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Various nonsurgical interventions have been used for the management of patients with temporomandibular joint (TMJ) disorders, but their clinical effectiveness remains unclear. Hence, the purpose of this systematic review and meta-analyses was to assess the evidence of the effectiveness of nonsurgical interventions in the management of TMJ disorders.
A literature search on five databases such as PubMed, PubMed Central Cochrane, TRIP, NGCH databases and hand searching was conducted for a period from October 1995 to 2015. Randomized control trials (RCTs) on the nonsurgical management of TMJ disorders were included and reported in accordance with Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. The quality of the articles was assessed by JADAD scoring. Finally, out of 23 RCTs, 11 articles having any of the primary outcomes (pain pressure threshold [PPT], pain, maximal pain-free mouth opening, and level of dysfunction) were selected. The extracted data were analyzed using NCSS software.
The results showed the evidence of pain reduction (P = 0.00), maximal pain-free mouth opening (P = 0.0138), and decrease in level of dysfunction (P = 0.0007) but no improvement in PPT to a significant level (P = 0.6600).
Our results suggest that the simplest, cost-effective nonsurgical treatments have a positive therapeutic effect on the initial management of TMJ disorders. However, a consistent methodology recording both the objective and subjective outcomes would be a better choice for added reliability.
The phrase “temporomandibular disorders (TMDs)” is a collective term embracing a number of clinical problems that involve the masticatory musculature, the temporomandibular joint (TMJ) and associated structures, or both.
Due to a poor understanding of the etiology or pathogenesis of TMDs and the lack of definitive diagnostic or therapeutic approaches, patients often have to tolerate the symptoms, including debilitating pain, which substantially impact their quality of life over extended periods of time.
Various interventions have been suggested for TMDs, but to date, the most efficacious/effective approach is still unclear, which may result in a management based more on experience than evidence. The purpose of the current study, therefore, is to investigate the effectiveness of various nonsurgical interventions used in the management of TMDs.
QUORUM guidelines [Appendix 1] were used to design, conduct, and analyze this systematic review and meta-analysis.[INLINE:1]
Aim
The aim of the study was to investigate the effectiveness of various nonsurgical interventions used in the management of TMJ disorders.
Objectives
The objectives of the study were to investigate different nonsurgical therapeutic options for the management of TMDs in terms of pain pressure threshold (PPT), pain, pain-free maximal mouth opening, and level of dysfunction by randomized controlled trials (RCTs).
Search strategy
PubMed, PubMed Central, Cochrane, TRIP, National Guideline Clearing House (NGCH) databases and hand searching of the reference lists of the included studies.
Inclusion criteria
This systematic review and meta-analysis were limited to RCTs for evaluating the efficacy of nonsurgical management of TMDs. All full-text RCTs that evaluated any type of nonsurgical management of TMDs against a placebo or sham or no treatment that were published in any language between October 1990 and 2015 with no previous surgery done in TMJ region.
Exclusion criteria
All other types of studies such as observational, non-RCTs, reviews, articles not indicating the treatment of TMDs, and interventions post-TMJ surgery were excluded from the study.
Data extraction
Full-text copies of all relevant and potentially relevant studies were obtained and assessed independently. All irrelevant records were excluded, and the reasons for their exclusion were noted.
Data analysis
The data analysis was performed using NCSS software (Kaysville, USA) to compare the effects of different interventions.
Outcomes assessed
Main symptoms and the reason for seeking treatment are pain, difficulty in maximum mouth opening, dysfunction in daily activity and reduced pain tolerance. For this reason, these outcomes were selected for determining the relative benefit of the study interventions.
Quality assessment
Each study was evaluated using 5-point JADAD scale
Search
The search strategy identified a total of 7476 records from all databases ([435 – PubMed, 5732 – PubMed Central, 10 – Cochrane, 1217 – TRIP, 60 – NGCH, and hand searching – 22]). Of these, the full texts of 23 potentially eligible papers were retrieved and examined
PRISMA flow diagram.
The systematic review and meta-analysis reviewed 23 full-text RCTs involving 1486 participants. Eleven RCTs in
Assessment of heterogeneity
The clinical and statistical heterogeneities were assessed across the studies before pooling. Clinical heterogeneity was determined by examination of each study's clinical characteristics for any diversity/variation in, for example, technique/delivery of interventions, severity/chronicity of condition, and treatment outcomes. Statistical heterogeneity was assessed by Chi-square test. A significant P < 0.05 for Chi-square test were considered substantial heterogeneity. A test for funnel plot asymmetry to assess publication bias was planned but was not performed because of insufficient numbers of studies pooled in the meta-analyses.
Meta-analysis of studies comparing two means – Pain pressure threshold
Meta-analysis of studies comparing two means - pain pressure threshold.
The studies had proved that PPT can be slightly increased by the use of acupuncture therapy and occlusal splint therapy in 6-month duration for craniomandibular disorder patients,
In the forest plot associated with meta-analysis of combined studies, the mean difference between treatment and control group was found to be 0.074 which was statistically insignificant at P = 0.6600. This confirmed that there was no significant increase of PPT in patients treated with nonsurgical procedures.
