Clinicians often face dilemmas regarding the most appropriate way to restore a tooth following root canal treatment. Whilst there is established consensus on the importance of the ferrule effect on ...the predictable restoration of root filled teeth, other factors, such as residual tooth volume, tooth location, number of proximal contacts, timing of the definitive restoration and the presence of cracks, have been reported to influence restoration and tooth survival. The continued evolution of dental materials and techniques, combined with a trend towards more conservative endodontic‐restorative procedures, prompts re‐evaluation of the scientific literature. The aim of this literature review was to provide an updated overview of the existing clinical literature relating to the restoration of root filled teeth. An electronic literature search of the PubMed, Ovid (via EMBASE) and MEDLINE (via EMBASE) databases up to July 2020 was performed to identify articles that related the survival of root filled teeth and/or restoration type. The following and other terms were searched: restoration, crown, onlay, root canal, root filled, post, clinical, survival, success. Wherever possible, only clinical studies were selected for the literature review. Full texts of the identified articles were independently screened by two reviewers according to pre‐defined criteria. This review identifies the main clinical factors influencing the survival of teeth and restorations following root canal treatment in vivo and discusses the data related to specific restoration type on clinical survival.
Effective management of external cervical resorption (ECR) depends on accurate assessment of the true nature and accessibility of ECR; this has been discussed in part 1 of this 2 part article. This ...aim of this article was firstly, to review the literature in relation to the management of ECR and secondly, based on the available evidence, describe different strategies for the management of ECR. In cases where ECR is supracrestal, superficial and with limited circumferential spread, a surgical repair without root canal treatment is the preferred approach. With more extensive ECR lesions, vital pulp therapy or root canal treatment may also be indicated. Internal repair is indicated where there is limited resorptive damage to the external aspect of the tooth and/or where an external (surgical) approach is not possible due to the inaccessible nature of subcrestal ECR. In these cases, root canal treatment will also need to be carried out. Intentional reimplantation is indicated in cases where a surgical or internal approach is not practical. An atraumatic extraction technique and short extraoral period followed by 2‐week splinting are important prognostic factors. Periodic reviews may be indicated in cases where active management is not pragmatic. Finally, extraction of the affected tooth may be the only option in untreatable cases where there are aesthetic, functional and/or symptomatic issues.
Total ionizing dose (TID) effects at the 7-nm bulk FinFET node are characterized under dynamic and static test conditions through changes in ring oscillator (RO) frequencies, leakage currents, and ...inverter delays. Results from total-dose exposures using the ARACOR X-ray machine showed that static conditions represented the worst case conditions. Higher operating frequencies resulted in increased leakage currents and inverter delays after irradiation. The rate of change for leakage current was inversely proportional to frequency during exposure. The rate of change for inverter delay was directly related to frequency during TID exposure. Overall, degradations in circuit-level parameters (logic gate delays and operating current) were less than 1% for TID exposures of 435 krad(SiO 2 ).
It has been predicted that upsets due to Single-Event Transients (SETs) in logic circuits will increase significantly with higher operating frequency and technology scaling. For synchronous circuits ...manufactured at advanced technology nodes, errors due to single-event transients are expected to exceed those due to latch upsets. Experimental results presented in this paper quantify the contribution of logic errors to the total Soft-Error Rate (SER) for test circuits fabricated in a 40 nm bulk CMOS technology. These results can be used to develop guidelines to assist circuit designers adopt effective hardening strategies to reduce the SER, while meeting performance specifications for high speed logic circuits.
Neutron- and proton-induced single-event upset cross sections of D- and DICE-Flip/Flops are analyzed for designs implemented in a 40 nm bulk technology node. Neutron and proton testing of the ...flip/flops show only a 30%-50% difference between D- and DICE-Flip/Flop error rates and cross sections. Simulations are used to show that charge sharing is the primary cause for the similar failures-in-time (FIT) rates. Such small improvement in the single-event performance of the DICE implementation over standard D-Flip/Flop designs may warrant careful consideration for the use of DICE designs in 40 nm bulk technologies and beyond.
Soft error rates for triple-well and dual-well SRAM circuits over the past few technology generations have shown an apparently inconsistent behavior. This work compares the heavy-ion induced upset ...cross-section in 28, 40, and 65 nm dual- and triple-well SRAMs over a wide range of particle LETs. Similar experiments on identical layouts for all these technologies along with 3-D TCAD simulations are used to identify the dominant mechanisms for single-event upsets. Results demonstrate that the well-engineering strongly influence the single-event response of SRAMs. Layout also plays an important role and the combined effects of well-engineering and layout determine the soft-error sensitivity of SRAMs fabricated in advanced technology nodes.
Power consumption for integrated circuits (ICs) fabricated at advanced technology nodes is a primary concern for application-specific IC (ASIC) designers. To reduce power consumption, designers use ...transistors with different threshold voltage (Formula Omitted) options and may reduce the supply voltage, oftentimes to as low as transistor-threshold-voltage levels. This work investigates the effects of these two popular techniques, different Formula Omitted options, and near-threshold-voltage (NTV) operation on the single-event (SE) performance of conventional D flip-flop (D-FF) cells in low-power applications. Results indicate that at near NTV levels, the SE cross section increases by two orders of magnitude, and the low Formula Omitted (LVT) option yields the best SE performance in comparison to the standard Formula Omitted (SVT) and ultralow Formula Omitted (uLVT) options.
Charge sharing between adjacent devices can lead to increased Single Event Upset (SEU) vulnerability. Key parameters affecting charge sharing are examined, and relative collected charge at the hit ...node and adjacent nodes are quantified. Results show that for a twin-well CMOS process, PMOS charge sharing can be effectively mitigated with the use of contacted guard-ring, whereas a combination of contacted guard-ring, nodal separation, and interdigitation is required to mitigate the NMOS charge sharing effect for the technology studied
Heavy-ion broad-beam experiments on a 130 nm CMOS technology have shown anomalously-short single-event transient pulse widths. 3-D TCAD mixed-mode modeling in 90 nm and 130 nm bulk CMOS has ...identified a mechanism for simultaneous charge collection on proximal circuit nodes interacting in a way as to truncate, or ¿quench,¿ a propagated voltage transient, effectively limiting the observed SET pulse widths at high LET. This quenching mechanism is described and analyzed.
Heavy-ion experimental results from flip-flops in 180-nm to 28-nm bulk technologies are used to quantify single-event upset trends. The results show that as technologies scale, D flip-flop ...single-event upset cross sections decrease while redundant storage node flip-flops cross sections may stay the same or increase depending on the layout spacing of storage nodes. As technology feature sizes become smaller, D flip-flop single-event upset cross sections approach redundant storage node hardened flip-flops cross sections for particles with high linear energy transfer values. Experimental results show that redundant storage node designs provide > 100{\rm X} improvement in single-event upset cross section over DFF for ion linear energy transfer values below 10~\hbox{MeV-cm}^2/\hbox{mg} down to 28-nm feature sizes.
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