Gonial angle and late implant loss: A retrospective clinical study.

PURPOSE: Occlusal overload can cause late implant loss. However, whether the magnitude of the occlusal force is a risk factor for late implant loss remains unclear. Thus, this clinical study aimed to determine the relationship between the gonial angle (GoA), which is associated with the magnitude of occlusal force, and late implant loss. METHODS: All implants with fixed prostheses placed at the Niigata University Hospital between April 2006 and August 2019 were included in this retrospective study. The implants with and without late loss were compared. Relevant variables, including smoking habits, diabetes mellitus status, remaining dentition, implant length and diameter, prosthesis design, retention systems, splinting, and GoA were assessed. Log-rank test and Cox proportional hazards regression analysis were used to estimate the adjusted hazard ratio (aHR) and to calculate the corresponding 95% confidence intervals (CI) for late implant loss. RESULTS: A total of 919 patients (349 men and 570 women) with 2512 implants were included in this study. Cox proportional hazards regression analysis revealed that a 10° decrease in the GoA (aHR, 1.588; 95% CI, 1.115-1.766; P = 0.010), smoking habits (aHR, 3.909; 95% CI, 2.131-7.168; P < 0.001), and male sex (aHR, 2.584; 95% CI, 1.376-4.850; P = 0.003) were significantly associated with late implant loss. CONCLUSIONS: Within the limitations of this retrospective study of 2512 implants, smaller GoA, smoking habits, and male sex were risk factors for late implant loss.

Marginal bone loss in dental implants: A literature review of risk factors and treatment strategies for prevention.

PURPOSE: Marginal bone loss (MBL) occurs in the periapical cervical bone after dental implant placement and abutment connection. MBL may not result in peri-implantitis; however, it is always accompanied by MBL. Recent studies have demonstrated that early MBL is a predictor of peri-implantitis. In this narrative review, we aimed to provide an evidence base for recommended treatment strategies for clinicians to prevent MBL. STUDY SELECTION: We reviewed the recent literature and performed a narrative synthesis of the evidence, focusing on available systematic reviews and meta-analyses of implant marginal bone resorption. RESULTS: The available evidence indicates that certain biological, material, and technical factors can influence MBL and consequently dictate the risk of developing peri-implant disease in later years. The order of the impact of the strength of each factor is unknown. Current recommendations to prevent MBL include controlling patients' smoking and hemoglobin A1c levels to sufficiently low levels before surgery and throughout their lifetime. Regarding the material, a platform-switching, conical-connecting implant system, and an abutment with a height of at least 2 mm should be selected. Placement should be performed using techniques that ensure sufficient soft tissue (keratinized gingival width > 2 mm, supracrestal tissue height > 3 mm), and non-undersized preparations in the cortical bone should be made with connected concave abutments during primary or secondary surgery. Patients should receive supportive peri-implant therapy during maintenance. CONCLUSIONS: MBL development is multifactorial and can be reduced by considering the biological, material, and technical factors.

Early Mobilization Using a Mobile Patient Lift in the ICU: A Randomized Controlled Trial.

OBJECTIVES: To ascertain whether a mobile patient lift facilitates early mobilization in ventilated ICU patients. DESIGN: A single-center, open-label, randomized controlled trial. SETTING: An academic ICU in Tokyo. PATIENTS: Eighty patients were admitted to ICU and expected ventilation for at least 48 hours. INTERVENTIONS: In the intervention group, in addition to the rehabilitation protocol received by the control group, patients were assisted in sitting, standing, transfers, and walking using the mobile patient lift. MEASUREMENTS AND MAIN RESULTS: The intervention group predominantly stood faster than the control group (1.0 vs. 3.0 d, p < 0.01). The Intervention group also had significantly higher Functional Status Score-ICU scores at ICU discharge. However, the Medical Research Council score and Barthel index at discharge, length of ICU stay, and number of ventilator-free days did not differ between the two groups. CONCLUSIONS: The use of mobile patient lifts facilitates the earlier standing of patients on ventilators. This may contribute to patients improved physical function in the ICU. TRIAL REGISTRATION: The study protocol was registered with the University Hospital Medical Information Network (UMIN) under the registration number UMIN000044965. Registered July 30, 2021.

