Study of metals transfer from environment using teeth as biomonitor

We investigated chronic incorporation of metals in individuals from poor families, living in a small, restrict and allegedly contaminated area in Sao Paulo city, the surroundings of the Guarapiranga dam, responsible for water supply to 25% of the city population. A total of 59 teeth from individuals 7 to 60 years old were collected. The average concentrations of Pb, Cd, Fe, Zn, Mn, Ni and Cr were determined with an Atomic Absorption Spectrophotometer. The concentrations of all metals as function of the individuals` age exhibited a remarkable similarity: peaks between 7 and 10 years and sharply decreasing at higher ages, which could be attributed to alimentary habits and persistence to metals exposure all along the individuals` life span. From all the measured metals, lead and cadmium were a matter of much more concern since their measured values are close to the upper limits of the world wide averages. (C) 2009 Elsevier Ltd. All rights reserved.

Study of environmental burden of lead in children using teeth as bioindicator

The south region of Sao Paulo city hosts the Guarapiranga dam, responsible for water supply to 25% of the city population. Their surroundings have been subject to intense and irregular occupation by people from very low socioeconomics classes. Measurements undertaken on sediment and particulate materials in the dam revealed concentrations of lead. copper, zinc and cadmium above internationally accepted limits. Epidemiological and toxicological studies undertaken by the World Health Organization in individuals exhibiting lead concentrations in blood, near or below the maximum recommended (10 mu g dl(-1)), surprisingly revealed that toxic effects are more intense in individuals belonging to low socioeconomics classes. Motivated by these facts, we aimed at the investigation of chronic incorporation of lead. as well as the use of our BIOKINETICS code, which is based on an accepted ICRP biokinetics model for lead, in order to extrapolate the results from teeth to other organs. The focus of our data taking was children from poor families, living in a small, restrict and allegedly contaminated area in Sao Paulo city. Thus, a total of 74 human teeth were collected. The average concentration of lead in teeth of children 5 to 10 years old was determined by means of a high-resolution inductively coupled plasma mass spectrometer (ICP-MS). For standardization of the measurements, an animal bone certified material (H-Animal Bone), from the International Atomic Energy Agency, was analyzed. The amount of lead in children living in the surroundings of the dam, was approximately 40% higher than those from the control region, and the average lead concentration was equal to 1.3 mu g g(-1) approximately. Grouping the results in terms of gender, tooth type and condition, it was concluded that a carious molar of boys is a much more efficient contamination pathway for lead, resulting in concentrations 70% higher than in the control region. We also inferred the average concentrations of lead in other organs of these children, by making use of our BIOKINETIC code. (C) 2008 Elsevier Ltd. All rights reserved.

Evaluation of uranium incorporation from contaminated areas using teeth as bioindicators - a case study

The Southwest region of the Bahia state in Brazil hosts the largest uranium reserve of the country (100 kton in uranium, only), plus the cities of Caetite, Lagoa Real and Igapora. In this work, aim was at the investigation of uranium burdens on residents of these cities by using teeth as bioindicators, as a contribution for possible radiation protection measures. Thus, a total of 41 human teeth were collected, plus 50 from an allegedly uranium free area (the control region). Concentrations of uranium in teeth from residents of 5- to 87-y old were determined by means of a high-resolution inductively coupled plasma mass spectrometer (ICP-MS). The highest uranium concentration in teeth was measured from samples belonging to residents of Caetite (median equal to 16 ppb). Assuming that the uranium concentrations in teeth and bones are similar within 10-20% (for children and young adults), it concluded that uranium body levels in residents of Caetite are at least one order of magnitude higher than the worldwide average. This finding led to conclude that daily ingestion of uranium, from food and water, is equally high.

