Differences Between Medication-Related Osteonecrosis of the Jaw Caused by Bisphosphonates and Denosumab: Histological, Molecular Biological, and Clinical Studies.

Purpose Medication-related osteonecrosis of the jaw (MRONJ) is a serious side effect of antiresorptive agents such as bisphosphonates (BPs) and denosumab (DMB). We investigated whether a difference exists between BP- and DMB-related osteonecrosis of the jaw (ONJ). Patients and methods Histological images of 30 patients with BP-related ONJ and 13 patients with DMB-related ONJ were observed using hematoxylin-eosin and cathepsin K staining. Moreover, bone metabolism markers in the blood and bone mineral density were measured in 18 patients with BP-related ONJ and five patients with DMB-related ONJ. Furthermore, we conducted a quantitative analysis of local bone metabolism-related genes using surgical specimens through real-time reverse transcription polymerase chain reaction. Additionally, a retrospective study of 298 patients with MRONJ examined the differences in the characteristics of BP- and DMB-related ONJ and the factors associated with treatment outcomes. Results Histological examination revealed that patients treated with DMB had more severe osteoclast suppression than those treated with BP. No significant difference was observed in blood-bone metabolism markers between the two drugs; however, the suppression of local bone metabolism-related genes was stronger in patients treated with DMB. Clinical studies indicate that DMB-related ONJ is more frequently observed without osteolysis. Conclusion BP-associated ONJ and DMB-associated ONJ were shown to differ slightly. Clinical studies indicate that osteolysis is often unclear in DMB-related ONJ, and methods of bone resection during surgery need to be established.

Bone resection methods in medication-related osteonecrosis of the jaw in the mandible: An investigation of 206 patients undergoing surgical treatment.

Background /purpose: The standard treatment for medication-related osteonecrosis of the jaw (MRONJ) is surgery. However, reports on the appropriate extent of bone resection are few. We aimed to examine the relationship between the extent of bone resection and postoperative outcomes in patients with mandibular MRONJ. Materials and methods: The clinical and imaging findings and treatment outcomes of 206 patients (258 surgeries) with mandibular MRONJ undergoing surgery were reviewed. Imaging findings were evaluated using computed tomography (CT) to sequestrum, osteolysis, periosteal reaction, and mixed-type osteosclerosis, and determine the extent of resection. In some cases, samples were taken from within the bone, and real-time polymerase chain reaction was used to confirm the presence of bacteria and fungi. Results: The three-year cumulative cure rate was 81.7%. Patients with malignant tumors showing no osteolysis and undergoing sequestrum removal or marginal mandibulectomy had significantly worse prognosis than those with osteoporosis showing osteolysis and undergoing segmental mandibulectomy. Furthermore, patients with residual osteolysis, periosteal reactions, and mixed-type osteosclerosis on CT were more likely to develop recurrence. Eleven patients showed no osteolysis on CT images. Patients with cancer administered with high-dose denosumab had significantly poorer prognosis. Bacteria and fungi were also detected in samples obtained from gap-type periosteal reaction and mixed-type osteosclerosis. Conclusion: Surgery for MRONJ requires resection of the infected bone. Aside from the osteolysis area, the gap-/irregular-type periosteal reaction and mixed-type osteosclerosis must also be included in the resection area. Methods for determining the extent of bone resection in MRONJ without osteolysis are a future challenge.

Medication-related osteonecrosis of the upper jaw involving the zygomatic bone: A case report.

INTRODUCTION AND IMPORTANCE: Osteonecrosis of the jaw resulting from treatment with antiresorptive agents, such as bisphosphonates and denosumab, is widely recognized as medication-related osteonecrosis of the jaw (MRONJ). However, to the best of our knowledge, there are no reports of medication-related osteonecrosis of the upper jaw extending to the zygomatic bone. CASE PRESENTATION: An 81-year-old woman treated with denosumab for multiple lung cancer bone metastases presented to the authors' hospital with a swelling in the upper jaw. Computed tomography showed osteolysis, periosteal reaction of the maxillary bone, maxillary sinusitis, and osteosclerosis of the zygomatic bone. The patient underwent conservative treatment; however, osteosclerosis of the zygomatic bone progressed to osteolysis. CLINICAL DISCUSSION: If the maxillary MRONJ extends to the surrounding bony structures, such as the orbit and skull base, serious complications may occur. CONCLUSION: It is important to detect early signs of maxillary MRONJ, before it involves the surrounding bones.

