75 research outputs found
Histologic analyses of flapless ridge preservation in sockets with buccal dehiscence defects using two alloplastic bone graft substitutes
OBJECTIVES
To investigate whether one of two synthetic bone substitute materials used for ridge preservation in the extraction sockets with buccal dehiscence defects was superior regarding new bone formation and ridge preservation and to compare it to sites left for spontaneous healing.
MATERIALS AND METHODS
In sixteen dogs, P3 and P4 were hemi-sectioned and the respective distal roots were extracted. Following the preparation of a mucoperiosteal flap without vertical releasing incisions, 50% of the buccal bone was carefully removed. The extraction sites were randomly assigned either to a ridge preservation procedure (alloplastic bone substitute material (two test groups)) or to spontaneous healing (control group). Descriptive histology and histomorphometric analyses were performed at healing times of 4, 8, and 16Â weeks. In case of homogeneous variances, the results were analyzed by one-way ANOVA, followed by Tukey's post-hoc test. If inhomogeneous, the data was analyzed using Welch-type ANOVA, followed by the Games-Howell post-hoc test.
RESULTS
The use of bone substitute material led to significantly greater horizontal dimensions amounting to 3.3Â mm (SDâ=â0.67; test 1) and 3.5Â mm (SDâ=â0.72; test 2) compared to spontaneous healing (1.7Â mm, SDâ=â0.23) at 16Â weeks of healing (pââ0.05). The final ridge profile was more favorable after ridge preservation (pâ<â0.001) as demonstrated by a loss of 28.8% (spontaneous healing) and an increase in both test groups at 16Â weeks (test 1â=â60.5% and test 2â=â31.2%).
CONCLUSIONS
The use of alloplastic materials rendered greater horizontal dimensions and a more favorable maintenance of the ridge profile.
CLINICAL RELEVANCE
Alloplastic bone substitute materials can successfully be used for ridge preservation procedures
Soft tissue contour changes at implant sites with or without soft tissue grafting in the esthetic zone: A retrospective case-control study with a 12-year follow-up
OBJECTIVES: To evaluate the volumetric changes and peri-implant health at implant sites with and without previous soft tissue grafting over a 12-year observation period.
MATERIALS AND METHODS: Eighteen patients received dental implants and simultaneously guided bone regeneration in the esthetic zone (15-25) for dental rehabilitation. Three months following implant placement, 8 patients (test) received an additional subepithelial connective tissue graft, whereas 10 patients (control) did not receive any additional treatment. One week after prothesis delivery and at the 5 and 12âyears follow-up examination, impressions were taken. Obtained casts were processed for profilometric and linear analyses. The mean distance (MD) in the mid-buccal area between the two surfaces was considered the primary outcome. Peri-implant health was assessed based on clinical and radiographic data.
RESULTS: Nine female and 7 male patients were re-assessed after a median follow-up time of 144.5 months (Min: 114.8; Max: 213.0). The median reduction of MD amounted to -0.81âmm (Min: -1.39; Max: 0.52) in the test group and -0.56âmm (Min: -0.93; Max: 0.11) in the control group, (intergroup comparison p =â.607, CI 95%: -0.760/0.530). None of the implants was diagnosed with peri-implantitis. Six tests and two control implants were diagnosed with peri-implant mucositis (p =â.103).
CONCLUSIONS: Despite the limited number of included patients, similar results in terms of volumetric, linear changes, and peri-implant conditions could be detected at implant sites with or without soft tissue grafting over a period of 12âyears
13-year follow-up of a randomized controlled study on zirconia and titanium abutments
OBJECTIVES: To assess survival rates and compare technical, biological, and esthetic outcomes of customized zirconia and titanium abutments at 13âyears post loading.
MATERIALS AND METHODS: Initially, 22 patients with 40 implants in posterior regions were included. The sites were randomly assigned to 20 customized zirconia abutments with cemented all ceramic crowns (ACC) and 20 customized titanium abutments with cemented metal ceramic crowns (MCC). At a mean follow-up of 13.4âyears, patients were examined and implants/restorations assessed for survival and technical complications, as well as biological and esthetic outcomes (pocket probing depth [PPD], bleeding on probing [BOP], plaque control record [PCR], bone level [BL], papilla index [PAP], mucosal thickness, and recession (distance of the margo mucosae [MM]/margo gingivae MG)). Descriptive analyses were performed for all outcome measures.
RESULTS: Fifteen patients with 21 abutments (13 zirconia, 8 titanium) were examined at 13âyears. The drop-out rate was 25% (patient level). The technical survival rate of the abutments was 100%. The survival rate on the restorative level (crowns) was 100%. The assessed biological outcomes (PPD, PCR, BOP, BL) and esthetic outcomes (MG, PAP) were similar.
