Ceramic Abutments Research Articles

Monolithic Hybrid Abutment Crowns (Screw-Retained) Versus Monolithic Hybrid Abutments With Monolithic Crowns (Adhesively Cemented): Three-Year Data of a Prospective Clinical Split-Mouth Study.

This study compares the restoration of single-tooth implants with screw-retained lithium-disilicate hybrid-abutment crowns and single-tooth lithium-disilicate crowns adhesively bonded to hybrid abutments with regard to objective clinical and subjective patient-specific evaluation criteria over a time of observation of 3 years. Two bone-level implants were placed in contralateral sides of the same jaw in 10 patients, each with two single-tooth gaps. After osseointegration, implants were uncovered and an impression was taken. In accordance with the split-mouth design, one implant in each patient was restored with a screw-retained hybrid abutment crown and the other implant with a hybrid abutment and an adhesively bonded single-tooth crown. The restorations were randomly allocated to the implants. Prefabricated titanium bases were used. The ceramic abutments and restorations were fabricated monolithically with pressed lithium-disilicate ceramic. An objective evaluation (survival, technical, or biological complications, FIPS) by the practitioner and a subjective evaluation (satisfaction, OHIP) by the patient were carried out after 3, 6, 12, 24, and 36 months after restoration placement. Both restoration types showed a survival rate of 100% after 3 years of observation. No technical or biological complications occurred. No significant difference was observed between the two types of restoration neither for objective (survival, technical or biological complications, FIPS) nor subjective (satisfaction, OHIP) evaluation criteria (p > 0.05). No statistically significant differences were observed between screw-retained and cemented pressed lithium-disilicate restorations on bone-level implants for both objective and subjective evaluation criteria, respectively. Monolithic hybrid-abutment crowns (screw-retained) and monolithic hybrid abutments with single-tooth crowns (cemented) made of pressed lithium disilicate can be used to successfully restore single implants.

Fracture resistance of hybrid ceramic abutments with different restoration lengths: A pilot study.

In this pilot study, the fracture resistance of hybrid abutments with different restoration lengths was investigated. Sixteen monolithic zirconia restorations of an upper right incisor were designed to fit a titanium base abutment. Eight central incisors had a crown length of 8 mm (T1) and the other half a length of 12 mm (T2). All crowns were cemented on the titanium base using a resin cement. After cementation, the samples were placed in a thermocycler for 5000 cycles. Fracture strength was measured using a universal test machine. Deformations and fractures of the samples were investigated. The mean fracture resistance of T1 was 515 N (SD 96 N, 339-650) and 305 N (SD 57 N, 234-408) for T2 (p < 0.001). Both groups showed deformation of the titanium base, with no significant difference between both groups (p = 0.200). A difference in fracture type (p = 0.013) was observed, with significantly more screw fractures occurring in group T1 (p = 0.026). Within the limitations of this study, hybrid restorations with standard titanium base abutments can withstand forces that have been associated with chewing, irrespective of the crown length. However, the shorter crowns demonstrated more fatal fractures.

Effect of cement type, luting protocol, and ceramic abutment material on the shade of cemented titanium-based lithium disilicate crowns and surrounding peri-implant soft tissue: a spectrophotometric analysis.

