Aim This study aimed to evaluate the effect of frozen storage on the physical properties of a silicone-based test food material, highly used to evaluate the masticatory performance in research settings. Methods A total of 1,666 silicone cubes of Optosil Comfort® with 5.6-mm edges were shaped and stored at -18°C. The cubes were subsequently tested for flexural strength (maximum force, displacement, stress, and strain) before breaking (n = 136), changes in weight and size (n = 170), and masticatory performance (n = 1360) at eight timepoints: immediately after cube preparation (baseline, no freezing), and 1, 2, 3 and 4 weeks, and 2, 4 and 6 months after frozen storage. The cubes were thawed 8 h before each assessment. Results The maximum force, stress, maximum displacement, and deformation values for the cubes were not affected by freezing (P > 0.05). At all of the time points, the cubes exhibited similar weight (P = 0.366) and size (identical values). The masticatory performance for the cubes also showed no differences from baseline through 6 months (P = 0.061). Conclusion Freezing Optosil Comfort® silicone cubes did not alter the physical and mechanical properties of the material, being suitable to optimize the assessment of masticatory parameters for research purposes.

The aim of this study was to evaluate the reproducibility of the condensation silicone Optosil Comfort® as an artificial test food for masticatory performance evaluation. Twenty dentate subjects with mean age of 23.3 ± 0.7 years were selected. Masticatory performance was evaluated using the simple (MPI), the double (IME) and the multiple sieve methods. Trials were carried out five times by three examiners: three times by the first, and once by the second and third examiners. Friedman’s test was used to find the differences among time trials. Reproducibility was determined by the intra-class correlation (ICC) test (α = 0.05). No differences among time trials were found, except for MPI-4 mm (p = 0.022) from the first examiner results. The intra-examiner reproducibility (ICC) of almost all data was high (ICC ≥ 0.92, p < 0.001), being moderate only for MPI-0.50 mm (ICC = 0.89, p < 0.001). The inter-examiner reproducibility was high (ICC > 0.93, p < 0.001) for all results. For the multiple sieve method, the average mean of absolute difference from repeated measurements were lower than 1 mm. This trend was observed only from MPI-0.50 to MPI-1.4 for the single sieve method, and from IME-0.71/0.50 to IME-1.40/1.00 for the double sieve method. The results suggest that regardless of the method used, the reproducibility of Optosil Comfort® is high.

This study compared the microleakage of class V restorations bonded with various one-step self-etching adhesives. Seventy class V resin-based composite restorations were prepared on the buccal and lingual surfaces of 35 premolars, by using: Clearfil S 3 Bond, G-Bond, iBond, One Coat 7.0, OptiBond All-In-One, or Xeno IV. The Adper Single Bond etch-and-rinse two-step adhesive was employed as a control. Specimens were thermocycled for 500 cycles in separate water baths at 5°C and 55°C and loaded under 40 to 70 N for 50,000 cycles. Marginal microleakage was measured based on the penetration of a tracer agent. Although the control showed no microleakage at the enamel margins, there were no differences between groups (p = 0.06). None of the adhesives avoided microleakage at the dentin margins, and they displayed similar performances (p = 0.76). When both margins were compared, iBond® presented higher microleakage (p < 0.05) at the enamel margins (median, 1.00; Q3–Q1, 1.25–0.00) compared to the dentin margins (median, 0.00; Q3–Q1, 0.25–0.00). The study adhesives showed similar abilities to seal the margins of class V restorations, except for iBond®, which presented lower performance at the enamel margin.

