Restauração de dentes posteriores endodonciados

A restauração de dentes endodonciados é um verdadeiro desafio perante as inúmeras possibilidades restauradoras que atualmente se apresentam. A decisão na escolha da melhor restauração para dentes posteriores endodonciados, com intuito de promover uma reabilitação estética e funcional, com menor prejuízo possível dos tecidos dentais e com maior longevidade é portanto, bastante complexa. Este estudo faz uma revisão de literatura para inter-relacionar o planeamento, a posição do dente na arcada e o tecido dentário remanescente com os diversos tipos de restauração (direta ou indireta). Avalia também a necessidade da colocação ou não de espigão e o seu tipo, assim como os tipos de cimentos utilizados durante o procedimento restaurador. Para tal foi efetuada uma pesquisa bibliográfica recorrendo aos motores de busca de MEDLINE, LILACS e PubMED, entre 2000 e 2015, com as seguintes palavras-chaves: “endodontically treated teeth”, “teeth restoration”, “tooth structure”, “post use”, “post materials”, “resin-based composite”, “ceramic”, “tooth fracture”, “cusp coverage”, “bicuspid”, “weakened teeth”, “cavity preparation design”. Concluiu-se que o sucesso de uma restauração em dentes posteriores endodonciados está na interpretação inicial do prognóstico antes mesmo do inicio do tratamento endodôntico e que quantidade e qualidade do tecido remanescente e o tipo de forças que incidirão no dente em questão, serão aspectos importantes na escolha do tipo de restauração e sua longevidade.

Efficacy and Safety of Orally Administered Intravenous Midazolam Versus a Commercially Prepared Syrup

Background: Among different categories of sedative agents, benzodiazepines have been prescribed for more than three decades to patients of all ages. The effective and predictable sedative and amnestic effects of benzodiazepines support their use in pediatric patients. Midazolam is one of the most extensively used benzodiazepines in this age group. Oral form of drug is the best accepted route of administration in children. Objectives: The purpose of this study was to compare the efficacy and safety of a commercially midazolam syrup versus orally administered IV midazolam in uncooperative dental patients. Second objective was to determine whether differences concerning sedation success can be explained by child‘s behavioral problems and dental fear. Patients and Methods: Eighty eight uncooperative dental patients (Frankl Scales 1,2) aged 3 to 6 years, and ASA I participated in this double blind, parallel randomized, controlled clinical trial. Midazolam was administered in a dose of 0.5 mg/kg for children under the age 5 and 0.2 mg/kg in patients over 5 years of age. Physiologic parameters including heart rate, respiratory rate, oxygen saturation and blood pressure were recorded. Behavior assessment was conducted throughout the course of treatment using Houpt Sedation Rating Scale and at critical moments of treatment (injection and cavity preparation) by North Carolina Scale. Dental fear and behavioral problems were evaluated using Child Fear Schedule Survey-Dental Subscale (CFSS-DS), and Strength and Difficulties Questionnaire (SDQ). Independent t-test, Chi-Square, and Pearson correlation were used for statistical analysis. Results: Acceptable overall sedation ratings were observed in 90% and 86% of syrup and IV/Oral group respectively; Chi-Square P = 0.5. Other domains of Houpt Scale including: sleep, crying and movement were also not significantly different between groups. Physiological parameters remained in normal limits during study without significant difference between groups. Conclusions: “Orally administered IV midazolam” preparation can be used as an alternative for commercially midazolam syrup.

A computerized tomography scan method for calculating the hernia sac and abdominal cavity volume in complex large incisional hernia with loss of domain