The objective of the study was to analyze the impact of cement, bonding pretreatment, and ceramic abutment material on the overall color results of CAD-CAM ceramic crowns bonded to titanium-based hybrid abutments. For single implant restoration of a maxillary lateral incisor a total of 51 CAD-CAM-fabricated monolithic lithium disilicate crowns were fabricated and subsequently bonded onto 24 lithium disilicate Ti-base abutments, 24 zirconia Ti-base abutments and 3 resin abutment replicas as a control group. The 48 copings were cemented with three definitive and one provisional cement on both grit-blasted and non-blasted Ti-bases. The color of each restoration and surrounding artificial gingiva was measured spectrophotometrically at predefined measuring points and the CIELAB (ΔEab) color scale values were recorded. The color outcome of ceramic crowns bonded to hybrid abutments and soft tissues was affected differently by cements of different brands. Grit-blasting of Ti-bases prior to cementing CAD-CAM copings affected the color results of all-ceramic crowns. There was a significant difference (P = .038) for the median ΔE value between blasted and non-blasted reconstructions at the cervical aspect of the crown. Full-ceramic crowns on zirconia Ti-base abutments exhibited significantly lower ΔE values below the threshold of visibility (ΔE 1.8). In all subcategories tested, the use of a highly opaque temporary cement demonstrated the lowest median ΔE for both the crown and the artificial gingiva. Various cements, core ceramic materials and airborne particle abrasion prior to bonding can adversely affect the color of Ti-base supported ceramic crowns and peri-implant soft tissue. However, zirconia CAD-CAM copings and an opaque cement can effectively mask this darkening.

Implant-supported single all-ceramic crowns made from prefabricated (stock) or individualized CAD/CAM zirconia abutments: A 5 year randomized clinical trial.

The aim of this randomized, prospective, and clinical multicenter study was to compare the overall clinical performance of two restorative options over a 5-year period: individualized CAD/CAM abutments veneered with a hand-layered ceramic, and prefabricated zirconium dioxide abutments veneered with press ceramic and inserted into a single edentulous gap in the anterior maxilla. Forty subjects were recruited from two universities: 20 from the University of XX and 20 from the University of XY. Each subject received an implant to restore a single edentulous gap in the maxillary anterior region (14-24 FDI). 20 patients were randomized into each Group. Group A received a one-piece single crown produced from a prefabricated zirconia abutment with pressed ceramic and Group B received an individualized CAD/CAM zirconia abutment with a hand-layered technique. After 5 years, the aesthetic and radiographic parameters were assessed. Group A had four dropouts and one failure, resulting in a 95% survival rate and 95% success rate. Group B had two dropouts and two failures which resulted in a 90% survival rate and 90% success rate. No crestal bone level changes were observed, with a mean DIB of 0.06 mm in Group A and 0.09 mm in Group B. No statistically significant differences were present at baseline, 6 months, 1 year, 3 years, or 5 years for DIB values between time points and groups. Pink aesthetic score/white aesthetic score, Peri-Implant and Crown Index, and Implant Crown Aesthetic Index values were stable over time at all five points for both groups. Both implant-supported restorative options represent a valuable treatment option for the restoration of implant crowns in the anterior maxilla. In general, the use of ceramic abutments in the anterior zone represents a valuable treatment procedure with both standardized and CAD/CAM individualized abutments and following the recommendations from the respective manufacturer(s).

Titanium Base Abutments in Implant Prosthodontics: A Literature Review.

Implant abutments are essential components in restoring dental implants. Titanium base abutments were introduced to overcome issues related to existing abutments, such as the unesthetic appearance of titanium abutments and the low fracture strength of ceramic abutments. This study aimed to comprehensively review studies addressing the mechanical and clinical behaviors of titanium base abutments. A search was performed on PubMed/MEDLINE, Web of Science, Google Scholar, and Scopus databases to find articles that were published in English until December 2020 and that addressed the review purpose. A total of 33 articles fulfilled the inclusion criteria and were included for data extraction and review. In vitro studies showed that titanium base abutments had high fracture strength, adequate retention values, particularly with resin cement, and good marginal and internal fit. Although the clinical assessment of titanium base abutments was limited, they showed comparable performance with conventional abutments in short-term evaluation, especially in the anterior and premolar areas. Titanium base abutments can be considered a feasible treatment option for restoring dental implants, but long-term clinical studies are required for a better assessment.

Optical Efficacy of Titanium Nitride-Coated Abutment Material on Soft Tissue Discoloration: A Spectrophotometric In Vitro Analysis.

