Physical and Mechanical Properties of Bulk-Fill, Conventional, and Flowable Resin Composites Stored Dry and Wet.

Surface degradation, margin, and bulk fracture are common reasons that necessitate replacement of resin composite restorations. The purpose of this study was to determine filler weight (FW), fracture toughness (FT), Vickers hardness (VHN), sorption/solubility (S/S), and colour change (ΔE) of four resin composites in dry and wet conditions. Four resin composites of shade A2 were investigated: Aura bulk-fill (AB) (SDI), Tetric Evoceram (TE) (Ivoclar), G-ænial Universal Flo (GUF) (GC), and GC Kalore (GCK) (GC). For FT, VHN, and ΔE, the specimens were prepared, divided into 2 groups, and stored dry or immersed in distilled water. The specimens were subdivided into three subgroups and stored for 1, 7, and 60 days and then subjected to the relevant tests. Six fractured remnants were weighed for each material to measure FW%. To test S/S, ISO 4049 was used. The data were analysed using ANOVA and Tukey's test. There was an inverse correlation between FW and FT. A significantly higher FT was found for GUF. There were no significant differences between conditions in materials except for AB. The highest VHN was found for GCK and AB. After 1 and 7 days, a significant difference was observed in S/S between all materials with the highest values for GUF. There was a correlation between sorption and solubility. The material, the media, and aging have an influence on the properties of resin composites. It is important to emphasise that each material should be used for a specific clinical need based on their properties.

Microtensile bond strength of glass ionomer cements to a resin composite using universal bonding agents with and without acid etching.

OBJECTIVES: To assess the effect of two universal bonding agents on the microtensile bond strength (µTBS) of encapsulated conventional glass ionomers (CGICs) and resin-modified glass ionomers (RMGICs) to a resin composite, with or without the use of 35% phosphoric acid. METHODS: Four materials were used in this study: Riva Self-cure and Riva Light-cure; SDI and Equia Forte Fil and Fuji II LC; GC. The specimens were prepared in Teflon moulds with half the specimens for each GIC etched using 35% phosphoric acid (Ultra-Etch) and the remainder not etched. Each group was randomly subdivided into three groups, where the first two groups received an air-thin layer of bonding agent (G-Premio Bond = GPB or Clearfil Universal Bond = CUB) then light cured; and the third group had no bonding agent. For all groups, a nanohybrid composite (GC Kalore; GC) was placed incrementally on the GIC. Following 24 h immersion in distilled water, each block was embedded in epoxy resin in a cubic mould and sectioned by a cutting device. The stick specimens were then subjected to µTBS testing. RESULTS: The application of both universal bonding agents significantly enhanced the µTBS of all GICs (p < 0.001). Both RMGICs exhibited higher µTBS compared to that of CGICs (p < 0.001). The application of universal bonding agents with acid etching significantly increased the µTBS of both CGICs and RMGICs to resin composite in contrast to without acid etching. CONCLUSION: Using 35% phosphoric acid for 15 s prior to the application of universal bonding agents improved the µTBS of GIC to resin composite. CLINICAL SIGNIFICANCE: Using Universal bonding agents with 15 s acid etching may increase the bond strength of both CGICs and RMGICs to resin composite when utilising the sandwich technique.

Mathematical validation of measurement of root fracture resistance: an in vitro study.

BACKGROUND: The aim of this study was to develop a mathematically valid method of assessing fracture resistance of roots. The model developed used mesial roots of lower molars instrumented using stainless steel hand files (SS) and two rotary nickel-titanium (NiTi) systems. METHODS: Eighty human lower molars were selected and randomly divided into four groups (n = 20). After instrumentation, the root canals were obturated using thermoplasticized gutta percha. The roots were covered with a simulated periodontal ligament and mounted vertically in autopolymerizing acrylic in PVC tubes. Using a universal testing machine, the force to fracture (N) was applied and the maximum load (FL) was recorded. Remaining dentine volume was calculated and the fracture resistance (FR) was recorded. The data were analyzed using SPSS version 22 with P < .05. RESULTS: There were no significant differences among the instrumentation methods for FL but in FR the roots instrumented using rotary NiTi showed significantly lower values than control groups and SS files (P < 0.001). CONCLUSIONS: Considering the effect of root length, volume of the root, and volume of the instrumented canal as well as the maximum failure load may be a more objective method of reporting fracture resistance of roots.

Self-assessed impact of oral health on the psychological well-being and depressive symptoms of older adults living in Melbourne.