Ineffectiveness of Antiresorptive Agent Drug Holidays in Osteoporosis Patients for Treatment of Medication-Related Osteonecrosis of the Jaw: Consideration from Immunohistological Observation of Osteoclast Suppression and Treatment Outcomes.

In patients with osteoporosis receiving antiresorptive agents (ARs), it has been widely practiced to withdraw ARs for several months before tooth extraction and during treatment if medication-related osteonecrosis of the jaw (MRONJ) develops. This study examined the effects of drug holidays on recovery from osteoclast suppression and the treatment outcomes. The relationship between the period of the drug holidays and treatment outcomes was examined retrospectively in 166 osteoporosis patients with MRONJ who received ARs. Histological examinations using hematoxylin and eosin staining and cathepsin K stains were performed to observe the recovery from osteoclast suppression in 43 patients in whom living bone was observed in the resection margins of the surgical specimens. Three-month AR drug holidays were not significantly correlated with the treatment outcomes of the 139 patients who underwent surgical treatment and the 27 who underwent conservative treatment. Of the 43 patients who underwent histological investigations, 16 had drug holidays from 7 to 678 days. Osteoclast suppression was observed in almost all patients, except in one without a drug holiday and one with a 261-day drug holiday. These findings suggest that AR drug holidays for approximately 3 months neither recover osteoclast suppression nor affect treatment outcomes.

Relationship between drug holiday of the antiresorptive agents and surgical outcome of medication-related osteonecrosis of the jaw in osteoporosis patients.

A drug holiday of 3 months does not promote separation of sequestra and is not correlated with treatment outcomes after surgical therapy in osteoporosis patients who receive antiresorptive agents and who have medication-related osteonecrosis of the jaw. Medication-related osteonecrosis of the jaw (MRONJ) is a serious adverse effect of antiresorptive agents alone or in combination with immune modulators or antiangiogenic medications, in the absence of radiation exposure to the head and neck region. The effectiveness of surgical treatment for MRONJ has been reported, but the timing of the operation remains controversial. The purpose of this study was to clarify whether preoperative drug holidays of antiresorptive agents promote sequestrum separation and improve treatment outcomes in patients who receive low doses of antiresorptive agents. This retrospective study included 173 patients who received low-dose antiresorptive agents and underwent surgical therapy. The effects of a drug holiday on the separation of sequestra and treatment outcomes were analyzed using logistic and Cox regression analyses. Multivariate analysis revealed that administration of an antiresorptive agent for more than 4 years, a high number of lymphocytes, and an extensive osteolytic area were significantly correlated with separation of sequestra, but drug holiday did not promote sequestrum separation. Furthermore, a drug holiday of 90, 120 or 180 days did not show any improvement in treatment outcomes. The drug holiday of the antiresorptive agents for the treatment of MRONJ is unnecessary, and surgical therapy should be performed early.

Efficacy of 3% hydrogen peroxide solution in cleaning tongue coating before and after surgery: a randomized phase II study.

BACKGROUND: Increased bacterial presence in the tongue coating and thereby, the saliva, may be a risk factor for postoperative complications such as surgical site infection or postoperative pneumonia after cancer surgery. However, no method for cleaning tongue coating has been established experimentally. The purpose of this study was to verify the effect of brushing with 3% hydrogen peroxide on suppression of the number of bacteria in tongue coating. METHODS: Sixteen patients with gastric cancer or colorectal cancer undergoing surgery were randomly allocated to control and intervention groups. In the control group, the tongue was brushed for 30 s with a water-moistened toothbrush, while in the intervention group, the tongue was brushed for 30 s with a toothbrush moistened with 3% hydrogen peroxide. Bacterial counts on tongue coating were measured before and 30 s after cleaning the tongue coating using the Rapid Oral Bacteria Quantification System. RESULTS: In the control group, the number of bacteria on the tongue did not decrease significantly after tongue cleaning on the day before surgery, but did on the day after surgery. In contrast, in the intervention group, the number of bacteria on the tongue decreased significantly after tongue cleaning both on the day before and the day after surgery. Furthermore, when comparing the control and intervention groups, the intervention group had a greater reduction effect. CONCLUSIONS: Tongue brushing with 3% hydrogen peroxide is a useful method to reduce the number of bacteria on the tongue in patients with gastrointestinal cancer undergoing surgery. Trial registration jRCTs071200020 (July 3, 2020).

