Frequency And Level Of Dental Injury Related To Conventional Direct Laryngoscopy: A Prospective Observational Study
Conditions: Asa I-III Patients, Intubated Patients, Laryngoscopy
Sponsor: Selcuk University

Official Title: Frequency And Level of Dental Injury Related to 
Conventional Direct Laryngoscopy: A Prospective Observational Study
NCT Number: NCT06760247
Document Date: January 6, 2025
Frequency And Level of Dental Injury Related to Conventional Direct 
Laryngoscopy: A Prospective Observational Study
Funda ARUN1, Bahar OC2, Oguzhan ARUN2, Ahmet Emin SONMEZ2, Özlem 
TAS2, Nimet UNLU3
1 Selcuk University Faculty of Dentistry Department of Pedodontics, Konya, 
Turkey
2 Selcuk University Faculty of Medicine Department of Anesthesiology and 
Reanimation, Konya, Turkey
3 Selcuk University Faculty of Dentistry Department of Restorative Dentistry, 
Konya, Turkey
Corresponding Author
Funda Arun, MD, Assistant Professor. 
Selcuk University Faculty of Dentistry
Department of Pedodontics
Alaaddin Keykubat Kampus Selcuklu Konya
Tel: 0090 532 7494542
Email: funda.arun@selcuk.edu.tr

Introduction
Direct conventional laryngoscopy is an essential skill in airway management 
for endotracheal intubation. Although the majority of direct laryngoscopies are 
uneventful in experienced hands, it can be difficult and challenging in some 
situations such as limited mouth opening, limited mandibular protrusion, 
narrow dental arch, decreased thyromental distance, modified Mallampati 
class 3 or 4, decreased submandibular compliance, decreased sterno-mental 
distance, limited head and upper neck extension, and increased neck 
circumference (1,2). Due to these challenging situations, complications may 
occur due to unintended teeth, lips, gingiva, and oral tissue damage during 
laryngoscopy, particularly in patients with difficult intubation (3). 
Dental injury is not only one of the most common complications in the oral 
cavity during laryngoscopy but also an important part of medicolegal claims 
against anesthetists (4,5). Enamel infractions or fractures, loosened or 
subluxated teeth, tooth avulsion, and crown or root fractures are commonly 
reported dental injuries with an incidence as high as 38.6% (6). Unfortunately, 
complications may still occur even in patients without known predictors of 
difficult intubation and some of these injuries are microscopic and cannot be 
noticed by the clinicians and diagnosed after the patients’ complaints (5). 
Thus, dental damage may occur more often than estimated. 
Visual inspection and radiography are the conventional diagnostic methods in 
the dental practice. However, with these methods, it is not always possible to 
diagnose dental problems in depth and definitively. Transillumination as a 
diagnostic tool in medicine refers to light transmission through parts of the 
body. 
Fiber-optic 
transillumination 
(FOTI) 
and 
near-infrared 
light 
transillumination (NILT) are the additional detection methods used for the 
diagnosis and assessment of dental caries (7). FOTI of teeth is an easy, 
well-tolerated, non-invasive, and non-irradiating technique and has been used 
for over 100 years (8). 
This study aims to investigate especially minor dental traumas and associated 
damages instead of major traumas that can be directly seen due to 
conventional laryngoscopy using transillumination technique with cold light 
source. 

Material and Methods
After the approval of the Selcuk University Local Institutional Ethics 
Committee (2017/05), 300 ASA I-III adult patients who underwent elective 
surgical operations under general anesthesia and underwent endotracheal 
intubation were included in this prospective, double-blinded study. Written 
informed consent was obtained from each patient during the preoperative 
anesthetic evaluation. 
During the preoperative anesthetic evaluation, an anesthetist and dentist in 
the study team performed a detailed oral physical examination on all study 
patients. Demographic data such as age, gender, body weight, height, data 
related to airway management such as mallampati score, thromental distance, 
mouth opening size, and information about past anesthesia history, including 
previously described difficult intubation and medical condition, were 
questioned, and recorded. During a dental examination, all teeth, but 
particularly anterior 6 of maxillary and mandibular teeth, were examined 
regarding general dental hygiene and the existence of any missing teeth, 
tooth decay, plaque and stone formation, discoloration, gum problems such as 
recession and gingivitis, and tooth trauma. The patients with the presence of 
deformation due to a trauma or a congenital abnormality in the maxilla-fascial 
region, a swinging tooth, and a history of previous surgical operation 
regarding the maxilla-fascial region and oral cavity were not included in the 
study.
All patients were subjected to the same anesthetic process. None of the 
patients were given anesthetic premedication on the day of surgery. 
Anesthesia induction was achieved with 2.0 mg.kg-1 iv propofol, 2.0 mg.kg-1 iv 
fentanyl, and 0.6 mg.kg-1 iv rocuronium after routine monitoring with ECG, 
non-invasive blood pressure, and SpO2. Each patient was ventilated with a 
face mask with 100% O2 for 2-3 minutes and intubated with a proper 
endotracheal 
tube 
by 
the 
same 
anesthetist using a conventional 
laryngoscope. All intubations were achieved by anesthesiologists with 
different statuses (senior assistants and consultants who were blind to the 
study). After the endotracheal intubation, the anesthesiologist included in the 
study recorded the data about intubation and airway management such as 

Cormack-Lehane Score, laryngoscope blade type and size, difficulty in 
intubation, use of additional devices such as oral airway, intubating 
supraglottic airway device, video laryngoscope, and intubating guide in the 
airway management, and the number of intubating attempts by asking the 
practitioner. 
The intraoperative dental evaluation was performed using a transillumination 
technique with a cold light source at two different time points: T1: Before 
anesthesia induction, and T2: After endotracheal intubation, before the start of 
the surgical operation. The same dentist performed all dental evaluations. 
Although all teeth were evaluated, the evaluation with the cold light source 
was particularly for every six teeth in the lower and upper jaws. 
Statistical Analysis
The statistical analysis was performed using SPSS, version XX. The normality 
of continuous variables was assessed with the Kolmogorov-Smirnov test. 
Descriptive statistics were presented as mean ± standard deviation (SD) or 
median (interquartile range, IQR) for continuous variables and as frequency 
(n) and percentage (%) for categorical variables. Group comparisons were 
made using the Independent Samples t-test, Mann-Whitney U test, One-Way 
ANOVA, or Kruskal-Wallis test, depending on the data distribution. Categorical 
variables were compared using the Chi-square test or Fisher’s exact test. The 
relationship between intubation variables and dental trauma was analyzed 
using logistic regression, and results were reported as odds ratios (OR) with 
95% confidence intervals (CI). Paired sample t-tests or Wilcoxon signed-rank 
tests were employed to compare dental evaluations before and after 
intubation. A p-value < 0.05 was deemed statistically significant.

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