Multicenter Prospective Clinical Study on Chairside-Fabricated Partial Crowns: 5-Year Results for Lithia-Zirconia Glass-Ceramic Restorations.

OBJECTIVES: Clinical evaluation of chairside-fabricated lithia-zirconia glass-ceramic (LZGC) partial crowns (CCPCs) in a multicenter practice-based study. MATERIALS AND METHODS: Seventy-one patients were restored with 92 adhesively luted CCPCs (Cerec SW 4.2/Cerec MC XL/Celtra Duo) in three private dental clinics (C1-C3). Time-dependent (Kaplan-Meier) survival rates (SVR) and success rates (SCR) were calculated. The following possible covariates of SVRs and SCRs were evaluated in a Cox regression model: Restoration position (premolar/molar), luting material (Variolink/Calibra), and operator (C1-C3). RESULTS: Seventy-three CCPCs were placed in 59 patients and were included in the study (mean observational period: 58.0 ± 15 months). Four complete failures (two tooth fractures, one restoration fracture, and one endodontic failure) were recorded. All failures and interventions occurred in one of the three centers (5-year SCR: C1 + C2: 100%; C3: 71%; 95% confidence interval: [0.55; 0.87]). Additionally, three biological, and two technical complications required clinical intervention to maintain function, and all occurred in C3. Restorations placed in C1 and C2 showed a significantly reduced risk for failure/intervention (hazard ratio = 0.103, p = 0.026) compared with restorations placed in C3. CONCLUSIONS: LZGC CCPCs showed good five-year clinical performance. However, SVRs and SCRs were significantly influenced by the operator. Additional clinical data are required for a more detailed investigation of this effect.

Survival, technical and biological outcome of fixed tooth- and implant-supported restorations: A retrospective analysis of a patient cohort treated in an undergraduate dental education program.

OBJECTIVES: There is a paucity of data on the outcome of fixed tooth- and implant-supported porcelain-fused-to-metal (PFM) and ceramic-based (CB) restorations fabricated during undergraduate dental education. Therefore, this retrospective study examined the outcome of fixed restorations placed in patients participating in an undergraduate program. METHODS: Patient records were searched for data on fixed PFM and CB restorations. For these restorations, the functional period in situ and technical and biological complications, namely restoration fracture, decementation, screw loosening, secondary caries, and loss of vitality, were recorded. Periodontal parameters were also documented. Kaplan-Meier survival and complication estimates after 1 and 5 years were calculated for restoration types, materials, designs (veneered/non-veneered), cementation/retention modes and localizations with group sizes ≥ 15. Regression models were used to analyze the influence of demographic data and abovementioned restoration characteristics on restoration survival, technical and biological outcome. RESULTS: 1196 restorations with a mean observation time of 5 years were included in the analysis. The different restoration types exhibited survival rates of > 90.8% after 5 years, accompanied by a favorable biological outcome. However, monolithic resin-matrix or feldspathic ceramic restorations were found to have a higher fracture rate than lithium disilicate or zirconium dioxide ceramic restorations resulting in lower survival rates for these restorations. Additionally, resin-matrix ceramic restorations showed a higher decementation rate than lithium disilicate restorations. CONCLUSIONS: Fixed tooth- and implant-supported CB restorations fabricated from lithium disilicate and zirconium dioxide ceramics demonstrated better survival and lower complication rates than restorations fabricated from resin-matrix or feldspathic ceramics in an undergraduate dental education program. CLINICAL SIGNIFICANCE: Due to the more favorable outcome of CB restorations fabricated from lithium disilicate or zirconium dioxide ceramics, undergraduate dental education should focus on the application of these ceramics to increase restoration survival by reducing technical complications.

Long-term performance of ceramic in/-onlays vs. cast gold partial crowns - a retrospective clinical study.