Factors Exacerbating Clinical Symptoms and CT Findings in Patients with Medication-Related Osteonecrosis of the Jaw Receiving Conservative Therapy: A Multicenter Retrospective Study of 53 Cases.

Recent reports have shown that better treatment outcomes are obtained with surgical therapy in patients with medication-related osteonecrosis of the jaw (MRONJ) than with conservative therapy. However, conservative treatment is selected due to factors such as old age and poor general condition. Conservative therapy aims to relieve symptoms and prevent lesion exacerbation; however, the lesion may expand rapidly in some cases. This study investigated the clinical and imaging findings of 53 MRONJ patients undergoing conservative therapy, and the changes in the clinical findings and the lesion enlargement on CT imaging were examined. Improved clinical findings and no worsening of the imaging findings were considered overall comprehensive treatment successes. Among the 53 patients, the clinical symptoms disappeared or improved in 15 patients, whereas they worsened in 6. In contrast, osteolytic lesion enlargement occurred in 17 patients. The comprehensive treatment outcome of conservative therapy was successful in 12 patients and unsuccessful in 41 patients. The periosteal reaction was significantly correlated with poor comprehensive treatment outcomes (p = 0.038). MRONJ lesions may advance, even if they appear to improve clinically while undergoing conservative treatments. Patients, especially those with periosteal reactions, must be closely followed up with CT examinations, regardless of the clinical findings.

Retrospective Analysis of Treatment Outcomes of Maxillary Sinusitis Associated with Medication-Related Osteonecrosis of the Jaw.

Although maxillary sinusitis often occurs in patients with medication-related osteonecrosis of the jaw (MRONJ) of the upper jaw, there have been few reports on the treatment and outcomes for maxillary sinusitis associated with maxillary MRONJ. This study aimed to retrospectively investigate the treatment outcomes of maxillary sinusitis in patients with MRONJ of the upper jaw. There were 34 patients diagnosed with maxillary MRONJ and sinusitis by preoperative computed tomography who underwent surgery in our institution between January 2011 and December 2019. Age, sex, primary disease, stage of MRONJ, class and administration period of an antiresorptive agent, corticosteroid administration, preoperative leukocyte count and serum albumin level, periosteal reaction, sinusitis grade, maxillary sinus surgical procedure, and treatment outcomes of MRONJ and sinusitis were examined. There were 7 male and 27 female patients (average age, 74.7 years). Complete healing of MRONJ was obtained in 29 of 34 patients (85.3%). Maxillary sinusitis resolved or improved in 21 patients (61.8%) but did not change or worsen in 13 patients (38.2%). We found that complete resection of necrotic bone with intraoperative irrigation of the maxillary sinus may provide good treatment outcomes for maxillary sinusitis associated with MRONJ, although our findings were not statistically significant owing to the small number of patients.

Risk factors for developing medication-related osteonecrosis of the jaw when preserving the tooth that can be a source of infection in cancer patients receiving high-dose antiresorptive agents: a retrospective study.

PURPOSE: To retrospectively investigate whether apical lesion, alveolar bone loss, probing pocket depth, or local infectious symptoms were associated with the onset of medication-related osteonecrosis of the jaw (MRONJ) in patients treated with high-dose antiresorptive agents who did not undergo tooth extraction. METHODS: The study included 92 patients receiving high-dose antiresorptive agent therapy who had teeth with apical lesion ≧ 3 mm, alveolar bone loss ≧ 1/2, probing pocket depth ≧ 4 mm, or local infection symptoms such as swelling, pain, and pus discharge, but did not undergo tooth extraction. Univariate and multivariate Cox regression analyses were performed to determine the relationship between each variable and MRONJ onset. RESULTS: MRONJ developed in 15 of 92 patients (35 of 404 teeth) from 74 to 1883 days (median, 383 days) after the first visit. Multiple Cox regression analysis revealed that a lower number of teeth, diabetes, increased leukocyte count, administration of antiresorptive agents for 180 days or more, local infection symptoms, apical lesion ≧ 3 mm, and probing pocket depth ≧ 4 mm were significantly correlated with the development of MRONJ. CONCLUSION: It is recommended that teeth with apical lesion ≧ 3 mm, probing pocket depth ≧ 4 mm, or local infection symptoms are extracted before or as early as possible after beginning of medication in cancer patients receiving high-dose antiresorptive agent therapy to prevent the development of MRONJ.

