Influence of Immediate Dentin Sealing on Bond Strength of Resin-Based CAD/CAM Restoratives to Dentin: A Systematic Review of In Vitro Studies.

Immediate dentin sealing (IDS) is a method of improving the bond strength of indirect dental restorative materials to dentin and belongs to the biomimetic protocols of contemporary dentistry. The purpose of this systematic review was to evaluate the effect of IDS on the bond strength of resin-based CAD/CAM materials to dentin. PubMed and MEDLINE, Scopus, and the Web of Science were searched by two individual researchers, namely for studies that have been published in English between 1 January 2005 and 31 December 2023 in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement. The inclusion criteria encompassed articles related to in vitro studies, measuring the bond strength through microtensile bond strength (µ-TBS), micro-shear bond strength (µ-SBS), tensile bond strength (TBS) or shear bond strength (SBS) tests after the use of the IDS technique. The included restorative materials comprised resin-based CAD/CAM materials bonded to dentin. A total of 1821 studies were identified, of which 7 met the inclusion criteria. A meta-analysis was not deemed appropriate due to the high level of diversity inthe publications and techniques. The use of IDS yielded higher bond strength outcomesin various experimental conditions and resin-based CAD/CAM materials. Overall, IDS in CAD/CAM restorations may contribute to better clinical outcomesand improved restoration longevity due to this property.

Clinical evaluation of removable partial dentures with digitally fabricated metal framework after 4 years of clinical service.

This case report describes the clinical outcomes of three patients who received removable partial dentures with a completely digitally designed and manufactured metal framework. The initial intraoral impressions were prepared, and the resulting standard tessellation language files were sent to a dental laboratory, where the alloy framework was designed using inLab software and printed using a 3D printer or milled directly from a Co-Cr disc. The quality of fit of the framework was evaluated intraorally to confirm the laboratory design. The acrylic teeth were set, and the definitive partial dentures were delivered after the acrylic resin bases were processed. The follow-up time was 4 years. No complications or failures related to the components of the partial dentures were observed.

Evaluation of repair bond strength of a dental CAD/CAM resin composite after surface treatment with two Er,Cr:YSGG laser protocols following artificial aging.

The aim of the present study was to evaluate the impact of two Er,Cr:YSGG laser surface treatments on the repair bond strength of a dental CAD/CAM resin composite (Brilliant Crios) after artificial aging. Twenty-four resin-based CAD/CAM blocks were cut and 48 rectangular slabs (3 x 12 x 14 mm) were prepared. Preliminary SEM observations indicated the most favorable laser settings regarding surface modification of the tested restorative material. The CAD/CAM specimens were then divided into 4 groups (n=12) based on their surface pretreatment: no treatment, air abraded with 50-µm Al2O3 particles, and laser irradiated with two different protocols using Er,Cr:YSGG laser with average power 3.5 and 4.5 W, pulse repetition rate 35 and 50 Hz, and pulse energy 100 and 90 mJ, respectively. After surface treatments each group followed a bonding protocol with silane and a flowable resin composite was used to prepare 48 microrods. Half of the microrods of each group were subjected on shear bond strength (SBS) test (chisel-shaped blade, load cell of 500 N, crosshead speed of 1 mm/min) after 24 h, while the other half underwent artificial aging (15,000 cycles, 5-55 °C) and then SBS test. The debonded specimens were examined under an optical microscope to determine the failure mode. All specimens were also evaluated using SEM to assess the surface topography after the treatments. The results showed that SBS significantly decreased after thermocycling in all the experimental groups (p<0.05). Control group presented much lower SBS values than the other groups after both 24 h and thermocycling (p<0.05). The highest values of SBS exhibited air-abrasion group (p<0.05), followed by the two laser groups, which did not differ to each other (p>0.05). The results of the current study indicated that Er,Cr:YSGG laser irradiation can be an alternative treatment for repairing the tested resin-based CAD/CAM restorative material.

Fracture Resistance of Class II MOD Cavities Restored by Direct and Indirect Techniques and Different Materials Combination.

