Kouji Katsura

Relationship between oral health status and development of osteoradionecrosis of the mandible: A retrospective longitudinal study

OBJECTIVE Oral health status is a risk factor for postradiation bone complications (also known as osteoradionecrosis [ORN]), and oral health care is an important element in the prevention of this condition. Some authors recommend extracting teeth with a questionable prognosis and either gross mobility or periodontal disease. However, the criteria for making such decisions remain to be elucidated. In addition, the specific details of the association between oral health status and ORN have not yet been clearly demonstrated. The purpose of this study was to clarify the relationship between oral health status and the development of ORN. STUDY DESIGN Thirty-nine head and neck cancer patients whose radiation fields included both the teeth and the mandible were followed for > or = 3 years after radiotherapy. Among these patients, 6 suffered from ORN (ORN group), and the other 33 did not experience the condition (non-ORN group). We analyzed the patient factors, radiation factors, and oral health factors related to the complication. RESULTS The onset of ORN occurred from 18 months to 51 months after radiotherapy. The radiation dose in the oral cavity and the oral health status before radiotherapy were not significant risk factors for ORN. However, the oral health status at 1 year or 2 years after radiotherapy was significantly associated with the development of ORN. The oral health conditions that increased the risk of ORN were > 5 mm periodontal pocket depth, > 40% dental plaque score, > 60% alveolar bone loss level, and a grade 3 radiographic periodontal status. CONCLUSION This is the first report to show the changes in the oral health status before and after radiotherapy regarding the development of ORN. The results support the periodontal status that almost all clinicians agree on as indications for preradiation teeth extraction (namely, periodontal pockets of > 5 mm) to prevent ORN. Good oral health status, especially after radiotherapy, is very important in the prevention of ORN, and we recommend periodical dental management and care by well trained dentists and dental hygienists to avoid the condition.

The 2G allele of promoter region of Matrix metalloproteinase-1 as an essential pre-condition for the early onset of oral squamous cell carcinoma

BackgroundMatrix metalloproteinase (MMP) is known to be involved in the initial and progressive stages of cancer development, and in the aggressive phenotypes of cancer. This study examines the association of single nucleotide polymorphisms in promoter regions of MMP-1 and MMP-3 with susceptibility to oral squamous cell carcinoma (OSCC).MethodsWe compared 170 Japanese OSCC cases and 164 healthy controls for genotypes of MMP-1 and MMP-3.ResultsThe frequency of the MMP-1 2G allele was higher and that of the 1G homozygote was lower in the OSCC cases (p = 0.034). A multivariate logistic regression analysis revealed that subjects who were 45 years old or older had a significantly increased (2.47-fold) risk of OSCC (95%CI 1.47–4.14, p = 0.0006), and those carrying the MMP-1 2G allele had a 2.30-fold risk (95%CI 1.15–4.58, p = 0.018), indicating independent involvement of these factors in OSCC. One of the key discoveries of this research is the apparent reduction of the MMP-1 1G/1G and 1G/2G genotype distributions among the early onset OSCC cases under the ages of 45 years. It should be noted that the tongue was the primary site in 86.2% of these early onset cases. This could suggest the specific carcinogenic mechanisms, i.e. specific carcinogenic stimulations and/or genetic factors in the tongue.ConclusionSince the 2G allele is a majority of the MMP-1 genotype in the general population, it seems to act as a genetic pre-condition in OSCC development. However this report suggests a crucial impact of the MMP-1 2G allele in the early onset OSCC.

The clinical significance of follow-up sonography in the detection of cervical lymph node metastases in patients with stage i or ii squamous cell carcinoma of the tongue

OBJECTIVE We sought to assess the reliability of repeated sonography in the detection of cervical lymph node metastases at the earliest stage during a follow-up period in patients with stage I or stage II carcinoma of the tongue. STUDY DESIGN Eighteen consecutive patients with stage I or II squamous cell carcinoma of the tongue were included. When possible, every patient was examined with sonography approximately every 2 weeks during the follow-up period. RESULTS With repeated sonography on 18 patients, 7 metastatic nodes of 7 patients (39%) meeting our criteria were found. With the use of computed tomography, we diagnosed 10 nodes (including the 7 nodes observed with sonography) in these 7 patients as metastatic. A histopathologic examination revealed that 12 nodes in the same 7 patients had metastatic foci. For sonography, the sensitivity per node was 58%, whereas that of computed tomography was 83%. CONCLUSIONS Follow-up sonography enabled the detection of all patients who had subsequent subclinical lymph node metastases. However, the sensitivity of sonography in the detection of smaller metastatic nodes was lower than that of computed tomography.

