Authors: Mitsuhiro Asami, Yasuyuki Kimura, Miho Takenoshita, Risa Tominaga, Chizuko Maeda, Chihiro Takao, Motoko Watanabe, Trang Thi Huyen Tu, Takahiko Nagamine, Akira Toyofuku
Categories: Original Article, And filled teeth (DMFT), Decayed, Missing, Oral psychosomatic disorders, Psychiatric disorders
Source: Journal of Dental Sciences
Background/ Dentists sometimes struggle with treating patients with unexplained symptoms, known as oral psychosomatic disorders, that do not improve with conventional treatment. Oral psychosomatic disorders do not fit the definition of psychosomatic diseases in internal medicine. To ensure appropriate dental treatment, it is important for general dentists to distinguish between oral psychosomatic disorders and psychosomatic diseases. However, relevant evaluation methods have not yet been developed. The DMFT index is widely used as an indicator of the caries status. The purpose of this study was to compare the DMFT index scores of patients with oral psychosomatic.
The DMFT scores of 2202 patients with oral psychosomatic disorders, 145 psychiatric inpatients, and 3940 general dental patients were statistically compared. The DMFT of patients with oral psychosomatic disorders was further compared based on the presence or absence of psychiatric history and disease.
The median DMFT scores of oral psychosomatic disorder patients, psychiatric inpatients, and general dental patients were 16, 22, and 10, respectively, showing a significant difference. No significant differences were found in the DMFT scores based on the presence or absence of psychiatric history in oral psychosomatic disorder patients.
The intraoral environment of patients with oral psychosomatic disorders was worse than that of general dental patients but better than that of psychiatric inpatients. General dentists could suspect psychiatric and oral psychosomatic disorders based on the state of patients’ oral environment.
Keywords: Decayed, Missing, And filled teeth (DMFT), Oral psychosomatic disorders, Psychiatric disorders
Dentists sometimes encounter patients with unexplained symptoms that do not improve with conventional dental treatments. Such complaints include chronic pain or discomfort in the oral cavity, such as foreign body sensation and occlusal discomfort. However, these are rare, and the patients often do not receive adequate treatment. Complaints of “pain that won't go away” or “bite that doesn't fit” have been conventionally referred to as “oral psychosomatic disorders.” These disorders do not necessarily fit the definition of psychosomatic diseases in internal medicine.^1^ It has been reported that approximately 50% of patients with oral psychosomatic disorders have comorbid psychosomatic diseases, such as depression and anxiety.^2^ Therefore, it is difficult for general practitioner (GP) dentists to distinguish between oral psychosomatic disorders and psychiatric diseases.
In recent years, due to a reduction in psychiatric beds, patients who would have been hospitalized in the past are now receiving medical treatment while living in society. Such patients also visit dental clinics with dental complaints, and situations that cannot be resolved with standard responses are becoming increasingly common. Regardless of whether there is a coexisting psychiatric disease, such patients appear to GPs as “patients who cannot be treated effectively.” It is difficult for dentists to detect a patient's mental state until the patient complains of deterioration. For appropriate dental care, it is important to quickly recognize latent mental symptoms in patients who visit dental clinics; however, no method has been established yet.
The oral condition in patients with oral psychosomatic disorders but “no organic abnormalities” is not necessarily bad. However, it is reported that patients with psychosomatic disorders have a poor oral environment. According to Kenny et al.,^3^ patients with serious mental disorders are more likely to lose all their teeth and have a significantly poorer oral environment than that of the general population. As noted above, oral psychosomatic disorders may differ from psychiatric diseases, even in terms of patients’ oral environment. However, no studies comparing the oral environment of the two groups have been reported.
The DMFT index was developed by Klein in 1938 to evaluate caries.^4^ This index is widely used as an indicator of the caries status in a region or population.^5^ It includes the total number of decayed teeth (DT), missing teeth (MT), and filled teeth (FT). Scores for this index range from 0 to 28, with higher scores indicating more caries experience and poorer dental health of the patient.^6^ In this study, we focused on the DMFT index, which can be easily performed during routine oral examinations. This study aimed to clarify the characteristics of the oral environment of patients with oral psychosomatic disorder. We compared the DMFT index of the following three patients with oral psychosomatic disorders (oral psychosomatic disorder patients), those with oral psychosomatic disorders who were admitted to a psychiatric hospital (psychiatric inpatients), and those visiting a GP dentist.
Patients from three medical institutions were included in this study.
