Fabrication of controlled porous and ultrafast dissolution porous microneedles by organic-solvent-free ice templating method

Porous Microneedles (PMNs) have been widely used in drug delivery and medical diagnosis owing to their abundant interconnected pores. However, the mechanical strength, the use of organic solvent, and drug loading capacity have long been challenging. Herein, a novel strategy of PMNs fabrication based on the Ice Templating Method is proposed that is suitable for insoluble, soluble, and nanosystem drug loading. The preparation process simplifies the traditional microneedle preparation process with a shorter preparation time. It endows the highly tunable porous morphology, enhanced mechanical strength, and rapid dissolution performance. Micro-CT three-dimensional reconstruction was used to better quantify the internal structures of PMNs, and we further established the equivalent pore network model to statistically analyze the internal pore structure parameters of PMNs. In particular, the mechanical strength is mainly negatively correlated with the surface porosity, while the dissolution velocity is mainly positively correlated with the permeability coefficient by the correlation heatmap. The poorly water-soluble Asiatic acid was encapsulated in PMNs in nanostructured lipid carriers, showing prominent hypertrophic scar healing trends. This work offers a quick and easy way of preparation that may be used to expand PMNs function and be introduced in industrial manufacturing development.

Marginal adaptation of bulk-fill resin composites with different viscosities in class II restorations: a micro-CT evaluation

BACKGROUND

The purpose of this study is to evaluate the marginal adaptation of bulk-fill resin composites with different viscosities (paste-like and flowable) in Class II restorations using micro-CT imaging.

METHODS

Forty extracted human molars were used. Mesial and distal Class II box cavities (approximately 3 mm x 3 mm x 4 mm) were prepared for each tooth, with cavity floors located 1 mm below the enamel-cementum junction. Following adhesive application, teeth were restored using eight different groups: Group XB: X-tra Base Bulk-fill Flowable (VOCO), Group XF: X-tra Fill Bulk-fill (VOCO), Group FB: Filtek Bulk-fill Posterior (3 M ESPE), Group FF: Filtek Bulk-fill Flowable (3 M ESPE), Group BB: Beautifil-Bulk (SHOFU), Group BF: Beautifil-Bulk Flowable (SHOFU), and Group CO: "as a control group", Clearfil Majesty Posterior (KURARAY) and Group CF: "as a control group", Clearfil Majesty Flow + Clearfil Majesty Posterior (KURARAY). The restored teeth underwent an aging protocol involving 1000 cycles in a water bath fluctuating between 5 ± 1.0 °C and 55 ± 1.0 °C. Post-aging, teeth were immersed in 50% silver nitrate solution for 24 h and then in a film developer solution for 8 h. Microleakage analysis was performed using micro-CT, evaluated with 3D Slicer software. A two-way ANOVA was employed for statistical analysis.

RESULTS

Two-way ANOVA results indicated significant effects of both viscosity (p < 0.0001) and composite type (p < 0.0001) on marginal adaptation. Viscosity analysis (comparing flowable and paste-like) revealed no significant differences in the FB-FF, XB-XF and BB-BF groups but significant differences in the and CO-CF group, with flowable type exhibiting less microleakage than paste-like type.

CONCLUSIONS

The study suggests that while the viscosity of bulk-fill composites did not significantly affect marginal adaptation, the brand of bulk-fill composite did influence it.

Efficiency of the new reciprocating and rotary systems with or without ultrasonics in removing root-canals filling with calcium silicate-based sealer (MTA)

BACKGROUND

To compare the efficiency of endodontic rotary and reciprocating systems in removing calcium silicate-sealer based fillings and to investigate the impact of passive ultrasonic irrigation (PUI) on their efficiency.

MATERIALS AND METHODS

160 root-canals were instrumented, filled with gutta-percha and calcium silicate based-sealer and divided into 10 equal groups. Five groups in which the reciprocating systems (WaveOne-Gold, Reciproc-Blue and R-Motion) and rotary systems (Fanta-AF-One and Tango-Endo) were used to remove root-canals' fillings. In the other five groups the fillings were removed by the same systems then additionally with PUI. The times to complete retreatments procedures were recorded. Micro-computed tomography's analysis of the root-canals fillings' volume before and after retreatments was used to determine the remaining filling materials (RFMs) volumes.

RESULTS

The RFMs after using rotary systems (10.1%) was greater than after using reciprocating systems (3.8%) (P < 0.001). The RFMs after using WOG (2%) and RB systems (2.6%) were less than those in the RM (6.8%), TE (9.5%) and FAFO (10.7%) systems [P < 0.05]. The times required to remove the filling materials using the TE (3.7 min), FAFO (4.1 min) and RM (4.1 min) systems were shorter than those required by the RB (5.4 min) and WOG (4.9 min) systems [P < 0.05]. Using PUI resulted in less RFMs (1.44%) when compared to using only rotary or reciprocating systems (6.27%) [P < 0.001].

CONCLUSIONS

Endodontic reciprocation systems were more effective, but needed longer times than rotary systems in removing calcium silicate based- sealers fillings. The PUI significantly improved removal of the root-canals' filling materials.

CLINICAL RELEVANCE

Reciprocating systems and PUI are recommended whenever root-canals retreatment is considered regardless of using calcium silicate-based sealers.

Efficiency of reciprocating systems reciprocated at different angles in removing root-canals fillings with an MTA-type sealer: an Ex-vivo study

BACKGROUND

There have been no reports on the impact of different reciprocating angles on retreatment performance of reciprocating files. This ex-vivo study compared the efficiency of three reciprocating systems in removing MTA-type sealer-based filling materials and investigated the influence of different reciprocating angles on their retreatment ability.

