Drug induced gingival hyperplasia

Thesis (M.Sc.D.)--Boston University, Henry M. Goldman School of Dental Medicine, 1998 (Periodontology and Oral Biology).Includes bibliographical references: (leaves 31-35).Drug induced gingival hyperplasia is a side effect of certain drugs taken systemically which have an effect intraorally and can affect function and esthetics. In this study we tried to find an explanation at the molecular level. We know from previous experiments that lysyl oxidase is responsible for the cross-linking of collagen. Basic fibroblast growth factor down regulates mRNA levels of lysyl oxidase. The goal of this study was to determine whether drugs (cyclosporin A, dilantin, and nifedipine) block this down regulation allowing increased deposition of ground substance in the extracellular matrix leading to fibrosis. Gingival fibroblasts were treated with nifedipine plus or minus basic fibroblast growth factor. RNA was isolated and changes in lysyl oxidase, collagen, and elastin mRNA levels were measured. The lysyl oxidase enzyme activity was also measured to see if it was concordant with the mRNA levels. Down regulation by basic fibroblast growth factor was reproducible at high concentrations of basic fibroblast growth factor only (1 nM). At 0.1 nM this down regulation was not consistant anymore. The blocking effect produced by the drugs was not reproducible at high or low concentrations of basic growth factor. This may be due to the stage at which the cells were treated, the kind of cells, or the time of treatment

Effect of Systemic Diseases on Periodontal Microbiome. A Literature Review. Part III

Periodontitis is defined as a chronic inflammatory disease and is mainly caused by a dysbiosis of the periodontal microbiome. Many systemic diseases have been linked to periodontal disease, and the alteration of the microbiome plays a major role in the pathogenesis. Diabetes has been highly associated with the increased risk of periodontal disease, as it provides a hyperglycemic microenvironment that heavily influences the periodontal microbiome by reducing its diversity and favoring disease associated bacteria. Rheumatoid arthritis has also been associated with periodontitis, with many studies indicating microbial shifts in affected individuals without reaching a consensus on the precise nature of dysbiosis. Contradictory and limited number of studies focusing on the effect of other diseases (systemic lupus erythematosus, human immunodeficiency virus, leucocyte adhesion deficiency, liver diseases) on the periodontal microbiome have been also conducted, and many of them have shown distinct microbial shifts in affected individuals

Correlation of the Initial Bone Height to the Middle Facial Height and the Maxillary Sinus Volume: A Retrospective Study

This study aims to measure and establish a correlation between the initial bone height (IBH) at the dentate posterior maxillary sextants to the middle facial height (MFH) and the maxillary sinus volume (SV). Thirty CBCTs split evenly between males and females were retrospectively selected and processed to measure the SV and the IBH from the first premolar to the second molar. A clinical measurement was performed on each patient to evaluate the MFH. A significant positive correlation was found between MFH and SV. No significant correlation was found between the IBH of the first premolar and the SV or MFH on both sides. The results showed a significant negative correlation between the IBH of the other teeth examined and the SV on both sides. A significant negative correlation was found between the MFH and the IBH of the second premolar, first molar, and second molar of each side. It can be concluded that the maxillary SV increases with the MFH, and the IBH decreases when the SV and the MFH increase except for the first premolar. The clinical relevance of this study lies in the capability of the general practitioner to estimate the IBH in the posterior dentate maxilla by measuring the MFH. Patients with a risk of having a low IBH can be advised, in the case of an extracted tooth, to consider ridge preservation techniques or implant therapy as soon as possible to avoid future complex surgical interventions

Clinical and radiographic evaluation of bone remodeling around implants placed in horizontally augmented bone: A pilot study

Introduction: Marginal bone loss after implant placement is one of the most used criteria to assess the success of osseointegrated implants over time. The type of implant connection and implant surface type are reported to have an influence on bone remodeling around the placed implants. This study aimed to evaluate marginal bone loss around two implant systems with different connections and surfaces in horizontally augmented sites. Methods: This randomized control pilot study included 8 implants placed in 3 patients who needed implant placement in previously horizontally grafted sites. The placed implants were divided into two groups: group 1 consisting of implants with external connection and a hybrid design, and group 2 including implants with an internal connection and a fully etched surface. Clinical and radiographical measurements were taken at baseline, during the surgery, and up to one year after loading to evaluate marginal bone loss around the two different implants placed in grafted sites. Results: All implants were retained at all follow-up periods and healing was uneventful. There were similar Marginal Bone Loss (MBL) and soft tissue changes around both types of implants. Group 2 implants had higher MBL, however, the difference was not statistically significative. Conclusion: Preliminary analysis suggest that full surface etching does not seem to negatively influence marginal bone loss around implants placed in augmented bone

