Contraindications for Local Anesthetic Techniques in Dentistry

Contraindications for Local Anesthetic Techniques in Dentistry

In this chapter, we review cases and circumstances in which dental local anesthetic cannot be administered. These include the following:

  • Lack of patient cooperation.
  • Very poor health (ASA IV).
  • Severe coagulopathies.
  • Injection site infection.
  • Severe restricted mouth opening (trismus, ankylosis of the temporomandibular joint).

In many situations where local anesthesia is contraindicated, we can turn to deep sedation or general anesthesia. In other cases, the patient’s underlying condition must be treated first.

Lack of Cooperation from the Patient

A lack of patient cooperation is a contraindication for dental local anesthetic, since it can entail very serious consequences for both the patient and the dentist, as follows:

  • Pricks and injuries in the patient’s mouth and face.
  • Pricks on the dentist’s hands.
  • Breakage of the needle in the patient’s mouth (Bacci et al. 2012).

Predisposing Factors

Certain situations and types of patients are more likely to generate poor behavior, for example:

  1. Preschool children under aged 5–6 years (pre‐cooperators) (Wright et al. 1991; Sharaf 1997; Tyrer 1999; Lind‐Strömberg 2001). Owing to their immaturity, they cannot understand the need to cooperate with the dentist (Pinkham and Schroeder 1975).
  2. Patients with mental conditions, such as those with Down syndrome or cerebral palsy (Pinkham and Schroeder 1975; Tyrer 1999; Hulland and Sigal 2000), for the same reason as mentioned above, i.e., inability to cooperate, although this depends on the severity of the condition.
  3. Patients with mental and psychiatric disorders (Berggren and Meynert 1984; Moore et al. 1993; Hulland and Sigal 2000), such as the following:
    • autism (Hulland and Sigal 2000; Lind‐Strömberg 2001)
    • acute neurosis (Scott et al. 1984; Hägglin et al. 2001)
    • schizophrenia (Seeman and Molin 1976)
    • drug addiction and alcoholism (Pinkham and Schroeder 1975; Berggren and Meynert 1984)
    • psychotropic drug use (Berggren and Meynert 1984; Hulland and Sigal 2000)
    • phobias (Hägglin et al. 2001).
  4. Patients with severe anxiety when receiving dental treatment. In these cases, we can highlight a series of characteristics:
    • Basic anxiety. Around 10% of people have high levels of anxiety with respect to dental treatment (Table 8.1), although they attend their appointments and try to cope with their anxiety to complete treatment (Molin and Seeman 1970; Kleinknecht and Bernstein 1978; Hall and Edmondson 1983; Scott et al. 1984). A further 5% have phobias or experience uncontrolled irrational and extreme fear (Table 8.1). Patients with phobias are not generally problematic with respect to dental work since their systematic avoidance behavior will result in many canceled or broken appointments. Often, these patients only attend the dentist’s office when their neglected dental needs have mushroomed into a frank dental emergency such as an abscess, seeking acute dental treatment and possibly analgesics and antibiotics (Ayer et al. 1983; Sokol et al. 1985; Locker and Liddle 1991; Moore et al. 1993). To overcome their anxiety, these patients may benefit from psychological treatment or possibly sedation or general anesthesia (Moore et al. 1993).
    • Dental local anesthesia is the factor that causes the highest levels of anxiety in patients undergoing dental treatment (Lautch 1971; Gale 1972; Meldman 1972; Berggren and Meynert 1984; Scott et al. 1984; LeClaire et al. 1988). Seeing the syringe and needle, and feeling the prick of the needle are the most anxiety‐inducing components of dental treatment.
    • The behavior of anxious adults differs very little from that of those who are not anxious (McGimpsey 1977; Kleinknecht and Bernstein 1978; Ayer et al. 1983; Scott et al. 1984), therefore the health questionnaire should include a direct question on fear of dental treatment by category, for example five categories (no fear to very frightened) to identify patients with high degrees of anxiety (Kleinknecht and Bernstein 1978; Scott and Hirschman 1982; Ayer et al. 1983).
  5. A history of behavioral problems and complications in previous situations, such as in dental treatment, vaccination, venipuncture for blood sampling, etc. Such behavior is thought to reoccur in around half of patients with such a history (Persson 1969; Hannington‐Kiff 1969; McGimpsey 1977; Edmondson et al. 1978), therefore an appropriate question should be included on the health questionnaire.

