Effect of cemented vs uncemented on outcomes for hemiarthroplasty in the elderly: A meta-analysis of randomized clinical trials.

PURPOSE: In patients undergoing hemiarthroplasty in the elderly, the choice of the cemented method remains controversial. This meta-analysis was undertaken to compare the impact of cemented vs uncemented on outcomes for hemiarthroplasty in the elderly. METHODS: This study included randomized controlled trials comparing the postoperative effects of cemented vs uncemented in patients with hemiarthroplasty. With no language restrictions, we searched Medline (Ovid), Embase (Ovid), Cochrane Central Register of Controlled Trials (Cochrane Collaboration), Clinical Trials.gov, the ISRCTN registry, as well as gray literature with no language restrictions from January 1966 to April 2023. Data were quantitatively summarized using a random-effects model. The primary outcome was 1-year mortality. RESULTS: This study included 13 randomized controlled trials with 3485 patients. The primary outcomes of the meta-analysis showed that cemented fixation in elderly patients undergoing hemiarthroplasty was superior to noncemented in 1-year mortality (risk ratio [RR] = 0.87, 95% confidence interval [CI]: 0.77, 0.97). Moreover, cemented was associated with a reduced risk of intraoperative periprosthetic fracture (RR = 0.19, 95% CI: 0.07, 0.50), postoperative periprosthetic fracture (RR = 0.34, 95% CI: 0.16,0.72), and loosening (RR = 0.33, 95% CI: 0.11, 0.97). CONCLUSIONS: Cemented hemiarthroplasty is superior to noncemented in terms of survival. Moreover, cementation reduces the incidence of some implant-related complications. More extensive trials are needed to provide adequate guidance for choosing the proper cemented method.

Influence of provisional cementation on the stability of adhesively bonded resin-based composite crowns.

PURPOSE: To investigate the influence of temporary cementation and subsequent bonding on the durability during in-vitro aging-simulation and fracture force of resin-based composite crowns. METHODS: Identical molar crowns (n=48, n=8 per group) were milled from resin-based composites and temporarily cemented and finally bonded to human molars. To simulate temporary application, crowns were cemented either with zinc-oxide-eugenol-cement (Tempbond) or with eugenol free zinc-oxide-cement (Tempbond NE). For a first simulation of a long-term provisional clinical application, thermal cycling, and mechanical loading (TCML 2 x 600 x 5°C-55°C, 2 minutes each cycle, distilled water, 240,000 cycles at 50N) was performed. After TCML all crowns were removed, cleaned, and luted either by using etch-and-rinse technique (Vococid, Futurabond U, Bifix QM) or a self-adhesive (Bifix SE) cementation system. A second thermal cycling and mechanical loading (TCML 2 x3,000 x 5°C/55°C, 2 minutes each cycle, distilled water, 1.2 x 106 at 50N) was accomplished to simulate 5 years of clinical application. To assess the survival of the crowns, the failure rates during TCML were documented. As controls, crowns were included without prior provisional cementation. After TCML all crowns were loaded to failure. Failure was categorized as fracture of the crown and partial loosening of the crown. RESULTS: All crowns survived both TCML procedures without any failures. The fracture values after TCML varied between 3,538.0 ± 1,041.2 N and 4,612.0 ± 801.5 N without significant (P= 0.146) differences between the individual groups. No correlation was found between fracture force and type of provisional cementation (zinc-oxide-eugenol vs. zinc-oxide: Pearson: -0.063/P= 0.672) or type of bonding (adhesive vs. self-adhesive: Pearson: -0.151/ P= 0.307). No different failure pattern was observed between the tested systems. CLINICAL SIGNIFICANCE: Regardless of the type of temporary cementation, there was no effect on the in-vitro performance or strength of the final permanently bonded crowns. Resin-based crowns might be bonded with adhesive or self-adhesive systems even after previous temporary cementation.

The effect of ascorbic acid, QMix and other conditioning solutions on the bond strength of adhesively luted glass fiber-reinforced composite posts to root dentin, a laboratory study.

