Effect of different brushing parameters on erosive tooth wear in primary bovine enamel and dentin.

This in-vitro study aimed to analyse the effect of brushing and different brushing parameters (kind of toothpaste, kind of toothbrush, brushing force) on erosive tooth wear of primary bovine enamel and dentin. Specimens were prepared from primary bovine enamel or dentin (each group n = 12) and cyclically eroded (6 × 60 s/d, citric acid, pH 2.4) and brushed with children's toothbrushes (2 × 15 s/d) over 5 days. The brushing parameters under investigation were: toothpaste (fluoridated, fluoride-free), toothbrush (manual; rotating-oscillating and sonic, each at two different activation modes) and brushing force (1 N, 2 N). Specimens that were only eroded and not brushed served as controls. Enamel and dentin wear was quantified using widefield confocal microscopy. Statistical analysis was performed using three- and one-way ANOVAs followed by Scheffe's (enamel) or Tamhane's (dentin) post-hoc tests (p < 0.05). Brushing with the fluoridated toothpaste was able to significantly reduce erosive wear in enamel (by 15 to 37%, 6 of 10 groups) and in dentin (by 58 to 72%, all groups), while brushing with the fluoride-free toothpaste was not different from the controls. Considering the kind of toothpaste and brushing force, slight differences between the toothbrushes were observed in enamel, but not in dentin. Within the same toothbrush and activation mode, almost no differences between 1 and 2 N brushing force were detected. In conclusion, erosive tooth wear on primary bovine dental hard tissue mainly depends on the kind of toothpaste, rather than on the kind of toothbrush and the brushing force.

Tooth surface loss: causes, management, and prevention.

OBJECTIVES: Tooth wear, also referred to as tooth surface loss, occurs due to causes other than caries. This involves the loss of hard tissues, namely enamel, dentin, and/or cementum. Types of tooth wear/tooth surface loss are abrasion, abfraction, attrition, and erosion. These multifactorial conditions can be caused by factors such as lifestyle, diet, or even habits, and may not be symptomatic. The focus of this article is to provide clinicians with detailed examples and explanations of the causes of tooth loss to aid in early diagnosis. Through early identification, the preventive measures outlined can be implemented to avoid excessive tooth wear. The provision of a treatment flowchart and general treatment recommendations aims to help clinicians determine when to restore these lesions and the most appropriate treatment measures for the four types of wear. METHOD AND MATERIALS: The PubMed (MEDLINE) search engine was used to gather information on teeth restricted to a 5-year period (26 August 2018 to 25 July 2022). Only English-language studies and reviews with the best balance of sensitivity and specificity were considered. A Boolean search of the PubMed dataset was implemented to combine a range of keywords: ("tooth wear" OR tooth attrition OR tooth erosion OR tooth abrasion OR tooth abfraction). Additional articles were selected through Google Scholar. RESULTS: By this process, many articles and studies were obtained, and the 48 most relevant published studies were chosen and used in the current review. CONCLUSION: Tooth wear affects an increasing number of individuals and can have detrimental effects physically, mentally, and emotionally. It is important to stress early diagnosis and management of tooth wear through monitoring, prevention, and treatment where indicated.

The effect of location/site on polished human enamel after mechanical and chemical wear.

OBJECTIVE: To compare profilometry and microhardness of polished occlusal and buccal human enamel following a mechanical and chemical wear regime. METHODS: Enamel from polished human molars were sectioned into buccal and occlusal surfaces and randomly allocated into two groups (n = 10) and then exposed to 0.3 % citric acid at pH 2.7 for 10, 20, 40 and 60 mins each followed by abrasion with non-fluoridated toothpaste for 240 strokes in a reciprocating brushing machine. A white light profilometer with a spot size of 12 um measured mean step-height following each cycle. Microhardness indentations were conducted following the final cycled 60 mins erosion/abrasion using 0.01, 0.02, 0.1, 0.5 and 2.5 kgf indentation load. Statistical disparity were evaluated using a two-way ANOVA and post-hoc Sidak's multiple comparisons tests at α = 0.05. RESULTS: After erosion/abrasion, the mean (SD) step-heights on occlusal and buccal surfaces were not significantly different until 60 mins, when occlusal surfaces exhibited greater step-heights, 32.9 µm (2.8) and 31.1 µm (1.8) and p = 0.02, respectively. Buccal and occlusal microhardness was statistically lower following erosion/abrasion at loads of 0.01 kgf (p = 0.0005) and 0.02 kgf (p = 0.0006) but no significant differences were observed in the microhardness between the surfaces at any loads. CONCLUSION: The occlusal and buccal surfaces were not statistically different for microhardness or step height suggesting the susceptibility to wear is not related to the anatomy and structure of the tooth and is more likely related to other factors such as the environment. CLINICAL SIGNIFICANCE: The study emphasizes that a notable difference in wear between occlusal and buccal enamel surfaces emerges only after prolonged exposure to simultaneous chemical and mechanical stress. This finding necessitates a preventive dental approach that accounts for both the duration of exposure and environmental factors.

