Hangeshashinto for prevention of oral mucositis in patients undergoing hematopoietic stem cell transplantation: a randomized phase II study.

PURPOSE: Oral mucositis (OM) is a side effect associated with cancer treatment. Hangeshashinto (HST), a Kampo medicine, was originally prescribed to treat diarrhea, gastritis, and stomatitis. Several reports have described the effects of HST for OM induced by chemotherapy in patients with gastric or colorectal cancer. In this study, the effects of HST for prevention of OM were investigated in patients undergoing hematopoietic stem cell transplantation (HSCT). METHODS: Thirty patients scheduled to receive allogeneic grafts were enrolled from July 2020 to December 2021. They were randomly assigned to two groups and instructed to wash their mouth using HST dissolved in saline solution or using only saline solution three times a day. The observation period was from the initiation date of the conditioning regimen to the date of engraftment, and the end point was the incidence of OM. RESULTS: Eighteen patients developed OM, the most severe of which was Grade (G)3. There was no significant difference in the incidence of OM between the HST group and the control group. However, a negative correlation tended to be observed between the duration using HST use and the duration of OM (G2-3: P = 0.027, G3: P = 0.047). CONCLUSIONS: The present study demonstrated that HST use did not clearly inhibit onset of OM but showed a tendency to inhibit OM exacerbation. However, further studies are necessary to fully understand the effects of HST on OM in patients undergoing HSCT. TRIAL REGISTRATION: This study was registered in the Japan Registry of Clinical Trials on 7 May 2020 (jRCTs071200012).

Effect of cytokines on osteoclast formation and bone resorption during mechanical force loading of the periodontal membrane.

Mechanical force loading exerts important effects on the skeleton by controlling bone mass and strength. Several in vivo experimental models evaluating the effects of mechanical loading on bone metabolism have been reported. Orthodontic tooth movement is a useful model for understanding the mechanism of bone remodeling induced by mechanical loading. In a mouse model of orthodontic tooth movement, TNF-α was expressed and osteoclasts appeared on the compressed side of the periodontal ligament. In TNF-receptor-deficient mice, there was less tooth movement and osteoclast numbers were lower than in wild-type mice. These results suggest that osteoclast formation and bone resorption caused by loading forces on the periodontal ligament depend on TNF-α. Several cytokines are expressed in the periodontal ligament during orthodontic tooth movement. Studies have found that inflammatory cytokines such as IL-12 and IFN-γ strongly inhibit osteoclast formation and tooth movement. Blocking macrophage colony-stimulating factor by using anti-c-Fms antibody also inhibited osteoclast formation and tooth movement. In this review we describe and discuss the effect of cytokines in the periodontal ligament on osteoclast formation and bone resorption during mechanical force loading.

Efficacy of perioperative oral care management in the prevention of surgical complications in 503 patients after pancreaticoduodenectomy for resectable malignant tumor: A multicenter retrospective analysis using propensity score matching.

BACKGROUND: Pancreaticoduodenectomy has been associated with a high mortality rate and significant postoperative morbidity. Recently, perioperative oral care management has been reported to be effective in preventing postoperative pneumonia and surgical site infection. In this study, we examined the effect of perioperative oral care management in reducing complications after pancreaticoduodenectomy, including surgical site infection. METHODS: This retrospective multicenter study included 503 patients who underwent pancreaticoduodenectomy at 8 facilities between January 2014 and December 2016. Among these, 144 received perioperative oral management by dentists and dental hygienists (oral management group), whereas the remaining 359 did not (control group). The oral care management program included oral health instructions, removal of dental calculus, professional mechanical tooth cleaning, removal of tongue coating, denture cleaning, instructions for gargling, and tooth extraction. The participants were matched using propensity scores to reduce background bias. Various factors were examined for correlation with the development of complications. RESULTS: The incidence of organ/space surgical site infection was significantly lower in the oral management group than in the control group (8.0% vs 19.6%, P = .005). Multivariable logistic regression analysis revealed that hypertension and lack of perioperative oral management were independent risk factors for organ/space surgical site infection. Lack of perioperative oral management had an odds ratio of 2.847 (95% confidence interval 1.335-6.071, P = .007). CONCLUSION: Perioperative oral care management reduces the occurrence of surgical site infections after pancreaticoduodenectomy and should be recommended as a strategy to prevent infections in addition to antibiotic use.