Perioperative oral care can prevent surgical site infection after colorectal cancer surgery: A multicenter, retrospective study of 1,926 cases analyzed by propensity score matching.

BACKGROUND: Surgical site infection is a common postoperative complication of colorectal cancer surgery, and surgical site infection increases medical costs, prolongs hospitalization, and worsens long-term prognosis. Perioperative oral care has been reported to be effective in preventing postoperative pneumonia, although there are only a few reports on its effectiveness in preventing surgical site infection. This study aimed to determine the role of perioperative oral care in surgical site infection prevention after colorectal cancer surgery. METHODS: In this study, 1,926 patients with colorectal cancer from 8 institutions were enrolled; 808 patients (oral care group) received perioperative oral care at the hospital's dental clinic, and 1,118 (control group) did not receive perioperative oral care. The data were matched by propensity score to reduce bias. Ultimately, a total of 1,480 patients were included in the analysis. RESULTS: The incidence of surgical site infection was significantly lower in the oral care group than in the control group (8.4% vs 15.7%, P < .001). Multivariate logistic regression analysis revealed 4 independent risk factors for surgical site infection: low albumin level, rectal cancer, blood loss, and lack of perioperative oral care. Lack of perioperative oral care had an odds ratio of 2.100 (95% confidence interval 1.510-2.930, P < .001). CONCLUSION: These results suggest that perioperative oral care can reduce the incidence of surgical site infection after colorectal cancer resection. Perioperative oral care may have an important role in the future perioperative management of colorectal cancer as a safe and effective method of surgical site infection prevention, although further validation in prospective studies is needed.

Relationship between Drug Holidays of Antiresorptive Agents and Surgical Outcomes in Cancer Patients with Medication-Related Osteonecrosis of the Jaw.

It is controversial as to whether the withdrawal of antiresorptive (AR) agents is necessary while treating medication-related osteonecrosis of the jaw (MRONJ). In this study, we investigated whether a drug holiday promoted sequestrum separation and improved the surgical outcomes of MRONJ patients with malignant tumors, who were undergoing high-dose AR therapy. In total, we included 103 MRONJ patients with malignant tumors as their primary disease who underwent surgery at Nagasaki University Hospital or Kansai Medical University Hospital from January 2009 to December 2020. We recorded the patients' age, sex, primary disease, MRONJ stage, type and administration period of the AR agent, presence of diabetes, corticosteroid use, drug holiday period, white blood cell count, serum albumin, serum creatinine, outcomes, and computed tomography findings. The relationships between a drug holiday and sequestrum separation, and between a drug holiday and outcome, were analyzed. Drug holidays of 60, 90, and 120 days were not significant factors of sequestrum separation and did not influence patients' surgical outcomes as per the univariate and multivariate analyses. MRONJ patients with cancer as their primary disease should be operated upon immediately and without drug holidays if their general condition permits surgery.

A preliminary clinical study of segmental mandibulectomy on medication-related osteonecrosis of the jaw.