Actual state of the diurnal masseteric electromyogram: Differences between awareness and non-awareness of awake bruxism.

PURPOSE: This study aimed to elucidate the relationship between diurnal masseter muscle activity and awareness of diurnal awake bruxism (d-AB) by conducting a comparative analysis of electromyographic (EMG) data from individuals with and without awareness of diurnal awake bruxism (d-AB), utilizing EMG data gathered from multiple subjects. METHODS: Unilateral masseter electromyography (EMG) recordings were performed during the daytime using an ultraminiature wearable EMG device. A total of 119 participants (59 with awareness of diurnal tooth clenching [d-TC] and 60 without awareness of d-TC) were included. Waveforms longer than 0.25 s with the two amplitude conditions, exceeding twice the baseline and >5% of maximum voluntary clenching, were extracted. In addition, the number of bursts and episodes (groups of bursts), burst duration, and burst peak amplitude were calculated for each participant. RESULTS: There were no significant differences in the EMG parameters between the groups with and without awareness of d-TC. Additionally, the frequency distribution of the number of EMG waveforms exhibited wide ranges and substantial overlap between the two groups. CONCLUSIONS: The variability in the number of bursts and episodes, burst peak amplitude, and burst duration among subjects suggests the need for an objective classification of d-AB severity based on EMG values. The absence of significant differences and large overlap in frequency distributions between the groups with and without awareness of d-TC indicate difficulty in predicting muscle activity solely based on awareness of d-AB.

Masseter muscle cross-sectional area and late implant failure: A case-control study.

INTRODUCTION: Occlusal overload is considered to be one of the causes of late implant failure. However, it is unclear whether the magnitude of the patient's occlusal force is a risk factor for late implant failure. PURPOSE: This case-control study aimed to clarify the association between the cross-sectional area (CSA) of the masseter muscle and late implant failure. METHODS: This case-control study was limited to implant-supported fixed prostheses. We compared cases with at least one late implant failure (n = 25 patients) to controls (n = 82 patients) without implant failure. Patients were matched by age, sex, year of surgery, jaw and tooth type, and bone graft. Log-rank and Cox proportional hazard regression analyses were used to identify possible risk factors for late implant failure. RESULTS: The incidence of late implant failure was significantly associated with masseter muscle CSA ≥504.5 mm2 (hazard ratio: 4.43; 95% CI: 1.82-10.79; p < 0.01). CONCLUSION: Higher masseter muscle CSA increases the risk of late implant failure.

Early mobilisation using a mobile patient lift in the intensive care unit: protocol for a randomised controlled trial.

INTRODUCTION: It is important to prevent the deterioration of activities of daily living to improve the long-term prognoses of patients in the intensive care unit (ICU). The patients' conditions, along with the lack of human and technical resources, often become barriers to achieving early mobilisation after the introduction of mechanical ventilation. We plan to verify the usefulness of a mobile patient lift for early mobilisation. METHODS AND ANALYSIS: We will conduct a single-centre, open-label, randomised controlled trial. The inclusion criteria are as follows: age ≥18 years, independent walking before admission and expected mechanical ventilation for at least 48 hours. The participants will be randomly divided into groups with (intervention group) or without (control group) a mobile lift protocol. A mobile lift will be used in the intervention group. The primary endpoint will be the number of days required to achieve an ICU mobility scale of ≥4 (standing position). The results of the two groups will be analysed using the Student's t-test. ETHICS AND DISSEMINATION: This study will be conducted in accordance with the Declaration of Helsinki and with the approval of the Toho University Omori Medical Center Ethics Committee (approval number M20259). The results of this study will be presented internationally at academic conferences and published in the literature. TRIAL REGISTRATION NUMBER: UMIN000044965.

