Therapeutic exercises, manual therapy, and health education program for adolescents with temporomandibular disorders: face-to-face and online multimodal rehabilitation protocol for a randomized controlled clinical trial

Abstract

Background

Multimodal rehabilitation has shown good results in adults with temporomandibular disorder (TMD), but there is still doubt regarding the protocol’s ideal format (face-to-face or online), and its effectiveness among adolescents. The purpose of this study is to describe a randomized clinical trial protocol of face-to-face and online multimodal rehabilitation, in adolescents with TMD, and to determine its effects on pain, peripheral oxygenation of the masseter muscle, and mandibular range of motion, kinesiophobia and parafunction.

Methods

A randomized, controlled clinical trial, blinded to statistical analyses, will be carried out, involving 26 adolescents, diagnosed with TMD. After randomization, the participants will be allocated into two groups: (1) telerehabilitation and (2) face-to-face treatment groups. Each group will undergo an initial assessment, followed by three treatment sessions, reassessment, and follow-up. Appointments and reassessments will be face-to-face, with instruments validated and adapted for adolescent age groups. The intervention protocol also aims at practicality, ease of execution, and strategies for the patient to easily self-manage and perform independently, adapted for face-to-face or online formats. The Diagnostic Criteria for Temporomandibular Disorders, physical and psychosocial aspects, algometry, near-infrared spectroscopy, and the Tampa scale for kinesiophobia will be used to assess the outcomes.

Discussion

It is expected that this study will contribute to online and face-to-face assessments and demonstrate the differences in the practice of rehabilitation of adolescents with TMD. Data will be published after the study is completed, and if the benefits are proven, care modalities may be implemented.

Trial registration

REBEC—RBR-5scd5tm, UTN code: U1111-1288–4495. Registered on 19 May 2023.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13063-024-08642-4.

Introduction

Background and rationale {6a}

Temporomandibular disorder (TMD) is a public health problem with a multifactorial etiology that is influenced by biopsychosocial factors [9]. Multimodal rehabilitation has shown good results in adults with TMD; however, there is still doubt about the ideal format (in-person or online) and its effectiveness in adolescents who need healthy growth and development; however, there are few studies involving this population. It is more frequent in adults [23], although studies have reported that the symptoms begin during childhood or adolescence, which corresponds to the period of maturation of the musculoskeletal system with hormonal, physiological, and behavioral changes.

Factors related to TMD include kinesiophobia and parafunction, which significantly influence the prognosis [42]. Therefore, it is important that these factors are incorporated into the treatment of adolescents with TMD to avoid perpetuation or progression, since TMD symptoms and harmful oral habits can manifest early and persist into adulthood, leading to serious consequences such as joint overload [23] and pain [27].

In many cases, TMD predominantly affects the muscles, resulting in the reduced availability of circulating oxygen, accumulation of specific metabolites that interfere with muscle contractile function, and increased metabolic demand for functional activities, which generates pain and fatigue [16]. A cross-sectional study investigating hemodynamic variations in the masseter muscle at rest and during contraction in adolescents revealed that those with TMD exhibited reduced levels of oxyhemoglobin compared with healthy individuals, highlighting the need for early intervention in this population [31].

TMD rehabilitation using physiotherapeutic resources aims to conservatively improve biopsychosocial aspects [11]. This approach seeks to alleviate pain, improve function, stimulate proprioception, promote the production of synovial fluid in the joint, and improve the elasticity of muscle fibers [30]. Multimodal physiotherapeutic intervention in TMD is based on the literature, demonstrating positive effects in the short and medium term, with the reduction of signs and symptoms of TMD or its severity. The highlighted modalities included manual therapy (MT), therapeutic exercises, and self-care guidance.

Patient counseling provides autonomy, and responsibility [6, 25], especially when associated with relaxation therapies,thus, showing effective results in chewing muscle pain in patients with TMD [15]. MT is effective in improving the pain, range of motion, function, and severity of TMD [2, 3, 39]; hence, it shows better results when associated with home exercises [10], with training of the craniocervical flexor muscles demonstrating a significant reduction in orofacial pain and headache [4].

Specific exercises for TMD are indicated both in face-to-face physiotherapy [8, 22], and telerehabilitation (TR) [43, 44]. TR can be another vehicle for use in the evaluation or treatment of TMDs, by physiotherapists or health professionals specialized in the area. The advantages of TR over face-to-face treatment include ease of screening, referral, clarification, time, distance optimization, and cost reduction [17, 37]. Some studies have demonstrated the effectiveness of TR in the evaluation and treatment of TMD in adults [8, 14, 20] and in children and adolescents with other conditions [29]. However, investigations on TR and TMD in adolescents are scarce [38].

