Effect of low level laser stimulation on salivary gland function in diabetic patients with hyposalivation

Abstract

Saliva plays several functions and the most important roles among of those are the lubrication and the protection by defensive proteins. Salivary gland hypofunction showed a high prevalence in patient with diabetes. Previous studies indicated that protein mucin 5B concentration, which is important to lubrication, tended to decrease in hyposalivation patients and a decrease in histatin 5 was found in disease with fungal infection. The several previous studies indicated that low level laser therapy (LLLT) can stimulate salivary gland function with an increase in salivary flow rate in systemic disease patients with dry mouth complication. Therefore, LLLT may be applied as the treatment choice for patients with dry mouth symptom. This study aimed to investigate the effect of low-level laser stimulation on salivary gland function in diabetic patients with hyposalivation. The assessment of salivary flow rates, mucin 5B (MUC5B), mucin 7 (MUC7), histatin 5 concentrations, and questionnaires were performed. A total of twelve diabetic patients under criteria set in this study at Bangkok Hospital were participated on a voluntary basis. A low power laser was used to stimulate major salivary glands with an irradiation time of 40 s on 6 occasions (3 times in 2 consecutive weeks). Questionnaire related to dry mouth symptoms were given. Salivary flow rates and questionnaire were assessed as well as MUC7, MUC5B, and histatin 5 protein concentration in saliva at the 1st visit, 6th visit, and 6th week follow-up visit. The unstimulated salivary flow rate and MUC5B concentration at the 6th week follow-up visit were significantly increased compare with at the 1st visit. By contrast, the concentration of histatin 5 exhibited a significant decrease at the 6th week follow-up visit compare with at the 1st visit . The mean dry mouth score revealed a significant decrease regarding to dry mouth symptoms at the 6th visit and 6th week follow-up visit compared with at the 1st visit. The correlation between overall dry mouth score and flow rate showed the strongest positive correlation at the 6th visit. There were no significant differences found on stimulated salivary flow rate and MUC7 concentration. Our results indicate a beneficial effect of LLLT on diabetic patients in increasing salivary flow rate and maintaining oral lubrication.