Experimental tooth movement under light orthodontic forces: rates of tooth movement and changes of the periodontium.
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AIM: To investigate light forces for experimental tooth movement. METHOD: Light orthodontic forces of 1.2, 3.6, 6.5, and 10 g force (gf) were applied for 14 days to move rat molars, and the effects of the forces on the rate of tooth movement and changes of the periodontium were examined. RESULTS: In the early period, despite the different levels of force used in each group, there were no significant differences in tooth displacement. From hour 56 to day 14, the tooth displacement in the 1.2 gf group was significantly smaller than that in the other groups and the rate was nearly constant. The rates of tooth displacement in the 3.6, 6.5, and 10 gf groups fluctuated repeatedly, while the orthodontic forces gradually decreased. CONCLUSION: Experimental tooth movement in rats, tipping without friction under light forces, were either constant or fluctuated in cycles of several days' duration. This is in contradiction to the three-phases-theory of tooth movement described in previous investigations using heavy forces. (+info)
Mandibular advancement splints and continuous positive airway pressure in patients with obstructive sleep apnoea: a randomized cross-over trial.
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This prospective, randomized, cross-over trial was designed to compare the efficacy of a mandibular advancement splint (MAS) with that of nasal continuous positive airway pressure (nCPAP) in patients with obstructive sleep apnoea (OSA). Twenty-four patients (20 males and four females) with mild to moderate OSA (AHI between 10 and 49 events per hour) were enrolled in the study. Each patient used both MAS and nCPAP, with the initial therapy being allocated at random. Treatment periods lasted for two months with a two-week wash-out interval between. Polysomnography was performed prior to the study and after each clinical intervention. Patient and partner questionnaires were used to assess changes in general health and daytime somnolence. The AHI decreased from 22.2 to 3.1 using nCPAP, and to 8.0 using the MAS (P < 0.001 for both devices) and there was no statistically significant difference between the two treatments. The Epworth Sleepiness Score (ESS) fell from 13.4 to 8.1 with nCPAP, and to 9.2 with MAS (P < 0.001), again with no differences between the use of MAS or nCPAP. The questionnaire data showed an improvement in general health scores (P < 0.001) after both treatments, but daytime sleepiness only improved significantly using nCPAP (P < 0.001). Despite this, 17 out of the 21 subjects who completed both arms of the study preferred the MAS. The splints were well tolerated and their efficacy suggests that the MAS may be a suitable alternative to nCPAP in the management of patients with mild or moderate OSA. (+info)
Mandibular advancement appliances and obstructive sleep apnoea: a randomized clinical trial.
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This randomized placebo-controlled cross-over trial assessed the effectiveness of a mandibular advancement appliance (MAA) in managing obstructive sleep apnoea (OSA). Twenty-one adults, with confirmed OSA, were provided with a maxillary placebo appliance and a MAA for 4-6 weeks each, in a randomized order. Questionnaires at baseline and after each appliance assessed bed-partners' reports of snoring severity (loudness and number of nights per week), and patients' daytime sleepiness (Epworth Sleepiness Score, ESS). The Apnoea Hypopnoea Index (AHI) and Oxygen Desaturation Index (ODI) were measured at baseline and with each appliance during single night sleep studies. Seventy-nine per cent of subjects wore their MAA for at least 4 hours at night. Sixty-eight per cent of subjects wore their MAA for 6-7 nights per week. Excessive salivation was the most commonly reported complication. One subject was unable to tolerate the MAA and withdrew from the study. Among the remaining 20 subjects, the MAA produced significantly lower AHI and ODI values than the placebo. However, although the reported frequency and loudness of snoring and the ESS values were lower with the MAA than the placebo, these differences were not statistically significant. When wearing the MAA, 35 per cent of the OSA subjects had a reduction in the pre-treatment ODI to 10 or less, while 33 per cent had an AHI of 10 or less. The MAA was less effective in the subjects with the most severe OSA (pre-treatment ODI > 50 and/or pre-treatment AHI > 50). (+info)
Chair-side procedure for connecting transpalatal arches with palatal implants.
