Impact of the adjacent bone on pseudarthrosis in mandibular reconstruction with fibula free flaps.

BACKGROUND: Mechanical and morphological factors have both been described to influence the rate of pseudarthrosis in mandibular reconstruction. By minimizing mechanical confounders, the present study aims to evaluate the impact of bone origin at the intersegmental gap on osseous union. METHODS: Patients were screened retrospectively for undergoing multi-segment fibula free flap reconstruction of the mandible including the anterior part of the mandible and osteosynthesis using patient-specific 3D-printed titanium reconstruction plates. Percentage changes in bone volume and width at the bone interface between the fibula/fibula and fibula/mandible at the anterior intersegmental gaps within the same patient were determined using cone-beam computed tomography (CBCT). Additionally, representative samples of the intersegmental zones were assessed histologically and using micro-computed tomography (µCT). RESULTS: The bone interface (p = 0.223) did not significantly impact the change in bone volume at the intersegmental gap. Radiotherapy (p < 0.001), time between CBCT scans (p = 0.006) and wound healing disorders (p = 0.005) were independent risk factors for osseous non-union. Preliminary analysis of the microstructure of the intersegmental bone did not indicate morphological differences between fibula-fibula and fibula-mandible intersegmental bones. CONCLUSIONS: The bone interface at the intersegmental gap in mandibular reconstruction did not influence long-term bone healing significantly. Mechanical and clinical properties seem to be more relevant for surgical success.

Patients ' perspectives on bone replacement materials in a German university hospital setting.

BACKGROUND: The challenges in developing new bone replacement materials and procedures reside not solely in technological innovation and advancement, but also in a broader patient therapy acceptance. Therefore, there is a need to assess patients' perspectives on the materials and approaches in use as well as the ones being developed to better steer future progress in the field. METHODS: A self-initiating cross-sectional questionnaire aimed at people seeking treatment at the university hospital environment of Charité Berlin was formulated. The survey contained 15 close-ended questions directed toward the participant's epidemiological profile, willingness, acceptance, and agreement to receive different bone replacement materials, as well as, worries about the post-surgical consequences that can arise post bone replacement surgery. Descriptive and categorical analysis was performed to compare the observed number of subjects, their profile and each related response (Pearson's chi-square test or Fischer's test, p < 0.05). RESULTS: A total of 198 people engaged with the questionnaire, most of them Millennials. Overall patients trusted scientifically developed biomaterials designed for bone replacement, as demonstrated by their willingness to participate in a clinical trial, their acceptance of alloplastic materials, and the none/few worries about the presence of permanent implants. The data revealed the preferences of patients towards autologous sources of cells and blood to be used with a biomaterial. The data have also shown that both generation and education influenced willingness to participate in a clinical trial and acceptance of alloplastic materials, as well as, worries about the presence of permanent implants and agreement to receive a material with pooled blood and cells. CONCLUSION: Patients were open to the implantation of biomaterials for bone replacement, with a preference toward autologous sources of blood and/or tissue. Moreover, patients are concerned about strategies based on permanent implants, which indicates a need for resorbable materials. The knowledge gained in this study supports the development of new bone biomaterials.

Uncovering the unique characteristics of the mandible to improve clinical approaches to mandibular regeneration.

The mandible (lower jaw) bone is aesthetically responsible for shaping the lower face, physiologically in charge of the masticatory movements, and phonetically accountable for the articulation of different phonemes. Thus, pathologies that result in great damage to the mandible severely impact the lives of patients. Mandibular reconstruction techniques are mainly based on the use of flaps, most notably free vascularized fibula flaps. However, the mandible is a craniofacial bone with unique characteristics. Its morphogenesis, morphology, physiology, biomechanics, genetic profile, and osteoimmune environment are different from any other non-craniofacial bone. This fact is especially important to consider during mandibular reconstruction, as all these differences result in unique clinical traits of the mandible that can impact the results of jaw reconstructions. Furthermore, overall changes in the mandible and the flap post-reconstruction may be dissimilar, and the replacement process of the bone graft tissue during healing can take years, which in some cases can result in postsurgical complications. Therefore, the present review highlights the uniqueness of the jaw and how this factor can influence the outcome of its reconstruction while using an exemplary clinical case of pseudoarthrosis in a free vascularized fibula flap.

