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

OBJECTIVES 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). METHODS 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 3 years. 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. RESULTS 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. CONCLUSION 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

A multicenter randomized controlled clinical pilot study of buccally micro‐veneered lithium‐disilicate and zirconia crowns supported by titanium base abutments: 1‐year outcomes

Objectives: To investigate survival rates, technical and biologic outcomes of buccally micro-veneered all-ceramic single implant crowns. Material and methods: Sixty subjects randomly received immediately or early placed implants. Crowns out of lithium-disilicate (n = 30) and zirconia-ceramic (n = 30) were bonded to titanium-base-abutments. Restorations were inspected at baseline (BL) and during follow-up visits (6, 12 months). Technical and biologic parameters were recorded. Data were analysed descriptively. Differences between groups were tested with Student's t-test. Paired T-test was used when comparing data from the same implant or tooth over time. Linear model repeated measures were used to test differences between materials over time. Differences in counts were evaluated using Pearson Chi-square test. The level of significance was at p < .05. Results: After a mean observation time of 13.2 ± 2.4 months, 54 restorations were re-examined. The implant survival rate was 98.3%, and the restoration survival rate was 100%. One early implant failure occurred. Two minor chippings occurred in lithium-disilicate restorations. No chippings or fractures occurred in any zirconia restorations at 1 year (0%). The technical complication rate was 3.7%, with 7.7% complications among the lithium-disilicate restorations and no differences between the two materials (p = .558). At 1-year follow-up, mean Bleeding on Probing (BOP) was higher at implants (0.27 ± 0.3) than adjacent teeth (0.17 ± 0.18) (p = .046) with no differences between materials (p = .36). Differences in pocket probing depth (PPD) between implants and adjacent teeth were significant (p < .01). Jemt Index improved significantly from BL to 1-y-follow-up (p < .001). Conclusions: Preliminary results were good, suggesting that the ceramic type does not impact technical and biologic parameters. Keywords: all-ceramic single crowns; chipping; clinical trials; implant-borne reconstructions; technical outcome

Cemented vs screw-retained zirconia-based single implant reconstructions: A 3-year prospective randomized controlled clinical trial

OBJECTIVES The objective of the present randomized clinical trial was to test whether or not the use of screw-retained all ceramic implant-borne reconstructions results in clinical, technical, and biologic outcomes similar to those obtained with cemented all ceramic reconstructions. The hypothesis was that there is no difference in clinical, technical, and biological parameters between the two types of retention. MATERIALS AND METHODS Forty-four patients randomly received 20 cemented reconstruction (CR) and 24 screw-retained (SR) all ceramic single crowns on two-piece dental implants with nonmatching implant-abutment junctions. All patients were recalled after crown insertion, at 6 months, 1 year, as well as at 3 years. At these visits, biological and radiographic evaluations were performed. Technical outcomes were assessed using modified USPHS (United States Public Health Service) criteria. Data were statistically analyzed with Wilcoxon-Mann-Whitney, Wilcoxon and Fisher exact tests. RESULTS During 3 years of follow-up, eight patients (18.2%) lost the reconstruction due to technical (6 patients, 13.6%, 2 CR and 4 SR group) or biological complications (2 patients, 4.5%, only CR group). Thirty-two subjects with 18 SR and 14 CR reconstructions attended the FU-3Y, whereas four patients (9.1%, 2 SR, 2 CR) were not available (drop-outs). Biological, technical, and radiographic outcomes did not differ significantly between the groups (P > 0.05). One implant (2.3%) was lost in the CR group. One more cemented crown (2.3%) had to be removed because of peri-implant disease. Six patients (13.6%) lost the reconstructions due to a fracture of the zirconia abutment (4 SR, 2 CR). The mean marginal bone level at 3 years was -0.4 mm (-0.5; -0.3) in group SR and - 0.4 mm (-0.6; -0.3) group CR (P = 0.864). CONCLUSIONS At 3 years, CR and SR exhibited similar survival technical, biological and radiographic outcomes. The rate of technical complications was high in both groups

Effect of splinting scan bodies on the trueness of complete-arch digital implant scans with 5 different intraoral scanners

