Search

6. EAO Consensus Conference 2021, online, 11 Feb 2021 - 12 Feb 2021; Clinical oral implants research 32(S21), 336-341 (2021). doi:10.1111/clr.13797 special issue: "Special Issue: The 6th EAO Consensus Conference 2021 / edited by: Irena Sailer, Björn Klinge, Henning Schliephake", Published by Wiley-Blackwell, Oxford

OBJECTIVES: The main objective of the study was to compare the accuracy of full-arch digital implant impressions for fixed dental prosthesis under in vitro and in vivo conditions. MATERIALS AND METHODS: Eight patients (five women and three men) with at least one edentulous arch and with 4-6 osseointegrated implants participated in this study. For each edentulous arch (n = 10), experimental screw-retained titanium bar with attached four scan bodies was fabricated. The bar containing four scan bodies was screw-retained intraorally on implants and scanned with Trios 3 intraoral scanner eight times (IOS group, in vivo). Then, the bar was attached to the master cast and scanned eight times again with the same intraoral scanner (MIOS group, in vitro). Finally, the bar with scan bodies was scanned 8 times with a laboratory scanner (reference). Precision and trueness were calculated for 3 distances and 3 angles between the scan bodies (1-2, 1-3, and 1-4) in IOS and MIOS groups. RESULTS: Precision and trueness for the largest distance (1-4) were found to be 44 ± 18 µm and 32 ± 19 µm for the IOS group and 31 ± 16 µm and 30 ± 14 µm for MIOS group, respectively. Precision and trueness for the angle between the most distant scan bodies (1-4) were 0.22 ± 0.14° and 0.18 ± 0.10° for the IOS group and 0.16 ± 0.11° and 0.07 ± 0.05° for MIOS group, respectively. CONCLUSIONS: Intraoral conditions moderately affected the precision and trueness of Trios 3 (3Shape) intraoral scanner. Results of in vitro accuracy studies cannot be directly transferred to the clinical field.

Monolithic zirconia implant-supported restorations connected to titanium bases or titanium inserts are increasing in popularity due to their application in a full digital workflow. These prefabricated abutments are connected to the all-ceramic superstructure by adhesive cementation. Although limited clinical data on the outcomes of this type of restoration are available, a few laboratory studies have shown possible debonding issues. This case report presents a bonding failure of a fixed dental prosthesis supported by titanium bases after short clinical use. A treatment alternative is also proposed using the available digital dental technology.

Purpose of Review The aim of this case report was to illustrate the clinical procedure integrating augmented reality (AR) for complex patient cases requiring full mouth rehabilitation. Recent Findings The introduction of AR technology to the fields of medicine and dentistry has led to numerous applications in education, surgery, and esthetics. Recently, a new AR software was introduced in esthetic dentistry which allows for real-time smile projection and thus improves communication with patients and the dental laboratory. Summary The presented case shows a patient with multiple missing teeth, diastemata, and an impaired masticatory and phonetic ability. After reconstruction of the posterior zone, the AR software was used for the conception of the esthetic zone, integrating the patient into the decision-making process. The result was an esthetic rehabilitation applying palatal and buccal veneers which corresponded to the chosen AR design. The patient appreciated the opportunity to pre-visualize a possible final outcome in an interactive way which increased his confidence in the chosen treatment. Further studies are needed to assess the precision and reproducibility of the described protocol.

The tasks of Working Groups 1 to 6 at the 4th Consensus Meeting of the Oral Reconstruction Foundation were to elucidate clinical recommendations for implant-supported full-arch rehabilitations in edentulous patients. Six systematic/narrative reviews were prepared to address the following subtopics: (1) the influence of medical and geriatric factors on implant survival; (2) the prevalence of peri-implant diseases; (3) the influence of material selection, attachment type, interarch space, and opposing dentition; (4) different interventions for rehabilitation of the edentulous maxilla; (5) different interventions for rehabilitation of the edentulous mandible; and (6) treatment choice and decision-making in elderly patients. Consensus statements, clinical recommendations, and implications for future research were determined based on structured group discussions and plenary session approval.

