Summary

These lecture notes cover various respiratory disorders including asthma, sleep apnea, respiratory tract infections, cystic fibrosis, and tuberculosis. The notes detail symptoms, triggers, and potential treatments for each condition. The document includes diagrams and explanations of different types of asthma and their treatments.

Full Transcript

**[Week 5]** Dr Pierce- L1 Disorders of the respiratory system - **Asthma**- variable obstructive airway disease - Chronic obstructive pulmonary disease- chronic bronchitis and emphysema **Sleep apnea**- characterized by interruptions (apneas) in breathing during sleep - **Re...

**[Week 5]** Dr Pierce- L1 Disorders of the respiratory system - **Asthma**- variable obstructive airway disease - Chronic obstructive pulmonary disease- chronic bronchitis and emphysema **Sleep apnea**- characterized by interruptions (apneas) in breathing during sleep - **Respiratory tract infection** - **Cystic fibrosis**- excessive mucus in respiratory and digestive systems - **Tuberculosis**- mostly infects lungs and can cause death if left untreated **Asthma attacks** - Unpredictable, disabling attacks of severe dyspnea, coughing and wheezing triggered by sudden episodes of bronchospasms - May be virtually asymptomatic between attacks - May prove fatal in a state of unremitting attacks - Significant reduction in forced expiratory volume and peak expiratory flow rate **Asthma- Bronchoconstriction and inflammation** - Bronchoconstriction- triggered by stimulus with little or no effect on individuals with normal airway function - Sometimes by exposure to allergen to which patient has been previously sensitized - Key feature- underlying chronic inflammation of airways - Inflammation-related damage to the airway epithelium- amplifies neural, inflammatory and immune responses in the airways **Allergic (atopic) vs non-allergic (non-atopic) asthma** ![A blue background with white text Description automatically generated](media/image2.png) **Allergen-triggered asthma- Type 1 hypersensitivity reaction** - Occurs in individuals who have previously been sensitized to an antigen A close-up of a sign Description automatically generated ![](media/image4.png)**Typical allergens** - Foods, animal sources, environmental factors, medication and others - Rapid onset of effect stage- happens within minutes after the antigen combines with an antibody bound to mast cells or basophils **Allergen-triggered asthma- effect stage** Early-phase reaction (within 15 minutes)- mast cell degranulation - Dominated by bronchoconstriction and wheezing, increased mucus production, variable degrees of vasodilation, and increased vascular permeability - Mediators produced by mast cells and basophils trigger bronchoconstriction by direct stimulation of subepithelial vagal (parasympathetic) receptors Late phase reaction (4-6 hours after exposure)-cellular inflammation - Dominated by recruitment of leukocytes, notably eosinophils, neutrophils and T-cells - Cellular infiltration, fibrin deposition and tissue destruction resulting from the sustained allergic response cause increased bronchial reactivity, oedema and further inflammatory cell recruitment **Non allergenic asthma- drug induced** Aspirin - Some individuals are incredibly sensitive to aspirin and NSAIDs - Inhibition of the cyclo-oxygenase pathway in arachidonic acid metabolism may favour activity of the lipoxygenase pathways- increased production of the broncho-constricting leukotrienes Codein and morphine - Stimulate mast cells Therapeutic intervention- bronchodilators (relieves) - Relax the airway smooth muscle- bronchodilation - B2 adrenoceptor agonsits, e.g. salbutamol (Ventolin) i. Mimic actions of adrenaline ii. May be used in all patients with asthma iii. Long-term use can decrease saliva production- xerostomia-increased risk of caries - Methylxanthines e.g. theophylline i. Useful bronchodilators but can only be given oral (or IV) ii. Weak anti-inflammatory actions - Bronchodilators may exacerbate gastro-esophageal reflux- can contribute to enamel erosion **Anti-inflammatory drugs (preventers)** - Inhaled corticosteroids- useful anti-inflammatory agents for acute severe asthma (beclomethasone, budesonide etc.) - Reduces inflammatory cell numbers and decreases airway hyper-responsiveness to non-specific stimuli and antigens - Also, direct inhibitory effect on