A case of desmoplastic ameloblastoma arising in the maxillary alveolus: the origin and time-course changes in the early stage of tumour development observed on dental radiographs

In this article we report a case of desmoplastic ameloblastoma in which chronological changes in the early development can be observed on dental radiographs. The tumour grew very slowly and did not appear to have a strong potential for local extension like typical ameloblastomas. Radiological findings of our case suggest the tumour arose from the periodontal membrane. However, it was not possible to obtain conclusive histopathological evidence.

A study on a dental device for the prevention of mucosal dose enhancement caused by backscatter radiation from dental alloy during external beam radiotherapy

The changes in dose distribution caused by backscatter radiation from a common commercial dental alloy (Au–Ag–Pd dental alloy; DA) were investigated to identify the optimal material and thicknesses of a dental device (DD) for effective prevention of mucositis. To this end, 1 cm3 of DA was irradiated with a 6-MV X-ray beam (100 MU) in a field size of 10 × 10 cm2 using a Novalis TX linear accelerator. Ethylene vinyl acetate copolymer, polyolefin elastomer, and polyethylene terephthalate (PET) were selected as DD materials. The depth dose along the central axis was determined with respect to the presence/absence of DA and DDs at thicknesses of 1–10 mm using a parallel-plate ionization chamber. The dose in the absence of DDs showed the lowest value at a distance of 5 mm from the DA surface and gradually increased with distance between the measurement point and the DA surface for distances of ≥5 mm. Except for PET, no significant difference between the DA dose curves for the presence and absence of DDs was observed. In the dose curve, PET showed a slightly higher dose for DA with DD than for DA without DD for thicknesses of ≥4 mm. The findings herein suggest that the optimal DD material for preventing local dose enhancement of the mucosa caused by DA backscatter radiation should have a relatively low atomic number and physical density and that optimal DD thickness should be chosen considering backscatter radiation and percentage depth dose.

The usefulness of follow-up sonography in the detection of subsequent cervical lymph node metastasis in patients with stage I/II tongue carcinoma

In order to assess the usefulness of repeated sonography in detecting cervical lymph node metastases at the earliest stage during a follow-up period in patients with stage I/II carcinoma 20 consecutive patients with stage I/II squamous cell carcinoma of the tongue were studied. Each patient was examined repeatedly with sonography during the follow-up period. Nine metastatic nodes in 9 of the 20 patients (45%) met our criteria, and were detected by repeated sonography. Histopathological examination revealed that 14 nodes had metastatic foci. Although the sensitivity, per node, of sonography was originally only 64%, follow-up sonography detected all of the subclinical subsequent lymph node metastases among the patients in this study. In conclusion, repeated sonography was useful in the detection of lymph node metastases during follow-up care of patients with stage I/II tongue carcinoma, provided that the follow-up examination was performed at maximum interval of one month, if possible, sonography should be performed in such cases at two-week intervals for at least one and a half year.ConclusionsRepeated sonography is useful in the detection of the lymph node metastases in patients already treated by surgery or brachytherapy for stage I/II tongue carcinoma, provided that follow-up examinations are performed at maximum intervals of one month, and, if possible, at two-week intervals for at least one and a half year.

Factors associated with mucosal dryness in multiple regions and skin: A web-based study in women

We hypothesized that feeling mucosal dryness in one body region and the skin may be associated with dryness in other regions and that there are common background factors for dryness. In an earlier web‐based survey, we reported prevalence figures of dry eyes, nose, mouth, skin, and vagina. In the present study, additional analyses were made to investigate the factors associated with dryness in each region, and simultaneous dryness in multiple regions.

