Load-bearing capacity of pressable lithium disilicates applied as ultra-thin occlusal veneers on molars.

PURPOSE The aim was to investigate the load bearing capacity of different pressable lithium disilicates cemented as occlusal veneers on molars. MATERIALS AND METHODS One control group and six test groups were formed consisting of 20 specimens each (n = 20). The six test groups differed in the utilizing pressable lithium disilicate to fabricate occlusal veneers. As a control group, "group Lis", the lithium disilicate with the highest reported flexural strength was used (initial LiSi Press, GC Europe; Leuven, Belgium / flexural strength: 508 MPa). The test groups consisted of other pressable lithium disilicates with lower flexural strength values: "Ema" (IPS e.max press), "Vit" (VITA Ambria), "Liv" (Livento Press), "Amb" (Amber Press), "Mas" (Amber Press Master) and "Ros" (Rosetta SP)". After the preparation of 140 extracted human molars, which included the removal of the central enamel, the specimens were scanned using a desktop scanner. With the aid of a design software, the occlusal veneers were designed in a standardized thickness of 0.5 mm. To fabricate the restorations, all tested materials were processed using heat-pressing technique. All restorations were adhesively cemented. Afterwards, the specimens underwent cyclic fatigue during an aging procedure in a chewing simulator (1'200'000 chewing-cycles, 49 N force, 5-55°C temperature changes). Subsequently, the specimens were statically loaded and the load which was necessary to fracture the specimen (Fmax) were measured. Differences between the groups were compared applying the Kruskal-Wallis (KW) test and the Wilcoxon-Mann-Whitney-Test (WMW: p < 0.05). The two-parameter Weibull distribution values were calculated. RESULTS The fatigue resistance was 100% for the groups Lis, Vit, Liv, Amb, Mas and Ros, whereas the group Ema showed a fatigue resistance of 95%. The control group Lis showed median Fmax values of 2'328 N. The median Fmax values for the test groups ranged between 1'753 N (Vit) and 2'490 N (Ros). Statistically significant difference was observed among the groups Lis (control) and Vit (KW: p < 0.001). Weibull distribution presented the highest shape values for the group Ros (12.83) and the lowest values for the group Ema (4.71). CONCLUSION Regarding their load-bearing capacity different pressable lithium disilicates can be recommended to fabricate ultra-thin occlusal veneers on molars when restoring occlusal tooth wear

Effekt von SnCl2/AmF-Vorbehandlung auf die Dentinhaftkraft bei erodiertem Dentin

Zielsetzung: Das Ziel der vorliegenden Studie war, die Wirkung der SnCl2/AmF-Vorbehandlung auf die Dentinhaftkraft von Komposit auf erodiertem Dentin - vermittelt durch die Adhäsivsysteme Clearfil SE oder Scotchbond Universal - zu prüfen. Materialien und Methoden: Aus extrahierten menschlichen Molaren wurden 160 Dentinprobekörper hergestellt (n=20 pro Gruppe; 8 Gruppen) und standardisiert aufgeraut. Die Hälfte der Dentinprobekörper unterlag danach einer artifiziellen Erosion mittels Durchlaufen von Demineralisations- und Remineralisationszyklen. Anschliessend wurden die Dentinprobekörper vorbehandelt und restauriert: Die Hälfte der Dentinprobekörper wurde mit SnCl2/AmF vorbehandelt und dann mit Clearfil SE oder Scotchbond Universal konditioniert. Die andere Hälfte der Dentinprobekörper wurde ohne weitere Vorbehandlung mit Clearfil SE oder Scotchbond Universal konditioniert. Die Restauration erfolgte bei allen Dentinprobekörpern mit demselben Komposit (Clearfil Majesty Esthetic). Die restaurierten Dentinprobekörper wurden nach 24 h in Stäbchen gesägt, durch Zug zum Bruch gebracht (Mikrozughaftkraft-Test (microtensile bond strength test, „µTBS-test“)); die Dentinhaftkraft (MPa) wurde gemessen und die Bruchmuster wurden bestimmt. Die Werte der Dentinhaftkraft wurden mittels nichtparametrischer ANOVA gefolgt von Mann-Whitney-U-Tests statistisch analysiert. Die Beurteilung der Bruchmuster wurde deskriptiv ausgewertet. Resultate: Die artifizielle Erosion führte bei den Dentinprobekörpern zu signifikant tieferer Dentinhaftkraft (p˂0.0001). Die Vorbehandlung mit SnCl2/AmF führte zu keinem signifikanten Unterschied bezüglich Dentinhaftkraft. Auch bestand kein signifikanter Unterschied der Dentinhaftkraft zwischen den beiden verwendeten Adhäsivsystemen Clearfil SE und Scotchbond Universal. Schlussfolgerung: Die Dentinhaftkraft von Komposit auf erodiertem Dentin vermittelt durch ein Adhäsivsystem war niedriger als auf nicht erodiertem Dentin. Die Dentinhaftkraft wurde durch die Vorbehandlung mit SnCl2/AmF nicht beeinflusst. Die beiden Adhäsivsysteme Clearfil SE und Scotchbond Universal führten zur selben, hohen Dentinhaftkraft

