Week 5 Respiratory Disorders PDF

**[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**  **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 **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  - 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 - 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 **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** - 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