Single implants in the anterior maxilla in young adults

Background: Single anterior implants are frequently used in the treatment of patients with single anterior tooth loss. Compared with other types of implant treatments, single implants are commonly performed in younger patients where the cause of tooth loss often is non-inflammatory. However, there is a scarcity of long-term follow-up studies, especially in the cohort representing the younger segment of the adult population. Lack of periodontal mechanoreceptors (PMRs) around implants and reduced function of PMRs around teeth connected in full-arch bridges have been shown to affect the oral fine motor control. However, there is no study on the comparison of oral fine motor control between single anterior implants and the alternative treatment, a 3-unit bridge. Aims: The objective of this thesis was to investigate the performance of single anterior maxillary single implants in young adults. The specific aims of Studies I and II was primarily to report long-term survival, success, complications, radiological findings and movement of adjacent teeth after 14–20 years follow-up. The secondary aims were to explore correlations between changes in marginal bone levels in relation to probing depth (PD), occlusal contact, and nicotine use, and to investigate the associations between the movement of adjacent teeth, patient and implant characteristics, and the aesthetic assessment of the implant crown. Study III aimed to compare oral fine motor control of patients with single anterior tooth loss treated with 3-unit resin-bonded bridges (RBBs) or single implants. Materials and methods: In Studies I and II, 40 out of 42 patients who received single anterior implants were re-examined after a period of 14–20 years. Data were collected to assess the long-term survival, success, biological findings and complications of the implants. After 14-20 years, radiological findings were compared with baseline data. A 3- D analysis and calculations were used to investigate the movements of teeth adjacent to the single implants and their associations with patient and implant characteristics. Additionally, an assessment of perceived aesthetics was performed. In Study III, a behavioral hold-and-split test was conducted on 16 patients with missing maxillary central incisors. The test was performed twice, once with a 3-unit resin-bonded bridge (RBB) and once with a single implant. The conditions connected tooth (CT), pontic (P), freestanding tooth (T) and single implant (SI) were tested for differences regarding the variables hold force, variability of hold force, split force and duration of split. Results: In Study I, the cumulative survival rate for implants (CSRi) was 96.1% whereas that for crowns was of 80.4% (CSRc). All the remaining implants were considered successful. The mean marginal bone loss was 0.1 ± 1.1 (range, -5.1–1.6) mm and the mean PD was 4.0 ± 1.8 (range, 0–9) mm after 14–20 years follow-up. There was no significant correlation found between marginal bone levels and PD, implant occlusion, or nicotine use (p >0.05). Technical and/or biological complications were found in 50% of the patients, but only 22% required substantial further treatment. In Study II, the 3-D movements of teeth adjacent to the single implant showed a mean movement of 1.0 ± 0.5 mm in the incisal direction (vertical; Y-axis), 0.5 ± 0.8 mm in the bucco-lingual direction (sagittal; Z-axis) and −0.0 ± 0.1 mm in the mesio-distal direction (horizontal; X-axis). No patient showed a completely stable vertical relationship (Y-axis). Lower anterior facial height (LAFH) ≥70 mm was significant correlated with more severe vertical tooth movement (>1 mm) (p <0.05). Furthermore, implants in occlusion, implants in central incisor position and in patients when trauma was the reason for tooth loss were significantly correlated with less movement of teeth adjacent the single implants (p <0.05). Despite the infraposition the patients rated the esthetic of the implant crown to a VAS score of 85% ± 19% (range, 20%– 100%). Significantly lower VAS scores (p <0.05) were correlated with increased tooth movement in patients with central incisor implants. The dentist ratings of 67% ± 23% (range, 10%–100%) were significantly lower that the patients (p <0.05). In Study III, significantly higher (p <0.05) hold force, variability of hold force and split force was found for the single implants compared to the adjacent teeth. Further, the pontic of the RBB showed higher hold forces (p <0.05) than the adjacent connected tooth in a similar manner as the implant. However, no significant differences (p >0.05) were found between the tooth connected in the RBB and the freestanding tooth. Conclusion: Within the limitations of the studies this thesis highlights that single anterior maxillary implants in young adults show good long-term performance with high success and survival rates and only small changes in marginal bone levels. Complications occur over time; however, they do not seem to be of great concern to the patients. Positional changes of adjacent teeth in relation to the single implants occur over time in all patients but to different degrees. However, the changes seem to be more extensive in patients with LAFH ≥70mm, patients without implant occlusion, patients with implants in the lateral and canine positions, and patients with tooth loss caused by reasons other than trauma. Only few patients (10%) found the differences in tooth position esthetically disturbing while the dentist was more critical. Furthermore, single implants show impaired oral fine motor control in relation to freestanding adjacent teeth which was also observed for pontics in relation to connected teeth. However, teeth connected in 3-unit anterior bridges appear to maintain sensitivity in oral fine motor control. Clinical implications: This thesis suggests that patients planned for single anterior maxillary implants should be provided with information that the implant is expected to perform well overtime. However, the implant crown will most likely end up in infraposition in relation to the adjacent tooth. In most patients this will not cause an esthetic problem but in young adults with a long remaining lifetime, the need to change or repair the implant crown may occur once or a few times. To minimize the risk of infraposition, it is advisable to delay anterior maxillary single implant treatment for as long as possible. Patients with a lower anterior facial height of more than 70 mm or implants in lateral or canine position might be in higher risk of more severe infrapositio

