Vertical marginal gap and internal fit of virgilite-based lithium disilicate glass ceramic veneers with different preparation designs.

PURPOSE: To evaluate and compare internal fit and marginal adaptation of conventional lithium disilicate (LDS) glass ceramics and LDS containing virgilite computer-aided design and manufacturing (CAD-CAM) blocks before and after aging. MATERIALS AND METHODS: Seventy-two epoxy replicated dies from two prepared maxillary right central incisors acrylic typodont were divided into two groups of different preparation designs (n = 36): Group I, incisal butt-joint, and Group P, incisal overlap. Each group was further subdivided into two equal groups according to ceramic material (n = 18): Group E, IPS e.max CAD, and Group T, Tessera advanced lithium disilicate (ALD) CAD-CAM blocks. The replica technique was used to assess the internal fit using a stereomicroscope at 45× magnification. Laminate veneers were cemented to their corresponding epoxy dies, then the vertical marginal gap was evaluated before and after thermal cycling. Repeated measures analysis of variance (ANOVA) were used for marginal fit data and 2-way ANOVA for internal fit measurements (α = 0.05). RESULTS: For internal fit, there were no significant differences between tested groups. For vertical marginal gap results, two-way ANOVA showed that only aging had a significant effect on the vertical marginal gap (p < 0.001), while different CAD-CAM materials and preparation designs did not affect the vertical marginal gap. CONCLUSIONS: The vertical marginal gap and internal fits of IPS e.max CAD and CEREC Tessera CAD for both preparation designs were comparable. Aging significantly affected the vertical marginal gap of the laminate veneers of both materials and both preparation designs; however, all were within clinically acceptable ranges before and after aging.

Effect of the scanner type on the marginal gap and internal fit of two monolithic CAD/CAM esthetic crown materials: An in vitro study.

BACKGROUND: The durability of indirect restorations is significantly influenced by marginal adaptation and internal fit. The use of computer-aided design/computer-aided manufacturing (CAD/CAM) with digital impressions has reduced dental prosthesis fabrication errors, improving the long-term survivability of the restorations. OBJECTIVES: The present study assessed the impact of intraoral and extraoral scanning methods on the marginal adaptation and internal fit of 2 different types of monolithic crowns manufactured using CAD/CAM. MATERIAL AND METHODS: A total of 40 three-dimensional (3D) resin-printed dies were randomly assigned to 2 groups based on the type of crown material (n = 20 per group). Each group was divided into 2 subgroups (n = 10 per group) according to the die-scanning technique: subgroup A, scanned using the intraoral scanner (IOS) Primescan; and subgroup B, scanned using the extraoral scanner (EOS) inEos X5. The digitized photos were converted into a 3D virtual crown design using CAD software. The internal discrepancy values, and the marginal gap between the 3D resin-printed die and the crown were assessed using a ×50 digital microscope. The data was checked for normality with the Kolmogorov-Smirnov test, and the Mann-Whitney U test was used to compare the tested groups. The collected data was analyzed at a significance level set at p < 0.05. RESULTS: The different scanning techniques used had a statistically significant effect on the vertical marginal gap and the internal fit [µm] (p < 0.05). As far as the crown materials are concerned, BRILLIANT Crios showed a significantly higher marginal gap as compared to Tetric CAD when scanned with inEos X5 (p = 0.004), whereas the differences were insignificant with regard to the internal fit (p > 0.05).The crown parameters tested with both scanning systems were within the clinically acceptable ranges. CONCLUSIONS: Scanning methods and crown materials had an impact on the internal fit and vertical marginal gap of monolithic crowns.

Effect of multiple firings on optical and mechanical properties of Virgilite-containing lithium disilicate glass-ceramic of varying thickness.

