Plaque-removal effect of ultrafine bubble water: Oral application in patients undergoing orthodontic treatment.

During orthodontic treatment, plaque tends to form around fixed orthodontic appliances, which increases the risk of dental caries. It has been reported that ultarafine bubble with a diameter <1 µm water (UFBW) effectively removes organic matter. In addition, UFBW is harmless and stable for at least one month with refrigeration. The aim of this study was to examine the plaque-removal effect of ultrafine bubble water (UFBW) to establish a new method to prevent dental caries in patients during orthodontic treatment procedures. The in vitro study examined different concentrations of UFBW and compared the cleaning effect to that of existing mouthwashes. High-concentration UFBW (HUFBW) was most effective in cleaning. In the subsequent clinical study, HUFBW showed a significantly higher plaque-removal effect compared to distilled water (p<0.01). Thus, supplementary use of HUFBW could decrease the incidence of dental caries during orthodontic treatment.

Mandibular prognathism attenuates brain blood flow induced by chewing.

Mastication is closely related to brain function. Animal experiments have revealed that tooth loss has a negative influence on brain function. Clinical studies also suggest that normal occlusion is an essential factor for favorable brain function. Mandibular prognathism (MP) usually results in occlusal dysfunction. However, the relationship between MP and brain function remains unclear. In the present study, we examined the relationship between MP and brain function by measuring brain blood flow (BBF). Seventeen subjects with normal occlusion (NORM) and 25 patients with MP participated in this study. The number of occlusal contacts were counted. Electromyography of the masseter muscles during clenching was also recorded. BBF was measured with non-invasive functional near-infrared spectroscopy during calculation task and chewing task. The number of the occlusal contacts and masseter muscle activity were lower in MP compared with NORM. The calculation task increased BBF in both groups. The chewing task also increased BBF in the inferior frontal gyrus in both groups, although the increase in MP was smaller than in NORM. We discovered that patients with MP exhibited a smaller increase in BBF at the inferior frontal gyrus during chewing as compared with NORM. As such, MP would negatively affect brain function.

Lip Morphology in Patients With Facial Asymmetry Can Be Corrected by 2-Jaw Surgery.

PURPOSE: Surgical orthodontic patients with facial asymmetry frequently show asymmetry of the lips, and this is often a major complaint of patients. This study investigated whether lip asymmetry associated with the maxilla and mandible was improved when 2-jaw surgery was performed in surgical orthodontic treatment. MATERIALS AND METHODS: Inclusion criteria for this retrospective cohort study were 1) an anteroposterior maxillary relation defined as skeletal Class I; 2) menton (Me) tranverse deviation greater than 5.0 mm; 3) maxillary cant greater than 3.0°; and 4) 2-jaw surgery. Primary predictor variables in this study were skeletal morphologic measurements (Me deviation, maxillary cant, and maxillary distance ratio) before and after treatment. Outcome variables were lip morphology measurements (labial commissure distance, lip angle, and lip area). Additional variables included age and gender. Vertical distances, angles, and area of the upper and lower lips were measured and compared before and after treatment. Hard tissues were measured using posteroanterior cephalograms. Paired t test and correlation coefficients were calculated. RESULTS: Fourteen patients (4 men [28.5%] and 10 women [71.5%]; mean age, 29 yr) were included. Meaningful changes were observed in distance and angle measurements of the lips from before to after treatment. In area measurement, ratios of the area on the deviated side to that on the contralateral side for the upper and lower lips changed markedly and were close to 1.0 compared with before treatment. A relevant correlation was found between change in Me deviation and change in ratio of the height of the labial commissure. CONCLUSION: In cases of facial asymmetry caused by deviation of the maxilla and mandible, lip asymmetry can be adequately corrected by leveling the canted occlusal plane and positioning the Me toward the midline with 2-jaw surgery.

A New Approach to Maxillary Protrusion with an Unstable Mandibular Position Accompanied with Unidentified Complaints: Case Report.

This case report describes the importance of combining morphological and functional examination with psychological examination in the establishment ofstable mandibular position in the treatment of maxillary protrusion with unstable mandibular position accompanied by unidentified complaints, which ensures safe orthodontic treatment.

Traditional Japanese medicine daikenchuto improves functional constipation in poststroke patients.