This study evaluated the relationship among malocclusion, number of occlusal pairs, masticatory performance, masticatory time and masticatory ability in completely dentate subjects. Eighty healthy subjects (mean age = 19.40 ± 4.14 years) were grouped according to malocclusion diagnosis (n = 16): Class I, Class Class II-2, Class III and Normocclusion (control). Number of occlusal pairs was determined clinically. Masticatory performance was evaluated by the sieving method, and the time used for the comminute test food was registered as the masticatory time. Masticatory ability was measured by a dichotomic self-perception questionnaire. Statistical analysis was done by one-way ANOVA, ANOVA on ranks, Chi-Square and Spearman tests. Class II-1 and III malocclusion groups presented a smaller number of occlusal pairs than Normocclusion (p < 0.0001), Class I (p < 0.001) and II-2 (p < 0.0001) malocclusion groups. Class I, and III malocclusion groups showed lower masticatory performance values compared to Normocclusion (p < 0.05) and Class II-2 (p < 0.05) malocclusion groups. There were no differences in masticatory time (p = 0.156) and ability (χ2 = 3.58/p= 0.465) among groups. Occlusal pairs were associated with malocclusion (rho = 0.444/p < 0.0001) and masticatory performance (rho = 0.393/p < 0.0001), but malocclusion was not correlated with masticatory performance (rho = 0.116/p= 0.306). In conclusion, masticatory performance and ability were not related to malocclusion, and subjects with Class I, II-1 and III malocclusions presented lower masticatory performance because of their smaller number of occlusal pairs.

The aim of this study was to determine the reproducibility, reliability and validity of measurements in digital models compared to plaster models. Fifteen pairs of plaster models were obtained from orthodontic patients with permanent dentition before treatment. These were digitized to be evaluated with the program Cécile3 v2.554.2 beta. Two examiners measured three times the mesiodistal width of all the teeth present, intercanine, interpremolar and intermolar distances, overjet and overbite. The plaster models were measured using a digital vernier. The t-Student test for paired samples and interclass correlation coefficient (ICC) were used for statistical analysis. The ICC of the digital models were 0.84 ± 0.15 (intra-examiner) and 0.80 ± 0.19 (inter-examiner). The average mean difference of the digital models was 0.23 ± 0.14 and 0.24 ± 0.11 for each examiner, respectively. When the two types of measurements were compared, the values obtained from the digital models were lower than those obtained from the plaster models (p < 0.05), although the differences were considered clinically insignificant (differences < 0.1 mm). The Cécile digital models are a clinically acceptable alternative for use in Orthodontics.

El propósito del estudio fue evaluar el rendimiento masticatorio a través del estado oclusal. Fueron evaluados 100 sujetos. El rendimiento masticatorio fue evaluado a través del grado de trituración de pastillas de silicona y análisis de tamizado. El estado oclusal fue medido a través de la contabilización de pares oclusales anteriores y posteriores, y convertidos a unidades oclusales, asignando un valor agregado a cada tipo de par oclusal. Los resultados fueron evaluados a través de las pruebas de Kruskal Wallis, U-Mann Whitney, Spearman, y regresión múltiple stepwise. Se encontrron diferencias estadísticamente significativas entre los grupos de pares y unidades oclusales con respecto al rendimiento masticatorio (p<.001). El rendimiento masticatorio presentó una correlación muy fuerte con los pares oclusales (+.930) y unidades oclusales (+.919); considerable con los pares oclusales posteriores (+.877), pares molares (+.835) pares premolares (+.796); moderada con los pares anteriores (+.757) y la edad (-.679). Bajo las condiciones de este trabajo, aquellos sujetos con menor número de pares y unidades oclusales presentaron menor rendimiento masticatorio. La valorización de los pares como unidades oclusales ofrece una mejor descripción del potencial masticatorio de los dientes según el rendimiento obtenido.

The aim of this study was to assess masticatory performance through occlusal state. One hundred subjects with general health were evaluated. The masticatory performance was evaluated through the degree of crushing of pills of silicone and sieving test. The oclusal state was measured through the accounting of occlusal anterior and posterior pairs, and turned to occlusal units, assigning an aggregate value to each type of occlusal pair. The results were evaluated through the tests of Kruskal Wallis, U-Mann Whitney, Spearman, and stepwise multiple regression. There were statistically significant differences between the groups of occlusal pairs and units with respect to the masticatory performance (p<.001). The masticatory performance presented very hard correlation with the occlusal pairs (+.930) and occlusal units (+.919); considerable with the posterior occlusal pairs (+.877), molar pairs (+.835) and premolar pairs (+.796); and moderate with the anterior pairs (+.757) and with the age (- 679). Under the conditions of this work, those subjects with less number of occlusal pairs and units presented less masticatory performance. The valuation of the occlusal pairs as occlusal units offers one better description of the masticatory potential of the teeth according to the masticatory performance obtained.