Evaluation of the ceramic laminate veneer-tooth interface after different resin cement excess removal techniques.

OBJECTIVES: To compare, in vitro, resin cement excess removal techniques at the veneer-tooth interface. MATERIALS AND METHODS: Anterior human teeth were restored with ceramic veneers and randomly divided according to the following techniques (n = 10): removal of excess resin cement with brush and dental floss, followed by light-curing with Valo (Group 1) or Elipar (Group 2) for 1 min and 40 s; tack-curing with Valo (Group 3) or Elipar (Group 4) for 1 s; and tack-curing with Valo (Group 5) or Elipar (Group 6) for 5 s. The tack-curing was followed by removal of excess with probe and dental floss and light-curing for 1 min and 40 s. The area of excess resin cement (mm2) was measured in micro-CT images using AutoCAD program. The failures at the cervical margin in the X, Y, and Z axes (µm) of greater value were measured using the DataViewer program. The specimens were submitted to microleakage with 2% basic fuchsin. RESULTS: According to the Kruskal-Wallis and multiple comparison test, the highest area of excess resin cement was found in Group 1 (5.06 mm2), which did not differ statistically from Groups 2 (3.70 mm2) and 5 (2.19 mm2). Groups 2, 3 (1.73 mm2), 4 (1.14 mm2), and 5 (2.18 mm2) did not differ statistically. Group 6 (0.77 mm2) obtained the lowest value, which did not differ statistically from Groups 3 and 4. According to the Kruskal-Wallis and Dunn test, there was no significant difference in failures in X (p = 0.981), Y (p = 0.860), and Z (p = 0.638) axes and no significant difference in microleakage (p = 0.203) among the groups. CONCLUSIONS: Tack-curing for 1 s or 5 s, followed by removal of excess resin cement using a probe and a dental floss, tended to result in a lower amount of excess material around the margin. CLINICAL RELEVANCE: The technique used for resin cement excess removal influences the amount of excess leaved at the veneer-tooth interface. Tack-curing for 1 s or 5 s is recommended to mitigate the excess resin cement.

Experimental study on the mechanical properties of desert sand improved by the combination of additives and bio-cement.

Bio-cement is a green and energy-saving building material that has attracted much attention in the field of ecological environment and geotechnical engineering in recent years. The aim of this study is to investigate the use of bio-cement (enzyme-induced calcium carbonate precipitation-EICP) in combination with admixtures for the improvement of desert sands, which can effectively improve the mechanical properties of desert sands and is particularly suitable for sand-rich countries. In addition, the suitability of tap water in bio-cement was elucidated and the optimum ratio of each influencing factor when tap water is used as a solvent was derived. The results showed that peak values of unconfined compressive strength (maximum increase of about 130 times), shear strength (increase of 27.09%), calcium carbonate precipitation value (increase of about 4.39 times), and permeability (decrease of about 93.72 times) were obtained in the specimens modified by EICP combined with admixture as compared to the specimens modified by EICP only. The incorporation of skimmed milk powder, though significantly increasing the strength, is not conducive to cost control. The microscopic tests show that the incorporation of admixtures can provide nucleation sites for EICP, thus improving the properties of desert sand. This work can provide new research ideas for cross-fertilization between the disciplines of bio-engineering, ecology, and civil engineering.

Physicochemical and mechanical properties of preheated composite resins for luting ceramic laminates.

This study analyzed and compared the physicochemical and mechanical properties of preheated resin composite with light-cured resin cement for luting indirect restorations. 210 specimens of resin cement/resin composite were prepared according to preheating treatment heated (Htd) or not (NHtd). Light-cured resin cement (Variolink Veneer, Ivoclar), and resin composite (Microhybrid-Z100, 3 M; Nanohybrid-Empress direct, Ivoclar; and Bulk fill-Filtek One, 3 M) were used (n = 10). Resin cement specimens were not preheated. The response variables were (n = 10): film thickness, microhardness, liquid sorption and solubility. Data were analyzed by 2-way ANOVA and Tukey HSD post-test (α = 0.05). Bulk fill NHtd resin had the highest film thickness values (p < 0.001). Microhybrid and nanohybrid Htd resins had the smallest thicknesses and did not differ from the cement (p > 0.05). The highest microhardness values were found for Bulk fill NHtd and Bulk fill Htd resins. The nanohybrid and microhybrid Htd resins showed the lowest microhardness values, with no difference in cement (p > 0.05). For liquid sorption, there was no significant difference between the groups (p = 0.1941). The microhybrid Htd resin showed higher solubility values than the other materials (p = 0.0023), but it did not differ statistically from resin cement (p > 0.05). Preheating composite resins reduced the film thickness. After heating, nanohybrid and Bulk fill resins retained stable microhardness, sorption, and solubility values.

