This article evaluated the sealing capacity of single crowns made of a new zirconia (Katana STML, Kuraray Noritake) when cemented with two different cement types and two different marginal preparation types. Forty intact human anterior teeth, extracted for periodontal reasons, were used. Each sample was prepared with two margin preparations: knife-edge (KE) on one half of the tooth and chamfer (CH) on the other half. Based on the type of cement used, abutments were randomly distributed into one of two groups: Group 1 used resin cement (Panavia V5, Kuraray Noritake), and Group 2 used reinforced glass-ionomer cement (FujiCEM 2, GC). A digital workflow was utilized for crown fabrication. After the cementing procedures, samples were processed, and microleakage and scanning electron microscopic observations were made. Microleakage varied significantly depending on the type of cement combination used. Group 1 samples showed less microleakage (medians: 0.76 for CH and 0.51 for KE in Group 1, and 4.1 and 3.45 for Group 2, respectively) than Group 2 specimens; the difference was statistically significant (P < .000). KE preparation showed less microleakage than CH, although no statistically significant differences were found (P < .0558). Under microscopic observations, some samples showed internal fractures within the zirconia material. KE and CH seal the margin of zirconia crowns similarly. The resin cement system ensured better adhesion than reinforced glass-ionomer cement.

Aim: Recording maximum intercuspal position (ICP) is critical for many dental procedures. Digital ICP from intraoral scanners (IOSs) produces variable results. This study investigated the sources of error in recording ICP using an IOS and a recently reported method. Materials and methods: A set of dentate models was scanned three times in a Rexcan DS2 scanner. The models were then scanned six times with a Cerec Omnicam IOS. For each scan, 10 bilateral ‘bite’ scans were performed (n = 6 x 10 bite registrations). Three key points were identified on the first intraoral scan and automatically transplanted onto all subsequent scans. The key point method was validated by using a ‘secondary’ key point transplantation from each scan back to the three laboratory scans, where the location of each point was compared using one-way analysis of variance. Full-arch errors on the intraoral scans were identified by comparing the intermolar key point distances on all intraoral scans against the ‘gold standard’ model scans. Precision of the virtual occlusion was identified by comparing the distance between all upper-lower key point pairs for all intraoral scans using intraclass correlation. Results: Automatic key points were transplanted to model scans with standard deviations (SDs) in location of ≤ 0.003 mm (upper [maxillary]) and ≤ 0.004 mm (lower [mandibular]) arch. The intermolar width of the intraoral scans had a mean error of 0.183 (± 0.061) mm (upper) and 0.017 (± 0.092) mm (lower) arch. Interocclusal key point separation showed poor reliability across groups, but good precision (SD < 0.022 mm) within groups. Conclusion: Automatic key points allowed valid linear distance comparisons across repeated scans. Poor trueness and precision in the full-arch intraoral scans adversely affected interocclusal registrations. Bite scan precision had a less detrimental effect on interocclusal registration. Keywords: occlusion, articulation, intraoral scanner, accuracy, precision, measurement

Purpose: To evaluate the influence of hydrofluoric acid (HF) concentration and etching time on the microshear bond strength (µSBS) of RelyX Unicem 2 (3M Oral Care) to VITA Suprinity (Vita Zahnfabrik; zirconia-reinforced lithium-silicate glass ceramic: ZLS) and IPS e.max CAD (Ivoclar Vivadent; lithium-disilicate glass ceramic: LD). Materials and Methods: Forty-eight bars each were fabricated of ZLS and LD with Cerec InLab MC-XL. For each material, 8 groups were formed with respect to etching time (20, 40, 60, 120 s) and HF concentration (4.9% and 9.5%). In each group, after etching and silanization, 15 cylindrical specimens of RelyX Unicem 2 were built up for µSBS testing with a special device. Data were analyzed using three-way ANOVA. Failure modes were assessed using an optical stereomicroscope, classified as adhesive, cohesive in resin or ceramic, or mixed. Failure modes were statistically analyzed using Fisher's Exact Test. One bar per group was prepared for SEM observation of the etched surface. Results: ZLS showed significantly higher bond strengths than LD (p < 0.001). Etchant concentration was an influential factor with superior strengths after 4.9% HF etching (p = 0.009). Etching time did not significantly affect adhesion (p = 0.066). The material-etching interaction was statistically significant (p = 0.004). Particularly for ZLS, 4.9% HF etching obtained significantly higher bond strengths than did 9.5%. By using 4.9% HF, adhesion was significantly higher on ZLS than on LD. Conclusion: Material and HF concentration influenced the adhesion between RelyX Unicem 2 composite cement and lithium-silicate glass ceramics. Etching time was not an influential factor. The use of 4.9% HF for 20 s proved to be the most effective etching treatment of the intaglio surface. Keywords: CAD-CAM, hydrofluoric acid, IPS e.max CAD, microshear bond strength, VITA Suprinity

