Dental Management
It is important to determine the best method for communicating with the patient that ensures that they understand when explaining oral hygiene techniques, dental procedures and treatment plans (Table 3.2.1; Figure 3.2.3)Figure 3.2.3 Orthodontic treatment for a patient with craniofacial dysostosis and associated hearing loss (Treacher Collins syndrome).
Section II: Background Information and Guidelines
Definition
Deafness is the difficulty or inability to use the sense of hearing due to a partial (hearing loss) or total (cophosis) unilateral or bilateral loss of auditory capacity. It is estimated that 7% of the population has an incapacitating hearing loss. Deafness affects men and women equally, and its prevalence increases with age. The condition is classified according to the anatomical area where the injury is located, the degree of hearing loss and the age at onset (Table 3.2.2).
Aetiopathogenesis
The most common causes for conductive auditory deficit are congenital craniofacial disorders, infections and trauma (Table 3.2.3)Table 3.2.1 Considerations for dental management.Risk assessmentDepending on the onset, degree of hearing loss, type and aetiology, (may impact on intellectual development) and/or the capacity for expression and speechCochlear implants are susceptible to electromagnetic interference and can be damaged by excessive electricity, including monopolar diathermy in the head and neck region or bipolar diathermy within 2 cm of the implantCoexistence of other diseases which have led to the hearing lossCriteria for referralReferral to a specialised clinic or hospital centre is rarely required and will be determined by the presence of comorbidities (e.g. polymalformative syndromes)Access/positionDistrust of dentists and anxiety are commonSome patients with auditory deficits can experience positional vertigo (e.g. Ménière syndrome)CommunicationPatients with mild deficits, those who wear hearing aids/cochlear implants and those who can lip read:Stand/sit at an appropriate distance from the patientPosition yourself where the patient can clearly see your face/lipsTalk with the face uncovered or use a transparent facemaskKeep the head fixed and talk slowly without raising the tone of voiceSpeech should be adapted to the patient's sociocultural level and ageIf possible, avoid intermediaries in the conversationPatients with severe auditory deficit (untreatable):Use other senses (vision and feel) to facilitate communicationUse mirrors, models, drawings and written languageUse sign language if you are able to (although it is not universal) or mimeUse a sign language interpreter if appropriateConsent/capacityIn order to confirm that the patient understands all the information that appears in the consent form and can ask any questions they have, select the most appropriate communication system to be employed (use a sign language interpreter if necessary)For those who also have a visual deficit, it is essential additional adaptations are in place (e.g. consent form printed in sufficiently large type or a Braille version available)If the patient cannot read, a close family member/friend acting as a witness can read it for them if hearing is sufficientIf it is not possible for the patient to communicate their decision using alternative adjuncts/methods, a best interest decision may be requiredAnaesthesia/sedationLocal anaesthesiaThere are no specific considerationsSedationThere may be difficulties monitoring the level of consciousness when performing conscious sedationGeneral anaesthesiaEnsure that the chosen method of communication is effective and communicated to all the theatre and recovery staffDental treatmentBeforeBackground noise should be reduced as much as possibleEnsure lighting is adequate to allow the face to be clearly seenConsider the use of signs and pictures to communicateTransparent facemasks and face shields help lip readingDuringThe ‘tell–show–feel’ (physical contact) technique may be appliedRotary and ultrasonic instrumentation can cause interference with hearing aidsElectrocautery should not be employed in patients with cochlear implantsDrug prescriptionAminoglycoside antibiotics and macrolides are ototoxic and should be avoidedA number of drugs such as metronidazole, clindamycin and indomethacin can cause reversible hearing disorders (e.g. tinnitus)Education/preventionOral hygiene is frequently poor, and oral hygiene habits are often inadequateEffective communication is a key factor in oral health education plansIn view of this, some countries have proposed requiring sign language in their dental curriculumDietary counselling is essential (high consumption of sugar and carbonated drinks has been described among patients with deafness)Table 3.2.2 Auditory deficit classification.CategoryClassificationLesion locationConductive or transmissive hearing loss (external ear, middle ear and labyrinth)Sensorineural or perceptive hearing loss (internal ear, auditory nerve and temporal lobe)MixedDegree of hearing lossMild (detects sounds between 25 and 29 dB)Moderate (detects sounds between 40 and 69 dB)Severe (detects sounds between 70 and 89 dB)Profound (detects sounds above 90 dB)Age at onsetPrelingual (before the development of speech)Postlingual (after the development of speech)Table 3.2.3 Auditory deficit aetiology.AgeClassificationPrenatalInfections (rubella, syphilis, toxoplasmosis, HIV)HypothyroidismHypertensionOtotoxicityGenetic (craniofacial dysostoses, family history)Polymalformative syndromesPerinatal/neonatalPrematurityLow birthweightTraumaInfections (herpes simplex, cytomegalovirus)Jaundice (kernicterus)HypoxiaChildhoodInfections (otitis media, mumps, measles, malaria, meningitis)AdolescenceOtotoxicityForeign bodiesExposure to noiseTraumaMénière syndromeAdulthoodPresbycusisOtotoxicityOtosclerosisInfections (otitis media, encephalitis, meningitis)Figure 3.2.4 An audiogram shows the quietest sounds a patient can just hear.
Sensorineural deafness is commonly associated with genetic disorders, trauma, prematurity, infections, tumours, drug ototoxicity, otosclerosis and presbycusis, among others
Clinical Presentation
The symptoms of auditory deficit depend on the cause and level of hearing loss
The presence of comorbidities is in general more common when the auditory deficiency occurs during the prenatal or perinatal stage
Children younger than 4 months do not turn face to noises; at 12 months, they are unable to articulate a single word and only respond when they can see the speaker or when certain sounds are produced
Older children talk in a high voice, continuously interrogate the speaker, and their pronunciation is unclear
Sudden loss of hearing can be a symptom of another disease, such as stroke
Diagnosis
Initial examination with tuning fork and otoscopeFigure 3.2.5 Cochlear implants in a child with congenital deafness.
Audiometry (auditory capacity curve that combines intensity and frequency) (Figure 3.2.4)
Impedance (audiometry of electrical response or otoacoustic emissions)
Tympanometry and measurement of the stapedial reflex
Management
Conductive auditory deficits can generally be treated with drugs or surgery (e.g. drainage, tympanoplasty and