Effects of cognitive behavioral therapy on orofacial pain conditions.

Numerous studies have confirmed the effectiveness of cognitive behavioral therapy (CBT) for chronic pain, and it is generally regarded as an appropriate intervention. However, it may not be effective for some pain sites, and the duration of the effect may be limited. In addition, some studies of CBT lacked a comparison group. This review summarizes evidence for the effectiveness of CBT for orofacial pain and assists in the development of guidelines for orofacial pain management. A literature search in PubMed was performed for studies published from April 1990 through March 2020. The search keywords were "burning mouth syndrome," "temporomandibular disorders," "myofascial pain syndrome,""chronic orofacial pain conditions," "cognitive behavioral therapy," and "non-pharmacological therapy." The results indicate that CBT alone or in combination with other treatments, such as intraoral appliance, stress management, or biofeedback, is effective for the vast majority of orofacial pain cases. Therefore, dentists should consider using CBT to manage orofacial pain in their patients.

In search of necessary mouthguard thickness. Part 1: From the viewpoint of shock absorption ability.

PURPOSE: To date, the minimum thickness required for a mouthguard has been assumed to be around 2 mm to 4 mm. However, this figure is based mostly on experience and is yet to be standardized. The purpose of this study is to determine the minimum thickness required to obtain sufficient energy absorption. METHODS: The thicknesses of the tested ethylene vinyl acetate) samples were 1, 2, 3, 4, 5, and 6 mm. The pendulum- type testing equipment used in the present study was also used in a series of earlier studies. Three types of sensors (strain gauge, accelerator, and load cell) and two different impact objects (a steel ball and baseball) were used. RESULTS: The results showed that all the above-mentioned mouthguard thicknesses reduced shocks for all the three types of sensors and both types of impact objects; little difference was observed between sensors and clear results were obtained for the steel ball. An improvement in the energy absorption was observed with an initial increase in the thickness. However, a further increase in the thickness from 4 mm to 5 mm and 6 mm tended to yield a smaller improvement in energy absorption. CONCLUSION: Within the limitations of this study, from the viewpoint of energy absorption ability, the minimum thickness required for a mouthguard is 4 mm, which is generally too large from the viewpoint of player comfort. This finding indicates the necessity of improving the impact absorption ability of mouthguards by considering new designs and developing new materials.

Fluorinated diamond-like carbon as antithrombogenic coating for blood-contacting devices.

Diamond-like carbon (DLC) is being considered for widespread clinical use as a surface coating for cardiovascular devices. We synthesized fluorinated DLC (F-DLC) coatings in order to create a more hydrophobic surface with improved antithrombogenicity and flexibility when compared with conventional DLC coatings by combining the inertness of DLC films with the advantage of fluorination. The purpose of this study was to evaluate the in vitro hemocompatibility and in vivo biocompatibility of the F-DLC coating for medical devices. The in vitro whole blood model confirmed that platelet loss was lower in the F-DLC group than in the noncoated group (SUS316L), which suggests the adhesion of a smaller number of platelets to F-DLC-coated materials. Furthermore, the biomarkers of mechanically induced platelet activation (beta-thromboglobulin) and activated coagulation (thrombin-antithrombin-three complex) were markedly reduced in the F-DLC-coated group. In vivo rat implant model studies revealed no excessive local and systemic inflammatory responses in the F-DLC group. The thickness of the fibrous tissue capsule surrounding the F-DLC-coated disk was almost equal to that of the noncoated SUS316L disk, which has the favorable biocompatibility for metallic implant materials. F-DLC coating thus appears to be a promising candidate for use as a coating material in blood-contacting devices.

Diagnosis of occlusal dysesthesia utilizing prefrontal hemodynamic activity with slight occlusal interference.

