Prion diseases implications in dentistry/ dental implant courses

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Transcript of Prion diseases implications in dentistry/ dental implant courses

  • Prion Diseases-Implications In Dentistry

  • PRION DISEASESGroup of fatal neurodegenerative disorders affecting humans and animalsNo host response Long incubation periods

    TSE in Brain

  • Prions??? Stanley Prusiner-Nobel Prize in Medicine 1997

    Normal proteins in all mammalian tissues

    helical structure- Located on short arm of chromosome 20

    No nucleic acid

    Help in copper metabolism, signal transduction and cell adhesion

    Active role in regulation and distribution of acetyl choline

  • Pathogenesis

  • So what?? Mutation of PrPC PrPSc

    Very resistent to sterilization procedures

    Insoluble, proteinase resistant, highly infectious molecule

    Gives rise to TSE( transmissible spongiform encephalopathies) in humans and BSE, scrapie in animals.

  • How it effects humans??

    SporadicInheritedTransmissible:Foodstuffs Direct contact

    Perinatal Iatrogenic

    Beef, Milk, Animal protein, Yogurt

    Handling of meat, infected animal products

    Hormones, bone grafts, vaccines,Corneal transplant, cross contamination

  • Not only is this protein used in the food, it is in the products we use everyday such as cereal bars, lipstick and hand lotion and garden fertilizers, yogurt and breath mints

  • Any relation with Dentist ???Causative!!!? or Risk?? / Both?

    Potential area of cross

    contamination Resistant to sterilization Bone grafts Surgical handling of risk group

    Oral infectivity Saliva is a risk factor?? Tonsils, posterior border of tongue, trigeminal ganglion are potential sources Gingiva has its highest presence

  • Diseases caused:Animals HumansCongenitalAcquiredSporadicFamilialGSSKuruvCJDIatrogenicBSEScrapie

  • EPIDEMIOLOGY First described in United States Has spread to UK, Asia and Europe. World wide: 400 cases

    UK : 114 cases France : 23 cases India : 30 cases Reports of exports of infected products from India Emerged as major concern and challenge to health care professionals

  • Sporadic/ Classical CJD: Congenital, 85% of cases Effects middle aged or elderly Characterized by- Rapidly progressive multifocal dementia- Ataxia, myoclonus- Evident EEG changes- Speech loss and finally death

    Transmissible Spongiform Encephalopathies Kuru Acquired Cannibalistic activity Women and young adults are effected Long incubation period

  • VCJD Effects adolescents and young adults Associated with intake of infected animal products Long course of illness Hallucinations, dysphagia, dysarthria, paraesthesia, Delirium, dementia and akinesia Ameloid deposition in lymphatic tissue Absence of EEG changes

    Transmissible Spongiform Encephalopathies

  • Transmissible Spongiform Encephalopathies Iatrogenic TSESpecial interest to Dentist.Risk of cross infection from instrumentsMost of infections occurred afterNeurosurgeryDuramater transplantCorneal grafting, growth hormone, xenogenic grafts, tonsillar surgeryManipulation of post 1/3 of tongue

  • Oral manifestations of prion diseasesMost common manifestations: - Dysphagia (may be initial symptom)

    - Oro-facial Paraesthesia/ dysesthesia

    - Dysarthria

    - Motor incoordinations

    - Involvement of trigeminal ganglion

  • Diagnosis & TreatmentInvestigative procedures:

    - EEG, MRI, CSF analysis - Autopsy is definitive


    - No proper treatment is available - Invariably fatal90% of deaths usually occur within one year of diagnosis, difficult to confirm diagnosis until post mortem.

  • Prevention & Infection controlBest method- avoidance of contactA complete medical, family and travel historyInfectivity of the tissue:Brain, Spinal chord, Eye Liver, Lungs, Spleen, Lymphnodes, Placenta, Gingiva, Tonsils

  • Prevention & Infection controlAdvisory committee on Dangerous pathogens:

    General infection control practices are sufficient if the work does not involve neurovascular tissue

    Proper infection control measures in high risk pts involving invasive procedures

    Single use items-disposable needles, gloves safest

    Quarantining the instruments, linen, gowns, gloves and masks in rigid leak proof combustible waste container-incinerate

  • Prevention & Infection control No use of animal derived graft procedures unless certified

    Autoclaving the instruments at 134oc for 18 min

    Schedule the risk pt appointment at the end of the day

    Avoid activating water lines

    Disposable bowl instead of spittoon

  • Study by Sogal et al assessed the possibility of transmission of TSE from xenogenic bone substitute in periodontal and oral surgical procedures. The risk was found to be insignificant if strict sterilization protocols were followed.

    A study by Blanquet-grossard showed the risk of iatrogenic contamination by endodontic surgery could not be rejected.

    However several case control studies found no relation between tooth extraction, dental surgery and other dental procedures with human TSE.

    Supporting evidences

  • Conclusion

  • References

    1. Stephen RP. Prion disease and possible implications for oral care. JADA 2003;134:1486-91.

    2. Begena PS, Esparza, Julian CT. Implications of prion diseases for dentistry-an update. OOOE 2008;105:316-20.

    3. Stephan RP. Prions and Dentistry. J R Soc Med 2002;95:178-181.

    4. Amir A .Prions in dentistry-what are they? Should we be concerned? What can we do? JCDA 2006;72(1):53-60.

    5. Christine LW. Variant CreutzFeldt Jacob disease-a problem for general practitioner? Prim Dental Care 2002; 9(3):95-9.

    6. Smith AJ, Bagg J. Prions and oral cavity. J Dent Res 2003;82(10):769-75.

  • Thank you