This in vitro study evaluated technical outcomes of monolithic zirconia implant-supported fixed dental prostheses (iFDPs) supported by different designs of titanium base abutments after aging and static load testing.Sixty three-unit monolithic zirconia (yttrium oxide partially stabilized tetragonal zirconia polycrystals; Y-TZP)iFDPs were produced and divided into four groups: group A-conical titanium base abutments for the prosthesis; group B-cylindrical titanium base abutments for the crown; group C-conical titanium base abutment for the prosthesis and cylindrical titanium base abutment for the crown; group D-cylindrical titanium base abutments for the prosthesis. The samples were subjected to an aging protocol and to continuous static loading until failure and analyzed visually and with specific software. The technical outcomes comprised the occurrence of debonding, screw loosening, deformation and fracture, abutment deformation and fracture, implant deformation and fracture, zirconia chipping and fracture, and bending moments. The Pearson chi-squared test (χAfter aging, a higher percentage of debonding (P = .042) and micromovement (P = .034) was recorded in group C (P = .042). The conical titanium base abutments had a higher debonding (P = .049) and a higher macromovement rate (P = .05). The static load test showed higher bending moments in group D (P = .001) and lower bending moments in group A (P = .001). Debonding was highest in group C (P = .001) and lowest in group A (P = .002). Complete loss of retention rate was highest in group C (P = .001). The conical titanium base abutment had the highest debonding rate (P = .001) and complete loss of retention (P = .001). The micromovement rate was the highest for cylindrical titanium base abutments for the crown (P = .001). The lowest screw loosening, zirconia chipping, and fracture rate (P = .001) and the highest screw deformation (P = .004) were recorded in group A. The screw deformation rate was lowest in the cylindrical titanium base abutments for the crown (P = .008).The mixed titanium base abutment design comprising one conical and one cylindrical abutment in Y-TZP iFDPs led to the highest debonding rate. The cylindrical titanium base abutment for the prosthesis provided a lower percentage of debonding and the highest load resistance.

STATEMENT OF PROBLEM Clinical trials are needed to evaluate the digital and conventional fabrication technology for providing fixed partial dentures (FPDs). PURPOSE The purpose of the second part of this clinical study was to compare the laboratory production time for tooth-supported, 3-unit FPDs by means of computer-aided design and computer-aided manufacturing (CAD-CAM) systems and a conventional workflow. In addition, the quality of the 3-unit framework of each treatment group was evaluated clinically. MATERIAL AND METHODS For each of 10 participants, a 3-unit FPD was fabricated. Zirconia was used as the framework material in the CAD-CAM systems and included Lava C.O.S. CAD software (3M) and centralized CAM (group L); CARES CAD software (Institut Straumann AG) and centralized CAM (group iT); and CEREC Connect CAD software (Dentsply Sirona) and centralized CAM (group C). The noble metal framework in the conventional workflow (group K) was fabricated by means of the traditional lost-wax technique. All frameworks were evaluated clinically before veneering. The time for the fabrication of the cast, the 3-unit framework, and the veneering process was recorded. In addition, chairside time during the clinical appointment for the evaluation of the framework was recorded. The paired Wilcoxon test together with appropriate Bonferroni correction was applied to detect differences among treatment groups (α=.05). RESULTS The total effective working time (mean ±standard deviation) for the dental technician was 220 ±29 minutes in group L, 217 ±23 minutes in group iT, 262 ±22 minutes in group C, and 370 ±34 minutes in group K. The dental technician spent significantly more time in the conventional workflow than in the digital workflow, independent of the CAD-CAM systems used (P

