INTRODUCTION: Barometric pressure variation during dives may induce barodontalgia and barotrauma. Barodontalgia refers to oral pain resulting from a change in ambient pressure. The aim of this study was to investigate the occurrence of barodontalgia and dental barotrauma among French civilian scuba divers.
METHODS: A nationwide cross-sectional internet-based survey was conducted among French scuba divers over 18 yr of age registered by the French Federation of Underwater Sports (FFESSM). The online questionnaire was distributed from October to December 2020. It contained questions regarding general characteristics of participants, barodontalgia and dental barotrauma occurrences, and relationship of the diver with his/her dentist.
RESULTS: There were 684 scuba divers (65.4% men; aged 48 ± 12 yr) who participated in the study. Barodontalgia was reported by 18.7%, with some respondents reporting more than one episode. Most barodontalgia affected posterior (81.2%) and upper teeth (55.2%) with dental filling (50.0%). At least one dental barotrauma was reported by 10.1% of respondents, including mainly loss or fracture of a dental filling (4.2%). The occurrence of dental barotrauma was significantly higher among men (12.3%) than women (5.9%) and increased significantly with the age, the years of diving and the diving qualification.
CONCLUSION: Information should be provided to divers on the importance of routine dental checkups.
Gougeon K, Yasukawa K, Baudet A. Barodontalgia and dental barotrauma among scuba divers. Aerosp Med Hum Perform. 2022; 93(5):421–425.
Scuba (self-contained underwater breathing apparatus) diving is widely practiced across the world for recreational and occupational purposes. Scuba diving-related injuries in the head and neck are extremely common due to pressure fluctuations 19 and constant jaw clenching. 13 They include disorders of the ears, nose, sinuses and orofacial structures like temporomandibular joint (TMJ) pain, facial muscle fatigue, nerve baroparesis, mouth dryness, and dental pain or injury. 3,29 The diving mouthpiece may also be a vector for herpes complex virus transmission when it is exchanged between divers, 24 and induce tooth fracture when it involves excessive occlusal pressure on a weakened tooth. 11
Barodontalgia, also called “tooth squeeze”, is a barometric pressure-induced oral (dental or nondental) pain in an otherwise asymptomatic organ. 31 Barodontalgia occurs in pilots at an altitude below 3000 m and in divers mainly at a water depth ranging from 18 to 24 m. 2 Dental-induced (direct) barodontalgia is intimately related to pre-existing dental pathology (i.e., dental caries, pulpitis, pulp necrosis, and apical periodontitis) and faulty restorations. Nondental-induced (indirect) barodontalgia results from a pressure change induced pathologic condition not related to teeth, i.e., facial barotrauma. It includes middle ear and sinus barotraumas. 31 The stimulation of the superior alveolar nerves by the sinus barotrauma may generate dental pain involving the posterior maxillary teeth. 17 Severe barodontalgia during a dive may suddenly incapacitate a diver or cause an incident related to the pain (for example, missed decompression stops 25 ), which could jeopardize the diving safety. 14 The exact mechanism of barodontalgia is not yet fully understood, but it seems to be explained by three main hypotheses: 1) changes of volume of trapped air bubbles, under a root or dental filling, may stimulate nociceptors either in the periodontal tissues, dentin or pulp; 2) nociceptors in an infected maxillary sinus with its ostium closed may be stimulated by tensions in the tissues generating pains referred to the teeth; and 3) by stimulation of nerve endings in chronically inflamed pulp. 16
Dental barotrauma refers to a dental mechanical alteration like tooth fractures (also called “barodontocrexis”), dental filling fracture, and decreased retention of a dental filling or crown up to this dislodgement. 32 Dental barotrauma may or may not be followed by pain. 30 Barotrauma is directly related to Boyle’s law which states that, if temperature remains constant, the volume of a fixed mass of an ideal gas is inversely proportional to the pressure of the gas. When the diver descends deeper below the water surface, pressure exerted by the water increases (the barometric pressure is 1 atm at ground level and diving pressure increases by 1 atm every 10 m) and reduces the volume of gases in enclosed spaces such as teeth and sinuses. 17 When the diver ascents, the atmospheric pressure decreases, the trapped gases expand, and teeth may be damaged. 7