Effect of preheating and ultrasound application of resin-based luting agents on the failure load of a lithium disilicate glass-ceramic.

PURPOSE: To assess the effect of preheating resin-based materials and ultrasound application on the failure load of a lithium disilicate glass-ceramic. MATERIALS AND METHODS: Ninety ceramic specimens were produced (14×12×1.0 mm) and divided into 9 groups (n = 10) to be bonded to a dentin analog (Nema G10) with light-cured luting agent (LC), flowable resin composite (FL), and supra-nano filled resin composite (SN), as follows: LC/R - LC at room temperature; LC/P - preheated LC; LC/P/U - preheated LC and Ultrasound; FL/R - FL at room temperature; FL/P - preheated FL; FL/P/U - preheated FL and Ultrasound; SN/R - SN at room temperature; SN/P - preheated SN; SN/P/U - preheated SN and Ultrasound. The failure load test was performed in a universal testing machine with the aid of acoustic detection. The data was analyzed with two-way ANOVA (for failure load) and Weibull statistics (Weibull modulus - m and characteristic strength, based on 95% confidence intervals - CI). RESULTS: The analyses of failure load revealed no statistically significant difference among groups considering the type of luting agent (P = 0.075; F = 2,673), the application method (P = 0.772; F = 2,259), and the interaction between them (P = 0.297; F = 1,248). The characteristic strength did not show differences among groups (95% CI). The m, which indicates structural reliability, showed lower values for SN/P/U and SN/P, with a difference from other selected groups (95% CI). CONCLUSION: Preheating of resin-based materials and ultrasound application did not affect the failure load of lithium disilicate glass-ceramic. Lower reliability was observed with supra-nano filled resin composite.

The distribution of marginal excess cement of implant-supported vented and non-vented zirconia crowns with and without cleaning procedures.

PURPOSE: To investigate the distribution of marginal excess cement in vented and non-vented crowns and evaluate the effect of clinical cleaning procedures on the reduction of excess cement. MATERIALS AND METHODS: Forty models with implant analogs in the position of the right maxillary first molar were divided into four groups (n = 10/group, vented/non-vented crowns with or without cleaning procedures). The abutment finish lines were placed 1 mm below the artificial gingiva buccally, mesially, and distally and at the gingival level palatally. A standardized amount (20 mg) of resin cement was applied in a thin layer to the intaglio surface of zirconia vented and non-vented crowns. The excess cement was removed by a dental explorer in groups with cleaning procedures. The distribution (area and depth) of the marginal excess cement was measured at each quadrant (buccal, mesial, palatal, and distal) for all study samples. The data were analyzed using descriptive and analytical statistics (ɑ = 0.05). RESULTS: The area and depth values of the excess cement in each quadrant in the vented group were significantly smaller than that in the non-vented group, both with and without cleaning (p < 0.001). Cleaning procedures significantly reduced the area of excess cement in both vented and non-vented groups (all, p < 0.001 except for p < 0.05 at the buccal aspect of the vented group). The depth of excess cement in the vented group was significantly decreased with cleaning in the buccal quadrant compared with that without cleaning (p < 0.01). However, the depth of excess cement of the non-vented group was significantly increased with cleaning in all quadrants compared with that without cleaning (all, p < 0.001 except for p < 0.05 at the distal aspect). CONCLUSIONS: Crown venting significantly reduced the area and depth of the marginal excess cement in vitro. Cleaning procedure with a dental explorer significantly reduced the area of marginal excess cement in vitro; however, the excess cement can be pushed deeper in the non-vented group.

Technique for cementing screwmentable implant crowns to prevent misalignment.

