Dental emergency care in Spain during the state of alarm due to COVID-19 pandemic.

BACKGROUND: The first state of alarm due to COVID-19 in Spain led to limit dental treatment exclusively to emergencies. The objective of the survey was to evaluate the amount and type of emergencies attended during this period, as well as to know how they were solved, and what measures were adopted to carry out dental care in these exceptional circumstances. MATERIAL AND METHODS: This cross-sectional study included 312 Spanish dentists, who fulfilled an online questionnaire with 22 closed questions, divided into five sections regarding to various aspects of professional dental profile and emergency care. Descriptive statistic and Chi-square tests were performed (p<0.05). RESULTS: 75.64% of respondents attended emergencies in person only when required, being dental pain the main emergency (90.38%). Dental emergency care in person involved a prior telephone triage of the patient to identify possible COVID-19 symptoms, as well as protective measures implementation for both, the patient and the dentist, at dental office. CONCLUSIONS: The number of dental emergencies decreased during the state of alarm, being dental pain the main cause of dental assistance via telephone or in person. Triage of patients before scheduling an in-person appointment and protective measures implementation were common features in dental emergency care during the first state of alarm period. Key words:Dental emergencies, COVID-19, state of alarm, survey.

Influence of the adhesive strategy in the sealing ability of resin composite inlays after deep margin elevation.

BACKGROUND: The aim of this study was to determine the influence of the gingival margin position and the adhesive strategy selected to perform deep margin elevation (DME) in marginal sealing of resin composite inlays by a nanoleakage test. MATERIAL AND METHODS: 12 sound third molars were selected and expulsive MOD cavities for inlays were prepared. Experimental groups were established according to gingival margin location (enamel: 1 mm above cemento-enamel junction (CEJ), dentin: 1 mm below CEJ, or DME, and the adhesive strategy used to lute inlays and elevate the gingival margin. Therefore, the six experimental groups were: 1) Enamel + etch-and-rinse adhesive (ERA) Adper Scotchbond 1XT (SB1XT); 2) Dentin + SB1XT; 3) DME + SB1XT; 4) Enamel + self-etching adhesive (SEA) with enamel selective etching Clearfil SE Bond (CSE); 5) Dentin + CSE; 6) DME + CSE. Resin composite inlays were constructed (Gradia Indirect) and all luted with the same resin cement (RelyX ARC). Specimens were submitted to nanoleakage test. Results were analyzed by Kruskal-Wallis and Mann-Whitney U tests with Bonferroni correction (p<0.05). RESULTS: A perfect sealing ability was evidenced for experimental groups with gingival margins on enamel. Similar nanoleakage values were determined when CSE adhesive was applied regardless the gingival margin position. The highest silver nitrate infiltration was detected for elevated margins with the ERA SB1XT. CONCLUSIONS: The SEA Clearfil SE Bond showed higher sealing ability than the ERA Adper Scotchbond 1XT when margins were located on dentin, regardless margin elevation. Gingival margins on enamel together with enamel acid etching provided an excellent sealing with both adhesive systems. Key words:Adhesion, composite inlays, gingival margin, deep margin elevation, marginal seal, nanoleakage test.

Quality of approximal surfaces of posterior restorations in primary molars.

PURPOSE: To evaluate the influence of the restorative material and matrix system on proximal contact tightness and morphological characteristics of class II restorations in primary molars. METHODS: Occluso-mesial cavities in second primary artificial molars were randomly restored using different materials (Filtek Z500 or Filtek Bulk Fill composites or high-viscosity glass ionomer cement Ketac Universal) and different matrix system (Tofflemire, AutoMatrix, matrix band with ring, contoured sectional matrix) (n = 12). Proximal contact tightness was measured using a custom-made device in an Instron 3345, and proximal surface morphology and marginal adaptation were scored after digital scanning. Two-way ANOVA, Tukey and Fischer's exact tests were performed (P < 0.05). RESULTS: Proximal contact tightness values were significantly influenced by the restorative material (P < 0.05), the matrix system (P < 0.001), and their interaction (P < 0.01). Both resin composites showed statistically differences in proximal shape according to the matrix used to restore and exhibited overhanging margins. Ketac Universal restorations showed similar morphology and gaps on the margins regardless of the matrix system. CONCLUSIONS: Overall, both composite restorations achieved tighter proximal contact than those restored with the high-viscosity glass ionomer cement. None of the matrix systems tested provided a convex seamless proximal morphology.

