Fracture strength of zirconia implant abutments on narrow diameter implants with internal and external implant abutment connections: A study on the titanium resin base concept

BACKGROUND There is limited knowledge regarding the strength of zirconia abutments with internal and external implant abutment connections and zirconia abutments supported by a titanium resin base (Variobase, Straumann) for narrow diameter implants. OBJECTIVES To compare the fracture strength of narrow diameter abutments with different types of implant abutment connections after chewing simulation. MATERIAL AND METHODS Hundred and twenty identical customized abutments with different materials and implant abutment connections were fabricated for five groups: 1-piece zirconia abutment with internal connection (T1, Cares-abutment-Straumann BL-NC implant, Straumann Switzerland), 1-piece zirconia abutment with external hex connection (T2, Procera abutment-Branemark NP implant, Nobel Biocare, Sweden), 2-piece zirconia abutments with metallic insert for internal connection (T3, Procera abutment-Replace NP implant, Nobel Biocare), 2-piece zirconia abutment on titanium resin base (T4, LavaPlus abutment-VarioBase-Straumann BL-NC implant, 3M ESPE, Germany) and 1-piece titanium abutment with internal connection (C, Cares-abutment-Straumann BL-NC implant, Straumann, Switzerland). All implants had a narrow diameter ranging from 3.3 to 3.5 mm. Sixty un-restored abutments and 60 abutments restored with glass-ceramic crowns were tested. Mean bending moments were compared using ANOVA with p-values adjusted for multiple comparisons using Tukey's procedure. RESULTS The mean bending moments were 521 ± 33 Ncm (T4), 404 ± 36 Ncm (C), 311 ± 106 Ncm (T1) 265 ± 22 Ncm (T3) and 225 ± 29 (T2) for un-restored abutments and 278 ± 84 Ncm (T4), 302 ± 170 Ncm (C), 190 ± 55 Ncm (T1) 80 ± 102 Ncm (T3) and 125 ± 57 (T2) for restored abutments. For un-restored abutments, C and T4 had similar mean bending moments, significantly higher than those of the three other groups (p < .05). Titanium abutments (C) had significantly higher bending moments than identical zirconia abutments (T1) (p < .05). Zirconia abutments (T1) with internal connection had higher bending moments than zirconia abutments with external connection (T2) (p < .05). For all test groups, the bending moments were significantly reduced when restored with all-ceramic crowns. CONCLUSIONS For narrow diameter abutments, the fracture strength of 2-piece internal connected zirconia abutments fixed on titanium resin bases was similar to those obtained for 1-piece titanium abutments. Narrow diameter zirconia abutments with internal connection exhibited higher fracture strength than zirconia abutments with an external connection. Titanium abutments with an internal connection were significantly stronger than identical zirconia abutments

Improvements in Implant Dentistry over the Last Decade: Comparison of Survival and Complication Rates in Older and Newer Publications

Purpose: The objective of this systematic review was to assess and compare the survival and complication rates of implant-supported prostheses reported in studies published in the year 2000 and before, to those reported in studies published after the year 2000. Materials and Methods: Three electronic searches complemented by manual searching were conducted to identify 139 prospective and retrospective studies on implant-supported prostheses. The included studies were divided in two groups: a group of 31 older studies published in the year 2000 or before, and a group of 108 newer studies published after the year 2000. Survival and complication rates were calculated using Poisson regression models, and multivariable robust Poisson regression was used to formally compare the outcomes of older and newer studies. Results: The 5-year survival rate of implant-supported prostheses was significantly increased in newer studies compared with older studies. The overall survival rate increased from 93.5% to 97.1%. The survival rate for cemented prostheses increased from 95.2% to 97.9%; for screw-retained reconstruction, from 77.6% to 96.8%; for implant-supported single crowns, from 92.6% to 97.2%; and for implant-supported fixed dental prostheses (FDPs), from 93.5% to 96.4%. The incidence of esthetic complications decreased in more recent studies compared with older ones, but the incidence of biologic complications was similar. The results for technical complications were inconsistent. There was a significant reduction in abutment or screw loosening by implant-supported FDPs. On the other hand, the total number of technical complications and the incidence of fracture of the veneering material was significantly increased in the newer studies. To explain the increased rate of complications, minor complications are probably reported in more detail in the newer publications. Conclusions: The results of the present systematic review demonstrated a positive learning curve in implant dentistry, represented in higher survival rates and lower complication rates reported in more recent clinical studies. The incidence of esthetic, biologic, and technical complications, however, is still high. Hence, it is important to identify these complications and their etiology to make implant treatment even more predictable in the future

Fracture strength of zirconia implant abutments on narrow diameter implants with internal and external implant abutment connections: a study on the titanium resin base concept

There is limited knowledge regarding the strength of zirconia abutments with internal and external implant abutment connections and zirconia abutments supported by a titanium resin base (Variobase, Straumann) for narrow diameter implants

Zirconia reconstructions cemented on non-original titanium bases may result in increased bleeding on probing, probing depth values and varying mean marginal bone levels

