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BACKGROUND:Buccal multiloop appliance in the clinical treatment of Class III malocclusion has good results, but also exhibits some problems and deficiencies in the application process. OBJECTIVE:To summarize the clinical problems and corresponding solutions of buccal multiloop appliance. METHODS:A computer-based search of Wanfang, CNKI and PubMed databases were performed for articles related to buccal multiloop appliance published from 2000 to 2013. The key words were buccal multiloop, Class III malocclusion, clinical application in Chinese and English. RESULTS AND CONCLUSION:Compared with other appliances, the buccal multiloop appliance appears to have some unique advantages. The buccal multiloop appliance with the soft elastic role cannot only promote growth and development of the maxilary, but also inhibit the excessive growth of the maxilary and trigger mandibular functional shift, thereby achieving crossbite correction. Therefore, the buccal multiloop appliance can have good achievements in the clinical crossbite correction of the deciduous and permanent teeth. For patients with Class III malocclusion, the buccal multiloop appliance also shows good results, and the corresponding clinical problems and deficiencies appear to be resolved one by one accordingly. So the buccal multiloop appliance is highly efficient for crossbite correction.
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BACKGROUND:Buccal Multiloop Removable Appliance can interceptively correct mutiple adolescent malocclusions. But the clinical problem of Buccal Multiloop fatigue fracture is not solved yet. How to prolong the fatigue fracture cycle is stil in the research stage. OBJECTIVE: To study the effect of different temperature of heat treatment on the Buccal Multiloop fatigue fracture cycle, thereby to select a relatively optimal method to enhance the fatigue fracture cycle. METHODS: Thirty-five left HL-2 Buccal Mltiloops were divided into seven groups according to different ways of heat treatment. Each group consisted of five samples. They were an untreated group, three pre-bending groups (320, 420, 520℃ heat treatment before bending) and three post-bending groups (320, 420, 520℃ heat treatment after bending). The dental stainless steel wires and Buccal Multiloop were respectively treated by low-temperature annealing. The data were recorded and evaluated after the samples tested by the 3D Simulating Movement of TMJ Testing Machine. The features of fatigue fracture were observed by scanning electron microscope. RESULTS AND CONCLUSION: The mean values of the Buccal Multiloop fatigue fracture cycle from largest to smalest were as folows: 520℃ pre-bending group > 420℃ pre-bending group > 320℃ pre-bending group > untreated group > 520℃ post-bending group > 320℃ post-bending group > 420℃ post-bending group. The fatigue fracture cycle of Buccal Multiloop made of the dental stainless steel wires after 520℃ annealing treatment was longer than others. By the observation of scanning electron microscope, the fracture crack extension area had the tendency to expand, transient interruption was delayed and the tissue structure became more uniform.
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BACKGROUND:Concerning the problem of the ruptured phenomenon in clinic work of HL-1 and HL-2 Buccal Multiloops removable appliance, we invented HL-3 Buccal Multiloops. OBJECTIVE:Through the Buccal Multiloops Fatigue Testing Machine which can imitate oral movements, to compare the fatigue strength of the HL-2 and HL-3 Buccal Multiloops in the same condition. METHODS:A pair of the HL-2 or HL-3 Buccal Multiloops with the completely symmetrical size, symmetrical height and symmetrical direction was fixed on the Buccal Multiloops Fatigue Testing Machine which could simulate oral movements, then keep the Buccal Multiloops Fatigue Testing Machine working until any Buccal Multiloops broke. The cyclic loading times of this pair Buccal Multiloops was recorded. Scanning electron microscope was used to observe the appearance of broken end of the Buccal Multiloops. RESULTS AND CONCLUSION:The cyclic loading times of HL-3 Buccal Multiloops were more than HL-2 Buccal Multiloops (P < 0.01), suggesting that HL-3 Buccal Multiloops has stronger fatigue strength than HL-2 Buccal Multiloops. Scanning electron microscope observation showed that the fractures of HL-2 and HL-3 Buccal Multiloops al had the typical fatigue fracture morphology, indicating that the rupture of HL-2 and HL-3 Buccal Multiloops belongs to fatigue fracture. However, HL-3 Buccal Multiloops exhibited bigger crack compared with HL-2 Buccal Multiloops, the presence of running-in region, suggesting that HL-3 Buccal Multiloops reduced the probability of fatigue fracture and prolonged the time of fatigue fracture.
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BACKGROUND:Osseous deformity is one of the most common Jaw deformities in clinic, which give patients serious impact on functionality and aesthetics, so patients want to cure it strongly. Recently, Functional Magnetic System has played an increasingly important role in correcting osseous deformity because of its advantages, so it is gradual y known by people. OBJECTIVE:This article wil give a summary of Functional Magnetic System in the progress and deficiencies, in order to have a greater development in the field of correct osseous deformity. METHODS:We searched the PubMed database, from January 1990 to June 2013 with the key words of“magnetic, orthodontics”in English. An online search of CNKI database, Wanfang database, Chongqing VIP database from January 1990 to June 2013 was also conducted with the key words of“magnetic, orthodontics”in Chinese. RESULTS AND CONCLUSION:Functional Magnetic System is the combination of magnetic force and the traditional function correcting device, with the aid of attraction and repulsion, we could make up for the inadequacy in the treatment of Jaw osseous deformity, including the problems of length, width and height. With the development of magnetic materials and the research of magnetic materials, Functional Magnetic System wil have a bigger development.
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BACKGROUND: Imported self-locking brackets cost much. So it is necessary to develop low-cost and easy-to-operate domestic self-locking brackets.OBJECTIVE: To introduce a newly developed self-locking brackets, and investigate the frictional forces of the brackets. DESIGN, TIME AND SETTING: Biomechanical controlled analysis was performed in the Laboratory of Harbin Medical University in January 2004. MATERIALS: Self-made self-locking brackets and domestic conventional tie-wing stainless steel brackets; domestic Ni-Ti round wire, Australian stainless steel round wire, and domestic stainless steel rectangular wire. METHODS: Two kinds of brackets were combined with three kinds of arch wires. Under the drive of micromotor, pull sensor moved at 1 mm/min. An arch wire, which was ligated in the bracket, was dragged. Thus, teeth's shift was imitated.MAIN OUTCOME MEASURES: Waveshape was observed through the use of storage oscillograph and corresponding data were recorded. Frictional force was determined and compared.RESULTS: Under the same other conditions, no matter which kind of arch wires were combined with, tie-wing brackets produced greater frictional force than self-locking brackets (P < 0.001). Under the same other conditions, no matter which kind of brackets were combined with, Ni-Ti wire produced greater frictional force than Australian stainless steel round wire and domestic stainless steel rectangular wire (P < 0.001). In addition, domestic stainless steel rectangular wires produced greater frictional force than Australian stainless steel round wires (P < 0.001). CONCLUSION: Self-locking bracket produces low frictional force, so it is fit for orthodontic doctors to use the corrective force.