Comparison of in vitro erosion protocols in bovine teeth to simulate natural erosion lesion: analysis of mechanical properties and surface gloss

Objective: The aim of this study was to compare two in vitro erosion protocols, in which one simulates in vivo conditions experienced by patients with gastroesophageal disorders or bulimia (HCl-pepsin protocol), and the other simulates the diet of an individual who consumes a high volume of erosive beverages (citric acid protocol). In addition, the mechanical properties and surface gloss of eroded human dentin were compared with those of sound human dentin. Materials and Methods: Blocks of cervical dentin were used: sound human dentin (n=10), human dentin with erosive lesions (n=10), and bovine dentin (n=30). Twenty bovine blocks were subjected to either of two erosion protocols (n=10/protocol). In the first protocol, samples were demineralized using HCl-pepsin solution, then treated with trypsin solution. In the second protocol, samples were demineralized with 2% citric acid. Toothbrushing was performed in both protocols using a toothbrushing machine (15 s with a 150 g load). Ten bovine dentin blocks were not subjected to any erosive treatment. All samples of bovine and human dentin were analyzed to obtain Martens hardness values (MH), elastic modulus (Eit*) and surface gloss. One-way ANOVA and Tukey’s test were performed to analyze the data (α=0.05). Results: Sound human and eroded human dentin groups showed similar MH and Eit* values (p>0.05); however, sound human dentin showed a higher surface gloss value when compared to eroded human dentin (p<0.05). Sound bovine dentin and HCl-pepsin-treated bovine dentin treatments resulted in similar values for both MH and Eit* (p>0.05), but HClpepsin-treated bovine dentin and citric acid-treated bovine dentin resulted in lower surface gloss than sound bovine dentin (p<0.05). Conclusions: The HCl-pepsin protocol modified bovine dentin properties that could be similar to those that occur on human dentin surfaces with erosive lesions

Microabrasion in tooth enamel discoloration defects: three cases with long-term follow-ups

Superficial irregularities and certain intrinsic stains on the dental enamel surfaces can be resolved by enamel microabrasion, however, treatment for such defects need to be confined to the outermost regions of the enamel surface. Dental bleaching and resin-based composite repair are also often useful for certain situations for tooth color corrections. This article presented and discussed the indications and limitations of enamel microabrasion treatment. Three case reports treated by enamel microabrasion were also presented after 11, 20 and 23 years of follow-ups224347354sem informaçã

Microabrasion in tooth enamel discoloration defects: three cases with long-term follow-ups

Superficial irregularities and certain intrinsic stains on the dental enamel surfaces can be resolved by enamel microabrasion, however, treatment for such defects need to be confined to the outermost regions of the enamel surface. Dental bleaching and resin-based composite repair are also often useful for certain situations for tooth color corrections. This article presented and discussed the indications and limitations of enamel microabrasion treatment. Three case reports treated by enamel microabrasion were also presented after 11, 20 and 23 years of follow-ups

Transferring ART research into education in Brazil

The aim of this study was to evaluate the teaching of the Atraumatic Restorative Treatment (ART) approach in Brazilian dental schools. MATERIALS AND METHODS: A questionnaire on this subject was sent to Pediatric Dentistry, Operative Dentistry and Public Health Dentistry professors. The questions approached the followig subjects: the method used to teach ART, the time spent on its teaching, under which discipline it is taught, for how many years ART has been taught and its effect on the DMFT index. RESULTS: A total of 70 out of 202 dental schools returned the questionnaire. The ART approach is taught in the majority of the Brazilian dental schools (96.3%), and in most of these schools it is taught both in theory and in clinical practice (62.9%). The majority (35.3%) of professors teach ART for 8 hours, and most often as part of the Pediatric Dentistry discipline (67.6%). It has been taught for the last 7 to 10 years in 34.3% of dental schools. Most professors did not observe a change in the DMFT index with this approach. There is a diversity in the teaching of ART in Brazil in terms of the number of hours spent, the teaching method (theory and practice), and the disciplines involved in its teaching. CONCLUSIONS: It is necessary to address the training of professors in the ART approach for the whole country. An educational model is proposed whereby a standard ART module features as part of other preventive and restorative caries care educational modules. This will facilitate and standardize the introduction and adoption of the ART approach in undergraduate education in Brazil

