Esthetic and Clinical Performance of Implant-Supported All-Ceramic Crowns Made with Prefabricated or CAD/CAM Zirconia Abutments: A Randomized, Multicenter Clinical Trial

Abstract

Patients' esthetic expectations are increasing, and the options of the prosthetic pathways are currently evolving. The objective of this randomized multicenter clinical trial was to assess and compare the esthetic outcome and clinical performance of anterior maxillary all-ceramic implant crowns (ICs) based either on prefabricated zirconia abutments veneered with pressed ceramics or on CAD/CAM zirconia abutments veneered with hand buildup technique. The null hypothesis was that there is no statistically significant difference between the 2 groups. Forty implants were inserted in sites 14 to 24 (FDI) in 40 patients in 2 centers, the Universities of Bern and Geneva, Switzerland. After final impression, 20 patients were randomized into group A, restored with a 1-piece screw-retained single crown made of a prefabricated zirconia abutment with pressed ceramic as the veneering material using the cut-back technique, or group B using an individualized CAD/CAM zirconia abutment (CARES abutment; Institut Straumann AG) with a hand buildup technique. At baseline, 6 mo, and 1 y clinical, esthetic and radiographic parameters were assessed. Group A exhibited 1 dropout patient and 1 failure, resulting in a survival rate of 94.7% after 1 y, in comparison to 100% for group B. No other complications occurred. Clinical parameters presented stable and healthy peri-implant soft tissues. Overall, no or only minimal crestal bone changes were observed with a mean DIB (distance from the implant shoulder to the first bone-to-implant contact) of -0.15 mm (group A) and 0.12 mm (group B) at 1 y. There were no significant differences at baseline, 6 mo, and 1 y for DIB values between the 2 groups. Pink esthetic score (PES) and white esthetic score (WES) values at all 3 examinations indicated stability over time for both groups and pleasing esthetic outcomes. Both implant-supported prosthetic pathways represent a valuable treatment option for the restoration of single ICs in the anterior maxilla ( ClinicalTrials.gov NCT02905838).

The clinical performance of all‐ceramic implant‐supported single crowns: A systematic review and meta‐analysis

“…The "Cochrane Collaboration's tool for assessing risk of bias in randomized trials" was used to evaluate the RCTs in this systematic review (Bömicke et al, 2017;Hosseini, Worsaae, Schiodt, & Gotfredsen, 2011;Paolantoni et al, 2016;Payer et al, 2015;Thoma, Brandenberg, Fehmer, Buchi, et al, 2016;Wittneben et al, 2017) (Supporting information Table S2). All RCTs provided enough information for the evaluation of any incomplete outcome data and selective reporting.…”

“…(b) Forest plot of the estimated annual event rate (per 100 years) for chipping from investigations with a mean follow-up of equal/more than 8 years TA B L E 6 Estimated event rates per 100 crown years and estimated technical complication rates after 5 years performed in four investigations (Bömicke et al, 2017;Payer et al, 2015;Thoma, Brandenberg, Fehmer, Buchi, et al, 2016;Wittneben et al, 2017); information on allocation concealment was given in three studies (Bömicke et al, 2017;Hosseini et al, 2011;Payer et al, 2015). Random sequence generation has been F I G U R E 4 (a) Forest plot of the estimated annual event rate (per 100 years) for chipping from investigations with a mean follow-up of less than 8 years.…”

Biological effect of the abutment material on the stability of peri‐implant marginal bone levels: A systematic review and meta‐analysis

“…In the six remaining studies, one used gold (Gallucci, Grutter, Chuang, & Belser, 2011), one zirconia (Thoma et al, 2016) and one alumina (Chen, Nang, Wang, & Luo, 2008) as control abutments, two compared different fabrication methods of ceramic abutments (Schepke, Meijer, Kerdijk, Raghoebar, & Cune, 2017;Wittneben et al, 2017), and one compared two different impression protocols for ceramic abutments (Erhan Comlekoglu, Nizam, & Comlekoglu, 2018). In these six studies, each arm was considered independent and evaluated together with the selected case series when evaluating the behaviour of the abutment material different from titanium.…”

Influence of the fixed implant‐supported provisional phase on the esthetic final outcome of implant‐supported crowns: 3‐year results of a randomized controlled clinical trial

“…2 To achieve predictable and long-term stable outcomes backward-driven treatment planning including the evaluation of prosthetic and surgical risk factors is essential. The rehabilitation of esthetic sites aiming a prosthetic pleasing result is often challenging as ideal overall esthetic outcomes are depended on both pink and white esthetics.…”