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Saliva and Oral Health Part 1

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1 Saliva and Oral Health Part 1
Maintaining Oral Health Preventing Dental Disease A CPD Module for Dental Professionals 1 Hour Verifiable CPD

2 Overview Saliva - Production - Composition - Function Biofilm New Insights - Composition - Activity - Fluoride resistance Chewing Gum and Saliva - Flow rate - Clearance - Buffering Caries - Plaque pH - Demineralisation-Remineralisation Erosion - Prevalence - Causes - Aetiology- Management Clinical Assessment - Examination - Chair side Tests - Recommendations (CRA BEWE)

3 Saliva Major Salivary Glands Minor Salivary Glands Saliva Secretion
- Parotid - Sublingual - Submandibular Minor Salivary Glands Lips, tongue, cheek, palate Saliva Secretion - Parotid Serous saliva - Sublingual Mucous saliva - Submandibular Mixed saliva

4 Saliva Mixed Salivary Acinus Salivary Acini Serous Cells Mucous Cells
Basic secretory units of salivary glands. Serous Cells - Stain darkly. - Wedge shaped with round nucleus. Tight spherical formation. Mucous Cells - Stain lightly. - Tubular shaped with flattened nucleus. - Open formation larger central lumen. Serous Cell Basement membrane Mucous Cell Intercalated duct Salivary duct (secretory) End piece Serous Demilune The basic secretory units of the salivary glands are acini. They are in effect saliva factories. Fluids from the local vasculature are collected by the end pieces. As this flows through the central lumen, serous cells add the serous components and mucous cell provide the thicker mucous component of saliva. This flows through the duct and is secreted into the mouth via the salivary ducts. © Reeves 2013

5 Saliva Serous Acini Mucous Acini Mixed Acini
Histology varies by gland type Serous Acini Mucous Acini Mixed Acini Parotid Sublingual Submandibular

6 Saliva Saliva Formation Stage One: Primary Saliva Local Vasculature
©Reeves 2013 Saliva formed in acini flows down DUCTS to empty into the oral cavity ACINI- water and ions derived from plasma

7 Concentration Gradient
Saliva Saliva Formation Stage Two: Final Saliva Proteins Na+& Cl- K+ ©Reeves 2013 Hypotonic Final Saliva Concentration Gradient Concentration Gradient H2O Water and electrolytes Isotonic Primary Saliva

8 Saliva The Composition of Saliva 99.4 % Water
0.2 % Soluble inorganic substances: sodium, potassium, calcium, chloride, bicarbonate, phosphate, fluoride 0.3% Soluble organic substances: proteins, digestive enzyme (amylase), mucins, antibodies (immunoglobulins), urea, peroxidases, antioxidant enzymes (SOD catalase gluathione) 0.1 % insoluble substances

9 Saliva The Composition of Saliva Composition Unstimulated Stimulated
Water and Electrolytes Water % % Solids 0.45% 0.47% Flow Rate(ml/min) 0.32   0.84 pH   0.17 Sodium (mmol/L)   11.74 Potassium   2.70 Bicarbonate   5.06 Phosphate   0.55 Chloride ±  7.38 Calcium ± ± 0.35 Na+& Cl- K+ Saliva and Oral Health Edgar M, Dawes C, O’Mullane D Eds. 4th Ed 2012

10 Saliva The Composition of Saliva Water and Electrolytes Na+& Cl- K+
Changes in the salivary flow rate and main electrolytes in whole saliva secreted over 20 minutes in 12 subjects while they chewed a piece of sugar-free gum, preceded by a five-minute collection of unstimulated saliva. mmol/L: Millimoles/liter. mL: Milliliters. Na: Sodium. K: Potassium. Ca: Calcium. Cl: Chloride. HCO3: Bicarbonate. Pi: Inorganic phosphate. Source: Dawes and Dong.18 Dawes, C. JADA 2008;139:suppl 2:18S-24S

