How do different fixed and removable retainers compare for stabilizing tooth position after treatment with orthodontic braces?

2020 ◽  
Author(s):  
Sera Tort ◽  
Jane Burch
Keyword(s):  
Author(s):  
Masayoshi Uezono ◽  
Keiji Moriyama
Keyword(s):  

2018 ◽  
Vol 23 (2) ◽  
pp. 30-36
Author(s):  
Alberto Consolaro ◽  
Mauricio de Almeida Cardoso

ABSTRACT The teeth become very close to each other when they are crowded, but their structures remain individualized and, in this situation, the role of the epithelial rests of Malassez is fundamental to release the EGF. The concept of tensegrity is fundamental to understand the responses of tissues submitted to forces in body movements, including teeth and their stability in this process. The factors of tooth position stability in the arch - or dental tensegrity - should be considered when one plans and perform an orthodontic treatment. The direct causes of the mandibular anterior crowding are decisive to decide about the correct retainer indication: Should they be applied and indicated throughout life? Should they really be permanently used for lifetime? These aspects of the mandibular anterior crowding and their implication at the orthodontic practice will be discussed here to induct reflections and insights for new researches, as well as advances in knowledge and technology on this subject.


Author(s):  
Daniela E. Winkler ◽  
Marcus Clauss ◽  
Maximilian Rölle ◽  
Ellen Schulz-Kornas ◽  
Daryl Codron ◽  
...  

Dental microwear texture analysis (DMTA) is widely used for diet inferences in extant and extinct vertebrates. Often, a reference tooth position is analysed in extant specimens, while isolated teeth are lumped together in fossil datasets. It is therefore important to test whether DMT is tooth position specific, and if so, what the causes for wear differences are. Here we present results from controlled feeding experiments with 72 guinea pigs, which either received fresh or dried natural plant diets of different phytolith content (lucerne, grass, bamboo), or pelleted diets with and without mineral abrasives (frequently encountered by herbivorous mammals in natural habitats). We test for gradients in dental microwear texture along the upper cheek tooth row. Regardless of abrasive content, pelleted diets display an increase in surface roughness along the tooth row, indicating that posterior tooth positions experience more wear compared to anterior teeth. Guinea pigs feedings on plants of low phytolith content and low abrasiveness (fresh and dry lucerne, fresh grass) show almost no DMT differences between tooth positions, while individuals feeding on more abrasive plants (dry grass, fresh and dry bamboo) show a gradient of decreasing surface roughness along the tooth row. We suggest that plant feeding involves continuous intake and comminution by grinding, resulting in posterior tooth positions mainly processing food already partly comminuted and moistened. Pelleted diets require crushing, which exerts higher loads, especially on posterior tooth positions, where bite forces are highest. These differences in chewing behaviour result in opposing wear gradients for plant versus pelleted diets.


2019 ◽  
Vol 147 (11-12) ◽  
pp. 670-675
Author(s):  
Predrag Vucinic ◽  
Djordje Petrovic ◽  
Stojan Ivic ◽  
Sanja Vujkov

Introduction/Objective. Maxillary incisors, when exposed during smile, are one of the most important facial features. In an attempt to overcome limitations of standard cephalometric methods, Andrews described an approach to determine ideal anteroposterior (AP) position of maxillary central incisors in smiling profile in relation to the forehead. We compared traditional Steiner cephalometric method, using surrounding skeletal landmarks, to the method proposed by Andrews, with the aim of determining whether distant but very noticeable craniofacial structures can affect our impression of tooth position. Methods. The study comprised 90 randomly selected lateral cephalograms, divided into three groups according to maxillary central incisors AP position according to Steiner cephalometric norms. The AP relationship of the maxillary central incisors was measured as a perpendicular distance from facial axis point to the nasion A line and to the vertical line through forehead facial axis point respectively. Student?s t-test and Pearson?s correlation were used to compare tested variables. Results. There was statistically significant difference between two methods (p = 0.01108). According to the Steiner method 46.67% subjects had retrusive incisors and 53.33% subjects had protrusion. Andrews?s method showed different results; 35.56% subjects had retrusion, while 64.4% had protrusion. Conclusion. The method proposed by Andrews showed consistently more protrusion than the traditional cephalometric method according to Steiner. Slightly retruded position of maxillary central incisors according to Steiner analysis does not always imply poor facial esthetics, if they have favorable position to the forehead. Low levels of correlation indicate that we should never rely on just one set of parameters.


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