Preoperative progressive pneumoperitoneum (PPP) is a safe and effective procedure in the treatment of large incisional hernia (size > 10 cm in width or length) with loss of domain (LIHLD). There is no consensus in the literature on the amount of gas that must be insufflated in a PPP program or even how long it should be maintained. We describe a technique for calculating the hernia sac volume (HSV) and abdominal cavity volume (ACV) based on abdominal computerized tomography (ACT) scanning that eliminates the need for subjective criteria for inclusion in a PPP program and shows the amount of gas that must be insufflated into the abdominal cavity in the PPP program. Our technique is indicated for all patients with large or recurrent incisional hernias evaluated by a senior surgeon with suspected LIHLD. We reviewed our experience from 2001 to 2008 of 23 consecutive hernia surgical procedures of LIHLD undergoing preoperative evaluation with CT scanning and PPP. An ACT was required in all patients with suspected LIHLD in order to determine HSV and ACV. The PPP was performed only if the volume ratio HSV/ACV (VR = HSV/ACV) was a parts per thousand yen25% (VR a parts per thousand yen 25%). We have performed this procedure on 23 patients, with a mean age of 55.6 years (range 31-83). There were 16 women and 7 men with an average age of 55.6 years (range 31-83), and a mean BMI of 38.5 kg/m(2) (range 23-55.2). Almost all patients (21 of 23 patients-91.30%) were overweight; 43.5% (10 patients) were severely obese (obese class III). The mean calculated volumes for ACV and HSV were 9,410 ml (range 6,060-19,230 ml) and 4,500 ml (range 1,850-6,600 ml), respectively. The PPP is performed by permanent catheter placed in a minor surgical procedure. The total amount of CO(2) insufflated ranged from 2,000 to 7,000 ml (mean 4,000 ml). Patients required a mean of 10 PPP sessions (range 4-18) to achieve the desired volume of gas (that is the same volume that was calculated for the hernia sac). Since PPP sessions were performed once a day, 4-18 days were needed for preoperative preparation with PPP. The mean VR was 36% (ranged from 26 to 73%). We conclude that ACT provides objective data for volume calculation of both hernia sac and abdominal cavity and also for estimation of the volume of gas that should be insufflated into the abdominal cavity in PPP.

Effect of the C-factor and Dentin Preparation Method in the Bond Strength of a Mild Self-etch Adhesive

This study evaluated the effect of the C-factor and dentin preparation method (DPM) in the bond strength (BS) of a mild self-etch adhesive; the study also observed the SEM superficial aspects of the corresponding smear layer. For purposes of this study, 25 molars (n=5) were used in a bond strength test. The molars were divided into two parts (buccal and lingual): one part received a Class V cavity (C-factor=3) and the other received a flat surface (C-factor=0) with the same bur type (coarse diamond or carbide bur and fine diamond or carbide bur), both within the same dentin depth. Five teeth were prepared with wet 60-grit and 600-grit SiC papers. After restoration with Clearfil SE Bond, microtensile beans (0.8 mm(2)) were prepared and tested after 24 hours in a universal testing machine (0.5 mm/minute). An additional two teeth for each DPM were prepared for SEM evaluation of the smear layer superficial aspects. The BS values were submitted to one-way ANOVA, considering only the DPM (flat surfaces) and two-way ANOVA (C-Factor x DPM, considering only burs) with p=0.05. Although the DPM in the flat surfaces was not significant, the standard deviations of carbide bur-prepared specimens were markedly lower. The BS was significantly lower in cavities. The fine carbide bur presented the most favorable smear layer aspect. It was concluded that different dentin preparation methods could not prevent the adverse effect in bond strength of a high C-factor. A coarse cut carbide bur should be avoided prior to a mild self-etch adhesive, because it adversely affected bond strength. In contrast, a fine cut carbide bur provided the best combination: high bond strength with low variability, which suggests a more reliable bond strength performance.

Imaging pheromone sensing in a mouse vomeronasal acute tissue slice preparation.