T-cells, eosinophils, etc. - Increase the risk of oral candidiasis-advise patient to rinse mouth after using their "preventer" inhaler **Asthma and the dental clinic** Environment with an increased risk of an asthmatic attack - Dental materials and products may exacerbate asthma- dentifrices, sealants, sealants, acrylics, tooth enamel and aerosols - Medications: aspirin and other NSAIDS, some opioid analgesics (codeine) - Anxiety and stress - Remind patient to bring their bronchodilator and have one available - Can use bronchodilator as a preventative - Assess recent history of episodes - Evaluate current symptoms and reschedule if signs of asthma, such as coughing and wheezing - Provide stress-free environment - Elective dentistry only in asymptomatic or well-controlled asthmatic patients - Analgesic of choice is paracetamol unless you know NSAIDs are safe in that patient **Chronic obstructive pulmonary disease (COPD)\ **- 4^th^ leading cause of death worldwide ![A close-up of a sign Description automatically generated](media/image6.png) - Similar risk factors and causes - Most significant risk factor- cigarette smoking - Long-term exposure to lung irritants- chemical vapours, pollutants, and dust from grain or wood - Genetic- a disorder known as alpha-1 antitrypsin deficiency can trigger emphysema, even if no other risk factors are present **Chronic bronchitis** - Persistent cough with sputum for at least 3 months in at least 2 consecutive years in the absence of any other identifiable cause - Fundamental structural change- alteration in the mucosal lining of the bronchi - Caused by tabacco smoking and other inhaled pollutants - Mucus hypersecretion due to enlarged submucosal glands and marked increase in goblet cells i. Airways narrow by thickness of mucosa and excessive mucous production - Inflammatory infiltration and fibrosis of the bronchial walls- chronic aiway obstruction **Progression of chronic bronchitis** - Often presents indsidiously with slowly increasing dypnea on exertion and chronic cough with sputum production - Clinical picture varies according to the severity of the bronchitic changes - Can lead to pulmonary hypertension (cor pulmonale) and death due to heart failure **Emphysema** - Irreversible enlargement of airspaces distal to terminal bronchioles with destruction of their walls - Reduced elastic recoil pressure-reduced pressure for expiratory flow - Four major types on segments of the respiratory units involved: centriacinar, panacinar, paraseptal, and irregular (only first two cause clinically significant airflow obstruction) **Centriacinar emphysema** - Most common form - Predominantly - Centrally or proximal parts of acini affected, with distal alveoli spared - Both emphysematous and normal airspaces within the same acinus - More common and more pronounced in upper lobes **Panacinar emphysema** - Associated with a1-antitrypson deficiency and exacerbated by smoking - Acini uniformly enlarged from respiratory bronchiole to terminal alveoli - More common in lower zones and anterior margins of the lung and usually most severe at the bases **Pathogenesis of emphysema** - Biochemical cellular, and molecular mechanisms underlying COPD pathobiology are not yet well understood - ![](media/image8.png)Clinically significant emphysema largely confined to smokers and to patients with a1-antitrypsin deficiency **Emphysema, bronchitis or both** Pure chronic bronchitis - Cardinal symptom is persistent cough with abundant sputum - History of recurrent respiratory infections - Hypercapnia and severe hypoxemia - May have signs of right heat failure (cor pulmonae), such as oedema and cyanosis (lips and fingertips) Severe - Barrel-chested and dyspneic with obvious prolonged expiration - Sits forward in a hunched-over position - Breathes through pursed lips - Mostly slight cough - Severe overdistention of lungs **COPD is linked to oral health and periodontitis** - Association between poor oral health and periodontal disease and progression of COPD - Possibly linked to immune cell activation mediated by pathofenic bacterial species in dental plaque also foind in acute exacerbation of chronic bronchitis - Periodontal therapy in COPD patients may improve ling function and decrease frequency of COPD exacerbations Sleep apnoea - Sleep disorder characterised by interruptions in breathing during sleep that can last for several seconds to