OBJECTIVES: To investigate the effect of multiple firings on color, translucency, and biaxial flexure strength of Virgilite-containing (Li0.5Al0.5Si2.5O6) lithium disilicate glass ceramics of varying thickness. MATERIALS AND METHODS: Sixty discs were prepared from Virgilite-containing lithium disilicate blocks. Discs were divided according to thickness (n = 30) into T0.5 (0.5 mm) and T1.0 (1.0 mm). Each thickness was divided according to the number of firing cycles (n = 10); F1 (Control group): 1 firing cycle; F3: 3 firing cycles, and F5: 5 firing cycles. The discs were tested for color change (ΔE00) and translucency (TP00) using a spectrophotometer. Then, all samples were subjected to biaxial flexure strength testing using a universal testing machine. Data were collected and statistically analyzed (α = 0.5). For chemical analysis, six additional T0.5 discs (2 for each firing cycle) were prepared; for each firing cycle one disc was subjected to X-ray diffraction analysis (XRD) and another disc was subjected to Energy dispersive X-ray spectroscopy (EDX) and Scanning electron microscope (SEM). RESULTS: Repeated firing significantly reduced the translucency of F3 and F5 compared to F1 in T0.5 (p < 0.001), while for T1.0 only F5 showed a significant decrease in TP00 (p < 0.001). For ΔE00, a significant increase was recorded with repeated firings (p < 0.05) while a significant decrease resulted in the biaxial flexure strength regardless of thickness. CONCLUSIONS: Repeated firings had a negative effect on both the optical and mechanical properties of the Virgilite-containing lithium disilicate glass ceramics. CLINICAL RELEVANCE: Repeated firings should be avoided with Virgilite-containing lithium disilicate ceramics to decrease fracture liability and preserve restoration esthetics.

Marginal adaptation and fracture resistance of virgilite-based occlusal veneers with varying thickness.

STATEMENT OF PROBLEM: CAD/CAM occlusal veneers have been developed for minimally invasive prosthetic restoration of eroded teeth. Marginal adaptation and fracture resistance are crucial for the long-term survivability and clinical success of such restorations. Virgilite-based lithium disilicate glass-ceramic is a newly introduced material with claims of high strength. However, constructing occlusal veneers from this material of varying thickness has not been investigated. PURPOSE: The current study aimed to assess the impact of CAD/CAM occlusal veneer thickness and materials on marginal adaptation and fracture resistance. MATERIALS AND METHODS: Thirty-two occlusal veneers were constructed and divided into two groups (n = 16) based on the CAD/CAM material into Brilliant Crios and CEREC Tessera. Each group was further subdivided into two subgroups (n = 8) according to the thickness: 0.6 and 0.9 mm. Occlusal veneers were bonded to epoxy resin dies. The marginal gap was evaluated before and after thermodynamic aging. Fracture resistance and failure mode were evaluated for the same samples after aging. Marginal adaptation was analyzed using the Mann-Whitney U test. Fracture resistance was analyzed using Weibull analysis (α = 0.05). RESULTS: The marginal gap was significantly increased following thermodynamic aging for tested groups (P < 0.001). CEREC Tessera showed a significantly higher marginal gap than Brilliant Crios before and after aging for both thicknesses (P < 0.05). CEREC Tessera recorded lower significant fracture load values compared to Brilliant Crios (P < 0.05). CONCLUSIONS: Both CEREC Tessera and Brilliant Crios demonstrated clinically accepted marginal gap values. All groups showed fracture resistance values higher than the average masticatory forces in the premolar region except for 0.6 mm CEREC Tessera. CLINICAL IMPLICATIONS: Reinforced composite occlusal veneers demonstrated more favorable outcomes in terms of marginal gap and fracture resistance at both tested thicknesses compared to virgilite-based lithium disilicate glass-ceramic. Additionally, caution should be exercised during the construction of occlusal veneers from virgilite-based lithium disilicate glass-ceramic with reduced thickness.

Survival difference among adult and pediatric mediastinal yolk sac tumors cases: A meta-analysis of case reports.