11 Saliva Water Solids Flow Rate pH Organic Total protein MUC5B MUC7
Amylase Lactoferrin Statherin Albumin Glucose Lactate Urea Unstimulated Stimulated 99.55 % % 0.45% % 0.32 ± ± 0.84 7.04 ± ± 0.17 1630 ± ± 290 830 ± ± 200 440 ± ± 330 317 ± ± 390 8.4 ± ± 4.7 4.93 ± 0.61 51.2 ± ± 53.0 79.4 ± ± 27.1 0.20 ± ± 0.17 3.57 ± ± 0.92 ± 1.64 Saliva Saliva and Oral Health, Edgar M. Dawes C., O’Mullane, D. Eds. 4th Ed, 2012

12 Saliva The Functions of Saliva Resting Saliva Oral Protection System
Secretion Submandibular % Parotid % Sublingual ~ 7-8% Minor glands ~ 7-8% Oral Protection System - Secretion rate: mls/min - Texture: Viscous (mucus) - Rich in mucins - pH value - Functions: Coating of the teeth: salivary pellicle - Lubrication of oral mucosa Stimulated Saliva Parotid % Submandibular % -Sublingual ~ 10% and minor glands Oral Repair System - Secretion rate: 1-3mls/min - Consistency: Thin (serous) - Rich in minerals - pH value: - Functions: Clearance, buffer system, remineralisation

13 Saliva Salivary Functions The Multiple Functions of Saliva Buffering
Carbonic anhydrases HCO3 Anti-Bacterial sIgA Peroxidases Digestion lipase, amylase mucins Anti-Viral Cystatins Mucins Salivary Functions Anti-Fungal Candida: Histatins Mineralization Ca, Fl, PO4 Lubrication Viscosity Elasticity Mucins Statherins Tissue Coating Mucins, PRPs Amylases Figure adapted from M.J. Levine. 1993

14 Saliva The Major Functions of Saliva Digestion & Taste Protection
Manipulation Dissolve solids Starch digestion (amylase) Gustatory sensation Facilitate chewing Swallowing Bolus formation Buffer - plaque acids (foods) extrinsic acids (reflux) intrinsic acids Antibacterial Oral ecology balance Pathogen defence Mouth clearance/rinsing Food and bacteria Prevent demineralisation Aid remineralisation Hydrates mucous membrane Attachment - Saliva proteins coat enamel surface and allow specific absorption of primary colonisers Food - Saliva may act as a carbon source and select for healthy bacterial balance

15 Biofilm Bacterial Microcolonies Streamers Fluid Channels Flow
©Reeves2013 Streamers Bacterial Microcolonies Fluid Channels Pellicle Tooth Surface Flow Biofilm is a well organized, cooperating community of microorganisms. - A complex community of highly organised bacterial colonies. - Each community contains various types of microorganisms. - Arranged in micro-colonies surrounded by protective matrix. - With a communication system fluid of channels. Biofilm: a well organized, cooperating community of microorganisms. - A complex community of highly organised bacterial colonies. - Each community contains a mix of microorganisms. - Arranged in micro-colonies surrounded by a protective matrix. - With a communication system of fluid channels: Quorum sensing

16 Biofilm 1st Phase: immediately to approximately 4 hours
Formation of aquired pellicle from salivary glycoproteins and maturation. Early colonisation from initial bacteria mainly Streptococcus strains. 2nd Phase: 4 to 48 hours Colonisation of predilection sites, i.e. fissures, iatrogenic retention factors (restorations/overhangs/ortho brackets) and white spots. 3rd Phase: 3 to 7 days Aerobic bacterial metabolic products compromise the hard dental tissues; anaerobic bacterial metabolic products compromise the soft tissues. 4th Phase: 7 to 14 days Mature plaque biofilm is established that consists of sessile bacteria firmly attached to the hard dental tissues and planktonic (floating) bacteria. (König 1987)

17 Biofilm The Formation of Biofilm Quorum sensing Fl- Late Colonizers
T.denticola Fl- AA PG Late Colonizers T.forsythia C.achracea C.sputigena C.gingivalis Salivary receptors in salivary pellicle provide binding matrix for early colonising bacteria. Early colonisers: include: Streptococcus, Actinomyces and Capnocytophaga strains ( in addition to many other early bacteria). Late colonisers include: AA, PG, T.forsythia. T.denticola (amongst others). Late colonisers bind to the early colonisers. Bacteria within the biofilm are able to bind to bacteria of different species. CLICK FOR FL RESISTANCE DEMO: - The biofilm protective matrix makes them resistant to antibiotics, antimicrobials, and host response. Recent research has shown micro-organisms in biofilm can adapt to Fl exposure and become Fl resistant. (Ten Cate 2013) Limiting Fl penetration of the biofilm and salivary pellicle and reducing the protective effects of Fl. A.oris A.israelii A.naeslundii Early Colonizers Strep. oralis Strep. sanguis Strep. mitis Strep. gordonii Statherin -amylase Proline-rich protein Salivary agglutinin Sialylated mucins Fl- resistance Salivary Pellicle Enamel Surface

