Immediate versus delayed implant placement after anterior single tooth extraction: the timing randomized controlled clinical trial

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Immediate vs. Delayed Implant Placement after Anterior Single Tooth Extraction: The Timing Randomised Controlled Clinical Trial.

to compare need for bone augmentation, surgical complications, periodontal, radiographic, aesthetic and patient reported outcomes in subjects receiving implant placement at the time of extraction (IMI) or 12 weeks thereafter. METHODS: Subjects requiring single tooth extraction in the anterior and premolar areas were recruited in 7 private practices. Implant position and choice of platform were restoratively driven. Measurements were performed by calibrated and masked examiners. RESULTS: IMI was unfeasible in 7.5% of cases. 124 subjects were randomized. One implant was lost in the IMI group. IMI required bone augmentation in 72% of cases compared with 43.9% for delayed (P=0.01), while wound failure occurred in 26.1% and 5.3% of cases, respectively (P=0.02). At 1 year, IMI had deeper probing depths (4.1±1.2 mm vs. 3.3±1.1 mm, P<0.01). A trend for greater radiographic bone loss was observed at IMI over the initial 3-year period (Ptrend<0.01). Inadequate pink aesthetic scores were obtained in 19% of delayed and in 42% of IMI implant cases (P=0.03). No differences in patient reported outcomes were observed. CONCLUSIONS: Immediate implant placement should not be recommended when aesthetics are important, IMI should be limited to selected cases. Longer follow-up is needed to assess differences in complication rates. This article is protected by copyright. All rights reserved

Microbial colonization patterns predict the outcomes of surgical treatment of infrabony defect

Aim: To explore the impact of bacterial load and microbial colonization patterns on the clinical outcomes of periodontal surgery at deep intrabony defects. Materials and Methods: One hundred and twenty-two patients with advanced chronic periodontitis and at least one intrabony defect of 43mm were recruited in 10 centres. Before recruitment, the infection control phase of periodontal therapy was completed. After surgical access and debridement, the regenerative material was applied in the test subjects, and omitted in the controls. At baseline and 1 year following the interventions, clinical attachment levels (CAL), pocket probing depths (PPD), recession (REC), full-mouth plaque scores and full-mouth bleeding scores were assessed. Microbial colonization of the defect-associated pocket was assessed using a DNA\u2013DNA checkerboard analysis. Results: Total bacterial load and counts of red complex bacteria were negatively associated with CAL gains 1 year following treatment. The probability of achieving above median CAL gains (43 mm) was significantly decreased by higher total bacterial counts, higher red complex and T. forsythensis counts immediately before surgery. Conclusions: Presence of high bacterial load and specific periodontal pathogen complexes in deep periodontal pockets associated with intrabony defects had a significant negative impact on the 1 year outcome of surgical/regenerative treatmen

Live Imaging of Xwnt5A-ROR2 Complexes

Secreted molecules of the Wnt family regulate key decisions in embryogenesis and adult tissue homeostasis by activating a complex network of Wnt signaling pathways. Although the different branches of Wnt signaling have been studied for more than 25 years, fluorophore tagged constructs for live cell imaging of Wnt molecules activating the Wnt/β-catenin pathway have become available only recently. We have generated a fluorophore tagged Wnt construct of the Xenopus Wnt5a protein (Xwnt5A) with the enhanced green fluorescent protein (EGFP), Xwnt5A-EGFP. This construct activates non-canonical Wnt pathways in an endocytosis dependent manner and is capable of compensating for the loss of endogenous Xwnt5A in Xenopus embryos. Strikingly, non-canonical Wnt pathway activation was restricted to short-range signaling while an inhibitory effect was observed in transwell cell cultures taken as long-range signaling model sytem. We used our Xwnt5A-EGFP construct to analyze in vivo binding of Wnt5A to its co-receptor ROR2 on the microscopic and on the molecular level. On the microscopic level, Xwnt5A-EGFP clusters in the membrane and recruits ROR2-mCherry to these clusters. Applying dual-colour dual-focus line-scanning fluorescence correlation spectroscopy on dorsal marginal zone explants, we identified membrane tethered Xwnt5A-EGFP molecules binding to ROR2-mCherry molecules. Our data favour a model, in which membrane-tethered Wnt-5A recruits ROR2 to form large ligand/receptor clusters and signals in an endocytosis-dependent manner

The significance of angiogenesis in guided bone regeneration: A case report of a rabbit experiment

A dome-shaped bioresorbable membrane was fixed to the wounded rabbit calvaria and filled with a bioresorbable fibre conglomerate. After 4 weeks, the histologic preparation revealed an intimate spatial and temporal correlation between newly formed blood vessels and de novo extraskeletal bone formation. These observations emphasize the significance of angiogenesis in guided bone generation. © Munksgaard 1997.link_to_subscribed_fulltex

Functional conservation of Nematostella Wnts in canonical and noncanonical Wnt-signaling

Summary Cnidarians surprise by the completeness of Wnt gene subfamilies (11) expressed in an overlapping pattern along the anterior-posterior axis. While the functional conservation of canonical Wnt-signaling components in cnidarian gastrulation and organizer formation is evident, a role of Nematostella Wnts in noncanonical Wnt-signaling has not been shown so far. In Xenopus, noncanonical Wnt-5a/Ror2 and Wnt-11 (PCP) signaling are distinguishable by different morphant phenotypes. They differ in PAPC regulation, cell polarization, cell protrusion formation, and the so far not reported reorientation of the microtubules. Based on these readouts, we investigated the evolutionary conservation of Wnt-11 and Wnt-5a function in rescue experiments with Nematostella orthologs and Xenopus morphants. Our results revealed that NvWnt-5 and -11 exhibited distinct noncanonical Wnt activities by disturbing convergent extension movements. However, NvWnt-5 rescued XWnt-11 and NvWnt-11 specifically XWnt-5a depleted embryos. This unexpected ‘inverse’ activity suggests that specific structures in Wnt ligands are important for receptor complex recognition in Wnt-signaling. Although we can only speculate on the identity of the underlying recognition motifs, it is likely that these crucial structural features have already been established in the common ancestor of cnidarians and vertebrates and were conserved throughout metazoan evolution