PURPOSE: This study was designed to investigate the effect of post space conditioning with different solutions on the bond strength of glass FRC posts and evaluate the mode of resin failure. METHODS: Sixty extracted human single rooted teeth were root filled using a resin sealer and suitable gutta-percha cones. Post spaces were prepared, and the teeth randomly allocated into 5 groups according to their irrigation regimens which included the following solutions: 17 % EDTA, 2 % CHX, 3 % NaOCl, 10 % ascorbic acid and QMix solutions. Post spaces were irrigated with 5 ml of the solution for 15 s and subsequently washed with distilled water and dried with paper points. Glass FRC posts were cemented into their spaces using a self-adhesive resin cement. The specimens were mounted in plexiglass molds using autopolymerizing acrylic resin. A universal testing machine was used to measure post retention at a crosshead speed of 2 mm/min. The results were analyzed by one-way ANOVA followed by Tukey HSD test (α = 0.05). Dislodged posts and post spaces were examined microscopically to evaluate retention failure. RESULTS: The Ascorbic acid group exhibited the highest mean retentive strength value at 229 N, followed by QMix at 198 N, NaOCl at 186 N, CHX at 170 N, and EDTA at 124 N. The mean value of the ascorbic acid group was significantly higher than EDTA group, p = 0.012. The failure category was primarily mixed. CONCLUSIONS: Rinsing post spaces with ascorbic acid exhibited significantly superior bond strength. The failure mode was mixed. CLINICAL SIGNIFICANCE: Irrigating post spaces with ascorbic acid solution before luting FRC posts significantly improves their bond strength compared to irrigation with EDTA solution. Irrigation with QMix solution produced the second highest retentive strength but showed no statistical significance when compared to using ascorbic acid, NaOCl, CHX, or EDTA solutions.

Biological interaction, esthetics, handling, and loss rate of temporary luting cements - a clinical single-blind randomized controlled trial.

OBJECTIVES: To evaluate three temporary luting cements in terms of their restoration loss rates, biological interactions, esthetic properties, and handling characteristics. MATERIALS AND METHODS: 75 adults requiring fixed prosthodontics voluntarily participated in a single-blind, randomized controlled trial. After preparation, temporary restorations were luted with a randomly selected temporary luting cement (either Provicol QM Plus (PQP), Bifix Temp (BT), or Provicol QM Aesthetic (PQA)). Clinical examinations were performed one to two weeks after cementation. The following criteria were evaluated: tooth vitality, percussion, hypersensitivity, gingival bleeding, odor formation, esthetics, cement handling, removability, cleanability, and retention loss. Antagonistic teeth served as controls. Statistical analysis was performed using the paired t-test, one-way ANOVA, Pearson's chi-square and Fisher's exact test, where appropriate. RESULTS: The overall loss rate of temporary restorations was 16.0%, showing no cement-specific differences. Postoperative hypersensitivity occurred in 8% of cases regardless of cement type. Esthetic impairment was reported by 31% of the PQP-fixed restorations, compared with 4.0% and 4.2% of the BT and PQA-bonded restorations. Cement application was reported to be easy in 100% of cases, excess removal in 88-96%, depending on the cement used. CONCLUSIONS: The choice of luting material affects the esthetic appearance of a temporary restoration and should be considered, particularly in restorations in esthetically demanding areas. No significant differences between the cements were identified regarding biocompatibility, handling, and loss rate. CLINICAL RELEVANCE: Translucent cements can help to reduce color interferences, resulting in a more appealing appearance of the temporary restoration.

The influence of finishing line and luting material selection on the seating accuracy of CAD/CAM indirect composite restorations.

OBJECTIVES: This study aimed to assess the seating accuracy of resin composite CAD/CAM overlay restorations, employing various preparation designs and luting materials (pre-heated composite (HC) or resin cement (RC)). METHODS: A human molar's STL file was utilized to create 100 3D-printed resin tooth replicas, randomly distributed into 5 groups (n = 20) based on finishing line preparation designs: 1) Rounded shoulder above the dental equator - DE (SA); 2) Chamfer above the DE (CA); 3) Butt joint above the DE (BJ); 4) Rounded shoulder below the DE (SB); 5) Chamfer below the DE (CB). Digital impressions were acquired for all replicas, and restorations milled using Tetric CAD (Ivoclar Vivadent). The restorations were luted with HC (Tetric Prime, Ivoclar Vivadent) or RC (RelyX Universal, 3 M). Seating accuracy was evaluated through digital scans during try-in without any luting agent and post-cementation using a 3D analysis software (Geomagic wrap, 3D Systems). Data were statistically analyzed using Two-Way ANOVA (p < 0.05). RESULTS: The type of luting material (RC vs HC), preparation design, and their interactions significantly impacted 3D seating of the restorations (p < 0.001). HC exhibited higer volumetric increase than RC. BJ and CA designs consistently demonstrated superior seating accuracy, irrespective of the luting material used. CONCLUSIONS: The utilization of pre-heated composite resin could negatively influence the seating of overlay restorations, probably due to its higher viscosity when compared to the resin cement. However, when HC is selected as luting agent, preparation designs lacking internal angles are recommended for enhancing the precision of overlays seating.