Objectives {7}

This study aims to describe a multimodal protocol with therapeutic exercises in-person and via telerehabilitation among adolescents with TMD. To evaluate effectiveness, the peripheral muscle oxygenation, pain intensity, range of mandibular movement, kinesiophobia, and parafunction will be assessed.

Trial design {8}

It will be a longitudinal study with a quantitative and analytical nature and is designed as a controlled and blinded randomized clinical trial (RCT) for statistical analyses. We followed the SPIRIT (Standard Protocol Items: Recommendations for Interventional Trials) in the conduction of this protocol.

All participants will be asked to provide written informed consent using standard forms prior to randomization. Participants aged 18 years or parents or guardians of children under 18 years will sign the Free and Informed Consent Form (TCLE) and the consent form for videos, photographs, and recordings. The Free and Informed Assent Form (TALE) will be signed by adolescents under 18 years of age after given a complete explanation of all the procedures.

Methods: participants, interventions, and outcomes

Study setting {9}

Rooms are available at two physiotherapy clinics in different locations to facilitate movement and improve participant adherence. Assessments and face-to-face consultations will take place in these clinics according to the participants’ choice, with each room having the same standard of care and an adequate, lit, and air-conditioned environment. For TR services, participants will be questioned in advance about the quality and stability of their internet network and informed about the need for a silent and illuminated environment, and the use of the social network WhatsApp® via smartphone, as a guarantee of service.

Eligibility criteria {10}

The inclusion criteria were the following: (1) adolescents aged between 10 and 18 years of both sexes; (2) regularly enrolled and attending school activities; and (3) diagnosed with TMD, confirmed by Diagnostic Criteria of Temporomandibular Disorders (DC/TMD), both pain-related TMD or intra-articular TMD subtypes, will be included in this study, since it is a multimodal protocol that covers all aspects of TMDs. The diagnosis will be carried out by a trained examiner. (4) Adolescents with chronic or acute pain, considering that the protocol uses strategies to improve oxygenation and pain reduction, and preventive counseling, that will actuate for both pain modalities. We adopted as a cut-off criterion for pain, classifying pain as acute (less than 3 months) or chronic (more than 3 months) [40].

The following exclusion criteria will be adopted: (1) adolescents who presented with neurological or respiratory diseases, musculoskeletal disorders, or other disabilities that may interfere with understanding or carrying out the protocol; (2) received physiotherapeutic care (for the region to be treated, within 3 months prior to the evaluation) or medication treatment (analgesics and/or muscle relaxant) 24 h before the evaluation; and (3) used an orthodontic appliance (mobile or fixed) or interocclusal splint.

Who will take informed consent? {26a}

Before commencing the intervention, written documentation of informed consent is acquired subsequent to approval by the Ethics Committee. Upon meeting the inclusion criteria, adolescents aged over 18 years or their parents/legal representatives, in the case of minors under 18, will be furnished with a comprehensive parent information packet (comprising the Free and Informed Consent Form, the Free and Informed Assent Form, and the Consent Form for photographs, videos, and recordings), elucidating details about the trial and intervention. They retain the prerogative to withdraw their child from the trial at any juncture and for any reason, without impeding the child's ongoing treatment.

Additional consent provisions for collection and use of participant data and biological specimens {26b}

This trial does not involve collecting biological specimens for storage.

Interventions

Explanation for the choice of comparators {6b}

The chosen comparison variables were pain, ROM function, and main points of physiotherapeutic treatment, with the variable peripheral muscle oxygenation, a distinguishing feature of this study.

Intervention description {11a}

After the initial evaluations, randomization will be performed for the distribution of individuals in the following groups: (1) face-to-face group (GF) and (2) telerehabilitation group (GT).

Initially, an evaluator will categorize participants into the eligibility criteria by collecting information related to personal data, mass, height, body mass index, medical history, previous illnesses, concomitant illnesses, use of interocclusal devices, medications, previous surgeries, physiotherapy, and other aspects.

After screening, acceptance, and signing of ethical terms, anamnesis will begin with participant identification data, demographics, anthropometric assessment, and assessment using the DC/TMD to confirm the diagnosis.

This multimodal rehabilitation protocol used guidance resources, manual therapy, and exercises, and are in Table 1, which were considered low-cost resources based on the literature. We sought to simplify them to allow self-management.

Table 1.

