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The dimensional accuracy of digitally processed inlays is often questioned because of inherent manufacturing inconsistencies associated with computer-aided design and manufacturing (CAD/CAM). This study aimed to compare the absolute marginal discrepancy (AMD), marginal gap (MG), internal gap (IG), and overall discrepancy (OD) of three-dimensional (3D) printed, milled and conventional inlays. Forty resin dies were 3D-printed from a class II mesiococclusodistal preparation on a typodont and randomly distributed into four groups of 10 each. Optical impressions were taken for three groups to fabricate CAD/CAM inlays: Group PVC, 3D printed VarseoSmile Crownplus; Group PVT, 3D printed VarseoSmile TriniQ; and Group MVE, milled using Vita Enamic. For Group CGP (control), CGP was conventionally fabricated using Gradia Plus. These inlays were stabilized on dies and subjected to cone‒beam computed tomography to measure discrepancies in mesiodistal and buccolingual sectional images. All the discrepancies differed significantly among the groups (one-way ANOVA, P > 0.05). The mean OD was significantly greater in the MVE than in the PVT and CGP; the mean AMD and MG were significantly greater in the PVC than in the PVT (Tukey test, P > 0.05). Compared with the other groups, the 3D-printed inlays, especially the VarseoSmile TriniQ, presented a closer marginal and internal fit. [ABSTRACT FROM AUTHOR]

This research focused on incorporate nanoparticles though sonification of the liquid 3D printing resin used in occlusal splints in the CAD-CAM process. It was evaluated the mechanical characteristics and cytotoxic effects of polymethylmethacrylate (PMMA) resin enhanced with graphene nanoplatelets (GNP at 0.125%, 0.250%, and 0.500% w/w) utilizing the methylthiazolyldiphenyl-tetrazolium bromide (MTT) assay. The flexural strength and modulus did not significantly change with GNP incorporation with exception of 0.500% composite, in which a reduction of ~ 50% for both properties was observed. The impact resistance showed the same trend but with a reduction of ~ 75% for 0.500% composite. In tensile strength, the unmodified PMMA sample exhibited superior resistance, which diminished progressively with higher GNP concentrations until a maximum of 20% reduction with high GNP concentration. The Shore D hardness test revealed a notable reduction at 0.125%, whereas higher concentrations (0.250% and 0.500%) led to the same results of the neat resin. All samples demonstrated favorable wettability with water. Composites with GNP concentrations of 0.125% and 0.500% were found to be cytotoxic, resulting in cell viability below 70%. Furthermore, the incorporation of graphene enhanced the hydrophilicity of the material, creating a surface barrier that inhibited bacterial proliferation. Finally, despite the promising prospects of graphene in dentistry, several challenges remain that must be overcome before these materials can achieve full commercialization for other applications as bone tissue engineering, coatings for dental implants, antibacterial functionalities, and collagen membranes. [ABSTRACT FROM AUTHOR]

Background: The additive manufacturing is one of the promising methods for fabrication of zirconia based restorations: However, studies on the marginal fit of zirconia restorations fabricated with this technique are sparse. This in vitro study was to measure and compare the marginal fit of milled and printed zirconia based crowns. Methods: Twenty-two human premolars were prepared to receive zirconia crowns. Each tooth preparation was scanned by a laboratory scanner. Digitally designed crowns were divided into two groups (n = 11) according to the method of fabrication either via 3D with a commercial 3Y-TZP slurry or a 5-axis milling machine using a multilayer zirconia blank. The marginal gaps were measured before, after cementation, and after thermomechanical accelerated aging. Kolmogorov-Smirnov and Shapiro-Wilk tests were conducted. Mann-Whitney U test was used to compare between the two techniques. Friedman's test was used to compare between marginal gap distances before, after cementation and after aging. Dunn's test was used for pair-wise comparisons when Friedman's test is significant. The significance level was set at P ≤ 0.05. Results: Marginal discrepancies between the groups showed significant variations. In comparison to milled, 3D printing demonstrated a statistically significant greater marginal gap distance before, after cementation, and after aging (P < 0.001, Effect size = 2.361), (P = 0.011, Effect size = 1.28), and (P = 0.014, Effect size = 1.234), per respective. Conclusion: Significant differences were found between the two technologies used for fabricating zirconia crowns. The least discrepancies values were found with the milling technique. [ABSTRACT FROM AUTHOR]

Aim: The surface gloss of restorative materials can be greatly impacted by abrasion from tooth brushing. This study aimed to evaluate the effect of simulated tooth brushing using regular and abrasive toothpaste on the surface gloss of glazed monolithic all-ceramic restorations. Materials and methods: In this, in vitro study, four different monolithic all-ceramic materials were used: Cerec Tessera (advanced lithium disilicate), Celtra Due (zirconia reinforced lithium silicate), Cerec Zirconia+ (Translucent Zirconia), and Cerec Blocs (Feldspathic). Eighty rectangular shaped specimens were made (20 of each material) using a low-speed diamond disc with the following dimensions (12/10/ 1 mm). The samples were polished using polishing kit & paste (DIAPOL, EVE). A glaze (Universal overglaze, Dentsply Sirona) was applied to all the samples then a toothbrushing simulator was used for 10.000 cycles using two different toothpastes. Surface gloss was assessed before and after simulated tooth brushing using glossmeter. Results: The results showed a significant reduction in the mean surface gloss of the four materials after the use of regular and abrasive toothpastes (P < 0.001). In all materials, the use of abrasive toothpaste was associated with more reduction of surface gloss (P < 0.001). Conclusion: Simulated tooth brushing and toothpaste type affect the surface gloss of glazed monolithic all-ceramic materials. Clinical significance: The surface characteristics of monolithic all-ceramic materials is affected by abrasion from toothbrushing which could impact the surface of the materials and possibly alter the glaze coating, compromising the restoration’s longevity and esthetics. This effect was greater with the use of abrasive toothpaste. [ABSTRACT FROM AUTHOR]

