Wednesday, September 2, 2015
By Alok Dubey, MD Endotracheal intubation is crucial in cases that require general anaesthesia and airway management during surgical procedures. Many serious complications are associated with endotracheal intubation, such as hypoxemia, soft tissue damage to the pharynx and dental damage. Diseased teeth are at particularly high risk, but healthy teeth can also be injured. This paper highlights the importance of a thorough preoperative assessment of the patient’s dental status, including the recognition of vulnerable teeth and associated anaesthesia risk factors in the prevention of perioperative dental damage.
Dental injury is the most common of all forensic claims related to anaesthesia. The maxillary teeth are generally prone to injury (74.3%), especially those on the left side (41.7%). Laryngoscopy is a major factor for the insult because during laryngoscopy, the anterior teeth are often unintentionally used for support . Maxillary anterior teeth tend to be restored with bonding, veneers, or crowns making them even more prone to damage as these restorations are not as resilient as natural teeth. Another complicating matter is that porcelain, the restorative material of choice, is not easily recognized as being artificial .
Considering the magnitude of the problem and the physical, economic and legal consequences of dental injury in anaesthesiology, it is important to assess the dental state and the degree of difficulty to be expected in intubating the patient.
Minimizing dental injuries begins with the anaesthetists preoperative assessment of the patient’s oral health including dentition. Dental examination should especially include an assessment of the patient’s upper incisors—the teeth most likely to be injured during the perioperative period—for pre-existing damage. Preoperative notes should record any damages or missing teeth .
Documentation of the patient’s preoperative dental condition and informing the patient about the potential dental damage will diminish costs for any related postoperative dental treatment. Upon discovery of a potentially hazardous dental condition, a consultation with a dentist should be considered before proceeding with the surgical procedure. Whilst there is no standardized method for recording this, a simple diagram and a brief written description may be satisfactory. The patient should be warned of the potential for dental damage and its incidence. Any existing conditions such as chips or missing teeth must be noted [1, 3].
All risk factors, both anaesthetic and dental, should be identified and explained to the patient. Certain pre-conditions like dental caries, periodontal disease, restored teeth, presence of crowns, or fixed partial dentures increase the risk of the teeth to injuries. Dental trauma results from the coupling of a compromised dentition with a physical event such as pressure or forces applied to a tooth [3,4].
Periodontal disease leads to alveolar bone loss. Loss of bone support results in tooth mobility. In patients with severe periodontal disease, even the placement of an oral airway or a laryngeal mask might provoke a dental luxation .
During the preoperative assessment, the anaesthetist should enquire about loose teeth, unstable crowns, veneers, bridgework, and any intraoral prosthesis (dentures or orthodontic appliances) .
Some age groups also predispose teeth to such injuries. Children in the age group of 6-8 years are susceptible to the loss of maxillary teeth during endotracheal intubation due to the prevalence of immature roots, increased overjet, ectopic eruptions, dilacerated roots, or pathology .
Dental injuries occur primarily in the 50–70-year age group, which is probably a result of the higher incidence of periodontal disease in this age group. The incidence of dental injuries is approximately five times higher in patients with a pre-existing dental condition .
Anterior crowding increases the likelihood of damage and isolated teeth appear to be at particular risk. Generally, one tooth is damaged; however, injuries of two, three, and even four teeth have been reported .
Chronic use of medications can adversely affect dental and periodontal health. Drugs with anticholinergic activity cause dry mouth (xerostomia). This condition is also one of the most common complaints following radiation therapy for head and neck cancers and leads to hyposalivation-induced rampant caries. For such patients and in the elderly, root decay that usually presents along the gingival margins of the teeth (i.e., the junction of where a tooth emerges from the gums) can cause the crown of the tooth to be severed perioperatively . When patients present with significantly loose teeth, they are usually aware of their mobility but may not admit it because of embarrassment or their underestimation of the condition’s potentially significant perioperative implications. For any suspiciously susceptible teeth noted preoperatively by the anesthesiologist, it is suggested that he or she puts on a glove and slightly wiggles them to better appreciate their mobility .
The presence of any intraoral appliances should also be confirmed during the preoperative assessment of this patient population. Devices used for breaking the childhood habits of tongue thrusting and thumb sucking often suspend from the hard palate and may interfere with laryngoscopy. Adolescents (and adults) may present with orthodontic appliances that are removable, such as a biteplate (retainer) or fixed such as brackets (braces). Another fixed appliance known as a palatal expander is designed to promote widening of the maxilla. This device can limit the space available for a laryngoscope and can increase the likelihood of dental damage or a traumatic intubation .
Appreciating the relationship of a patient’s two jaws (i.e. maxilla and mandible) and the existence of any T.M.D. is beneficial. Moreover, the biting surfaces of particularly anterior teeth should be carefully scrutinized, any incomplete dental treatment should be verified, and removable prostheses such as dentures should be removed, labeled and stored .
Dental factors that make the tooth more prone to iatrogenic injury have been tabulated in table1.
Dental injury mostly happens during tracheal intubation, and it is more frequent in case of poor dentition and/or difficult laryngoscopy as occurs in case of restricted mouth opening, macroglossia, retrognathism, prominent incisors, shortened thyromental distance, limited neck extension, and so forth [6, 7].
Blade-tooth contact is extremely frequent in patients with reduced mouth opening or with Mallampati higher than II . Patients with an interincisor gap ≤ 3.5 cm have been found to have a higher risk of dental injury compared with patients with an interincisor gap > 3.5 cm . Pre operative examination should take into consideration these factors to assess the degree of difficulty in intubating the patient.
Recognition of dentition which is at risk for injury should alert the anaesthetist to seek a preoperative dental consultation. Communication of these risks to the patient should form part of the informed consent.
Vulnerable dentition may force the anaesthetist to consider the use of fiberoptic bronchoscopy, video laryngoscope, lighted stylets or the complete avoidance of tracheal intubation. The use of nasopharyngeal airways instead of oropharyngeal airways may also reduce the risk of dental injury .
Table 1: List of tooth related risk factors for Oro- dental injuries to occur during tracheal intubation/laryngoscopy.
|Tooth related risk factors for Oro- dental injuries|
|Children aged 5–12 years.
(Age when primary tooth shedding occurs)
Geriatric age group with periodontitis.
|Grossly decayed tooth/teeth.
Rampant caries in children/Post radiotherapy in elderly.
|Inflammation of gums.
Gingival recession & Alveolar bone loss.
|Large anterior filling.
Crowns, veneers or fixed partial dentures.
|Protruding upper anterior teeth.|
|Extensive tooth surface loss.|
|Tooth structural abnormalities:
I. Amelogenesis imperfecta.
II. Dentinogenesis imperfecta.
|Anterior teeth crowding.
|Previously traumatized tooth.
|Non vital tooth.
Root canal treated tooth.
Dubey A., M.D.S (Pediatric dentistry), Associate professor *
Department and institution:
* Department of Pedodontics & Preventive dentistry, College of Dentistry, Jazan University, Jazan, Saudi Arabia.
Name: Dr. Alok Dubey.
Address: Associate professor, Department of Pedodontics & Preventive dentistry, College of Dentistry, Jazan University, Jazan, Saudi Arabia.
Phone number: 00966505815277
E-mail address: email@example.com
Preanesthetic dental evaluation to avoid oro-dental injuries- a brief review