CONCLUSIONS: Zirconia and titanium abutments supporting single implant-borne restorations rendered a high survival rate and minimal differences in terms of technical, biological, and esthetic outcomes at 13âyears of follow-up
Tissue integration and biodegradation of soft tissue substitutes with and without compression: an experimental study in the rat
OBJECTIVES
To analyze the influence of compression on tissue integration and degradation of soft tissue substitutes.
MATERIAL AND METHODS
Six subcutaneous pouches in twenty-eight rats were prepared and boxes made of AlO were implanted and used as carriers for soft tissue substitutes: a collagen matrix (MG), two volume-stable collagen matrices (FG/MGA), and a polycaprolactone scaffold(E). The volume-stable materials (FG/MGA/E) were further implanted with a twofold (2) and a fourfold (4) compression, created by the stacking of additional layers of the substitute materials. The samples were retrieved at 1, 2, and 12Â weeks (10 groups, 3 time points, nâ=â5 per time point and group, overall, 150 samples). The area fraction of infiltrated fibroblasts and inflammatory cells was evaluated histologically. Due to within-subject comparisons, mixed models were conducted for the primary outcome. The level of significance was set at 5%.
RESULTS
The area fraction of fibroblasts increased in all groups over time. At 12 weeks, the densely compressed materials FG4 (1.1%), MGA4 (1.7%), and MGA2 (2.5%) obtained lower values as compared to the other groups, ranging between 4.7 (E2) and 6.5% (MG). Statistically significant differences (pââ€â0.05) were observed between groups FG4 vs MG/FG2/E/E4 as well as between MGA4 vs MG/FG2/E/E4 and E vs MGA2.
CONCLUSIONS
Higher levels of compression led to delayed tissue integration. The effect of different compression levels was more distinct when compared to the differences between the materials.
CLINICAL RELEVANCE
All biomaterials demonstrated tissue integration and a minimal concomitant inflammatory reaction. Clinically, it might be more favorable to obtain a sufficient flap release or to reduce the material size to improve the tissue integration processes
Early implant placement in sites with ridge preservation or spontaneous healing: histologic, profilometric, and CBCT analyses of an exploratory RCT
PURPOSE: The aim of this study was to compare changes in soft and hard tissue and the histologic composition following early implant placement in sites with alveolar ridge preservation or spontaneous healing (SH), as well as implant performance up to 1 year after crown insertion.
METHODS: Thirty-five patients with either intact buccal bone plates or dehiscence of up to 50% following single-tooth extraction of incisors, canines, or premolars were included in the study. They were randomly assigned to undergo one of three procedures: deproteinized bovine bone mineral with 10% collagen (DBBM-C) covered by a collagen matrix (DBBM-C/CM), DBBM-C alone, or SH. At 8 weeks, implant placement was carried out, and cone-beam computed tomography scans and impressions were obtained for profilometric analysis. Patients were followed up after the final crown insertion and again at 1 year post-procedure.
RESULTS: Within the first 8 weeks following tooth extraction, the median height of the buccal soft tissue contour changed by -2.11 mm for the DBBM-C/CM group, -1.62 mm for the DBBM-C group, and -1.93 mm for the SH group. The corresponding height of the buccal mineralized tissue changed by -0.27 mm for the DBBM-C/CM group, -2.73 mm for the DBBM-C group, and -1.48mm for the SH group. The median contour changes between crown insertion and 1 year were -0.19 mm in the DBBM-C/CM group, -0.09 mm in the DBBM-C group, and -0.29 mm in the SH group.
CONCLUSIONS: Major vertical and horizontal ridge contour changes occurred, irrespective of the treatment modality, up to 8 weeks following tooth extraction. The DBBM-C/CM preserved more mineralized tissue throughout this period, despite a substantial reduction in the overall contour. All 3 protocols led to stable tissues for up to 1 year
Heterogeneous Graph-based Trajectory Prediction using Local Map Context and Social Interactions
Precisely predicting the future trajectories of surrounding traffic
participants is a crucial but challenging problem in autonomous driving, due to
complex interactions between traffic agents, map context and traffic rules.
Vector-based approaches have recently shown to achieve among the best
performances on trajectory prediction benchmarks. These methods model simple
interactions between traffic agents but don't distinguish between relation-type
and attributes like their distance along the road. Furthermore, they represent
lanes only by sequences of vectors representing center lines and ignore context
information like lane dividers and other road elements. We present a novel
approach for vector-based trajectory prediction that addresses these
shortcomings by leveraging three crucial sources of information: First, we
model interactions between traffic agents by a semantic scene graph, that
accounts for the nature and important features of their relation. Second, we
extract agent-centric image-based map features to model the local map context.