Immunological reaction in TNF-α-mediated osteoclast formation and bone resorption in vitro and in vivo.

Tumor necrosis factor- α (TNF- α ) is a cytokine produced by monocytes, macrophages, and T cells and is induced by pathogens, endotoxins, or related substances. TNF- α may play a key role in bone metabolism and is important in inflammatory bone diseases such as rheumatoid arthritis. Cells directly involved in osteoclastogenesis include macrophages, which are osteoclast precursor cells, osteoblasts, or stromal cells. These cells express receptor activator of NF- κ B ligand (RANKL) to induce osteoclastogenesis, and T cells, which secrete RANKL, promote osteoclastogenesis during inflammation. Elucidating the detailed effects of TNF- α on bone metabolism may enable the identification of therapeutic targets that can efficiently suppress bone destruction in inflammatory bone diseases. TNF- α is considered to act by directly increasing RANK expression in macrophages and by increasing RANKL in stromal cells. Inflammatory cytokines such as interleukin- (IL-) 12, IL-18, and interferon- γ (IFN- γ ) strongly inhibit osteoclast formation. IL-12, IL-18, and IFN- γ induce apoptosis in bone marrow cells treated with TNF- α in vitro, and osteoclastogenesis is inhibited by the interactions of TNF- α -induced Fas and Fas ligand induced by IL-12, IL-18, and IFN- γ . This review describes and discusses the role of cells concerned with osteoclast formation and immunological reactions in TNF- α -mediated osteoclastogenesis in vitro and in vivo.

Effects of anti-mouse RANKL antibody on orthodontic tooth movement in mice.

Background/purpose: Orthodontic tooth movement is achieved by alveolar bone remodeling, and therefore the balance of bone resorption and formation is important. Receptor activator of nuclear factor-κB ligand (RANKL) plays a crucial role in bone resorption. We previously reported that tumor necrosis factor-α (TNF-α) is also important in bone resorption during tooth movement. In this study, we focused on bone and root resorption during orthodontic tooth movement in mice using anti-mouse RANKL antibody (anti-mRANKL ab). Materials and methods: Anti-mRANKL ab was administered intraperitoneally to mice that subsequently underwent orthodontic tooth movement. After 10 days, tissues around the moved teeth were histologically evaluated. To confirm the effects of anti-mRANKL ab on TNF-α induced bone resorption, TNF-α was administered with and without anti-mRANKL ab into the supracalvaria and the sutures of the calvaria were histologically evaluated. Results: Orthodontic tooth movement was suppressed in mice treated with anti-mRANKL ab. Root resorption was observed after orthodontic tooth movement, but not in mice treated with anti-mRANKL ab. In the calvarial experiment, the number of TRAP-positive cells in the calvarial sutures was lower in mice administered TNF-α with anti-mRANKL ab than in mice administered TNF-α alone. Conclusion: Our findings suggest that anti-mRANKL ab suppressed orthodontic tooth movement. This needs to be considered when orthodontic tooth movement is required in patients using anti-RANKL antibody.

A preliminary study of suppression of candida infection by miconazole mucoadhesive tablets in oral or oropharyngeal cancer patients undergoing radiotherapy.