The objective of this investigation was to assess the extent of mucosal discoloration caused by different CAD/CAM abutment materials and to determine the influence of mucosa thickness on the subsequent color, with a particular focus on titanium nitride. In a pig maxilla, a trapdoor-shaped mucosa flap was prepared unilaterally. Several CAD/CAM abutment materials were used to assess a number of clinical scenarios. Varying mucosa thicknesses were simulated by connective tissue grafts harvested at the contralateral side of the palate, resulting in layer thicknesses of 1.5, 2, and 3 mm. Titanium (Ti), zirconia (ZrO2), and titanium nitride (TiN) served as test specimens with and without ceramic veneering. Color differences (ΔE) and deviations in brightness (L), chroma (C), and hue (H) were determined spectrophotometrically, comparing the measured value of the native tissue and the results obtained with different materials at varying mucosa thicknesses. All tested specimens caused a mucosa discoloration in comparison to the native tissue, diminishing with increasing mucosa thickness. The use of TiN demonstrated the least mucosa discoloration in thin soft tissue of 1.5 mm, with a mean ΔE value of 1.93 (P = .004). While ZrO2 revealed a comparable ΔE value of 2.13 (P = .022) at a tissue thickness of 1.5 mm, Ti showed the highest mucosa discoloration above the visibility threshold of ΔE = 3.1, with a mean ΔE value of 4.07 (P = .002). Ceramic veneering of the Ti samples led to a considerable reduction in soft tissue discoloration, with a resulting ΔE value of 2.2. The veneering of TiN and ZrO2 samples with porcelain, on the other hand, had no noticeable effect on the mucosa color. CAD/CAM abutment materials cause an adverse soft tissue color shift that decreases with increasing mucosa thickness. In thin peri-implant mucosa, titanium nitride and zirconia lead to the least discoloration. Due to their positive optical properties and mechanical superiority compared with ceramic abutments, gold-hue titanium nitride-coated CAD/CAM abutments could be a clinical alternative in cases of thin peri-implant mucosa.

Biomechanical evaluation of 3-unit fixed partial dentures on monotype and two-piece zirconia dental implants

This study aimed to evaluate the biomechanical behavior, stress distributions and bone microstrain of fixed partial dentures (FPD) with ceramic abutments supported on monotype zirconia implants, titanium implants and two-piece zirconia implants, using finite element analysis. A three-dimensional model of the jaw was simulated containing 1.0 mm thick cortical bone and cancellous bone tissue. A FPD and implant models (4.1 x 10 mm) were modeled containing a cement-retained implant abutment. These models were replicated in three groups with similar geometries: Titanium Implant and Zirconia Abutment (Ti-Zr); Zirconia Implant and Zirconia Abutment (Zr-Zr) and Monotype Zirconia Implant (Zr-S). An axial load of 300 N was applied to the center of the first premolar. The microstrain (με) and the Von-Mises stress (MPa) were assumed as failures criteria. For the three groups, a higher stress concentration was observed in the region of FPD connectors. The Ti-Zr group showed a higher stress concentration in the prosthesis and implant when compared to the other groups. However, the smaller elastic modulus of the titanium implant, in relation to the zirconia, provided a lower stress in the abutment and in the prosthetic screw. The monotype implant system allowed a more homogeneous stress distribution and its strain were predominantly located in the cervical region of the peri-implant bone tissue. Monotype or two-piece zirconia implants can be used for rehabilitation with FPD. However, the absence of separation between implant and abutment in the monotype system avoids the stress concentration in the prosthetic screw and reduced the peri-implant bone strain.

Failure Load of Monolithic Lithium Disilicate Implant-Supported Single Crowns Bonded to Ti-base Abutments versus to Customized Ceramic Abutments after Fatigue.

