Unilateral Temporomandibular Joint Research Articles

Multidisciplinary treatment of a patient with TMJ ankylosis and a severe dentofacial discrepancy: A case report.

Temporomandibular joint (TMJ) ankylosis is a debilitating condition characterised by the fusion of bony or fibrous tissues in the TMJ, resulting in restricted mouth opening, functional challenges and facial deformities. This report highlights the complexity and multifaceted nature of TMJ ankylosis and emphasises the significance of early intervention and a multidisciplinary approach. Distraction osteogenesis has emerged as a successful method for managing TMJ ankylosis and associated facial asymmetry. Post-distraction orthodontic management is essential to address occlusal changes, including posterior open bite and crossbite. A 17-year-old boy with unilateral right-sided TMJ ankylosis presented with restricted mouth opening, facial asymmetry and functional difficulties. Multidisciplinary treatment planning involved distraction osteogenesis, condylectomy, coronoidectomy and orthodontic correction to achieve proper occlusion and facial aesthetics. The treatment significantly improved facial aesthetics, mouth opening, occlusion and the patient's confidence and self-esteem. This case report underscores the complexity of TMJ ankylosis and the need for a comprehensive approach, including surgical and orthodontic interventions. Collaboration among healthcare professionals and ongoing research is vital to refine treatment approaches and improve the quality of life for patients with TMJ ankylosis.

Mandibular Deviation With Longstanding Temporomandibular Joint Dislocation Caused by Lateral Pterygoid Muscle Hyaline Degeneration.

The present report described a rare case of mandible deviation with longstanding unilateral temporomandibular joint dislocation caused by lateral pterygoid muscle hyaline degeneration. A 28-year-old male was referred for mandible deviation for 2 years. It was found that the left condyle was dislocated just below the articular eminence with the dilated capsule in magnetic resonance imaging images. After surgical dissection of the lateral pterygoid muscle, which was excessively attached to the condyle, the left condyle was reduced, and the patient's mandibular deviation was greatly improved. The pathologic results showed lateral pterygoid muscle hyaline degeneration.

Ultrasound-Guided Vs Non-Guided Prolotherapy for Internal Derangement of Temporomandibular Joint. A Randomized Clinical Trial.

This randomized clinical trial study aims to compare ultrasound-guided versus non-guided Dextrose 10% injections in patients suffering from internal derangement in the temporomandibular joint (TMJ). The study population included 22 patients and 43 TMJs suffering from unilateral or bilateral TMJ painful clicking, magnetic resonance imaging (MRI) proved disc displacement with reduction (DDWR), refractory to or failed conservative treatment. The patients were divided randomly into two groups (non-guided and ultrasound (US)-guided groups). The procedure involved injection of 2 mL solution of a mixture of 0.75 mL 0.9% normal saline solution, 0.3 mL 2% lidocaine and 0.75 mL dextrose 10% using a 25G needle in the joint and 1 mL intramuscular injection to the masseter muscle at the most tender point. The Visual Analogue Score (VAS) was used to compare joint pain intensity over four different periods, beginning with pre-injection, 1-, 2-, and 6-months postinjection. Twenty-two patients 5 males (n = 5/22, 22.7%) and 17 females (n = 17/22, 77.2%) were included in this study. The mean age was 27.3 ± 7.4 years (30.2 ± 7.0) for the non-guided group and 24.3 ± 6.9 for the US-guided group. The dextrose injection reduced intensity over time in both groups with statistically significant improvement (P value <.05) at 2 and 6 months in both groups. There was no statistically significant difference in VAS assessment between both groups. Intra-articular injection of dextrose 10% for patients with painful clicking and DDWR resulted in reduced pain intensity in both US-guided and non-guided groups with significant symptomatic improvement over time in both groups. US guidance allowed accurate anatomical localization and safe procedure with a single joint puncture.

Simultaneous standard total joint prosthesis reconstruction with SSRO and Le Fort I osteotomy in the treatment of unilateral temporomandibular joint ankylosis with jaw deformity: a case cohort study.

