Marginal Discrepancy Research Articles

Marginal Discrepancy and Internal Fit of 3D-Printed Versus Milled Laminate Veneers: An In Vitro Study

The clinical success of laminate veneers depends upon their marginal discrepancy (MD) and internal gap (IG). This study aims to compare and evaluate the MD, overall discrepancy (OD), absolute marginal discrepancy (AMD), and IG of 3D-printed (Varseosmile TrinQ and Varseosmile Crown Plus) and computer-aided design and manufacturing (CAD/CAM)-milled (Brilliant Crios) laminate veneers using cone-beam computed tomography (CBCT). Thirty maxillary central incisors were prepared and divided randomly into three groups (n = 10). All teeth were scanned for veneer fabrication: Group PVT teeth with 3D-printed Varseosmile TrinQ, Group PVC teeth with 3D-printed Varseosmile Crown Plus, and Group BCM teeth with Brilliant Crios milled veneers. The specimens with respective veneers were scanned using CBCT, and the sectional images were measured for IG, MD, OD, and AMD. The mean values for MD recorded were 0.27, 0.31, and 0.40 for PVT, PVC, and BCM respectively). The mean values for IG recorded were as follows: PVT group—0.24, PVC group—0.28, and BCM group—0.39, and those for OD were as follows: PVT—0.22, PVC—0.32, and BCM—0.41. Intragroup significance was observed for IG and OD (p = 0.001). Findings revealed that milled veneers have a higher IG and MD than 3D-printed veneers, making them less clinically acceptable.

Trueness and adaptation of screw-retained implant-supported monolithic zirconia crowns fabricated using 3-dimensional gel deposition

Implant-supportedmonolithic zirconia restorations manufactured using the additive 3-dimensional (3D) gel deposition technique have been introduced. However, studies determining the trueness and adaptation of implant-supported crowns made with the technique are lacking. The purpose of this in vitro study was to evaluate the trueness and adaptation of implant-supported zirconia crowns fabricated using additive 3D gel deposition in comparison with zirconia crowns made with the widely used subtractive milling technique. Crowns were fabricated for wide-diameter titanium implants and wide-neck abutments. Self-glazed zirconia (SGZ) crowns were fabricated using 3D gel deposition (n=10) and from 2 brands of zirconia blanks, Wieland and Upcera, using subtractive milling (WMZ and UMZ, n=10). All crowns were digitalized by a scanner, and then 3D deviation analysis was applied. The trueness was assessed by root mean square (RMS). Marginal and internal adaptations were evaluated using the direct-view technique (DT) and replica technique (RT). The results were analyzed by using the 1-way ANOVA and Kruskal-Wallis statistical tests (α=.05). The RMS and marginal discrepancy of SGZ exhibited the lowest values among the 3 groups (P<.05), and the 2 types of milled zirconia crowns had comparable RMS and marginal discrepancy values (P>.05). The internal discrepancy values of SGZ were significantly lower than those of WMZ and UMZ in all regions (P<.05). Compared with the WMZ, UMZ showed comparable internal discrepancy values in the axial and axio-occlusal transition regions (P>.05) but had significantly lower internal discrepancy value in the occlusal region (P<.05). The adaptation of 3 types of wide-diameter implant-supported zirconia crowns can meet the clinical requirements. Compared with the subtractive milling process, 3D gel deposition produced implant-supported zirconia crowns with improved trueness and adaptation.

Comparative Analysis of Adaptation of Conventional and Printable Complete Denture Bases to the Underlying Casts - An In Vitro Stereomicroscopic Study.