Objective: This in vitro study aimed to evaluate and compare the marginal fit of three‐unit implant‐supported frameworks fabricated based on conventionally hand‐waxed, milled, and three‐dimensional (3D) printed patterns. Materials and Methods: Two fixture analogs were placed in the mandibular right first premolar and first molar region of the dentiform and two prefabricated abutments were secured in the fixture analogs. Thirty three‐unit wax patterns were fabricated through conventional, milling, and 3D printing techniques (n = 10 per group). After casting, the vertical marginal gaps of two abutments for each restoration were measured by using an optical microscope on 16 points around the finish line at ×80 magnification. The data were analysed by using one‐way ANOVA and Tukey's post hoc test (α = 0.05). Results: The marginal gap was found to be significantly different among the three manufacturing methods (p < 0.001) and between each pair (p < 0.001). The 3D printing group had a significantly lower marginal gap than the milling (p < 0.001) and the conventional group (p < 0.001) in the first premolar and first molar regions and the mean of the two. The marginal gap in the milling group was significantly lower than that of the conventional group (p < 0.001) in the first premolar and first molar regions and the mean of the two. Conclusion: The marginal fit of the frameworks was the best in the 3D printing method, followed by the milling, and finally the conventional method. However, the fit accuracy in all three methods remained within the clinically acceptable range (<120 μm). [ABSTRACT FROM AUTHOR]

Purpose: The aim of this study was to compare the wear and fracture resistance of single crowns produced from newly developed 3D printer resins used to produce permanent crowns and currently used composite CAD/CAM discs, after being thermomechanically aged in a chewing simulator. Materials and methods: A total of 112 stainless steel die models simulating mandibular left first molars were produced, 8 for each group. Single crowns were produced from 3 different discs (Grandio Voco [GR], breCAM HIPC [HC], and Shofu HC [SF]) by CAD/CAM milling method and manufactured from from 4 different permanent composite resins (Nexdent C&B MFH [ND], Permanent Bridge Saremco [PB], VarseoSmile Crownplus [VSC], and Şenertek P-Crown [PC]) using the 3D printing method. Stereomicroscopy, scanning electron microscope (SEM) and Finite Element Method (FEM) analysis was performed. Data were analyzed using ANOVA, paired-t tests and Tukey's HSD test (alpha = 0.05). Results: As a result of thermomechanical aging, significant difference was found between the groups in wear and fracture resistance (P <.05). The highest wear resistance was found in the VSC group, and the lowest wear resistance in the PC group. As a result of the compression test, the highest fracture resistance was noted in the GR group and the lowest in the PC group. FEM analysis performed to validate fracture experiments showed an 87% similarity to the in-vitro data. Conclusions: The crowns in all groups produced by CAD/CAM milling and 3D printing provided acceptable in vitro wear and fracture resistance for clinical application. The wear and fracture resistance of resin-based materials should be supported by clinical studies. [ABSTRACT FROM AUTHOR]

Background: Anatomically formed healing abutments were suggested in literature to address many of the issues associated with immediate posterior implant insertion such as large extraction sockets that are extremely hard to seal without reflecting the mucoperiosteal flap, extraction sockets anatomy that are not suitable for regular healing abutment placement, and potentially high occlusal stresses when planning a temporary implant supported prothesis to improve the conditioning of supra implant tissue architecture and the emergence profile of the implant supported restorations. Purpose: To clinically evaluate the peri-implant soft tissue profile of single posterior implant retained restorations and to assess patient related outcomes of the implant restorations that were conditioned immediately by CAD-CAM socket sealing abutments (SSA) versus those conditioned by Titanium (Ti) standard healing abutments (SHA). Methods: Twenty participants received twenty-two single maxillary immediate implants after flapless minimally invasive tooth extraction and 3D guided implant placement in the posterior area (premolar and molar) and allocated randomly into two groups (n = 11), the intervention group: patients received PEEK SSA and the control group: the patients received Ti SHA. Modified Pink Esthetic Score (PES) was evaluated at 3 observation periods: Baseline T0 (immediate after implant supported crown insertion), 6 months T1 and 1 year of clinical performance T2. Patient satisfaction was assessed one week and one year after crown insertion using visual analogue scale (VAS). Results: At base line, after six as well as 12 months, SSA group showed statistically significant higher total modified PES scores than SHA group (P-value < 0.001). At the 2 clinical observation periods (baseline and after one year), SSA group showed statistically significantly higher overall satisfaction score than SHA group (P-value < 0.001). Conclusion: After one year of clinical observation period, CAD-CAM PEEK socket sealing abutments together with flapless minimally invasive tooth extraction and 3D guided implant placement provided superior outcomes compared to Ti SHA in terms of peri-implant soft tissue profile. Trial registration: This study was registered on clinicaltrials.gov with ID no. NCT05276765 on 03/03/2022. [ABSTRACT FROM AUTHOR]

There is still no consensus on whether intraoral scanning for producing full-arch implant-supported prostheses is effective. Therefore, this systematic review aimed to analyze clinical studies that evaluated intraoral scanning versus conventional impression to obtain rehabilitation of full-arch fixed prostheses and removable. Registration was carried out in the PROSPERO database (CRD: 42020152197). Searches were performed in 11 databases. Review Manager 7.2 (2024) software was used for the quantitative analysis stage (α = 0.05). Bias analysis was conducted using the ROBINS-I and ROB scales, and the certainty of the evidence was evaluated using the GRADE scale. The initial search showed 33,975 abstracts and titles, from which, after applying the inclusion/exclusion criteria, 11 clinical studies were selected. Based on the studies collected, it was observed that there was no difference in the comparison between the digital (DG) and conventional (CG) groups for the following criteria: technical and biological complication rates and marginal bone loss (p > 0.05). The analysis of clinical execution time highlights a notable advantage of the DG over the CG at both scanned patient and implant levels (p < 0.05). Nevertheless, CG achieved fewer retakes than the DG (p < 0.05), demonstrating its reliability in execution. It is concluded that the survival rates of full-arch fixed prostheses produced using intraoral scanning are comparable to those achieved with traditional impression techniques, providing a reliable option for patients. However, further clinical studies are necessary due to the variability in clinical protocols. [ABSTRACT FROM AUTHOR]

