Prion diseases implications in dentistry/ dental implant courses
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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
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
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
- 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.
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.