Exploring botulinum toxin's impact on masseter hypertrophy: a randomized, triple-blinded clinical trial.

The present study aimed to assess the effectiveness and functional adverse effects of a single and multiple injections of botulinum toxin A (BoNT-A) for masseter hypertrophy (MH). Twenty-six women complaining about lower third facial enlargement due to MH, received 75 U of BoNT-A (abobotulinum toxin) in each masseter muscles. After 3 months, patients were randomly assigned to receive a second treatment session of Saline Solution: (G1; n = 11) or BoNT-A: (G2; n = 12). Muscle thickness (ultrasound), electrical activity (electromyography; EMG), masticatory performance, and subjective perception of MH were evaluated. Follow-up was performed at 1, 3 and 6 months. Muscle thickness, EMG activity, and masticatory performance were analyzed using ANOVA two-way and Sidak test as post-hoc. Masticatory performance was analyzed by the Friedman's test and Mann-Whitney test. Regarding inter-groups comparisons, there was a significant decrease in the left masseter muscle thickness in the G2 group at the 6 month follow-up (p < 0.02). For EMG, significant differences were evident at the 6 month assessment, with higher masseter activity for G1 (p < 0.05). For masticatory performance, no significant differences were observed throughout the study (p > 0.05) and a higher improvement in subjective perception of MH was observed in the 1 month follow-up for G2 (p < 0.05). In conclusion, BoNT-A is effective for MH, however multiple injections cause functional adverse effects in masseter muscle.

Trial data for precision analysis of a three-dimensional mandibular mechanical advantage.

The data presented in this manuscript describe craniofacial landmark coordinate values, muscle and load moment arm lengths, and mechanical advantage rates for constructing a three-dimensional model of masticatory muscles. Cone-beam computed tomography scans from 30 subjects (aged 12-19 years, 16 females) were used. Thirty-six craniofacial landmarks were identified. Subsequently, the moment arms for 7 muscles and their corresponding load moment arms at incisor and molar positions were determined. Then, the three-dimensional mechanical advantage for each muscle and tooth position was calculated as the ratio of muscle moment arm to load moment arm. This procedure was repeated three times by a main examiner and once by two other examiners. The Friedman test and the square root of the 'method of moments' variance estimator were used to compare data among examiners and calculate random errors, respectively. Although the values for the craniofacial landmark coordinates and biomechanical variables are very close, differences were found between measurements, especially in the interexaminer comparisons. Values served as the basis for reliability (intraclass correlation coefficient) and errors (average mean of absolute differences) analysis in the research paper titled "A three-dimensional method to calculate mechanical advantage in mandibular function: Intra- and interexaminer reliability study," published in the Journal of Orofacial Orthopedics.

Influence of the radius of Monson's sphere and excursive occlusal contacts on masticatory function of dentate subjects.

OBJECTIVE: To determine the influence of the radius of Monson's sphere, the number of posterior laterotrusive, mediotrusive, and protrusive contacts, and the chewing rate on food comminution. DESIGN: Sixty healthy dentate subjects, aged 21.22 ± 2.30 years, were selected. The three-dimensional coordinates of the cusp tips of the lower canine, premolar, and molar teeth were identified from the subjects' digital models. Monson's sphere was designed using the simplex method for function minimisation by adjusting the coordinates on its surface. The contacts were verified using 12 µm metal strips in jaw excursions at 0.5, 1.0, 2.0, and 3.0 mm. The masticatory performance and efficiency, swallowing threshold, and chewing rate were assessed through particle size fractionation. Data were analysed with multiple linear regression (α = 0.05). RESULTS: The sphere's radius, laterotrusive and protrusive contacts at 0.5 mm, and chewing rate were found to be negative predictor variables for masticatory performance until 20 chewing cycles (R2 = 0.429). For 40 cycles, the radius and total contacts (0.5 mm) were also explanatory factors (R2 = 0.223). Only the radius (R2 = 0.176) and the chewing rate (R2 = 0.082) were found to be significant for 60 cycles and swallowing threshold, respectively. Masticatory efficiency was influenced by masticatory performance until 40 and 60 cycles, as well as the radius and total contacts at 2.0 and 3.0 mm (R2 = 0.958). CONCLUSION: A larger radius of Monson's sphere and a greater number of posterior excursive contacts were found to be related to better masticatory function.

Effect of artificial eccentric occlusal interferences on masticatory performance: A randomised double-blind clinical trial.