Oral psychosomatic disorder patients were selected from among those diagnosed with psychosomatic dental disease at the Psychosomatic dentistry clinic, Tokyo Medical and Dental University (TMDU) Dental Hospital between April 2015 and February 2021. In total, 2272 patient documents were retrospectively screened.
Psychiatric inpatients admitted to a single-department psychiatric hospital in Tokyo with a dental-care unit were screened. A total of 145 patients, excluding 42 who met the exclusion criteria, were selected from among all patients who visited the dental room on the weekly survey day between September 2020 and February 2021.
General dental patients were selected from among those who visited a dental clinic for the first time between April 2015 and February 2021. This general dental clinic was located near the TMDU Hospital. The total number of patients was 3940, excluding one patient who met the exclusion criteria.
Patients under 18 years of age, patients who refused to participate in the study, and patients with incomplete medical record entries for the oral examination were excluded from the study subjects.
Informed consent was obtained through an opt-out procedure. Subjects was provided with an opportunity to refuse participation in the study by displaying a poster in each medical institution. The study was approved by the Ethics Committee of the School of Dentistry of TMDU (permit D2021-031).
The age, sex, and history of psychiatric disorders of the patients were retrospectively collected using the medical record system at each institution. Data on the DMFT, DT, MT, and FT scores were obtained for 28 teeth, excluding the third molars, from medical records, intraoral photographs, and panoramic radiographs. The psychiatric disorders prevalence among patients with oral psychosomatic disorders was surveyed by the medical records in their first visit.
The participants were further classified into three groups according to 18–44 years old, 45–64 years old, and 65 years or older.
Regarding the subjects' psychiatric history, psychosomatic diseases were classified as schizophrenia, dementia, depression, bipolar disorder, anxiety disorder, insomnia, and others, and their prevalence rates were compared among the three institutions. Patients with oral psychosomatic disorders were divided into two groups based on whether they had a history of psychiatric disorders, and the patients’ DMFT score, DT, MT, and FT were compared. In addition, oral psychosomatic disorders were classified into the following four major categories^7^: burning mouth syndrome (BMS), oral cenesthopathy (OC), atypical odontalgia (AO), and phantom bite syndrome (PBS), and were compared and examined in the same manner.
The age and DMFT, DT, MT, and FT scores of the subjects were non-normally distributed according to the Shapiro-Wilk test, so they were expressed as medians (interquartile range). The Mann-Whitney U test and Kruskal-Wallis test were used to analyze the DMFT index, DT, MT, and FT of the patients. Statistical analysis was performed using IBM SPSS Statistics (version 25.0; IBM Corporation, Armonk, NY, USA), with a two-sided P < 0.05 indicating statistical significance.
The median (interquartile range) ages of oral psychosomatic disorder patients, psychiatric inpatients, and general dental patients were 63 (20), 70 (25), and 33 (15) years, respectively. The proportions of women in the three groups were 82.6%, 58.6%, and 43.1%, respectively.
The DMFT index score was significantly different among the patient groups (P < 0.001) (Fig. 1). In particular, psychiatric inpatients had significantly higher DMFT scores than those of patients with oral psychosomatic disorders. The number of general dental patients was significantly smaller than that of patients with oral psychosomatic disorders (P < 0.001). The FT score was significantly different among the three groups, with oral psychosomatic disorder patients having the greatest FT score. The DT score showed no significant differences among the three groups. With respect to age, in the 45-64-year age group, the DMFT and DT scores of psychiatric inpatients were significantly higher than those of oral psychosomatic and general dental patients (P < 0.001) (Fig. 2). The MT score was significantly higher and the FT score was significantly lower in psychiatric inpatients than in the other two groups. The DT score showed no significant difference among the patient groups. The DMFT score of patients >65 years was greater for the psychiatric inpatient group, followed by the oral psychosomatic group, with the lowest score for the general dental patient group, with significant differences among the three. (P < 0.001). In the 18–44 years age group, there were no significant differences in the DMFT, DT, MT, or FT scores among the three patient groups.
Figure 1 DMFT, DT, MT, and FT scores at the three institutions. The DMFT, MT, and FT scores were significantly different among the three institutions (P < 0.001). The DMFT score of psychiatric inpatients was significantly higher, and that of patients in a general dental clinic was significantly lower than that of patients with oral psychosomatic disorders.
Figure 2 Comparison of DMFT, DT, MT, and FT scores by age in the three institutions. In the 45–64 years age group, the DMFT, DT, and MT scores of psychiatric inpatients were significantly higher than those of patients with oral psychosomatic disorders and patients in a general dental clinic (P < 0.001). In the >65 years age group, psychiatric inpatients had significantly higher MT and lower FT scores than those of the other two groups. On the other hand, these scores for the 18–44 years age group were not significantly different among the three institutions.