Alchemy and the New Age of Cardiac Muscle Cell Biology

Several studies have claimed to identify cardiac stem cells. But what criteria do such cells have to fulfil before we can be confident about their true potential

miR669a and miR669q prevent skeletal muscle differentiation in postnatal cardiac progenitors

miR669a and miR669q inhibit postnatal cardiac progenitor differentiation by directly targeting the 3′UTR of MyoD

Cardiomyocyte Formation by Skeletal Muscle-Derived Multi-Myogenic Stem Cells after Transplantation into Infarcted Myocardium

BACKGROUND: Cellular cardiomyoplasty for myocardial infarction has been developed using various cell types. However, complete differentiation and/or trans-differentiation into cardiomyocytes have never occurred in these transplant studies, whereas functional contributions were reported. METHODS AND RESULTS: Skeletal muscle interstitium-derived CD34(+)/CD45(-) (Sk-34) cells were purified from green fluorescent protein transgenic mice by flowcytometory. Cardiac differentiation of Sk-34 cells was examined by in vitro clonal culture and co-culture with embryonic cardiomyocytes, and in vivo transplantation into a nude rat myocardial infarction (MI) model (left ventricle). Lower relative expression of cardiomyogenic transcription factors, such as GATA-4, Nkx2-5, Isl-1, Mef2 and Hand2, was seen in clonal cell culture. However, vigorous expression of these factors was seen on co-culture with embryonic cardiomyocytes, together with formation of gap-junctions and synchronous contraction following sphere-like colony formation. At 4 weeks after transplantation of freshly isolated Sk-34 cells, donor cells exhibited typical cardiomyocyte structure with formation of gap-junctions, as well as intercalated discs and desmosomes, between donor and recipient and/or donor and donor cells. Fluorescence in situ hybridization (FISH) analysis detecting the rat and mouse genomic DNA and immunoelectron microscopy using anti-GFP revealed donor-derived cells. Transplanted Sk-34 cells were incorporated into infarcted portions of recipient muscles and contributed to cardiac reconstitution. Significant improvement in left ventricular function, as evaluated by transthoracic echocardiography and micro-tip conductance catheter, was also observed. CONCLUSIONS AND SIGNIFICANCE: Skeletal muscle-derived multipotent Sk-34 cells that can give rise to skeletal and smooth muscle cells as reported previously, also give rise to cardiac muscle cells as multi-myogenic stem cells, and thus are a potential source for practical cellular cardiomyoplasty

Species Sensitivity to Hydrologic Whiplash in the Tree-Ring Record of the High Sierra Nevada

Year-to-year variability of precipitation and temperature has significant consequences for water management decision-making. “Whiplash” is a term which describes this variability at its most severe, referring to events at various timescales in which the hydroclimate switches between extremes. Tree-rings in the Truckee-Carson River Basin (California/Nevada watersheds with headwaters in the Sierra Nevada) and similar basins in semi-arid environments can provide proxy records of hydroclimate as their annual growth is tied directly to limitations in water-year rainfall and temperature, but traditional metrics of reporting explained variance do not distinguish a reconstruction’s sensitivity to whiplash events. In this study, a pool of total ring width indices from five conifer species (Abies magnifica, Juniperus occidentalis, Pinus ponderosa, Pinus jeffreyi, Tsuga mertensiana) in the Sierra Nevada were used to develop a series of standardized reconstructions of water-year regional precipitation using stepwise linear regression on lagged chronologies. A nonparametric analysis approach was then used to classify positive and negative whiplash events in observed and reconstructed regional precipitation. The statistical significance of matching events in regional precipitation by tree-ring reconstructions was assessed using a hypergeometric test. Results suggest that reconstructions from individual species and single sites of those species are often able to track whiplash events. Negative events (wet to dry) are generally tracked more consistently than positive events (dry to wet), although tracking sensitivity differs among species and especially strong tracking of positive events is exhibited by Tsuga. Tracking ability does not exhibit a linear relationship with the explained variance of a reconstruction and has little apparent relationship to the magnitude of whiplash events or the monthly distribution of annual precipitation during those whiplash years

