Types Of Abutments Research Articles

Esthetic Outcomes of Implant-Supported Single Crowns Related to Abutment Type and Material: A Systematic Review.

To systematically review the influence of abutment material and configuration on the soft tissue esthetic outcomes of implant-supported single crowns (iSCs) after 3 years. An electronic search on MEDLINE (PubMed) from January 2000 to July 2019 was conducted for clinical trials with no language restrictions. The focus question was: In partially edentulous patients with iSCs, does the abutment material (metal vs ceramic) or the configuration (standardized vs customized) have an effect on the soft tissue esthetic outcomes? Randomized controlled trials, controlled clinical trials, and prospective or retrospective case series with at least 10 patients and a minimum of 3 years of follow-up were included. The esthetic outcomes Pink Esthetic Score (PES), PES/White Esthetic Score (WES; ie, modPES), Papilla Index (PI), soft tissue recession, and papilla height change were extracted. Meta-analysis was performed when applicable. Of the 6,399 titles identified, 27 studies were included. Combined mean PES/modPES scores, translated into a scale of 0 to 100, were 68.8 for ceramic, 74.2 for metal (P = .392), 71.9 for customized, and 71.3 for standard (P = .981) abutments. Mean soft tissue recession was also similar between the abutment groups, abutment material (P = .850), and configuration (P = .849), ranging from -1.09 mm to +0.59 mm gain. Papilla height changes ranged from -1.22 mm to +1.0 mm gain. The reported mean PI was 2.16 for customized, 2.06 for standard (P = .552), 2.01 for ceramic, and 2.28 for metallic (P = .04) abutments. This systematic review showed that the abutment material and configuration had minimal impact on the evaluated soft tissue esthetic outcomes. Future research focusing on the included parameters in a randomized controlled manner is needed to validate the present findings.

Fracture Resistance of Zirconia, Polyetheretherketone, and Polyetherketoneketone Implant Abutments After Aging.

This study aimed to assess the fracture resistance of zirconia (Zr), reinforced polyetheretherketone (PEEK), and polyetherketoneketone (PEKK) implant abutments restored with glass-ceramic crowns after thermomechanical aging. Zr, reinforced PEEK, and PEKK titanium base abutments were divided into three groups (n = 10). CAD/CAM maxillary central incisor crowns were fabricated using monolithic lithium disilicate and luted to the abutments using resin cement. The specimens were thermomechanically aged (1.2 × 106 cycles, 49 N, 5°C to 55°C). After testing fracture strength and determining fracture patterns, statistical analyses were made using the one-way analysis of variance (ANOVA) and Tukey post hoc tests (α = .05). Fracture resistance of the PEKK abutments (541.90 ± 68.49 N) was significantly lower than the Zr (780.65 ± 105.77 N) and reinforced PEEK (741.09 ± 99.84 N) abutments (P = .000). A significant discrepancy was not detected between the reinforced PEEK and Zr abutments. Failures usually formed due to crown or abutment fracture, plastic deformation of the titanium base or screw fracture in the Zr group, crown fracture or separation of the abutment-crown complex from the titanium base in the reinforced PEEK group, and abutment fracture without crown deformation in the PEKK group. After thermomechanical aging, the reinforced PEEK abutments exhibited similar fracture resistance to the Zr abutments. All abutment types withstood the physiologic occlusal forces typical for the oral anterior region. Before considering them as alternative esthetic implant abutment materials, further in vitro and clinical studies are needed to determine their long-term performance.