Several studies assessing the dental symptoms prevalence were conducted in the countries of the Arabian Peninsula among civilian 1,27 and military divers. 2,3 A few studies were conducted among recreational divers in the USA and in Australia, 15,25,26 and among professional divers in Europe. 9,10,33 In France, the occurrence of barodontalgia was studied among 1317 military divers, 9,10 and among 1184 military and civilian pilots and aircrew members. 18 Military divers are an atypical minority among divers. In France, there are 2000 military divers 10 compared with 140,000 divers registered by the French Federation of Underwater Sports (FFESSM) in more than 2000 diving centers. It was hypothesized that barodontalgia was less common among military divers in comparison to civilian divers due to higher frequency of routine dental examination and medical follow-up conducted by physicians qualified in diving medicine among military divers. 9 To the authors’ knowledge, no study was conducted among French civilian and recreational divers. The aim of this study was to investigate the occurrence of the dental symptoms (barodontalgia and dental barotrauma) among French civilian scuba divers.
METHODS
Subjects
A cross-sectional survey on the occurrence of barodontalgia and dental barotrauma was conducted among civilian scuba divers in France. An on-line questionnaire was self-administered on Google® Form from late October to early December 2020. Two methods of invitation were employed: e-mails sent to scuba divers of several diving centers and message on a French diver Facebook group called “La plongée et ses accidents, comment tenter de les prévenir”. To be included, divers over 18 yr old should be registered by the FFESSM and be certified to at least level 1 of a diving qualification (corresponding to supervised diving up to 20 m). This study was approved by the Ethics Committee of the University Hospital of Nancy. The participation was voluntary and noncompensatory. Anonymity was guaranteed at all phases of data collection and analyses.
Procedure
The questionnaire was composed of three parts. Part one included questions about age, gender, city in which the diver was registered in a diving center, years of diving experience, FFESSM diving qualification (level 1: supervised diving up to 20 m; level 2: autonomous diving up to 20 m and supervised diving up to 40 m; level 3: autonomous diving up to 60 m; level 4 and above: divemaster and scuba instructor) and numbers of dives performed in the lifetime (1 to 20; 21 to 40; 41 to 60; 61 to 80; 81 and more). Part two consisted of questions concerning barodontalgia and dental barotrauma. Participants who reported at least one barodontalgia during a dive were prompted to answer a series of questions describing the incident. Part three investigated the relationship of the diver with his/her dentist. The questionnaire was pilot tested on a group of five divers (one dentist and four divers without specific knowledge concerning dentistry) to evaluate the format and content of questions and to improve it.
Statistical Analysis
The sample size was calculated using Epi-info™ software version 7.2.2.6 (CDC) assuming 140,000 divers were registered by the FFESSM, a 95% confidence level, a 5% margin of error, and approximatively 20% of barodontalgia among recreational divers. 15,25,27 The minimum estimated sample size was 245 divers.
The data were collected on Microsoft® Excel (Microsoft Corporation) and analyzed using RStudio® (RStudio Inc.) version 1.1.456. Data were described as numbers and percentages for categorical variables, and as means ± SD and range for continuous variables. Univariate analyses of categorical variables were performed with Chi-squared tests or Fisher’s exact tests when the expected frequencies were less than 5. For continuous variables, Mann-Whitney U-tests were performed due to the non-normal distribution (analyzed by Shapiro-Wilk test). The statistical significance was set at P < 0.05.
RESULTS
A total of 684 scuba divers, 447 men (65.4%) and 237 women (34.6%), with an average age of 48 ± 12 yr (range, 18–78 yr) participated in the study. They were registered in diving centers of 278 different French cities. They had an average dive experience of 17 ± 12 yr (range, 1–60 yr) and 84.5% of them had completed more than 80 dives. Most respondents (55.0%) were instructor-level divers ( Table I ).