Green oxidation catalysts: computational design of high-efficiency models of galactose oxidase

Ab initio calcns. were used for the rational design of efficient alc. oxidn. catalysts that mimic the enzyme galactose oxidase. Different ligand substitutions were explored based on natural (copper, depicted) and alternative (rhodium) metal redox centers. The calcd. turnover rate for the most efficient copper-based biomimetic compd. is greater than that of the natural enzyme. [on SciFinder (R)

The Effect of SnCl/AmF Pretreatment on Short- and Long-Term Bond Strength to Eroded Dentin.

This study investigated the effect of SnCl/AmF pretreatment on short- and long-term bond strength of resin composite to eroded dentin mediated by two self-etch, MDP-containing adhesive systems. 184 dentin specimens were produced from extracted human molars. Half the specimens ( = 92) were artificially eroded, and half were left untreated. For both substrates, half the specimens were pretreated with SnCl/AmF, and half were left untreated. The specimens were treated with Clearfil SE Bond or Scotchbond Universal prior to application of resin composite. Microtensile bond strength (TBS) was measured after 24 h or 1 year. Failure mode was detected and EDX was performed. TBS results were statistically analyzed ( = 0.05). TBS was significantly influenced by the dentin substrate (eroded 1 year; < 0.0001) but not by pretreatment with SnCl/AmF or adhesive system. The predominant failure mode was adhesive failure at the dentin-adhesive interface. The content of Sn was generally below detection limit. Pretreatment with SnCl/AmF did not influence short- and long-term bond strength to eroded dentin. Bond strength was reduced after storage for one year, was lower to eroded dentin than to noneroded dentin, and was similar for the two adhesive systems

Load-bearing capacity of pressable lithium disilicates applied as ultra-thin occlusal veneers on molars

PURPOSE: The aim was to investigate the load bearing capacity of different pressable lithium disilicates cemented as occlusal veneers on molars. MATERIALS AND METHODS: One control group and six test groups were formed consisting of 20 specimens each (n = 20). The six test groups differed in the utilizing pressable lithium disilicate to fabricate occlusal veneers. As a control group, "group Lis", the lithium disilicate with the highest reported flexural strength was used (initial LiSi Press, GC Europe; Leuven, Belgium / flexural strength: 508 MPa). The test groups consisted of other pressable lithium disilicates with lower flexural strength values: "Ema" (IPS e.max press), "Vit" (VITA Ambria), "Liv" (Livento Press), "Amb" (Amber Press), "Mas" (Amber Press Master) and "Ros" (Rosetta SP)". After the preparation of 140 extracted human molars, which included the removal of the central enamel, the specimens were scanned using a desktop scanner. With the aid of a design software, the occlusal veneers were designed in a standardized thickness of 0.5 mm. To fabricate the restorations, all tested materials were processed using heat-pressing technique. All restorations were adhesively cemented. Afterwards, the specimens underwent cyclic fatigue during an aging procedure in a chewing simulator (1'200'000 chewing-cycles, 49 N force, 5-55°C temperature changes). Subsequently, the specimens were statically loaded and the load which was necessary to fracture the specimen (F$_{max}$) were measured. Differences between the groups were compared applying the Kruskal-Wallis (KW) test and the Wilcoxon-Mann-Whitney-Test (WMW: p < 0.05). The two-parameter Weibull distribution values were calculated. RESULTS: The fatigue resistance was 100% for the groups Lis, Vit, Liv, Amb, Mas and Ros, whereas the group Ema showed a fatigue resistance of 95%. The control group Lis showed median F$_{max}$ values of 2'328 N. The median F$_{max}$ values for the test groups ranged between 1'753 N (Vit) and 2'490 N (Ros). Statistically significant difference was observed among the groups Lis (control) and Vit (KW: p < 0.001). Weibull distribution presented the highest shape values for the group Ros (12.83) and the lowest values for the group Ema (4.71). CONCLUSION: Regarding their load-bearing capacity different pressable lithium disilicates can be recommended to fabricate ultra-thin occlusal veneers on molars when restoring occlusal tooth wear