Bonding Durability Between Zirconia and Different Types of Tooth or Implant Abutments—A Systematic Review. Part I: Outcomes of In Vitro Studies

To systematically review all in vitro studies focusing on the durability of different bonding protocols applied to zirconia restorations with different types of tooth or implant abutments. English-language articles published in dental journals up to March 2020 were searched using a combination of free text words and MeSH terms, as follows: zirconia; Y-TZP; zirconium; zirconia restoration; enamel; dentin; titanium abutment; titanium base; ceramic abutment; dental core; ceramic or metal post and core; composite build-up; bonding; adhesive cement; resin cement; adhesion; cementation; test; material testing; laboratory; and in vitro. Studies were identified for review based on certain inclusion and exclusion criteria. A total of 3,339 titles were identified. After a successive filtering process, a final total of 28 studies were included. The included studies featured different types of surface pretreatment methods, primers, resin cements, tooth and implant abutments, laboratory test outcomes, and designs. The relatively limited number of the identified studies and the heterogeneity of the extracted data did not allow for meta-analysis. Zirconia surface pretreatment is an essential step in the bonding protocol. Airborne-particle abrasion surface pretreatment had a positive influence on zirconia resin bonding to most types of tooth and implant abutments identified. Chemically activating the treated zirconia surfaces with an MDP monomer-based primer, along with an MDP monomer or phosphate ester monomer-based resin cement, seems to be a durable bonding protocol. Type of resin cement seems to be a less influential factor.

Cervical tooth anatomy considerations for prefabricated anatomic healing abutment design: A mathematical formulation

Statement of problemA custom emergence profile offers the ideal horizontal dimensions for an anatomic healing abutment. However, developing such an emergence profile can be a time-consuming and complex process. PurposeThe purpose of this study was to develop a mathematical formula defining horizontal cervical tooth geometry to design prefabricated, tooth-specific, healing abutments. Material and methodsCone beam computed tomography (CBCT) horizontal cross sections of 989 teeth on 54 participants were measured. For anterior and premolar teeth, 2 perpendicular ellipses were fitted onto the cervical tooth cross section that was defined by 3 parameters. The lingual ellipse followed the lingual outline of the tooth, and its diameter was the largest mesiodistal diameter of the tooth (parameter “a”); its buccolingual radius became parameter “b.” The buccal ellipse was perpendicular to the lingual ellipse and followed the buccal outline of the tooth. The buccolingual radius of the smaller ellipse became parameter “c.” For molars, the first ellipses followed the mesial outline of the tooth, and its larger diameter (parameter “a”) matched the largest buccolingual diameter of the tooth. Its smaller radius became parameter “h1.” The second ellipse was parallel to the first ellipse and followed the distal outline of the tooth. Its larger diameter became parameter “b”, and its mesiodistal diameter became parameter “h2”. Statistical differences between parameters were evaluated by the linear mixed model (α=.05 after Bonferroni adjustment). Pairwise comparisons were made separately for each parameter of the molars and separately for each parameter for the anterior teeth plus premolars. Teeth were put into the same parameter cluster if no significant differences were found between them for a specific parameter. If neither parameter (4 for molars and 3 for the other teeth) was different for 2 teeth, they were put into the same abutment cluster. The abutment clusters determined the type of anatomic healing abutment. The areas were calculated from the developed mathematical formula by using the parameters. In addition, cervical areas of 106 randomly chosen teeth were measured directly with a photo-editing software program. A computer algorithm was used to select 5 CBCT scans from the 54 by using the simple randomization method. The agreement between the 2 methods was evaluated by Bland-Altman analysis. ResultsThe lower and upper limits of agreement between the 2 methods were -8.57 and 7.36 mm2, respectively, with no bias (-0.61 mm2, P=.224). Significant differences were found between most parameters among the 14 tooth types (P<.001). Based on the parameters, 12 specifically distinct clusters were defined. Two tooth types were pooled into 1 abutment cluster: the maxillary first and second premolars and the mandibular first and second molars. ConclusionsThe cervical tooth cross section can be accurately defined by combining 2 elliptical elements. A comprehensive array of tooth specific emergence profiles can be provided by just 12 different prefabricated abutments, designed as per the recommended parameters.