Poststroke patients with functional constipation, assessed by the Rome III criteria, from 6 hospitals were recruited in a study on the effects of the traditional Japanese medicine Daikenchuto (DKT) on constipation. Thirty-four patients (17 men and 17 women; mean age: 78.1 ± 11.6 years) were randomly assigned to 2 groups; all patients received conventional therapy for constipation, and patients in the DKT group received 15 g/day of DKT for 4 weeks. Constipation scoring system (CSS) points and the gas volume score (GVS) (the measure of the intestinal gas volume calculated from plain abdominal radiographs) were recorded before and after a 4-week observation period. The total score on the CSS improved significantly in the DKT group compared to the control (P < 0.01). In addition, scores for some CSS subcategories (frequency of bowel movements, feeling of incomplete evacuation, and need for enema/disimpaction) significantly improved in the DKT group (P < 0.01, P = 0.049, and P = 0.03, resp.). The GVS was also significantly reduced in the DKT group compared to the control (P = 0.03). DKT in addition to conventional therapy is effective in treating functional constipation in poststroke patients. This study was a randomized controlled trial and was registered in the UMIN Clinical Trial Registry (no. UMIN000007393).

Reconstruction of a collapsed dental arch in a patient with severe periodontitis.

This case report describes the significance of orthodontic treatment in reconstruction of a collapsed dental arch and a malocclusion associated with severe periodontitis. A Japanese man (age, 40 years 7 months) had an anterior crossbite, a collapsed occlusion, and severe periodontitis. Orthodontic treatment included the following steps: (1) correction of the anterior crossbite, labial movement of the maxillary incisors, and intrusion and retraction of the mandibular incisors; (2) correction of the posterior crossbite on the left side, buccal movement of the maxillary left canine and first premolars, and intrusion and retraction of the mandibular first premolar into the space of the mandibular left canine; (3) correction of the crowding of the mandibular right buccal segment and alignment of the teeth after extraction of the mandibular right first molar with a periapical lesion; and (4) improvement of the occlusion, with reconstruction of an acceptable occlusion. When combined with restorative and prosthodontic treatment, a fairly good occlusion was obtained. Reevaluation of the treatment after 11 years showed that the occlusion and periodontal condition were maintained well without deepening of the pockets and further bone loss. Orthodontic treatment with a systematic approach helped to recover the occlusion and prevented the recurrence of periodontitis by acquiring a good oral environment and motivating the patient to maintain oral health.

Mechanism of active eruption of molars in adolescent rats.

The mechanism of active eruption of molars was examined in 36 male adolescent Wistar rats. Histological, histochemical [tetracycline (TC) labelling and alkaline phosphatase (ALP) activity], and immunohistochemical [transforming growth factor (TGF)-ß1, -ß2, and -ß3] investigations were conducted of the rat molar areas. Real-time reverse transcription-polymerase chain reaction (RT-PCR) for mRNA of TGF-ß was performed on the periodontal ligament (PDL) dissected out by laser capture microdissection. TC labelling lines showed that a considerable amount of bone formation occurred in the alveolar crest region, apical region, and intraradicular septum, indicating that the maxillary molars had moved downward. However, the periodontal fibres revealed a regular arrangement (alveolar crest, horizontal and oblique fibres) during the experimental period. This suggests that new formation of alveolar crest fibres and rearrangement of the periodontal fibres occurred in the PDL. ALP activity was intense on the bone surface and in the PDL. TGF-ß1 was also detected in osteoblasts and fibroblasts but less so in cementoblasts. Real-time RT-PCR also demonstrated significant expression of mRNA of TGF-ß1 in the PDL, indicating that TGF-ß1 was involved in active eruption. These results suggest that active eruption occurs in adolescent rats and can be managed by TGF-ß1.

Elimination of transverse dental compensation is critical for treatment of patients with severe facial asymmetry.