Clinical diagnosis of occlusal dysesthesia (OD), also referred to as phantom bite syndrome, is currently based on the absence of objective occlusal discrepancy despite the persistent complaint of uncomfortable bite sensation. We previously demonstrated that the subjective feeling of occlusal discomfort generated by artificial occlusal interference can be objectively evaluated using prefrontal hemodynamic activity in young healthy individuals. The aim of this study was to investigate whether dental patients with and without OD show distinct prefrontal activity during grinding behavior with an occlusal interference. Six dental patients with OD (OD group) and eight patients without OD (control group) grinded piled occlusal strips placed between their first molars and reported their perception and discomfort thresholds during continuous monitoring of prefrontal hemodynamic activity with a portable functional near-infrared spectroscopy. Although patients without OD showed the typical hemodynamic pattern of increased oxyhemoglobin and reduced deoxyhemoglobin (HHb) concentration, those with OD showed persistent incremental increases of HHb concentration that began at the loading of occlusal strips on their molars before they executed grinding. The intensities of the task-related HHb activities showed statistically significant differences between OD and control groups, particularly at channel 3, arranged over the left frontal pole cortex. When the discrimination criterion was set using the intensity values of channel 3 from both groups, the overall accuracy of the OD discrimination was 92.9%. Although physiological interpretation has yet to be elucidated, the task-related response of an increase in HHb may be a useful neuronal signature to characterize dental patients with OD.

Serum Immunoglobulin G Levels to Porphyromonas gingivalis Peptidylarginine Deiminase Affect Clinical Response to Biological Disease-Modifying Antirheumatic Drug in Rheumatoid Arthritis.

OBJECTIVES: To determine whether serum immunity to Porphyromonas gingivalis peptidylarginine deiminase (PPAD) affects the clinical response to biological disease-modifying antirheumatic drug (bDMARD) in patients with rheumatoid arthritis (RA). METHODS: In a retrospective study, rheumatologic and periodontal conditions of 60 patients with RA who had been treated with conventional synthetic DMARD were evaluated before (baseline) and after 3 and 6 months of bDMARD therapy. After serum levels of anti-PPAD immunoglobulin G (IgG) were determined at baseline, the patients were respectively divided into two groups for high and low anti-PPAD IgG titers according to the median measurements. Genotypes at 8 functional single nucleotide polymorphisms (SNPs) related to RA were also determined. RESULTS: After 3 and 6 months of therapy, patients with low anti-PPAD IgG titers showed a significantly greater decrease in changes in the Disease Activity Score including 28 joints using C-reactive protein (DAS28-CRP) (P = 0.04 for both) and anti-cyclic citrullinated peptide (CCP) IgG levels (P = 0.03 and P = 0.04) than patients with high anti-PPAD IgG titers, although these parameter values were comparable at baseline. The anti-PPAD IgG titers were significantly positively correlated with changes in the DAS28-CRP (P = 0.01 for both) and the anti-CCP IgG levels (P = 0.02 for both) from baseline to 3 and 6 months later. A multiple regression analysis revealed a significantly positive association between the anti-PPAD IgG titers and changes in the DAS28-CRP after 6 months of bDMARD therapy (P = 0.006), after adjusting for age, gender, smoking, periodontal condition, and RA-related SNPs. CONCLUSION: The serum IgG levels to PPAD affect the clinical response to bDMARD in patients with RA.

Japan Prosthodontic Society position paper on "occlusal discomfort syndrome".