The effect of restorative material selection and cementation procedures on the durability of endocrowns in the anterior teeth: an in-vitro study.

OBJECTIVE: To investigate the fracture resistance and failure modalities of anterior endocrown restorations fabricated employing diverse ceramic materials, and bonded using various cementation methodologies. MATERIALS AND METHODS: Forty maxillary central incisors were divided into two main groups based on the ceramic materials used; GroupI (Zir): zirconia endocrwons (Zolid HT+, Ceramill, Amanngirrbach) and GroupII (E-Max): e-max endocrowns (IPS e.max CAD, Ivoclar Vivadent). Both groups were further split into two subgroups depending on the cementation protocols; subgroup IA "ZirMDP": endocowns cemented with MDP primer + MDP resin cement, subgroup IB (ZirNon-MDP): cemented with MDP primer + non-MDP resin cement, subgroup IIA (E-maxMDP): cemented with MDP primer + MDP resin cement, subgroup IIB (E-maxNon-MDP): cemented with MDP primer + non-MDP resin cement. (n = 10/subgroup). Endocrowns were manufactured using CAD/ CAM. Teeth were subjected to 10,000 thermal cycles. The fracture test was performed at 45o with a palatal force direction until the fracture occurred. Test results were recorded in Newton. The failure mode was examined using a stereomicroscope. A One-way ANOVA test was utilized to compare different groups regarding fracture strength values. Tukey`s Post Hoc was utilized for multiple comparisons. RESULTS: The comparative analysis of fracture strength across the diverse groups yielded non-significant differences, as indicated by a p-value exceeding 0.05. Nonetheless, an observable trend emerged regarding the mode of failure. Specifically, a statistically significant prevalence was noted in fractures localized within the endocrown/tooth complex below the cementoenamel junction (CEJ) across all groups, except for Group IIB, "E-max Non-MDP," where fractures within the endocrown/tooth complex occurred above the CEJ. CONCLUSIONS: Combining an MDP-based primer with an MDP-based resin cement did not result in a significant effect on the anterior endocrown fracture strength. CLINICAL RELEVANCE: Regardless of the presence of the MDP monomer in its composition, adhesive resin cement achieved highly successful fracture strength when used with MDP-based ceramic primers. Additionally, ceramic materials exhibiting elastic moduli surpassing those of dentin are discouraged due to their propensity to induce catastrophic fractures within the tooth structure.

Clinical guidelines for posterior semidirect composite resin restorations: a case report with a 17-month follow-up.

Patients are always looking for conservative, esthetic, and long-lasting dental restorations, and the technique used directly influences the longevity of the treatment. The location of the restoration in the mouth and the extent of the decay influence the treatment choice. The larger the dimensions of the cavity preparation, the greater the difficulties in restoring the tooth using direct techniques. The semidirect technique, when indicated, can achieve satisfactory results. It is a relatively easy procedure, consisting of tooth preparation to receive an indirect restoration, fabrication of an alginate impression, fabrication of the composite resin restoration on a flexible cast, cementation, removal of excess cement, and occlusal adjustment. The aim of this case report is to present a viable alternative to direct and indirect restorations for posterior teeth with extensive decay. The article describes the extraoral semidirect technique for fabricating a composite resin restoration, highlighting its indications and discussing advantages and disadvantages.

[Study on the pressure on ceramic veneers during cementation]. / Izuchenie velichiny davleniya na keramicheskie viniry vo vremya ikh tsementirovaniya.