Properly adapted complete denture bases will have adequate retention to the underlying oral mucosa. With technological advancement, there are various techniques of fabrication of complete dentures. There are studies regarding the marginal adaptation of conventional and CAD-CAM denture bases, but there is not enough research comparing the marginal adaptation and polymerisation shrinkage of conventional and 3D printed complete denture bases. In vitro study using stereomicroscopy to determine the marginal discrepancy between the denture base and the cast. Twelve gypsum casts were taken and divided into conventional and 3D-printed groups. Conventional denture bases were fabricated by adapting wax of 2 mm thickness which was subsequently processed whereas 3D printed bases were designed and the standard tessellation language (STL) files were used to print the denture bases. Three points were marked at the mid-palatal line and on both maxillary tuberosities. Digital images were then captured at the marked regions and were used to measure the maximum gap between the cast and denture base at the marked regions. Data were analysed using an independent t-test and one-way ANOVA. Conventional dentures had a significantly lesser marginal discrepancy than 3D printed dentures (P = 0.000). The left maxillary tuberosity showed the highest marginal discrepancy, significantly different from mid-palatal and right tuberosity sites. Conventional dentures perform better than their counterparts in terms of adaptation. This accurate adaptation is vital for the retention of the complete denture.

EVALUATING THE MARGINAL DISCREPANCY AND SURFACE ROUGHNESS OF CAD - CAM MILLED VS 3D PRINTED PROVISIONAL CROWNS - AN INVITRO STUDY

Aims &amp;Objectives: To evaluate Marginal discrepancy and Surface roughness of CAD-CAM Milled and 3D Printed provisional crowns after subjecting them to thermocycling. Materials and Methods: A stainless-steel metal die with ANSI/ADA specifications had been fabricated for the study. It was scanned with an intraoral scanner and the data was sent to VHF S5M CAD CAM milling and R3Pro printing machine. A total of 10 samples Milled Group A(n=10) and 10 Printed Group B(n=10) provisional crowns were fabricated from PMMA material using the scanned data. The temperatures for thermocycling are 37ºC and 60ºC. Each group is subdivided into two subgroups(n=5) based on thermocycling temperatures. The timeduration selected for Thermocycling was 7,14 and21 days. Marginal discrepancy was measured by using Stereomicroscope and Surface roughness was measured with Profilometer. Results: Marginal discrepancy values were greater in CAD CAM milled crowns(141.47 µm) than in Printed crowns(109.87 µm) at 60ºC after a time-period of 21days.Surface roughness values were higher in Milled crowns(3.915µm) than in CAD CAM Printed crowns(3.817µm) at 60ºC for a given time duration of 21days. One-way ANOVA statistical analysis was done. The mean marginal gap of CAD CAM Milled crowns was statistically significant than Printed crowns(p&gt;0.05). Conclusion: Printed provisional restorationshad better Marginal accuracythan CAD CAM Milled provisional crowns. Surface roughness was higher in CAD CAM Milled crowns than in Printed provisional restorations.

Effect of Cementation and Thermomechanical Aging on the Marginal Adaptation of Veneered and Monolithic Zirconia

Objective: The objective of current study was to evaluate the marginal discrepancy of a manually veneered CAD/CAM zirconia and two different monolithic CAD/CAM zirconia all-ceramic crowns; before and after cementation; before and after artificial aging by using a chewing simulator. Methods: A total of 36 specimens were divided into 3 groups (n=12) and crown restorations were fabricated by using 3 different type of zirconia materials for each group: Group MZ1: monolithic zirconia crowns (GC initial), Group MZ2: monolithic zirconia crowns (InCoris TZI), Group BZ: bilayered zirconia crowns; zirconia core (InCoris ZI) veneered with a low-fusing glass-ceramic. The specimens were duplicated using epoxy resin before and after cementation and after thermo-mechanical fatigue. The marginal adaptations of replicated specimens were evaluated at six points. The margins were evaluated under a scanning electron microscope. Statistical analysis was performed using SPSS. Tukey HSD test were used to investigate the differences between the three types of zirconia crown restorations. Statistically significant difference was determined at (p

EVALUATING THE MARGINAL FIT OF GALVANOCERAMIC INLAYS: IS IT CLINICALLY ACCEPTABLE?

