Advances in zirconia-based dental materials: Properties, classification, applications, and future prospects.

OBJECTIVES: Zirconia (ZrO2) ceramics are widely used in dental restorations due to their superior mechanical properties, durability, and ever-improving translucency. This review aims to explore the properties, classification, applications, and recent advancements of zirconia-based dental materials, highlighting their potential to revolutionize dental restoration techniques. STUDY SELECTION, DATA AND SOURCES: The most recent literature available in scientific databases (PubMed and Web of Science) reporting advances of zirconia-based materials within the dental field is thoroughly examined and summarized, covering the major keywords "dental zirconia, classification, aesthetic, LTD, applications, manufacturing, surface treatments". CONCLUSIONS: An exhaustive overview of the properties, classifications, and applications of dental zirconia was presented, alongside an exploration of future prospects and potential advances. This review highlighted the importance of addressing challenges such as low-temperature degradation resistance and optimizing the balance between mechanical strength and translucency. Also, innovative approaches to improve the performances of zirconia as dental material was discussed. CLINICAL SIGNIFICANCE: This review provides a better understanding of zirconia-based dental biomaterials for dentists, helping them to make better choice when choosing a specific material to fabricate the restorations or to place the implant. Moreover, new generations of zirconia are still expected to make progress on key issues such as the long-term applications in dental materials while maintaining both damage resistance and aesthetic appeal, defining the directions for future research.

Applications of artificial intelligence in restorative dentistry: a scoping review.

OBJECTIVE: Artificial intelligence (AI) applications in restorative dentistry have remarkably increased in the past 5 years. This review outlines the applications, promises, and limitations of AI in the most performed procedures in restorative dentistry. METHOD AND MATERIALS: An electronic search was performed in four databases: MEDLINE/PubMed, Embase, Web of Science, and Scopus. The search included articles published in English language without date restriction. Two independent reviewers assessed the eligibility of the studies and performed data extraction. Any discrepancy was resolved by the consensus of a third reviewer. RESULTS: A total of 33 studies were included in this review. For AI applications in restorative dentistry, the included studies were classified into three main groups: (1) diagnosis, detection, and prediction of the disease, (2) detection and prediction of the longevity of dental restorations, and (3) teeth detection and treatments. For each study, the AI model, type of dataset, sample size, and main results (accuracy, precision, sensitivity, and specificity) were reported. CONCLUSIONS: AI systems are promising as advantageous aids for diagnosis, prediction, and treatment in dentistry, with a high degree of accuracy. Despite the AI promises, several limitations are still unresolved and must be addressed to bridge the gap between technology and clinical applications.

Immediate Loading of 3-Unit Posterior Fixed Dental Prostheses on 3 Vs 2 Implants, Comparison and Evaluation with up to 10-Year Follow-up.

AIMS: The aim of this prospective study was to evaluate and compare the implant survival rate, marginal bone levels and prostheses failure rate, of three-unit fixed dental prostheses (FDPs) supported by three vs. two implants immediately loaded in the posterior area. MATERIAL AND METHODS: Partially edentulous patients in need of a three-unit implant supported FDP in the maxillary/mandibular posterior region were recruited and randomly split into two groups: Group 1 with three-unit FDP supported by three implants (Control); Group 2 with three-unit FDP supported by two implants (Test). Implants were inserted and immediately loaded with a temporary FDP. RESULTS: Sixty-three patients were included in the study. A total of 178 implants were placed and immediately loaded (128 maxillary/50 mandibular) to support 74 immediate provisional fixed prostheses (52 maxillary and 22 mandibular) delivered on the same day of implant insertion/placement; 30 in Group 1 and 44 in Group 2. The comparison of three vs. two implants resulted in comparable implant survival rate, marginal bone loss, and prostheses failure rate. All implants healed uneventfully with no adverse clinical and radiographical signs or symptoms except for one implant failure in Group 1 resulting in a cumulative success rate of 99,5%, 98,9% for Group 1 and 100% for Group 2 with a follow-up of 6-to-10 (mean 7 years). Once loaded, the implants remained in function from a minimum of 6 years to 10 years. CONCLUSIONS: Although more studies and larger sample sizes are needed to validate this study, the results showed no difference between the two Groups, demonstrating the potential viability of both clinical options.