This study aimed to evaluate the fracture resistance of class II MOD cavities restored using different techniques and materials. Sixty extracted maxillary molars were selected and standardized class II MOD cavities were prepared using a custom-made paralleling device. The specimens were divided into four groups based on the restoration technique used: Group 1 (direct resin composite), Group 2 (short-fiber-reinforced composite resin), Group 3 (composite polyethylene fiber reinforcement), and Group 4 (CAD/CAM resin inlays). Fracture resistance was assessed for each group after thermocycling aging for 10,000 cycles. The mode of fracture was assigned to five types using Burke's classification. To compare the fracture force among the tested materials, a paired sample t-test was performed. The significance level for each test was set at p < 0.05. Significant differences in fracture resistance were observed among the different restoration techniques. CAD/CAM inlays (2166 ± 615 N), short-fiber-reinforced composite resin (2471 ± 761 N), and composite polyethylene fiber reinforcement (1923 ± 492 N) showed superior fracture resistance compared to the group restored with direct resin composite (1242 ± 436 N). The conventional resin composite group exhibited the lowest mean fracture resistance. The choice of restoration material plays a critical role in the clinical survival of large MOD cavities. CAD/CAM inlays and fiber-reinforced composites offer improved fracture resistance, which is essential for long-term success in extensive restorations.

Evaluation of Er,Cr:YSGG laser technique for fiber post removal of endodontically treated teeth using micro-computed tomography.

Various clinical techniques such as removal kits, ultrasonic tips, burs, and drills, have been used for fiber post removal in endodontically treated teeth. In most clinical cases, the dental practitioners prefer to use ultrasonic tips, despite the heat generation and the formation of microcracks induced in the radicular dentin. The purpose of this study was to investigate the effectiveness of using erbium, chromium: yttrium-scandium-gallium-garnet (Er,Cr:YSGG) laser (2780 nm) as an alternative fiber post removal technique and to compare it to an ultrasonic method using micro-computed tomography (micro-CT). The operating parameters of the X-ray tube were set to 50 kVp and 300 mA. This approach allowed the generation of 2D lateral projections that were then used to reconstruct the 3D volume in DICOM format. Fiber posts were removed from 20 endodontically treated single-rooted premolars (n = 10) using an ultrasonic vibrator with diamond-coated ultrasonic tip (control method), or Er,Cr:YSGG laser irradiation protocol; average power 2.5 W, repetition rate 20 Hz, pulse duration 140 µs, 40% air and 20% water, and close-contact mode. The number of sections with newly formed microcracks, the loss of dentinal tissue, the amount of the residual resin cement, and the removal time were evaluated for both methods. The data were analyzed using paired t-test, Wilcoxon signed-rank and Mann-Whitney U tests at level of significance a = .05. In the laser-treated group the parameters regarding microcracks formation (21 ± 16) and removal time (4.7 ± 1.1 min) were advantageous compared to the ultrasonic-treated group (42 ± 27 and 9.2 ± 1.0 min, respectively), indicating that Er,Cr:YSGG laser could be an alternative fiber post removal technique.

Impact of erosion and aging simulation on chairside materials.

This study investigates the influence of acid exposure and thermocycling simulating erosion tooth wear, on the optical properties and surface roughness of chairside materials. Resin-ceramic, lithium disilicate, premium zirconium oxide and resin composite material comprise the materials tested. To simulate the dental erosion and aging, specimens from each material were immersed in hydrochloric acid, while the thermocycling procedure included 10,000 cycles. The translucency, the color differences and the surface roughness were calculated. The materials phase composition was tested using X-ray diffraction analysis to evaluate T-M phase transformation. The CIEDE2000 color difference and the translucency parameter were tested different significantly among groups. Data were statistically analyzed via independent samples t-test, and paired samples t-test. The thermocycling procedure and the exposure to the acid solution had different effect on the surface roughness of CAD/CAM materials. The present result demonstrated the negative effect the acid exposure has on the zirconia material in terms of color difference. However, no color differences over the threshold of acceptability were recorded after the thermocycling procedure. Both polymer materials exhibit an increase of the surface roughness when they were immersed in acid but they did not display an increase in roughness when they were thermocycled.

A Case Report of Ibandronic Acid Induced Non-Exposed BRONJ Involving the Maxillary Sinus.