PURPOSE: Dentists may encounter patients who present with a sense of a malocclusion but in whom no objective findings can be detected. For the patient who insists that there is occlusal discomfort, in the absence of evidence some dentists elect to perform an occlusal adjustment that not only fails to alleviate symptoms, and may, in fact, exacerbate the discomfort. The patient-dentist relationship is then likely compromised because of a lack of trust. STUDY SELECTION: In 2011, the Clinical Practice Guidelines Committee of the Japan Prosthodontic Society formulated guidelines for the management of occlusal discomfort. When formulating clinical practice guidelines, the committee bases their recommendations on information derived from scientific evidence. For "occlusal dysesthesia," however, there are an insufficient number of high-quality papers related to the subject. Therefore, a consensus meeting was convened by the Japan Prosthodontic Society to examine evidence in the Japanese- and English-language literature and generate a multi-center survey to create an appropriate appellation for this condition. RESULTS: As a result of the consensus meeting and survey findings, this condition may be justifiably termed "occlusal discomfort syndrome." CONCLUSIONS: The Japan Prosthodontics Society believes that identification of an umbrella term for occlusal discomfort might serve as a useful guide to formulating clinical practice guidelines in the future. This position paper represents summary findings in the literature combined with the results of a multicenter survey focused on dental occlusal treatment and the condition of patients who present with occlusal discomfort syndrome.

[Questionnaire survey of dentists who made their own mouthguards].

PURPOSE: Most of the mouthguards on the market are inferior in fit and occlusion related to feeling and injury prevention capacity. Therefore, it is necessary to use appropriate custom-made mouth-guards. This research aimed to obtain data for the selection, improvement, and spread of mouthguards in the future. A questionnaire survey of dentists who had made four kinds of mouthguard was conducted in a mouthguard seminar. METHODS: The questionnaire survey concerning "feeling", "difficulty of production", and "selection when considering use and spread" was done for four kinds of mouthguard. The evaluations were made using a ten-point method with the Kruskal-Wallis test and Mann-Whitney U-test. RESULTS: Concerning the feeling: The laminated mouthguard was evaluated the highest, followed in order by improvement type, vacuum, and boil & bite. Concerning the production: The evaluation differed from other questionnaire items. No significant difference was found among all four kinds of mouthguard, so there was no difference in the fabrication difficulty. Concerning the selection and spread: The evaluation was almost the same as for the feeling. The laminated mouthguard was assessed to be the best mouthguard. CONCLUSIONS: The boil & bite mouthguard which is widespread was evaluated the lowest in all items except production. Therefore, it is necessary to encourage players to use an appropriate custom-made type in view of safety, wearing feeling, and dental occlusion.

[Mouthguard effect of tooth distortion during clenching].

PURPOSE: A mouthguard can protect stomatognathic systems from traumatic damage. However, severe occlusal wear of teeth and loss of teeth have often been found in players clinically. These problems might originate in strong clenching during sports. Although it is thought that a mouthguard may be effective for these types of clenching, the relation between mouthguards and clenching has not been sufficiently examined. In this study, the effect of a mouthguard (Drufosoft 3mm, EVA) on tooth distortion caused by clenching was measured and examined at three different clenching strengths. METHODS: As a test tooth, a lower first molar was selected. A strain gauge applied to the outer surface of the buccal cusp was used to measure the distortion. A muscle balance monitor (GC) was used to regulate clenching strengths (10, 50, and 100%). The maximum-effort clenching without a mouthguard was assumed to be the 100% clenching strength. Measurements were conducted with or without mouthguard. A maximum value during clenching was assumed to be date of distortion by using analytical software AcquKnowledge (BIOPAC System Inc.). Statistical analysis software SPSS (SPSS Japan Inc.) was used for the Mann-Whitney test. RESULTS: 1. The tooth distortion by clenching, regardless of the presence of the mouthguard, increased as clenching power strengthened, from 10, 50 to 100%. 2. The tooth distortion, regardless of strength of clenching, was decreased by wearing the mouthguard in all subjects. At 50 and 100% clenching, it was decreased significantly by the mouthguard in all subjects. CONCLUSIONS: Mouthguards decreaseed the tooth distortion caused by clenching. Therefore, a mouthguard may prevent not only traumatic injuries in contact sports but also damage to teeth and periodontal tissues and so on, which occur due to frequent strong clenching in many sports.

Interleukin-6 receptor inhibitor tocilizumab ameliorates periodontal inflammation in patients with rheumatoid arthritis and periodontitis as well as tumor necrosis factor inhibitors.

