Is the re-use of sterilized implant abutments safe enough? (Implant abutment safety)

Mª Angeles Sánchez-Garcés 1 , Marta Jorba 2 , Joan Ciurana 3 , Miguel Vinas 4 , Mª Teresa Vinuesa 5

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Despite only a few laboratories in the world are undertaking experimental work with prions, notably that of Stanley B. Prusiner (Nobel Prize in Physiology or Medicine, 1997), the work has led to several major concerns (14).

The first and most relevant in the current context is that prions need to be completely inactivated using harsher conditions than those used against bacteria and viruses. To ensure prion inactivation, the thermal sterilization should be combined with chemical treatment. It would appear that procedures used for routine sterilization of surgical instruments cannot inactivate prions (15,16), which already led to the development of new and more stringent recommendations for reprocessing instruments and these should eventually be applied to abutments (17). This has been reinforced by the discovery that prions that are responsible for bovine spongiform encephalitis (BSE) can be up to 1 million times more difficult to inactivate than the most commonly used hamster prions; thus, one cannot exclude the possibility that human prions are also much more resistant than the laboratory prions (10). These recommendations are based on conventional autoclaving (121ºC) combined with chemical attack; this may be achieved by autoclaving in the presence of 1 M sodium hydroxide, or by soaking in 2% bleach for 1 h. Such treatments are extremely corrosive and may cause irreversible damage to the surface of abutments (18). Prevalence of asymptomatic Creutzfeldt-Jakob disease (CJD) in UK population in people born from 1941 to 1985 is 1:2000 and prion iatrogenic transmission (blood transfusions, organ transplants and surgical instrumentation) is therefore possibility. Another source of prions could be bovine bone substitutes used widely for bone regeneration after or simultaneously to the dental implant placement. These materials keep some proteins, their manufacturing processes are not guaranty to the inactivation of the prion, and in consequence, Kim et al. (19) suggest abolishing the use of bovine bone.

The presence of organic carbon reported in our study means that organic material originating in the patient is adhered to the surface and, subsequently, the presence of prions cannot be ruled out.

In conclusion, we believe that, despite costs, the practice of reusing implant abutments should be abandoned, since it cannot be demonstrated to be safe enough.

Further studies trying to identify the source of the organic carbon adhered in the abutments are needed. In addition, it is worth elucidating if there could be any safe procedure to effectively remove all the organic material present in the titanium surfaces of the reused healing abutments.

http://www.medicinaoral.com/medoralfree01/aop/22967.pdf

HUNTERS, CWD TSE PRION, THIS SHOULD A WAKE UP CALL TO ALL OF YOU GUTTING AND BONING OUT YOUR KILL IN THE FIELD, AND YOUR TOOLS YOU USE...

* 1: J Neurol Neurosurg Psychiatry 1994 Jun;57(6):757-8

Transmission of Creutzfeldt-Jakob disease to a chimpanzee by electrodes contaminated during neurosurgery.

Gibbs CJ Jr, Asher DM, Kobrine A, Amyx HL, Sulima MP, Gajdusek DC.
Laboratory of Central Nervous System Studies, National Institute of
Neurological Disorders and Stroke, National Institutes of Health,
Bethesda, MD 20892.

Stereotactic multicontact electrodes used to probe the cerebral cortex of a middle aged woman with progressive dementia were previously implicated in the accidental transmission of Creutzfeldt-Jakob disease (CJD) to two younger patients. The diagnoses of CJD have been confirmed for all three cases. More than two years after their last use in humans, after three cleanings and repeated sterilisation in ethanol and formaldehyde vapour, the electrodes were implanted in the cortex of a chimpanzee. Eighteen months later the animal became ill with CJD. This finding serves to re-emphasise the potential danger posed by reuse of instruments contaminated with the agents of spongiform encephalopathies, even after scrupulous attempts to clean them.

PMID: 8006664 [PubMed - indexed for MEDLINE]

http://jnnp.bmj.com/content/57/6/757.long

SATURDAY, MARCH 16, 2019

Medical Devices Containing Materials Derived from Animal Sources (Except for In Vitro Diagnostic Devices) Guidance for Industry and Food and Drug Administration Staff Document issued on March 15, 2019 Singeltary Submission

https://bovineprp.blogspot.com/2019/...materials.html


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