This laboratory study analyzed the influence of retention mode (screw- vs cement retained) and fatigue application on the failure load of monolithic lithium-disilicate (LDS) implant-supported single crowns (ISSC). A total of 72 samples of monolithic LDS (*Ivoclar Vivadent) ISSC were divided into three groups (n = 24) according to their type of retention mode: Group Ti-CAD: Titanium base (SICvantage CAD/CAM Abutment red (SIC invent AG), screw-retained milled monolithic LDS (IPS e.max CAD*); Group Ti-P: Titanium base (SICvantage CAD/CAM Abutment red), screw-retained pressed monolithic LDS (IPS e.max Press*) and Group Ti-Cust: Titanium base with cemented press LDS (IPS e.max Press*) crown on a LDS (IPS e.max Press*) custom abutment. A mandibular first molar implant-supported single crown model was investigated (Titanium implant: SICvantage-max, SIC invent AG, diameter: 4.2 mm, length: 11.5 mm). Half of each group (n = 12) w​ere exposed to fatigue with cyclic mechanical loading (F = 198 N, 1.2 million cycles) and simultaneous thermocycling (5-55°C). Single load to failure testing was performed, before (Subgroups Ti-CAD, Ti-P, and Ti-Cust) and after (Subgroups Ti-CAD-F, Ti-P-F, and Ti-Cust-F) fatigue. Weibull distribution was used to determine the characteristic strength and Weibull modulus differences between groups. Probability of survival at 900N load was calculated. No samples failed during fatigue. Characteristic strength values were as follow: Ti-CAD: 3259.5N, Ti-CAD-F: 2926N, Ti-P: 2763N, Ti-P-F: 2841N, Ti-Cust: 2789N, Ti-Cust-F: 2194N. Whereas no difference was observed between pressed or milled monolithic crowns cemented to Ti-base, regardless of loading condition, fatigue decreased the characteristic strength of crowns cemented to custom abutments. Probability of survival at 900 N was not significantly different between groups. Screw-retained pressed or milled monolithic LDS ISSC, cemented directly to Ti-base abutments or LDS crowns cemented to custom ceramic abutments resist physiological chewing forces after simulated 5-year aging in the artificial mouth and presented equally high probability of survival. However, a significant decrease in load to failure was observed in LDS crowns cemented to custom ceramic abutments after fatigue. Prospective clinical trials are needed to confirm the results of this laboratory investigation.

Hybrid Implant Abutments: A Literature Review

AbstractCeramic implant abutments are becoming increasingly popular due to the growing esthetic demands of patients. Two-piece ceramic abutments have the advantages of both ceramic and titanium abutments. This study aimed to review the published articles regarding hybrid abutments and their characteristics.Published articles regarding two-piece abutments were retrieved by electronic search of PubMed, Embase, Scopus, Medline, and Google Scholar databases using certain keywords. Articles highly relevant to our topic of interest were selected and reviewed.The presence of titanium inserts in hybrid abutments can overcome the brittleness of ceramic, increase the overall fracture resistance, prevent the implant connection wear, and provide better marginal fit compared with one-piece zirconia abutments. Hybrid abutments enable the fabrication of monolithic metal-free implant restorations with optimal esthetics. Furthermore, the risk of porcelain chipping, which is a common complication of implant restorations, is eliminated due to the monolithic structure of these restorations.According to the available literature, hybrid implant abutments have shown promising results with regard to optimal esthetics in the rehabilitation of the esthetic zone. However, long-term clinical studies are required to assess the long-term durability of all-ceramic restorations supported by hybrid abutments.

The application of individualized abutment-crown integrated provisional restoration in optimizing the peri-implant soft tissue contour in the esthetic zone.

