Changes in tongue-palatal contact during swallowing in patients with skeletal mandibular prognathism after orthognathic surgery.

This study aimed to evaluate improvement of tongue-palatal contact patterns during swallowing after orthognathic surgery in mandibular prognathism patients. Thirty patients with mandibular prognathism treated by orthognathic surgery (average age of 27 years, 3 months) and 10 controls (average age 29 years, 6 months) participated in this study. Tongue-palatal contact patterns of patients before and three months after surgery were evaluated by electropalatography (EPG) as well as controls. Whole total of tongue-palatal contact at 0.3, 0.2, and 0.1 sec before complete tongue-palatal contact during swallowing were evaluated. The duration of swallowing phases was also examined. Complete contact of tongue-tip in the alveolar part of individual artificial EPG plate were shown at 0.3, 0.2, and 0.1 sec before complete tongue-palatal contact in the controls, although incomplete contact in the alveolar part were shown at 0.3 sec in mandibular prognathism patients. Whole total of tongue-palatal contact at 0.3 and 0.2 sec before complete tongue-palatal contact was significantly lower in the patients before surgery than in the controls (p<0.05). However, these values increased after surgery. The duration of oral and pharyngeal phase was significantly longer in the patients before surgery than in the controls and the patients after surgery (p<0.01). This study demonstrated that the tongue-palatal contact pattern improved and the duration of oral and pharyngeal phase was shortened in mandibular prognathism patients during swallowing after orthognathic surgery. It is suggested that changes in maxillofacial morphology by orthognathic surgery can induce normal tongue movement during swallowing. (The data underlying this study have been uploaded to figshare and are accessible using the following DOI: https://doi.org/10.6084/m9.figshare.14101616.v1).

Effects of loxoprofen on the apical root resorption during orthodontic tooth movement in rats.

Studies have revealed that severe apical root resorption during tooth movement is caused by the noninfective inflammatory reaction of apical root tissues. We hypothesized that loxoprofen can suppress apical root resorption during tooth movement. Cyclic tensile force (CTF) of 10 kPa was applied to the human pulp cells for 48 hours by the Flexcell Strain Unit. Loxoprofen (10 and 100 µM) was added to the culture cells, and expression of cyclooxygenase (COX)-1, COX-2, interleukin (IL)-1ß, receptor activator of nuclear factor kappa-B ligand (RANKL), tumor necrosis factor (TNF)-α, and macrophage colony-stimulating factor (M-CSF) were examined. To determine the effects of loxoprofen sodium on apical root reabsorption during tooth movement, the upper first molars of 7-week-old rats were subjected to mesial movement by 10g force for 30 days with or without the oral administration of loxoprofen. Gene expression and protein concentration of COX-1, COX-2, IL-1ß, TNF-α, RANKL and M-CSF were significantly higher in the CTF group than in the control group. However, these levels were decreased by loxoprofen administration. After orthodontic tooth movement, the expression of IL-1ß, TNF-α, RANKL and M-CSF decreased in the loxoprofen group than in the control group by immunohistochemical staining. In comparison to control group, less number of odontoclasts and a decrease in the amount of apical root resorption was observed in the loxoprofen group. Many osteoclasts became visible on the pressure side of the alveolar bone in the both groups, and the amount of tooth movement did not show a significant difference. These findings demonstrate that severe apical root resorption may be suppressed by loxoprofen administration, without a disturbance of tooth movement.

RANKL and OPG expression: Jiggling force affects root resorption in rats.

OBJECTIVE: To immunohistochemically investigate the longitudinal changes in root resorption by jiggling force in experimental animal models. MATERIALS AND METHODS: Fifty-six 12-week-old male Wistar rats were used. The maxillary first molars were alternately moved in the buccal and lingual direction in 28 rats (experimental group) using an experimental appliance to produce jiggling forces of 10 g. In another 28 rats (control group), the maxillary first molars were moved in only the lingual direction with a force of 10 g. After 1, 3, 7, 10, 14, 17, and 21 days, the maxillae were resected and subjected to immunohistochemical analysis. The resorption area was quantified histomorphometrically and the number of odontoclasts on the root surface was counted. Expression of RANKL and OPG was also examined by immunohistochemical staining. RESULTS: The root resorption area and the number of odontoclasts were significantly greater in the experimental group than in controls. Odontoclasts were detected in the resorption lacunae and PDL in the experimental group, whereas osteoclasts were located only along the alveolar bone in controls. OPG was detected on the alveolar bone in the experimental group and on the root surfaces of the controls. CONCLUSIONS: Jiggling force is a critical factor in severe root resorption, affecting RANKL and OPG expression, which accelerates and inhibits odontoclastic induction, respectively.