Unilateral temporomandibular joint ankylosis with jaw deformity (UTMJAJD) may require simultaneous total joint prosthesis (TJP) reconstruction, sagittal split ramus (SSRO), and Le Fort I osteotomies. The purpose of this study was to evaluate outcomes in patients treated with these procedures. Patients diagnosed UTMJAJD between 2016 and 2018 were selected for the study. Mandible-first procedure was performed after ankylosis release with TJP on the ankylosed side and SSRO on the contralateral side. Le Fort I osteotomy with and without genioplasty was lastly performed. Maximal incisor opening (MIO), facial symmetry, and jaw and condyle stability were compared before, after operation, and during follow-ups. Seven patients were included in the study. Their average chin deviation was 9.5 ± 4.2mm, and maxillary cant was 5.1 ± 3.0°. After operation, jaw deformity significantly improved, with chin deviation corrected 7.6 ± 4.1mm (p = 0.015) and advanced 5.9 ± 2.5mm (p = 0.006). After an average follow-up of 26.6 ± 17.1months, MIO significantly increased from 11.4 ± 9.3 to 35.7 ± 2.6mm (p = 0.000). The occlusion was stable with no significant positional or rotational changes of the jaw (p > 0.05). There was no obvious condylar resorption during follow-ups. Simultaneous TJP reconstruction, SSRO, and Le Fort I osteotomy are reliable and effective methods for the treatment of UTMJAJD.

Effects of orthopedic treatment (distraction splint) on dentofacial deformities in patients with juvenile idiopathic arthritis.

Juvenile idiopathic arthritis (JIA) frequently affects the temporomandibular joint (TMJ), which can alter mandibular growth and development and result in dentofacial deformities. To assess the outcomes of orthopedic treatment with distraction splint (DS) in patients with JIA-related dentofacial deformity. The retrospective study involved 30 patients with JIA and unilateral TMJ involvement, another study group of 20 patients with JIA and bilateral TMJ involvement, and a control group of 18 non-JIA orthodontic patients with Class II and III malocclusions. The inclusion criteria were DS treatment and cone-beam computed tomography (CBCT) scans before (T0) and 2 years after treatment (T1). Dentofacial morphology and deformity were evaluated based on a validated three-dimensional CBCT-based morphometric analysis. Intergroup differences in outcome measures were compared at T0 and T1, and intragroup changes between T0 and T1 were assessed using the Kruskal-Wallis test. Initial evaluations at T0 revealed significant differences between the unilateral and bilateral JIA groups and the control group for three out of eight dentofacial deformity variables: inter-side difference in total posterior mandibular height, mandibular axial angle, and posterior/anterior face height (ratio). At follow-up (T1), significant inter-group differences were only observed in total posterior mandibular height indicating that intergroup differences were less pronounced after splint treatment. Assessing inter-group changes between T0 and T1 showed that all parameters remained constant except posterior/anterior face height ratio, which significantly decreased between T0 and T1. The findings demonstrate the potential of DS treatment for patients with JIA and unilateral or bilateral TMJ involvement to generally support normal dentofacial growth or at least limit further deterioration of dentofacial deformities.

Unilateral temporomandibular joint disorders diagnosed as both disc displacement without reduction and osteoarthritis show vertical craniofacial asymmetry in women

This study investigated the effects of unilateral temporomandibular joint disorders (TMJDs), specifically disc displacement without reduction and osteoarthritis on one side of the temporomandibular joint (TMJ), on facial asymmetry in women, while the contralateral TMJ exhibits normal findings. Participants were retrospectively enrolled and divided into an affected group (n = 42 with unilateral TMJD) and a control group (n = 49 with bilateral healthy TMJs). The affected group was dagnosed with osteoarthritis on cone-bema computed tomograph and anterior disk displacement without reduction on magnetic resonance imaging. The control group showed normal findings bilaterally on both tests. Facial asymmetry was quantified using an asymmetry index derived from posteroanterior cephalograms, comparing both groups. The relationship between TMJD sub-findings and facial asymmetry was also investigated. Significant increases in the asymmetry indexes of the vertical distances from the antegonial notch and gonion to a horizontal reference plane were observed in the affected group (p &lt; 0.05). Additionally, there was a noticeable upward canting of the maxillary, occlusal, and mandibular planes towards the affected side (p &lt; 0.05). Horizontal asymmetry did not differ significantly between groups (p &gt; 0.05). Parafunctional habits in the affected group were correlated with higher asymmetry indexes of the antegonial notch distance (p &lt; 0.05). Women with unilateral TMJD exhibit significantly greater vertical facial asymmetry compared to those without TMJD. These findings may assist clinicians in diagnosing vertical asymmetry in patients with unilateral TMJD using cephalograms and in predicting facial asymmetry progression.