At least one barodontalgia was reported by 18.7% of respondents. A total of 521 barodontalgia were reported: 12.0% and 2.9% of respondents had experienced at least 2 and 10 barodontalgia during dives, respectively. The occurrence of at least one barodontalgia was not significantly different according to the gender (χ2 = 0.80, df = 1, P = 0.37), the age (W = 36,124, P = 0.79), the years of diving (W = 30,611, P = 0.06), nor the diving qualification (χ2 = 5.25, df = 3, P = 0.15) ( Table II ).
Among divers who declared barodontalgia, 41.9% reported a dental pain during the ascent, 40.5% during the descent and 13.7% during the exploration phase. Most barodontalgia (73.4%) began in shallow water (20 m or less). The most affected teeth as identified by respondents were the posterior (81.2%) and upper teeth (55.2%). The barodontalgia concerned mainly teeth with dental filling (50.0%) ( Table III ).
The barodontalgia had several consequences: 21.9% of affected divers stopped their dive and 75.0% visited a dental clinic. Most of affected divers did not write the barodontalgia incident in his/her dive log, only 7.8% wrote them systematically and 13.3% wrote only severe pain. Among the 80 divers who declared pain in their upper teeth, 35.0% reported sinusitis associated with the barodontalgia. Among all respondents, 10.7% had experienced at least one jaw pain during a dive.
At least one dental barotrauma was reported by 10.1% of respondents, including loss or fracture of a dental filling (4.2%), dislodgement of a crown or bridge (2.3%), tooth fracture (2.0%) and a combination of these problems (1.6%). Most of the affected divers did not write the dental barotrauma incident in their dive log, only 5.8% wrote them systematically and 13.0% wrote only severe barotrauma. The occurrence of dental barotrauma was significantly higher among men (12.3%) than women (5.9%) (χ2 = 6.99, df = 1, P = 0.008) and increased significantly with age (W = 15,638, P = 0.0003), years of diving (W = 13,746, P < 0.0001) and diving qualification (Fisher’s exact test, df = 3, P = 0.04).
Regarding the relationship between divers and their dentists, 87.3% informed their dentist of their diving practice. Among respondents, 55.0% made one dental visit per year, 26.9% made less than one and 18.1% made more than one. Regarding divers who reported at least one dental visit per year in comparison to divers who reported less than one dental visit per year, no significant difference of occurrences of barodontalgia (19.6% vs. 16.3%, χ2 = 0.96, df = 1, P = 0.33) nor of dental barotrauma (11.0% vs. 7.6%, χ2 = 1.70, df = 1, P = 0.19) was found. Finally, 64.5% of divers thought that it was necessary to consult a dentist if a dental pain occurred during a dive, but 32.3% declared that a dental visit was required only for severe or persistent pain, and 3.2% thought it was not necessary to consult a dentist if a dental pain occurred during a dive.
DISCUSSION
The occurrence of at least one incidence of barodontalgia was reported by 18.7% among French civilian scuba divers in this study. This result appeared similar to the other studies performed among recreational divers, 15,25,27 but higher than studies performed among professional divers. 9,33 This study is in accordance with the review study of Nakdimon and Zadik 21 which showed that barodontalgia was experienced significantly more by civilian than military scuba divers. This is likely due to regular dental follow-ups in French military divers and the emphasis on maintaining good oral health among these professionals. 10 By comparison, French people have varied dental access and therefore varied visiting frequency dependent on this. 4,23 For example, only 15.9% of French people make a dental appointment despite having an oral problem like gingiva bleeding, 5 and only 33.8% of French athletes, like handball players, visit a dental clinic after an orofacial injury. 12
In accordance with other studies, 25,33 barodontalgia affected mainly posterior teeth. This can be explained by the fact that molars are generally most susceptible to dental caries and are most frequently filled. 6 Dental caries and faulty fillings are two pre-existing dental pathologies which can induce barodontalgia. 31 In addition, nondental-induced barodontalgia caused by sinus barotrauma may explain several pains of upper molars. 16 In this study, like in similar studies, 1,15,26 nearly one third of divers who declared pain in upper teeth reported sinusitis associated with the barodontalgia.
