Stock Abutments Research Articles

Impact of cement type and abutment height on pull-off force of zirconia reinforced lithium silicate crowns on titanium implant stock abutments: an in vitro study

BackgroundPull-off forces of cement-retained zirconia reinforced lithium silicate (ZLS) in implant-supported single crowns on stock titanium abutments with respect to abutment height and implant cement were evaluated and compared.MethodsPull-off force of ZLS crowns on stock titanium abutments was evaluated concerning dental cement and abutment height. A total sample size of 64 stock abutments with heights of 3 mm (n = 32) and 5 mm (n = 32) was used. The ZLS crowns were cemented with four different types of cement (one temporary, two semi-permanent, and one permanent). After cementation, water storage, and thermocycling each sample was subjected to a pull-off test using a universal testing machine.ResultsThe temporary cement showed the least pull-off force regardless of abutment height (3/5 mm: means 6 N/23 N), followed by the semi-permanent methacrylate-infiltrated zinc oxide cement (28 N/55 N), the semi-permanent methacrylate-based cement (103 N/163 N), and the permanent resin composite cement (238 N/820 N). Results of all types of cement differed statistically significantly from each other (p ≤ .012). The type of implant cement has an impact on the pull-off force of ZLS crowns and titanium abutments.ConclusionsPermanent cements present higher retention than semi-permanent ones, and temporary cements present the lowest values. The abutment height had a subordinate impact.

Effect of abutment finish lines on the mechanical behavior and marginal fit of screw-retained implant crowns: An in vitro study

Statement of problemThe design of the implant-abutment connection has been widely researched, but the impact of different crown-abutment geometries remains unclear. PurposeThe purpose of this in vitro study was to evaluate the effect of different crown-abutment margin geometries on the mechanical behavior and fit of screw-retained implant-supported single-crown restorations by using mechanical static and fatigue tests and mastication simulation. Material and methodsA total of 45 cobalt-chromium premolar-shaped metal frameworks were fabricated for single-unit implant-supported screw-retained restorations on stock abutments and internal hexagon Ø4.25×11-mm cylindrical implants. They were divided into 3 groups according to margin geometry: S, shoulder; C, chamfer; and F, feather-edge. Three static load until fracture and 24 dynamic load tests were performed by using the International Organization for Standardization 14801:2016 standard (ISO 14801:2016) (number of cycles limit: 5×106 cycles, frequency: 6 Hz). The ProFatigue software program was used to optimize the procedure (S, n=12 specimens; C, n=7 specimens; and F, n=5 specimens). Six additional specimens from each group were subjected to a mastication simulation (limit number of cycles: 1×106 cycles, cyclic loading from Pmin=30 N to Pmax=300 N, frequency: 6 Hz). Results from the fatigue tests were reported descriptively, and the Fisher exact test was used to analyze the difference in failure modes. Data from maximum misfit were evaluated by photogrammetry and statistically analyzed with the Anderson-Darling test and the Kruskal-Wallis and Dunn multiple comparison tests (α=.05). ResultsThe fatigue limit was 456 N for group S, 512 N for group C, and 514 N for group F. The mean ±standard deviation misfit was 2.6 ±0.1 μm for group S, 3.8 ±1.1 μm for group C, and 3.6 ±0.8 μm for group F. Differences in misfit between groups S and C and between groups S and F were statistically significant (P<.05). ConclusionsCrown-abutment connections with chamfer and feather-edge margins showed better mechanical behavior, while shoulder margin exhibited better fit. However, high levels of fit were achieved for all the evaluated geometries.