Peter Karlson and Martin Lüscher used the term pheromone for the first time in 1959 to describe chemicals used for intra-species communication. Pheromones are volatile or non-volatile short-lived molecules secreted and/or contained in biological fluids, such as urine, a liquid known to be a main source of pheromones. Pheromonal communication is implicated in a variety of key animal modalities such as kin interactions, hierarchical organisations and sexual interactions and are consequently directly correlated with the survival of a given species. In mice, the ability to detect pheromones is principally mediated by the vomeronasal organ (VNO), a paired structure located at the base of the nasal cavity, and enclosed in a cartilaginous capsule. Each VNO has a tubular shape with a lumen allowing the contact with the external chemical world. The sensory neuroepithelium is principally composed of vomeronasal bipolar sensory neurons (VSNs). Each VSN extends a single dendrite to the lumen ending in a large dendritic knob bearing up to 100 microvilli implicated in chemical detection. Numerous subpopulations of VSNs are present. They are differentiated by the chemoreceptor they express and thus possibly by the ligand(s) they recognize. Two main vomeronasal receptor families, V1Rs and V2Rs, are composed respectively by 240 and 120 members and are expressed in separate layers of the neuroepithelium. Olfactory receptors (ORs) and formyl peptide receptors (FPRs) are also expressed in VSNs. Whether or not these neuronal subpopulations use the same downstream signalling pathway for sensing pheromones is unknown. Despite a major role played by a calcium-permeable channel (TRPC2) present in the microvilli of mature neurons TRPC2 independent transduction channels have been suggested. Due to the high number of neuronal subpopulations and the peculiar morphology of the organ, pharmacological and physiological investigations of the signalling elements present in the VNO are complex. Here, we present an acute tissue slice preparation of the mouse VNO for performing calcium imaging investigations. This physiological approach allows observations, in the natural environment of a living tissue, of general or individual subpopulations of VSNs previously loaded with Fura-2AM, a calcium dye. This method is also convenient for studying any GFP-tagged pheromone receptor and is adaptable for the use of other fluorescent calcium probes. As an example, we use here a VG mouse line, in which the translation of the pheromone V1rb2 receptor is linked to the expression of GFP by a polycistronic strategy.

Periapical tissue healing after post space preparation with or without use of a protection plug and root canal exposure to the oral environment. Study in dogs

The purpose of this study was to evaluate the influence of coronal leakage on the healing of dogs' periapical tissues after root canal filling, post space preparation and protection or not with a temporary sealer plug. Forty root canals of dogs' teeth were instrumented and filled by the lateral condensation technique with gutta-percha points and Endomethasone or CRCS sealers. After post space preparation, the remaining filling material was protected or not with a plug of temporary Coltosol sealer and exposed to the oral environment for 90 days. Thereafter, the animals were sacrificed and the specimens were removed and prepared for histomorphological and histobacteriological analysis. The findings revealed 35% of microbial leakage in the groups without plugs and 15% of leakage in the groups with plugs. Statistical analysis showed that the use of a Coltosol plug improved significantly the histomorphological results regardless of the type of root canal sealer (p=0.05) and that CRCS and Endomethasone sealers showed similar results (p>0.05).

Cone-beam computed tomography analysis of the apical third of curved roots after mechanical preparation with different automated systems

The present study evaluated by cone-beam computed tomography (CBCT) the apical canal transportation and centralizing ability of different automated systems after root canal preparation. The mesiobuccal canals of maxillary first molars (n=10 per group) were prepared with: GI - reciprocating system with K-Flexofile; GII - reciprocating system with NiTiFlex files; GIII - rotary system with K3 instruments; GIV - rotary system with RaCe instruments. CBCT scans were taken before and after biomechanical preparation up to a #40.02 diameter. Canal transportation was determined by measuring the smallest distance between the inner canal walls and the mesial and distal sides of the root. The centralization ability corresponded to the difference between the measurements from transportation evaluation, using the linear voxel to voxel method of analysis. The mean transportation was 0.06 ± 0.14 mm, with a tendency to deviate to the mesial side of the root (n=22), with no statistically significant difference among the groups (p=0.4153). The mean centralization index was 0.15 ± 0.65 also without statistically significant difference among the groups (p=0.0881). It may be concluded that apical canal transportation and centralization ability were not influenced by the type of mechanical movement and instruments used.

Micro-CT assessment of two different endodontic preparation systems

The aim of this study was to compare two endodontic preparation systems using micro-CT analysis. Twenty-four one-rooted mandibular premolars were selected and randomly assigned to two groups. The samples (n = 12) of Group 1 were prepared using the ProTaper Universal rotary system, while Group 2 (n = 12) was prepared using the EndoEZE AET system complemented by manual apical preparation with K-type hand files up to #30. A 2.5% sodium hypochlorite solution was used in both groups for irrigating. Both groups were scanned by highresolution microcomputed tomography before and after preparation (SkyScan 1172, SkyScan, Kontich, Belgium). The root canal volume and surface area was measured before and after preparation, and the differences were calculated and analyzed for statistically significant differences using ANOVA complemented by the Tukey test (p < 0.05). The results showed no statistically significant differences between the mean volumes of dentin removal by the two systems. However, the EndoEZE AET system presented a significantly greater mean surface area compared to the ProTaper system (p < 0.05). The EndoEZE AET system enabled preparation of a greater root canal surface area when compared to the ProTaper Universal system. There seemed to be no difference in dentin volume loss between the two systems used.

