Marginal Fit Research Articles

Evaluation of the clinical application of personalized 3D printing and CAD/CAM resin crowns to replace stainless steel crowns in paediatric dentistry.

Children with dental caries are treated with stainless steel metal crowns (SSC), but the aesthetics and precision still need to be improved. Currently, both 3D-printed resin crowns (PRC) and computer-aided design/computer-aided manufacture (CAD/CAM) resin crowns (CRC) meet the clinical requirements for crown applications in terms of strength, production time, cost, and aesthetics. This study replaced SSC with customized resin crowns by 3D printing and CAD/CAM. In this study, PRC, CRC, and SSC were used for incisor and molar restorations, and 60 crowns were made with 10 for each group. The fabrication efficiency, surface characteristics, marginal fit, and stability of the two different crowns were evaluated. PRC and CRC show superior color and surface characteristics, though production times are longer (5.3-12.4 times and 3.3-9.1 times, respectively) than for SSC (p < .05). They, however, can be completed within 80 min. Edge gaps for PRC and CRC are significantly lower (13.0-19.2 times and 13.0-13.7 times) than for SSC (p < .05). All materials exhibit good stability. The 3D-PRCs and CAD/CAM resin crowns may replace SSCs as a potential choice for clinical child caries.

Effect of cement space on marginal and internal fit of a zirconia core fabricated using by additive manufacturing

Effect of cement space on marginal and internal fit of a zirconia core fabricated using by additive manufacturing

3D-printed intracoronal restorations, occlusal and laminate veneers: Clinical relevance, properties, and behavior compared to milled restorations; a systematic review and meta-analysis.

To assess the feasibility of producing 3D-printed intracoronal restorations, thin and ultrathin veneers, and to compare their mechanical behavior, accuracy, biological, and stain susceptibility to the currently applied milled restorations. The databases were comprehensively searched for relevant records up to January 2024 without language restrictions. All studies that assessed 3D-printed partial coverage restorations including inlays, onlays, laminate, and occlusal veneers were retrieved. The web search yielded a total of 1142 records, with 8 additional records added from websites at a later stage. Only 17 records were ultimately included in the review. The included records compared 3D-printed; alumina-based- and zirconia ceramics, lithium disilicate ceramics, polymer infiltrated ceramics, polyetheretherketone (PEEK), resin composites, and acrylic resins to their CNC milled analogs. The pooled data indicated that it is possible to produce ultrathin restorations with a thickness of less than 0.2 mm. 3D-printed laminate veneers and intracoronal restorations exhibited superior trueness, as well as better marginal and internal fit compared to milled restorations (p < 0.05). However, it should be noted that the choice of materials and preparation design may influence these outcomes. In terms of cost, the initial investment and production expenses associated with 3D printing were significantly lower than those of CNC milling technology. Additionally, 3D printing was also shown to be more time-efficient. Using additive manufacturing technology to produce restorations with a thickness ranging from 0.1 to 0.2 mm is indeed feasible. The high accuracy of these restorations, contributes to their ability to resist caries progression, surpassing the minimum clinical threshold load of failure by a significant margin and reliable adhesion. However, before 3D-printed resin restorations can be widely adopted for clinical applications, further improvements are needed, particularly in terms of reducing their susceptibility to stains. 3D-printed intracoronal restorations and veneers are more time and cost-efficient, more accurate, and could provide a considerable alternative to the currently applied CNC milling. Some limitations still accompany the resin materials, but this could be overcome by further development of the materials and printing technology.

Effect of Different Sintering Procedures on Marginal and Internal Fit, Color, and Fracture Load of Monolithic Zirconia Fixed Partial Prosthesis.