Bone heating and implant removal using a high-frequency electrosurgical device: An in vivo experimental study.

OBJECTIVES: Failed implant removal using a high-frequency electrosurgical device (HFED) has been reported to be less invasive than other surgical techniques. We sought to clarify the mechanism of removal torque reduction in an implant by heating with HFED. MATERIALS AND METHODS: Sixty-eight Wistar rats received titanium implants on the maxillary bone 4 weeks after extraction of the first and second molars. The control group was sacrificed 6 weeks after implant installation. In the experimental group, the implant was heated by HFED for 10 s using three different power outputs, and samples were collected at 3, 7, and 14 days after heating. Removal torque measurement and histological analysis were performed in the control and experimental groups. Implant surfaces were observed using an electron-probe microanalyzer (EPMA). Data were analyzed using Mann-Whitney U test at a significance level of 5%. RESULTS: The removal torque could not be measured in the control group due to fracture of the implant. After heating, the removal torque was measurable without fracture and decreased significantly at 14 days as compared with that at 3 days (p < .05). Heating with "min" power output resulted in a significantly smaller blank lacunae area and fewer osteoclasts at 14 days after heating (p < .05). EPMA revealed bone matrix adherence to outer surface of heated implant. CONCLUSIONS: After heating, an enlarged area of blank lacunae around the implant and an increased number of osteoclasts into the bone marrow cavity were observed, which may have contributed to the reduction in removal torque.

Association between time to lithotripsy and stone-free rate in patients with ureteral stones undergoing shock wave lithotripsy.

Early shock wave lithotripsy is associated with higher stone-free rate compared to delayed treatment of ureteral stones, but may constitute overtreatment because ureteral stones can pass spontaneously. We studied the association between time to treatment and stone-free rate in patients with ureteral stones to determine optimal shock wave lithotripsy timing. We retrospectively analyzed 537 patients undergoing shock wave lithotripsy for ureteral stones. Patients were divided into five groups according to time from onset of symptoms to lithotripsy-urgent (0-3 days), early (4-30 days), late (31-60 days), long-delayed lithotripsy (≥ 61 days), and asymptomatic. Stone-free rates were compared among groups. Mean age and stone size were 55.6 ± 13.1 years and 7.48 ± 3.29 mm, respectively. Mean number of shock wave lithotripsy sessions and stone-free rate were 1.37 and 91.6%, respectively, in the overall population. Stone-free rates were 95.2%, 96.8%, 91.3%, 86.3%, and 82.7% in urgent, early, late, long-delayed lithotripsy, and asymptomatic groups, respectively. Long-delayed lithotripsy and asymptomatic groups had significantly more lithotripsy sessions and lower stone-free rate, compared to urgent and early lithotripsy groups. In multivariate analysis, time to lithotripsy [long-delayed lithotripsy (odds ratio: 0.273, p = 0.004) and asymptomatic nature (odds ratio: 0.236, p = 0.002)] and age (odds ratio: 0.959, p = 0.003) independently affected stone-free rate. In conclusion, time to lithotripsy is a strong predictive factor for stone-free status following shock wave lithotripsy. Urgent shock wave lithotripsy did not improve stone-free rate if performed within 1 month. However, time to shock wave lithotripsy > 2 months reduced likelihood of stone-free status.

Reducing bacterial counts around the abutment following professional mechanical plaque removal at the implant bridge: A randomized crossover comparison of removing or not removing the superstructure.