OBJECTIVE: The aim of the study is measuring the magnitude and determining the method of finger pressure exerted by doctors on ceramic veneers during their fixation. MATERIAL AND METHODS: A simulation model was designed in order to measure the volume of finger pressure. Veneers were produced for 2 central incisors. Doctors alternately placed veneers on the model and applied pressure on them for 20 seconds simulating the clinical stage of cementing. The operator recorded the maximum readings of the scales and entered the result on the research protocol. In addition, it was recorded which finger the doctor exerts on the veneer during its cementing to ensure a tight fit: thumb or index finger. RESULTS: The values obtained during cementation of 54% doctors ranged up to 1 kg, 27% of doctors from 1 to 2 kg and only 19% more than 2 kg. 80% of doctors applied the main pressure on the veneer using their thumb, while the pressure force was 1.4 kg. For those doctors who pressed the veneer to the tooth with their index finger, the impact value was 0.8 kg. CONCLUSION: The finger pressure on the veneer during cementation applied by dentists varies, the average pressure on the veneers was about 1.5 kg. The amount of pressure on cement during laboratory tests of cements for fixing veneers differs from clinical values many times. The development of a veneers fixation protocol, taking into account the conducted research, will ensure a reliable and accurate fit of the veneer at the stage of its cementing.

Effect of cement spacer on fit accuracy and fracture strength of 3-unit and 4-unit zirconia frameworks.

BACKGROUND: Cement spacer is essential for compensating deformation of zirconia restoration after sintering shrinkage, allowing proper seating and better fracture resistance of the restoration. Studies assessing the effect of cement spacer on fit accuracy and fracture strength of zirconia frameworks are missing in the literature. Therefore, the aim of this study was to evaluate the effect of different cement spacer settings on fit accuracy and fracture strength of 3-unit and 4-unit zirconia frameworks. METHODS: Sixty standardized stainless-steel master dies were manufactured with 2 prepared abutments for fabricating 3-unit and 4-unit zirconia frameworks. The frameworks were assigned into 6 groups (n = 10) according to cement spacer setting (30 µm, 50 µm, and 80 µm) as follows: 3-unit frameworks; 3u-30, 3u-50, 3u-80, and 4-unit frameworks; 4u-30, 4u-50, and 4u-80. The frameworks were assessed for fit accuracy with the replica method. The specimens were cemented to their corresponding dies, and the fracture strength was measured in a universal testing machine. The Weibull parameters were calculated for the study groups and fractured specimens were inspected for failure mode. Two-Way ANOVA followed by Tukey test for pairwise comparison between study groups (α = 0.05). RESULTS: The cement spacer had a significant effect on both fit accuracy and fracture strength for 3-unit and 4-unit frameworks. The 50 µm spacer had significantly better fit accuracy followed by 80 µm, and 30 µm spacers. Both 50 µm and 80 µm spacers had similar fracture strength, and both had significantly better strength than 30 µm spacer. CONCLUSIONS: For both 3-unit and 4-unit zirconia frameworks, 50 µm cement spacer can be recommended over 30 µm and 80 µm spacers for significantly better fit accuracy and adequate fracture strength.

Study on triaxial compression performance and damage characteristics of fiber-reinforced ecological matrix cementing gangue gypsum fill material.

Polypropylene fiber was equally mixed into alkali-activated slag fly ash geopolymer in order to ensure the filling effect of mine goaf and improve the stability of cemented gangue paste filling material with ecological matrix. Triaxial compression tests were then conducted under various conditions. The mechanical properties and damage characteristics of composite paste filling materials are studied, and the damage evolution model of paste filling materials under triaxial compression is established, based on the deviatoric stress-strain curve generated by the progressive failure behavior of samples. Internal physical and chemical mechanisms of the evolution of structure and characteristics are elucidated and comprehended via the use of SEM-EDS and XRD micro-techniques. The results show that the fiber can effectively improve the ultimate strength and the corresponding effective stress strength index of the sample within the scope of the experimental study. The best strengthening effect is achieved when the amount of NaOH is 3% of the mass of the solid material, the amount of fiber is 5‰ of the mass of the solid material, and the length of the fiber is about 12 mm. The action mode of the fiber in the sample is mainly divided into single-grip anchoring and three-dimensional mesh traction. As the crack initiates and develops, connection occurs in the matrix, where the fiber has an obvious interference and retardation effect on the crack propagation, thereby transforming the brittle failure into a ductile failure and consequently improving the fracture properties of the ecological cementitious coal gangue matrix. The theoretical damage evolution model of a segmented filling body is constructed by taking the initial compaction stage end point as the critical point, and the curve of the damage evolution model of the specimen under different conditions is obtained. The theoretical model is verified by the results from the triaxial compression test. We concluded that the experimental curve is in good agreement with the theoretical curve. Therefore, the established theoretical model has a certain reference value for the analysis and evaluation of the mechanical properties of paste filling materials. The research results can improve the utilization rate of solid waste resources.

