Effect of poly-L-lactic acid and polydioxanone biostimulators on type I and III collagen biosynthesis.

OBJECTIVE: Safe, effective, and biocompatible minimally invasive procedures with the potential to stimulate collagen production have been made to recover dermal thickness and skin quality. The main of this animal model experiment was to observe the effect of poly-L-lactic acid (PLLA) and polydioxanone (PDO) biostimulators in collagen I and III after hypodermal injection. METHODOLOGY: Sixteen adult female rats (Wistar) were randomized into four groups and had dorsal treatment with: G1: hypodermic subcision (HS) only; G2: HS and PLLA hypodermic injection (HI), G3: HS and PDO HI; G4: Control, with no treatment. RESULTS: In histochemical, it was observed hypodermal and dermal tissue in more organized thickness in G3 and in G4 when compared to G1 and G2. There was few difference in G1 compared to G4. The tissue of G2 showed irregularities in the arrangement of collagen fibers, less defined structure and lower distribution of type I collagen compared to the other groups. There is a greater tendency for the proportions of type III collagen among tissues treated with both biostimulators (G2 and G3). PLLA and PDO had relatively similar percentages of collagen when compared to G4. The amount of type I collagen was higher in tissues treated with subcision, while type III collagen was higher in tissues treated with both biostimulators. CONCLUSION: G3 showed better performance in collagen production, although small, when compared with G2.

Histomorphometric Changes of the Masseter Muscle of Rats After a Single Injection of Botulinum Toxin Type A.

BACKGROUND: It has been reported that botulinum toxin type A (BoNT-A) produces structural changes in masticatory muscles. However, not all histomorphometric parameters affected by BoNT-A parameters have been assessed. This study investigated the histomorphometric changes in the masseter muscle of rats after a single injection of BoNT-A. METHODS: Forty-four adult animals were randomly divided into control group (n = 22) and BoNT-A group (n = 22). Controls received a single dose of 0.14 mL/kg of saline in masseter muscles, and the BoNT-A group received a 7 U/Kg of BoNT-A. The groups received the same volume of injected substances. Animals were sacrificed on 7th (n = 5), 14th (n = 5), 21st (n = 5), 28th (n = 4) and 90th (n = 3) days post-treatment. Histological masseter tissue slides were obtained from hematoxylin-eosin treatment and analyzed in optical microscopy regarding muscle cross-sectional area, amount of connective tissue and quantity and diameter of myocytes. For statistical analysis, generalized linear models were used to compare the data (ANOVA). In all test, the significance level of 5% was set. RESULTS: BoNT-A values of cross-sectional area of the masseter muscle were significantly lower than controls (p < 0.01) throughout the study. Regarding myocytes quantity, BoNT-A subgroups presented higher values than controls (p < 0.0001) since the 14th day until the end of the study; however, the diameter of myocytes was smaller in all BoNT-A subgroups (p < 0.0001) in all assessment points. The amount of connective tissue was higher in BoNT-A subgroups (p < 0.0001) throughout the study. CONCLUSION: A single injection of BoNT-A altered the structure of masseter muscle of rats, regarding its histomorphometric parameters. NO LEVEL ASSIGNED: This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

The Role of Prosthesis Spacer for Ocular Prostheses.

Eye defects can lead to emotional, psychological, and social changes, impacting negatively the quality of life of the patient. When these structures cannot be satisfactorily repaired by reconstructive surgery, the prosthetic rehabilitation is the better treatment option to restore lost ocular anatomy and promote the social integration of the individual. The aim of this clinical report is to report and discuss a case of ocular prosthesis confection eviscerated patient with opening limitation eyelid and shortening of the distance between palpebral commissure, to obtain a more natural and comfortable to the patient ocular rehabilitation.

Sleep quality and facial pain in fibromyalgia syndrome.

