Differential diagnosis between calcifying odontogenic cyst and adenomatoid odontogenic tumor by computed tomography images.

OBJECTIVES: Calcifying odontogenic cysts (COC) and adenomatoid odontogenic tumors (AOT) have similar radiographic findings. We examined the radiographic and computed tomography (CT) images of patients histologically diagnosed with COC or AOT and identified their characteristic findings. METHODS: The subjects included 12 patients histologically diagnosed with COC or AOT (one female and five males per group), who underwent CT at our hospital between Nov 1998 and Jun 2019. The location of the lesion, impacted tooth, bone expansion, root resorption, tooth migration, calcified body, and presence or absence of a high-intensity zone in the marginal area of the lesion were examined. RESULTS: In patients with COC, five patients with COC exhibited bone expansion toward the buccal side. The lesion encompassing the crown was attached to the cement-enamel junction and contained a radiopaque lesion with a calcified body. In 6 patients with COC, irregularly shaped calcified bodies were observed with small tooth-like structures. In patients with AOT, all six patients with AOT exhibited bone expansion toward the buccal and lingual sides. The lesion encompasses a part of the tooth root or the entire tooth. Punctate calcification was observed within the lesion and the marginal area in three patients, and a high-intensity zone was observed in the marginal area of the lesion in two patients. CONCLUSION: We report imaging findings that may be characteristic of COC and AOT, suggesting that CT findings may be useful for differentiating between COC and AOT.

A case of venous malformation of the mandible.

OBJECTIVE: Vascular malformations occur more rarely in bones than in soft tissue, with 0.5-1.0% of all intraosseous tumors occurring in the mandible. We report a diagnostically challenging case of unilocular venous malformation of the mandible. CASE REPORT: A 76-year-old man presented with a heterogeneous, unilocular, radiolucent lesion with a well-defined border. Panoramic radiography and computed tomography imaging revealed a continuous white line on the cortical bone at the inferior border of the left mandibular molar region. A spherical lesion with a well-defined border and a clear round region in the left mandible were revealed on magnetic resonance imaging. The lesion had the same signal intensity as muscles on T1-weighted imaging, a homogeneous high-intensity signal on short T1-inversion recovery imaging, and a well-defined low-signal intensity region surrounded by a high-intensity signal region on T2-weighted imaging. Pathological findings indicated that the lesion was a venous malformation. DISCUSSION: Although many studies have reported that venous malformations have a multilocular appearance, few have described the occurrence of unilocular lesions. Future investigations using magnetic resonance imaging and computed tomography are needed to increase the diagnostic accuracy for unilocular central vascular malformations of the jaw bone.

Quantitative measurements of the articular areas of mandibular condyles with temporomandibular joint disorders using magnetic resonance imaging.

OBJECTIVE: The authors sought to clarify the variation in the condylar anterior functional surface (AFS) of patients with temporomandibular joint (TMJ) disorders using quantitative measurements by magnetic resonance imaging (MRI). METHODS: MR images of 68 joints (2 males, 32 females) were used. The subjects were classified into three groups: with/without defects of cortical bone groups and a combination group without defects. The AFS was measured as the length between the protrusive point and the apex of the condyle on MRI (4-mm-thick slices), and the quad value of the length was defined as the area on the slice. The summed quad values of all slices were used as the AFS area. Differences in the areas among the three groups were compared by one-way analysis of variance (ANOVA). RESULTS: The non-defect group had significantly larger AFS areas than the defect group. CONCLUSIONS: Quantitative measurement on MR images clarified the changes in the condylar sagittal appearance.

A survey of influence of work environment on temporomandibular disorders-related symptoms in Japan.

INTRODUCTION: This study aimed at identifying the factors that influence the incidence of temporomandibular disorders (TMD)-related symptoms (TRS) in a Japanese working population. METHODS: Our study subjects comprised of 1,969 employees from the same Japanese company. The subjects were assessed using a questionnaire that covered both TRS and the work environment. TRS were measured from 4 items on the questionnaire. The work environment factors recorded were the daily mean duration of personal computer use, driving, precise work, commuting, time spent at home before going to bed, sleeping, attending business meetings, and performing physical labor. Statistical analysis was performed using t-tests, Chi-square tests, and logistic regression analyses. A result with P < 0.05 was considered statistically significant. RESULTS: The median total score on the 4 items used to assess TRS was 5 (25% = 4, 75% = 7). Two groups were defined such that the participants scoring ≤7 were assigned to the low-TRS group and those scoring ≥8, to the high-TRS group. The high-TRS group constituted 22.6% of the subjects. Logistic regression analyses indicated that female gender and extended periods of computer use were significant contributors to the manifestation of TRS. CONCLUSION: This questionnaire-based study showed that gender and computer use time was associated with the prevalence of TRS in this working population. Thus, evaluation of ergonomics is suggested for TMD patients.