BACKGROUND/PURPOSE: Recently, many reports have recommended surgical treatment for medication-related osteonecrosis of the jaw (MRONJ). However, MRONJ is more likely to occur in older patients with poor general condition and often necessitates extensive surgery, such as segmental mandibulectomy. The purpose of this study was to investigate treatment outcome of patients with MRONJ undergoing segmental mandibulectomy. MATERIALS AND METHODS: This retrospective study included 137 patients with medication-related osteonecrosis of the lower jaw who underwent surgical treatment at our hospital between 2011 and 2019. A total of 168 surgeries (155 marginal mandibulectomies and 13 segmental mandibulectomies) were performed. The relationship between clinical and imaging factors and the treatment outcome was investigated in the segmental mandibulectomy cases. RESULTS: Preoperative computed tomography (CT) showed osteolytic lesions in 13/13, periosteal reaction (PR) in 12/13, and osteosclerosis in 12/13 cases of segmental mandibulectomy. On postoperative CT, no residual osteolytic lesion and PR were noted, and 9 cases showed osteosclerosis. Twelve patients (92.3%) undergoing segmental mandibulectomy had complete healing, whereas the cure rate of those undergoing marginal mandibulectomy was 104/155 (67.1%). One patient with relapse after segmental mandibulectomy showed healing after an additional resection. In the patients who underwent segmental mandibulectomy, clinical symptoms, such as pain and purulent discharge, disappeared, and oral intake was possible. CONCLUSION: Segmental mandibulectomy is a treatment option for end-of-life care of refractory MRONJ, because it can eliminate clinical symptoms early. When performing segmental mandibulectomy, the area of the osteolytic lesion and periosteal reaction needs to be included.

Effects of sleep position on the treatment response of oral appliance for obstructive sleep apnea.

Objective: This retrospective study aimed to clarify the characteristics of positional obstructive sleep apnea (P-OSA) patients and to examine the relationship between sleep position and the efficacy of oral appliance (OA) therapy.Methods: Seventy-three patients who underwent polysomnography before and after OA therapy were divided into P-OSA or non-positional OSA (NP-OSA) and examined.Results: Forty-seven patients had P-OSA and 26 had NP-OSA. P-OSA was characterized by a relatively high ratio of supine to lateral apnea hypopnea index (AHI) because the lateral AHI of P-OSA was significantly lower than that of NP-OSA. OA therapy was more effective for P-OSA than NP-OSA. Younger age and the presence of P-OSA are useful as predictors of OA therapy efficacy.Discussion: Even for relatively severe OSA, in the case of younger age and/or P-OSA, the application of simple, cost-effective OA therapy might be recommended over other treatment modalities.

Imaging findings and treatment outcomes of a rare subtype of medication-related osteonecrosis of the jaw.

INTRODUCTION: In our previous study, we found a rare type of medication-related osteonecrosis of the jaw (MRONJ), which shows periosteal reaction (PR) at a site distant from osteolytic lesions or the extraction site (periosteal reaction dominant type, PRd type), even though the osteolytic lesions in the bone marrow are localized. The causes and treatment of MRONJ remain unclear; hence, this study aimed to describe the imaging and clinical features of the PRd type. MATERIALS AND METHODS: MRONJ patients who visited Nagasaki University Hospital between 2009 and 2020 and received conservative therapy as initial treatment were included in this study. The PR site, imaging findings, initial symptoms, outcome, and time to progression were examined. RESULTS: Among 59 MRONJ patients treated with conservative therapy, 38 did not show PR (PR- type), 15 showed PR near the osteolytic region (PR + type), and 6 had the PRd type. All patients with the PRd type had submental abscesses, and computed tomography (CT) images demonstrated PR on the lingual side of the anterior mandible. Osteolytic lesions progressed in 6/6 PRd type (100%), 5/15 PR + type (33.3%), and 2/38 PR- type (5.3%) patients. Time to progression for the osteolytic region on CT was short for the PRd type, at 56-148 days (median 79 days). CONCLUSION: Among the MRONJ types, the PRd type has a poor prognosis. Therefore, accumulating and analyzing more PRd cases in the future is warranted. This is the first report to describe the presence of this specific subtype of MRONJ.

Relationship between tooth extraction and development of medication-related osteonecrosis of the jaw in cancer patients.

Tooth extraction has been avoided since it has been considered a major risk factor for medication-related osteonecrosis of the jaw (MRONJ). However, MRONJ may also develop from tooth that is an infection source. This study aimed to clarify whether tooth extraction is a risk factor for the development of MRONJ in cancer patients receiving bone-modifying agents (BMAs). This retrospective observational study included 189 patients (361 jaws) from two hospitals. The risk factors of MRONJ were identified by comparing patient characteristics between those who did and did not develop MRONJ. Furthermore, the effect of tooth extraction during BMA therapy was analyzed after adjusting for confounding factors using the propensity score matching method. MRONJ occurred in 33 patients jaws. A longer duration of BMA administration, fewer number of teeth, presence of symptoms of local infection, and infected teeth were independent risk factors of MRONJ. However, tooth extraction during BMA therapy did not increase the risk. Propensity score matching analysis showed that tooth extraction significantly lowered the risk of MRONJ development. Teeth that can be an infection source increases the risk of MRONJ, and thus, they need to be extracted even during BMA administration.