Patient-specific miniplates versus patient-specific reconstruction plate: A biomechanical comparison with 3D-printed plates in mandibular reconstruction.

BACKGROUND: Patient-specific 3D-printed miniplates for free flap fixation in mandibular reconstruction were recently associated with enhanced osseous union. Higher mechanical strains resulting from these plates are discussed as reasons, but biomechanical studies are missing. This study aims to examine, whether patient-specific 3D-printed miniplates provide an increased interosteotomy movement (IOM) and lower stiffness compared with reconstruction plates. METHODS: Polyurethane (PU) mandible and fibula models (Synbone AG, Malans, Schweiz) were used to simulate mandibular reconstruction with a one segment fibula flap equivalent. Osteosynthesis was performed using either four patient-specific 3D-printed miniplates (3D-Mini) or one patient-specific 3D-printed reconstruction plate (3D-Recon). Mastication was simulated using cyclic dynamic loading with increasing loads until material failure or a maximum load of 1000 N. Continuous IOM recording was carried out using a 3D optical tracking system (ARAMIS, Carl Zeiss GOM Metrology, Braunschweig, Germany). FINDINGS: The averaged stiffness at a load of 100-300 N load did not differ between the groups (p = 0.296). There was a faster 1.0 mm vertical displacement in the 3D-Mini group (26 376 ± 14 190 cycles versus 44 817 ± 30 430 cycles, p = 0.018). The IOM were higher with miniplate fixation in the distal gap (p = 0.040). In the mesial gap, there was no significant difference between the groups (p = 0.160). INTERPRETATION: Fixation with patient-specific 3D-printed miniplates results in higher mechanical strains. Lower rates of pseudarthrosis, as seen in clinical studies, might be caused by this phenomenon. Surgeons should evaluate the primary use of 3D-printed miniplates in mandibular reconstruction due to advantages of intraoral plate removal alongside safe osteosynthesis.

Long-term in vivo observations show biocompatibility and performance of ZX00 magnesium screws surface-modified by plasma-electrolytic oxidation in Göttingen miniature pigs.

Bioabsorbable magnesium implants for orthopedic fixation of bone have recently become available for different fields of indication. While general questions of biocompatibility have been answered, tailoring suitable degradation kinetics for specific applications as well as long-term tissue integration remain the focus of current research. The aim of this study was the evaluation of the long-term degradation behavior and osseointegration of Mg-Ca-Zn (ZX00MEO) based magnesium implants with plasma-electrolytic oxidation (PEO) surface modification (ZX00MEO-PEO) in comparison to non-surface modified implants in vivo and in vitro. Besides a general evaluation of the biological performance of the alloy over a prolonged period, the main hypothesis was that PEO surface modification significantly reduces implant degradation rate and improves tissue interaction. In vitro, the microstructure and surface of the bioabsorbable screws were characterized by SEM/EDS, cytocompatibility and degradation testing facilitating hydrogen gas evolution, carried out following ISO 10993-5/-12 and ASTM F3268-18a/ASTM G1-03 (E1:2017). In vivo, screws were implanted in the frontal bone of Minipigs for 6, 12, and 18 months, following radiological and histomorphometric analysis. A slower and more uniform degradation and improved cytocompatibility could be shown for the ZX00MEO-PEO group in vitro. A significant reduction of degradation rate and enhanced bone formation around the ZX00MEO-PEO screws in vivo was confirmed. Proficient biocompatibility and tissue integration could generally be shown in vivo regardless of surface state. The tested magnesium alloy shows generally beneficial properties as an implant material, while PEO-surface modification further improves the bioabsorption behavior both in vitro and in vivo. STATEMENT OF SIGNIFICANCE: Devices from bioabsorbable Magnesium have recently been introduced to orthopedic applications. However, the vast degradation of Magnesium within the human body still gives limitations. While reliable in-vivo data on most promising surface treatments such as Plasma-electrolytic-Oxidation is generally scarce, long-time results in large animals are to this date completely missing. To overcome this lack of evidence, we studied a Magnesium-Calzium-Zinc-alloy with surface enhancement by PEO for the first time ever over a period of 18 months in a large animal model. In-vitro, surface-modified screws showed significantly improved cytocompatibility and reduction of degradation confirmed by hydrogen gas evolution testing, while in-vivo radiological and histological evaluation generally showed good biocompatibility and bioabsorption as well as significantly enhanced reduction of degradation and faster bone regeneration in the PEO-surface-modified group.

