Microleakage around zirconia crown margins after ultrasonic scaling with self-adhesive resin or resin modified glass ionomer cement

Evaluation of Microleakage Using Different Luting Cements in Kedo Zirconia Crowns: An In Vitro Assessment

Introduction A space between the prepared tooth and the cemented crown can cause microleakage, allowing microorganisms to enter, which in turn leads to the breakdown of the luting cement. To achieve an optimum fit, several factors should be considered, including the type of crown used, the taper of tooth preparation, and the type of cementing agent. Aim The purpose of the current study is to evaluate the microleakage of zirconia crowns cemented with glass ionomer cement (GIC), resin-modified GIC (RMGIC), and self-adhesive resin cement. Materials Forty-five primary mandibular molars were divided into three groups: Group I receiving GIC, Group II receiving RMGIC, and Group III receiving self-adhesive resin cement. These cements were used to lute the teeth with Kedo zirconia crowns. The restored samples underwent thermal cycling and were assessed for microleakage under a stereomicroscope. For the statistical analysis, SPSS version 23.0 was used. Descriptive statistics were presented as frequencies and percentages. Analytical statistics, including the Mann Whitney U test, were used to assess the differences in the level of microleakage between the groups at p < 0.05. Results The Mann Whitney U test revealed no significant difference in the level of microleakage between GIC and RMGIC (p = 0.072). However, self-adhesive resin cement showed significantly less microleakage than GIC (p = 0.000). Similarly, when comparing RMGIC and self-adhesive resin cement, the latter showed significantly less microleakage than the former (p = 0.001). Conclusion Microleakage of Kedo zirconia crowns on mandibular first molars was highest when luted with GIC, followed by RMGIC, and was least when luted with self-adhesive resin cement.

An evaluation of quantitative percussion diagnostics for determining the probability of a microgap defect in restored and unrestored teeth: A prospective clinical study

STATEMENT OF PROBLEM

Current dental diagnostics are image based and cannot detect a structural microgap defect such as a crack in a tooth. Whether percussion diagnostics can effectively diagnose a microgap defect is unclear.

PURPOSE

The purpose of the present study was to determine from a large multicenter prospective clinical study whether quantitative percussion diagnostics (QPD) could detect structural damage in teeth and whether a probability of its presence could be provided.

MATERIAL AND METHODS

A nonrandomized prospective and multicenter clinical validation study with 224 participants was performed in 5 centers with 6 independent investigators. The study used QPD and the normal fit error to determine whether a microgap defect was present in a natural tooth. Teams 1 and 2 were blinded. Team 1 tested teeth scheduled for restoration with QPD, and Team 2 disassembled the teeth aided by a clinical microscope, transillumination, and a penetrant dye. Microgap defects were documented in written and video formats. Controls were participants without damaged teeth. The percussion response from each tooth was stored on a computer and analyzed. A total of 243 teeth were tested to provide approximately 95% power to test the performance goal of 70%, based on an assumed population overall agreement of 80%.

RESULTS

Regardless of the collection method, tooth geometry, restoration material used, or restoration type, the data on detecting a microgap defect in a tooth were accurate. The data also reflected good sensitivity and specificity consistent with previously published clinical studies. The combined study data showed an overall agreement of 87.5% with a 95% confidence interval (84.2 to 90.3), beyond the 70% predetermined performance goal. The combined study data determined whether it was possible to predict the probability of a microgap defect.

CONCLUSIONS

The results showed that the data on detecting microgap defects in a tooth site were consistently accurate and confirmed that QPD provided information to aid the clinician in treatment planning and early preventative treatment. QPD can also alert the clinician of probable diagnosed and undiagnosed structural problems via the use of a probability curve.

Comparison of the clinical outcomes of resin-modified glass ionomer and self-adhesive resin cementations for full-coverage zirconia restorations

OBJECTIVES

Both resin-modified glass ionomer cement (RMGIC) and self-adhesive resin cement (SAC) may be suitable for cementation of full-coverage zirconia restorations. This retrospective study aimed to investigate the clinical outcomes of zirconia-based restorations cemented with RMGIC and compare them with those cemented with SAC.

METHODS

Cases of full-coverage zirconia-based restorations cemented with either RMGIC or SAC between March 2016 and February 2019 were evaluated in this study. The clinical outcomes of the restorations were analyzed according to the type of cement used. In addition, cumulative success and survival rates were evaluated according to the cement and abutment types. Non-inferiority, Kaplan-Meier, and Cox hazard tests were conducted (α=.05).

RESULTS

A total of 288 full-coverage zirconia-based restorations (natural teeth, 157; implant restorations, 131) were analyzed. Loss of retention occurred in only one case; a single-unit implant crown cemented with RMGIC, which decemented 4.25 years post-restoration. RMGIC was non-inferior to SAC in terms of loss of retention (<5%). For single-unit natural tooth restorations, the four-year success rates in the RMGIC and SAC groups were 100% and 95.65%, respectively (p=.122). For single-unit implant restorations, the four-year success rates in the RMGIC and SAC groups were 95.66% and 100%, respectively (p=.365). The hazard ratios of all the predictor variables, including cement type, were not significant (p>.05).