Geriatric Characterization of Older Persons with Deficient Removable Dental Prostheses

Aging is a gradual and adaptive process that entails a series of changes, leading to reduced functional and physiological capacity. Each elderly person presents heterogeneous health conditions that must be considered by the interdisciplinary team responsible for their functional maintenance and overall health. This descriptive, cross-sectional study was conducted on elderly individuals with deficient removable dental prostheses, treated at the dental prosthetic rehabilitation centre of Hospital Del Salvador, in Santiago de Chile between the years 2021 and 2023. Instruments and indices were used to record and measure muscular conditions, such as the hand grip strength measurements, the Timed Up and Go test, and the calf circumference measurement. Information on educational levels, geriatric syndromes, chronic diseases, and medication consumption was collected. Of the participants, 58.9 % were female, and 41.1 % were male, with a mean age of 84.2 years for males and 80.4 years for females. 20.8 % had access to higher education, and 22.6 % lived alone. 78.5 % had lost all posterior support zones. 81.5 % had visual impairments; 36.3 % had auditory impairments, and 31.5 % had experienced one or more falls in the last 6 months. The mean sum of medications consumed per person was 4.32. The most prevalent morbidities were arterial hypertension (66.4 %) and type II diabetes (32.7 %). Means values for male/ female were: Hand Grip Strength 27.84 Kg/17.99 kg, Timed Up and Go 14.3 sec/14.9sec, BMI 27.16/ 26.44, and calf circumference 35.5 cm /35.2cm, values were within the normal range of values. The data collected is important to consider when treatment planning and implementing actions aimed at maintaining oral and general functionality. These aspects should be addressed from a multidimensional perspective, including risk factors, in both the diagnosis and dental treatments.

Envejecer es un proceso gradual y adaptativo que conlleva cambios, que reducen la capacidad funcional y fisiológica. Cada persona mayor presenta condiciones de salud heterogéneas que deben ser consideradas por el equipo interdisciplinario a cargo de su mantención funcional y estado de salud. Estudio descriptivo, corte transversal, en personas mayores portadoras de prótesis dentales removibles deficientes, del servicio dental de rehabilitación protésica del Hospital Del Salvador de Santiago de Chile, entre los años 2021-2023. Se emplearon instrumentos e índices para realizar registro y medición de condiciones musculares como fuerza de presión manual, prueba Timed Up and Go y medición del perímetro de pantorrilla. Se recolectó información asociada a nivel de escolaridad, síndromes geriátricos, enfermedades crónicas y cantidad de fármacos que consumen. Un 58,9 % eran mujeres, la edad media de hombres fue de 84,2 años y la de mujeres fue de 80,4 años. Un 20,8 % tuvo acceso a educación superior. El 22,6 % vive solo. Un 78,5 % ha perdido todas las zonas de soporte dentario posterior. Un 81.5 % tiene alteraciones visuales; un 36.3 % alteraciones auditivas; un 31.5 % ha tenido 1 o más caídas en los últimos 6 meses. La media de fármacos fue de 4.32 por persona. Las morbilidades más prevalentes fueron hipertensión arterial (66.4 %) y diabetes tipo II (32,7 %). Los valores promedios encontrados para hombres/mujeres en fuerza de prensión manual fueron 27,84 Kg/17,99 kg, Timed Up and Go fueron 14,3 sec / 14,9 sec, IMC 27,16/ 26,44 y perímetro de pantorrilla 35,5 cm / 35,2 cm. Todos los datos clasificaron en el rango de normalidad. Las características observadas son importantes a considerar al momento de planificar tratamientos e implementar medidas orientadas a mantener funcionalidad oral y general. Éstas deben ser abordadas desde una mirada multidimensional, incluyendo los factores de riesgo, tanto en el diagnóstico como su tratamiento odontológico.

Cross-sectional analysis comparing prefabricated titanium to individualized hybrid zirconia abutments for cemented zirconia based fixed dental prostheses: a critical concept assessment.