Scattering and phase-contrast X-ray methods reveal damage to glass fibers in endodontic posts following dental bur trimming.

OBJECTIVES: There is concern that the integrity of fiberglass dental posts may be affected by chairside trimming during treatment. We hypothesize that hard X-ray methods of phase contrast-enhanced micro-CT (PCE-CT) and synchrotron based X-ray refraction (SXRR) can reliably identify and help characterize the extent of damage. METHODS: Fiberglass posts were imaged both as manufactured and following trimming with a diamond bur. Each of the posts was imaged by SXRR and by PCE-CT. Datasets from PCE-CT were used to visualize and quantify 2D and 3D morphological characteristics of intact and of damage-affected regions caused by trimming. RESULTS: The SXRR images revealed fiber inhomogeneities from manufacturing with a significant increase in internal surfaces in sample regions corresponding to damage from trimming. PCE-CT volumes unveiled the micromorphology of single fibers in the posts and some damage in the trimmed area (e.g. fractures, splinters and cracks). Area, perimeter, circularity, roundness, volume and thickness of the glass fibers in the trimmed area were statistically different from the control (p < 0.01). SIGNIFICANCE: The integrity of single fibers in the post is critical for bending resistance and for long-term adhesion to the cement in the root canals. Damage to the fibers causes substantial structural weakening across the post diameter. Glass fragments produced due to contact with the dental bur may separate from the post and may significantly reduce bond capacity. The above mentioned synchrotron-based imaging techniques can further facilitate assessment of the structural integrity and the appearance of defects in posts (e.g. after mechanical load).

An Early Myeloma Bone Disease Model in Skeletally Mature Mice as a Platform for Biomaterial Characterization of the Extracellular Matrix.

Multiple myeloma (MM) bone disease is characterized by osteolytic bone tissue destruction resulting in bone pain, fractures, vertebral collapse, and spinal cord compression in patients. Upon initial diagnosis of MM, almost 80% of patients suffer from bone disease. Earlier diagnosis and intervention in MM bone disease would potentially improve treatment outcome and patient survival. New preclinical models are needed for developing novel diagnostic markers of bone structural changes as early as possible in the disease course. Here, we report a proof-of-concept, syngeneic, intrafemoral MOPC315.BM MM murine model in skeletally mature BALB/c mice for detection and characterization of very early changes in the extracellular matrix (ECM) of MM-injected animals. Bioluminescence imaging (BLI) in vivo confirmed myeloma engraftment in 100% of the animals with high osteoclast activity within 21 days after tumor cell inoculation. Early signs of aggressive bone turnover were observed on the outer bone surfaces by high-resolution microcomputed tomography (microCT). Synchrotron phase contrast-enhanced microcomputer tomography (PCE-CT) revealed very local microarchitecture differences highlighting numerous active sites of erosion and new bone at the micrometer scale. Correlative backscattered electron imaging (BSE) and confocal laser scanning microscopy allowed direct comparison of mineralized and nonmineralized matrix changes in the cortical bone. The osteocyte lacunar-canalicular network (OLCN) architecture was disorganized, and irregular-shaped osteocyte lacunae were observed in MM-injected bones after 21 days. Our model provides a potential platform to further evaluate pathological MM bone lesion development at the micro- and ultrastructural levels. These promising results make it possible to combine material science and pharmacological investigations that may improve early detection and treatment of MM bone disease.