BACKGROUND: Occlusal interferences lead to changes in mandibular kinematics to compensate and improve function. However, the effects of different types of eccentric disturbance on the comminution capacity are not known. OBJECTIVE: To determine the immediate effect of eccentric occlusal interferences on masticatory performance. METHODS: This crossover clinical trial included 12 healthy dentate subjects aged 25.2 ± 3.3 years who were randomly submitted to seven types of occlusal interference: unilateral and bilateral laterotrusive and mediotrusive, protrusive, dummy and control (no interference). The interference forms were planned in a semi-adjustable articulator, fabricated with composite resin and adhered to the mandibular first molars such that subjects' maximum intercuspation was maintained. Masticatory performance and the chewing rate during 20 cycles were evaluated during subjects' comminution of silicone test food under one interference condition per test day; the multiple sieve method was applied to the comminuted particles. The interference was removed upon test completion, and a 1-week washout period was applied between tests. RESULTS: Comminuted median particle sizes were larger under unilateral (4.94 ± 0.41 mm) and bilateral (4.81 ± 0.49 mm) laterotrusive, bilateral mediotrusive (4.65 ± 0.50 mm) and protrusive (4.83 ± 0.54 mm) interferences (p < .05) than under the control (4.01 ± 0.52 mm) and dummy (4.18 ± 0.58 mm) conditions (p < .05). Only unilateral and bilateral laterotrusive interferences narrowed the comminuted particle size dispersion (p < .05). The chewing rate did not differ among conditions (p = .1944). CONCLUSION: Artificial eccentric interferences had an immediate adverse effect on masticatory performance by resulting in larger comminuted particles. CLINICAL TRIAL REGISTRATION: Brazilian Registry of Clinical Trials (RBR-8g5zfg8).

Self-perceived oral health: a study with patients wearing removable dentures

Aim: This study aimed to investigate the relationship between self-perceived oral health and the prosthetic status of individuals who seek care in prosthodontics clinics. Methods: Self-perceived oral health was analyzed through the Geriatric Oral Health Assessment Index (GOHAI). Abutment tooth mobility was assessed, and denture status was determined by clinical assessment of stability, retention, occlusal balance, vertical dimension, and integrity of dentures. The frequency of individuals in each variable was determined for the low and very low GOHAI conditions. Chi-square, Pearson, and stepwise logistic regression tests were used for the statistical analyses (α = 0.05). Results: Ninety wearers of removable dentures with a mean age of 55.1±9.1 years were evaluated. None of the variables was related to GOHAI values (p > 0.05). The regression analysis showed that age predicts (p = 0.006) the variation of GOHAI conditions (OR = 0.924, CI = 0.873- 0.978), showing only 7.6% protective effect against very low GOHAI. Unsatisfactory stability showed the opposite effect (p = 0.034) and the individuals with this characteristic are more likely (OR = 3.055) to have very low GOHAI scores (CI = 1.085- 8.602). Conclusions: The self-perceived oral health of wearers of removable dentures worsens with age and unsatisfactory stability of dentures

A three-dimensional method to calculate mechanical advantage in mandibular function : Intra- and interexaminer reliability study.

PURPOSE: Masticatory muscles are physically affected by several skeletal features. The muscle performance depends on muscle size, intrinsic strength, fiber direction, moment arm, and neuromuscular control. To date, for the masticatory apparatus, only a two-dimensional cephalometric method for assessing the mechanical advantage, which is a measure for the ratio of the output force to the input force in a system, is available. This study determined the reliability and errors of a three-dimensional (3D) mechanical advantage calculation for the masticatory system. METHODS: Using cone-beam computed tomography images from teenage patients undergoing orthodontic treatments, 36 craniofacial landmarks were identified, and the moment arms for seven muscles and their load moment arms (biomechanical variables) were determined. The 3D mechanical advantage for each muscle was calculated. This procedure was repeated by three examiners. Reliability was verified using the intraclass correlation coefficient (ICC) and the errors by calculating the absolute differences, variance estimator and coefficient of variation (CV). RESULTS: Landmark coordinates demonstrated excellent intra- and interexaminer reliability (ICC 0.998-1.000; p < 0.0001). Intraexaminer data showed errors < 1.5 mm. Unsatisfactory interexaminer errors ranged from 1.51-5.83 mm. All biomechanical variables presented excellent intraexaminer reliability (ICC 0.919-1.000, p < 0.0001; CV < 7%). Interexaminer results were almost excellent, but with lower values (ICC 0.750-1.000, p < 0.0001; CV < 10%). However, the muscle moment arm and 3D mechanical advantage of the lateral pterygoid muscles had ICCs < 0.500 (p < 0.05) and CV < 30%. Intra- and interexaminer errors were ≤ 0.01 and ≤ 0.05, respectively. CONCLUSIONS: Both landmarks and biomechanical variables showed high reliability and acceptable errors. The proposed method is viable for the 3D mechanical advantage measure.

