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

Abstract 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<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.

How does the quarantine resulting from COVID-19 impact dental appointments and patient anxiety levels?

Abstract The present study sought to evaluate the impact of quarantine resulting from the coronavirus disease 2019 (COVID-19) pandemic on dental appointments and patients' positions and concerns regarding their ongoing dental treatment. Patients from private dental clinics answered an online questionnaire anonymously regarding their treatment, availability and willingness to attend dental appointments, and concerns about contamination. Descriptive statistics of the responses were performed with percentages and responses were compared between sexes, regions, and other aspects using the chi-squared test. Five hundred ninety-five patients (412 females and 183 males; mean age: 38.21 years) answered the questionnaire. Most patients reported they were receiving dental treatment (orthodontics) and would attend to a dental appointment; meanwhile, those patients not receiving treatment would not attend or would visit only in the case of an emergency. Males reported to be calmer than females, who were more anxious and afraid; as such, males reported more willing to go a dental appointment while, in general, females were not worried about how quarantine could affect dental treatment. Patients actively undergoing treatment and orthodontic patients were more concerned about a delay in treatment. There was a significant association between feelings about the COVID-19 pandemic and the level of willingness to attend a dental appointment. The quarantine recommended due to the COVID-19 pandemic was shown to have an impact on dental appointments and the anxiety levels of patients, since there was a significant association between patients' feelings and their willingness to attend a dental appointment. Overall, patients undergoing dental treatment and orthodontics were more willing to attend an appointment and were more concerned about an increase in treatment duration.

The Effect of Hydrofluoric Acid Concentration and Heat on the Bonding to Lithium Disilicate Glass Ceramic

Abstract The aim of this study was to evaluate the effects of hydrofluoric acid (HF) concentration and previous heat treatment (PHT) on the surface morphology and micro-shear bond strength (mSBS) of a lithium disilicate glass ceramic (EMX) to resin cement. One hundred four EMX specimens were randomly assigned to two groups (n=52) according to the HF concentration: 5% and 10%. A new random distribution was made according to the PHTs (n=13): control (no PHT); previously heated HF (70 °C); previously heated EMX surface (85 °C); the combination of heated HF + heated EMX surface. The etching time was set at 20 s. All EMX blocks were silanated and received a thin layer of an unfilled resin. Five resin cement cylinders were made on each EMX surface using Tygon tubes as matrices, and then stored for 24 h at 37 °C. One random etched EMX sample from each group was analyzed using field-emission scanning electron microscopy (FE-SEM). The data were subjected to two-way ANOVA and multiple comparisons were performed using the Tukey post hoc test (a=0.05). For the control groups, 5% HF showed statistically lower mSBS values when compared to 10% HF (p<0.05). PHT increased the mSBS values for 5% HF, yielding statistically similar results to non-PHT 10% HF (p<0.05). FE-SEM images showed increased glassy matrix removal when PHT was applied to HF 5%, but not to the same degree as for 10% HF. PHT has the potential to improve the bond strength of 5% HF concentration on lithium disilicate glass ceramic.

Resumo O objetivo deste estudo foi avaliar os efeitos das concentrações de ácido fluorídrico (AF) e do prévio tratamento térmico (PTT) na morfologia da superfície e resistência de união ao microcisalhamento (mRUM) de uma cerâmica vítrea de dissilicato de lítio (EMX) ao cimento resinoso. Cento e quatro espécimes de EMX foram aleatoriamente distribuídos em dois grupos (n=52) de acordo com a concentração do AF: 5% e 10%. Os espécimes foram novamente distribuídos de forma aleatória de acordo com o PTT (n=13): controle (sem PTT); AF previamente aquecido (70 °C); superfície do EMX previamente aquecida (85 °C); combinação entre AF e EMX aquecidos. O tempo de condicionamento foi fixado em 20 s. Todos os espécimes de EMX foram silanizados e receberam a aplicação de uma fina camada de um adesivo sem carga. Cinco cilindros de cimento resinoso foram confeccionados usando tubos Tygon como matrizes e então armazenados por 24 h a 37 °C. Uma amostra condicionada de cada grupo foi aleatoriamente selecionada e analisada em um microscópio eletrônico de varredura em emissão de campo (MEVEC). Os dados foram submetidos ao teste ANOVA de dois fatores e múltiplas comparações foram feitas pelo teste de Tukey (a=0.05). Para os grupos controle, AF 5% mostrou valor de mRUM estatisticamente menor do que AF 10% (p<0.05). PTT aumentou os valores de mRUM para o AF 5%, proporcionando resultados estatisticamente similares ao grupo AF 10% controle (p<0.05). MEVEC mostrou um aumento na remoção da matriz vítrea quando o PTT foi aplicado ao grupo AF 5%, no entanto esse efeito não foi visto no grupo AF 10%. O PTT tem o potencial de melhorar a resistência de união do AF 5% na cerâmica vítrea reforçada por disilicato de lítio.

