ADEX Dental Hygiene common mistakes
ADEX Dental Hygiene · Understand the traps and how to avoid them.
Records probing depths and bleeding on probing but never converts them to clinical attachment level, then labels a site with 3 mm of recession and a 3 mm probing depth as 'healthy' or 'gingivitis only.'
Probing depth is the first number students record and the gingival margin is charted on a separate line; the subtraction (PD + GM = CAL) is easy to skip under time pressure, and PD alone cannot distinguish attachment loss from a shallow sulcus with a coronally positioned margin.
What to do instead
Physically write the equation at every site: PD + GM = CAL, using a negative sign for recession. Then apply the staging anchors out loud until automatic: Stage I = 1-2 mm interdental CAL, Stage II = 3-4 mm interdental CAL, Stage III/IV = 5 mm or more interdental CAL, with tooth loss and complexity factors deciding between III and IV.
Reaches for a sickle scaler or a universal curette to debride a deep posterior pocket, then uses the same universal instrument on the mesial and distal of the same tooth without changing adaptation.
The instruments look similar in the cassette and sickle scalers feel efficient on heavy supragingival calculus, so students carry a supragingival habit subgingivally where the thick tip and 90-degree edge lacerate tissue.
What to do instead
Memorize the design triad: sickle scaler = 90-degree edge, triangular cross-section, supragingival only; universal curette = 90-degree edge, semicircular cross-section, two cutting edges, both surfaces of any tooth; Gracey curette = 70-degree edge, curved shank, one cutting edge, area-specific. State which surface and which tooth the instrument was designed for before answering.
Describes the layers of the pulp from the outside inward in the wrong order, for example naming the cell-free zone of Weil or the cell-rich zone as the layer directly adjacent to the predentin.
The three subodontoblastic layers are memorized as a list rather than as a spatial sequence, so the names are recalled without a position, and the odontoblast layer, which is the actual interface with dentin, gets pushed inward.
What to do instead
Anchor the order to dentin: odontoblastic layer (pseudostratified, lining the predentin) then cell-free zone of Weil then cell-rich zone then the pulp core. Draw the four bands once per study session so position, not just the name, is stored.
Selects levonordefrin (1:20,000) or an epinephrine-containing cartridge for a patient taking a nonselective beta-blocker or a tricyclic antidepressant without flagging the pressor interaction, and answers that no precaution is needed because 'the dose is small.'
Students learn 'aspirate and limit dose' as a universal rule and stop there, so drug-specific interactions with the vasoconstrictor are never attached to the rule.
What to do instead
Build a two-column table: vasoconstrictor on the left, interacting drug class on the right. Fix these pairs: levonordefrin plus nonselective beta-blocker is the classic severe pressor interaction; epinephrine plus tricyclic antidepressant or nonselective beta-blocker requires limiting to roughly 0.04 mg epinephrine (about two 1:100,000 cartridges) with aspiration; untreated severe hypertension or pheochromocytoma is a reason to defer elective care.
Computes the maximum recommended dose by dividing the patient's weight by the cartridge volume, or assumes every cartridge contains the same milligram dose regardless of the anesthetic's percent concentration.
The arithmetic is done from memory in the exam instead of from the fixed conversion, so 2% lidocaine and 4% articaine get treated as interchangeable when they differ by a factor of two in milligrams per cartridge.
What to do instead
Use the conversion every time: mg/mL = percent x 10; mg per 1.8 mL cartridge = percent x 18. So 2% lidocaine = 36 mg, 3% mepivacaine = 54 mg, 4% articaine = 72 mg, 4% prilocaine = 72 mg, 0.5% bupivacaine = 9 mg. Calculate cartridges = (mg/kg maximum x weight in kg) divided by mg per cartridge, and state the answer in whole cartridges rounded down.
Answers that increasing kVp increases subject contrast (makes the image more black-and-white) and that mA controls contrast, or recommends lowering kVp as the way to reduce patient dose.
The two exposure controls are taught together and get swapped; 'more power equals more contrast' feels intuitive even though the actual relationship runs the other way.
What to do instead
Lock the pair with one sentence each: kVp controls quality, penetration, and contrast, where higher kVp gives lower contrast, a longer gray scale, and lower patient dose; mA controls quantity of photons and therefore density, with exposure time affecting density too. Any answer that raises contrast by raising kVp, or lowers dose by lowering kVp, is wrong.
Assigns every patient the same six-month recall and the same fluoride varnish schedule regardless of caries risk, and withholds sealants from high-risk patients because 'the tooth might be about to erupt or exfoliate.'
The six-month default is a habit absorbed from practice rather than a risk-based decision, and sealant hesitancy comes from conflating a partially erupted or primary tooth with a contraindication.
What to do instead
Answer caries questions through the risk category first: identify risk level, then set the interval and agents from it. High risk means a shorter recall, varnish two to four times per year, and sealants on pits and fissures of at-risk permanent and primary teeth, including partially erupted molars with moisture control; low risk gets a longer interval and no additional agents beyond community or home fluoride.
Classifies a reading such as 128/84 mm Hg as 'normal' or 'prehypertensive' and proceeds with elective treatment without stating a follow-up or referral threshold.
Older 120/80 and 'prehypertension' categories linger in memory, and students compare only the systolic number to a remembered cutoff instead of evaluating systolic and diastolic independently.
What to do instead
Recite the current categories from the higher of the two numbers: normal under 120 and under 80; elevated 120-129 and under 80; stage 1 = 130-139 or 80-89; stage 2 = 140 or higher or 90 or higher; crisis = over 180 and/or over 120. Then state the action: stage 1 or 2 means refer for medical evaluation, and 180/120 or above means defer elective care and arrange immediate medical consultation.
Answers an ethics item by naming the wrong principle for the scenario, for example calling a competent adult's refusal of radiographs or periodontal therapy a failure of beneficence that must be overridden, or breaching confidentiality because a family member asked.
The four principles are memorized as a list without a trigger for each, so students default to the word that sounds most clinical ('do good') even when the scenario is about self-determination.
What to do instead
Attach one trigger phrase to each principle: autonomy = competent patient decides, including informed refusal (document it, offer alternatives, do not abandon); beneficence = act in the patient's interest; nonmaleficence = avoid harm; justice = fairness and allocation. For confidentiality items, disclose only with consent or where a legal reporting duty applies, and never to a family member on request alone.
Wipes a visibly contaminated operatory surface with a disinfectant towelette as the only step and moves to the next patient without allowing the label contact time, or reprocesses a scaler with an intermediate-level disinfectant instead of sterilization.
Wiping looks like cleaning, so the separate detergent step and the wet contact time are treated as optional, and the critical versus semicritical device distinction is not applied at the point of reprocessing.
What to do instead
Classify the item first, then choose the process: critical items that touch bone or penetrate mucosa (scalers, curettes, forceps, handpieces, surgical burs) require cleaning followed by sterilization; semicritical items touching intact mucosa require sterilization or high-level disinfection. For housekeeping surfaces, use the sequence clean with detergent, then apply an EPA-registered hospital disinfectant, and leave it visibly wet for the full label contact time before use.