Lesões cervicais não cariosas: considerações etiológicas, clínicas e terapêuticas / Lesiones cervicales no cariosas: consideraciones etiológicas, clínicas y terapéuticas / Non-carious cervical injuries: etiological, clinical and therapeutic considerations

RESUMO Introdução: As lesões cervicais não cariosas são lesões dentárias, que apresentam etiologia multifatorial, sem o envolvimento de bactérias. Objetivo: Descrever as características clínicas, etiologia e tratamento das lesões cervicais não-cariosas. Métodos: Realizou-se uma revisão bibliográfica de estudos publicados nos últimos 5 anos (2014-2018) por meio da busca nas bases de dados: PubMED/Medline, Lilacs, Science Direct, SciELO (Scientific Eletronic Library) e Google Acadêmico. Para a pesquisa foram utilizados os seguintes descritores: "lesões cervicais não cariosas (non-carious cervical lesions)", "abrasão dentária (dental abrasion)", "erosão dentária (dental erosion)", "abfração dentária (dental abfraction)" e "atrição dentária (dental atrittion). Após criteriosa filtragem, foram selecionados 26 artigos e 2 livros para inclusão no estudo. Análise e integração das informações: As lesões cervicais não cariosas comumente classificadas em: abrasão, abfração, erosão e atrição. Essas lesões podem apresentar diversas formas, apesar de serem incluídas em uma classe genérica de denominação. São lesões que causam a perda gradativa dos tecidos mineralizados dentários, podendo trazer inúmeras consequências ao dente acometido. Conclusão: Para um correto diagnóstico e decisão de tratamento, essas lesões devem ser vistas sob seu aspecto etiológico multifatorial. Diversas possibilidades terapêuticas podem ser utilizadas no tratamento dessas lesões sendo necessário que o clínico conheça os principais fatores etiológicos e características clínicas que as diferenciem(AU)

RESUMEN Introducción: Las lesiones cervicales no cariosas son lesiones dentales, que presentan etiología multifactorial, sin la participación de bacterias. Objetivo: Describir las características clínicas, etiología y tratamiento de las lesiones cervicales no cariosas. Métodos: Se realizó una revisión bibliográfica de estudios publicados en los últimos 5 años (2014-2018) a través de la búsqueda en las bases de datos: PubMED / Medline, Lilacs, Science Direct, SciELO (Scientific Eletronic Library) y Google Académico. Para la investigación se utilizaron los siguientes descriptores: "lesiones cervicales no cariosas", "abrasión dental", "erosión dental", "abfracción dental" y " " atrición dental. Después de un cuidadoso filtrado, se seleccionaron 26 artículos y 2 libros para su inclusión en el estudio. Análisis e integración de las informaciones: Las lesiones cervicales no cariosas comúnmente clasificadas en: abrasión, abfración, erosión y atrición. Estas lesiones pueden presentar diversas formas, aunque se incluyen en una clase genérica de denominación. Son lesiones que causan la pérdida gradual de los tejidos mineralizados dentales, pudiendo traer innumerables consecuencias al diente acometido. Conclusiones: Para un correcto diagnóstico y decisión de tratamiento, estas lesiones deben ser vistas bajo su aspecto etiológico multifactorial. Diversas posibilidades terapéuticas pueden ser utilizadas en el tratamiento de esas lesiones, por lo que resulta necesario que el clínico conozca los principales factores etiológicos y características clínicas que las diferencien(AU)