A conservative approach to localize loose implant screw through cemented crown: an in vitro experimental study.

BACKGROUND: Retrieval of cement-retained implant-supported restorations is intriguing in cases of screw loosening. Detecting the estimated size of the screw access hole (SAH) could decrease destruction to the prosthesis and preserve the crown. OBJECTIVES: To precisely localize loose implant screws through cemented crowns to reduce crown damage after screw loosening. MATERIALS AND METHODS: In this in vitro study, 60 cement-retained implants supported 30 zirconia-based, and 30 ceramics fused to metal (CFM) lower molar crowns were invented, and each was subdivided into three subgroups (10 each). In group I (AI/BI) (control), SAH was created with the aid of orthopantomography (OPG). In contrast, in group II (zirconia-crown), SAH was created with the aid of CBCT + 3D printed surgical guide with a 2 mm metal sleeve in subgroups IIA/IIIA and CBCT + MAR was used to develop SAH in subgroups IIB/IIIB. SEM and Micro-CT scanned the SAH openings to determine the diameter of the hole, cracking, chipping, and chipping volume. RESULTS: Regarding the effect of plane CBCT and CBCT + MAR on prepared crowns, a highly significant association between group I with group II (p = 0.001) and group III (p = 0.002) was detected. Regarding the cracking of SAH, significant differences between the zirconium crown and CFM restoration (p = 0.009) were found, while for the chipping, no significant association was seen between groups (p = 0.19). CONCLUSIONS: CBCT, either as a plane CBCT or with MAR, significantly improved the accuracy of drilling the screw channel and decreased injury to the existing restoration and abutment, aiding in better localization of SAH in loosened implant abutment screws.

Adhesive Cementation of CAD/CAM Silica-based Ceramics: Effect of Adhesive Type and Long-term Aging on the Bond Strength to Composite Cement.

PURPOSE: To investigate the effect of adhesive type and long-term aging on the shear bond strength (SBS) between silica-based ceramics and composite cement (CC). MATERIALS AND METHODS: Lithium-silicate (LS), feldspathic (FD) and polymer-infiltrated ceramic (PIC) blocks were sectioned (10 x 12 x 2 mm) and divided into 24 groups considering the factors: "ceramics" (LS, FD, and PIC), "adhesive" (Ctrl: without adhesive; 2SC: 2-step conventional; 3SC: 3-step conventional; 1SU: 1-step universal), and "aging" (non-aged or aged [A]). After the surface treatments, CC cylinders (n = 15, Ø = 2 mm; height = 2 mm) were made and half of the samples were subjected to thermocycling (10,000) and stored in water at 37°C for 18 months. The samples were submitted to SBS testing (100 kgf, 1 mm/min) and failure analysis. Extra samples were prepared for microscopic analysis of the adhesive interface. SBS (MPa) data was analyzed by 3-way ANOVA and Tukey's test (5%). Weibull analysis was performed on the SBS data. RESULTS: All factors and interactions were significant for SBS (p<0.05). Before aging, there was no significant difference between the tested groups and the respective control groups. After aging, the LS_1SU (22.18 ± 7.74) and LS_2SC (17.32 ± 5.86) groups exhibited significantly lower SBS than did the LS_Ctrl (30.30 ± 6.11). Only the LS_1SU group showed a significant decrease in SBS after aging vs without aging. The LS_1SU (12.20) group showed the highest Weibull modulus, which was significantly higher than LS_2SC_A (2.82) and LS_1SU_A (3.15) groups. CONCLUSION: No type of adhesive applied after silane benefitted the long-term adhesion of silica-based ceramics to CC in comparison to the groups without adhesive.