PURPOSE To assess the clinical, technical, and esthetic outcomes of directly veneered zirconia abutments cemented onto non-original titanium bases over 3 years. MATERIALS AND METHODS A total of 24 healthy patients with a single missing tooth in the maxilla or mandible (incisors, canines, or premolars) received a two-piece implant with a screw-retained veneered zirconia restoration extraorally cemented on a titanium base abutment. Baseline measurements and follow-up examinations were performed at 6 months, 1 year, and 3 years following loading. Radiographic, clinical, technical, and esthetic parameters were assessed. Wilcoxon signed rank test was used to analyze the data. RESULTS Mean marginal bone levels measured 0.54 ± 0.39 mm (median: 0.47 mm, range: 0.07 mm to 1.75 mm) at baseline and 0.52 ± 0.39 mm (median: 0.39 mm, range: 0.06 mm to 1.33 mm) at 3 years. Mean probing depth around the implants increased from 3.0 ± 0.6 mm at baseline to 3.8 ± 0.8 mm at 3 years (P = .001). Bleeding on probing changed from 27.1% ± 20.7% (baseline) to 51.5% ± 26.1% (3 years) (P = .001). The mean plaque control record amounted to 11.1% ± 21.2% (baseline) and 14.4% ± 13.89% (3 years) (P = .261). Two implants were lost at 3.5 and 30 months postloading due to peri-implantitis, resulting in a 91.7% implant survival rate. Patient satisfaction was high at 3 years. CONCLUSION Zirconia restorations cemented onto the tested non-original titanium bases should not be recommended for daily clinical use, as they were associated with significant increases in BOP and PD values and varying marginal bone levels 3 years after placement

Veneered zirconia abutments cemented on non-original titanium bases: 1-year results of a prospective case series

To assess clinical, technical, and esthetic outcomes of veneered zirconia reconstructions cemented on non-original titanium bases over 1 year

Veneered zirconia abutments cemented on non‐original titanium bases: 1‐year results of a prospective case series

Objectives To assess clinical, technical, and esthetic outcomes of veneered zirconia reconstructions cemented on non‐original titanium bases over 1 year. Materials and methods Twenty‐four healthy patients presented with one missing tooth in the anterior maxilla or mandible and received a two‐piece dental implant. The implants were restored with a screw‐retained crown using a directly veneered zirconia reconstruction, which was extraorally cemented on a titanium base. After crown insertion, patients were scheduled for a baseline examination and re‐examined at 6 months and at 1 year of loading. Measurements included biological, technical, and esthetic parameters. Data were analyzed with nonparametric tests. Results Mean marginal bone levels measured 0.54 ± 0.39 mm (median: 0.47, range: 0.07–1.75 mm) at baseline and 0.54 ± 0.45 mm (median: 0.44, range: 0.06–1.52 mm) at 1 year. Mean probing depth (PD) (3.0 ± 0.6 mm at baseline to 3.5 ± 0.7 mm at 1 year [p = 0.002]), bleeding on probing (BOP) (27.1% ± 20.7% at baseline to 43.9% ± 28.0% at 1 year [p = 0.041]), plaque index (PI) (11.1% ± 21.2% at baseline to 18.2% ± 21.8% at 1 year [p = 0.381]) increased, whereas the width of the keratinized mucosa decreased from baseline to 1 year (3.1 ± 1.3 mm at baseline to 3.0 ± 1.2 mm at 1 year [p = 0.398]). Four implants (16.7%) were diagnosed with peri‐implantitis (BOP positive, bone loss >1 mm) during the 1‐year observation period. One implant was lost at 3 ½ months, resulting in a 95.8% survival rate. Four technical complications occurred and led to 83.3% complication‐free reconstructions. Conclusion A significant increase in PD and BOP values was observed using directly veneered zirconia reconstructions cemented on non‐original titanium base

Tairona culture artefacts, Museo del Oro, Bogota, Colombia, 1977, [14] [picture] /

Condition: Good.; Title devised by cataloguer based on inscription on reverse.; Part of Wolfgang Sievers photographic archive.; Sievers number: EK-4560-add88 (devised number).; Inscriptions: "Tairona-20289".; Also available in an electronic version via the Internet at: http://nla.gov.au/nla.pic-vn4195875

Randomized controlled clinical trial comparing one-piece and two-piece dental implants supporting fixed and removable dental prostheses: 4- to 6-year observations

OBJECTIVES To test whether or not a one- (S1) and a two-piece (S2) dental implant systems render the same biological, technical, and esthetic outcomes regarding implants and implant-supported reconstructions over an observation period of 4 to 6 years. MATERIALS AND METHODS Sixty patients were randomly assigned to receive S1 or S2 implants. The implants were restored with either fixed or removable prostheses. The insertion of the final reconstruction was chosen as baseline. One-year and 4- to 6-year (FU-5) measurements included biological (e.g. marginal bone level, probing pocket depth, peri-implant mucositis, and peri-implantitis), technical (e.g. fracture or loosening of prosthetic screws, fracture or loosening of abutments, fracture of framework, and/or veneering ceramic (minor, major), loss of retention for cemented restorations), and esthetic parameters (visibility of the crown margin, shimmering of the implant through the mucosa, the level of the facial margo mucosae compared to the contralateral tooth or implant site and the modified papilla index) for implants and reconstructions. Survival and success rates of implants and reconstructions were calculated. Because of the asymmetric data distributions, nonparametric statistical methods were applied. RESULTS The implant-based analysis revealed a cumulative implant survival rate of 97.9% (S1: 96.6%; S2: 98.9%) at FU-5. The median marginal bone level for group S1 changed from 0.51 mm at baseline to 0.49 mm at FU-5 and for group S2 from 1.02 mm to 1.35 mm (P 0.05). CONCLUSIONS Both implant systems reveal high survival rates on the implant and prosthetic level. Apart from marginal bone-level changes, biological and technical outcomes did not reveal significant differences between the two implant systems