Marginal discoloration of all-ceramic restorations cemented adhesively versus nonadhesively

Comparison of clinical efficacy of CAD CAM Endocrowns made of feldspathic ceramic, zirconia lithium silicate, and lithium disilicate: A two-year mixed cohort study

OBJECTIVE

Endocrowns can be fabricated from various materials as a treatment option for endodontically treated teeth. This mixed cohort study aimed to demonstrate the clinical efficacy of Endocrowns made of feldspathic, zirconia lithium silicate, and lithium disilicate ceramics using a chairside CAD/CAM system.

METHODS

The present study compared the clinical outcomes of 141 Endocrown restorations in posterior teeth of 85 patients in a two-year follow-up. The efficacy of restorations was evaluated in three aspects: esthetics, biological response, and function, with the aid of the FDI guideline, and presented as descriptive analyses. Additionally, the data were analyzed using Chi-square and Spearman correlation tests. The significance level was set at p = 0.05.

RESULTS

The study findings revealed that the type of restorations (feldspathic ceramic, zirconia lithium silicate, and lithium disilicate) (p > 0.05) and underlying teeth (molars and premolars) (p > 0.05) play no part in restorations' failure. Caries' recurrence is primarily responsible for the failure of the endocrowns. Secondary caries and radiolucency were observed in four teeth (2.83 %). The clinical efficacy of 126 restorations (89.36 %) fell into the category of "clinically excellent" and "clinically good." Ten restorations (7.09 %) were classified as "clinically sufficient/satisfactory," and only five restorations (3.54 %) needed replacement due to having "clinically unsatisfactory" and "clinically poor" quality.

CONCLUSIONS

Endocrowns showed a high success rate and durability in the short term, therefore can be considered a safe choice for restoring endodontically treated teeth. It is worth noting that caries were the most common reason for the failure of the restorations.

CLINICAL SIGNIFICANCE

Endocrowns made of different ceramics have been proven reliable restorations for endodontically treated molars and premolars.

Long-term clinical performance and complications of zirconia-based tooth- and implant-supported fixed prosthodontic restorations: A summary of systematic reviews

OBJECTIVES

To present an overview on systematic reviews on prosthodontic zirconia restorations and to discuss long-term complications as well as information on anatomical and functional changes to the masticatory system.

DATA/SOURCES

MEDLINE, EMBASE, Trip medical, and Cochrane Library databases were searched for systematic reviews up to February 2021. Bias was assessed and clinical survival and complications were analyzed.

STUDY SELECTION

38 eligible articles published between 2006 and 2021 were included. The reviews were based on 128 in vivo studies on approximately 10,000 zirconia restorations. 5-year cumulative survival rates varied between 91.2% and 95.9% for tooth-supported (TS) single crowns (SC), 89.4% and 100% for TS multi-unit fixed dental prostheses (FDP), 97.1% and 97.6% for implant-supported (IS) SCs and 93.0% and 100% for IS FDPs. Chipping was the most often technical complication, followed by framework fracture, loss of retention, marginal discrepancies/discoloration, occlusal roughness and abutment/screw loosening. Color mismatch was the only esthetic complication. Biological complications were caries, endodontic complications, tooth fracture, periodontal disease, abrasion/attrition, persisting pain, high sensitivity, peri‑implantitis and soft tissue issues. Patients with bruxism were only examined sporadically.

CONCLUSIONS

5-year results for zirconia restorations were satisfactory. The predominant technical problem of veneering fractures could be overcome with adapted design or fabrication and application of monolithic restorations, but reviews of clinical studies on this subject are rare. The impact of zirconia restorations on the masticatory system remains unclear.

CLINICAL SIGNIFICANCE

Zirconia restorations are experiencing a rapidly increasing use in dental practice. Being highly wear-resistant, hard and durable, it can be assumed that they do not follow natural abrasion and changes in the masticatory system. Possible long-term effects on the stomatognathic system as a whole should therefore be considered.

Viscosity and thermal kinetics of 10 preheated restorative resin composites and effect of ultrasound energy on film thickness

OBJECTIVE

This study investigated viscosity and thermal kinetics of 10 selected preheated restorative resin composites and the effect of ultrasound energy on film thickness.

METHODS

A range of different resin composites was tested: Charisma Diamond, IPS Empress Direct, Enamel Plus HRi, Essentia, Estelite Omega, Filtek Z100, Filtek Z350 XT, Gradia, TPH Spectrum and VisCalor. A flowable resin composite (Opallis Flow) and two resin cements (RelyX Veneer, Variolink Esthetic LC) also were tested. Viscosity (Pa s) was measured at 37 °C and 69 °C (preheating temperature) using a rheometer. Film thickness (μm) was measured before and after application of ultrasound energy. Temperature loss within resin composite following preheating (°C/s) was monitored. Data were statistically analyzed (α = 0.05).

RESULTS

Viscosity at 69 °C was lower than at 37 °C for all materials except the flowable resin composite. Preheating reduced viscosity between 47% and 92% for the restorative resin composites, which were generally more viscous than the flowable materials. Film thickness varied largely among materials. All preheated resin composites had films thicker than 50 μm without ultrasound energy. Application of ultrasound reduced film thickness between 21% and 49%. Linear and nonlinear regressions did not identify any relationship between filler loading, viscosity, and/or film thickness. All materials showed quick temperature reduction following preheating, showing maximum temperature loss rates after approximately 10 s.

SIGNIFICANCE

Distinct restorative resin composites react differently to preheating, affecting viscosity and film thickness. The overall performance of the preheating technique depends on proper material selection and use of ultrasound energy for reducing film thickness.