Purpose: A growing recognition of the importance of oral health-related quality of life (OHRQoL) has led to the development of several instruments to measure their relationship with health. The objective of this review was to update the knowledge on the general and psychometric characteristics of the instruments to measure the quality of life (QoL) related to oral health that emerged after publication in 1997 of the results of the conference 'Measuring Oral Health and QoL'. Materials and Methods: A bibliographic search was carried out to identify publications published in January from 1998 to June 2018, using EMBASE, PubMed, Scopus, CINAHL and Web of Science databases. Specific criteria were established based on international reference frameworks for the inclusion, collection, and analysis of general and psychometric properties of the instruments. Results: 233 articles were identified, of which 10 met the eligibility criteria and were included. All the instruments were multidimensional, presented psychometric properties and were mostly based on prior measurement tools and the classification of impairments and disabilities. All studies presented information on the internal consistency of their instruments. Validity to discriminate was also rated positively in all of the instruments except OHRQoL-UK instrument. Among the instruments, the criterion that was found to be least was a response to change, as only three instruments met the criteria. Reliability and construct validity criteria were also present in most of the studies. Conclusion: The dental profession has shown great progress towards a more comprehensive measurement of the oral health needs of the population, it is necessary to move from focusing on sick patients and theories of disabilities to incorporating healthy patients and resource-based theories and capacities in their measurements of OHRQoL, that would improve patient safety, quality of care and risk management, and improve clinical decision making for healthcare professionals. Keywords: decision making, oral health, patient-based outcomes, patient safety, quality of life, questionnaire

The objective of this study was to evaluate the influence of two finish lines on the fracture resistance and periodontal response of porcelain zirconia crowns. Ethical committee approval was obtained, and 50 zirconia single crowns were placed in posterior regions. Abutments were randomly distributed into two groups: Group 1 (feather-edge preparation) and Group 2 (chamfer preparation). Patients were recalled after 1 month, 6 months, and 1, 2, 3, and 4 years. The function, esthetics, and marginal adaptation of the restorations were evaluated. Bleeding on probing (BoP) and distance of margins from the bone crest were recorded. Statistical analyses were performed for survival and success rates. Group 1 had an 80% success rate (21/25 crowns) and a 96% survival rate (24/25 crowns; 1 encountered irreparable fracture of ceramic layer); Group 2 had a 76% success rate (20/25 crowns) and a 100% survival rate (25/25 crowns). Chippings were noticed on 4 crowns in Group 1 (one crown replacement). Five chippings occurred in Group 2, without any replacement. There were no statistically significant differences between the two groups. BoP was found in 18 of the 25 crowns in Group 1 (72%) and in 12 of the 25 crowns in Group 2 (48%). A statistically significant correlation between BoP and the distance of the margin to the bone crest was found. It was concluded that: (1) clinical survival and success rates of the two preparation methods on crowns are not significantly different; (2) due to the statistically significant correlation between BoP and the distance of the margin to the bone crest, margins should be placed at least 3 mm from the bone crest; and (3) higher probability of BoP is expected in cases with feather-edge preparation.

Purpose: To evaluate the bonding ability of self-adhesive and dual-cure resin cement systems applied to zirconia materials of different translucency in combination with each other and with titanium. Materials and Methods: Computer-aided design/computer-assisted manufacture (CAD/CAM) disks of three different zirconia materials (Zenostar MO 0 [medium opacity], MT 0 [medium translucency], and T 1 [translucent], Wieland Dental) were milled and hard sintered in order to obtain cylindrical samples of either 12 mm high × 12 mm diameter (used as a substrate) or 12 mm high × 8 mm diameter (to be bonded to the substrate). CAD/CAM disks of titanium (Starbond Ti4 Disc, S&S Scheftner) were milled in order to obtain a cylinder shape (12 mm high × 8 mm diameter to be bonded to the zirconia substrate). The bonding surfaces were sandblasted with alumina particles (70 μm/2 ATM). Two resin cement systems were tested in this study: a self-adhesive resin cement (SpeedCEM Plus, Ivoclar Vivadent) and a dual-cure resin cement (Variolink Esthetic DC, Ivoclar Vivadent) in combination with a primer (Monobond Plus, Ivoclar Vivadent). The smaller cylinders were bonded to the substrate following the manufacturer's instructions. After 24 hours at 37°C storage, each specimen was subjected to shear bond strength testing in a universal testing machine. The substrate was fixed to the machine, and shear force was applied to the small cylinder close to the bonding interface. Shear bond strength data were statistically analyzed by a three-way analysis of variance (ANOVA) followed by the Tukey test for post hoc comparison (P < .05). Results: No significant differences were found between substrates in the shear bond strength test (P = .078). Variolink Esthetic DC showed a statistically significantly higher bond strength compared with the SpeedCEM Plus (P = .001) with the exception of Zenostar MT substrate (P = .014). Conclusion: The resin cement systems showed high shear bond strength values when zirconia was resin bonded to either titanium or the corresponding zirconia substrate. Different zirconia translucencies did not affect the bond strength. The use of MDP primer and a dual-cure cement showed statistically significantly higher strength compared with the self-adhesive resin cement system with the only exception being the bonding of the translucent zirconia Zenostar MT. Keywords: cubic phase, MDP, sandblasting, self-adhesive, shear bond strength test, titanium, translucent zirconia