Effect of a single-component ceramic conditioner on shear bond strength of precoated brackets to different CAD/CAM materials.

OBJECTIVES: To compare the shear bond strength (SBS) of the CAD/CAM material-bracket interface using three surface treatments: following manufacturers' instructions (MI), Monobond Etch & Prime (MEP) and 9.6% hydrofluoric acid plus silane (9.6% HF), after 24 h of water storage (24 h) and 10,000 cycles of thermocycling (TC). MATERIALS AND METHODS: A total of 126 crowns with four identical buccal surfaces were fabricated using seven different CAD/CAM materials: CEREC Blocs unglazed (CBU), CEREC Blocs glazed (CBG), IPS Empress CAD (EMP), IPS e.max CAD (EMA), VITA SUPRINITY PC (SUP), inCoris TZI (TZI) and VITA ENAMIC (ENA). A total of 504 APC Flash-Free (APC FF)-precoated brackets were bonded applying three surface treatments: (1) MI; (2) MEP and (3) 9.6% HF. SBS was performed after 24 h and TC. Results were analyzed by Kruskal-Wallis and Mann-Whitney U tests (p < 0.05). RESULTS: MEP conditioning yielded lower SBS results compared with MI and 9.6% HF for CBG (24 h and TC) and EMA (TC) materials. EMP conditioning with MEP after 24 h obtained lower SBS values compared with MI; however, after TC, SBS was similar to MI group and higher than with 9.6% HF. After TC for TZI ceramic, MI protocol (sandblasting) obtained higher SBS scores than MEP, but similar than 9.6% HF. Treatment of ENA with MI and MEP produced higher results than 9.6% HF after TC. SBS results were similar for CBU and SUP, regardless of the treatment. CONCLUSIONS: Although each CAD/CAM material requires specific surface treatment to obtain the highest SBS of APC FF brackets, the treatment with MEP is a valid orthodontic alternative for most of the materials tested. TC significantly decreased SBS for most of the materials. CLINICAL RELEVANCE: MEP can be considered a valid and promising product to condition most of the CAD/CAM ceramics evaluated for APC FF bracket bonding purposes, allowing a faster and safer procedure.

Shear bond strength of a flash-free orthodontic adhesive system after thermal aging procedure.

In this article by Carlos and colleagues (J Clin Exp Dent. 2019 Feb 1;11(2):e154-61), there is an error in the Material and Methods of the abstract. The correct Material and Methods of the abstract is: Material and Methods: A total of 120 human premolars were randomly divided into two groups (n=60) according to the orthodontic adhesive used: APC Flash-Free Adhesive Coated Appliance System (APC FF) or Transbond PLUS Color Change Adhesive (TP), as control. A SBS test was performed and ARI value for each specimen was also assessed. Results were analyzed by two-way ANOVA and Tukey's Chi-square test (p<0.05).

Shear bond strength of a flash-free orthodontic adhesive system after thermal aging procedure.

