Bonding Strength of Lithium Disilicate Adhesive Crowns with Different Occluso-Cervical Preparation Heights and Cement Types

The aim of this study was to evaluate if adhesion technology with CAD/CAM can compensate for the reduction of occluso cervical preparation heights using different types of dental cement. The de-bonding failure types were then assessed. Here, 72 caries-free extracted human premolar teeth were prepared to have a remaining occlusal height of two, three, and four mm. IPS e.max lithium disilicate CAD/CAM crowns were cemented with adhesive resin cement Panavia SA, self-adhesive resin cement, RelyX Unicem Aplicap, and zinc phosphate cement. The cementation techniques were based on the manufacturer’s instructions. After thermocycling, all samples were tested for tensile bond strength via an Instron machine. One-way analysis of variance (ANOVA) with post hoc testing (P < 0.05) was performed. The means TBS for the two, three, and four-mm OCHP groups were 2.72±0.69, 3.06±0.82, and 3.25±0.79.0 MPa; ARC, SARC, and ZPC were 3.41±0.51, 3.45±0.41, 2.08±0.35 MPa, respectively with significant differences in both. The mixed cement had failures in the resin cement groups. Failure was predominantly cohesive in the zinc phosphate group. Resin cement had the highest SBS values versus ZPC values when both bonded to lithium disilicate crowns with different occlusal heights. The failure of the adhesive to the crown and/or to the tooth were the highest for the four types of resin cement. Around 25% were cohesive failures with resin cement, but this was predominately adhesive in crowns in zinc phosphate regardless of the preparation heights.

Effect of Enamel Pretreatment with Pastes Presenting Different Relative Dentin Abrasivity (RDA) Values on Orthodontic Bracket Bonding Efficacy of Microfilled Composite Resin: In Vitro Investigation and Randomized Clinical Trial

Bonding failure is a clinical issue frequently encountered in orthodontic practice. The aim of this study was to evaluate enamel pretreatment both in vitro and clinically using agents with different RDA values before brackets’ bonding, to assess if RDA can affect the Shear Bond Strength (SBS), Adhesive Remnant Index (ARI) and clinical failure rate of orthodontic brackets. For the in vitro study, 220 bovine teeth were pretreated with agents with different RDA values. Subsequently, brackets were bonded. For the clinical study, 20 patients underwent bonding of 20 brackets each with a split-mouth design. Low and high RDA toothpastes were used for enamel pretreatment. SBS, ARI and failures were recorded. Higher SBS values were found for teeth pretreated with lower RDA agents; conversely, lower SBS values were found for teeth pretreated with higher RDA agents (p < 0.05). For high ARI values, RDA increased too (p > 0.05). In the clinical study, a significantly lower failure rate was reported for teeth pretreated with low RDA toothpaste (2.5% in low RDA group, 7.0% in high RDA group; p < 0.05). No significant differences were assessed comparing the two dental arches and anterior and posterior sites. Enamel pretreatment with low RDA toothpastes could increase brackets’ survival rate. Further in vitro and clinical studies would be welcomed to confirm these findings.

Experimental study on mechanical behavior of orthotropic steel deck with adhesively bonded rigid pavement

The steel deck with rigid pavement has a lower risk of fatigue failure owing to the enhanced local rigidity. A reliable connection of steel plate and pavement and a convenient construction are critical concerns for this deck type. To seek a new application meeting the aforementioned requirements, this paper proposed a steel deck with adhesively bonded rigid pavement cast by non-reinforced ultra-high performance concrete (UHPC). To study the constructability and flexural properties of this deck type in a bridge deck system, four specimens including two with adhesively bonded connection and two reference ones with shear stud connection were fabricated and experimentally investigated by positive and negative bending tests. In addition, a simplified pretreatment of steel substrate was conducted before the application of epoxy resin to simulate the low quality of on-site construction. Experimental results indicate that the shear strength of the bonding connection with simplified steel pretreatment could decrease to half of that with strict preparation. Bending tests demonstrate that the adhesive bonding provides a more rigid connection between steel and concrete than shear studs did. The bonding failure load was 1.5 times the U-rib yielding load, indicating a high positive bending-carrying capacity of the deck. The adhesive provides better crack resistance than shear studs in negative bending. From a perspective on the bending behavior in the deck system, the adhesive bonding was reliable to obtain high bending capacities to resist actual vehicle loads. Besides, the non-uniform shrinkage of non-reinforced UHPC pavement can cause a 30% reduction of cracking strength.

Invisalign® vs. Spark™ Template: Which Is the Most Effective in the Attachment Bonding Procedure? A Randomized Controlled Trial

Aim: The primary aim of this randomized clinical trial was to evaluate the percentage of attachments’ debonding at the template’s removal both in Invisalign® and Spark™ systems. The secondary aim was to define the percentage of patients who did not show attachments’ debonding at the template’s removal. Materials and methods: Eighty patients who needed an orthodontic treatment were included in the study and randomly assigned to a treatment to be performed with Spark™ or Invisalign® clear aligners system. The patients were equally divided into two groups: Spark group (n = 40) and Invisalign group (n = 40). At the template removal by the teeth surface after the attachment bonding procedure, in each patient of both groups, it was assessed if some attachment debonding occurred and the number of attachments detached. Results: The Spark group showed, in general, a lower frequency in debonding in comparison with the Invisalign group, as 87.5% of patients in the Spark group did not show any bonding failure versus 27.5% in those of the Invisalign group. Conclusions: At template removal, the Spark™ template showed less attachment debonding compared to the Invisalign® template. The Spark™ template can be considered more effective in attachments’ transferring to the tooth surface than the Invisalign® one.