18 Sugar-Free Gum Salivary Flow Rate Saliva flow rates under stimulation
Saliva flow (ml in 20 min) Un-stimulated saliva Stimulated saliva after chewing paraffin Stimulated saliva after chewing sugar-free gum - Chewing gum increases the saliva flow rate up to 10 times. - “Empty” chewing, without flavor additive (e.g., paraffin), only stimulates up to 5 times. - Chewing sugar-free gum with flavor additive improves flushing and accelerates the removal of soluble compounds. (Edgar 1993)

19 Sugar-Free Gum Salivary Flow Rate
Polyol-sweetened gum stimulates the production of saliva by two mechanisms: - Gustatory stimulation (taste buds) - Masticatory action (periodontal mechanoreceptors) (Dawes and Macpherson. 1992)

20 Sugar-Free Gum Salivary Flow Rate
Salivary stimulation lasts more than 2 hours with SF gum. - Flavour and chewing increase salivary flow. Unstimulated flow rates of less than 0.1 mL/minute are considered evidence of hypo-salivation (Dawes, C., et al. Arch Oral Biol 2004, 49, )

21 Sugar-Free Gum Salivary Flow Rate and Xerostomia*
Sugar-free gum may have benefits in older and medically-compromised patients Chewing sorbitol gum increased saliva flow rates and neutralized plaque pH drop from sucrose in subjects with xerostomia.1,2 - 69% of cancer patients with xerostomia preferred chewing gum to artificial saliva3; 60% of hemodialysis patients preferred gum to saliva substitutes.4 - Gum chewing (12 months, 2x/day) increased stimulated saliva flow rates in 111 frail older people.5 A 6 month study in 186 older (community-dwelling) adults showed significant improvements in plaque and gingival indices, but not saliva flow6; self-perceived oral health status improved significantly in the gum group. Module 2 will discuss the diagnosis, treatment and management of Xerostomia in greater detail. Markovic N; Abelson DC; Mandel ID (1988): Gerodont. 7: 71-75 Abelson DC, Barton J, Mandel ID (1990): J Clin Dent 2: 3-5 Davies AN (2000): Palliat Med 14: Bots CP, Brand HS, et al (2005): Palliat Med 19: Simons D, Brailsford SR, Kidd EAM, Beighton D (2002): J Am Geriatr Soc 50: Al-Haboubi M, Zoitopoulos L, Beighton D, Gallagher JE (2012): Community Dent Oral Epidemiol 40: * Module Two

22 Sugar-Free Gum Oral Clearance Relies on swallowing and flow rate.
Higher salivary flow rate = increased clearance. Unstimulated flow rate < 0.2ml/min = prolonged clearance. Prolonged clearance = greater risk of caries. Greater risk of acid erosion. 15 10 5 0.2 0.4 0.6 0.8 1.0 Unstimulated Flow Rate UNSTFR(ml/min) Halftime(min) Chewing SFGum increases clearance rate and reduces contact time between acidic/sugary foods and the hard tissues. This decreases risk of caries and erosion. Effect of changes in the UNSTFR on the clearance halftime of sucrose Saliva and Oral Health, Edgar M. Dawes C., O’Mullane, D. Eds. 4th Ed, 2012

23 Sugar-Free Gum Buffering Capacity
Fast flowing saliva neutralises plaque (pH value increases). Buffer capacity is the ability to neutralise acids (buffering). The pH value is raised due to the increased concentration of bicarbonate in stimulated saliva. (Bicarbonate increases from 5.47 unstimulated to 16.03mmol/L in stimulated saliva). Increased flow rate exposes hard tissues to low pH for a shorter period. (Flow rate increases from 0.32 ml/min unstimulated to 2.08ml/min in stimulated saliva). Saliva stimulation and buffering of acids by chewing gum pH value 10% sugar solution Chewing gum with sugar substitute Time in minutes (Stoesser 1996) Chewing SFGum increases saliva flow rate and increases pH value of saliva through increased bicarbonate concentrations. This decreases exposure time to acids from food and plaque in addition to increasing the buffering capacity of saliva.