OBJECTIVES: This study aimed to investigate oral health-related factors affecting the self-assessed psychological well-being (PW) and depressive symptoms of independent-living Australians aged 79 years and over living in the community in metropolitan Melbourne. METHODS: The Melbourne Longitudinal Studies on Healthy Aging (MELSHA) program was used as the data source in this study and includes data on the health and well-being of older participants. The MELSHA baseline data collection occurred in 1994, the current study used data from the 2008 data collection and included 201 participants, who remained in the study. Data were analyzed using multiple linear regression (MLR) analysis with a stepwise procedure to identify the variables that accounted for a significant proportion of the variance in the participants' PW scores. RESULTS: Present findings indicate that oral health may play a significant mediating role in PW through maintaining a presentable and acceptable physical appearance. Some 16.4 percent of participants reported feeling concerned about their dental appearance, either "Sometimes," "Often," or "Very often." Multivariate analysis showed significantly influences on PW positive and negative affect scores (P < 0.0001); and depressive symptoms (P < 0.0001) by participants' dentition status, enjoyment of meals, self-reported feeling of concern about the appearance of the mouth, social activity and self-assessment of general health. Final models explained 17.8, 20.1, and 24.6 percent of the variance of PW positive, negative affect scores, and depressive symptoms, respectively. CONCLUSIONS: Oral health, specifically the appearance of the mouth and dentition, plays a significant role in the PW of older Melbournians. Future cross-sectional and longitudinal studies are indicated to raise awareness on the changes required to improve the quality of life of the older population.

Factors associated with self-reported dental visits among older melbournians: the MELSHA study 2008 data collection / Factores asociados con visitas dentales autoinformadas entre melbournianos mayores: el estudio MELSHA 2008 recopilación de datos

Objective: To describe self-reported oral health-care visits and associated factors in older adults in Melbourne, Australia. Material and Methods: 201 older adults, 79-96 years, took part in the Melbourne Longitudinal Studies on Healthy Ageing (MELSHA) in 2008. Participants who visited a dentist within 12-months prior were identified. Logistic regression examined factors associated with the 12-month visits. Results: 47.7% reported visits to the dentist in the previous 12 months. Multivariate analyses showed dentate participants (OR=11.27; 95% CI: 4.38-29.00) were more likely to have a 12-month visit, and; those receiving a government pension or benefit were less likely to have a 12-month visit (OR=0.38; 95% CI 0.18-0.79). Conclusion: Compared with existing data on the oral health of older Australians, MELSHA participants appear to have lower dental attendance. Findings highlight the need to increase older people sl eeking oral health-care, and the need to collect information to identify influencers of oral health service usage.

Objetivo: Describir las visitas de atención de salud bucal autoreportadas y los factores asociados en adultos mayores en Melbourne, Australia. Métodos: 201 adultos mayores, de 79 a 96 años, participaron en los Estudios longitudinales de Envejecimiento Saludable en Melbourne (MELSHA) en 2008. Se identificaron los participantes que visitaron a un dentista dentro de los 12 meses anteriores. La regresión logística examinó los factores asociados con haber visitado el dentists en los ultimos 12 meses. Resultados: el 47,7% informó visitas al dentista en los 12 meses anteriores. Los análisis multivariados mostraron que los participantes dentados (OR=11.27; IC 95%:4.38-29.00) tenían más probabilidades de haber visitado al dentista en los ultimos 12 meses; y aquellos que recibieron una pensión o beneficio del gobierno tenían menos probabilidades de haber reportado una visita en los ultimos 12 meses (OR=0,38; IC del 95%:0,18 a 0,79). Conclusión: en comparación con los datos existentes sobre la salud oral de los australianos adultos mayores, los participantes de MELSHA reportaron una menor asistencia dental. Los resultados resaltan la necesidad de aumentar que adultos mayores busquen atención de salud bucal, y la necesidad de recopilar información para identificar influyentes en el uso de servicios de salud bucal.

The effects of nanofilled resin-based coatings on the physical properties of glass ionomer cement restorative materials.

OBJECTIVES: To determine the effect of two resin-based coatings on the water sorption/solubility and colour change of three conventional and two resin modified glass ionomer cement restorative materials. METHODS: Five glass-ionomer cement (GIC) restorative materials and two nanofilled resin-based coatings were studied. Disc-shaped specimens of each material were prepared and divided into three groups, uncoated and coated with either of the two coatings tested (n = 8). Water sorption and solubility were measured in accordance with ISO 4049 and ISO 6876 instructions, respectively. For colour change, the specimens were immersed in distilled water for 24 h, then immersed for another 24 h and an extra week in the three solutions of lactic acid, coffee, and distilled water. The specimens were subjected to colour measurements, using a spectrophotometer after 24 h and 7 days of immersion. The colour change (ΔE) was calculated using a specific formula. ANOVA tests were used for data analysis. RESULTS: Two-Way ANOVA revealed a significant interaction between materials and coatings for the water sorption/solubility values. Fuji Bulk showed the lowest water sorption/solubility and the coated groups showed a lower mean sorption/solubility and ΔE. The ΔE varied depending on the materials and the solutions. CONCLUSIONS: Coating of GIC restoratives reduced the water sorption/solubility and ΔE of almost all materials with a significant decline in most of the materials. CLINICAL SIGNIFICANCE: Coating of GIC restorations in the oral environment with resin-based coating may protect the restorations from early water sorption/solubility and discolouration.