Table 8.1 Patients who experience anxiety when undergoing dental treatment.

Level of anxiety
Reference Low Medium High Phobia
Freidson and Feldman (1958) 5%
SIFO (1962) 9–14%
Gatchel et al. (1983) 71% 17% 5% 6%
Scott et al. (1984) 44% 25% 21% 10%
Rankin and Harris (1984) 65% 21% 8% 6%
Lindsay et al. (1987) 63% 22% 10% 5%
Milgrom et al. (1988) 80% 13% 4% 3%
Stouthard and Hoogstraten (1990) 39% 40% 18% 4%
Locker and Liddle (1991) 8% 4%
Hakeberg et al. (1992) 59% 25% 11% 5%
Moore et al. (1993) 60% 30% 6% 4%
Kaakko et al. (1998) 39% 41% 17% 4%
Ragnarsson (1998) 72% 19% 10% 0.3%
Hägglin et al. (2001) 17%
Average 11.2 5.7%
Rounded average 10% 5%

Percentages rounded to whole units.

Evaluation of Risk

The best way of evaluating the risk of poor behavior is at the first visit, as follows:

  • Review the patient’s health questionnaire to obtain answers to the following questions:
    1. How anxious and fearful does dental treatment make you?

      Not at all ◻ A little ◻ Moderate ◻ Quite a lot ◻ A lot ◻

    2. Have you ever experienced an abnormal reaction, dizziness, or fainting at the dentist’s office or with administration of local anesthetic, vaccinations, blood donations, etc.? Yes ◻  No ◻
    3. Are you being treated for any medical conditions? (Open answer)
    4. What medications are you taking, including prescription, over‐the‐counter, or herbal supplements? (Open answer)
    5. Do you use alcohol, tobacco, or any other substances? (Open answer)

    The first two questions have already been commented on above, the last three provide us with information on the mental and psychiatric status of the patient, as well as about his/her medical problems and current medication to determine whether there are absolute or relative contraindications for administration of dental local anesthetic.

  • The clinical examination at the first visit provides us with information on the risk of poor behavior, especially in the case of children since they are brought by their parents. Therefore, apart from age and physical appearance, there are two key moments for predicting disruptive behavior at future visits to the dentist:
    • During the oral examination.
    • During intraoral radiography.

Difficulty performing these two maneuvers points to a high risk for administration of local anesthesia at subsequent visits. In contrast, if the examination reveals that the patient has undergone major restoration work and complicated dental procedures and the parents report no special measures having been taken (sedation, medication, etc.), then the patient is likely to behave well since he/she has been able to undergo the above‐mentioned treatments.

Approach to Behavioral Problems

Patients with behavioral problems can be divided into two groups:

  • Patients who can receive local anesthetic but for whom this is very problematic (e.g., patients who experience vasovagal syncope, etc.). In these cases, local anesthesia should be supplemented with methods to reduce anxiety, such as a good psychological strategy based on management of the personal relationship with the dentist (Gale et al. 1984; Maggirias and Locker 2002) and conscious sedation with short‐acting benzodiazepines (triazolam) and/or nitrous oxide. However, such techniques are beyond the scope of this book.
  • Patients who cannot receive local anesthetic. These patients require general anesthetic, and adults may require psychological or psychiatric care (Moore et al. 1993).

ASA IV Physical Status

In 1963, the American Society of Anesthesiologists (ASA) developed a classification of physical status, which is now known as the ASA classification (Anonymous 1963; ASA 2019). This was initially designed to evaluate the threat to life of patients undergoing general anesthesia, although since it was introduced it has been extended to locoregional anesthesia and sedation, as is the case in dentistry (Malamed 2007, 2010). In this classification, we can observe the following:

  • Some physicians consider patients with two or more conditions to have a higher ASA level than that of each of the conditions individually. For example, a patient with obesity and a stomach ulcer who is aged more than 65 years (all ASA II conditions) is classed as ASA III because of the fact that he/she has three conditions. ASA II means that the systemic illnesses are well‐controlled. ASA III by definition means the conditions are not controlled. There is a degree of subjectivity among clinicians and some will consider a patient with multiple well‐controlled comorbidities as ASA III, but the author adheres to the definition of ASA II as well‐controlled systemic diseases.
  • This classification of patients changes over time. For example, a patient who has had a myocardial infarction less than 3 months previously is classed as ASA IV, although if he/she has recovered after 3 months and subsequent progress is good, then he/she can be considered ASA III. If the condition continues to improve, the patient can be considered ASA II.

