Randomized controlled pilot study comparing small buccal defects around dental implants treated with a subepithelial connective tissue graft or with guided bone regeneration.

AIM: To compare subepithelial connective tissue grafts (SCTG) versus guided bone regeneration (GBR) for the treatment of small peri-implant dehiscence defects in terms of profilometric (primary outcome), clinical, and patient-reported outcome measures (PROMs). METHODS: Sixteen patients who presented with small buccal bone dehiscences (≤3 mm) following single implant placement were recruited. Following implant placement, buccal bone defect sites were randomly treated either with a SCTG or GBR. Six patients who lacked bone dehiscences after implant placement were assigned to a negative control. Transmucosal healing was applied in all patients. Patients were examined prior (T1) and after (T2) implant placement, at suture removal (T3), at implant impression (T5), at crown delivery (T6), and 12 (T7) months after crown delivery. Measurements included profilometric outcomes, marginal bone levels, buccal bone and soft tissue thickness, PROMs, and clinical parameters. All data were analyzed descriptively. RESULTS: The median changes in buccal contour as assessed by profilometric measures between T1 and T5 showed a decrease of 1.84 mm for the SCTG group and 1.06 mm for the GBR group. Between T2 and T7, the median change in the buccal contour amounted to 0.45 mm for SCTG and -0.94 mm (=loss) for GBR. Patients' pain perception tended to be higher in SCTG than in GBR. All peri-implant soft tissue parameters showed healthy oral tissues and no clinically relevant differences between groups. CONCLUSION: Within the limitations of this pilot study, treating small peri-implant dehiscence defects with a SCTG might be a viable alternative to GBR. The use of a SCTG tended to result in more stable profilometric outcomes and comparable clinical outcomes to GBR. However, patient-reported outcome measures tended to favor GBR.

Group 2 ITI Consensus Report: Technological developments in implant prosthetics.

OBJECTIVES: Group-2 reviewed the scientific evidence in the field of «Technology¼. Focused research questions were: (1) additive versus subtractive manufacturing of implant restorations; (2) survival, complications, and esthetics comparing prefabricated versus customized abutments; and (3) survival of posterior implant-supported multi-unit fixed dental prostheses. MATERIALS AND METHODS: Literature was systematically screened, and 67 publications could be critically reviewed following PRISMA guidelines, resulting in three systematic reviews. Consensus statements were presented to the plenary where after modification, those were accepted. RESULTS: Additively fabricated implant restorations of zirconia and polymers were investigated for marginal/internal adaptation and mechanical properties without clear results in favor of one technology or material. Titanium base abutments for screw-retained implant single crowns compared to customized abutments did not show significant differences concerning 1-year survival. PFM, veneered and monolithic zirconia implant-supported multi-unit posterior fixed dental prostheses demonstrated similar high 3-year survival rates, whereas veneered restorations exhibited the highest annual ceramic fracture and chipping rates. CONCLUSIONS: For interim tooth-colored implant single crowns both additive and subtractive manufacturing are viable techniques. The clinical performance of additively produced restorations remains to be investigated. Implant single crowns on titanium base abutments show similar clinical performance compared to other type of abutments; however, long-term clinical data from RCTs are needed. The abutment selection should be considered already during the planning phase. Digital planning facilitates 3D visualization of the prosthetic design including abutment selection. In the posterior area, monolithic zirconia is recommended as the material of choice for multi-unit implant restorations to reduce technical complications.

IgA nephropathy associated with dental nickel alloy sensitization.

We report a patient with documented IgA nephropathy in whom microscopic hematuria, proteinuria, and hypertension first occurred after placement of nickel alloy base dental crowns. Progressive proteinuria culminating in nephrotic-range proteinuria occurred parallel to increased nickel placement and dramatically resolved following nickel alloy removal. That immunologic alterations occur as a result of nickel exposure has already been suggested by the common occurrence of nickel contact dermatitis, often exacerbated by intraoral nickel placement, increased carcinogenesis in nickel refinery workers, and animal models of nickel-associated carcinogenesis. Our patient may represent an example of nickel-induced sensitization and associated IgA glomerulopathy. Further study of patients with immune-mediated glomerulopathy with attention to dental nickel exposure appears indicated.

Association of double-stranded DNA fragments into multistranded DNA structures.

We have previously observed that double-stranded DNA fragments containing a tract of the tandemly repeated sequence poly(CA). poly(TG) can associate in vitro to form stable complexes of low electrophoretic mobility, which are recognized with high specificity by proteins HMG1 and HMG2. The formation of such complexes has since been observed to depend on interactions of DNA with polypropylene surfaces, with the suggestion that the formation of low mobility complexes might be the result of strand dissociation followed by misaligned reassociation of the repetitive sequences. The data presented here show that at high ionic strength the interactions of DNA with polypropylene are sufficiently strong for DNA to remain bound to the polypropylene surface, which suggests that DNA might also be involved in interactions with hydrophobic molecules in vivo. Under such conditions, low-mobility complexes are found only in the material adsorbed to the polypropylene surface, and all DNA fragments are able to form low-mobility structures, whether or not they contain repetitive sequences. Preventing the separation of strands by ligating hairpin loop oligonucleotides at both ends of the fragments does not prevent the formation of low-mobility complexes. Our results suggest two different pathways for the formation of complexes. In the first, dissociation is followed by misaligned reassociation of repetitive sequences, yielding duplexes with single-stranded end regions that associate to form multimeric complexes. In the second, repetitive as well as nonrepetitive DNA molecules bound to polypropylene adopt a conformation with locally unwound regions, which allows interactions between neighboring duplexes adsorbed on the surface, resulting in the formation of low-mobility complexes.