The aim of this in vitro study is to investigate the effects of different sintering procedures on the fit, color parameters, and fracture load of monolithic fixed partial prosthesis. Metal model was scanned and fixed partial prosthesis was designed. Groups were created by fabricating fixed partial prosthesis by using four different sinterization procedures (Prettau-Standard (PST), Prettau-Slow (PSL), Ice-Speed (IS), Ice-Standard (IST), n=10). PST-PSL (Group P, N=20) and IS-IST (Group I, N=20) were colored with different coloring liquids. The marginal and internal fit were measured using the silicone replica method. CIELAB values of the samples were measured using a spectrophotometer. Then, for each sample, the die was obtained from polymethyl methacrylate. The specimens were cemented into dies and tested in a universal testing machine for fracture load. One-way ANOVA were performed to assess the effect of the sintering procedure on the marginal and internal fit, fracture load, and ∆E00, ∆L', ∆C', and ∆H' values of fixed partial prosthesis. PSL and PST groups showed significantly smaller internal and marginal fit compared to the IS group. Additionally, IST group internal fit values were significantly higher than Prettau groups. Sintering time reduction led to a decrease in ∆E00 values. Fracture loads values were not statistically significantly affected by the different sintering procedures in both brands. Different sintering procedures did not have a clinically significant effect on fit and fracture load. Different sintering procedures were found to have an impact on the color change of monolithic zirconia restorations.

Hot isostatic pressing as an alternative thermo-mechanical treatment for metallic full-arch implant-supported frameworks obtained by additive and subtractive manufacturing technology: Vertical and horizontal fit, screw removal torque, and stress analysis.

To assess vertical and horizontal fit, screw removal torque, and stress analysis (considered biomechanical aspects) of full-arch implant frameworks manufactured in Ti-6Al-4V through milling, and additive manufacturing Direct Metal Laser Sintering (DMLS) and Electron Beam Melting (EBM), and the effect of the thermo-mechanical treatment Hot Isostatic Pressing (HIP) as a post-treatment after manufacturing. Maxillary full-arch implant frameworks were made by milling, DMLS, and EBM. The biomechanical assessments were screw removal torque, strain-gauge analyses, and vertical and horizontal marginal fits. The vertical fit was assessed by the single-screw test and with all screws tightened. All frameworks were submitted to a standardized HIP cycle (920°C, 1000bar pressure, 2h), and the tests were repeated (α = 0.05). At the initial time, milled frameworks presented higher screw removal torque values, and DMLS and EBM frameworks presented lower levels of strain. Using the single-screw test, milled and DMLS frameworks presented higher vertical fit values, and with all screws tightened and horizontally, higher fit values were found for milled frameworks, followed by DMLS and EBM. After HIP, milling and EBM frameworks presented higher screw removal torque values; the lowest strain values were found for EBM. Using the single-screw test, milled and DMLS frameworks presented higher vertical fit values, and with all screws tightened and horizontally no differences were found. DMLS and EBM full-arch frameworks presented adequate values of screw removal torque, strain, and marginal fit, although the worst values of marginal fit were found for EBM frameworks. The HIP cycle enhanced the screw removal torque of milled and EBM frameworks and reduced the strain values of milled frameworks. The HIP represents a reliable post-treatment for Ti-6Al-4V dental prostheses produced by milling and EBM technologies.

The Influence of Ferrule Design and Pulpal Extensions on the Accuracy of Fit and the Fracture Resistance of Zirconia-Reinforced Lithium Silicate Endocrowns.

The study aimed to assess the marginal, axial, and internal adaptation, as well as the fracture resistance of zirconia-reinforced lithium silicate (ZLS) endocrowns with varying pulpal inlay extensions and marginal geometry. Sixty extracted maxillary first molar teeth were divided into six groups (n = 10) according to pulpal inlay extension and marginal configuration. The first three groups (J2, J3, and J4) utilized prepared teeth for endocrowns without ferrule design and 2 mm, 3 mm, and 4 mm pulpal extensions, respectively. The second three groups (F2, F3, and F4) utilized prepared teeth with 1 mm shoulder margins and 2 mm, 3 mm, and 4 mm pulpal extensions. The endocrowns were fabricated from ZLS blocks using CAD/CAM milling technology. After cementation, the specimens underwent thermal aging for 5000 cycles and were evaluated for marginal adaptation. Using a universal testing machine, the fracture resistance was tested under quasistatic loading (1 mm/min). Two-way ANOVA and the Tukey's post hoc test were employed for data analysis (p ≤ 0.05). The results of this study revealed that endocrowns without ferrule exhibited superior fracture strength than a 1 mm ferrule design p < 0.05, irrespective of the inlay depth. All designs with and without ferrule and all inlay depths showed clinically acceptable marginal and internal fit. The conventional endocrown design without ferrule and 2 mm inlay depth showed the lowest surface gap. The pulpal surface showed the highest discrepancy among all groups compared to the other surfaces. Endocrowns without ferrule are more conservative and have higher fracture strength than 1 mm ferrule designs; extending the inlay depth showed a significant increase in fracture resistance of the 1 mm ferrule design, but not for the conventional design without ferrule and 2 mm inlay depth. All groups exhibited a high auspicious fracture strength value for molar endocrown restorations.

