Do zirconia single-retainer resin-bonded fixed dental prostheses present a viable treatment option for the replacement of missing anterior teeth? A systematic review and meta-analysis.

STATEMENT OF PROBLEM: Zirconia has been widely used in restorative dentistry because of its favorable strength and esthetics. However, its polycrystalline structure presents a challenge for resin bonding. Significant research into surface treatments of zirconia to improve bonding has been reported, yet a universally accepted protocol remains elusive. PURPOSE: The purpose of this systematic review and meta-analysis was to evaluate the performance of anterior single-retainer zirconia resin-bonded fixed dental prostheses (RBFDPs) and review the bonding protocols used in the published data. MATERIAL AND METHODS: An electronic search of English language literature was conducted in the PubMed and Ovid (MEDLINE) databases. Following the application of inclusion and exclusion criteria, the research was evaluated to assess the quantitative data. RESULTS: Of the included studies, 1 randomized controlled trial, 3 prospective cohort studies, and 2 retrospective cohort studies reporting on anterior single-retainer zirconia RBFDPs were evaluated. Over a 3- to 10-year period, the success rate of anterior single-retainer zirconia RBFDPs was over 80%. Although there were reports of debonds, this is a minor complication as rebonding is usually possible. Furthermore, catastrophic fractures of the entire prosthesis were rare. CONCLUSIONS: Evidence for the use of single-retainer zirconia RBFDPs as a suitable treatment option for the replacement of anterior missing teeth is considerable. Based on the findings of this systematic review and meta-analysis, a 2-step process comprising micromechanical retention using airborne-particle abrasion and subsequent resin-zirconia adhesion by the application of 10-methacryloyloxydecyl dihydrogen phosphate (10-MDP) can be recommended.

New Tetra-Schiff Bases as Efficient Photostabilizers for Poly(vinyl chloride).

Three new tetra-Schiff bases were synthesized and characterized to be used as photostabilizers for poly(vinyl chloride) (PVC) films. The photostability of PVC films (40 µm thickness) in the presence of Schiff bases (0.5 wt %) upon irradiation (300 h) with a UV light (λmax = 365 nm and light intensity = 6.43 × 10-9 ein∙dm-3∙s-1) was examined using various spectroscopic measurements and surface morphology analysis. The changes in various functional groups' indices, weight and viscosity average molecular weight of PVC films were monitored against irradiation time. The additives used showed photostability for PVC films, with Schiff base 1 being the most effective additive upon irradiation, followed by 2 and 3. The atomic force microscopy (AFM) images for the PVC surface containing Schiff base 1 after irradiation were found to be smooth, with a roughness factor (Rq) of 36.8, compared to 132.2 for the PVC (blank). Several possible mechanisms that explain PVC photostabilization upon irradiation in the presence of tetra-Schiff bases were proposed.

Polyphosphates as Inhibitors for Poly(vinyl Chloride) Photodegradation.

Three polyphosphates were used as inhibitors for poly(vinyl chloride) (PVC) photodegradation. The polyphosphates were added to PVC at a concentration of 0.5% by weight. The PVC films (40 µm thickness) were irradiated at room temperature with ultraviolet (UV) light for up to 300 h. The changes in PVC films after irradiation were monitored by Fourier transform infrared spectroscopy, weight loss, viscosity-average molecular weight determination, and atomic force microscopy. These changes were very noticeable in the blank PVC films compared to the ones obtained when additives were used. The polyphosphates can inhibit the PVC photodegradation through direct absorption of UV light, interactions with PVC chains, and acting as radical scavengers.

Neuraxial labor analgesia in a parturient with carnitine palmitoyl transferase type II deficiency: a case report.

Carnitine Palmitoyl Transferase Type II (CPT II) deficiency is a disorder of fatty acid beta oxidation that causes decreased adenosine triphosphate (ATP) and ketone production during periods of fasting or high energy requirements. Labor and delivery can precipitate attacks for parturients with this disorder, causing hypoglycemia, muscle weakness, rhabdomyolysis, and kidney failure. Anesthetic management considers the delivery mode and anesthetic medications available to reduce these risks. We present the case of a pregnant patient with CPT II deficiency with labor epidural analgesia and a vaginal delivery, with alternative plans had a different delivery mode been required.

Autogenous dentin graft versus alloplastic graft combined with socket shield for pre-implant socket preservation: a split-mouth randomized clinical trial.