Hybrid total alloplastic temporomandibular joint replacement prosthesis: a pilot study to evaluate feasibility, functional performance and impact on post-operative quality of life.

The aim of the present study was to investigate the clinical efficiency of hybrid alloplastic temporomandibular joint (TMJ) prosthesis in patients undergoing TMJ total alloplastic joint replacement (TMJR). The prosthesis utilized for this study for TMJR is a hybrid variant with combination of stock prototype design and a partial customization of components. A prospective clinical study was conducted involving five patients with unilateral TMJ ankylosis or end-stage joint disease (ESJD) indicated for and requiring TMJR. The patients underwent resection of the joint or gap arthroplasty followed by TMJR using the hybrid alloplastic TMJ prosthesis. The subjective and objective variables that included the jaw function (JF), inter-incisal opening (IO), diet intake (DI) and quality of life (QoL) were assessed using the psychometric modified Likert scale. The nutritional status of the patients was evaluated using the mid-upper arm circumference (MUAC) as reference. The assessed study variables demonstrated functional and observational improvement in the post-operative follow-up when compared to the pre-operative period. The patients showed an improvement in overall QoL and nutritional status post-operatively. The follow-up period showed subjective and objective improvement in the parameters assessed among the study population. There is a technical and clinical feasibility to utilize the hybrid alloplastic TMJ prosthesis as a reliable alloplastic option for treating patients requiring TMJR, with prudent indications.

Binary Logistic Regression Analysis on the Association of Occlusion with the Temporomandibular Joint Arthralgia in the Partial Denture Wearers-A Retrospective Study.

To analyze the potential association between the occlusion features and the incidence of temporomandibular joint (TMJ) arthralgia in patients with partial dentures. A total of 101 partial denture wearers were collected, 45 with unilateral TMJ arthralgia diagnosed according to the Diagnostic Criteria for Temporomandibular Disorders (DC/TMD). Binary logistic regression analysis was adopted. The TMJ asymptomatic group (n = 45) was quantified as 0, while the TMJ arthralgia group (n = 56) was quantified as 1. In total, 13 occlusion variables were analyzed: gender, age, number of prosthetic teeth, number of dentition quadrants with a prosthetic tooth, anterior or posterior prosthesis location in maxillary or mandibular dentition, occluded prosthesis pair, anterior overjet, and overbite relation. Simple and multiple binary logistic models were adopted, accordingly, for the risk impact of them on TMJ arthralgia. Overbite (OR = 2.238) and maxillary anterior prosthesis (OR = 0.305) were entered into the simple binary logistic model; while overbite (OR = 2.774) plus maxillary anterior prosthesis (OR = 0.347), overbite (OR = 3.425) plus unilateral maxillary posterior prosthesis (OR = 4.672), and overbite (OR = 3.476) plus overjet (OR = 0.436) and mandibular anterior prosthesis (OR = 0.177) were entered into the multivariate logistic regression model (all, P < .05). Partial denture wearers with a deep overbite, especially those with a unilateral maxillary posterior prosthesis, had a higher prevalence of unilateral TMJ arthralgia.