Analysis of the Titanium-Zirconia Implant- Abutment Micro-Gaps

Background: The implant–abutment micro-gap has been investigated as a potential etiological factor for peri-implant diseases. Purpose: The aim of this study was to determine the marginal accuracy of different zirconia CAD/CAM abutments placed on external hex implants. Materials &amp; methods: Twelve external hex implants (4.1mm) were used from the same company. The samples were divided into four groups: group 1) 4 mm diameter anti-rotational (AR) stock titanium abutments (n = 4); group 2) scanned (3Series, Dental Wings) and milled (RCS-1, Röders GmbH) 4 mm diameter zirconiaabutments (n = 4); group 3) scanned (3Series, Dental Wings) and milled (CNC 240, Lava) 4mm diameterzirconia abutments (n = 4); and, group 4) two piece 4.1 mm diameter stock abutments (Ti-base, CEREC, Sirona) (n=4), and torqued according with the manufacturer’s instructions (30Ncm, 20Ncm, 20Ncm &amp; 35 Ncm, respectively). The samples were placed in a sample holder and segmented longitudinally. The implant-abutment gap was measured in 6 different pre-determined locations using optic microscopy. Results: One-way ANOVA statistical analysis was conducted and showed that the micro-gaps in the group 1 samples were not significantly different when compared with the micro-gaps in group 4 samples. However, a significant difference (p &lt; 0.05) was found between the micro-gaps when using titanium abutments (groups 1 &amp; 4) compared to zirconia abutments (group 3). Conclusion: Within the limits of this study, it was concluded that zirconia abutments cannot be milled with the same degree of precision as the metal abutments. The mechanical effects of marginal implant-abutment microgap and risk of microbial infiltration should be evaluated in clinical investigations. Keywords: Dental implant; Abutment interface;Microleakage.

Effect of virtual cement gap settings on the marginal fit of cemented resin-ceramic crowns on implant abutments

Statement of problemAgreement on the perfect virtual cement space value for computer-aided design and computer-aided manufacturing (CAD-CAM) implant-supported resin-ceramic crowns with the best marginal adaptation is lacking. The range of cement gap settings in some CAD design software programs is wide (0 to 200 μm), and manufacturer recommendations regarding the best cement gap setting for certain types of ceramics is not specific. PurposeThe purpose of this in vitro study was to evaluate the effect of virtual cement gap settings on the marginal fit of cemented resin-ceramic crowns on implant abutments. Material and methodsThirty implant analogs and matching stock abutments were coupled and implanted into autopolymerizing acrylic resin blocks. Three groups (n=10) of resin-ceramic molar crowns with 3 different virtual cement space settings (40, 60, and 100 μm) were designed by using a CAD design software program. The crowns were cemented over their corresponding abutments under a static load by using a specially designed cementing device. A scanning electron microscope was used to measure the mean vertical marginal gap (MG) for each group, where a total of 120 measurements for each of the 3 groups (12 sites per crown and 10 crowns per group) were evaluated. One-way analysis of variance and the post hoc Tukey pairwise comparison tests were used to analyze the data (α=.05). ResultsA significant difference (P<.001) was found between the MG values of the resin-ceramic implant-supported crowns fabricated by using the 3 cement space settings. The smallest MG was obtained with the 60-μm setting as compared with the 40-μm and 100-μm settings. ConclusionsA limited inverse relation was found between the MGs of CAD-CAM-fabricated resin-ceramic implant-supported crowns and the cement gap settings in the exocad software program. The smallest MGs were obtained when a 60-μm cement space value was used (P<.001).

Effect Of Different Milling Devices On Marginal Fit Of CAD-CAM Zirconia Copings On Implant Stock Abutments.

To compare the marginal fit and internal surface roughness of CAD/CAM zirconia copings milled with 3- and 5-axis milling devices. Forty titanium implant stock abutments (4.8 mm in diameter, 4 mm in height) screwed to dental implants (4.1 mm in diameter) embedded in resin were considered phantoms and included in this in vitro study. All 40 phantoms were scanned with the same intraoral scanner, from which images of the virtual wax-up of zirconia copings were obtained and exported as standard tessellation language (STL) files. From each resulting STL file, two copings were milled: one using a 3-axis milling device, and the other using a 5-axis milling device. After milling, zirconia copings underwent high-speed sintering before being analyzed for marginal fit (ie, marginal gap measurement), and internal surface roughness was assessed with a scanning electron microscope (SEM). Statistical comparisons between groups were assessed with Mann-Whitney test. Median marginal gap values were 34.80 μm (95% CI: 0.00 to 173.98) for the 5-axis milling device group and 141.97 μm (95% CI: 82.13 to 163.46) for the 3-axis milling device group. A statistically significant difference in marginal gap was found between both milling device groups (P = .039). In addition, qualitative SEM analysis indicated higher internal surface roughness for the 3-axis milling device group. Within the limitations of this study, the present findings suggest that 5-axis milling devices outperform 3-axis milling devices for milling CAD/CAM zirconia copings from intraoral scans of implant stock abutments.