Implant-prosthetic Rehabilitation with and without Platform Switching: A Retrospective Clinical Cohort Study

The study aimed to retrospectively compare peri-implant bone loss, prosthetic complications, and patient-reported outcome measures (PROMs) after implant-prosthetic treatment on abutments with platform switch or platform match. Records of patients, who received implant-prosthetic treatment on abutments with/without platform switch in a single dental clinic between November 2015 and November 2018, were retrospectively analyzed. Analysis was restricted to the following patient selection criteria: no need for any bone grafting procedures before/during implant placement, and no serious systemic disease. Implants were conventionally loaded with screwed prosthetic restorations after a healing period of 3 months. Crestal bone loss was measured by digital radiography at implant placement and after at least 2 years under functional implant loading conditions. Patient satisfaction was recorded with the visual analogue scale (VAS) at the time of the follow-up examination. Clinical records of 59 patients were available for analysis. Patients of the study cohort received in total 128 implants with different lengths and diameters according to the manufacturer's specifications. Prosthetic restorations were fixed either on abutments with platform switch (BEGO PS-UNI: n = 74; 57.8%) or platform match (BEGO SUB-TEC Universal: n = 54; 42.2%). No implant was lost and no failure of prosthetic restoration was recorded during follow-up, except for prosthetic screw loosening in 32 implants (25.0%). Abutment type and location (maxilla vs mandible) had a significant impact on peri-implant bone loss (OR = 3.4; 2.8). A significant reduced rate of bone loss was observed at implant sites, provided with abutments according to the platform switch concept (35.1 vs 64.8%). No significant correlation was recorded between less bone loss and a higher patient satisfaction, while loosening of the prosthetic screw was significantly associated with lower satisfaction scores. BEGO PS-UNI abutments with a platform switch design revealed significant less crestal bone loss after a mean observation period of 20.8 months. Abutments with a platform switch design may lead to less peri-implant bone loss. In order to maintain a higher patient satisfaction, clinicians should focus on the quality of the implant-prosthetic connection in screwed restorations.

PERSONALIZED CHOICE OF STRUCTURAL MATERIALS FOR ARTIFICIAL CROWNS FROM THE LEVEL OF MULTI-UNIT ABUTMENT OR TITANIUM PLATFORM FOR DIRECT PROSTHETICS ON DENTAL IMPLANTS

The high prevalence of secondary adentia in the adult population, as well as increased aesthetic requirements of patients has contributed to the development of orthopedic dentistry. Direct prosthetics on dental implants have been increasingly used for replacing defects in the dentition. However, the choice of structural materials for dental implant-supported prostheses is not fully understood. Hence, it remains a debatable issue.&#x0D; Purpose of the study: to justify the optimal structural materials for artificial crowns from the level of a multi-unit abutment or a standard titanium platform for direct prosthetics on dental implants with the use of finite-element analysis of the stress-strain state of the “bone tissue-dental implant-abutment-suprastructure” multidimensional model under the conditions of simulation modeling.&#x0D; Materials and methods. Specialized CAD / CAE software was employed to develop multi-dimensional computer models of biomechanical systems such as “bone tissue-dental implant-abutment-suprastructure” with simulation of direct prostheses on dental implants with the corresponding physical and mechanical properties of structural elements and load conditions. The created 10 simulation models were based on combinations of two types of abutment (standard titanium platform (A1) and multi-unit abutment (A2)), and five structural materials of the crown, including lithium disilicate glass ceramic (KM1), polymer-infiltrated hybrid ceramic (KM2), polymethyl methacrylate (PMMA) (KM3), zirconia (KM4), and multi-layer zirconia (KM5)). The stress-strain state and the bearing capacity of biomechanical systems were assessed with the use of the von Mises stresses analysis and safety factors.&#x0D; Results. During a numerical experiment, there was revealed a complex stress-strain state in “bone tissue - dental implant - abutment - suprastructure” biomechanical systems. The maximum loads were recorded in systems with A1 and A2 type of abutment in the crown models (149.37 MPa and 142.08 MPa, respectively), spongy (4.25 MPa and 4.08 MPa) and the cortical bone (20.58 MPa and 20.61 MPa). The nature of the distribution of the von Mises stresses in the structural elements of systems with A1 and A2 types of abutments was found to be similar for all models under consideration with KM1, KM2, KM4, KM5 structural materials of crowns, except for the system with KM3 suprastructure material.&#x0D; Conclusions. Based on the findings of computer simulation of the stress-strain state of “bone tissue - dental implant - abutment - suprastructure” biomechanical systems, there have been grounded the optimal structural materials for dental implant-supported crowns for direct prosthetics by such abutment as a standard titanium platform and multi-unit abutment. The obtained values of the von Mises stresses analysis and safety factors showed that with external force applied to the dental implant-supported crown the at an angle of 11.5°, the greatest bearing capacity was ensured by biomechanical systems with a standard titanium platform and multi-unit abutment with crown materials including zirconia (safety factors 6.22 and 6.42 respectively), multilayer zirconia (safety factors 5.52 and 5.70) and lithium disilicate glass ceramic (safety factors 2.39 and 2.52).