Surgical strategy for medication-related osteonecrosis of the jaw (MRONJ) on maxilla: A multicenter retrospective study.

BACKGROUND/PURPOSE: Because the anatomy and the nature of the bone tissue between the mandible and maxilla are largely different, more site-specific studies are required to improve the healing rate on medication-related osteonecrosis of the jaw (MRONJ). The present study assessed maxillary MRONJ that was treated by surgery to understand its clinical characteristics, and to identify critical factors that influenced outcomes. MATERIALS AND METHODS: The medical records of 54 patients with maxillary MRONJ who underwent surgery were retrospectively reviewed. Variables related to the prognosis of MRONJ were extracted from the medical records and imaging, and were statistically analyzed. We also evaluated the concomitant maxillary sinusitis (MS) after the surgical treatment of MRONJ, based on CT evaluation and change of symptoms. RESULTS: The healing rate of surgery for maxillary MRONJ was 85.2%, which suggested that surgical treatment is an effective strategy for treating maxillary MRONJ. Multivariate analysis revealed that postoperative residual necrotic bone was a poor prognosticator for maxillary MRONJ. Among 10 patients who did not obtain healing of MS postoperatively, 8 patients showed an improvement. CONCLUSION: Our results indicate that surgical treatment is an appropriate strategy for maxillary MRONJ and complete resection of necrotic bone (i.e., extensive surgery) is needed to obtain complete healing of maxillary MRONJ. Concomitant MS tends to be healed or improved clinically in combination with the healing of maxillary MRONJ.

Periosteal reaction of medication-related osteonecrosis of the jaw (MRONJ): clinical significance and changes during conservative therapy.

PURPOSE: We previously reported that the periosteal reaction (PR) in medication-related osteonecrosis of the jaw (MRONJ) is a poor prognostic factor in surgical cases, but it is not clear how PR changes during conservative therapy. The purpose of this retrospective study was to compare computed tomography (CT) findings at the first visit and during follow-up visits in MRONJ patients subjected to conservative therapy and to investigate factors associated with the exacerbation of PR during conservative therapy. METHODS: Sixteen patients with MRONJ of the lower jaw who underwent conservative therapy and experienced a PR on CT images at the first visit and underwent CT examination again after 6 months or more were enrolled in the study. Clinical features and CT findings (extent of osteolytic lesion, extent of PR, type of PR, and changes during conservative treatment) were investigated. RESULTS: On the second CT scan, the osteolytic lesion improved in 4 patients, had not changed in 5, and deteriorated in 7, whereas the PR improved in 5 patients, had not changed in 4, and deteriorated in 7 patients. PR was significantly deteriorated in patients who continued to receive antiresorptive agents during conservative treatment and in patients with deteriorated osteolytic lesions. CONCLUSION: PR in MRONJ often expands during conservative therapy and the PR type progresses from the attached type to the gap type, and the irregular type, but discontinuation of antiresorptive agent may improve PR as well as osteolytic lesions.

Inhibitory effect of topical antibiotics/antiseptics administration on bacterial growth in the open wound of the jawbone surgery: Randomized controlled, preliminary study.

BACKGROUND/PURPOSE: TThe bone cavities after extirpation of cysts or tumor of the jawbone requires the insertion of gauze containing various antibiotics/antiseptics to minimize the risk of pain, bleeding, and surgical site infection (SSI). However, there have been few reports on the efficacy of topical administration of antibiotics/antiseptics to an open wound of the jawbone. To compare the inhibitory effects of topical povidone-iodine gel and tetracycline ointment on the jawbone wound bacterial growth after extirpation of cyst or tumor. MATERIALS AND METHODS: This is a preliminary, randomized controlled, open-labeled trial. Eighteen patients were randomly assigned into two groups. In povidone-iodine (PI) group, gauze mixed with povidone-iodine gel was inserted into the bone cavity wound, and in tetracycline (TC) group gauze mixed with tetracycline ointment was inserted after extirpation of cyst or tumor of the jaw bone. In both groups, gauze was removed 48 h after surgery, and examined by bacterial culture and real-time polymerase chain reaction (PCR) using primers detecting total bacteria and MRSA. RESULTS: The topical application of tetracycline ointment was superior to that of povidone-iodine gel concerning inhibitory effects of total bacteria and methicillin-resistant Staphylococcus aureus (MRSA). CONCLUSION: This preliminary study suggests that the insertion of gauze mixed with tetracycline ointment is recommended for bone wounds after extirpation of cyst or tumor of the oral cavity.