Characterization of upper airway and analysis of potential risk factor associated with OSA in patients with unilateral temporomandibular ankylosis and micrognathia deformities

ObjectiveTo ascertain the airway characteristics in patients with unilateral temporomandibular joint ankylosis and maxilla-mandibular deformities (UTMAMD) and investigate the potential risk factors associated with obstructive sleep apnea (OSA) among UTMAMD patients. MethodsAuthors conducted a retrospective single-center study to assess and compare study group consisting of a cohort of 32 patients diagnosed with UTMAMD between January 2011 and July 2022 with control group including 54 participants. The study group was further divided into two subgroups based on the presence or absence of OSA in patients. Parameters related to the upper airway were measured and analyzed using three-dimensional reconstruction of computed tomographic scans. The measurements of airway parameters were compared between study group and control group and between two subgroups. Pearson correlation analysis was used to identify the factors associated with the presence of OSA, and a multiple variable regression model was used to identify risk factors for OSA. ResultsAirway volume (VOL), Minimum cross-section area (min CSA), mean CSA, tilt in sagittal plane (TS), and tilt in sagittal plane (TC) in velopharynx; VOL, airway length (AL), min CSA, mean CSA, TS, TC, and airway deviation (AD) in glossopharynx; min CSA, TS, and AD in hypopharynx were found difference with significance between study group and control group. Lateral dimension/anterior-posterior dimension (LAT/AP) ratio in velopharynx and min CSA, TC, and LAT/AP ratio in glossopharynx were significant different between patients with UTMAMD with OSA and without OSA. ConclusionsThe upper airway of patients with UTMAMD exhibits significant narrowing and distortion, rendering them susceptible to suffer from OSA. Patients with UTMAMD and OSA demonstrate more elliptical airways, and the glossopharyngeal LAT/AP ratio is a predictive indicator for the occurrence of OSA.

Unilateral temporomandibular joint swelling with progressive malocclusion and chin deviation

Unilateral temporomandibular joint swelling with progressive malocclusion and chin deviation

Modified Osteotomy for TMJ Ankylosis in Paediatric Patients with Deficient Interpositional Temporalis Muscle Mass and Buccal Fat Pad - A case Series and Literature Review.

Ankylosis of the temporomandibular joint (TMJ) is a bony or fibrous fusion of the articular surfaces of the mandibular condyle and the glenoid fossa. Gap arthroplasty, Interpositional arthroplasty, Condyle reconstruction with autogenic or alloplastic grafts and total joint replacement are some common modalities of management. In this article, we discuss a series of three cases of unilateral TMJ ankylosis in paediatric patients, managed by gap arthroplasty using a modified osteotomy cut. The modification was adapted due to inadequate interpositionable temporalis muscle or buccal fat on the affected side and chances of adaptive remodelling of the CCG (Costochondral graft), if placed were rendered negative.

The Asymmetry of the Mandible in Patients with Unilateral Temporomandibular Joint Disc Displacement Confirmed by Magnetic Resonance Imaging.

The study aimed to determine the relationship between the mandibular asymmetry index according to Kjellberg between patients with painful unilateral anterior disc displacement (DD) and asymptomatic volunteers without disc displacement. Vertical measurements were performed on a panoramic single-image radiograph, and the disc status was confirmed by magnetic resonance imaging (MRI). Two groups of subjects were retrospectively selected, 40 patients (the overall mean age was 35.5 years; 75% female) with temporomandibular disorder symptoms confirmed by RDC/TMD axis I and manual functional analysis. Unilateral DD was determined by MRI. A comparative group of asymptomatic volunteers (20 dental students with a mean age of 23.4 years; 72% female) had the physiological position of the disc determined by MRI. The vertical asymmetry of the condyle was determined by the method of Kjellberg et al. The symmetry of the gonial angle of the mandible was also measured. A comparison of the mean of the asymmetry index between patients (average 90.89±7.08%) and asymptomatic volunteers (mean 95.86±4.44%) showed a statistically significant difference (p=0.0029). There was no difference (p=0.088) in gonial angle symmetry between the patients (mean 96.48±2.96°) and the asymptomatic volunteers (mean 97.52±2.31°). The distribution of the presence of individual DD diagnoses (partial and total displacement with reduction, displacement without reduction) in patients diagnosed with asymmetry of the mandible was without statistical significance (p>0.05). This study actually points to the asymmetry of the mandible as a potential morphological risk of anterior DD.