The purpose of this article is to describe a technique to accurately cement implant crowns on an abutment extraorally and prevent misalignment that might change the desired position of the crown on the abutment when delivered. An implant-retained crown was tried-in and occlusal and interproximal contacts were adjusted for delivery. The cementation verification aid was fabricated using a polyvinylsiloxane bite registration material (Blu Mousse) to cement the crown onto the abutment extraorally to ensure proper alignment of the crown on the abutment. Cementation of the prosthesis occurred with no adjustments required to the interproximal or occlusal contacts during final delivery. This article provides a technique that aims to increase accuracy in the placement of the crown on the abutment when cementing screwmentable crowns.

Minimizing excess cement around implant restorations: an in vitro study of cementation techniques.

Excess cement around cement-retained implant crowns is associated with a higher incidence of peri-implantitis, but there are limited data to indicate which cement application technique minimizes excess cement. The purpose of this in vitro study was to evaluate the amount of excess cement that resulted from different cement application techniques. Fifty identical titanium custom abutments and monolithic zirconia crowns were digitally designed and milled in the shape of a maxillary first molar. Ten crowns were cemented by applying temporary cement only to the intaglio coronal surface of the crown; these specimens were used as a control group to determine the amount of cement to be used in all other groups. Four different cement application methods were evaluated (n = 10): wall layer technique, in which cement was brushed on the intaglio axial walls of the crown; precementation technique, in which cement was applied to the intaglio coronal aspect of the crown, and the crown was precemented on an abutment replica, quickly removed, and then repositioned on the milled abutment; rim application, in which cement was applied to the cervical marginal rim of the crown; and increased cement space, in which the cement space was increased to 60 µm (compared with 40 µm in other groups) and cement was brushed on the intaglio coronal surface. Digital photographs of the cemented crowns were taken, and image editing software was used to measure the displacement of excess cement, that is, the distance that it traveled below the finish line on the mesial, distal, buccal, and lingual surfaces. Excess cement was then removed from each specimen and weighed. An analysis of variance test was used to evaluate the difference among groups, and each pair of groups was compared with the t test. Compared with all of the other experimental groups, specimens cemented with the wall layer technique showed a significantly smaller amount of cement excess in terms of both the distance traveled and weight (P < 0.05). Based on the findings, the wall layer cementation technique, in which cement is brushed on the intaglio walls of the crown, is recommended to reduce excess cement around implant crowns.

Effect of irrigation acid solutions on cleaning and bond strength to post-space dentin.

This study evaluated the effects of irrigating solutions containing 5% boric acid + 1% citric acid or 1% peracetic acid + high concentration hydrogen peroxide on root cleaning and bond strength of cementation systems after 24 h and 6 months of glass fiber post cementation. One hundred and twenty roots were endodontically treated. The specimens were randomized into one of four treatments (n = 10): DW (distilled water); NaOCl2.5% + EDTA17% (2.5% sodium hypochlorite solution + 17% EDTA); PA1% + HP (1% peracetic acid solution + high concentration of hydrogen peroxide); BA5% + CA1% (5% boric acid associated with 1% citric acid). The cleaning efficacy in the cervical, middle, and apical thirds of the post-space, and the push-out bond strength at 24 h and 6 months after post cementation were evaluated by Kruskal-Wallis and two-way ANOVA tests, respectively. BA5% + CA1% showed statistically significantly superior cleaning efficacy compared to the other solutions. This irrigation protocol also resulted in higher bond strength at 24 h and 6 months, regardless of the root third considered, and this was statistically significantly higher than those seen for DW and PA1% + HP. For BA5% + CA1% irrigation protocol, type 1 adhesive failure was the most prevalent. Post-space irrigation with BA5% + CA1% provided both higher cleaning efficacy and better bond strength.

Clinical outcomes of tooth-supported monolithic zirconia vs. porcelain-veneered zirconia fixed dental prosthesis, with an additional focus on the cement type: a systematic review and meta-analysis.