Tendencias en la cirugía de artroplastía total de rodilla en Chile. ¿Cómo las estamos operando? / Trends in total knee replacement surgery in Chile. How are we operating them?

INTRODUCCION La artroplastía total de rodilla (ATR), que ha tenido un aumento importante en la población en las últimas décadas, presenta una gran variación en su estudio y técnica entre los distintos países. En la actualidad no hay datos nacionales registrados que evalúen la forma de su implementación. Objetivo Registrar las tendencias respecto de la ATR en distintos aspectos en Chile y compararlas con los registros de otros países. MATERIALES y METODOS Se realizó una encuesta vía email a cirujanos de rodilla en Chile considerando cuatro aspectos: generalidades, estudio preoperatorio, técnica quirúrgica y técnica de cementación. Se excluyeron las encuestas que no rellenadas por completo. Se analizaron los datos generales y separados según años de experiencia (ADE). Se compararon los datos con los obtenidos en estudios internacionales. RESULTADOS Se obtuvieron 87 encuestas completas. La mayoría de los encuestados realizaba entre 25 y 50 ATR en 1 año (44%), y el 16%, más de 75. Sólo un 20% utilizaba la modalidad ambulatoria, y un 43% creía que siempre deben ser hospitalizadas (mayor frecuencia en los cirujanos con más de 10 ADE). Un 18% utilizaba algún sistema robótico, con mayor frecuencia en cirujanos con más de 10 ADE; los sistemas más usados fueron ROSA y CORI. El 90% creía que la ATR debería ser parte del programa de Garantías Explícitas de Salud (GES), sin diferencias según ADE. El 81% usaba sistema estabilizado posterior (posterior-estabilized, PS, en inglés), 96% realizaba un abordaje parapatelar medial, 82% usaba guía extramedular tibial, 41% tendía a recambiar la patela, y un 35% no usaba torniquete (ninguna de las variables mostró diferencias según ADE). Sólo un 31% utilizaba cementación al vacío (mayor frecuencia en el grupo con menos de 10 ADE), 95% colocaba el cemento en componentes y en hueso, 75% colocaba en la quilla, y 56% utilizaba el dedo para colocarlo (sólo 22% con pistola). La secuencia más frecuente de cementación fue tibia-fémur-patela. En la mayoría de los aspectos evaluados, se observaron diferencias importantes con estudios de otros países. CONCLUSION Existe una gran variabilidad en la realización de ATR en Chile, con tendencias distintas a las de otros países. En general, en relación con los distintos ADE, no hay grandes diferencias en la técnica quirúrgica, sí habiendo diferencias en la técnica de cementación y en el uso de sistemas robóticos

INTRODUCTION Total knee replacement (TKR) significantly increased among the population in recent decades, and it shows great variation in its study and technique in different countries. There is no registered Chilean data to assess TKR implementation. Objective To record the trends in TKR in different aspects within Chile and compare them with records from other countries. MATERIALS AND METHODS We conducted an email survey among knee surgeons in Chile considering four aspects: general features, preoperative study, surgical technique, and cementation technique. We excluded surveys not completed in full. The analyses included overall data and data per years of experience (YOEs), and we compared the results with those of international studies. RESULTS We obtained 87 complete surveys. Most respondents performed 25 to 50 TKRs each year (44%), with only 16% performing over 75 TKRs. Only 20% used the ambulatory modality, while 43% believed patients always require hospitalization (especially surgeons with more than 10 YOEs). Robotic systems were used by 18% of the surgeons, especially those with more than 10 YOEs; the most used systems were ROSA and CORI. In total 90% of the respondents believed TKR should be part of the Explicit Health Guarantees (Garantías Explícitas de Salud, GES, in Spanish) program, with no differences in terms of YOEs. A total of 81% used the posterior-stabilized (PS) system, 96% performed a medial parapatellar approach, 82% used an extramedullary tibial guide, 41% tended to replace the patella, and 35% did not use a tourniquet (none of the variables showed differences according to YOEs). Only 31% used vacuum cementation (with a higher frequency in the group with fewer than 10 YOEs), 95% placed cement on components and bone, 75% placed it in the keel, and 56% used finger packing (only 22% with a gun). The most common cementation sequence was tibia femur-patella. In most aspects evaluated, we observed important differences compared with studies from other countries. CONCLUSION There is a high variability in the performance of TKR in Chile, with different trends compared with those of other countries. Overall, there are no major differences in the surgical technique concerning YOEs, although there is variation in the cementation technique and the use of robotic systems

Effect of cement type on vertical marginal discrepancy and residual excess cement in screwmentable and cementable implant-supported monolithic zirconia crowns.