Effect of frozen storage on preservation of a silicone-based test food material

Aim: This study aimed to evaluate the effect of frozen storage on the physical properties of a silicone-based test food material, highly used to evaluate the masticatory performance in research settings. Methods: A total of 1,666 silicone cubes of Optosil Comfort® with 5.6-mm edges were shaped and stored at -18°C. The cubes were subsequently tested for flexural strength (maximum force, displacement, stress, and strain) before breaking (n = 136), changes in weight and size (n = 170), and masticatory performance (n = 1360) at eight timepoints: immediately after cube preparation (baseline, no freezing), and 1, 2, 3 and 4 weeks, and 2, 4 and 6 months after frozen storage. The cubes were thawed 8 h before each assessment. Results: The maximum force, stress, maximum displacement, and deformation values for the cubes were not affected by freezing (P > 0.05). At all of the time points, the cubes exhibited similar weight (P = 0.366) and size (identical values). The masticatory performance for the cubes also showed no differences from baseline through 6 months (P = 0.061). Conclusion: Freezing Optosil Comfort® silicone cubes did not alter the physical and mechanical properties of the material, being suitable to optimize the assessment of masticatory parameters for research purposes

Reliability and validity of a new colour-changing test food with an acid-base reaction for the clinical assessment of masticatory performance.

The aim of this study was to determine the reliability and validity of a new test food for the clinical assessment of masticatory performance. The test food had two overlapping acidic/basic halves. Ten dentate subjects chewed one unit for 10-100 cycles. One subject chewed ten units for the same number of cycles. Differences in the L*, a* and b* colour axes were determined before and after chewing by ANOVA. Colour guides were created based on the values of these axes and matched with the number of cycles. The reliability of the guides was evaluated using 30 images, where three examiners indicated the number of cycles in which the colour closest to that of a chewed material was found. The data were contrasted with the real values of the guides to determine the validity (Kappa coefficients). The equivalence of the guides with the median particle size (X50) was determined using equidimensional curves. The test food progressively changed from green to pink during chewing. As the number of cycles increased, the a* values increased and the b* values decreased (p < 0.05). Overall, the guides showed a Kappa value >0.8 for the intra-examiner and inter-examiner reliability and the validity comparisons. The a* and X50 values were inversely proportional to each other, and the b* values showed a direct relationship with the X50 values. The L* values did not show correspondence. The new test food showed high reliability and validity for the assessment of masticatory performance through clinical colour guides matched with the number of cycles and X50.

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.

The effect of stainable drinks followed by simulated brushing on the roughness and stainability of acrylic resins polymerized with different cycles.

STATEMENT OF PROBLEM: No information is available on roughness and stainability of acrylic resins polymerized by experimental microwave cycles after immersion in stainable liquids and simulated brushing. PURPOSE: The purpose of this in vitro study was to evaluate the effect of stainable drinks and brushing on roughness and stainability of acrylic resins (Vipi Cril [CA] and Vipi Wave [MA]) polymerized with different cycles. MATERIAL AND METHODS: CA and MA specimens (n=5; diameter, 20 mm; thickness, 3 mm) were made using 4 methods recommended by the manufacturer (water bath polymerization and microwave polymerization cycles) and experimental at 550 W or 650 W for 3 or 5 minutes (M550/3 and M650/5), respectively. After storage in distilled water at 37°C for 48 hours (T0), the specimens were stored in water, coffee, or red wine (37°C) for 36 days with simulated brushing (54 000 cycles, T1). Roughness (Ra) and stainability (ΔE/National Bureau of Standards) were measured at T0 and T1. Roughness and stainability data were analyzed by 3-way repeated measures and 2-way ANOVA, respectively, followed by the Bonferroni test (α=.05). RESULTS: After storing in coffee and brushing, CA showed the highest (M550/3=2.33 ±0.72 µm) and the lowest roughness (water bath polymerization=1.22 ±0.58 µm), whereas roughness of MA specimens processed by M650/5 increased (1.57 ±0.59 µm). Storing in wine and brushing increased roughness (1.75 ±0.32 µm) in the M550/3 group. No staining was observed on MA after brushing regardless of the polymerization cycle. All values were acceptable (ΔE≤3.3), except for MA (microwave polymerization), which showed National Bureau of Standards=4.49 (appreciable change) after storing in wine and brushing. CONCLUSIONS: A slight increase in material roughness was observed after staining and brushing. Only MA polymerized following manufacturer cycles showed relevant stainability after immersion in wine and brushing.