minutes - Obstructive SA 1. Most prevelant form-occurs when tongue and throat muscles relax excessively during sleep, causing airway to narow or close-loud snoring or choking sounds 2. Often associated with obesity and more common in men - Central SA 1. Brain respiratory centres not responding properly to rising CO~2~ levels- no regular contraction of diaphragm and intercostal muscles 2. Often related to medical conditions such as heart failure and pharmacologic agents 3. More common in older adults - Complex SA syndrome 1. Combination of OSA and CSA 2. Occurs when someone with OSA develops CSA after starting continuous positive airway pressure (CPAP) therapy for their OSA **Sleep apnoea symptoms** - Loud snoring - Choking or gasping for air during sleep - Excessive daytime sleepiness - Morning headaches - Difficulty concentrating - Irritability Treatment of sleep apnoea Depends on type and severity of the condition - Lifestyle changes- for mild cases of OSA: e.g. weight loss, avoding alcohol and sedatives and side sleeping - CPAP (Continuous Positive Airway Pressure): most common treatment for moderate to severe OSA-delivers a steady flow of air pressure to keep the airway open during sleep - BiPAP (Bilevel Positive Aiway Pressure): similar to CPAP but offers different pressures for inhaling and exhaling-more comfortable for some individuals - Oral appliances (mandibular advancement devices): prescribed by dentists to reposition lower jaw to help keep the airway open - Medications- addressing the underlying medical condition **Sleep apnoea** - Can affect the structures of the mouth and throat-xerostomia - Periodontal disease suggested to be associated with OSA - Use of oral appliances may cause dental issues such as changes in bite or discomfort - Regular dental check-ups essential - Provide guidance on oral hygiene and help manage any issues that may arise from sleep apnoea treatment Cystic fibrosis - Monogenic disorder inherited in an autosomal recessive manner - Caused by mutations in the CTFR gene, which is responsible for the formation of a chloride channel in the epithelial cells membranes - Defective CTFR protein leads to thick, sticky mucous production, affecting various organs, especially the lungs and digestive system **Symptoms** Respiratory symptoms - Persistant cough with thick mucous - Wheezing or difficulty breathing - Excerise intolerance - Repeated lung infections - Inflamed nasal passages or stuffy nose - Recurrent sinusitis and pneumonia Other symptoms - Salty sweet-produce muscle cramps or weakness - Tiredness, lethary or reduced ability to exercise - Poor growth or weight gain - Frequent visits to the toilet - Poor apetite - CF-related diabetes - Infertility in males **Cystic fibrosis management** - Medication: antibiotics, antinflammatory drugs, mucus thinners, and bronchodilators - Nutrition: high-protein, zinc containing and calcium rich foods - Therapies: breathing exercises, chest physical therapy, enzyme replacement and oxygen therapy - Procedures: Bronchoscopy, bowel surgery, and lung transplantation - Specialists: pulmonologists and gastoenterologists **Oral health impact of cystic fibrosis** - Dry mouth due to reduced saliva production or as eefect of pharmacotherapy - Increased risk of dental caries and periodontal disease - Enamel defects possibly resulting from the genetic disease background - Difficulty maintaining oral hygiene - Regular dental check-ups are crucial for CF patients **Dental considerations** - Appointment allocation to minimise patient-to-patient contact - Limiting trement provision to a single allocated surgery - Ensuring that all staff members do not have any transmissible illness - Enforcing meticulous cross-infection control and dental chair water-line disinfection - Shorter appointment times and regular breaks during treatment - Providing treatment with patient in an upright or semi-upright position in the chair to facilitate clearance of airway secretions **Tuberculosis aetiology and symptoms** - Caused by the bacterium mycobacterium tuberculosis - Transmission occurs through inhalation of airborne droplets containing the bacterium or direct contact - Primarily affects the lungs but can also involve other organs - Common symptoms include persistant cough (often with blood), fatigue, weight loss and night sweats - Oral manifestations are rare but may include ulcerations, granulomas