The relationship between the uptake of alveolar bone inflammation and of cervical lymph nodes on FDG-PET.

OBJECTIVES: To elucidate the relationships between the maximum standardized uptake value (SUVmax) of alveolar bone and those of lymph nodes (LNs) around the neck on 18F-fluoro-2-deoxy-D-glucose (18F-FDG) positron emission tomography (PET). METHODS: The SUVmax values of alveolar bone and of level IA, level IB, and level IIA LNs of 174 patients, including those with and without active odontogenic inflammation, on PET/computed tomography (PET/CT) performed for a health check were retrospectively evaluated. The upper and lower jaws were divided into four blocks (right maxilla, left maxilla, right mandible, and left mandible). The SUVmax values of each block and of the LNs were calculated. The differences in the SUVmax of each LN level between patients with and without odontogenic inflammation, and the relationship between the SUVmax values of alveolar bone and of the LNs were analyzed statistically. RESULTS: Significant differences in SUVmax values of bilateral level IB and IIA LNs were found between patients with and without odontogenic inflammation (Mann-Whitney U test: right level IB, p = 0.008; left level IB, p = 0.006; right level IIA, p < 0.001; left level IIA, p = 0.002), but not in bilateral level IA LNs (Mann-Whitney U test: right level IA, p = 0.432; left level IA, p = 0.549). The inflammatory site with the highest SUVmax in level IB LNs was the ipsilateral mandible (multivariate analysis: right, beta = 0.398, p < 0.001; left, beta = 0.472, p < 0.001), and the highest SUVmax in level IIA LNs was the ipsilateral maxilla (multivariate analysis: right, beta = 0.223, p = 0.002; left, beta = 0.391, p < 0.001). CONCLUSIONS: The SUVmax values of level IB and IIA LNs were associated with a tendency toward a higher SUVmax value of alveolar bone on 18F-FDG-PET.

Correlation between the presence of tonsilloliths and the bone defects by periodontitis on imaging analysis: a pilot study.

BACKGROUND: Very recently, a significant relationship between tonsilloliths and dental plaque-related pathologies was reported using digital panoramic radiographs. Their dynamics over time suggest that tonsilloliths may be in a permanently active phase that functions to remove foreign matter. The aim of the study was to evaluate the relationship between the occurrence of tonsilloliths and the extent of periodontitis. METHODS: A total of 608 patients who underwent both CT and panoramic radiographs were included in the study. Both of two imaging were retrospectively and independently assessed with respect to the presence of tonsilloliths detected on CT and panoramic radiographs, and bone defects caused by periodontitis detected on panoramic radiographs. The type of retrospective study is case-control. Then, the differences between age groups were evaluated with respect to the degree of bone resorption and its correlation with the presence of tonsilloliths. The relationships between categorical variables were assessed using Pearson's correlation coefficient or Spearman's correlation coefficient. RESULTS: There was a significant relationship between tonsilloliths on CT and the extent of the bone defect on panoramic radiographs (Spearman's correlation coefficient, r = 0.648, p = 0.043). In addition, there was a significant difference in the extent of the bone defect caused by periodontitis between subjects with and without tonsilloliths in the 60 to 69-year-old group (Mann-Whitney U test, p = 0.025), 70 to 79-year-old group (Mann-Whitney U test, p = 0.002), and 80 to 89-year-old group (Mann-Whitney U test, p = 0.022), but not in other age groups (Mann-Whitney U test: under 9-year-old group, p = 1.000; 10 to 19-year-old group, p = 1.000; 20 to 29-year-old group, p = 0.854; 30 to 39-year-old group, p = 0.191, 40 to 49-year-old group, p = 0.749; 50 to 59-year-old group, p = 0.627; ≥90-year-old group, p = 1.000). CONCLUSIONS: The presence of tonsilloliths was related to the extent of periodontitis because the structures were responding dynamically.

Three Level Recognition Based on the Average of the Phase Differences in Physical Wireless Parameter Conversion Sensor Networks and Its Effect to Localization with RSSI.