Analysis of kinematic, kinetic and electromyographic patterns during root canal preparation with rotary and manual instruments

Objective: This study assessed the muscular activity during root canal preparation through kinematics, kinetics, and electromyography (EMG). Material and Methods: The operators prepared one canal with RaCe rotary instruments and another with Flexofiles. The kinematics of the major joints was reconstructed using an optoelectronic system and electromyographic responses of the flexor carpi radial's, extensor carpi radialis, brachioradialis, biceps brachii, triceps brachii, middle deltoid, and upper trapezius were recorded. The joint torques of the shoulder, elbow and wrist were calculated using inverse dynamics. In the kinematic analysis, angular movements of the wrist and elbow were classified as low risk factors for work-related musculoskeletal disorders. With respect to the shoulder, the classification was medium-risk. Results: There was no significant difference revealed by the kinetic reports. The EMG results showed that for the middle deltoid and upper trapezius the rotary instrumentation elicited higher values. The flexor carpi radialis and extensor carpi radialis, as well as the brachioradialis showed a higher value with the manual method. Conclusion: The muscular recruitment for accomplishment of articular movements for root canal preparation with either the rotary or manual techniques is distinct. Nevertheless, the rotary instrument presented less difficulty in the generation of the joint torque in each articulation, thus, presenting a greater uniformity of joint torques.

Efficient 1535 nm light emission from an all-Si-based optical micro-cavity containing Er3+ and Yb3+ ions

This work reports on the construction and spectroscopic analyses of optical micro-cavities (OMCs) that efficiently emit at ~1535 nm. The emission wavelength matches the third transmission window of commercial optical fibers and the OMCs were entirely based on silicon. The sputtering deposition method was adopted in the preparation of the OMCs, which comprised two Bragg reflectors and one spacer layer made of either Er- or ErYb-doped amorphous silicon nitride. The luminescence signal extracted from the OMCs originated from the 4I13/2→4I15/2 transition (due to Er3+ ions) and its intensity showed to be highly dependent on the presence of Yb3+ ions.According to the results, the Er3+-related light emission was improved by a factor of 48 when combined with Yb3+ ions and inserted in the spacer layer of the OMC. The results also showed the effectiveness of the present experimental approach in producing Si-based light-emitting structures in which the main characteristics are: (a) compatibility with the actual microelectronics industry, (b) the deposition of optical quality layers with accurate composition control, and (c) no need of uncommon elements-compounds nor extensive thermal treatments. Along with the fundamental characteristics of the OMCs, this work also discusses the impact of the Er3+-Yb3+ ion interaction on the emission intensity as well as the potential of the present findings.

Preparation and optimization of calcium fluoride particles for dental applications.

Fluorides are used in dental care due to their beneficial effect in tooth enamel de-/remineralization cycles. To achieve a desired constant supply of soluble fluorides in the oral cavity, different approaches have been followed. Here we present results on the preparation of CaF2 particles and their characterization with respect to a potential application as enamel associated fluoride releasing reservoirs. CaF2 particles were synthesized by precipitation from soluble NaF and CaCl2 salt solutions of defined concentrations and their morphology analyzed by scanning electron microscopy. CaF2 particles with defined sizes and shapes could be synthesized by adjusting the concentrations of the precursor salt solutions. Such particles interacted with enamel surfaces when applied at fluoride concentrations correlating to typical dental care products. Fluoride release from the synthesized CaF2 particles was observed to be largely influenced by the concentration of phosphate in the solution. Physiological solutions with phosphate concentration similar to saliva (3.5 mM) reduced the fluoride release from pure CaF2 particles by a factor of 10-20 × as compared to phosphate free buffer solutions. Fluoride release was even lower in human saliva. The fluoride release could be increased by the addition of phosphate in substoichiometric amounts during CaF2 particle synthesis. The presented results demonstrate that the morphology and fluoride release characteristics of CaF2 particles can be tuned and provide evidence of the suitability of synthetic CaF2 particles as enamel associated fluoride reservoirs.

