Clinical comparison of marginal fit of ceramic inlays between digital and conventional impressions.

PURPOSE: The aim of this stuldy was to compare the clinical marginal fit of CAD-CAM inlays obtained from intraoral digital impression or addition silicone impression techniques. MATERIALS AND METHODS: The study included 31 inlays for prosthodontics purposes of 31 patients: 15 based on intraoral digital impressions (DI group); and 16 based on a conventional impression technique (CI group). Inlays included occlusal and a non-occlusal surface. Inlays were milled in ceramic. The inlay-teeth interface was replicated by placing each inlay in its corresponding uncemented clinical preparation and taking interface impressions with silicone material from occlusal and free surfaces. Interface analysis was made using white light confocal microscopy (WLCM) (scanning area: 694 × 510 µm2) from the impression samples. The gap size and the inlay overextension were measured from the microscopy topographies. For analytical purposes (i.e., 95-%-confidence intervals calculations and P-value calculations), the procedure REGRESS in SUDAAN was used to account for clustering (i.e., multiple measurements). For p-value calculation, the log transformation of the dependent variables was used to normalize the distributions. RESULTS: Marginal fit values for occlusal and free surfaces were affected by the type of impression. There were no differences between surfaces (occlusal vs. free). Gap obtained for DI group was 164 ± 84 µm and that for CI group was 209 ± 104 µm, and there were statistical differences between them (p = .041). Mean overextension values were 60 ± 59 µm for DI group and 67 ± 73 µm for CI group, and there were no differences between then (p = .553). CONCLUSION: Digital impression achieved inlays with higher clinical marginal fit and performed better than the conventional silicone materials.

Novel Ti surface coated with PVA hydrogel and chitosan nanoparticles with antibacterial drug release: An experimental in vitro study.

OBJECTIVES: The aims of this study were to design a novel titanium surface coated with a PVA hydrogel matrix and chitosan-based nanoparticles and to investigate the antibiotic release and its ability to inhibit microbial activity. METHODS: Two drug delivery systems were developed and mixed. Chitosan-based nanoparticles (NP) and a polyvinyl alcohol film (PVA). The size, ζ-potential, stability, adhesive properties, and encapsulation profile of NP, as well as the release kinetics of drug delivery systems and their antimicrobial ability of PVA and PVANP films, were studied on Ti surfaces. The systems were loaded with doxycycline, vancomycin, and doxepin hydrochloride. RESULTS: Nanoparticles presented a ζ-potential greater than 30 mV for 45 days and the efficiency drug encapsulation was 26.88% ± 1.51% for doxycycline, 16.09% ± 10.24% for vancomycin and 17.57% ± 11.08% for doxepin. In addition, PVA films were loaded with 125 µg/mL of doxycycline, 125 µg/mL of vancomycin, and 100 µg/mL of doxepin. PVANP-doxycycline achieved the antibacterial effect at 4 h while PVA-doxycycline maintained its effect at 24 h.

How Confinement and Back to Normal Affected the Well-Being and Thus Sleep, Headaches and Temporomandibular Disorders.

The COVID-19 pandemic is having negative consequences not only for people's general health but also for the masticatory system. This article aimed to assess confinement and its new normal impact on well-being, sleep, headaches, and temporomandibular disorders (TMD). An anonymous survey was distributed to a Spanish university community. Participants completed a well-being index (WHO-5), a questionnaire related to sleep quality (the BEARS test), a headache diagnostic test (the tension type headache (TTH) and migraine diagnosis test), and the DC-TMD questionnaire. Questions were addressed in three scenarios: before confinement, during confinement, and the new normal. A total of 436 responses were collected (70% women, 30% men). A reduction in well-being and sleep quality was recorded. Respondents reported more TTH and migraines during and after confinement. Overall, confinement and return to normal did not increase TMD symptoms, and only minor effects were observed, such as more intense joint pain and a higher incidence of muscle pain in women during confinement. Reduced well-being is correlated with sleep quality loss, headaches, and TMD symptoms. This study provides evidence that pandemics and confinement might have had a negative impact on population health. Well-being was strongly affected, as were sleep quality, depression risk, TTH, and migraine frequency. In contrast, the temporomandibular joint and muscles showed more resilience and were only slightly affected.

Ric-8A, a GEF for heterotrimeric G-proteins, controls cranial neural crest cell polarity during migration.

The neural crest (NC) is a transient embryonic cell population that migrates extensively during development. Ric-8A, a guanine nucleotide exchange factor (GEF) for different Gα subunits regulates cranial NC (CNC) cell migration in Xenopus through a mechanism that still remains to be elucidated. To properly migrate, CNC cells establish an axis of polarization and undergo morphological changes to generate protrusions at the leading edge and retraction of the cell rear. Here, we aim to study the role of Ric-8A in cell polarity during CNC cell migration by examining whether its signaling affects the localization of GTPase activity in Xenopus CNC using GTPase-based probes in live cells and aPKC and Par3 as polarity markers. We show that the levels of Ric-8A are critical during migration and affect the localization of polarity markers and the subcellular localization of GTPase activity, suggesting that Ric-8A, probably through heterotrimeric G-protein signaling, regulates cell polarity during CNC migration.

Influence of cavity preparation technique (rotary vs. ultrasonic) on microleakage and marginal fit of six end-root filling materials.

