Comparison of heat transfer through various fixed prosthetic materials during grinding.

PURPOSE: To measure and compare the mean temperature values due to heat generated during the grinding of different prosthetic materials with diamond burs using a high-speed instrument with and without water cooling. MATERIALS AND METHODS: In total, 120 disk-shaped specimens (10 × 2 mm), each with a smaller disk in the center (3 × 2 mm), were fabricated from yttrium-stabilized zirconia, monolithic zirconia, glass-ceramic, indirect composite, polyetheretherketone (PEEK), and cast metal (Ni-Cr alloy). The specimens were divided into six groups (n = 20) according to material type. The specimens in each group were ground continuously with a high-speed handpiece and diamond burs with (n = 10) and without (n = 10) water cooling until the smaller disks were removed. Two different methods (thermocouple and thermal camera) were used to measure the temperature during the grinding process. Results were analyzed using two-way ANOVA and paired samples t test (P < .05). RESULTS: PEEK had the lowest mean temperature values and metal had the highest values, both with and without water cooling, according to data measured with a thermocouple. Zirconia and monolithic zirconia samples without water cooling had the highest mean temperature values when measured with a thermal camera. Both with and without water cooling, composite samples had the lowest mean temperature value for thermal camera measurements. CONCLUSION: Water cooling is strongly recommended when grinding all prosthetic materials. The heat transferred to the supporting teeth may depend on the thermal conductivity of the material used.

The effect of different denture cleansing solutions on the retention of polyetheretherketone locator attachments.

PURPOSE: Prosthetic cleansing solutions have been reported to cause retention loss in implant locator attachments due to the chemical alterations of these attachments. This study aimed to investigate the effects of different denture cleansing solutions on attachments with different retention values. MATERIALS AND METHODS: In this study, 160 polyetheretherketone locator attachments were divided into 4 groups according to their attachment retention values (yellow, pink, clear, and violet). Forty attachments from each group were soaked in four different cleansing solutions (n = 10). The attachments from the four groups were immersed in water, sodium hypochlorite, Corega, and Protefix solutions for a period equivalent to 6 months, according to the manufacturer's recommendations. The locator attachments were then subjected to testing using a universal testing machine. Maximum load to dislodgement according to different solutions was evaluated by one-way ANOVA test. Statistical significance was set at p < 0.05. RESULTS: The effect of denture cleansing solutions on the retentive values of attachments was statistically significant (p < 0.001). Among all cleansing solutions, the highest retention value was found in the violet attachments, and the lowest retention value was found in the yellow attachments. The lowest retention value (0.72 ± 0.05 MPa) was observed when the yellow attachments were immersed in Protefix solution, and the highest retention value (1.96 ± 0.15 MPa) was observed when the violet attachments were immersed in the Corega solution. CONCLUSION: For different colored attachments, different cleansing solutions can be suggested to patients.

Oral health-related quality of life and psychological states of dental students with temporomandibular disorders.

PURPOSE/OBJECTIVES: This study investigates the frequency of temporomandibular disorders (TMD) in dental students, and evaluates the association between TMDs, psychological states, and oral health-related quality of life (OHRQoL). The presence of bruxism was also determined. METHODS: Two hundred ninety-three dental students completed the Symptom Checklist 90-Revised (SCL-90-R) and Oral Health Impact Profile 14 (OHIP-14) questionnaires and underwent a clinical examination according to Diagnostic Criteria for TMDs. RESULTS: TMDs were detected in 46.4% of the dental students. OHIP-14 scores of students with TMDs were significantly higher than scores for students without TMDs (p < 0.05). Significant differences were observed in all SCL-90-R scores among students with and without TMDs, except for phobic anxiety and additional SCL-90-R subscale scores (p < 0.05). The prevalence of myalgia was significantly higher in clinical students (26.6%) than in preclinical students (15.6%). OHIP-14 scores of clinical students were significantly higher than preclinical students (p < 0.05). CONCLUSIONS: In dental students, there was a high frequency of TMDs and bruxism. OHRQoL was poorer in clinical students. Levels of anxiety, depression, and somatization were not different in clinical and preclinical students. SCL-90-R scores are higher in students with TMDs except for phobic anxiety and additional SCL-90-R subscale scores.