Purpose: To test a minimally invasive flap in the lateral approach for maxillary sinus floor elevation when compared to a trapezoidal flap. Materials and methods: Each patient received a bilateral sinus elevation procedure based on two different randomly allocated surgical approaches according to a split-mouth design: in the test side, a horizontal incision at mucogingival line was realised; in the control side, a trapezoidal flap was elevated to prepare the lateral window. Each sinus was filled using deproteinised bovine bone and the window covered with a collagen membrane. Implants were inserted according to a two-stage technique 6 months after sinus elevation procedures, submerged and then loaded after 6 months with definitive screw-retained metal-ceramic prostheses. Patients were followed up to 4 months post-loading. Outcome measures included: implant and prosthesis failures, complications, peri-implant marginal bone level changes, residual bone height and width, recorded before sinus augmentation and 180 days post-intervention by computed tomography (CT) scans, surgical times and patient discomfort data, assessed using a visual analogue scale (VAS) diagram for each treated side at 1, 7, 14 and 30 days of follow-up. Results: Seventeen patients were enrolled in this trial and none dropped out. Five completely edentulous patients were treated with full-arch prosthetic restorations (Toronto dental prosthesis) and 12 patients with partial metal-ceramic screw-retained prostheses. In total 72 implants were inserted, 37 in the test group and 35 in the control group. No prosthesis or implant failures occurred. A total of seven patients showed complications: five of them had complications in both test and control sides. Eight complications were detected in each group. During maxillary sinus elevation procedures, nine interventions (four from the test group and five from the control group) were affected by intrasurgical complications (six membrane perforations and three severe bleedings); post-surgical complications occurred to three patients (one submucosal emphysema in a patient from the test group, one wound dehiscence and a graft infection both recorded in the control group); a total of four implants in two patients in the test group, versus three implants from one patient in the control group showed peri-implant mucositis. There were no statistically significant differences in complications between the two groups (P = 1.00; 95% confidence interval [CI]: 0.15-3.11). Patients from the control group, at 4 months after loading, lost on average 0.53 mm (standard deviation [SD] 0.27; 95% CI: 0.40-0.65), and patients from the test group lost on average 0.66 mm (SD 0.27; 95% CI: 0.53-0.78); the difference was not statistically significant (mean difference: 0.07 mm; SD 0.34; 95% CI: −0.03-0.17; P = 0.102). Significant values for bone augmentation in height, 9.26 mm (SD 1.46; 95% CI: 8.56-9.95) in the test group and 9.38 mm (SD 1.95; 95% CI: 8.45-10.30) in the control group, and width, 1.68 mm (SD 1.04; 95% CI: 1.18-2.20) in the test group and 1.60 mm (SD 1.27; 95% CI: 0.99-2.20) in the control group, were found from the 180-day CT scans. No statistically significant differences were detected between the two groups, either for the bone augmentation data (difference: 0.27 mm; 95% CI: 0.15-0.38; P = 0.60) or for the bone width values (difference: 0.02 mm; 95% CI: 0.07-0.11; P = 0.67). A significant reduction in the total surgical time was found in the test group (mean difference: 6.64 minutes; SD 4.32; 95% CI: 4.58-8.69), with the difference being statistically significant (P = 0.009). Evaluation of patients' postoperative discomfort showed a significant preference for the test procedure: at 1 day the VAS value was 4 (interquartile range [IQR] 2 to 5) in the test group; in the control group the VAS score was 5 (IQR 4 to 8). The intergroup difference was statistically significant (P = 0.002). At the 7-day follow-up, the VAS value was 1 in the test group (IQR 0 to 3) and 3 in the control group (IQR 0 to 7), this difference was statistically significant (P = 0.003). No differences were detected at 14 and 30 days (P > 0.05). Conclusions: A minimally invasive approach to access the sinus cavity can be as successful as a conventional trapezoidal flap in maxillary sinus floor elevations. Keywords: patient-centred outcome, sinus elevation, surgical procedure, wound healing Conflict of interest statement: The authors declare that they have no conflicts of interest; they do not have any financial interest in products cited in the manuscript. The authors were ful

