Purpose: The aim of the present study was to investigate the influence of three post-and-core systems and two crown materials on stresses in restored premolars using Finite Element Analysis (FEA). Materials and Methods: A maxillary second premolar 3D model was created in SolidWorks 2014 (Dassault Systémés). Severe loss of tooth structure was simulated with six restorative options: 1) glass-fiber-reinforced composite post and composite core (GFRC)+CAD/CAM leucite-reinforced glass-ceramic crown (LRC); 2) carbon-fiberreinforced composite post and composite core (CFRC)+LRC; 3) metal cast post-and-core (MPC)+LRC 4) GFRC+CAD/CAM composite resin crown (CC); 5) CFRC+CC; 6) MPC+CC. Three-point occlusal loading (150N) was simulated and von Misses and maximum principal stresses calculated. Results: Although maximum von Mises stresses in the crown and dentin were similar across groups (137.9-139.2MPa crown; 17.2-19.6 dentin), there were important differences in stress distribution in dentin. Only in MPC+CC group the maximum stresses were on the bottom of the post preparation cavity. Stress values within the posts were: CFRC(4.8MPa)>GFRC(6.7MPa)>MPC(10.3MPa). CC-restored models presented higher von Mises stresses within the post-and-core compared to the LRC groups. Maximum principal stresses were lower compared to von Mises stresses, following the same trend, and were distributed similarly in all the groups. Conclusions: Both GFRC and CFRC showed favourable stresses distribution in the dentin and restorative materials, while MPC increased stresses in core, post and post cement. The more rigid crown material seems to transmit less stresses to the underlying core and crown cement compared to CC. Keywords: cast post-and-core; fiber-reinforced composite post; composite crown; ceramic crown; finite element analysis

Purpose: To evaluate the effect of different lithium-disilicate (LiSi) glass-ceramic surface decontamination procedures on the shear bond strength (SBS) to resin cement. Materials and Methods: Seventy CAD/CAM LiSi ceramic specimens (IPS e.max CAD, Ivoclar) were cut and sintered. Fifty specimens were treated with 5% hydrofluoric acid (HF) for 20 s, while 20 were left untreated. All 70 specimens were then contaminated with human saliva and try-in silicone paste. The following surface cleaning methods were investigated (n = 10): C: water rinsing (control); PA: 37% H3PO4 etching for 20 s; E: 70% ethanol applied for 20 s; CP: cleaning paste (Ivoclean, Ivoclar) brushed for 20 s; HFSEP: self-etching ceramic primer (Monobond Etch&Prime, Ivoclar) rubbed for 20 s; HF: 5% HF applied for 20 s or no HF etching prior to contamination; SEP: self-etching ceramic primer rubbed for 20 s and no HF etching prior to contamination. Composite cylinders were created and luted with an adhesive resin cement to the decontaminated surfaces. After storage for 24 h at 37°C, the SBS test was conducted. Two fractured specimens per group were observed under SEM to perform fractographic analysis. The data were statistically analyzed with p set at <0.05. Results: The type of surface cleaning approach influenced bond strength (p < 0.001). HFSEP, SEP, and HF attained higher SBS (p < 0.001) compared to other groups. None of the approaches were able to completely remove contaminants from the ceramic surfaces. SEM images showed residual traces of contaminants on CP-treated surfaces. Conclusions: The self-etching ceramic primer enhanced bond strength to contaminated LiSi ceramic surfaces, irrespective of previous treatment with hydrofluoric acid. Keywords: lithium-disilicate glass-ceramic, surface cleaning, decontamination, hydrofluoric acid, ceramic primer, shear bond strength

