This study was designed to confirm the clinical efficacy of an alternative method of conservative treatments for TMJ closed lock in adolescents and young adults. We innovatively combined mandibular condylar movement exercise with auriculotemporal nerve block and dextrose prolotherapy to improve curative effects. The technique is unique, to the best of our knowledge, in that TMJ closed lock reduction and reinforced articular disc repositioning could be accomplished in one conservative treatment. The therapeutic process is greatly simplified and shortened.
As the recommendations of the International RDC/TMD Consortium Network (2014), the episode of TMJ “closed lock” has good diagnostic validity for the disc displacement without reduction with limited opening (ie, sensitivity 80%; specificity 97%). [25] Distinct combination of symptoms could be observed in these patients: previous clicking of the TMJ; limitation of mouth-opening immediately after the joint had stopped clicking; oro-facial pain at rest and at mastication; limitation of lateral movement away from the affected side; and deviation of the mandible to the affected side on opening the mouth. [3] In this study, the symptoms combination has been used as strict inclusion criteria. The enrolled patients all have the typical indications for acute TMJ closed lock. A relief of more severe symptoms can be more persuasive evidence for the curative effects of the treatment. And patients’ willingness to accept therapies that can achieve rapid results are fairly strong.
Lei J, et al reported that the prevalence of degenerative TMJ changes could be up to 59.30% in chinses adolescents and young adults with recent-onset disc displacement without reduction. [9] Most of these degenerative changes were early-stage osteoarthritic (OA) changes, including loss of continuity of the articular cortex and surface erosion or destruction identified by high-resolution CBCT. Late-stage OA changes (deviation in form and osteophyte) occurred in 13.63% of the symptomatic TMJs. This is basically consistent with the findings of this study, where 20% (8/40) of the DDwoR patients also presented with degenerative joint disease. Adolescents and young adults may be particularly vulnerable to consequences of degenerative joint disease since normal condylar formation could be hindered. [26] Early diagnosis and intervention is thus prudent to improve the possibility of condylar repair and regeneration to restore TMJ form/structure in adolescents/young adults. [27]
TMJ closed lock start from “mechanical” joint disorder, in which a displaced disc obstructs the forward condylar translation resulting in restricted mouth opening. [3] Theoretically, mandibular condylar movement exercise could overcome the interference of displaced discs and increase condylar mobility. However, patients’ attempts to increase mouth-opening were frequently hindered by the pain of TMJ. Without enough exercise range, the mandibular condylar movement might displace the disc gradually farther forward to an anterior position. Then the increased mouth opening would be a result of adaptive condylar movement over deformed disc. [17] In fact, a number of studies have reported that disc recapturing by regular exercise is very limited. In more than 75% of the successfully treated cases, discs are still anteriorly displaced and deformed. [13, 28] The betterment of function based on adaptive disc deformity is not a stable condition. There are risks of progression to the more advanced stages by a breakdown in the balance between a patient’s adaptive capacity and overloading of the TMJ. Temporomandibular dysfunction might become a recurrent or persistent condition for a long time. [4–7]
Anesthetic block of auriculotemporal nerve can effectively numb TMJ and reduce protective muscle splinting. [21, 22] Subsequently, patients can quickly increase the range of jaw movement through pain-free exercise in several minutes. Meanwhile, sufficient condylar movement produces enough stretching forces on the displaced disc to exceed the anchoring forces produced by vacuum effect, and result in full reduction of the disc. The presence of an audible TMJ click during mandibular condylar movement exercise has been reported by patients in this study, and has been proved an indication for successful TMJ closed-lock reduction. [26, 29] Physical disc reduction in the early course of closed lock is important, because the disc position is not likely to change in long-standing internal derangement. [2–4] Also, an ideal disc‐condyle relationship appears extremely important for condylar repair and regeneration in adolescence or young patients with TMJ DJD. [26]
When the disc is recaptured through excise therapy, a considerable number of cases will be re-dislocated. [14, 26] We designed hypertonic dextrose prolotherapy to stabilize the repositioning of the disc. Fouda, A.A. has reported that injection of hypertonic dextrose in retro-discal area is effective for reducing clicking and subsequently improving TMJ derangement. [23] Dextrose is considered to be the safest proliferating agent as it is soluble in water, a normal constituent of blood chemistry, and can be injected in large quantities without complications. Hypertonic dextrose solutions at the injection site dehydrate cells, which leads to inflammation of local tissue that in turn triggers the release of growth factors such as fibroblast growth factor, and connective tissue growth factor. [30, 31] The growth factors initiate fibroblast proliferation with production of stronger, thicker, and organized connective tissue. [32, 33] Tissue repair can be evident at 2 weeks with fibrosis and other signs of regeneration at the injection sites. [34] Strengthening of ligaments or tendons that compose the posterior band would prevent anterior displacement of articular disc and also result in a tight feeling in posterior area of affected joint, which would spectacularly diminish without further treatments.