Periodontal health and esthetic results in impacted teeth exposed by apically positioned flap technique

Objectives: This study evaluates the periodontal health status and the esthetic results of teeth subjected to orthodontic traction, after their exposure by an apically positioned flap. Study design: Fifteen patients were included in the study, ages between 11 and 28 years old. The fenestrated teeth and their homologous contralateral normally erupted teeth, used as control, were evaluated. Results: Statistically significant differences were found in the position of the gingival margin (p = 0.005), with an average distance between cemento-enamel junction (CEJ) and gingival margin of 2.47 mm (SD 1.19) in control teeth and of 1 mm (SD 1.31) in the operated teeth, and in the depth of palatal probing (p = 0.031), with 2.1 mm (SD 0.9) for the experimental teeth and 1.7 mm (SD 0.8) for the control teeth. The gingival index, the bleeding during probing and the probing depth did not show statistically significant differences. The patient"s subjective esthetic evaluation was more favorable for the control teeth in most of the cases. Conclusions: The surgical approach for the impacted teeth by means of the apically positioned flap resulted to be a predictable technique allowing the maintenance of the periodontal health on a long-term basis.

Multiple supernumerary teeth not associated with complex syndromes: a retrospective study

Objectives: To determine the epidemiology and describe the clinical and radiographic characteristics, the type of treatment, and the possible delayed appearance of new supernumerary teeth in patients with non-syndromic multiple hyperdontia. Patients and Methods: We conducted a small retrospective observational study of 8 patients diagnosed with nonsyndromic multiple hyperdontia. Multiple hyperdontia not associated to complex syndromes was defined as apparently generally healthy patients with one or more supernumerary teeth in two or more areas. Results: The average patient age was 16.23 years; males predominated (3:1). Multiple hyperodontia with a minimum of 2 and a maximum of 9 supernumerary teeth was found (total: 34 mean: 4.25). The most frequent location was the upper jaw (76.47%). Eumorphic teeth were seen at lower premolar level, while the rest were all heteromorphic. There was altered eruption of the contiguous teeth of 4 of the impacted supernumerary teeth all the rest being asymptomatic. Extraction was the treatment in all patients, and in one of them the delayed appearance of 4 supernumerary teeth was detected. Conclusions: Multiple hyperodontia rarely occurs without being associated with complex syndromes. Prophylactic surgical removal of the supernumerary teeth is generally the treatment of choice.

Retrospective study of 145 supernumerary teeth

Objective: The goal of the present retrospective study is to describe the distribution of the supernumerary teeth in a population of patients that have been attended at the Public Clinic of the Department of Oral Surgery. Background: Supernumerary teeth and multiple hyperdontia are usually associated with different syndromes, such as Gardner syndrome, or with facial fissures; however, they can appear in patients without any pathology. Their prevalence oscillates to 0.5-3.8% in patients with permanent teeth and to 0.35-0.6% in patients with primary teeth. Patients and Methods: A total of 36,057 clinical histories of patients that were admitted at the clinic between September of 1991 and March of 2003 were revised. The following data were extrapolated: age, sex, number of extracted supernumerary teeth, localization, morphology and type of supernumerary teeth. Consequently, 102 patients were included into the present study. Results: Of the 147 supernumerary teeth identified in the oral cavities of patients 145 were extracted. The most frequent supernumerary teeth identified were mesiodens (46.9%), followed by premolars (24.1%) and fourth molars or distal molars (18%). As for location, 74.5% of the supernumerary teeth were found in the superior maxillary bone and 46.9% of the supernumerary teeth were present in the palatine/lingual area. Heteromorphology was found in two thirds of the supernumerary teeth, with conical shape being the most frequent. Finally, 29.7% of the supernumerary teeth had occlusion with permanent teeth, and mesiodens were the predominating type of supernumerary teeth that showed this feature. Conclusions: Mesiodens very frequently cause retention of permanent incisors, which erupt spontaneously after the extraction of supernumerary teeth, if there is sufficient space in the dental arch and if they conserve the eruptive force. Generally, supernumerary premolars are eumorphic and are casually discovered during radiological exam, if not producing any symptomology.