Effect of bioresorbable fibres (Polyfibre) and a bioresorbable foam (Polyfoam) on new bone formation. A short term experimental study on the rabbit skull

The aim of the study was to evaluate two bioresorbable polylactic acid (PLA) filler materials in a guided bone regeneration (GBR) model system. The first was Polyfibre, a fibrous PLA filler material. Polyfoam, the second material tested, consisted of a spongy PLA filler material. In each group there were eight rabbits. In test rabbits a flap was raised uncovering the calvaria. A hemispherical PLA dome was filled with Polyfibre or Polyfoam material and periphereal blood and anchored onto the calvaria. Eight rabbits with the same domes, filled with blood alone, served as controls. The rabbits were sacrificed at 1 or 2 months. Histomorphometric measurements of regenerated total tissue volume, bone height and bone volume were carried out in undecalcified sections under a light microscope. At 1 month the totally filled volume attained 87% (range 82-91) in the fibre group, including 25% (23-27) fibres, 87% (85-95) in the foam group, including 15% (15-16) foam, and 55% (16-100) in the controls. The volume of mineralized bone was 12% (7-15) in the fibre group, 15% (12-18) in the foam group and 6% (1-11) in control domes. Bone height attained 48% (27-79) in the fibre group, 37% (31-58) in the foam group and 45% (14-67) in the control group. At 2 months, tissue volume attained 86% (85-87) including 26% (22-29) fibres, bone volume attained 13% (7-21) and bone height attained 56% (42-78) in the Polyfibre group. In the Polyfoam group, they were 83% (55-99) including 18% (15-19) foam, 13% (7-24) and 49% (29-74). In control domes, tissue volume was 82% (35-100), bone volume 20% (9-27) and bone height 86% (60-100). The Polyfibre and Polyfoam material was excellently integrated. No adverse reactions were found in the surrounding tissues. Direct bone apposition was observed onto the material. In conclusion, Polyfibre and Polyfoam material had a positive effect on initial bone and tissue formation but was a hindrance to increasing tissue volume, bone volume or bone height at 2 months compared to control specimens. The Polyfibre and Polyfoam material provoked no adverse reactions in the surrounding tissues and allowed for extensive angiogenesis

Effects of a single topical doxycycline administration adjunctive to mechanical debridement in patients with persistent/recurrent periodontitis but acceptable oral hygiene during supportive periodontal therapy

OBJECTIVES: To evaluate the efficacy of a slow release doxycycline gel (SRD) adjunctively administered to non-surgical therapy in subjects with recurrent or persistent periodontitis but acceptable oral hygiene during supportive periodontal care. MATERIAL and METHODS: In this single blind, parallel group, multicentre study, 202 of 203 recruited periodontal maintenance subjects with recurrent or persistent periodontitis were randomly assigned to subgingival ultrasonic/sonic instrumentation (USI) with (test) or without (control) subsequent administration of SRD in all residual periodontal pockets >/=4 mm. Intergroup differences in probing depth, BOP reductions, treatment time, probing attachment levels were evaluated at 3, 6 and 12 months. The primary outcome was the inter-group difference in absolute change of probing pocket depth (PPD) 3, 6 and 12 months after intervention. RESULTS: At baseline, the two groups were comparable. At 3 months, the test group showed a significantly higher decrease in mean probing depth than the control group at 3 months (mean difference = 0.11 mm, 95% CI 0.03-0.19 mm, p = 0.003). Administration of SRD resulted in significantly greater odds of transition of bleeding pockets >/=5 mm to a category of non bleeding sites with PPD /=2 mm) and were exited from the study. No difference in the incidence of adverse events was observed between groups. CONCLUSION: The trial results show that topically administered SRD may provide short-term benefit in controlling inflammation and deep pockets in treated periodontal patients participating in a secondary prevention programme and able to maintain a satisfactory level of oral hygiene.link_to_subscribed_fulltex

Marginal fit of dental restorations and the periodontium in Swiss army recruits | Restaurationsrandschlusse und Parodont bei Schweizer Rekruten.

The present study analyzed the relationship between periodontal health adjacent to filled and unfilled tooth sites in young men (recruits). The status of oral health of 419 Swiss army recruits, aged 19 to 20 years was assessed by determining Plaque Index (PI), Retention Index (RI) and Gingival Index (GI) as well as Pocket Probing Depth (PPD) and Probing Attachment Loss (PAL). In addition, the level of alveolar bone was measured using digitized bite-wing radiographs with an enlargement of 4.5x. Filling margins were assessed and the distance between the alveolar bone crest and the cemento-enamel junction (CEJ) measured to the nearest one tenth of a millimeter. These data were compared with the clinical parameters. A total of 8'050 sites were examined. 765 or 9.5 of the sites in the posterior area were filled. 119 of them showed filling overhangs larger than 0.2 mm. Thus, 1.5 % of the examined sites had a significant overhanging margin. All clinical parameters had greater values at filled than at unfilled sites. The differences were statistically not significant. Even the sites with margins overhanging more than 0.8 mm (n=14) did not show significantly different parameters compared to unfilled sites. The comparison with a similar study involving recruits 11 years earlier assessed that the recruits of 1996 had less and smaller filling overhangs. This, in turn, means that, in Switzerland restorative dentistry in young males has been markedly improved during the 1980's and 1990's.link_to_subscribed_fulltex