Statement of problem: The absence of fixed reference points can affect the trueness of complete-arch intraoral digital implant scans. The effect of splinting intraoral scan bodies (ISBs) or the inclusion of artificial landmarks (AL) on the trueness of complete-arch digital implant scans is still unclear. Purpose: The purpose of this study was to analyze the effect of splinting ISBs or the inclusion of AL on the trueness of complete-arch digital implant scans with 5 intraoral scanners (IOSs). Material and methods: Six tissue-level dental implants (Straumann Tissue Level) were placed in an edentulous patient, and the correspondent definitive cast was digitized with a desktop scanner (IScan4D LS3i) to obtain the reference digital cast. Digital scans (n=10) were performed with 5 IOSs: TRIOS 4, Virtuo Vivo, Medit i700, iTero Element 5D, and Cerec Primescan. Three different scanning techniques were evaluated: conventional (cIOSs), splinted (sIOSs), and AL (AL-IOSs). The scan data obtained were imported into a metrology software program and superimposed to the reference digital cast by using a best-fit algorithm. The overall deviations of the positions of the ISBs were evaluated by using the root-mean-square (RMS) error (α=.05). Results: The mean ±standard deviation trueness values for the cIOSs, sIOSs, and AL-IOSs groups were 48 ±8 µm, 53 ±7 µm, and 49 ±11 µm, respectively, with no statistically significant differences (P=.06). Significant differences were found for the IOSs used with each technique (P<.001). Primescan (27 ±4 µm cIOSs; 28 ±3 µm sIOSs; 31 ±3 µm AL-IOSs) showed significantly higher trueness than iTero 5D (47 ±5 µm cIOSs; 47 ±4 µm sIOSs; 50 ±6 µm AL-IOSs) (P=.002) and TRIOS 4 (93 ±18 µm cIOSs; 76 ±18 µm sIOSs; 107 ±13 µm AL-IOSs) (P=.001) for all techniques. In addition, no significant differences were found between the techniques by using iTero 5D or Primescan (P=.348 and P=.059, respectively). Conclusions: The cIOSs, sIOSs, and AL-IOSs techniques showed similar trueness. The IOS used influenced the trueness of complete-arch digital implant scans.info:eu-repo/semantics/acceptedVersio

Impact of Gluma Desensitizer on the tensile strength of zirconia crowns bonded to dentin: an in vitro study

This study tested the impact of Gluma Desensitizer on the tensile strength of zirconia crowns bonded to dentin. Human teeth were prepared and randomly divided into six groups (N = 144, n = 24 per group). For each tooth, a zirconia crown was manufactured. The zirconia crowns were cemented with: (1) Panavia21 (PAN), (2) Panavia21 combined with Gluma Desensitizer (PAN-G), (3) RelyX Unicem (RXU), (4) RelyX Unicem combined with Gluma Desensitizer (RXU-G), (5) G-Cem (GCM) and (6) G-Cem combined with Gluma Desensitizer (GCM-G). The initial tensile strength was measured in half (n = 12) of each group and the other half (n = 12) subjected to a chewing machine (1.2 Mio, 49N, 5°C/50°C). The cemented crowns were pulled in a Universal Testing Machine (1mm/min, Zwick Z010) until failure occurred and tensile strength was calculated. Data were analyzed with one-way and two-way ANOVA followed by a post hoc Scheffé test, t test and Kaplan-Meier analysis with a Breslow-Gehan analysis test (α = 0.05). After the chewing simulation, the self-adhesive resin cements combined with Gluma Desensitizer showed significantly higher tensile strength (RXU-G, 12.8 ± 4.3MPa; GCM-G, 13.4 ± 6.2MPa) than PAN (7.3 ± 1.7MPa) and PAN-G (0.9 ± 0.6). Within the groups, PAN, PAN-G and RXU resulted in significantly lower values when compared to the initial tensile strength; the values of all other test groups were stable. In this study, self-adhesive resin cements combined with Gluma Desensitizer reached better long-term stability compared to PAN and PAN-G after chewing simulatio

Three-Dimensional Peri-Implant Tissue Changes in Immediately vs. Early Placed Tapered Implants Restored with Two Different Ceramic Materials—1 Year Results

Background: A prospective multi-center randomized controlled clinical trial was performed to digitally analyze tissue volume changes in immediately and early placed implants with simultaneous bone augmentation restored with two different all-ceramic materials. Methods: A total of 60 patients received 60 bone-level tapered implants (BLT, Straumann AG) immediately (n = 30) or early placed, 8–10 weeks after tooth extraction, (n = 30). Implants were restored with all-ceramic single crowns fabricated out of zirconia (Lava Plus, 3M), or lithium disilicate (E.max CAD, Ivoclar Vivadent AG) bonded to titanium base abutments (Variobase for Cerec, Straumann AG). Impressions were taken at baseline (BL), 6 and 12 months, and STL data were used to define an area of interest (AOI) to analyze peri-implant volume changes and midfacial recessions. Results: For immediate placement, a mean volume loss of −5.56 mm3 (±5.83 mm3) was found at 6 months, and of −6.62 mm3 (±6.56 mm3) at 12 months. For early placement, a mean volume loss of −1.99 mm3 (±5.82 mm3) at 6 months, and of −3.7 mm3 (±5.62 mm3) at 12 months was found. The differences in volume loss at 12 months between the two implant placement protocols were significant (p = 0.005). In both groups, mean midfacial recessions of 0.48 mm (±0.52) occurred. Conclusions: A more pronounced peri-implant volume loss can be expected 12 months after immediate implant placement compared with early placement