Elevated numbers of candida in the oral cavity often lead to oral candidiasis development in patients undergoing radiotherapy for oral or oropharyngeal cancer. This study aimed to verify the effect of miconazole mucoadhesive tablets on suppression of oral candida infection during radiotherapy. For this preliminary interventional study, miconazole mucoadhesive tablets were attached to the oral mucosa for 14 days from when grade 2 oral mucositis appeared in patients with oral or oropharyngeal cancer receiving radiotherapy, and the incidence of oral candidiasis was investigated. Various clinical factors were examined; univariate and multivariate Cox regression analyses were performed to investigate and compare the efficacy of this drug in preventing oral candidiasis with results of our previous study as historical control. Miconazole mucoadhesive tablets were administered to 18 patients, and oral candidiasis was observed in one patient (5.6%) after treatment completion. Among 144 historical control patients, 43 (29.9%) developed oral candidiasis. Multivariate Cox regression showed that miconazole mucoadhesive tablets significantly reduced oral candidiasis development during radiotherapy (p = 0.049, Hazard ratio 0.136, 95% confidence interval 0.019-0.994). This preliminary study suggests the efficacy of miconazole mucoadhesive tablets in preventing oral candidiasis in oral or oropharyngeal cancer patients treated with radiotherapy.Trial registration: Japan Registry of Clinical Trials (jRCT), jRCTs071190023. Registered 3 September, 2019.

Preventive effects of betamethasone valerate ointment for radiation-induced severe oral mucositis in patients with oral or oropharyngeal cancer: protocol for a multicentre, phase II, randomised controlled trial (Bet-ROM study).

INTRODUCTION: This is a randomised, multi-centre, open-label, phase II study to evaluate the efficacy of betamethasone valerate ointment on radiation-induced oral mucositis in patients with head and neck cancer undergoing concomitant radiotherapy with cisplatin or cetuximab. METHODS AND ANALYSIS: The trial will take place at seven hospitals in Japan. Patients will be randomised (1:1) into betamethasone and control groups after the occurrence of grade 1 oral mucositis. In the betamethasone group, patients will use betamethasone valerate ointment five times a day, in addition to usual oral hygiene guidance. The primary endpoint is the incidence and onset time of grade 3 oral mucositis. The secondary endpoints are the incidence and onset time of grade 2 oral mucositis, incidence and onset time of oral candidiasis, completion of radiation therapy and adverse events. Target accrual is 102 patients with a two-sided type I error rate of 5% and 80% power to detect an 80% risk reduction in the incidence of grade 3 oral mucositis. ETHICS AND DISSEMINATION: This study was approved by the Clinical Research Review Board of Nagasaki University (No. CRB20-009). All participants will be required to provide written informed consent. Findings will be disseminated through scientific and professional conferences and peer-reviewed journal publication. The datasets generated during the study will be available from the corresponding author on reasonable request. TRIAL REGISTRATION NUMBER: jRCTs071200013.

IL-12- and IL-18-mediated, nitric oxide-induced apoptosis in TNF-α-mediated osteoclastogenesis of bone marrow cells.

TNF-α has been recognized as an important factor for osteoclastogenesis and plays an important role in bone resorption under pathological conditions. IL-12 and IL-18, which are T-cell mediators, are also important inflammatory cytokines. We have reported that IL-12 and IL-18 induce apoptosis in bone marrow cells treated with TNF-α in vitro and that osteoclastogenesis is inhibited by the interaction of TNF-α-induced Fas and the IL-12-induced Fas ligand (FasL). However, the anti-FasL antibody could not completely inhibit apoptosis. Therefore, it is possible that IL-12 and IL-18 may also trigger some other apoptotic mechanisms. Nitric oxide (NO) may act as a mediator of the apoptotic effect. In this study, we examined whether NO causes the IL-12- and IL-18-induced apoptosis of bone marrow cells in TNF-α-mediated osteoclast formation. We found that NO production was induced in bone marrow cells cultured with IL-12 and IL-18 in the presence of TNF-α. When bone marrow cells were cultured with TNF-α, osteoclasts were formed. In contrast, when bone marrow cells were cultured with both TNF-α and IL-12 or IL-18, the adherent cells were induced to undergo apoptosis. Apoptosis was partially inhibited when bone marrow cells were treated with NO synthase inhibitors. Furthermore, IL-12 and IL-18 synergistically induced cell death and upregulated NO production in the presence of TNF-α. These results indicate that the simultaneous effects of TNF-α and IL-12 or IL-18 on bone marrow cells induce apoptosis and that apoptosis is induced by the production of NO.