Background: Increasing demand for durable and aesthetically pleasing dental restorations, including laminates, inlays, onlays, and crowns, has led to advancements in all-ceramic systems, particularly with the development of advanced lithium disilicate materials. However, limited data on the fit accuracy and fracture resistance of these materials restricts their wider application in clinical restorative practices. Aim of the study: This in vitro study aims to compare the marginal and internal fit, assess the fracture resistance, and evaluate the failure modes of crowns fabricated from advanced and conventional lithium disilicate materials. Materials and methods: Thirty two (n = 32) crowns were fabricated and categorized into two groups based on the material used: Group (CT), where crowns were milled from CEREC Tessera (n = 16), and Group (EM), where crowns were milled from IPS e.max CAD (n = 16) using a CAD/CAM system. The marginal and internal fit were assessed digitally via a triple scan protocol. All samples were subjected to a fracture resistance test with a universal testing machine, followed by an analysis of failure modes under a stereomicroscope. Results: In the evaluation of marginal, internal and total gaps, CEREC Tessera (CT) showed slightly better fit with lower gap values compared to e.max CAD (EM). However, an independent samples t-test indicated no statistically significant differences between the two groups (p = 0.141, p = 0.471). For fracture resistance (N), the CT group demonstrated higher values than the EM group; however, the independent samples t-test indicated no statistically significant difference (p = 0.053). Additionally, the Chi-squared test with Monte Carlo correction revealed no statistically significant differences in the modes of fracture between the two groups (p = 0.484). Conclusion: Considering the limitations of this study, advanced lithium disilicate crowns demonstrated better results in terms of marginal fit, internal adaptation, and fracture resistance compared to traditional lithium disilicate crowns; however, the differences were not statistically significant. Both materials exhibited comparable fracture patterns. [ABSTRACT FROM AUTHOR]

Background/Objectives: The technical development of implant-supported fixed dental prostheses (iFDP) initially concentrated on the computer-aided manufacturing of prosthetic restorations (CAM). Advances in information technologies have shifted the focus for optimizing digital workflows to AI-based processes for design (CAD). This pre-clinical pilot trial investigated the feasibility of the automatic design of three-unit iFDPs using CAD software (Dental Manger 2021, 3Shape; DentalCAD 3.1 Rijeka, exocad GmbH). Methods: Two clinical scenarios based on a full dentition were created virtually. Physical models were produced and digitized using two intraoral scanners applying quadrant or full-arch scans (Trios3, 3Shape, Copenhagen, Denmark; and Primescan AC, Dentsply Sirona, Bensheim, Germany). For each scenario, iFDP designs were generated automatically using two laboratory software systems (Dental Manger 2021, 3Shape; DentalCAD 3.1 Rijeka, exocad GmbH), resulting in 80 STL datasets (2 scenarios × 2 scan strategies × 2 IOS systems × 5 scan repetitions × 2 software). The files were analyzed clinically for the contact schemes and pontic area. One of the automated designs for each scenario was manually post-processed and one iFDP design for each scenario was manually created by experienced dental technicians (control). The time required for all the design processes was recorded. Results: The automatic design of iFDPs without manual adjustment did not lead to clinically acceptable restorations. The time required for the automatically generated/manually adjusted iFDPs designs was not significantly different to that for the manually designed restorations. Conclusions: Current laboratory software can not automatically generate three-unit iFDPs with clinically acceptable results in terms of the interproximal and occlusal contacts and the pontic design. The automatic iFDP design process currently requires manual adjustment, which means there is no benefit in terms of the working time compared with manually created restorations. [ABSTRACT FROM AUTHOR]

Background: Additively and subtractively manufactured resin-based crowns have emerged as a new option for pediatric patients. In this study, it was aimed to test the effect of the production technique on the marginal and internal gap values of resin-based crowns for primary teeth. Methods: A total of 30 crowns were produced with additive (3D printing; DLP and SLA) and subtractive (milling) technologies (n = 10). The crowns were cemented on the resin dies. Three STL files were obtained from the scans of the die, crown, and crown cemented on the die. STL data of the die and crown were superimposed on the STL data of the crown cemented on the die, and gap volume calculations in the marginal and internal areas were performed in the software. The results were statistically analyzed with one-way ANOVA and Tukey HSD tests (α = 0.05). Results: The results showed that the production technique was significantly effective on the marginal and internal gap values. The highest marginal and internal gap value was observed in the milling group, followed by the SLA and DLP groups. Conclusion: The production technique affected the fit of the resin-based crowns for primary teeth. Compared to subtractive techniques, lower marginal and internal gap volumes were found with additive production techniques. [ABSTRACT FROM AUTHOR]