Suprafoveal condylar arthroplasty in unilateral disc displacement without reduction – A retrospective study

The aim of this study was to evaluate the efficacy of suprafoveal condylar arthroplasty (SFCA) in the management of patients with unilateral temporomandibular joint (TMJ) disc displacement without reduction (DDWoR). A retrospective study comprising patients who underwent unilateral SFCA for clinically and radiologically confirmed unilateral DDWoR from 2008 to 2020 was conducted. Patients older than 18 years at the time of diagnosis with a minimum of 6 months of unsuccessful non-surgical and minimally invasive management (including diet and life style modification, physiotherapy, appliance therapy, pharmacotherapy, arthrocentesis and arthroscopic lysis and lavage) before undergoing surgery with a minimum of 1 year follow-up post-surgery were included in the study. Patients with other articular and extra-articular causes of restricted mouth opening, prior history of mandibular surgery and/or trauma, growth abnormalities, systemic, metabolic, infective, neoplastic conditions affecting TMJ, including gross occlusal disharmony, untreated existing para-functional habits and bilateral DDWoR, were excluded from the study. Patients were assessed in terms pain on a visual analog scale (VAS), interincisal mouth opening (MO) and subjective assessment of mandibular range of movements including deviation of mouth opening, protrusion and ability for contralateral laterotrusion. 23 patients (10 males and 13 female) were included in the study, with a mean age of 35.09 years and mean follow up period of 37.7 months (range = 12–58; SD = 15.3). The mean pain scores on the VAS reduced from 6.35 preoperatively to 1.13 postoperatively and were found to be statistically significant (p < 0.0001). The improvement of the mean pre-operative mouth opening of 21.83 mm to a mean post-operative mouth opening of 42.09 mm was also found to be statistically significant (p < 0.0001). The subjective improvement in protrusive (p = 0.0003), laterotrusive (p = 0.0005) and opening movements (p = 0.0001) after 1 year were also found to be statistically significant. No patient developed any significant changes in occlusion post-operatively. Four of 23 (17.3%) patients developed transient neuromotor deficit of the temporal branch of the facial nerve. Within the limitations of the study, it seems that SFCA (without addressing the disc) might be an alternative to less invasive treatment approaches, if the latter turned out not to be successful.

The predictive effect of neutrophil-lymphocyte and platelet-lymphocyte ratios in the post-operative recurrence of temporomandibular joint ankylosis.

Reankylosis is a frequent pathology in patients who are operated for post-traumatic temporomandibular joint (TMJ) ankylosis. In the current practice, ankylosing spondylitis attacks are monitored with the increases in neutrophil-lymphocyte ratio (NLR) and platelet-lymphocyte ratio (PLR). In this study, such a relation between TMJ reankylosis and increase in these ratios was evaluated. Patients who were operated between January 2010 and December 2019 for unilateral or bilateral TMJ ankylosis were included in this study. Temporomandibular gap arthroplasty with an interpositional silicone block was performed for each patient by the same operative team. Each patient had standard physiotherapy. All ages and genders were included in the study. Due to the complete blood count differences between children and adults, 18 years of age was used as a cutoff between the groups. A need for reoperation was accepted as reankylosis. The NLR and PLR of children without and with reankylosis and adults without and with reankylosis were compared. Twenty-nine children and 38 adults were included in the study. Mean age of the children and adults were 10.8 and 37.3 years, respectively. Eleven children and eight adults had reankylosis. In patients with reankylosis, NLR and PLR were high significantly, regardless of age. In children, PLR was significantly higher in reankylosis patients. In adults, NLR was significantly higher in reankylosis patients. PLR and NLR may be utilized for predicting reankylosis, respectively, in children and adults who were operated for ankylosis due to TMJ fractures.

Incidental findings involving the temporomandibular joint on computed tomography and magnetic resonance imaging.