Restorative angle of zirconia restorations cemented on non-original titanium bases influences the initial marginal bone loss: 5-year results of a prospective cohort study

AIM: To assess radiographic, restorative, clinical and technical outcomes as well as patient satisfaction of directly veneered zirconia restorations cemented on non-original titanium bases over 5 years. MATERIAL AND METHODS: Twenty-four patients with a single missing tooth in the aesthetic zone were recruited. All patients received a two-piece implant with a screw-retained veneered zirconia restoration cemented extraorally on a titanium base abutment. Marginal bone levels (MBL), marginal bone changes, technical complications, patient satisfaction and clinical parameters including probing depth, bleeding on probing and plaque index were assessed at crown delivery (baseline), at 1 year (FU-1) and 5 years (FU-5) of follow-up. To investigate the relationship between restorative angle and MBL as well as marginal bone changes (bone loss/bone gain), correlation tests and linear regression models were carried out. RESULTS: Twenty-two patients were available for re-examination at 5 years. The mean MBL amounted to 0.54 ± 0.39 mm at baseline, and to 0.24 ± 0.35 at FU-5 (=bone gain) (p  .05). At distal sites, no correlations or associations between the restorative angle and MBL or marginal bone changes were found regardless of the time point. During the 5-year follow-up, 5 technical complications occurred, mainly within the first year and mostly chippings. All patients were entirely satisfied with their implant-supported restoration at 5 years. CONCLUSION: Within the limitations of the present study, the restorative angle of implant-supported crowns on non-original titanium bases might influence the initial marginal bone loss but without affecting their favourable long-term clinical performance. A restorative angle of <40° may limit the initial marginal bone loss at implant-supported crowns with titanium bases

13-year follow-up of a randomized controlled study on zirconia and titanium abutments

OBJECTIVES: To assess survival rates and compare technical, biological, and esthetic outcomes of customized zirconia and titanium abutments at 13 years post loading. MATERIALS AND METHODS: Initially, 22 patients with 40 implants in posterior regions were included. The sites were randomly assigned to 20 customized zirconia abutments with cemented all ceramic crowns (ACC) and 20 customized titanium abutments with cemented metal ceramic crowns (MCC). At a mean follow-up of 13.4 years, patients were examined and implants/restorations assessed for survival and technical complications, as well as biological and esthetic outcomes (pocket probing depth [PPD], bleeding on probing [BOP], plaque control record [PCR], bone level [BL], papilla index [PAP], mucosal thickness, and recession (distance of the margo mucosae [MM]/margo gingivae MG)). Descriptive analyses were performed for all outcome measures. RESULTS: Fifteen patients with 21 abutments (13 zirconia, 8 titanium) were examined at 13 years. The drop-out rate was 25% (patient level). The technical survival rate of the abutments was 100%. The survival rate on the restorative level (crowns) was 100%. The assessed biological outcomes (PPD, PCR, BOP, BL) and esthetic outcomes (MG, PAP) were similar. CONCLUSIONS: Zirconia and titanium abutments supporting single implant-borne restorations rendered a high survival rate and minimal differences in terms of technical, biological, and esthetic outcomes at 13 years of follow-up

Five-year randomized controlled clinical study comparing cemented and screw-retained zirconia-based implant-supported single crowns

OBJECTIVES To compare screw-retained and cemented all-ceramic implant-supported single crowns regarding biological and technical outcomes over a 5-year observation period. MATERIALS AND METHODS In 44 patients, 44 two-piece dental implants were placed in single-tooth gaps in the esthetic zone. Patients randomly received a screw-retained (SR) or cemented (CR) all-ceramic single crown and were then re-examined annually up to 5 years. Outcome measures included: clinical, biological, technical, and radiographic parameters. Data were statistically analyzed with Wilcoxon-Mann-Whitney, Wilcoxon, and Fisher's exact tests. RESULTS During the observation period, three patients (6.8%) were loss to follow-up. Eight restorations (18.2%, CI (8.2%, 32.7%)) were lost due to technical (6 patients, 13.6% (CI (5.2%, 27.4%)), 2 CR and 4 SR group, intergroup p = .673; implants still present) or biological complications (2 patients, 4.5% (CI (0.6%, 16.5%)), only CR group, intergroup p = .201, both implants lost). This resulted in a survival rate of 81.2% (CI (65.9%, 90.1%)) on the restorative level (18 SR; 15 CR, 3 lost to follow-up). At the 5-year follow-up, the median marginal bone levels were located slightly apical relative to the implant shoulder with 0.4 mm (0.5; 0.3) (SR) and 0.4 mm (0.8; 0.3) (CR) (intergroup p = .582). Cemented restorations demonstrated a significantly higher biological complication rate (36.8%, SR: 0.0%; intergroup p = .0022), as well as a significantly higher overall complication rate (68.4%, SR: 22.7%, intergroup p = .0049). All other outcomes did not differ significantly between the two groups (p > .05). CONCLUSIONS All-ceramic single-tooth restorations on two-piece dental implants resulted in a relatively low survival rate. Cemented restorations were associated with a higher biological and overall complication rate than screw-retained restorations