24 Saliva stimulation from chewing gum helps to neutralise plaque acids
Caries Plaque pH Saliva stimulation from chewing gum helps to neutralise plaque acids Factors affecting plaque acids - Fermentable carbohydrates. Oral bacteria produce: Extracellular polysaccharides in the presence of excess sucrose. Glucans increase plaque adhesion and thickness. Fructans produce acid metabolites. Intracellular polysaccharide stores provide ongoing acid production in resting plaque. Plaque pH Time (min) The pH of plaque is raised more quickly following a sucrose challenge. Manning RH, Edgar WM (1993) Brit Dent J 174: 241-4

25 Caries Plaque pH Plaque buffering systems
Bicarbonate is the most important buffering system. Bicarbonate concentration increases with salivary flow. Directly increases plaque pH. Urea from saliva is converted to ammonia by bacteria in plaque with urease activity. Ammonia is highly alkaline and neutralises plaque pH. The intrinsic buffering capacity of plaque. Calcium phosphate crystals in plaque dissolve in acid conditions. Increasing buffering capacity. Bicarbonate diffuses from saliva and neutralises plaque acids Plaque acids diffuse out and are neutralised by bicarbonate in saliva Plaque bacteria convert urea to ammonia Urea from saliva diffuses into plaque Ammonia increases plaque pH Calcium phosphate in plaque Dissolves in acid conditions Increases buffering capacity in plaque ©Reeves2013

26 Caries Demineralisation Demineralisation-Remineralisation
H+ F- Ca++ PO4- Demineralisation Low pH Ca ++ Remineralisation Increased pH Ca++ ©Reeves 2014 - A dynamic equilibrium exists between demineralization and remineralisation. - A neutral pH value promotes remineralisation. When the pH value is <5.5 Calcium (Ca2+) and Phosphate (PO43-) are withdrawn from the dental enamel. Demineralisation - When the pH value is >6.5 Calcium (Ca2+) and Phosphate (PO43-) migrate back into the dental enamel. Remineralisation

27 Caries Demineralisation- Remineralisation
Demineralisation shifts to remineralisation by the use of fluoridation and saliva activation. Saliva provides the medium for remineralisation. Supersaturation of saliva with ionic Ca and Pi, can effectively help remineralise incipient caries lesions. - Fluoride inhibits demineralisation by penetrating and coating enamel crystals to prevent dissolution. - Enhancing remineralization resulting in enamel with a higher Fl content and lower acid solubility.

28 Caries Demineralisation - Remineralisation
©Goulbourn 2012 At a pH value < demineralisation begins. Reversible caries = early enamel lesions Plaque-coated. Frequent fall in pH value below Beginning of demineralisation of the enamel. White spots; surface “pseudo-intact” Image Courtesy Dr F Goulbourn Irreversible caries = dentine caries - Prolonged acid attack. - No remineralisation. Established lesion (manifest caries). Breach of the enamel surface.

29 Redrawn from Featherstone BMC Oral Health 2006 6(Suppl 1):S8
Caries THE CARIES BALANCE PATHOLOGiCAL FACTORS Acid producing bacteria Frequent eating/drinking of fermentable carbohydrates Subnormal saliva flow and function PROTECTIVE FACTORS Saliva flow and components- Fluoride-remineralisation with calcium and phosphate - Antibacterials: chlorhexidine, xylitol CARIES NO CARIES Redrawn from Featherstone BMC Oral Health (Suppl 1):S8

30 Caries Reduction Studies Clinical Caries Studies
Chewing SF gum reduces caries in prospective 2-3 year clinical trials. Clinical Caries Studies - Three year study in children with high caries prevalence showed caries-protective benefit of sugar-free gum (Beiswanger et al. 1998) Three year study, Puerto Rico N = 1402 subjects, age 8-13 Chewed gum 3 x/day for 20 min after meals 7.9% fewer DMFS in all subjects and 11.0 fewer in high-caries subjects. - Another two year study confirmed caries-protective benefit in lower-caries prevalence population (Szöke et al, 2001) Two year study, Hungary n = 547 subjects, age 8-13 Chewed gum 3 x/day for 20 min after meals or no gum Results show 38.7% reduction in DMFS increment after 2 years INCREMENTAL DMFS