The temporomandibular joint (TMJ) is frequently imaged in head and neck computed tomography (CT) and magnetic resonance imaging (MRI) studies. Depending on the indication for the study, an abnormality of the TMJ may be an incidental finding. These findings encompass both intra- and extra-articular disorders. They may also be related to local, regional or systemic conditions. Familiarity with these findings along with pertinent clinical information helps narrow the list of differential diagnoses. While definitive diagnosis may not be immediately apparent, a systematic approach contributes to improved discussions between clinicians and radiologists and better patient management.

Rehabilitation of Dentofacial Asymmetry Secondary to Unilateral Temporomandibular Joint Ankylosis with Dual Distraction and Fixed Orthodontics - Stability at Three-year Follow-up.

Optimal rehabilitation of asymmetric dentofacial deformity secondary to unilateral temporomandibular joint (TMJ) ankylosis is often a challenge. The purpose of this case series is to present an insight into esthetic, occlusal and functional rehabilitation of two patients with varying degree of asymmetric Class II dentofacial deformities secondary to long-standing unilateral TMJ ankylosis. The patients were treated with one-stage surgical protocol employing simultaneous dual distraction technique along with interpositional arthroplasty. Dual distraction technique entailed the simultaneous use of two distractors which allowed for proper control of proximal condylar segment during the course of distraction and lowering the risk of ankylosis recurrence. Thereafter, comprehensive fixed orthodontic mechanotherapy involving the use of temporary anchorage devices was instituted to align and level the compensated dentition. Post-treatment records showed significant improvements in skeletal disharmony and functional stability with good functional occlusion. At the three-year follow-up, the morphological and functionally acceptable results were reasonably well-maintained, with no signs of relapse. Through the two cases reported here, we would like to highlight that one-stage concurrent arthroplasty and dual distraction technique is a safe, stable, and reliable approach for surgical and functional rehabilitation of an adult asymmetric dentofacial deformity secondary to unilateral TMJ ankylosis. Meticulously executed comprehensive orthodontic manipulations involving use of acrylic bite-blocks, elastic traction, and temporary skeletal anchorage device play a crucial role in enhancing the final occlusal outcomes.

Management of unilateral temporomandibular joint ankylosis by interpositional arthroplasty and bilateral coronoidectomy

Management of unilateral temporomandibular joint ankylosis by interpositional arthroplasty and bilateral coronoidectomy

Clinical Evaluation of Intra-Articular Injection of Chondroitin Sulfate and Sodium Hyaluronate in the Management of Degenerative Osteoarthritis of Temporomandibular Joint

AIM: This study aims to evaluate the effectiveness of intra-articular injection of chondroitin sulfate and sodium hyaluronate in cases of temporomandibular joint (TMJ) degenerative osteoarthritis. MATERIAL AND METHODS: Thirty patients ASA I of both sexes, who were selected from outpatient clinic of Oral Surgery Department, Faculty of Dentistry – Suez Canal University, complaining of painful TMJ, presence of unilateral or bilateral TMJ pain, impairment of jaw movements, and joint sounds. Clinical examination was performed to all patients and pre-operative measurements of visual analog scale (VAS) for morning pain, pain with movement and spontaneous pain, maximum mouth opening, and presence or absence of clicking. Patients were randomly divided into two groups; (a) Study group consisted of 15 patients, they had intra-articular injection of chondroitin sulfate and sodium hyaluronate once weekly for 3 weeks and (b) control group consisted of 15 patients, they had intra-articular injection of sodium hyaluronate once weekly for 3 weeks. Post-operative measurements of VAS for previous pain types, maximum mouth opening, and clicking were obtained at 1 month, 3 months, and 6 months post-injection. RESULTS: There was a statistically significant reduction of all types of pain in the study group compared to the control group at all time intervals (p ≤ 0.05), for maximum mouth opening, there was a significant improvement in mouth opening in the study group for all time intervals (p ≤ 0.05), but for the clicking, there was not statistically significant difference between the study and control groups after 1 month, 3 months, and 6 months. The difference between groups was barely statistically significant (p = 0.05). CONCLUSION: Intra-articular injection of a combination of chondroitin sulfate and sodium hyaluronate is an effective tool in reducing pain, clicking, limited mouth opening, and other symptoms associated with degenerative TMJ diseases.