RESTORATION OF CORONAL PART IN CHEWING TEETH WITH SIGNIFICANT LOSS OF HARD TISSUES BY POST AND CORE CROWN

The purpose of this study was to improve the quality of orthopedic treatment of hard dental tissues of chewing teeth destroyed below the level of the gums by a post and core crown using ashless modeling plastics.&#x0D; We examined 30 patients with severe destruction of the hard tissues of the crown portion of the teeth (IROPZ more than 80%) and concurrent periodontal diseases. A retrospective analysis revealed that teeth with deep subgingival defects restored by casts functioned as follows: for up to 1 year in 17 cases (14.2%), from 1 to 3 years in 36 cases (30.0%), from 3 to 5 years in 43 cases (35.8%), and for more than 5 years in 24 cases (20.0%).&#x0D; The results of a comparative evaluation of the effectiveness of tooth restoration with subgingival defects using ashless acrylic plastic "Modeplast" as a modeling material demonstrated the highest quality of such inserts, with most observed cases showing no signs of secondary caries. Complications, such as the dislodgement of metal inserts, were noted in 6.7% of cases, violation of marginal fit in 4.5%, and partial decementation of the structure in 8.3%. Incorrect positioning and suboptimal pin dimensions of the post and core crown occurred with approximately equal frequency: 3.5% and 3.2%, respectively. Destruction of the hard tissues of the tooth and caries relapse during restoration with metal inserts were noted in 13.3% and 29.1% of cases, respectively. Typical complications leading to tooth extraction included tooth root fractures (13.3%).&#x0D; The developed method of manufacturing post and core crowns using ashless acrylic plastic "Modeplast" at the modeling stage enables to gently remove tooth tissues and atraumatic fit of the post to the gums, prevents the accumulation of dental plaque and does not have a destructive effect on periodontal tissues.

CLINICAL STATE OF DIRECT RESTORATION OF SIDE TEETH IN ORTHODONTIC PATIENTS

Relevance. During long-term orthodontic treatment, there are favorable conditions for the development of dental caries and periodontal diseases.&#x0D; Aim of the study. Retrospective clinical evaluation of direct restorations of teeth in patients during treatment of orthodontic pathology with fixed appliances.&#x0D; Materials and methods. The condition of 227 direct photocomposite restorations of lateral teeth with localization on the occlusal and one of the contact surfaces and duration of functioning from 1 to 5 years was studied in 57 people who were treated with the use of fixed orthodontic equipment. Marginal fit, secondary caries and contact points were evaluated.&#x0D; Research results. In restorations with terms of 1-2 years, a violation of the marginal fit on the occlusal surface was found in 5 restorations (6.4% of their number with the given terms), on the vestibular and oral surfaces – in 7 (9%), in the area near the gums – in 10 restorations (12.8%). Secondary caries was detected on the vestibular surface in 2 restored teeth (2.6%), in the area near the gums – in 8 teeth (10.3%). There were violations of the contact point in 4 cases (5.1%). With terms of 4-5 years, in 3 restorations (10.3% of the number with these terms), violations of marginal fit were established on the occlusal surface, in 9 (31%) on the vestibular and oral surfaces, in 17 restorations (58.6%) – in the area near the gums. Secondary caries on the occlusal surface was found in 2 teeth (6.9%), on the vestibular and oral surfaces in 4 (13.8%), in the area near the gums – in 16 teeth (55.2%). Defects of the contact point were established in 19 cases (65.5%). Conclusions. In the conditions of orthodontic treatment with fixed equipment, the risk of developing disorders in photocomposite restorations in the area near the gums of the contact surfaces of the lateral teeth increases significantly.