Effects of a bioadhesive barrier-forming oral liquid on pain due to radiation-induced oral mucositis in patients with head and neck cancer: A randomized crossover, preliminary study.

BACKGROUND/PURPOSE: Bioadhesive barrier-forming oral liquid, is a recently developed medical material for the management of pain caused by oral mucositis associated with cancer radiotherapy or chemotherapy. The purpose of this study was to evaluate the effectiveness of this liquid in relieving pain resulting from radiation-induced oral mucositis in patients with head and neck cancer. MATERIALS AND METHODS: This randomized, crossover trial investigated the analgesic effects of bioadhesive barrier-forming oral liquid using dexamethasone ointment as a control. Fifteen patients with mild or moderate pain due to radiation-induced oral mucositis were randomly assigned to two groups. Group A applied dexamethasone ointment once on day 1, had a wash-out period on day 2, and used bioadhesive barrier-forming oral liquid once on day 3. Conversely, group B used bioadhesive barrier-forming oral liquid on day 1, had a wash-out period on day 2, and applied dexamethasone ointment once on day 3. The effectiveness in relieving pain was compared between the two groups. RESULTS: One patient reported nausea immediately after the application of bioadhesive barrier-forming oral liquid and was therefore excluded from the analysis. Dexamethasone ointment and bioadhesive barrier-forming oral liquid relieved pain in 85.7% and 71.4% patients, respectively (p = 0.682). Nine patients wished to continue dexamethasone ointment after the study, while only five wished to continue bioadhesive barrier-forming oral liquid. CONCLUSION: Our findings suggest that the analgesic effect of bioadhesive barrier-forming oral liquid is comparable or inferior to that of dexamethasone ointment in patients with radiation-induced oral mucositis. Further studies are needed to verify these findings.

IL-18 inhibits TNF-alpha-induced osteoclastogenesis possibly via a T cell-independent mechanism in synergy with IL-12 in vivo.

It has recently been reported that tumor necrosis factor (TNF)-alpha has the ability to accelerate osteoclastogenesis. We previously reported that the proinflammatory cytokine interleukin (IL)-18 inhibits TNF-alpha-mediated osteoclastogenesis in mouse bone marrow cultures. In the present study, the effect of IL-18 on TNF-alpha-mediated osteoclastogenesis was investigated in vivo. We administered TNF-alpha with or without IL-18 into the supracalvaria of mice. The number of osteoclasts in the suture of the calvaria was increased in mice administered TNF-alpha. The number of osteoclasts in mice administered both TNF-alpha and IL-18 was lower than that in mice administered TNF-alpha alone. We previously showed that IL-12 and IL-18 synergistically inhibit TNF-alpha-mediated osteoclastogenesis in vitro. To assess the ability of these two cytokines to synergistically inhibit TNF-alpha-induced osteoclastogenesis in vivo, mice were administered the two cytokines at doses that did not inhibit osteoclast formation. The combination of IL-12 and IL-18 markedly inhibited TNF-alpha-induced osteoclastogenesis in vivo. To evaluate how IL-12 and IL-18 synergistically affect TNF-alpha-induced osteoclastogenesis, the IL-18 receptor (IL-18R) and IL-12R expression levels were analyzed by RT-PCR in bone marrow cells cultured with IL-12 or IL-18. IL-18R mRNA was increased in cells cultured with IL-12, while IL-12R mRNA was increased in cells cultured with IL-18. In addition, IL-18 inhibited TNF-alpha-induced osteoclastogenesis in mice with T-cell depletion caused by anti-CD4 and anti-CD8 antibodies. The present results suggest that IL-18 may inhibit TNF-alpha-mediated osteoclastogenesis in vivo via a T cell-independent mechanism.

Evaluation of the efficacy of low concentration fluoride gel using custom trays to prevent radiation-related dental caries in patients with head and neck cancer: protocol for a randomised controlled phase III trial (FluCar study).