Multimodal rehabilitation protocol

	GF	GT
Intervention	3 weekly sessions Face-to-face physiotherapy 30 min each session	3 weekly sessions Online physiotherapy (telerehabilitation) 30 min each session
Counseling (10 min)	T – Thermotherapy (heat or cold) E – Exercises (home) P – Posture (tongue, jaw, head) E – Explanation (ATM, DTM) D – Decrease parafunction I – Importance of quality of life (sleep, physical activity, relaxation, breathing)	T – Thermotherapy (heat or cold) E – Exercises (home) P – Posture (tongue, jaw, head) E – Explanation (ATM, DTM) D – Decrease parafunction I – Importance of quality of life (sleep, physical activity, relaxation, breathing)
Manual therapy (10 min)	M – Myofascial release in masticatory muscles (IO and EO) A – Articular mobilization (TMJ) (nonspecific) N – Myofascial release in neck muscles	M – Myofascial release in masticatory muscles (IO and EO) – N – Myofascial release in neck muscles
Exercises (10 min)	M – Masticatory muscles isometric and isotonic exercises (IO and EO) A – Articular movement (TMJ “N position”) N – Neck musculature (postural exercises and stretching)	M – Masticatory muscles isometric and isotonic exercises for the jaw muscles (IO and EO) A – Articular movement (TMJ “N position”) N – Neck musculature (postural exercises and stretching)

Legend: GF face-to-face group, GT telerehabilitation group, TMJ temporomandibular joint, TMD temporomandibular disorder, IO intraoral, EO extraoral

The protocol will be applied online and in-person. The choice of 3 sessions was based on the satisfactory results of recent RCTs, which carried out a few (2 to 5) physiotherapy sessions in the treatment of musculoskeletal disorders of the head and neck region [18, 33].

Treatment interventions were standardized to improve the internal validity of the design and allow for ease of replication in future clinical trials or by professionals in their work environments. The GT intervention will take place synchronously remotely via video call via WhatsApp® and as can be seen in Table 1, the GT protocol will be similar to the GF, except for two basic differences in manual therapy and articular manipulation.

Counseling

The guidelines in this protocol include care, advice, pain education, and stress management strategies, which will be clarified at the beginning of each session, so that participants can learn and incorporate them into their daily lives. This promotion of autonomy for the patient [6] and their responsibility towards the treatment, promotes a more powerful result with a change in the general perception of pain and a reduction in recurrences [25]. To make it easier for participants and examiners to remember each orientation, the author created the acronym “TEPEDI,” which refers to the initials of thermotherapy, exercises, posture, explanation, lying down, and the importance of quality of life.

“T” for thermotherapy, which can be carried out at home with a cold or heat pack, to reduce pain or relax muscles [9]. “E” home exercises, which must be repeated every day, as taught in the sessions [43] and verified for their correct and satisfactory execution [9]. The GF and GT participants will be instructed to repeat the exercises, self-massage, and all instructions at home daily. “P” for correct posture in resting the tongue, jaw, head, and shoulders,the tongue should be on the hard palate and the jaw relaxed [26], the head aligned with the dorsal column with the shoulders lowered [26]. “E” for explanation, the patient who receives an explanation and understands the use of TMJ and the precipitating and predisposing factors of TMD, may have a better prognosis and adherence to treatment [25]. “D” for decreased parafunction and unclenched teeth from contact, in order to manage parafunctional habits, which can be remembered and made aware through post-it notes or through the “Desencoste” app. Participants will be informed that when the jaw is at rest, their teeth should not touch, except when swallowing or eating [7, 9]. “I” to remember the importance of basic habits in the quality of life, such as sleep hygiene [34], the practice of physical activity [28], and relaxation. This relaxation can be done in several ways and in this protocol, diaphragmatic breathing was used, with re-education of the breathing pattern, stimulation of the diaphragm, and relaxation of the accessory respiratory muscles [41].

Manual therapy

The manual approaches to this protocol include passive myofascial release (in GF) or self-massage (in GT), and it is demonstrated in Fig. 1, with guidance that this pressure is gentle and comfortable manner depending on individual tolerance. A previous study [12] showed that myofascial release applied for 10 min to the trapezius muscle was effective in the hemodynamic variable of the total saturation index (TSI), which reinforces the choice of technique and application time chosen in this RCT. The participants in both groups will still be instructed to add self-massage to their daily self-care tasks. To facilitate the checklist for each region to apply MT, the acronym “MAN” was created, which refers to the initials of the regions: masticatory muscles, articulation TMJ, and neck.

Fig. 1.

Demonstrative image of manual therapy of the protocol. A Cervical region, B and C extraoral masticatory muscles, D and E intraoral region in face-to-face care

Masticatory muscles: Manual therapy of the masticatory muscles in the intraoral and extraoral regions [3]. It will be performed in the GF and GT groups. In the IO maneuver, the patient will be instructed to place the contralateral thumb on the mandible that will receive the maneuver, and the other fingers must rest on the external region of this cheek. Attention will be placed on some details upon carrying out the maneuver, including the use of gloves in the GF, hygiene of hands, and whether the patient is free from internal injuries or limitations that cause discomfort.

TMJ: Non-specific joint mobilization of the TMJ, with rhythmic, oscillatory movement, in the posteroanterior direction, for 1 min 30 s, 3 to 5 times, with an interval of 30 s between series [9]. This maneuver will only be performed in the GF.