and swollen lymph nodes in the neck (oral tuberculosis) Tuberculosis treatment and dental care - Treatment involves a combination of antibiotics (e.g. isoniazid, rifampin) - Patients with active TB are infectious and require specialised medical treatment - Patients with latent tuberculosis are not infectious; can be treated under standard infection control precautions - However, for a person with active TB, standard precautions are insufficient to prevent transmission of the bacterium - Dental health care providers can defer non-emergency treatment until patients are non-contagious after medical treatment **[Dr Touraj L1]** Enamel - Minerals 95% by weight - Protein 4% by weight - Water 1% by weight - Translucent, brittle, hardest material in body 300-500 KHN, permeable Dentine - Mineral 70% by weight - Water 10% by weight - Organic matrix 20% by weight - More suspectable to demineralisation - More opaque and resilient than enamel, harness value is 50-70KHN **Light and colour** - One of the most demanding requirement of dental materials is their colour match with natural tissues - Based on the munsell scale colour can be analysed by three independent parameters in 3 Dimensions 1. Wavelength 2. Intensity 3. Brightness Colour - Hue and Chroma are inherent properties of the materials and created by manufacturers, but brightness can be altered by surface polishing - Change in hue and chroma can occur intrinsically by degredation or transformation in the molecules or extrinsically by adsorption of stains - As chroma increaes, the value decreases; they are inversly related - The chroma of a natural tooth comes mainly from the dentin, and the thickness and opacity of the underlying enamel determine how much chromatic influence the dentin has - Value is the total amount of light returned from an illuminated object and is influenced by enamel thickness and quality - Fluorescence is the property of a material to absorb light of a particular wavelength and then to emit light of a different wavelength and therefore, colour. Teeth fluoresce bluish-white when exposed to ultraviolet radiation - Dentin has much greater fluorescent properties than enamel due to organic particles - Metamerism can have an effect on the appearance of a tooth or restoration. Metamers are objects which match each other under one set of light conditions but mismatch under another as the light has different spectral properties What is a composite resin - Organic resin materis 1. Monomer- Bis-GMA or UDMA 2. Viscosity controllers- MMA, EGDMA, TEGDMA 3. Inhibitor- hydroquinone 4. Activator and initiator- i. chemical cure (aromatic tertiary amine +BPO) ii. Light cure e.g. camphorquinone + aliphatic amine 5. Modifying resin matrix i. Reduced polymerisation shrinkage- MMA 22 vol% Bis-GMA 7 vol% - Inorganic filler 1. Reduce polymerisation shrinkage 2. Reduce coefficient of thermal expansion i. Methacrylate monomers- 80ppm/degrees C ii. Enamel- 11ppm/degrees C iii. Glasses- 8 ppm/degrees C 3. Improve mechanical properties 4. Provide radiopacity 5. Control aesthetics - Coupling agent 1. Role is to act as a strong and durable link between two materials which have no natural affinity for each other Resin Filler interface- compressive strength and fatigue limit are reduced by 30% when coupling agent is not used ![](media/image10.png)**Silane Coupling agent** **Resin matrix technology- Chemical cure system two paste composites** - Catalyst- tertiary amine - Base- benzoyl peroxide - Porosity- limited mixing and working time increases risk of porosity i. Reduces compressive strength and fatigue limit **Factors affecting mechanical properties of resin composites** - Porosity - Filler content - Type of filler - Efficiency of filler-resin coupling **Limited depth of Cure** - Intensity of the light decreases exponentially by increaing the distance - The depth of curing reduces by increasing the darkenss and opacity of materials - Increasing the exposure time to more than that recommended does not increase the curing deptj significantly - The depth of the curing can be significantly reduced by reducing light exposure time of less than that recommended **Visible light curing system** - Command set - No mixing - Improved colour stability Light curing units - Halogen light (quartz tungsten halogen) - Blue-LED (460-480nm): energy efficient, less heat emitting, portable, rechargeable, easy