Irradiation effects of low temperature multi gas plasma jet on oral bacteria.

The purpose of this study is to evaluate the sterilization effects of a newly developed low temperature multi gas plasma jet on oral pathogenic microorganisms (Streptococcus mutans [S. mutans], Lactobacillus fermentum [L. fermentum], Aggregatibacter actinomycetemcomitans [A. actinomycetemcomitans]). Plasma gas which generated from O2, N2, Ar and 50% (O2+N2) was irradiated to the microbes. Effect of O2 plasma irradiation on S. mutans under scanning electron microscopy (SEM) was also observed. O2 plasma was directly applied to dental plaque on human extracted tooth. Then, the depth of enamel resorption area was noted by nanoscale hybrid microscope. O2 had the best sterilizing effect for all microbes. The potent bactericidal effect of plasma irradiation was also observed by SEM. Decalcification of enamel was noted significantly lower in plasma irradiated tooth surface compared to no plasma exposure group. These findings revealed that multi gas plasma jet has great potential to be used for dental treatment.

A case of tooth autotransplantation after long-term cryopreservation using a programmed freezer with a magnetic field.

This case report describes the treatment of a skeletal Class III malocclusion with autotransplantation of a cryopreserved tooth. To gain an esthetic facial profile and good occlusion, extraction of bimaxillary premolars and surgical therapy were chosen. The patient had chronic apical periodontitis on the lower left first molar. Although she did not feel any pain in that region, the tooth was considered to have a poor prognosis. Therefore, we cryopreserved the extracted premolars to prepare for autotransplantation in the lower first molar area because the tooth would probably need to be removed in the future. The teeth were frozen by a programmed freezer with a magnetic field (CAS freezer) that was developed for tissue cryopreservation and were cryopreserved in -150°C deep freezer. After 1.5 years of presurgical orthodontic treatment, bilateral sagittal split ramus osteotomy was performed for mandible setback. Improvement of the facial profile and the occlusion were achieved in the retention phase. Six years after the initial visit, the patient had pain on the lower left first molar, and discharge of pus was observed, so we extracted the lower left first molar and autotransplanted the cryopreserved premolar. Three years later, healthy periodontium was observed at the autotransplanted tooth. This case report suggests that long-term cryopreservation of teeth by a CAS freezer is useful for later autotransplantation, and this can be a viable technique to replace missing teeth.

Effects of pulpectomy on the amount of root resorption during orthodontic tooth movement.

INTRODUCTION: Previous studies have revealed that orthodontic force affects dental pulp via the rupture of blood vessels and vacuolization of pulp tissues. We hypothesized that pulp tissues express inflammatory cytokines and regulators of odontoclast differentiation after excess orthodontic force. The purpose of this study was to investigate the effects of tensile force in human pulp cells and to measure inflammatory root resorption during tooth movement in pulpless rat teeth. METHODS: After cyclic tensile force application in human pulp cells, gene expression and protein concentration of macrophage colony-stimulating factor, receptor activator of nuclear factor kappa-B ligand, interleukin-1 beta, and tumor necrosis factor alpha were determined by real-time polymerase chain reaction and enzyme-linked immunoassay. Moreover, the role of the stretch-activated channel was evaluated by gadolinium (Gd(3+)) treatment. The upper right first molars of 7-week Wistar rats were subjected to pulpectomy and root canal filling followed by mesial movement for 6 months. RESULTS: The expression of cytokine messenger RNAs and proteins in the experimental group peaked with loading at 10-kPa tensile force after 48 hours (P < .01). Gd(3+) reduced the expression of these cytokine messenger RNAs and protein concentrations (P < .01). The amount of inflammatory root resorption was significantly larger in the control teeth than the pulpectomized teeth (P < .05). CONCLUSIONS: This study shows that tensile forces in the pulp cells enhance the expression of various cytokines via the S-A channel, which may lead to inflammatory root resorption during tooth movement. It also suggests that root canal treatment is effective for progressive severe inflammatory root resorption during tooth movement.

Cranial bone regeneration after cranioplasty using cryopreserved autogenous bone by a programmed freezer with a magnetic field in rats.

