eosin staining. RESULTS: The mandibular molars of all experimental mice showed evidence of cytotoxic injury, which appeared in the form of anomalous root shapes. Although all roots developed further after cyclophosphamide injection, the three-dimensional structural images showed that the roots in the experimental group tended to develop more slowly and were shorter than those in the control group. At 27 days of age, the mean root length was shorter in the experimental group than in the control group. Conversely, the apical foramen of the roots in the experimental group tended to close faster than that of roots in the control group. In addition, hematoxylin and eosin staining of the distal roots in the experimental group showed increased dentin thickness in the apical region. CONCLUSION: Our results suggest that cyclophosphamide can result in short root lengths and early apical foramen closure, eventually leading to V-shaped or thin roots.

Interaction effect between handedness and CNTNAP2 polymorphism (rs7794745 genotype) on voice-specific frontotemporal activity in healthy individuals: an fMRI study.

Recent neuroimaging studies have demonstrated that Contactin-associated protein-like2 (CNTNAP2) polymorphisms affect left-hemispheric function of language processing in healthy individuals, but no study has investigated the influence of these polymorphisms on right-hemispheric function involved in human voice perception. Further, although recent reports suggest that determination of handedness is influenced by genetic effect, the interaction effect between handedness and CNTNAP2 polymorphisms for brain activity in human voice perception and language processing has not been revealed. We aimed to investigate the interaction effect of handedness and CNTNAP2 polymorphisms in respect to brain function for human voice perception and language processing in healthy individuals. Brain function of 108 healthy volunteers (74 right-handed and 34 non-right-handed) was examined while they were passively listening to reverse sentences (rSEN), identifiable non-vocal sounds (SND), and sentences (SEN). Full factorial design analysis was calculated by using three factors: (1) rs7794745 (A/A or A/T), (2) rs2710102 [G/G or A carrier (A/G and A/A)], and (3) voice-specific response (rSEN or SND). The main effect of rs7794745 (A/A or A/T) was significantly revealed at the right middle frontal gyrus (MFG) and bilateral superior temporal gyrus (STG). This result suggests that rs7794745 genotype affects voice-specific brain function. Furthermore, interaction effect was significantly observed among MFG-STG activations by human voice perception, rs7794745 (A/A or A/T), and handedness. These results suggest that CNTNAP2 polymorphisms could be one of the important factors in the neural development related to vocal communication and language processing in both right-handed and non-right-handed healthy individuals.

Prevalence and association of self-reported anxiety, pain, and oral parafunctional habits with temporomandibular disorders in Japanese children and adolescents: a cross-sectional survey.

BACKGROUND: Associations between temporomandibular disorder (TMD) and psychological variables, pain conditions, and daily activities have been reported more commonly in middle-aged individuals than in children. However, to determine factor-specific preventive programs for TMD, it is important to evaluate the associations between multiple factors and TMD symptoms during childhood. The aim of this study was to assess the relationship between TMD symptoms and other orofacial pain conditions, daily activities, and trait anxiety in a population-based cross-sectional survey of Japanese children and adolescents. METHODS: A total of 1,415 subjects (11-15 years old) self-reported their TMD symptoms, headache, neck pain, and toothache, and completed questionnaire scales that assessed 15 daily activities. Trait anxiety was assessed using the State Trait Anxiety Inventory for Children-Trait (STAIC-T) scale. Subjects were dichotomized into a TMD group or control group, based on whether they reported at least 1 TMD symptom: the TMD group (≥1 TMD symptom, n = 182) and the control group (no TMD symptoms, n = 1,233). Data were analyzed using the chi-square test and multivariate logistic regression analysis. RESULTS: The prevalence rates for headache and neck pain were significantly higher in the TMD group than in the control group (44.0% vs. 24.7% and 54.4% vs. 30.0%, respectively; both P < 0.001). The odds ratios for TMD symptoms in subjects with neck pain and frequent diurnal clenching were 2.08 (P < 0.001) and 3.69 (P = 0.011), respectively. Moreover, high STAIC-T scores were weakly associated with TMD symptoms. CONCLUSIONS: In this young Japanese population, TMD symptoms were associated with other orofacial pain conditions, particularly neck pain, although they were only weakly associated with trait anxiety. Diurnal clenching was strongly associated with TMD symptoms. Health professionals should carefully consider these factors when developing appropriate management strategies for TMD in children and adolescents.