Tracking the ghost of coevolution in specific plant-insect interactions : the case of the pollination system between the globeflower Trollius europaeus and seven european Chiastocheta flies

This study aims at understanding the evolutionary processes at work in specialized species interactions. Prom the macroevolutionary perspective, coevolution among specialized taxa was proposed to be one of the major processes generating biodiversity. We challenge this idea from the theoretical and practical perspective and through a literature review and show that the major hypotheses linking coevolutionary process with macroevolutionary patterns do not necessarily predict lineage co diversification and parallel speciation, limit¬ing the utility of the comparative phylogenenetic approach for investigating coevolution¬ary processes. We also point to the rarity of observed long-term coevolutionary dynamics among lineages and propose that coevolution rather occurs in shorter timescales, followed by ecological fitting. Prom the empirical point, we focus on the nursery pollination interaction between the European globeflower Trollius europaeus (Ranunculaceae) and its associated Chiastocheta flies (Anthomyiidae; Diptera) as a model system of evolution and maintenance of special¬ized interactions. The flies are obligate parasites of the seeds, but also pollinate the plant - it was thus proposed that both species are mutually dependent. Contrasting with the paradigm used for two decades of research on this system, we show that the female fitness component of the plant is similar in the populations with and without Chiastocheta. The plant is thus not exclusively dependent on the flies for reproduction. We discuss this result in the context of the factors responsible for the evolution of mutualistic systems. Understanding the evolution of a biological system requires understanding of its phylo- genetic context. Previous studies showed large mismatch between mtDNA phylogeny and morphological taxonomy in Chiastocheta. By using a large set of RAD-sequencing loci, we delineate the species limits that are congruent with morphology, and show that the discordance is best explained by the scenario of mitochondrial capture among fly species. Finally, we examine this system from a phylogeographic perspective, and identify the lack of congruence in spatial genetic structures of the plant and associated insects across their whole geographic range. The flies show lower numbers of spatial genetic groups than the plant, indicating that not all of the plant réfugia were shared by all the fly species or that the migration dynamics homogenized some of the groups. The incongruence in spatial genetic patterns indicates that fly migrations were largely independent from the genetic background of the plant, following rather a scenario of resource tracking, without the signature of coevolutionary process at this scale. Indeed, while the flies require the plant to survive climatic oscillations, the opposite is not true. Eventually, we show that there is no phylogenetic signal of spatial genetic structures, meaning that neither histories nor life- history traits are shared among closely related species and that species are characterized by unique trajectories of their genes. -- Cette étude vise à comprendre les processus évolutifs à l'oeuvre au sein d'interactions en¬tre espèces spécialisées. Du point de vue macroévolutif, la coévolution entre les taxons spécialisée a été considérée comme l'un des principaux processus générateur de biodiversité. Nous contestons cette idée du point de vue théorique et pratique à travers une revue de la littérature. Nous montrons que les hypothèses majeures reliant les processus coévolutifs avec les patterns de diversité au niveau macroévolutif ne prédisent pas nécessairement la co- diversification des lignées et leur spéciation parallèle, ce qui limite l'utilité de l'approche de phylogénie comparative pour étudier les processus coévolutifs . Nous rappelons également le peu d'exemples de dynamique coévolutive à long terme et proposons que la coévolution se produit plutôt dans des intervalles courts, suivis d'ajustements écologiques. Du point empirique, nous nous concentrons sur l'interaction de pollinisation entre le Trolle d'Europe Trollius europaeus (Ranunculaceae) et ses pollinisateurs associés, du genre Chiastocheta (Anthomyiidae; Diptera) en tant que système-modèle pour étudier l'évolution et le maintien des interactions spécialisées. Les mouches sont des parasites obligatoires des semences, mais pollinisent également la plante. Il a donc été proposé que les deux espèces soient mutuellement dépendantes. Contrastant avec le paradigme utilisé pendant deux décennies de recherche sur ce système, nous montrons, que la composante de fitness femelle de la plante est similaire dans les populations avec et sans Chiastocheta. La plante ne dépend donc pas exclusivement de son interaction avec les mouches pour la reproduction. Nous discutons de ce résultat dans le contexte des facteurs responsables de l'évolution des systèmes mutualistes. Comprendre l'évolution d'un système biologique nécessite la compréhension de son con- texte phylogénétique. Des études antérieures ont montré, chez Chiastocheta, de grandes disparités entre les phylogénies obtenues à partir d'ADN mitochondrial et la taxonomie basée sur les critères morphologiques. En utilisant un grand nombre de loci obtenus par RAD-sequencing, nous traçons les limites des espèces, qui concordent avec les car¬actéristiques morphologies, et montrons que la discordance s'explique en fait par un scénario de capture mitochondriale entre espèces de mouches. Enfin, nous examinons le système d'un point de vue phylogéographique, et identi¬fions les incohérences entre structurations génétiques spatiales de la plante et des insectes associés dans toute leur aire de distribution géographique. Les mouches présentent un nombre de groupes génétiques inférieur à la plante, indiquant que tous les refuges de la plante n'étaient pas partagés par toutes les espèces de mouches ou que les dynamiques migratoires ont homogénéisés certains des groupes chez les mouches. Les différences ob¬servées dans les patrons de structuration génétique spatiale indique que les migrations et dispersions des mouches ont été indépendantes du contexte génétique de la plante, et ces dernières ont été uniquement tributaires de la disponibilité des ressources, sans qu'il n'y ait de signature du processus de coévolution à cette échelle. En effet, tandis que les mouches ont besoin de la plante pour survivre aux oscillations climatiques, le contraire n'est pas exact. Finalement, nous montrons qu'il n'y a pas de signal phylogénétique des structurations génétiques spatiales chez les mouches, ce qui signifie que ni l'histoire, ni les traits d'histoire de vie ne sont partagés entre les espèces phylogénétiquement proches et que les espèces sont caractérisées par des trajectoires uniques de leurs gènes.

