Minimally invasive techniques in the management of muscular temporomandibular joint disorders: A five-year observational study

Background To evaluate the effectiveness of three minimally invasive techniques for managing patients with myofascial pain dysfunction, determine their association with sociodemographic factors, habits, medication usage, comorbidities, treatment history, pain duration, complaint intensity, and diagnosis limitations. Material and Methods This five-year observational study scrutinized 1,000 medical records from individuals treated at the TMD Orofacial Dental Research Center. TMD treatments were organized into Group 1 (thermotherapy, exercises, and CBT), Group 2 (Group 1 plus intramuscular manual therapy), and Group 3 (Group 1 and Group 2 plus occlusal appliances) and correlated with sociodemographic factors, habits, prior medication usage, comorbidities, history of prior treatments, duration of pain, intensity of complaint, and diagnosis limitations or without limitations regarding the symptoms of muscular temporomandibular disorders (TMD). Results Treatment durability was proportionally higher in Groups II and III (p<0.05). Although no significant differences were found for habits (p= 0.051) and pain duration (p= 0.001), clenching was more prevalent in Groups II n= 77 (57.0%) and III n= 39 (63.9%) and among those with therapy duration equal to or greater than 6 months for n=102 (59.3%). Statistically significant correlations were noted between age and education (rho=-0.198; p<0.001) and between pain duration and treatment durability (rho=0.317; p<0.001). Conclusions Intraoral devices do not constitute the primary treatment for myofascial pain. For cases of prolonged pain, comorbidities, limited mouth opening, and a history of prior medication or treatments, a splint combined with other therapies is recommended for effective management. Key words:Temporomandibular disorders, myofascial pain, occlusal appliances, clinical diagnosis, thermotherapy, exercise therapy, cognitive behavioral therapy.


Introduction
Temporomandibular disorders (TMD) represent a diverse spectrum of multifactorial conditions affecting the temporomandibular joint (TMJ), muscles, articulation, and facial nerves, characterized by functional alterations in the masticatory apparatus (1).Identifying a single triggering etiological factor is challenging due to their multifactorial origin, arising from a complex interplay of psychological, structural, and postural factors that can disrupt the masticatory muscles and temporomandibular joint (2,3).Psychological conditions, often associated with tension leading to bruxism (teeth grinding and clenching), have been linked to the development of TMD (4,5).The literature highlights a diverse range of treatments for temporomandibular disorders with muscular origin, involving individualized combinations of therapies.These options include counseling, physiotherapy, jaw exercises, pharmacologic interventions, behavioral medicine, and physical therapies such as acupuncture, dry needling, transcutaneous electrical nerve stimulation (TENS), and the use of heat and cold applications, along with occlusal appliances (6)(7)(8).Occlusal appliances have traditionally been a common treatment for painful TMDs, yet the evidence base for their efficacy remains unclear and subject to questioning (9).Potential mechanisms include alterations in the reflective pattern of the masticatory muscles, reduction in loading on the masticatory muscles and TMJs, heightened awareness of parafunctional activity, or a placebo effect (10)(11)(12)(13).Previous studies combining occlusal splint treatment with other modalities have demonstrated impressive results in clinical symptoms, reflecting the complexity of TMD management (15,16).A systematic review, assessing the efficacy of occlusal appliances in managing painful TMDs, explored the role of the placebo effect.Contrary to expectations, patient-reported treatment satisfaction extended beyond pain intensity, including improvements in physical functioning and psychosocial factors, suggesting a treatment effect beyond placebo (17).Lastly, this five-year observational study aims to compare minimally invasive techniques for managing myofascial pain in patients, considering the presence or absence of opening mouth limitations.