In recent years, there have been increased demands for aggregating sensor information from several sensors owing to the spread of the Internet of Things (IoT). However, packet communication, which is a conventional multiple-access technology, is hindered by packet collisions owing to simultaneous access by sensors and waiting time to avoid packet collisions; this increases the aggregation time. The physical wireless parameter conversion sensor network (PhyC-SN) method, which transmits sensor information corresponding to the carrier wave frequency, facilitates the bulk collection of sensor information, thereby reducing the communication time and achieving a high aggregation success rate. However, when more than one sensor transmits the same frequency simultaneously, the estimation accuracy of the number of accessed sensors deteriorates significantly because of multipath fading. Thus, this study focuses on the phase fluctuation of the received signal caused by the frequency offset inherent to the sensor terminals. Consequently, a new feature for detecting collisions is proposed, which is a case in which two or more sensors transmit simultaneously. Furthermore, a method to identify the existence of 0, 1, 2, or more sensors is established. In addition, we demonstrate the effectiveness of PhyC-SNs in estimating the location of radio transmission sources by utilizing three patterns of 0, 1, and 2 or more transmitting sensors.

Changes in tonsillolith characteristics detected in a follow-up CT study.

BACKGROUND: Tonsilloliths are related clinically to halitosis and tonsillar abscess. However, the dynamics of tonsilloliths over time are unknown. The aim of the study was to evaluate change in the characteristics of tonsilloliths in a time-dependent fashion by follow-up computed tomography (CT). METHODS: Tonsilloliths were analyzed in 326 CT scan pair sets of initial and at least two follow-up CT examinations of patients with whole palatine tonsils and various diseases of the oral and maxillofacial regions. RESULTS: Over the follow-up period, 12.1% of tonsilloliths disappeared. Approximately 26.1% of tonsilloliths changed in size during follow-up, mostly increasing in size. In tonsilloliths that showed enlargement, the mean (± standard deviation) growth rate was 0.61 ± 0.41 mm per year. Approximately 37.3% of tonsilloliths changed position during the follow-up period; of these, movement was toward the respiratory tract in 92% at a mean rate of - 1.38 ± 1.59 mm per year. The calcification levels of almost all tonsilloliths showed dynamic change: HU number increased in 84.3% and decreased in 12.7% of tonsilloliths over the follow-up period. The mean rate of HU increase was 63.8 ± 96.3 HU/year, and the mean rate of HU decrease was - 38.4 ± 66.8 HU/year. CONCLUSIONS: The calcification levels of all tonsilloliths showed dynamic fluctuation, and a tendency for excretion of tonsilloliths from the body. Their dynamics over time suggest that tonsilloliths may be in a permanently active phase which functions to remove foreign matter.

Determining the optimal osteotomy distance with the fibula free flap in mandibular reconstruction.

OBJECTIVE: Fibula free tissue transfer is a common and reliable method for mandibular reconstruction. Functional outcomes from this procedure are dependent on the successful union of the osseous segments postoperatively. This study was conducted to define the maximum gap-size criteria for osseous union to occur at osteotomy sites in fibula free flap reconstruction of the mandible. STUDY DESIGN: Retrospective chart review. SETTING: Tertiary care academic center. SUBJECTS AND METHODS: A retrospective chart review of computed tomography and medical records was conducted on patients who underwent fibula free flap surgery and had imaging of the mandible at <3 months and >6 months after surgery. Distances between osteotomies were measured and evaluated for interval healing. Secondary data included subject age, sex, smoking status, diabetes, number of osteotomies, complications, and adjuvant therapy. RESULTS: Thirty-eight osteotomy sites were analyzed from thirteen subjects and a total of 190 measurements were made. The mean gap size at the first scan that demonstrated union by the second scan interval was 1.31 mm and mean gap size demonstrating non-union was 2.55 mm (p < 0.01). Complication rate, number of osetotomies, adjuvant therapy, or medical co-morbidities did not significantly affect rates of union. CONCLUSIONS: In this study, osseous union was achieved with a mean osteotomy gap size of 1.31 mm. The data suggests that distances between ossesous segments >2 .55mm have a higher risk of non-union. We believe the information from this study will help augment current and future techniques in the field of mandible reconstruction.

Identification and adjustment of experimental occlusal interference using functional magnetic resonance imaging.