Patients' perception about the outcomes of prosthetic treatment in Southern Brazil - a cross sectional study

Aim: this study assessed the patients' perception of the outcomes of prosthetic treatment in a University of Southern Brazil. Methods: patients seeking for prosthetic treatment were invited to answer a questionnaire with 41 items about the potential risks, benefits, and consequences of no treatment. Answers were obtained according to a five-item Likert-scale varying from 1 (completely disagree) to 5 (completely agree). Sociodemographic data was included in the comparison. Mann-Whitney or Kruskal-Wallis (95%) compared data depending on the variable. Results: two-hundred twenty-five patients answered the questionnaire. Median age of participants was 45-54 years. The potential benefits were similar among participants irrespective of the variable adopted. The perception of risks was significant influenced by variables gender, age, education level, type of edentulous space, prior treatment with prosthodontics, type of prosthodontics, and prosthodontics usage in years. Consequences of no treatment were affected by age, prior treatment with prosthodontics, and prosthodontics usage in years. Conclusions: the study showed the fundamental importance of correct elucidation about the potential risks (negative perception) in the initial appointment for the studied population. Elucidation about the consequences of no treatment are relevant because some differences were seen into the variables. Prosthodontics patients from the city of Passo Fundo seem well informed about the benefits of the prosthetic treatment, besides the significant influence of some sociodemographic and prosthetic conditions

Reproducibility, Reliability, and Validity of Fuchsin-Based Beads for the Evaluation of Masticatory Performance.

PURPOSE: Rehabilitation of masticatory function is inherent to prosthodontics; however, despite the various techniques for evaluating oral comminution, the methodological suitability of these has not been completely studied. The aim of this study was to determine the reproducibility, reliability, and validity of a test food based on fuchsin beads for masticatory function assessment. MATERIALS AND METHODS: Masticatory performance was evaluated in 20 dentate subjects (mean age, 23.3 years) using two kinds of test foods and methods: fuchsin beads and ultraviolet-visible spectrophotometry, and silicone cubes and multiple sieving as gold standard. Three examiners conducted five masticatory performance trials with each test food. Reproducibility of the results from both test foods was separately assessed using the intraclass correlation coefficient (ICC). Reliability and validity of fuchsin bead data were measured by comparing the average mean of absolute differences and the measurement means, respectively, regarding silicone cube data using the paired Student's t-test (α = 0.05). RESULTS: Intraexaminer and interexaminer ICC for the fuchsin bead values were 0.65 and 0.76 (p < 0.001), respectively; those for the silicone cubes values were 0.93 and 0.91 (p < 0.001), respectively. Reliability revealed intraexaminer (p < 0.001) and interexaminer (p < 0.05) differences between the average means of absolute differences of each test foods. Validity also showed differences between the measurement means of each test food (p < 0.001). CONCLUSIONS: Intra- and interexaminer reproducibility of the test food based on fuchsin beads for evaluation of masticatory performance were good and excellent, respectively; however, the reliability and validity were low, because fuchsin beads do not measure the grinding capacity of masticatory function as silicone cubes do; instead, this test food describes the crushing potential of teeth. Thus, the two kinds of test foods evaluate different properties of masticatory capacity, confirming fushsin beads as a useful tool for this purpose.

A Survey of the Management of Patients with Temporomandibular Disorders by General Dental Practitioners in Southern Brazil.

