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In conclusion, the concomitant use of face shield and surgical mask or N95/FFP2 respirator, and a 0.5 vol% H2O2-containing cooling spray, seems to confer a very high level of protection, drastically reducing the possibility of coronavirus transmission during the execution of dental procedures.

An implant-supported crown represents an established and validated option for single-tooth replacement; however, a restorative solution should be selected according to a wide number of factors including patient's desire, expectations, specific clinical conditions, and financial possibilities. The aim of this case report is to describe a conservative rehabilitation strategy for the replacement of a periodontally compromised mandibular incisor: the extracted natural tooth was used as a pontic bonded to adjacent elements with polyethylene fiber and resin composite. This way, a chairside fabrication of a resin-bonded fiber-reinforced prosthesis is possible, using the patient's own tooth. After showing a satisfactory functional and esthetic result, advantages and pitfalls of this technique along with available data on the literature regarding the natural tooth pontic are addressed. Both patients and clinicians should be aware of minimally invasive, successful solutions for single-tooth replacement; whether indicated or necessary, the natural tooth pontic technique leaves open other treatment options for the future.

An implant-supported crown represents an established and validated option for single-tooth replacement; however, a restorative solution should be selected according to a wide number of factors including patient’s desire, expectations, specific clinical conditions, and financial possibilities. The aim of this case report is to describe a conservative rehabilitation strategy for the replacement of a periodontally compromised mandibular incisor: the extracted natural tooth was used as a pontic bonded to adjacent elements with polyethylene fiber and resin composite. This way, a chairside fabrication of a resin-bonded fiber-reinforced prosthesis is possible, using the patient’s own tooth. After showing a satisfactory functional and esthetic result, advantages and pitfalls of this technique along with available data on the literature regarding the natural tooth pontic are addressed. Both patients and clinicians should be aware of minimally invasive, successful solutions for single-tooth replacement; whether indicated or necessary, the natural tooth pontic technique leaves open other treatment options for the future.

PURPOSE: To investigate the micro push-out bond strength of individually formed (everStick Post) and prefabricated (GC Fiber Post) fiber- reinforced composite (FRC) posts cemented with three different types of self-adhesive composite cements. MATERIALS AND METHODS: Forty-two single-rooted human teeth were decoronated, endodontically treated, and had post spaces prepared for everStick Post (n = 21) or GC Fiber Post (n = 21). The teeth were randomly divided into three subgroups (n = 7), and posts were cemented either with G-CEM LinkAce (GC), SpeedCEM (Ivoclar Vivadent) or RelyX U200 (3M Oral Care). Specimens were then perpendicularly sectioned and divided at the cementoenamel junction into two root levels: coronal or apical. A micro push-out test was performed using an 0.8-mm-wide stainless steel plunger. Bond strength was calculated in MPa by dividing the fracture load (N) by the bonded surface area (mm2). Log-transformed data was statistically analyzed using factorial ANOVA and Tukey's post-hoc test (α < 0.05). Fracture modes were determined employing a stereomicroscope, and differences were evaluated using a likelihood ratio test and Pearson's chi-squared test. Specimens were also observed using SEM. RESULTS: Bond strengths were significantly affected by both post type and root level (p < 0.05), but not by self-adhesive cement (p > 0.05). Fracture types showed a significantly higher prevalence of adhesive fractures at the apical level, with all fractures starting at the cement-dentin interface. CONCLUSION: Individually formed FRC posts demonstrated greater bond strength than their prefabricated FRC counterparts. The apical level of the luted posts yielded lower bond strengths than the coronal level. Failures were predominantly adhesive at the cement-dentin interface.