Aims: To compare the accuracy of marginal fit of CAD-CAM endocrown with two different preparation forms, i.e., endocrown with ferrule and endocrown without ferrule. Settings and Design: Various studies have opined on the impact of preparation form on the marginal fit of endocrown, but studies on the effect on the marginal fit of digitally milled endocrown with and without ferrule are sparse. Materials and Methods: Total of 30 typodont were sectioned 3 mm above the cemento-enamel junction, and central cavity was prepared to depict a severely destructed tooth. The typodonts were divided into two groups: Group 1 contained specimens for endocrown without ferrule (WoF); Group 2 contained specimens for endocrown with ferrule (WF). The typodonts were prepared based on standard preparation. The specimens were then scanned using intraoral scanner, and the stereolithography (STL) was generated. Endocrowns were designed in the Exocad software using a digital library. The STL file format is translated into millable data file format (CNC- Computer numerical control) in the inLAB MC X5 Milling machine. The marginal fit of endocrowns was then assessed in the stereomicroscope. Statistical Analysis: The data was analysed with a digital image analyser. The result was generated using a two-way ANOVA test. The significance level was set at P ≤ 0.05. Results: In the present study, the marginal fit of WoF showed a superior marginal fit than WF. A statistically significant difference was seen in the marginal fit of two endocrowns, with a higher marginal discrepancy observed in the endocrown with the ferrule. The P value for the difference in the means of the marginal gap without and with ferrule (-13.42) is zero. Maximum marginal gap of 96 micron is observed for with ferrule (WF) design at location B. Minimum marginal gap of 29 micron is observed for without ferrule (WoF) at location D. Conclusions: Endocrown without a ferrule can provide a better marginal fit and can contribute to the long-term survival of restoration. [ABSTRACT FROM AUTHOR]

Abstract Background The additive manufacturing is one of the promising methods for fabrication of zirconia based restorations: However, studies on the marginal fit of zirconia restorations fabricated with this technique are sparse. This in vitro study was to measure and compare the marginal fit of milled and printed zirconia based crowns. Methods Twenty-two human premolars were prepared to receive zirconia crowns. Each tooth preparation was scanned by a laboratory scanner. Digitally designed crowns were divided into two groups (n = 11) according to the method of fabrication either via 3D with a commercial 3Y-TZP slurry or a 5-axis milling machine using a multilayer zirconia blank. The marginal gaps were measured before, after cementation, and after thermomechanical accelerated aging. Kolmogorov-Smirnov and Shapiro-Wilk tests were conducted. Mann-Whitney U test was used to compare between the two techniques. Friedman’s test was used to compare between marginal gap distances before, after cementation and after aging. Dunn’s test was used for pair-wise comparisons when Friedman’s test is significant. The significance level was set at P ≤ 0.05. Results Marginal discrepancies between the groups showed significant variations. In comparison to milled, 3D printing demonstrated a statistically significant greater marginal gap distance before, after cementation, and after aging (P

Abstract This research focused on incorporate nanoparticles though sonification of the liquid 3D printing resin used in occlusal splints in the CAD-CAM process. It was evaluated the mechanical characteristics and cytotoxic effects of polymethylmethacrylate (PMMA) resin enhanced with graphene nanoplatelets (GNP at 0.125%, 0.250%, and 0.500% w/w) utilizing the methylthiazolyldiphenyl-tetrazolium bromide (MTT) assay. The flexural strength and modulus did not significantly change with GNP incorporation with exception of 0.500% composite, in which a reduction of ~ 50% for both properties was observed. The impact resistance showed the same trend but with a reduction of ~ 75% for 0.500% composite. In tensile strength, the unmodified PMMA sample exhibited superior resistance, which diminished progressively with higher GNP concentrations until a maximum of 20% reduction with high GNP concentration. The Shore D hardness test revealed a notable reduction at 0.125%, whereas higher concentrations (0.250% and 0.500%) led to the same results of the neat resin. All samples demonstrated favorable wettability with water. Composites with GNP concentrations of 0.125% and 0.500% were found to be cytotoxic, resulting in cell viability below 70%. Furthermore, the incorporation of graphene enhanced the hydrophilicity of the material, creating a surface barrier that inhibited bacterial proliferation. Finally, despite the promising prospects of graphene in dentistry, several challenges remain that must be overcome before these materials can achieve full commercialization for other applications as bone tissue engineering, coatings for dental implants, antibacterial functionalities, and collagen membranes.

Aims: To compare the accuracy of marginal fit of CAD-CAM endocrown with two different preparation forms, i.e., endocrown with ferrule and endocrown without ferrule. Settings and Design: Various studies have opined on the impact of preparation form on the marginal fit of endocrown, but studies on the effect on the marginal fit of digitally milled endocrown with and without ferrule are sparse. Materials and Methods: Total of 30 typodont were sectioned 3 mm above the cemento-enamel junction, and central cavity was prepared to depict a severely destructed tooth. The typodonts were divided into two groups: Group 1 contained specimens for endocrown without ferrule (WoF); Group 2 contained specimens for endocrown with ferrule (WF). The typodonts were prepared based on standard preparation. The specimens were then scanned using intraoral scanner, and the stereolithography (STL) was generated. Endocrowns were designed in the Exocad software using a digital library. The STL file format is translated into millable data file format (CNC- Computer numerical control) in the inLAB MC X5 Milling machine. The marginal fit of endocrowns was then assessed in the stereomicroscope. Statistical Analysis: The data was analysed with a digital image analyser. The result was generated using a two-way ANOVA test. The significance level was set at P ≤ 0.05. Results: In the present study, the marginal fit of WoF showed a superior marginal fit than WF. A statistically significant difference was seen in the marginal fit of two endocrowns, with a higher marginal discrepancy observed in the endocrown with the ferrule. The P value for the difference in the means of the marginal gap without and with ferrule (-13.42) is zero. Maximum marginal gap of 96 micron is observed for with ferrule (WF) design at location B. Minimum marginal gap of 29 micron is observed for without ferrule (WoF) at location D. Conclusions: Endocrown without a ferrule can provide a better marginal fit and can contribute to the long-term survival of restoration.