Cearania heterophylla gen. nov et sp nov., a fossil gymnosperm with affinities to the Gnetales from the Early Cretaceous of northern Gondwana

Vegetative and fertile shoots of a shrub-like seed plant from the late Aptian Crato Formation of Brazil are described as Cearania heterophylla Kunzmann, Mohr and Bernardes-de-Oliveira, gen. nov. et sp. nov. Anatomical details of the axes, epidermal features and separate ovulate and pollen producing organs indicate the gymnospermous nature of this plant. The vascular tissue of the axes includes tracheids with bordered pits and fiber tracheids. Vegetative shoots comprising at least three branching orders bear opposite-decussately arranged ovate to lanceolate, dorsiventrally flattened, parallelodromous, rather thick leaves that vary tremendously in size. The amphistomatic leaves bear (brachy-)paracytic stomatal complexes arranged in simple longitudinal files. The ovulate structure is interpreted as a terminally attached single globular ovule/seed surrounded by at least five to six lanceolate bracts. A terminally attached pollen-cone like structure grows on a lateral leafy shoot. The unusual character combination may indicate that the fossils belong to a hitherto unknown group with affinities to ephedroid Gnetales. Sterile shoots formerly often described as Podozamites, Nageiopsis or Lilites that are at least partly congeneric with C. heterophylla Kunzmann, Mohr and Bernardes-de-Oliveira, gen. nov. et sp. nov. had a wide geographic distribution during the Early Cretaceous. (C) 2009 Elsevier B.V. All rights reserved.

Bacteriologic investigation of the effects of sodium hypochlorite and chlorhexidine during the endodontic treatment of teeth with apical periodontitis

SIQUEIRA JR. et al. Bacteriologic investigation of the effects of sodium hypochlorite and chlorhexidine during the endodontic treatment of teeth with apical periodontitis. Oral Surg. Oral Med. Oral Pathol. Oral Radiol. Endod., v. 104, n. 1, p. 122-130, 2007.

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

Os dentes de cutias (Dasyprocta azarae) foram descritos macroscopicamente para fornecer informações sobre um dos maiores roedores das Américas. Radiografias foram realizadas em seis cabeças, e os dentes foram descritos. O esmalte envolve a dentina coronal e se projeta até a raiz e é presente como lâminas dispostas paralelamente em direção vestíbulolingual. A dentina é localizada entre as lâminas do esmalte e envolve os cornos pulpares. O cemento é localizado internamente às lâminas de esmalte. Na superfície lingual, o cemento e a dentina são os elementos mais externos.

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

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Short-term vs long-term calcium hydroxide therapy after immediate tooth replantation: a histomorphometric study in monkey's teeth

Endodontic treatment is an important step of tooth replantation protocols, but the ideal moment for definitive obturation of replanted teeth has not yet been established. In this study, a histomorphometric analysis was undertaken to evaluate the repair process on immediate replantation of monkeys teeth after calcium hydroxide (CH) therapy for 1 and 6 months followed by root canal filling with a CH-based sealer (Sealapex (R)). The maxillary and mandibular lateral incisors of five female Cebus apella monkeys were extracted, kept in sterile saline for 15 min, replanted and splinted with stainless steel orthodontic wire and composite resin for 10 days. In Group I (control), definitive root canal filling was performed before tooth extraction. In Groups II and III, CH therapy started after removal of splint, and definitive root canal filling was performed 1 and 6 months later, respectively. The animals were euthanized 9 months after replantation, and specimens were processed for histomorphometric analysis. In all groups, epithelial attachment occurred at the cementoenamel junction or very close to this region; the areas of resorption on root surface had small extension and depth and were repaired by newly formed cementum; and the periodontal ligament was organized. Statistical analysis of the scores obtained for the histomorphometric parameters did not show any statistically significant difference (P = 0.1221) among the groups. The results suggests that when endodontic treatment is initiated 10 days after immediate replantation and an antibiotic regimen is associated, definitive root canal filling can be performed after a short-term CH therapy.

Healing process of incisor teeth of diabetic rats replanted after storage in milk

Several local factors that influence the healing process of replanted teeth have been investigated. However, it remains unclear how systemic alterations, such as diabetes mellitus, affect the prognosis of these cases. The purpose of this study was to evaluate the healing process of incisors of non-controlled diabetic rats replanted after storage in bovine long shelf-life (UHT) whole milk. Thirty-two rats were randomly assigned to receive an endovenous injection of either citrate buffer solution (group I - control; n = 16) or streptozotocin dissolved in citrate buffer solution to induce diabetes (group II; n = 16). After confirmation of the diabetic status by analysis of the glycemic levels, the maxillary right incisor of each animal was extracted and immersed in milk for 60 min. The root canals of teeth were then instrumented, and were filled with a calcium hydroxide-based dressing and replanted into their sockets. All animals received systemic antibiotic and were killed by anesthetic overdose 10 and 60 days after replantation. The specimens containing the replanted teeth were removed, fixed, decalcified, and embedded in paraffin. Semi-serial 6-mu m-thick sections were obtained and stained with hematoxylin and eosin for histologic and histometric analyses. The results showed that the connective tissue adjacent to the root surface was less organized in the diabetic animals than in the control animals in both periods; the root dentin was less severely affected by root resorption in the diabetic rats; there were no significant differences between the control and diabetic groups regarding the occurrence of replacement resorption and inflammatory resorption.