This article introduced a modified method to fabricate an individualized abutment-crown integrated provisional restoration for single-tooth implant restoration in the esthetic zone, which created a satisfactory peri-implant soft tissue architecture. Three months after the implant placement, the individualized abutment-crown integrated provisional restoration was designed and fabricated in the laboratory, by referring to the profile of natural contra-lateral tooth digitally, and seated on the implant afterwards. The peri-implant soft tissue architecture was evaluated and the Pink Esthetic Score (PES) was recorded. The provisional restoration stayed on the implant for 3 months until the individualized definitive ceramic abutment and crown were fixed on the implant. This protocol provided an alternative solution for shaping the peri-implant soft tissue morphology in the esthetic zone by using an individualized abutment-crown integrated provisional restoration and showed promising effect on the esthetics of anterior single-tooth implant restoration. The individualized abutment-crown integrated provisional restoration whose emergence profile mirroring that of the natural contra-lateral tooth, was designed with the help of computer-aided design-manufacture (CAD/CAM). It may help shaping the peri-implant soft tissue in the esthetic zone with merits of saving amount of hand labor of technicians as well as clinicians, and reducing the visits of patients.

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.

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.

Cemented vs. screw‐retained single implant all‐ceramic crowns: 5‐year results of a clinical RCT

Background: In order to overcome esthetic limitations of metal-ceramic implant reconstructions, all-ceramic crowns were introduced. Zirconia abutments demonstrated particular esthetic advantages, predominantly in cases with thin facial mucosa. Custom-made zirconia abutments can be combined with a cemented crown or, as an alternative, be directly veneered and inserted as a screw-retained reconstruction. Up to date, in clinical studies, NOe of the retention types could show a clear advantage over the other. Aim/Hypothesis: To test whether or not screw-retained all-ceramic implant-supported single crowns present similar biological and technical outcomes to cemented all-ceramic crowns after a follow-up time of 5 years. Materials and Methods: Forty-four two-piece dental implants with non-matching implant–abutment junctions were placed in single tooth gaps in the esthetic zone. Patients randomly received a screw-retained (SR) or cemented (CR) all-ceramic single reconstruction. Follow-up visits were scheduled 1–3 weeks after crown insertion, as well as at 6 months, 1, 3 and 5 years. Biological and esthetic parameters were assessed at the implant and control sites (contralateral tooth). Technical outcomes of the reconstructions were evaluated according to modified USPHS (United States Public Health Service) criteria. In addition, profilometric measurements were performed with an image analysis software. Data were statistically analyzed with Wilcoxon-Mann-Whitney, Wilcoxon and Fisher exact tests. Results: Out of 44 included subjects, 3 patients (6.8%) were not available for the 5-year follow-up (2 SR, 1 CR group). Eight reconstructions (18.1%) were lost due to technical (13.6%; 2 CR, 4 SR group; implants still present) or biological complications (4.5%; 2 CR group; implant loss). A total of 33 subjects could be reexamined. No significant differences regarding technical, radiographic and profilometric outcomes could be shown between the groups (P > 0.05). Bleeding on probing (BOP) showed significant higher mean values at implant sites for the CR group (40.0 ± 47.1%) compared to the SR group (8.3 ± 19.2%; P = 0.034). The median marginal bone level was −0.4 mm (−0.5; −0.3) in the SR group and −0.4 mm (−0.8; −0.3) in the CR group (P = 0.582). Cemented reconstructions showed a statistically significantly higher biological complication rate (36.8%, SR 0.0%; P = 0.0022), as well as a significant higher overall complication rate (68.4%, SR 22.7%, P = 0.0049) compared to screw-retained reconstructions (SR). Conclusions and Clinical Implications: At 5-years, a high rate of technical and biological complications could be observed, in particular for cemented reconstructions. This retention type was associated with a higher rate of positive inflammatory parameters (BOP), as well as with a higher incidence of peri-implant diseases. On the long run, screw-retained reconstructions appear to be the preferred type of retention when using all-ceramic reconstructions in the esthetic zone. Acknowledgements: The investigators gratefully acknowledge Prof Dr. Jürg Hüsler for analyzing the data and Gisela Müller, study monitor at the Clinic of Reconstructive Dentistry, Center for Dental Medicine, University of Zurich, for the support. Keywords: biologic complications, technical complications, ceramic abutments, cemented, screw-retained.