Comparative Study of Chemical and Mechanical Surface Treatment Effects on The Shear Bond Strength of Polyether-Ether-Ketone to Veneering Resin.

PURPOSE: To assess the shear bond strength of composite resin to polyether ether ketone (PEEK) after mechanical and chemical surface treatments. MATERIALS AND METHODS: A total of 48 PEEK discs were fabricated and divided equally into four surface treatment groups (n = 12 each): (1) airborne particle abrasion with 50-µm alumina particles at 2 MPa pressure for 10 seconds; (2) 98% sulfuric acid etching for 1 minute; (3) airborne particle abrasion and sulfuric acid etching; and (4) no surface treatment. Specimens were conditioned, then Gradia composite veneer (GC) was applied to the PEEK surfaces and polymerized. Bond strength was measured with shear bond test using a universal testing machine. One-way analysis of variance and Tukey post hoc tests were applied for statistical analysis. RESULTS: The mean shear bond strength values of the sulfuric acid-etched group were higher than that of the airborne particle abrasion + acid etching, airborne particle abrasion, and control groups (P < .05). Mean shear bond strength values for the airborne particle abrasion + acid etching samples were higher than for the control and airborne particle abrasion groups (P < .05). CONCLUSION: There was no significant difference between the samples treated with airborne particle abrasion and the control group.

Polysomnographic characteristics of sleep-related bruxism: What are the determinant factors for temporomandibular disorders?

OBJECTIVE: This study aimed to evaluate the clinical and polysomnographic characteristics of sleep bruxism (SB) and delineate the determinant factors for temporomandibular disorders (TMD). METHODS: Forty-six patients were allocated into the SB group (n = 26) and control group (n = 20). The signs and symptoms of TMD were recorded using the Research Diagnostic Criteria for TMD. Patients underwent a full-night polysomnographic recording and masseter and temporal muscle electromyographic recordings. Clinical and polysomnographic data in patients with SB were analyzed in relation to TMD. RESULTS: The presence of TMJ sounds was significantly correlated with the number of bruxism bursts. Intra-articular pain in the TMJ was neither correlated with clinical nor polysomnographic parameters in patients with SB. CONCLUSION: Lower sleep efficiency in patients with SB was caused by a higher number of bruxism episodes. Morning headaches were associated with the severity of SB during rapid eye movement sleep.

Retrospective analysis of trauma incidence in patients with temporomandibular disorders.

BACKGROUND/AIM: The relationships between direct trauma, whiplash injuries, and temporomandibular disorders (TMD) have not been well established. The aim of this study was to evaluate the percentage of direct and/or whiplash trauma in patients with TMDs. MATERIAL AND METHODS: The clinical records of 237 patients with temporomandibular disorders who had sought treatment at the Orofacial Pain Clinic were reviewed. Clinical data for age and gender of the patients, history of trauma, temporomandibular joint (TMJ) sounds, and TMD diagnosis were extracted from the medical records of all included patients. The presence of TMJ sounds and TMD diagnosis had been determined based on the Research Diagnostic Criteria for TMDs. RESULTS: The mean age of patients with osteoarthritis was significantly higher than that of patients with disk displacement with reduction (P = .001, P Ë‚ .05). There was no statistically significant gender-based difference in diagnosis, clicking, crepitus, and trauma frequency (P > .05). A history of direct and whiplash trauma was observed in 18.6% and 14.8% of patients, respectively. Statistical analysis for the relationship between clicking and crepitus, and trauma showed no significant correlation (P > .05). CONCLUSION: Direct and/or whiplash trauma in patients with temporomandibular disorders were not associated with the diagnostic records and temporomandibular joint sounds.