After tooth extraction, alveolar bone resorption and labial bone plate thinning occur due to the lack of periodontal ligaments. The socket shield method was developed to preserve the alveolar ridge. A split-mouth study was performed in which eight patients were treated using alloplast with socket shield on one side (alloplast group, control) and autogenous dentin graft with socket shield on the contralateral side (dentin group, test). After 3 months, a trephine bone core was collected from all sites and evaluated by histological, histomorphometric, and radiographic analysis. Thin bony trabeculae were formed surrounding the residual alloplast, while thicker trabeculae of bone formed and fused to the autogenous dentin. The percentage of newly formed bone was significantly higher in the dentin group when compared to the alloplast group (P = 0.020). Radiographically, there was no significant difference in the mean percentage increase in bone density from preoperative to post-grafting between the two groups. Moreover, when comparing the change in labial bone level from preoperative to 3 months post-grafting between the two groups, there was no significant difference. The autogenous dentin graft combined with socket shield could be a promising technique for socket preservation.

2-(1,3-Dioxoisoindolin-2-yl)acetic acid-N'-[(E)-4-meth-oxy-benzyl-idene]pyridine-4-carbohydrazide (2/1).

In the crystal structure of the title compound, 2C(10)H(7)NO(4)·C(14)H(13)N(3)O(2), the two independent acid mol-ecules are connected through strong O-H⋯N and O-H⋯O hydrogen bonds to the central mol-ecule of the anti-tubercular drug N'-[(E)-4-meth-oxy-benzyl-idene]pyridine-4-carbohydrazide. Two such trimolecular units related by an inversion centre inter-act through a pair of N-H⋯O hydrogen bonds, forming a 3 + 3 mol-ecular aggregate. The dihedral angle between the aromatic rings of the hydrazone mol-ecule is 1.99 (12)°. The crystal packing features weak C-H⋯O and π-π stacking inter-actions, with centroid-centroid distances of 3.8460 (19) and 3.8703 (13) Å.

Large branchial arch cyst excision using superficial and deep cervical plexus blocks in a patient with severe comorbidities.

Branchial arches are embryologic structures that develop between the fourth and seventh gestational week. Anomalies may form if these structures fail to develop. The majority of cases are diagnosed during childhood, with surgical excision recommended to prevent risk of infection, growth or malignancy. We report an unusual case of a 72-year-old man with severe cardiac comorbidities who presented with a large second branchial arch cyst extending into the oropharynx. General anaesthesia to facilitate surgical excision was deemed too risky. Therefore, we performed successful ultrasound-guided superficial and deep cervical plexus blocks as a sole mode of anaesthesia. This case highlights how regional anaesthesia can be utilised to facilitate surgery in high-risk patients, as well as presenting an alternative for general anaesthesia.

Structure of smectic-A liquid crystals in nonuniform domains: Modeling the impact of imperfect boundaries.

This paper describes the construction of equilibrium configurations for smectic-A liquid crystals subjected to nonuniform physical boundary conditions, with two-dimensional dependence on the director and layer normal, and a nonlinear layer function. Euler-Lagrange equations are constructed that describe key properties of liquid crystals confined between two boundaries exhibiting spatial imperfections. The results of the model are shown to be consistent with previous published findings in simple domains while results are obtained on how the structure of the liquid crystals changes in response to boundary perturbations. Domain sizes are considered representing those currently used in applications while predictions in smaller domains at the limit of current technologies are also made. In particular, it is shown that the curvature along a boundary impacts on the liquid crystal's structure distant from the boundary feature and therefore previously developed mathematical models, that essentially reduced the problem to a single spatial dimension, cannot be used in such circumstances. Consequences for practical applications are briefly discussed.

The effect of high UV radiation exposure environment on the novel PVC polymers.

Although plastic induces environmental damages, almost the consumption of poly(vinyl chloride) never stops increasing. Therefore, this work abstracted by two parts, first, synthesis of Schiff bases 1-4 compounds through the reaction of amino group with appropriate aromatic aldehyde, reaction of PVC with Schiff bases compounds 1-4 in THF to form a new modified PVC-1, PVC-2, PVC-3, and PVC-4. The structures of Schiff bases 1-4 and the modified PVC-1, PVC-2, PVC-3, and PVC-4 have been characterized by different spectroscopic analyses. Second, the influence of introducing 4-amino-1,2,4-triazole as a pendent groups into PVC chain investigated on photostability rules of tests. The modified polymers photostability investigated by observing indices (ICO, Ipo, and IOH), weight loss, UV and morphological studies, and all results obtained indicated that PVC-1, PVC-2, PVC-3 and PVC-4 gave lower growth rate of ICO, IPO, and IOH through UV exposure time. The photostability are given as PVC-4 < PVC-3 < PVC-2 < PVC-1 from different mechanisms which suggested building on existence of 4-amino-1,2,4-triazole moieties in the polymer chain.