Below, we describe each of the ASA levels and provide examples, with emphasis on how local anesthesia is contraindicated in ASA IV cases.

ASA I Patients

  • Definition: healthy patients, no smoking, no or minimal alcohol use (ASA 2019).
  • Consequences: good tolerance of physical stress (pain) and psychological stress (anxiety).
  • Relevance in dentistry: can receive local anesthetics and standard dental treatment with no danger.

ASA II Patients

  • Definition: patients with well‐controlled systemic disease that does not cause limitations.
  • Consequences: minor limitations to tolerance of physical stress (pain) and psychological stress (anxiety).
  • Relevance in dentistry: can receive local anesthetics and standard dental treatment.
  • Examples include but not limited to:
    • Healthy patients with special circumstances, such as:
      • Pregnancy in a healthy woman (Malamed 2007, 2010; ASA 2019).
      • Healthy persons aged >65 years (Malamed 2007, 2010).
      • Obesity, body mass index (BMI) 30–40 (McCarthy 1982; Jastak et al. 1995; ASA 2019).
      • Patients who smoke tobacco (McCarthy and Malamed 1979; Abraham‐Inpijn et al. 1988).
      • Social alcohol drinker (ASA 2019).
    • Cardiovascular disease:
      • Controlled arterial hypertension (90–95/140–160 mmHg) (Abraham‐Inpijn et al. 1988; Malamed 2007; ASA 2019).
      • Congestive heart failure (caused by myocardial infarction, vascular disease, rheumatic disease, etc.) that is moderate and does not cause limitations. This is also said to be compensated congestive heart failure (Malamed 2007).
      • More than 6 months after a cerebrovascular accident that did not leave neurological sequelae.
      • Chronic orthostatic hypotension with vertigo or dizziness (Malamed 2007).
    • Endocrine‐metabolic diseases:
      • Well‐controlled diabetes (Malamed 2007, 2010; Wilson et al. 2008; ASA 2019).
      • Well‐controlled hypo‐ or hyperthyroidism, i.e., normal function (euthyroid) (McCarthy 1982; Malamed 2007, 2010; Wilson et al. 2008).
      • Plasma pseudocholinesterase deficiency (Malamed 2003).
    • Respiratory disease:
      • Well‐controlled asthma (Malamed 2007, 2010; Wilson et al. 2008).
      • Nonacute upper airway disease (common cold, influenza) (Malamed 2007).
      • Chronic sinusitis (McCarthy and Malamed 1979).
    • Central nervous system (CNS) disease:
      • Well‐controlled epilepsy with uncommon seizure episodes (less frequent than once every 3 months) (Malamed 2007; Wilson et al. 2008).
      • Psychiatric disorders such as controlled depression (Jastak et al. 1995).
      • Extreme fear of dental treatment (phobia) (McCarthy and Malamed 1979; Malamed 2007). These patients may require deep sedation or general anesthesia. Local anesthesia may be contraindicated.
    • Other diseases:
      • Rheumatic diseases with chronic joint problems (arthritis, etc.) that do not require corticosteroids (Malamed 2007).
      • Stomach ulcer (McCarthy 1982; Malamed 2007).
      • Increased intraocular pressure (glaucoma) (McCarthy 1982; Malamed 2007).
      • Allergy to drugs, foods, or latex (McCarthy 1982; Malamed 2007).

