1,720,985 research outputs found
Preservation of Peri-implant Soft and Hard Tissues Using Platform Switching of Implants Placed in Immediate Extraction Sockets : A Proof-of-Concept Study with 12- to 36-month Follow-up
No full textPURPOSE: The purpose of this article is to evaluate the soft and hard tissue response to immediately loading implants. In addition, the soft tissue response to a transmucosal abutment that is narrower than the implant platform was assessed.
MATERIALS AND METHODS: Ten consecutive hopeless teeth in the anterior maxilla without compromised bone tissue were enrolled. The infection control phase of periodontal therapy was completed. Immediately after tooth extraction, an implant was placed with a 6 mm platform diameter. A provisional 4 mm diameter transmucosal abutment was connected and a provisional crown was adapted and adjusted for non functional immediately loading. Three months following implant placement, definitive prosthetic rehabilitation was performed. At the time of prosthesis insertion (baseline) and every six months there after, radiographic assessments, pocket probing depths (PPD), recession (REC) and papilla height (PH) were measured. An image analysis software application was used to compare the radiographic bone remodeling at the mesial and distal aspects of the implants. The statistical significance was analyzed by the Student’s t-test with p<0.05.
RESULTS: Nine patients with ten sites were treated. Mean follow up time was 22 months with a range of 36 to 18 months. All the 10 implants were osseointegrated .
Software analysis of radiographic films showed a bone resorption of 0.78 mm (SD: 0,3690). The mean values were statically significant (p≤ 0,005) using a mean reference value of 1.1 mm.
PPD did not exceed 3 mm in any site (average: 2.8 mm). REC gain mean value was 0.2 mm and PH gain mean value was 0.25 mm.
CONCLUSIONS: Within the limit of this study, the data suggests that immediately loading with Platform Switching seems provide peri-implant hard tissue stability, with a consequent soft tissue stable profile
Histological features of peri-implant bone subjected to overload
No full textPurpose: The aim of this review has been to investigate the histological findings of bone structure surrounding implants subjected to excessive load. Materials and methods: Clinical and pre-clinical histological studies that observed overloaded intraoral implants were included. Results: All included studies (n = 15) were conducted on animals. Most of them failed to find pathological alteration in the microstructure of bone surrounding overloaded implants. Overload and infection alone may induce bone loss, but related lesions have different and peculiar features. Conclusions: The different histological features observed around implants subjected to overload or to ligature-induced peri-implantitis may indicate a specific pathogenetic mechanism for overload or infection-induced loss of osseointegration. The clinical significance of these findings should be confirmed in human studies
Vertical ridge augmentation around implants using e-PTFE titanium-reinforced membrane and deproteinized bovine bone mineral (bio-oss) : a case report
No full textThe aim of this case report was to evaluate the ability of Bio-Oss used together with an expanded polytetrafluoroethylene, titanium-reinforced membrane to restore a vertical bone defect. Bio-Oss served as a filler material. After the membrane was removed, screw-type implants were placed. During this phase, cylindric bone samples were retrieved from the augmented area for histologic examination. The biopsy samples were composed of low-density trabecular bone with numerous interspersed graft particles. Clinical and histologic results demonstrated that this surgical technique could be a successful and predictable procedure for rebuilding a resorbed ridge to place implants.
PMID: 16939017 [PubMed - indexed for MEDLINE
Tooth as graft material: Histologic study
Full text linkBackground: An effective regenerative protocol is key to reestablish and maintain the hard and soft tissue dimensions over time. The choice of the graft material and its properties also could have an impact on the results. To prevent alveolar ridge dimensional changes, since numerous graft materials have been suggested and in the past years, a growing interest in teeth material has been observed as a valuable alternative to synthetic biomaterials. Aim: The aim of the study was to explore the histomorphometric outcomes of tooth derivative materials as used as bone substitute material in socket preservation procedure. Methods: After alveolar socket preservation (ASP) procedures using autologous demineralized tooth as graft material prepared by means of an innovative device, was evaluated. A total of 101 histological samples, from 96 subjects, were analyzed by evaluating the total amount of bone (BV), residual tooth material (residual graft, TT), and vital bone (VB). The section from each sample was then split in nine subsections, resulting in 909 subsections, to allow statistical comparison between the different areas. Results: It was not noticed a statistically significant difference between maxillary and mandibular sites, being the amount of VB in upper jaw sites 37.9 ± 21.9% and 38.0 ± 22.0% in lower jaw sites and the amount of TT was 7.7 ± 12.2% in maxilla and 7.0 ± 11.1% in mandibles. None of the other considered parameters, including defect type and section position, were statistically correlated to the results of the histomorphometric analysis. Conclusions: ASP procedure using demineralized autologous tooth-derived biomaterial may be a predictable procedure to produce new vital bone potentially capable to support dental implant rehabilitation
Socket grafting in the posterior maxilla reduces the need for sinus augmentation
No full textThis study compared the dimensional alterations, the need for sinus floor elevation, and the histologic wound healing of augmented and nonaugmented alveolar sockets. Sixteen human extraction sockets were either grafted or left untreated. At baseline and 3 and 6 months postextraction, alveolar ridge alterations were evaluated; at 3, 6, and 9 months, histologic analyses were conducted. Implant placement with or without sinus floor augmentation was decided at 6 months. Three of eight patients in the control group underwent sinus floor augmentation compared to one of six in the experimental group. The alveolar ridge augmentation procedure presented here increases the possibility of inserting implants without the need for a sinus augmentation procedure
Sinus lift using a nanocrystalline hydroxyapatite silica gel in severely resorbed maxillae: histological preliminary study
No full textPurpose: The aim of this preliminary study was to evaluate histologically a nanocrystalline hydroxyapatite silica gel in maxillary sinus floor grafting in severely resorbed maxillae. Materials and Methods: A total of 16 consecutive patients scheduled for sinus lift were recruited during this study. Patients were randomly divided in two groups, eight patients each. In both groups, preoperative residual bone level ranged between 1 and 3 mm (mean value of 2.03 mm). No membrane was used to occlude the buccal window. Second surgery was carried out after a healing period of 3 months in Group 1 and 6 months in Group 2. Using a trephine bur, one bone specimen was harvested from each augmented sinus and underwent histological and histomorphometric analysis. Results: Histological analysis showed significant new bone formation and remodeling of the grafted material. In the cores obtained at 6 months, regenerated bone, residual NanoBone, and bone marrow occupied respectively 48 +/- 4.63%, 28 +/- 5.33%, and 24 +/- 7.23% of the grafted volume. In the specimens taken 3 months after grafting, mean new bone was 8 +/- 3.34%, mean NanoBone was 45 +/- 5.10%, and mean bone marrow was 47 +/- 6.81% of the bioptical volume. Conclusions: Within the limits of this preliminary prospective study, it was concluded that grafting of maxillary sinus using nanostructured hydroxyapatite silica gel as only bone filler is a reliable procedure also in critical anatomic conditions and after early healing period
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
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