Polyethylene fiber tape used as a post and core in decayed primary anterior teeth: a treatment option.

The early loss of the anterior primary teeth can cause problems in phonation, development of the maxilla and is related to deleterious habits. This case presents the clinical sequence of rehabilitation of upper anterior primary teeth, where endodontic treatments were done. This was followed by the construction of root post using polyethylene ribbon fibers and the fabrication of crowns composed of resin.     

Partitioned polymerization, 4. Seeded emulsion polymerization of methyl methacrylate

The shape of the conversion curves and the rates of the emulsion polymerization in batch of methyl methacrylate (MMA) in the presence of seed particles of poly(butyl acrylate) (PBA) depend on the mass ratio of methyl methacrylate/poly(butyl acrylate) MMA/PBA and on the presence or absence of 2,2,6,6-tetramethyl-4-octadecanoyloxypiperidinyl-1-oxyl (STMPO). Irrespective of the presence and/or absence of STMPO in the reaction system, the diameter of a polumer particle experimentally found and calculated on the assumption that no new crop of polymer particles is formed, agrees well for systems with “low” (0,632) mass ratio of MMA/PBA. For systems with “high” (3,160) mass ratio of MMA/PBA, the calculated diameter is higher than that experimentally measured. This indicates that for “low” values of MMA/PBA, all poly(methyl methacrylate) formed was only used for building up shells of poly(butyl acrylate) particles. For “high” values of MMA/PBA, about 37 mass-% (in the absence of STMPO) or 57 mass-% (in the presence of STMPO) of poly(methyl methacrylate) formed was used for generating a crop of poly(methyl methacrylate) particles. Retardation of the polymerization rate in the presence of STMPO is more pronounced for systems characterized by a “low” value of the mass ratio MMA/PBA. Only short inhibition periods (up to five minutes) were observed for both “low” and “high” MMA/PBA ratios. It is shown that for the “low” mass ratio of MMA/PBA the “inner” monomer transport (from PBA particles swollen with MMA) to the locus of propagation is decisive. For systems with a “hugh” mass ratio MMA/PBA, the “outer” monomer transport from monomer droplets and micelles swollen by monomer to the locus of propagation is of primary importance. To explain the experimental results a reaction mechanism for the seeded emulsion polymerization is proposed.     

Optic density at 650 nm and phosphatidylglycerol in the evaluation of fetal pulmonary maturity]

The authors studied the correlation between optical density at 650 nm (OD650) and phosphatidylglycerol (PG) in 52 samples of amniotic fluid obtained by amniocentesis in which the shake test was negative 22 out of 52 samples (42.3%) had detectable amounts of PG (> or = 2%). Our results clearly demonstrate that OD650 is unable in predicting the presence of absence of PG in those immature samples of amniotic fluid according to the shake test.     

Left ventricular non-compaction and idiopathic dilated cardiomyopathy: the significant diagnostic value of longitudinal strain

Left ventricular non-compaction (LV NC) is characterized by abnormal trabeculations that are mainly at the LV apex. Distinction between LV NC and non-specific dilated cardiomyopathies (DCMs) remains often challenging. We sought to find additive tools comparing the longitudinal strain characteristics of LVNC versus idiopathic DCM in a cohort of patients. 48 cases of LVNC (derivation cohort) were compared with 45 cases of DCM. Global and regional multi-layer (sub-endocardial, mid-wall, and sub-epicardial) LV longitudinal strain analysis was performed. Results were compared to define the best tool for distinguishing LVNC from DCM. A validation cohort (41 LVNC patients) was then used to assess the performance of the proposed diagnostic tools. In the derivation cohort, longitudinal deformation (strain) was greater in LVNC than in DCM patients. Longitudinal shortening was greater in the non-compacted segments than in the compacted ones. A mid-wall strain base-apex gradient had 88.4?% sensitivity and 66.7?% specificity in distinguishing LVNC from DCM (AUC?=?0.83; cut-off of ?23 or |0.23|%). In a multivariable model, the base-apex mid-wall gradient in an apical 4-chamber view was the only independent echocardiographic criteria (OR?=?0.76, CI 95?% [0.66; 0.90], p?=?0.0010) allowing the distinction between LVNC and DCM. In the validation cohort, the base-apex mid-wall gradient of strain had 88.4?% sensitivity, 85.7?% negative predictive values for the diagnosis of LVNC. Longitudinal strain, especially the base-apex longitudinal gradient of strain, appears as an additive valuable tool for distinguishing LVNC from DCM.     

The effect of adjusting the pH of local anaesthetics in dentistry: a systematic review and meta‐analysis

The acidic nature of commercial local anaesthetics (LAs) can cause pain during infiltration and delay the onset of anaesthesia. It is suggested that adjusting the pH of anaesthetic agents could minimize these effects. This systematic review aimed to evaluate the efficacy of buffered LAs in reducing infiltration pain and onset time during dental procedures. MEDLINE, Embase, Scopus and Scielo databases were searched up to April 2017. Randomized controlled trials comparing buffered and unbuffered LAs for intraoral injections were included. Risk of bias was assessed using the Cochrane Collaboration tool. Data upon injection pain and onset time were pooled in a random‐effects model. Subgroup analyses compared normal and inflamed tissues, and terminal infiltrations and inferior alveolar nerve (IAN) blocks. Meta‐regressions were performed to explain heterogeneity. Fourteen articles were included in this review. Lidocaine with epinephrine was the most used anaesthetic combination. Nonlidocaine studies (n = 2) were not pooled in the meta‐analysis. Buffered lidocaine did not result in less pain during intraoral injections: mean difference ?6.4 (95% CI ?12.81 to 0.01) units in a 0–100 scale. Alkalinized lidocaine did not reduce the onset time in normal tissues when terminal infiltration techniques were used, but resulted in a more rapid onset for IAN blocks (?1.26 min) and in inflamed tissues (?1.37 min); however, this change may not be clinically relevant, considering the time required to prepare the buffered agent. Studies performed using other anaesthetic salts did not show robust and clinically significant results in favour of alkalinization.