ABSTRACT Introduction: Non-carious cervical lesions are dental lesions of a multifactorial etiology, without the involvement of bacteria. Objective: Describe the clinical characteristics, etiology and treatment of non-carious cervical lesions Methods: A bibliographic review was conducted of studies published in the last five years (2014-2018) by searching the databases PubMED / Medline, Lilacs, Science Direct, SciELO (Scientific Electronic Library) and Google Scholar. The following descriptors were used: "non-carious cervical lesions", "dental abrasion", "dental erosion", "dental abfraction" and "dental attrition. After careful filtering, 26 articles and two books were selected for inclusion in the study. Data analysis and integration: Non-carious cervical lesions are commonly classified as abrasion, abfraction, erosion and attrition. These lesions may present various forms, but they are all grouped in a single generic class. They are lesions that cause the gradual loss of mineralized dental tissue, which may bring countless consequences to the affected tooth. Conclusions: For a correct diagnosis and treatment decision, these lesions must be seen under their multifactorial etiological aspect. Various therapeutic possibilities may be used in the treatment of these lesions, and it is necessary for the clinician to know the main etiological factors and clinical characteristics that differentiate them(AU)

Bruxismo y manifestaciones clínicas en el sistema estomatognático / Bruxism and clinical manifestations in the stomatognathic system

Fundamento: en tiempos actuales el bruxismo es un problema médico a escala mundial que involucra el apretamiento y rechinado de los dientes, diurno o nocturno, con distintos grados de intensidad y persistencia en el tiempo, de manera inconsciente.Objetivo: caracterizar el bruxismo y manifestaciones clínicas en el sistema estomatognático. Métodos: se realizó un estudio descriptivo trasversal en el consultorio No 14 de la clínica estomatológica Reynaldo Aday López del municipio Nuevitas de la provincia Camagüey, desde enero hasta julio de 2017, de un universo de 139 pacientes diagnosticados con bruxismo, se seleccionó una muestra no probabilística constituida por 67 pacientes. Resultados: predominó el sexo femenino y el grupo de edad entre 31 a 45 años. Se destacó el bruxismo tipo excéntrico respecto al céntrico. La principal manifestación clínica fueron las facetas de desgastes no funcionales en el 100 porciento de los pacientes examinados. Conclusiones: la caracterización de la población con bruxismo aportó datos de interés con mayor afectación en el sexo femenino, durante la tercera y cuarta década de vida, en los bruxópatas excéntricos, donde la totalidad de los pacientes presentaron facetas de desgaste no funcionales como principal manifestación clínica(AU)

Background: in current times bruxism is a medical problem on a world scale that involves clenching and grinding of the teeth, diurnal or nocturnal, with different degrees of intensity and persistence over time, unconsciously. Objective: to characterize bruxism and clinical manifestations in the stomatognathic system. Methods: a cross-sectional descriptive study was carried out in the clinic No 14 of Reynaldo Aday López stomatology clinic in the municipality of Nuevitas of Camagüey province, from January to July 2017, from a universe of 139 patients diagnosed with bruxism, a sample was selected not probabilistic constituted by 67 patients. Results: the female sex predominated and the age group between 31 to 45 years. The eccentric type bruxism was highlighted with respect to the centric one. The main clinical manifestation was the facets of non-functional wear in 100 percent of the patients examined. Conclusions: the characterization of the population with bruxism contributed data of interest with greater affectation in the female sex, during the third and fourth decade of life, in the eccentric bruxópatas, where all the patients presented nonfunctional wear facets as the main manifestation clinic(AU)

Lesiones cervicales no cariosas / Non-carious cervical lesions

El objetivo de este trabajo consiste en describir las distintas lesiones cervicales no cariosas, la abrasión, la erosión y la abfracción. Se desarrollarán en detalle su etiología, localización y características clínicas. Se mencionarán los diferentes procedimientos a realizar para su prevención y los materiales a utilizar para su restauración.

This article describes the different types of non-cariouscervical lesions, for example abrasion, erosionand abfraction. We will discuss their etiology, location and clinical features in detail. We will describe the procedures to prevent them, aswell as the materials used for their restoration.