AIMS: This study aims to evaluate the sleep conditions in fibromyalgia syndrome and the influence of the temporomandibular disorders (TMDs) and fibromyalgia association in self-reported sleep quality. METHODOLOGY: Forty female patients with fibromyalgia (FMS) were compared with 40 healthy women [control group (CG)]. Three questionnaires were used (i.e. RDC/TMD to diagnose TMD and to determine pain intensity and disability and Pittsburgh Sleep Quality Index (PSQI) and Epworth Sleepiness Scale (ESS) to assess sleep conditions). Statistical analyses were performed using the Wilcoxon-Mann-Whitney test to ordinal variables, Student's t-test to obtain the quantitative total scores of PSQI and chronic pain classification, Spearman's rho to determine the correlation between facial pain and quality sleep, and Fisher's exact test for other variables. RESULTS: A moderate correlation between facial pain intensity and low sleep quality was found (rho = 0·56; P<0·0001); however, TMD and FMS association did not show worse sleep quality (P>0·05). Excessive daytime sleepiness was more prevalent in FMS (37·5%; P<0·0001) besides having the worst sleep quality (PSQI = 12·72) compared with CG (PSQI = 4·62). CONCLUSION: Fibromyalgia patients experience intense facial pain in addition to poor sleep and high disabilities. TMD and FMS association do not appear to worsen this condition; however, facial pain intensity was correlated with low sleep quality.

Oral Appliance for the Treatment of Severe Obstructive Sleep Apnea in Edentulous Patient.

Oral appliances have attracted interest for the treatment of mild and moderate obstructive sleep apnea (OSA) and the mandibular repositioning device (MRD) or a tongue-retainer device (TRD) is usually indicated to increase the upper air space. Describes a combination of MRD (with 60 % maximum mandibular protrusion) and TRD to treat severe OSA. Polysomnography (PSG) and two questionnaires: the Epworth Sleepiness Scale (ESS) and the Pittsburgh Sleep Quality Index (PSQI) evaluated the sleep pattern in two times (after and before the use of oral appliance). The initial PSG exam was compatible with diagnoses severe OSA and the Apnea-Hypopnea Index was 40.4, and 54 % oxygen saturation -spO(2). The ESS and PSQI scores were 11 and 6, respectively. After she began wearing the device she stopped snoring, her Apnea-Hypopnea Index decreased to 17.6, presented a sleep efficiency of 81.6 % and had a 77 % spO(2). The ESS and PSQI scores dropped to three. MRD in association with the tongue-retainer was effective in reducing the severity of the apnea for this edentulous patient.

Influence of botulinum toxin A in pain perception and condyle-fossa relationship after the management of temporomandibular dysfunction: a randomized controlled clinical trial.

OBJECTIVES: To investigate the pain perception (PP) and condyle-fossa relationship (CFR) after botulinum toxin A (BoNTA) injection in the masseter muscles of painful muscular temporomandibular dysfunction (TMD) patients. MATERIALS AND METHODS: Fourteen women (aged 29.7 ± 5.4 years) diagnosed with myogenic TMD were randomized in the BoNTA-treated group (TG) and control group (CG). TG masseter muscles (n = 7) were bilaterally injected with 30 U. The CG (n = 7) were injected with saline injections. Condyle-fossa relationship (CFR) spaces were measured in sagittal (SP) and frontal planes (FP) of images of cone-beam computed tomography (CBCT) done before (T0) and after 30 days' interventions (T1). Visual analogue scale (VAS) measured the patients' TMD pain perception (PP). Data were compared by generalized linear models considering the results over time (α = .05). RESULTS: There were no statistical differences in CFR in the SP or FP for TG and CG over time (p ˃ .05), except for frontal lateral space CFR (p < .05). In both groups, the condyle was positioned medially after interventions. Frontal lateral space increased in TG for both, left and right sides, over time (p < .05), as well as PP decreased over time (p < .05) for TG and CG. CONCLUSIONS: The results depicted that there was no significant association with BoNTA injection in TMD masseter muscles in PP and CFR, except considering the frontal lateral space of CFR. CLINICAL RELEVANCE: BoNTA injection in the masseter muscles may not promote clinically significant shifts in the condyle-fossa relationships of muscular TMD patients.

Features of temporomandibular disorders in fibromyalgia syndrome.

This study aimed to investigate the prevalence of clinical features of temporomandibular disorders (TMD) in patients with fibromyalgia. The test group (FMG) consisted of 40 women with fibromyalgia (FM) compared to the control group of 40 healthy subjects using the research diagnostic criteria for temporomandibular disorders (RDC/TMD). The variables were compared using Fisher's exact test and a Mann-Whitney test. Facial pain was reported by 85% of the FM group, and 77.5% were diagnosed with myofascial TMD. Muscle pain during jaw movements, daytime bruxism/clenching, and limited mouth opening were significantly higher in the test group. There was no difference between groups in: (1) joint noises; (2) sleep bruxism/clenching; and (3) excursive or non-excursive movements. Classic signs of TMD, such as joint noise and self-reporting of clenching at night, are not associated with fibromyalgia syndrome as demonstrated in the current study. However, the self-reported daytime parafunctions, muscle pain in jaw movements, and limited mouth opening are features of the patients in the current study. This study revealed specific muscle involvement of TMD is also presence in FM.