Comparing Zirconium Crown Marginal Adaptation in Preparations with Two Different Occlusal Reductions.

This study aimed to assess and contrast the effects on the vertical marginal fit of full contour CAD/CAM-generated monolithic zirconia crowns at pre- and post-cementation levels with various occlusal reduction schemes (planar and flat) and cements. Forty sound human maxillary first premolars were sampled for this study. The samples were divided into two main groups with twenty samples in each group according to the occlusal reduction scheme as follows: Group A included a chamfer finishing line design with a planar occlusal reduction scheme and Group B included a chamfer finishing line design with a flat occlusal reduction scheme. Each group was sampled into two subgroups (n = 10) based on the type of cement as follows: resin-modified glass ionomer cement (Fuji Plus) for subgroups A1 and B1, and a universal adhesive system (Duo Estecem II) for subgroups A2 and B2. Marginal gaps were tested in four indentations using a Dino light stereomicroscope (230×). Paired T-tests and Student's t-tests were used to analyze the data. Before cementation, subgroup A1 scored the lowest mean of vertical marginal gap values, while subgroup B2 scored the highest mean; following cementation, subgroup A1 scored the lowest mean of vertical marginal gap values, and subgroup B2 scored the highest mean of vertical marginal gap values. A chamfer finishing line design with a planar occlusal reduction scheme could be a preferable occlusal reduction scheme.

Comparative evaluation of marginal fit, internal fit and cement space of single unit lithium disilicate crown with shoulder finish line by two different methods of fabrication

Background The coming era will be governed by technology. Computer aided designing (CAD) &amp; computer aided manufacturing (CAM) dentistry is taking over the conventional dental practice establishing a benchmark in esthetics, quality and fit of the prosthesis. The fabrication of prosthesis by digital methods reduces the efforts in fabrication and time required for designing the prosthesis. Aim This protocol aims at checking the marginal fit, internal fit and cement space of lithium disilicate crowns by comparing the two different methods of fabrication. To evaluate and compare marginal fit, internal fit and cement space of single unit “lithium disilicate crown” with shoulder finish line with two different methods of fabrication. Methods The current study is the experimental study conducted at Sharad Pawar dental college and Hospital. The protocol has been approved by the Ethical institutional committee with ref.no.DMIHER(DU)/IEC/2023/851. All the 54 participants who will visit the O.P.D of department of prosthodontics crown &amp; bridge will be included in the study which will be conducted over a period of two years, the subjects will be informed about the research and written consent will be taken. The inclusion criteria for this study are patients aged 18-54 years in the need of full veneer maxillary incisors crown prosthesis. All the comparative results will be calculated with the help of stereomicroscope and descriptive statistics will be performed. Expected results The expected outcome or result proposed will be, the crown fabricated with CAD-CAM will give good fit compared to pressed method. Conclusions Finding the accuracy in the fit and cement space of lithium disilicate crowns by conventional and digital method of fabrication will help the prosthodontist to deliver good results.

Feasibility of images acquired using smartphone camera for marginal and internal fit of fixed dental prosthesis: comparison and correlation study

This study aimed to measure marginal and internal fit using images captured with both an optical microscope and a smartphone camera, comparing the fit measurement performance of these devices and analyzing their correlation. Working casts (with 10 posterior and 10 anterior teeth) created to fabricate fixed dental prostheses were used. These working casts were scanned using a desktop scanner (E1) to design an interim crown, and the designed interim crown was fabricated using a three-dimensional (3D) printer. Utilizing the silicone replica technique, the fabricated interim crown replicated the fit, which was then captured using both an optical microscope and a smartphone camera. The captured images were used to measure the marginal and internal fit according to the imaging device. Intraclass correlation coefficients (ICC) were used for reliability analysis according to the imaging device. Furthermore, the Wilcoxon signed-rank test was adopted for the comparative evaluation of the marginal and internal fit between the imaging devices (α = 0.05). The measurement results of the marginal and internal fit according to the optical microscope and smartphone camera did exhibit a significant difference (P < 0.05). The ICC between the two devices showed an “excellent” agreement of over 0.9 at all measurement points (P < 0.001). A smartphone camera could be used to obtain images for evaluating the marginal and internal fit.