The prevalence rates of psychiatric disorders among oral psychosomatic disorder patients, psychiatric inpatients, and general dental patients were 48%, 100%, and 0.9%, respectively (Fig. 3). In the oral psychosomatic disorder group, 52% patients had no history of psychiatric diseases, followed by 17% (n = 364) with depression, 7% (n = 160) with anxiety disorder, 4% (n = 92) with insomnia, 2% (n = 46) with bipolar disorder, and 1% (n = 31) with schizophrenia. The prevalence of psychosomatic diseases in psychiatric inpatients was as 39% patients (n = 56) had schizophrenia, 26% (n = 38) had dementia, 7% (n = 10) had depression, and 3% (n = 4) had bipolar disorder. In the general dental patient group, 0.6% (n = 24) had depression and 0.2% (n = 8) had insomnia.
Figure 3 Prevalence of psychiatric diseases in the three institutions. The prevalence of psychiatric disorders among patients with oral psychosomatic disorders, inpatients, and patients in a general dental clinic was 48%, 100%, and 0.9%, respectively. Schizophrenia was the most common disorder among inpatients with psychiatric disorders, and depression was the most common psychiatric disorder among patients with oral psychosomatic disorders.
Focusing on depression, the median DMFT scores of oral psychosomatic disorder patients, psychiatric inpatients, and general dental patients were 16 (8), 24.5 (7), and 10.5 (16), respectively, with significant differences among the three institutions (P < 0.001).
Focusing on oral psychosomatic disorders, we compared the DMFT, DT, MT, and FT scores between oral psychosomatic disorder patients with a psychiatric history (n = 1053, 47.8%) and those without (n = 1047, 47.5%). No significant differences between patients with and without a psychiatric history were found (Fig. 4). The DMFT scores of oral psychosomatic disorder patients were compared for each disease (Fig. 5). DMFT scores of patients with BMS (n = 1223, 56%), OC (n = 452, 21%), AO (n = 382, 17%), and PBS (n = 118, 5%) were 16 (9), 16 (8), 14 (8), and 17.5 (9), respectively. The DMFT was significantly lower (P < 0.001) for patients with AO than for patients with BMS, OC, and BPS. The DT score of patients with BMS, OC, AO, and PBS was 1 (2), 1 (2), 1 (2), and 2 (4), respectively. The DT score of patients with PBS was significantly higher (P < 0.001) than of patients with BMS, OC, and AO. Patients were often in the process of prosthetic rehabilitation with temporary crowns during the initial examination. Temporary crowns indicated the DT score. The mean DT score for patients with PBS was 2.69, of which 1.72 indicated temporary crowns.
Figure 4 DMFT, DT, MT, and FT scores in oral psychosomatic disorder patients with and without psychiatric history. There were no significant differences in the DMFT, DT, MT, or FT scores between patients with and without a psychiatric history.
Figure 5 Comparison of the DMFT, DT, MT, and FT scores by oral psychosomatic disorder. The DMFT score was significantly lower (P < 0.001) for patients with atypical odontalgia than for those with burning mouth syndrome, oral cenesthopathy, and phantom bite syndrome. The DT score of patients with the phantom bite syndrome was significantly higher (P < 0.001) than that of patients with burning mouth syndrome, oral cenesthopathy, and atypical odontalgia.
The main findings of this study are as 1) the intraoral environment of patients with oral psychosomatic disorders was worse than that of general dental patients but better than that of psychiatric inpatients; 2) there was no significant difference in the DMFT score of oral psychosomatic disorder patients with or without a history of psychiatry.
Our findings showed that the DMFT score of oral psychosomatic disorder patients was statistically less than that of psychiatric inpatients (Fig. 1). Psychiatric inpatients have been reported to have decreased salivation due to side effects of psychiatric medications,^8^ increased risk of dental caries,^9^^,^^10^ and difficulty with self-care due to motor disturbances, such as tremors.^11^^,^^12^ Meanwhile, the DMFT score of oral psychosomatic disorder patients was greater than that of general dental patients. Since oral psychosomatic disorders involve complaints of chronic pain in the oral cavity, foreign body sensations, or abnormal occlusal sensations,^13^ these patients may receive more dental treatment. The MT score tends to increase with each additional year of age.^14^ To eliminate confounding by age, the three groups were compared by age group (Fig. 2). The same trend as above was found for patients >45 years, while the DMFT score of patients <45 years was not significantly different among the three groups.