Efficacy of Botulinum Toxin Type-A I in the Improvement of Mandibular Motion and Muscle Sensibility in Myofascial Pain TMD Subjects: A Randomized Controlled Trial.

This study assessed the effects of botulinum toxin type A (BoNT-A) in mandibular range of motion and muscle tenderness to palpation in persistent myofascial pain (MFP) patients (ReBEC RBR-2d4vvv). Eighty consecutive female subjects with persistent MFP, were randomly divided into four groups (n = 20): three BoNT-A groups with different doses and a saline solution group (placebo control group). Treatments were injected bilaterally in the masseter and anterior temporalis muscle in a single session. Clinical measurements of mandibular movements included: pain-free opening, maximum unassisted and assisted opening, and right and left lateral excursions. Palpation tests were performed bilaterally in the masseter and temporalis muscle. Follow-up occurred 28 and 180 days after treatment. For the statistical analysis the Mann-Whitney U-test with Bonferroni correction was used for groups comparisons. Regardless of dose, all parameters of mandibular range of motion significantly improved after 180 days in all BoNT-A groups, compared with the control group. Palpation pain over the masseter and temporalis muscles were significantly reduced in all BoNT-A groups regardless of dose, compared with the control group, after 28 and 180 days of treatment. Independent of doses, BoNT-A improved mandibular range of motion and muscle tenderness to palpation in persistent MFP patients.

Long-Term Effects of a Single Application of Botulinum Toxin Type A in Temporomandibular Myofascial Pain Patients: A Controlled Clinical Trial.

This study assessed the long-term effects of botulinum toxin type A (BoNT-A) in subjective pain, pain sensibility, and muscle thickness in persistent myofascial temporomandibular-disorder pain (MFP-TMD) patients. Fourteen female subjects with persistent MFP received BoNT-A treatment with different doses (10U-25U for temporalis muscle and 30U-75U for masseter muscle). The treatment was injected bilaterally in the masseter and anterior temporalis muscles in a single session. Clinical measurements included: self-perceived pain (VAS), pain sensibility (PPT), and muscles thickness (ultrasonography). Follow-up occurred 1, 3, 6, and 72 months after treatment for VAS and PPT and 1, 3, and 72 months for ultrasonography. For statistical analysis, the Friedman test with the Bonferroni test for multiple comparisons as a post hoc test was used for non-parametric repeated measures comparisons among the evaluation times. A 5% probability level was considered significant in all tests. VAS values presented a significant decrease throughout the study (p < 0.05). Regarding PPT values, a significant increase was found when comparing baseline data with post-treatment follow-ups (p < 0.05), and even though a significant decrease was found in muscle thickness when baseline values were compared with the 1- and 3-months assessments, no differences were found when compared with the 72 months follow-up (p > 0.05). A single injection of BoNT-A presents long-term effects in reducing pain in persistent MFP-TMD patients, and a reversibility of adverse effects on masticatory-muscle thickness.

Botulinum toxin type A and acupuncture for masticatory myofascial pain: a randomized clinical trial.

BACKGROUND: BoNT-A has been widely used for TMD therapy. However, the potential benefits compared to dry needling techniques are not clear. OBJECTIVE: this study aimed to compare the immediate effects of botulinum toxin type A (BoNT-A) injections and Acupuncture in myofascial temporomandibular disorders (TMD) patients. METHODOLOGY: 54 women were divided into three groups (n=18). AC patients received four sessions of traditional acupuncture, being one session/week during 20-min. BoNT-A patients were bilaterally injected with 30U and 10U in masseter and anterior temporal muscles, respectively. Moreover, a control group received saline solution (SS) in the same muscles. Self-perceived pain was assessed by visual analog scale, while pressure pain threshold (PPT) was verified by a digital algometer. Electromyographic evaluations (EMG) of anterior temporal and masseter muscles were also measured. All variables were assessed before and 1-month after therapies. The mixed-design two-way repeated measures ANOVA and Tukey's post-hoc tests were used for analysis, considering a=0.05. RESULTS: Self-perceived pain decreased in all groups after one month of therapy (P<.001). BoNT-A was not better than AC in pain reduction (P=0.05), but both therapies were more effective in reducing pain than SS (P<0.05). BoNT-A was the only treatment able to improve PPT values (P<0.05); however, a severe decrease of EMG activity was also found in this group, which is considered an adverse effect. CONCLUSION: after one month of follow-up, all therapies reduced the self-perceived pain in myofascial TMD patients, but only BoNT-A enhanced PPT yet decreased EMG.