Influence of psychosocial factors and habitual behavior in temporomandibular disorder-related symptoms in a working population in Japan.

BACKGROUND: The symptoms of temporomandibular disorders (TMD) are directly influenced by numerous factors, and it is thought that additional factors exert indirect influences. However, the relationships between TMD-related symptoms (TRS) and these contributing factors are largely unknown. Thus, the goal of the present study was to investigate influences on TRS in a working population by determining the prevalence of TRS, analyzing contributing factors, and determining their relative influences on TRS. MATERIALS AND METHODS: The study subjects were 2203 adults who worked for a single company. Subjects completed a questionnaire assessing TRS, psychosocial factors (stress, anxiety, depressed mood, and chronic fatigue), tooth-contacting habit, and sleep bruxism-related morning symptoms, using a 5-point numeric rating scale. Our analysis proceeded in 2 phases. First, all variables of the descriptor were divided into parts by using an exploratory factor analysis. Second, this factorial structure was verified by using a confirmatory factor analysis with structural equation modeling. RESULTS: Of 2203 employees, 362 reported experiencing TRS (16.4%). Structural equation modeling generated a final model with a goodness of fit index of 0.991, an adjusted goodness of fit index of 0.984, and a root mean square error of approximately 0.021. These indices indicate a strong structural model. The standardized path coefficients for "habitual behavioral factors and TRS," "psychosocial factors and habitual behavioral factors," "psychosocial factors and TRS," and "gender and habitual behavior factors" were 0.48, 0.38, 0.14, and 0.18, respectively. CONCLUSIONS: Habitual behavioral factors exert a stronger effect on TRS than do psychosocial factors.

Changes in the lingual muscles of obese rats induced by high-fat diet feeding.

OBJECTIVE: To elucidate the influences of obesity on the properties and volume of lingual (genioglossus and geniohyoid) muscles in obese rats. METHODS: We analysed the accumulation of triacylglycerol and the diameter of myofibres in the lingual muscles using histochemistry, and the MyHC composition using real-time PCR in rats fed a high-fat diet for 10 weeks. In the genioglossus and geniohyoid muscles, the percentage of oil droplet areas in the obesity group were 3.6 and 2.5 times greater than those in the control group, respectively (p<0.025). The diameters of the slow myofibres in the genioglossus and geniohyoid muscles were approximately 20% greater in the obesity group than in the control group (p<0.0001), while that of the fast myofibres in the geniohyoid muscle was approximately 10% greater in the obesity group than in the control group (p<0.0001). No significant difference in the expressions of any of the MyHC isoforms studied was found in any of the muscles studied between the obesity and control groups. CONCLUSION: High-fat diet feeding induced the fat deposition in the myofibre and influenced the structure of the lingual (genioglossus and geniohyoid) muscles.

Comparison of occlusal discomfort in patients with temporomandibular disorders between myofascial pain and disc displacement.

We compared occlusal discomfort in patients with temporomandibular disorders (TMD) between myofascial pain (MFP) and disc displacement (DD) using a database created from Sep, 2003 to Aug, 2005. We selected 71 patients with MFP and 170 patients with DD to construct a null model of structural equation modeling (SEM) in which anxiety influenced depressive mood, depressive mood aggravated occlusal discomfort and sleep complaints, and sleep complaints or an onset event caused by another person aggravated occlusal discomfort. We performed a simultaneous analysis of patients with MFP and DD. The estimated parameter of the path from depressive mood to occlusal discomfort was significant for patients with MFP, but not for patients with DD. The path from an onset event caused by another person, such as dental treatment to occlusal discomfort was significant in patients with MFP and those with DD. The Goodness of Fit Index (=0.909), The Adjusted Goodness of Fit Index (=0.867), and The Root Mean Square Error of Approximation (=0.039) indicated good acceptability. These results suggested that an increase in depressive mood may aggravate occlusal discomfort in patients with MFP, and an onset event caused by another person, such as dental treatment, also may aggravate occlusal discomfort in patients with MFP and those with DD.

NGF and its receptors TrkA and p75NTR in the epithelium of oral lichen.