PURPOSE: The purpose of this study was to determine whether removing the superstructure of the implant bridge in cases of full-arch implant restorations for edentulous atrophic arches at the abutment level during professional mechanical plaque removal (PMPR) affects bacterial counts. METHODS: This crossover clinical trial included 20 patients who received screw-retained prostheses at the abutment level. Patients were randomly assigned to two groups and received PMPR with or without removal of the superstructure. After a three-month washout period, the type of treatment was reversed between the groups. Bacterial counts around the cylinder and abutment were measured and compared before and after PMPR. RESULTS: Bacterial numbers around the cylinder and abutment were significantly reduced after PMPR as compared with before PMPR regardless of whether the superstructure was removed (p <0.05). However the ratio of subjects with bacteria at 1.0 × 105 colony forming unit/ml (cfu/ml) or more after PMPR was significantly higher when the superstructure was not removed (p < 0.05). Among patients with bacterial counts of less than 10 × 105 cfu/ml, bacterial loads were reduced to less than 1.0 × 105 cfu/ml even when superstructures were not removed. Among patients with bacterial load of >10 × 105 cfu/ml, bacterial numbers were not reduced to <1.0 × 105 cfu/ml when PMPR was performed without removing the superstructure. CONCLUSIONS: Removal of the superstructure in cases of full-arch implant restorations for edentulous atrophic arches during PMPR reduces bacterial numbers around the implant bridge at the abutment level.

Risks and complications of robot-assisted radical prostatectomy (RARP) in patients receiving antiplatelet and/or anticoagulant therapy: a retrospective cohort study in a single institute.

The objective of the study was to evaluate the risk of bleeding complications in patients undergoing robot-assisted radical prostatectomy (RARP) while taking antiplatelet (AP) and/or anticoagulant (AC) agents. We analyzed the data of 334 patients undergoing RARP from May 2015 to May 2019. Patients were categorized into AP, AC, and control groups; the bleeding complications were compared among them. The end points were the estimated blood loss, decrease in hemoglobin level, and bleeding complications. The patient characteristics did not differ significantly among groups, with the exception of ASA scores, which were significantly higher in the AP and AC groups vs. the control group. The estimated blood loss and hemoglobin decrease were not significantly different between the AP and AC groups and the control group. The frequency of bleeding complications did not differ significantly between the AP and the control groups, but was significantly higher in the AC vs. the control group (4.3% in the AP and 23.5% in the AC group vs. 3.7% in the control group; P = 0.63 and P < 0.01, respectively). There was no significant difference in bleeding complications between the AP continuation (continuation of a single AP) and the AP interruption group or between the heparin bridging and the AC interruption group. All bleeding complications observed in the AC group occurred after resuming AC therapy. RARP can be performed safely with continuation of a single AP, and in patients taking ACs by interrupting these agents or via heparin bridging, without increasing intraoperative bleeding, whereas postoperative bleeding complications may increase after resuming ACs.

Vertical distraction osteogenesis of a reconstructed mandible with a free vascularized fibula flap: a report of two cases.

BACKGROUND: The free vascularized fibula flap presents many advantages such as sufficient length of the bony segment, good vascularization, better quality of the bone, and a long vascular pedicle, but it is also associated with some disadvantages with regard to prosthetic rehabilitation because of its limited height. Improvement in bone height is necessary for ideal dental implant treatment of reconstructed mandibles. CASE PRESENTATION: For two squamous cell carcinoma patients, mandibular bone reconstruction was performed secondarily with the peroneal flap after tumor resection. Since the bone height was insufficient at the time of implant treatment, occlusion reconstruction by dental implant was performed after vertical distraction osteogenesis. CONCLUSIONS: Vertical distraction osteogenesis is a suitable treatment option for alveolar ridge deficiency resulting from fibula transplantation for mandibular reconstruction following tumor surgery.

Risk factors associated with post-loading implant loss of removable and fixed implant-supported prostheses in edentulous jaws.