Fracture resistance of cement-retained and screw-cement–retained milled posterior crowns with screw-access hole preparations before and after firing: An in vitro study

Statement of problemWhen a cement-retained lithium disilicate crown needs to be removed, perforation is needed to reach the abutment screw. How this process affects its strength is unclear. PurposeThe purpose of this in vitro study was to evaluate the fracture strength of milled lithium disilicate implant crowns with screw-access holes created before and after the firing stages. Material and methodsNine implant replicas with stock abutments were embedded in acrylic resin. Forty-five lithium disilicate (IPS e.max CAD) crowns were designed, milled, and divided into groups. The control group had no screw access, the blue state group had the screw access created in the intermediate phase of the ceramic, and the postfiring group had the screw access created after firing. The crowns were cemented with a self-adhesive resin cement, placed in an incubator for 24 hours and then thermocycled. The screw-access holes were sealed with composite resin. The crowns were loaded to failure with a universal testing machine using a 1- mm-diameter ball at a crosshead speed of 0.5 mm/min and a 5-kN cell load. Data were analyzed by ANOVA and the Tukey post hoc test (α=.05). ResultsScrew-access holes created before and after firing stages had a significant effect on the fracture resistance of lithium disilicate crowns (P=.002). No difference in fracture resistance was observed between the control group and the blue state group (P>.05), while the fracture resistance of the postfiring group was significantly lower than that of the control group and the blue state group (P<.05). ConclusionsThe fracture strength of lithium disilicate crowns was not affected by a screw-access hole created during the blue state of the ceramic followed by repair with composite resin. Creating a screw-access hole after firing the ceramic reduced fracture strength.

Fabrication of additively manufactured custom impression copings based on stock abutments

This article describes a dental implant impression technique using custom impression copings. The implant impression coping was designed by using a dental computer-aided design software program and manufactured by using additive methods. The impression copings were cemented to stock abutments, and the assemblies were used to make the definitive pick-up impression.

Comparison of residual cement between CAD/CAM customized abutments and stock abutments via digital measurement in vitro

OBJECTIVE To compare the residual cement between computer aided design/computer aided manufacturing customized abutments (CCA) and stock abutments (SA), and to evaluate the feasibility of digital measurement for residual cement volume by three-dimensional scanning. METHODS Twenty master models needed in this study were all taken from one 47-year-old patient with arrested periodontitis, who had already had an implant placed at his right upper central incisor site in the Department of Periodonto-logy, Peking University School and Hospital of Stomatology. After 4 weeks of soft tissue conditioning by means of customized healing abutment, the height of peri-implant soft tissue was measured, from the implant platform to mucosal margin, as 5 mm. Using customized impression coping, the impression was taken and twenty models were fabricated and allocated to 4 groups according to the type of abutments: CCA1 (5 mm transmucosal height CCA, with margin at tissue level), CCA2 (4 mm transmucosal height CCA, with 1 mm submucosal margin), SA1 (3 mm transmucosal height SA, with 2 mm submucosal margin) and SA2 (1 mm transmucosal height SA, with 4 mm submucosal margin). Crowns were cemented to the abutments, which were seated on the working models. Excess cement was removed by a prosthodontic specialist. Thereafter, the volume of residual cement was evaluated by using three-dimensional scanning technique. The area proportion of residual cement was calculated on photographs taken by a single lens reflex camera. The weight of residual cement was weighed by an analytical balance. And the correlation of residual cement volume data with residual cement area proportion or weight of residual cement acquired by traditional methods was analyzed. RESULTS Residual cement was observed on all the experiment samples. The residual cement volume of CCA was significantly less than that of SA [(0.635 3±0.535 4) mm3vs. (2.293 8±0.943 8) mm3, P 0.75, P < 0.001). CONCLUSION These in vitro results suggest that CCA minimized the residual cement more effectively than SA. The method to digitally evaluate the residual cement volume is feasible, but its validity and reliability need to be further studied.