Učinak bojenja i starenja na parametar translucencije CAD/CAM materijala

Objectives: To evaluate different intervals of exposure to staining solutions and artificial aging on translucency parameter (TP 00) of CAD-CAM materials. Material and Methods: One millimeter thick square-shaped specimens (N = 288) were cut from Cerasmart (CS), IPS e.max (IE), Lava Ultimate (LU), Shofu HC (SH), Vita Enamic (VE), and Vita Suprinity (VS) and were divided into laboratory and chairside polishing. Reflection wavelength spectra, CIE D65 standard illuminant, 2 ° standard observer, SCI, UV included, SAV aperture, 6 mm diameter, were recorded at 10 nm sensitivity against white and black calibration tiles using a benchtop spectrophotometer. Subsequently, they were converted into CIEDE 2000 TP 00. After baseline measurements (T0), the specimens were divided as follows (n = 8): staining in coffee (C) and wine (W), for 60 (T1) and 120 hours (T2), and accelerated artificial aging (A). Artificial aging (ISO 4892-2 standard) was performed in two cycles of 150 KJ/m 2, for T1 and T2, respectively. TP measurements were repeated at T1 and T2. Data of TP 00 retention were submitted to analysis of variance and Fisher’s PLSD multiple comparison test (α=0.05). Results: Fisher’s PLSD critical differences among materials, time intervals and staining/aging were 0.16, 0.11 and 0.11, respectively. SH showed the highest TP 00 followed by LU > CS > IE = VS > VE. For all time intervals, the lowest TP 00 retention was observed with C. W, and A presented similar values. Conclusions: Translucency Parameter was material, time and staining/aging-dependent material. In majority of cases, it decreased upon staining/aging.Svrha rada: Procijeniti utjecaj različitih intervala izloženosti otopinama za bojenje i umjetnom starenju na parameter translucencije (TP 00) CAD/CAM materijala.Materijal i metode: Uzorci kvadratnog oblika debljine 1 mm (N = 288) izrezani su iz blokova Cerasmart (CS), IPS e.max (IE), Lava Ultimate (LU), Shofu HC (SH), Vita Enamic (VE) i Vita Suprinity ( VS) te su razvrstani u skupine u kojima je provedeno poliranje ili u laboratoriju ili u ordinaciji. Mjereni su referentnim spektrofotometrom spektri valne duljine refleksije (standardno osvjetljenje CIE D65, standardni promatrač od 2°, SCI, uključen UV, otvor SAV, promjer 6 mm) pri osjetljivosti od 10 nm na bijelim i crnim kalibracijskim pločicama i pretvoreni u CIEDE 2000 TP 00 . Nakon početnih mjerenja (T0) uzorci su podijeljeni na sljedeći način (n = 8): bojenje u kavi (C) i vinu (W) 60 (T1) i 120 sati (T2) te ubrzano umjetno starenje (A) . Umjetno starenje (ISO 4892-2 standard) obavljeno je u dvama ciklusima od 150 KJ/m2, za T1, odnosno T2. Mjerenja TP-a ponovljena su nakon T1 i T2. Podatci o TP 00 podvrgnuti su analizi varijance Fisherovim PLSD- testom višestruke usporedbe (α = 0,05).Rezultati: Kritične razlike Fisherova PLSD-testa između materijala, vremenskih intervala i bojenja/starenja bile su 0,16, 0,11, odnosno 0,11. SH je imao najviši TP 00 , a zatim slijede LU > CS > IE = VS > VE. Za sve intervale zabilježeno je najmanje zadržavanje TP 00 kod C-a. Slične vrijednosti imali su W i A. Zaključci: Parametar translucencije ovisio je o materijalu, vremenu i bojenju/starenju. U većini slučajeva smanjio se nakon bojenja/starenja