Abstract Purpose The aim of this study was to compare the wear and fracture resistance of single crowns produced from newly developed 3D printer resins used to produce permanent crowns and currently used composite CAD/CAM discs, after being thermomechanically aged in a chewing simulator. Materials and methods A total of 112 stainless steel die models simulating mandibular left first molars were produced, 8 for each group. Single crowns were produced from 3 different discs (Grandio Voco [GR], breCAM HIPC [HC], and Shofu HC [SF]) by CAD/CAM milling method and manufactured from from 4 different permanent composite resins (Nexdent C&B MFH [ND], Permanent Bridge Saremco [PB], VarseoSmile Crownplus [VSC], and Şenertek P-Crown [PC]) using the 3D printing method. Stereomicroscopy, scanning electron microscope (SEM) and Finite Element Method (FEM) analysis was performed. Data were analyzed using ANOVA, paired-t tests and Tukey’s HSD test (alpha = 0.05). Results As a result of thermomechanical aging, significant difference was found between the groups in wear and fracture resistance (P

Abstract Background Anatomically formed healing abutments were suggested in literature to address many of the issues associated with immediate posterior implant insertion such as large extraction sockets that are extremely hard to seal without reflecting the mucoperiosteal flap, extraction sockets anatomy that are not suitable for regular healing abutment placement, and potentially high occlusal stresses when planning a temporary implant supported prothesis to improve the conditioning of supra implant tissue architecture and the emergence profile of the implant supported restorations. Purpose To clinically evaluate the peri-implant soft tissue profile of single posterior implant retained restorations and to assess patient related outcomes of the implant restorations that were conditioned immediately by CAD-CAM socket sealing abutments (SSA) versus those conditioned by Titanium (Ti) standard healing abutments (SHA). Methods Twenty participants received twenty-two single maxillary immediate implants after flapless minimally invasive tooth extraction and 3D guided implant placement in the posterior area (premolar and molar) and allocated randomly into two groups (n = 11), the intervention group: patients received PEEK SSA and the control group: the patients received Ti SHA. Modified Pink Esthetic Score (PES) was evaluated at 3 observation periods: Baseline T0 (immediate after implant supported crown insertion), 6 months T1 and 1 year of clinical performance T2. Patient satisfaction was assessed one week and one year after crown insertion using visual analogue scale (VAS). Results At base line, after six as well as 12 months, SSA group showed statistically significant higher total modified PES scores than SHA group (P-value

Abstract Background The aim of this study was to investigate the effects of different types of bleaching methods and repolishing on the whiteness index and staining susceptibility of additive and subtractive production resin-based materials and direct composite resins. Methods In this study, a total of 96 samples (8*8*2m) were prepared using a nanohybrid composite resin (Neo SpectraTM-ST (NS)), a subtractive-manufactured nanoceramic resin (CerasmartTM270 (CS)), and an additive-manufactured permanent resin (Saremco print Crowntec (CT)). The samples were randomly divided into four treatment groups: control (distilled water, 14 days), in-office bleaching (Opalescence Boost-40% HP, 3*20min), at-home bleaching (Opalescence PF-16% CP, 6 h, 14 days), and toothpaste group (Opalescence Whitening, 2*5min, 14 days) (n:8). After each the bleaching procedure was completed, the samples were kept in coffee solution for 7 days. Following, all samples were repolished. The color of the samples was measured with a spectrophotometer at baseline (T0), after bleaching (T1), after staining in coffee (T2) and after repolishing (T3). The whiteness index change (∆WID, T1-T0), staining susceptibility (∆E1, T2-T1) and color change after repolishing (∆E2, T3-T1) of the samples were calculated in the CIE (Commission International De I’Eclairage) system. The data were analyzed by SPSS software One-Way ANOVA, post-hoc Tukey, post-hoc Tamhane’s-T2 and Paired-samples T test (α = 0.05). Results The ∆WID of all tested materials was significantly different in the in-office bleaching group compared to the control group (p

Computer-aided design-computer-aided manufacturing (CAD-CAM) systems have been widely used as a fabrication method for restorations because of their high efficiency and accuracy, which significantly reduces fabrication time. However, molars with insufficient clearance or short clinical crown lengths require retention holes or grooves on the preparation, making it difficult to replicate the shapes with the CAM milling system. In these cases, restorations using the lost-wax method are selected. This article focuses on one-piece endodontic crowns (endocrowns) fabricated with a CAD-CAM system (CAD-CAM endocrowns), in which their posts and crowns are integrated. Articles from July 2012 to August 2023 were searched in PubMed with the keyword ''endocrown''. This review discusses the application of CAD-CAM endocrowns to molars from the viewpoint of model experiment (fracture resistance, adaptation) and clinical research. This technique, which allows margins and internal gaps to be set within the clinically acceptable range, is reported to be an effective way of restoring molars with high survival rates in clinical research.

Most reports on duplicate dentures are introduction to fabrication methods or clinical case reports. Only a few studies have verified their clinical effectiveness; hence, evidence to construct useful clinical guidelines for duplicate denture use is lacking. This review aimed to comprehensively investigate reports on duplicate dentures to accumulate evidences that will contribute to the formulation of clinical practice guidelines. Duplicate dentures are effectively used for impression making and bite registration when fabricating new dentures, thereby reducing the number of clinic visits and treatment time. Duplicate denture can also be used as temporary or new dentures. Older people in whom various adaptive abilities have declined, may find it difficult to adjust to new dentures and experience stress, even if the shape is appropriate. Duplicate dentures, which reproduces the shape of old dentures that they are used to, have the advantage of being more familiar to older people and less stressful. When manufacturing duplicate dentures, digital methods such as milling and three-dimensional printing are superior to conventional methods regarding working time and cost. A notable advantage of the digital method is that the denture shape can be saved as digital data, and the denture can be easily duplicated if lost.