Periodontal Microbiome Part I: A Literature Review

Periodontal disease is one of the most chronic infectious diseases, it is initiated by a reversible inflammatory condition called gingivitis, if untreated, it progresses to an irreversible condition called periodontitis, if not resolved, it leads to tooth loss. Periodontitis is a multifactorial disease, one of these factors is the periodontal microbiome. Consequently, the microbiome is altered according to the host state i.e., health, gingivitis, periodontitis. The microbiome in health is comprised of a variety of microorganisms called health-associated species. They consist of gram-positive cocci and rod with gram-negative species. In this state, the microbiome participates in various physiological functions. While in gingivitis, the microbiome shifts in its composition and can now initiate an inflammatory condition. While in periodontitis, the microbiome is changed to a state where new microorganisms emerge which initiate a periodontal tissue destruction phenomenon. These microorganisms are referred to disease-associated species. Environmental factors are present in which they alter the microbiome composition. Smoking and diabetes were one of the strong extrinsic factors that negatively shape the microbiome into a more aggressive form. Individuals with poor glycemic control or consume tobacco products are more prone to periodontal diseases because their microbiome is rich in bacterial complexes which negatively affects the periodontium. The effect of antibiotic consumption on the microbiome was more or less advantageous, it was observed that not all antibiotics affect the microbiome composition

Peri-Implant Microbiome: A Literature Review Part II

Dental implants are now considered the treatment option for missing teeth. They hold a high survival rate with great patient satisfaction. In the last 3 decades, new infectious diseases emerged around dental implants, termed peri-implant mucositits and peri-implantitis. These infectious diseases comprise similar characteristics to periodontitis, including soft and hard tissue loss. The etiology of peri-implant disease is many, one of them is the alteration of the peri-implant microbiome. In health, implants comprise mainly of facultative anaerobic gram-positive cocci, in which the microbiome resides in a symbiotic state where all microorganisms co-exist with each other. On the other hand, diseased implants include gram-negative anaerobic rods and spirochetes, in which the microbiome resides in a dysbiotic state, where disease-associated species and the metabolic activity is increased. This microbial shift occurs due to many reasons such as the presence of periodontitis history, adjacent diseased natural teeth, and implants placed in periodontally affected subjects. Candidate individuals with a strict supportive periodontal care along with controlled local and systemic factors, that negatively affect the microbiome, is mandatory to maintain the symbiotic state around dental implants

Radiographic marginal bone level evaluation around two different tissue-level implant systems: a one-year prospective study

BACKGROUND: Marginal bone loss, is a frequently reported variable in the evaluation of dental implants. The primary objective of this study was to evaluate radiographic marginal bone level changes around the two different tissue-level implant systems placed adjacently in the posterior maxilla or mandible. The influence of implant macro-geometry and vertical soft tissue thickness on marginal bone loss were also evaluated.METHODS: Seven patients were included in the study and a total of 18 implants were analyzed. Each patient received two different implants placed adjacently in the maxilla or the mandible. The implants used in our study were either Straumann (R) SP cylindrical implants or JD Octa (R) tapered implants. During the surgery, vertical soft-tissue thickness was measured with a periodontal probe placed on the top of the bony crest and in the center of the future implant site. Healing abutments were then seated. Three months following implant placement, impressions were taken, and screw-retained metal ceramic prostheses were delivered. Standardized intraoral radiographs were taken immediately after implant placement and one year following implant loading in order to assess marginal bone level changes.RESULTS: Results showed a mean marginal bone loss of 0.55 +/- 0.5 mm for Straumann (R) SP implants and 0.39 +/- 0.49 mm for JD Octa (R) implants after one year of loading and the difference was not statistically significant between the two systems. A statistically significant correlation was found between soft tissue thickness and marginal bone loss; in sites with thin mucosal tissues (<= 2 mm), there was significantly greater bone loss compared to sites with thick, soft tissues (> 2 mm) in both implants.CONCLUSIONS: Radiographic marginal bone loss was not statistically different between the two implant systems at the one-year examination period. Moreover, vertical soft tissue thickness influenced marginal bone loss regardless of the implant system used