INTRODUCTION: The present study is a randomised, multicentre, open-label, phase III study, to evaluate the efficacy of low concentration of fluoride gel, applied using custom trays, in preventing radiation-related dental caries in patients with head and neck cancer who have undergone or are undergoing radiotherapy. METHODS AND ANALYSIS: Patients will be randomised into fluoride and control groups (1:1 ratio). In the fluoride group, patients will wear custom trays loaded with 0.145% fluoride gel after brushing every night while sleeping. In the control group, patients will receive oral hygiene instructions as usual. Patients in both the groups will be followed up every 3 months for 1 year. The primary endpoint is the incidence of newly developed dental caries. Target accrual is 80 patients with a two-sided type I error rate of 5% and 80% power to detect 80% risk reduction. ETHICS AND DISSEMINATION: This study was approved by the Clinical Research Review Board in Nagasaki University The protocol of this study was registered at Japan Registry of Clinical Trials (jRCT) and University hospital Medical Information Network Clinical Trials Registry (UMIN). The datasets generated during the current study will be available from the corresponding author on reasonable request. TRIAL REGISTRATION NUMBERS: jRCTs 072190039 and UMIN000041426.

Prevention of dental caries by regular overnight application of a low-concentration fluoride gel loaded in a custom tray in patients undergoing radiotherapy for head and neck cancer: A preliminary study.

BACKGROUND: Some studies have reported topical application of 1.0%-2.0% fluoride gel in a custom tray for 4-5 minutes every day for the prevention of radiation-related dental caries. However, in Japan, the concentration of fluoride used by patients is limited to less than 0.15%. The efficacy of a low-concentration fluoride gel in a custom tray for the prevention of radiation-related dental caries has not been investigated. Methods and Material: In this preliminary study, we enrolled 13 patients with head and neck cancer who underwent radiotherapy. They wore a custom tray containing 0.145% sodium fluoride gel during sleep every night and were examined for newly developed dental caries 1 year later. Results: No new dental caries were found in the 13 patients 1 year after radiotherapy, and no adverse events were observed. CONCLUSIONS: We conclude that low-concentration fluoride gel in a custom tray during sleep could prevent radiation-related dental caries, and we plan to conduct a multi-center phase III randomized controlled trial to examine the efficacy of this method for the prevention of radiation-related dental caries.

Risk factors associated with the development of aspiration pneumonia in patients receiving radiotherapy for head and neck cancer: retrospective study.

BACKGROUND: Patients with head and neck cancer who are receiving radiotherapy can develop aspiration pneumonia. Determination of the incidence of aspiration pneumonia and the associated risk factors could facilitate the identification of high-risk patients. METHODS: In this retrospective study, we determined the incidence of aspiration pneumonia in 357 patients receiving radiotherapy along with oral care for head and neck cancer. We also performed univariate and multivariable logistic regression analyses to investigate the risk factors for this complication. RESULTS: The incidence of aspiration pneumonia was 17.6%. Hypopharyngeal cancer, grade 3 oral mucositis, and nasogastric tube feeding were independent risk factors. Moreover, the development of aspiration pneumonia was one of the major effects on the discontinuation of radiotherapy. CONCLUSION: Approximately, one-sixth of the patients developed aspiration pneumonia despite appropriate oral care during radiotherapy for head and neck cancer. Aspiration pneumonia during radiotherapy could adversely affect head and neck cancer management.

A TNF receptor loop peptide mimic blocks RANK ligand-induced signaling, bone resorption, and bone loss.

Activating receptor activator of NF-kappaB (RANK) and TNF receptor (TNFR) promote osteoclast differentiation. A critical ligand contact site on the TNFR is partly conserved in RANK. Surface plasmon resonance studies showed that a peptide (WP9QY) that mimics this TNFR contact site and inhibits TNF-alpha-induced activity bound to RANK ligand (RANKL). Changing a single residue predicted to play an important role in the interaction reduced the binding significantly. WP9QY, but not the altered control peptide, inhibited the RANKL-induced activation of RANK-dependent signaling in RAW 264.7 cells but had no effect on M-CSF-induced activation of some of the same signaling events. WP9QY but not the control peptide also prevented RANKL-induced bone resorption and osteoclastogenesis, even when TNFRs were absent or blocked. In vivo, where both RANKL and TNF-alpha promote osteoclastogenesis, osteoclast activity, and bone loss, WP9QY prevented the increased osteoclastogenesis and bone loss induced in mice by ovariectomy or low dietary calcium, in the latter case in both wild-type and TNFR double-knockout mice. These results suggest that a peptide that mimics a TNFR ligand contact site blocks bone resorption by interfering with recruitment and activation of osteoclasts by both RANKL and TNF.