BACKGROUND: The purpose of this study was to use functional magnetic resonance imaging (fMRI) to quantify changes in brain activity during experimental occlusal interference. METHODS: Fourteen healthy volunteers performed a rhythmical tapping occlusion task with experimental occlusal interference of the right molar tooth at 0 mm (no occlusion), 0.5 mm, and 0.75 mm. The blood-oxygen-level dependent (BOLD) signal was quantified using statistical parametric mapping and compared between rest periods and task periods. RESULTS: In tapping tasks with experimental occlusal interference of 0.75 mm or 0.5 mm, there was clear activation of the contralateral teeth-related primary sensory cortex and Brodmann's area 46. At 0 and 30 minutes after removal of the experimental occlusal interference, the activation clearly appeared in the bilateral teeth-related primary sensory cortices and Brodmann's area 46. At 60 minutes after the removal of the experimental occlusal interference, the activation of Brodmann's area 46 had disappeared, and only the bilateral teeth-related primary sensory cortices were active. CONCLUSIONS: The present results suggest that adjustments for experimental occlusal interference can be objectively evaluated using fMRI. We expect that this method of evaluating adjustments in occlusal interference, combined with fMRI and the tapping task, could be applied clinically in the future.

Imaging Characteristics of Embedded Tooth-Associated Cemento-Osseous Dysplasia by Retrospective Study.

BACKGROUND: Since there are many differential diagnoses for cemento-osseous dysplasia (COD), it is very difficult for dentists to avoid misdiagnosis. In particular, if COD is related to an embedded tooth, differential diagnosis is difficult. However, there have been no reports on the characteristics of the imaging findings of COD associated with embedded teeth. The aim of the present study was to investigate the occurrence and imaging characteristics of cemento-osseous dysplasia (COD) associated with embedded teeth, in order to appropriately diagnose COD with embedded teeth. METHODS: The radiographs with or without histological findings of 225 patients with COD were retrospectively analyzed. A retrospective search through the picture archiving and communication system (PACS) of the Division of Oral and Maxillofacial Radiology of Kyushu Dental University Hospital was performed to identify patients with COD between 2011 and 2022. RESULTS: Fifteen COD-associated embedded mandibular third molars were identified in 13 patients. All 13 patients were asymptomatic. On imaging, COD associated with embedded mandibular third molars appeared as masses that included calcifications around the apex of the tooth. On panoramic tomography, COD showed inconspicuous internal calcification similar to that of odontogenic cysts or simple bone cysts, especially in patients with COD only around the mandibular third molar region. Those with prominent calcification resembled cemento-ossifying fibroma, calcifying epithelial odontogenic tumor, calcifying odontogenic cyst, adenomatoid odontogenic tumor, and so on, as categories of masses that include calcifications on panoramic tomography and computed tomography. CONCLUSIONS: The current investigation is the first to report and analyze the imaging characteristics of COD associated with embedded teeth. It is important to consider the differences between COD and other cystic lesions on panoramic tomography, and the differences between COD and masses that include calcifications on CT.

Imaging characteristics of gubernaculum tracts in patients with cleidocranial dysplasia: a computed tomography study.

OBJECTIVES: To elucidate the imaging characteristics of the gubernaculum tract (GT) in patients with cleidocranial dysplasia (CCD) as visualized with computed tomography (CT). STUDY DESIGN: This was a retrospective analysis of the presence and shape of GTs of unerupted permanent teeth and supernumerary teeth on CT in 9 patients with CCD. RESULTS: The overall GT detection rate for unerupted permanent teeth was 83.5% (81/97), with no significant difference between permanent teeth without and with adjacent supernumerary teeth (P = .414). The overall GT detection rate for unerupted supernumerary teeth was 83.1% (49/59). Of the 156 total unerupted teeth analyzed, 83.3% (130/156) were judged to have GTs. No significant difference in detection rate of GTs was found between permanent and supernumerary teeth (P > 0.999). A composite morphology consisted of a single GT for a permanent unerupted tooth with 1 or 2 supernumerary teeth in which the dental follicles of the permanent and supernumerary teeth were confluent. In total, 44 groups consisted of 1 permanent and 1 or 2 supernumerary teeth; 79.5% (35/44) had GTs. CONCLUSIONS: A specific composite structure of GTs and dental follicles may signify that 2 or 3 teeth are derived from a single dental lamina in patients with CCD. In such cases, tooth eruption may fail due to the presence of only 1 GT for multiple teeth.