Evaluation of periodontal parameters on abutment teeth rehabilitated with single-unit crowns: A 12-month follow-up

PurposeThis prospective study evaluated the effects of the metal-free crowns on the periodontal tissues of abutment teeth during a 12-month follow-up. Materials and Methods:A sample of 24 patients (N = 32 abutment teeth) who needed a single-tooth restoration were enrolled to receive either a metal-ceramic (n = 21) or lithium disilicate (n = 11). The single-unit crowns were evaluated at baseline, 3-and 12-month follow-up. The periodontal parameters were evaluated: plaque index (PI), gingival bleeding index (GBI), bleeding on probing (BOP), probing depth (PD), clinical attachment loss (CAL), radiographically and clinical crown fitting, bone resorption, and marginal finish lines. Statistical analyses were performed using the Exact Fisher and Mann-Whitney tests, and the Wilcoxon signed-rank test as a post hoc test for Friedman (95 % confidence interval). Results:The marginal finish line showed a statistical difference with a biomaterial type (p =.004). After a 12-months, a significant increase was observed in PI and mean PD for abutment teeth of metal-ceramic crowns. The metal-free crowns presented higher values for GBI and CAL (p2 < 0.05). Only distal cervical evaluation and dental biofilm formation in the abutment teeth showed a statistical difference between the groups at the 12-month follow-up. The supragingival margin metal-ceramic group revealed higher PI values (p2 = 0.005) between the period and the subgingival margin of both biomaterials showed greater GBI scores (p2 < 0.05). Conclusions:Metal-free crowns showed better periodontal outcomes compared to metal-ceramic crowns. Single-unit crown marginal location affects the periodontal tissue condition of the abutment teeth. The marginal fit was not changed regarding the biomaterial type.

In vitro effect of zirconia type on marginal and internal fit of a three-unit bridge.

In vitro effect of zirconia type on marginal and internal fit of a three-unit bridge.

Examination of the effect of aging process on marginal fit and fracture strength of temporary crowns prepared from different materials

AimThe aim of this study is to investigate the effect of the aging process on the marginal fit and fracture resistance of temporary crowns prepared using different materials. Materials and methodThe steel die to represent the maxillary first premolar used in this study was produced on a CNC turning machine to include an anatomical occlusal surface. A total of 160 epoxy resin dies were obtained by taking impressions with conventional impression methods on the metal die. Epoxy resin dies were randomly divided into four groups. Temporary crowns were prepared for each group from poly acrylic resin (Vita CADTemp®), bis-acryl composite resin (Protemp 4), poly methyl methacrylate (PMMA; Imident) and poly ethyl methacrylate (PEMA; Dentalon Plus) restorative materials. Half of the specimens (n = 20) in each group (n = 40) were randomly separated and the aging process was applied 5000 times in the device. Marginal gap measurements on epoxy resin dies were made using a stereomicroscope. The fracture strength test of the specimens was performed by using the Instron Universal Test Device. Jamovi 2.2.5 statistical program was used for statistical analysis. ResultsWhen compared to temporary crowns prepared from all other materials, poly acrylic resin (Vita CADTemp ®) temporary crowns observed significantly lower marginal gap values (59,05 μm) regardless of the aging process, and a significantly higher fracture resistance (478,44 N) in the presence of aging process (p < .05 for each). While the highest marginal gap value was detected in PMMA (Imident) (120.36 μm) temporary crowns with aging process, the lowest marginal gap value was observed in poly acrylic resin (Vita CADTemp®) (59.05 μm) crowns without non-aging process. The marginal fit and fracture resistance of all temporary crowns were negatively affected by the aging process. ConclusionOur findings revealed the superiority of poly acrylic resin (Vita CADTemp®) crowns to the temporary crowns prepared from all other materials in terms of the significantly lower marginal gap in the absence of aging process, and the significantly higher fracture resistance in the presence of aging process. Marginal fit and fracture resistance values for all materials were found to be within clinically acceptable limits.