Influence of ultrasonic setting on compressive and diametral tensile strengths of glass ionomer cements

The aim of this study was to assess the influence of ultrasonic wave propagation on the compressive (CS) and diametral tensile (DTS) strengths of glass ionomer cements (GICs). Three variables were evaluated: conventional GICs, ultrasonic excitation and storage time (1 hour, 24 hours and 7 days). Bovine teeth molds were used for simulating a clinical ultrasonic excitation. The data were submitted to three-way ANOVA and Tukey tests (P < 0.05). All the tested conventional GICs presented an increase in strength from 1 hour to 7 days for CS and DTS. Ultrasonic excitation resulted in a statistically significant increase in the CS, but showed no statistically significant difference in the DTS. Regardless the GICs tested the increase in strength was maturation time-dependent for all groups

Resistência à compressão e à tração diametral de cimentos de ionômero de vidro

The aim of this study was to compare, in different periods of time, the compressive and diametral tensile strength of a traditional high viscous glass ionomer cement: Fuji IX (GC Corporation), with two new Brazilian GIC's: Vitro-Molar (DFL) and Bioglass R (Biodinamica), all indicated for the Atraumatic Restorative Treatment (ART) technique. Fifteen disk specimens (6.0mm diameter x 3.0mm height) for the diametral tensile strength (DTS) test and fifteen cylindrical specimens (6.0mm diameter x 12.0mm height) for the compressive strength (CS) test were made of each GIC. Specimens were stored in deionized water at 37&ordm; C and 100% of humidity in a stove until testing. Five specimens of each GIC were submitted to CS and DTS test in each period, namely 1 hour, 24 hours and 7 days. The specimens were tested in a testing machine (Emic) at a crosshead speed of 1.0mm/min for CS and 0.5mm/min for the DTS test until failure occurred. The data were submitted to two-way ANOVA and Tukey tests (alpha=0.05). The mean CS values ranged from 42.03 to 155.47MPa and means DTS from 5.54 to 13.72 MPa, with test periods from 1h to 7 days. The CS and DTS tests showed no statistically significant difference between Fuji IX and Vitro Molar, except for CS test at 1-hour period. Bioglass R had lowest mean value for CS of the cements tested. In DTS test Bioglass R presented no statistically significant differences when compared with all others tested GICs at 1-hour period and Bioglass R presented no difference at 24-hour and 7-day periods when compared to Vitro-Molar. Further studies to investigate other physical properties such as fracture toughness and wear resistance, as well as chemical composition and biocompatibility, are now needed to better understand the properties of these new Brazilian GIC's.Comparou-se a Resistência à Compressão (RC) e à Tração Diametral (TD) de um cimento de ionômero de vidro de alta viscosidade [Fuji IX (GC Corporation)] e de dois novos cimentos Brasileiros [Vitro Molar (DFL) e Bioglass R (Biodinamica)], recentemente lançados no mercado, ambos indicados para o Tratamento Restaurador Atraumático (ART), em diferentes períodos de tempo. Foram confeccionados quinze corpos-de-prova com 6,0 mm de diâmetro x 3,0 mm de altura para o teste de TD e quinze com 6,0 mm de diâmetro e 12,0 mm de altura para o teste de RC, para cada ionômero a ser testado. Os corpos-de-prova foram armazenados em recipientes plásticos, com água deionizada, e mantidos em estufa a 37&ordm;C e 100% de umidade, até a realização dos testes. Cinco corpos-de-prova de cada material foram submetidos aos testes de TD e RC em cada período de tempo: 1-hora, 24-horas e 7-dias, em uma máquina de testes universal (EMIC - DL 500) a uma velocidade de 1,0 mm/min para RC e 0,5mm/min para TD. Os dados obtidos foram submetidos aos testes ANOVA a dois critérios e Tukey (á=0,05). Os valores médios de RC e TD variaram de 42,03 a 155.47 MPa e de 5,54 a 13,72 MPa, respectivamente para os períodos analisados. O Fuji IX e o Vitro Molar não apresentaram diferenças em relação aos testes de RC e TD, exceto para RC no período de 1-hora. O Bioglass R apresentou os menores valores de RC dos cimentos testados. Na TD o Bioglass R não apresentou diferença em relação aos outros cimentos testados no período de 1-hora e não foi diferente do Vitro-Molar nos períodos de 24-horas e 7-dias. Mais estudos são necessários para avaliar outras propriedades mecânicas desses novos cimentos de ionômero de vidro brasileiros, tais como: tenacidade e desgaste, bem como composição química e biocompatibilidade