OBJECTIVES: To assess the long-term clinical performance of ceramic in-/onlays (CIOs) and cast gold partial crowns (CGPCs) in posterior teeth in terms of success, survival, complications (biological, technical) and quality. MATERIAL AND METHODS: In a retrospective study, a total of 325 patients were recorded after up to 24.8 years (mean 13.9 ± 3.8 years) having (pre-)molars restored with CIO (Empress I, Ivoclar Vivadent, n = 161) and CGPC (Degunorm, DeguDent, n = 164) by supervised undergraduate students. A total of 296 restorations were assessed clinically and radiologically in healthy and endodontically treated teeth using modified United States Public Health Service (USPHS) criteria. Cumulative success and survival rates of the restorations were calculated using Kaplan-Meier estimates. Biological and technical complications were recorded. Status of oral health comprising caries risk and localized periodontitis were assessed. RESULTS: The cumulative success rates of CIOs were 92.1% and of CGPCs 84.2% after mean service times of 14.5 years. The annual failure rates of total service times were 0.5% in teeth restored with CIO (n = 155) and 0.7% in teeth restored with CGPC (n = 163). The cumulative survival rates of CIOs were 93.9% after a mean service time of 15.2 years and decreased to 91.7% after 23.5 years. The cumulative survival rates of CGPCs were 92.6% after a mean service time of 14.9 years and 91.8% after 23.5 years. Complications in CIOs (n = 149) were ceramic fracture (6.7%), secondary caries (4.7%), endodontic complication (2.7%) and tooth fracture (1.3%) compared to CGPCs (n = 147) with endodontic complication (8.8%), secondary caries (4.8%) and decementation (2.0%). Endodontically treated teeth restored with CIO or CGPC revealed significantly less often success compared with corresponding vital teeth (p = .02). CIOs and CGPCs revealed clinically and radiographically good and excellent qualities with 71.8% (107/149) and 68% (100/147) without any significant differences regarding type of restoration. CONCLUSIONS: Both CIOs and CGPCs achieved high survival rates up to 24.8 years when performed by supervised undergraduate students. The longevity of the restorations may benefit from the intraoral repair of accessible defects and, in case of pulp infection or necrosis, an adequate endodontic management. CLINICAL RELEVANCE: CIOs and CGPCs made by supervised undergraduate students are proper restoration types in posterior teeth in the long-term. An adequate preparation design, meticulous care in the inserting technique and constant biofilm removal due to proper oral hygiene combined with professional maintenance care are substantial. The clinical long-term performance was mostly limited by ceramic fractures in CIOs and endodontic complications in CGPCs.

Retrospective clinical study on the performance and aesthetic outcome of pressed lithium disilicate restorations in posterior teeth up to 8.3 years.

OBJECTIVES: Evaluation of cumulative survival and complication rate of monolithic lithium disilicate inlays and partial crowns performed by supervised undergraduate students up to 8.3 years of clinical service. MATERIALS AND METHODS: In this retrospective clinical study 143 lithium disilicate posterior restorations (IPS e.max Press) were examined according to the FDI criteria. A standardised questionnaire was used to determine patient satisfaction. The aesthetic outcome was evaluated by dentists and dental technicians using intraoral photographs. Data were descriptively analysed. Cumulative survival and success rates were calculated using Kaplan-Meier estimation. RESULTS: The cumulative survival rate of lithium disilicate restorations was 97.5% after a mean service time of 5.9 years and 95.0% after 8.3 years. The cumulative success rate decreased from 94.4% after 5.9 years to 30.7% after 8.3 years. Repairs were required for 7 restorations (4.9%), and 5 (3.5%) were classified as failures. The results of the questionnaire indicate a high level of patient satisfaction. The subjective aesthetics were assessed more critically by dental technicians compared to dentists. CONCLUSION: Lithium disilicate posterior restorations survived successfully up to 8.3 years when carried out by undergraduate students. CLINICAL RELEVANCE: Pressed lithium disilicate glass ceramic inlays and partial crowns are reliable treatment options in posterior teeth.

The influence of indirect bonded restorations on clinical prognosis of endodontically treated teeth: A systematic review and meta-analysis.

OBJECTIVE: The loss of the dental coronal portion following carious lesions or fractures leads to endodontic treatment with subsequent restoration to ensure correct anatomy and function. Recently, partial adhesive restorations have been widely proposed to increase the survival rate of endodontically treated teeth. The primary purpose of this review is to assess the failure rate of indirect partial adhesive restorations on endodontically treated teeth (ETT), considering the follow-up period. METHODS: The indications reported in the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analysis) were used to draft the present review. The study was constructed on PICO questions: population (patients who need indirect adhesive restorative treatment on endodontically treated teeth with onlay and overlay), intervention (onlay and overlay), control (patients with onlay and overlay on endodontically treated teeth) and outcome (failure rate and types of failure for onlay and overlay). The asked scientific question was: what are the failure rate and types of failure for adhesive indirect partial restorations on ETT? RESULTS: The overall failure rate that emerges is 0.087 with a ratio of 121/1254, I2 80 % p-value< 0.001. Moreover, by meta-regression with covariates the follow-up period reports a coefficient of 0.013 with a P-value< 0.001. In conclusion, the indirect partial restorations on endodontically treated teeth displayed overall acceptable outcomes in terms of success from 2 to 4 years after their placement with only 4.32 % of failure. Failures increase after 7 years up to 12-30 years with failure rates of approximatively 10.65 % and 20.94 %. The analysis of the included articles reporting the causes of restorations failures showed that 15.51 % of cases were related to the loss of dental element. SIGNIFICANCE: Besides the survival rates of indirect adhesive restorations on endodontically treated posterior teeth, it was highlighted that the majority of failures appeared restorable. Thus, partial restorations seemed able to prevent the ETT tooth loss.

