Degenerate dentition of the dugong (Dugong dugon), or why a grazer does not need teeth: morphology, occlusion and wear of mouthparts

The morphology and functional occlusion of the cheekteeth of 57 dugongs Dugong dugon of both sexes were examined using reflected light and scanning electron microscopy, radiography, hardness testing and skull manipulation. The functional morphology of the horny oral pads was also described. Mouthparts and body size allometry was examined for ontogenetic and gender-related trends. We found that the worn erupted cheekteeth of the dugong are simple flat pegs composed of soft degenerative dentine. During occlusion, the mandible moves in a mainly antero-lingual direction, with the possibility of mandibular retraction in some individuals. Anterior parts of the cheektooth row may become non-functional as a dugong ages. As a function of body size, dugong cheekteeth are extremely small compared with those of other mammalian herbivores, and with other hindgut fermenters in particular. The morphology, small size and occlusal variability of the cheekteeth suggest that there has not been strong selective pressure acting to maintain an effective dentition. In contrast, great development of the horny pads and associated skull parameters and their lower size variability suggest that the horny pads may have assumed the major role in food comminution.

Complete denture occlusion: an evidence-based approach

Purpose: This study involved an extensive search for randomized controlled clinical trials comparing bilateral balanced and canine-guided dentures, and questioned whether a bilateral balanced occlusion is imperative for successful denture treatment. Materials and Methods: Studies were identified by searching electronic databases (PubMed/MEDLINE, ISI Web of Science, LILACS, and BBD). The keywords “denture” and “occlusion” were used. The minimum inclusion requirements were (1) randomized controlled trials with patients of any age wearing both maxillary and mandibular conventional complete dentures (CDs), (2) comparison between bilateral balanced and canine-guided dentures, and (3) assessment of masticatory function and/or patients’ satisfaction. Results: The search resulted in the identification of 5166 articles. Subsequently, 5156 articles were excluded on the basis of title and abstract. By the end of the search phase, seven randomized controlled trials were considered eligible. Conclusions: Current scientific evidence suggests that bilateral balanced occlusion is not imperative for successful treatment with conventional CDs in average patients. More studies are necessary to identify if specific clinical conditions may benefit from a balanced occlusion.

Mastigatory efficiency in denture wears with bilateral balanced occlusion and canine guidance

The maintenance of masticatory function is especially important for patients wearing complete dentures due to their limitations. Thus, the bilateral balanced occlusal concept is used to achieve greater masticatory efficiency. However, a critical review of the literature reveals that there is not sufficient scientific evidence to support bilateral balanced occlusion as the most appropriate occlusal concept in complete dentures. Therefore, the aim of this study was to evaluate the masticatory efficiency in complete dentures wearers with bilateral balanced occlusion and canine guidance. A double-blinded controlled crossover clinical trial was conducted. The sample was composed by 24 edentulous patients who wore sets of complete dentures with both occlusal concepts during equal periods of 3 months. Objective data were collected through the masticatory efficiency test performed by the colorimetric method with the beads, in which capsules of a synthetic material enclosing fuchsine-containing granules were used. Subjective data were recorded by patient's ratings of their chewing function. No significant statistical difference was found for masticatory efficiency (p=0.095) between the two occlusal concepts studied. The results suggest that bilateral balanced occlusion does not improve the masticatory efficiency in complete denture wearers.

Mastigatory efficiency in denture wears with bilateral balanced occlusion and canine guidance

The maintenance of masticatory function is especially important for patients wearing complete dentures due to their limitations. Thus, the bilateral balanced occlusal concept is used to achieve greater masticatory efficiency. However, a critical review of the literature reveals that there is not sufficient scientific evidence to support bilateral balanced occlusion as the most appropriate occlusal concept in complete dentures. Therefore, the aim of this study was to evaluate the masticatory efficiency in complete dentures wearers with bilateral balanced occlusion and canine guidance. A double-blinded controlled crossover clinical trial was conducted. The sample was composed by 24 edentulous patients who wore sets of complete dentures with both occlusal concepts during equal periods of 3 months. Objective data were collected through the masticatory efficiency test performed by the colorimetric method with the beads, in which capsules of a synthetic material enclosing fuchsine-containing granules were used. Subjective data were recorded by patient's ratings of their chewing function. No significant statistical difference was found for masticatory efficiency (p=0.095) between the two occlusal concepts studied. The results suggest that bilateral balanced occlusion does not improve the masticatory efficiency in complete denture wearers.