PURPOSE: To compare the failure rates and the prevalence of technical complications between full-coverage tooth-supported monolithic zirconia (MZ) and porcelain-veneered zirconia (PVZ) fixed dental prosthesis, based on a systematic literature review. METHODS: An electronic search was performed in three databases, supplemented by hand searching. Several statistical methods were used. RESULTS: Seventy-four publications reported 6370 restorations (4264 PVZ; 2106 MZ; 8200 abutment teeth; 3549 patients), followed up until 152 months. A total of 216 prostheses failed, and survival was statistically significant different between groups. PVZ had higher occurrence of complications than MZ; the difference was especially greater for either minor or major chipping. The difference in prevalence of either minor or major chipping was statistically significant for PVZ prostheses between cementation with glass ionomer and adhesive resin cement (higher), adhesive resin and resin-modified glass ionomer cement (RMGIC, higher), and between RMGIC (higher) and glass ionomer cement. For MZ the difference was significant only for minor chipping between RMGIC (higher) and adhesive resin cement. Abutment teeth to PVZ prostheses more often lost vitality. Decementation was not observed with RMGIC. Air abrasion did not seem to clinically decrease the decementation risk. The 5-year difference in the occurrence of minor or major chipping between MZ and PVZ prostheses was statistically significant, but nor for catastrophic fracture. CONCLUSION: Tooth-supported PVZ prostheses present higher failure and complication rates than MZ prosthesis. The difference in complications is striking when it comes to chipping. CLINICAL RELEVANCE: Awareness of the outcome differences between different types of zirconia prostheses is important for clinical practice.

Impact of polyethylene glenoid cementation technique on cement mantle integrity and stability after cyclic loading: a computed tomography and biomechanical study.

BACKGROUND: There are no generally accepted guidelines for polyethylene (PE) glenoid component cementation techniques. In particular, it is not known whether the backside of a PE glenoid should be fully or partially cemented-or not cemented at all. We hypothesized that cementing techniques would have an impact on cement mantle volume and integrity, as well as biomechanical stability, measured as micromotion under cyclic loading. METHODS: To address our hypothesis, 3 different cementation techniques using a single 2-peg PE glenoid design with polyurethane foam were compared regarding (1) the quality and quantity of the cement mantle and (2) biomechanical stability after cyclic loading in vitro. Eight identically cemented glenoids per group were used. Group A underwent cement application only into the peg holes, group B received additional complete cement mantle application on the backside of the glenoid, and group C received the same treatment as group B but with additional standardized drill holes in the surface of the glenoid bone for extra cement interdigitation. All glenoids underwent cyclic edge loading by 105 cycles according to ASTM F2028-14. Before and after loading, cement mantle evaluation was performed by XtremeCT and biomechanical strength and loosening were evaluated by measuring the relative motion of the implants. RESULTS: The cement mantle at the back of the implant was incomplete in group A as compared with groups B and C, in which the complete PE backside was covered with a homogeneous cement mantle. The cement mantle was thickest in group C, followed by group B (P = .006) and group A (P < .001). We did not detect any breakage of the cement mantle in any of the 3 groups after testing. Primary stability during cyclic loading was similar in all groups after the "running-in" phase (up to 4000 cycles). Gross loosening did not occur in any implant. CONCLUSIONS: Coverage of the PE glenoid with cement was reproducible in the fully cemented groups (ie, groups B and C) as compared with relevant cement defects in group A. The addition of cement to the back of the PE glenoid and additional drill holes in the glenoid surface did not improve primary stability in the tested setting.

Long-Term Outcomes of Cementing Highly Cross-Linked Polyethylene Liners Into Well-Fixed Acetabular Shells in Revision Total Hip Arthroplasty.

