Taste disturbance in two patients after dental anesthesia by inferior alveolar nerve block

A Systematic Review on Nerve-Related Adverse Effects following Mandibular Nerve Block Anesthesia

Inferior alveolar nerve (IAN) block injections are commonly used in clinical practice, but they are not free from complications. The aim of the present systematic review is to assess the nerve-related adverse effects of IAN block anesthesia. A structured and systematic search was performed on the major electronic databases (PubMed, Cochrane Library, Web of Science, Scopus and CINAHL) for studies published in English until 30 September 2021. A total of 131 articles were identified through database searching using combinations of keywords. Fifteen papers were included and assessed for eligibility. Overall, nerve damage following an IAN block anesthesia injection is a rare occurrence, probably due to the direct nerve trauma of the needle, a neurotoxic effect of the used anesthetic solution and/or a combination of them. From a medico-legal point of view, a balanced discussion prior to nerve block anesthesia should be pursued in order to avoid patients' reluctance to undergo necessary dental treatment due to the remote eventuality of nerve injury.

The Etiologies and Considerations of Dysgeusia: A Review of Literature

BACKGROUND

Dysgeusia is a prevalent qualitative gustatory impairment that may affect food intake and quality of life. The facial (VII), glossopharyngeal (IX), and vagus (X) nerves are the three cranial nerves responsible for sensing taste. Typically, dysgeusia is considered a general term for all taste disorders. In addition, dysgeusia may be a symptom of underlying systemic conditions such as diabetes mellitus, chronic kidney disease, respiratory infections, and nutritional deficiencies. Various subjective and objective diagnostic approaches are available to aid clinicians, each with its own set of benefits and drawbacks.

HIGHLIGHTS

Taste impairment can lead to a lack of enjoyment while eating, food aversion, and malnutrition, resulting in a decrease in the quality of life and loss of muscle mass. Therefore, the present review aims to address the probable etiologies, diagnostic aids, and management of dysgeusia. A broad search for studies was conducted using PubMed, Web of Science, Scopus, and Google Scholar. In addition, relevant studies found in the references of the selected articles were also studied.

CONCLUSION

Oral health care providers should be aware of the possible etiologies of dysgeusia, diagnostic tools, and treatment options. Accurate diagnosis of the cause of taste dysfunction has a significant impact on the management of taste impairment.

Sweet-Tasting Ionic Conjugates of Local Anesthetics and Vasoconstrictors

Local anesthetics are widely utilized in dentistry, cosmetology, and medicine. Local anesthesia is essential to providing a pain-free experience during dental and local surgeries as well as cosmetic procedures. However, the injection itself may produce discomfort and be a source of aversion. A novel approach toward the taste modulation of local anesthetics is proposed, in which the anesthetics of the “-caine” family serve as cations and are coupled with anionic sweeteners such as saccharinate and acesulfamate. Ionic conjugates of vasoconstrictor epinephrine such as epinephrine saccharinate and epinephrine acesulfamate have also been synthesized. Novel ionic conjugates were developed using anion exchange techniques. Reported compounds are sweet-tasting and are safe to use both topically and as injections.

The Impact of Aging and Medical Status on Dysgeusia

Disorders of taste and smell can cause an aversion to food in a sick patient and therefore affect his/her ability to maintain optimal nutrition. This can lead to a reduced level of strength, muscle mass, function, and quality of life. Additionally, reduced ability to differentiate between various intensities or concentrations of a tastant can result in increased intake of salt and sugar and exacerbation of chronic diseases such as heart failure and diabetes. These implications can be heightened in the elderly, who are particularly frail and are challenged by polypharmacy and multiple comorbid conditions. In this article, we will review the prevalence, etiology, and management of taste disorders. Additionally, we will review the association between taste and smell disorders and how disorders of smell can affect perception of taste.

Postoperative alterations in taste and smell

Context:

Alterations in taste and smell, including but not limited to anosmia, ageusia, hypogeusia, and dysgeusia, have been described in association with various medications, including anesthetic agents. Frequently, these symptoms occur 1-2 weeks after medication administration and last several months. While such a phenomenon is a rare occurrence, it nonetheless can significantly impact patients’ satisfaction and quality of life.

Evidence Acquisition:

The methodology consisted of a thorough literature search using the MEDLINE and Cochrane databases utilizing keywords such as anosmia, ageusia, olfactory disorders, postoperative, and anesthesia.

Results:

Our results yielded several previously published case report, and were not limited to a specific type of anesthesia. Based on available literature, we review the physiology of taste and smell as well as the medications associated with loss of these senses. We describe perioperative agents that could lead to postoperative complications associated with anosmia and and ageusia.

Conclusions:

Based on available literature recommendations for anesthesiologists caring for patients at risk for this occurrence are presented in this review. The symptoms are usually temporary as in the majority of the patients the sensory receptor cells are able to regenerate themselves after injury. Anesthesia providers need to aware of this phenomenon to be able to reassure patients and possibly avoid anesthetic techniques associated with anosmia and ageusia.