Comparison of stress distribution on dental implant with different abutment types

Dental implants have a triumph pace of 90–98%, which in clinical terms is essentially high. Implant failure may occur at earlier or later stage. In assessment of the drawn-out accomplishment of a dental implant, the reliability and the stability of the implant–abutment play a vital role. In general, the achievement of the treatment relies upon numerous factors influencing the implant, implant–abutment and abutment–prosthesis interfaces. Early implant failure occurs due to the improper mechanical stability. This study researches the stress distribution in an implant with different implant abutments with different height and angle in different loading criteria. The abutment heights are 5.50 mm, 3.50 mm and 3.60 mm respectively. The loading conditions are applied in vertical and 30˚ angle with the value of 36 N & 100 N. Cobalt chromium alloy is used which has the superior properties like high stiffness, tightly polished, wear resistant and also it is used to avoid crevice corrosion. Computational models of abutment types with different heights were modeled using CAD software and Analyzed with FEA software for finding out the total deformation, Maximum principle stress, and Maximum shear stress. Based on the structure of a dental implant system, it gives significant performance. The minimum and maximum total deformation, Maximum principle stress, and Maximum shear stress were noted in the Type 3 under 36 N vertical condition and Type 1 under 100 N under 30˚ respectively.

Evaluation of the Mechanical Reliability of Different Implant-Abutment Connections for Single Crowns According to the ISO 14801 Fatigue Test Protocol.

The aim of this in vitro study was to evaluate the mechanical behavior regarding dynamic fatigue of different implant-abutment connections and the unitary indication of abutments for all regions of the mouth. This experimental study developed according to international standards (ISO 14801:2007) was performed using five types of implants and abutments: G1-external hex smart implant and 17-degree universal abutment (EHS); G2-cortical external hex implant and 17-degree universal abutment (EHTi); G3-internal hex implant and 30-degree universal abutment (IH); G4-Morse taper implant (11.5 degrees) and 17-degree universal abutment (MT11.5); and G5- Morse taper implant (16 degrees) and 30-degree universal abutment (MT16). A 15-Hz cyclic loading was applied to the specimens with the maximum number of cycles set at 5 × 106. Success was defined when three samples supported 5 million cycles without failure. The maximum load supported from each group after dynamic loading was recorded. The Spearman correlation and the Lowess method were used to analyze the correlation between the number of cycles and the applied load, and the Kruskal-Wallis and Nemenyi tests were used for comparison between the abutments when reaching 5 million cycles. There was a negative correlation (r < 0.00) and significant difference (P < .05) between the number of cycles and the load for each type of implant and abutment. The load values supported by each group after cyclic loading to achieve 5 million cycles were as follows: EHS, 225 N; EHTi, 215 N; IH, 220 N; MT11.5, 210 N; and MT16, 240 N. The MT16 implant-abutment assembly presented a significantly higher load (P = .024) than the MT11.5 implant-abutment assembly. All implant-abutment connections investigated in this study resisted average occlusal force values reported as acceptable in the literature and may be indicated for any region of the mouth.