Effect of varying levels of expertise on the reliability and reproducibility of the digital waxing of single crowns: A preliminary in vitro study

Statement of problemThe digital waxing of single crowns can be affected by the quality of intraoral scans and use of computer-aided design (CAD) software programs. However, clinical outcomes of the resulting crowns are also affected by computer-aided manufacturing (CAM) methodologies. Studies on the effect of different levels of expertise on digital waxing are lacking. PurposeThe purpose of this in vitro study was to assess the impact of different levels of expertise on the reliability and reproducibility of margin outlining during digital waxing. Material and methodsThirty analogs of implant stock abutments (Ø4.8×4 mm) were embedded into resin blocks. To simulate different clinical situations, abutments were divided into 3 groups: 10 abutments (group GOS) received artificial gingiva and were scanned with an open system intraoral scanner, while 10 abutments with (group GIS) and 10 abutments without artificial gingiva (group IS) were scanned with an intraoral scanner within an integrated CAD-CAM system. All resulting standard tessellation language (STL) files were used by 2 different observers (an experienced CAD professional and a clinician with basic CAD knowledge) to digitally design a left mandibular central incisor in the same software program. All resulting digital crown designs were exported to STL files to assess crown margin accuracy at the coupling interface by superimposition with the control STL file of the scan body designed for the same abutment by the manufacturer. For this purpose, a CAD software program was used to automatically calculate median, minimum, and maximum deviations of margins in millimeters. Statistically significant pairwise differences among groups and between observers were assessed with the Wilcoxon signed-rank test (α=.05). ResultsFor the CAD professional, median deviations between designed crown STL files and the control STL of the scan body were 0.08 mm (range: 0.04 to 0.15) for group GOS; 0.10 mm (range: 0.06 to 0.18) for group GIS; and 0.05 mm (range: 0.03 to 0.08) for group IS. For the clinician, median deviations were 0.08 mm (range: 0.04 to 0.12) for group GOS; 0.11 mm (range: 0.07 to 0.17) for group GIS; and 0.05 mm (range: 0.04 to 0.11) for group IS. There were no significant differences between observers (P>.05). However, statistically significant differences were found between group IS and the other 2 groups (P=.001) but not between groups GOS and GIS (P>.05). ConclusionsThe present findings suggest that a digital wax pattern made with a dental CAD software program is not affected by varying levels of expertise but might be affected by subgingival margins.

Influence of Gingival Contour on Marginal Fit of CAD-CAM Zirconia Copings on Implant Stock Abutments.

Intraoral scanning subgingival finish lines has been described as challenging. The purpose of this study was to assess the impact of gingival contour around margins of implant stock abutments on marginal fit of Computer-aided Design - Computer-aided Manufacturing (CAD-CAM) zirconia copings. This in-vitro study was conducted on 40 analogues of implant stock abutments that were embedded into individual phantoms composed by a resin block. All 40 phantoms underwent two intraoral scans - one with (test group) and one without artificial gingiva (control group) - using a closed system intraoral scanner. Zirconia copings were then digitally designed and milled, followed by high-speed sintering, before being analyzed for marginal adaptation and internal surface roughness with scanning electron microscopy. Statistically significant differences between groups were assessed with the Mann-Whitney test. Median marginal gap values were 149.78 μm (95% CI: 112.39-216.66) for the test group and 94.90 μm (95% CI: 83.89-107.74) for the control group. A statistically significant difference was found between groups (p=0.0001). However, there were no subjective differences between groups for internal surface roughness. Within the limitations of this study, the present findings suggest that a gingival contour one millimeter higher than the finishing line affects marginal adaptation of CAD-CAM zirconia copings.