In situ assessment of the saliva effect on enamel morphology after microabrasion technique

AIM: This study evaluated saliva effects on enamel morphology surface after microabrasion technique. METHODS: Enamel blocks (16 mm2) obtained from bovine incisors were divided into 9 groups as follows: one control group (no treatment), four groups with microabrasion treatment using 35% phosphoric acid and pumice (H3PO4+Pum) and other four groups treated with 6.6% hydrochloric acid and silica (HCl+Sil). One group of each treatment was submitted to 4 frames of saliva exposure: without exposure, 1-h exposure, 24-h exposure, and 7-days exposure on in situ regimen. Nineteen volunteers (n=19), considered as statistical blocks, used an intraoral appliance containing the specimens, for 7 days. Enamel roughness (Ra) was tested before and after treatment, and after saliva exposure. Confocal laser scanning microscopy (CLSM) was used to evaluate qualitatively the enamel morphology. RESULTS: All groups exhibited increased Ra after microabrasion. With regards to saliva exposure, the treatment with HCl+Sil presented more susceptibility to the saliva action, but no period of time was efficient in re-establishing this characteristic compared with the control group. CLSM analysis showed reduction of the micro-abrasive damages during the experimental times. CONCLUSIONS: Seven days of saliva exposure were not sufficient for the treated enamel to reach its normal characteristics compared with the control group...

Physicochemical properties of enamel after microabrasion technique

AIM: This study aimed to evaluate the enamel microhardness, surface roughness, and chemical composition after microabrasion technique, followed by polishing and different immersion times in artificial saliva. Materials and methods: Ninety enamel blocks (25mm2) from bovine incisors were divided into two groups (G1 and G2), and then subdivided in five subgroups (n = 9) according to their microabrasion treatment and polishing with a diamond paste: 35% phosphoric acid and pumice (H3PO4+Pum) and polishing; just H3PO4+Pum; 6.6% hydrochloric acid and silica (HCl+Sil) and polishing; just HCl+Sil; and control (no treatment). For G1, roughness and microhardness analyses were performed before (L1) and after (L2) microabrasion. After 15 (L3) and 30 (L4) days of immersion in artificial saliva, microhardness analysis was also performed. After (L4) analysis, the specimens were subjected to SEM analysis. G2 was used for the chemical analysis using energy dispersion testing (EDS). The data was subjected to statistical analysis (α = 5%). For roughness, L2 presented higher values than L1, except for the polished groups. For microhardness, L2 presented higher values than L1, except for unpolished groups. The L3 and L4 did not differ and were higher than L1. RESULTS: No changes were observed in the phosphorus concentrations of the microabrasioned enamel. However, the specimens treated with HCl+Sil were observed as having decreased calcium and increased chlorine and silica on the EDS test. Conclusion: Microabrasion followed by polishing and immersion in artificial saliva for 15 days is enough to increase the microhardness of microabrasioned enamel surfaces, although the microabrasion procedure can alter the mineral content of the enamel.

