Characteristics of tin-containing fluoride toothpastes related to erosive tooth wear protection.

OBJECTIVES: To assess the effect of different tin-containing toothpastes on the control of erosive tooth wear in enamel and dentin. METHODS: Enamel and dentin slabs were randomly distributed into 7 experimental groups (n = 10/substrate): C-: negative control (Artificial saliva); AmF (regular fluoridated toothpaste without tin); Sn-1 (SnF2/NaF); Sn-2 (SnF2/NaF/SnCl2); Sn-3 (SnCl2/NaF); Sn-4 (SnF2/SnCl2); Sn-5 (SnCl2/AmF/NaF/chitosan). Specimens were submitted to 5-day erosion-abrasion cycling. Surface loss (SL) was determined with an optical profilometer. Tin deposition on the tooth surfaces and some characteristics of the toothpastes (pH, potentially available F-, %weight of solid particles, and RDA) were also assessed. Data were statistically analyzed (α = 0.05). RESULTS: For enamel, the Sn-2 presented the lowest SL, not differing significantly from AmF, C+, and Sn-3. The SL of these groups was significantly lower than the C-, except for Sn-3. Sn-1 and Sn-4 were also not significantly different from C-. For dentin, C- significantly showed the highest SL values, whilst, Sn-1 presented the lowest SL, not differing significantly from AmF, Sn-2, C+, and Sn-3. There was a significant positive association between enamel SL and the pH and tin deposition. Dentin SL was significantly negatively associated with the %weight of solid particles and RDA. CONCLUSIONS: Most of the tin-toothpastes were able to exhibit some protection against ETW. In this process, the toothpastes characteristics play a role, as lower enamel SL was significantly associated with lower pH values and tin deposition; and lower dentin SL was associated with higher %weight of solid particles and RDA of the toothpastes. CLINICAL SIGNIFICANCE: Tin-containing toothpastes can be used for erosive tooth wear protection, but our study showed that their effect depends on the pH, amount of tin deposition, % weight of solid particles and RDA of the toohpastes.

Fluxo digital na montagem simplificada de bráquetes linguais / Digital workflow in the simplified assembly of lingual brackets

Introdução: Na técnica ortodôntica lingual os bráquetes são posicionados na face lingual dos dentes e por isso é conhecida como uma técnica difícil pela complexidade no posicionamento dos bráquetes. Durante a evolução dessa técnica surgiram muitas formas de montagem do aparelho lingual. A mais utilizada preconizava a confecção de um modelo de set up ortodôntico e, a transferência do aparelho para a boca do paciente por meio de moldeiras ou jigs, a fim de se realizar a colagem propriamente dita. Posteriormente, surgiu uma outra forma de montagem do aparelho lingual mais simplificada, a colagem seria realizada de forma direta, isto é, sobre a superfície lingual do esmalte, porém demandava maior habilidade do profissional. Também poderia ser feita no modelo gesso de má oclusão, sem a confecção de set up. Objetivos: Facilitar a técnica utilizando recursos tecnológicos com um scanner e um software para substituir alguns passos analógicos da montagem do aparelho lingual. Material e Método: Realiza-se a digitalização intraoral por meio de um scanner, onde são obtidos os modelos em arquivos STL, que inseridos no software junto aos arquivos STL dos bráquetes linguais serão posicionados na superfície virtual dos modelos digitais. Uma moldeira virtual de transferência será confeccionada em uma impressora 3D em resina, onde serão inseridos os bráquetes metálicos para a colagem propriamente dita. Conclusão: A montagem do aparelho lingual simplificada pode ser realizada com excelência pelos meios digitais em quase todos os passos.(AU)

Introduction: In lingual orthodontics technique the brackets are positioned on the teeth lingual surface, and for this reason it is known as a difficult technique due to the complexity of brackets positioning. During the evolution of this technique many forms of lingual appliance assembly were developed. The most used technique recommended to make an orthodontic set-up model and later to transfer the appliance to the patient's mouth using trays or jigs in order to perform the bonding itself. Subsequently, another and more simplified lingual appliance form emerged, in which the bonding would be performed directly, that is, on the lingual surface of the enamel, but it required greater skill from the professional. Also, it could be done on the cast model of malocclusion, without making the set-up model. Objectives: To facilitate the technique using technological resources with as a scanner and a software replacing some analogical steps in the assembly of the lingual device. Material and Method: Intraoral digitizing is performed by a scanner where the models are obtained in STL files, that inserted in the software together with the STL files of the lingual brackets will be positioned on the virtual surface of the digital models. A virtual transfer tray will be made of resin in a 3D printer where the metal brackets will be inserted for the actual bonding. Conclusion: The assembly of the simplified lingual device can be performed with excellence by digital means in almost all steps. (AU)