Diagnosis and treatment of extraction sockets in preparation for implant placement: report of three cases

This article addresses diagnostic parameters that should be assessed in the treatment of extraction sockets with dental implant placement by presenting three case reports that emphasize the relevance of the amount of remaining bone walls. Diagnosis was based on the analysis of clinical and radiographic parameters (e.g.: bone defect morphology, remaining bone volume, presence of infections on the receptor site). Case 1 presents a 5-wall defect in the maxillary right central incisor region with severe root resorption, which was treated with immediate implant placement. Cases 2 and 3 present, respectively, two- and three-wall bone defects that did not have indication for immediate implants. These cases were first submitted to a guided bone regeneration (GBR) procedure with bone graft biomaterial and membrane barriers, and the implants were installed in a second surgical procedure. The analysis of the preoperative periodontal condition of the adjacent teeth and bone defect morphology is extremely important because these factors determine the choice between immediate implant or GBR treatment followed by implant installation in a subsequent intervention.

O trauma raquimedular

A medula espinhal dos mamíferos adultos não permite a regeneração de axônios. Por razões ainda desconhecidas, as fibras neurais falham em cruzar o sítio da lesão, como se não houvesse crescimento, desde a primeira tentativa. Quais mecanismos poderiam explicar a perda da capacidade de regeneração? As cicatrizes formadas pelas células da glia seriam uma consequência da falha na regeneração ou a causa? Diversas linhas de evidência sugerem que a regeneração da medula espinhal seria impedida no sistema nervoso central pela ação de fatores locais no sítio da lesão, e que o sistema nervoso central não-lesado é um meio permissivo para o crescimento axonal, na direção de alvos específicos. Uma vez que os axônios são induzidos adequadamente a cruzar a lesão com o auxílio de implantes, fármacos ou células indiferenciadas, as fibras em regeneração podem encontrar a via específica e estabelecer conexões corretas. O que ainda não se sabe é que combinação de moléculas induz/inibe o potencial de regeneração do tecido e que mecanismos permitem aos neurônios formarem conexões específicas com os alvos com os quais são programados a fazer.

Alterações dimensionais do côndilo mandibular em indivíduos de 3 a 20 anos de idade usando tomografia computadorizada de feixe cônico: um estudo preliminar

INTRODUÇÃO: o exame de tomografia computadorizada de feixe cônico (TCFC) oferece excelente representação dos tecidos duros da articulação temporomandibular (ATM). OBJETIVO: investigar as alterações morfológicas do côndilo mandibular, da infância à idade adulta, utilizando a TCFC. MÉTODOS: um estudo transversal foi conduzido envolvendo 36 côndilos de 18 indivíduos com idades variando entre 3 e 20 anos. As imagens dos côndilos foram obtidas por meio do sistema i-CAT e medidas com uma ferramenta do programa específica para ATM, que permite cortes perpendiculares à cabeça do côndilo, com correção individual em função das diferenças angulares de cada um. As maiores distâncias nas vistas lateral e frontal foram consideradas tanto para os côndilos do lado direto como para os do lado esquerdo. RESULTADOS: a dimensão lateral do côndilo mandibular parece ser estabelecida de maneira precoce, sofrendo poucas alterações com o passar dos anos, enquanto a dimensão frontal tende a aumentar. Assimetrias entre o côndilo esquerdo e o direito foram comumente observadas; no entanto, tais diferenças não apresentaram significância estatística para as vistas lateral (P=0,815) e frontal (P=0,374). CONCLUSÕES: os côndilos apresentaram simetria com relação ao tamanho, sendo observado crescimento apenas na dimensão frontal Os resultados sugerem que a TCFC constitui-se numa ferramenta útil na mensuração e avaliação das dimensões condilares.

Diagnosis and root canal treatment in a mandibular premolar with three canals

This paper presents a case report of a left mandibular second premolar with three canals and three different apical foramina. A 39-year-old male patient presented to our clinic with pain in the mandibular left second premolar. Initially, pain was caused by cold stimulus and later was spontaneously. The intraoral clinical examination revealed a fractured amalgam restoration with occlusal caries. Percussion and cold (Endo-Frost) tests were positive. The radiographic examination showed the presence of two roots. The probable diagnosis was an acute pulpitis. After access cavity, it was observed remaining roof of the pulp chamber and mild bleeding in the tooth lingual area, indicating the possible presence of a third canal. The endodontic treatment was completed in a single session using Root ZX apex locator and K3 NiTi rotary system with surgical diameter corresponding to a .02/45 file in the three canals and irrigation with 1% sodium hypochlorite. The canals were obtured with gutta-percha cones and Sealer 26 using the lateral condensation technique. After 1 year of follow-up, the tooth was asymptomatic and periapical repair was observed radiographically. Internal alterations should be considered during the endodontic treatment of mandibular second premolars. The correct diagnosis of these alterations by the analysis of preoperative radiographs can help the location of two or more canals, thereby avoiding root therapy failure.