Plagiocéphalie unilatérale frontale non syndromique : association avec l'inclinaison du plan d'occlusion et de la déviation controlatérale de la mandibule

Mémoire numérisé par la Direction des bibliothèques de l'Université de Montréal.

A cardiovascular occlusion method based on the use of a smart hydrogel

Smart hydrogels for biomedical applications are highly researched materials. However, integrating them into a device for implantation is difficult. This paper investigates an integrated delivery device designed to deliver an electro-responsive hydrogel to a target location inside a blood vessel with the purpose of creating an occlusion. The paper describes the synthesis and characterization of a Pluronic/methacrylic acid sodium salt electro-responsive hydrogel. Application of an electrical bias decelerates the expansion of the hydrogel. An integrated delivery system was manufactured to deliver the hydrogel to the target location in the body. Ex vivo and in vivo experiments in the carotid artery of sheep were used to validate the concept. The hydrogel was able to completely occlude the blood vessel reducing the blood flow from 245 to 0 ml/min after implantation. Ex vivo experiments showed that the hydrogel was able to withstand physiological blood pressures of > 270 mm·Hg without dislodgement. The results showed that the electro-responsive hydrogel used in this paper can be used to create a long-term occlusion in a blood vessel without any apparent side effects. The delivery system developed is a promising device for the delivery of electro-responsive hydrogels.

Plagiocéphalie unilatérale frontale non syndromique : association avec l'inclinaison du plan d'occlusion et de la déviation controlatérale de la mandibule

Mémoire numérisé par la Direction des bibliothèques de l'Université de Montréal.

Small bowel occlusion due to giant perineal hernia: abdominal approach with plastic perineal reconstruction

A perineal hernia is defined as a protrusion of peritoneal or extraperitoneal content through a pelvic floor defect. A 64-year-old woman with a bowel occlusions due to a giant postoperative perineal hernia was admitted to our hospital. We describe abdominal approach with plastic perineal reconstruction.

Left atrial appendage: anatomy and imaging landmarks pertinent to percutaneous transcatheter occlusion

Percutaneous left atrial appendage (LAA) closure represents a complementary option and effective treatment for patients at risk of thromboembolism, especially in patients for whom it may be difficult to achieve satisfactory anticoagulation control or where anticoagulation treatment is not possible or desirable. Effective and safe transcatheter LAA occlusion requires a detailed knowledge of crucial anatomic landmarks and endocardial morphologic variants of the LAA and its neighbouring structures.1 ,2 w1–w3 Our aim in this article is to provide the basic anatomic information that is important for the interventional cardiologist to know when planning an LAA occlusion procedure.

Relationship Between Orofacial Function, Dentofacial Morphology, And Bite Force In Young Subjects.

The aim was to evaluate the relationship between orofacial function, dentofacial morphology, and bite force in young subjects. Three hundred and sixteen subjects were divided according to dentition stage (early, intermediate, and late mixed and permanent dentition). Orofacial function was screened using the Nordic Orofacial Test-Screening (NOT-S). Orthodontic treatment need, bite force, lateral and frontal craniofacial dimensions and presence of sleep bruxism were also assessed. The results were submitted to descriptive statistics, normality and correlation tests, analysis of variance, and multiple linear regression to test the relationship between NOT-S scores and the studied independent variables. The variance of NOT-S scores between groups was not significant. The evaluation of the variables that significantly contributed to NOT-S scores variation showed that age and presence of bruxism related to higher NOT-S total scores, while the increase in overbite measurement and presence of closed lip posture related to lower scores. Bite force did not show a significant relationship with scores of orofacial dysfunction. No significant correlations between craniofacial dimensions and NOT-S scores were observed. Age and sleep bruxism were related to higher NOT-S scores, while the increase in overbite measurement and closed lip posture contributed to lower scores of orofacial dysfunction.