An M-CSF receptor c-Fms antibody inhibits mechanical stress-induced root resorption during orthodontic tooth movement in mice.

OBJECTIVE: To examine the effect of anti-c-Fms antibody on odontoclastogenesis and root resorption in an orthodontic tooth movement mouse model. MATERIALS AND METHODS: We used orthodontic tooth movement in which an Ni-Ti coil spring was inserted between the upper incisors and the upper first molar. Root resorption occurred in this model. Anti-c-Fms antibody was injected daily into a local site for 12 days during mechanical loading. Odontoclastogenesis and root resorption were assessed by histology and scanning electron microscopy. RESULTS: The anti-c-Fms antibody significantly inhibited odontoclastogenesis and root resorption during orthodontic tooth movement. CONCLUSION: M-CSF and/or its receptor is a potential therapeutic target in mechanical stress- induced odontoclastogenesis, and injection of an anti-c-Fms antibody might be useful for inhibition of mechanical stress-induced root resorption during orthodontic tooth movement.

Influence of bisphosphonates on orthodontic tooth movement in mice.

Mechanical stress such as orthodontic tooth movement induces osteoclastogenesis. Sometimes, excessive mechanical stress results in root resorption during orthodontic tooth movement. It has been reported that bisphosphonate inhibits osteoclastogenesis. Recently, there have been concerns for orthodontic patients receiving bisphosphonates. Thus, the aim of this study was to investigate the effect of bisphosphonates on orthodontic tooth movement and root resorption in mice. A nickel-titanium (Ni-Ti) closed coil spring delivering a force of 10 g was inserted between the upper anterior alveolar bone and the first molar in 8-week-old male C57BL/6 mice. Bisphosphonate (2 microg/20 microl) was injected daily into a local site adjacent to the upper molar. After 12 days, the distance the tooth had moved was measured. The number of tartrate-resistant acid phosphatase (TRAP)-positive cells was counted as osteoclasts in histological sections. Root resorption was assessed by scanning electron microscopy. The data were analysed with a Student's t-test. The orthodontic appliance increased the number of osteoclasts on the pressure side and mesial movement of the first molar. Bisphosphonates reduced the amount of tooth movement and the number of osteoclasts. In addition, they also reduced root resorption on the pressure side. Bisphosphonates inhibit orthodontic tooth movement and prevent root resorption during orthodontic tooth movement in mice. These results suggest that bisphosphonates might have an inhibiting effect on root resorption during orthodontic tooth movement in humans and that they may interrupt tooth movement in orthodontic patients undergoing treatment, thus altering the outcome of treatment.

Effects of the changes in the condylar long axis angle and condylar position on temporomandibular symptoms after intraoral vertical ramus osteotomy: a preliminary study.

OBJECTIVE: This study was conducted to characterize the effects of the changes in the condylar long axis and position on temporomandibular symptoms with respect proximal segment position after intraoral vertical ramus osteotomy (IVRO). STUDY DESIGN: Twenty Japanese patients with diagnosed jaw deformity underwent IVRO without internal fixation. Long-term changes in condylar long axis and position were assessed during postoperative follow-up examinations by using computed tomography, and t tests were performed for comparison. In addition, changes in temporomandibular symptoms were examined. RESULTS: The degree of axial rotation of the proximal segment changed significantly when the proximal segment was located laterally. Downward changes in condylar position significantly differed when the proximal segment was located posterolaterally. Forward changes in condylar position significantly differed when the proximal segment was located laterally; moreover, when the proximal segment was located laterally, temporomandibular symptoms disappeared. CONCLUSIONS: Lateral location of the proximal segment may be an important factor in the positive effects of IVRO, with respect to temporomandibular symptoms.

