The dental practice sterilization chain, defined by Portaria n.º 99/2024/1 and the technical standards NP EN ISO 17665-1:2010 and EN 13060, comprises eight sequential stages: decontamination, washing, drying, inspection and maintenance, packaging, sterilization, storage, and traceability. Each stage has precise technical, environmental, and documentation requirements — including the separation of decontamination and sterilization zones introduced in the multi-use medical device reprocessing rules. This guide describes each stage and provides an operational reference aligned with the Portuguese regulatory framework.
The forward-flow principle (dirty → clean → sterile, with no backward movement) is the fundamental concept of reprocessing in dental practices. This unidirectional flow prevents the recontamination of instruments already processed. In Portugal, Portaria n.º 99/2024/1, of 13 March, formalizes the mandatory separation of decontamination and sterilization zones — this is one of the central technical changes introduced relative to the previous regime. Dental practices have until 14 March 2029 to bring their premises into compliance.
Immediately after use, instruments are immersed in a decontamination bath (enzymatic or detergent-disinfectant solution). This step reduces the initial microbial load and protects staff during subsequent handling. Soaking time varies depending on the product used (typically 15 to 30 minutes). Rotary instruments (turbines, contra-angles) follow manufacturer instructions — some require lubrication before cleaning.
Cleaning removes organic residue (blood, saliva, debris) that would prevent effective sterilization. Two methods are commonly used in Portuguese dental practices: the ultrasonic bath (cavitation cleaning, effective for hollow and articulated instruments) and the thermal washer-disinfector (automated, reproducible, recommended for high-volume practices and compliant with NP EN ISO 15883). Manual brush cleaning remains acceptable but is less reproducible and carries a higher risk of sharps injuries.
After cleaning, instruments are rinsed with clean water (ideally reverse osmosis or demineralized water to avoid limescale deposits) then thoroughly dried. Drying is an often-overlooked but essential step: wet instruments in a pouch compromise the sterility of the packaging. Drying can be done with medical-grade compressed air or a single-use lint-free cloth. In regions with hard water (common in much of Portugal), demineralized water is particularly important to prevent mineral buildup that can damage instruments and autoclave chambers.
Each instrument is visually inspected (residual contamination, functional condition, corrosion) before packaging. Instruments are placed in sterilization pouches (heat-resistant paper/plastic) appropriate to their size. Pouches are sealed by heat sealing. The sterilization date and cycle number must appear on each pouch — this marks the beginning of traceability.
Pouches are placed in the autoclave following loading guidelines (do not overload, do not stack pouches). In Portuguese dental practice, the Class B autoclave (NP EN 13060) is the practical standard — the only class capable of sterilizing hollow and wrapped instruments. The standard cycle is 134°C with appropriate holding time (extended for the prion cycle). Before the first load of the day, a Bowie-Dick or Helix test validates proper autoclave function.
At the end of the cycle, the autoclave produces a report containing the recorded parameters (temperature, pressure, holding time). This report is the cornerstone of traceability — it proves that sterilization conditions were achieved. The ERS inspection form (mod-133_02) explicitly verifies the automatic or mechanical recording of these parameters.
Dental turbines, contra-angle handpieces, and ultrasonic scaler tips are hollow instruments — steam must penetrate internal channels to ensure sterilization. This is why a Class B autoclave (with pre-vacuum cycle) is the practical standard: Class N autoclaves do not reliably sterilize hollow instruments.
The prion cycle (134°C with extended holding time) applies to all instruments in contact with at-risk tissues. Turbines require particular attention: lubrication per manufacturer's instructions before cleaning, use of the Helix test (not Bowie-Dick) to validate steam penetration into channels, and individual packaging in appropriately sized pouches. A failed Helix test means hollow instruments in the load are not sterilized — even if the autoclave report shows "cycle passed." For details on autoclave testing, see the biological controls guide.
Sterilized pouches are stored in a clean, dry space, away from dust and direct light. The use-by date depends on the packaging type and storage conditions — in practice, from 1 to 6 months depending on the packaging. A pouch whose integrity is compromised (torn, opened, wet) must be repackaged and resterilized.
For details on calculating the use-by date, see our dedicated guide.
Traceability is the step most practices neglect — and the first one inspectors from ERS and IGAS check. Each autoclave cycle must be documented: date, time, program, result, operator, loaded instruments. The link between the patient, the instruments used, and the sterilization cycle must be established and verifiable. Portaria 99/2024/1 and the ERS inspection form (mod-133_02) require automatic or mechanical recording of cycles.
This is precisely what SecuSteri does: the autoclave report is imported automatically, the operator selects the instruments in the load, validates with their PIN code, and the traceability record is generated. QR labels link each pouch to its cycle.
Skipping pre-disinfection (dried residue is much harder to remove during cleaning). Packaging instruments that are still wet. Overloading the autoclave (prevents steam from reaching all surfaces). Breaking the forward flow (placing clean instruments on a contaminated surface). Not documenting cycles (a missing or incomplete register is the leading cause of findings during ERS and IGAS inspections).
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