Junya Kusumoto

Brain Abscess Potentially Resulting from Odontogenic Focus: Report of Three Cases and a Literature Review

IntroductionOdontogenic foci can rarely cause intracranial infection. Hematogenous spread is considered to be the most important pathophysiological mechanism of intracranial infection of odontogenic origin. To investigate the oral origin of intracranial infections, oral surgeons should understand the underlying mechanisms by which oral bacteria spread to the central nervous system. However, there have been very few reports of intracranial infection resulting from odontogenic infection. Case reportsThe authors report the cases of a 64-year-old man, a 68-year-old man, and a 64-year-old woman whose brain abscesses perhaps have arisen from odontogenic foci, because other sources of intracranial infection such as endocarditis and maxillary sinusitis were not found. Bacteriological examination of brain abscess specimens identified Staphylococcus aureus in case 1, Streptococcus constellatus, Fusobacterium nucleatum, and Parvimonas micra in case 2, and Lactobacillus catenaformis, Porphyromonas gingivalis, and F. nucleatum in case 3. All suspected causal teeth had no obvious signs of acute inflammation in all three cases. ConclusionsOral surgeons should understand these characteristics of odontogenic brain abscess, in which the potentially causal odontogenic foci often lack acute symptoms. If other origins of infection are not found, it would be better to eliminate the potentially causal odontogenic foci for improvement of oral hygiene, however, the decision making criteria to eliminate suspected causal teeth is needed to be elucidated.

Myelosuppression grading of chemotherapies for hematologic malignancies to facilitate communication between medical and dental staff: lessons from two cases experienced odontogenic septicemia

BackgroundOdontogenic diseases can be a risk factor for life-threatening infection in patients with hematologic malignancies during chemotherapy that induces myelosuppression of variable severity. Previous studies noted the necessity of the elimination of all odontogenic foci before hematopoietic stem cell transplantation. To enable planning for the adequate dental intervention, the oral medicine team must understand the general status of patient and the intensity of the chemotherapy, which is sometimes difficult to be fully appreciated by dental staff. Therefore, a simplified grading would facilitate the sharing of information between hematologists, dentists and oral hygienists. This study aimed to introduce our myelosuppression grading of chemotherapies for hematologic malignancies and analyze the timing of occurrence of severe odontogenic infection.Methods37 patients having received various chemotherapies for hematologic malignancies were enrolled. The chemotherapy regimens were classified into four grades based on the persistency of myelosuppression induced by chemotherapy. Mild myelosuppressive chemotherapies were classified as grade A, moderate ones as grade B, severe ones as grade C, and chemotherapies that caused severe myelosuppression and persistent immunodeficiency (known as conditioning regimens for transplant) as grade D. The timing of occurrence of severe odontogenic infection was retrospectively investigated.ResultsTwo patients (5.4%) had severe odontogenic infections after grade B or C chemotherapy. One occurred after extraction of non-salvageable teeth; the other resulted from advanced periodontitis in a tooth that could not be extracted because of thrombocytopenia. Both were de novo hematologic malignancy patients. During grade D chemotherapy, no patients had severe odontogenic infections.ConclusionsThe simplified grading introduced in this study is considered a useful tool for understanding the myelosuppressive state caused by chemotherapy and facilitating communication between medical and dental staff. During the period around the primary chemotherapy, especially for de novo hematologic malignancy patients who often received grade B to C myelosuppression chemotherapy, caution should be exercised for severe odontogenic infection by the oral medicine team, irrespective of whether invasive treatment is to be performed.

Intensity and duration of neutropenia relates to the development of oral mucositis but not odontogenic infection during chemotherapy for hematological malignancy

Background D-index which combines the intensity and duration of neutropenia is reported as a tool for evaluating the dynamics of neutropenia. This study aimed to analyze the relationship between D-index and oral complications (i.e., oral mucositis [OM] and odontogenic infection [OI]) during chemotherapies for hematological malignancies. Methods A total of 421 chemotherapeutic courses in 104 patients were analyzed. Chemotherapeutic courses in patients who finished all of the prophylactic dental treatments were defined as “treatment Finish”. Chemotherapeutic courses in patients who did not finish prophylactic dental treatments were defined as “treatment not-Finish”. OM was evaluated according to the Common Terminology Criteria for Adverse Events, version 4.0. D-index was compared between chemotherapeutic courses with versus without oral complications. Results D-index was significantly higher in chemotherapeutic courses with grade 1 or 2 OM (p < 0.001) than courses without OM. In contrast, higher D-index did not relate to the development of OI (p = 0.18). The occurrence of OI (p < 0.001) but not OM (p = 0.56) during chemotherapy was significantly higher in chemotherapeutic courses without the completion of dental intervention. Conclusions Higher D-index relates to the development of OM. In contrast, OI occurs due to untreated odontogenic foci, and its occurrence does not relate to higher D-index.