Meta-analysis of studies comparing two means – Pain
Five studies compared the various nonsurgical treatment modalities such as acupuncture therapy and occlusal splint therapy, self-relaxation exercises, glucosamine sulfate therapy, gallium-aluminum-arsenide (Ga-Al-As) diode laser therapy, and diclofenac sodium, along with the use of cold/hot packs, soft food diet, and gentle mouth-opening exercise without flat occlusal appliance. Their effectiveness in reducing pain was shown in
Meta-analysis of studies comparing two means - pain.
A study has proved that craniomandibular disorder pain can be reduced by the use of acupuncture and occlusal splint therapy within 6 months.
However, on the contrary, ADDWOR reduction patients did not benefit from taking diclofenac sodium 25 mg along with a flat occlusal appliance during sleeping
The mean difference between treatment and control group using forest plot associated with meta-analysis of combined studies was 0.5098 which was statistically significant at P < 0.001. This implied that the successful outcome of pain reduction occurred in the intervention group than in control group.
Meta-analysis of studies comparing two means – Maximal pain and free mouth opening
Nonsurgical treatment methods such as soft splint, palliative treatment, posture training, glucosamine sulfate 400 mg, ARS with counseling, and diclofenac sodium 25 mg, along with the use of cold/hot packs, soft food diet, gentle mouth-opening exercises, flat occlusal splint, and self-relaxation exercises, are presented in
Meta-analysis of studies comparing two means - maximal pain-free mouth opening.
Soft splints,
However, other nonsurgical treatments using diclofenac sodium 25 mg and instructions for a self-care protocol for ADDWOR,
Forest plot associated with meta-analysis of the studies combined showed the mean difference between treatment and control group as 2.0356 which was statistically significant at P = 0.0138. This confirmed that the successful outcome of increased pain-free maximal mouth opening was in the intervention group than the control group.
Meta-analysis of studies comparing two means – Level of dysfunction
The studies which allowed meta-analysis and data synthesis are presented in
Meta-analysis of studies comparing two means - level of dysfunction.
There is an evidence on the use of occlusal splint therapy to decrease the CDS in craniomandibular disorder patients.
TMJ DDWOR and TMJ capsulitis patients showed an improvement in the level of dysfunction within a week by the use of 0.5 ml of 0.4% dexamethasone sodium phosphate and 1 ml of 4% lidocaine hydrochloride.
On the other hand, ADDWOR cases showed no improvement in dysfunction level on using diclofenac sodium 25 mg, self-care protocol along with a flat occlusal appliance when compared with control group, thus favoring the later.
Using forest plot of meta-analysis of combined studies, the mean difference between treatment and control group was obtained as 0.3855 which was statistically significant at P = 0.007. This proved that the successful outcome of improving the level of dysfunction was in the intervention group than in control group.
Review of nonsurgical management that were not included in meta-analysis
Some of the studies in
While managing cases with TMJ disc displacement, balanced splint, canine-guided splint,
Studies on TMD showed that a single intra-articular injection of sodium hyaluronate offered clear and consistent benefit of markedly lower incidence of relapse along with improvement in objective dysfunction scores for at least 6 months.
A study on myofascial pain with Myofacial pain with limited opening (MLO) proved that, in addition to the natural course of time, brief cognitive behavior intervention promotes faster rate of improvement
Recently, it has been proved in a study that, starting a treatment with occlusal splint associated with an adjuvant nonsteroidal anti-inflammatory for a period of 10 days could be very adequate for a chronic masticatory muscle pain.
Methodological limitations
There are several weaknesses in this review that need to be considered. With any systematic review, the validity of results is based on the ability to include all published reviews, the potential biases, and the quality of the RCTs reviewed.
Despite sincere attempt to include the majority of the published literature in both electronic and manual reviews, some relevant literature might have been missed The recent articles that have got published after the commencement of this review might have been missed. Another factor is that the outcome selected was subjective experience such as pain, PPT, and level of dysfunction which are influenced by the patient's experience and relationship to treatment providers. Furthermore, the measurements and its conversion to a comparable measure may have introduced bias into the meta-analysis Many other outcome measures including range of movements, deviation of jaw, joint noises, and adverse events were not included in many studies. Hence, the comparison of these outcomes was not possible.
From the results of meta-analysis, it can be concluded that nonsurgical treatment methods such as occlusal splints, pharmacological treatments, exercise, posture training, and low-level laser therapy showed evidence of pain improvement, maximal pain-free mouth opening, and a decrease in the level of dysfunction but failed to increase PPT level. Although this review and analysis points to using the simplest, least costly, nonsurgical treatments for the initial or concurrent management of TMDs to achieve a positive therapeutic effect, it is suggested that more studies with consistent methodology should be done for a definitive conclusion of the efficacy of different types of appliances and their comparative effectiveness relative to other common TMD treatments.
Future perspectives
Subgroup analysis and investigation of heterogeneity
If future studies record sufficient explicit data, a subgroup analysis according to age, gender, and the degree of severity of TMDs can be conducted along with the investigation of heterogeneity.
Sensitivity analysis
In future, if there are sufficient trials, following sensitivity analyses to assess the robustness of their review results, this analysis can be repeated after the exclusion of lower quality trials. In addition, sensitivity analyses to examine the effect of allocation concealment, blinded outcome assessment, and completeness of follow-up can be done.
Financial support and sponsorship
Nil.
Conflicts of interest
The authors of this manuscript declare that they have no conflicts of interest, real or perceived, financial or non-financial in this article.