The purpose of this study was to investigate the vertical marginal discrepancy (VMD) and residual excess cement (REC) of cementable and screwmentable monolithic zirconia crowns cemented with different types of cement. Abutments were attached to 40 implant analogues. Crowns were created using computer-aided design/computer-aided manufacturing technology from monolithic zirconia blocks, either with or without a screw access hole (SAC). Crowns created both ways were split into two groups and cemented with resin and zinc polycarboxylate cement under a 5-kg weight. VMD and REC values were evaluated using an X20 zoom stereomicroscope. Data were analysed using two-way ANOVA and the Bonferroni test. According to the two-way ANOVA results, REC measurements differed significantly in the crown design and cement groups. However, whilst VMD values were significantly different in both crown design groups, there was no significant difference in the cement groups. According to the Bonferroni test results, the highest REC (157.241 ± 44.29 µm) and VMD (68.052 ± 16.19 µm) values were found in the crowns without SAC and cemented with zinc polycarboxylate. Screwmentable crowns are more effective than cementable crowns in reducing REC and VMD. Whilst polycarboxylate cement reduces VMD in screwmentable crowns, resin cement is more suitable for cementable crowns.

Factors influencing the bond strength of additively manufactured crown materials in dentistry: A systematic review of in vitro studies.

OBJECTIVE: The purpose of this systematic review was to investigate how different interventions can impact the bond strength of additively manufactured crown materials after cementation. DATA/SOURCES: Four online databases Ovid MEDLINE, Scopus, Web of Science and Google Scholar were searched up to January 2023. Inclusion criteria were English-language publications, full-text, and in vitro studies only. Exclusion criteria were studies that did not assess the bonding of an additively manufactured crown material to cement or did not conduct any bond strength tests. An assessment of risk of bias was done in accordance with a modified Consolidated Standards of Reporting Trials (CONSORT) checklist. Each study was analysed and compared based on the interventions and bond strength results. STUDY SELECTION: Six studies satisfied the inclusion and exclusion criteria, five of which evaluated photopolymerised resin and one that tested zirconia manufacturing via 3D printing. All studies observed a low risk of bias. The interventions applied included the type of surface pretreatments, airborne-particle abrasion pressure, cement type, taper of crown, and artificial aging. Three studies compared the bonding performance to milled materials. CONCLUSIONS: The bond strength of crown materials additively manufactured from photopolymers presented high values and are comparable to milled materials. The systematic review demonstrated there was no definite superior cement type, but airborne-particle abrasion with alumina was generally recommended. There is a clear gap in the literature regarding the bond strength of additively manufactured crowns. Therefore, further research is necessary to evaluate its clinical applicability for permanent restorations. CLINICAL SIGNIFICANCE: Factors influencing the bond strength of additively manufactured crown materials should be evaluated so dental professionals can adopt procedures that promote the strongest bond.

Prolonged post-washing in ethanol decreases bond strength of additively manufactured crown materials.