Comparison of strains for new generation CAD-CAM implant-supported crowns under loading.

The behavior of implant-crowns fabricated from recently introduced CAD-CAM zirconia-reinforced lithium silicate ceramic (ZLS) or a hybrid ceramic containing resin-reinforced glass network (HC) for strains around the implant platform is not well-known. A force absorption capacity of the latter has been claimed by the manufacturer. The aim of this study was to measure and compare recently introduced ZLS and HC with commonly used CAD-CAM implant crown materials for strain distribution around the implant platform. Four implants (Legacy 1; Implant Direct) were placed into a resin block. Zirconia abutments (Straight contoured stock abutment; Implant Direct) were torqued into the implant fixtures to support crowns that were milled from a virtual design using four different CAD-CAM materials (Vita Suprinity PC (ZLS), Vita Enamix (HC), IPS Emax, ZirCAD Zirkonzahn) (N = 20). The crowns were cemented with a resin cement, loaded and strain values were recorded. Three-dimensional digital image correlation (3D-DIC) was used to measure compressive and tensile strains around the implant platforms. The tensile and compressive strains were recorded for each test and first analyzed for equality of variance using Levene's test, and further tested using a 2-way ANOVA repeated measures analysis of variance (α = .05). The data analysis showed no statistically significant effect of crown material on the generated strains (P > .05). Compressive strains were significantly higher than the tensile strains (P < .05). One of the HC crowns fractured during loading. Strains generated around implant platform when new generation CAD-CAM crown materials were used was similar to strains observed when CAD-CAM zirconia and lithium disilicate crowns were used. New generation crown materials did not have a significant load absorption effect to change or minimize the strains generated around the implant platform.

Accuracy of Scanned Stock Abutments Using Different Intraoral Scanners: An In Vitro Study.

To determine the accuracy of a digital manufacturing method for dental implant restorations on stock abutments using intraoral scanners and prefabricated stock-abutment libraries. Two dental implants with internal hexagonal connections were placed in the mandibular second premolar and second molar areas of a partially edentulous dentoform model; stock abutments with a diameter of 5 mm, abutment height of 5.5 mm, and gingival cuff height of 2 mm were connected. The study model was scanned 10 times using a reference tabletop scanner and 5 types of intraoral scanners (IOSs). The data collected by 5 types of IOSs were divided into 3 groups, based on the type and matching of stock abutment library data: no library, optical library, and contact library groups. A total of 160 data files were analyzed, including reference data. The resulting data were used to evaluate trueness and precision. Trueness and precision values in the group in which library data of the stock abutment were not used were 42.0 to 76.3 µm and 30.5 to 99.7 µm; corresponding values when the library data using an optical scanner were matched were 51.2 to 73.4 µm and 26.3 to 62.8 µm, and those when contact scanner library data were used were 30.1 to 62.4 µm and 15.5 to 55.9 µm. Thus, the accuracy of the contact library group was significantly higher than the accuracies of the no library (p < 0.001) and optical library groups (p < 0.001). The application of prefabricated library data of stock abutments using a contact scanner improved the accuracy of scan data. Scan accuracy of the stock abutments differed significantly based on the type of scanner.

Cement shield membrane technique to minimize residual cement on implant crowns: A dental technique

Residual cement around implant crowns can cause peri-implant disease, which can be minimized by precementing on a copy abutment. This article describes the use of polytetrafluoroethylene (PTFE) tape to allow an intraorally delivered custom or stock abutment to act similar to a copy abutment. It requires minimal change to the restorative dentist's routine and helps minimize the risk of cement-induced peri-implant disease.