Iatrogenic injury of the chorda tympani: a systematic review

Objective:

To review the currently available literature on iatrogenic injury of the adult chorda tympani.

Design:

Systematic literature review.

Method

Five electronic databases and one search engine were used to access available English language literature on the chorda tympani, focusing on iatrogenic injury.

Results:

The chorda tympani is most often injured during middle-ear surgery, after which at least 15–22 per cent of patients experience symptoms, mostly changes in taste and dryness of the mouth. Numerous factors influence whether injury to the chorda tympani causes symptoms, including the extent of injury, type of surgery, age of the patient, anatomical variables and subjective adaptation. Although most patients experience gradual symptomatic recovery, complaints can be persistent and troublesome.

Conclusion:

Care should be taken to preserve the chorda tympani during middle-ear surgery, and to warn patients pre-operatively about this potential complication. This is particularly important if surgery is bilateral.

Self-reported severity of taste disturbances correlates with dysfunctional grade of TMD pain

Altered central neural processing of sensory information may be associated with temporomandibular disorders (TMD) pain. The objectives of this study were to compare the prevalence of self-reported taste disturbances in TMD pain patients and in a control population, and to determine whether frequency of taste disturbances was correlated with dysfunctional grade of TMD pain. Subjects were 2026 people within a German population sample and 301 consecutive TMD patients diagnosed using the Research Diagnostic Criteria. Taste disturbances were measured using two questions from the Oral Health Impact Profile. Dysfunctional grade of TMD pain was measured with the Graded Chronic Pain Scale. A two-sample test of proportions revealed that TMD patients reported a greater frequency of taste disturbances, 6%, than did the general population subjects, 2% (P < 0.001). Moreover, the frequency of taste disturbances correlated with the dysfunctional grade of TMD pain. For each 1 unit increase in taste disturbance, the odds of observing a higher grade of TMD pain increased by 29% (95% CI: 3-63%, P = 0.03). Analysis by individual taste question and adjustment for age and gender did not substantially affect the results. These findings are consistent with a central neural dysfunction in TMD pain and suggest that a common neural substrate may underlie sensory disturbances of multiple modalities in chronic pain patients. Further research regarding taste disturbances and trigeminally mediated pains such as in TMD is warranted.

Gustatory function after microlaryngoscopy

CONCLUSION

Quantitative gustatory alterations are rare after microlaryngoscopy (MLS), whereas transient qualitative taste distortions occur more often. Patients undergoing MLS should know that mild but transient qualitative taste disorders may occur.

OBJECTIVE

Suspension MLS requires neck extension and tongue compression. Little is known about taste disorders following MLS. To investigate qualitative and quantitative gustatory function after MLS we tested and questioned patients before and several weeks after the MLS.

SUBJECTS AND METHODS

This was a prospective controlled study carried out in a tertiary care centre. Forty-three patients participated, 33 of whom underwent MLS and 10 septoplasty. Tongue compression time was recorded during MLS. Patients received taste evaluation before and at 1 and 14 days after the intervention. Patients were asked to indicate subjectively changed taste perceptions.

RESULTS

Psychophysical (quantitative) taste results showed no significant differences before and at 1 and 14 days after the intervention (p = 0.60). Tongue compression time (MLS group) had no influence on measured post-MLS taste scores. In the MLS group four patients reported distorted taste perception the day after the MLS, whereas no patient in the septoplasty group did so. In all, four patients distorted taste perception, had disappeared after 14 days.

Unilateral atrophy of fungiform papillae associated with lingual nerve injury

The lingual nerve is at risk of injury during common dental procedures because of its proximity to the inferior alveolar nerve and the roots of the third molar tooth. Lingual nerve injury has been documented following extraction of wisdom teeth, dental anesthetic injections, and other endodontic procedures. We present a case of loss of somatosensory function and taste associated with the intriguing finding of fungiform papillae atrophy as a result of lingual nerve injury.

Taste deficits related to dental deafferentation: an electrogustometric study in humans

Dental treatments, the prevalence of which increases with age, can cause orofacial somatosensory deficits. In order to examine whether they may also affect taste sensitivity, electrogustometric thresholds were measured at 9 loci on the tongue surface in 391 healthy non-smoking, non-medicated subjects. Results showed that the greater the number of deafferented teeth, the higher the thresholds. Irrespective of age, subjects with more than 7 deafferented teeth exhibited significantly higher thresholds than subjects with fewer than 7 deafferented teeth. Conversely, across age groups, no statistical difference was observed among subjects with no, or few, deafferented teeth. Hence, a taste deficit, which was not correlated to aging, was observed. An association was noticed between the location of taste deficits and the location of deafferented teeth. Higher thresholds at anterior sites, with no possible traumatic injury relationship, suggested that neurophysiological convergence between dental somatosensory and taste pathways - possibly in the nucleus tractus solitarius - could be responsible for these relative decreases of taste sensitivity when dental afferences were lacking. Among trigeminal contributions, lingual nerve and inferior alveolar nerve may synergize taste.