A randomised, blinded, trial of clopidogrel versus aspirin in patients at risk of ischaemic events (CAPRIE). CAPRIE Steering Committee

Many clinical trials have evaluated the benefit of long-term use of antiplatelet drugs in reducing the risk of clinical thrombotic events. Aspirin and ticlopidine have been shown to be effective, but both have potentially serious adverse effects. Clopidogrel, a new thienopyridine derivative similar to ticlopidine, is an inhibitor of platelet aggregation induced by adenosine diphosphate. METHODS: CAPRIE was a randomised, blinded, international trial designed to assess the relative efficacy of clopidogrel (75 mg once daily) and aspirin (325 mg once daily) in reducing the risk of a composite outcome cluster of ischaemic stroke, myocardial infarction, or vascular death; their relative safety was also assessed. The population studied comprised subgroups of patients with atherosclerotic vascular disease manifested as either recent ischaemic stroke, recent myocardial infarction, or symptomatic peripheral arterial disease. Patients were followed for 1 to 3 years. FINDINGS: 19,185 patients, with more than 6300 in each of the clinical subgroups, were recruited over 3 years, with a mean follow-up of 1.91 years. There were 1960 first events included in the outcome cluster on which an intention-to-treat analysis showed that patients treated with clopidogrel had an annual 5.32% risk of ischaemic stroke, myocardial infarction, or vascular death compared with 5.83% with aspirin. These rates reflect a statistically significant (p = 0.043) relative-risk reduction of 8.7% in favour of clopidogrel (95% Cl 0.3-16.5). Corresponding on-treatment analysis yielded a relative-risk reduction of 9.4%. There were no major differences in terms of safety. Reported adverse experiences in the clopidogrel and aspirin groups judged to be severe included rash (0.26% vs 0.10%), diarrhoea (0.23% vs 0.11%), upper gastrointestinal discomfort (0.97% vs 1.22%), intracranial haemorrhage (0.33% vs 0.47%), and gastrointestinal haemorrhage (0.52% vs 0.72%), respectively. There were ten (0.10%) patients in the clopidogrel group with significant reductions in neutrophils (< 1.2 x 10(9)/L) and 16 (0.17%) in the aspirin group. INTERPRETATION: Long-term administration of clopidogrel to patients with atherosclerotic vascular disease is more effective than aspirin in reducing the combined risk of ischaemic stroke, myocardial infarction, or vascular death. The overall safety profile of clopidogrel is at least as good as that of medium-dose aspirin

Coronal Heating as Determined by the Solar Flare Frequency Distribution Obtained by Aggregating Case Studies

Flare frequency distributions represent a key approach to addressing one of the largest problems in solar and stellar physics: determining the mechanism that counter-intuitively heats coronae to temperatures that are orders of magnitude hotter than the corresponding photospheres. It is widely accepted that the magnetic field is responsible for the heating, but there are two competing mechanisms that could explain it: nanoflares or Alfv\'en waves. To date, neither can be directly observed. Nanoflares are, by definition, extremely small, but their aggregate energy release could represent a substantial heating mechanism, presuming they are sufficiently abundant. One way to test this presumption is via the flare frequency distribution, which describes how often flares of various energies occur. If the slope of the power law fitting the flare frequency distribution is above a critical threshold, $\alpha=2$ as established in prior literature, then there should be a sufficient abundance of nanoflares to explain coronal heating. We performed $>$600 case studies of solar flares, made possible by an unprecedented number of data analysts via three semesters of an undergraduate physics laboratory course. This allowed us to include two crucial, but nontrivial, analysis methods: pre-flare baseline subtraction and computation of the flare energy, which requires determining flare start and stop times. We aggregated the results of these analyses into a statistical study to determine that $\alpha = 1.63 \pm 0.03$. This is below the critical threshold, suggesting that Alfv\'en waves are an important driver of coronal heating.Comment: 1,002 authors, 14 pages, 4 figures, 3 tables, published by The Astrophysical Journal on 2023-05-09, volume 948, page 7