Teacher's Experience RegardingControversial Issues in Education

In a world characterized by constant changes and increasing diversity, controversialevents unfold in society on a daily basis. Given the School's role in educating democraticcitizens, it is imperative for educational institutions to adapt and incorporate current andcontroversial topics into their curriculum. This thesis explores the perspectives of socialstudies teachers on controversial issues in the classroom. Employing a phenomenologicalapproach and conducting in-depth interviews with social studies teachers, the studyanalyzes their subjective experiences, definitions of the subject, and approaches toteaching controversial topics. Therefore, our purpose and research questions are groundedin three themes, which are also pervasive throughout the work: Teacher management,teacher experience, and teacher definition of controversial issues in education.In summary, the results from our interview study reveal that teachers acknowledge theemotional impact associated with these issues, a finding supported by prior research. Thechallenge lies in the complexity of these topics and the ability to strike a balance betweenintellectual challenge and emotional understanding. The study highlights the difficultyteachers face in maintaining objectivity while navigating through their own values, andthe intricate interplay between subject content, emotions, and the teacher's ownperspective. It is evident that a conscious effort is required to create a classroomatmosphere that fosters open dialogues and respectful confrontations to promotedemocratic values, where diverse perspectives can be included

Species Sensitivity to Hydrologic Whiplash in The Tree-Ring Record of the High Sierra Nevada

The year-to-year variability of precipitation has significant consequences for water management and forest health. &ldquo;Whiplash&rdquo; describes an extreme mode of this variability in which hydroclimate switches abruptly between wet and dry conditions. In this study, a pool of total-ring-width indices from five conifer species (Abies magnifica, Juniperus grandis, Pinus ponderosa, Pinus jeffreyi, and Tsuga mertensiana) in the Sierra Nevada is used to develop reconstructions of water-year precipitation using stepwise linear regression on lagged chronologies, and the reconstructions are analyzed for their ability to track whiplash events. A nonparametric approach is introduced to statistically classify positive and negative events, and the success of matching observed events with the reconstructions is evaluated using a hypergeometric test. Results suggest that reconstructions can effectively track whiplash events, but that tracking ability differs among species and sites. Although negative (dry-to-wet) events (1921&ndash;1989) are generally tracked more consistently than positive events, Tsuga stands out for strong tracking of positive events. Tracking ability shows no clear relationship to variance explained by reconstructions, suggesting that efforts to extend whiplash records with tree-ring data should consider optimizing reconstruction models for the whiplash signal

Vascular Flora of Adobe Valley and Surrounding Hills, Mono County, California

Adobe Valley and the Adobe Hills lie east of the Sierra Nevada in Mono County, California, and are within the Great Basin Floristic Province. The flora of Adobe Valley and the surrounding hills is influenced by the Great Basin Desert to the east, the Sierra Nevada to the west and the northern Mojave Desert to the south. Adobe Valley is surrounded by the Adobe Hills, Benton Range and Glass Mountain region, creating a circular closed basin with many small tributaries feeding into it. This topography contributes to the creation of a rare wetland complex, including alkali meadows, marshes, and lakes at the base of the hills, which represent some of the more botanically interesting terrain in the region. Prior to this study, the wetland complex of Adobe Valley had not been systematically investigated with regard to its botanical diversity. The vegetation types associated with the wetland complex are listed as threatened by the California Natural Diversity Database and face a number of conservation concerns including water pumping, overgrazing, and possible wind energy development. A total of 1525 herbarium specimens were collected within the study area over 59 days in the field from 2016 to 2018. The vascular flora of the Adobe Valley and Hills includes 397 minimum-rank vascular plant taxa, representing 194 genera and 61 families. Six taxa are only known from historical collections, 21 taxa are non-native and 27 taxa have conservation status. The results of the inventory are presented here in an annotated checklist, along with descriptions of vegetation alliances