Comparison of the distribution of the Bartholin and/or Rivinus salivary ducts assessed with magnetic resonance-sialography in patients with ranula and in healthy subjects.

Background: The distribution and drainage of the sublingual gland ducts have various patterns that might be related to sublingual gland-related diseases, including ranula. This study aimed to elucidate the characteristics of the distribution of Bartholin and/or Rivinus ducts in patients with ranula using magnetic resonance (MR) sialography. Methods: In this retrospective cross-sectional study, the distributions and drainage patterns of sublingual gland ducts on MR sialography were classified in 74 subjects without sublingual gland-related disease as confirmed by both medical history and clinical examination and 15 patients with ranula, respectively. All patients had visited Kyushu Dental University Hospital from July 2015 to June 2022 to undergo MR imaging. Data on the distributions and drainage patterns of the sublingual gland ducts, including the characteristics of the Bartholin and/or Rivinus ducts, were then statistically compared between subjects without sublingual gland-related disease and patients with ranula. The images were assessed by an experienced oral and maxillofacial radiology specialist certified by the Japanese Society for Oral and Maxillofacial Radiology. The distributions (five groups) and drainage patterns (three patterns) of the sublingual gland ducts on MR sialography were classified in reference to previous studies, with some modifications in all subjects without sublingual gland-related disease and patients with ranula. Results: A significant difference in the distribution of the ducts (P<0.001), with a low number of patients exposing an undetected canal or Rivinius duct, was found in the group of patients with ranula (P<0.05). Regarding drainage patterns, no patient with ranula presented a Rivinius duct only. A significant difference in the drainage patterns of the sublingual gland ducts on MR sialography was observed between subjects without sublingual gland-related disease and patients with ranula (P=0.001). Conclusions: The present results suggest that the distribution of the sublingual gland ducts, mainly, the Bartholin duct, may be related to ranula formation. These findings also demonstrate that MR sialography contributes well to preoperative evaluation and is effective for assessing the complex excretory distribution of the sublingual gland ducts.

Prevalence and imaging characteristics of detectable tonsilloliths on 482 pairs of consecutive CT and panoramic radiographs.

BACKGROUND: Recent studies suggest that tonsilloliths are clinically related to halitosis and tonsillar abscess. Based on our empirical knowledge, tonsilloliths are relatively commonly encountered in daily clinical practice. It has been reported that the detection rate of tonsilloliths was under 24% in previous reports, although experience suggests otherwise. The purpose of the study was to evaluate the prevalence and characteristics of tonsilloliths using computed tomography (CT). In addition, the possible causes of low detection rates on panoramic radiographs were evaluated based on comparisons between CT images and panoramic radiographs in order to elucidate the limitations of visualizing the area around the palatine tonsils on panoramic radiographs. METHODS: 482 pairs of CT images and panoramic radiographs were retrospectively assessed with respect to the presence and characteristics of tonsilloliths. In addition, the causes in cases of disagreement between the two modalities were analyzed. RESULTS: The detection rate of tonsilloliths was 46.1% using CT scans, unlike previous reports. The characteristics of tonsillolith were dot-like figures with about 300-500 Hounsfield units within the palatine tonsil under the soft palate. The most common length of tonsilloliths was about 3 or 4 mm. As the subjects aged, the detection rate increased gradually. A significant difference in the tonsillolith detection rate was found between the over and under 40-year-old groups (p < 0.0001). However, the detection rate of tonsilloliths was only 7.3% on panoramic radiographs. A significant correlation was observed between the detection rate of tonsilloliths on panoramic radiographs and CT number (Spearman r = 0.429), size, (Spearman r = 0.318), and number of tonsilloliths (Spearman r = 0.333). CONCLUSION: The present results suggest that tonsilloliths are relatively more common than previously suggested. However, panoramic radiographs detect only a small percentage of palatine tonsilloliths. The low detection rates on panoramic radiographs might be related to the degree of calcification, size, and number of tonsilloliths.