Microscopic evaluation of induced tooth movement in traumatized teeth: an experimental study in rats

The clinical management of orthodontic patients with dental trauma before or during the treatment is mainly founded on clinical experience, expert opinions, and individual case reports. It is proposed in the literature that teeth sustaining mild trauma with minor damage to the periodontium (e.g. subluxation) should be followed for a period of time before being subjected to orthodontic forces. A minimum period of 3 months has been proposed. In this study, we used an animal model to investigate whether shorter observation periods could be established in case of mild trauma. The periradicular region of rat molars was examined microscopically to determine the biological events of tooth movement started 15 and 30 days after intentional subluxation using an experimental method to induce dentoalveolar trauma. Thirty adult male Wistar rats were assigned to 6 groups (n = 5): Group 1 (control no trauma/orthodontic movement); Group 2: the animals received an orthodontic device and were sacrificed after 7 days; Groups 3 and 4: dentoalveolar trauma (subluxation) was experimentally induced by the application of an axial force of 900 cN on the occlusal surface of the maxillary right first molar, and the animals were sacrificed after 22 and 37 days, respectively; and Groups 5 and 6: 15 and 30 days, respectively, after force application, an orthodontic device was installed and the rats were sacrificed 7 days later. In G5 and G6, the periodontal ligament and pulp tissue were rich in cellular elements and blood vessels, the alveolar bone was preserved, and the root surface presented only very small areas of surface resorption (cementum), maintaining the characteristics of normality. In conclusion, the microscopic alterations in the gingival and periodontal tissues in response to an experimentally induced mild dentoalveolar trauma simulating subluxation were not sufficient to contraindicate starting the orthodontic movement 15 and 30 days after trauma.

Use of a cyanoacrylate ester adhesive for splinting of replanted teeth

This paper reports a case of tooth replantation in which the splinting was performed with stainless steel orthodontic wire and a widely marketed brand of quick-setting cyanoacrylate ester adhesive (Super Bonder((R))). The long-term clinical and radiographic success of the case reported in this paper indicates that the splinting technique using a quick-setting cyanoacrylate ester adhesive may be a feasible option for making a rapid, simple and efficient contention of replanted teeth in situations where the routinely used materials are not readily available.

Recovering the function and esthetics of fractured teeth using several restorative cosmetic approaches. Three clinical cases

The teeth most commonly affected by trauma are the maxillary central incisors. The most frequent types of traumatic dental injuries to permanent teeth are enamel fractures, enamel and dentine fractures, and enamel and dentine fractures with pulp involvement. This article describes three clinical cases with different levels of traumatized maxillary incisors and several cosmetic approaches for recovery of the esthetics and the masticatory function, as well as the social/psychological aspects of treatment. All cases involved young adult men. The three clinical cases involve dentin and enamel fractures, dentin and enamel fractures with pulp exposure, and dentin and enamel fractures with pulp exposure associated with root fracture. The cosmetic treatments used to resolve fractures were direct composite resin by layering technique, indirect all-ceramic restorations (laminate veneer and ceramic crowns over the teeth), and immediate implant after extraction followed by immediate loading (ceramic abutments with ceramic crown over implant). In all three cases, excellent functional and esthetic results were achieved by use of these treatment modalities. The patients were very satisfied with the results.