Reabilitação dentária em região anterior com implante imediato e reconstrução alveolar por meio de enxertos conjuntivo autógeno e ósseo xenógeno

The immediate implant, in addition to provide reduction of clinical treatment time, aims to promote preservation of marginal bone ridges and maintain the emergency profile of the dental crown. The present study shows a clinical procedure involving minimally traumatic extration, followed by the immediate installation of a morse taper implant (Alvim 3,5 x 13 mm, Neodent®) in addition to the use of subepithelial connective tissue graft (SCTG). In order to remedy a loss of remnant alveolar bone tissue, bovine biomaterial (Geistlich Bio-Oss®) was used in alveolar reconstruction also with the intention of covering implant’s spires and promoving stability for the recently grafted soft tissue. After the surgical installation of the implant was completed, an initial 30N locking was obtained, what made impossible the immediate installation of a provisional over the implant. Then fixed temporary restoration was carried out, using a pontic with cervical ovoid format to maintain height, emergency profile, and interdental papilla contour. After 4 months of postoperative, was carried out surgery of implant reopening, with a new graft of connective tissue using the technique called pediculated, aiming the gain of vestibular tissue volume. Universal abutment type prosthetic component morse taper was used (measuring 3,3 x 4 x 6,5 mm Neodent®) and was carried out the confection and cementation of implant supported provisional. After a few weeks, the definitive crown was installed. With those procedures, for proper planning, and highly regarded techniques, a highly satisfactory functional and aesthetic result could be obtained.

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.

Fracture strength of various titanium-based, CAD-CAM and PFM implant crowns.

CAD-CAM has dramatically advanced dental restorative procedures to include implant-supported crowns. The purpose of this study was to compare the fracture resistance following mechanical loading and thermocycling of various screw-retained and cement-retained ceramic and polymethylmethacrylate material combinations using the TiBase abutment compared to PFM implant-supported crowns. Twelve implant restorations were fabricated for each of eight groups. Three groups were screw-retained and five groups were cement-retained implant restorations. The ceramic and polymethylmethacrylate restorations were fabricated on the TiBase abutment while the PFM restorations were fabricated on an UCLA abutment. Data were analyzed with a one way Analysis of Variance and Tukey's post-hoc test to evaluate the effect of abutment and crown type on fracture load (alpha = 0.05). A significant difference was found in the maximum fracture load between groups (P < 0.001). The screw-retained implant restorations demonstrated higher fracture loads than their cement-retained counterparts. The TiBase abutment compared favorably to the UCLA abutment. The TiBase abutment is a titanium insert which combines the esthetics of a ceramic abutment with the mechanical properties of a titanium abutment and should be considered a viable clinical alternative to the conventional implant-supported PFM crown based on theses in vitro results and in context of in vivo studies. The lithium disilicate hybrid abutment/crown implant-supported restoration utilizing the TiBase abutment may be an ideal clinical choice due to simplicity, single appointment CAD-CAM, and esthetics.

Radiographic Assessment of Accuracy of Fit for Different Conical Connection Abutments on Tapered Implants

Purpose: This study aimed to evaluate the accuracy of fit between implant and abutment using different types of abutments. Methods: A total of 32 titanium implants with 3.5mm diameter, 12mm length and conical connection were used in this study. All implants were randomly divided into four equal groups according to the type of the abutment used as follows: Group I (Control Group): Ready-made Titanium abutment . Group II: Custom-made Gold abutment . Group III: Custom-made Co-Cr abutment with prefabricated machined Co-Cr base . Group IV: Custom-made Fully Casted Co-Cr abutment. Abutments for groups II, III, IV were fabricated using the conventional casting technique to obtain custom-made gold abutments for group II and custom-made Co-Cr abutments for groups III, IV. All the abutments were tightened at 35 N/cm using manual Torque Wrench. The x-ray sensor was placed parallel to the implant and a radiograph was taken for each sample. The distance from the end of the base of the abutment till the beginning of the screw holes of the implant was measured in mm. Data were statistically studied. Results: Results showed that Group IV had the statistically significantly highest mean value. Group III showed statistically significantly lower mean value. There was no statistically significant difference between Group I and Group II; both showed statistically significantly lowest mean values. Conclusions: Within the limitations of this study, it was concluded that: Custom-made Co-Cr abutments with prefabricated Co-Cr base revealed promising results. Casted connections don’t seem to be a good alternative to machined connections.