Evaluation of the Mechanical and Adhesion Characteristics of Indirect Restorations Manufactured with Three-Dimensional Printing.

The aim of this study was to investigate the marginal fit and bond strength characteristics of onlay restorations manufactured by three-dimensional printing (Varseo XS, Bego GmbH, Bremen, Germany) and CAD/CAM (CAMcube, Montreal, QC, Canada) systems. Class II onlay cavities on sixty mandibular molars were prepared in cavities and restored in three separate groups using different fabrication methods. Digital and conventional impressions were taken to design the restorations in the CAD system (DWOS, Straumann GmbH, Freiburg, Germany). To evaluate the marginal fit and void volumes, all specimens were scanned with microcomputed tomography. A microshear test was performed to compare the bond strength of the restorations to the tooth surface. The marginal fit values measured for the 3D-printed and CAD/CAM onlay restorations were found to be at clinically acceptable levels (<120 µm), and no significant difference could be observed between the three different fabrication methods (p > 0.05). According to the microshear test results, the CAD/CAM group had the highest bond strength values before (34.82 MPa) and after (26.87 MPa) thermal cycling (p < 0.05), while the 3D-printed and conventionally produced onlays had similar results (p < 0.05). 3D printing technology is a promising option for indirect restorations; however, the post-production phase is as crucial as the printing and cementation phases.

Supply Chain Visibility and Performance of Food and Beverage Manufacturing Firms in Kenya

Purpose: The purpose of the study was to evaluate the effect of supply chain visibility on the performance of food and beverage manufacturing firms in Kenya and to find out the moderating effect of supply chain technology on the performance of food and beverage manufacturing firms in Kenya.&#x0D; Methodology: The exploratory research design was used in the study which utilized both qualitative and quantitative data. All 270 food and beverage manufacturing firms in Kenya registered by Kenya Association of Manufacturers (2022) were considered using the census approach. Target population for the research was one participant from logistics, supply chain or operations department at each of the registered food and beverage manufacturing firms. Primary and secondary data was used, the primary data was collected using semi structured questionnaire that was administered by the researcher and research assistants. Samples of the questionnaire were pilot tested to test the reliability and validity before full scale data collection. The data was analyzed using the Statistical Package for Social Sciences (SPSS) version 26 software. Quantitative data was analyzed using descriptive statistics while the inferential analysis was further carried out using structural equation modelling, ANOVA and regression coefficients to give effect of the explanatory variable.&#x0D; Findings: The study found out that supply chain visibility significantly influenced the performance of food and beverage manufacturing firms in Kenya at both when there was a moderator and without a moderating variable, supply chain technology. In the first model without moderator, it recorded a standardized estimate of 0.538 (p&lt;0.000), indicating that as supply chain visibility increases, performance of food and beverage manufacturing firms also increases. Fit indices on structural equation modelling revealed a marginal fit with a chi-square test of 211.322 with 86 degrees of freedom  (P-value =0.0492). The structural path for structural equation modelling from supply chain visibility to supply chain performance remains positive and significant. Standardized estimate of 1.347 and p-value was 0.001&lt;0.05. Which indicates that the variability of supply chain visibility on the performance of food and beverage manufacturing firms could be explained by 53.8% when no moderator is included and increased to 134.7% when ,moderator, supply chain technology is incorporated thereby indicating a stronger relationship. The other fit indices that gave a satisfactory model fit when the moderator supply chain technology was used are RMR=.9196, GFI=.9263, NFI= .9473, RMSEA=.0184 and CFI=.9369 which implies that the model was fit to determine the relationship between supply chain visibility and performance of food and beverage manufacturing firms in Kenya and therein make conclusions and recommendations. ANOVA, regression coefficient and model summary (R2) were also used and indicated significance for there use with all recording p-value of 0.000&lt;0.05.&#x0D; Unique Contribution to Theory, Practice and Policy: System theory of management was adopted and validated. By incorporating supply chain enabling technologies in the management and planning of production in a manufacturing firm, it has the potential of revolutionizing the business environment hence increasing flow of raw materials and other items into the company’s production plant, warehouses or retail locations in an effort to create visibility and enhanced performance. The theory can assist Kenya and the manufacturing firms in developing policies and strategies to assist manufacturing sector while creating competitive advantages through supply chain visibility. The study found out that some of the important supply chain mapping strategies to enhance performance of food and beverage manufacturing firms is supply chain visibility and supply chain technology.    