Purpose: The aim of this study was to investigate the marginal adaptation of galvanoceramic inlay comparing two different ceramic inlays used in dental practice. Materials and methods: Class II inlay cavity was prepared on an ivorine mandibular left first molar and a metal master die was produced from stainless steel. Using electroforming machine, fifteen galvanoformed copings were produced firstly, and then galvanoceramic inlays were obtained by firing feldspathic porcelain on them. For comparison with ceramic inlays, two different groups were prepared from lithium disilicate and alumina ceramic. The absolute marginal discrepancy of galvanoformed copings and three different inlay restorations were measured onto the master die in described 16 different reference points by scanning electron microscope. Data obtained from the measurements were statistically analysed using paired t-test and one-way analyses of variance (α=.05). Results: The galvanoceramic inlays showed a significantly higher marginal discrepancy than other ceramic inlays (P

Identifying marginal adaptation discrepancies of lithium disilicate crowns using seven different vertical X‐ray angulations

AbstractPurposeTo study the effect of different vertical angulations on the ability to radiographically assess vertical marginal discrepancies of lithium disilicate crowns.Materials and MethodsTwenty‐one lithium disilicate crowns were fabricated for three different prepared natural teeth: incisor, canine, and premolar. Vertical marginal discrepancies ranging from 0 to 300 µm were intentionally created. The seated crowns were radiographed using seven different vertical angulations, totaling 147 images. Thirty experienced evaluators scored each image for marginal discrepancy, and values were statistically analyzed.ResultsSignificant differences in the ability to accurately assess marginal discrepancies from radiographs were observed for the study factors of angulation, tooth type, and degree of marginal discrepancy (p &lt; 0.001).ConclusionsThe radiographic interpretation of the marginal discrepancies of lithium disilicate crowns is significantly affected by the dimension of the marginal discrepancy. Specifically on premolar crowns, it is significantly affected by different vertical angulations of the X‐ray beam. When evaluating marginal discrepancy on lithium disilicate crowns radiographically, vertical beam angulation within ±10° to the cemento‐enamel junctionCEJ plane is recommended.

Turbulent impinging air jet for cooling the heated surface

The present work deals with the experimental and numerical study of steadystate conjugate heat transfer during impingement of turbulent air jet over a heated stainless steel. The plate is heated using copper heater located at the middle. The temperature field is measured using an infrared camera and compared with the numerical simulations. Numerical simulations are performed using three-dimensional finite volume based formulation. The turbulence shear-stress transport (SST) is modeled using k−ω model based on the Reynolds averaged Navier Stokes (RANS) equations. The numerical simulations are in good agreement with the experimental data with marginal discrepancy in the steel plate region due to the contact thermal resistance between steel and copper. It is observed that the local Nusselt number increased in the stagnation region with increasing velocity of the impinging turbulent flow and practically unaltered in the region of the steel plate.

Evaluation of vertical marginal discrepancy and load-to-failure of monolithic zirconia and lithium disilicate laminate veneers manufactured in different thicknesses

ObjectivesThis study aimed to evaluate the feasibility of monolithic zirconia laminate veneers (MZLV) compared to lithium disilicate laminate veneers (LDLV).Materials and methodsSixty resin replicas, each prepared with depths of 0.5 mm, 0.7 mm, and 1 mm, were produced using a 3D printer from acrylic teeth. Laminate veneers of these thicknesses were milled from pre-sintered monolithic zirconia (3rd generation) and lithium disilicate blocks. The intaglio surface of MZLV was treated with air abrasion using 110 μm diameter silica-modified aluminium oxide particles and ceramic primer, while LDLV was etched with etchant gel and treated with the ceramic primer before cementation with resin cement. Vertical marginal discrepancy (VMD) was assessed using a stereomicroscope, and a load-to-failure test was conducted using a universal testing machine. Failure modes were evaluated macroscopically on fractured surfaces. Data were analysed statistically using Two-way ANOVA and Bonferroni correction (α = 0.05).ResultsLDLV samples exhibited significantly larger VMD compared to MZLV samples across all thicknesses, especially in cervical, palatal, and mean data. Within the LDLV group, load-to-fracture values for 0.7 mm and 1.0 mm thicknesses were similar, whereas for 0.5 mm thickness, it was significantly lower. In the MZLV group, load-to-fracture values were lower for 0.7 mm and 1.0 mm thicknesses compared to LDLV, but higher for 0.5 mm thickness.ConclusionsMaterial choice and restoration thickness significantly influence laminate veneer restorations’ success. MZLV generally exhibits superior vertical marginal fit compared to LDLV, with varying load-to-failure values across different thicknesses. Clinical management of debonding in MZLV is simpler compared to restoration fracture in LDLV.Clinical relevanceConsidering clinical factors, MZLV may be a preferable option to LDLV for this restoration with the thickness of 0.5 mm.