Avaliação de lesões cervicais não-cariosas em adultos: estudo piloto / Evaluation of non-carious cervical lesions in adults: a pilot study

Objetivo: determinar as características clínicas e a prevalência de lesões cervicais não-cariosas (LCNCs) em pacientes adultos. Métodos: a coleta dos dados foi realizada por meio de exame clínico e questionário. Um total de 491 dentes foi avaliado em 23 pacientes, dos quais 121 dentes apresentavam LCNCs. Critérios como forma, dimensão horizontal e vertical, profundidade, término, classificação e sensibilidade dentinária das lesões, além dos fatores oclusais fizeram parte da avaliação. Os dados foram submetidos à análise estatística pelo teste não paramétrico Exato de Fischer, com nível de significância de 5%. Uma análise descritiva foi utilizada para dados que caracterizavam a amostra no nível do indivíduo (sexo e fatores etiológicos das LCNCs) e no nível do dente (presença, tipo e formato da lesão; dentes e faces mais comprometidos). Resultados: um total de 24,64% dos dentes apresentava algum tipo de lesão cervical, sendo os dentes pré-molares inferiores os mais acometidos (30,58%). A abfração foi a lesão mais presente (52,89%). A face vestibular foi mais comprometida pelas LCNCs com significância estatística (p = 0,013). As cavidades rasas foram mais prevalentes em todos os tipos de lesões (p = 0,001). Facetas de desgaste foram bastante encontradas nos dentes com LCNCs (p = 0,008). A sensibilidade dentinária severa foi mais observada em dentes com abrasão (p=0,037). Conclusão: dentre as LCNCs, as lesões de abfração foram mais encontradas em pessoas do sexo feminino, nas faces vestibulares de dentes pré-molares e com profundidade rasa...

Objective: To determine the clinical characteristics and prevalence ofnon-carious cervical lesions (NCCL) in adult patients. Method: Data were collected by clinical examination and questionnaire-based interviews. A total of 491 teeth from 23 patients were examined, resulting in a sample of 121 teeth with NCCL. The evaluation criteria included shape, horizontal and vertical dimensions, depth, cervical margin, classification, presence of dentinal hypersensitivity and occlusal factors. The data were subjected to statistical analysis by the non-parametric Fisher?s exact test at a 5% significance level. Descriptive analysis was used for the data that characterized the sample at individual level (gender and NCCL etiologic factors) and tooth level (presence, type and shape of the lesion, and the most affected teeth and surfaces). Results: As much as 24.64% of the teeth presented some kind of cervical lesion, the mandibular premolars being the most affected (30.58%). Abfraction was the prevalent type of lesion (52.89%). The buccal surface was the most affected by NCCL (p=0.013). Shallow cavities were the most prevailing lesion type (p=0.001). Wear facets were largely found in teeth with NCCL (p=0.008). Severe dentinal hypersensitivity was mainly observed in abraded teeth (0.037).Conclusion: Among the types of NCCL, abfraction lesions were mostly found in female patients, in the buccal surface of premolars and had shallow depth...

Desgaste abrasivo de uma resina composta, através de três diferentes métodos (disco retificado, escovação e nanodurômetro) / Abrasive wear of a composite resin, using three different methods (ground disc, toothbrushing and nanodurometer)

Neste estudo, foi avaliada a resistência ao desgaste abrasivo de uma resina composta, através de três diferentes métodos: do disco retificado, por escovação e do nanodurômetro. Nos dois primeiros métodos, foram utilizados 20 espécimes da resina Filtek Z250 (10 da cor Incisal e 10 da cor C4, ambos fotopolimerizados por 30 segundos cada) e 10 de polimetilmetacrilato (PMMA), atuando estes últimos como padrão de referência. Para os ensaios com o nanodurômetro, foi utilizado apenas um espécime de cada cor, assim como um único de PMMA, em cujas superfícies planas foram efetuadas sete medições, o que foi considerado equivalente a sete espécimes. No método do disco retificado, cada espécime de resina composta era confeccionado diretamente numa cavidade semicircular, localizada na periferia de um disco-suporte; os espécimes de PMMA consistiam em discos constituídos exclusivamente por este material; o desgaste de cada espécime era promovido por um disco de porcelana e seu conseqüente deslocamento era detectado por um palpador; assim, a taxa de desgaste era estabelecida, expressa em milímetros cúbicos por newton por segundo (mm3/N.s). No método de escovação, cada espécime cilíndrico ficava preso numa placa metálica, a qual era fixada no interior da máquina de escovação; sua perda de massa (em miligramas) era verificada através de uma balança analítica. No método do nanodurômetro, existiu apenas um espécime ci líndrico para cada condição, em cuja face plana superior eram feitos sete sulcos (equivalentes a sete espécimes); o coeficiente de atrito permitia estabelecer a respectiva resistência ao desgaste. Para cada método utilizado, os dados foram tratados estatisticamente, através de análise de variância (ANOVA) e de teste de Tukey. Pôde-se concluir que, através do disco retificado, a taxa de desgaste (em mm3/N.s) dos materiais foi: Incisal (0,6807) > C4 (0,5012) > PMMA (0,1439); que, através da escovação, a taxa de desgaste (em mg) foi de 5,40 para...