STATEMENT OF PROBLEM Clinical trials are needed to evaluate digital and conventional technologies for providing fixed partial dentures. PURPOSE The purpose of the first part of this clinical study was to test whether complete-arch digital scans were similar to or better than complete-arch conventional impressions regarding time efficiency and participant and clinician perceptions. MATERIAL AND METHODS Ten participants in need of a posterior tooth-supported 3-unit fixed partial denture were included. Three intraoral digital scanners and subsequent workflows (Lava C.O.S.; 3M [Lava], iTero; Align Technology Inc [iTero], Cerec Bluecam; Dentsply Sirona [Cerec]) were compared with the conventional impression method using polyether (Permadyne; 3M) and the conventional workflow. A computer-generated randomization list was used to determine the sequence of the tested impression procedures for each participant. The time needed for the impression procedures, including the occlusal registration, was assessed. In addition, the participant and clinician perceptions of the comfort and difficulty of the impression were rated by means of visual analog scales. Data were analyzed with the nonparametric paired Wilcoxon test together with an appropriate Bonferroni correction to detect differences among the impression systems (α=.05). RESULTS The total time for the complete-arch impressions, including the preparation (powdering) and the occlusal registration, was shorter for the conventional impression than for the digital scans (Lava 1091 ±523 seconds, iTero 1313 ±418 seconds, Cerec 1702 ±558 seconds, conventional 658 ±181 seconds). The difference was statistically significant for 2 of the 3 digital scanners (iTero P=.001, Cerec P

The aim of this study was to investigate the effects of saliva contamination and the cleaning of the bond surface of titanium base (ti-base) abutments on the bonding stability and retention force values. The bond surface of the ti-base abutments was treated with airborne-particle abrasion. After contamination, the ti-base abutments underwent different cleaning protocols: water spray (H2O), alcohol (ALC), suspension of zirconium particles (SZP), reapplied airborne-particle abrasion (APA), and a control condition without contamination and cleaning (CTR). All lithium disilicate crowns were bonded to the ti-base abutments using a primer and a self-curing composite. Bonded specimens underwent thermo-mechanical aging. Bond failure analysis and pull-off testing were performed. Bond failure occurred more frequently in groups H2O, ALC, SZP, and APA (p &lt, 0.05). Significant differences in retention force values were only found between CTR and ALC (p &lt, 0.05). Specimens which did not show bond failure after ageing had higher retention force values than the specimens that showed bond failure (p &lt, 0.05). Saliva contamination with cleaning can degrade the bonding properties to titanium. For the retention force values, only the protocol with alcohol after contamination could not restore the values.

Purpose: To evaluate survival, complication rates, and bending moments of one- and two-piece zirconia implants restored with different abutment materials and lithium disilicate crowns after aging, compared to titanium implants restored with titanium base-supported lithium disilicate crowns. Materials and methods: Sixty anterior crowns were either screwretained on two-piece titanium implants (C) and two-piece zirconia implants (T1, T2, T3) or cemented on one-piece zirconia implants (T4), resulting in 5 groups with 12 specimens each. For the screw-retained crowns, different abutment materials and implant connections were tested: titanium base with internal conical connection and horizontal joint component (C and T2), zirconia with internal hexagonal connection and horizontal joint component (T1), and polyetherketoneketone with internal hexagonal connection and horizontal joint component (T3). After artificial aging with thermocycling (5°C to 50°C) and chewing simulation (1,200,000 cycles, 49 N, 1.67 Hz), the surviving specimens were loaded until fracture, and the bending moments were calculated. Survival rates and respective differences during aging were analyzed with the Kaplan-Meier log-rank test, while complication rates were compared with chi-square tests. Bending moment data were evaluated using the Kruskal-Wallis test (α = .05). Results: Survival rates after artificial aging ranged from 75% (T1) to 100% (C and T4) without significant differences between the groups (P > .05). Only 41.5% of the surviving specimens were free of complications, while the remaining presented screw-loosening, loss of retention of crowns, or cracks on the crown or implant level. The complication rates varied significantly among the groups (P < .05). The mean bending moments were 173.7 × 20.1 (C), 114.5 × 20.1 (T1), 171.1 × 46.1 (T2), 258.1 × 147.4 (T3), and 194.7 × 30.9 Ncm (T4), and group T1 exhibited significantly lower median bending moment values than the other groups (P < .001). Conclusion: The zirconia one- and two-piece implants presented high survival rates after aging, yet the number of technical complications was high. New prosthetic solutions, such as titanium bases or polyetherketoneketone abutments, may offer a comparable treatment option to restore two-piece zirconia implants.