Cortical bone plate properties assessment using inversion of axially transmitted low frequency ultrasonic guided waves.

Over the past few decades, early osteoporosis detection using ultrasonic bone quality evaluation has gained prominence. Specifically, various studies focused on axial transmission using ultrasonic guided waves and have highlighted this technique's sensitivity to intrinsic properties of long cortical bones. This work aims to demonstrate the potential of low-frequency ultrasonic guided waves to infer the properties of the bone inside which they are propagating. A proprietary ultrasonic transducer, tailored to transmit ultrasonic guided waves under 500 kHz, was used for the data collection. The gathered data underwent two-dimensional fast Fourier transform processing to extract experimental dispersion curves. The proposed inversion scheme compares experimental dispersion curves with simulated dispersion curves calculated through the semi-analytical iso-geometric analysis (SAIGA) method. The numerical model integrates a bone phantom plate coupled with a soft tissue layer on its top surface, mimicking the experimental bone phantom plates. Subsequently, the mechanical properties of the bone phantom plates were estimated by reducing the misfit between the experimental and simulated dispersion curves. This inversion leaned heavily on the dispersive trajectories and amplitudes of ultrasonic guided wave modes. Results indicate a marginal discrepancy under 5% between the mechanical properties ascertained using the SAIGA-based inversion and those measured using bulk wave pulse-echo measurements.

Clinical performance of different composite materials in class II cavities bonded with universal adhesives.

To assess the clinical performance of two composite materials with two universal adhesives and a two-step self-etch adhesive on class II restorations for 18 months. Two hundred and fifty-two class II cavities were bonded with G-Premio Bond, Single Bond Universal, and Clearfil SE Bond 2. A nanohybrid composite (Filtek Z550 Universal) or a microhybrid composite (G-aenial Posterior) was used to fill the bonded cavities. World Dental Federation criteria were used to evaluate the restorations at 1 week, 6, and 18 months. Statistical analysis was performed using Friedman and Fisher's exact tests (α = 0.05). Retention loss and fracture were not observed in any restorations during the 18 months. The adhesives used showed no significant differences for all criteria examined (p > 0.05) regardless of composite material. After an 18-month follow-up, seven G-aenial Posterior and three Filtek Z550 Universal restorations presented slight marginal discrepancies, with no significant differences (p = 0.246). At 1 week, Filtek Z550 Universal (9.5%) led to significantly higher postoperative sensitivity compared with G-aenial Posterior (0.8%) (p = 0.001). Universal adhesives showed similar clinical performance to Clearfil SE Bond 2. The restorations with Filtek Z550 Universal had a relatively higher risk of postoperative sensitivity. Universal adhesives were clinically successful for 18 months. At 1 week, the type of composite material used significantly affected the occurrence of postoperative sensitivity.

Impact of Printing Orientation on the Accuracy of Additively Fabricated Denture Base Materials: A Systematic Review.