Effect of periosteal reaction in medication-related osteonecrosis of the jaw on treatment outcome after surgery.

INTRODUCTION: Surgical treatment in patients with medication-related osteonecrosis of the jaw (MRONJ) is superior to conservative treatment. However, treatment outcome in patients with periosteal reaction (PR) was significantly poorer than that of those without PR. The purpose of this retrospective study was to analyze the pathophysiology and clinical significance of PR in MRONJ. MATERIALS AND METHODS: Out of 181 patients with MRONJ undergoing surgery, 38 patients with PR were enrolled in the study. CT examinations, histological examinations, and bacteriological examinations using real-time polymerase chain reaction were performed, and the relationship among the opted surgical method, CT findings, and treatment outcome was investigated. RESULTS: The pattern of PR was classified into three types: type 1, new bone is formed parallel to the mandible, and no gap was evident between the mandible and new bone; type 2, new bone is formed parallel to the mandible, and a gap was evident between them; type 3, an irregular shape. Histological examinations revealed inflammatory tissue in the area visualized as a gap on CT. Bacteriological examination showed the presence of bacteria in the type 2 or type 3 PR. Complete cure was observed in 21 of 38 (55.3%) patients, which was lower than the cure rate of 73.4% in 143 patients without PR. The cure rate was significantly lower in cases with type 3 PR or with persistent osteolysis. CONCLUSIONS: It seems that complete resection of both osteolytic area and type 3 PR is necessary to obtain complete healing in patients undergoing marginal mandibulectomy.

Topical povidone iodine inhibits bacterial growth in the oral cavity of patients on mechanical ventilation: a randomized controlled study.

BACKGROUND: Topical 0.12% chlorhexidine has been used widely to prevent ventilator-associated pneumonia in patients undergoing mechanical ventilation. However, it is not approved for mucosal application in Japan. The aims of this study were to investigate if topical povidone iodine (i) inhibits bacterial growth and (ii) disrupts the balance of the oral microbiota. METHODS: This randomized controlled clinical trial included 23 patients who underwent mechanical ventilation in the intensive care unit. The patients were divided randomly into two groups: the intervention group (n = 16) and the control group (n = 7). All patients received oral cleaning with 3% hydrogen peroxide, followed by irrigation with tap water. The patients in the intervention group received 10% povidone iodine applied topically to the oral cavity. The concentration of total bacteria in the oropharyngeal fluid were determined before, immediately after, 1 h, 2 h, and 3 h after oral care using the Rapid Oral Bacteria Quantification System, which is based on dielectrophoresis and impedance measurements. The number of streptococci, methicillin-resistant Staphylococcus aureus, Streptococcus pneumoniae, Pseudomonas aeruginosa, Porphyromonas gingivalis, and Candida albicans before, immediately after, 1 h, and 3 h after oral care were estimated based on real-time polymerase chain reaction data. RESULTS: After irrigation of the oral cavity, the number of bacteria decreased, but increased again at 1 h after oral care in the control group; however, in the intervention group, the concentration of bacteria was significantly lower than that in the control group at 1 hour (p = 0.009), 2 h (p = 0.001), and 3 h (p = 0.001) after oral care. The growth of all bacterial species tested was inhibited in the intervention group at 3 h after oral care, suggesting that povidone iodine did not disturb the balance of the oral microbiota. CONCLUSIONS: Topical application of povidone iodine after cleaning and irrigation of the oral cavity inhibited bacterial growth in the oropharyngeal fluid of patients on mechanical ventilation while not disrupting the balance of the oral microbiota. TRIAL REGISTRATION: University Hospitals Medical Information Network Clinical Trials Registry (UMIN-CTR), UMIN000028307. Registered 1 September 2017.