BACKGROUND: The aim of this study was to compare the shear bond strength (SBS) of a flash-free and precoated orthodontic adhesive with a compomer orthodontic adhesive before and after thermocycling. The adhesive remnant index (ARI) was also determined for both adhesives. MATERIAL AND METHODS: The adhesive remnant index (ARI) was also determined for both adhesives. Material and Methods: A total of 120 human premolars were randomly divided into two groups (n=60) according to the orthodontic adhesive used: APC Flash-Free Adhesive Coated Appliance System (APC FF) or Transbond PLUS Color Change Adhesive (TP), as control. A SBS test was performed and ARI value for each specimen was also assessed. Results were analyzed by two-way ANOVA and Tukey's Chi-square test (p<0.05). RESULTS: SBS values were significantly influenced by thermocycling (p<0.01). Neither the orthodontic adhesive nor the interaction between adhesive and thermocycling statistically affected SBS results (p>0.05). CONCLUSIONS: APC FF and TP showed similar bond strength results. Thermocycling induced a significant decrease in SBS values for the two adhesives tested, without differences between 10,000 and 20,000 thermal cycles. Moreover, APC FF left less adhesive remnants on the enamel compared to TP. Key words:APC Flash-Free, APC cement, aging, orthodontics, resin cements.

Repair bond strength and nanoleakage of artificially aged CAD-CAM composite resin.

STATEMENT OF PROBLEM: The polymerization of computer-aided design and computer-aided manufacturing (CAD-CAM) composite resins during their manufacture enhances their physical properties and biocompatibility but might compromise their reparability. PURPOSE: The purpose of this in vitro study was to determine the microtensile bond strength and nanoleakage (NL) of aged LAVA Ultimate (LU) CAD-CAM composite resin after different repair protocols. MATERIAL AND METHODS: Fifty-eight LU miniblocks were prepared, thermocycled (10000 cycles, 5°C to 55°C), and assigned to 10 surface pretreatment and bonding protocols: (1) tribochemical silica coating (CoJet, CoJet Sand; 3M ESPE)+Scotchbond Universal Adhesive (SBU; 3M ESPE); (2) CoJet+silane (SI, ESPE Sil; 3M ESPE)+Adper Scotchbond 1 XT Adhesive (XT; 3M ESPE); (3) CoJet+10-methacryloyloxydecyl dihydrogen phosphate-based silane (MO; Monobond Plus; Ivoclar Vivadent AG)+XT; (4) CoJet+XT; (5) 30-µm alumina airborne-particle abrasion (AL)+SBU; (6) AL+SI+XT; (7) AL+MO+XT; (8) AL+XT; (9) no pretreatment+SBU; and (10) no pretreatment+XT. All blocks were repaired using the Filtek Supreme XTE (3M ESPE) composite resin. Stick-shaped specimens (0.9×0.9 mm) were obtained and submitted to microtensile bond strength (µTBS) and %NL testing after 24 hours. µTBS data were analyzed with 1-way ANOVA, followed by the Tukey post hoc test, and NL data with nonparametric Kruskal-Wallis and Dunn tests (α=.05). RESULTS: For µTBS, CoJet, and AL pretreatments showed significantly higher mean µTBS, especially when used together with SBU. No pretreatment+XT yielded the lowest mean µTBS. For NL, marginal sealing improved significantly after the use of SBU regardless of the surface treatment. This improvement was only statistically different after tribochemical silica coating. CONCLUSIONS: Airborne-particle abrasion with alumina particles, silica coated or not, together with the application of SBU resulted in the highest mean µTBS. The lowest %NL was recorded when aged LU blocks were repaired using SBU.

Effect of indirect composite treatment microtensile bond strength of self-adhesive resin cements.