PURPOSE: This study analyzed risk factors for post-loading implant loss in cases of implant-supported prostheses applied to edentulous jaws of Japanese patients. METHODS: In total, 245 dental implant fixtures placed in 54 edentulous jaws of 46 patients performed at Niigata University Hospital were retrospectively analyzed. Kaplan-Meier curves were used to estimate the cumulative survival rate (SR) of implants, and multiple Cox regression analysis was used to identify predictive factors of implant loss. The following risk factors for implant failure were examined: age, sex, survival time, implant length, implant location, smoking habit, bone density, bone augmentation, opposing dentition, loading period, and type of final restoration. The Cochran-Mantel-Haenszel test was used to examine difference in survival curves of the extracted predictors. RESULTS: Sixteen implants failed during the observation period (SR=92.8 %). Multiple Cox regression analysis revealed that male sex [hazard ratio (HR)=16.1; p=0.007] and use of maxillary removable restorations (HR=12.7; p<0.000) were risk factors for implant failure. Other factors had no significant effect on implant failure. The SR of implants for males (SR=86.9%) was significantly lower than that for females (SR=99.1%). The SR of implants for maxillary removable restorations (SR=76.4%) was significantly lower than for maxillary fixed restorations (SR=99.1%) and mandibular fixed restorations (SR=97.8%). CONCLUSIONS: Maxillary implants with removable restorations and male sex were risk factors for implant failure among Japanese edentulous patients.

Trabecular bone microstructure and mineral density in human residual ridge at various intervals over a long period after tooth extraction.

BACKGROUND: Long-term changes of trabecular microstructure in human tooth extraction socket have not been investigated. PURPOSE: To examine the trabecular microstructure of human residual ridges at various intervals following tooth extraction, and to determine whether bone remodeling activity can attain points of relative stability and when such points are reached. MATERIALS AND METHODS: Forty-four bone biopsy specimens were obtained from lower molar or premolar regions of residual ridges. Postextraction times ranged from 1.6 to 360 months. Samples were analyzed using micro-computed tomography and three-dimensional bone morphometry with histological analyses. Trabecular bone parameters were plotted against postextraction times, and a stepwise piecewise linear regression analysis was performed to determine at which points of time these parameters either increased or decreased. RESULTS: Using piecewise linear regression, "inflection points" were found in most trabecular bone parameters between 7 and 12 months postextraction. Among the residual ridge samples, woven trabecular structure became mature, consisting of thick lamellar trabeculae with sufficient bone density, under dynamic bone remodeling until the 7th to 12th month post-tooth extraction. After this period, the mature network structure remained stable with low remodeling activity. CONCLUSION: Bone remodeling of trabecular structure in human residual ridge after tooth extraction had a stabilization period.

Pneumococcal DNA-binding proteins released through autolysis induce the production of proinflammatory cytokines via toll-like receptor 4.

Streptococcus pneumoniae is a leading cause of bacterial pneumonia. Our previous study suggested that S. pneumoniae autolysis-dependently releases intracellular pneumolysin, which subsequently leads to lung injury. In this study, we hypothesized that pneumococcal autolysis induces the leakage of additional intracellular molecules that could increase the pathogenicity of S. pneumoniae. Liquid chromatography tandem-mass spectrometry analysis identified that chaperone protein DnaK, elongation factor Tu (EF-Tu), and glyceraldehyde-3-phosphate dehydrogenase (GAPDH) were released with pneumococcal DNA by autolysis. We demonstrated that recombinant (r) DnaK, rEF-Tu, and rGAPDH induced significantly higher levels of interleukin-6 and tumor necrosis factor production in peritoneal macrophages and THP-1-derived macrophage-like cells via toll-like receptor 4. Furthermore, the DNA-binding activity of these proteins was confirmed by surface plasmon resonance assay. We demonstrated that pneumococcal DnaK, EF-Tu, and GAPDH induced the production of proinflammatory cytokines in macrophages, and might cause host tissue damage and affect the development of pneumococcal diseases.

Impact of Androgen Deprivation Therapy on Volume Reduction and Lower Urinary Tract Symptoms in Patients with Prostate Cancer.