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The present investigation examined a chair-side procedure for connecting a transpalatal arch (TPA) with palatal implants, which does not involve any laboratory work. This new technique was compared with the standard procedure in terms of the number of steps, the time required, and the cost. The total chair-side time needed with the standard procedure was 38 minutes, with the material costs amounting to [symbol: see text] 159.6. With the chair-side procedure the total time required was 55 minutes, and the cost of the material totalled [symbol: see text] 34.1. The chair-side procedure was derived from orthodontic treatment concepts and is independent of laboratory input. Its major advantage is that it does not require transfers, which necessitate additional steps. These steps, which are inevitable with the standard procedure, resulted in an unexpectedly high cost level and increased the total cost. The difference in the cost of the material between the two procedures amounted to [symbol: see text] 125.5 and timewise the difference was 17 minutes. Whilst TPA-implant connections can be made with both the standard and chair-side procedures, the standard procedure, although taking considerably less chair-side time, was four times more expensive than the chair-side procedure. (+info)
Invisible treatment of a Class III female adult patient with severe crowding and cross-bite.
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This article reports on the treatment for a 24 year 9 month adult female patient with severe skeletal Class III and crowding. As the patient wanted to wear an invisible appliance treatment we provided treatment with lingual brackets. (+info)
Moulding of the generate to control open bite during mandibular distraction osteogenesis.
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Distraction osteogenesis of the craniofacial skeleton has become a widely accepted, safe, and effective means of craniofacial reconstructive surgery. Despite excellent results in general, there are still some uncertainties related to the procedure, such as development of an anterior open bite (AOB) during mandibular distraction. The aim of this study was to examine whether 'moulding of the generate', i.e. use of intermaxillary elastics during the active distraction phase is possible to close the mandibular plane angle and open bite. Three subjects, 13- and 15-year-old males and a 7-year-old female, underwent mandibular linear and angular bilateral distraction osteogenesis with moulding of the generate. Lateral cephalograms were obtained before the introduction of elastics and following distraction, once the activation was stopped and the patients were ready for the consolidation phase. Conventional cephalometric measurements were used to assess possible changes in the mandibular plane angle and incisor position. Three different anchorage systems (dental, orthopaedic, and skeletal) were used for placement of the intermaxillary elastics. Cephalometric examination showed that the mandibular plane angle was decreased during active distraction osteogenesis with the introduction of elastics and angulation of the distraction device. Depending on the type of elastic anchorage system, smaller or greater amounts of extrusion of the incisors were noted. Moulding of the generate during active distraction can be performed to reduce the mandibular plane angle and open bite. To prevent unwanted dentoalveolar changes from occurring during elastic traction, skeletal rather than dental fixation of the elastics is recommended. Intrusive mechanics may be incorporated into the orthodontic appliances to balance extrusive force by the moulding elastics. (+info)
Evaluation of the effects of functional orthopaedic treatment on temporomandibular joints with single-photon emission computerized tomography.
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The aims of this investigation were to evaluate the temporomandibular joints (TMJs) with single-photon emission computerized tomography (SPECT) in subjects treated with a mandibular advancement repositioning splint (MARS), and to compare the results with the total effect on dento-facial morphology. The study was undertaken on 17 Class II division 1 malocclusion subjects (nine males, eight females) with mandibular retrusion. Ten patients (five males, five females) formed the treatment group and seven (four males, three females) were used as the control. SPECT was performed only in the treatment group. Cephalometric evaluation showed significant increases in NAPog (P < 0.001) and SNB (P < 0.05) angles. Increased bone formation in theTMJs was analysed with the aid of pre- and post-treatment scintigraphic studies. The results indicate that new bone formation in the mandibular condyles seems to contribute to the increase in mandibular prognathism resulting from functional jaw orthopaedics. (+info)
Inactivated periods of constant orthodontic forces related to desirable tooth movement in rats.
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AIM: To examine the effects of inactive periods of force on the amount of tooth displacement and root resorption during experimental tooth movement in rats. SAMPLE: Sixty 11-week-old male Sprague-Dawley rats. METHOD: The maxillary first molar (M1) was moved mesially using a removable titanium-nickel alloy closed coil spring for 14 days. The rats were divided into four groups with, 0, 1, 4, and 9 hours of inactivation per day. RESULTS: Tooth displacement in the 0- and 1-hour groups was significantly greater than that in the 9-hour group. The area of root resorption in the 4- and 9-hour groups was significantly less than that in the 0- and 1-hour groups. There was no significant difference in root resorption between 0- and 1-hour groups, and also between 4- and 9-hour groups. CONCLUSION: The distance of tooth displacement gradually decreased as the inactive period increased, whereas root resorption suddenly decreased between 1 and 4 hours of inactive orthodontic force. (+info)