Background: The aim of this case report is to present an interesting case of bisphosphonate-related osteonecrosis of the jaw, involving the maxilla and the maxillary sinus, as a result of per os administration of ibandronic acid. Methods: A female patient, 62 years old, was referred to the Department of Dentoalveolar Surgery, Surgical Implantology and Radiology, School of Dentistry, Aristotle University of Thessaloniki, Greece, complaining about pain in the first quadrant. Her medical history revealed per os bisphosphonate administration for the past four years. Subsequently, the cone-beam computed tomography examination revealed a small sequestrum of bone, surrounded by radiolucency, in proximity with the sinus floor. The clinical examination didn't reveal any pathological clinical signs. Results: Based on the radiological examination, a surgical approach was implemented to remove the necrotic bone, irrigate the alveolar process and the sinus with saline, and finally achieve primary closure, after which, the patient healed uneventfully. The osteonecrosis was attributed to the bisphosphonate administration. Conclusions: Bisphosphonate-related osteonecrosis of the jaw without obvious or with minor implication of gingival tissues is a diagnostic challenge indicating an early stage of this adverse reaction. Imaging is critical for the early detection of those cases. After careful choice of the case the proper surgical intervention could be effective to eliminate a future advancement of bone destruction. The prevention of osteonecrosis of the jaw can be achieved through the provision of adequate education to dental medicine practitioners, medical doctors, and patients.

Monomers Release from Direct and Indirect Resin-Based Restorations after Immersion in Common Beverages.

Impurities or degradation of the components of resin-based materials have been throughout investigated by the dental scientific community. The aim of this study is to examine if there is a release of monomers from resin-based materials when they are immersed in common beverage materials which are consumed by the population in large quantities. Three representative dental materials were used for this study, one resin composite indicated for direct restorations and two Computer Aided Design and Computer Aided Manufacturing (CAD/CAM) materials with different methods of fabrication. Forty specimens were fabricated from each material using a low-speed precision sectioning blade 12 × 14 × 2 mm in size and immersed in wine, coffee or cola for 48 h and 12 days, equivalent to 1 month and 1 year of consumption. The materials released more monomers when the materials were immersed in the wine solution (p < 0.05). CAD/CAM materials release less monomers compared to the resin composite material indicated for direct restorations (p < 0.05). The CAD/CAM materials leach a limited quantity of monomers when they are immersed in common beverages due to the manufacturing process which includes high-temperature/high-pressure polymerization.

Effects of milling method and artificial ageing on optical properties of high translucent zirconia for chairside restorations.

OBJECTIVES: This study aimed to evaluate the optical properties of highly translucent 5 mol% yttria, partially stabilised monolithic zirconia, and 3 mol% yttria-stabilised tetragonal zirconia after their subjection to different milling methods and artificial ageing. METHODS: Two types of pre-shaded zirconia materials were used: inCoris TZI C and Katana STML. A total of 120 specimens were categorised according to the milling method (dry or wet-milling) and the solution used for milling (fresh distilled water or impregnated water with residues of CAD/CAM ceramic materials). The translucency and contrast ratios of all specimens were calculated after they were subjected to sintering and accelerated ageing. The material phase composition was tested before and after ageing, using X-ray diffraction analysis to evaluate T-M phase transformation. Data were statistically analysed via a three-way analysis of variance between the subject factors, the material and milling method, and the within-subject factor, ageing. The analysis of covariance model was used to analyse the changes in translucency and contrast ratio between baseline and ageing, with statistical significance set at p < 0.05. RESULTS: Katana STML and inCoris TZI C showed the highest translucency when dry-milled (21.9 ± 1.4, and 11.8 ± 0.7, respectively), and the lowest when milled with used impregnated water (5.4 ± 1.2 and 10.7 ± 1.3, respectively). Wet-milling using impregnated water, should be avoided owing to the saturation of alumina particles. Accelerated ageing resulted in the same pattern for both materials. Significance Dry milling of highly translucent zirconia can result in higher translucency and lower contrast ratio values.

A fabric phase sorptive extraction method for the LC-UV determination of bisphenol A and leaching monomers from dental materials in human saliva.