Investigation of Texture Effects at Interlayer Bonding Behavior Between AC Overlay on PCC

Slippage cracking in asphalt overlays occurs as a result of bonding failure between the AC and PCC layers. Direct shear test has been adopted to simulate the common and critical bonding failure. The effects of temperature and tack coat has already been studied by previous researchers, but the effects of texture were insufficiently considered. This study used the clamping shear strength to characterize the pure shear strength in pavement. It is defined as the difference between the total shear strength and the plain shear strength. The results showed that the interlayer behaved in an elastic manner at lower temperatures, generating brittle failures with cracking, whereas viscoelastic behavior dominated at higher temperatures, producing ductile failure that lead to slippage at the interface layer. Surface texture effects can be quantitatively characterized using clamping shear strength, and clamping shear strength can be used to optimize asphalt mixture in enhancing bonding performance.

Caring for Mothers: A Narrative Review on Interpersonal Violence and Peripartum Mental Health

Interpersonal violence in the perinatal period is frequent and should be considered a prominent health issue due to the risk of escalation of violence and the significant impact on mothers’ parenting after childbirth. Domestic violence during pregnancy can be associated with fatal and non-fatal adverse health outcomes due to the direct trauma to a pregnant woman’s body and to the effect of stress on fetal growth and development. Emotional violence is a risk factor for prenatal and/or postpartum depression. Recent studies focusing on abusive situations during peripartum and possible preventive strategies were identified in PubMed/Medline, Scopus, Embase, and ScienceDirect. All of the available literature was retrospectively reviewed with a special attention to peer-reviewed publications from the last ten years. Results of the present narrative review suggest that perinatal health care professionals (general practitioners, gynecologists, obstetricians, psychologists, psychiatrists) should promptly detect interpersonal violence during and after pregnancy and provide health care for pregnant women. It seems pivotal to guarantee psychological care for abused women before, during, and after pregnancy in order to prevent the risk of depressive symptoms, other mental or physical sequelae, and mother-to-infant bonding failure. There is an urgent need for multifaceted interventions: programs should focus on several risk factors and should design tailored care pathways fitted to the specific needs of women and finalized to support them across the lifespan.

Experimental behavior of injected geopolymer grout using styrene-butadiene latex for the repair and strengthening of masonry walls

Unreinforced masonry buildings in the historic centers of the world have often been overlooked for centuries without any protection. These buildings demonstrate low resistance under external effects, especially against earthquakes. Earthquakes cause serious damage to the buildings and even the collapse of structures as a result of seismic stimulation from the impact of pounding with structural impacts. For this reason, it is of great importance to repair and strengthen damaged masonry structures. This study investigated the testing of masonry wall specimens produced from different kinds of masonry units with various types of mortar. Then, geopolymer grouts with high mechanical properties were produced by using alkali activation and industrial products. The experimental performance of strengthened masonry wall samples was determined using the optimum geopolymer grout in vertical compression tests. The behavior, failure mode, and crack pattern of the masonry wall samples were determined under loading systems. Experimental results demonstrate that the use of additive styrene-butadiene (SB) latex geopolymer grouts on damaged walls increased the load-carrying capacity and ductility significantly compared to the corresponding values of samples before initial failure. All of the strengthened walls failed through the de-bonding failure mode, and no visible damage was observed on the samples. Consequently, geopolymer grouts displayed many advantages over conventional repair materials due to their high viscosity, compressive strength, eco-friendliness, and excellent resistance.

A Retrospective Clinical Audit of Bracket Failure among Patients Undergoing Orthodontic Therapy

Objective. Bonding failure is a problem in orthodontic therapy and has been associated with orthodontic emergencies and delayed treatment time. The aim of this study is to determine the bracket failure rate among patients undergoing orthodontic therapy. Materials and Methods. From the archives of posttreatment records, 200 total cases were selected, out of which 122 cases had detailed treatment records. Cases with incomplete records, large restorations, or enamel aberrations were excluded from the study. Descriptive statistics were applied to obtain sample characteristics, and a chi-square test was applied to compare the bracket failure between different categories. Result. Out of the 122 samples enrolled in the study, female and male patients comprised 71% and 29%, respectively. Class I malocclusions were the most common problem (56%), followed by Class II (41%) and Class III (3%). The bracket failure rate was 3.43%, and 32% of the patients had an incidence of bracket failure. There was no significant difference in bracket failure among genders ( p = 0.344 ), malocclusion types ( p = 0.191 ), or operators ( p = 0.188 ). The maxillary left quadrant was the most common site of bracket failure, followed by the mandibular right quadrant. Conclusion. Bracket failure is relatively uncommon. It is not affected by the gender or age of the patient or by malocclusion type. The maxillary left and mandibular right quadrants are the most common sites of bracket failure.