The prevalence of psychiatric disorders among patients with oral psychosomatic disorders was 48% (Fig. 3). Depression is the most common psychiatric disorder worldwide. In contrast, schizophrenia is the most common disease among inpatients with psychiatric disorders. Thus, oral psychosomatic disorders and inpatients had different psychiatric histories. There was no significant difference in the DMFT score of oral psychosomatic disorder patients with or without a history of psychiatric disorders (Fig. 4). Oral psychosomatic disorders with comorbid psychiatric disorders affected outpatients with depression and anxiety disorders, who were presumed to be highly independent and maintained a good oral environment. Focusing on depression, the DMFT scores of oral psychosomatic disorder patient and psychiatric inpatients were 16 and 24.5, respectively, with significant differences. The reason for the higher DMFT score in psychiatric inpatients with depression may be because depression among outpatients is clearly different from that among inpatients, and psychiatric inpatients have been reported to have impaired motor function,^15^^,^^16^ which can lead to decreased self-care.^6^^,^^17^ In future, we plan to examine the severity of psychosomatic diseases and further investigate the relationship between the severity of psychosomatic diseases and intraoral environment. Psychiatric inpatients had high MT and low FT scores; therefore, it was assumed that they received less dental treatment and had more missing teeth.
A comparison of DMFT scores in oral psychosomatic disorder patients according to disease showed that the DMFT score was significantly lower in patients with AO than for patients with BMS, OC, and PBS (Fig. 5). AO is characterized by persistent pain affecting the tooth or alveoli after a dental procedure or tooth extraction. AO is difficult to diagnose because there is often no significant clinical or radiographic finding.^18^ In addition, owing to the difficulty in diagnosing cases of AO in the general dental outpatient setting, dentists may have treated them discreetly, leading to a lower DMFT score among patients with AO than in those with other complaints. In addition, the DT score was significantly higher in patients with PBS than in those with BMS, OC, and AO. PBS is characterized by an abnormal sense of occlusion that does not improve with normal dental treatment and a variety of associated systemic complaints. These patients are at a risk of overtreatment due to their persistent complaint of abnormal occlusion and strong desire for dental procedures.^19^^,^^20^ In fact, our findings showed that patients with PBS were often in the process of prosthetic rehabilitation with temporary crowns, and because temporary crowns were counted in the DT score, we speculated that the DT and DMFT scores might have been higher.
Few previous studies have examined the intraoral environment of patients with oral psychosomatic disorders. No study has ever compared the intraoral environment of psychiatric inpatients and general dental patients using the DMFT, DT, MT, and FT scores. However, this study has several limitations. First, the study sample was not a random sample of all psychiatric inpatients, general dental patients, or oral psychosomatic disorder patients in Japan, and therefore the study results may be generalizable. Second, the DT score may have been underestimated in cases of undetected caries at proximal surfaces during examination in the outpatient dental room of the psychiatric hospital. In this study, dentists who are familiar with psychiatric disorders carefully check the oral cavity. However, unlike the other two groups who visit the hospital for oral treatment and examination purposes, radiography is optional in psychiatric inpatients. The DT of psychiatric patients was the largest among the three groups, and even if it were slightly higher, it would have very little effect on the conclusion. Third, with the exception of age and sex, the chief complaint, route of presentation, onset of illness, duration of illness, treatment outcome, and number of medications administered were not considered due to a lack of available information. Further studies are needed to examine the actual oral condition of patients with oral psychosomatic disorders taking these factors into account.
This study showed that the intraoral environment of patients with oral psychosomatic disorder was worse than that of general dental patients but better than that of psychiatric inpatients. Psychiatric inpatients were characterized by many missing teeth, few treated teeth, and a deteriorated intraoral environment. Since the DMFT index goes up when looking at the oral environment of psychiatric disorders and oral psychosomatic disorders, we thought it necessary to consider that patients with significant oral conditions may have psychiatric disorders. Psychiatric disorders and oral psychosomatic diseases are not distinguishable by intraoral examination. It is difficult for general dentists to distinguish between psychiatric disorders and oral psychosomatic disorders from a medical interview alone. The results of this study suggest a method for general dentists to assist in both screening by focusing on DMFT in addition to medical interviews. We believe that these results will contribute to the early access to appropriate medical care for oral psychosomatic patients. GPs should therefore pay close attention to patients’ intraoral conditions to uncover them.
The authors have no conflicts of interest relevant to this article.
The present study was supported by the Japan Society for the Promotion of Science KAKENHI(Grant Number JP22K10141).