1,720,996 research outputs found
Longitudinal analysis of treatment of peri-implant disease utilizing magnetic resonance frequency and damping capacity analysis.
No full textBackground: Peri-implant disease has the potential to cause loss of implant stability and
subsequent implant failure. Non-invasive, quantitative measures of implant stability offered
by Osstell® and Periotest® devices may have the potential to aid in peri-implant disease
diagnosis and monitoring post-operative healing and implant stability.
Aims: To assess the impact of peri-implantitis therapy on peri-implant parameters and implant stability using both devices. To determine the degree of correlation between devices and if one correlates more superiorly than the other with clinical and radiographic changes post-operatively. To ascertain the most appropriate time to re-evaluate implants following peri-implantitis treatment.
Materials & Methods: A prospective clinical study on a cohort of Dublin Dental
University Hospital subjects who had been diagnosed with peri-implantitis was completed.
Baseline data collection included several clinical and radiographic peri-implant parameters,
as well as ISQ and PTV levels using the Osstell IDX® and Periotest Classic® devices,
respectively. Patients were assigned to receive either non-surgical therapy, resective surgery or regenerative surgery encompassing barrier membranes, Leucocyte-platelet rich fibrin and hard tissue grafting. Follow-up measurements were repeated at 3, 6 and 12-months. SPSS® software was used for statistical analysis. The statistical significance of changes in peri-implant parameters and implant stability over 12-months, as well as treatment subgroup
analysis, was determined using One-Way ANOVA or Kruskal-Wallis H tests. Pearson and
Spearman correlation coefficients were used to test correlation between changes in peri-implant parameters and implant stability and between Osstell® and Periotest® devices.
Results: 26 subjects were included with a total of 85 implants receiving treatment.
Statistically significant improvements in all peri-implant and radiographic parameters over
the 12-months were found, with the exception of keratinized tissue levels. Improved implant
stability as indicated by increased ISQ and decreased PTV levels, was observed but changes
were not significant. The greatest clinical improvements were seen for implants which
received hard tissue grafting, with a mean bone gain of 1.13mm (SD 1.58), mean probing
depth reduction of 3.00mm (SD 3.54) and mean attachment level gain of 2.75mm (SD 1.99)
at 12-months. Strong correlations were found in the hard tissue grafting subgroup between
changes in mean ISQ levels and deepest probing depths (r=-.743, p=.000), average probing
depths (r=-.697, p=.000) and clinical attachment levels (r=-.717, p=.000) at 12-months.
Moderate correlations were found in the hard tissue grafting subgroup between changes in
mean PTV levels and average probing depths (r=.585, p=.028) and clinical attachment levels
(r=.582, p=.022) at 12-months. Strong correlations were found between Osstell® and
Periotest® devices at each study timepoint, with the strongest correlation found at 12-months(r=-.808, p=.000; mean ISQ 66.67 Vs mean PTV -2.47). Regenerative subgroups which
received a barrier membrane (r=-.801, p=.005) and hard tissue graft (r=-.951, p=.000) yielded strong negative correlations between devices at 12-months.
Conclusions: All treatment modalities resulted in improved clinical and radiographic periimplant parameters over 12-months. Implant stability improved post-treatment, as indicated by increased ISQ and decreased PTV levels, however, such changes were not statistically significant. A high degree of correlation was found between devices when used to monitor changes in implant stability, particularly following regenerative interventions. While both devices may be used as complimentary diagnostic tools in quantifying post-operative changes following peri-implantitis treatment, Osstelltm correlated more accurately with changes in clinical and radiographic parameters than Periotesttm. Within the limitations of this study, 12-months appears to be the most appropriate time to re-evaluate the stability of implants treated for peri-implant disease
A quasi-experimental study comparing the effects of L-PRF and white porous titanium granules on the preservation of the buccal bone following immediate implant placement
No full textThe aim of this quasi-experimental study was to compare the effects of leucocyte and platelet-rich fibrin (L-PRF) and white porous titanium granules (WPTG) on the preservation of the buccal bone plate following immediate implant placement. It also attempted to identify the possible variables affecting this remodelling.
35 implants were placed in the anterior maxilla immediately following tooth extraction and clinical measurements were made to determine the dimensions of the alveolar ridge and the void between the implant and the buccal bone. The voids were then grafted with either L-PRF or WPTG. These measurements were repeated at 2nd stage surgery following 4 months of submerged healing.
Both grafting protocols resulted in clinically acceptable results and a 100% survival rate, at least in the short term. WPTG was superior to L-PRF resulting in greater buccal bone thickness and buccal bone height at 4 months, although the differences were not statistically.
Statistical analysis determined the gap width, the buccal bone thickness and the horizontal buccal bone dimension were the main indicators for the ridge width at re-entry. It was also demonstrated that specific socket characteristics were key determinants of the magnitude of alveolar ridge remodelling, in particular gap width and gap depth.
In conclusion, the grafting protocols employed in this study can be considered successful following immediate implant placement in the anterior maxilla. However, WPTG appears to be superior to L-PRF in preservation of the buccal bone plate
Measurement of dental implant stability by Osstell and Periotest at three different time points: Correlation between the two devices and comparison with clinical characteristics
No full textAbstract
Measurement of dental implant stability by Osstell and Periotest at three different time points: Correlation between the two devices and comparison with clinical characteristics.
Background: Implant stability is a fundamental feature of osseointegration and success of dental implant therapy. Objective and non-invasive measurement devices have been developed to measure implant stability. The purpose of this study was to enhance our understanding of two different implant stability measurement devices, the Osstell mentor and Periotest. Aims: To determine the level of correlation between implant stability measurements of these two devices. To evaluate the influence of a range of clinical characteristics on the values obtained with these measurement devices. To establish a
normative range for Zimmer Biomet dental implants with an Osseotite surface.