BACKGROUND: No specific indications about the pre-treatment of indirect composite restorations is provided by the manufacturers of most self-adhesive resin cements. The potential effect of silane treatment to the bond strength of the complete tooth/indirect restoration complex is not available.The aim of this study was to determine the contribution of different surface treatments on microtensile bond strength of composite overlays to dentin using several self-adhesive resin cements and a total-etch one. MATERIAL AND METHODS: Composite overlays were fabricated and bonding surfaces were airborne-particle abraded and randomly assigned to two different surface treatments: no treatment or silane application (RelyX Ceramic Primer) followed by an adhesive (Adper Scotchbond 1 XT). Composite overlays were luted to flat dentin surfaces using the following self-adhesive resin cements: RelyX Unicem, G-Cem, Speedcem, Maxcem Elite or Smartcem2, and the total-etch resin cement RelyX ARC. After 24 h, bonded specimens were cut into sticks 1 mm thick and stressed in tension until failure. Two-way ANOVA and SNK tests were applied at α=0.05. RESULTS: Bond strength values were significantly influenced by the resin cement used (p<0.001). However, composite surface treatment and the interaction between the resin cement applied and surface treatment did not significantly affect dentin bond strength (p>0.05). All self-adhesive resin cements showed lower bond strength values than the total-etch RelyX ARC. Among self-adhesive resin cements, RelyX Unicem and G-Cem attained statistically higher bond strength values. Smartcem2 and Maxcem Elite exhibited 80-90% of pre-test failures. CONCLUSIONS: The silane and adhesive application after indirect resin composite sandblasting did not improve the bond strength of dentin-composite overlay complex. Selection of the resin cement seems to be a more relevant factor when bonding indirect composites to dentin than its surface treatment. KEY WORDS: Bond strength, self-adhesive cement, silane, dentin, indirect composite.

Influence of repair procedure on composite-to-composite microtensile bond strength.

PURPOSE: To investigate the effect of different repair procedures and storage time on microtensile bond strength (µTBS) of a resin composite to an older one from a simulated previous restoration. METHODS: Composite disks were made by layering 2 mm-thick increments of a nanohybrid composite (Grandio) shade A1 in a Teflon mold (4 x 8 mm). Afterwards, they were light-cured and stored (37 degrees C/7 days) in a saline solution. Specimens were randomly divided into groups according to the surface treatment applied: (1) Composite surface was roughened with a bur (Cimara) and Solobond Plus adhesive was applied; (2) Sandblasting with 27 µm aluminum oxide particles (KaVo Rondoflex), and adhesive application; (3) Air-abrasion with 30 µm alumina particles coated with silica (CoJet Sand), silane (Monobond-S) and adhesive application; (4) Negative control group with only adhesive application. Afterwards, Grandio composite (shade A3.5) was packed incrementally on the treated surface obtaining another disk (4 x 8 mm). Repaired blocks were stored (24 hours or 6 months) and afterwards µTBS test was performed and failure mode was evaluated. Also, beams obtained from 8 mm-high composite blocks without any surface treatment were immediately submitted to µTBS test to determine Grandio composite cohesive bond strength (positive control group). Data were analyzed using ANOVA and Tukey's test (P < 0.05). RESULTS: The repair procedure affected µTBS values (P < 0.001) while neither storage time nor interactions did (P > 0.05). All repair procedures achieved bond strength values higher than the negative control group but they did not reach the composite's cohesive bond strength. The overall conclusion was that an increased superficial roughness by means of a bur, silica coating or alumina sandblasting improved µTBS of the repaired composite and bond strength remained stable after 6 months.

Microhardness of different resin cement shades inside the root canal.

OBJECTIVES: To compare microhardness along the root canal post space of two resin cements in different shades and a dual-cure resin core material. STUDY DESIGN: Root canals of 21 bovine incisors were prepared for post space. Translucent posts (X∘Post, Dentsply DeTrey) were luted using one the following resin luting agent: Calibra (Dentsply DeTrey) in Translucent, Medium and Opaque shades, RelyX Unicem (3M ESPE) in Translucent, A2 and A3 shades and the dual-cure resin core material Core∘X flow. All materials were applied according to manufacturers' instructions and were all photopolymerized (Bluephase LED unit, Ivoclar Vivadent, 40s). After 24 hours, roots were transversally cut into 9 slices 1 mm thick from the coronal to apical extremes, three corresponding to each root third. Then, VHNs were recorded (100gf, 30 s) on the resin luting materials along the adhesive interface in all sections. Data were analyzed by two-way ANOVA and SNK tests (α=0.05). RESULTS: A significant influence on microhardness of resin luting material in their respective shades (p<0.0001), root third (p<0.0001) and interactions between them was detected (p<0.0001). RelyX Unicem cement showed the highest microhardness values and Calibra the lowest, regardless of the shade selected. All resin luting materials tested exhibited a significantly higher microhardness in the cervical third. CONCLUSIONS: Microhardness of resin luting agents tested inside the canal is dependent on material brand and resin cement shade seems to be a less relevant factor. Microhardness decreased along the root canal, regardless of the shade selected.