Cement pressurizing reduces radiolucent lines at glenoid: A randomized, multicentric study.

Background The hypothesis of this study is that cement pressurization into the glenoid reduces the rate of radiolucent lines in total shoulder arthroplasty in the mean 25.5 months after the operation. Methods To examine this effect, a multicentric prospective randomized study (level of evidence 1) was initiated: one group (group P, n = 24) received intraoperative pressurization of cement into the cancellous bone of the glenoid, the other cement without pressure (group NoP, n = 27). Inclusion criteria were an osteoarthritis with glenoid erosion <15° and an intact rotator cuff. Results There were no significant differences preoperatively between the groups regarding age (mean age 66 ± 10 years (range 44-81)), gender, range of motion, scores and pathomorphology. Both groups had a significant improvement of the scores, strength, motion and satisfaction 25.5 months after the intervention. The scores were similar between the groups (ns). However, cement pressurization at the glenoid side significantly reduced the incidence of radiolucent lines (p < 0.027). Conclusion This supports the use of this simple technique to improve long-term survival of total shoulder arthroplasty.Level of evidence: 1

Functional and Radiologic Outcomes of Degenerative Versus Traumatic Full-Thickness Rotator Cuff Tears Involving the Supraspinatus Tendon.

BACKGROUND Arthroscopic rotator cuff repair (ARCR) is among the most commonly performed orthopaedic procedures. Several factors-including age, sex, and tear severity-have been identified as predictors for outcome after repair. The influence of the tear etiology on functional and structural outcome remains controversial. PURPOSE To investigate the influence of tear etiology (degenerative vs traumatic) on functional and structural outcomes in patients with supraspinatus tendon tears. STUDY DESIGN Cohort study; Level of evidence, 2. METHODS Patients undergoing ARCR from 19 centers were prospectively enrolled between June 2020 and November 2021. Full-thickness, nonmassive tears involving the supraspinatus tendon were included. Tears were classified as degenerative (chronic shoulder pain, no history of trauma) or traumatic (acute, traumatic onset, no previous shoulder pain). Range of motion, strength, the Subjective Shoulder Value, the Oxford Shoulder Score (OSS), and the Constant-Murley Score (CMS) were assessed before (baseline) and 6 and 12 months after ARCR. The Subjective Shoulder Value and the OSS were also determined at the 24-month follow-up. Repair integrity after 12 months was documented, as well as additional surgeries up to the 24-month follow-up. Tear groups were compared using mixed models adjusted for potential confounding effects. RESULTS From a cohort of 973 consecutive patients, 421 patients (degenerative tear, n = 230; traumatic tear, n = 191) met the inclusion criteria. The traumatic tear group had lower mean baseline OSS and CMS scores but significantly greater score changes 12 months after ARCR (OSS, 18 [SD, 8]; CMS, 34 [SD,18] vs degenerative: OSS, 15 [SD, 8]; CMS, 22 [SD, 15]) (P < .001) and significantly higher 12-month overall scores (OSS, 44 [SD, 5]; CMS, 79 [SD, 9] vs degenerative: OSS, 42 [SD, 7]; CMS, 76 [SD, 12]) (P≤ .006). At the 24-month follow-up, neither the OSS (degenerative, 44 [SD, 6]; traumatic, 45 [SD, 6]; P = .346) nor the rates of repair failure (degenerative, 14 [6.1%]; traumatic 12 [6.3%]; P = .934) and additional surgeries (7 [3%]; 7 [3.7%]; P = .723) differed between groups. CONCLUSION Patients with degenerative and traumatic full-thickness supraspinatus tendon tears who had ARCR show satisfactory short-term functional results. Although patients with traumatic tears have lower baseline functional scores, they rehabilitate over time and show comparable clinical results 1 year after ARCR. Similarly, degenerative and traumatic rotator cuff tears show comparable structural outcomes, which suggests that degenerated tendons retain healing potential