Uvod: Utvrditi “push-out” čvrstoću svezivanja za dentin i način loma, tri materijala za retrogradno punjenje temeljena na kalcij- silikatu nakon ultrazvučne izrade retrogradnih kaviteta. Materijali i postupci: Korijenski kanali 30 izvađenih, jednokorijenskih humanih, trajnih were endodontically treated, the apical 3 mm of each root was resected, and 3 mm rootend preparations were made using an ultrasonic tip. These teeth were randomly divided into three groups (n = 10) according to the root-end filling material used: 1) Micro- Mega mineral trioxide aggregate (MM- MTA), 2) Biodentine, and 3) TotalFill root repair material (RRM). The micro push-out test was performed using a universal testing machine, and the failure mode was analyzed using a stereomicroscope. The data were statistically analyzed using the one-way ANOVA and Tukey- Kramer HSD post-hoc tests (p < 0.05). Results: The TotalFill RRM had the highest bond strength of 13.44 ± 2.62 MPa, which was significantly different when compared to the Biodentine and MM- MTA (p < 0.05). The Biodentine and MM- MTA had bond strengths of 8.93 ± 2.62 and 8.40 ± 2.78, respectively, with no significant difference between them (p > 0.05). The MM-MTA showed only adhesive and mixed types of failures. The Biodentine and TotalFill RRM showed predominantly mixed types of failures, but also had adhesive and cohesive types present. Conclusion: The TotalFill RRM showed a higher bond strength when compared to the Biodentine and MM-MTA.

Svrha: Željelo se in vitro istražiti učinak ispiranja aktiviranog različitim erbijskim laserima na čvrstoću vezivanja individualnog kolčića ojačanog vlaknima na dentin korijenskog kanala. Materijali i metode: Dvadeset i sedam jednokorijenskih zuba endodontski su tretirani i poslije preparacije za postavljanje intrakanalnog kolčića podijeljeni u tri skupine (n = 9 po skupini), ovisno o vrsti predtretmana korijenskog dentina: 1. skupina – konvencionalno ispiranje fiziološkom otopinom (kontrolna skupina) ; 2. skupina – ispiranje fiziološkom otopinom i aktivacija PIPS nastavkom lasera Er:YAG ; 3. skupina – ispiranje i aktivacija RFT2 nastavkom lasera Er, Cr:YSGG. Dva uzorka iz svake skupine upotrijebljena su za SEM analizu. U preostale je (n = 7 po skupini) cementiran individualni kolčić ojačan vlaknima everStick POST – korišten je samoadhezivni cement G-CEM LinkAce. Nakon cementiranja uzorci su prerezani okomito na uzdužnu os na nove jedan milimetar debele uzorke koji su podvrgnuti push-out testiranju (0, 5 mm/min.). Rezultati su zabilježeni u MPa-u, a logaritmirani i statistički analizirani su ANOVA testom na razini značajnosti od 5 posto. Rezultati: U kontrolnoj skupini zaostatni sloj bio je još prisutan, u skupni Er:YAG bio je uklonjen, a u skupini Er, Cr:YSGG bio je djelomično uklonjen. U skupini Er, Cr:YSGG postignute su najviše vrijednosti čvrstoće vezivanja, slijedila je kontrolna skupina i tek tada skupina Er:YAG. Ipak, među vrijednostima čvrstoće vezivanja spomenutih skupina nije pronađena statistički značajna razlika (p = 0, 564). Zaključak: Ispiranje aktivirano nastavcima erbijskih lasera PIPS i RFT2 nije utjecalo na čvrstoću vezivanja individualnih kolčića ojačanih vlaknima na dentin korijenskog kanala.

The objective of this in vitro study was to examine the influence of two erbium lasers on bond strength of prefabricated and individually formed fiber reinforced composite (FRC) posts. One hundred twenty six single- rooted human teeth were decoronated, endodontically treated and after post space preparation on divided in two groups (n=63 per group) depending on the type of FRC posts, prefabricated GC Fiber Post and individually formed everStick Post. Each group was further subdivided into three groups (n=21 per group), according to the pretreatment protocol for post space preparation: irrigattion on with saline (control group), laser-acttivated irrigattion with Er:YAG and Er, Cr:YSGG laser. Finally, each group was subdivided into three subgroups (n=7) depending on the cement used: G-Cem LinkAce (GC, Tokyo, Japan), RelyX U200 (3M ESPE St.Paul, SAD), SpeedCem (Ivoclar Vivadent, Schaan, Liechtenstein). After cementation of FRC posts, specimens were perpendiculary sectioned into 1 mm thin sectiones and push-out test was performed. Statstical anaysis was performed on log- transformed data using factorial ANOVA at level of significance set at 5%. The bond strength values were not affected by the type of post or cement used (p≤0.05). Lower bond strength values were obtained for Er:YAG laser (3.27±1.58 MPa) in comparison to the control group (3.87±1.89 Mpa), (p≤0.05). There was no sta)s)cally significant difference in bond strength of both tested post groups in comparison to control group when Er, Cr:YSGG laser was used (p≤0.05). No sta)s)cally significant difference in bond strength for tested post groups was observed when two erbium lasers were compared (p≤0.05). Conclusions: The bond strength was affected by the type of erbium laser used and Er:YAG laser lowered the bond strength for both prefabricated and individually formed FRC posts.