Aim: To evaluate the marginal adaptation and internal fit of milled fiber post and cores using different scanning methods. Materials and methods: Thirty typodont tooth models (Nissin) with pulp cavity were endodontically treated and prepared to receive 30 fabricated fiber post and cores. Three different methods of scanning were used (n = 10): an intraoral scanner (IOS) (Trios 3; 3Shape) to directly digitalize the post space (Group T) and a laboratory scanner to indirectly digitalize the resin pattern (Group RP) and the silicone impression (Group S) of the post space. All the specimens were examined using an optical microscope for the measurement of the vertical marginal discrepancy (VMD), and five in each group were scanned using microcomputed tomography (µCT) for the assessment of the VMD, the internal fit at the corner (IFC), post apex (PA), and at four horizontal cross-sections (CS1-4) inside the canal. All data were analyzed using mixed-design ANOVA, followed by pairwise testing to identify the differences (α = 0.05). Results: Statistical analysis revealed that Group T was associated with the smallest cement space compared with Group RP (P = 0.001) and Group S (P < 0.001) for VMD using µCT or direct microscopy (OM) (P < 0.001). Similarly, the cement space for Group T was smaller than that of Group S (P = 0.039) when measured at the IFC (µCT), and smaller than Group RP (P = 0.025) when measured at CS1-4 (µCT), with CS1 larger than CS3 (P = 0.015). There was no significant difference at PA (P = 0.271). Conclusion: Better adaptation was achieved with a complete digital workflow. Scanning the resin pattern or the silicone impression introduced more variables in the digital process or milling of a one-piece fiber post and core. Keywords: CAD/CAM, fiber post, post and core, intraoral scanner (IOS), extra-fine milling, prosthodontics

Intraoral digital impression is a viable alternative to conventional impression techniques and has been proven to be even more accurate than conventional materials. Nevertheless, there are cases in which the rheologic properties of conventional materials can be helpful. This article describes a method to overcome an insufficient sulcus-depth reading of intraoral scanners in challenging cases.

Purpose: Zirconia (ZrO2) and titanium nitride (TiN) implant abutments were introduced mainly for esthetic purposes, as titanium's gray color can be visible through mucosal tissues. This study was aimed at assessing whether ZrO2 and TiN abutments could achieve better esthetics in comparison with titanium (Ti) abutments, regarding the appearance of soft tissues. Materials and Methods: Ninety patients were included in the study. Each patient was provided with an implant (OsseoSpeed, Dentsply Implant System). A two-stage surgical technique was performed. Six months later, surgical reentry was performed. After 1 week, provisional restorations were screwed onto the implants. After 8 weeks, implant-level impressions were taken and soft tissue thickness was recorded, ranking thin (≤ 2 mm) or thick (> 2 mm). Patients were randomly allocated to three experimental groups, based on abutment type: (1) Ti, (2) TiN, and (3) ZrO2. After 15 weeks, the final restorations were delivered. The mucosal area referring to each abutment was measured for color using a clinical spectrophotometer (Easyshade, VITA); color measurements of the contralateral areas referring to natural teeth were performed at the same time. The data were collected using the Commission Internationale de l'Eclairage (CIE) L*a*b* color system, and ΔE was calculated between peri-implant and contralateral soft tissues. A critical threshold of ΔE = 3.7 was selected. The chi-square test was used to identify statistically significant differences in ΔE between thin and thick mucosal tissues and among the abutment types. Results: Three patients were lost at follow-up. No statistically significant differences were noticed as to the abutment type (P = .966). Statistically significant differences in ΔE were recorded between thick and thin peri-implant soft tissues (P < .001). Only 2 out of 64 patients with thick soft tissues showed a ΔE higher than 3.7: 1 in the TiN group and 1 in the ZrO2 group. All the patients with thin soft tissues reported color changes that exceeded the critical threshold. Conclusion: The different abutment materials showed comparable results in terms of influence on soft tissue color. Regarding peri-implant soft tissue thickness, the influence of the tested abutments on soft tissue color became clinically relevant for values ≤ 2 mm. Keywords: customized abutment, gingival color, implant biotype, titanium, titanium nitride, zirconia