Supplier Collaboration and Performance of Food and Beverage Manufacturing Firms in Kenya

Purpose: This study sought to evaluate explored the influence of supplier collaboration on the performance of food and beverage manufacturing firms in Kenya and to find out the moderating effect of supply chain technology on the performance of food and beverage manufacturing firms in Kenya.&#x0D; Methodology: The study used exploratory research design and utilized both qualitative and quantitative data in carrying out the study. This study adopted a census survey sampling which was conducted on 270 food and beverage manufacturing firms in Kenya registered by Kenya Association of Manufacturers (KAM, 2022). The target population for the research was all 270 respondents each from the food and beverage manufacturing firms. Both primary and secondary data was used, the primary data was collected using semi structured questionnaire that was administered by the researcher and research assistants. Samples of the questionnaire were pilot tested to test the reliability and validity before full scale data collection. The data was analyzed using the Statistical Package for Social Sciences (SPSS) version 26 software. Quantitative data was analyzed using descriptive statistics and presented in tables and figures. The inferential analysis was further carried out using structural equation modelling, ANOVA and regression coefficients. The results were then presented using tables, figures, graphs and charts.&#x0D; Findings: Supplier collaboration significantly influenced performance of food and beverage manufacturing firms in Kenya at both without a moderator and also using the moderating variable, supply chain technology. In the first model without moderator, it recorded a standardized estimate of 0.637 (p&lt;0.001), indicating that as supplier collaboration increases performance of food and beverage manufacturing firms also increases. Fit indices on structural equation modelling revealed a marginal fit with a chi-square test of 216.155 with 86 degrees (P-value 0.0561). The structural path for structural equation modelling from supplier collaboration to supply chain performance remains positive and significant standardized estimate of 0.855 and p-value was 0.001&lt;0.05. Which indicates that the variability of supplier collaboration on the performance of food and beverage manufacturing firms could be explained by 63.7% when no moderator is included and increase to 85.5% when supply chain technology is incorporated thereby indicating a stronger relationship. The other fit indices that gave a satisfactory model fit are RMR=.9019, GFI= .9774, NFI= .9164, RMSEA=.0191 and CFI=.9176 this implies that the model was fit to determine the relationship between supplier collaboration and performance of food and beverage manufacturing firms in Kenya and therein make conclusions and recommendations. ANOVA, regression coefficient ant model summary (R2) were also used and indicated significance of there use all recording p-value of 0.000&lt;0.05. &#x0D; Unique Contribution to Theory, Practice and Policy: While transaction cost theory used in this study was validated by offering cost reduction strategies like outsourcing, accurate order forecasting as increasing the organization bottom line. The study recommends that when creating a supplier collaboration portfolio, companies should pool suppliers with the same activities in one pool but to use technology to mop up suppliers with high asset specificity for components delivering competitive advantage. Meanwhile, suppliers with low asset specificity for suppliers with components which result to less competitive advantage needs to be managed as a separate line of engagement.

Influence of glazing and aging on the marginal, axial, axio-occlusal, and occlusal fit of 3-unit monolithic zirconia restorations fabricated using additive and subtractive techniques