A Systematic Review and Meta-Analysis of the Influence of Abutment Material on Peri-implant Soft Tissue Color Measured Using Spectrophotometry.

To systematically review the current literature on the influence of abutment material (metal vs ceramic) and soft tissue thickness on peri-implant soft tissue discoloration in partially edentulous patients restored with implant-supported single crowns. An electronic MEDLINE search was performed to identify randomized controlled clinical trials (RCTs) up to and including March 2017. The search was complemented by a manual search of related bibliographies. Selection of studies was made independently by two reviewers based on the inclusion criteria. Spectrophotometric data (ΔE values) and soft tissue thickness values were extracted, and, whenever applicable, a meta-analysis using a random-effects approach was performed. The search resulted in 208 titles and 30 abstracts. Full-text analysis was performed for 13 articles, resulting in 6 included RCTs. Meta-analysis of a total of 266 abutments revealed significantly lower ΔE values for ceramic abutments when compared to the overall metal abutments (z test value = 1.99, P = .05), with a mean difference of 1.41 (95% CI 0.02, 2.80). Nonsignificant differences were found between titanium and zirconia (z test value = 1.59, P = .11). Limited information on the correlation between soft tissue thickness and ΔE values was found. Hence, it was not possible to perform a meta-analysis of this question. The color outcome of the peri-implant soft tissue might be influenced by the abutment material. Ceramic abutments appear to provide an improved color matching between peri-implant soft tissues and soft tissues around natural teeth when compared to metallic abutments. These findings support the preference for all-ceramic or "white" abutments in esthetically demanding cases.

WITHDRAWN: Interventions for replacing missing teeth: partially absent dentition.

Management of individuals presenting with partial loss of teeth is a common task for dentists. Outcomes important to the management of missing teeth in the partially absent dentition should be systematically summarized. This review recognizes both the challenges associated with such a summarization and the critical nature of the information for patients. To assess the effects of different prostheses for the treatment of partially absent dentition in terms of the following outcomes: long-term success, function, morbidity and patient satisfaction. We searched the Cochrane Oral Health Group's Trials Register (to 21 March 2011), the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2011, Issue 1), MEDLINE via OVID (1950 to March 2011) and EMBASE via OVID (1980 to March 2011). There were no restrictions regarding language or date of publication. We contacted several authors to identify non-published trials. Randomized controlled trials (RCTs) comparing different methods (including the design and materials used) of treating partial edentulism, with clinically relevant outcomes, were included in this review. Trials reporting only surrogate outcomes, such as plaque accumulation or gingival volume, were excluded from this review. Two review authors independently carried out the screening of eligible studies, assessment of dimensions of quality of trials, and data extraction. Results were expressed as mean differences for continuous data, risk ratios for dichotomous outcomes, and hazard ratios with 95% confidence intervals for time-to-event data. Twenty-one trials met the inclusion criteria for this review. Twenty-four per cent of these were assessed as being at high risk of bias and the remainder were at unclear risk of bias. The clinical heterogeneity among the included studies precluded any attempt at meta-analysis. There was insufficient evidence to determine whether one type of removable dental prosthesis (RDP) was better or worse than another. With fixed dental prostheses (FDPs), there was no evidence that high gold alloys are better or worse than other alloys, nor that gold alloys or frameworks are better or worse than titanium. There is insufficient evidence to determine whether zirconia is better or worse that other FDP materials, that ceramic abutments are better or worse than titanium, or that one cement was better or worse than another in retaining FDPs. There is insufficient evidence to determine the relative effectiveness of FDPs and RDPs in patients with shortened dental arch or to determine the relative advantages of implant supported FDPs versus tooth/implant supported FDPs. Based on trials meeting the inclusion criteria for this review, there is insufficient evidence to recommend a particular method of tooth replacement for partially edentulous patients.