Radiographic Misdiagnoses After Periurethral Bulking Agents.

OBJECTIVES: Injectable urethral bulking agents are commonly used to manage stress urinary incontinence. Urologic or other symptoms may prompt pelvic imaging at a later date, when bulking agents may be visualized and incorrectly interpreted. Our goal was to evaluate the incidence of misdiagnosis and which pathologies were the most common misinterpretations and their frequency. METHODS: All records were reviewed for patients who underwent periurethral injection for stress urinary incontinence for pelvic imaging after treatment from 2005 to 2015. Radiological reports were reviewed for any description potentially related to injection therapy, and descriptive statistics performed. RESULTS: A total of 528 patients underwent injection of a urethral bulking agent. Of these, 79 patients (15%) had a total of 111 additional abdominal or pelvic imaging studies performed with abnormal periurethral findings mentioned. Thirty-nine (35%) of 111 studies were correctly interpreted as urethral bulking agents, and in 72 (65%) of 111 studies, the urethral bulking agents were not correctly identified. The most common misdiagnoses were bladder calcification (26; 23%), urethral diverticulum with stone (12; 11%), periurethral calcification (9; 8%), unknown pelvic density (8; 7%), and mass suspicious for malignancy (6; 5%). CONCLUSIONS: Urethral bulking agents commonly were not mentioned on subsequent imaging but, when commented on, were misinterpreted 65% of the time including worrisome pathologies (diverticulum with stone, unknown mass, and malignancy), requiring subsequent evaluation and potentially procedural/surgical management. It is critical for the ordering clinician to inform the radiologist of this history and for radiologists to consider bulking agents in the differential diagnosis of radiographic findings in this location.

SEM analysis of the tunable honeycomb structure of irradiated poly(vinyl chloride) films doped with polyphosphate.

The fabrication of tunable poly(vinyl chloride) porous films containing polyphosphate as an additive was successful. Irradiation of poly(vinyl chloride) films containing polyphosphate at a low concentration (0.5% by weight) with an ultraviolet light (λmax = 313 nm) for 300 h leads to the formation of a honeycomb like structure. The scanning electron microscopy images, at different magnification power, confirmed the production of the PVC honeycomb-like structure. The morphological images of the polymeric film showed a rough surface and a large number of regularly distributed hexagonal pores. The number of pores increased upon irradiation time and it was maximum after 300 h. The honeycomb structure formation could be due to the regular aggregation of polyphosphate among the polymeric chains, the increase in solution intrinsic viscosity and evaluation of hydrogen chloride gas through dehydrochlorination process.

Fabrication of Novel Ball-Like Polystyrene Films Containing Schiff Base Microspheres as Photostabilizers.

Polystyrene films containing a low concentration of three highly aromatic Schiff bases were prepared using the casting method. The polystyrene films were irradiated with ultraviolet light (300 h). The polystyrene infrared spectra, weight loss, molecular weight reduction and the surface morphology were examined upon irradiation. The Schiff bases acted as photostabilizers and reduced the photodegradation of polystyrene films to a significant level in comparison to the blank film. The images recorded of the surface of the miscible polystyrene/Schiff base blends showed novel ball-like microspheres with a diameter of 3.4⁻4.3 µm. The Schiff bases were able to endow excellent protection to polystyrene against ultraviolet irradiation.

New Eco-Friendly Phosphorus Organic Polymers as Gas Storage Media.

