Esthetic Rehabilitation of Retained Primary Teeth-A Conservative Approach.

With the advancement in ceramic restorations bonded to tooth structure, the treatment has become a feasible and conservative option to restore teeth with alteration in shape when owing to high demand in esthetics, with or without minimum tooth preparation. This article describes a report of a 32-year-old woman who was dissatisfied with her smile. The patient reported that she still had deciduous teeth, and that the maxillary lateral incisors had been restored with direct resin composite to correct the teeth shape. After discussing the restorative possibilities, a decision was made to place all-ceramic crowns (lithium disilicate glass-ceramic) with minimal tooth preparation, which figures as a conservative full-coverage approach. An esthetic outcome resembling a natural-looking smile resulted in the patient's satisfaction. Bonding of all-ceramic crowns onto minimally prepared deciduous teeth figures as a conservative treatment in case of partial anodontia, which decreases the chance of root resorption induced by trauma and benefits from good adhesion to enamel.

Randomized clinical trial of 2 nonvital tooth bleaching techniques: A 1-year follow-up.

STATEMENT OF PROBLEM: Controlled clinical trials comparing the effectiveness of the walking bleaching (WB) technique and the inside-outside (I-O) technique used in a short daily regimen are lacking. PURPOSE: The purpose of this randomized clinical trial was to investigate the effectiveness of WB with that of the I-O technique conducted over 4 weeks and to compare color changes after 1 year. MATERIAL AND METHODS: Discolored and endodontically treated anterior teeth received a cervical seal and were randomly divided into groups according to the technique. In the WB group (n=9), a mixture of sodium perborate and 20% hydrogen peroxide was applied in the pulp chambers and replaced weekly up to 4 weeks. For the I-O group (n=8), participants applied 10% carbamide peroxide in the pulp chambers and wore custom-fitted trays for 1 hour per day over 4 weeks. CIELab parameters were obtained using a spectrophotometer at baseline, during bleaching (1, 2, 3, and 4 weeks) and after 1 year. Changes in color (ΔE), lightness (ΔL*), green-red axis (Δa*), blue-yellow axis (Δb*), and absolute color parameters (L*, b*, and a*) for each evaluation time were calculated and analyzed by repeated measures analysis of variance (ANOVA) and post hoc Bonferroni test (α=.05). RESULTS: No significant differences between WB and I-O techniques were observed for ΔE, ΔL*, Δa*, Δb*, L*, a*, or b* values (P>.05); however, significant differences were observed among the evaluation times (P<.05). Color changes observed after 2 weeks were stable after 1 year; ΔL* and Δa* values after 1 year were not significantly different from the 1-week evaluation, and significant changes in Δb* after 3 weeks were maintained at the 1-year follow-up. The same trend was observed for the absolute CIELab color parameters. CONCLUSIONS: Both WB and I-O regimens were similarly effective as shown by significant ΔE after 2 weeks and no color regression after 1 year.

Biomechanical behavior of endodontically treated premolars using different preparation designs and CAD/CAM materials.

OBJECTIVES: To evaluate the effect of restoration design ('2.5-mm deep endocrown', '5-mm deep endocrown' or '5-mm deep post&crown') and CAD/CAM material type (composite or lithium disilicate glass-ceramic) on the load-to-failure of endodontically treated premolars in absence of any ferrule. METHODS: The crowns of 48 single-rooted premolars were cut and the roots were endodontically treated. Teeth were randomly divided into six groups (n=8); teeth in each group were restored using one of the two tested materials with standardized CAD/CAM fabricated endocrowns (with either 2.5-mm or 5-mm deep intra-radicular extension) or conventional crowns (5-mm deep post&crown). After cementation using luting composite, the specimens were immersed in distilled water and subjected to 1,200,000 chewing cycles with a load of 50N applied parallel to the long axis of the tooth (0°). After cyclic loading, a compressive load was applied at 45° to the tooth's long axis using a universal testing machine until failure. Load-to-failure was recorded (N) and the specimens were examined under a stereomicroscope with 3.5x magnification to determine the mode of failure. RESULTS: All specimens survived the 1,200,000 chewing cycles. A significant interaction between restoration design and CAD/CAM material was found using two-way ANOVA. In the '2.5-mm deep endocrown' groups, the composite achieved a significantly higher load-to-failure than the lithium disilicate glass-ceramic, while no differences between materials were found in the '5-mm deep endocrown' and '5-mm deep post&crown' groups. More unfavorable failures (root fractures) were observed for higher load-to-failure values. CONCLUSIONS: Only following a '2.5-mm deep endocrown' design, composite appeared more favorable than lithium disilicate glass-ceramic as crown material; this may be explained by their difference in elastic modulus. CLINICAL SIGNIFICANCE: Shallow endocrown preparations on premolars present less surface for adhesive luting and a difference in crown material becomes apparent in terms of load-to-failure. The use of a more flexible composite crown material appeared then a better option.