Printing orientation is one of the printing parameters that affect the properties of three-dimensional (3D)-printed resins. Different printing orientations and directions have been suggested; however, no clear and specific orientations are recommended in the literature in terms of the printing orientation effect on the accuracy and fit of 3D-printed removable dental prostheses. This review aimed to evaluate the effect of printing orientation on the fit and accuracy of 3D-printed removable dental prostheses. The PubMed, Scopus, and Web of Science databases were searched for published articles that investigated the effect of printing orientations on the accuracy and fit of the 3D-printed denture base. Full-length English published articles were searched between January 2010 and December 2023, which examined topics related to printing orientations, building angles, 3D printing, printing technology, accuracy, dimensional changes, internal fit, marginal integrity, marginal discrepancies, trueness, precision, and adaptation. Of the ten included studies, one investigated maxillary and mandibular denture bases, seven assessed maxillary denture bases, and two evaluated mandibular bases. Different printing orientations, ranging from 0° to 315°, were explored, with a higher prevalence of 0°, 45°, and 90°. The included studies utilized stereolithography and digital light processing printing technologies. High accuracy was observed at 45°, followed by 90. Additional struts and bars on the cameo surface increased the accuracy of the 3D-printed denture base. These results shows that printing orientation has a significant effect on the accuracy of 3D-printed resin, with 45° exhibiting the highest accuracy. In addition to the support structure, the density and position can impact the accuracy.

An In Vitro Study of Retention and Marginal Adaptation of Endocrowns With Different Intracoronal Depths.

Marginal adaptation and retention of endocrowns are crucial for the success and survival of endocrowns. This study aimed to investigate the effect of different materials and intracoronal depth on the retention and marginal adaptation of CAD/CAM fabricated all-ceramic endocrowns. Thirty-six mandibular premolar teeth with an average surface area of 64.49 mm2 were prepared to receive CAM/CAM fabricated endocrowns. Samples were divided randomly and equally into groups of lithium disilicate with 2 mm intracoronal depth (LD2), lithium disilicate with 4 mm intracoronal depth (LD4), polymer infiltrated ceramic network with 2 mm intracoronal depth (PICN2) and polymer infiltrated ceramic network with 4 mm intracoronal depth (PICN4). All endocrowns were cemented using ParaCore resin cement with 14N pressure and cured for 20 seconds. Fifty measurements of absolute marginal discrepancy (AMD) were done using a stereomicroscope after cementation. After 24 hours, all samples were subjected to thermocycling before the retention test. This involved using a universal testing machine with a crosshead speed of 0.5 mm/min and applying a load of 500N. The maximum force to detach the crown was recorded in newtons and the mode of failure was identified. Two-way ANOVA revealed that the AMD for PICN was statistically significantly better than lithium disilicate (p=0.01). No statistically significant difference was detected in the AMD between the two intracoronal depths (p=0.72). PICN and endocrowns with 4 mm intracoronal depth had statistically significant better retention (p<0.05). 72.22% of the sample suffered from cohesive failures and 10 LD endocrowns suffered adhesive failures. Within the limitations of this study, we found that different materials and intracoronal depths can indeed influence the retention of CAD/CAM fabricated endocrowns. Based on the controlled setting findings, PICN was found to have better retention and better marginal adaptation than similar lithium disilicate premolar endocrowns.

In Vitro Comparative Analysis of Digital Versus Conventional Impressions in Fixed Prosthodontics

ABSTRACT Background: In the realm of fixed prosthodontics, the transition from conventional to digital impressions has been a subject of ongoing debate. This study aims to provide a comparative analysis of digital versus conventional impressions in terms of accuracy and efficiency. Materials and Methods: Twenty patients requiring fixed prosthodontic treatment were selected for this study. Each patient received both digital and conventional impressions. The digital impressions were obtained using an intraoral scanner, while conventional impressions were taken using polyvinyl siloxane material. The impressions were then used to fabricate fixed prostheses for each patient. Accuracy was assessed through measurement of marginal fit using a standardized technique, and efficiency was evaluated based on time taken for impression procedures. Results: The mean marginal discrepancy for digital impressions was found to be 38 micrometers (±5), whereas for conventional impressions, it was 45 micrometers (±7). Additionally, the average time taken for digital impressions was 12 minutes, compared to 20 minutes for conventional impressions. Conclusion: Digital impressions demonstrated superior accuracy and efficiency compared to conventional impressions in fixed prosthodontics.