Analysis of width/height ratio and gingival zenith in patients with bilateral agenesis of maxillary lateral incisor

OBJECTIVE: The purpose of this study was to evaluate the width/length ratio and the gingival zenith (GZ), by means of dental casts and digital caliper, in patients with missing maxillary lateral incisors after treatment. METHODS: The sample was composed of 52 subjects divided into 3 groups: BRG (n = 18), patients with bilateral agenesis treated with tooth re-contouring; BIG (n = 10) patients with agenesis treated with implants and CG (n = 24), control group. The data were analyzed using Shapiro-Wilk, Spearman correlation, Wilcoxon, Kruskal-Wallis, t test and ANOVA tests (p < 0.05). RESULTS: For the width/length ratio of the lateral incisors, BIG presented the lowest mean values (0.72 right and left), when compared with other groups. However, comparison between groups presented statistically significant differences for the right lateral incisor (BIG x CG) and for the canine (BRG x CG). GZ data evaluation showed the greatest difference for BRG (0.5 right and 0.48 left). BIG (0.95 right and 0.98 left) and CG (0.98 right and 0.8 left) presented more similar values, nevertheless, without statistical difference (p > 0.05). GZ data for the right and left sides of the smile were not considered statistically different. CONCLUSION: Although no statistical difference was found in the comparison between the groups, analysis of the descriptive values showed that group BIG showed the greatest difference in values with regard to width/length ratio. Regarding gingival zenith, BRG showed the greatest difference.

OBJETIVO: o propósito desse estudo foi analisar, por meio de modelos de estudo e paquímetro digital, a proporção largura/altura e o zênite gengival (ZG) em pacientes com agenesia bilateral do incisivo lateral superior após o tratamento. MÉTODOS: a amostra consistiu de 52 voluntários divididos em 3 grupos: GBR (n=18), pacientes com agenesia bilateral tratados com reanatomizações dentárias; GBI (n=10), pacientes com agenesia bilateral tratados com implantes; e GC (n=24), grupo controle. Os dados foram avaliados por meio dos testes de Shapiro-Wilk, Wilcoxon, Kruskal-Wallis, teste t, ANOVA (p<0,05) e correlação de Spearman. RESULTADOS: para a proporção largura/altura dos incisivos laterais, o GBI apresentou menores valores (0,72 direito e esquerdo), quando comparado aos demais. Porém, a comparação intergrupos revelou diferenças estatisticamente significativas para o incisivo lateral direito (GBI x GC) e para o canino (GBR x GC). A avaliação das medianas obtidas para o ZG demonstrou que o GBR foi o mais destoante (0,5 direito e 0,48 esquerdo), e que o GBI (0,95 direito e 0,98 esquerdo) e o GC (0,98 direito e 0,8 esquerdo) apresentaram valores semelhantes, sem diferença estatisticamente significativa (p>0,05). Os valores obtidos para os lados direito e esquerdo foram considerados iguais dentro de cada grupo. CONCLUSÃO: embora não tenham sido encontradas diferenças estatísticas na comparação entre os grupos, pela análise descritiva dos dados, o GBI foi o grupo que apresentou as medidas mais destoantes dos demais em relação à proporção largura/altura, sendo que, para o zênite gengival, a maior diferença observada foi no GBR.

Tratamento interdisciplinar para reabilitação estética do sorriso / Interdisciplinary treatment for esthetic rehabilitation of the smile

O anseio por um sorriso estético vem sendo cada vez mais o motivo pelo qual os pacientes procuram o tratamento odontológico. Dentro desse contexto, a Odontologia atual tem adotado uma abordagem multidisciplinar para a reabilitação estética e funcional do sorriso. A proposta deste trabalho foi apresentar um caso clínico solucionado por meio de um trabalho em equipe, envolvendo duas especialidades: a Ortodontia e a Dentística. A paciente queixava-se da aparência do seu sorriso. A partir de uma cuidadosa análise das características do complexo dentofacial da mesma, foi planejado um tratamento ortodôntico-restaurador. Coube à Ortodontia o nivelamento das arcadas, correção do zênite gengival e alinhamento do plano oclusal e dentário para distribuição dos espaços ortodônticos. A abordagem da Dentística consistiu na remoção das restaurações insatisfatórias e nos procedimentos para fechamento dos diastemas e recontorno cosmético dos dentes anterossuperiores com resina composta direta, restabelecendo princípios como tamanho e forma, linha do sorriso, bordas incisais e proporcionalidade. O caso apresentado reflete a importância do planejamento integrado, possibilitando uma abordagem restauradora minimamente invasiva, na reabilitação estética e funcional do sorriso de uma paciente com diastemas múltiplos.