Effect of Anti‐Rotational Abutment Features and Novel Computerized Fabrication Techniques on the Marginal Fit of Implant‐Supported Metal Copings

An in vitro study to compare the marginal fit of cobalt-chromium (Co-Cr) metal copings fabricated with selective laser melting (SLM), computer-aided design and computer-aided manufacturing (CAD/CAM) milling, and lost-wax (LW) techniques, on abutments with two different antirotational features. A total of 60 stainless steel abutments with the same length and convergence angles were fabricated using a numerical control machining. Half of the abutments had one flat plane, while the other half had three grooves as an antirotation feature. Thirty abutments of each kind were then divided into three subgroups, and metal copings were fabricated with SLM, CAD/CAM milling, or the LW technique (n = 10). The metal copings were cemented with polycarboxylate cement. Marginal gap measurements were performed using a stereomicroscope at a magnification of × 45 and data were analyzed with two-way analysis of variance (ANOVA) tests. The LW (p = 0.002) and CAD/CAM (p < 0.001) techniques exhibited increased marginal gaps on the abutments with a three groove antirotational feature; however, no significant difference was detected with the SLM technique (p = 0.259). The copings fabricated with the SLM technique demonstrated significantly lower gap values in both abutment types (p < 0.001). While all marginal gap values were within the clinically acceptable range (<120 µm), abutments with more antirotational grooves exhibited wider marginal gaps with the LW and CAD/CAM techniques.

Effective microbiological decontamination of dental healing abutments colonised with Rothia aeria by a diode laser as a helpful step towards successful implantoprosthetic therapy.

The aim of the study was to find variant of diode laser (λ = 810 nm) irradiation, which ensures elimination of unwanted microorganisms, including Rothia aeria, from dental healing abutments, and consequently accelerates process of wound healing in implantologically treated patients. The scope of the study included identification of the most contaminated areas on healing abutments, identification of microorganisms inhabiting various environments of oral cavities, assessment of effectiveness of various laser decontamination parameters against detected microorganisms (preliminary studies) and assessment of wound healing in patients after applying abutments with low roughness and optimal variant of laser irradiation (clinical studies). Imaging of surfaces of the healing abutments was performed using vertical scanning interferometry, scanning electron microscopy and optical microscopy. Microorganisms inhabiting the healing abutments, teeth and saliva from tested patients were identified using matrix-assisted laser desorption/ionisation time-of-flight mass spectrometry. Three programmes of near-infrared diode laser at average powers of 1.00-3.84 W with two variants of exposure time were used for optimisation of laser parameters. Observation of wound healing was performed for 100 patients during 20 days after installation of abutments. On surfaces of the used healing abutments, a large number of microorganisms, with a predominance of R. aeria, were found. Irradiation with periimplantitis surgical programme for 30 s resulted in 99-100% reduction in the number of R. aeria and other microorganisms, depending on type of abutment (in vivo). The use of diode laser in the selected variant accelerates wound healing and provides complete elimination of pathogenic R. aeria and other microorganisms inhabiting surfaces of the healing abutments without marks.

Genomic Evaluation of Formed Biofilm on Dental Implants with Different Surface Treatments Associated with Zirconia or Titanium Abutments: An In Vitro Study.