PURPOSE: Despite the differences in material properties and shapes among the different types of prefabricated titanium (pTiA) and individualized hybrid zirconia abutments (ihZiA), the biological and clinical relevance of materials and construction features remains vague. Yet, individualized ihZiA are increasingly implemented into daily routine aiming to satisfy rising expectations. The objective was to compare these two types of abutments in fixed dental prostheses (FDP). METHODS: This cross-sectional study examined 462 implants in 102 patients comparing pTiA (52 patients) to ihZiA (50 patients) for FDP. These different treatment regimens were evaluated in terms of peri-implant health, radiographic bone loss, and oral-health related quality of life (OH-QoL) with special consideration of abutment type and superstructure design. RESULTS: ihZiA showed significantly different design features than prefabricated pTiA, but the annual bone loss in both groups did not. Visible titanium in the esthetic zone negatively impacted OHIP 14 scores. The combination of an emergence angle (EA) of < 30° and a concave emergence profile (EP) as well as gingiva thickness (p = 0.002) at the time of the prosthetic restoration significantly improved the annual peri-implant bone loss, independently of the abutment type. CONCLUSION: ihZiA showed comparable results to pTiA. To optimize the long-term outcome, not just material alone but generating adequate soft tissue thickness, minimizing the EA, and applying a concave EP seem to be the most relevant factors. To improve OH-QoL, particular attention must be paid to the esthetic zone.

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.

PURPOSE: 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. MATERIAL AND METHODS: 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, 1000 bar pressure, 2 h), and the tests were repeated (α = 0.05). RESULTS: 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. CONCLUSIONS: 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.

Evaluating the color stability of temporary crowns fabricated by 3-dimensional printing and manual methods.

This in vitro study aimed to compare the color stability of temporary crowns fabricated by 3-dimensional (3D) printing with that of crowns fabricated with 2 manual methods. An impression was made of a prepared central incisor, from which 90 dies were fabricated. The dies were randomly assigned to 3 groups (n = 30) based on crown fabrication method: 3D printing, automix bis-acryl resin, or powder-and-liquid polymethyl methacrylate. All specimens were immersed in a coffee, soft drink, or distilled water solution for 1 week (n = 10 per subgroup). Color change was measured using a spectrophotometer and the International Commission on Illumination's CIE L*a*b* method, and the values were converted to the National Bureau of Standards (NBS) index for assessment and comparison. When color change was assessed according to fabrication method, the highest (mean [SD]) ΔE* value was reported for the automix specimens (3.39 [2.86]), and the lowest was recorded for the powder-and-liquid specimens (2.05 [2.33]) (P < 0.05; Kruskal-Wallis test). The difference between ΔE* values of the 3D printing group (2.46 [1.75]) and the powder-and-liquid group was not statistically significant. When color change was assessed according to the immersion solution, the coffee solution showed a significantly higher (mean [SD]) ΔE* value (5.04 [2.67]) than the soft drink (1.43 [0.92]) and distilled water (3.41 [7.93]) solutions (P < 0.05; Kruskal-Wallis test). The color changes associated with the 3 methods were statistically equal in terms of the NBS index ranges, most frequently falling in the range of very minor to acceptable change. The powder-and-liquid method seems to be most suitable for fabricating temporary prostheses for long-term use.

Dentition status and risk of frailty in older Chinese people: a 16-year prospective cohort study.

OBJECTIVE: To explore associations of dentition status with frailty and death. METHODS: Based on the "Chinese Longitudinal Healthy Longevity Survey (CLHLS) in 2002-2018", a prospective cohort study was conducted that 21,159 participants not frail and aged ≥ 65 were included at baseline. The outcome was frailty and death. Frailty index (FI) was constructed based on 44 health items. The mediation role of high sensitivity C-reactive protein (hs-CRP) was examined using cross-sectional data in 2008, 2011 and 2014. RESULTS: The incidence density of frailty was 50.1 (95%CI: 48.8∼51.4) per 1,000 person-years. Compared with ≥ 20 natural teeth, the odds of frailty hazards were 1.27 (95%CI: 1.16∼1.39) times higher for < 20 natural teeth with dental prostheses, and were 1.24 (95%CI: 1.14∼1.35) times higher for < 20 natural teeth without dental prostheses; the odds of death hazards for < 20 natural teeth without dental prostheses were 1.36 (95%CI: 1.26∼1.45) times higher. Among participants with <20 natural teeth and without dental prostheses at baseline, the odds of frailty hazards for using dental prostheses were 0.48 (95%CI: 0.41∼0.56) times as high as those remaining not to use, and the odds of death hazards were 0.44 (95%CI: 0.39∼0.48) times as high. The cross-sectional data showed higher levels of hs-CRP explained 5∼6% of associations between dentition status and frailty. CONCLUSION: Natural teeth <20 was associated with higher odds of frailty and death. Mediation analysis based on cross-sectional data offered clues for chronic inflammation pathway, yet this finding is still needed to be further verified.