Effects of perioperative oral care on prevention of postoperative pneumonia after lung resection: Multicenter retrospective study with propensity score matching analysis.

BACKGROUND: Postoperative pneumonia can be a fatal complication that may occur after lung resection in cancer patients. Some reports have shown that the incidence of postoperative pneumonia is decreased after esophageal surgery by perioperative oral care; however, there exist no data to suggest that a lack of perioperative oral care can be a risk factor for postoperative pneumonia after lung resection. To investigate the association between the preventive effect of oral care and postoperative pneumonia, we conducted a multicenter, retrospective study of lung cancer patients who underwent lung resection. METHODS: Between January 2014 and December 2016, a total of 721 patients underwent lung resections at 1 of the 6 hospitals included in our study. Among 721 patients, 280 (38.8%) received perioperative oral care, and the remaining 441 (61.2%) did not receive any such care. Propensity score matching was performed to minimize selection biases associated with the comparison of retrospective data between the oral care and control groups. RESULTS: Of the 721 patients, 54 (7.5%) experienced postoperative pneumonia involving 13 of the 280 patients (4.6%) in the oral care group and 41 of the 441 patients (9.3%) in the control group (P = .02). On propensity score analysis, a significant difference was also found between oral care intervention and incidence of postoperative pneumonia (P = .002). CONCLUSION: Our results suggest that perioperative oral care is an effective method to decrease the occurrence of postoperative pneumonia in patients who have undergone lung resection.

Expression of heat shock protein 47 in the periodontal ligament during orthodontic tooth movement.

The aim of this study was to investigate the kinetics of heat shock protein 47 (HSP47) and proliferating cell nuclear antigen (PCNA) immunohistochemistry in periodontal ligament (PDL) cells during orthodontic tooth movement in a mouse model. An orthodontic appliance was set between the upper incisors and the upper left first molar. The mice were killed 2, 6 and 10 days after initiation of orthodontic tooth movement. Computer-assisted image analysis was used to compare the quantitative expression of HSP47 in the PDL. HSP47 expression was significantly higher on the tension side 2 days after application of the appliance, whereas no significant change was observed on the pressure side at any time point. Furthermore, the PCNA labelling indices of PDL cells were increased significantly on the tension side 6 and 10 days after application of the appliance, and on the pressure side 2, 6 and 10 days after application of the appliance. These data suggest that collagen is metabolised predominantly on the tension side, and that PDL cells actively proliferate on both the tension and pressure sides during orthodontic tooth movement.

Force magnitude and duration effects on amount of tooth movement and root resorption in the rat molar.

OBJECTIVE: To test the hypothesis that there is no difference in the effect of different continuous moderate to very heavy forces on root resorption or amount of tooth movement. MATERIALS AND METHODS: In the study, 10, 25, 50 and 100 g mesial force were applied to the maxillary first molars of rat using nickel titanium closed-coil springs for 3 days, 14 days, and 28 days. The molars were extracted and the surface areas of the root resorption craters were measured using scanning electron microscope. The depths of the root resorption craters were measured using a three-dimensional laser scanning microscope. Tooth movement of the maxillary first molar was measured in relation to the maxillary second molar on digitized lateral cephalometric radiographs. RESULTS: Three days after force application, the tooth movement was not proportionally related to force magnitude. However, 14 days of force application resulted in significantly more tooth movement in the 10, 25, and 50 g force groups than in the 100 g force group. A force application of 10 g produced significantly more tooth movement at 28 days than all the other three force applications. The largest and deepest resorption craters were observed in the disto-buccal root followed by disto-palatal, middle-buccal, middle-palatal, and mesial root. Root resorption and tooth movement increased over time from 3 to 28 days. As heavier forces were applied, greater root resorption occurred. CONCLUSION: The hypothesis is rejected. The light mesially oriented forces, as applied in this study, produced more tooth movement and less root resorption compared with heavier forces.