Reparo de resinas compostas envelhecidas e mediadas por diferentes materiais restauradores

The aim of this study was to evaluate the shear bond strength of resin composite repairs with and without aging of the surface to be repaired, using different adhesive systems and resin composites. Ninety specimens were prepared: 10 for the Control Group (GC - without repair); 40 for Group I (GI - repairs after 7 days) and 40 for Group II (GII - repairs after 180 days). Groups I and II were divided into 4 subgroups of 10 specimens each, according to the adhesive system and composite resin used: A) Adper Scotch Bond Multipurpose + Filtek Z350 XT; B) Adper Single Bond Plus + Filtek Z350 XT; C) Adper Scotch Bond Multipurpose + Esthet-X; D) Adper Single Bond Plus + Esthet-X. The specimens were tested for shear strength in a universal testing machine. The results were analyzed by two-factor one-way ANOVA and Fisher’s post hoc tests (alpha=0.05). The control group had better performance than the other groups. There was no significant difference when comparing different adhesive systems and composite resins. Repairs performed at 7 days were better than those performed at 180 days. The composite repairs decreased the mechanical strength of the restoration. Aging of the resin substrate may decrease repair bond strength over time, regardless of the type of adhesive systems and resin composites used.Avaliar a resistência de união ao cisalhamento de reparos de resina composta com e sem envelhecimento da superfície a ser reparada, utilizando diferentes sistemas adesivos. Noventa corpos de prova foram confeccionados sendo: 10 para o Grupo Controle (GC - sem reparo); 40 para o Grupo I (GI - reparos após 7 dias) e 40 para o Grupo II (GII – reparos após 180 dias). Para os reparos, os grupos GI e GII foram subdivididos em 4 subgrupos com 10 corpos de prova, variando o sistema adesivo e a resina composta: A) Adper Scotch Bond Multipurpose+ Filtek Z350XT; B)Adper Single Bond Plus+ Filtek Z350XT; C)Adper Scotch Bond Multipurpose+ Esthet-X; D) Adper Single Bond Plus+ Esthet-X. Os corpos de prova foram submetidos a uma força de cisalhamento em uma máquina de ensaio universal (EMIC). Os resultados foram analisados pelo teste estatístico Anova dois fatores, seguido pelo teste de Fisher´s. Observou-se melhor comportamento do grupo controle sobre os demais grupos, além disso, os reparos realizados aos 7 dias foram superiores aos dos realizados em 180 dias. Não houve diferença significativaquando se comparou diferentes sistemas adesivos e resinas compostas. Os reparos de resina composta diminuem a resistência mecânica da restauração.O envelheci mento do substrato de resina pode diminuir a resistência ao reparo ao longo do tempo, independentemente do tipo de sistemas adesivos e resinas compostas utilizados

Influence of daily usage times on patients’ compliance during at-home bleaching : a randomized clinical trial

The effectiveness of at-home dental bleaching treatments depends on the time that bleaching products are in contact with the teeth surface and, consequently, on the adequate use of associated custom acetate trays. Objective: This randomized single-blinded trial aimed to analyze if the daily usage time of these products influences the patient’s compliance behavior when submitted to monitored at-home dental bleaching. Secondary outcomes were color change and tooth sensitivity. Methodology: Sixty-six volunteers were randomly distributed into three groups (n=22): patients were instructed to use the trays for 2 (G2), 4 (G4), and 8 (G8) hours daily. The daily dental bleaching compliance behavior was measured using a microsensor inserted into the trays. Subjective and objective color evaluation assessments were adopted at baseline (T0), one (T1), two (T2), and three weeks (T3) after the beginning of the bleaching treatment, as well as two weeks after the treatment (T4). Tooth sensitivity was analyzed using the VAS scale, ranging from T1 to T4. Results: G2 showed a greater degree of cooperation than G8 and cooperation was inversely proportional to the recommended usage time. Significantly higher color change was observed in the upper arch for G8 when compared to G2 in subjective analysis, from T1 to T4. There were no statistical differences between the groups in objective analysis. Conclusion: Shorter recommended usage time of the bleaching product may improve the patient's compliance with at-home dental bleaching treatments. However, increased daily usage time may promote better subjective color change. Bleaching sensitivity was more significant in the first week for a longer time of use