Neck muscles: Manual therapy in the posterior and anterior region of the muscles neck (scalene, sternocleidomastoid, trapezius, elevator scapula, suboccipital, supra, and infrahyoid muscles) [41]. This maneuver will be performed in both groups.

Therapeutic exercises

Patients will be informed of the objective of each exercise, the need to communicate in the event of pain, caution in each performance, and pauses to avoid muscle fatigue [24]. The regions that will receive the exercises will be the same as those of the TM,therefore, the same acronym “MAN” was used for the checklist of the “masticatory” muscles, TMJ “articulation”, and “neck” muscles. The use of a mirror will be recommended in favor of awareness in movement, correcting deviations, and excessive amplitude, minimizing joint noises; thus, which facilitates learning, since the exercises will be advised to be repeated at home every day [8]. A 30-s rest interval will be recommended between each exercise. The exercises aim to achieve muscle relaxation and optimize function.

The jaw exercises will be isotonic and isometric and are demonstrated in Fig. 2: isotonic exercises in a free and maximum range of motion for all mandibular ranges (lateralization, opening, closing, protrusion, with 6 repetitions of each movement) [8, 22]. Strengthening isometrics, with small resistance given by the fingers, and tongue on the palate, for all mandibular ranges (lateralization, opening, closing, protrusion, with 6 repetitions of each movement) [8, 9, 22, 41].

Fig. 2.

Demonstrative image of the temporomandibular joint and mandibular exercises. A N position exercise, B isotonic opening exercise, C and D isotonic laterality exercise, E isometric strengthening exercise in protrusion, F opening isometric, G and H laterality isometric, I jaw closing isometric

The TMJ exercise chosen was the “N position” with opening and protrusion of the mouth with the tongue on the palate (3 sets of 10 repetitions, 30-s intervals) [8, 9, 13, 24, 32].

The exercises for the neck region are demonstrated in Fig. 3, and it will be as follows: stretching in all planes of movement (extension, flexion, rotation and inclination right and left, inclination with flexion, six repetitions of each movement), self-growth exercise correcting posture and seeking alignment (for 1 min) [21, 41] and an anterior skull rotation exercise by nodding the head (six times out of six repetitions) [32].

Fig. 3.

Demonstrative image of exercises for the neck region. A In cervical flexion, B in lateral inclination, and C in lateral inclination associated with cervical flexion

Criteria for discontinuing interventions {11b}

The criteria for halting interventions for a trial participant encompass adolescents who request a temporary suspension for personal reasons or whose deteriorating condition prompts them to withdraw from active participation.

Strategies to improve adherence to interventions {11c}

Two clinics will be available, in different locations, in the city of Florianópolis (Brazil), in order to facilitate movement and improve participant adherence. In-person assessments and consultations take place in these clinics according to the participant's choice. In addition, there will be flexibility in scheduling times, and patients will receive reminders and videos of exercises and care at home.

Relevant concomitant care permitted or prohibited during the trial {11d}

During this training, adolescents will not be able to undergo other treatments such as the use of an interocclusal splint, medications, or other physiotherapy services, other than those offered in this protocol, nor will they be able to start using orthodontic appliances.

Provisions for post-trial care {30}

As a form of care post-trial, all participants will receive a report with the results of the instruments used, as well as care guidelines and home exercises.

Outcomes {12}

Each group will undergo an initial assessment (T0), followed by three treatment sessions: an immediate reassessment (which will be carried out 0–2 days after the third session [T1]), another reassessment 30 days after the end of treatment, and treatment follow-up (T2). Assessments and reassessments will be performed in-person.

In addition to the physical aspects of DC/TMD and anthropometric assessment through mass and height measurements, the following instruments will be used: digital pressure algometer, graduated chronic pain scale (GCPS), pain drawing for pain assessment, infrared spectroscopy (NIRS) to assess peripheral muscle oxygenation, Tam scale (TSK/TMD) to assess kinesiophobia, and other psychosocial scales of DC/TMD, such as Generalized Anxiety Disorder 7-item (GAD7), Patient Health Questionnaire-4 (PHQ4), Oral Behaviors Checklist (OBC), and Jaw Functional Limitation Scale-8 (JFLS8). The assessment will last an average of 60 min, and the treatment sessions will last 30 min [43], with 10 min of guidance, 10 min of manual therapy and relaxation, 10 min of specific exercises, and reassessments lasting 40 min. This 3-session protocol will occur weekly. In reassessments, the same assessment instruments will be applied, with the exception of the GAD7 and PHQ4, as these will only be used to characterize the sample. Finally, all participants will receive a report with the results of the instruments used, as well as care guidelines and home exercises.