Fatigue resistance of denture teeth

AIMS: There is no standard test to determine the fatigue resistance of denture teeth. With the increasing number of patients with implant-retained dentures the mechanical strength of the denture teeth requires more attention and valid laboratory test set-ups. The purpose of the present study was to determine the fatigue resistance of various denture teeth using a dynamic load testing machine. METHODS: Four denture teeth were used: Bonartic II (Candulor), Physiodens (Vita), SR Phonares II (Ivoclar Vivadent) and Trubyte (Dentsply). For dynamic load testing, first upper molars with a similar shape and cusp inclination were selected. The molar teeth were embedded in cylindrical steel molds with denture base material (ProBase, Ivoclar Vivadent). Dynamic fatigue loading was carried out on the mesio-buccal cusp at a 45° angle using dynamic testing machines and 2,000,000 cycles at 2Hz in water (37°C). Three specimens per group and load were submitted to decreasing load levels (at least 4) until all the three specimens no longer showed any failures. All the specimens were evaluated under a stereo microscope (20× magnification). The number of cycles reached before observing a failure, and its dependence on the load and on the material, has been modeled using a parametric survival regression model with a lognormal distribution. This allowed to estimate the fatigue resistance for a given material as the maximal load for which one would observe less than 1% failure after 2,000,000 cycles. RESULTS: The failure pattern was similar for all denture teeth, showing a large chipping of the loaded mesio-buccal cusp. In our regression model, there were statistically significant differences among the different materials, with SR Phonares II and Bonartic II showing a higher resistance than Physiodens and Trubyte, the fatigue resistance being estimated at around 110N for the former two, and at about 60N for the latter two materials. CONCLUSION: The fatigue resistance may be a useful parameter to assess and to compare the clinical risk of chipping and fracture of denture tooth materials.

Dental Health in Primary Teeth after Prevention of Mother-Child Transmission of Mutans Streptococci. A Historical Cohort Study on Restorative Visits and Maternal Prevention Costs

Mutansstreptokokkitartunnan ehkäisemisen pitkäaikaisvaikutukset maitohampaiden terveyteen. Kohorttitutkimus korjaavan hoidon määrästä ja kariesehkäisyn kustannuksista. Tutkimuksen tarkoituksena oli selvittää varhaisen mutansstreptokokki (MS)-kolonisaation ehkäisyn pitkäaikaisvaikutuksia korkean kariesriskin omaavien lasten maitohampaistossa sekä tarkastella MS-tartunnan estämisen kustannuksia. Tiedot lasten hampaiden terveydestä ja hammashoitotoimenpiteistä syntymästä 10-vuotiaaksi sekä äiteihin kohdistuneen kariesehkäisyn kustannuksista kerättiin Ylivieskan terveyskeskuksen asiakirjoista. Tutkimuksessa oli mukana yhteensä 507 lasta, heistä 148 oli osallistunut aikaisempaan Ylivieskan äiti-lapsitutkimukseen, jossa verrattiin äitien käyttämän ksylitolipurukumin ja äidille tehtyjen fluori- tai klooriheksidiinilakkausten vaikutusta pikkulasten hampaiden terveyteen. Maitohammaskariesta esiintyi 10-vuotiaaksi asti merkitsevästi vähemmän lapsilla, jotka eivät olleet saaneet MS-tartuntaa alle 2-vuotiaana, heidän maitohampaansa säilyivät 3,4 vuotta kauemmin täysin ehjinä (p<0.001) ja he tarvitsivat vähemmän maitohampaiden korjaavaa hoitoa (p=0.005) kuin lapset, joiden hampaisto oli kolonisoitunut MS-bakteerilla jo 2-vuotiaana. Koska ksylitoliryhmän lasten MS-kolonisaatio oli vähäisintä, heidän maitohampaissaan oli vähemmän kariesta ja korjaavan hoidon tarvetta kuin kahden muun korkeariskisen ryhmän lapsilla. Äitien käyttämän ksylitolipurukumin kustannukset olivat yhteensä 116 euroa ja lapsen maitohampaiden säilyminen täysin ehjinä vuoden pidempään maksoi 37 euroa. Kun MS-tartunta oli saatu estettyä, korkean kariesriskin omaavien lasten hampaiden terveys oli samalla tasolla kuin keskimäärin koko ikäkohortilla. Lapsen maitohampaat säilyvät terveinä pidempään ja korjaavan hoidon tarve vähenee, kun MS-kolonisaatio alle 2-vuotiaana saadaan estettyä. Lapsen MS-kolonisaatio vähenee merkitsevästi, kun äiti käyttää ksylitolipurukumia lapsen ollessa 0-2 vuoden ikäinen, siten pikkulapsen äidin säännöllinen ksylitolipurukumin käyttö saattaa olla julkisen tereydenhuollon kannalta tarkoituksenmukainenterveyttä edistävä menetelmä.