OBJECTIVE: To evaluate the impact of androgen deprivation therapy (ADT) on prostate volume, lower urinary tract symptoms (LUTS), and LUTS-related quality of life (QOL) in patients with prostate cancer. METHODS: Patients with prostate cancer (PCa) were treated with goserelin and bicalutamide for 24 weeks. Changes in the total prostate volume (TPV), International Prostate Symptom Score (IPSS), and QOL score for urinary symptoms were assessed every 12 weeks. Of the 42 patients enrolled, 8 patients withdrew and 2 were excluded, so 32 patients were analyzed. RESULTS: The median age, PSA levels, and TPV were 77.5 years, 22.0 ng/mL, and 29.5 cm3 , respectively. TPV showed a significant decrease from baseline in weeks 12 and 24, with the mean percent decreases being -37.5 ± 4.25 and -7.5 ± 3.84%, respectively. The IPSS decreased from baseline to weeks 12 and 24 (from 11.7 ± 1.6 to 9.3 ± 1.0 and 9.3 ± 1.0; P = 0.15 and 0.2, respectively). The IPSS voiding score showed a significant decrease from baseline to weeks 12 and 24 whereas the IPSS storage score did not. In patients with moderate to severe LUTS, the IPSS and the QOL score showed a significant decrease in weeks 12 and 24. In patients with mild LUTS, nocturia increased significantly from baseline and there was approximately one additional episode of nocturia at 24 weeks. CONCLUSIONS: In this study, we observed that ADT significantly reduced TPV and improved LUTS in patients with PCa and moderate to severe LUTS, but increased nocturia in patients with mild LUTS.

Risks and complications of transurethral resection of bladder tumors in patients receiving antiplatelet and/or anticoagulant therapy: a retrospective cohort study.

BACKGROUND: Information on the safety of transurethral resection of bladder tumors (TURBT) in patients receiving anti-thromboembolic drugs is currently lacking. This study aimed to evaluate the clinical safety of TURBT in patients receiving anti-thromboembolic agents compared with patients not taking these agents and patients who interrupted their use perioperatively. METHODS: We retrospectively analyzed data for patients who underwent TURBT at Jichi Medical University Saitama Medical Center from September 2013 to August 2016.Patients who underwent surgery while receiving antiplatelet and/or anticoagulant drugs were allocated to the continuation group, those who interrupted these drugs comprised the interruption group, and those who did not use these agents were designated as the control group. We compared the patient characteristics, hemoglobin levels, and complications among the three groups. RESULTS: A total of 174 patients were analyzed including 19, 18, and 137 in the continuation, interruption, and control groups, respectively. There were no significant differences in patient and tumor characteristics, apart from age, among the three groups. Decreases in hemoglobin levels were similar in the continuation, interruption, and control groups (-0.50 g/dl, -0.40 g/dl, and -0.50 g/dl, respectively).Significantly more patients in the continuation group experienced clot retention compared with the control group (21% vs 5%, p = 0.03). Large tumor size tended to be a risk factor for clot retention in the continuation group (p = 0.07). No patient in the continuation or interruption group required blood transfusion, compared with two patients (1%) in the control group. No patients in any of the groups experienced cardiovascular events during their hospital stay or required rehospitalization for hematuria after discharge. CONCLUSIONS: TURBT can be performed safely in patients who continue to take antiplatelet and/or anticoagulant agents, without increasing the risks of severe hemorrhage and blood transfusion. However, the risk of postoperative clot retention may be increased in these patients.

Antimicrobial activity of ethylene-vinyl acetate containing bioactive filler against oral bacteria.

We developed an ethylene vinyl acetate (EVA) containing surface pre-reacted glass-ionomer (S-PRG) filler, as a new mouthguard material for preventing intraoral bacterial infection. We examined its physical properties, antimicrobial activity against a major cariogenic bacterium Streptococcus mutans and a periodontopathogen Porphyromonas gingivalis, and its cytotoxicity toward human gingival epithelial cells. S-PRG filler was added to EVA copolymer at 5, 10, 20, or 40 wt% and was processed into disc-shaped test specimens. Only minor differences between the Shore hardness and rebound resilience properties of EVA materials with and without the S-PRG filler were observed. The specimens with S-PRG filler showed bacteriostatic activity toward S. mutans and P. gingivalis and inhibited S. mutans biofilm formation. No cytotoxicity against the gingival epithelial cells was observed. Our findings show that EVA containing S-PRG filler has antimicrobial activity toward pathogenic oral bacteria and may be an effective material for maintaining the oral health of athletes.