Background: The existing literature predominantly examines post and core assessments post-cementation, neglecting the critical pre-cementation phase. Research on the clinical acceptance of dental posts received from dental laboratories before cementation is notably lacking. This study investigates the percentage of zirconia and metal dental posts that are deemed suitable for cementation by clinicians, among the total received from the dental laboratory. Additionally, it aims to examine whether this percentage varies based on the type of impression made by the clinician: digital impression versus conventional impression. Methods: This article introduces the application of computer-aided design-computer-aided manufacturing (CAD-CAM) technology for manufacturing customized zirconia and Cobalt–Chromium (Co-Cr) post and cores. Intraoral scanning is employed to capture the canal anatomy. In contrast to the traditional casting process, a three-dimensional (3D) metal printer machine is utilized to 3D print the metal post and core from Co-Cr, resulting in enhanced toughness and superior adaptability to the canal. Two null hypotheses were formulated, investigating the clinical acceptance of zirconia and metal posts obtained through traditional versus digital impressions. Results: Among 577 post and cores, 95% of metal posts from both impression methods received clinical approval. However, for zirconia posts, a significantly higher acceptance rate (95% versus 88%) was observed for those from traditional impressions. The Chi-squared test yielded a p-value < 0.05, underscoring the clinical superiority of conventionally obtained zirconia posts and supporting the null hypothesis for metal posts. Conclusions: A significantly higher acceptance rate is apparent among zirconia post and cores manufactured through conventional impressions, in contrast to zirconia post and cores produced via digital impressions. No statistically significant difference was identified between metal post and cores obtained through digital impressions and those acquired through conventional impressions.

Abstract Background Designing the occlusal surface of a prosthesis to ensure optimal eccentric occlusion is challenging without precisely replicating the patient’s mandibular movements. During the CAD-CAM prosthesis delivery process, clinicians often need to make adjustments to the prosthesis to avoid occlusal interferences that may occur during lateral excursions. Recently, there have been developments in the field of mandibular motion tracking using optical devices. These approaches seek to incorporate an individual’s functional movement into the research field of occlusal morphology. Aim This study aimed to assess the accuracy of digitally replicating mandibular movements to identify and correct occlusal interferences in monolithic CAD-CAM zirconia crowns. Methods An intraoral scanner (IOS) was used to capture complete arch maxillary and mandibular teeth and record buccal and lateral interocclusal records of maxillary first premolar abutment teeth of thirteen participants. For each patient, two monolithic zirconia crowns were fabricated following the standard digital workflow. The crowns were categorized based on the virtual method used for adjusting occlusal interferences into two groups: Group I, where occlusal interferences in CAD-CAM zirconia crowns were adjusted using buccal interocclusal records, and Group II, where adjustments were made using both buccal and lateral interocclusal records. After crown fabrication following the manufacturer’s instructions, occlusion was analyzed using an electronic pressure analyzer. The mean, standard deviation and median values of the recorded data were measured. Paired t test and Wilcoxon Sign Rank test were executed for analyzing differences between groups (p value ≤ 0.05). Results Group I recorded higher maximum pressure at lateral mandibular movement with mean ± standard deviation value of 26.00 ± 4.95% than Group II with 20.62 ± 3.38%. Regarding pressure recorded at maximum intercuspation (MI) Group I showed higher results; 8.08 ± 1.50% compared to Group II with 7.23 ± 1.59% mean ± standard deviation value. The average value of crown volume for Group I was (160.36 ± 15.94) mm3, while for Group II was (157.63 ± 14.45) mm3. Conclusions The digital functionally generated path technique allows for identifying occlusal interferences and modifying CAD-CAM zirconia crown designs.

Abstract Background Occlusal veneer had been evaluated for mechanical properties using lithium disillicate. However, studies evaluating the mechanical properties of occlusal veneer with different preparation designs and ceramic materials are lacking. So, this in vitro study aimed to evaluate the fracture resistance of occlusal veneers with two designs fabricated from two different ceramic materials. Material and methods Fourty mandibular third molars were distributed to 2 groups (n = 20) according to preparation design: group (O) anatomical occlusal reduction and group (OA) anatomical occlusal and 1 mm axial reduction. Each group was additionally subdivided into two subgroups (n = 10) according to ceramic materials; in subgroup X, lithium disilicate (e.max CAD, Ivoclar AG, Schaan, Liechtenstein) was used, and in subgroup S, zirconia-reinforced lithium silicate (ZLS) (Vita Suprinity, VitaZahnfabrik, Bad Säckingen, Germany) was used. All specimens were cemented with a light-cure resin cement (Choice 2, Bisco, Schaumburg, USA). 5000 thermocycles were applied to all specimens with both temperatures of 5 °C and 55 °C in two water baths; the dwell time was 30s at each bath, and the transfer time was 10s. Then all specimens were subjected to a fatigue simulation under dynamic loading of 200 N for 250,000 cycles. A universal testing machine (5500R/1123, Instron, Norwood, USA) was used to evaluate the fracture strength with a crosshead speed of 1 mm/min. All data were analyzed statistically by using a two-way ANOVA, and for some violations of assumptions, these results were compared with those obtained by the nonparametric test (Scheirer Ray Hare) (α = 0.05). Results A statistically significantly higher fracture resistance in the ‘OA’ (3389 N) compared to the ‘O’ (2787 N) group regardless of the ceramic material (P

Abstract Background To evaluate the comprehensive effect of translucency, thickness, cement shades, and background color on the masking ability of resin-matrix ceramic veneer restorations. Methods Resin-matrix ceramic specimens with 2 translucencies (LT, HT) and 3 thicknesses (0.5, 1.0, and 1.5 mm) were made of Upcera Hyramic (A2 shade). Cement specimens were made of Variolink N in 4 shades (yellow, white, transparent, and bleach XL). Five background specimens were made of IPS Natural Die Material in 5 shades (ND1, ND2, ND3, ND4, and ND5). Color coordinates of 120 subgroups (n = 5) of combined specimens composed of different ceramic, cement, and background specimens were obtained using a spectroradiometer. Color difference (ΔE00) compared with a 4-mm thick specimen of LT and HT ceramics was calculated and four-way ANOVA was used for statistical analysis (α = 0.05). Results Translucency, thickness, cement shade, background color, and their interaction had significant effects on ΔE00 (p

