The purpose of this study was to compare findings on the relationship between impacted molar roots and the mandibular canal in panoramic and three-dimensional cone-beam CT (CBCT) images to identify those that indicated risk of postoperative paresthesia. The relationship between impacted molars and the mandibular canal was first classified using panoramic images. Only patients in whom the molar roots were either in contact with or superimposed on the canal were evaluated using CBCT. Of 466 patients examined using both panoramic and CBCT images, 280 underwent surgical extraction of an impacted molar, and 15 of these (5%) reported postoperative paresthesia. The spatial relationship between the impacted third molar root and the mandibular canal was determined by examining para-sagittal sections (lingual, buccal, inter-radicular, inferior, and combinations) obtained from the canal to the molar root and establishing the proximity of the canal to the molar root (in contact with or without loss of the cortical border and separate). The results revealed that darkening of the roots with interruption of the mandibular canal on panoramic radiographs and the inter-radicular position of the canal in CBCT images were characteristic findings indicative of risk of postoperative paresthesia. These results suggest that careful surgical intervention is required in patients with the above characteristics.
The purpose of this study was to evaluate grinding efficiency in abutment teeth comprising both dentin and core composite resin in the axial plane. Grinding was performed over 5 runs at two loads (0.5 or 0.25 N) and two feed rates (1 or 2 mm/sec). The grinding surface was observed with a 3-D laser microscope. Tomographic images of the grinding surfaces captured perpendicular to the feed direction were also analyzed. Using a non-ground surface as a reference, areas comprising only dentin, both dentin and core composite resin, or only core composite resin were analyzed to determine the angle of the grinding surface. Composite resins were subjected to the Vickers hardness test and scanning electron microscopy. Data were statistically analyzed using a one-way analysis of variance and multiple comparison tests. Multiple regression analysis was performed for load, feed rate, and Vickers hardness of the build-up material depending on number of runs. When grinding was performed at a constant load and feed rate, a greater grinding angle was observed in areas comprising both dentin and composite resin or only composite resin than in areas consisting of dentin alone. A correlation was found between machinability and load or feed rate in areas comprising both dentin and composite resin or composite resin alone, with a particularly high correlation being observed between machinability and load. These results suggest that great caution should be exercised in a clinical setting when the boundary between the dentin and composite resin is to be ground, as the angle of the grinding surface changes when the rotating diamond point begins grinding the composite resin.
Oral health instruction for adults should take into account the potential effect of tooth loss, as this has been suggested to predict further tooth loss. Therefore, the purpose of this study was to determine whether further tooth loss could be predicted from the number of present teeth (PT). We employed the same method as in our previous study, this time using two national surveys of dental disease, which were deemed to represent a generational cohort. Percentiles were estimated using the cumulative frequency distribution of PT from the two surveys. The first was a survey of 704 participants aged 50-59 years conducted in 2005, and the second was a survey of 747 participants aged 56-65 years conducted in 2011. The 1st to 100th percentiles of the number of PT were calculated for both age groups. Using these percentiles and a generational cohort analysis based on the two surveys, the number of teeth lost per year could be calculated. The distribution of number of teeth lost generated a convex curve. Peak tooth loss occurred at around 12-14 PT, with 0.54 teeth being lost per year. The percentage of teeth lost (per number of PT) increased as number of PT decreased. The results confirmed that tooth loss promotes further tooth loss. These data should be made available for use in adult oral health education.
Atmospheric plasma or ultraviolet (UV) treatment alters the surface characteristics of tetragonal zirconia polycrystal (TZP), increasing its hydrophilicity by reducing the contact angle against water to zero. This suggests that such treatment would increase the wettability of bonding resin. The purpose of this study was to determine how increasing the hydrophilicity of TZP through plasma irradiation, UV treatment, or application of ceramic primer affected initial bonding with resin composites. Here, the effect of each pre-treatment on the hydrophilicity of TZP surfaces was determined by evaluating change in shear bond strength. Plasma irradiation, UV, or ceramic primer pre-treatment showed no significant effect on bonding strength between TZP surfaces and resin composites. In addition, alumina blasting yielded no significant increase in bond strength. Plasma irradiation, UV treatment, or ceramic primer pre-treatment did not lead to significant increase in bond strength between TZP and resin composites.