A rapid and simple fabric phase sorptive extraction (FPSE) procedure is developed for the simultaneous extraction of four monomers (Bisphenol A, BPA; Triethylene glycol dimethacrylate, TEGDMA; Urethane dimethacrylate, UDMA; Bisphenol A-glycidyl methacrylate, BisGMA) in human saliva, prior to the determination by high pressure liquid chromatography with an ultraviolet-visible detector. FPSE is a green sample preparation technique, harmonized with the principles of Green Analytical Chemistry (GAC), which utilizes a flexible surface, such as cellulose, chemically coated with a polymeric material using sol-gel technology. FPSE membranes are characterized by superior chemical stability and any solvent or solvent mixture can be used for elution. Among twelve different sol-gel coated membranes, an FPSE membrane coated with sol-gel polytetrahydrofuran (sol-gel PTHF) was found optimum to extract four target compounds from saliva samples, which were first centrifuged. Parameters with most significant impact on the extraction efficiency of FPSE including elution solvent, utilization of magnetic stirring, extraction time have been comprehensively studied and optimized. The studied compounds' separation was carried out by a Perfect Sil 120 ODS-2 chromatographic column (250 mm × 4.0 mm, 5 µm), using a mobile phase constituting of acetonitrile-water 70:30 % v/v (isocratic elution). The total analysis time was 10 min. Detection was achieved by an ultraviolet-visible detector at 220 nm. The method was validated in terms of sensitivity, linearity, trueness, precision, selectivity and stability of samples. For all four compounds, the limit of detection and the limit of quantification were 0.075 ng/µL and 0.25 ng/µL, respectively. Relative recovery rates were between 90.0 and 106.7%, while RSD values were <8.1 and 12% for interday and intraday repeatability, respectively. Youden & Steiner approach was applied to study method's ruggedness and reusability of the media was tested, which enhanced the green nature of technique.

Validation of a Simple HPLC-UV Method for the Determination of Monomers Released from Dental Resin Composites in Artificial Saliva.

Bisphenol-A (BPA), bisphenol A glycerolate dimethacrylate (Bis-GMA), triethylene glycol dimethacrylate (TEGDMA), and urethane dimethacrylate (UDMA) are organic monomers that can be released from dental composites into the oral cavity. Over specific concentrations, they can act as endocrine disruptors or cause toxic effects. The purpose of this work is to develop and validate an analytical method to determine BPA, Bis-GMA, TEGDMA, and UDMA monomers released from synthetic dental resins in artificial saliva. The method was validated before its application to new hybrid ceramic materials used in computer-aided design and computer-aided manufacturing (CAD/CAM) restorations to determine the release of monomers in various time intervals (e.g., 24 h, and 7, 14, 30, and 60 days), both in methanolic solutions, as well as in artificial saliva. Chromatographic analysis was performed isocratically on a Perfect Sil Target ODS-3 analytical column (250 mm × 4.6 mm, 5 µm) with CH3CN/H2O, 58/42% v/v as mobile phase within 23 min. The developed method was validated in terms of selectivity, linearity, accuracy, and precision.

Short-term and long-term release of monomers from newly developed resin-modified ceramics and composite resin CAD-CAM blocks.

STATEMENT OF PROBLEM: Monomer leaching from restorations may affect the oral mucosa and general health; however, information on monomer leaching from chairside computer-aided design and computer-aided manufacturing (CAD-CAM) restorative materials is lacking. PURPOSE: The purpose of this in vitro study was to investigate the leaching of monomers from newly introduced resin-modified ceramics and composite resin CAD-CAM blocks that were immersed in water and ethanol for short-term and long-term incubation periods. MATERIAL AND METHODS: Ten square-shaped specimens of 5 newly introduced CAD-CAM blocks were suspended by means of a silk thread in distilled water and in 75% ethanol. After 1 day, 7 days, 30 days, and 60 days, the eluates bisphenol A (BPA), urethane dimethacrylate (UDMA), triethylene glycol dimethacrylate (TEGDMA), N, N-dimethylacrylamide (DMA), bisphenol A-glycidyl dimethacrylate (Bis-GMA), and bisphenol A ethoxylate dimethacrylate (Bis-EMA) were analyzed by means of high-performance liquid chromatography (HPLC). Additional specimens of each material, before and after immersion in the solutions, were investigated by scanning electron microscopy, and elemental analysis was performed by energy-dispersive X-ray spectrometry. RESULTS: TEGDMA and UDMA were the main monomers eluted from all the materials tested. A pattern of declining release was detected for all the monomers. Bisphenol-A was not released by any of the investigated ceramic-composite or composite resin blocks either in water or ethanol. CONCLUSIONS: CAD-CAM blocks release less monomer when they are immersed in aqueous solutions in the short-term and long-term periods than conventional resin composite materials. The amount of monomer release declined until no monomer could be detected.