This case report describes the importance of eliminating transverse dental compensation during preoperative orthodontic treatment for a patient with severe facial asymmetry. The patient, a 17-year-old Japanese woman, had severe facial asymmetry involving the maxilla and the mandible, and extreme transverse dental compensation of the anterior and posterior teeth in both arches. Therefore, the main treatment objectives were elimination of the transverse dental compensation by orthodontic treatment and correction of the morphology of the maxilla and the mandible by orthognathic surgery. The preoperative orthodontic treatment resulted in sufficient elimination of the transverse dental compensation and movement of the teeth into their proper positions so that basal bone firmly supported them. LeFort I osteotomy and sagittal split ramus osteotomy were performed to correct the skeletal morphology. Facial asymmetry was dramatically improved, and a favorable occlusion was obtained. At 1 year 8 months after the surgical orthodontic treatment, the facial symmetry and occlusion remained favorable. The results suggest that sufficient elimination of transverse dental compensation in the maxillary and mandibular arches during preoperative orthodontic treatment is requisite for successful treatment of severe facial asymmetry.

Time-lapse observation of rat periodontal ligament during function and tooth movement, using microcomputed tomography.

The aim of this study was to observe the time-lapse changes in the rat periodontal ligament (PDL) during function and tooth movement. Under Nembutal anaesthesia, time-lapse changes in the thickness of the PDL of the first molars were investigated in five 12-week-old adolescent rats with microcomputed tomography. Three-dimensional (3D) images were reconstructed from the data. Histological observation was also performed, using undecalcified frozen sections of the maxillary first molar area. The PDL appeared as a radiolucent furrow on the 3D images. A slight change in the thickness of the PDL was observed 1 hour after initiation of orthodontic force loading, which became significant after 6 hours, with the appearance of pressure-tension zones during the tooth movement. These changes were more significant 3 days after orthodontic loading. Histological observation of the lingual cervical PDL (pressure zone) in nine 12- to 13-week-old rats demonstrated that the periodontal space had become narrow and the cellular elements appeared to be densely packed in the narrowed PDL 6 hours after orthodontic loading. Degeneration of tissues appeared 3 days after loading. Observation of the buccal cervical PDL (tension zone) demonstrated that the PDL was extended 6 hours after orthodontic force loading, and the extension continued for up to 3 days. Alkaline phosphatase activity was distributed in the PDL, except for the degenerating tissues in the pressure zone 3 days after loading. The results suggest that the periodontal reaction was initiated within 6 hours after orthodontic force loading, which was related to the structural changes of the PDL. The changes probably induced an early response in individual cells of the PDL.

A new idea and method of tooth movement using a ratchet bracket.

Since ideally effective tooth movement in orthodontics should occur without causing damage to the periodontal ligament (PDL), a new bracket with a ratchet-locking system, the 'Ratchet Bracket', was designed to produce tooth movement while maintaining blood circulation. To define the mechanism of the appliance, a histological study was carried out on four Beagle dogs (9 months old) and a clinical study on five female patients (11 years to 38 years 10 months of age). Five upper canines in the dogs were moved 1.82 mm per month. On light microscopic observations, vascular forms showed a round-oval shape, without undermining bone resorption. No root resorption was observed in the compressed PDL at days 1, 14, and 35 of the experimental period. On fluorescent images at day 46, distinctive bone formation was apparent at the tension side. In the clinical investigation, nine upper canines in the five female patients were moved 1.92 mm per month. A wide and long alveolar hard line was seen only on the tension side of the canines on dental radiographs, indicating bodily tooth movement, without obvious signs of root resorption in all subjects. Neither spontaneous pain nor pain during biting were reported. The findings indicate that use of the ratchet bracket could result in rapid and pain-free tooth movement with vascular clarity to maintain blood circulation in the PDL.

Exposure to pressure stimulus enhances succinate dehydrogenase activity in L6 myoblasts.

Contraction of skeletal muscle generates pressure stimuli to intramuscular tissues. However, the effects of pressure stimuli, other than those created by electricity or nerve impulse, on physiological and biochemical responses in skeletal muscles are unknown. The purpose of this study is to examine the effects of a pure pressure stimulus on metabolic responses in a skeletal muscle cell line. Atmospheric pressure was applied to L6 myoblasts using an original apparatus. Succinate dehydrogenase (SDH) activity was evaluated by colorimetric assay using tetrazolium monosodium salt. The amounts of 2-deoxy-[(3)H]glucose uptake and lactate release were measured. SDH activity was 2.6- to 2.9-fold higher in pressurized L6 cells than in nonpressurized L6 cells (P < 0.01), and 2-deoxy-[(3)H]glucose uptake was 2.2-fold higher (P < 0.001). In addition, the amount of released lactate decreased from 6.8 to 3.7 mumol/dish when pressure was applied (P < 0.001). In contrast, the intracellular lactate contents of the pressurized cells were higher than those of nonpressurized cells (P < 0.01). However, the total amount of released lactate and intracellular lactate was lower in the pressurized cells than in nonpressurized cells. These findings demonstrate that a pure pressure stimulus enhances aerobic metabolism in L6 skeletal muscle cells and raise the possibility that elevated intramuscular pressure during muscle activity may be an important factor in stimulating oxidative metabolic responses in skeletal muscles.