Effect of calcium hydroxide-based materials on periapical tissue healing and orthodontic root resorption of endodontically treated teeth in dogs

This study evaluated periapical tissue healing and orthodontic root resorption of endodontically treated teeth sealed with calcium hydroxide in dogs. The sample consisted of three contralateral pairs of maxillary incisors and two contralateral pairs of mandibular incisors in each of two dogs using a split mouth design. After biomechanical preparation of the teeth in the first group (n = 10), a Ca(OH)(2) dressing was placed for 14 days before root canal filling with Ca(OH)(2)-based sealer (Sealapex) and gutta-percha points. In the second group (n = 10), root canals were obturated immediately after the mechanical preparation with gutta-percha points and zinc oxide and eugenol (ZOE)-based sealer (Endofill). After completion of endodontic treatment, the teeth were moved with an orthodontic appliance with a calibrated force of 200 g, reactivated every 21 days. After 105 days, the animals were killed and the teeth were removed upon completion of active treatment, without a period of recovery, and prepared for histomorphological analysis. All sections of each tooth were graded subjectively on a scale from one to four to obtain the average of the 16 histomorphological parameters analysed. Evaluation of the differences between the two treatment protocols was made with Mann-Whitney U-test. It was observed that the teeth treated with Ca(OH)(2)-based materials provided better outcomes (P = 5%), with complete repair of all root resorption areas, high rate of biological closure of the main canal and apical accessory canals by newly formed cementum, less intense and extensive chronic inflammatory infiltrate, and better organization of the periodontal ligament. Under the tested conditions, Ca(OH)(2)-based materials had a favourable action on periapical tissue healing and repair of orthodontic root resorption in endodontically treated dogs' teeth.

Propolis as storage media for avulsed teeth: microscopic and morphometric analysis in rats

The maintenance of the avulsed teeth in appropriate media for preserving the cellular viability has been important for repairing the periodontal ligament and preventing the root resorption after tooth reimplantation. Propolis is a substance capable of preserving cellular viability. This study aimed to analyze the propolis substance as a storage media for maintaining the avulsed teeth, besides to determine the ideal time period for keeping the tooth inside it. Thus, 60 maxillary right central incisors of rats were extracted and divided into five groups. In groups I and II, teeth were kept in propolis for 60 min and 6 h, respectively; in group III, teeth were kept in milk for 6 h; in group IV, teeth were kept dry for 60 min; and in group V, they were immediately reimplanted. All teeth had their root canals filled with calcium hydroxide paste. Following, teeth were reimplanted in their sockets. After 15 and 60 days, animals were killed and the obtained samples were processed in laboratory for microscopic and morphometric analyzing. The results showed that the occurrence of inflammatory resorption, dental ankylosis and the formation of the connective tissue parallel to the root surface were similar among groups. It could be verified a greater occurrence of replacement resorption in group IV when comparing to other groups. In groups I and IV, the presence of periodontal ligament-like connective tissue was substantially smaller than the other groups. Regarding to the cementum amount over the root, it could be observed that this was present in smaller amount in groups I and IV. Group II was similar to groups III and IV. Therefore, according to the results of this study, the use of propolis as a storage media for maintaining avulsed teeth could be highlighted, and the 6-h period was more appropriate than the 60-min period.

Periodontal and Prosthetic Biologic Considerations to Restore Biological Width in Posterior Teeth

\ The biologic width is an essential dental space that always needs to be maintained to ensure periodontal health in any dental prosthetic restorations. An iatrogenic partial fixed prosthesis constructed in lower posterior teeth predisposed the development of subgingival caries, which induced violation of the biologic width in involved teeth, resulting in an uncontrolled inflammatory process and periodontal tissue destruction. This clinical report describes a periodontal surgical technique to recover a violated biologic width in lower posterior teeth, by crown lengthening procedure associated with free gingival graft procedure, to ensure the possibility to place a modified partial fixed prosthesis in treated area. The procedure applied to recover the biologic width was crown lengthening with some modifications, associated with modified partial fixed prosthesis to achieve health in treated area. The modified techniques in both surgical and prosthetic procedures were applied to compensate the contraindications to recover biologic width by osteotomy in lower posterior teeth. The result, after 4 years under periodic control, seems to achieve the projected goal. Treating a dental diseased area is necessary to diagnose, eliminate, or control all etiologic factors involved in the process. When the traditional methods are not effective to recover destructed tissues, an alternative, compensatory, and adaptive procedure may be applied to restore the sequelae of the disease, applying a restorative method that respects the biology of involved tissues.