PURPOSE: Temporomandibular disorders (TMD) are recognized as one of the most controversial topics in dentistry, despite the fact that both basic science and clinical researchers have currently reached some degree of consensus. This study aimed to conduct a questionnaire-based survey about the management of TMD patients by general dental practitioners (GDPs). MATERIALS AND METHODS: One hundred fifty-one GDPs with a private practice in a city of southern Brazil were included, independent of school of origin, gender, graduation year, and curriculum content. All participants were administered a questionnaire about the management of patients with TMD, and the responses were analyzed by binomial and chi-square tests (α = 0.05). RESULTS: Of the GDPs, 88.7% received TMD patients, who were primarily diagnosed on the basis of medical history (36.6%) or physical examination (30.4%). Of these, 65.4% referred the patients elsewhere, primarily to specialists in occlusion (36.1%) or orthodontics (29.7%). Occlusal splinting was the most commonly used management modality (20.8%), followed by occlusal adjustment (18.1%) and pharmacotherapy (16.6%). Splints were fabricated in maximum habitual intercuspation or centric relation depending on individual patient (54.8%). The hard stabilization form was the most common type of appliance used (35.0%). Moreover, 73.8% of the GDPs did not employ semi-adjustable articulators, and 69.5% adjusted the appliances at the time of fixing. The duration of splint use and the frequency of follow-up were considered patient dependent by 62.1% and 72.8%, respectively. GDPs considered the two major TMD etiologic categories as multifactorial (20.8%) and occlusion (19.9%). Multidisciplinary medical and dental treatment was considered necessary by 97.9%. CONCLUSIONS: The evaluated general dental practitioners manage TMD patients according to international guidelines.

Esthetic Rehabilitation of the Smile with No-Prep Porcelain Laminates and Partial Veneers.

Rehabilitation of patients with anterior conoid teeth may present a challenge for the clinician, especially when trying to mimic the nature with composite resins. This clinical report exemplifies how a patient with conoid upper lateral incisors was rehabilitated with minimally invasive adhesive restorations. Following diagnostic wax-up and cosmetic mock-up, no-prep veneers and ceramic fragments (partial veneers) were constructed with feldspathic porcelain. This restorative material presents excellent reproduction of the optical properties of the dental structure, especially at minimal thicknesses. In this paper, the details about the treatment are described. A very pleasing outcome was achieved, confirming that minimally invasive adhesive restorations are an excellent option for situations in which the dental elements are healthy, and can be modified exclusively by adding material and the patient does not want to suffer any wear on the teeth.

Conventional Complete Denture in Patients with Ectodermal Dysplasia.

Ectodermal dysplasia is described as heritable conditions that involve anomalies of structures derived from the ectoderm, including hypodontia. In the cases of edentulous young patients, who did not finish their craniofacial growth, treatment with conventional complete denture is a suitable alternative. The aim of this study was to report a case of mandibular edentulism treated with conventional complete denture in a thirteen-year-old patient diagnosed with hidrotic ectodermal dysplasia. Typical features, such as frontal bossing, depressed nasal bridge, protuberant lips, scarce hair, and brittle nails, were visualized during the extraoral examination. The intraoral inspection and radiographic analysis revealed oligodontia, dental malformation, and prolonged retention of deciduous teeth at maxilla and total edentulism at mandible. A conventional complete denture was planned and constructed following the same steps of technique as recommended in adults. Although this option is not a definitive treatment, the patient and his parents were satisfied with his improvement in chewing and speech, as well as with the aesthetic benefits.

The relationship between occlusal support and maxillary development: An animal study.

OBJECTIVE: To test the hypothesis that maxillary development may be affected by occlusal support. MATERIALS AND METHODS: The sample was composed by Wistar rats (5 weeks old) divided into three groups: Control (n = 10), extraction of mandibular molar teeth - left side (n = 10), extraction mandibular molar teeth - left and right sides (n = 10). The rats were sacrificed 8 weeks postextraction. Cone beam computed tomography scan images were taken for posterior measurement of maxillary length and width. Data were analyzed by one-way analysis of variance (Tukey test as post-hoc test). RESULTS: Maxillary length was significantly shorter (P < 0.005) in both groups after tooth extraction. No difference was observed regarding maxillary width and body weight. CONCLUSION: Reduced occlusal support may impair the development of the maxilla in rats.

Apexification of an Immature Permanent Incisor with the Use of Calcium Hydroxide: 16-Year Follow-Up of a Case.

Apexification is a process of forming a mineralized apical barrier and had been performed by using calcium hydroxide paste, due to its biological and healing performances in cases of existent trauma. This clinical report aims to report the results of a 16-year follow-up study of an apexification treatment applied to nonvital tooth 22 of a healthy 8-year-old male after a trauma. Clinical inspection of the tooth showed fractures of the incisal edge and mesial angle, absence of coronal mobility, and negative pulp vitality under cold testing. Radiographic analysis of the root revealed incomplete apex formation. The possibility of fracture into the root or luxation injury was rejected, and the diagnosis of pulp necrosis was verified. Apexification by calcium hydroxide and subsequent endodontic treatment were planned. Initial formation of the mineralized apical barrier was observed after 3 months, and the barrier was considered to be completed after 8 months. Clinical, radiographic, and CBCT examinations after 16 years verified the success of the treatment, although the choice of calcium hydroxide for apexification treatment is discussed.