A 61-year-old healthy patient was referred for prosthetic rehabilitation in the maxilla and mandible. The primary wish of the very anxious patient was to improve the masticatory function and his aesthetic appearance with the least invasiveness and as efficiently as possible. Furthermore, he desired to receive a reliable long-term solution. The patient had no general medical restrictions and was a non-smoker. At the time of the first clinical examination, the patient presented nearly edentulous, with a few root remnants in the mandible and remaining wisdom teeth in the maxilla. The main objective of the treatment, hence, was to improve both his chewing function and the stability of the prostheses without invasive surgeries. After the removal of the root remnants and one of the two wisdom teeth (18), two new complete dentures were fabricated. Thereafter, 6 diameter reduced mini implants (SLA® one-piece self-tapping Straumann® Mini Implants made of Roxolid®, with a diameter of 2.4 mm and a length of 10 mm) were inserted in the maxilla, and 4 mini implants (SLA® one-piece self-tapping Straumann® Mini Implants made of Roxolid®, with a diameter of 2.4 mm and a length of 10 mm) were inserted in the mandible. After the implant insertion with good primary stability, the two new complete dentures were transferred into two implant-supported removable dental prostheses and retained by means of the transmucosal integrated attachment system of the mini implants (Optiloc®). At the 3-month follow-up visit, the patient was very satisfied with the outcomes, both from a functional and aesthetic point of view.

BACKGROUND There is limited knowledge regarding the strength of zirconia abutments with internal and external implant abutment connections and zirconia abutments supported by a titanium resin base (Variobase, Straumann) for narrow diameter implants. OBJECTIVES To compare the fracture strength of narrow diameter abutments with different types of implant abutment connections after chewing simulation. MATERIAL AND METHODS Hundred and twenty identical customized abutments with different materials and implant abutment connections were fabricated for five groups: 1-piece zirconia abutment with internal connection (T1, Cares-abutment-Straumann BL-NC implant, Straumann Switzerland), 1-piece zirconia abutment with external hex connection (T2, Procera abutment-Branemark NP implant, Nobel Biocare, Sweden), 2-piece zirconia abutments with metallic insert for internal connection (T3, Procera abutment-Replace NP implant, Nobel Biocare), 2-piece zirconia abutment on titanium resin base (T4, LavaPlus abutment-VarioBase-Straumann BL-NC implant, 3M ESPE, Germany) and 1-piece titanium abutment with internal connection (C, Cares-abutment-Straumann BL-NC implant, Straumann, Switzerland). All implants had a narrow diameter ranging from 3.3 to 3.5 mm. Sixty un-restored abutments and 60 abutments restored with glass-ceramic crowns were tested. Mean bending moments were compared using ANOVA with p-values adjusted for multiple comparisons using Tukey's procedure. RESULTS The mean bending moments were 521 ± 33 Ncm (T4), 404 ± 36 Ncm (C), 311 ± 106 Ncm (T1) 265 ± 22 Ncm (T3) and 225 ± 29 (T2) for un-restored abutments and 278 ± 84 Ncm (T4), 302 ± 170 Ncm (C), 190 ± 55 Ncm (T1) 80 ± 102 Ncm (T3) and 125 ± 57 (T2) for restored abutments. For un-restored abutments, C and T4 had similar mean bending moments, significantly higher than those of the three other groups (p

The recent evolution of digital technologies in dentistry has enabled virtual 3D diagnostic analysis of a dentition before treatment, allowing for virtual, minimally invasive treatment planning. In this report, an extensively worn dentition was 3D virtual analyzed at an increased vertical dimension of occlusion. Virtual waxing (exocad DentalCAD; Exocad) and subsequent analysis of the need for minimally invasive preparations were performed. Areas of each tooth without adequate clearance for the minimal thickness of a definitive restoration (set at 1.5 mm in the software), including the amount of tooth substance to be removed (GOM Inspect; GOM), were visualized in color. A preparation guide was virtually designed according to this diagnostic plan (3-matic; Materialise) and 3D printed (Connex3 Objet260; Stratasys) from resin (VeroMagenta RGD851; Stratasys). The teeth were minimally prepared using the guide, and the amount of preparation was validated by superimposing the scan of the prepared model on the initial scan and comparing it with the diagnostic plan.

