One-year Clinical Results of Restorations Using a Novel Self-adhesive Composite Hybrid

This prospective study assessed the dual-curing self-adhesive composite hybrid Surefil one. The restorations were placed and reviewed by dental practitioners who are members of a practice-based research network in the United States. Seven practitioners filled 60 cavities (20 class I, 19 class II and 21 class V) in 41 patients with Surefil one without adhesive, according to the manufacturer’s instructions. The restorations were evaluated using modified rating criteria at baseline and after 3 months and 1 year. Patients were also contacted to report postoperative hypersensitivity 1 to 4 weeks after placement. Recall rates were 98% after 3 months and 82% after 1 year. The only patient that showed moderate hypersensitvity after 1 year had previously reported symptoms that were unlikely associated to the class I molar restoration. One class II restoration in a broken maxillary molar was partially lost. The remaining 48 restorations were found to be in clinically acceptable condition resulting in an annual failure rate of 2%. The lowest number of acceptable scores (88%) was for color match. Self-adhesive composite hybrid restorations showed promising results in stress-bearing class I and II as well as non-retentive class V cavities at 1-year recall.

Degree of Conversion and Mechanical Properties of Modern Self-Adhesive Luting Agents

New self-adhesive resin composite luting agents have currently been developed, claiming improved properties. The study aimed to evaluate the composition, degree of conversion, and mechanical properties of Panavia SA Plus (PSP), Panavia SA Universal (PSU), SpeedCem Plus (SPC) and TheraCem Ca (THC), with the resin luting agent Panavia V5 (PV5) serving as a control. The structure of the materials was studied by FTIR spectroscopy and SEM/EDX spectrometry. Disk-shaped specimens were prepared from each material under dual- and self-curing modes (n = 5/mode and material). After a 3-week storage period (dark/37 °C/80%RH) the Martens hardness, indentation modulus, elastic index, and creep were determined by instrumented indentation testing (IIT), while the degree of conversion was assessed by FTIR spectroscopy. Statistical analysis was performed by 2-way ANOVA and post-hoc testing (α = 0.05). All materials were based on aromatic monomers, except for SPC. Fillers with potentially bioactive Ca-glasses were identified in SPC and THC, which showed the highest P/Si ratio. The dual-curing mode demonstrated superior performance in all properties. Differences between materials within each curing mode were limited to SPC, THC (highest conversion) and PSA, PSU, SPC (highest elastic index) for dual-curing, and THC (lowest hardness and elastic index). The results confirmed a lower self-curing conversion in these materials, which may affect some of the mechanical properties tested.

Composites Manufactured by Stereolithography

Stereolithography (SLA) is a widely utilized rapid additive manufacturing process for prototypes and proof-of-concept models with high resolution. In order to create structurally sound components using SLA, reinforcement needs to be incorporated in the UV-based resins typically used. However, the introduction of reinforcement into vat-based SLA printers has had limited success due to a host of processing challenges including the creation of a homogeneous resin mixture and UV-inhibiting constituents. The effectiveness of using a dual curing system, consisting of a photo and thermal initiator, for the additive manufacturing of carbon fiber short-fiber composites via vat photopolymerization, was investigated. The necessary processing parameters were developed that resulted in successful printing and curing of composites at a 5% fiber volume. Manufacturing with reinforcements that have different densities from the resin creates separation issues, either suspending to the top or settling to the bottom. Following the approaches discussed in this chapter, an even distribution of short fibers was achieved throughout SLA printed samples using a modified commercial printer. Separation was overcome by inducing a continuous flow of reinforced liquid resin in the printer vat during printing. This flow field adaptation allows commercial SLA printers the ability to produce composite parts with different densities of the constituents utilized.