Finally, we generate anchor paths to enforce the policy in multi-modal
prediction to permitted trajectories only. Each of these three enhancements
shows advantages over the baseline model HoliGraph.Comment: Accepted on IEEE ITSC 202
Clinical and histological comparison of the soft tissue morphology between zirconia and titanium dental implants under healthy and experimental mucositis conditions â A randomized controlled clinical trial
Antipsychotic drugs and their effects on cognitive function: protocol for a systematic review, pairwise, and network meta-analysis.
BACKGROUND
There is evidence that antipsychotic drugs differ in their effect on the cognitive symptoms of schizophrenia. So far, there is no comprehensive systematic review available that would enable providers and patients to make informed choices regarding this important aspect of treatment. With a large number of substances available, conventional pairwise meta-analyses will not be sufficient to inform this choice. To fill this gap, we will conduct a network meta-analysis (NMA), integrating direct and indirect comparisons from randomized controlled trials (RCTs) to rank antipsychotics according to their effect on cognitive functioning.
METHODS
In our NMA, we will include RCTs in patients with schizophrenia or schizophrenia-like psychoses comparing one antipsychotic agent with another antipsychotic agent or placebo that measures cognitive function. We will include studies on patients of every age group, in any phase of illness (e.g., acute or stable, first episode or chronic schizophrenia, in- or outpatients) with an intervention time of at least 3Â weeks. The primary outcome will be the composite score of cognitive functioning, preferentially measured with the test battery developed by the Measurement and Treatment Research to Improve Cognition in Schizophrenia (MATRICS) initiative. The secondary outcomes include the seven cognitive domains that the composite score is composed of, as well as functioning and quality of life. Study selection and data extraction will be conducted by at least two independent reviewers. We will use the Cochrane Risk of Bias tool 2 to determine the risk of bias in studies, and we will evaluate the confidence in the results using Confidence in Network Meta-Analysis (CINeMA). We will perform NMA using R (package netmeta). We will conduct subgroup and sensitivity analyses to explore the heterogeneity and assess the robustness of our findings.
DISCUSSION
This systematic review and network meta-analysis aims to inform evidence-based antipsychotic treatment choice for cognitive deficits in schizophrenia patients by analyzing existing RCTs on this subject. The results have the potential to support patients' and physicians' decision-making processes based on the latest available evidence.
SYSTEMATIC REVIEW REGISTRATION
PROSPERO CRD42022312483
Volumetric and linear changes at dental implants following grafting with volume-stable three-dimensional collagen matrices or autogenous connective tissue grafts: 6-month data
Consensus Report of Working Group 2:Soft Tissue Management
OBJECTIVES: The task of working Group 2 at the 6th Consensus Meeting of the European Association for Osseointegration was to comprehensively assess the effects of soft tissue augmentation procedures at dental implant sites on clinical, radiographic and patientâreported outcome measures (PROMs) including an overview on available outcome measures and methods of assessment. MATERIALS AND METHODS: Three systematic reviews and one critical review were performed in advance on (i) the effects of soft tissue augmentation procedures on clinical, radiographic and aesthetic outcomes, (ii) reliability and validity of outcome measures and methods of assessment and (iii) PROMs applied in clinical studies for soft tissue augmentation procedures at dental implant sites. Major findings, consensus statements, clinical recommendations and implications for future research were discussed in the group and approved during the plenary sessions. RESULTS: The four reviews predominantly revealed: Soft tissue augmentation procedures in conjunction with immediate and delayed implant placement result in superior aesthetic outcomes compared to no soft tissue augmentation in the zone of aesthetic priority. Soft tissue augmentation procedures have a limited effect on marginal bone level changes compared to implant sites without soft tissue augmentation. Clinically relevant parameters (gingival index, mucosal recession) and plaque control improve at implant sites when the width of keratinised mucosa is increased. A variety of aesthetic indices have been described with good reliability. Pink Esthetic Score and Complex Esthetic Index are the most validated aesthetic indices for single implants, though. Superimposed digital surface scans are most accurate to assess profilometric tissue changes. PROMs following soft tissue augmentation procedures have been assessed using various forms of questionnaires. Soft tissue augmentation had a limited effect on PROMs. CONCLUSIONS: Soft tissue augmentation procedures are widely applied in conjunction with implant therapy. Depending on the indication of these interventions, clinical, radiographic and aesthetic outcomes may improve, whereas the effect on PROMs is limited
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