Current Status of Salivary Gland Diseases: Sjögren's Syndrome and Dry Mouth

Abstract As societies age, the number of people complaining of dry mouth is increasing; an estimated 30,000,000 people suffer from dry mouth in Japan. The mouth fulfills many basic human appetites, such as eating, drinking, tasting, and talking, and a core component of these functions is saliva. In this paper we will; (1) Explain what dry mouth is; (2) Introduce Niigata University Medical and Dental Hospitals dry mouth outpatient clinic; (3) Describe a new diagnostic method using ultrasonic waves; and (4) Describe salivary protein analysis in patients suffering from Sjogrens syndrome (SS).

Multicenter phase I/II study of chemoradiotherapy with high-dose CDDP for head and neck squamous cell carcinoma in Japan

OBJECTIVE Recent data indicated that concurrent chemoradiotherapy (CCRT) using high dose cisplatin (CDDP) is the most useful treatment for advanced head and neck squamous cell carcinoma (SCC). Regarding the dose of CDDP, 100mg/m2 is most recommended in Western countries. However, in terms of a balance of efficacy and adverse events, appropriate dose of cytotoxic drugs such as CDDP may be different among the different ethnic groups. In this multicenter phase I/II study, we aimed to identify the optimal dose of CDDP in CCRT for patients with advanced head and neck SCC in the Japanese. METHODS Patients were eligible for inclusion if they had head and neck SCC that was treated with radical CCRT comprising whole-neck irradiation of the primary lesion and level II-IV lymph nodes on both sides. For the phase I study, a CDDP dose was 70mg/m2 for level 0, 80mg/m2 for level 1, and 100mg/m2 for level 2. Maximum tolerated dose (MTD) and dose-limiting toxicity (DLT) were examined by phase I trial, by which CDDP dose for phase II was determined. The primary endpoint for the phase II was CCRT completion rate, and the secondary endpoint was full-dose-CCRT completion rate, the percentage of patients receiving a total CDDP dose of ≥200mg/m2, response rate, and incidences of adverse events. RESULTS A CDDP dose of 100mg/m2 was the MTD for phase I, and the recommended dose for phase II was 80 mg/m2. Forty-seven patients were evaluated in the phase II trial. CCRT completion rate, full-dose-CCRT rate, and the percentage of patients receiving a total CDDP dose of ≥200mg/m2, were 93.6%, 78.7%, and 93.6%, respectively. One patient (2.1%) developed grade 2 renal dysfunction, and no patient developed febrile neutropenia or a grade 4 adverse event. CONCLUSION The present phase I study indicated that a CDDP dose of 80mg/m2 is the optimal dose in terms of safety. The phase II study revealed that CCRT completion rate, response rate, and rates of adverse events were not inferior for a CDDP dose of 80mg/m2 as compared with a dose of 100mg/m2, and a dose of 80mg/m2 is therefore recommended in CCRT for the Japanese. This study was registered with the University Hospital Medical Information Network Clinical Trials Registry (UMIN-CTR; identification No. UMIN000010369).

Nondestructive Microcomputed Tomography Evaluation of Mineral Density in Exfoliated Teeth with Hypophosphatasia

Most cases of hypophosphatasia (HPP) exhibit early loss of primary teeth. Results of microcomputed tomography (micro-CT) analysis of teeth with HPP have rarely been reported. The purpose of the present study was to describe the mineral density distribution and mapping of exfoliated teeth from an HPP patient using micro-CT. Four exfoliated teeth were obtained from a patient with HPP. Enamel and dentin mineral densities of exfoliated teeth were measured on micro-CT. The mean values of enamel and dentin mineral densities in mandibular primary central incisors with HPP were 1.61 and 0.98 g/cm3, respectively. The corresponding values in the mandibular primary lateral incisors were 1.60 and 0.98 g/cm3, respectively. Enamel hypoplasia was seen in the remaining teeth, both maxillary and mandibular primary canines and first and second molars. Micro-CT enables nondestructive, noninvasive evaluation and is useful for studying human hard tissues obtained from patients.