BACKGROUND: Nerve growth factor (NGF) can through its receptors TrkA and p75(NTR) convey signals for cell survival, differentiation and death. The aim of this study was to examine whether NGF can play a role in the pathology of oral lichen (OL). METHODS: Sections from biopsies taken from patients with erythematous (ERY) OL and from volunteers with normal oral mucosa (NOM) were immunostained with antibodies against NGF, proNGF, TrkA, phosphorylated Trk, p75(NTR) and phosphorylated Akt (pAkt) and expression of RNA coding for proNGF/NGF was investigated by in situ hybridization. RESULTS: Both in ERY OL and NOM, cytoplasmic staining for NGF was seen in granular and upper spinous cell layers of the epithelium, whereas proNGF staining was seen in all epithelial cell layers. In situ hybridization showed that the proNGF protein was produced in the same cell layers. In OL, strong cytoplasmic stainings for TrkA and activated Trk (pTrk) were observed in all epithelial cell layers while these stainings were only weak in NOM. Basal keratinocytes in OL showed no or only weak cytoplasmic staining for p75(NTR), but in NOM there was a clear cell membrane staining. In OL, strong cytoplasmic and intermittent nuclear staining for pAkt was observed in spinous, granular and superficial layers, while basal and parabasal keratinocytes were negative. This staining was weak or absent in the entire epithelium of NOM. CONCLUSIONS: TrkA upregulation and activation in OL is one of the pathways that can activate pAkt and thereby rescue epithelial cells from untimely cell death.

Teeth contacting habit as a contributing factor to chronic pain in patients with temporomandibular disorders.

Many different factors are known to cause and perpetuate the symptoms of temporomandibular disorders (TMD). However, the roles of parafunctional factors have not been clearly elucidated. We found one of these habits in the clinical setting. This parafunctional habit involves daily light touching of the upper and lower teeth, when the mouth is closed. We named this habit Teeth Contacting Habit (TCH). [OBJECTIVES] To investigate the following hypotheses: 1) TCH is associated with perpetuation of chronic pain of TMD patients; 2) TCH is associated with other behavioral factors. [METHODS] Two hundred and twenty-nine TMD outpatients with chronic pain were analyzed with multivariate logistic regression models. [RESULTS] TCH was found in 52.4% of patients. Patients with TCH and pain lasting for more than four months were less likely to experience improvements in pain at the first visit (OR = 1.944, p = 0.043). Other factors associated with TCH were as follows: unilateral chewing (OR = 2.802) and involvement in a precision job (OR = 2.195). [CONCLUSION] TCH can prolong TMD pain and is associated with other behavioral factors.

Difficulty of food intake in patients with temporomandibular disorders.

PURPOSE: Although patients with temporomandibular disorders (TMD) often report impaired eating, the features of food intake difficulty have rarely been estimated. This study compared subjective difficulty in 4 categories of food intake situations among 3 subgroups of TMD patients. MATERIALS AND METHODS: A total of 511 TMD patients (402 women, 109 men, mean age 36.4 +/- 15.4, range 12 to 82) participated in this study. Subjects were divided into 3 TMD subgroups: myofascial pain (MFP), disc displacement with/without reduction (DD), and arthralgia or osteoarthritis (Arth). Patients' level of food intake difficulty was assessed using a visual analogue scale (VAS) for 4 categories of food intake situations: difficulty in putting food into mouth (PUT), difficulty in biting off foods (BIT), difficulty in grinding down foods (GRD), and overall difficulty in consuming a meal (OAL). RESULTS: Nearly all patients (98.6%) exhibited food intake difficulty in at least 1 category. In the category of PUT, the DD group exhibited significantly more difficulty than the MFP and Arth groups (P < .048), and the Arth group had a higher VAS score than the MFP group (P = .030). With regard to BIT and GRD, there was no significant difference among the TMD subgroups. In OAL, the DD group showed more difficulty than the MFP group (P = .046). CONCLUSION: TMD patients experienced impaired food intake ability. In particular, the DD group experienced more difficulty than the MFP group. Concerns about types of food and food intake behavior for each TMD subtype should be taken into account in the management of TMD patients.

Development of a new questionnaire to assess pain-related limitations of daily functions in Japanese patients with temporomandibular disorders.