Materials & Methods: A prospective cohort study was undertaken to evaluate stability of dental implants at three different timepoints. Measurements were recorded at implant placement (T1), implant exposure (T2) and implant loading (T3). A range of clinical data was collected including details of the patient demographics, implant surgery, site and fixture features. From September 2018 to July 2020, stability measurements and clinical characteristics were recorded for 29 patients and 68 dental implants at T1, subsequent stability measurements were recorded for 67 implants at T2 and 42 implants at T3. Statistical analysis was performed with IBM SPSS software V26. Data analysis included descriptive statistics and a Spearman?s Rho test to evaluate correlation between values obtained with measurement devices. A Mann-Whitney or Krushal Wallis test was performed to compare stability measurements with clinical characteristic groups. Results: A weak/moderate correlation was observed between mean ISQ and Periotest values at T1, T2 and T3, (r = -0.279, p=0.021), (r = -0.368, p=0.002) and (r = -0.342, p=0.026) respectively. The mean ISQ value was 70.8(SD 7.40) at implant placement, 70.2(SD 8.51) at implant exposure and 72.4(SD 5.42) at implant loading. The mean Periotest value was -3.79 (SD 4.65) at implant placement, -4.60(SD 2.98) at implant exposure and -5.55(SD 2.14) at implant loading. The range of ISQ values observed was 30-89 ISQ at implant placement and 61-82 ISQ at implant loading. The Periotest values ranged from 29 to -8 at 1st stage surgery and -2 to -8 at implant loading. A single dental implant failed shortly after 2nd stage surgery for an overall success rate of 98% during the study timeline. The failed implant had a mean ISQ of 49 and Periotest value of 3 at 2nd stage surgery. There were no radiographic or clinical signs to indicate implant failure at this stage. Conclusions: There is a weak/moderate level of correlation between values recorded with these measurement devices from implant placement to implant loading. For both the Osstell and PeriotestTM a narrowing of stability values is observed from implant placement to fit of prosthesis. The stability values observed in the mandible are higher with the Osstell and lower with the PeriotestTM indicating greater implant stability in the mandible compared to the maxilla. Beyond this finding no clinical characteristic demonstrated a substantial influence on stability measurements of either device. Despite the weak correlation between the values generated by the two devices we would suggest that these devices may be beneficial as adjuncts to standard clinical practice and as instruments that can predict future implant failure. Finally, we propose a normative range of 61-82 ISQ as measured by the Osstell mentor device for osseointegrated Zimmer Biomet dental implants with an Osseotite surface
A clinical and biochemical investigation on the effects of non-surgical periodontal treatment of chronic and aggressive periodontitis. A comparative study.
No full textAlthough Chronic (CP) and Aggressive Periodontitis (GAP) were classified in the 1999 world workshop and specific defining characteristics have been identified in this classification, clinically it is difficult to differentiate between the two groups. Additionally, earlier studies have extensively investigated how chronic periodontitis patients respond to non-surgical treatment, but only very few studies investigated this same response for GAP patients. Comparative studies are not only limited and underpowered but also heterogeneous in the way the two periodontitis groups are diagnosed. The aim of the study was to test the hypothesis of a different clinical and immunological response to non-surgical therapy in subjects with aggressive periodontitis when compared to the response of subjects with chronic periodontitis. Following examination, patients were diagnosed with either chronic periodontitis or generalized aggressive periodontitis. During the recruitment of patients, if the patient fulfilled the inclusion criteria, oral hygiene instructions along with smoking cessation advice was given. In suitable patients who agreed to participate in the study, a consent form was given for signing and a numerical code was assigned to them. In the same visit GCF samples were collected. The treatment commenced by performing scaling and root debridement, two quadrants at a time beginning with the right side quadrants. An initial recall visit was scheduled 6 weeks following therapy for oral hygiene reinforcement and re-evaluation was performed 3 months following the initial treatment. Two operators carried out the treatments and collected the specified data. The clinical measurements were done by one calibrated examiner to reduce any inter examiner bias. The GCF samples were collected preoperatively from the deepest pocket in each patient by using the gingival fluid collection strips also known as Perio-paper from the deepest pocket. Postoperative samples were also collected from the same site 3 months following completion of treatment. Analysis of the samples was done by using BD (CBA) Human Inflammatory Cytokine Kit and testing for IL-8, IL-6, IL-1?, IL-10, IL-12p70, TNF?. Dependent t-tests (or the non-parametric equivalent) were used to compare the response to treatment within the same group, while independent t-test (or the non-parametric equivalent) were used to compare the difference in response to treatment in-between groups. Overall, both AP and CP patients showed notable improvements in clinical parameters in response to therapy and no significant differences were found between GAP and CP subjects. Furthermore, immunological profiles did not show significant differences between the two groups. However, clinical attachment loss was observed in the deep sites of the CP group. Comparing the two groups, no significant differences were observed between GAP and CP at baseline and 3months re-evaluation, apart from the significantly better CALs (Clinical Attachment Levels) in the GAP group following treatment. At baseline and in moderately deep pockets, CAL was higher in the CP group than in the GAP. Following treatment there was a statistical significant attachment gain for both groups but more marked in CP patients. No CAL gain was observed in the shallow and deep sites of the CP patients. Following the exclusion of smokers in both groups and on a patient level, CALs showed similar improvement with no statistical difference between groups. Immunological investigations demonstrated increased levels of IL-1?; in GAP as it was recorded to be twice as high as the concentration of IL-1?; in the CP group. However, both groups showed significant reduction after treatment with no statistical significant difference between CP and GAP samples
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe 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
Get PDF“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
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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