BACKGROUND: Mediastinal Yolk sac tumors (YST) are rare and highly malignant extragonadal germ cell tumors with rapid growth and early metastases. We sought to conduct a meta-analysis of published case reports/case series to compare differences in survival, demographics, and treatment modalities between adult and pediatric patients with YST. METHODS: Ovid Embase, Cochrane, and Ovid Medline databases were searched for primary mediastinal pure YST cases. The primary outcome was overall survival (OS). Log-rank and Cox regression were used. This study is registered on PROSPERO (CRD42022367586). RESULTS: Among 846 studies, 87 met our inclusion criteria including 130 patients (Adults: 90 and Pediatrics: 40). About 41.5% of the patients were from the United States. The median age was 23.0 (Q1-Q3: 17.0-30.0), 88.5% were males, and (32.3%) were Asian. Stage II represented almost 40%. AFP was elevated in 96.9%. Respiratory distress was the presenting symptom in 65.4%. Chemotherapy, radiotherapy, and surgery were utilized in 84.6, 23.1, and 64.7% respectively. Median OS was 24 months (Adults: 23 months, Pediatrics: 25 months, P = 0.89). 3- and 5-year OS were 34.4% and 22.9% in adults and 41.5% and 41.5% in pediatrics, respectively. On multivariate analysis, anterior location of tumors, receipt of chemotherapy, and undergoing surgery were associated with better OS. CONCLUSION: Primary mediastinal YSTs are rare, but lethal neoplasms. Our meta-analysis showed that mediastinal YSTs mimic other non-seminomatous mediastinal GCTs in terms of clinical characteristics and available treatment options. Early diagnosis, neoadjuvant chemotherapy, and surgical resection are the key points for effective management and improved outcomes.

Alumina and glass-bead blasting effect on bond strength of zirconia using 10-methacryloyloxydecyl dihydrogen phosphate (MDP) containing self-adhesive resin cement and primers.

In fact, bonding of zirconia restorations is still a big challenge in clinical situations and many bonding protocols discussed in literature might be still controversial. The aim of this was to study assess the bond strength of zirconia after alumina and glass-bead pre-treatments with two different primers in combination with conventional resin cement and 10-methacryloyloxydecyl dihydrogen phosphate (MDP) containing self-adhesive resin cement without priming. Fully sintered high translucent zirconia samples (n = 160) were assigned into 2 groups of pre-treatments (n = 80): Alumina-sandblasting (AB) and Glass-bead (GB). Then, each group was divided into 4 sub-groups according to priming and cement used (n = 20 each): conventional self-adhesive resin cement, MDP-silane Primer, MDP primer both with conventional self-adhesive resin cement, and MDP contained cement. Shear bond strength (SBS) was measured after thermocycling. Failure mode was analyzed using stereomicroscope. Contact angle and surface topography were investigated using other fully sintered samples (n = 30) constructed for that sole purpose, divided into control (no pre-treatment [unmodified], alumina-, and glass-bead sandblasted groups). Two-way ANOVA was performed for SBS and failure mode was analyzed. The use of Alumina-sandblasting showed higher SBS compared to Glass-bead pre-treatment for MDP-silane primer (p = 0.034) and MDP primer (p < 0.001). While MDP contained cement showed higher but insignificant SBS when pre-treated with glass-beads. Alumina-sandblasting and glass-bead pre-treatments improve bond strength of zirconia combined using primers before cementation with conventional resin cement. Also, self-adhesive MDP contained cement along with surface pre-treatment showed the highest achievable bond strength. It was concluded that both alumina-sandblasting and glass-bead blasting improved SBS combined with MDP containing self-adhesive resin cement reducing the required clinical steps during cementation of zirconia restorations.

MDP-salts as an adhesion promoter with MDP-primers and self-adhesive resin cement for zirconia cementation.

PURPOSE: To evaluate the effect of zirconia priming with MDP-Salt before MDP containing primers and self-adhesive cement on the shear bond strength. MATERIALS AND METHODS: Fully sintered high translucent zirconia specimens (n = 120) were assigned into 2 groups (n = 60 each): Control (No Pretreatment) and Methacryloyloxydecyl dihydrogen phosphate salt (MDP-Salt) pretreated. Each group was divided into 3 subgroups (n = 20) according to cementation protocol: 1) MDP + Silane primer and conventional resin cement, 2) MDP+ Bisphenyl dimethacrylate (BPDM) primer and conventional resin cement, and 3) MDP containing self-adhesive resin cement. Shear bond strength (SBS) was measured after 10,000 thermocycling. Contact angle was measured for tested groups. Surface topography was assessed using a 3D confocal laser scanning microscope (CLSM). Weibull analysis was performed for SBS and one-way ANOVA for contact angle and surface topography measurements (α = 0.05). RESULTS: The use of MDP-Salt significantly improved the SBS (p < .05) for all tested subgroups. Self-adhesive cement showed an insignificant difference with MDP + Silane group for both groups (p > .05). MDP + BPDM showed a significantly lower characteristic strength compared to self-adhesive resin cement when both were pretreated with MDP-Salt. No difference between all tested groups in the surface topographic measurements while MDP-Salt showed the highest contact angle. CONCLUSION: MDP-Salt pretreatment can improve bonding performance between zirconia and MDP containing products.

