Effects of Photobiomodulation in Children With Down Syndrome and Possible Sleep Bruxism

Effects of Photobiomodulation in Children With Down Syndrome and Possible Sleep Bruxism: Protocol For A Randomized, Controlled, Blind, Clinical Trial

Hypotonia, particularly of the masticatory and oropharyngeal muscles, is one of the main characteristics of Down syndrome, resulting in impaired speech, chewing and swallowing. Moreover, the complete or partial obstruction of the airways during sleep may occur due to hypotonia of the tongue, leading to snoring and sleep disorders, such as obstructive apnea and sleep bruxism. Objectives: Analyze salivary levels of dopamine and cortisol and muscle activity before and after treatment with low-level laser therapy administered to acupoints in children with Down syndrome. Methods: A randomized, controlled, clinical trial will be conducted. Individuals four to 17 years of age with a diagnosis of Down syndrome and possible sleep bruxism will be screened at the Integrated Health Clinic of Nove de Julho University. We will evaluate orofacial dysfunction (NOT-S questionnaire), facial sensitivity, activity of the masticatory and trapezius muscles (electromyography), head posture as well as salivary cortisol and dopamine. After the evaluations, the participants will be randomized into two groups: Grupo 1 - treatment with low-level laser therapy at a wavelength of 808 nm; Group 2 - sham treatment (simulated laser therapy). Treatment will be conducted twice per week for a total of 12 sessions. The data will be tabulated and treated using GraphPad Prism version 7.0. The Kolmogorov-Smirnov test will be used to determine the normality of the data. Variables that fit the Gaussian curve will be expressed as mean and standard deviation. The t-test will be used for comparisons between the groups, with the significance level set to 5% (p <0.05).

Sessions will be held twice a week for six weeks (total: 12 session). A potentiometer will be used to measure the mean power of the equipment and therapeutic dose, ensuring safety to the participant and operator. Laser will be administered at a wavelength of 786.94 nm using an energy density of 2 J/cm², intensity of 1.675 mW/cm² and power of 70 mW (0.070 W) for 20 seconds per point. The point application method will be used with a conventional tip in contact with the skin (spot area: 0.04 cm²) following the protocol suggested by Venezian et al.59 and Carvalho et al.60.

Sessions will be held twice a week for six weeks (total: 12 session). During sham treatment the device will emit a guide light and sound, but no energy.

Cortisol will be measured from saliva samples. Non-stimulated saliva will be collected in the morning or afternoon with the participant fasting or at least two hours since the last meal. The participant will be seated comfortably in a well-ventilated environment with the head inclined slightly forward without swallowing to allow saliva to accumulate on the floor of the mouth. The saliva will be expelled for a period of five minutes into a funnel coupled to previously weighed tube partially immersed in crushed ice. Salivary flow will be calculated as mL/min. Two mL of saliva will be collected. The samples will be transported under refrigeration to the Cellular Culture and Research Lab of Nove de Julho University (Vergueiro campus) for centrifugation (5000 g, 5 min, 4°C) and storage at -80°C. The material will be discarded after use.

Dopamine will be measured from saliva samples. Non-stimulated saliva will be collected in the morning or afternoon with the participant fasting or at least two hours since the last meal. The participant will be seated comfortably in a well-ventilated environment with the head inclined slightly forward without swallowing to allow saliva to accumulate on the floor of the mouth. The saliva will be expelled for a period of five minutes into a funnel coupled to previously weighed tube partially immersed in crushed ice. Salivary flow will be calculated as mL/min. Two mL of saliva will be collected. The samples will be transported under refrigeration to the Cellular Culture and Research Lab of Nove de Julho University (Vergueiro campus) for centrifugation (5000 g, 5 min, 4°C) and storage at -80°C. The material will be discarded after use.

The sensory evaluation will be performed using the Semmes-Weinstein kit (Smiles®), which contains a set of six nylon monofilaments (esthesiometry) of the same length that exert pressure on the specific site of the skin tested. Each monofilament has a specific color and diameter: green (0.05 g), blue (0.2 g), violet (2 g), red (4 g), orange (10 g) and magenta (300 g) 16. The test will be performed on dermatomes. The score ranges from seven (green monofilament) to 1 (magenta monofilament).18

The clinical (visual) assessment of head posture will be performed using a posture grid. The participant will be instructed to stand with his/her natural posture. The natural balance of the head will be used to standardize the posture of each subject, who will be instructed to look forward with the gaze on the horizon. Semi-spherical polystyrene markers measuring 1.5 cm in diameter will be attached to the skin with double-sided adhesive tape at three anatomic points: the spiny process of the seventh cervical vertebra (C7), the manubrium of the sternum (A1) and the mental protuberance (MP). Photographs will be taken of each participant in right-side view.

The following functions are addressed during the interview: (I) sensory function, (II) breathing, (III) habits, (IV) chewing and swallowing, (V) drooling and (VI) dryness of the mouth. The following functions are evaluated during the physical examination: (1) face at rest, (2) nose breathing, (3) facial expression, (4) masticatory muscle and jaw function, (5) oral motor function and (6) speech. For the evaluation of orofacial dysfunction during the clinical examination, the participants will be asked to perform tasks for each item in accordance with the illustrated manual. Each item has criteria for the respective function. A "YES" response or task the meets the criteria for compromised function will be scored 1 point, indicating dysfunction in the respective domain. A "NO" response or task that does not meet the criteria will be scored zero. The total is the sum of the points of all domains and ranges from 0 to 12, with higher scores denoting greater orofacial disfunction.

Inclusion Criteria: Children and adolescents with a diagnosis of Down syndrome Four to 17 years of age Bruxism, based on parental reports of the occurrence of grinding the teeth, incisal and/or occlusal tooth wear following the criteria of the American Academy of Sleep Medicine (AASM) and the questionnaire for the evaluation of bruxism validated by Serra Negra et al. (2014) and a systematic review performed by Manfredini et al. (2013). Exclusion Criteria: Use of muscle relaxant Temporomandibular disorder Undergoing other therapy for bruxism Other associated neurological diseases Cognitive deficit that impedes understanding the evaluations.

Salgueiro MDCC, Silva T, Motta LJ, Horliana ACRT, Goncalves MLL, Gomes AO, Pinto MM, Bortoletto CC, Altavista OM, Deana AM, Silva DFTD, Santos EM, Castelo PM, Fernandes KPS, Mesquita-Ferrari RA, Bussadori SK. Effects of Photobiomodulation in Children with Down Syndrome and Possible Sleep Bruxism: Protocol For A Randomized, Controlled, Blind, Clinical Trial: Study protocol clinical trial (SPIRIT compliant). Medicine (Baltimore). 2020 Apr;99(17):e19904. doi: 10.1097/MD.0000000000019904.