OBJECTIVES: Working Group 5 was assigned the task to review the current knowledge in the area of digital technologies. Focused questions on accuracy of linear measurements when using CBCT, digital vs. conventional implant planning, using digital vs. conventional impressions and assessing the accuracy of static computer-aided implant surgery (s-CAIS) and patient-related outcome measurements when using s-CAIS were addressed. MATERIALS AND METHODS: The literature was systematically searched, and in total, 232 articles were selected and critically reviewed following PRISMA guidelines. Four systematic reviews were produced in the four subject areas and amply discussed in the group. After emendation, they were presented to the plenary where after further modification, they were accepted. RESULTS: Static computer-aided surgery (s-CAIS), in terms of pain & discomfort, economics and intraoperative complications, is beneficial compared with conventional implant surgery. When using s-CAIS in partially edentulous cases, a higher level of accuracy can be achieved when compared to fully edentulous cases. When using an intraoral scanner in edentulous cases, the results are dependent on the protocol that has been followed. The accuracy of measurements on CBCT scans is software dependent. CONCLUSIONS: Because the precision intraoral scans and of measurements on CBCT scans and is not high enough to allow for the required accuracy, s-CAIS should be considered as an additional tool for comprehensive diagnosis, treatment planning, and surgical procedures. Flapless s-CAIS can lead to implant placement outside of the zone of keratinized mucosa and thus must be executed with utmost care. ispartof: CLINICAL ORAL IMPLANTS RESEARCH vol:29 pages:436-442 ispartof: location:Denmark status: published

PURPOSE This study aims to test whether or not veneering of the submucosal part of zirconia abutments with pink dental ceramic affects radiographic and technical outcomes of implant-supported single crowns (ISSC). MATERIALS AND METHODS Single tooth implants were randomly restored with either pink-veneered zirconia abutments (test; n = 10) or non-veneered zirconia abutments (control group; n = 10) and all-ceramic crowns. At baseline (crown insertion), and 6- and 12-month radiographic and technical evaluations were performed including standardized x-rays and modified United States Public Health Service criteria (technical). Survival and complication rates were assessed for implants and restorations. Robust linear mixed model analysis was performed to investigate the effect of group and time-point on radiographic outcomes. RESULTS At 1 year, the survival rate for implants was 100% and 95% for ISSC. Most of the implants were placed subcrestally. Therefore, mean marginal bone levels decreased in both groups between implant insertion and baseline (p .005). At 6 months, one minor chipping occurred in the test group. At 1 year, three crowns (control) exhibited occlusal roughness. In addition, one abutment fracture occurred (test). The differences between test and control group were not statistically significantly different for any of the evaluated outcome measures (p > .05). CONCLUSIONS Veneering of the submucosal part of zirconia abutments did not affect biological and technical outcomes of ISSCs. Technical complications of the reconstructions, however, were frequent, resulting in a rate of 75% of the crowns being complication free.

