Impact of inhalation therapy on the incidence of carious lesions in patients with asthma and COPD

Abstract Objective: The aim of this study was to investigate the incidence of carious lesions, the amount of salivary flow rate and pH value in patients with asthma and chronic obstructive pulmonary diseases (COPD), using inhalation therapy. The obtained results were compared with the results of adult healthy subjects, forming a control group. Material and Methods: The study included 80 participants aging between 18 and 65 years. The experimental group (EG) was comprised of 40 participants, previously diagnosed with asthma or COPD undergoing inhalation therapy for more than five years. The control group (CG), comprised of 40 participants, mirrored the same age and gender status of the EG. Dental status was determined by decayed, missing, and filled teeth (DMFT index). Quantity and pH value of saliva were determined in the laboratory. Results: In the EG, the mean value of the salivary flow rate and pH value were statistically significantly lower than in the CG (p<0.001). Patients in the EG had a higher value of DMFT index when compared with the CG, although the difference was not statistically significant (p=0.199). Mean number of decayed teeth, as well as missing teeth, in the EG was statistically significantly higher than in the CG (p<0.001). Mean number of filled teeth in the EG was statistically significantly lower than in the CG (p<0.001). Conclusion: It was found that patients undergoing inhalation therapy face increasing risk of dental caries due to the lower salivary flow rate and pH value along with the inhalation therapy. They should receive intensive preventive care, including oral hygiene instruction and dietary advice.


Introduction
Dental caries represents a multifactorial disease and it is one of the most prevalent chronic diseases worldwide. Caries lesion forms through a complex and fermentable carbohydrates on the tooth surface.
The occurrence of carious lesions is an outcome of the disturbed balance between dietetic-bacterial factors and host factors, and the usage of different drugs 11 . Based on studies 3,6,13,15,24 , patients undergoing inhalation therapy are subjected to higher risk of dental caries, due to the reduced saliva secretion, decreased pH value, enlarged number of cariogenic bacteria caused by inappropriate oral hygiene, and the usage of inhaling medicaments with dry powder. These changes could be related to basic diseases or to the prescribed therapy.
Asthma and chronic obstructive pulmonary diseases (COPD) are predominantly chronic respiratory diseases, the prevalence of which grows in many countries as well as in Serbia (Europe). According to Global Initiative for Asthma 8 , it is estimated that around 400 million people suffer from asthma. The prevalence of asthma in Serbia is 4-5%, and in 2011, asthma prevalence on the territory of Serbia was 6.8% 17 . According to Global Initiative for Obstructive Lung Disease, it is estimate that COPD is a leading cause of morbidity and mortality wordlwide 26 . The COPD prevalence has increased from 7% to 14% in the past nine years 28  The major proportion of the inhaled drug is retained in the oral cavity and oropharynx and it may interfere in the normal physiology of oral tissues 9 . The usage of the inhaled beta-2 agonist in combination with glucocorticoids in asthmatic patients cause the 18 and they can reduce the effect of saliva in the aid of protection against caries 21 . pH value is lower, there is increased food retention, an acidic environment is encouraged and persists longer 9 . Prolonged use of beta-2 agonists is associated with the increased frequency of caries, which could be explained through the basic effect of beta-2 agonists that are connected to the present beta-2 receptors in the parotid and other salivary glands 4 .
The increased susceptibility to dental caries can also be due to the frequent use of dry powder inhaler containing fermentable carbohydrates. The most common is lactose monohydrate, and although it is one of the least cariogenic sugars, it can still lead to an increased dental caries risk 25

Clinical caries examination
Dental examination was carried out by three dentists. Three examiners performed data collection, one responsible for the questioner, another for saliva value), and the last one for the dental diagnosis.
The examiners were blinded to the subject's group assignment. Dental caries diagnosis was performed according to WHO criteria 29 , and DMFT index for permanent teeth (number of decayed, missing, and Checkup was made under standard dental control using a dental mirror and dental probes with artificial illumination. A clinical study contained a dental checkup comprising participants' health status of hard dental tissues and the presence of manifest carious lesions. Radiograph was not included in the examination.

Salivary and pH analyses
Laboratory investigation comprised registering the pH value. Before the saliva sample completion, the participants of both groups were informed about the measures that have to be adhered to, i.e., that before the completion they should refrain from alcohol use (for 12 hours), from substantial meals (for 60 minutes) as well as from richly sweet, caffeine, or sour drinks and foods. The participants were also informed that they should not have any dental checkups or

Results
In the present study, 80 patients were enrolled, 40 in EG and 40 in CG. The obtained results are shown in between EG and CG regarding gender (p=1.000) and age (p=1.000). Prior the beginning of the study, more than 30% of potential participants were excluded because of some reasons.
Regarding the type of disease, 70% of patients were suffering from asthma and 30% were suffering from COPD in the EG. Most of the participants in both groups were allocated into the moderate type of treatment, most of the participants in both groups had been using inhalation therapy for 5-10 years about regularity of undergoing therapy was positively The EG participants in their treatment of asthma or COPD used a combination of two or more medicines.
Frequency of medicine application of the participants in the EG who used inhalation therapy regularly was two times/day. We found out that the EG participants used   Table 2-Descriptive data about the type of disease, length of treatment, and regularity of therapy (%) Impact of inhalation therapy on the incidence of carious lesions in patients with asthma and COPD as well as the one in the mean salivary pH value (p<0.001), which was 6.63 in the EG and 7.23 in the CG ( Table 4).
The mean value of DMFT index in the EG was 21.2, while in the CG this value was lower, i.e., 19.4, but no the groups (p=0.199). However, we found statistically components: mean number of decayed teeth in the EG was 3.68, while in the CG this value was lower, 1.40 (p<0.001); mean number of missing teeth in the EG was 12.3, while in the CG this number was CG this result was higher, 11.6 (p<0.001) ( Table 5).
Based on the results of DMFT index (p=0.177) and caries lesion (p=0.153) regarding the severity degree was observed. Also bsed on the results of DMFT index (p=0.541) and caries lesion (p=0.689) concerning difference was found either.

EG CG p value
The most consumed beverag -water -sparkling water, fruit juice, sport beverage -milk, yoghurt plays an important role in its preservation 24 . The pH value of non-stimulated saliva in this study was lower in the EG than in the CG (p<0.001), which corroborates the results of other authors 6,18,23 . Although salivary pH was lower in the experimental group, it was not below the "critical pH" (5.5), which resulted in the enamel demineralisation 25 .
Previous studies have a common statement that patients who suffer from asthma or COPD and who are undergoing inhalation therapy have considerably reduced saliva secretion as well as a lower salivary pH value 6,18 , and this could be a determinant factor causing dental caries. However, the question whether these patients have a higher prevalence of caries if opinions and contradicted results as well as the question whether the severity and length of the disease correlates with a higher incidence of caries lesions. A group of authors think that there is a higher prevalence of caries in patients undergoing inhalation therapy 1,3,21,22 , which is in accordance with the results of this study. However, another group of authors 16,18 found that patients with asthma have similar dental caries prevalence when compared with the control group, suggesting that this might be due to the fact that this particular group of patients had proper access Impact of inhalation therapy on the incidence of carious lesions in patients with asthma and COPD

Conclusion
We found that patients undergoing inhalation therapy face increasing risk of dental caries due to a the inhalation therapy. In order to stop the disease progression in the hard dental tissue of the mouth cavity, it is necessary to apply adequate preventive measures and positively motivate their continuous application in this caries-risk population.
A better mutual collaboration among dentists, general practitioners, and pulmonary specialists would contribute to improve general oral and dental health in these patients.