Perioperative intervention by oral medicine team in cardiovascular surgery patients

In brief, perioperative oral intervention consists of elimination of odontogenic foci and maintenance of oral hygiene in patients undergoing surgery. The importance of oral intervention before, during, and after medical treatments is well-known, especially in cancer patients, because odontogenic foci such as untreated deep dental caries or periodontitis can cause systemic infection in patients with myelosuppression resulting from chemotherapy. Although perioperative oral intervention is currently recommended for patients with cardiovascular disease, its efficacy in this population has not been established. This article consists of three sections: first, we review the current knowledge about the association between dental disease and cardiovascular disease to show the importance of oral hygiene maintenance and the risks of invasive dental procedures in patients with cardiovascular disease; second, we introduce pertinent, but limited evidence concerning the effect of oral care in preventing postoperative pneumonia; and finally, we present the optimal strategy for perioperative oral intervention in cardiovascular surgery patients.

Differences between osteoradionecrosis and medication-related osteonecrosis of the jaw

PurposeThe appearance of osteoradionecrosis (ORN) and medication-related osteonecrosis of the jaw (MRONJ) is similar, but clinically important differences between ORN and MRONJ exist. The aim of this study was to compare the clinical data between ORN and MRONJ and to reveal the critical differences between these diseases.MethodsWe retrospectively reviewed the epidemiological data, clinical findings, and treatment in 27 ORN and 61 MRONJ patients. Radiographic signs before the initiation of treatment were also assessed.ResultsThe median age (P = 0.0474) and the ratio of female to male patients (P < 0.0001) were significantly higher in MRONJ patients. There were significantly more MRONJ patients who reported a history of pain when compared with ORN patients (P = 0.0263). As an aetiological factor, tooth extraction was significantly more relevant to MRONJ than ORN (P = 0.0352). When assessing the radiographic signs on computed tomographic images, periosteal reaction was found only in MRONJ patients (P = 0.0158). Minimal debridement was performed significantly more frequently for MRONJ (P = 0.0093), and by contrast, surgical resection was performed more frequently for ORN (P = 0.0002).ConclusionsUnderstanding the clinical and underlying pathological differences between ORN and MRONJ probably contributes to the selection of appropriate treatment for each patient.

Association between pain severity and clinico-histopathological findings in the mandibular canal and inferior alveolar nerve of patients with advanced mandibular osteoradionecrosis

OBJECTIVE Pain is one of the most problematic symptoms in patients with osteoradionecrosis of the jaws. This study investigated the associations between pain severity and morphologic alterations of the mandibular canal and inferior alveolar nerve, in respective computerized tomography images and resected specimens of mandibular osteoradionecrosis. STUDY DESIGN We assessed 14 lesions in 13 patients who underwent segmental mandibulectomy for surgical debridement and simultaneous reconstruction with free fibula flap (1 patient exhibited bilateral lesions). The extent of the mandibular canal bone defect on preoperative coronal computerized tomography images and the number of inferior alveolar nerve fascicles in resected specimens were evaluated. Comparisons were made between the slight pain and extreme pain groups. In most of the patients in the extreme pain group, either mandibular canal bone defects were absent or entire circumferential defects were present; inferior alveolar nerve fascicles were either distinguishable or completely absent in the resected specimens. RESULTS Although there was no statistically significant association between extreme pain and computerized tomography or histopathologic findings, the histopathologically indistinguishable inferior alveolar nerve fascicles was significantly associated with slight pain. CONCLUSIONS The degree of degeneration of mandibular canal and inferior alveolar nerve may be associated with pain severity in patients with mandibular osteoradionecrosis.

Long-Term Effects on Volume Change in Musculocutaneous Flaps after Head and Neck Reconstruction

Objective Musculocutaneous flap reconstruction surgery is one of the standard procedures following head and neck cancer resection. However, no previous studies have classified flaps in terms of muscle and fat or examined them after long‐term follow‐up. The purpose of this study was to estimate the fat and muscle volume changes in musculocutaneous flaps during long‐term follow‐up. Methods We conducted a retrospective analysis of 35 patients after musculocutaneous flap reconstruction. The total, fat, and muscle volumes of the musculocutaneous flaps were measured using 3‐dimensional images. Changes in flap volumes over time (1 month, 1 year [POY1], and 5 years [POY5] postoperatively) were assessed. Flap persistence was calculated using flap volumes at 1 month after reconstruction for reference. Results Flap persistence at POY5 was 42.0% in total, 64.1% in fat, and 25.4% in muscle. Muscle persistence was significantly decreased (p < 0.0001). In a multiple regression analysis, decreased body mass index (BMI) of ≥ 5% influenced fat persistence less than muscle persistence at POY1; however, there was no significant difference at POY5. Postoperative radiation therapy was associated with a significant decrease in total flap persistence at POY1 (p = 0.046) and POY5 (p = 0.0097). Muscle persistence significantly decreased at POY5 (p = 0.0108). Age significantly influenced muscle volume at POY1 (p = 0.0072). Conclusion Reconstruction flaps are well‐preserved with high fat‐to‐muscle ratios. Recommendations for weight maintenance are necessary for patients less than 2 years after surgery due to the influence of BMI on fat persistence. Radiation therapy is necessary for some patients based on their disease state. Intensity‐modulated radiation therapy can be offered to reduce scattering irradiation to normal tissues.

