Abstract:Highly precise intraoral results may be achieved by transferring three-dimensional virtual setups for lingual retainers to the actual patients. This CAD/CAM strategy of making retainers can offer high predictability even in anatomically demanding regions and in the presence of limited space.
“…Despite these efforts, no recipe has yet been found to reliably prevent posttreatment changes. These may take the form of tooth positions relapsing toward the initial malocclusion, but another issue that is increasingly being discussed concerns changes in tooth position brought about by the retention system itself [4,9,30].…”
Section: Introductionmentioning
confidence: 99%
“…Hence Angle's critics suggested various concepts of improving the long-term stability of occlusal relationships. The approach proposed by Tweed sought to prevent relapse due to overexpansion of the dental arch by extracting premolars [3,30].…”
OBJECTIVES While permanent retention is today the method of choice to stabilize orthodontic treatment outcomes, recent studies have increasingly reported posttreatment changes in tooth position during permanent retention. We conducted this study to analyze changes in the anterior mandible, whether the changes follow an underlying movement pattern, and, aiming for a preventive strategy, whether any risk factors could be identified comparing findings with the pretreatment situations. METH-ODS We included 30 patients who had worn fixed Twistflex retainers (UK 3-3) extending from canine to canine in the mandible. Casts reflecting the intraoral situations before orthodontic treatment (T0), directly after completion of active therapy (T1), and 6 months later (T2) were scanned and superimposed using Imageware Surfacer software. Posttreatment changes (T2-T1) of tooth position within the retainer block were analyzed on 3D virtual models and were compared to pretreatment (T0) and treatment-related (T1-T0) findings to identify potential risk factors. RESULTS Almost all analyzed patients revealed three-dimensional changes in tooth position within the retainer block. Comparing these movements, we repeatedly found rotated retainer blocks in labio-oral direction, while the center of rotation was located at the first incisors. This pattern was associated with intercanine expansion and excessive overjet correction during orthodontic treatment. The canines underwent the most pronounced (rotational and translational) movements. CONCLUSIONS In general permanent lingual retainers are safe but in special clinical cases retainers can induce undesired tooth movement. Risk factors seem to be intercanine expansion and excessive overjet correction during orthodontic treatment. In specific cases an additional retention device might be needed.
AbstractObjectives. While permanent retention is today frequently the method of choice to stabilize orthodontic treatment outcomes, recent studies have increasingly reported posttreatment changes in tooth position during permanent retention. We conducted this study to analyze such changes in the anterior mandible, whether these follow an underlying movement pattern, and, aiming for a preventive strategy, whether any risk factors could be identified by comparing findings to the pretreatment situations.
Methods.We included 30 patients who had worn a fixed Twistflex retainer extending from canine to canine in the mandible. Casts reflecting the intraoral situations before orthodontic treatment (T0), directly upon completion of active therapy (T1), and 6 months into retention (T2) were scanned and superposed using Imageware Surfacer software. Posttreatment changes (T2−T1) in tooth position inside the retainer block were analyzed on 3D virtual models and were compared to pretreatment (T0) and treatment-related (T1−T0) findings to identify potential risk factors.Results. Almost all patients revealed three-dimensional changes in tooth position within the retainer block. On comparing these movements...
“…Despite these efforts, no recipe has yet been found to reliably prevent posttreatment changes. These may take the form of tooth positions relapsing toward the initial malocclusion, but another issue that is increasingly being discussed concerns changes in tooth position brought about by the retention system itself [4,9,30].…”
Section: Introductionmentioning
confidence: 99%
“…Hence Angle's critics suggested various concepts of improving the long-term stability of occlusal relationships. The approach proposed by Tweed sought to prevent relapse due to overexpansion of the dental arch by extracting premolars [3,30].…”
OBJECTIVES While permanent retention is today the method of choice to stabilize orthodontic treatment outcomes, recent studies have increasingly reported posttreatment changes in tooth position during permanent retention. We conducted this study to analyze changes in the anterior mandible, whether the changes follow an underlying movement pattern, and, aiming for a preventive strategy, whether any risk factors could be identified comparing findings with the pretreatment situations. METH-ODS We included 30 patients who had worn fixed Twistflex retainers (UK 3-3) extending from canine to canine in the mandible. Casts reflecting the intraoral situations before orthodontic treatment (T0), directly after completion of active therapy (T1), and 6 months later (T2) were scanned and superimposed using Imageware Surfacer software. Posttreatment changes (T2-T1) of tooth position within the retainer block were analyzed on 3D virtual models and were compared to pretreatment (T0) and treatment-related (T1-T0) findings to identify potential risk factors. RESULTS Almost all analyzed patients revealed three-dimensional changes in tooth position within the retainer block. Comparing these movements, we repeatedly found rotated retainer blocks in labio-oral direction, while the center of rotation was located at the first incisors. This pattern was associated with intercanine expansion and excessive overjet correction during orthodontic treatment. The canines underwent the most pronounced (rotational and translational) movements. CONCLUSIONS In general permanent lingual retainers are safe but in special clinical cases retainers can induce undesired tooth movement. Risk factors seem to be intercanine expansion and excessive overjet correction during orthodontic treatment. In specific cases an additional retention device might be needed.
AbstractObjectives. While permanent retention is today frequently the method of choice to stabilize orthodontic treatment outcomes, recent studies have increasingly reported posttreatment changes in tooth position during permanent retention. We conducted this study to analyze such changes in the anterior mandible, whether these follow an underlying movement pattern, and, aiming for a preventive strategy, whether any risk factors could be identified by comparing findings to the pretreatment situations.
Methods.We included 30 patients who had worn a fixed Twistflex retainer extending from canine to canine in the mandible. Casts reflecting the intraoral situations before orthodontic treatment (T0), directly upon completion of active therapy (T1), and 6 months into retention (T2) were scanned and superposed using Imageware Surfacer software. Posttreatment changes (T2−T1) in tooth position inside the retainer block were analyzed on 3D virtual models and were compared to pretreatment (T0) and treatment-related (T1−T0) findings to identify potential risk factors.Results. Almost all patients revealed three-dimensional changes in tooth position within the retainer block. On comparing these movements...
“…B. eines Positioners [28], Aktivators und Protrusionsgeräts, ist in ersten Versuchen beschrieben worden [29]. Ebenso ist die Fertigung von Retainern [30] mittels CAD/…”
Section: Rapid-prototyping-technologien In Der Kieferorthopädieunclassified
“…Meanwhile, coating with bigger thickness is prone to rupture in the use of the process, which can result in the waste of spraying material. With the rapid development of CAD/CAM technology [21][22][23] and the improvement of product quality requirements, optimization of the spray gun trajectory is with increasing interest. In order to meet the new requirements of spraying operation and the production target with high efficiency and the low cost, research on the new model and the optimization method of the spray gun is a hot spot.…”
The industrial robot plays a very important role in stabilizing and improving the quality of products, production efficiency, working conditions and the rapid upgrading of products. It is often composed of a mechanical body, control device, driving system and detection and sensing device, and can be used in three-dimensional space to complete integration of automatic production and processing equipment. Spraying robot is one of the most important advanced coating production and processing equipment. It has the advantages of considerable flexibility and wide working scope, high spraying quality and material utilization efficiency. Due to the increasing competition for the market share, it should minimize the cost continually to accomplish the producing process. For the spraying process, how to optimize the trajectory of the spray gun and the spray parameters are the key factors to reduce the material consumption and improve the efficiency. In this paper, the spray gun trajectory and spraying effect are studied, and the experimental results show that the spray trajectory and spray effect are available. The results can also be used in other fields to get better performance.
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