Abrasive wear of a composite resin, using three different methods (ground disc, toothbrushing and nanodurometer). The aim at this study was to evaluate the resistance to abrasive wear of a composite resin, using three different methods: ground disc, toothbrushing and nanodurometer. At the first two methods were employed 20 specimens of Filtek Z250 composite resin (10 of Incisal and 10 of C4, both the colors cured for 30 seconds each one) and 10 of polymethylmethacrylate (PMMA), the latter acting as a reference standard. For the tests with the nanodurometer it was used only one specimen of each color, as well as just one of PMMA, in whose flat surfaces seven measurements were made, what was considered equivalent to seven specimens. At the ground disc method, each composite resin specimen was directly made on a semicircular cavity located on the periphery of a supporting disc; PMMA specimens consisted of discs made up exclusively with this material; the wear of each specimen was promoted by a ceramic disc and its consequent displacement was detected by a sensor; thus, the wear rate was established, expressed in cubic millimeters per newton per second (mm3/N.s). At the toothbrushing method, each cylindrical specimen was trapped in a metal plate, which was fixed inside the machine brushing; its weight loss (in milligrams) was verified by an analytical balance. At the nanodurometer method, there was only one cylindrical specimen for each condition, in whose flat upper face seven grooves were made (what was equivalent to seven specimens); the coefficient of friction was used to establish its wear resistance. For each method, data were statistically analyzed by ANOVA and Tukey's test. It could be concluded that, by ground disc method, materials wear rate (in mm3/N.s) was Incisal (0.6807) > C4 (0.5012) > PMMA (0.1439); by brushing method, materials wear rate (in mg) was 5.40 for Incisal, 9.35 for C4 and 5.88 for PMMA, without significant difference...

Tomada de decisão para as lesões cervicais não-cariosas por cirurgiões-dentistas da cidade de São Miguel do Oeste-SC / Decision making for non-carious cervical lesions by dentists in the city of São Miguel do Oeste-SC

O presente estudo avaliou a tomada de decisão dos cirurgiões-dentistas da cidade de São Miguel do Oeste, Santa Catarina, em relação à classificação, etiologia e o tratamento das lesões cervicais não-cariosas. A pesquisa foi descritiva e utilizou como instrumento de pesquisa questionários com perguntas a respeito de duas imagens clínicas de lesões cervicais não-cariosas. A amostra contou com 31 cirurgiões-dentistas sócios da Associação Brasileira de Odontologia de Santa Catarina. Os resultados mostraram que a maioria dos cirurgiões-dentistas classificou a lesão da primeira figura como abrasão (54,8%), sendo a sua principal etiologia a escovação dentária (87,1%) e o tratamento escolhido foi a proservação com aplicações tópicas de flúor e desensibilizantes (90,3%). A segunda figura foi classificada como abfração (67,7%), sendo as forças oclusais a sua principal etiologia (41,9%), seguida pela escovação dentária (38,7%) e o tratamento de escolha foi restaurador (87,1%). Verificou-se que apesar da dificuldade na determinação do diagnóstico, das causas e do tratamento desse tipo de lesão, a maioria dos profissionais tomou decisões semelhantes frente às lesões cervicais não-cariosas.