Retention of titanium copings to implant-supported fixed dental prostheses.

PURPOSE: The aim of this in vitro study was to assess the effects of using different cements and titanium copings designs on the retention of implant-supported fixed dental prostheses (IFDPs) using a pull-out test. MATERIALS AND METHODS: Fifty zirconia (ZirCAD; Ivoclar Vivadent) and 20 prepolymerized denture acrylic resin (AvaDent) rectangular (36 mm × 12 mm × 8 mm) specimens were milled to mimic the lower left segmental portion of the All-on-Four IFDPs. Cylindrical titanium copings (Variobase; Straumann) (V) were used in 2 prepolymerized denture acrylic resin groups (n = 10) while conical titanium copings (Straumann) (C) were used as a control group for zirconia with 4 groups using cylindrical titanium copings. Before cementation, the outer surfaces of all titanium copings and the intaglio bonding surface of prosthetic specimens were airborne-particle abraded. All specimens were cemented following the manufacturer's recommendations and instructions according to the experimental design. After artificial aging (5000 cycles of 5°C 55°C, dwelling time 20 s; 150 N, 1.5 Hz in a 37°C water bath), all specimens were subjected to retention force testing using a pull-out test using a universal testing machine and a custom fixture with a crosshead speed 5 mm/min. Modes of failure were classified as Type 1, 2, or 3. Retention force values were analyzed by the t-test for the prepolymerized denture acrylic resin specimen groups, and 1-way ANOVA and the Tukey test for the zirconia groups at α = 0.05. RESULTS: Mean and standard deviation retention force values varied from 101.1 ± 67.1 to 509.0 ± 65.2 N for the prepolymerized denture acrylic resin specimen groups. The zirconia groups ranged from 572.8 ± 274.7 to 1416.1 ± 258.0 N. There is no statistically significant difference in retention force values between V and C specimens cementing to zirconia with Panavia SA cement (Kuraray Noritake) (p = 0.587). The retention forces and failure modes were influenced by the cement used (p < 0.05). Modes of failure were predominantly Type 2 (mixed failure) and Type 1 (adhesive fracture from prosthetic materials) except for the quick-set resin group (Type 3, adhesive failure from coping). CONCLUSIONS: When bonding IFDPs onto titanium copings, quick-set resin provided significantly higher retention force for prepolymerized denture acrylic resin prostheses. Conical and cylindrical titanium copings performed similarly when cemented to zirconia with Panavia SA cement under the same protocol. The stability of the bonded interface and retention forces between zirconia prostheses and titanium copings varied from the cement used.

Effect of repair and surface treatments on the strength of digitally fabricated resin-based dental prostheses: A systematic review of in vitro studies.

OBJECTIVE: This review investigated the current literature pertaining to the repairability of computer-aided design-computer-aided manufacturing (CAD-CAM) milled and three-dimensional (3D) printed resin-based dental prostheses (RBDPs) as well as the appropriate surface treatment for each repair material that will produce adequate repair bond strength. DATA/SOURCES: PubMed, Web of Science, and Scopus databases were searched for published articles involving repair of CAD-CAM RBDPs between January 2010 and June 2023. Data were collected and analyzed to reveal the surface treatment effects, suggested repair materials, and strength of repaired RBDPs. STUDY SELECTION: Out of 164 retrieved titles, 11 studies were included, of which five investigated the repair of 3D-printed RBDPs, three investigated the repair of CAD-CAM milled resins, and three investigated both materials. Additionally, of the included studies, seven investigated denture base resins, three studied provisional restoration resins, and one evaluated 3D-printed intraoral splints. Various surface treatments were suggested, with air-abrasive methods being the most commonly used. Different materials for resin repair were proposed and used, including auto-polymerized, reline, and composite resins. For 3D-printed resins, repair with Bis-acrylic/Bis-GMA composites improved repair strength. CONCLUSION: Surface treatments positively affected the repair strength of conventional and milled RBDPs. However, challenges remain relevant to the repair of 3D-printed resins owing to composition mismatches and fabrication techniques. Therefore, further investigation is required to develop new 3D-printed resins. CLINICAL SIGNIFICANCE: CAD-CAM milled resins have satisfactory repair strength, which increases with surface treatment. The repair of 3D-printed resins has proven challenging even with surface treatments. However, composite resins are the materials of choice.