Cyclophosphamide inhibits root development of molar teeth in growing mice.

Root development of permanent teeth is disturbed in survivors of childhood cancer. Cyclophosphamide (CY) is a cytostatic drug commonly used for chemotherapy in children with cancer. This study aimed to evaluate the effects of CY on the development of molar teeth until the completion of occlusion in young mice, focusing on Hertwig's epithelial root sheath (HERS). We treated thirty-two 12-day-old ICR mice with CY (100 mg/kg; 100-CY group), and 36 control mice with saline. At 12, 14, 16, 20, 24, 27, 39, 60, and 76 days of age, the mandibular molars were removed. Soft X-ray radiographs were obtained in lateral projection. The root/crown length (R/C) ratio of the first molar was calculated. Serial sagittal sections were prepared and histomorphological hematoxylin and eosin (HE) staining and immunohistochemical (cytokeratin) studies were performed. The R/C ratio of the 100-CY group (0.78) was smaller than that of the control group (1.23) at 76 days (p < 0.05, t test). While all roots developed further after injection, microscopic examination showed that the roots of the first molars that developed in the 100-CY group were shorter than those in the control group. In addition, experimental mice showed apical closure of the roots. By 20 days after injection, the HERS had disappeared from the root surface in the 100-CY group. In conclusion, this study indicates that CY can induce a defect in HERS and cause early loss of HERS. Disruption of the epithelial sheath inhibits normal root formation, and it could cause irreversible short-root development.

Comparison of self-reported pain intensity, sleeping difficulty, and treatment outcomes of patients with myofascial temporomandibular disorders by age group: a prospective outcome study.

BACKGROUND: Subjective symptoms of temporomandibular disorders (TMDs) have rarely been studied by age group. We aimed to compare self-reported pain intensity, sleeping difficulty, and treatment outcomes of patients with myofascial TMDs among three age groups. METHODS: The study population included 179 consecutive patients (151 women and 28 men) who underwent comprehensive clinical examinations at a university-based orofacial pain center. They were classified into myofascial pain subgroups based on the Research Diagnostic Criteria for Temporomandibular Disorders. They were stratified by age group: M1, under 20 years; M2, 20-39 years; and M3, 40 years and older. The patients scored their pretreatment symptoms (first visit) and post-treatment symptoms (last visit) on a form composed of three items that assessed pain intensity and one item that assessed sleeping difficulty. Their treatment options (i.e., pharmacotherapy, physical therapy, and orthopedic appliances) and duration were recorded. All variables were compared between sexes in each group and between the age groups by using the Kruskal-Wallis test, the Mann-Whitney U test, the chi-square test, and analysis of variance (p < 0.05). RESULTS: No significant sex differences were found in any age group. Only sleeping difficulty was significantly different before treatment (p = 0.009). No significant differences were observed in the treatment options or treatment duration. After treatment, the intensity of jaw/face pain and headache and sleeping difficulty was significantly reduced in groups M2 and M3, but only the intensity of jaw/face pain was significantly decreased in group M1. The changes in the scores of pain intensity and sleeping difficulty were not different between the groups. CONCLUSIONS: Pain intensity does not differ by age group, but older patients with myofascial TMDs had greater sleeping difficulties. However, there were no differences between the age groups in the treatment outcomes. Clinicians should carefully consider the age-related characteristics of patients with myofascial TMDs when developing appropriate management strategies.