Three phosphate esters 1⁻3 were successfully synthesized from the reaction of 2-, 3- and 4-hydroxybenzaldehyde with phosphoryl chloride. Reactions of 1⁻3 with benzidine in the presence of glacial acetic acid gave the corresponding novel phosphorus organic polymers 4⁻6 containing the azomethane linkage. The structures of the synthesized compounds were confirmed by Fourier transform infrared spectroscopy, nuclear magnetic resonance and elemental analysis. Interesting physiochemical properties for the polymeric materials 4⁻6 were observed using a combination of several techniques such as gel permeation chromatography, scanning electron microscopy, Brunauer⁻Emmett⁻Teller and nitrogen adsorption⁻desorption isotherm, Barrett⁻Joyner⁻Halenda and H-sorb 2600 analyzer. The mesoporous polymers 4⁻6 exhibit tunable porosity with Brunauer⁻Emmett⁻Teller surface area (SABET = 24.8⁻30 m²·g⁻1), pore volume (0.03⁻0.05 cm³·g⁻1) and narrow pore size distribution, in which the average pore size was 2.4⁻2.8 nm. Polymers 4⁻6 were found to have high gas storage capacity and physico-chemical stability, particularly at a high pressure. At 323 K and 50 bars, polymers 4⁻6 have remarkable carbon dioxide uptake (up to 82.1 cm³·g⁻1) and a low hydrogen uptake (up to 7.4 cm³·g⁻1). The adsorption capacity of gasses for polymer 5 was found to be higher than those for polymers 4 and 6.

ATP enhances cyclic AMP accumulation by intact P388 mouse lymphoma cells.

One of the characteristics of malignant cells is a poor response to hormones and a low level of cyclic AMP. Whilst this is true of intact P388 mouse lymphoma cells, high levels of adenylate cyclase (ATP pyrophosphate-lyase (cyclizing), EC 4.6.1.1) activity can be measured in particulate preparations of these cells. When ATP is added to the incubation medium of intact lymphoma cells, the cyclic AMP level is enhanced. This effect of ATP is not mediated by adenosine, nor is it enhanced by NaF. The ATP content of the lymphoma cells is much lower than that of CH23 Chinese hamster fibroblast and PCM3 hybrid cells, whose cyclic AMP levels are not affected by the presence of ATP. This suggests that adenylate cyclase, in the lymphoma cells, is bathed in a pool which is deficient in substrate. The substrate concentration of this pool is thought to be elevated by addition of ATP to the incubation medium with ATP, itself, crossing the plasma membrane.

Trypsin modifies the activity of adenylate cyclase from normal, malignant and hybrid mammalian cells.

Adenylate cyclase (ATP pyrophosphate-lyase (cylizing), EC 4.6.1.1) activity, measured in homogenates of normal, malignant and hybrid mammalian cell lines, is enhanced and subsequently inhibited by increasing concentrations of trypsin (EC 3.4.21.4). Treatment of intact cells with trypsin appears to cause latent activation of adenylate cyclase (i.e. activation which is only expressed after homogenization of the cells). Conversely, adenylate cyclase activity of a normal Chinese hamster fibroblast cell line is inhibited in intact cells by trypsin through the degradation of some site on the outer surface of the plasma membrane. The prostaglandin E1 receptor is not affected by trypsinization of cells.

Trabecular bone formation in the healing of the rodent molar tooth extraction socket.

The aim of this study was to investigate the nature of the template structure on which trabecular bone formation occurs during healing of the rodent tooth extraction socket, a well studied bone healing system. The presence of collagen type II mRNA has previously been described in the healing socket, although the formation of the protein or cartilage has not been observed. However, recent evidence from developmental and other bone healing studies indicates that collagen type III may be important in forming the preliminary scaffold on which bone trabeculae are formed. The maxillary right molar teeth were removed from rats under general anaesthesia and the animals killed at various times afterward. The tissues were examined using histological, in situ hybridization, and immunohistochemical staining techniques. It was concluded that collagen type IIA mRNA was produced by osteoblast cells of the socket, but that collagen type II, if present, would account for less than 0.01% of the total proteins extracted. During bone formation, Sharpey's fibers were seen radiating from the peripheral bone toward the center of the socket. These optically active collagen fibers were inserted into the forming bone trabeculae and were recognized by antibodies raised against collagen type III. The arrangement and composition of these fibers therefore suggest that they form a preliminary framework on which deposition of woven bone trabeculae occurs.

A novel cell culture model of chondrocyte differentiation during mammalian endochondral ossification.