A Narrative Review on Polycrystalline Ceramics for Dental Applications and Proposed Update of a Classification System.

Dental zirconias have been broadly utilized in dentistry due to their high mechanical properties and biocompatibility. Although initially introduced in dentistry as an infrastructure material, the high rate of technical complications related to veneered porcelain has led to significant efforts to improve the optical properties of dental zirconias, allowing for its monolithic indication. Modifications in the composition, processing methods/parameters, and the increase in the yttrium content and cubic phase have been presented as viable options to improve zirconias' translucency. However, concerns regarding the hydrothermal stability of partially stabilized zirconia and the trade-off observed between optical and mechanical properties resulting from the increased cubic content remain issues of concern. While the significant developments in polycrystalline ceramics have led to a wide diversity of zirconia materials with different compositions, properties, and clinical indications, the implementation of strong, esthetic, and sufficiently stable materials for long-span fixed dental prostheses has not been completely achieved. Alternatives, including advanced polycrystalline composites, functionally graded structures, and nanosized zirconia, have been proposed as promising pathways to obtain high-strength, hydrothermally stable biomaterials. Considering the evolution of zirconia ceramics in dentistry, this manuscript aims to present a critical perspective as well as an update to previous classifications of dental restorative ceramics, focusing on polycrystalline ceramics, their properties, indications, and performance.

A pattern of peri-implantitis affecting middle implants in 3-implant splinted prostheses.

BACKGROUND: Previous investigators have noted an increased risk of crestal bone loss and failure of the middle implant of 3-implant-splinted (3-IS) fixed dental prostheses (FDPs). Possible causes have included ill-fitting prostheses, unhygienic prosthetic contours, and discrepancies in prosthetic platform heights. METHODS & RESULTS: We identified four cases in which the middle implant of a 3-IS multiunit FDP suffered advanced bone loss, ultimately leading to implant removal. While more than one possible risk for implant failure existed in each case, a common thread was that the prosthetic platform of the middle implant for all patients was coronally positioned relative to the corresponding mesial and/or distal implants. CONCLUSIONS: Splinting three adjacent implants into one prosthesis may add risk for a variety of reasons possibly including small differences in the heights of the three prosthetic tables. KEY POINTS: Why are these cases new information? Our observations suggest that discrepancies between implant prosthetic platforms supporting 3-implant splinted, multiunit FDPs may be an added risk factor for middle implant failure. What are the keys to successful management of these cases? It is possible that small differences in apico-coronal implant positioning with 3-implant splinted multiunit FDPs may affect the success of the middle implants. What are the primary limitations to success in these cases? There is limited literature involving precise protocols and long-term outcomes of 3-implant splinted implant restorations. Studies comparing 3-implant splinted FDPs to other configurations are needed.

The Impact of Implant Angulation on the Stress Distribution and Survival Rate of Implant-Supported Fixed Dental Prostheses: A Retrospective Study.

Background Implant-supported fixed dental prostheses (FDPs) have become a reliable method for the rehabilitation of edentulous patients, offering improved contour, function, esthetics, and overall oral health. This retrospective study aimed to evaluate the impact of implant angulation on the stress distribution and survival rate of implant-supported FDPs using finite element analysis (FEA). Methods A retrospective cross-sectional design was employed, utilizing existing patient records and radiographic data. The study followed the Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) guidelines for transparent and comprehensive reporting. Sample size calculation was based on a reference study, considering a standard deviation of 2.5 for stress distribution measurements and a minimum detectable effect size of 1.0. Data collection included demographic and clinical characteristics, implant selection and placement details, prosthetic design and fabrication, as well as stress distribution analysis using FEA. Results The study included a total of 307 participants who met the inclusion criteria. Demographic variables demonstrated a balanced gender distribution (p = 0.172), with 51.5% males and 48.5% females. Smoking status (p < 0.001) and income level (p = 0.026) were significantly associated with the research outcomes. Implant characteristics analysis revealed three main types: NobelReplace Select (53.6%), Straumann Bone Level (31.9%), and BioHorizons Tapered Internal (14.5%). Implant type (p < 0.001), length (p = 0.003), diameter (p = 0.019), and manufacturer (p < 0.001) were all found to have statistically significant associations with the research outcomes. Conclusion The findings of this retrospective study highlight the importance of implant angulation on the stress distribution and survival rate of implant-supported FDPs. The evaluation of stress distribution patterns and the analysis of implant characteristics provide valuable insights for optimizing implant design and placement strategies.