O emprego do mock-up na Odontologia: trabalhando com previsibilidade / The use of mock-up in Dentistry: working with predictability

A Odontologia baseada em evidência engloba a necessidade de resultados previsíveis nos diversos tratamentos odontológicos, o que, consequentemente, deve conduzir a uma relação de confiança entre o paciente e o cirurgião dentista. O objetivo do presente trabalho é descrever, através de três casos clínicos, a técnica do mock-up e discutir no decorrer do manuscrito sua importância como ferramenta de diagnóstico e planejamento do tratamento reabilitador estético. Através domock-up, assegura-se o atendimento às expectativas estéticas do paciente em relação ao futuro tratamento, bem como resguarda o profissional de possíveis intercorrências. Esta técnica é bastante simples e eficiente, permitindo a visualização tridimensional do tratamento definitivo. Assim, o mock-up determina a previsibilidade dos resultados ao atuar como guia das decisões terapêuticas...

The evidence-based Dentistry encompasses the need for predictable results in the various dental treatments, which should therefore lead to a relationship of trust between patient and dentist. The objective of the present work was to describe through three clinical cases, the technique of mock-up and discuss throughout the manuscript its importance as a diagnostic and planning tool for aesthetic rehabilitation treatment. Through the mock-up, it can to ensure compliance the aesthetic expectations of the patient regarding the future treatment and protect the professional of possible complications. This technique is very simple and efficient, allowing three-dimensional visualization of definitive treatment. Thus, mock-up determines the predictability of results by guiding the therapeutic decisions...

Reproducibility of a silicone-based test food to masticatory performance evaluation by different sieve methods.

The aim of this study was to evaluate the reproducibility of the condensation silicone Optosil Comfort® as an artificial test food for masticatory performance evaluation. Twenty dentate subjects with mean age of 23.3±0.7 years were selected. Masticatory performance was evaluated using the simple (MPI), the double (IME) and the multiple sieve methods. Trials were carried out five times by three examiners: three times by the first, and once by the second and third examiners. Friedman's test was used to find the differences among time trials. Reproducibility was determined by the intra-class correlation (ICC) test (α=0.05). No differences among time trials were found, except for MPI-4 mm (p=0.022) from the first examiner results. The intra-examiner reproducibility (ICC) of almost all data was high (ICC≥0.92, p<0.001), being moderate only for MPI-0.50 mm (ICC=0.89, p<0.001). The inter-examiner reproducibility was high (ICC>0.93, p<0.001) for all results. For the multiple sieve method, the average mean of absolute difference from repeated measurements were lower than 1 mm. This trend was observed only from MPI-0.50 to MPI-1.4 for the single sieve method, and from IME-0.71/0.50 to IME-1.40/1.00 for the double sieve method. The results suggest that regardless of the method used, the reproducibility of Optosil Comfort® is high.

Histopathological changes by the use of soft reline materials: a rat model study.

AIM: To assess the histopathological changes of rat palatal mucosa exposed to soft reline materials. METHODS: Forty-five adult female Wistar rats with controlled living conditions and fed ad libitum were employed. Palatal appliances of heat-polymerized acrylic resin Lucitone 550 were manufactured and worn by forty animals during 14 days. Five animals did not use the appliances (G1) and were used to control the appliance influence. One experimental group (n = 10) used the appliances without any relining material (G2) to control the material effect. Three experimental groups (n = 10) received the following soft reline materials below appliances: Dentusoft (G3), Dentuflex (G4), and Trusoft (G5). Appliances from half of each experimental group(n = 5) was immersed in water bath at 55°C for 10 min before use. Animals were slaughtered and the palates were fixed in 10% buffered formalin. Hematoxylin and eosin stained sections of 5 µm were analyzed by computerized planimetry. Cellular compartment, keratin and total epithelial thickness, and basement membrane length were measured to histopathological description.Analysis of variance and Tukey post-hoc test were used to data examination(α = 0.05). RESULTS: For heat-treatment groups, G4 showed less elongated ridges at the basal layer interface (p = 0.037) than G2. When comparing the conditions with and without heat-treatment, only G2 showed a significant decrease in the cellular compartment, keratin layer and total epithelium thickness (p<0.05). CONCLUSION: The post-polymerization for Lucitone 550 was an effective method to reduce the changes in the rat palatal mucosa. The soft reline materials tested did not cause significant histopathological changes in the rat palatal mucosa.