A Surrogate Model of Heat Transfer Mechanism in a Domestic Gas Oven: A Numerical Simulation Approach for Premixed Flames

This paper introduces an innovative analytical model to compute flame velocities and temperatures within a premix burner in a domestic gas oven. This model significantly streamlines the heat transfer simulation process by simplifying the modeling of the thermo-chemical energy release during combustion, effectively reducing complexity and computation time. Accelerated solutions are essential at the initial design stages when comparing the effect of the oven parameter variation on the overall performance. The validation of the proposed analytical model involved experimental assessments of the temperature of the false bottom plate in a natural gas oven. The resulting data were then compared against CFD simulations performed utilizing the proposed model. The results revealed a marginal discrepancy of 4% between the experimental measurements and the outcomes generated by the model. Simulations were executed under differing conditions, encompassing scenarios with and without radiation effects. This exploration identified natural convection as the predominant heat transfer mechanism, with heat radiation contributing only modestly to the heating of the false bottom plate. Among its advantages, the proposed model offers a notable reduction in the numerical complexity of the modeling of the combustion process. Furthermore, its straightforward integration into numerical simulations involving premixed flames underscores its practical utility and versatility in evaluating design performance at the early stages of the design. Highly accurate models can be left for the final oven configuration validation.

Accurate Density Prediction of Sesquiterpenoid HEDFs and the Multiproperty Computing Server SesquiterPre.

Accurate and rapid evaluation of density is crucial for evaluating the packing and combustion characteristics of high-energy-density fuels (HEDFs). This parameter is pivotal in the selection of high-performance HEDFs. Our study leveraged a polycyclic compound density data set and quantum chemical (QC) descriptors to establish a correlation with the target properties using the XGBoost algorithm. We utilized a recursive feature elimination method to simplify the model and developed a concise and interpretable density prediction model incorporating only six QC descriptors. The model demonstrated robust performance, achieving coefficients of determination (R 2) of 0.967 and 0.971 for internal and external test sets, respectively, and root-mean-square errors (RMSE) of 0.031 and 0.027 g/cm3, respectively. Compared to the other two mainstream methods, the marginal discrepancy between the predicted and actual molecular densities underscores the model's superior predictive ability and more usefulness for energy density calculation. Furthermore, we developed a web server (SesquiterPre, https://sespre.cmdrg.com/#/) that can simultaneously calculate the density, enthalpy of combustion, and energy density of sesquiterpenoid HEDFs, which greatly facilitates the use of researchers and is of great significance for accelerating the design and screening of novel sesquiterpenoid HEDFs.

Clinical performance of posterior restorations using a universal adhesive over moist and dry dentin: A 36-month double-blind split-mouth randomized clinical trial

ObjectivesTo evaluate the influence of dentin moisture on the clinical behavior of a universal adhesive on posterior teeth after 36 months of follow-up. MethodsForty-five patients participated in this study. Following a split-mouth design, three operators placed 90 Class I/Class II restorations over moist dentin (MD) or dry (DD) (n = 45) with resin composite (Filtek Bulk Fill) and a universal adhesive used in the etch-and-rinse mode (Single Bond Universal). Each restoration was evaluated according to the FDI and USPHS criteria (postoperative sensitivity, fracture and retention, marginal staining, marginal adaptation, and recurrence of caries) at baseline and after 6-, 12-, and 36 months. For statistical analysis, Kruskal Wallis analysis of variance rank (α = 0.05) and Kaplan-Meier survival analysis were used. ResultsNo significant difference between groups was observed in each FDI criterion after 36 months of clinical evaluation (p > 0.05). The retention rates (confidence interval 95 %) were 97.37 % (86.5 - 99.5) for both MD and DD without significant difference between them (p > 0.05). Eight restorations (MD = 4; DD = 4) showed minimal marginal staining defects (p > 0.05). Two restorations were lost (MD = 1; DD = 1). Fifteen restorations (MD = 8; DD = 7) presented minor marginal discrepancies according to the FDI criteria (p > 0.05). ConclusionThe clinical performance of the universal adhesive when applied in etch-and-rinse mode was not influenced by dentin moisture in posterior bulk-fill composite restorations. Clinical significanceThe level of dentin moisture appears not to influence the clinical efficacy of a universal adhesive when applied using the etch-and-rinse technique in posterior composite resin restorations.