The aim of this study was to evaluate the formed biofilm on two types of implant surfaces (hydrophilic or hydrophobic) associated with titanium (Ti) or zirconia (Zn) abutments. Samples were separated into four groups according to type of surface and abutment used (n = 10): (1) hydrophobic/Ti abutment, (2) hydrophilic/Ti abutment, (3) hydrophobic/Zn abutment, and (4) hydrophilic/Zn abutment. Implant-abutment assemblies were incubated with human saliva and supragingival biofilm. Samples of biofilm were evaluated by DNA Checkerboard hybridization, identifying up to 41 species. Scanning electron microscopy (SEM) images were obtained from the implants and abutments. The microbial count was higher for samples from groups with the hydrophilic/Ti abutment, followed by hydrophobic/Zn abutment, hydrophilic/Ti abutment, and hydrophobic/Zn abutment (P < .05). Hydrophilic surfaces and Zn abutments showed the highest counts of microorganisms. Individual bacterial counts were variable between groups; the hydrophilic/Zn abutment group had the highest microbial diversity, including T forsythia, P nigrescens, S oralis, S sanguinis, L casei, M orale, P aeruginosa, P endodontalis, S aureus, S gallolyticus, S mutans, S parasanguinis, S pneumoniae, and C albicans. The hydrophilic/Ti abutment group had the highest count of T forsythia and T denticola, microorganisms of Socransky red complex. The SEM images showed the bacterial colonization in both surfaces of the implant and abutment. Different surfaces of implants and abutments showed significant differences in the count and diversity of species. The hydrophilic/Zn abutment group presented the highest count and diversity of target species.

Influence of Implant Connection, Abutment Design and Screw Insertion Torque on Implant-Abutment Misfit.

Background: An accurate fit at the implant-abutment interface is an important factor to avoid biological and mechanical complications. The aim of this study was to evaluate the marginal misfit at the implant-abutment interface on external and Morse taper connection, with straight and angulated abutments under different insertion torque loads. Materials and Methods: A total of 120 implants were used, 60 with external connection (EC) and 60 with Morse taper connection (IC). Straight (SA) (n = 60) and angulated abutments (AA) (n = 60) were randomly screwed to each connection at different torque levels (n = 10 each): 10, 20 and 30 Ncm. All specimens were subjected to thermal and cyclic loading and the misfit was measured by scanning electron microscopy. Data were analyzed with one-way ANOVA, t-test and Kruskal-Wallis test. Results: Significant differences (p < 0.001) were found between connections and abutments regardless of the torque applied. Morse taper connections with straight and angulated abutments showed the lowest misfit values (0.6 µm). Misfit values decreased as torque increased. Conclusions: The misfit was affected by the type of connection. The type of abutment did not influence the fit in the Morse taper connection. The higher the tightening torque applied the increase in the fit of the implant-abutment interface.

Effect of Serrating Abutment-Implant Mating Surface on Torque Stability of Implant-Abutment Connection, Before and After Cyclic Loading

This study evaluated the effect of adding serration to the abutment-implant connection on torque maintenance before and after loading. Two implant systems with the same dimensions and connection design (internal 8° Morse taper octagon) were selected: one with nonserrated abutments (Simple line II) and the other one with serrated abutments (F & B). The removal torque value (RTV) was measured in 2 groups for each system: one group with one-piece abutments and the other group with 2-piece abutments, before and after cyclic loading (n = 10 in each group). The initial RTV of the abutment screw was measured with a digital torque meter. Each abutment received a cement-retained metal crown with 30° occlusal surface. Cyclic axial peak load of 75 ± 5 N was applied to the implants for 500 000 cycles at 1 Hz. The post-load RTV was then measured. Two-way and repeated-measures analysis of variance (ANOVA), and independent t test were applied to assess the effects of cyclic loading, connection design, abutment type, and their interaction on the percentage of torque loss (α = .05). Two-way ANOVA showed that serration of mating surfaces had a significant effect on torque maintenance before (P < .001) and after (P = .004) cyclic loading. Repeated-measures ANOVA also showed that loading had a significant effect on the torque loss percentage (P < .01). Comparison of the groups with t test showed that the torque loss of the serrated groups was lower than that of non- serrated groups. Despite the limitations of this study, the stability of the implant-abutment connection in the serrated design was higher than that of non-serrated group.