Phosphatidylinositol-dependent bond between alkaline phosphatase and collagen fibers in the periodontal ligament of rat molars.

Alkaline phosphatase (ALP) is anchored to the outer leaflet of the lipid bilayer via phosphatidylinositol (PI) and ALP activity has been localized in the plasma membrane of numerous tissues. In the periodontal ligament ALP activity is found in the collagen fibers in addition to the plasma membrane of the osteoblasts and fibroblasts. In this study, we examined the distribution of ALP activity in the periodontal ligament of rat molars and also examined whether the bond between ALP and collagen fibers is dependent on PI by using phosphatidylinositol-specific phospholipase C (PI-PLC). ALP activity was distributed in the periodontal ligament. The activity mirrored the distribution of collagen fibers in the periodontal ligament. Cytochemical analysis also demonstrated that ALP activity was located not only in the plasma membrane of fibroblasts, but also in the collagen fiber bundles and fibrils in the periodontal ligament. After treatment with PI-PLC, the loss of ALP activity in the periodontal ligament was observed histochemically, and the loss of ALP activity in the fibroblasts as well as in the collagen fiber bundles and fibrils was observed cytochemically. These results strongly indicate that the bond between ALP and the collagen fibers is also dependent on PI.

Calcification of degenerating tissues in the periodontal ligament during tooth movement.

OBJECTIVE: Calcification of degenerating tissues in the periodontal ligament (PDL) during tooth movement was investigated longitudinally. MATERIALS AND METHODS: Upper first molars of male Wistar rats were moved lingually for 1, 7 and 21 d, following which unfixed undecalcified sections of the lingual PDL (in the pressure zone) were examined histologically, histochemically (autoradiography and electron probe microanalysis). RESULTS: On d 1 of tooth movement, degenerating tissues, together with some calcified particles, were visible in the pressure zone of the lingual PDL. On d 7, substantial calcified aggregations were seen in the degenerating tissues, predominantly situated between the bone and root. This was confirmed by the 45Ca autoradiography. On d 21 of tooth movement, large calcified aggregations were still clearly evident between the bone and root. CONCLUSIONS: This calcification of the degenerating tissues is a self-defense response of the living body to prevent direct contact between alveolar bone and the tooth root during compression of the PDL, so preventing friction between them and the development of ankylosis.

Compensatory bone formation in young and old rats during tooth movement.

The aim of this study was to investigate compensatory lingual alveolar bone formation during tooth movement in young and old rats, using the vital bone marker tetracycline. Wistar male rats were separated into the following groups: 13-week-old rats without appliances (13C: control, n = 5), 60-week-old rats without appliances (60C: control, n = 5), 13-week-old rats with appliances (13E: experimental, n = 10), and 60-week-old rats with appliances (60E: experimental, n = 10). The upper first molars of the 13E and 60E groups were moved lingually using fixed appliances. On the third day of tooth movement, tetracycline (TC) was intra-peritoneally injected in all animals including the controls. On the 21st day of tooth movement, the animals were killed and unfixed, and undecalcified, 5-microm frozen frontal sections of the rat first molar areas in both control and experimental groups were examined under light and fluorescent microscopes. In the 13C group without tooth movement, tetracycline labelling lines were obvious in the alveolar crest, apical areas, and interradicular septum, indicating vertical alveolar bone growth. However, in the 60C control group, tetracycline labelling was almost undetectable throughout the alveolar bone. Although the lingual alveolar crest was resorbed from the periodontal side after lingual tooth movement, the sharp, bright labelling lines were still present from the crest to the lingual periosteal alveolar bone in the 13E group. In the 60E group the lines appeared in the lingual periosteal alveolar bone containing the crest, indicating considerable new bone formation. The results indicate that compensatory bone formation occurs in the alveolar crest area and, consequently, alveolar bone height is maintained, even in aged rats.