CAD-CAM and heat-press: Comparison of internal and marginal fit of lithium disilicate copings.

The aim of this in vitro study is to compare the performance of digital and conventional methods in the manufacture of single copings in terms of the internal and marginal fit. Twenty-four prefabricated titanium Cone Morse Exact abutments of the lateral anatomical type were used to manufacture 24 lithium disilicate copings in the CAD-CAM Ceramill (n = 12) and heat-press (n = 12) systems. The copings were cemented using a self-adhesive resin cement (RelyX U-200; 3M ESPE) and then cut vertically. The cement line was photographed using an optical microscope at ×100 and ×200 magnification and then the internal and marginal regions were measured. The mean values of fits, for the CAD-CAM and heat-press techniques, respectively, were (μm): angular regions, 81.8 and 75.3; linear regions, 63.1 and 60.1; incisal regions, 171.1 and 114.7; marginal discrepancy, 74.1 and 75.2; and absolute marginal discrepancy, 99.5 and 96.2. MANOVA test showed that there is an effect of the techniques on the regions (p < .05). The effects of laboratories and the interaction between laboratories and techniques on the regions were not statistically significant (p > .05). The techniques evaluated presented clinically acceptable results for the marginal fit. However, the conventional method performed better for the internal fit. RESEARCH HIGHLIGHTS: Scientific evidence regarding the methods of making prosthesis can help the dental professional in decision-making. Digital and conventional methods is both good in the manufacture of single copings in terms of the internal and marginal fit.

Evaluation of Complications Associated with Fixed Partial Denture: A Prospective Study.

To assess complications, survival rates, and patient-reported outcomes associated with fixed partial dentures (FPDs). A cohort of 146 subjects, aged 18 and above, requiring FPD were recruited. Following comprehensive dental examinations, FPDs were fabricated. Complications, survival rates, and patient-reported outcomes were evaluated at 3, 6, 12, and 24 months. Complications such as marginal discrepancies and framework fractures showed low frequencies over short-, mid-, and long-term intervals. Survival rates were high at 98.6%, 96.2%, 93.7%, and 91.1% at all intervals, respectively. Patient-reported outcomes indicated a mean comfort level of 8.2 with speech difficulties (8.2%) and hygiene challenges (4.8%). Overall satisfaction was high, with a mean score of 9.0. This study provided evidence of favorable outcomes with low complication rates, high survival rates, and positive patient-reported experiences associated with FPDs.

Effect of Luting Materials on the Accuracy of Fit of Zirconia Copings: A Non-Destructive Digital Analysis Method.

The marginal accuracy of fit between prosthetic restorations and abutment teeth represents an essential aspect with regard to long-term clinical success. Since the final gap is also influenced by the luting techniques and materials applied, this study analyzed the accuracy of the fit of single-tooth zirconia copings before and after cementation using different luting materials. Forty plaster dies with a corresponding zirconia coping were manufactured based on a single tooth chamfer preparation. The copings were luted on the plaster dies (n = 10 per luting material) with a zinc phosphate (A), glass-ionomer (B), self-adhesive resin (C), or resin-modified glass-ionomer cement (D). The accuracy of fit for each coping was assessed using a non-destructive digital method. Intragroup statistical analysis was conducted using Wilcoxon signed rank tests and intergroup analysis by Kruskal-Wallis and Mann-Whitney U tests (α = 0.05). Accuracy of fit was significantly different before/after cementation within A (0.033/0.110 µm) and B (0.035/0.118 µm; p = 0.002). A had a significantly increased marginal gap compared to C and D, and B compared to C and D (p ≤ 0.001). Significantly increased vertical discrepancies between A and B versus C and D (p < 0.001) were assessed. Of the materials under investigation, the zinc phosphate cement led to increased vertical marginal discrepancies, whereas the self-adhesive resin cement did not influence the restoration fit.