Effect of silver diamine fluoride activation on bond strength to root dentin.

BACKGROUND: To investigate the effect of silver diamine fluoride (SDF) application and activation on the bond strength of gutta-percha to dentin and resin bonded post to dentin. METHODS: Thirty-six human premolar teeth were used. The coronal part tooth was removed, and endodontic mechanical preparation was performed for all the teeth. The teeth were divided according to final rinse protocol (n = 9) as follows: Control group; no SDF application, SDF/NA; 38% SDF as a final rinse with no activation, SDF/MDA; 38% SDF as a final rinse with manual dynamic activation and SDF/US; 38% SDF as a final rinse with ultrasonic activation. Root canal obturation using lateral condensation technique followed by fiber post insertion after 48 h in the root canal after corresponding preparations. The roots were cut with a low-speed precision saw creating 2 mm thickness sections. A total of 4 sections were obtained from each tooth, 2 coronal specimens (with post) and 2 apical specimens (with Gutta percha). Each specimen was subjected to push-out bond strength test with a universal testing machine. Data were analyzed using two-way ANOVA. RESULTS: The Push-out bond strength at the apical root section was significantly higher in SDF/MDA and SDF/US groups compared to control group. While for the coronal part, all SDF treated specimen showed reduced Push-out bond strength. CONCLUSION: SDF application as final rinse may reduce the bonding performance between fiber post and dentine. Activation with manual and ultrasonic methods improved the bond strength at the apical root section.

Novel Mediastinoscope-Assisted Minimally Invasive Esophagectomy for Esophageal Cancer: A Systematic Review and Meta-analysis.

BACKGROUND: Minimally invasive surgery is an expanding field of surgery that has replaced many open surgical techniques. Surgery remains a cornerstone in the treatment of esophageal cancer, yet it is still associated with significant morbidity and technical difficulties. Mediastinoscope-assisted esophagectomy is a promising technique that aims to decrease the surgical burden and enhance recovery. METHODS: PubMed, MEDLINE, and EMBASE databases were searched for publications on mediastinoscope-assisted esophagectomies for esophageal cancer. The primary endpoint was a postoperative anastomotic leak, while secondary endpoints were assessment of harvested lymph nodes (LNs), blood loss, chyle leak, hospital length of stay (LOS), operative (OR) time, pneumonia, wound infection, mortality, and microscopic positive margin (R1). The pooled event rate (PER) and pooled mean were calculated for binary and continuous outcomes respectively. RESULTS: Twenty-six out of the 2274 searched studies were included. The pooled event rate (PER) for anastomotic leak was 0.145 (0.1144; 0.1828). The PERs for chyle leak, recurrent laryngeal nerve injury/hoarseness, postoperative pneumonia, wound infection, early mortality, postoperative morbidity, and microscopically positive (R1) resection margins were 0.027, 0.185, 0.09, 0.083, 0.020, 0.378, and 0.037 respectively. The pooled means for blood loss, hospital stay, operative time, number of total harvested LNs, and number of harvested thoracic LNs were 159.209, 15.187, 311.116, 23.379, and 15.458 respectively. CONCLUSIONS: Mediastinoscopic esophagectomy is a promising minimally invasive technique, avoiding thoracotomy, patient repositioning, and lung manipulation; thus allowing for shorter surgery, decreased blood loss, and decreased postoperative morbidity. It can also be reliable in terms of oncological safety and LN dissection.