METHODS

140 root-canals were instrumented to a 35 apical size and filled with an MTA-type sealer and gutta-percha cones. Samples were scanned by micro-computed-tomography and the root-canals fillings volumes were measured. Samples were divided into 7 groups according to the reciprocating angles at which the WaveOne-Gold (WOG), Reciproc-Blue (RB) and R-Motion (RM) systems were reciprocated to remove the root-canals' fillings. The WOG-150/30, WOG-90/30, RB-150/30, RB-90/30, RM-150/30 and RM-90/30 groups in which the systems were reciprocated at 150/30 and 90/30 (counterclockwise/clockwise) angles. In the RB-270/30 group the RB system was reciprocated at 270/30 angles. Samples were re-scanned and the remaining filling materials' (RFMs) volumes were measured. The percentage of the RFMs volume and its mean value for each group were calculated and data were statistically analysed at 0.05 significance level.

RESULTS

The WOG system resulted in less RFMs (2.24%) when reciprocated at 90/30 angles compared to that resulted from the 150/30 angles (4.96%) [P = 0.002]. The RB system reciprocated at 90/30 angles resulted in less RFMs (2.67%) compared to that resulted from the 270/30 angles (6.64%) [P = 0.001]. The RFMs after using RM system reciprocated at 90/30 (6.02%) and 150/30 (7.61%) were greater than those of WOG (2.24 and 4.96%) and RB (2.67 and 4.34%) reciprocated at the same angles (P < 0.05). The longest time required to remove the filling materials was recorded with the RB-270/30 group (6.06 min) [P = 0.00]. The times required when the WOG, RB and RM files reciprocated at 90/30 angles (3.59, 3 and 3.05 mins, respectively) were shorter than those when files were reciprocated at 150/30 angles (5.25, 4.98 and 3.67 min, respectively) [P < 0.05].

CONCLUSIONS

The WOG and RB systems removed more MTA-type sealer-based root-canals fillings than the RM system. Lower counterclockwise reciprocating angles improve the retreatment ability of reciprocating systems, especially the WOG system and can reduce the time required for retreatment procedures.

A neoflavonoid dalsissooal isolated from heartwood of Dalbergia sissoo Roxb. has bone forming effects in mice model for osteoporosis

Dalbergia sissoo Roxb. is a well known medicinal plant of India, enriched with various flavonoids used for treating multiple diseases. Earlier, we have shown that extract of Dalbergia sissoo Roxb. leaves mitigate ovariectomy induced bone loss and pure compounds (neoflavonoids) isolated from it, promote osteoblastogenesis in primary calvarial osteoblasts cells in vitro. Here, we hypothesize that dalsissooal (DSL), a novel neoflavonoid isolated from the heartwood of Dalbergia sissoo Roxb. is an important constituent of the extract that imparts bone forming effects. Treatment with DSL enhanced trabecular bone micro-architecture parameters, biomechanical strength, increased bone formation rate and mineral apposition rate in OVx mice comparable to 17β-estradiol. It increased bone formation by enhancing osteoblast gene expression and reduced bone turnover by decreasing osteoclastic gene expressions. Interestingly, we observed that DSL has no uterine estrogenic effects. At cellular levels, DSL promoted differentiation of bone marrow cells as well as calvaria osteoblast cells towards osteoblast lineage by enhancing differentiation and mineralizing ability to form mineralizing nodules via stimulating BMP-2 and RunX-2 expressions. Overall, our data suggest that oral supplementation of a novel neoflavonoid dalsissooal isolated from heartwood of Dalbergia sissoo Roxb. exhibited bone anabolic action by improving structural property of bone, promoting new bone formation and reducing bone turnover rate in post-menopausal model for osteoporosis with no uterine hyperplasia.

Effects of ovariectomy on periodontal tissues following tooth replantation

OBJECTIVES

The aim of the study was to analyze the effects of ovariectomy on periodontal tissues following immediate tooth replantation by histomorphometric, immunohistochemistry, and μCT analysis.

MATERIALS AND METHODS

Eighty wistar rats (Rattus norvegicus albinos) with normal estrous cycles were randomly divided into two groups: ovariectomized (OVX) and Sham. Two months after surgery, the rats' upper right incisor was extracted followed by immediate reimplantation. The animals were sacrificed after 28, 45, and 60 days healing time. Histomorphometric and immunohistochemical analysis were performed by evaluation of PCNA and TRAP straining.

RESULTS

The periodontal ligament was reinserted into the bone and cementum in the both groups. The immunohistochemical analysis revealed PCNA positive cells on the periodontal ligament in both groups at 28 days. Root resorption was noted at 45 days with immunoreactive cells for TRAP present in bone and tooth surface however no statistical differences between the groups were noticed. Histomorphometric analysis showed significant difference between groups in the periodontal ligament and root resorption parameters for the sub-items: intensity of chronic inflammatory infiltrate at 60 days (p<0.01), the organization of the periodontal ligament at 28 days (p<0.05), depth of root resorption at 45 days (p<0.05) and at 60 days (p<0.001). The μCT analysis showed multiple areas of bone resorption in association with OVX at 28 and 60 days with no significant differences between times in vivo.

CONCLUSION

The ovariectomy did not have significant influence in periodontal tissue parameters following tooth reimplantation.