Digital measurement method for comparing the absolute marginal discrepancy of three-unit ceramic fixed dental prostheses fabricated using conventional and digital technologies.

BACKGROUND: In clinical practice, control of the marginal fit of fixed dental prostheses is hindered by evaluation method, which needs to be further improved to increase its clinical applicability. This study aimed to quantitatively analyze the absolute marginal discrepancy of three-unit ceramic fixed dental prostheses fabricated by conventional and digital technologies using a digital measurement method based on the digital impression technology and open source software. METHODS: A digital workflow and the conventional impression combined with the lost-wax heat-pressed technique were adopted to separately fabricate 10 glass ceramic fixed dental prostheses. Three-dimensional data for the abutments, fixed dental prostheses, and fixed dental prostheses seated on the abutments, were obtained using a dental scanner. The two datasets were aligned using registration technology, specifically "multi-points registration" and "best fit alignment," by reverse engineering software. Subsequently, the three-dimensional seated fit between the fixed dental prostheses and abutments were reconstructed. The margin of the abutment and crown was extracted using edge-sharpening and other functional modules, and the absolute marginal discrepancy was measured by the distance between the margin of the abutment and crown. One-way analysis of variance was used to statistically analyze the measurement results. RESULTS: Using the digital measurement method, the mean value of absolute marginal discrepancy for fixed dental prostheses fabricated by the conventional method was 106.69 ± 6.46 µm, and that fabricated by the digital workflow was 102.55 ± 6.96 µm. The difference in the absolute marginal discrepancy of three-unit all-ceramic fixed dental prostheses fabricated using the two methods was not statistically significant (p > 0.05). CONCLUSIONS: The digital measurement method for absolute marginal discrepancy was preliminarily established based on open source software and applied in three-unit ceramic fixed dental prostheses. The absolute marginal discrepancy of three-unit ceramic fixed dental prostheses fabricated using digital technology was comparable to that of conventional technique.

A Study to Evaluate the Effect of Cleaning Solutions on Shear Bond Strength of Resin Cement to Saliva-Contaminated Lithium Disilicate (LDS) Ceramic.

BACKGROUND: One of the greatest benefits of contemporary restorative dentistry is the creation of fixed partial dentures. The retention and durability of the fixed partial dentures may be improved by using a variety of tooth preparation methods, surface treatments, and luting resins. AIM: To measure the shear binding strength of resin cement to saliva-contaminated lithium disilicate (LDS) ceramic after being exposed to various cleaning treatments. METHODOLOGY: Over 30 LDS samples were examined. In Group 1, a cleansing solution comprising 15% zirconium oxide (Ivoclean) was employed for a duration of 20 s. This was succeeded by a rinsing phase lasting 15 s utilizing deionized water, followed by a 15-s period for drying. Subsequently, a final stage of air drying was conducted over a span of 15 s. In contrast, Group 2 underwent a washing procedure of 20 s involving a cleansing solution containing 30% sodium silicate. This was then ensued by a rinsing interval of 15 s with deionized water, succeeded by an air-drying process spanning 15 s. After applying cleaning solutions to the surface and adhering the specimens to the composite blocks using resin cement Multilink Automix (Ivoclar Vivadent, Schaan, Liechtenstein), the shear bond strength was assessed. RESULTS: Using a 30% sodium silicate solution (Group 2), we were able to get the highest mean shear bond strength value after saliva-contaminated LDS. Group 1, 15% zirconium oxide (Ivoclean) had the weakest decontamination agents as measured by mean shear bond strengths. The shear bond strength values of the two groups were found to vary significantly between individuals using the independent sample t-test. LDs ceramic cleaned with a 30% sodium silicate solution had a higher shear bond strength than ceramic cleaned with Ivoclean (p<0.05). CONCLUSION: The application of a 30% sodium silicate solution rendered the highest shear bond strength for saliva-contaminated LDS ceramic. In comparison, ceramic cleaned with Ivoclean exhibited notably lower shear bond strength values. The outcome of this investigation highlights the potential of diverse cleaning agents in influencing the adhesive qualities of resin cement, thereby contributing to the enhancement of fixed partial denture durability and efficacy.