Immediate implants placed into infected sockets: a case report with 3-year follow-up

The esthetics and functional integrity of the periodontal tissue may be compromised by dental loss. Immediate implants became a viable option to maintain the periodontal architecture because of their anatomic compatibility with the dental socket and the possibility of eliminating local contamination. This article describes the procedure of immediate implant placement in the anterior maxilla replacing teeth with chronic periapical lesions, which were condemned due to endodontic lesions persisting after failed endodontic treatment and endodontic surgery, and discusses the relationship between the procedure and periapical lesions. Surgical removal of hopeless teeth 11, 12 and 21 was performed conservatively in such a way to preserve the anatomy and gingival esthetics. A second surgical access was gained at the apical level, allowing the debridement of the surgical chamber for elimination of the periapical lesion, visual orientation for setting of the implants and filling of the surgical chamber with xenogenous bovine bone graft. After this procedure, the bone chamber was covered with an absorbent membrane and the healing screws were positioned on the implants. Later, a provisional partial removable denture was installed and the implants were inserted after 6 months. After 3 years of rehabilitation, the implants present satisfactory functional and esthetic conditions, suggesting that immediate implant placement combined with guided bone regeneration may be indicated for replacing teeth lost due to chronic periapical lesions with endodontic failure history in the anterior maxilla.

Effects of detachment and repositioning of the medial pterygoid muscle on the growth of the maxilla and mandible of young rats

PURPOSE: To analyze the effects of detachment and repositioning of the medial pterygoid muscle on the growth of the maxilla and mandible of young rats through cephalometry. METHODS: Thirty one-month-old Wistar rats were used, distributed into three groups: experimental, sham-operated and control. In the experimental group, unilateral detachment and repositioning of the medial pterygoid muscle was performed. The sham-operated group only underwent surgical access, and the control group did not undergo any procedure. The animals were sacrificed at the age of three months. Their soft tissues were removed and the mandible was disarticulated. Radiographs of the skull in axial projection and the hemimandibles in lateral projection were obtained, and cephalometry was performed. The values obtained were subjected to statistical analyses among the groups and between the sides in each group. RESULTS: There were significant differences in the length of the mandible relative to the angular process in the experimental group and in the height of the mandibular body in the sham-operated group. CONCLUSION: The experimental detachment and repositioning of the medial pterygoid muscle during the growth period in rats affected the growth of the angle region, resulting in asymmetry of the mandible.

An experimental model for the study of craniofacial deformities

PURPOSE: To develop an experimental surgical model in rats for the study of craniofacial abnormalities. METHODS: Full thickness calvarial defects with 10x10-mm and 5x8-mm dimensions were created in 40 male NIS Wistar rats, body weight ranging from 320 to 420 g. The animals were equally divided into two groups. The periosteum was removed and dura mater was left intact. Animals were killed at 8 and 16 weeks postoperatively and cranial tissue samples were taken from the defects for histological analysis. RESULTS: Cranial defects remained open even after 16 weeks postoperatively. CONCLUSION: The experimental model with 5x8-mm defects in the parietal region with the removal of the periosteum and maintenance of the integrity of the dura mater are critical and might be used for the study of cranial bone defects in craniofacial abnormalities.

Juvenile idiopathic arthritis with involvement of the temporomandibular joint: the role of image examinations

PURPOSE: Juvenile idiopathic arthritis (JIA) has unknown etiology, and the involvement of the temporomandibular joint (TMJ) is rare in the early phase of the disease. The present article describes the use of computed tomography (CT) and magnetic resonance (MRI) images for the diagnosis of affected TMJ in JIA. CASE DESCRIPTION: A 12-year-old, female, Caucasian patient, with systemic rheumathoid arthritis and involvement of multiple joints was referred to the Imaging Center for TMJ assessment. The patient reported TMJ pain and limited opening of the mouth. The helical CT examination of the TMJ region showed asymmetric mandibular condyles, erosion of the right condyle and osteophyte-like formation. The MRI examination showed erosion of the right mandibular condyle, osteophytes, displacement without reduction and disruption of the articular disc. CONCLUSION: The disorders of the TMJ as a consequence of JIA must be carefully assessed by modern imaging methods such as CT and MRI. CT is very useful for the evaluation of discrete bone changes, which are not identified by conventional radiographs in the early phase of JIA. MRI allows the evaluation of soft tissues, the identification of acute articular inflammation and the differentiation between pannus and synovial hypertrophy.