Histopathological and histomicrobiological study of root canal therapy medication, comparison of calcium hydroxide versus gutta-percha with zinc oxide/eugenol in the teeth of dogs

The presence of microorganisms in dental structures with experimentally induced necrosis was evaluated. The materials were tested to evaluate their antimicrobial activity and tissue repair efficacy. Four dogs were used in this experiment, with a total of 64 roots of premolar teeth, divided into three groups. The root canals of Group I were filled with gutta-percha and zinc oxide/eugenol cement; Group II were filled with calcium hydroxide, and Group III were not filled. All animals were clinically and radiographically examined 15 days after surgery andthen again every subsequent 15 days until 120 days, when the teeth were extracted en bloc.Histopathological analysis showed inflammatory infiltration, cement and bone resorption andnecrotic tissue in the apical delta in different proportions. Histomicrobiological analysis showedthe presence of microorganisms inside the teeth structures, with different concentrationsaccording to the treatment used. There was statistical significance between the groups(p>0.05). Gutta-percha with zinc oxide/eugenol demonstrated good antimicrobial activity;calcium hydroxide was not efficient. The conclusion of this study is that gutta-percha withzinc oxide/eugenol is the better protocol for filling root canals in dogs.

The effect of timing temporary cements to treat induced pulp necrosis in the teeth of dogs

During endodontic therapy (pulpectomy, root canal debridement and root canal filling) microbiological management is a major concern. Bacteria present in dentine tubules, apical foramina and apical delta are causally related to failure of the procedure. Studies have shown that during single session endodontic treatment bacteria remain within dental structures. The aim of the present study was to evaluate endodontic treatment performed as two sessions, using temporary endodontic dressing materials for different periods in four groups of experimental dogs. A total of 80 roots of second and third upper premolar teeth and second, third and fourth lower premolar teeth were divided into four groups. The pulp chamber was opened with burrs and the pulp exposed for 60 days to induce pulpal inflammation and necrosis. Groups II, III and IV were treated with calcium hydroxide plus camphorated paramono-chlorophenol (PMCC) for 7, 15 and 30 days, respectively. In all groups, the root canals were filled with zinc oxide-eugenol and gutta-percha cones. Clinical and radiographical measurements were performed every 2 weeks. After 60 days a small block section containing the teeth, surrounding periapical tissues and the periodontium was removed for histological and microbiological study. Histological analysis revealed intense inflammatory response in all groups. Microbiological analysis showed microbial reduction inversely proportional to the period of time that the intracanal temporary medicament was left in place.

Macroscopic description of teeth of Azara's agouti (Dasyprocta azarae)

The teeth of Azara's agouti (Dasyprocta azarae) were described macroscopically in order to provide biological data on one of the largest wild rodents of the Americas. Radiography was taken on six heads and the teeth were described. Enamel surrounds the coronal dentin, projects to the roots and is present as parallel inner laminae in buccolingual direction. The dentin is located among the enamel laminae and surrounds the pulp horns. The cementum is located internally to the enamel laminae. On the lingual surface, the cementum and dentin are the outer elements.