cross infection controlled, long service life but narrow spectrum - Argon laser (high intensity): greater depth and degree of cure in a shorter time, but may compromise integrity of tooth-composite interface and is very expensive, but narrow spectrum - Plasma Arc Light: intesity and compromised marginal integrity=argon laser, but low cost - The performance of dental curing light units should be checked regularly either by light intensity meter or curing depth on composites **Conventional VLC resin composite** - Incremental packing of non more than 2mm depth at a time - Cure each layer for \>40 seconds - Bonding via the oxygen inhibited surface layer - High blue light intensity light source (470-480nm) - Place the light tip as close as possible - Ensure that the light tip is not contaminated - Use transparent matrices and wedges when possible - Apply curing light on the bonding side not the free surface as much as possible - Glycerine (oxygen barrier) **Recommendations** - Composite ideally should be used when all the marigns are in enamel - Incremental placement and through-the-tooth curing can eliminate gap formation under light cure resin **Incremental packing** - Minimise effects of polymerisation shrinkage - Reduce stress at the interface - Ensure complete cure of each increment - The initial curing at the base through the tooth then from occlusal surface Fillers Compsition 1. Quartz (hardest particle) 2. Fused silica 3. Silica-based glass particle - Better aesthetic and polishabiltiy but increased water sorption, a higher coefficient of thermal expansion, decreased elastic modulus, lower fracture resistance, stiffness and fatigue strength - The surface area has a direct relationship\[ with the number of the particles - Large surface area and less loading possiblity, but minimum shrinkage **Hybrid Composite resins** - Glass particles- 5-20 micrometers - Colloidal silica- 0.01-0.05 micrometers - (60-70% Vol %) **Small particle-Hybrid composite** - Glass particle site- 0.1-6 micrometers + colloidal silica (small particles) **Filler technology** - Nanocomposites 1. Silica nanoparticles (2-20nm) 2. Zirconia- silica nonclusters (0.6 micrometers) 3. 78% vol % **The role of filler particles** - ![](media/image12.png)Reduce polymerisation shrinkage 1. Modifying resin matrix i. MMA 22 vol % ii. Bis-GMA 7 vol % **The filler** - Reduce polymerisation shrinkage - Reduce coefficient of thermal expansion 1. Methacrylate monomers- 80ppm/degrees C 2. Enamel- 11ppm/degrees C 3. Glasses- 8ppm/degrees C - Improve mechanical properties 1. Increase strength or toughness 2. Increase elastic modulus 3. Increase hardness and wear resistance - Provide radiopacity 1. Incorporate heavy metals in the glass i. Barium ii. Strontium iii. Be able to detect caries under the restoration - Control aesthetics **Classification based on application** - Conventional resin composites - Packable composites (trimodal filler size distribution, higher filler content, modified resin) poor aesthetic - Flowable composites: (less filler content, bigger filler size, high resin) poor mechanical properties - Bulk-fill composite can be divided into flowable bulk-fill composite and non-flowable (paste-like) bulk-fill composite. The flowable bulk-fill composite was initially used as an injectable material **Bulk-fill composite** - Modified resin matrix to relive the polymerisation stress - Less and different tpyes of filler particles to provide translucency - Sensitive light initiator - E.g.- SDR flow, Filtek one bulk-fill and tetric-N-ceram and sonicFill 2 - Short fiber reinforced composites- indicated for dentin replacement in direct restoration and for core build-up. Depth of cure of 5.5mm - Generally, flowable composites are to replace the dentine only due to low wear resistance **Water sorption and solubility** - Absorption- water sorption by resin matrix - Adsorption- water sorption onto the particle-resin interface as a result of poor bonding in between **Biocompatibility** - Bisphenol-A- can induce change in oestrogen-sensitive organs - MMA and TEGMA- cytotoxicity and hypersensitvity - Nanoparticles (growing concern) 1. Hardly cleared from respiratory system. The particels can accumulate in the lungs, pass through skin/mucosa enter system circulation and accumulate in different organce through cell membrane

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