Unilateral disc displacement as a risk factor for development of contralateral disc displacement

<h3>Objective</h3> The aim of this study was to investigate whether unilateral temporomandibular joint disorders (TMD) are associated with increased risk of contralateral TMD development. <h3>Study Design</h3> In total, 401 subjects with and without TMD completed baseline and follow-up MRI and CT imaging 8 years apart on average. Consensus diagnoses of disc displacement (DD) and degenerative joint disease (DJD), made by radiologists who performed the image analyses, were extracted from records. At baseline, 75 subjects had unilateral DD and/or DJD. Fifty-six subjects had bilateral normal joints, forming the control group. Generalized estimating equations were used to account for correlation between joints within a subject and control for age and sex. Odds ratios and 95% confidence intervals were calculated to compare odds of developing DD or DJD in baseline normal joints. <h3>Results</h3> The odds of developing DD were 1.9 times higher in normal joints of those with unilateral DD, with or without DJD, than in those of controls (p=0.14). The odds of DD development among those with unilateral DD and DJD were 3.2 times higher than controls (p=0.049). Among those with baseline unilateral DD, the odds of developing contralateral DD were 7.32 times higher for those without reduction than with reduction (p=0.02). There was no evidence that unilateral DD is associated with contralateral DJD development or vice versa. Additionally, there was no evidence that unilateral DJD is associated with contralateral DJD development regardless of severity. The odds of developing contralateral DD or DJD were not associated with diagnostic progression or improvement of joints with baseline unilateral DJD. However, contralateral DD development was 88% less likely in those with improvement of unilateral DD (p=0.09). <h3>Conclusion</h3> There is some evidence supporting unilateral DD as a risk factor for development of contralateral DD. There is no evidence supporting DJD as a risk factor for development of contralateral DD or DJD. <b>Statement of Ethical Review</b> Ethical Review or exemption was not warranted for this study

The effects of botulinum toxin A injection on the lateral pterygoid muscle in patients with a painful temporomandibular joint click: a randomized clinical trial study

BackgroundTemporomandibular disorder (TMD) is the main cause of non-dental pain in orofacial area. The most common symptoms of TMD are joint pain, joint sound and limitation of jaw function. Botulinum toxin (BTX) injection is considered a potential treatment for TMD due to its pain-relieving properties and its ability to reduce muscle activity. Most of the studies are case series and further investigations are required to prove the efficacy of this treatment modality. Thus, in this study, we aimed to investigate the effect of BTX-A injection on the lateral pterygoid (LP) muscle and to evaluate its efficacy regarding TMD.Materials and methodsThirty-eight patients (19 women and 19 men; mean age of 26.53 years) with painful unilateral temporomandibular joint click and LP muscle tenderness were enrolled in this study. They were divided into two groups; one received an extraoral BTX-A injection in the LP muscle, and the other received a placebo injection. Pain severity, jaw movements, click severity, and Helkimo index were recorded at the first visit, as well as one week, one month, and three months after the intervention. Data were analyzed using repeated-measures analysis of variance and t-tests.ResultsThe results showed that click severity was not significantly different between the BTX-A and placebo groups (P = 0.07). Pain and Helkimo index decreased significantly in the BTX group (P = 0.00 and P = 0.006, respectively); however, there was no significant difference between the two groups (P = 0.22 and P = 1, respectively). There was a significant difference in lateral movements between the groups (P = 0.00) but not in protrusive movement (P = 0.095).ConclusionsIt can be concluded that although some studies have stated that BTX injection can make the click sound disappear, in this study, we did not find a significant difference between the two groups. Furthermore, our results showed that click and pain severity decreased, but the difference was not statistically significant. Therefore, further studies with a higher dosage of BTX and more participants are recommended.Trial registration The local Ethics Committee of Shiraz University of Medical Sciences approved this research (IR.SUMS.REC. 01/10/2018 and IRCT20130521013406N3).