Anterior implant restorations with a convex emergence profile increase the frequency of recession: 12-month results of a randomized controlled clinical trial.

AIM: To test whether the emergence profile (CONVEX or CONCAVE) of implant-supported crowns influences the mucosal margin stability up to 12 months after insertion of the final restoration. MATERIALS AND METHODS: Forty-seven patients with a single implant in the anterior region were randomly allocated to one of three groups: (1) CONVEX (n = 15), implant provisional and an implant-supported crown both with a convex profile; (2) CONCAVE (n = 16), implant provisional and an implant-supported crown both with a concave profile; (3) CONTROL (n = 16), no provisional (healing abutment only) and an implant-supported crown. All patients were recalled at baseline, 6, and 12 months. The stability of mucosal margin along with clinical, aesthetic, and profilometric outcomes as well as time and costs were evaluated. To predict the presence of recession, multivariable logistic regressions were performed and linear models using generalized estimation equations were conducted for the different outcomes. RESULTS: Forty-four patients were available at 12 months post-loading. The frequency of mucosal recession amounted to 64.3% in group CONVEX, 14.3% in group CONCAVE, and 31.4% in group CONTROL. Regression models revealed that a CONVEX profile was significantly associated with the presence of recessions (odds ratio: 12.6, 95% confidence interval: 1.82-88.48, p = .01) compared with the CONCAVE profile. Pink aesthetic scores amounted to 5.9 in group CONVEX, 6.2 in group CONCAVE, and 5.4 in group CONTROL, with no significant differences between the groups (p = .735). Groups CONVEX and CONCAVE increased the appointments and costs compared with the CONTROL group. CONCLUSIONS: The use of implant-supported provisionals with a CONCAVE emergence profile results in a greater stability of the mucosal margin compared with a CONVEX profile up to 12 months of loading. This is accompanied, however, by increased time and costs compared with the absence of a provisional and may not necessarily enhance the aesthetic outcomes. TRIAL REGISTRATION: German Clinical Trials Register; DRKS00009420.

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 bases.

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 < 0.001). Patient-level analyses demonstrated a frequency of peri-implant mucositis of 7.7% (S1) and 10.0% (S2) and for peri-implantitis of 7.7% (S1) and 13.3% (S2) at FU-5. The patient-based cumulative implant survival rate was 94.6% (S1: 92.3%; S2: 96.7%). The overall patient-based biological complication rate amounted to 15.4% (S1) and to 23.3% (S2) (P = 0.517), whereas the overall technical complication rates were 30.8% (S1) and 13.3% (S2) (P = 0.349). The prosthetic survival rates were 93.1% for S1 and 100% for S2 (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.

Digital technologies to support planning, treatment, and fabrication processes and outcome assessments in implant dentistry. Summary and consensus statements. The 4th EAO consensus conference 2015.

OBJECTIVE: The task of this working group was to assess the existing knowledge in computer-assisted implant planning and placement, fabrication of reconstructions applying computers compared to traditional fabrication, and assessments of treatment outcomes using novel imaging techniques. MATERIAL AND METHODS: Three reviews were available for assessing the current literature and provided the basis for the discussions and the consensus report. One review dealt with the use of computers to plan implant therapy and to place implants in partially and fully edentulous patients. A second one focused on novel techniques and methods to assess treatment outcomes and the third compared CAD/CAM-fabricated reconstructions to conventionally fabricated ones. RESULTS: The consensus statements, the clinical recommendations, and the implications for research, all of them after approval by the plenum of the consensus conference, are described in this article. The three articles by Vercruyssen et al., Patzelt & Kohal, and Benic et al. are presented separately as part of the supplement of this consensus conference.

Spectrophotometric analysis of fluorescent zirconia abutments compared to "conventional" zirconia abutments: A within subject controlled clinical trial.

BACKGROUND: Zirconia abutments are frequently used for implant-supported single crowns. Even though demonstrating esthetic benefits compared to metal abutments, zirconia abutments lead to an increased brightness of the peri-implant mucosa compared to natural teeth and are not ideal from an esthetic point of view. PURPOSE: To test whether or not a fluorescent hybrid zirconia abutment offers superior esthetics compared to a non-fluorescent one-piece zirconia abutment based on spectrophotometric analysis. MATERIALS AND METHODS: In 24 patients with 24 single-tooth implants, 2 types of reconstructions were fabricated: a directly veneered one-piece zirconia abutment/crown (control) and a directly veneered fluorescent hybrid zirconia abutment/crown (test). Spectrophotometric assessment was performed: prior to abutment insertion (WA), at abutment try-in (A), at the try-in of the final crowns (C). Color differences (ΔE) were assessed compared to the gingiva of natural teeth (T) and between the reconstructions. RESULTS: At abutment try-in, ΔE values were 8.49 ± 3.59 for AControl and 8.27 ± 4.03 for ATest compared to T. At crown insertion, ΔE values were 7.61 ± 4.03 for CControl and 8.32 ± 3.57 for CTest compared to T. The difference in ΔE values between AControl and ATest was 0.23 ± 2.54 (P = .37), whereas the difference in ΔE values between CControl and CTest was -0.66 ±3.45 (P = .48). For all cases with a mucosal thickness ≤2 mm, the comparison between CControl and CTest was significant in favor of the control group (P = .03). CONCLUSIONS: Both types of reconstructions were similar in terms of esthetics. Incases with a mucosal thickness of <2 mm, the soft tissue discoloration compared to the natural gingiva was more pronounced for the fluorescent hybrid zirconia reconstructions.