The objective of this in vitro study was to compare microtensile bond strength of fiber reinforced composite and particulate filler composite to coronal and pulp chamber floor dentin using self- etching adhesive system. Forty human molar teeth, were divided into two experimental groups (n = 20 per group). In the first group, coronal dentin was exposed by cutting of occlusal enamel with the Isomet saw. In the second group, pulp chamber floor dentin was exposed by trepanation, after which chemo- mechanical instrumentation and root canal filling were performed. These two groups were further subdivided into two groups (n=10) according to the type of composite: fiber reinforced composite (everX Posterior, GC, Tokyo, Japan, ) and particulate filler composite (G- aenial Posterior, GC, Tokyo, Japan). A self-etching adhesive system (G-aenial Bond, GC, Tokyo, Japan) was used for all specimens. In the group with exposed coronal dentin, 5 mm high composite blocks were built up with each of the tested composites. In the group with exposed pulp chamber floor dentin, composite resin blocks were built to the level of occlusal surface. Each specimen was serially sectioned to obtain sticks with a cross- sectional area of 1 mm2, and microtensile bond strength test was performed (Figure 1). Statistical analysis was performed using one-way ANOVA test at level of significance set at 5%. Microtensile bond strength values were significantly higher for coronal dentin in comparison to pulp chamber floor dentin (p0.05), (Figure 2). Only the adhesive type of failure was observed in all four experimental groups. Higher microtensile bond strength values were observed for coronal dentin than for pulp chamber floor dentin. Fiber reinforeced and particulate filler composite performed similarly regarding the microtensile bond strength.

Objective: We designed an in vitro study to evaluate the efficiency of an 0.5 vol% hydrogen peroxide-based spray in reducing Coronavirus 229E spread during a conventional dental procedure. Methods: A class III cabinet-like chamber was custom-built, using phantoms for both patient and operator. A suspension of HCoV-229E in artificial saliva having a similar viral load to SARS-CoV-2 asymptomatic patients was inoculated inside the patient’s phantom mouth. A 10 s-lasting dental procedure was performed using an aerosol-generating air-turbine, with or without high-volume evacuation (HVE). The effect of 0.5 vol% H2O2 cooling spray in reducing viral loads was tested. Viral presence on the operator phantom was assessed by Real-Time quantitative PCR on the mask’s outer surface, on the phantom’s forehead, and inside its mouth. Results: When the H2O2 cooling spray was used, as compared to the conventional spray, viral loads were significantly lower on all tested sites, falling below the detection limit. Viral loads did not significantly change in any tested site when HVE was used. Conclusion: The use of 0.5 vol% H2O2 cooling spray by dental handpieces drastically reduced the possibility of coronaviruses spread during aerosol-generating dental procedures. This strategy deserves further consideration among the preventive measures to be adopted during the SARS-CoV-2 pandemic.