The present study has evaluated the decision making of the dentists acting in São Miguel do Oeste, Santa Catarina, related to the classification, etiology and treatment of non-carious cervical lesions. The study was descriptive and used as research instrument, questionnaires with questions about two clinical images of non-carious cervical lesions. The sample was composed of 31 dentists, all belonging to the Association of Brazilian Dentists of the state of Santa Catarina. The results show that most dentists classified the first picture lesion as abrasion (54.8%). The toothbrushing of the teeth was the preferred etiology (87.1%) and the chosen treatment was follow up with topical fluoride and desensibilizing agents (90.3%). The second picture was classified as abfraction (67.7%) and the occlusal forces were the main etiology (41.9%), followed by toothbrushing (38.7%) and the treatment of choice was the restoration (87.1%). It was concluded that in spite of the difficulty in determining the diagnosis, the etiology and treatment of this type of injury, most professionals decision maked cervical lesions similar.

Resistencia al desgaste de materiales estéticos para la restauración de lesiones cervicales / Wear resistance of esthetic materials for the restoration of cervical lesions

El objetivo del presente trabajo fue evaluar la resistencia al desgaste de seis materiales restauradoresestéticos, utilizando como abrasivo una pasta dentífrica a base de bicarbonato de sodio y un dispositivo ad hoc con cepillos dentales, simulando una situación clínica, para considerar su utilización en restauraciones de lesiones cervicales por abrasión. Se confeccionaron 10 probetas (n =60) de cada material, quedando conformados los siguientes grupos: F (F2000/3M ESPE); A (A110/3M ESPE); DY (Dyract Flow/Dentsply); T (Tetric Ceram/Vivadent); PH (Photac Fil/ 3M ESPE) y PF (Perma Flo/Ultradent). Se registró la masa inicial para cada espécimen (PI) previamente al ensayo experimental; posteriormente las probetas fueron pesadas nuevamente para determinar la masa final (PF) a los 7, 30 y 60 días. De la diferencia entre los valores registrados (PI/PF), en losdiferentes períodos de tiempo, se dedujo la pérdida total de masa para cada material. El mayor desgaste lo presentó el ionómero vítreo híbrido con diferencias significativas con respecto a los otros materiales y sólo a los siete días.

Resistencia al desgaste de materiales estéticos para la restauración de lesiones cervicales / Wear resistance of esthetic materials for the restoration of cervical lesions

El objetivo del presente trabajo fue evaluar la resistencia al desgaste de seis materiales restauradoresestéticos, utilizando como abrasivo una pasta dentífrica a base de bicarbonato de sodio y un dispositivo ad hoc con cepillos dentales, simulando una situación clínica, para considerar su utilización en restauraciones de lesiones cervicales por abrasión. Se confeccionaron 10 probetas (n =60) de cada material, quedando conformados los siguientes grupos: F (F2000/3M ESPE); A (A110/3M ESPE); DY (Dyract Flow/Dentsply); T (Tetric Ceram/Vivadent); PH (Photac Fil/ 3M ESPE) y PF (Perma Flo/Ultradent). Se registró la masa inicial para cada espécimen (PI) previamente al ensayo experimental; posteriormente las probetas fueron pesadas nuevamente para determinar la masa final (PF) a los 7, 30 y 60 días. De la diferencia entre los valores registrados (PI/PF), en losdiferentes períodos de tiempo, se dedujo la pérdida total de masa para cada material. El mayor desgaste lo presentó el ionómero vítreo híbrido con diferencias significativas con respecto a los otros materiales y sólo a los siete días.(AU)

Avaliação do desgaste por escovação, in vitro, de uma resina composta, fotopolimerizada por lâmpada halógena, em dois diferentes tempos / In vitro toothbrushing wear evaluation of a resin composite cured by QTH curing unit in two different times