Computer-aided Design and Manufacturing Crown on Primary Molars: An Innovative Case Report.

AIM: Crowns are applicable on primary teeth with extensive caries, cervical decalcification, developmental defects, interproximal caries extending beyond line angles, and following pulpotomy or pulpectomy. BACKGROUND: Until now, prefabricated crowns, i.e., stainless-steel crowns (SSCs), pre-veneered SSC, and all ceramic/porcelain/zirconia crowns have been available in a range of sizes to match the first and the second primary molar teeth. CASE DESCRIPTION: This case report illustrates a clinical use of computer-aided design and manufacturing technology (CAD/CAM) for the fabrication of a crown for a decayed primary molar using a study model as a reference. The material used was a hybrid ceramic CAD/CAM block. CONCLUSION: This approach has the advantage of the customization of the abutment tooth in contrast to the previously mentioned prefabricated options. HOW TO CITE THIS ARTICLE: Mourouzis P, Arhakis A, et al. Computer-aided Design and Manufacturing Crown on Primary Molars: An Innovative Case Report. Int J Clin Pediatr Dent 2019;12(1):76-79.

Color match of luting composites and try-in pastes: the impact on the final color of CAD/CAM lithium disilicate restorations.

AIM: Color matching of the restoration to the adjacent teeth can be difficult due to the translucency of the ceramic and the visual exposure of the polymerized resin cement through the ceramic material. The aim of this study was to identify color differences between try-in pastes and the corresponding luting resin composites. MATERIALS AND METHODS: The materials tested were Variolink Veneer, Variolink Try-In, Variolink Esthetic LC, and Variolink Esthetic Try-In. Blocks of IPS e.max CAD were bisected along the vertical axis, producing specimens of different thicknesses. The surfaces to be evaluated were finely polished with a metallographic machine using 6000 grit SiC paper. The IPS e.max CAD specimens cemented with resin cement or with the try-in pastes were superimposed on a resin composite specimen reproducing the tooth structure. Evaluation of the color differences between the try-in pastes and polymerized cements of the same shade was performed with a spectrophotometer and a visual evaluation by three observers. RESULTS: The measurements showed that for shades of Variolink Veneer and Variolink Esthetic LC resin cements and the corresponding try-in pastes there were significant color differences (ΔE > 2.23). Among the groups of different thicknesses, specimens of 0.5-mm thickness exhibited the highest ΔE values, while the specimens of 2-mm thickness exhibited the lowest. CONCLUSIONS: The present study suggests that dentists should not rely on try-in pastes for the final color evaluation because they do not perfectly match the color shade of the cement used for the final luting of ceramic restorations. The originality of this study was the interpretation of color differences utilizing both a scientific spectrophotometer and visual observation.

Effect of in-office bleaching agents on physical properties of dental composite resins.

OBJECTIVES: The physical properties of dental restorative materials have a crucial effect on the longevity of restorations and moreover on the esthetic demands of patients, but they may be compromised by bleaching treatments. The purpose of this study was to evaluate the effects of in-office bleaching agents on the physical properties of three composite resin restorative materials. METHOD AND MATERIALS: The bleaching agents used were hydrogen peroxide and carbamide peroxide at high concentrations. Specimens of each material were prepared, cured, and polished. Measurements of color difference, microhardness, and surface roughness were recorded before and after bleaching and data were examined statistically by analysis of variance (ANOVA) and Tukey HSD post-hoc test at P < .05. RESULTS: The measurements showed that hue and chroma of silorane-based composite resin altered after the bleaching procedure (P < .05). No statistically significant differences were found when testing the microhardness and surface roughness of composite resins tested (P > .05). CONCLUSION: The silorane-based composite resin tested showed some color alteration after bleaching procedures. The bleaching procedure did not alter the microhardness and the surface roughness of all composite resins tested.