Background: The aim of this study was to investigate the effects of different types of bleaching methods and repolishing on the whiteness index and staining susceptibility of additive and subtractive production resin-based materials and direct composite resins. Methods: In this study, a total of 96 samples (8*8*2m) were prepared using a nanohybrid composite resin (Neo SpectraTM-ST (NS)), a subtractive-manufactured nanoceramic resin (CerasmartTM270 (CS)), and an additive-manufactured permanent resin (Saremco print Crowntec (CT)). The samples were randomly divided into four treatment groups: control (distilled water, 14 days), in-office bleaching (Opalescence Boost-40% HP, 3*20min), at-home bleaching (Opalescence PF-16% CP, 6 h, 14 days), and toothpaste group (Opalescence Whitening, 2*5min, 14 days) (n:8). After each the bleaching procedure was completed, the samples were kept in coffee solution for 7 days. Following, all samples were repolished. The color of the samples was measured with a spectrophotometer at baseline (T0), after bleaching (T1), after staining in coffee (T2) and after repolishing (T3). The whiteness index change (∆WID, T1-T0), staining susceptibility (∆E1, T2-T1) and color change after repolishing (∆E2, T3-T1) of the samples were calculated in the CIE (Commission International De I'Eclairage) system. The data were analyzed by SPSS software One-Way ANOVA, post-hoc Tukey, post-hoc Tamhane's-T2 and Paired-samples T test (α = 0.05). Results: The ∆WID of all tested materials was significantly different in the in-office bleaching group compared to the control group (p < 0.05). Among the bleaching groups, the highest ∆WID was obtained in-office bleaching group of CT (2.91 ± 4.12). Staining susceptibility after bleaching (∆E1) was higher in the in-office and at-home bleaching groups compared to the control group in all tested materials. However, the difference between the treatment groups was statistically significant in NS and CS (p < 0.05). The highest ∆E1 was obtained in the in-office group of CT (7.36 ± 4.82). Color changes after repolishing (∆E2) of the tested materials were less in all groups compared to ∆E1. Conclusion: In-office and at-home bleaching can increase the whiteness index change and stain susceptibility of materials. Among the tested materials, the color stability of additive-manufactured CT was comparatively poorer. The repolishing was found to be beneficial in reducing staining. [ABSTRACT FROM AUTHOR]

ABSTRACT Objectives Materials and Methods Results Conclusion Variations in transmucosal abutment contour design may affect the outcomes of implant therapy. This randomized controlled trial was primarily aimed at testing the effect that CAD/CAM zirconia abutments with either a concave or linear divergent transmucosal morphology have on peri‐implant mucosal dynamics and indicators of peri‐implant health at 1 year after final implant‐supported prosthesis insertion in the anterior maxilla.Following computer‐guided implant placement and osseointegration, eligible subjects were randomized into either the experimental (concave morphology) or the control (linear divergent morphology) group. A comprehensive set of outcomes of interest related to peri‐implant soft tissue dynamics, phenotypical features, and indicators of peri‐implant health were assessed at different time points over a 1‐year period after insertion of the final restoration.Out of 60 initially recruited subjects, a total of 54 completed the study (n = 29 in the experimental group concave/n = 25 in the control group). Overall implant survival and restoration rates between master impression and 12 months were 100% and 98.2%, respectively. Although a trend for coronal migration of the buccal mucosa zenith, gain in mucosal thickness, and increased probing depth and bleeding on probing was observed in both groups, these changes were clinically negligible, and no substantial differences were observed between study groups regardless of variations in transmucosal abutment morphology.The use of either linear divergent or concave custom CAD/CAM zirconia abutments in a screw‐retained, delayed loading approach yielded no significant differences. [ABSTRACT FROM AUTHOR]

Purpose: The objective of this study was to assess the surface micro‐roughness and abutment adaptation of selective laser melting (SLM) implant abutments in comparison to cast and machined implant abutments. Methods: Forty abutment specimens were divided equally into four groups according to the fabrication technique as follows (n = 10), Machined Ti alloy abutments (Control), Cast CoCr abutments, SLM‐CoCr abutments, and SLM‐Ti alloy abutments. Forty internal connection implants (Ø 4.0 ×10 mm, Superline™, Dentium Co., Seoul, Korea) were mounted in clear acrylic resin. Fabricated abutments were assessed for surface micro‐roughness using a 3D optical noncontact surface microscope. Vertical and horizontal adaptation of the abutment with implant interface was assessed by using Bruker micro‐CT. Data was assessed using analysis of variance and Tukey post hoc comparison tests for all the variables except vertical misfit was assessed using Kruskal–Wallis test. Pearson correlation was used to assess dependence between independent variable (surface roughness) and dependent variables (Horizontal misfit and vertical misfit). Results: SLM‐Ti abutments showed significantly rougher surface (p < 0.05) among the study groups. While SLM‐CoCr abutments were smoother than Cast abutments with mean Ra of 1.30 ± 0.11 and 1.58 ± 0.17 μm, respectively (p < 0.05). For abutment adaptation, SLM‐Ti abutments showed the highest horizontal misfit among the groups (p < 0.05). While, SLM‐CoCr abutments (29.24 ± 11.11 μm) showed comparable (p > 0.05) horizontal misfit results with Cast (26.08 ± 3.93 μm) and machined (26.45 ± 7.33 μm) abutments. Comparable (p > 0.05) vertical misfit values between Cast CoCr (487.01 ± 40.34 μm), SLM‐CoCr (358.38 ± 114.93 μm) and SLM‐Ti (299.85 ± 172.88 μm) abutments were observed. A positive correlation was found between the surface roughness of the mating surfaces and abutment adaptation. Conclusion: SLM CoCr abutments exhibited low roughness and comparable abutment adaptation (vertically and horizontally) than cast (control) abutments. Therefore, SLM CoCr abutments should be clinically investigated as potential implant abutments for clinical use. [ABSTRACT FROM AUTHOR]