Carcinoma of unknown primary (CUP) is where the primary site remains unidentified even though metastases are present, and accounts for 3-5% of all human malignancies. Here, we report a multidisciplinary approach to the treatment of a squamous cell CUP occurring in the left cervical region. Following radical surgery for carcinoma of the colon, swelling occurred in the left cervical region in a 59-year-old man. The results of an incisional biopsy indicated a diagnosis of squamous cell carcinoma (SCC), and he was referred to our department for examination. The primary carcinoma was not identifiable despite an extensive diagnostic workup including a physical examination, fiberoptic endoscopy, computed tomography, magnetic resonance imaging, and fluorodeoxyglucose F18 positron emission tomography, resulting in a diagnosis of an SCC of unknown in the cervical region. The patient was initially treated with three cycles of docetaxel 75 mg/m2/day, cisplatin 100 mg/m2/day, and 5-fluorouracil 1,000 mg/m2/day as induction chemotherapy. This was followed by concurrent chemoradiotherapy (cisplatin 30 mg/m2/day, 70 Gy) and neck dissection. Subsequent pathological examination revealed no vestiges of the tumor. The patient has remained free from recurrence and metastasis for 6 years.
Cystadenoma, a common benign tumor derived from glandular tissue, generally occurs in the appendix, ovaries, kidney, or pancreas. While rare in the oral and maxillofacial region, they do sometimes occur in the parotid or minor salivary glands. We report a case of cystadenoma arising in the upper lip region. The patient was a 37-year-old woman referred to our hospital with a painless mass on the left upper lip initially found during treatment at a local dental clinic. The medical history was non-contributory. The 7×5-mm mass was well-defined, elastic, and flexible. The surface of the mucosa appeared healthy. The mass was clinically diagnosed as a benign tumor of the left upper lip. Because the tumor was painless and slow-growing, and magnetic resonance imaging suggested that it was benign, resection was performed under local anesthesia without biopsy. Histopathologically, cystadenoma was diagnosed. No signs of recurrence or metastasis have been seen as of 24 months postoperatively and the progress of the patient has been satisfactory.
The need for smoking cessation care is widely recognized. It is, however, difficult to achieve continued smoking abstinence, even when cessation has initially been achieved. The aim of this study was to determine the effectiveness of a collaborative smoking cessation program involving both medical and dental professionals on smoking abstinence. A total of 10 patients visiting our Smoking Cessation Outpatient Clinic were followed up and monitored for smoking abstinence. All received smoking cessation care consisting mainly of counseling by dental and medical professionals and pharmacotherapy. They also concurrently received an oral examination, instruction on oral hygiene, and professional tooth cleaning. The 4-week smoking abstinence rate was 90.0% on completion of the program. One patient failed to complete the program. At one month after the program, 8 out of 9 patients remained abstinent (4-month abstinence; 88.9%). At 3 months after the program, 7 patients remained abstinent (6-month abstinence; 77.8%). Follow-up was impossible in one patient. Within the limitations of the present study, it is suggested that such collaborative intervention including subsequent dental care has the potential to promote short-term adherence to smoking abstinence.
The aim of this study was to investigate sex- and age-based differences in single tooth loss in adults. The data were obtained from the results of a periodontal disease examination carried out under a health promotion law in a city in Japan in 2005. Baseline data from a total of 3,872 participants aged 40 or 60 years comprising 1,302 men and 2,570 women were available. Only participants with 27 present teeth were eligible for inclusion in the analysis, giving a total of 218 men and 428 women. Third molars were excluded from the study. The bilateral total of each type of tooth was obtained. The mandibular first molar was missing in 26.7% of the men and 36.2% of the women among 40-year-olds and 35.3% of the men and 29.8% of the women among 60-year-olds. The mandibular second molar was missing in 14.7% of the men and 12.5% of the women among 40-year-olds, and 17.6% of the men and 18.4% of the women among 60-year-olds. Significant differences were observed between men and women in the mandibular second premolars and first molars among 40-year-olds. These results suggest that we need to pay more attention to individual teeth which are at particularly high risk for tooth loss, namely the mandibular first and second molars, and especially the mandibular first molars in middle-aged women.