Upregulated Expression of Transient Receptor Potential Cation Channel Subfamily V Receptors in Mucosae of Patients with Oral Squamous Cell Carcinoma and Patients with a History of Alcohol Consumption or Smoking

Objectives Transient receptor potential cation channel (subfamily V, members 1–4) (TRPV1–4) are expressed in skin and neurons and activated by external stimuli in normal mucosae of all oral cavity sites. The oral cavity is exposed to various stimuli, including temperature, mechanical stimuli, chemical substances, and changes in pH, and, notably, the risk factors for oncogenic transformation in oral squamous epithelium are the same as the external stimuli received by TRPV1–4 receptors. Hence, we examined the relationship between oral squamous cell carcinoma (SCC) and TRPV1–4 expression. Materials and Methods Oral SCC patients (n = 37) who underwent surgical resection were included in this study. We investigated the expression of TRPV1–4 by immunohistochemical staining and quantification of TRPV1–4 mRNA in human oral mucosa. In addition, we compared the TRPV1–4 levels in mucosa from patients with SCC to those in normal oral mucosa. Results The receptors were expressed in oral mucosa at all sites (tongue, buccal mucosa, gingiva, and oral floor) and the expression was stronger in epithelia from patients with SCC than in normal epithelia. Furthermore, alcohol consumption and tobacco use were strongly associated with the occurrence of oral cancer and were found to have a remarkable influence on TRPV1–4 receptor expression in normal oral mucosa. In particular, patients with a history of alcohol consumption demonstrated significantly higher expression levels. Conclusion Various external stimuli may influence the behavior of cancer cells. Overexpression of TRPV1-4 is likely to be a factor in enhanced sensitivity to external stimuli. These findings could contribute to the establishment of novel strategies for cancer therapy or prevention.

Potential role of post‑treatment follow‑up FDG‑PET CT to detect mandibular osteoradionecrosis: A case report

It was hypothesized that fluorodeoxyglucose (FDG) uptake on post-treatment follow-up positron emission tomography with computed tomography (PET CT; using PET CT to monitor and rule out recurrence and metastasis of head and neck carcinoma) would be useful for detecting and understanding the disease state of osteoradionecrosis (ORN) of the jaw. The present study included 14 patients who developed mandibular ORN following radiation therapy (RT) for head and neck cancer and underwent follow-up PET CT several times following RT. Areas exhibiting FDG uptake were retrospectively assessed on post-treatment follow-up PET CT images and were classified into three types: Spot type: Only spot accumulation of FDG; localized type: Accumulation of FDG restricted to within the bone resorption area; extensive type: Accumulation of FDG extending into surrounding soft tissue. PET classification at the time of clinical diagnosis of mandibular ORN in the 14 patients demonstrated the extensive type in 43%, localized type in 36% and spot type in 21%. An increased area of FDG uptake around the ORN was revealed retrospectively on post-treatment follow-up FDG PET-CT images in 50% of patients. Alterations in PET classification included spot type to localized type in 36% and localized type to extensive type in 14%. A significantly increased number of patients with extensive-type ORN (P=0.026) required surgery. Post-treatment follow-up FDG-PET CT may be useful for early detection and better understanding of ORN.

Axial four-dimensional computed tomographic images to analyze crosswise differences in protrusive condylar movement in patients who underwent mandibulectomy and free flap reconstruction

OBJECTIVE Few studies evaluate condylar movement following mandibular reconstruction. The main objective of this study was to show that axial four-dimensional computed tomography (4DCT) could visualize bilateral protrusive condylar movement directly. We used axial 4DCT images to assess condylar protrusion in patients who underwent mandibular reconstruction. METHODS We enrolled seven healthy volunteers (median age 30 years, range 27-38 years) and seven patients (median age 65 years, range 52-80 years), who underwent mandibulectomy (segmental in five, hemi in one, marginal in one) and free flap reconstruction (using the fibula in six and the radial forearm in one). Six study subjects were instructed to masticate a cookie during the 4DCT scan (the seventh made chewing motions). The distance between the most anterior and posterior positions of the bilateral condyles on 4DCT (axial view) images was then measured and compared between controls and patients using the Mann-Whitney U-test. RESULTS The crosswise difference in the distances of condylar protrusion was significantly greater in patients than in the controls. CONCLUSION Axial 4DCT images can visualize a bilateral condylar protrusive path. Axial 4DCT images for patients who have undergone mandibulectomy and reconstruction may be useful for evaluation of functional movement of condyles.