Effects of different toothpastes on the prevention of erosion in composite resin and glass ionomer cement enamel and dentin restorations

Objective:This study aimed to evaluate the effects of different toothpastes on the surface wear of enamel, dentin, composite resin (CR), and resin-modified glass ionomer cement (RMGIC), and to perform a topographic analysis of the surfaces, based on representative images generated by atomic force microscopy (AFM) after erosion-abrasion cycles. Methodology: One hundred and forty bovine incisors were collected and divided into two groups: 72 enamel and 72 dentin blocks (4×4 mm). Half of the specimens were restored with CR (Filtek Z350 XT) and the other half with RMGIC (Fuji II LC). Then, samples were submitted to a demineralization cycle (5 days, 4×2 min/day, 1% citric acid, pH 3.2) and exposed to three different toothpastes (2×15 s/day): without fluoride (WF, n=12), sodium fluoride-based (NaF, n=12), and stannous fluoride-based (SnF2, n=12). Surface wear, as well as restoration interfaces wear, were investigated by profilometry of the dental substrates and restorative materials. All representative surfaces underwent AFM analysis. Data were analyzed by two-way analysis of variance and Tukey’s tests (α=0.05). Results: NaF-based toothpaste caused the greater dentin surface wear (p&lt;0.05). Toothpastes affected only enamel-restoration interfaces. AFM analysis showed precipitate formation in dentinal tubules caused by the use of fluoride toothpastes. Conclusions: NaF-based toothpastes had no protective effect on enamel adjacent to CR and RMGIC against erosion-abrasion challenges, nor on dentin adjacent to RMGIC material. SnF2-based toothpastes caused more damage to interfaces between enamel and RMGIC

Effect of different conditions and modes of application on bond strength of adhesives to dentine

Objetivo: Evaluar la resistencia de la unión microtensil en diferentes condiciones de dentina (grabado-E, sin&nbsp;grabado-N, seco-D y húmedo-W) de un adhesivo multimodo (Scotchbond Universal-SU, 3M/ESPE) y un adhesivo de grabado total (Ambar-AB, FGM) utilizando un dispositivo sónico (Smart Sonic Device-SD, FGM). Material&nbsp;y Métodos: En este estudio in vitro, noventa y seis molares humanos extraídos sanos se dividieron en 12 grupos&nbsp;(n=8) de acuerdo con diferentes condiciones de dentina y sistemas adhesivos. Se eliminó el esmalte y se pulieron&nbsp;las superficies centrales de la dentina. Cada sistema adhesivo se aplicó de acuerdo con las diferentes condiciones&nbsp;de dentina, y los bloques de resina compuesta se acumularon de forma incremental y se almacenaron durante 24h.&nbsp;Las muestras se seccionaron en barras y los datos de resistencia de la unión se analizaron con la prueba de Kruskal-Wallis y la prueba de U de Mann-Whitney. Resultado: No se observaron efectos de la aplicación sónica. En general,&nbsp;AB mostró resultados más bajos en comparación con el SU. Las condiciones E y N no afectaron estadísticamente&nbsp;la fuerza de unión de los grupos SU. La dentina seca presentó valores de fuerza de adhesión estadísticamente&nbsp;superiores en comparación con la dentina húmeda para el grupo SU/E/SD. Conclusión: La adhesión de la dentina&nbsp;seca con un sistema adhesivo multimodo puede ser superior a la dentina húmeda con aplicación sónica. Los modos&nbsp;de aplicación no tuvieron influencia en la resistencia de la unión de los adhesivos estudiados