A systematic review of the influence of the implant-abutment connection on the clinical outcomes of ceramic and metal implant abutments supporting fixed implant reconstructions.

The objective of this systematic review was to assess the influence of implant-abutment connection and abutment material on the outcome of implant-supported single crowns (SCs) and fixed dental prostheses (FDPs). An electronic Medline search complemented by manual searching was conducted to identify randomized controlled clinical trials, prospective and retrospective studies with a mean follow-up time of at least 3years. Patients had to have been examined clinically at the follow-up visit. Failure and complication rates were analyzed using robust Poisson regression, and comparisons were made with multivariable Poisson regression models. The search provided 1511 titles and 177 abstracts. Full-text analysis was performed for 147 articles resulting in 60 studies meeting the inclusion criteria. Meta-analysis of these studies indicated an estimated 5-year survival rate of 97.6% for SCs and 97.0% for FDPs supported by implants with internal implant-abutment connection and 95.7% for SCs and 95.8% for FDPs supported by implants with external connection. The 5-year abutment failure rate ranged from 0.7% to 2.8% for different connections with no differences between the types of connections. The total number of complications was similar between the two connections, yet, at external connections, abutment or occlusal screw loosening was more predominant. Ceramic abutments, both internally and externally connected, demonstrated a significantly higher incidence of abutment fractures compared with metal abutments. For implant-supported SCs, both metal and ceramic abutments with internal and external connections exhibited high survival rates. Moreover, implant-supported FDPs with metal abutments with internal and external connections for also showed high survival rates.

The biological complication of implant abutment materials. A systematic review and meta-analysis

Aim The goal of this review was to identify the biological complication of implant abutment materials in relation to alveolar bone around implant-supported superstructure. Methodology An electronic database search and a further manual search were directed to select RCTs, and cohort studies that give evidence about different abutment materials complication. Pocket depth, amount of rescission and crestal bone loss were attributed to alveolar bone loss. Results Fourteen clinical studies were selected from an initial search of 107 studies and the extraction of the analysis data were tabled according to complication output. Pocket probing depth were documented in eight studies, PPD around Zirconium implant abutments was 3.2 mm versus 3.4 mm for Titanium abutments. Five studies examined the recession index for Zirconium and Titanium implant abutments. The RI ranged from 0 to 0.4 at Titanium implant abutments and 0 to 0.3 at Zirconium implant abutments. Alveolar bone loss around Zirconia abutments was reported to differ from 0.2-1.48 mm and 0.3-1.43mm at Titanium abutments. Conclusion The data reported in this systematic review did not give an evidence for the complication regarding all ceramic versus metallic implant abutment. However, it can be concluded that the assessment of the randomized clinical trials did not provide an absolute decision for the choice of ceramic or metallic as implant abutment material in relation to alveolar bone response. The meta-analysis presented a statistically significant difference between abutment material with superiority for the all ceramic abutments over metallic abutment providing a favorable response of Marginal Bone Loss, but non-statistically significant regarding Pocket Probing Depth and Recession Index of soft tissue.