Transperineal ultrasound-guided prostate biopsy is safe even when patients are on combination antiplatelet and/or anticoagulation therapy.

BACKGROUND: To assess whether hemorrhagic complications associated with transperineal prostate biopsy increased in patients on antiplatelet and/or anticoagulant therapy. METHODS: In total, 598 consecutive patients underwent transperineal prostate biopsy. The medication group comprised patients who took anti-thromboembolic agents, and the control group comprised those who did not take these agents. No anti-thromboembolic agent was stopped before, during, or after prostate biopsy in the medication group. Complications developing in both groups were compared and classified using the modified Clavien classification system. Subgroup analyses to compare complications in patients taking single antiplatelet, single anticoagulant, and dual antiplatelet and/or anticoagulant agents, and multivariate analyses to predict bleeding risk were also performed. RESULTS: Of the 598 eligible patients, 149 comprised the medication group and 449 comprised the control group. Hematuria (Grade I) developed in 88 (59.1%) and 236 (52.5%) patients in the medication and control group, respectively (p = 0.18). Clot retention (Grade I) was more frequently observed in the medication group than the controls (2.0% versus 0.2%, respectively, p < 0.05). Hospitalization was more frequently prolonged in the medication than the control group (4.0% versus 0.4% of patients, respectively). No complication of Grade III or higher developed in either group. Hematuria was more frequent in patients taking a single anticoagulant (p = 0.007) or two anti-thromboembolic agents (p = 0.04) compared with those taking a single antiplatelet agent. Other complications were generally similar among the groups. In the multivariate analysis, taking more than two anti-thromboembolic agents was the only significant risk factor for bleeding events. CONCLUSION: No severe complication developed after the transperineal biopsies in either group, although minor bleeding was somewhat more frequent in the medication group. It may not be necessary to discontinue anticoagulant and/or antiplatelet agents when transperineal prostate biopsy is contemplated.

Quantitative evaluation of masseter muscle stiffness in patients with temporomandibular disorders using shear wave elastography.

PURPOSE: The aim of this study was to quantify masseter muscle stiffness in patients with masticatory myofascial pain. METHODS: Stiffness was measured using shear wave elastography, which expresses stiffness as shear wave velocity (Vs). A phantom study was conducted to confirm the reliability of the measuring device. The study participants were 26 females with bilateral masseter muscle pain who were classified into either Research Diagnostic Criteria for Temporomandibular Disorders (RDC/TMD) group Ia (myofascial pain; n=13) or RDC/TMD group Ib (myofascial pain with limited opening; n=13). Healthy controls consisted of 24 female volunteers with normal teeth and jaws, who were not classified into groups I/II/III by RDC/TMD. RESULTS: Muscle stiffness was 1.96m/s (12.5kPa) in 13 patients in group Ia, 2.00m/s (13.0kPa) in 13 patients in group Ib and 1.27m/s (5.25kPa) in 24 control subjects. Vs was significantly greater in groups Ia and Ib than in the control group (p<0.05). Characteristic pain intensity (CPI) became clear as an independent factor impacting Vs (partial regression coefficient=0.714; multiple regression analysis , p<0.05). Masseter muscle stiffness was positively correlated with CPI (p< 0.05) and negatively correlated with maximum assisted mouth opening (p<0.05) and painless mouth opening (p<0.05). CONCLUSION: Shear wave elastography is useful to quantify masticatory muscle stiffness. Masseter muscle stiffness of females measured using shear wave elastography was about two-fold greater in group Ia and Ib than in the healthy control group.