Um dos principais problemas dos materiais restauradores (incluindo a resina composta) é o desgaste por abrasão. Portanto, o objetivo neste trabalho foi avaliar in vitro o desgaste abrasivo por escovação da resina composta 4Seasons, de duas cores diferentes (A3 e C4) e com fotopolimerização por dois diferentes tempos (20 e 40 s), utilizando escova Sorriso, da Colgate, e creme dentifrício Colgate Tripla Ação; também foi usado, como material de referência, o polimetil metacrilato. Assim, foram confeccionados dez corpos-de-prova, para cada um dos cinco grupos formados (PMMA, A3 20s, A3 40s, C4 20s, C4 40s). Cada espécime consistia basicamente num cilindro de cerca de 1,8 mm de altura e 8 mm de diâmetro. Cada espécime, após sua confecção, era imerso em água deionizada, a 37 ± 2 ºC, por 24 horas, quando então eram regularizados com lixa (granulação # 600 e # 1.000); após lavagem com ultrassom, voltavam a ser armazenados nas mesmas condições, até completar-se um período de uma semana. A escovação foi então efetuada numa máquina própria, que comportava dez espécimes simultaneamente, sendo de 3 N a carga de cada escova sobre o respectivo espécime; a velocidade de cada escova era de 18 cm/s, com a freqüência (ida e volta, num percurso total de 4 cm) de 4,5 ciclos/s; o período de escovação de um espécime compreendia 150. 000 ciclos. Foram efetuados cinco períodos (ou lotes) de escovação, de modo que um espécime do material de cada grupo tivesse sido submetido à ação de cada uma das posições ocupadas pelas dez escovas.

A quantidade de massa perdida, para cada espécime, foi calculada por meio de pesagem (pré e pós escovação), numa balança com acuidade de milionésimo de grama. O trabalho foi também ilustrado com gráficos de rugosidade e com fotomicrografias tomadas ao MEV. A taxa média de desgaste foi de 2,8 mg para o PMMA, de 5,5 mg para o A3-20s, 4,7 mg para o A3-40 s, 5,4 para o C4-20s e 4,2 mg para o C4-40s; a respectiva análise de variância mostrou não existir diferença significante entre os grupos, para p=0,166; o coeficiente de variação entre os grupos foi bastante semelhante. Foi possível concluir que não existiu diferença da resistência ao desgaste abrasivo entre os grupos estudados.

One of the main problems of dental restorative materials (including the resin composites) is the abrasion wear. Therefore, the aim of this work was to evaluate in vitro the abrasive wear by toothbrushing of the resin composite 4Seasons, of two different colors (A3 and C4), cured by two different times (20 and 40 s), using a toothbrush (Sorriso - Colgate), and a dentifrice (Tripla Ação Colgate). Polimetil meth-acrylate was used as reference material. Ten cylindric samples (approximately 1.8 mm height and 8 mm diameter) had been prepared for each one of the five evaluated groups (PMMA, A3 20s, A3 40s, C4 20s, C4 40s). After confection, samples were immersed in deionized water, at 37 ± 2ºC, for 24 h, and then regularized by abrasive gritting with sandpaper (from #600 to # 1 000); after that, were cleaned in ultrasound bath, and restored to the same described conditions, until completing the period of one week. The toothbrushing was then conducted in a proper machine that holds 10 specimens simultaneously, with a 3 N load of each toothbrush on the respective sample. The speed of each toothbrush was of 18 cm/s, at a frequency of 4.5 cycles/s (each cycle consisting of 2 cm forward and 2 cm backward). 150. 000 cycles were applied per sample. Five periods (or lots) of toothbrushing had been performed, in a way that one sample of each group had been submitted to the brushing action at one position in the machine.

The amount of weight loss for each sample was calculated by means of weighting (before and after toothbrushing), in an analytical balance with accuracy of millionth of gram. Roughness and MEV photomicrographies were also evaluated. The average rate of wear was of 2.8 mg for PMMA, 5.5 mg for A3-20s, 4.7 mg for A3-40 s, 5.4 for C4-20s, and 4,2 mg for C4-40s. One-way ANOVA showed no significant difference between groups (p = 0.166). The coefficient of variation between the groups was sufficiently similar. It was possible to conclude that difference of the resistance to the abrasive wear between the studied groups did not exist.