BACKGROUND: The purpose of this study was to develop a bone tissue bank using a programmed freezer with a magnetic field. Parietal bones were removed from rats and used for organ culture examination (non-cryopreserved, cryopreserved with a magnetic field (CAS) and cryopreserved without a magnetic field group). Next, other parietal bones were used for histological examination. The cryopreserved bones by a CAS freezer and dried bones were transplanted respectively. Control bones were replanted without cryopreservation. Animals were sacrificed at 4, 8, 12 and 24 weeks after surgery. After organ culture, the isolated osteoblasts from parietal bones which were cryopreserved by a CAS freezer can survive and proliferate as much as non-cryopreserved group. Histological examinations showed new bone formation in control and CAS group. These results suggest that bone tissue cryopreservation by CAS freezer can be successfully used for bone grafting which may be a novel option for regeneration medicine.

Cryopreservation of rat MSCs by use of a programmed freezer with magnetic field.

Mesenchymal stem cells (MSCs) can be used for the regeneration of various tissues and cryopreservation of MSCs is so important for regenerative medicine. The purpose of this study was to evaluate the influences of cryopreservation on MSCs by use of a programmed freezer with a magnetic field (CAS freezer). MSCs were isolated from bone marrow of rat femora. The cells were frozen by a CAS freezer with 10% dimethyl sulfoxide (Me2SO) and cryopreserved for 7 days at a temperature of -150 °C. Immediately after thawing, the number of survived cells was counted. The cell proliferation also examined after 48 h culture. Next, MSCs were frozen by two different freezers; CAS freezer and a conventional programmed freezer without magnetic field. Then, osteogenic and adipogenic differentiations of cryopreserved cells were examined. As a result, survival and proliferation rates of MSCs were significantly higher in CAS freezer than in the non-magnetic freezer. Alizarin positive reaction, large amount of calcium quantification, and greater alkaline phosphatase activity were shown in both the non-cryopreserved and CAS groups after osteogenic differentiation. Moreover, Oil Red O staining positive reaction and high amount of PPARγ and FABP4 mRNAs were shown in both the non-cryopreserved and CAS groups after adipogenic differentiation. From these findings, it is shown that a CAS freezer can maintain high survival and proliferation rates of MSCs and maintain both adipogenic and osteogenic differentiation abilities. It is thus concluded that CAS freezer is available for cryopreservation of MSCs, which can be applied to various tissue regeneration.

Gummy smile and facial profile correction using miniscrew anchorage.

This case report describes the treatment of a case involving a skeletal Class II facial profile with a gummy smile. While treating a facial profile and a gummy smile, the outcome may not always be successful with orthodontic therapy alone. For this reason, surgical therapy is often chosen to gain an esthetic facial profile and a good smile. However, sometimes the patients reject surgical treatment and an alternative method must be considered. Skeletal anchorage systems such as miniscrews are now frequently used for correcting severe malocclusion that should be treated by surgical therapy. In this case report, we treated a skeletal Class II malocclusion with a convex profile and a gummy smile using miniscrews, which were placed in the upper posterior and anterior areas. The active treatment period was 3.5 years, and the patient's teeth continued to be stable after a retention period of 36 months.

Effects of Lipid Peroxidation-Derived Products on the Growth of Human Colorectal Cancer Cell Line HT-29.

Epidemiologic investigations indicate a close relationship between colorectal cancer and fat intake. However, to date the effects of lipid peroxidation-derived products that are formed from fat (especially free or esterified unsaturated fatty acids) on the initiation or progression of colorectal cancer have not been investigated extensively. Therefore, in the present study, we examined the effects of fatty acids, fatty acid hydroperoxides and aldehydes on the growth of human colorectal cancer cell line HT-29. At concentrations of 1 and 10 microM, linoleic, arachidonic and eicosapentaenoic acids, and 13-hydroperoxyoctadecadienoic and 15-hydroperoxyeicosapentaenoic acids had no significant effects on the growth of HT-29 cells. 4-Hydroxynonenal and 4-hydroxyhexenal had no significant effects on the growth of HT-29 cells up to 10 microM, whereas 4-oxononenal potently inhibited HT-29 cell growth (1-10 microM, 16-85% inhibition). Further experiments concerning DNA fragmentation, expression levels of Bax and Bcl-2 mRNA, expression levels of pro-caspase-3 and caspase-3 proteins, and activity of caspase-3 suggested that 4-oxononenal may increase the sensitivity of HT-29 cells to apoptosis through a decreased expression level of Bcl-2 and then increased formation of caspase-3 from pro-caspase-3.