BACKGROUND: Cementing a new liner into a secure, well-positioned metallic shell can be a less-invasive strategy in revision total hip arthroplasty (THA). This study aimed to report the mean 14-year outcomes of cementing highly cross-linked polyethylene (XLPE) liners into well-fixed acetabular shells in revision THAs. METHODS: This study reviewed a single-surgeon series of cementing XLPE liners into well-fixed acetabular components. Of the 52 hips (51 patients) evaluated, 48 hips (47 patients) that satisfied a minimum follow-up of 10 years were included. The Harris Hip score was used for clinical evaluation. Final hip radiographs were used to determine the extent of acetabular osteolysis and stability of the components. The mean age at index operation was 53 years (range, 32 to 72). The mean follow-up duration was 14 years (range, 10 to 18). RESULTS: The mean Harris Hip score improved from 58 points (range, 23-81) preoperatively to 91 points (range, 45-100) at the final evaluation (P < .001). A total of 3 acetabular rerevisions were performed, all for aseptic loosening of the outer shell. One postoperative dislocation occurred, but it was successfully treated with a closed reduction. Final radiographs showed a significant reduction in acetabular osteolysis (P < .001). Implant survivorship free from any rerevision was 93.3% (95% confidence interval, 85.9-100%) at 14 years. CONCLUSION: Cementing an XLPE liner into a well-fixed acetabular shell in revision THA demonstrated excellent clinical and radiographic outcomes at a mean of 14 years postoperatively. This technique could be a safe and durable option in the absence of XLPE liners compatible with preimplanted shells.

Isolated Liner Exchange in Total Hip Arthroplasty at a Mean of 13 Years of Follow-up: Does Fixation Technique Matter?

BACKGROUND: Isolated liner exchange is an option to address polyethylene wear after total hip arthroplasty (THA). The liner can be fixed with either the original locking mechanism or cemented into the acetabular cup. Whether the method used for liner fixation has any bearing on the outcomes in the first and second decade after surgery is still unclear. METHODS: Data for all patients who had undergone isolated liner exchange surgery in our institution between April 1995 and January 2015 were retrieved. Patients were classified according to the type of polyethylene liner (conventional or highly crosslinked polyethylene) and the locking mechanism used (original locking mechanism or cemented). Survivorship and revision rates were compared among different subgroups. A total of 118 isolated liner exchanges were performed and patients had a mean duration of follow-up of 13 years (range, 5 to 25). RESULTS: Overall estimated mean survivorship was 17 years. Use of highly crosslinked polyethylene (HXLPE) had a lower re-revision rate compared to conventional liners (10.5 versus 46.9%) (P < .001). The re-revision rate of exchanges using HXLPE was not affected by the type of fixation (original locking mechanism 11.1 versus cement 10.0%, P = .868). Conversely, using the original locking mechanism with a conventional liner had a higher re-revision rate compared to cemented conventional liners (58.3 versus 12.5%) (P = .024). CONCLUSION: HXLPE liners should be used in insert exchange surgery whenever possible. Re-revision rate of exchanges using HXLPE was not affected by the fixation technique used. Cementing an insert into an acetabular component is associated with good survivorship at a mean of 13 years follow-up.

Etch-and-rinse versus self-etch strategy of a universal adhesive in different application methods at the bonding interface of fiber post cementation.

OBJECTIVE: To evaluate the effect of etch-and-rinse (ER) versus self-etch (SE) strategies of a universal adhesive applied with a manual brush (MB) or rotary brush (RB) on the bonding interface of fiber post cementation. METHODS: Forty bovine incisor roots were prepared and divided into four groups according to the methods of application and strategy of universal adhesive use (MB-ER, RB-ER, MB-SE and RB-SE). After 6 months, specimens from different thirds of the post space were evaluated of push-out strength, analysis of adhesive failure patterns, and extent of tags. RESULTS: The RB-ER and RB-SE groups showed the highest bond strength values in the cervical and middle thirds of the post space. Cohesive adhesive failure had the highest incidence in the different thirds of the post space in the ER strategy, regardless of the adhesive application method. The RB-ER group showed the highest tag extensions. CONCLUSIONS: The protocols of universal adhesive application with RB provided the greater bond strength, but only the ER strategy favored the formation of a greater extension of tags at the adhesive interface. CLINICAL SIGNIFICANCE: The application of universal adhesive with RB into the post space increases the strength of the post-cemented fiber bond.

A sustainable route for the recovery of metals from waste printed circuit boards using methanesulfonic acid.