Interleukin-6 (IL-6) may play a pathological role in rheumatoid arthritis (RA) and periodontitis. Although the efficacy of medication with IL-6 receptor inhibitor, tocilizumab (TCZ), has been demonstrated in the treatment of RA, very little is known about whether TCZ therapy affects periodontitis. The aim of the present study is to compare periodontal condition in patients with RA and periodontitis before and after TCZ therapy. The study participants consisted of 20 patients with RA and periodontitis who were treated with TCZ and 40 patients with RA and periodontitis who received medication with tumor necrosis factor inhibitor (TNFI). Clinical periodontal and rheumatologic assessments and serum biochemical measurements using enzyme-linked immunosorbent assays were performed at baseline and 3 and 6 months later. TCZ and TNFI therapies significantly reduced periodontal inflammation that was determined by gingival index, bleeding on probing, and probing depth (p < 0.017), although plaque levels were comparable before and after the therapies. Both therapies also significantly decreased disease activity score including 28 joints using C-reactive protein (CRP), number of tender and swollen joints, and serum levels of anti-cyclic citrullinated peptide antibodies, rheumatoid factor, CRP, and matrix metalloproteinase-3 (p < 0.017). Additionally, a significant decrease was observed in periodontal clinical attachment level after TCZ therapy (p < 0.017), but not after TNFI therapy. TCZ therapy significantly decreased serum levels of TNF-α, total immunoglobulin G, and serum amyloid A (p < 0.017), although serum levels of IL-6 and soluble IL-6R were significantly increased (p < 0.017). These results suggest a beneficial effect of TCZ therapy on levels of periodontal inflammation in patients with RA and periodontitis, which might be related to decrease in serum inflammatory mediators.

Prefrontal Hemodynamic Changes Associated with Subjective Sense of Occlusal Discomfort.

We used functional near-infrared spectroscopy to measure prefrontal brain activity accompanying the physical sensation of oral discomfort that arose when healthy young-adult volunteers performed a grinding motion with mild occlusal elevation (96 µm). We simultaneously evaluated various forms of occlusal discomfort using the visual analogue scale (VAS) and hemodynamic responses to identify the specific prefrontal activity that occurs with increased occlusal discomfort. The Oxy-Hb responses of selected channels in the bilateral frontopolar and dorsolateral prefrontal cortices increased in participants who reported increased severity of occlusal discomfort, while they decreased in those who reported no change or decreased occlusal discomfort during grinding. Moreover, the cumulative values of Oxy-Hb response in some of these channels were statistically significant predictive factors for the VAS scores. A generalized linear model analysis of Oxy-Hb signals in a group of participants who reported increased discomfort further indicated significant cerebral activation in the right frontopolar and dorsolateral prefrontal cortices that overlapped with the results of correlation analyses. Our results suggest that the increased hemodynamic responses in the prefrontal area reflect the top-down control of attention and/or self-regulation against the uncomfortable somatosensory input, which could be a possible marker to detect the subjective sense of occlusal discomfort.

TRPV4 channel activity is modulated by direct interaction of the ankyrin domain to PI(4,5)P2.

Mutations in the ankyrin repeat domain (ARD) of TRPV4 are responsible for several channelopathies, including Charcot-Marie-Tooth disease type 2C and congenital distal and scapuloperoneal spinal muscular atrophy. However, the molecular pathogenesis mediated by these mutations remains elusive, mainly due to limited understanding of the TRPV4 ARD function. Here we show that phosphoinositide binding to the TRPV4 ARD leads to suppression of the channel activity. Among the phosphoinositides, phosphatidylinositol-4,5-bisphosphate (PI(4,5)P2) most potently binds to the TRPV4 ARD. The crystal structure of the TRPV4 ARD in complex with inositol-1,4,5-trisphosphate, the head-group of PI(4,5)P2, and the molecular-dynamics simulations revealed the PI(4,5)P2-binding amino-acid residues. The TRPV4 channel activities were increased by titration or hydrolysis of membrane PI(4,5)P2. Notably, disease-associated TRPV4 mutations that cause a gain-of-function phenotype abolished PI(4,5)P2 binding and PI(4,5)P2 sensitivity. These findings identify TRPV4 ARD as a lipid-binding domain in which interactions with PI(4,5)P2 normalize the channel activity in TRPV4.