Occurrence of silk stitch abscess after surgery in patients with oral squamous cell carcinoma.

OBJECTIVES: To elucidate the predisposing factors and clinical characteristics related to the occurrence of stitch abscess after surgery in patients with oral squamous cell carcinoma (SCC). PATIENTS AND METHODS: The subjects were 232 patients who underwent excision and/or reconstruction and/or neck dissection for oral SCC using silk sutures for high ligation of the blood vessels. Detection rates and characteristics of patients with stitch abscess were retrospectively evaluated by comparing patients with and without stitch abscesses after surgery diagnosed by ultrasonography and findings of various modalities in 232 patients. Several echogenic dots with subtle acoustic shadows in a hypoechoic mass were identified as the characteristic findings of stitch abscess on US. The patient groups with and without stitch abscess were compared with respect to various factors to identify those that predispose to the occurrence of stitch abscess. The factors analyzed included patients' sex and age, chemotherapy treatment, radiotherapy treatment, the presence of a history of allergy, and blood test results. RESULTS: A significant correlation was found between the occurrence of stitch abscess and age, liver function abnormalities on blood tests, and the presence of a history of allergy. Multiple stitch abscesses clearly tended to occur more often than single ones in patients with stitch abscess. CONCLUSIONS: The occurrence of stitch abscesses was related to age, liver dysfunction, and/or the presence of allergies. When diagnosing stitch abscess, the occurrence of multiple stitch abscesses is important.

Mash1 is required for the differentiation of AADC-positive type III cells in mouse taste buds.

Mash1 is expressed in subsets of neuronal precursors in both the central nervous system and the peripheral nervous system. However, involvement of Mash1 in taste cell differentiation has not previously been demonstrated. In this study, we investigated the role of Mash1 in regulating taste bud differentiation using Mash1 KO mice to begin to understand the mechanisms that regulate taste bud cell differentiation. We found that aromatic L-amino acid decarboxylase (AADC) cells were not evident in either the circumvallate papilla epithelia or in taste buds in the soft palates of Mash1 KO mice. However gustducin was expressed in taste buds in the soft palates of Mash1 KO mice. These results suggest that Mash1 plays an important role in regulating the expression of AADC in type III cells in taste buds, which supports the hypothesis that different taste bud cell types have progenitor cells that are specific to each cell type.

Visualization of Peripheral Blood Vessels on the Lingual Aspect of the Mandible Using a Balanced Steady-State Free-Precession Sequence with a Time-Spatial Labeling Inversion Pulse: Usefulness for Prevention of Severe Complications of Dental Implantation.

The aim of this study was to evaluate whether a balanced steady-state free-precession (SSFP) sequence with a time-spatial labeling inversion pulse (time-SLIP) without contrast medium could elucidate branches of the lingual and facial arteries on the lingual aspect of the mandible as a potential technique for preventing severe complications in dental implantation surgery. In this study, magnetic resonance angiography (MRA) using SSFP with a time-SLIP was evaluated in 40 subjects. The outline and course of branches of the lingual and facial arteries near the mandible were assessed clinically in the same subjects against contrast-enhanced computed tomography (CT) images as the gold standard. The submental, sublingual, and deep lingual arteries could be visualized via MRA in 16, 20, and 16 of the 40 subjects, respectively. The major axes of the respective arteries were approximately 24, 24, and 16 mm. The outline and course of all visualized arteries coincided with those on CT. MRA using SSFP with a time-SLIP appears to have potential as a non-contrast technique for visualizing branches of the lingual and facial arteries on the lingual aspect of the mandible. Information regarding the outline and course of these arteries as obtained using this MRA technique could assist in preventing severe complications in dental implantation surgery.

The Alteration of Brain Function by the Improvement of Periodontal Tissues and Occlusal State.