Comparing the Maximum Load Capacity and Modes of Failure of Original Equipment Manufactured and Aftermarket Titanium Abutments in Internal Hexagonal Implants

The purpose of this in vitro study is to compare the maximum load capacity and modes of failure under static loading in three types of titanium abutments (n = 3) with different processes or manufacturers. The Pre-Ti group consists of prefabricated titanium abutments from original equipment manufacturers (OEM), the CAD-Ti group consists of OEM titanium abutments fabricated with computer-assisted design/manufacturing (CAD/CAM) technique, and the AM-Ti group is CAD/CAM titanium abutment made by aftermarket manufacturers. A full zirconia crown was fabricated and cemented to each abutment. An all-electric dynamic test instrument was used to place loading on the zirconia crown with a crosshead speed set at 1 mm/min. The mean maximum load capacity of both OEM titanium abutments was significantly higher than the aftermarket titanium abutments. All these three types of implant–abutment complexes exhibited similar modes of failure, which included deformation of the abutment and implant, fracture of the abutment and retentive screw.

Internal and Marginal Fit and Fracture Strength of Narrow Diameter Dental Implant-Abutment Assembly.

The aim of this study was to assess the internal and vertical marginal fit of metallic copings to abutments and the fracture strength of different narrow diameter dental implant/abutments, either submitted to thermomechanical cycling or not. Sixty-four implant/abutments (n=16) were divided into 4 groups according to diameter and abutment type: G3.5-UAC (morse taper implant Ø3.5mm + universal abutment with beveled chamfer finish); G2.9-UAS (morse taper implant Ø2.9mm + universal abutment with shoulder finish); G2.8-AA (morse taper friction implant Ø2.8mm + anatomical abutment) and G2.5-HP (one-piece implant Ø2.5mm with indexed hexagonal platform). Each group was divided into two subgroups (n=8): submitted and not submitted to thermomechanical cycling (TMC). To assess internal and vertical marginal fit of metallic copings, the assemblies were scanned using microtomography (micro-CT) (n=5). The samples were subjected to the compressive strength test on a universal test machine. Group G3.5-UAC showed the highest marginal misfit regardless of TMC (p<0.05). All other groups were similar after TMC. Group G2.8-AA showed the lowest internal misfit both with and without TMC (p<0.05). Group G2.8-AA showed the highest fracture strength, similar only to G2.5-HP without TMC and G3.5-UAC with TMC. The type of abutment affects the internal and marginal fit of metallic copings and the anatomical abutment led to the best internal and marginal coping fit. The narrow diameter dental implant/abutments differ in terms of fracture strength, the strongest assembly was that composed by implant of type V grade titanium without internal threads (friction implant).

Influence of anodized titanium abutments on the esthetics of the peri-implant soft tissue: A clinical study

Statement of problemThe grayish appearance of a titanium abutment discolors the peri-implant soft tissue, especially if the gingiva is thin. Whether an anodized titanium abutment can prevent the discoloration is unclear. PurposeThe purpose of this clinical study was to investigate the color change of peri-implant soft tissue surrounding a titanium abutment that had been colored by anodic oxidation. Material and methodsCommercially available titanium abutments were anodized to form a gold and pink titanium abutment and formed the experimental groups. Unanodized titanium and zirconia abutment were used as the control groups. Four types of abutments were fabricated for each participant who received dental implants in the anterior maxilla. The abutments and corresponding definitive crowns were inserted, and the color of the peri-implant soft tissue and contralateral gingiva were measured with a spectrophotometer. The thickness of the peri-implant soft tissue was recorded after probing with an endodontic file. ResultsEleven participants were included in this study. The color differences caused by all tested abutments were higher than the critical threshold of ΔE=3.7. The mean color difference (ΔE), from low to high, was the zirconia, pink-anodized titanium, gold-anodized titanium, and unanodized titanium abutment; their values of (ΔE) were 6.81, 7.63, 7.90, and 8.74, respectively. The mean thickness of the peri-implant soft tissue was 2.41 ±0.52 mm. ConclusionsWithin the limitation of the small sample size in this study, the gold-anodized and pink-anodized titanium abutment achieved better esthetics for peri-implant soft tissue than the unanodized titanium abutment. Zirconia was the optimal abutment material for the esthetic region.