Objective: In oral rehabilitation, a full mouth minimal invasive treatment can represent a major challenge for the patient and the dentist. The purpose of this article is to present a new technique to restore eroded teeth and recover the vertical dimension with a simple and predictable technique. Clinical Considerations: Occlusal tabletop restorations are a suitable conservative option to restore anatomy and vertical dimension augmentation but highly sensitive. The cementation of those restorations without stable landmarks, the cement excess removal, the insertion path, or the time needed are some of the difficulties can be faced. Now a days with the new CAD‐CAM techniques is possible to develop a new occlusal tabletop manufacturing alternative utilizing 3D‐printed technology by unifying the restorations with a customized connector that allows us to print several onlays at same time, as a single object, also being cemented at once. Conclusions: This protocol reduces the technique sensitivity of a vertical dimension oral rehabilitation process, reduce the chair time, enhancing the patient‐comfort and delivers a unique way to restore dental lost anatomy as a definitive or temporary way with printing materials. Clinical Significance: With the advent of new CAD‐CAM 3D printing materials, which are increasingly versatile and gaining favor among clinicians, it is now possible to address complex clinical situations with greater predictability. This technology enables the development of treatment solutions that are both effective and efficient, consequently reducing clinical time for the patient. [ABSTRACT FROM AUTHOR]

Most reports on duplicate dentures are introduction to fabrication methods or clinical case reports. Only a few studies have verified their clinical effectiveness; hence, evidence to construct useful clinical guidelines for duplicate denture use is lacking. This review aimed to comprehensively investigate reports on duplicate dentures to accumulate evidences that will contribute to the formulation of clinical practice guidelines. Duplicate dentures are effectively used for impression making and bite registration when fabricating new dentures, thereby reducing the number of clinic visits and treatment time. Duplicate denture can also be used as temporary or new dentures. Older people in whom various adaptive abilities have declined, may find it difficult to adjust to new dentures and experience stress, even if the shape is appropriate. Duplicate dentures, which reproduces the shape of old dentures that they are used to, have the advantage of being more familiar to older people and less stressful. When manufacturing duplicate dentures, digital methods such as milling and three-dimensional printing are superior to conventional methods regarding working time and cost. A notable advantage of the digital method is that the denture shape can be saved as digital data, and the denture can be easily duplicated if lost. [ABSTRACT FROM AUTHOR]

Computer-aided design-computer-aided manufacturing (CAD-CAM) systems have been widely used as a fabrication method for restorations because of their high efficiency and accuracy, which significantly reduces fabrication time. However, molars with insufficient clearance or short clinical crown lengths require retention holes or grooves on the preparation, making it difficult to replicate the shapes with the CAM milling system. In these cases, restorations using the lost-wax method are selected. This article focuses on one-piece endodontic crowns (endocrowns) fabricated with a CAD-CAM system (CAD-CAM endocrowns), in which their posts and crowns are integrated. Articles from July 2012 to August 2023 were searched in PubMed with the keyword "endocrown". This review discusses the application of CAD-CAM endocrowns to molars from the viewpoint of model experiment (fracture resistance, adaptation) and clinical research. This technique, which allows margins and internal gaps to be set within the clinically acceptable range, is reported to be an effective way of restoring molars with high survival rates in clinical research. [ABSTRACT FROM AUTHOR]

Conventional complete denture wearers often complain of lack of stability and overall discomfort with their prostheses. The advent of dental implants and advanced prosthetic methods have greatly improved this struggle for edentulous patients. The utilisation of computer-aided design and computer-aided manufacturing (CAD-CAM) technology has only further enhanced the capabilities of dental practitioners to rapidly and accurately restore edentulism. This report details the advantages of using CAD-CAM technology compared to analogue methods for titanium framework design and fabrication. It discusses the decrease in framework distortions, ease of communication with laboratories, and amount of time saved from the implementation of this technology. The results of this clinical report suggest that fixed dental prostheses with titanium frameworks fabricated using the software and scanner presented in this report fit accurately and may be a viable option to restore edentulous arches. [ABSTRACT FROM AUTHOR]

Background: The existing literature predominantly examines post and core assessments post-cementation, neglecting the critical pre-cementation phase. Research on the clinical acceptance of dental posts received from dental laboratories before cementation is notably lacking. This study investigates the percentage of zirconia and metal dental posts that are deemed suitable for cementation by clinicians, among the total received from the dental laboratory. Additionally, it aims to examine whether this percentage varies based on the type of impression made by the clinician: digital impression versus conventional impression. Methods: This article introduces the application of computer-aided design-computer-aided manufacturing (CAD-CAM) technology for manufacturing customized zirconia and Cobalt–Chromium (Co-Cr) post and cores. Intraoral scanning is employed to capture the canal anatomy. In contrast to the traditional casting process, a three-dimensional (3D) metal printer machine is utilized to 3D print the metal post and core from Co-Cr, resulting in enhanced toughness and superior adaptability to the canal. Two null hypotheses were formulated, investigating the clinical acceptance of zirconia and metal posts obtained through traditional versus digital impressions. Results: Among 577 post and cores, 95% of metal posts from both impression methods received clinical approval. However, for zirconia posts, a significantly higher acceptance rate (95% versus 88%) was observed for those from traditional impressions. The Chi-squared test yielded a p-value < 0.05, underscoring the clinical superiority of conventionally obtained zirconia posts and supporting the null hypothesis for metal posts. Conclusions: A significantly higher acceptance rate is apparent among zirconia post and cores manufactured through conventional impressions, in contrast to zirconia post and cores produced via digital impressions. No statistically significant difference was identified between metal post and cores obtained through digital impressions and those acquired through conventional impressions. [ABSTRACT FROM AUTHOR]