Diagnostic criteria of temporomandibular disorders—axis 1—physical assessment

For the diagnosis of TMD and clinical evaluation of the TMJ, the validated Portuguese version of the DC/TMD will be used, which classifies between myalgia, arthralgia, headache attributed to TMD, disc displacement, degenerative joint disease, or subluxation. There may be more than one diagnosis for each participant. This stage lasts an average of 15 to 20 min and will follow the regulations of the Delphi study Axis 1 of the DC for adolescents [5, 35]. Range of motion (ROM) measurements will be taken with a digital universal caliper.

Diagnostic criteria of temporomandibular disorders—axis 2—psychosocial assessment and pain

Axis 2 of the DC/TMD allows for psychosocial assessment and determination of the consequences of pain. Some suggestions from the Delphi study [36] for adolescents will be used, such as the GCPS, Pain Drawing, JFLS8, and OBC scales. Even though some questionnaires may be self-administered [9], it was decided to have one examiner (examiner “A” or “B”) accompany each participant, in order to accommodate doubts, check and reduce biases.

Tampa scale for kinesiophobia for temporomandibular disorders

The Tampa Kinesiophobia Scale for TMD (TSK/TMD) is a self-administered questionnaire with 18 questions, translated and cross-culturally adapted, and is valid and reliable for assessing kinesiophobia in patients with TMD [1].

Near-infrared spectroscopy

To obtain hemodynamic variables with high resolution in real time, such as oxyhemoglobin (HbO2), deoxyhemoglobin (HHb), total hemoglobin (tHb), tissue saturation index (TSI), and the near-infrared spectroscopy (NIRS) (Portamon®, Artinis, Netherlands), with an acquisition frequency of 10 Hz, in a non-invasive evaluation phase that lasts 5 min will be used [45].

The chosen muscle, positioning, and method that will be used were based on an oximetry study in adolescents with TMD [31], which evaluated the masseter muscle bilaterally, as it is involved in chewing in TMDs.

Oxygenation will be measured at two time points: with the muscle at rest (jaw relaxed and teeth disengaged) for 60 s, during muscle contraction (in dental occlusion), followed by the maximum voluntary isometric contraction of the masseter muscle for 20 s, and at moments T0, T1, and T2 of the ECR protocol. The side to start measuring the device was chosen randomly. For the purpose of dental protection, to contract the masseter, a parafilm (Pechinery® Plastic Packaging, USA) folded 15 times to a size of 1.5 cm by 3.5 cm will be used, which will be positioned between the occlusal surfaces of the first and second upper and lower molars.

Pressure algometry

To evaluate the pressure pain threshold (PPT), a digital pressure algometer from the brand MedEOR® model SP Tech, will be used, which allows for real measurement of pain thresholds and tolerances by mechanical pressure. These are two measurable and useful neurophysiological methods for clinical practice, which assess pain in an objective manner (MedEOR® Medtech LTDA, Brazil, 2018).

The position the participant will adopt, as well as the handling of the algometer, was based on a previous study [19], which evaluated the masseter and temporalis muscles bilaterally. The side to start measuring the device was chosen randomly. Pressure was applied until the volunteer complained of pain, indicated by raising the arm, and the value was recorded on an algometer display (kg/cm²). The PPT was measured three times at each location, with an interval of 5 s between each measurement, and the average was used for statistical analysis. Table 2 summarizes the instruments used, their scores, evaluations, and their respective classifications.

Table 2.

Data collection instruments used in the research

Instrument	Number of items	Score	What will be evaluated	Classification
Near-infrared Spectroscopy (NIRS)	4	–-	Peripheral muscle oxygenation variables (oxyhemoglobin, deoxyhemoglobin, total hemoglobin, and tissue saturation index)	Depends on each variable
Algometer	–-	–-	Pressure pain threshold	–-
Characteristic intensity of pain (CPI)b	3	0–100	Current pain level Average pain in the last 30 days Worst pain in the last 30 days	Painless Low pain High pain
Drawing of paina	–-	–-	Location of pain Number of affected areas Pain spreading area	0 = none 1 = light 2 = moderate 3 ≥ severe
Generalized Anxiety Disorder (GAD-7)a	7	0–21	Anxiety dcreen	0–4 = none 5–9 = mild 10–14 = moderate 15–21 = severe
Patient Health Questionnaire (PHQ-4)a	4	0–12	Ultra brief screening of depression and anxiety	Classification not established (The higher the score, the greater the limitation)
Examination form (FE)a	10	–-	Presence or absence of TMD Type of TMD	Myalgia Arthralgia Headache attributed to TMD Disk displacement Degenerative joint disease Subluxation
Symptom Questionnaire (QS)a	14	–-
Mandibular Functional Limitation Scale (JFLS-8)a	8	0–10	Mandibular function	Classification not established (the higher the score, the greater the limitation)
Oral Behavior Checklist (OBC)a	21	0–84	Parafunctional habits	0 = None 1–24 = low 25–84 = high
Tampa Scale (TSK TMD)	18	18–72	Kinesiophobia	Classification not established (the higher the score, the greater the kinesiophobia)
Numerical Pain Scale (NPS)b	10	0–10	Current pain level	0 = no pain 1 to 3 = mild pain 4 to 6 = moderate pain 7 to 10 = severe pain