31 Reduction of Caries Incidence (%)
Reduction Studies Tabulated Summary of Data from Pertinent Human Intervention Studies Study Intervention (n/N) Control (n/N) Reduction of Caries Incidence (%) Möller 1973 Sorbitol gum 3x/day after meals. 161/313 No gum. 152/313 10% Glass 1983 Sorbitol gum 2x/day. 269/540 No gum. 271/540 2% Kandelman 1990 15% Xylitol gum 90/274 No gum. 97/274 61% 65% Xylitol gum 87/274 66% Mäkinen 1995a Sorbitol gum pellets 2x1.3g, 5x/day 129/1135 No gum. 121/1135 17% 3:2 xylitol/sorbitol pellets, 5x/day 120/1135 44% Mäkinen 1996 Sorbitol stick, 1, 5x/day. 63/471 No gum. 86/471 28% Beiswanger 1998 Sorbitol gum, 3x/day after meals. High risk subjects, intention to treat, 607/1256 No gum. 649/1256 12% Szöke 2001 Sorbitol stick, 3x/day after meals. Including white spots, 269/547 No gum. 278/547 33% Peng 2004 Sorbitol/xylitol/carbamide gum, 4x/day. 363/733 No gum. 370/733 42% Machiulskiene 2001 Sorbitol gum, 5x/day after meals. 68/432 No gum. 80/320 25%

32 Caries Reduction Studies Caries Reduction and Gum - Conclusions
Multiple studies support the anti-caries benefits of sugar-free gum chewed after eating. The majority showed reductions in the range 20-60%. Systematic reviews have also supported this position (eg Mickenautsch et al, 2007; Deshpande and Jadad , 2008) - Studies have been reviewed by expert panels resulting in supporting reviews and statements from regulatory and authoritative bodies (FDA, FDI, ADA, EFSA, etc).

33 Erosion The loss of hard tissue as a result of direct decalcification from acids of non bacterial origin. ©Image Courtesy Dr F Goulbourn

34 Erosion Sources Extrinsic Acidic foods (pH < 5)*
Acidic foods (pH < 5)* Acidic medications (pH < 5) Diet (e.g., frequent acidic food/drink intake. Particularly in the presence lower saliva flow. - Environmental factors (e.g., occupational exposure to acids) * Exception: Yogurt (pH = 4) is not erosive. Intrinsic Gastroesophageal reflux (GERD:backflow of gastric acid into the oral cavity). Vomiting due to: Chronic alcohol abuse Bulimia - Central nervous disorders

35 Often seen in those striving for a healthy lifestyle
Erosion Sources Often seen in those striving for a healthy lifestyle ©Goulbourn 2012

36 Erosion Prevalence ESCARCEL Study Prevalence growing steadily.
Europe has a prevalence rate of 29.4% of young adults having erosive tooth wear. 41.9% demonstrating dentine hypersensitivity. The increasing prevalence of dentine hypersensitivity due to: The longevity of healthy dentition. More frequent daily dietary acid challenges to the tooth surface. Tooth wear risk factors: Associated with frequent acidic food with increased levels of damage. ©Goulbourn 2012 Image courtesy Dr F Goulbourn Bourgeois D, et al ;FDI Annual World Dental Congress, August 2013, Istanbul, Turkey.

37 Erosion Aetiology Appearance of erosions:
©Goulbourn 2012 Appearance of erosions: - Dish-shaped, shallow, rounded edges. - Molar cupping. - On buccal, palatal or incisal dental surfaces. Progress of erosions: - Pain-free onset. - Initially in dental enamel. - Leads to exposed dentine. - Hypersensitivities. - Erosive wear, abfraction. - Opacity to incisal edges. ©Goulbourn 2012 Image Courtesy Dr F Goulbourn