Full-arch restoration with the NEXUS IOS® system: A retrospective clinical evaluation of 37 restorations after a one year of follow-up.

OBJECTIVES: Report the results with a novel workflow of digital restoration for completely edentulous patients with implant supported full arch fixed dental prostheses (ISFDP). METHODS: This multicenter retrospective clinical study was based on the evaluation from a cohort of 29 patients restored with 37 ISFDP designed and manufactured from the data captured by a direct intraoral scan, using a novel full digital system (NEXUS IOS®, Osteon Medical, a Keystone Dental Group company, Melbourne, Australia). Data was collected over a 3-year period, in six different dental centers. This study reported on the clinical parameters including: precision of marginal fit, functional and aesthetic integration of Nexus ISFDP. All patients were followed for a period of one year post delivery. Implant survival, biologic and prosthetic complications were assessed, at one year. A statistical analysis was conducted. RESULTS: All 37 ISFDP were deemed clinically acceptable on insertion. Implant survival at one year was 100 %. The biologic and prosthetic complications were minimal during the follow-up period. CONCLUSIONS: ISFDP, designed and manufactured using the NEXUS IOS® system, are clinically acceptable, with a low incidence of complications at one year. Long-term clinical studies are needed. STATEMENT OF CLINICAL RELEVANCE: Within the limitations of this study (retrospective design, small patient sample, limited follow-up) the NEXUS IOS® system seems to represent a viable solution for the restoration of completely edentulous patients with ISFDP, in a full digital workflow.

Four single implant-supported crowns replacing the maxillary incisors: A retrospective report of 10 cases with 2-9 years of follow-up.

OBJECTIVE: This retrospective case series aimed to assess the stability of the papilla around four single crowns supported by narrow-diameter implants replacing all maxillary incisors. Secondary objectives included assessment of marginal bone level stability, incidence of technical and biological complications, and patient satisfaction. MATERIALS AND METHODS: Individuals with four adjacent implants in maxillary incisor sites, placed with a 3 mm inter-implant distance and rehabilitated with single crowns were included. Retrospective data were obtained from photographs and radiographs taken at the delivery of the prosthesis (baseline-T0). Patients were then recalled (≥2 years after T0) for clinical and radiographic examination (follow-up-T1). Photographs were obtained and patient satisfaction was assessed using a visual analogue scale. Papilla height and marginal bone level were compared over time. RESULTS: Data from 10 patients with medium-low smile lines and rehabilitated with 40 implants, in function for 5.4 ± 1.9 years, were analyzed. The papilla height between implants (T0: 2.3 ± 0.9 mm; T1: 2.6 ± 0.7 mm; p = .011) and between tooth and implant (T0: 3.4 ± 0.9 mm; T1: 3.8 ± 0.8 mm; p = .025) increased significantly over the years. The marginal bone level remained stable over time (T0: 0.88 ± 0.57 mm; T1: 0.71 ± 0.67 mm; p = .007). Patients were highly satisfied (97.7 ± 0.3%) with the treatment outcome. CONCLUSION: Within its limitations, this study demonstrated that four single implant-supported crowns placed at maxillary incisor sites may exhibit soft tissue and marginal bone stability over a long period of time. This treatment approach, however, should be restricted to few patients as it requires a proper case selection and skillful execution of all surgical and prosthetic steps.

Mechanical and Surface Characteristics of Selective Laser Melting-Manufactured Dental Prostheses in Different Processing Stages.

Due to the expansion of the use of powder bed fusion metal additive technologies in the medical field, especially for the realization of dental prostheses, in this paper, the authors propose a comparative experimental study of the mechanical characteristics and the state of their microscale surfaces. The comparison was made from material considerations starting from two dental alloys commonly used to realize dental prostheses: Ni-Cr and Co-Cr, but also technologies for obtaining selective laser melting (SLM) and conventional casting. In addition, to compare the performances with the classical casting technology, for the dental prostheses obtained through SLM, the post-processing stage in which they are in a preliminary finishing and polished state was considered. Therefore, for the determination of important mechanical characteristics and the comparative study of dental prostheses, the indentation test was used, after which the hardness, penetration depths (maximum, permanent, and contact depth), contact stiffness, and contact surface were established, and for the determination of the microtopography of the surfaces, atomic force microscopy (AFM) was used, obtaining the local areal roughness parameters at the miniaturized scale-surface average roughness, root-mean-square roughness (RMS), and peak-to-peak values. Following the research carried out, several interesting conclusions were drawn, and the superiority of the SLM technology over the classic casting method for the production of dental prostheses in terms of some mechanical properties was highlighted. At the same time, the degree of finishing of dental prostheses made by SLM has a significant impact on the mechanical characteristics and especially the local roughness parameters on a miniaturized scale, and if we consider the same degree of finishing, no major differences are observed in the roughness parameters of the surfaces of the prostheses produced by different technologies.