Anatomical and histological characteristics of teeth in agouti (Dasyprocta prymnolopha Wagler, 1831)

The agouti species Dasyprocta prymnolopha (D. prymnolopha) is a medium-sized rodent, diurnal, and characteristic of northeastern Brazil, south of the Amazon. Several studies have been made on these rodents. However, there is a lack of analysis of masticatory system, in particular morphology of the teeth. Thus, this research seeks to describe anatomical and histological aspects of the agouti teeth. For this purpose, we used adult agouti, in which measurements and descriptions of teeth and dental tissues were made. It was observed that the dental arch of D. prymnolopha comprises of twenty teeth, evenly distributed in the upper and lower arch, being inferior teeth larger than their corresponding higher. The incisors are larger, and between the posterior premolars and molars, there is a gradual increase in length in the anterior-posterior arch. In microscopic examination, a prismatic appearance was observed consisting of enamel prisms arranged in different directions, behind the enamel and dentin with standard tubular dentinal tubules with variable diameter and far between, also showing a sinuous path from the inner portion to the junction with more superficial enamel. Morphological analysis of dental tissues showed that an enamel with structural organization adapted to the act of chewing and high impact dentin compatible with standard tubular function resilience and mechanical damping of masticatory forces, as found in larger animals, confirming the understanding of eating habits that define much of its ecological functions within the ecosystem they inhabit.

Ghost protein damage by peroxynitrite and its protection by melatonin

We have studied the effect of peroxynitrite (ONOO-) on the membrane cytoskeleton of red blood cells and its protection by melatonin. Analysis of the protein fraction of the preparation by SDS-PAGE revealed a dose-dependent (0-600 µM ONOO-) disappearance at pH 7.4 of the main proteins: spectrin, band 3, and actin, with the concomitant formation of high-molecular weight aggregates resistant to reduction by ß-mercaptoethanol (2%) at room temperature for 20 min. These aggregates were not solubilized by 8 M urea. Incubation of the membrane cytoskeleton with ONOO- was characterized by a marked depletion of free sulfhydryl groups (50% at 250 µM ONOO-). However, a lack of effect of ß-mercaptoethanol suggests that, under our conditions, aggregate formation is not mediated only by sulfhydryl oxidation. The lack of a protective effect of the metal chelator diethylenetriaminepentaacetic acid confirmed that ONOO--induced oxidative damage does not occur only by a transition metal-dependent mechanism. However, we demonstrated a strong protection against cytoskeletal alterations by desferrioxamine, which has been described as a direct scavenger of the protonated form of peroxynitrite. Desferrioxamine (0.5 mM) also inhibited the loss of tryptophan fluorescence observed when the ghosts were treated with ONOO-. Glutathione, cysteine, and Trolox® (1 mM), but not mannitol (100 mM), were able to protect the proteins against the effect of ONOO- in a dose-dependent manner. Melatonin (0-1 mM) was especially efficient in reducing the loss of spectrin proteins when treated with ONOO- (90% at 500 µM melatonin). Our findings show that the cytoskeleton, and in particular spectrin, is a sensitive target for ONOO-. Specific antioxidants can protect against such alterations, which could seriously impair cell dynamics and generate morphological changes.

Ghost recon : näkymättömyyden tilat Terrence Malickin elokuvassa Veteen piirretty viiva

Teemanumero: Terrence Malick.

Unequal Teeth Widths for Torque Ripple Reduction in Permanent Magnet Synchronous Machines With Fractional-Slot Non-Overlapping Windings

Permanent magnet synchronous machines with fractional-slot non-overlapping windings (FSPMSM), also known as tooth-coil winding permanent magnet synchronous machines (TCW PMSM), have been under intensive research during the latest decade. There are many optimization routines explained and implemented in the literature in order to improve the characteristics of this machine type. This paper introduces a new technique for torque ripple minimization in TCW PMSM. The source of torque harmonics is also described. The low order torque harmonics can be harmful for a variety of applications, such as direct drive wind generators, direct drive light vehicle electrical motors, and for some high precision servo applications. The reduction of the torque ripple harmonics with the lowest orders (6th and 12th) is realized by machine geometry optimization technique using finite element analysis (FEA). The presented optimization technique includes the stator geometry adjustment in TCW PMSMs with rotor surface permanent magnets and with rotor embedded permanent magnets. Influence of the permanent magnet skewing on the torque ripple reduction and cogging torque elimination was also investigated. It was implemented separately and together with the stator optimization technique. As a result, the reduction of some torque ripple harmonics was attained.