Objective: In this study, we have introduced a case in which the effective blood oxygenation level-dependent signal on functional magnetic resonance imaging (fMRI) was altered by the improvement of periodontal tissue and occlusal function in a patient with periodontitis Stage II Grade B. Material and Methods. A 61-year-old female patient requiring periodontal treatment was diagnosed as having periodontitis Stage II Grade B via clinical and radiographic examinations. Her past medical history included type 2 diabetes, hypertension, and hyperlipidemia. Following the patient's informed written consent, the periodontal initial treatment provided to the patient included tooth brushing instruction and scaling and root planing; however, occlusal adjustment was not performed at this stage. Occlusal force and fMRI results were also evaluated at the initial and reevaluation examinations. Results: After the periodontal initial treatment had been performed, it was noted that the patient's periodontal tissue and occlusal force had improved. It was also evident from fMRI that cerebral blood flow had been activated in the insula, primary motor cortex, and premotor cortex. Conclusion: This result suggested that the periodontal ligament had recovered and the periodontal ligament neuron had been further subjected to clenching in the insula so that the muscle spindle sensation impacted the motor cortex.

Imaging characteristics of the gubernaculum tracts in successional teeth related to deciduous fused teeth on computed tomography.

The purpose of this study was to elucidate the imaging characteristics of the gubernaculum tracts in successional teeth related to fused deciduous teeth on computed tomography. The imaging findings of 15 gubernaculum tracts in successional teeth related to fused deciduous teeth were retrospectively analyzed using cone-beam computed tomography or multidetector computed tomography. In cases without a congenitally defected successor, the two gubernaculum tracts of two successional teeth related to fused deciduous teeth were fused into one. Gubernaculum tracts (GTs) in mesial successors were vertical, but in distal successors they were inclined to mesial. The major abnormalities of the successional teeth related to fused deciduous teeth were delayed eruption and delayed formation. No inclined mesial successors were found, whereas most of the distal successors were inclined to mesial along with the inclined GT. The gubernaculum tracts of successors with a congenital defect of the other successors were vertical, and such successors had no abnormalities. The present study showed the imaging characteristics of gubernaculum tracts in successional teeth related to fused deciduous teeth. The abnormal eruption of successional teeth related to fused deciduous teeth may be associated with the characteristics of their gubernaculum tracts.

Differential expression of the glucose transporters in mouse gustatory papillae.

Taste receptors and their downstream signaling molecules are activated by sugars and sweeteners in the gut and participate in the regulation of glucose transport into enterocytes. The glucose transporter families GLUT and SGLT are responsible for the absorption of glucose, GLUT4 and SGLT1 being expressed preferentially in T1R3-positive taste cells. However, the expression patterns of the other glucose transporters in mouse gustatory tissues have not yet been elucidated. Therefore, we have examined the expression patterns of the glucose transporters (GLUT1-4 and SGLT1-3) in mouse gustatory tissues. Reverse transcription/polymerase chain reaction assays have revealed that GLUT1, 3, and 4 and SGLT1 mRNAs are expressed in the circumvallate papillae. Immunohistochemical analysis has shown that SGLT1 is expressed in a subset of the epithelial cells: from the basal cell layer to the prickle cell layer and in intragemmal and extragemmal epithelium cells in the circumvallate, foliate, and fungiform papillae. GLUT1, GLUT3, and GLUT4 are expressed in the prickle cell layers and/or basal cell layers in these papillae. Moreover, GLUT1, but not GLUT3 or GLUT4, is expressed in a subset of intragemmal and extragemmal epithelium cells in these papillae. Double-labeling experiments have demonstrated that GLUT1-positive taste bud cells coexpress gustducin and inositol 1,4,5-triphosphate receptor type III. These results suggest that SGLT1 and GLUT1 play a role in glucose-sensing and/or transport in mouse taste buds.

Importance of magnetic resonance imaging for evaluation of a child with prominent swelling of the facial region after trauma: report of a case.

In the present case of a 9-year-old girl with prominent swelling in the mental and facial regions after trauma, repeated magnetic resonance (MR) examinations were performed to evaluate areas of incision, because the swelling became worse and more prominent despite intravenous antibiotic treatment. However, there was no evidence of respiratory tract impingement or deformation, including obliteration, on MR imaging. Therefore, surgical treatment involving an incision because of facial region swelling was cancelled, and the intravenous antibiotic therapy was continued. To prevent misdiagnosis and over-treatment of young children with inflammation of the oral and maxillofacial regions, dentists, including pediatric dentists, should be aware of the clinical usefulness of MR examinations. In particular, MR examinations are non-invasive for young children, because there is no X-ray exposure, and they can be used repetitively. At the same time, the present case demonstrated that it is very difficult to understand and predict changes in the inflammation process associated with children's facial trauma.