Curing effectiveness of resin composites at different exposure timesusing LED and halogen units

Objective: To compare the polymerization effectiveness of two resin composites cured with a quartz tungsten halogen(QTH) lamp or a light emitting diodes (LED) unit. Study design: Filtek Z250 (3M ESPE) and Spectrum TPH (DentsplyDeTrey) resin composites were placed in 9 mm deep and 4 mm wide metallic molds and cured using the QTH light Hilux200 (Benlioglu) or the LED unit Smartlite IQ (Dentsply DeTrey) for 20 or 40 s (three specimens per group). Measurementof depth of cure was carried out by means of a scraping technique, according to ISO 4049. The microhardness measurementswere performed using a calibrated Vickers indenter (100 g load, 30 s) at depths of 0.5, 1.5, 2.5, 3.5, 4.5 and 5.5 mm fromthe top of the composite in the same specimens. Results were analyzed by ANOVA, Student´s t and Student-Newman-Keulstests (p<0.05). Results: Filtek Z250 exhibited higher depth of cure and Vickers microhardness values than Spectrum TPHunder each experimental condition evaluated. Depth of cure and microhardness were not affected by the curing light used.However, hardness values were influenced by the interaction between curing light and exposure time. Specimens irradiatedfor 20 s exhibited higher microhardness values when the LED curing light was used. Exposure time had no influence on themicrohardness values for depths from 0.5 to 2.5 mm. At higher depths, irradiation for 40 s produced greater microhardnessvalues. Conclusions: Curing effectiveness of resin composite is not only dependent on the curing light unit. Results varygreatly with composite brand, thickness of the resin composite and the duration of the exposure (AU)

Curing effectiveness of resin composites at different exposure times using LED and halogen units.

OBJECTIVE: To compare the polymerization effectiveness of two resin composites cured with a quartz tungsten halogen (QTH) lamp or a light emitting diodes (LED) unit. STUDY DESIGN: Filtek Z250 (3M ESPE) and Spectrum TPH (Dentsply DeTrey) resin composites were placed in 9 mm deep and 4 mm wide metallic molds and cured using the QTH light Hilux 200 (Benlioglu) or the LED unit Smartlite IQ (Dentsply DeTrey) for 20 or 40 s (three specimens per group). Measurement of depth of cure was carried out by means of a scraping technique, according to ISO 4049. The microhardness measurements were performed using a calibrated Vickers indenter (100 g load, 30 s) at depths of 0.5, 1.5, 2.5, 3.5, 4.5 and 5.5 mm from the top of the composite in the same specimens. Results were analyzed by ANOVA, Student's t and Student-Newman-Keuls tests (p<0.05). RESULTS: Filtek Z250 exhibited higher depth of cure and Vickers microhardness values than Spectrum TPH under each experimental condition evaluated. Depth of cure and microhardness were not affected by the curing light used. However, hardness values were influenced by the interaction between curing light and exposure time. Specimens irradiated for 20 s exhibited higher microhardness values when the LED curing light was used. Exposure time had no influence on the microhardness values for depths from 0.5 to 2.5 mm. At higher depths, irradiation for 40 s produced greater microhardness values. CONCLUSIONS: Curing effectiveness of resin composite is not only dependent on the curing light unit. Results vary greatly with composite brand, thickness of the resin composite and the duration of the exposure.