Adhesive strength and its improvement referring to the laminated-type mouthguard.

The manufacture of laminated-type mouthguards requires skill in fusing sheets of mouthguard materials together. Adequate adhesive strength is required to use mouthguards in a stable condition for a long time. Therefore, in this study, the exfoliation test was applied and some treating techniques and conditions that improve the adhesive strength on a laminated surface were examined. Samples were laminated with two pieces of mouthguard material (3 mm thickness) having an adhesive area of 5 x 5 mm2, and whose other end was the holding part. The experimental factors used were as follows: heating time, use of solvent, elimination and direct heating of the laminate surface, colour of materials and water sorption. The result was measured at the time of breakage of the maximum load (N) and the form of destruction was examined. At 165 s of heating time, material failure was shown at under a load exceeding 5.0 N when compared to an untreated condition. Material failure was measured when a solvent was used and during the elimination of the laminated surface at a heating time of 150 s, which is 15 s lesser than in an untreated condition. Material failure was also measured by direct heating on the bonding surface of a second sheet of material at a heating time of 135 s, which is 30 s lesser than in an untreated condition. The differences in colour of the materials influence adhesion. Clear and light coloured materials showed higher adhesion ability. One-way analysis of variance confirmed a statistically significant difference in heating time differences, usage of solvent, elimination, direct heating on bonding surface and colour (P < 0.05). The decrease of adhesive strength by water sorption at 23 degrees and 37 degrees C was not observed significantly. Maximal laminated bond strength can be obtained by minimal heating time and proper treatment with the use of solvent, elimination and direct heating on bonding surface. The differences in the colour of the materials influenced adhesion. Clear and light coloured materials showed higher adhesive ability. Water sorption did not affect the adhesive strength. Therefore, if laminated-type mouthguards were manufactured properly, it can be used for a longer time and in a good condition.

Can mouthguards prevent mandibular bone fractures and concussions? A laboratory study with an artificial skull model.

Some sports' accidents are responsible for inflicting traumatic brain injuries and mandibular bone fractures when impacts occur to the chin. It is often thought that mouth guards can prevent many of these injuries. However, such assertions may be insufficient without adequate research. It is therefore necessary to establish a systematic method of investigation to solve this problem. In the present laboratory study, tests were performed using pendulum impact equipment and an artificial skull model connected to strain gages and accelerometers to simulate and measure the surface distortions related to bone deformation or fractures and the acceleration of the head related to concussions. As impacts, direct blows to the mandibular undersurface were applied. As a result, wearing a mouth guard decreased (P < 0.01) the distortion to the mandibular bone and the acceleration of the head significantly compared with not wearing a mouth guard (54.7%: to the mandible -- measured at a total of three different points, 18.5%: to the head measured at a total of three different points). Within the limits of this study, the following conclusions were drawn: The present measuring system in this study was able to evaluate the distortion to the mandibular and the acceleration of the head from the direct blow to the mandibular undersurface. Mouth guards can reduce distortion to the mandibular and the acceleration of the head from the same blow. So mouth guards might have the possibility to prevent mandibular bone fractures and concussions. However, further well-designed and exhaustive studies are vital to show that mouth guards reduce the incidence of concussions and mandibular bone fractures.

The influence of impact object characteristics on impact force and force absorption by mouthguard material.