^aScales belonging to the DC/TMD group

^bScales obtained from the GCPS questionnaire (Graded Chronic Pain Scale). The characteristic pain intensity (CPI) scale was obtained using the values of questions 2 (pain at the exact moment of assessment), 3 (worst pain in the last 30 days), and 4 (average pain in the last 30 days) from the GCPS questionnaire. NPS scores were obtained using Question 2 of the GCPS

The Clinical Relevance of this study is that a multimodal face-to-face and telerehabilitation protocol for adolescents with TMD will be presented, and this protocol could serve as a basis for future research in this area and it can be easily used for clinical practice.

Participant timeline {13}

The participant’s timeline can be observed through the flowchart in Fig. 4.

Fig. 4.

Flowchart of the trial design

Sample size {14}

For the sample calculation, the G Power program version 3.1.7 was used based on oxyhemoglobin data in adolescents with TMD [31], which represents the same population of this trial, and also, the authors used the same NIRS equipment,thus, the physiological variable, peripheral muscle oxygenation, was chosen as the primary outcome to calculate the sample size. The final sample size was 26 adolescents, with a significance level of 5% and power of 80%, the same significance and values used by a previous study [14]. The 26 adolescents will be randomized into two groups with 13 participants in each group.

Recruitment {15}

Patients will be recruited from communities located in the metropolitan area of Florianopolis City, south of Brazil, by means of announcements, pamphlets, posters, emails, social media, and invitations through schools.

Assignment of interventions: allocation

Sequence generation {16a}

A random sequence of participants distributed proportionally in each study group will be performed using the website, randomization.com.

Concealment mechanism {16b}

The concealed allocation of individuals will be accomplished using sealed and opaque envelopes. Randomization and concealed allocation will be performed by an independent researcher, who will not be involved in the recruitment, evaluation, or intervention processes.

Implementation {16c}

Examiner X, which will not be involved in the recruitment, evaluation, or intervention processes, will allocate the participants, and collect the signatures of the ethical terms. The interventions will be made by examiners A and B. All stages of the DC/TMD axis 1, algometry and oximetry, will be carried out by the same examiner (examiner “A”), trained and experienced in the area of TMD for 20 years, with the intention of reducing biases. The other questionnaires will be administered by examiner “A” and examiner “B,” also trained and qualified. All GF sessions will be carried out by the same physiotherapist and an experienced clinician in the area (examiner A). The GT sessions will be conducted by examiners A and B. The groups (GT and GF) will receive similar care; however, in the manual therapy stage (TM), the GT group will be guided to perform self-massage, while the GF group will be massaged by the physiotherapist.

Assignment of interventions: blinding

Who will be blinded {17a}

This protocol will be blinding only for statistical analysis, by examiner “C.” Given the logistical and regulatory challenges in implementing randomization and intervention, examiners X, A, and B will not be feasible.

Procedure for unblinding if needed {17b}

The design of the study is open-label, with only the outcome assessors being blinded, thus preventing unblinding.

Data collection and management

Plans for assessment and collection of outcomes {18a}

Participant data will be collected by researchers and stored anonymously in Google Drive. The data will be stored in accordance with the country’s Data Protection guidelines. Examiner A received training for face-to-face assessment and treatment and has experience in the area for over 20 years. A database was included in the study folder accessible to all researchers. There will be several moments for data entry: screening, initial assessment, immediate reassessment, and follow-up.

Plans to promote participant retention and complete follow-up {18b}

Patients will receive confirmation and reminders of the scheduled treatment date, and this will facilitate reaching the calculated sample size, as well as careful reminders of the advice they should take.

Data management {19}

The Google Drive platform will be used for data management and storage of study data (in a database), including data backup. The data will be validated according to the data validation plan. After carrying out all data validation and the final review, the study database will be considered complete and the data it contains is reliable. As soon as the study is concluded, the study database will be closed and transferred to the blinded Team of biostatisticians for data analysis, with codes to avoid the groups’ identification. At the end of the study, a copy of the site-specific document. Records will be provided to each principal investigator. Data will be validated according to the data validation plan.

Confidentiality {27}

The study staff will ensure that the participant´s anonymity is maintained. The participants will be identified only by a participant code on the case report forms (eCRF) and any electronic database. All documents will be stored securely and only accessible by study staff and authorized personnel. Applicable regulations for storage, transmittal, and disclosure of patient information will be followed at all times. The study will comply with the Data Protection Legislation in each country. Following formal admission to the study, patient data will be recorded in the Clinic case record in the usual way including the circumstances of their entry to the study. Additionally, data will be held in eCRF. These files will be identified by a study code, date of birth, and participant code only. Representatives from the Sponsor and from the regulatory authorities will be given access to the records that relate to the study. They will have full access to the anonymous eCRFs for the purposes of data validation. The results of the study may be communicated at scientific meetings and will contribute to the scientific literature. At no time, this will be done in such a way that an individual participant may be identified.