CONCLUSIONS

Cementation of full-coverage zirconia restorations of both natural teeth and implants using RMGIC and SAC yields satisfactory clinical outcomes. Furthermore, RMGIC is non-inferior to SAC in terms of cementation success.

CLINICAL SIGNIFICANCE

Cementation with RMGIC or SAC for full-coverage zirconia restorations has favorable clinical outcomes in both natural teeth and implants. Both RMGIC and SAC have advantages in the cementation of full-coverage zirconia restorations to abutments with favorable geometries.

Microleakage of thin-walled monolithic zirconia and polymer-containing CAD-CAM crowns

STATEMENT OF PROBLEM

Monolithic restorations facilitate computer-aided design and computer-aided manufacturing (CAD-CAM) processability and provide thin-walled restorations, which require less tooth reduction. For the long-term success of these restorations, their durable sealing is important. However, data in this regard are sparse.

PURPOSE

The purpose of this in vitro study was to investigate the microleakage of monolithic complete crowns made from current CAD-CAM materials after mastication simulation.

MATERIAL AND METHODS

Sixty-four identical test specimens (crown and tooth) were milled based on corresponding standard tessellation language data sets: one for the crowns and another for the human molar teeth. Four CAD-CAM restoration materials were investigated: 2 polymer-containing materials, Brilliant Crios (BC) and Vita Enamic (VE), and 2 zirconia materials, ultra-high-translucent Nacera Pearl Q³ Multi-Shade (ultraHT) and high-translucent Nacera Pearl Multi-Shade (HT). The crowns were adhesively luted to the CAD-CAM milled human molars with 1 of 3 luting systems: OneCoat7Universal and DuoCem (BC); A.R.T.Bond and DuoCement (VE); or EDPrimer/Panavia F2.0 (ultraHT and HT). The specimens were divided in 2 subgroups, and 2 different mastication simulations were applied: normal function (NF) and bruxism (B). A dye penetration test was used to detect microleakage, and the specimens were sectioned. A digital microscope (Zeiss) was used for analysis and to calculate the percentage of leakage in relation to the height of the tooth. Data were subjected to the Mann-Whitney and Kruskal-Wallis tests (α=.05).

RESULTS

Microleakage was identified in all groups. VE reported the highest leakage with a mean of 13.0%, followed by ultraHT (4.8%), HT (3.6%), and BC (3.0%). No significant difference was detected between the 2 simulation programs (normal function and bruxism). However, VE and the zirconia group HT exhibited a significant difference (P<.014), whereas no significant difference was noted among the zirconia groups or the polymer-containing groups BC and VE.

CONCLUSIONS

Thin-walled restorations made of CAD-CAM composite resin and zirconia exhibited reduced microleakage compared with the polymer-containing ceramic. Thus, from the specific viewpoint of microleakage, CAD-CAM composite resins and zirconia seem to be suitable materials for thin-walled complete crowns.

Effect of tooth preparation design on marginal adaptation of composite resin CAD-CAM onlays

STATEMENT OF PROBLEM

Although different preparation designs have been proposed for onlays fabricated by computer-aided design and computer-aided manufacturing (CAD-CAM), their effect on marginal adaptation is unclear.

PURPOSE

The purpose of this in vitro study was to investigate the effect of tooth preparation designs on the marginal and internal adaptation of ceramic-reinforced composite resin CAD-CAM onlays.

MATERIAL AND METHODS

A traditional preparation with a heavy chamfer on the functional cusp and a contrabevel on the nonfunctional cusp and a shoulder preparation with equal reduction on all cusps were used for mesial-occlusal-distal (MOD) onlay preparations. Ceramic-reinforced composite resin onlays were designed and milled based on the scanned prepared teeth. A digital silicone replica technique was used to determine marginal discrepancies between preparations and onlay restorations. A total of 100 numeric distances (representations of the fit in each region) were measured in 3 distinct regions: the buccal margin, lingual margin, and internal area. Independent Student t tests were used to determine significant differences (α=.05).

RESULTS

Traditional preparation designs resulted in significantly smaller overall discrepancies (50.9 ±0.5 μm and 139.1 ±5.4 μm, P<.001) and smaller marginal discrepancies in the buccal (49.7 ±1.4 μm and 135.8 ±2.2 μm, P<.001) and lingual areas (47.1 ±1.0 μm and 133.4 ±1.1 μm, P<.001).

CONCLUSIONS

The marginal adaptation of ceramic-reinforced composite resin CAD-CAM onlays was affected by the preparation design. The traditional preparation design offered better marginal adaptation; therefore, it is recommended in clinical practice.