Oral function in completely edentulous patients rehabilitated with implant-supported dental prostheses: A systematic review and meta-analysis.

OBJECTIVES: This review evaluated the effects of rehabilitation with implant-supported prostheses on the oral function of completely edentulous adults. MATERIALS AND METHODS: Systematic literature searches were performed to identify records reporting on oral function in completely edentulous adults rehabilitated with implant-supported prostheses. Meta-analyses were performed on various outcomes including bite force, masticatory performance, muscle activity, mandibular movement/chewing pattern, and salivary flow. RESULTS: 5507 records were identified. Thirty studies qualified for data extraction and analysis. The kappa (𝛋) for the search and identification strategy ranged between 0.50 and 1.00. Meta-analysis was performed grouping the studies by outcomes and split by time points of 6-12 months, 12-36 months, and >36 months after implant therapy. The meta-analyses revealed a significant improvement in oral function of completely edentulous adults after rehabilitation with implant-supported prostheses at 6-12 months (Z = -4.895, p < .001; 95% CI: -0.703, -0.301; τ2 = .609; Q = 114.953, df = 17, p < .001; I2 = 85.2%), at 12-36 months (Z = -4.886, p < .001; 95% CI: -0.580, -0.248; τ2 = .908; Q = 280.611, df = 35, p < .001; I2 = 87.5%) and at more than 36 months (Z = -9.108, p < .001; 95% CI: -1.472, -0.951; τ2 = .019; Q = 7.918, df = 7, p = .340; I2 = 11.6%). The included studies demonstrated a low to moderate risk of bias. CONCLUSIONS: This systematic review concluded that the oral function of completely edentate adults significantly improved with implant-supported/retained prostheses, even when only one jaw received implant therapy. Therefore, implant therapy should be promoted for edentulous adults to alleviate the shortcomings of conventional complete removable dental prostheses.

Clinical and radiographic outcomes of implant-supported zirconia fixed dental prostheses with cantilever extension: A proof-of-principle study with a follow-up of at least 1 year.

OBJECTIVES: To test the reliability of full zirconia implant-supported fixed dental prostheses with cantilever extension (FDPCs) after at least 1 year of function. MATERIALS AND METHODS: Thirty-five patients in need of implant-supported single unit crowns (SUC) and FDPCs in posterior areas were enrolled. After implant placement, patients were rehabilitated with screw-retained full-zirconia FDPCs. Implant survival rate, pocket probing depth (PPD), presence/absence of bleeding on probing (BoP), and presence/absence of mechanical/technical complications were recorded. Mesial and distal radiographic marginal bone levels (mBLs) from baseline (i.e., recall appointment 3-6 months after implant loading [T0]) to the follow-up examination (i.e., latest recall appointment after at least 12 months after T0 [T1]), were calculated. RESULTS: Thirty patients with 34 FDPCs (31 SUCs and 3 FDPs) supported by 37 implants were available for analysis after a mean loading time of 2.6 ± 1.5 years (range: 13-87 months). No implants were lost. MBLs and mean PPD values did not change statistically significantly from T0 to T1 from 0.92 mm ± 0.42 to 0.96 mm ± 0.38 (95% CI: -0.07/0.17; p = .418) and from 2.99 mm ± 0.70 to 3.27 mm ± 0.71 (95% CI: -0.11/0.68; p = .25) respectively. Peri-implant mucositis was diagnosed in 22 cases. Screw-loosening and zirconia chipping occurred 1× in 4 patients. CONCLUSION: Within the limitations of the present proof-of-principle study, the use of full-zirconia FDPCs in posterior areas seems a valid and safe short-term treatment option.