Depth of invasion determined by magnetic resonance imaging in tongue cancer can be a predictor of cervical lymph node metastasis.

OBJECTIVES: We evaluated the relationships between depth of invasion (DOI) of tongue cancer, as measured with preoperative T1- and T2-weighted magnetic resonance imaging (MRI) and postoperative histopathologic (Path) specimens, with cervical lymph node metastasis (CLNM) and tumor stage. We also calculated the correlation of MRI and Path DOI measurements. STUDY DESIGN: This retrospective study included 101 patients who had squamous cell carcinoma of the tongue and were treated surgically. Two observers measured DOI on all 3 modalities. RESULTS: DOI thresholds for predicting CLNM with high diagnostic efficacy were 6.99 mm and 8.32 mm for MRI and 5 mm for Path. DOI values from all modalities were significantly different for tumors with and without CLNM (P < .01) and for the 4 TNM stages (P ≤ .05), with increasing values corresponding to advancement in tumor stage. Addition of DOI changed the T level of many tumors based on the new TNM (tumor-node-metastasis) classification. The correlation coefficient between DOI calculated on each MRI sequence and Path was 0.90. CONCLUSIONS: MRI-derived DOI accurately reflected the subsequent metastatic status and degree of progression of tumor stages, with a strong positive correlation to Path values, and may be considered a predictor of tumor stage and CLNM.

Imaging peculiarities of gubernaculum tracts in molars as accessional teeth on CT.

OBJECTIVES: The shapes of gubernaculum tracts (GTs) in molars as accessional teeth remain unidentified. To elucidate imaging peculiarities of GTs in molars with aging on multidetector-row computed tomography (MDCT). MATERIAL AND METHODS: This retrospective study was conducted using CT images, including maxillary and mandibular molars, with no abnormal findings from 239 patients. Shapes of alveolar bone, GTs, and dental sacs of the maxillary and mandibular molars were analyzed multi-sectionally. Correlations between 2- and 3-dimensional imaging figures of GTs in molars and chronological age or stage of molar formation were analyzed. RESULTS: Some forms of GTs in maxillary and mandibular third molars were observed. In the early stage, GTs were visualized as bone defect lines on the dentition and grooves on the mesial alveolar crest continuous with the dental sac to mesial tooth bud. GTs of the third molar formed a J-shape in maxillary teeth and Y-shape in mandibular teeth in the middle stage, as alveolar bone around the GT developed. In the mature stage, the course of the GT changed to straight and perpendicular. Some GT forms were also identified in first and second molars. Significant correlations were found between GT alterations and chronological age or stage of molar formation. Moreover, tracts continuing from the distal side of mandibular third molars were detected. CONCLUSIONS: This paper describes the peculiarities and process of progression for GTs in molars, and the existence of tracts continuing from the distal side of mandibular third molars, unlikely dentition with deciduous predecessors. These preliminary data should prove beneficial for studies focusing on GTs in molars.

Overview of Radiological Studies on Visualization of Gubernaculum Tracts of Permanent Teeth.

The eruption pathway from the dental follicle to the gingiva for permanent teeth is known as the gubernaculum tract (GT), a physiologic structure thought to play a role in tooth eruption. Cone beam computed tomography and multi-detector computed tomography have recently been used to visualize the GT, with the results indicating that this structure might be related to the normal eruption of teeth. By contrast, curved and/or constricted GTs may lead to abnormal tooth eruption. In addition, complex odontomas have been reported from within the GT or dental sac of unerupted permanent teeth. If an odontoma occurs within the GT, the tooth will not erupt normally. Moreover, the imaging characteristics of the GT from the top of the odontogenic mass to the alveolar crest are extremely useful for making a differential pathological diagnosis and for differentiating between odontogenic and non-odontogenic masses. Therefore, radiological studies on the GT have been attracting increasing attention. Given this background, the present review aims to clarify the imaging characteristics and review recent studies on the GT considering the importance of the research.