Evaluation of DNA extraction protocols for Brucella abortus pcr detection in aborted fetuses or calves born from cows experimentally infected with strain 2308

The objective of the present study was to improve the detection of B. abortus by PCR in organs of aborted fetuses from infected cows, an important mechanism to find infected herds on the eradication phase of the program. So, different DNA extraction protocols were compared, focusing the PCR detection of B. abortus in clinical samples collected from aborted fetuses or calves born from cows challenged with the 2308 B. abortus strain. Therefore, two gold standard groups were built based on classical bacteriology, formed from: 32 lungs (17 positives), 26 spleens (11 positives), 23 livers (8 positives) and 22 bronchial lymph nodes (7 positives). All samples were submitted to three DNA extraction protocols, followed by the same amplification process with the primers B4 and B5. From the accumulated results for organ, the proportion of positives for the lungs was higher than the livers (p=0.04) or bronchial lymph nodes (p=0.004) and equal to the spleens (p=0.18). From the accumulated results for DNA extraction protocol, the proportion of positives for the Boom protocol was bigger than the PK (p<0.0001) and GT (p=0.0004). There was no difference between the PK and GT protocols (p=0.5). Some positive samples from the classical bacteriology were negative to the PCR and viceversa. Therefore, the best strategy for B. abortus detection in the organs of aborted fetuses or calves born from infected cows is the use, in parallel, of isolation by classical bacteriology and the PCR, with the DNA extraction performed by the Boom protocol.

Polyamine patterns in haploid and diploid tobacco tissues and in vitro cultures

The aim of this work was to determine PAs levels in pith tissues and callus cultures from haploid and diploid tobacco plants, explanted from the apical and basal regions of the stem. These explants were cultured in an RM-64 medium supplied with IAA and kinetin, under light or in the dark, during successive subcultures. PAs levels followed a basipetal decrease in diploid and an increase in haploid, pith tissues. A similar pattern of total PAs (free + conjugated) was observed for the callus of diploid and haploid plants maintained in the light, and for the haploid callus in the dark, whereas the diploid callus in the dark showed a constant increase in total PAs levels until the end of culture. The PA increase in the diploid callus in the dark was related to free Put levels increase. The ploidy status of the plants could express different PA gradients together with the plant pith and in vitro callus cultures.

Morpho-Anatomical Analysis of the Rhizome in Species of Scleria Berg. (Cyperaceae) from Serra do Cipó (MG)

Aspects related to the nature of stem thickening in monocotyledons have been the subject of many studies. Primary thickening has been attributed to the Primary Thickening Meristem (PTM). According to most authors, it gives rise, besides the adventitious roots, to the vascular tissues and part of the cortex. In other words, it has centripetal and centrifugal activity. For some authors, however, it gives rise only to the vascular system, and for others, only to part of the cortex. However, this work demonstrated that PTM corresponds to the pericycle in the meristematic phase or to the pericycle associated with the endodermis, also with meristematic activity. It was observed that the pericycle was responsible for the formation of the vascular system of the rhizome and of the adventitious roots; the endodermis gave rise to cell layers with radial disposition which comprised the inner portion of the stem cortex, and which corresponded to the region known as the derivatives of the meristematic endodermis (DME). A continuity was also demonstrated between the tissues of the stem and root in species of Scleria Berg. (Cyperaceae).

Morphology and anatomy of leaf miners in two species of Commelinaceae (Commelina diffusa Burm. f. and Floscopa glabrata (Kunth) Hassk)

In specialized literature, reports on anatomy of miners in host plants are few in number. These agents trigger excavations, or paths, by consumption of plant inner tissues by larvae of several insects. The aim of this work was to investigate leaf miner occurrence in Commelina diffusa (a cosmopolitan plant) and Floscopa glabrata (an amphibious plant) using anatomical techniques. The place where the plants were collected is subjected to seasonal floods, consequently both the species were exposed to the same weather conditions and seasonal floods. This study showed that members of Agromyzidae and Chironomidae families, which are Diptera endophytophagous larvae types, were responsible for the tunnels. Moreover, in Commelina diffusa Agromyzidae larvae were found, while in Floscopa glabrata three Chironomidae cephalic exuviae were found. The miners, as can be seen from anatomical studies, used only mesophyll parenchyma tissues for feeding, causing the formation of linear mines. In addition, in both the species, the epidermis and the medium-sized vascular units were kept intact, showing no structural modification, such as neoformation of tissues.