-Design and patient data collection
Observational study based on an analysis of clinical patient records was performed at the Temporomandibular Dysfunction and Orofacial Pain Clinic of the Dental Research Center between May 2015 and March 2020.A pilot study determined the sample size (n) with an estimated target population of 480.Ensuring reliable statistical analyses, a sample size of 348 files was calculated based on the Central Limit Theorem and the Laws of Large Numbers, assuming a 3.0% error rate.
The anonymized patient data had the following patient inclusion criteria: • Over 18 years of age, of both genders • Diagnosed with myofascial pain with or without limitation of mouth opening (Ia and Ib) according to the Research Diagnostic Criteria for Temporomandibular Disorder (RDC/TMD) Axis I (18).Whereas the exclusion criterion was clinical files with incomplete data.
-Evaluated minimally invasive techniques The TMD treatment techniques were organized into three groups: • Group 1: Thermotherapy, therapeutic exercises, and cognitive-behavioral therapy (CBT).
• Group 3: Therapies from Group 1, Group 2, and occlusal appliances.These therapies in Groups I, II, and III were correlated with sociodemographic factors, habits (clenching, oncophagia, biting lips, posture), prior medication usage (yes or no), comorbidities (absent or exist), history of prior treatments (yes or no), duration of pain (up to 6 months, 6 months or more), intensity of complaint (light, moderate, or more), and diagnosis with clinical limitations or without limitations regarding TMD symptoms (myofascial pain, myofascial pain with limited opening, disc displacement with reduction, and arthragy).
-Statistical analysis Data were presented using absolute (n) and relative frequency (%).Chi-square tests were employed for comparisons based on therapy type and treatment time.Spearman correlation coefficients assessed relationships between age, education, duration of initial complaint, and treatment time durability.Crude and adjusted multinomial logistic regression models examined associations of sociodemographic, behavioral, and health-related characteristics with therapy type, using Therapy I as the reference.The backward model (Wald) excluded variables with p > 0.10 for adjusted analysis.The association of sociodemographic, behavioral, and health-related characteristics with treatment duration was assessed using crude and adjusted binary logistic regression models.Treatment durability up to 6 months was the reference category.The backward model (Wald) excluded variables with p > 0.10.All analyses were conducted using SPSS Statistics for Windows, version 26.0, with a significance level of p < 0.05.

Study population and sociodemographic characteristics
In adherence to inclusion criteria, 348 dental records were analyzed from a total of 1,000, with exclusions attributed to insufficient data.A detailed descriptive e604 analysis explored the correlation between behavioral characteristics, patients' medical history, and treatment outcomes.No statistically significant differences were observed in sociodemographic characteristics based on therapy type and treatment durability (p>0.05).The majority of participants were female, aged 40 or older, possessing a graduate degree, and engaged in some form of job occupation (part-time or full-day) (Table 1).-Treatment durability analysis by therapy type Table 6 provided a detailed analysis of treatment durability for the three therapies adopted.In Group I, the average treatment duration was 5.4 months, ranging from 2 to 12 months, with 50% completing treatment within a maximum of 5 months.In Group II, the average treatment duration was 7.5 months, ranging from 2 to 23 months, with 50% completing treatment within a maximum of 7 months.In Group III, the average treatment duration was 10.5 months, ranging from 6 to 20 months, e605  with 50% completing treatment within a maximum of 10 months.

Discussion
The   (24).The efficacy of Group I therapy prompts a reevaluation of intraoral devices as the first-choice treatment for myofascial pain.This aligns with previous studies, emphasizing the impact of occlusal splints as additional treatment, impacting psychological aspects (25)(26)(27).
Another study comparing the efficacy of combination therapy (splint therapy, physiotherapy, manual therapy, and counseling) with physiotherapy, manual therapy, and counseling suggests both approaches in myogenic TMD management (27).As this study relies on medical record data, it assumes an observational design, limiting control over certain factors and potentially introducing bias.Future well-designed, randomized controlled studies are imperative for a comprehensive assessment of managing myofascial pain.

Conclusions
Within the limitations of this comparative observational study, the following conclusions can be drawn: 1. Intraoral devices are not the preferred first-line treatment for myofascial pain.
2. Patients without prior treatment, with pain less than 6 months, may be managed with behavioral intervention and thermal intervention in relation to the control of muscular TMD.
3. Patients with prior treatment and pain persisting over 6 months, a combination of behavioral intervention and thermal therapy, along with dry needling, appears effective in optimizing myofascial pain control in the masticatory muscles.4. Patients with prolonged pain duration, comorbidities, limited mouth opening, a history of medication use, and prior treatments may benefit from the use of a splint in conjunction with other therapies for effective management.

Table 1 :
Sociodemographic characteristics in relation to the adopted therapy type and treatment duration. Chi-square.

Table 2 :
Behavioral and injury characteristics according to the type of therapy adopted and duration of treatment.

Table 3 :
Spearman correlation coefficients among quantitative variables.

Table 4 :
Association of participant characteristics with the type of therapy performed (reference category: Therapy I).

Table 5 :
Association of participant characteristics with treatment time (reference category: up to 6 months).

Table 6 :
Descriptive analysis of treatment duration according to the therapy adopted.