OBJECTIVES: This study aimed to investigate the effect of post-washing duration and crown thickness on the bond strength between additively manufactured crown materials and dental cement in vitro. METHODS: Rectangular-shaped specimens of two thicknesses (1.5 and 2.0 mm) were additively manufactured from permanent VarseoSmile Crown (VC) and long-term temporary NextDent (ND) materials. The specimens were post-washed (n = 160) in ethanol for 5 min, 10 min, 1 h, and 8 h then cemented with dual-cure resin cement. Twenty PMMA (TC) were milled as a control. A chevron-notch test was performed to measure the maximum load until failure (N). Interfacial bond strength (J/m2) was calculated and statistically analysed. The mode of failure was analysed by scanning electron microscopy (SEM). RESULTS: There was a significant difference in the bond strength between all groups (p < 0.01). VC at 1.5mm thickness post-washed for 10 min showed the highest mean bond strength (1.77 ±0.96 J/m2) while VC at 2.0mm thickness post-washed for 8 h showed the lowest (0.22 ±0.10 J/m2). Exposure to ethanol for 8 h resulted in lower bond strength. Within the type of material, there were no differences in bond strength between the thicknesses when post-washed for the same duration. CONCLUSIONS: Prolonged post-washing of AM crown materials can significantly decrease the bond strength to resin cement. There were no differences between the permanent and long-term temporary AM materials. When post-washed for 5 min, AM materials observed comparable or higher bond strength values compared to PMMA. CLINICAL SIGNIFICANCE: The output of this research serves as a guide for dental practitioners, emphasising the importance of adhering to correct post-washing procedures for optimal bond strength of additively manufactured crown materials.

[Cement in revision arthroplasty-what about the "glacier effect"? : Case studies viewed from different perspectives]. / Zement in der Revisionsendoprothetik ­ Was ist mit dem "Gletschereffekt"? : Fallbeispiele aus unterschiedlichen Perspektiven betrachtet.

BACKGROUND: The number of operations concerning revision arthroplasty has been increasing continuously in recent years, and it can be assumed that they will continue to increase in the future. If an arthroplasty implant becomes loose, it must be changed. The question often arises as to how the new implant should be fixed in the bone. ADVANTAGES: Revision implants can be inserted into the bone without cement. In the subsequent period, a secondary osseointegration of the implant takes place. Another possibility is to anchor the implant by using bone cement. The advantage of cemented anchorage is that the implant is firmly fixed in the bone, in principle, immediately, and it is possible to fully load the implant directly. Direct postoperative full weight bearing is helpful, especially for older and multimorbid patients, in order to achieve rapid mobilization. PREREQUISITES AND CHALLENGES: When using cement in revision cases, however, there are a few prerequisites and challenges that the surgeon should definitely take into account. In the case of revision, the bone in the former implant bed is often deficient and appears thinned and sclerosed. It is, therefore, important to analyze the bone quality preoperatively on radiographic images and to include it in the planning of the anchoring strategy. In addition, the individual bone quality of the patient must also be taken into account intraoperatively. In any case, it must be clarified whether the basic prerequisites for the sufficient bond strength of the cement with the bone to be formed can still be met. Furthermore, the principles of cementing technique must be strictly observed, and the goal of a perfect cement mantle must be aimed for. If the indication for this is overstated, early loosening of the cemented revision arthroplasty is very likely.

Formulations of NaOCl-based in liquid, gel form or with surfactants on dentin deproteinization before fiber post cementation.

The objective of the study was to evaluate the effects of dentin deproteinization protocols for post space using different formulations containing sodium hypochlorite before fiber post cementation with self-adhesive resinous cement. The groups were divided according to the irrigation protocol (DWC, SHS, SHT and SHG). The residue cleanliness, bond strength, adhesive failure pattern, and tag formation at the adhesive interface between the self-adhesive cement and the dentin were evaluated. For this, analysis in scanning electron microscope, push-out test and confocal laser scanning microscopy were performed. The SHT protocol showed the highest residue cleanliness on the dentin surface of the post space (p<0.05). In addition, SHT protocol showed highest bond strength and tag formation in the cervical and middle thirds (p<0.05). Dentin deproteinization with sodium hypochlorite with surfactant provided the best dentin cleaning of residues, bond strength and tag formation after cementation of the fiber post with self-adhesive cement.

An overview of bone cement: Perioperative considerations, complications, outcomes and future implications.

Polymethyl methacrylate is commonly known as bone cement and is widely used for implant fixation in various orthopaedic arthroplasty and trauma surgery. The first bone cement use in orthopaedics is widely accredited to the famous English surgeon, John Charnley, who in 1958, used it for total hip arthroplasty. Since then, there have been many developments in cementing techniques in arthroplasty surgery. This overview aims to cover the perioperative considerations of bone cement, including cementing techniques, current outcomes and complications such as bone cement implantation syndrome. The overview will additionally consider future developments involving bone cement in orthopaedic arthroplasty.

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.