The rapid increase in electronic waste (e-waste) generation and its unsustainable management pose a threat to the environment and human well-being. However, various valuable metals are present in e-waste, which makes it a potential secondary source to recover metals. Therefore, in the present study, efforts were made to recover valuable metals (Cu, Zn, and Ni) from waste printed circuit boards (WPCB) of computers using methanesulfonic acid (MSA). MSA is contemplated as a biodegradable green solvent and has a high solubility for various metals. The effect of various process parameters (MSA concentration, H2O2 concentration, stirring speed, liquid to solid ratio, time, and temperature) was investigated on metal extraction to optimize the process. At the optimized process conditions, 100% extraction of Cu and Zn was achieved, while Ni extraction was around 90%. The kinetic study for metal extraction was performed using a shrinking core model and findings showed that MSA-aided metal extraction is a diffusion-controlled process. Activation energies were found to be 9.35, 10.89, and 18.86 kJ/mol for Cu, Zn, and Ni extraction, respectively. Furthermore, the individual recovery of Cu and Zn was achieved using the combination of cementation and electrowinning, which resulted in 99.9% purity of Cu and Zn. The current study proposes a sustainable solution for the selective recovery of Cu and Zn from WPCB.

Printed abutment model to limit residual cement: A dental technique.

Preventing retained cement around implant-retained crowns is crucial for the long-term health and success of the implant. Residual subgingival cement is strongly associated with peri-mucositis and can lead to peri-implantitis. This clinical technique utilizes a 3D printed model of a custom abutment to seat the implant crown on before cementing intra-orally to extrude excess cement. The technique aims to limit the amount of retained cement at the crown-abutment margin and also takes into consideration the cement space already designed into the crown-abutment complex.

Effect of Vent Hole and Cement Type on Fracture Resistance of CAD-CAM Monolithic Zirconia Crowns.

PURPOSE: To assess the fracture resistance of monolithic zirconia crowns cemented with different types of cement on cement-retained implant abutments. MATERIALS AND METHODS: Forty implant analogs were positioned in acrylic resin blocks, and cement-retained straight implant abutments were fastened to the analogs. Crowns were designed with/without occlusal vent holes and produced from monolithic zirconia blocks by the CAD-CAM technique. The two crown types were divided into two groups and cemented with resin and zinc-polycarboxylate cement under 5 kg weight. A universal testing machine applied compressive forces to the crowns until fracture. Fracture resistance values were analyzed using two-way ANOVA and the independent samples t-test with statistical significance set at p < 0.05. RESULTS: According to the two-way ANOVA results, although the crown design did not have a significant effect on fracture resistance (1417.65 ± 337.39 N, 1565.16 ± 517.12 N; crowns with and without vent holes, respectively), the main effect of the cement variable on the fracture resistance was significant. Zinc-polycarboxylate cement (1680.1 ± 375.23 N) showed higher fracture resistance than resin cement (1302.71 ± 420.64 N) in the crowns designed with vent holes (p < 0.005). CONCLUSION: The use of cement-retained implant-supported monolithic zirconia crowns with an occlusal vent hole is safe, and zinc-polycarboxylate cement use may be an appropriate choice for cementation of these crowns.

No effect of fixation type on early and late mortality after total knee arthroplasty: a Dutch arthroplasty register study.

PURPOSE: Postoperative mortality is commonly reported as outcome measurement after total knee arthroplasty (TKA). Mortality might be influenced by multiple factors including cementation of the prosthesis. Until now, the influence of cementation on early and late mortality after TKA is unknown. The aim of the present study was to determine the effect of fixation on early and late mortality after primary TKA. METHODS: All patients in the Dutch Arthroplasty Register (LROI) with a primary TKA for osteoarthritis were eligible for inclusion. Data collected from 2007 to 2014 with follow-up until January 2020 were used. Survival analysis was performed by using Kaplan-Meier and Cox survival analysis to determine the mortality rate according to fixation. Adjustments were made for age at time of surgery, gender, American Society of Anaesthesiologists class, and year of surgery. RESULTS: In total 108,687 TKA were included for analysis, which comprised 95,857 cemented, 6,140 cementless and 6,690 hybrid TKA. The early and late mortality rate in cemented TKA was statistically not different compared to cementless or hybrid TKA at 30 days, 31-90 days, 91 days-1 year and 1-5 years. The hazard ratio at 30 days was 1.05 (CI 0.49-2.25) for hybrid fixation, and 1.46 (CI 0.74-2.90) for cementless fixation compared to cemented fixation. The 1-5 years hazard ratio was 1.06 (CI 0.96-1.17) and 0.97 (CI 0.87-1.08), respectively. CONCLUSION: Based on register data, method of fixation does not influence early mortality after primary TKA. This suggests that there is no preferred fixation technique for primary TKA based on the mortality rates. LEVEL OF EVIDENCE: IV.