Differential Expression of Receptor Tyrosine Kinases (RTKs) and IGF-I Pathway Activation in Human Uterine Leiomyomas

Uterine leiomyomas (fibroids) are benign tumors that are prevalent in women of reproductive age. Research suggests that activated receptor tyrosine kinases (RTKs) play an important role in the enhanced proliferation observed in fibroids. In this study, a phospho-RTK array technique was used to detect RTK activity in leiomyomas compared with myometrial tissue. We found that fifteen out of seventeen RTKs evaluated in this study were highly expressed (P < 0.02–0.03) in the leiomyomas, and included the IGF-I/IGF-IR, EGF/EGFR, FGF/FGF-R, HGF/HGF-R, and PDGF/PDGF-R gene families. Due to the higher protein levels of IGF-IR observed in leiomyomas by us in earlier studies, we decided to focus on the activation of the IGF-IR, its downstream effectors, and MAPKp44/42 to confirm our earlier findings; and validate the significance of the increased IGF-IR phosphorylation observed by RTK array analysis in this study. We used immunolocalization, western blot, or immunoprecipitation studies and confirmed that leiomyomas overexpressed IGF-IRβ and phosphorylated IGF-IRβ. Additionally, we showed that the downstream effectors, Shc, Grb2, and MAPKp44/42 (P < 0.02–0.001) were also overexpressed and involved in IGF-IR signaling in these tumors, while IRS-I, PI3K, and AKT were not. In vitro studies showed that IGF-I (100 ng/mL) increased the proliferation of uterine leiomyoma cells (UtLM) (P < 0.0001), and that phosphorylated IGF-IRβ, Shc, and MAPKp44/42 were also overexpressed in IGF-I-treated UtLM cells (P < 0.05), similar to the tissue findings. A neutralizing antibody against the IGF-IRβ blocked these effects. These data indicate that overexpression of RTKs and, in particular, activation of the IGF-IR signaling pathway through Shc/Grb2/MAPK are important in mediating uterine leiomyoma growth. These data may provide new anti-tumor targets for noninvasive treatment of fibroids

Swiss-wide multicentre evaluation and prediction of core outcomes in arthroscopic rotator cuff repair: protocol for the ARCR_Pred cohort study

Introduction In the field of arthroscopic rotator cuff repair (ARCR), reporting standards of published studies differ dramatically, notably concerning adverse events (AEs). In addition, prognostic studies are overall methodologically poor, based on small data sets and explore only limited numbers of influencing factors. We aim to develop prognostic models for individual ARCR patients, primarily for the patient-reported assessment of shoulder function (Oxford Shoulder Score (OSS)) and the occurrence of shoulder stiffness 6 months after surgery. We also aim to evaluate the use of a consensus core event set (CES) for AEs and validate a severity classification for these events, considering the patient’s perspective.Methods and analysis A cohort of 970 primary ARCR patients will be prospectively documented from several Swiss and German orthopaedic clinics up to 24 months postoperatively. Patient clinical examinations at 6 and 12 months will include shoulder range of motion and strength (Constant Score). Tendon repair integrity status will be assessed by ultrasound at 12 months. Patient-reported questionnaires at 6, 12 and 24 months will determine functional scores (subjective shoulder value, OSS), anxiety and depression scores, working status, sports activities, and quality of life (European Quality of Life 5 Dimensions 5 Level questionnaire). AEs will be documented according to a CES. Prognostic models will be developed using an internationally supported regression methodology. Multiple prognostic factors, including patient baseline demographics, psychological, socioeconomic and clinical factors, rotator cuff integrity, concomitant local findings, and (post)operative management factors, will be investigated.Ethics and dissemination This project contributes to the development of personalised risk predictions for supporting the surgical decision process in ARCR. The consensus CES may become an international reference for the reporting of complications in clinical studies and registries. Ethical approval was obtained on 1 April 2020 from the lead ethics committee (EKNZ, Basel, Switzerland; ID: 2019-02076). All participants will provide informed written consent before enrolment in the study.Trial registration number NCT04321005.Protocol version Version 2 (13 December 2019)