A importância do uso das células tronco para a saúde pública

Em 1999, as células-tronco foram eleitas "Scientific Breakthrough of the Year" (avanço científico do ano) pela revista Science¹. Naquele ano, foi demonstrado que células-tronco de tecidos adultos mantinham a capacidade de se diferenciar em outros tipos de tecidos. No ano anterior, as primeiras linhagens de células-tronco embrionárias humanas foram estabelecidas. Desde então, o número de artigos científicos sobre células-tronco vem crescendo exponencialmente, onde novos paradigmas são estabelecidos. Neste artigo, farei uma revisão da área de células-tronco com um foco especial em seu uso como agente terapêutico em doenças comuns como diabetes e cardiopatias. As células-tronco serão tratadas em dois grupos distintos: as embrionárias e as adultas. Enquanto o potencial de diferenciação das primeiras está bem caracterizado em camundongos e em humanos, seu uso em terapia celular e em pesquisa tem sido dificultado por questões de histocompatibilidade, segurança e ética. Em contraste, células-tronco adultas não apresentam estes empecilhos, apesar da extensão de sua plasticidade ainda estar sob investigação. Mesmo assim, diversos testes clínicos em humanos estão em andamento utilizando células-tronco adultas, principalmente derivadas da medula óssea. Discutirei ainda a importância de se trabalhar com as duas classes de células-tronco humanas de forma a se cumprir suas promessas terapêuticas.

Alveolar osseous defect in rat for cell therapy: preliminary report

PURPOSE: To study were to reproduce an alveolar bone defect model in Wistar rats to be used for testing the efficacy of stem cell therapies. Additionally, we also aimed to determine the osteogenesis process of this osseous defect in the 1 month period post-surgery. METHODS: The animals were randomly divided into two groups of 7 animals each. A gingivobuccal incision was made, and a bone defect of 28 mm² of area was performed in the alveolar region. Animals were killed at 2 weeks after surgery (n=7) and 4 weeks after surgery (n=7). RESULTS: The average area of the alveolar defect at time point of 2 weeks was 22.27 ± 1.31 mm² and the average area of alveolar defect at time point of 4 weeks was 9.03 ± 1.17 mm². The average amount of bone formation at time point of 2 weeks was 5.73 ± 1.31 mm² and the average amount of bone formation at time point of 4 weeks was 19 ± 1.17 mm². Statistically significant differences between the amount of bone formation at 2 weeks and 4 weeks after surgery were seen (p=0.003). CONCLUSION: The highest rate of ossification occurred mostly from 2 to 4 weeks after surgery. This observation suggests that 4 weeks after the bone defect creation should be a satisfactory timing to assess the potential of bone inductive stem cells to accelerate bone regeneration in Wistar rats.

Ant community richness and composition across a gradient from Eucalyptus plantations to secondary Atlantic Forest

Secondary forests and exotic tree plantations are expanding across tropical landscapes. However, our current understanding of the value of these human-dominated forest landscapes for invertebrate biodiversity conservation is still very poor. In this paper, we use the leaf-litter ant fauna to assess invertebrate diversity in one commercially managed Eucalyptus plantation (four years old), two abandoned plantations of different regeneration ages (16 and 31 years), and one neighboring secondary Atlantic Forest in Southeastern Brazil. There was a clear gradient in species richness from the secondary forest to the managed Eucalyptus plantation; richness and diversity peaked in secondary forest and in the older regenerating Eucalyptus plantation. Significantly more species were recorded in secondary forest samples than in Eucalyptus plantations, but Eucalyptus plantations had a similar level of richness. Furthermore, a non-metric multidimensional scaling analysis revealed clear differences in species composition between the younger managed Eucalyptus plantation (understory absent) and habitats with sub-developed or developed understory. Eucalyptus plantations were characterized by an assemblage of widespread, generalist species very different from those known to occur in core forest habitats of southeastern Brazil. Our results indicate that while older regenerating Eucalyptus plantations can provide habitat to facilitate the persistence of generalist ant species, it is unlikely to conserve most of the primary forest species, such as specialized predators, Dacetini predators, and nomadic species.