Effects of Botulinum Toxin Type A on the Psychosocial Features of Myofascial Pain TMD Subjects: A Randomized Controlled Trial.

AIMS: To determine the effects of botulinum toxin type A (BoNT-A) on the psychosocial features of patients with masticatory myofascial pain (MFP). METHODS: A total of 100 female subjects diagnosed with MFP were randomly assigned into five groups (n = 20 each): oral appliance (OA); saline solution (SS); and three groups with different doses of BoNT-A. Chronic pain-related disability and depressive and somatic symptoms were evaluated with the Research Diagnostic Criteria for Temporomandibular Disorders (RDC/TMD) Axis II instruments at baseline and after 6 months of treatment. Differences in treatment effects within and between groups were compared using chi-square test, and Characteristic Pain Intensity (CPI) was compared using two-way ANOVA. A 5% probability level was considered significant in all tests. RESULTS: Most patients presented low pain-related disability (58%), and 6% presented severely limiting, high pain-related disability. Severe depressive and somatic symptoms were found in 61% and 65% of patients, respectively. In the within-group comparison, BoNT-A and OA significantly improved (P < .001) scores of pain-related disability and depressive and somatic symptoms after 6 months. Only the scores for pain-related disability changed significantly over time in the SS group. In the between-group comparison, BoNT-A and OA significantly improved (P < .05) scores of all variables at the final follow-up when compared to the SS group. No significant difference was found between the BoNT-A and OA groups (P > .05) for all assessed variables over time. CONCLUSION: BoNT-A was at least as effective as OA in improving pain-related disability and depressive and somatic symptoms in patients with masticatory MFP.

Effects of Sandblasting and Hydrofluoric Acid Etching on Surface Topography, Flexural Strength, Modulus and Bond Strength of Composite Cement to Ceramics.

PURPOSE: To evaluate the influence of different surface treatments of two CAD/CAM glass ceramics on surface topography, shear bond strength of composite cement, flexural strength, and elastic modulus. MATERIALS AND METHODS: Two ceramics were evaluated: lithium-disilicate (LDS) and zirconia-reinforced lithium silicate (ZLS) glass ceramics. Glass ceramics were sintered and the surfaces were sandblasted (SBL) or etched with 9% hydrofluoric acid for 10 s (HF10), 20 s (HF20) or 30 s (HF30). The treated surfaces were analyzed using scanning electron microscopy (n = 3) to evaluate the etching pattern. For bond strength testing, ceramic samples were silanized after treatments and an adhesive was applied to the surface. Afterwards, a silicone mold was used to build composite-cement cylinders, which were tested after 24 h or one year of water storage (n = 10). Flexural strength and modulus were assessed using a 3-point bending test (n = 15). The data were subjected to statistical analysis at a pre-set α = 0.05. RESULTS: SBL and HF resulted in different surface topographies. Increased HF etching time influenced the surface dissolution level and exposition of crystals for LDS, while no effect of etching time was observed for ZLS. After one year, the bond strength to LDS significantly decreased, regardless of treatments. For ZLS, HF10 and HF20 showed stable bond strengths over time. SBL yielded the lowest bond strength for both ceramics and statistically significantly reduced the flexural strength of ZLS. The flexural strength and elastic modulus of ceramics were not affected by different etching times. CONCLUSION: Bonding stability depended on the glass ceramic and the pretreatment method employed. HF etching did not change the mechanical properties of the ceramics and is indicated as a ceramic treatment for bonding.

Is low dose of botulinum toxin effective in controlling chronic pain in sleep bruxism, awake bruxism, and temporomandibular disorder?

OBJECTIVE: To evaluate the effects of low doses of botulinum toxin type A (BoNT-A) to control pain in patients with sleep bruxism (SB), awake bruxism (AB), and temporomandibular disorder (TMD) during 180 days. METHODS: Overall sample of thirty-five patients with chronic pain related to TMD, SB, and AB received a single dose of 20 U of BoNT-A in masseter and temporalis muscles. The pain was assessed with a visual analog scale (VAS) before and after 15, 30, 60, 90, and 180 days of the application. RESULTS: The three clinical conditions experienced decrease in pain after 15 days of treatment (p < 0.0001); the maximum pain relief persisted for up to 90 days after BoNT-A application in patients with SB and AB and 15 days for patients with TMD. CONCLUSION: A low dose of BoNT-A may be effective for controlling chronic pain related to SB and AB, but TMD pain reduction was short-lived.

