Composite Resin Preheating Techniques for Cementation of Indirect Restorations.

Purpose: Resin-based materials have been preheated by using different techniques and commercial devices. However, a consensus on the clinical protocol for cementing with preheated composite resins is lacking. The aim of this scoping review was to identify the different methods used for heating composite resins as used for cementing indirect adhesive restorations and to determine the benefits and limitations. Study Selection. A search was performed on PubMed/MEDLINE, Embase, Cochrane, Web of Science, Scopus, LIVIVO, and the nonpeer-reviewed literature database. Studies on preheating composite resins for cementing indirect restorations were included, with no restrictions on the type of study, year of publication, or language. The following data were extracted: preheating technique, the device used for preheating, preset temperature, and warming time. Results: In total, 304 studies were identified. After removing duplicates, 270 articles were selected, and 14 articles were included in the final evaluation. Half of the included studies reported similar preheating techniques using the Calset device for composite resins. The temperatures of 54°C and 68°C were most frequently reported, with a mean warming time of 5 minutes. Conclusions: Preheating composite resins for the cementation of indirect restorations reduces viscosity, but the material must be used promptly after removal from the device. Practical Implications. Different methodologies for preheating composite resins have been reported and used in clinical dental practice. To achieve good results and guide the clinician on use, the techniques for heating composite resins for cementation need to be standardized. Keeping the material warm until the restorative procedure, the thickness of the indirect restoration, and the composition of the composite resins can directly affect the outcome of the procedure.

Effect of maxillary median diastema on the esthetics of a smile.

INTRODUCTION: With the increasing demand for facial esthetics, patients' expectations regarding dental treatment have increased. The treatment of maxillary median diastemas (MMDs) stands out as one of the most noticeable esthetic alterations performed on patients. The objectives of the present article were to evaluate the effects of MMD and its restorations on the esthetics of a smile and to determine the differences in esthetic perceptions among 3 different groups of patients: orthodontists, prosthodontists, and laypeople. METHODS: Printed photographic images were randomly arranged in an album that contained the original photograph of the smile, 8 photographs with digitally created diastemas (0.5 mm, 1.0 mm, 1.5 mm, 2.0 mm, 2.5 mm, 3.0 mm, 4.0 mm, and 5.0 mm), and 8 with simulated restorations of these spaces. Each evaluator assigned scores to the images using a 100-mm visual analogue scale. RESULTS: Orthodontists, prosthodontists, and laypeople presented similar perceptions regarding the levels of attractiveness of the original smiles and those of smiles involving restorations of diastemas with widths of 0.5 mm and 1.0 mm. The ratings assigned to the smiles with diastemas differed significantly from those of the corresponding restored smile with the same magnitude of diastema. CONCLUSIONS: The prosthetic space closure of diastemas is better than leaving the space untreated. Restorations of MMD up to 1 mm perform similar to orthodontic closure. Larger MMDs are ideally treated with orthodontics because the restorative treatment is more invasive, leading to incremental damage to the dental tissues.

Influence of 2% chlorhexidine digluconate on bond strength of a glass-fibre post luted with resin or glass-ionomer based cement.

OBJECTIVES: This study evaluated the influence of 2% chlorhexidine digluconate (CHX) on the bond strength (BS) of a glass-fibre post to the root canal, regarding the cements (dual-cured resin or resin-modified glass-ionomer cement), the root thirds and the time of storage. METHOD: Eighty bovine roots were selected and endodontically treated, before being randomly assigned to the following groups according to the luting protocol: ARC (RelyX ARC); ARC+CHX; RL (RelyX Luting 2); and RL+CHX. After 24 h of luting, the roots were sliced to obtain 1 mm-thick slices. Half of each group was submitted to either 7-day or 6-month storage in artificial saliva (n=10). The specimens were subjected to push-out tests with a crosshead speed of 0.5 mm/min. The data were analysed with four-way ANOVA and Tukey's test (P≤0.05). The failure modes were analysed with a digital microscope (50× and 200×). RESULTS: ARC yielded a significantly higher BS compared to RL (P<0.001). Despite CHX exerted a significant effect; it depends on the interaction with the luting cement and time (P<0.001). Thus, CHX decreased the values of BS to those of ARC after 6 months (P<0.001). On the 7th day of storage, the ARC+CHX presented higher BS to the cervical and middle thirds compared to RL+CHX (P=0.012). Time solely was not a significant factor (P=0.081). Adhesive cement-dentine type and mixed failures were predominant modes for the ARC groups. For the RL groups, the main failures were adhesive cement-post and mixed modes. CONCLUSIONS: Glass-fibre posts luted with RelyX ARC dual-cure resin cement exhibited higher BS than those luted with RelyX Luting 2 resin-modified glass-ionomer cement. Furthermore, CHX was not effective to improve the BS and negatively affected the BS of RelyX ARC after 6 months of storage. CLINICAL SIGNIFICANCE: The use of chlorhexidine solution seems not to improve the bond strength of fibre posts to root canals, disregarding the composition of the luting cement.