Prospective clinical evaluation of chairside-fabricated zirconia-reinforced lithium silicate ceramic partial crowns-5-year results.

OBJECTIVES: A university-based randomized clinical study evaluated the 5-year performance of chairside-fabricated zirconia-reinforced lithium silicate (ZLS)-ceramic partial crowns. MATERIAL AND METHODS: Forty-five patients were restored with 61 chairside-fabricated ZLS-restorations (Cerec SW 4.2, Dentsply Sirona, Germany; Vita Suprinity, Vita Zahnfabrik, Germany). Deviating from the manufacturers' recommendations, restorations with reduced minimum material thicknesses (MMT) were fabricated: group 1, MMT = 0.5-0.74 mm (n = 31); group 2, MMT = 0.75-1.0 mm (n = 30). For luting, a self-adhesive cement (SAC) or a total-etch technique with a composite cement (TEC) was applied. Statistical evaluation was performed by time-to-event analysis (Kaplan-Meier). Possible covariates of the survival (SVR) and success rates (SCR), evaluated in a Cox regression model, were MMT, restoration position (premolar/molar), and cementation technique (SAC vs. TEC). RESULTS: Forty patients (54 restorations, premolars, n = 23; molars, n = 31) participated in the 5-year follow-up. Five losses due to ceramic fractures occurred in group 1 (n = 28) (SVR: 83.0% [95% confidence interval (CI): 0.71-0.96]). Group 2 (n = 26) showed no losses (SVR: 100%). The success rate for partial crowns placed on premolars was 100% and 69% (95% CI: 0.54-0.84) for molar restorations. Recementation was required in 4 restorations with SAC (SCR: 86% [95% CI: 0.73-0.99]; SCR-DC: 100%). Restorations in group 2 showed a significantly reduced risk of material fracture hazard ratio (HR) = 0.09, p = 0.0292) compared with the restorations in group 1. Molar partial crowns showed an increased risk for a clinical intervention (HR = 5.26, p = 0.0222) compared to premolar restorations. CONCLUSIONS: Material thickness and position of the restoration are risk factors influencing the survival and success rate of ZLS-ceramic partial crowns. CLINICAL RELEVANCE: Observation of an MMT of at least 0.75-1.0 mm for ZLS-ceramics is essential to avoid material-related fractures. CLINICAL TRIAL REGISTRATION: German Clinical Trails Register (trial number: DRKS00005611).

Longevity of lithium disilicate indirect restorations in posterior teeth prepared by undergraduate students: A retrospective study up to 8.5 years.

OBJECTIVES: To analyze retrospectively the clinical performance and survival of lithium disilicate inlays, partial crowns and crowns placed by undergraduate students. METHODS: 250 lithium disilicate posterior restorations (IPS™Emax Press) were evaluated. Mean service time was 6.6 years (79 months) with a maximum observation time of 8.5 years (102 months). Clinical performance was assessed using FDI Criteria. Descriptive statistics were used to display the distribution of the criteria. Success and survival of the restorations were calculated with the Kaplan Meier method. A Cox regression analysis was performed to detect influencing parameters for the survival or the success of the restorations. RESULTS: Survival and success rates of lithium disilicate indirect restorations were calculated at 6.6 years with 96.3 % and 93.8 %, respectively. After 8.5 years the survival rate was calculated with 94 % and the success rate with 83.8 %. 10 out of 250 restorations (4%) failed, while the main reasons for failure were fracture of material, debonding/loss of restoration, endodontic complications as well as recurrence of caries. A Cox regression analysis failed to show a correlation between restoration failure and the experience level of the students, an existing root canal treatment, type of tooth, bruxism or the use of rubber dam. CONCLUSIONS: Lithium disilicate indirect posterior restorations demonstrate a high success and survival rate after a mean service of 6.6 years when placed by undergraduate students with different levels of experience. Co-factors influencing the survival or success rate of these restorations could not be identified. CLINICAL SIGNIFICANCE: Lithium disilicate restorations show a good clinical performance up to 8.5 years when prepared by undergraduate students.

Clinical Evaluation of Chairside-Fabricated Partial Crowns Made of Zirconia- Reinforced Lithium Silicate Ceramic - 2-Year-Results.