Objectives To evaluate the influence of surface treatments of different resin-based composites (RBCs) on S. mutans biofilm formation. Methods 4 RBCs (microhybrid, nanohybrid, nanofilled, bulk-filled) and 6 finishing-polishing (F/P) procedures (open-air light-curing, light-curing against Mylar strip, aluminum oxide discs, one-step rubber point, diamond bur, multi-blade carbide bur) were evaluated. Surface roughness (SR) (n = 5/group), gloss (n = 5/group), scanning electron microscopy morphological analysis (SEM), energy-dispersive X-ray spectrometry (EDS) (n = 3/group), and S. mutans biofilm formation (n = 16/group) were assessed. EDS analysis was repeated after the biofilm assay. A morphological evaluation of S. mutans biofilm was also performed using confocal laser-scanning microscopy (CLSM) (n = 2/group). The data were analyzed using Wilcoxon (SR, gloss) and two-way ANOVA with Tukey as post-hoc tests (EDS, biofilm formation). Results F/P procedures as well as RBCs significantly influenced SR and gloss. While F/P procedures did not significantly influence S. mutans biofilm formation, a significant influence of RBCs on the same parameter was found. Different RBCs showed different surface elemental composition. Both F/P procedures and S. mutans biofilm formation significantly modified this parameter. Conclusions The tested F/P procedures significantly influenced RBCs surface properties but did not significantly affect S. mutans biofilm formation. The significant influence of the different RBCs tested on S. mutans biofilm formation suggests that material characteristics and composition play a greater role than SR. Clinical significance F/P procedures of RBCs may unexpectedly play a minor role compared to that of the restoration material itself in bacterial colonization.

This in vitro study evaluated the influence of chlorhexidine diacetate (CDA) when blended within dentin bonding systems (DBSs) on Streptococcus mutans (S. mutans) biofilm formation. One commercially available 0.2% wt CDA-containing DBS (Peak Universal Bond) and five experimental 0.2% wt CDA-containing DBS formulations (experimental Adper Scotchbond 1XT plus experimental resins, R2, R3, R4, R5) were assessed vs their no-CDA containing counterparts. Twenty-eight DBSs disks were prepared for each group (6.4 mm×1.0 mm) and cured for 80 s at 800 mW/cm2 in a nitrogen atmosphere. A modified Drip-Flow Reactor was used to grow S. mutans biofilms on specimen surfaces for 24 h and adherent, viable biomass was evaluated using a tetrazolium salt assay (MTT). Two specimens from each of the tested materials were processed with LIVE/DEAD stain and observed using laser confocal microscopy (CLSM) while two disks from each group were examined by using scanning electron microscopy (SEM). MTT assay, CLSM and SEM observations showed that CDA addition decreased, increased or did not change S. mutans biofilm formation. The lowest biofilm formation was obtained with Peak Universal Bond and R5 (with and without CDA). It may be concluded that the chemical composition of DBSs determines their ability to promote or hamper biofilm formation. Therefore, CDA addition may be helpful in modulating biofilm formation provided that DBS formulation is tuned and optimized.

Objective: To evaluate in vitro Streptococcus mutans (S. mutans) biofilm formation on the surface of five light-curing experimental dental bonding systems (DBS) with increasing hydrophilicity. The null hypothesis tested was that resin chemical composition and hydrophilicity does not affect S. mutans biofilm formation. METHODS: Five light-curing versions of experimental resin blends with increasing hydrophilicity were investigated (R1, R2, R3, R4 and R5). R1 and R2 contained ethoxylated BisGMA/TEGDMA or BisGMA/TEGDMA, respectively, and were very hydrophobic, were representative of pit-and-fissure bonding agents. R3 was representative of a typical two-step etch-and-rinse adhesive, while R4 and R5 were very hydrophilic resins analogous to self-etching adhesives. Twenty-eight disks were prepared for each resin blend. After a 24h-incubation at 37°C, a multilayer monospecific biofilm of S. mutans was obtained on the surface of each disk. The adherent biomass was determined using the MTT assay and evaluated morphologically with confocal laser scanning microscopy (CLSM) and scanning electron microscopy (SEM). RESULTS: R2 and R3 surfaces showed the highest biofilm formation while R1 and R4 showed a similar intermediate biofilm formation. R5 was more hydrophilic and acidic and was significantly less colonized than all the other resins. A significant quadratic relationship between biofilm formation and hydrophilicity of the resin blends was found. CLSM and SEM evaluation confirmed MTT assay results. CONCLUSIONS: The null hypothesis was rejected since S. mutans biofilm formation was influenced by hydrophilicity, surface acidity and chemical composition of the experimental resins. Further studies using a bioreactor are needed to confirm the results and clarify the role of the single factors.