Most impact force and impact energy absorption tests for mouthguards have used a steel ball in a drop-ball or the pendulum device. However, in reality most sports-related trauma is caused by objects other than the steel ball, e.g. various sized balls, hockey puck, or bat or stick. Also, the elasticity, the velocity and the mass of the object could change the degree and the extent of injuries. In this study, we attempted to measure the impact force from actual sports equipment in order to clarify the exact mechanism of dental-related sports injuries and the protective effects of mouthguards. The present study was conducted using the pendulum impact device and load cell. Impact objects were removable. Seven mobile impact objects were selected for testing: a steel ball, baseball, softball, field hockey ball, ice hockey puck, cricket ball, and wooden baseball bat. The mouthguard material used in this study was a 3-mm-thick Drufosoft (Dreve-Dentamid GmbH, Unna, Germany), and test samples were made of the one-layer type. The peak transmitted forces without mouthguard ranged from the smallest (ice hockey stick, 46.9 kgf) to the biggest (steel ball, 481.6 kgf). The peak transmitted forces were smaller when the mouthguard was attached than without it for all impact materials but the effect was significantly influenced by the object type. The steel ball showed the biggest (62.1%) absorption ability while the wooden bat showed the second biggest (38.3%). The other balls or the puck showed from 0.6 to 6.0% absorbency. These results show that it is important to test the effectiveness of mouthguards on specific types of sports equipment. In future, we may select different materials and mouthguard designs suitable for specific sports.

The influence of the sensor type on the measured impact absorption of mouthguard material.

Mouthguards have been tested for impact energy absorption using drop-ball and/or pendulum devices. While all reports show efficiency of the mouthguard, the impact absorption abilities reported differ considerably. This difference has been attributed to differences of mouthguard material, design, and the impact force used. However, it is also possibly because of the difference in the sensors used in the experiments. The purpose of this study was to test three types of sensors and to assess which type was most appropriate for measurement of the impact absorption ability of mouthguards. A pendulum-type testing equipment and steel ball, wooden bat, baseball, field-hockey ball were used as the impact object. For all sensors or impact objects, the mouthguard decreased the impact forces. However, the absorption ability of the mouthguard varied according to the sensor or impact object. The absorbency values became smaller with the strain gauge, the accelerometer, and the load cell, respectively. With the steel ball as the impact object, 80.3% of impact absorption was measured with the strain gauge and the accelerometer but, only 62.1% with the load cell sensor. With the wooden bat, impact absorption was 76.3% with the strain gauge and 38.8% for the load cell. For the baseball ball, the absorption measurement decreased from 46.3% with the strain gauge to 4.36 with the load cell and for the field-hockey ball, the decrease in measurement values were similar (23.6% with the strain gauge and 2.43% with the load cell). It is clear that the sensor plays an important role in the measurement values reported for absorbency of mouthguard materials and a standard sensor should be used for all experiments.

Are all mouthguards the same and safe to use? The influence of occlusal supporting mouthguards in decreasing bone distortion and fractures.

The safety benefits of mouthguards have been demonstrated in many studies, with many authors and sports dentists strongly recommending the wearing of mouthguards. However, wearing a mouthguard with incorrect occlusion might cause a variety of problems. It comes as no surprise that a traumatic blow to the chin, while wearing an insufficient mouthguard lacking anterior contact, can result in severe distortions to the mandibular bone, and bone fractures. The aim of this study was to clarify how ineffective insufficient occlusal supporting mouthguards are and how dangerous they can be to use. Consequently, in this study, occlusal supportive areas were varied and accelerations of head and distortions of the mandible were measured using an artificial skull model and a pendulum impact device. As a result, the distortions of the mandible tended to increase as the supported area decreased. On the contrary, accelerations of the head decreased as the occlusion part decreased. Thus, a lot of impact energy was consumed in the distortion of the mandible; accordingly, it seemed that only a little destructive energy was transferred to the head. From this study, it would seem that wearing a mouthguard, which is insufficient in the occlusion, has the potential of causing a bone fracture of the mandible. Consequently, mouthguards should have proper occlusion.