INTRODUCTION: In a prospective study, the clinical performance of chairside-fabricated partial-crowns made of zirconia-reinforced lithiumsilicate (ZLS)-ceramic was evaluated after 2 years. MATERIALS AND METHODS: 45 patients (28 female/17 male) underwent restoration with 61 chairside-fabricated ZLS partial-crowns on vital premolars and molars. In variation from the manufacturer's recommendations (minimum material thickness (MMT)=1.0 mm), partial-crowns with reduced material thicknesses were fabricated: group 1, MMT=0.5-0.74 mm (n=31); group 2, MMT=0.75-1.0 mm (n=30). The restorations were luted with either a self-adhesive cement (SAC) or the total-etch technique using a dual-curing composite cement (DC). The MMT and cementation technique (SAC vs. DC) were evaluated as possible covariates of the time-dependent survival (SVR) and success rate (SCR) using univariate log-rank-tests. RESULTS: Forty-four patients with 59 restorations participated in the 2-year follow-up examinations. In group 1 (n=31), there were 2 losses due to ceramic fracture (SVR: 94.0% (95% confidence interval (CI): 0.85-1)). In group 2, no losses were documented (SVR: 100%). In 2 restorations cemented with SAC, recementation was necessary (overall SCR: 93% (CI: 0.87-1)). CONCLUSION: To avoid early material-related fractures, observing the recommended minimum thickness of 1.0 mm is essential. However, further validation of these results in studies with longer observational periods is required.

Clinical evaluation of chairside-fabricated partial crowns composed of zirconia-reinforced lithium silicate ceramics: 3-year results of a prospective practice-based study.

OBJECTIVES: Prospective practice-based clinical evaluation of chairside fabricated monolithic partial crowns composed of zirconia-containing lithium silicate (ZLS) ceramic material. MATERIALS AND METHODS: Between October 2013 and September 2014, 71 patients were restored with 92 partial crowns on vital or sufficiently endodontically treated teeth. The monolithic restorations were fabricated chairside (Cerec SW 4.2/Cerec MC XL) from a glaze-fired ZLS ceramic material (Celtra Duo, Dentsply Sirona, Bensheim, Germany). Adhesive cementation was performed using the total-etch technique with one of two dual-curing composite materials. Modified United States Public Health Service parameters were evaluated annually; moreover, the parameters "time-dependent survival" (in situ criterion) and "success rates" (event-free restorations) were evaluated according to Kaplan-Meier analysis. RESULTS: Sixty-nine patients with 17 premolar and 71 molar partial crowns attended annual follow-up examinations (observational period: 36.0 ± 5.7 months). Two complete failures were recorded and were caused by a tooth fracture (at 30 months) and a restoration fracture (at 38 months), (3-year survival rate: 99%; 95% confidence interval (CI 95%): [0.97;1]). One clinical intervention was necessary (endodontic treatment) to maintain function (3-year success rate: 98%; (CI95%: [0.95:1]). CONCLUSIONS: Chairside-fabricated ZLS partial crowns show a good initial clinical performance. However, to further evaluate this new material, clinical data from studies with longer observational periods are required. CLINICAL SIGNIFICANCE: Based on this mid-term evaluation, ZLS ceramics appear to be a promising alternative material for the chairside fabrication of adhesively luted monolithic posterior restorations with a low risk of material-related complications.

Effect of restoration material on stress distribution on partial crowns: A 3D finite element analysis.

BACKGROUND/PURPOSE: Various restoration materials have been used to restore as onlay materials to restore highly defected molar teeth. Different mechanical and physical properties of these materials may affect the success or survival of the restoration. The purpose of this study was to evaluate the restoration materials effects on stress distribution. MATERIALS AND METHODS: Three dimensional finite element analysis (FEA) was used to evaluate the stress concentrations and distributions at the restoration and the tooth. Maxillar first molar tooth constructed to evaluate the stress distribution and concentration levels at the restorations and the tooth structure. Two kinds of restoration materials, bulkfill composite and conventional hybrid composite was evaluated for direct method, while full ceramic and indirect composite was used for indirect method. A load of 200 N was applied on the restorations and stress levels were calculated by von Mises stress values. RESULTS: Highest stress concentration was observed at the ceramic restoration (3.77 GPa). Stress levels were 2.90 GPa for bulkfill composite and 2.14 GPa for direct and indirect composite. At the tooth structure the stress levels were 3.33 GPa, 3.18 GPa and 2.48 GPa for bulkfill, direct and indirect composites respectively. The lowest stress values was observed with the porcelain restoration (1.69 GPa). Stress concentrations at the adhesive system were 2.10 MPa for bulkfill composite, 1.35 MPa for direct and indirect composites and 1.25 Mpa for porcelain restoration. CONCLUSION: The restoration material affects the stress levels at the restoration and the tooth while the stress concentration areas remained nearly the same.

Restoration of incisal half with edge-up technique using ceramic partial crown in turner's hypoplasia: A case report.

This case report describes a rare treatment modality for Turner's hypoplasia done with a very conservative approach for the esthetic and functional problem of the defect. Diagnosis was made as Turner's hypoplasia of upper two central incisors with proximal caries. Treatment planning was done after considering many factors such as conservation of tooth structure, esthetics, occlusion and economy. Tooth preparation was done to receive Edge-up, all ceramic partial crowns for both the upper central incisors,using pressable all ceramic material and cemented with resin cement.