Multilevel botulinum toxin type a as a treatment for spasticity in children with cerebral palsy: a retrospective study.

INTRODUCTION: Cerebral palsy is the most common cause of physical disability in children. Spasticity is a disabling clinical symptom that is prevalent among patients suffering from cerebral palsy. The treatment of spasticity with botulinum toxin type A (BTX-A) is a well-established option in the interdisciplinary management of spasticity, providing focal reductions in muscle tone in cerebral palsy patients. OBJECTIVE: The aim of this retrospective study was to describe the effect of multilevel BTX-A injections in the lower extremities, focusing mainly on gross motor function and functional status in cerebral palsy patients. METHODS: Data from 71 cerebral palsy patients (64% male, 36% female, mean age 6.7 +/-3.2 years) were analyzed retrospectively. We used the Ashworth and Tardieu scales to evaluate the degree of spasticity. Motor function was measured by the Gross Motor Function Measure (GMFM-88), and functional status was classified by the Gross Motor Function Classification System (GMFCS I-V). Multilevel BTX-A injections were applied after sedation and with electrostimulation guidance. The evaluations were repeated every three months, and the patients were followed for six months. RESULTS: We found that the Ashworth and Tardieu scores decreased significantly at the three-month evaluation (p<0.05) but not at the six-month evaluation (p>0.05). Although the improvement in spasticity was not maintained at the six-month evaluation, GMFM-88 scores increased significantly at the three- and six-month assessments. GMFSC levels showed no change in the three- and six-month assessments. CONCLUSION: We believe that a single multilevel BTX-A injection reduces spasticity and improves motor function in children with cerebral palsy.

Botulinum toxin injection of the subscapularis muscle.

Patients with hemiplegia frequently suffer from pain and have a limited range of motion (ROM) of the shoulder. The common pattern of shoulder movement in a patient with spastic hemiplegia is primarily adduction and internal rotation. Spasticity of the subscapularis muscle limits the abduction, external rotation and flexion of the shoulder. Injection of botulinum toxin or application of phenol can reduce the spasticity of the subscapularis muscle and various techniques to inject this muscle have been reported. We injected five patients with hemiplegia with botulinum toxin using our previously reported inferior approach, which is easy, safe and effective. We observed a reduction in pain and spasticity and improvement in the ROM of the shoulder for all patients.

Multilevel botulinum toxin type a as a treatment for spasticity in children with cerebral palsy: a retrospective study

INTRODUCTION: Cerebral palsy is the most common cause of physical disability in children. Spasticity is a disabling clinical symptom that is prevalent among patients suffering from cerebral palsy. The treatment of spasticity with botulinum toxin type A (BTX-A) is a well-established option in the interdisciplinary management of spasticity, providing focal reductions in muscle tone in cerebral palsy patients. OBJECTIVE: The aim of this retrospective study was to describe the effect of multilevel BTX-A injections in the lower extremities, focusing mainly on gross motor function and functional status in cerebral palsy patients. METHODS: Data from 71 cerebral palsy patients (64 percent male, 36 percent female, mean age 6.7 ±3.2 years) were analyzed retrospectively. We used the Ashworth and Tardieu scales to evaluate the degree of spasticity. Motor function was measured by the Gross Motor Function Measure (GMFM-88), and functional status was classified by the Gross Motor Function Classification System (GMFCS I-V). Multilevel BTX-A injections were applied after sedation and with electrostimulation guidance. The evaluations were repeated every three months, and the patients were followed for six months. RESULTS: We found that the Ashworth and Tardieu scores decreased significantly at the three-month evaluation (p<0.05) but not at the six-month evaluation (p>0.05). Although the improvement in spasticity was not maintained at the six-month evaluation, GMFM-88 scores increased significantly at the three- and six-month assessments. GMFSC levels showed no change in the three- and six-month assessments. CONCLUSION: We believe that a single multilevel BTX-A injection reduces spasticity and improves motor function in children with cerebral palsy.