ASA III Patients

  • Definition: patients with severe or uncontrolled systemic disease that limits activity but is not incapacitating (no symptoms at rest or with normal exercise).
  • Consequences: reduced tolerance to physical stress (pain) and psychological stress (anxiety).
  • Relevance for dentistry: patients can receive local anesthetic and standard dental treatment. However, it is important to take into account the following:
    • If in doubt, the patient’s doctor should be consulted.
    • The patient may require additional measures such as sedation to reduce anxiety (oral, intravenous, intramuscular drugs, inhaled nitrous oxide, hypnosis), antibiotics, etc. Treatment of medically compromised patients is beyond the scope of this book. Excellent texts are available on this subject. Here, we only address the use of locoregional anesthetic in ASA III patients.
    • ASA III patients, especially those with cardiovascular disease, do not present further severe complications (arrhythmia, angina pectoris, myocardial infarction, etc.), although they do have increased minor complications such as tachycardia, dizziness, shaking, etc. It is therefore recommended that appointments do not exceed 30 minutes, where possible, since the number of complications can increase if the session is longer (Hughes et al. 1966; Daubländer et al. 1997).
    • Some authors suggest using vasoconstrictor‐free anesthetic solutions. However, this is somewhat problematic because pain – a key factor in ASA III patients – is not well controlled. Anesthetic solutions with epinephrine should be used with caution (see Chapter 10).
  • Examples include but are not limited to:
    • Patients with special circumstances, such as:
      • Morbid obesity (BMI > 40) (ASA 2019).
      • Alcohol dependence or abuse (ASA 2019).
      • Active hepatitis (ASA 2019).
    • Cardiovascular disease:
      • Uncontrolled arterial hypertension with moderate blood pressure values of around 95–115/160–200 mmHg (McCarthy 1982; Abraham‐Inpijn et al. 1988; Malamed 2007, 2010).
      • Congestive heart failure (caused by myocardial infarction, vascular disease, rheumatic disease, etc.) with breathing difficulty (dyspnea) during exercise or with nervous tension, although not at rest. This is decompensated congestive heart failure (Malamed 2007).
      • Implanted pacemaker (ASA 2019).
      • More than 3 months after any of the following:
        • Cerebrovascular accident that has left neurological sequelae (McCarthy and Malamed 1979; Malamed 2007, 2010; Wilson et al. 2008).
        • Heart attack (angina pectoris or acute myocardial infarction) (McCarthy and Malamed 1979; Abraham‐Inpijn et al. 1988; Malamed 2007, 2010; Wilson et al. 2008).
        • Coronary bypass surgery (Perusse et al. 1992a).
        • Stents in coronary artery disease (ASA 2019).
      • Heart transplant: surgical denervation resulting from removal of the nerve endings in the heart leaves the heart hypersensitive to the action of catecholamines (Carleton et al. 1969; Roca et al. 1993; Meechan et al. 2002).
      • Clotting disorders:
        • Platelet count >30 000–50 000 (Finucane et al. 2004; Scully and Cawson 2005).
        • Oral anticoagulants (warfarin, acenocoumarol) with international normalized ratio (INR) levels <3.5–4 (Table 8.3).
        • Hemophiliac patients with clotting factor >30–50% (we can assume that clotting factor has been added) (Evans and Aledort 1978; Segelman 1978; Katz and Terezhalmy 1988; Jastak et al. 1995).
    • Endocrine‐metabolic diseases:
      • Poorly controlled diabetes (Malamed 2007, 2010; Wilson et al. 2008; ASA 2019).
      • Poorly controlled symptomatic hypo‐ or hyperthyroidism (Greenwood and Meechan 2003; Malamed 2007, 2010).
    • Respiratory diseases:
      • Poorly controlled asthma (Malamed 2007: Wilson et al. 2008).
      • Poorly controlled chronic obstructive pulmonary disease (bronchitis, emphysema) with no breathing difficulty (dyspnea) in habitual daily activities (Malamed 2007; Wilson et al. 2008).
    • CNS diseases:
      • Epilepsy controlled by drugs but with fewer than one seizure episode per month (Malamed 2007).
    • Kidney diseases:
      • More than 3 months after a kidney transplant.
      • Chronic kidney failure requiring regular hemodialysis (Malamed 2007; ASA 2019).
    • Other diseases:
      • Rheumatic disease with chronic joint problems (arthritis, etc.) requiring corticosteroids (Malamed 2007).
      • Cancer treated on an outpatient basis.
      • Myasthenia gravis (rare disease involving skeletal muscle weakness) that is stable and mild or moderate (Patil et al. 2012).
      • Malignant hyperthermia. Patients who have had this disease.
      • Patients who have received radiation on the maxillofacial area at risk of osteoradionecrosis.

ASA IV Patients

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Feb 17, 2024 | Posted by in Oral and Maxillofacial Surgery | Comments Off on Contraindications for Local Anesthetic Techniques in Dentistry

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