Clinical performance of computer-aided design/computer-aided manufacture lithium disilicate ceramic endocrown restorations: A 2-year study

Context

Optimal restoration methods for endodontically treated teeth (ETTs) have always remained an ongoing discussion among physicians in this day and age. ETTs have a tendency to fracture when chewing, compared to initial teeth. From the perspective of biology, preserving and restoring tooth structure is critical to maintaining biomechanical, functional, and esthetic harmony. Dental bonding techniques have lessened the necessity for post-and-core restorations in ETTs with severe substance loss. A minimally invasive endodontic restoration technique called "endocrown" was initially introduced by Bindl and Mörmann in 1999.

Aims

The aim of the study was to clinically evaluate all-ceramic mandibular molar endocrowns made using computer-aided design/computer-aided manufacturing (CAD/CAM) following 2 years of follow-up.

Subjects and Methods

This unblinded study contains 56 patients with 56 mandibular molars, which had severe substance loss. After teeth preparation, lithium disilicate ceramic endocrowns were manufactured with the CEREC CAD/CAM system, and cementation was performed using a composite luting agent. The endocrowns were assessed using the modified United States Public Health Service criteria at baseline, 6 months, 1 year, and 2 years following placement. Patient satisfaction was evaluated using a questionnaire.

Statistical Analysis Used

This study used descriptive statistics, including mean, standard deviation, and 95% confidence intervals. Data were processed using STATA version 14.0 (StataCorp LLC, USA).

Results

Two endocrowns (3.6%) failed throughout the period of observation. The high clinical rating criteria (96.4%, count of 54) and the increased satisfaction percentage (94.6%, count of 53) remained practically stable during the follow-up assessments at 6 months and after 1-2 years.

Conclusions

Endocrown offers a less invasive treatment option that may be a better method for endodontically treated mandibular molars. With contemporary CAD/CAM technology and new materials, time in the chair and esthetics optimally improved, bringing satisfaction to the patient.

Effect of three different preparation designs on the marginal adaptation of indirect overlay restoration fabricated from lithium disilicate ceramic material: An in-vitro comparative study

Objectives

Marginal adaptation is considered one of the key factors influencing the success of indirect restorations. This study aimed to estimate the marginal fit of lithium disilicate overlays with three distinct preparation designs before and after cementation.

Methods

Thirty maxillary first premolars were divided into the hollow chamfer design (HCD) group, butt-joint design (BJD) group, and conventional occlusal box design (COD) group (n = 10 each). The samples were scanned using an intra-oral scanner, and overlays were fabricated using computer-assisted design and milled on a computer-assisted machine. The finished restorations were luted using a self-adhesive resin RelyX Ultimate. The marginal gap was assessed using a digital microscope with 230X magnification power. Statistical analysis was conducted using analysis of variance and post hoc (Bonferroni correction) tests, assuming a significance level of 5%.

Results

The HCD and BJD groups recorded significantly lower marginal gap, (11.39 ± 0.72, 16.29 ± 0.75) and (11.59 ± 0.75, 16.93 ± 0.65) respectively, than the COD group (24.57 ± 1.18, 34.45 ± 1.09) both pre- and post-cementation.

Conclusion

This study demonstrated that modification of tooth preparation plays a significant role in the marginal adaptation of the lithium disilicate overlays. The gap was smaller with the HCD and BJD than with the COD, with a statistically significant difference.