Effect of manufacturing techniques on the marginal and internal fit of cobalt-chromium implant-supported multiunit frameworks

Statement of problemSubtractive and additive computer-aided design and computer-aided manufacturing (CAD-CAM) systems have been used in the fabrication of cobalt-chromium (Co-Cr) long-span restorations. However, the accuracy of fit of multiunit frameworks is unclear. PurposeThe purpose of this in vitro study was to compare the marginal and internal fit of implant-supported, cement-retained 3-unit, 4-unit, and 5-unit Co-Cr metal frameworks fabricated by the lost wax (LW), CAD-CAM milling, and selective laser melting (SLM) techniques. Material and methodsA total of 90 Co-Cr metal frameworks were fabricated for 3-unit, 4-unit, or 5-unit implant-supported cement-retained restorations on stock abutments with 3 different manufacturing technique subgroups (LW, CAD-CAM milling, and SLM). The silicone replica technique was used to evaluate the marginal and internal discrepancy values. By using a light microscope at ×45 magnification and a digital measurement program, the thickness of the silicone layer was measured at 16 reference points on each abutment for a total of 3360 measurements. The effect of manufacturing techniques and number of units (groups) on discrepancy values was evaluated using a full factorial ANOVA model. Group and manufacturing technique effects were analyzed separately by 1-way ANOVA in case of significant interactions. Pairwise comparisons were evaluated using the Tukey post hoc test (α=.05). ResultsThe mean marginal discrepancy of 3-unit frameworks showed no statistically significant differences in the LW (35 μm) and SLM (25 μm) techniques; however, the frameworks manufactured by CAD-CAM milling (68 μm) had the highest marginal discrepancy values (P<.001). The mean marginal discrepancy values were 40 μm (LW), 33 μm (CAD-CAM milling), and 25 μm (SLM) for 4-unit frameworks, and no significant differences were found among the manufacturing techniques. For 5-unit frameworks, CAD-CAM milling techniques had the widest mean marginal discrepancy values (85 μm), and copings manufactured by the LW technique had the lowest mean marginal discrepancy values (36 μm). For all manufacturing techniques, axial discrepancy values were not affected with respect to the unit number (P=.526). The highest internal discrepancy values were measured at the occlusal area in all groups. ConclusionsCAD-CAM milling had the poorest marginal fit values for 5-unit frameworks, whereas the LW technique demonstrated the best results. Unit number had no significant influence on the marginal and internal fit of the LW manufactured frameworks.

CAD/CAM Custom Abutments for Esthetic Anterior Implant-Supported Restoration: Materials and Design

The purpose of this review is to discuss the use of computer-aided design and computer-aided manufacturing (CAD/CAM) custom abutments in the anterior region with a focus on abutment design and material selection. Advantages, disadvantages, and complications of CAD/CAM abutments are also considered. CAD/CAM abutments are available in various materials and with different connection platforms to the implant in order to meet esthetic, functional, and biological demands. Use of CAD/CAM concepts in the fabrication of custom abutments allows for definite advantages over both stock abutments and conventional cast custom abutments. CAD/CAM technology should be considered when restoring dental implants in the esthetic zone.

Interproximal papilla stability around cad‐cam and stock abutments in anterior regions: 2‐year prospective study

Interproximal papilla stability around cad‐cam and stock abutments in anterior regions: 2‐year prospective study

Comparing the Fracture Resistance of Alternatively Engineered Zirconia Abutments with Original Equipment Manufactured Abutments with Different Implant Connection Designs.