Efficacy and Safety of Botulinum Toxin Type A on Persistent Myofascial Pain: A Randomized Clinical Trial.

This study assessed the safety and efficacy of three different doses of BoNT-A for persistent myofascial pain (MFP). One hundred female subjects were randomly assigned into five groups (n = 20): oral appliance (OA), saline solution (SS) and three BoNT-A groups with different doses. Pain intensity and pressure pain threshold were evaluated up to 24 weeks after treatment. Adverse effects related to muscle contraction, masticatory performance, muscle thickness and mandibular bone volume were also assessed. Changes over time were compared within and between groups. The "nparLD" package and Wilcoxon signed-rank test were used to analyze the data. BoNT-A reduced pain intensity (p < 0.0001) and increased pressure pain threshold (p < 0.0001) for up to 24 weeks compared to the placebo. No differences were found between BoNT-A and OA at the last follow-up. A transient decline in masticatory performance (p < 0.05) and muscle contraction (p < 0.0001), and a decrease in muscle thickness (p < 0.05) and coronoid and condylar process bone volume (p < 0.05) were found as dose-related adverse effects of BoNT-A. Regardless of the dose, BoNT-A was as effective as OA on MFP. Notwithstanding, due to BoNT-A dose-related adverse effects, we suggest the use of low doses of BoNT-A in MFP patients that do not benefit from conservative treatments.

Influence of double flask investing and microwave heating on the superficial porosity, surface roughness, and knoop hardness of acrylic resin.

PURPOSE: Simultaneous polymerization of maxillary and mandibular complete dentures with teeth in occlusion through investing in a double special flask has been described as a more rapid and efficient method to polymerize prostheses than the conventional method; however, no study has been done to verify important properties of resin, including superficial porosity, surface roughness, and hardness, when processed by this technique. The purpose of this study was to verify if the simultaneous polymerization associated with microwave heating may alter the superficial porosity, surface roughness, and Knoop hardness of acrylic resin. MATERIALS AND METHODS: Resin specimens processed in single and double dental flasks were compared using microwave energy and warm water methods. Four groups were tested according to the investing flask and the method of resin cure: Group I control specimens (n = 15) were invested in single metal flasks and cured by warm water at 74 degrees C for 9 hours. Group II (n = 15) specimens were invested in single polyvinyl chloride flasks and cured by microwave energy at 90 W for 20 minutes plus 450 W for 5 minutes. Group III (n = 30) and Group IV (n = 30) specimens were processed by simultaneous polymerization in double flasks and cured by the same warm water and microwave energy protocols, respectively. RESULTS: No significant differences were found in mean superficial porosity (8.06 +/- 2.28 pore/cm(2)), surface roughness (0.14 +/- 0.03 mum), or Knoop hardness (19.66 +/- 2.25 kgf/mm(2)) between the control group (GI), and the other three experimental groups (p > 0.05). CONCLUSION: Processing acrylic resin in a double flask heated by either warm water or microwave energy does not alter the resin's superficial porosity, surface roughness, or Knoop hardness; however, other properties of resin should be analyzed using this denture processing technique.

Distribution of depression, somatization and pain-related impairment in patients with chronic temporomandibular disorders.

OBJECTIVE: the aim of this study was to describe the frequency of psychosocial diagnoses in a large sample of patients attending a tertiary clinic for treatment of temporomandibular disorders (TMD). MATERIAL AND METHODS: six hundred and ninety-one patients who sought treatment for pain-related TMD were selected. Chronic pain-related disability (Graded Chronic Pain Scale, GCPS), depression [Symptoms Checklist-90 (SCL-90) scale for depression, DEP] and somatization levels (SCL-90 scale for non-specific physical symptoms, SOM) were evaluated through the Research Diagnostic Criteria for TMD (RDC/TMD) Axis II psychosocial assessment; TMD diagnoses were based on the Axis I criteria. RESULTS: the majority of patients presented a low disability or no disability at all, with only a small portion of individuals showing a severely limiting, high disability pain-related impairment (4.3%). On the other hand, abnormal scores of depression and somatization were high, with almost half of the individuals having moderate-to-severe levels of depression and three-fourths presenting moderate-to-severe levels of somatization. The prevalence of high pain-related disability (GCPS grades III or IV), severe/moderate depression and somatization was 14.3%, 44% and 74.1% respectively. Gender differences in scores of SCL-DEP (p=0.031) and SCL-SOM (p=0.001) scales were signficant, with females presenting the highest percentage of abnormal values. CONCLUSION: patients with TMD frequently present an emotional profile with low disability, high intensity pain-related impairment, and high to moderate levels of somatization and depression. Therefore, given the importance of psychosocial issues at the prognostic level, it is recommended that clinical trials on TMD treatment include an evaluation of patients' psychosocial profiles.