To test whether or not pink veneering of the submucosal part of zirconia abutments influences clinical, microbiological and histological outcomes of cemented implant-supported single crowns (ISSC).A total of 20 patients with one single-tooth implant in the esthetic zone were included. Implants were randomly restored with either pink-veneered zirconia abutments (test group; n = 10) or non-veneered white zirconia abutments (control group; n = 10) and with adhesively cemented all-ceramic crowns. At the 6-month follow-up, soft tissue biopsies were prepared for histological evaluation and microbiological samples were collected around abutments and the respective contra-lateral teeth (in 10 of 20 patients). One year after the initiation of loading, clinical parameters were assessed. Robust linear mixed model and cumulative linked mixed model analyses were performed to investigate the effect of group and time-point on clinical and biological outcomes.Clinical evaluations revealed stable peri-implant soft tissues in terms of probing pocket depth, but a high BOP index (87.5% control; 80.0% test). No statistically significant differences were observed between the test and control group for any outcome measure (P 0.05). No major biological complications occurred during the observation period. Histological samples revealed a remarkable degree of inflammation in both groups without clear differences in qualitative histological features. Microbiological evaluation demonstrated a slightly higher bacterial count at implants compared to natural teeth at one year of loading without marked differences between groups.Limited by a small sample size and a relatively short observation period, pink-veneered zirconia abutments exhibited similar clinical, histological and microbiological outcomes as non-veneered zirconia abutments supporting cemented single crowns.

OBJECTIVES To evaluate the discoloration of the mucosa caused by different ceramic and metal-based materials. MATERIAL AND METHODS On six pig maxillae, trap-door flaps were prepared bilaterally. Different ceramic and metal-based specimens were placed underneath the flap. To simulate increasing mucosal thicknesses (MC), connective tissue grafts (CTGs) were harvested. Spectrophotometric measurements were performed prior to flap elevation (TBL ) and for each material under the flap alone (1 mm MC) (TMC1 ), with a 1-mm CTG (2-mm MC) (TMC2 ) and with a 2-mm CTG (3-mm MC) (TMC3 ). Tested materials were as follows: Zr1 (zirconia), Zr2 (zirconia + pink ceramic), Zr3 (zirconia), Zr4 (fluorescent zirconia), Zr5 (zirconia), Zr6 (high translucent zirconia), Zr7 (low translucent zirconia) and Zr8 (low translucent zirconia), Gol (gold alloy), Ti1 (titanium alloy), Ti2 (anodized gold-shaded titanium alloy) and Ti3 (anodized pink-shaded titanium alloy). Color differences (ΔE) were calculated comparing the measurement of the native tissue (TBL ) and the measurements with varying mucosal thicknesses (TMC1-3 ). RESULTS For ceramic materials, the median ΔE values for the different time-point comparison ranged as follows: 3.80 (Zr4) - 7.47 (Zr2) (pooled); 3.15 (Zr4) - 8.13 (Zr2) (TBL -TMC1 ); 3.39 (Zr4) - 7.24 (Zr2) (TBL -TMC2 ); 4.31 (Zr8) - 6.99 (Zr2) (TBL -TMC3 ). For metal-based materials, the median ΔE values were as follows: 4.20 (Gol) - 5.82 (Ti3) (pooled); 3.21 (Gol) - 13.56 (Ti1) (TBL -TCM1 ); 4.0 (Ti1) - 5.27 (Gol) (TBL -TCM2 ); 3.11 (Ti1) - 5.11 (Gol) (TBL -TCM2 ). The comparison of the materials and the time points showed in the nonparametric linear mixed model a significant interaction effect between material and time point (P < 0.001). The side was not a significant main effect, nor as term in an interaction with the other two effects. CONCLUSIONS Reconstructive materials result in an evident discoloration of the mucosal tissue, tending to decrease with increasing mucosal thickness. The use of fluorescent zirconia (ceramic materials) or gold alloy (metal-based materials) lead to the least discoloration.

The aim of this study was to test whether veneering of the submucosal part of zirconia abutments using pink veneering ceramic positively influences the color of the peri-implant mucosa. Single-tooth implants were restored with either white zirconia abutments (control group) or pink-veneered zirconia abutments and all-ceramic crowns. Esthetic outcome measurements included a spectrophotometric evaluation of the peri-implant mucosal color. Test and control groups induced a visible discoloration of the peri-implant mucosa after the insertion of the abutments and following cementation of the crowns compared to natural teeth. The calculated color differences were above the clinically visible threshold value and were more favorable for the control group, although not statistically significant. It is concluded that veneering of zirconia abutments with pink veneering ceramic failed to positively influence the esthetic outcome, mostly due to a decrease of the brightness compared with the control group.