Plans for collection, laboratory evaluation, and storage of biological specimens for genetic or molecular analysis in this trial/future use {33}

See above 26b; there will be no biological specimens collected.

Statistical methods

Statistical methods for primary and secondary outcomes {20a}

The primary outcomes will be masseter oxygenation, pain, and range of motion. The secondary outcomes will be parafunction and kinesiophobia.

Descriptive analysis will be performed with the calculation of mean and standard deviation; minimum, maximum, and median values for quantitative variables; and frequencies and percentages for categorized variables, stratified by group at baseline. Statistical analysis will be conducted based on an intention-to-treat analysis. Thus, individuals will be analyzed in the groups to which they were randomly allocated. Histograms will be used to verify the data distribution.

Baseline means comparisons will be made using the Student’s t-test for asymmetric data. Mean questionnaire scores will be compared using a Poisson distribution fit. Associations between the categorized variables and groups will be assessed using the chi-square test. The evaluation of group means and evaluations will be performed using a repeated-measures model to test the interaction between groups and evaluations. For symmetric data, ANOVA will be used, followed by Tukey's multiple comparison test. The scores will be evaluated by fitting a Poisson distribution model, followed by Wald’s multiple comparison test. Pearson’s correlations between the pain and oximetry variables will be obtained. Statistical significance was set at p-value 5%. All analyses will be performed using SAS for Windows, v.9.4.

The outcomes will also be compared by analyzing the minimum important clinical differences in relation to pain intensity, range of movement, and pressure pain threshold [5].

Interim analyses {21b}

No detrimental problems to the study participants are anticipated. No interim analyses are planned.

Methods for additional analyses (e.g., subgroup analyses) {20b}

Important prognostic variables are in the complex diagnoses. Further subgroup analysis will be conducted in line with the primary analysis. For continuous endpoints, similar modeling strategies will be used, but instead of logistic regression linear regression models will be used. External statistical assistance was hired, which had no contact with the study data collection.

Methods in analysis to handle protocol non-adherence and any statistical methods to handle missing data {20c}

Missing data in Clinical Trials, sensitivity analyses will be conducted with diverse strategies for handling missing data, incorporating adjustments for clustering. This will encompass considering missing data scenarios such as completely at random, missing at random, and missing not at random.

Plans to give access to the full protocol, participant-level data, and statistical code {31c}

The datasets analyzed during the current study and statistical code are available from the corresponding author on reasonable request, as is the full protocol.

Oversight and monitoring

Composition of the coordinating center and trial steering committee {5d}

In the trial, the School Clinic of Santa Catarina State University (UDESC), served as the coordinating center and trial steering committee. It comprised the chief investigator, technical coordinator, financial officer, and legal officer. Additionally, each participating center had its own chief investigator overseeing the trial’s day-to-day operations.

Composition of the data monitoring committee, its role and reporting structure {21a}

Due to the nature of the intervention, which does not concern a medical drug and does not propose extra risk to adolescents, the implementation of a Data Safety Monitoring Board is not deemed necessary.

Adverse event reporting and harms {22}

Given the intervention’s nature and the patient population’s potential for complications inherent to their biological or medical state, individual reporting of serious adverse events will not occur. Instead, they will be incorporated into the data collection process for assessing benefits and risks.

Frequency and plans for auditing trial conduct {23}

The electronic data entry system furnishes an audit trail, enabling identified and authorized users to remotely deposit data into the eCRFs. This ensures that all data entries and modifications made by sites in the central database are automatically and chronologically documented.

Plans for communicating important protocol amendments to relevant parties (e.g., trial participants, ethical committees) {25}

Our communication strategies for significant protocol modifications emphasize the prompt and direct distribution of information to all pertinent stakeholders. This encompasses investigators, Research Ethics Committees/Institutional Review Boards (REC/IRBs), and trial registries. Through streamlined communication channels, we will guarantee timely dissemination of updates, enabling stakeholders to remain informed and adapt or decide as needed.

This is the third version of the protocol presented to the C Research Ethics Committee of the State University of Santa Catarina, to comply with Consubstantiated Opinion number 5,605,641 issued on October 10, 2022, CAAE 60845922.4.0000.0118.

Dissemination plans {31a}

The trial funding will undergo consideration for publication and presentation at scientific symposia or congresses. As participant data will be recorded anonymously, utmost care will be taken to ensure participant privacy. The results obtained from the trial will contribute to the enhancement of existing guidelines and enable the publication of new ones. Additionally, we will explore the possibility of conducting stakeholder workshops to engage with relevant groups and gather valuable perspectives.