Assessment in vitro of brushing on dental surface roughness alteration by laser interferometry

Noncarious cervical lesions (NCCLs) are considered to be of multifactorial origin, normally associated with inadequate brushing. This study assessed the influence in vitro of simulated brushing on NCCL formation. Fifteen human premolars were submitted to brushing in the cementoenamel junction region, using hard-, medium- and soft-bristled brushes associated with a toothpaste of medium abrasiveness under a 200 g load, at a speed of 356 rpm for 100 minutes. The surface topography of the region was analyzed before and after brushing, by means of a laser interferometer, using "cut-off" values of 0.25 and considering roughness values in mm. The initial roughness (mm) results for dentin (D / bristle consistency: 1 - soft, 2 - medium and 3 - hard) were as follows: (D1) 1.25 ± 0.45; (D2) 1.12 ± 0.44; (D3) 1.05 ± 0.41. For enamel (E / bristle consistency: 1 - soft, 2 - medium and 3 - hard), the initial results were: (E1) 1.18 ± 0.35; (E2) 1.32 ± 0.25; (E3) 1.50 ± 0.38. After brushing, the following were the values for dentin: (D1) 2.32 ± 1.99; (D2) 3.30 ± 0.96; (D3) Over 500. For enamel, the values after brushing were: (E1) 1.37 ± 0.31; (E2) 2.15 ± 0.90; (E3) 1.22 ± 0.47. Based on the results of the ANOVA and Tukey statistical analyses (a = .05) it was concluded that soft, medium and hard brushes are not capable of abrading enamel, whereas dentin showed changes in surface roughness by the action of medium- and hard-bristled brushes.

In vitro toothbrushing abrasion of dental resin composites: packable, microhybrid, nanohybrid and microfilled materials

This study evaluated weight loss and surface roughening after toothbrushing of different resin composites: one packable (Solitaire 2, Heraeus Kulzer), one microhybrid (Charisma, Heraeus Kulzer), one nanohybrid (Simile, Pentron) and one microfilled (Durafill VS, Heraeus Kulzer). Cylindrical specimens (n = 20) were prepared. Half of the samples were submitted to 60,000 strokes, at 4 Hz, with a dentifrice-water slurry. Control samples (n = 10) remained stored at 37°C. Pre- and post-abrasion parameters for weight (mg) and surface roughness (Ra, µm) were determined on an analytical balance and a surface profilometer. Data were separately submitted to Repeated Measures ANOVA and Tukey's test (a = 0.05). Percentages of weight loss were analyzed by ANOVA and Tukey's test (a = 0.05). The relationship between both evaluations was assessed by Pearson's test (a = 0.05). The means ( percent) for weight loss (standard deviation) were 0.65(0.2), 0.93(0.2), 1.25(0.6) and 1.25(0.4) for Simile, Durafill, Charisma and Solitaire, respectively. Baseline roughness means ranged from 0.065(0.01), 0.071(0.01), 0.066(0.02) and 0.074(0.01) for Simile, Durafill, Charisma and Solitaire, respectively, to 0.105(0.04), 0.117(0.03), 0.161(0.03) and 0.214(0.07) after testing. The composites with larger fillers presented higher weight loss and roughening than the finer materials (p < 0.05). For both evaluations, control specimens showed no significant alteration. No significant relationship between loss of weight and roughness alteration was detected (r = 0.322, p = 0.429).

Scanning electron microscopic study of the in situ effect of salivary stimulation on erosion and abrasion in human and bovine enamel

This in situ study investigated, using scanning electron microscopy, the effect of stimulated saliva on the enamel surface of bovine and human substrates submitted to erosion followed by brushing abrasion immediately or after one hour. During 2 experimental 7-day crossover phases, 9 previously selected volunteers wore intraoral palatal devices, with 12 enamel specimens (6 human and 6 bovine). In the first phase, the volunteers immersed the device for 5 minutes in 150 ml of a cola drink, 4 times a day (8h00, 12h00, 16h00 and 20h00). Immediately after the immersions, no treatment was performed in 4 specimens (ERO), 4 other specimens were immediately brushed (0 min) using a fluoride dentifrice and the device was replaced into the mouth. After 60 min, the other 4 specimens were brushed. In the second phase, the procedures were repeated but, after the immersions, the volunteers stimulated the salivary flow rate by chewing a sugar-free gum for 30 min. Enamel superficial alterations of all specimens were then evaluated using a scanning electron microscope. Enamel prism core dissolution was seen on the surfaces submitted to erosion, while on those submitted to erosion and to abrasion (both at 0 and 60 min) a more homogeneous enamel surface was observed, probably due to the removal of the altered superficial prism layer. For all the other variables - enamel substrate and salivary stimulation -, the microscopic pattern of the enamel specimens was similar.