Prospective study of the aesthetic effect of botulinum toxin a when injected into the muscles of facial expression

Botulinum neurotoxin A (BoNT-A) causes an anticholinergic effect on neuronal fibers, which control muscle contraction and autonomic disorders. Thus, it has been widely used in facial aesthetics, decreasing the action of motor muscles and consequent wrinkles. This preliminary study evaluated the effect of BoNT-A in 77 patients, the treatment satisfaction index was defined in percentage (from 0% to 100%). The evaluation was carried out on 15th, 30th, 60th, 90th, and 180th days after BoNT. The data were analyzed using the Friedman, Student t, Mann-Whitney test with t (alpha=0.05). The results showed that at 15th and 30th days the scores were similar in all muscles with high level of satisfaction and until 90th days the scores decreased significantly for Corrugator supercilii 79.38%, Occipitofrontalis 71.46%, Orbicularis oculi 70.43%; but the satisfaction was good. At 180 days, there was a drop in effectiveness in all treated muscles since the scores decreased significantly, showing low satisfaction by the participants. This study demonstrated that the BoNT-A had attested satisfaction effect by participants for up to 90th days, but at 180th days the satisfaction was low. In the comparative analyzes between women under 40 and over 40 years of age, there was no significant differences.

Botulinum toxin type A and acupuncture for masticatory myofascial pain: a randomized clinical trial

Abstract BoNT-A has been widely used for TMD therapy. However, the potential benefits compared to dry needling techniques are not clear. Objective this study aimed to compare the immediate effects of botulinum toxin type A (BoNT-A) injections and Acupuncture in myofascial temporomandibular disorders (TMD) patients. Methodology 54 women were divided into three groups (n=18). AC patients received four sessions of traditional acupuncture, being one session/week during 20-min. BoNT-A patients were bilaterally injected with 30U and 10U in masseter and anterior temporal muscles, respectively. Moreover, a control group received saline solution (SS) in the same muscles. Self-perceived pain was assessed by visual analog scale, while pressure pain threshold (PPT) was verified by a digital algometer. Electromyographic evaluations (EMG) of anterior temporal and masseter muscles were also measured. All variables were assessed before and 1-month after therapies. The mixed-design two-way repeated measures ANOVA and Tukey's post-hoc tests were used for analysis, considering a=0.05. Results Self-perceived pain decreased in all groups after one month of therapy (P<.001). BoNT-A was not better than AC in pain reduction (P=0.05), but both therapies were more effective in reducing pain than SS (P<0.05). BoNT-A was the only treatment able to improve PPT values (P<0.05); however, a severe decrease of EMG activity was also found in this group, which is considered an adverse effect. Conclusion after one month of follow-up, all therapies reduced the self-perceived pain in myofascial TMD patients, but only BoNT-A enhanced PPT yet decreased EMG.

Chronicity factors of temporomandibular disorders: a critical review of the literature.

Facial pain often persists long after any identifiable organic pathology has healed. Moreover, in a subgroup of patients with temporomandibular disorder (TMD), no treatment is effective. Knowledge of factors associated with persistent pain in TMD could help identify personalized treatment approaches. Therefore, we conducted a critical review of the literature for the period from January 2000 to December 2013 to identify factors related to TMD development and persistence. The literature findings showed that chronic TMD is marked by psychological distress (somatization and depression, affective distress, fear of pain, fear of movement, and catastrophizing) and characteristics of pain amplification (hyperalgesia and allodynia). Furthermore, these factors seem to interact in TMD development. In addition, our review demonstrates that upregulation of the serotonergic pathway, sleep problems, and gene polymorphisms influence the chronicity of TMD. We conclude that psychological distress and pain amplification contribute to chronic TMD development, and that interactions among these factors complicate pain management. These findings emphasize the importance of multidisciplinary assistance in TMD treatment.