Aftermarket computer-aided design/computer-assisted manufacture (CAD/CAM) milled zirconia (Zr) abutments were recently introduced with minimal independent research regarding their fracture resistance. Third-party manufacturers often alter the original equipment manufacturers' (OEM) design with unknown effects on fracture resistance. These alterations include elimination of the titanium insert with subsequent introduction of Zr into the implant, changes to connection designs and shapes, and/or alterations to prosthetic screw design. This in vitro study compares the static load fracture resistance and mode of failure of alternatively engineered Zr abutments with those of prefabricated (OEM) Zr abutments with internal, external, and conical connections. Twenty Zr stock abutments (five per group) from OEMs were selected to demonstrate fracture resistance of external hex, internal connection, and conical connection implant designs (control groups). Atlantis abutments (Dentsply) (test group) were manufactured by means of CAD/CAM to match the OEM abutments (control groups). All samples had full-coverage all-ceramic crowns luted to the abutments. Static load fracture resistance was evaluated with an Instron test device. Modes of abutment failure were evaluated using both light and scanning electron microscopy. A Welch two-sample t test evaluated the OEM control groups vs the Atlantis test groups. Static load to failure (N) for each representative control group vs test group revealed (1) conical design OEM (387 N) vs Atlantis (211 N) (P < .011), (2) external-hex OEM (408 N) vs Atlantis (218 N) (P < .035), (3) trilobe internal connection OEM (430 N) vs Atlantis (260 N) (P < .014), and (4) internal connection OEM (448 N) vs Atlantis (244 N) (P < .02). Atlantis CAD/CAM Zr abutments demonstrated static fracture loads lower than those of their OEM counterparts. Failure modes were Zr fractures in the conical and external hex groups. The internal connection groups demonstrated a mixed mode of failure, with screw head fracture 100% of the failures in the internal Zr connection group. The trilobe internal connection group exhibited screw-head fracture in two of five samples and Zr fracture in the remaining three samples. Clinicians should consider avoiding the alternatively engineered Atlantis Zr abutment for restoration of posterior single teeth in cases in which occlusal forces may exceed 350 to 400 N.

Simplified digital workflow for dental implant restoration on a stock abutment using an intraoral scanner: A dental technique

A straightforward digital restorative method based on a library of stock abutments is presented. Precisely scanned data of laboratory analog components of the stock abutment were obtained using a tabletop scanner to produce the library. The stock abutment and surrounding teeth, opposing arch, and occlusal information were recorded using an intraoral scanner. After transferring the scanned data to computer-aided design software, an appropriate library file for the abutment connected within the mouth was matched in order to design the prosthesis.

Managing a fractured one-piece zirconia abutment with a modified plastic periodontal probe: A clinical report

This clinical report describes the management of a fractured 1-piece zirconia stock abutment from an implant with an internal connection using a modified plastic periodontal probe. This minimally invasive approach allows for the retrieval of fractured prosthetic components without causing irreversible damage to the implant’s platform or its internal threads and does not require special equipment or costly instruments.

Clinical Bonding of Resin Nano Ceramic Restorations to Zirconia Abutments: A Case Series within a Randomized Clinical Trial.

New dental materials are introduced and promoted in the field without extensive clinical testing. Using those materials in a clinical setting might result in unacceptable early failure rates. The purpose of this paper was to analyze bonding of a new dental restorative material to either zirconia stock abutments or zirconia customized abutments. Fifty participants seeking single implant treatment were included in a prospective study. Resin Nano Ceramic (RNC, Lava Ultimate, 3M ESPE, Seefeld, Germany) crowns were digitally manufactured and extraorally bonded to either a stock or a customized zirconia abutment (ZirDesign and ATLANTIS, DENTSPLY Implants, Mölndal, Sweden) by means of a resin composite cement (RelyX Ultimate in combination with Scotchbond Universal, 3M ESPE), strictly following the manufacturer's recommendations. The final restorations were screw-retained to the implants and followed during 12 months. Primary outcome parameter was uncompromised survival of the restoration, and secondary outcome parameter was mode of failure. No implants were lost. The uncompromised survival rate of the RNC crowns bonded to zirconia abutments after 1 year of clinical service was only 14% (n = 7). Catastrophic failure occurred in three cases (6%), whereas bonding failure between RNC crowns and zirconia abutments occurred in 80% of the cases (n = 40) within the first year of service. No statistical significant difference in uncompromised survival rate could be identified between abutment types (χ2 = 1.495, p = .209). Uncompromised survival rate after 1 year was highly significantly different (χ2 = 104.173, p < .001) from a reference standard, which was set at 95%. RNC crowns luted to stock and customized zirconia implant abutments with the particular resin composite cement in this trial have a poor prognosis, regardless of the abutment type used.