38 Sugar free gum may help prevent erosion and erosive tooth wear*
Remineralisation Sugar free gum may help prevent erosion and erosive tooth wear* Exogenous dietary acids occur at much lower pH values in comparison to plaque acids. - Saliva stimulation from chewing gum: - Increases the rate of mouth clearance from acidic food or drink1. - Stimulates saliva production2. - Increases levels of bicarbonate and calcium ions in saliva3. Aids in more rapid remineralisation of the enamel surface following an acid challenge4. *Initial study suggests salivary stimulation may help5. *Direct clinical evidence pending 1.Trlolo P et al:J Dent Res 1990:69(1Suppl);136 2.Dawes C et al:Arch Oral Biol 2004;49(8): 3.Dawes C et al: Arch Oral Biol. 1995;40: 4.Wefel JS et al:J Dent Res 1989;68(1supp):214. 5. Rios D et al: Caries Res 2006;40:

39 Clinical Assessment Examination Review Medical History
Drugs, medicines. Conditions: Acid reflux, diabetes, vomiting, heartburn, hiatus hernia, Autoimmune diseases (e.g. Sjögren’s syndrome), radiotherapy Soft Tissue Examination Oral hygiene. Periodontal conditions: BOP, pocketing. Soft tissue loss: previous periodontal therapy, surgical/non surgical. Dry/ friable mucus membrane. Lack of saliva pooling. Hard Tissue Examination Exposed root surfaces. Attrition Erosion Abfraction Abrasion Loss of enamel characteristics : shiny,flat surfaces. Caries rate: root surface, proximal. Demineralisation bands.

40 Clinical Assessment Examination Diet
Acids : Food, drinks and frequency. Sugars: Added, hidden and frequency. Timing: Avoid before bed time - reduced salivary flow. Oral Hygiene Tooth brushing technique, bristle type. Toothpaste abrasives. Bacterial acids, plaque scores, demineralisation. Fluoride Exposure Frequency Age appropriate fluoridation Saliva Quality: serous, mucoid, frothy. Quantity: adequate and reaches all areas of the mouth. Buffering capacity.

41 Clinical Assessment Risk Assessment Tools Caries

42 Basic Erosive Wear Examination
Clinical Assessment Risk Assessment Tools Basic Erosive Wear Examination 0 No surface loss Initial loss of enamel surface texture 2* Distinct defect, hard tissue loss less than 50%of the surface area 3* Hard tissue loss more than 50% of the surface area *Dentine is often involved BEWE: a new scoring system for scientific and clinical needs. Clin Oral Investig March; 12(Suppl 1): 65–68. BEWE Index

43 Chairside Testing Saliva 1. Measuring the saliva flow rate (ml/min)
Saliva categories Saliva flow rates (ml/min) Normal flow rate Reduced saliva flow rate Mouth dryness (xerostomia) <0.5 2. Consistency Visual inspection Categories Characteristics Strongly increased viscosity Sticky frothy saliva Increased viscosity Frothy bubbly saliva Normal viscosity Watery clear saliva 3. Measuring the buffer capacity The change in color on the test strip is compared with the sample card and this indicates the buffer capacity: Low Medium High

44 Recommendations H+ F- Ca++ PO4- ©Reeves 2014 Continuous recall with oral hygiene, caries, gingivitis,bleeding index. Regular fluoridation building up a stable fluoride reservoir. Use a less abrasive toothpaste. Only take acidic medications (pH < 5.7) with water. - Diet with a low erosive potential, e.g., vegetables, milk, hard cheese.

45 Recommendations Sugar Free Gum Chew SFG for 20mins after sugar or acid
challenge. Encourage regular saliva stimulation in between meals. Chew sugar free gum, to increase the saliva flow rate. Dental care on the go: chewing sugar free gum can: - Provide mouth clearance - Help prevent plaque accumulation. - Increase saliva buffering capacity. - Decrease plaque pH. - Decrease caries and erosive potential.

46 Conclusions  Saliva is the most important part of the body’s own protective systems for maintaining oral health.  Reduced saliva quantity and quality increase the risk of caries, erosion, xerostomia and interfere with the ecological balance in the mouth.  Informing the patient and activating the saliva’s protective function for the mouth and teeth is the basis of a modern, prevention-oriented treatment strategy.  It has been scientifically proven: saliva stimulation by chewing sugar free gum helps to increase the saliva flow-rate up to tenfold, which can reduce the risk of caries by up to 40%.

47 Thank you! Thank You! 47


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