Purpose: To evaluate the accuracy, working time, and patient satisfaction of digital impressions (DI) vs conventional impressions (CI) taken for removable prostheses on edentulous arches. Materials and Methods: A systematic search of the literature was conducted in electronic databases. The English language was filtered with no limitation on publication date. The search was performed up to June 2022. Only in vivo studies comparing DI and CI techniques for the fabrication of complete removable prostheses were included. The primary outcome was accuracy (in terms of trueness and precision), working time (scanning time), and patient satisfaction of DI procedures. Results: After title and abstract screening, six articles were considered eligible for inclusion. All articles investigated the trueness of DI, while no study evaluated the accuracy in terms of precision. The discrepancies between DI and CI were primarily in the peripheral areas. Only one article focused on the working time for scanning procedures. Patient satisfaction was surveyed in just one study. Lack of standardization of the CI procedures and sample size collection were observed in all studies. Conclusions: The scientific evidence so far collected on IOS for complete edentulous arches is not exhaustive, in particular when dealing with scanning time and patient satisfaction. Regarding accuracy, digital scanning in edentulous patients seems to be a predictable procedure within the limits of the attached mucosa.

Purpose: To evaluate push-out bond strength (PBS) and interfacial nanoleakage (NL) of adhesively luted fiber posts using different composite cements and polymerization protocols. Material and Methods: 100 premolars were endodontically treated and assigned to the following groups (n=10): RelyX Universal light-cure (3M Oral Care); RelyX Universal self-cure (3M Oral Care); Maxcem Elite Chroma light-cure (Kerr); Maxcem Elite Chroma self-cure (Kerr); Calibra Universal light-cure (Dentsply Sirona); Calibra Universal self-cure (Dentsply Sirona); Multilink Automix light cure (Ivoclar Vivadent); Multilink Automix self-cure (Ivoclar Vivadent); Luxacore Z Dual light-cure (DMG); Luxacore Z Dual self-cure (DMG). Half of the teeth from each group were subjected to the PBS test after 24 h (T0), while the other half was tested after 12 months (T12) of artificial saliva aging. An additional 4 teeth per group were prepared for NL expression. PBS values were analyzed using multivariate ANOVA and Tukey’s post-hoc test. NL scores were analyzed using chi-squared tests (α = 0.05). Results: Statistical analysis revealed that the variables “cement” and “aging” significantly influenced PBS (p < 0.05), but not “polymerization” and “root region” (p > 0.05). Significantly lower PBS values (p < 0.05) were detected for the Calibra Universal groups compared to other cements, while the RelyX Universal groups performed equally well (p > 0.05) or better than other cements (p < 0.05). At T12, PBS values increased in the majority of groups, irrespective of root region (p < 0.05). Differences in NL expression were present at T0, and in general, the aging process increased marginal infiltration. Conclusion: Aging and choice of composite cement influenced PBS, while root region and polymerization protocol seemed to have no influence on posts’ resistance to dislodgment. Keywords: aging, bonding, fiber post, polymerization, composite cement

Purpose: To evaluate the effect of different pretreatment protocols and adhesives on the shear bond strength and surface morphology of aprismatic enamel. Materials and Methods: Human maxillary incisors (N = 120) were assigned to five different groups according to pretreatment: 1) no treatment; 2) glycine; 3) sodium bicarbonate; 4) Al₂O₃ and 5) extra-fine bur. Then the teeth were divided into three subgroups, according to the adhesive applied: 3-step etch-and-rinse (ER), universal adhesive in ER mode, and universal adhesive in self-etch (SE) mode. Shear bond strength (SBS) testing was performed with a universal testing machine. For SEM observation, fifteen human molars were collected and analyzed after pretreatment with/without etching with 37% H₃PO₄ for 30s. Results: Al₂O₃ showed higher SBS than all other groups considered. Comparable SBS values were obtained for other pretreatments. Universal adhesive in E&R mode performed better than did 3-step E&R and universal adhesive in SE mode. SEM images showed visible differences in enamel surface roughness. Conclusions: Airborne-particle abrasion with Al₂O₃ followed by etching with H₃PO₄ increased SBS on aprismatic enamel. The combination of airborne-particle abrasion with alumina powder followed by 15 s of H₃PO₄ etching and application of a universal adhesive in E&R mode proved to be the most effective adhesive protocol. Keywords: aprismatic enamel, adhesion, no-prep restorations, airborne-particle abrasion, polishing powders