Discussion

This trial will verify and compare the effect of a multimodal intervention in the online TR and in the face-to-face format, in among adolescents with TMD, in terms of peripheral oxygenation of the masseter muscle, pain, range of motion, kinesiophobia, and parafunctional habits, highlighting the evaluation of the outcomes of the biopsychosocial sphere affected by patients with TMD.

Furthermore, high internal validity is expected because this protocol was designed for randomization, concealed allocation, blinding for statistical analysis, intention-to-treat analysis, and adequate sample size with calculations considering the primary outcome.

This study is a pioneer in comparing multimodal treatment among adolescents with TMD in face-to-face and TR formats, but it has some limitations. Owing to the nature of the proposed interventions, the physiotherapist responsible for implementing the treatment will not be blinded, nor will the participants know to which group they belong to. The need for an available Wi-Fi environment and network as well as the importance of engaging with families in teenagers’ participation can also be considered.

The aim of this study was to contribute to technical-scientific advancement, supporting the clinical applicability of in-person and online multimodal rehabilitation based on evidence for the age group of adolescents with TMD, through a 3-session protocol, reducing comorbidities and costs of the disease, and generating better development and quality of life for this age group. This protocol could serve as a basis for future research in this area and has the advantage of being accessible to health professionals using tools easily found in clinical practice, such as biopsychosocial assessment, self-management, and pain education, which are part of the current scenario of evidence-based physiotherapy. The data will be published after the completion of the study.

Trial status

This manuscript is based on the trial protocol “Exercises applied online and multimodal intervention face to face: randomized controlled clinical trial in adolescents with Temporomandibular Dysfunction”. The project began in June 2022, and patient enrollment began in October 2022, and the recruitment began in November 2022. The study is in the main study phase. This study was registered in the Brazilian Registry of Clinical Trials (REBEC—RBR −5scd5tm, UTN: U1111-1288–4495), registered in May 2023. This is the third version of the protocol presented to the C Research Ethics Committee of the State University of Santa Catarina, to comply with Consubstantiated Opinion number 5,605,641 issued on October 10, 2022, CAAE 60845922.4.0000.0118. The entire study is scheduled to be completed by the end of December 2025.

Abbreviations

ANOVA

Variance analysis

CPI

Characteristic intensity of pain

DC/DTM

Diagnostic Criterio for Temporomandibular Disorders

FUP

Follow-up

GAD7

Generalized Anxiety Disorder 7-item

GCPS

Graded Chronic Pain Scale

GF

Face-to-face group

GT

Telerehabilitation group

HbO2

Oxyhemoglobin

HHb

Deoxihemoglobin

JFLS8

Jaw Functional Limitation Scale 8-item

T0

Initial assessment

T1

Immediate reassessment

T2

Follow-up

Kg/cm2

Quilograma força por centímetro quadrado

MDCI

Mínima diferença clínica importante

MT

Manual therapy

NIRS

Near-infrared spectroscopy

NPS

Numeric pain scale

OBC

Oral Behaviors Checklist

PHQ4

Patient Health Questionnaire 4-item

PPT

Pressure pain threshold

RCT

Randomized clinical trial

REBEC

Brazilian Registry of Clinical Trials

ROM

Range of movement

TALE

Free and Informed Assent Form

TCLE

Free and Informed Consent Form

tHb

Total hemoglobin

TMD

Temporomandibular disorders

TMJ

Temporomandibular joint

TR

Telerehabilitation

TSI

Tissue Saturation Index

TSK-TMD

Tampa Scale for Kinesiophobia for TMD

UDESC

Santa Catarina State University

Authors’ contributions {31b}

Andreza Garrett (AG): conceptualization, methodology—protocol creation, investigation, writing—original draft. Daniela Biasotto Gonzalez (DBG): conceptualization, formal analysis, writing—review and editing. Anelise Sonza (AS): conceptualization, methodology, formal analysis, writing—review and editing.

Funding {4}

This work had no funding.

Data availability {29}

Research data will be stored via a web-based electronic clinical service trial data management system. Direct access tp the source data will be granted to authorized representatives of the Sponsor or delegated organization, institution, Ethics and Regulatory Committees Authorities related to studies for monitoring, audits, and inspections.

Declarations

Ethics approval and consent to participate {24}

This study was approved by the Ethics Committee Involving Human Beings of Santa Catarina State University (CAAE: 60845922.4.0000.0118, protocol number 5.707.485).

Consent for publication {32}

The Clinical Publication Committee shall deal with all aspects regarding Publications from this protocol. Partners interested in producing publications shall submit a 1–2-page proposal to the CPC for approval.

Competing interests {28}

The authors declare that they have no competing interests.