BACKGROUND: Various measures/scales have been used to assess oral health-related quality of life in patients with temporomandibular disorders (TMDs). However, there have been few reports on the validity of questionnaires, and even fewer assessments of their use in Japanese sociocultural conditions. OBJECTIVES: The objectives of the study were: (i) to develop and refine the number of questions concerning pain-related limitations of daily function in the TMD questionnaire (LDF-TMDQ, 13 items) in Japanese patients with TMD, (ii) to assess factor validity, and (iii) to determine convergent and discriminant validity of the LDF-TMDQ with the observed items within a multidimensional questionnaire. METHODS: Four hundred and fifty-six (85.9%) outpatients with TMD were enrolled. The subjects were allocated into two roughly equal groups--E-group (233) for exploratory factor analysis and C-group (223) for confirmatory factor analysis [structural equation modeling (SEM)]. RESULTS: The exploratory factor analysis extracted 10 items and three factors. SEM showed the revised model to accurately describe the relationships between the measured items. As to convergent validity, the factor 'limitation in executing a certain task' and 'limitation of mouth opening' showed significant correlations with the observed items within the multi-dimensional questionnaire. However, the factor 'limitation of sleeping', show no correlation with any item. As to discriminant validity, all three factors had correlation coefficients below 0.4 with the psychological scale, the personality scale, and the visual analog scale for pain intensity. CONCLUSION: The LDF-TMDQ was reduced from 13 items to 10. The factor validity of the LDF-TMDQ, and the construct validity of 'limitation in executing a certain task' and 'limitation of mouth opening' were confirmed, while that of 'limitation of sleeping' remains to be determined.

Relationship between sex, age, and the minimum thickness of the roof of the glenoid fossa in normal temporomandibular joints.

This autopsy study investigates the minimum thickness of the roof of the glenoid fossa of grossly normal temporomandibular joints (TMJ) and correlates this to gender and age. This study was based on 49 TMJ specimens collected from 26 male and 23 female cadavers whose mean age at death was 73.8 years (range=50-96). No information was available about TMJ symptoms before death. A digital micrometer was used to measure the minimum thickness of the glenoid fossae. Comparisons were made based on gender and age. The mean value for the minimum roof thickness of all joint specimens examined was 0.8 mm. Mean values for male and female specimens were 0.8 and 0.7 mm, respectively, which were not significantly different. In addition, no age-related differences were observed. The average thickness was 0.7 mm for individuals in their fifties, 0.8 mm for those in their sixties and seventies, 0.6 mm for those in their eighties, and 0.8 mm for individuals in their nineties. Although these data indicate that the minimum thickness of the glenoid fossa of the TMJ is not significantly correlated with sex or age in patients 50 years of age and older, they nonetheless provide additional information about normal TMJ anatomy, particularly with regard to our knowledge of joint remodeling and function in the disease and non-disease states. Thickness of the glenoid fossa has also been implicated as a factor in facial trauma involving superior displacement of the mandibular condyle into the middle cranial fossa. The thickness of the glenoid fossa is also of potential interest during surgeries involving the glenoid fossa, such as TMJ arthroplasty or joint reconstruction.

Dynamic multislice helical CT of ameloblastoma and odontogenic keratocyst: correlation between contrast enhancement and angiogenesis.

PURPOSE: The purpose of this study was to assess whether the enhancement characteristics of dynamic multislice helical CT (MS-CT) could help in the differential diagnosis of ameloblastomas and odontogenic keratocysts. The correlation between enhancement characteristics and immunohistochemical findings, especially with regard to angiogenesis, was also evaluated. METHOD: Dynamic MS-CT was performed in 13 consecutive patients (8 ameloblastoma cases and 5 odontogenic keratocyst cases). The percentage of density increase (Enh%) was measured in dynamic MS-CT images taken during the arterial phase, and microvessel density (MVD) was analyzed using immunohistochemical study with anti-CD31 antibody. The Mann-Whitney U test was used to evaluate the significance of the Enh% or the MVD values between lesion subtypes, and the Spearman correlation coefficient was used to evaluate the correlation between the Enh% and the MVD in ameloblastomas and odontogenic keratocysts. RESULTS: The Enh% in ameloblastomas was significantly higher than that of odontogenic keratocysts (P < 0.005). The MVD of ameloblastomas was also significantly higher than that of odontogenic keratocysts (P < 0.005). The Enh% values for ameloblastomas and odontogenic keratocysts were positively correlated with the respective MVD values (r = 0.92, P < or = 0.000). CONCLUSION: Dynamic MS-CT is useful tool for differentiating between ameloblastomas and odontogenic keratocysts on the basis of the contrast enhancement values of intratumoral vascularities during the arterial phase. Furthermore, the Enh% obtained by dynamic MS-CT is correlated with the MVD in ameloblastomas and odontogenic keratocysts.