This study aimed to histologically analyze the bony tissue formed around dental implants after osseointegration. A 58-year-old patient presented with pain and discomfort caused by two dental implants in her maxilla placed 8 months earlier. At clinical and radiographic analysis, the implants appeared well osseointegrated but tilted buccally, emerging in nonkeratinized mucosa. For this reason, the discomfort began right after the prosthetic load, 4 months after implant placement, and the patient felt pain when wearing the implant-supported removable prosthesis. Both implants were made of titanium, airborne-particle abraded with zirconium oxide, and etched with mineral acids. The implants were removed, preserving the bone around the implant threads, and replaced with two new implants, inserted in a prosthetically guided, correct position. The removed implants were histologically observed. Histologic analysis showed good bone-to-implant contact, mature bone with few marrow spaces, presence of direct connecting bridges between the periimplant bone trabeculae and the implant surface, and no inflammatory cells nor connective fibrous tissue ingrowth. This study showed that dental implants coated with a rough surface were properly osseointegrated, with no inflammatory signs nor connective fibrous tissue ingrowth, 8 months after placement.

Objective: This article describes the esthetic results in a paradigmatic case of hypomineralized enamel correction on both anterior and posterior teeth to establish a minimal intervention protocol for similar cases. Clinical considerations: The subject was initially provided with casein-calcium-phosphate mineral supplementation. Unpublished laboratory images collected as part of a previously published study depict the results of initial calcium-phosphate supplementation on molar incisor hypomineralization (MIH) molar enamel morphology and indicate that this procedure is mandatory in moderate/severe cases. Prior to defect restoration, in-office bleaching of the anterior segment was conducted with bioactivated Opalescence Boost. Filtek Supreme Ultra Universal Restorative was used as a masking agent, and Filtek A2 enamel was applied as the final layer. Conclusion: An 8-year follow-up period is necessary in most moderate/severe MIH cases involving orthodontics and bleaching. Keywords: MIH diagnosis, MIH supplementation, MIH treatment, molar incisor hypomineralization (MIH), orthodontic treatment, restorative treatment

Purpose: To evaluate the immediate and aged bond strength and interfacial nanolaekage of different adhesives and protocols on dental elements prepared with diamond burs and Er:YAG laser. Materials and Methods: Forty molar crowns were flattened and a standardized smear layer was created. Teeth were divided into two main groups according to the dentin cutting technique: 1. Er:YAG laser for 30 s at 30 Hz repetition rate, 250 mJ energy per pulse, and water spray irrigation set at level 8; and 2. diamond bur. Each group was then divided into subgroups according to the adhesive protocol: SG1: dentin etching for 15 s followed by universal adhesive application (All Bond Universal, Bisco); SG2: universal adhesive application (All Bond Universal); SG3: two-step self-etch adhesive application (Clearfil SE Bond 2, Kuraray Noritake); SG4: etching followed by 3-step etch-and-rinse adhesive application (Optibond FL, Kerr). After curing the adhesives, resin composite buildups of 4 mm were made and specimens were sectioned to obtain 1-mm-thick sticks in accordance with the μTBS test technique. Sticks were stressed to failure at baseline and after 6 months of storage in artificial saliva. Three teeth per group were prepared for nanoleakage interfacial analyses. Data were statistically analyzed with three-way ANOVA and Tukey's post-hoc test (p 0.05). Results: A significant difference in bond strengths was found for treatment, aging, and adhesive protocol. Nanoleakage analysis showed higher marginal infiltration in Er:YAG-treated groups both at baseline and after aging. Conclusions: Surfaces prepared with diamond burs presented higher bond strengths than did those prepared with Er:YAG laser. Adhesive protocols and aging could influence the adhesive-dentin interface. Further studies are necessary to validate the results obtained. Keywords: adhesion, adhesive interface, bond strength testing, Er:YAG laser