Studies are sparse on how glazing and aging influence the fit of additively fabricated monolithic zirconia restorations. The purpose of this in vitro study was to assess the effect of glazing and aging on the fit of 3-unit monolithic zirconia restorations fabricated using different techniques. A total of 32 monolithic zirconia restorations were fabricated for a typodont model by using 4 distinct techniques (subtractive fabrication [SF], stereolithography [SLA], digital light processing [DLP], and lithography-based ceramic manufacturing [LCM]). The silicone replica approach was adopted to measure the discrepancy values for premolar and molar abutments after sintering, glazing, and 1 year of aging. The silicone replicas were sliced into mesiodistal and buccopalatal cross-sections, and digital micrographs of the cross-sections were made with a ×80 stereomicroscope. An inherent measuring program was run to record the discrepancy values (µm). Repeated-measures 2-way ANOVAs with the Bonferroni post hoc test were used to statistically analyze the acquired data. (α=.05). From the repeated measures 2-way ANOVAs, both the glazing×fabrication technique and the aging×fabrication technique interactions were not statistically significant (P>.05). Glazing significantly influenced premolar abutment marginal (P=.022) and occlusal (P=.007) discrepancy values, as well as molar abutment marginal discrepancy values (P=.047). Aging had a statistically significant effect on premolar abutment marginal (P=.008) and occlusal (P=.011) discrepancy values, as well as molar abutment occlusal discrepancy values (P=.039). In both the glazing and aging data, for all areas of interest, statistically significant differences were detected among the fabrication techniques (P<.05). The LCM group had the lowest discrepancy values, followed by the SLA, SF, and DLP groups. The LCM and SLA groups outperformed the other groups in terms of fit accuracy. The glazing and aging procedures altered the discrepancy values. The marginal discrepancy values of all groups were below the threshold of clinical acceptability (<120µm).

Comparative evaluation of the marginal fit of computer-aided design-computer aided manufacturing fabricated crowns from direct and indirect digital impression - A systematic review.

The accuracy of the digital impression method is responsible for fabricating crowns with adequate marginal fit which in turn determines the postendodontic prognosis. This systematic review was undertaken to identify the influence of the two digital impression techniques in producing full coverage crowns with better marginal fit. This systematic review was conducted according to the Preferred Reporting Items for Systematic Review and Meta-analysis statement. A detailed search was done in electronic databases (PubMed, EBSCOhost, LILACS, Cochrane) along with hand searches of reference articles. In vivo crossover studies comparing the marginal fit of the computer-aided design-computer-aided manufacturing (CAD-CAM) fabricated crowns from direct and indirect digital impressions published from inception till July 2023 were included in this review. The quality assessment of the included articles was done based on a modified Cochrane collaboration tool for crossover studies. A total of 280 articles were identified, after duplicate removal, title and abstract screening, and full-text evaluation, 7 articles were included in this systematic review. The overall quality of evidence is moderate. The CAD-CAM crowns fabricated from direct digital impressions exhibited a better marginal fit than those crowns fabricated by indirect digital impressions. The overall quality of evidence is moderate. Further clinical studies has to be conducted for evaluating the latest technologies towards achieving the misfit of zero.

Marginal Fit and Internal Adaptation of Monolithic Zirconia 3-Unit Fixed Dental Prosthesis: In Vitro Study.

To compare the marginal and internal fit of monolithic zirconia (MZ) 3-unit fixed dental prostheses (FDPs) fabricated using two CAD/CAM workflows: full-chairside (FCH) and lab (LAB). The right maxillary first premolar and first molar were prepared for MZ 3-unit FDPs on a typodont. CEREC Primescan digitized the typodont model 15 Omes. A total of 30 FDPs was fabricated using two processes: FCH (n = 15) and LAB (n = 15). FCH and LAB FDPs were designed using CEREC SW 4.5.1 and Exocad and milled using CEREC MC X and Zirkonzhan 600/V3, respectively. A fast-sintering protocol was used in both groups. A dual-scan technique was used to assess the cement space at the occlusal surface (OC), axial wall (AX), and margin (MA). Statistical analysis of the results was performed using univariate ANOVA with Scheff. post hoc test (a = .05). Measurements in the FCH and LAB groups were within the clinically acceptable marginal and internal fit. The fit of FCH FDPs at MA, AX, and OC was 77.50 ± 29.99 μm, 99.67 ± 21.58 μm, and 150.03 ± 30.78 μm, respectively. The fit of LAB FDPs at MA, AX, and OC was 100.27 ± 27.06 μm, 116.53 ± 17.90 μm, and 142.30 ± 19.00 μm, respectively. The difference between the two groups was not statistically significant. MZ 3-unit FDPs fabricated using FCH have clinically acceptable marginal and internal fit. This result verifies the ability of FCH workflow to fabricate MZ mulOunit FDPs in a single visit.