Kinesiographic Study Of Masticatory Movements In Denture Wearers With Normal And Resorbed Denture-bearing Areas.

An unfavorable denture-bearing area could compromise denture retention and stability, limit mastication, and possibly alter masticatory motion. The purpose of this study was to evaluate the masticatory movements of denture wearers with normal and resorbed denture-bearing areas. Completely edentulous participants who received new complete dentures were selected and divided into 2 groups (n=15) according to the condition of their denture-bearing areas as classified by the Kapur method: a normal group (control) (mean age, 65.9 ± 7.8 years) and a resorbed group (mean age, 70.2 ± 7.6 years). Masticatory motion was recorded and analyzed with a kinesiographic device. The patients masticated peanuts and Optocal. The masticatory movements evaluated were the durations of opening, closing, and occlusion; duration of the masticatory cycle; maximum velocities and angles of opening and closing; total masticatory area; and amplitudes of the masticatory cycle. The data were analyzed by 2-way ANOVA and the Tukey honestly significant difference post hoc test (α=.05). The group with a resorbed denture-bearing area had a smaller total masticatory area in the frontal plane and shorter horizontal masticatory amplitude than the group with normal denture-bearing area (P<.05). Denture wearers with resorbed denture-bearing areas showed reduced jaw motion during mastication.

Prospects For Early Investigational Therapies For Sickle Cell Disease.

Sickle cell disease (SCD) is a genetic disorder characterized by the production of abnormal hemoglobin that polymerizes at low oxygen concentrations, causing the erythrocyte to adopt a sickle-shaped morphology. SCD pathophysiology is extremely complex and can lead to numerous clinical complications, including painful vaso-occlusive crises (VOC), end-organ damage, and a shortened lifespan. An impressive number of investigational drugs are currently in early stages of clinical development with prospects for use either as chronic therapies to reduce VOC frequency and end-organ damage in SCD or for use at the time of VOC onset. Many of these agents have been developed using a pathophysiological-based approach to SCD, targeting one or more of the mechanisms that contribute to the disease process. It is plausible that a multi-drug approach to treating the disease will evolve in the coming years, whereby hydroxyurea (HU) (the only drug currently FDA-approved for SCD) is used in combination with drugs that amplify nitric oxide signaling and/or counteract hemolytic effects, platelet activation and inflammation.

Assessment Of Sleep Bruxism, Orthodontic Treatment Need, Orofacial Dysfunctions And Salivary Biomarkers In Asthmatic Children.

To evaluate the sleep bruxism, malocclusions, orofacial dysfunctions and salivary levels of cortisol and alpha-amylase in asthmatic children. 108 7-9-yr-old children were selected from Policlinic Santa Teresinha Doutor Antonio Haddad Dib (asthmatics, n=53) and from public schools (controls, n=55), Piracicaba, SP, Brazil. Sleep bruxism diagnosis was confirmed by parental report of grinding sounds and the presence of shiny and polish facets on incisors and/or first permanent molars. The index of orthodontic treatment need was used for occlusion evaluation. Orofacial dysfunctions were evaluated using the nordic orofacial test-screening (NOT-S). Salivary cortisol and alpha-amylase were expressed as awakening response (AR), calculated as the difference between levels immediately after awakening and 30min after waking, and diurnal decline (DD), calculated as the difference between levels at 30min after waking and at bedtime. Data were analyzed using Shapiro-Wilk/Kolmogorov-Smirnov, Chi-square, unpaired t test/Mann-Whitney and paired t/Wilcoxon tests. Sleep bruxism was more prevalent in children with asthma than controls (47.2% vs. 27.3%, p<0.05). Asthmatics had higher scores of NOT-S total and interview (p<0.05). Dysfunctions on sensory function and chewing and swallowing were more frequent in asthmatics (p<0.05). Salivary cortisol AR on weekend was significantly higher for asthmatics (p<0.05). Salivary cortisol DD was significantly higher on weekday than weekend for controls (p<0.05). There were no significant differences in alpha-amylase values in and between groups. The presence of asthma in children was associated with sleep bruxism, negative perception of sensory, chewing and swallowing functions, and higher concentrations of salivary cortisol on weekend.