Endochondral ossification (EO) occurs in the growth plate where chondrocytes pass through discrete stages of proliferation, maturation, hypertrophy, and calcification. We have developed and characterized a novel bovine cell culture model of EO that mirrors these events and will facilitate in vitro studies on factors controlling chondrocyte differentiation. Chondrocytes derived from the epiphyses of long bones of fetal calves were treated with 5-azacytidine (aza-C) for 48 h. Cultures were maintained subsequently without aza-C and harvested at selected time points for analyses of growth and differentiation status. A chondrocytic phenotype associated with an extensive extracellular matrix rich in proteoglycans and collagen types II and VI was observed in aza-C-treated and -untreated cultures. aza-C-treated cultures were characterized by studying the expression of several markers of chondrocyte differentiation. Parathyroid hormone-related protein (PTHrP) and its receptor, both markers of maturation, were expressed at days 5-9. Type X collagen, which is restricted to the stage of hypertrophy, was expressed from day 11 onward. Hypertrophy was confirmed by a 14-fold increase in cell size by day 15 and an increased synthesis of alkaline phosphatase during the hypertrophic period (days 14-28). The addition of PTHrP to aza-C-treated cultures at day 14 led to the down-regulation of type X collagen by 6-fold, showing type X collagen expression is under the control of PTHrP as in vivo. These findings show that aza-C can induce fetal bovine epiphyseal chondrocytes to differentiate in culture in a manner consistent with that which occurs during the EO process in vivo.

Partial characterization of type X collagen from bovine growth-plate cartilage. Evidence that type X collagen is processed in vivo.

Sequential extraction of bovine growth-plate cartilage with 4 M guanidinium chloride and pepsin was used to identify the intact and pepsinized forms respectively of type X collagen. This collagen occurs predominantly as the processed [alpha 1(X)]3 form in vivo, although the procollagen [pro alpha 1(X)]3 form can also be detected. The bovine pro alpha 1(X) and alpha 1(X) chains have Mr values identical to the corresponding chick species (Mr 59,000 and 49,000). However, the pepsinized alpha 1(X)p chains (Mr 47,000) are larger than those of the chick (Mr 45,000), and the bovine collagen type X is further distinguished by being disulphide-bonded within the triple-helical domain.

Characterization of two corneal epithelium-derived antigens associated with vasculitis.

PURPOSE: In a previous investigation into corneal autoimmunity, it was demonstrated that a putative autoantigen, a protein of 66 kDa, present in bovine corneal epithelium, binds circulating autoantibodies in approximately 60% of patients with Wegener's granulomatosis (WG). The aim of the present study was to characterize and identify the 66-kDa protein. METHODS: A purification protocol was established for the 66-kDa protein using standard chromatography techniques. During the purification procedure it became clear that the 66-kDa protein detected in patients' sera was in fact two proteins, both running at 66 kDa on sodium dodecyl sulfate-polyacrylamide gel electrophoresis, that eluted in different fractions on DE-52 chromatography columns. These two proteins have been labeled bovine corneal epithelial antigen-A and -B (BCEA-A and BCEA-B). Further investigations of antibody binding have demonstrated that patients' sera bind to either one or the other of these proteins with no cross-reactivity between them. Separated BCEA-A and BCEA-B protein extracts were immunoblotted with 27 WG patients' sera, 10 Churg-Strauss syndrome (CSS) patients' sera, 31 rheumatoid arthritis (RA) patients' sera, and 40 healthy control subjects' sera from the blood bank. RESULTS: Forty-six percent of WG patients' sera had antibodies to one of the 66-kDa antigens, whereas none of the healthy control subjects' sera had 66-kDa antibodies (P < 10(-5)). In the WG group, 31% were positive to BCEA-A (versus controls, P = 0.0023), and 15% were positive to BCEA-B. WG patients with peripheral ulcerative keratitis (PUK) had a significant association with anti-BCEA-A antibodies when compared with healthy control subjects (50%, P < 10(-6)). However, in the RA group with no eye disease there was an association with BCEA-A (25%, P = 0.011) but not in the RA group with PUK. The frequency of anti-BCEA-B antibodies was significantly increased in patients with CSS (60%, P < 10(-7)). CONCLUSIONS: In summary, it has been shown that vasculitis patients have antibodies to two 66-kDa corneal antigens and that autoantibodies to these antigens are mutually exclusive. It has also been shown that antibodies to BCEA-B are associated with CSS, whereas BCEA-A antibodies are associated with WG and RA.

Departure from ideality in saturation binding assays.

In this paper we show that the measurement of cyclic AMP by a protein saturation assay deviates from ideality due to the presence of two classes of binding sites. An equation was derived which completely describes saturation assays and the effects on these of varying each of the component parameters was measured. The relevance of these findings to other protein saturation assays is discussed.