Luting indirect restorations with resin cements versus composite resins: Effects of preheating and ultrasound energy on film thickness.

OBJECTIVE: This study aims to evaluate and compare the film thickness obtained with a resin cement and two composite resins, preheated and/or ultrasonically vibrated, as luting agents. MATERIALS AND METHODS: One hundred and twenty-six (126) pairs of resin discs were randomly assigned to six experimental groups (n = 21) according to luting agent (Variolink Esthetic LC, IPS Empress Direct or Estelite Omega) and cementation technique (preheating at 68°C and/or ultrasonic vibration). Specimens were luted by applying a controlled force. Following sectioning and film thickness measurement through field emission gun scanning electron microscopy, statistical analysis was carried out considering a 5% significance level. RESULTS: Statistically significant lower film thickness was observed in Variolink Esthetic LC group when compared to all composite resin groups (p < 0.001), except IPS Empress Direct preheated and ultrasonically vibrated group (p = 0.073). IPS Empress Direct with ultrasonic vibration yielded statistically lower film thickness values than Estelite Omega groups, regardless of luting technique (p < 0.05). Ultrasonically vibrated Estelite Omega groups showed statistically lower film thickness values than solely preheated groups (p < 0.05). CONCLUSIONS: Both Variolink Esthetic LC and IPS Empress Direct preheated and ultrasonically vibrated provided the lowest film thickness. The addition of ultrasonic vibration during cementation proved to be effective in reducing film thickness of both tested composite resins. CLINICAL SIGNIFICANCE: The cementation technique will have variable results depending on the luting material. Adhesive cementation protocols with composite resins should mainly consider ultrasonic vibration, but also preheating, as strategies for reducing film thickness. The tested resin cement, alongside with IPS Empress Direct composite resin preheated and ultrasonically vibrated, provided the lowest film thickness among the tested materials and techniques.

Revolution of Current Dental Zirconia: A Comprehensive Review.

The aim of this article is to comprehensively review the revolution of dental zirconia (Zir), including its types, properties, applications, and cementation procedures. A comprehensive search of PubMed and Embase was conducted. The search was limited to manuscripts published in English. The final search was conducted in October 2021. Newly developed monolithic Zir ceramics have substantially enhanced esthetics and translucency. However, this material must be further studied in vitro and in vivo to determine its long-term ability to maintain its exceptional properties. According to the literature, monolithic translucent Zir has had promising results and a high survival rate. Thus, the utilization of this material is indicated when strength and esthetics are needed. Both the materials and methods used for cementation of monolithic Zir have significantly improved, encouraging dentists to use this material, especially when a conservative approach is required. Zir restorations showed promising outcomes, particularly for monolithic Zir crowns supported with implant and fixed dental prostheses.

Assessment of Different Techniques for Adhesive Cementation of All-Ceramic Systems.

Background and Objectives: Modern esthetic dentistry is based on all-ceramic restorations. Dentists still have reservations about using these restorations due to a lack of understanding of the cementation technique, which depends on the type of ceramic used. The aim of the study is to evaluate the approaches and practices of clinicians regarding the adhesive cementation of all-ceramic restorations. Materials and Methods: An online questionnaire regarding the use of all-ceramic restorations and their bonding methods was designed by distinguishing the cementation of oxide and silica-based ceramics. The survey included dentists practicing in Timiș County, Romania. The questionnaire and the evaluation of the answers were designed based on the techniques and evidence from the literature. Results: Considering the work experience, we obtained two groups: group 1-1 to 6 years and group 2-6 to 9+ years. The results revealed significant values when comparing the two groups in the surface protocol and decontamination (p = 0.005), type of cement used (p = 0.002), and isolation techniques (p = 0.002). Conclusions: The results show that many clinicians need additional training to improve their cementing technique and avoid the confusion caused by insufficient information about the interrelationship between the type of ceramic and the cementation procedure.