Guided surgery and immediate loading: A digital approach

Wismeyer, D. [Promotor

Resolving Holliday Junctions with Escherichia coli UvrD Helicase

The Escherichia coli UvrD helicase is known to function in the mismatch repair and nucleotide excision repair pathways and has also been suggested to have roles in recombination and replication restart. The primary intermediate DNA structure in these two processes is the Holliday junction. UvrD has been shown to unwind a variety of substrates including partial duplex DNA, nicked DNA, forked DNA structures, blunt duplex DNA and RNA-DNA hybrids. Here, we demonstrate that UvrD also catalyzes the robust unwinding of Holliday junction substrates. To characterize this unwinding reaction we have employed steady-state helicase assays, pre-steady-state rapid quench helicase assays, DNaseI footprinting, and electron microscopy. We conclude that UvrD binds initially to the junction compared with binding one of the blunt ends of the four-way junction to initiate unwinding and resolves the synthetic substrate into two double-stranded fork structures. We suggest that UvrD, along with its mismatch repair partners, MutS and MutL, may utilize its ability to unwind Holliday junctions directly in the prevention of homeologous recombination. UvrD may also be involved in the resolution of stalled replication forks by unwinding the Holliday junction intermediate to allow bypass of the blockage

Crestal bone changes around implants with implant-abutment connections at epicrestal level or above: Systematic review and meta-analysis

Purpose: The aim of this systematic review and meta-analysis was to evaluate crestal bone changes around implants when placing the implant-abutment connection at the crestal bone level or above. Materials and Methods: Medline (Pubmed), EMBASE, and Cochrane Library up to January 2014 were electronically and hand searched for any publications that evaluated radiographic crestal bone changes around nonsubmerged, rough-surfaced implants placed in healed sites in humans and loaded for a minimum of 1 year. Results: The search yielded 1,122 publications; 1,106 could not be included. After 16 full-text articles were read and subjected to inclusion and exclusion criteria, four were included. The mean difference was -0.29 mm (95% CI, -0.58 mm to -0.01 mm). Heterogeneity between studies was observed (I2 = 95%). Significantly more crestal bone change was seen in the epicrestal implant-abutment (bone level) connection group when compared to implants with the prosthetic connection above the crestal bone level (tissue level) (P < .00001). Conclusion: Dental implants at bone level show significantly less crestal bone change after 1 year of loading than tissue-level implants

Computer-guided implant placement: 3D planning software, fixed intraoral reference points, and CAD/CAM technology. A case report

The aim of this article is to explain the use of a computer-aided three-dimensional planning protocol in combination with previously placed mini-implants and computer-aided design/computer-assisted manufacture (CAD/CAM) technology to restore a completely edentulous patient. Mini-implants were used to establish a setup for computerized tomographic imaging and a surgical template. The software and its three-dimensional simulation allowed the authors to plan ideal implant placement, digitally integrating the future prosthetic and anatomic situations to design the definitive superstructure. The CAD/CAM superstructure is produced digitally with a precise fit and occlusion and good esthetics, and is placed immediately after surgery