OBJECTIVES: To evaluate in vitro the effect of cavity preparation with microburs and diamond-coated ultrasonic tips on the microleakage and marginal fit of six end-root filling materials. STUDY DESIGN. The following materials were assessed: amalgam (Amalcap), zinc oxide eugenol (IRM), glass ionomer (Vitrebond), compomer (Cavalite), mineral particle aggregate (MTA) and composite (Clearfil). Cavity preparation was performed with microburs or diamond ultrasonic tips in single-root teeth. The seal was evaluated in two experiments: a microleakage assay on the passage of dye to the interface; and a scanning electron microscopy study and analysis of epoxy resin replicas, measuring the size of gaps in the interface between filling material and cavity walls. Multifactorial ANOVA, multiple comparison test and Student 's t test were used for statistical analyses of the data, considering p <0.05 to be significant. RESULTS: Clearfil and MTA achieved a hermetic seal. Leakage and interface gap size was greater with Cavalite than with Clearfil and MTA, followed by Vitrebond and IRM. The worst seal was obtained with Amalcap. The use of diamond-coated ultrasonic tips improved the seal and reduced the gap when using materials that did not hermetically seal the cavity (Amalcap, IRM, Cavalite, Vitrebond). The preparation technique did not affect materials that achieved a hermetic seal (Clearfil, MTA). CONCLUSIONS: Clearfil and MTA obtained a hermetic seal due to their excellent marginal fit and are the most recommended materials for clinical use, taking account of their sealing capacity. Ultrasonic cavity preparation is preferable because it improves the seal and marginal fit of materials that do not achieve a hermetic seal of the cavity (Amalcap, IRM, Cavalite, Vitrebond).

Effect of pulp pressure on the micropermeability and sealing ability of etch & rinse and self-etching adhesives.

This research evaluated the effect of pulp pressure on the micropermeability and sealing ability of etch & rinse and self-etching adhesives. Two etch & rinse adhesives (Prime&Bond NT and Admira Bond) and one self-etching adhesive (Xeno III) were used. Adhesive layer micropermeability was evaluated by using confocal laser scanning microscopy (CLSM). Eighteen molars were connected to a pulp pressure device and divided into two groups. One group was restored with pulp pressure and the other group without. Each group was divided into three subgroups according to the adhesive used. The adhesives were rhodamine-labeled and Class V cavities were restored. After restoration, all specimens were kept under pulp pressure conditions for 24 hours with fluorescein-labeled pulp fluid. The specimens were sectioned and the axial wall was observed under CLSM. A microleakage test was performed to evaluate the sealing. Thirty molars were divided into two groups. One group was prepared with a pulp pressure device and the other group without. Each group was divided into three subgroups as a function of the adhesive used. Class V cavities were restored and the specimens were immersed in fuchsin and sectioned. Microleakage and dentin penetration were recorded in the occlusal and gingival walls. A CLSM study showed that the etch & rinse adhesives had higher micropermeability compared to the self-etching adhesives and pulp pressure made all the adhesives more permeable. In the occlusal wall, the best sealing (hermetic) was obtained when etch & rinse adhesives were used. Xeno obtained the lowest occlusal sealing values. In the gingival wall, Xeno obtained the best sealing, followed by Admira and Prime&Bond. Pulp fluid decreased gingival wall sealing when etch & rinse adhesives were used but not when self-etching adhesive was used.

Microleakage of Class V composite restorations placed with etch-and-rinse and self-etching adhesives before and after thermocycling.

PURPOSE: To evaluate the sealing ability of etch-and-rinse and self-etching adhesives in Class V cavities before and after thermocycling in vitro. MATERIALS AND METHODS: Etch-and-rinse adhesives (Prime & Bond NT [P&B], XP Bond [XPB], Scotchbond 1 XT [SBX], Syntac [SYN]) and self-etching adhesives (Xeno III [XNO], i-Bond [IBO], Clearfil SE Bond [CLF]) were used. A microleakage test was performed to evaluate marginal sealing. Seventy molars were divided into seven groups according to the adhesive used. Class V cavities were restored and each group was divided into two subgroups. One group was water immersed for 24 h and the other was thermocycled. Then, specimens were immersed in fuchsin and sectioned. Microleakage and dentin permeability were recorded on occlusal and gingival walls and data were statistically analyzed. RESULTS: Etch-and-rinse adhesives provided perfect occlusal sealing. Self-etching adhesives obtained slight occlusal leakage. In the gingival wall, XNO and CLF showed the lowest leakage, followed by XPB and SBX, then P&B. SYN and IBO exhibited the highest leakage. All SE adhesives and XPB provided sealed dentinal tubules. Thermocycling did not affect the occlusal sealing but reduced the gingival sealing when P&B, SYN, XNO, CLF, and IBO were used. CONCLUSION: In enamel, marginal leakage was prevented when phosphoric acid was used. Self-etching adhesives promoted slight occlusal leakage. The gingival sealing was poorer than the occlusal sealing. XNO, CLF followed by XPB obtained the best gingival sealing. Thermocycling did not affect the occlusal bonding but reduced the gingival sealing, except when XPB and SBX were used.

Effect of cooled composite inserts in the sealing ability of resin composite restorations placed at intraoral temperatures: an in vitro study.

Polymerization shrinkage causes microleakage of resin composite restorations. New materials and operative techniques should be developed in order to reduce polymerization shrinkage. This research studied the effects of cooled composite inserts and room-temperature composite inserts in the sealing ability of resin composite restorations placed at intraoral temperatures. Forty-eight extracted human molars (providing a total of 155 sections) were kept at intraoral temperatures, and Class V cavities were restored with an ormocer-based resin composite (Admira, Voco). Three restorative techniques were used: conventional bulk insertion (Group I or control group) (n = 53 sections), room-temperature resin composite inserts (Group II) (n = 52) and cooled resin composite inserts (Group III) (n = 50). Microleakage and penetrating microleakage were studied under the microscope. Cooled composite inserts reduce microleakage at the gingival margins with respect to Groups I (p = 0.002) and II (p = 0.014). When small-size cooled composite inserts were used, the sealing ability at the gingival margins of Class V composite restorations was improved with respect to the bulk insertion technique and the room-temperature composite inserts technique.