Micro-Fabricated Surface Trap and Cavity Integration for Trapped Ion Quantum Computing

Atomic ions trapped in micro-fabricated surface traps can be utilized as a physical platform with which to build a quantum computer. They possess many of the desirable qualities of such a device, including high fidelity state preparation and readout, universal logic gates, long coherence times, and can be readily entangled with each other through photonic interconnects. The use of optical cavities integrated with trapped ion qubits as a photonic interface presents the possibility for order of magnitude improvements in performance in several key areas of their use in quantum computation. The first part of this thesis describes the design and fabrication of a novel surface trap for integration with an optical cavity. The trap is custom made on a highly reflective mirror surface and includes the capability of moving the ion trap location along all three trap axes with nanometer scale precision. The second part of this thesis demonstrates the suitability of small micro-cavities formed from laser ablated fused silica substrates with radii of curvature in the 300-500 micron range for use with the mirror trap as part of an integrated ion trap cavity system. Quantum computing applications for such a system include dramatic improvements in the photonic entanglement rate up to 10 kHz, the qubit measurement time down to 1 microsecond, and the measurement error rates down to the 10e-5 range. The final part of this thesis details a performance simulator for exploring the physical resource requirements and performance demands to scale such a quantum computer to sizes capable of performing quantum algorithms beyond the limits of classical computation.

Preparation Of An Agar-silver Nanoparticles (a-agnp) Film For Increasing The Shelf-life Of Fruits.

Preparation of protective coating possessing antimicrobial properties is present day need as they increase the shelf life of fruits and vegetables. In the present study, preparation of agar-silver nanoparticle film for increasing the shelf life of fruits is reported. Silver nanoparticles (Ag-NPs) biosynthesised using an extract of Ocimum sanctum leaves, were mixed with agar-agar to prepare an agar-silver nanoparticles (A-AgNp) film. This film was surface-coated over the fruits, Citrus aurantifolium (Thornless lime) and Pyrus malus (Apple), and evaluated for the determination of antimicrobial activity of A-AgNp films using disc diffusion method, weight loss and shelf life of fruits. This study demonstrates that these A-AgNp films possess antimicrobial activity and also increase the shelf life of fruits.

Preparation, Characterization And In Vitro Digestibility Of Gellan And Chitosan-gellan Microgels.

Gellan microgels with potential application in delivery systems were obtained by physically cross-linked gellan gum. The microgels were produced by atomization followed by ionotropic gelation using CaCl2 (gellan/Ca) or KCl (gellan/K) as hardening agent and part of them were coated with chitosan in order to improve their resistance to gastric digestion. Size distribution, morphology and zeta potential of microgels were evaluated before and after in vitro digestion process. The long term stability was also evaluated. Spherical microparticles were obtained at gellan concentration above 0.6% w/w, showing average size among 70-120 μm. Most of the coated and uncoated microgels showed stability in aqueous media, except the uncoated gellan/K microgel. The in vitro digestion evaluation showed that all particles maintained their size and shape after the gastric digestion step. However, the enteric digestion caused disintegration of microgels indicating their potential application for enteric delivery systems. The chitosan-coated microgels showed lower degree of fragmentation when compared to the uncoated microgels, indicating that the coating process enable a better control of microgels releasing properties during the enteric digestion.

Diagnosis and treatment of extraction sockets in preparation for implant placement: report of three cases

This article addresses diagnostic parameters that should be assessed in the treatment of extraction sockets with dental implant placement by presenting three case reports that emphasize the relevance of the amount of remaining bone walls. Diagnosis was based on the analysis of clinical and radiographic parameters (e.g.: bone defect morphology, remaining bone volume, presence of infections on the receptor site). Case 1 presents a 5-wall defect in the maxillary right central incisor region with severe root resorption, which was treated with immediate implant placement. Cases 2 and 3 present, respectively, two- and three-wall bone defects that did not have indication for immediate implants. These cases were first submitted to a guided bone regeneration (GBR) procedure with bone graft biomaterial and membrane barriers, and the implants were installed in a second surgical procedure. The analysis of the preoperative periodontal condition of the adjacent teeth and bone defect morphology is extremely important because these factors determine the choice between immediate implant or GBR treatment followed by implant installation in a subsequent intervention.