Pilares cerâmicos na implantodontia: revisão de literatura

Resumo Os pilares protéticos, usados como intermediários entre a prótese e o implante, são feitos de titânio e outros metais, que possuem estrutura confiável. A cor acinzentada desses metais, acrescidos a recessão gengival e a camadas finas de tecidos adjacentes, acaba exposta, o que compromete a estética. Com isso, foram introduzidos os pilares cerâmicos (zircônia, alumina ou zircônia/alumina) que fornecem boas propriedades ópticas, assim como biocompatibilidade e estética duradoura. O objetivo desse estudo foi avaliar, através de uma revisão sistemática da literatura, as taxas de sobrevivência dos pilares metálicos e cerâmicos, bem como seus principais tipos de falha. Foi realizada uma pesquisa nas bases de dados Pubmed de 1999 a 2015 utilizando as palavras-chave: cerâmicas (ceramics), pilar (abutment), implantes dentários (dental implants) e prótese parcial fixa (partial fixed denture). Foram selecionados 16 artigos de pesquisa clínica e estudos de coorte. Segundo os estudos, não houve diferença significativa nos índices biológicos e radiográficos entre os pilares cerâmicos e metálicos, quando comparados uns com os outros e com os dentes naturais, em estudos de até 11 anos. Também não foi observada perda significativa de osso marginal entre a avaliação inicial e a última avaliação para ambos tipos de pilares (titânio e cerâmicos). Pilares de alumina têm taxa de sobrevivência de 94,7% a 100% em estudo de acompanhamento clínico de até 7 anos. Pilares de zircônia têm taxa de sobrevivência semelhante aos pilares de titânio (100%) em estudos de acompanhamento clínico de até 11 anos. Apenas em um estudo de 7 anos, a taxa de sobrevivência caiu para 97,6%, para os pilares de zircônia. Os modos de falha encontrados para os pilares foram fratura e afrouxamento do parafuso. A semelhança no comportamento mecânico e biológico entre os materiais torna os pilares cerâmicos uma boa alternativa na Implantodontia.

Influence of Metal and Ceramic Abutments on the Stress Distribution Around Narrow Implants: A Photoelastic Stress Analysis.

This study aimed to compare, through photoelastic analysis, the distribution of stresses around narrow implants with external hexagon (EH) and Morse taper (MT) connections, when single crowns made with metal and ceramic abutments were used. Six photoelastic models were prepared, simulating the use of narrow EH and MT implants replacing a lateral incisor. These 2 groups received 3 different abutments: prefabricated metal abutments, customized metal abutments, and customized zirconia abutments. All crowns were identical and made with a leucite reinforced glass-ceramic. Vertical loads of 0 to 100 N were applied on the palatal surface of the crowns, and the photoelastic stress fringes developed in each model were captured in a high-definition video, and digital photographs were taken at 100 N. The abutment type and material influenced the stress distribution patterns around narrow implants with EH and MT connections. Stresses were generated mainly around the apical and lingual regions of the implants. For both connections, the prefabricated metal abutments presented better stress distribution around the implants when compared to customized metal and zirconia abutments because low stress levels were developed in smaller areas around the implants.

Fatigue Behavior of Computer-Aided Design/Computer-Assisted Manufacture Ceramic Abutments as a Function of Design and Ceramics Processing.

Zirconia is being widely used, at times apparently by simply copying a metal design into ceramic. Structurally, ceramics are sensitive to both design and processing (fabrication) details. The aim of this work was to examine four computer-aided design/computer-assisted manufacture (CAD/CAM) abutments using a modified International Standards Organization (ISO) implant fatigue protocol to determine performance as a function of design and processing. Two full zirconia and two hybrid (Ti-based) abutments (n = 12 each) were tested wet at 15 Hz at a variety of loads to failure. Failure probability distributions were examined at each load, and when found to be the same, data from all loads were combined for lifetime analysis from accelerated to clinical conditions. Two distinctly different failure modes were found for both full zirconia and Ti-based abutments. One of these for zirconia has been reported clinically in the literature, and one for the Ti-based abutments has been reported anecdotally. The ISO protocol modification in this study forced failures in the abutments; no implant bodies failed. Extrapolated cycles for 10% failure at 70 N were: full zirconia, Atlantis 2 × 10(7) and Straumann 3 × 10(7); and Ti-based, Glidewell 1 × 10(6) and Nobel 1 × 10(21). Under accelerated conditions (200 N), performance differed significantly: Straumann clearly outperformed Astra (t test, P = .013), and the Glidewell Ti-base abutment also outperformed Atlantis zirconia at 200 N (Nobel ran-out; t test, P = .035). The modified ISO protocol in this study produced failures that were seen clinically. The manufacture matters; differences in design and fabrication that influence performance cannot be discerned clinically.