Comparative Effect of Calcium Mesoporous Silica Versus Calcium and/or Fluoride Products on the Reduction of Erosive Tooth Wear and Abrasive Enamel Lesion

Abstract Objective: To evaluate the effect of a calcium nanocompound on the reduction of erosive tooth wear and abrasion. Material and Methods: Bovine enamel specimens (BE), were randomly assigned to the following groups (n = 10): G1 = Calcium mesoporous silica nanoparticles (Ca2+MSNs); G2 = casein phosphopeptide-amorphous calcium phosphate (CPP-ACP, 2% CPP-ACP, GC®); G3 = casein phosphopeptide-amorphous calcium fluoride phosphate (CPP-ACFP, 2% CPP-ACP + 900 ppm F-, GC®); G4 = sodium fluoride NaF (900 ppm F-, positive control); and G5 = distilled and deionized water (negative control). Each product was applied to the exposed area for one minute, three times per day for three consecutive days, and followed by the immersion of the specimens in Sprite Zero™ - a low-pH solution (2.58) for five minutes (Coca-Cola™). After the first and last erosive challenges of the day, the specimens were submitted to abrasion in a toothbrush machine for 15 seconds (200 g/BE). The specimens were analysed using 3D non-contact optical profilometry, with tooth structure loss (TSL) measurements and scanning electron microscopy (SEM). TSL values were analysed by Kruskal-Wallis and Mann-Whitney tests (p<0.05). Results: There were no significant differences between G1 (10.95 µm) and G3 (10.80 µm) treatments for TSL values; however both resulted in significantly reduced TSL values compared with the G5 (16.00 µm) (p<0.05). The G4 (12.26 µm) showed no statistically significant difference when compared to the G5 (16.00 µm). The groups G1 and G3 presented higher surface preservation than the G5. Conclusion: Ca2+MSNs was effective for reducing tooth surface loss caused by erosive tooth wear and abrasion.

Evaluación del desgaste por cepillado, in vitro, de una resina compuesta, fotopolimerizada por lámpara halógena: en dos tiempos diferentes / Wear evaluation of the in vitro toothbrushing of a composite resin cured by halogent light curing: in two different times

El objetivo de este trabajo fue evaluar el desgaste abrasivo por cepillado in vitro de la resina compuesta 4Seasons, de dos colores diferentes (A3 y C4) y polimerizadas por dos diferentes tiempos (20 e 40 s), utilizando cepillo dental y dentífrico; también se uso como material de referencia, el PMMA. Fueron confeccionados 10 especímenes, para cada uno de los 5 grupos (PMMA, A3 20s, A3 40s, C4 20s, C4 40s). Después de su confección, cada espécimen era almacenado en agua desmineralizada a 37 ± 2 ºC, por 24 horas, regularizados con lija; después del lavado en ultrasonido, volvían a ser almacenados en las mismas condiciones por 7 días. El cepillado fue realizado en una máquina para desgaste por cepillado, aplicándose una carga de 3N, con frecuencia de 4,5 ciclos/seg; el período de cepillado de un espécimen comprendía 150,000 ciclos. Fueron realizados 5 lotes de cepillado, de modo que un espécimen de cada material de cada grupo fuese sometido a cada una de las posiciones ocupadas por los 10 cepillos. La cantidad de masa pérdida fue calculada por pesaje (pre y post cepillado). Este trabajo también fue ilustrado con gráficos de rugosidad y MEB. La tasa media de desgaste fue de 2,8 mg para PMMA, de 5,5 mg para A3-20s, 4,7 mg para A3-40 s, 5,4 para C4-20s y 4,2 mg para C4-40s. ANOVA mostro que no hubo diferencia significante entre los grupos, para p=0,166. Concluyéndose que no existió diferencia de resistencia al desgaste abrasivo entre los grupos

To evaluate abrasive wear, by weight changes, of a resin composite to in vitro toothbrushing, of two different colors (A3 and C4), cured by two times (20 and 40 s). Resin composite 4Seasons was material studied and PMMA was used as reference material. Ten cylindric samples 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± ºC, for 24 h, and then regularized by abrasive gritting with sandpaper, after that, were cleaned in ultrasound bath, and restored to the same described conditions, for 7 days. The toothbrushing was then conducted in a proper machine that holds 10 specimens, with 3 N load of each toothbrush on the respective sample using dentifrice and water. 150.000 cycles were applied per group. Five 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. Roughness and MEV were also evaluated. Data were analyzed with one-way ANOVA. 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). It was possible to conclude that difference of the resistance to the abrasive wear between the studied groups did not exist

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.

Abfracción. La lección dental del futuro. Parte I: etiopatogenia y características clínicas / Abfraction. The dental lesion of the future. Part I: etiopathogenesis and clinical features

Se denomina abfracción a la lesión en forma de cuña en el límite amelocementario (LAC) causada por fuerzas oclusales excéntricas que llevan a la flexión dental provocando la ruptura de prismas de esmalte, cemento y dentina. Los objetivos de este trabajo son: 1) comprender los mecanismos que generan la abfracción, su etiología, desarrollo y patología generada; 2) cuáles trabajos de investigación fundamentan la etiopatogenia de estas lesiones; 3) describir las características clínica; 4) valorar la abfracción y su importancia en el futuro como lesión en las próximas generaciones; 5) establecer las situaciones en que estas lesiones cervicales deben ser restauradas.

The effect of miswak and tooth brush filaments end-surface texture on enamel. A SEM pilot study.

OBJECTIVE: The aim of the study was to compare the abrasive effect of miswak and toothbrush filaments on enamel tooth surface. MATERIAL AND METHODS: Ten maxillary central incisors were obtained from Division of Maxillofacial Surgery, King Saud University, College of Dentistry. Twenty specimen were prepared, they were divided into 4 groups (1) Butler toothbrush; (2) Aquafresh toothbrush; (3) Miswak; (4) Control group. Miswak, Aquafresh 311 and Butler 311 tooth brush were used with light pressure in one direction motion for 60 seconds on enamel surface. The specimens were prepared for Scanning Electron Microscopy (SEM) examination. The middle filament from toothbrushes and miswak were also prepared for SEM. RESULTS: Showed that filaments end-surface texture play a major role in abrasive active activity and enamel tooth surface loss. CONCLUSION: The Butler 311 toothbrush and miswak showed lesser effect on enamel as compared to Aquafresh 311 toothbrush.

Lesiones cervicales no cariosas y su tratamiento / Non-carious cervical lesions and their treatment

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. Siendo la abfracción considerada la más asociada a la hipersensibilidad, se plantearán diferentes formas de tratamiento de la misma. Se mencionarán los diferentes procedimientos a realizar para su prevención y los materiales a utilizar para su restauración