In this study, barodontalgia began mainly in shallow water (10 m or less). During a dive, the first 10 m present the greatest variation of the absolute pressure which is multiplied by two. Very few studies have reported the depth at which barodontalgia occurs and they did not describe depth below 18 m. 2
In this study, barodontalgia occurred both during ascent (41.9%) and descent (40.5%). In other studies, it appeared mainly during descent. 9,25 Zadik suggests the occurrence of pain on ascent or descent is a function of the underlying pathology, with pain on the ascent related to vital pulp disease like reversible and irreversible pulpitis, while pain on the descent is related to pulp necrosis or facial barotrauma like middle ear or sinus barotrauma. Pain related to periapical disease can appear both during ascent and descent. 31
In this study, 73.1% of divers surveyed consult a dentist at least once a year. In comparison, 88.5% of French military divers consulted a dentist at least once a year. 10 Among French military divers, barodontalgia occurrence was significantly higher in divers who have an examination less than once per year (14.5%) in comparison to divers who usually have a dental examination once a year or more (6.3%). 9 Among occupational divers, a relationship between the frequency of preventative dental visits and tooth pain while diving was shown. 22 However, in contrast, in this study the frequency of dental visits did not significantly affect the occurrence of barodontalgia, and it was higher among divers who consulted their dentist at least once per year in comparison with divers who visited their dentist less than once per year. It may be these divers visited their dentist more frequently because of a history of dental pathology which was later revealed during a dive. Among divers who reported one incidence of barodontalgia in this study, 64.1% declared a second incidence of barodontalgia despite 75.0% of them visiting a dental clinic after the occurrence of barodontalgia. So, the level of specialist training of dentists in diving medicine may be an important factor to prevent dental symptoms during a dive. 9
Regarding dental barotrauma, it occurred at least once in 10.1% of divers in this study. It was experienced by 5.3% and 6.3% of French military divers 10 and Swiss professional divers, 33 respectively. In all of these studies, dental barotrauma occurred mainly in teeth that had undergone dental fillings. The increase in pressure during diving can affect the integrity of dental fillings, generating fissures 8 and porosities with loss of seals at the tooth/filling interface. 20
The main limitation of this study was the retrospective design of the study via the use of a self-administered questionnaire, which made the study prone to the participants’ memories and possible subjectivity. In theory, all incidents occurring during a dive should be written by divers in their dive logs. But nearly 80% of them reported that they did not write the occurrence of barodontalgia or dental barotrauma in their dive logs. So, it is possible that minor pains and barotrauma were forgotten or ignored. Moreover, no clinical examination was conducted in this study and divers reported self-diagnosed. However, a self-administered questionnaire is the preferred method of the vast majority of barodontalgia studies, with the exception of a few studies which included only 8 divers 8 and 27 aircrews. 28 A major strength of the study was the diversity of a wide national sample which included 684 scuba divers (nearly three times more respondents than the minimum estimated sample size), men and women aged 18 to 78 yr. However, this sample includes only 0.5% of FFESSM divers (684/140,000) and includes a high proportion of respondents with an instructor level (55.0%) probably due to the greater interest of the instructors on this issue. This study among French civilian divers completes the existing pool of literature regarding barodontalgia among French military divers 9,10 and among French military and civilian pilots and aircrew members. 18
The occurrence of barodontalgia and dental barotrauma among scuba divers is high, notably among civilian and recreational divers. Dentists should, therefore, be aware of these dental symptoms and use preventive measures among divers in order to reduce their frequency and severity. They must treat tooth decay and damaged fillings before a dive. Information must be provided to divers concerning the significance of routine dental checkups and screening so as to avoid barodontalgia and dental barotrauma.
Contributor Notes