The forgotten merits of GIC restorations: a systematic review.

OBJECTIVE: To reevaluate proven strengths and weakness of glass ionomer cements (GICs) and to identify agreement versus conflicting evidence in previous reports regarding the transition between GIC and the tooth, and the existence of an "interphase". MATERIALS AND METHODS: Relevant electronic databases (PubMed, Embase via Ovid and Medline via Web of science) were searched for publications of evidence relating to the transition zone at the GIC-tooth interphase. Studies were examined and grouped according to characteristics of GIC-tooth attachment area quantified by X-ray and optical microscopy techniques in 2D and 3D. RESULTS: Inclusion criteria comprised of in vitro studies that showed images of the conventional GIC-tooth substrate attachments using at least one of the following techniques: SEM, CLSM, or µCT. The search identified 419 studies, from which 33 were included. Ten studies demonstrated the existence of an interphase layer and five studies quantified the layer thickness (1-15 µ). Twenty-nine publications studied different failure modes of the GIC-tooth interphase. Eleven studies described discontinuities inside the GIC bulk. CONCLUSION: The GIC-tooth interphase attributes evolve with time. Good attachment is evident even under compromised surface preparation. The GIC-tooth attachment area is resistant to acidic dissolution as compared to both tooth and GIC bulk. In general, studies revealed mostly intact GIC-tooth interphases with only some cracked interphases. CLINICAL SIGNIFICANCE: GIC bonds to the tooth structure and forms an acid resistant attachment zone that might enhance caries inhibition. Due to fluoride release and ease of use, GIC provides a cost effective treatment, ideal for low income or high caries populations.

Type 1 diabetes mellitus effects on dental enamel formation revealed by microscopy and microanalysis.

BACKGROUND: Type 1 diabetes mellitus (T1DM) largely affects children, occurring therefore at the same period of deciduous and permanent teeth development. The aim of this work was to investigate birefringence and morphology of the secretory stage enamel organic extracellular matrix (EOECM), and structural and mechanical features of mature enamel from T1DM rats. METHODS: Adult Wistar rats were maintained alive for a period of 56 days after the induction of experimental T1DM with a single dose of streptozotocin (60 mg/kg). After proper euthanasia of the animals, fixed upper incisors were accurately processed, and secretory stage EOECM and mature enamel were analyzed by transmitted polarizing and bright field light microscopies (TPLM and BFLM), energy-dispersive x-ray (EDX) analysis, scanning electron microscopy (SEM), and microhardness testing. RESULTS: Bright field light microscopies and transmitted polarizing light microscopies showed slight morphological changes in the secretory stage EOECM from diabetic rats, which also did not exhibit statistically significant alterations in birefringence brightness when compared to control animals (P > .05). EDX analysis showed that T1DM induced statistically significant little increases in the amount of calcium and phosphorus in outer mature enamel (P < .01) with preservation of calcium/phosphorus ratio in that structure (P > .05). T1DM also caused important ultrastructural alterations in mature enamel as revealed by SEM and induced a statistically significant reduction of about 13.67% in its microhardness at 80 µm from dentin-enamel junction (P < .01). CONCLUSIONS: This study shows that T1DM may disturb enamel development, leading to alterations in mature enamel ultrastructure and in its mechanical features.

Bisphosphonates: Pharmacokinetics, bioavailability, mechanisms of action, clinical applications in children, and effects on tooth development.

Bisphosphonates (BPs) avidly bind to calcium crystals and inhibit osteoclastic bone resorption, making them useful for treatment of skeletal disorders such as osteoporosis, Paget's disease, osteogenesis imperfecta and metastatic bone diseases. BPs therapeutically act by causing toxic effects on osteoclasts or interfering with specific intracellular pathways in those cells. BPs that possess nitrogen in their composition are called nitrogen-containing BPs (NBPs) and include alendronate, pamidronate, risedronate, ibandronate, and zoledronate. Simple BPs or non-NBPs do not have nitrogen in their composition, include etiodronate and clodronate, and were the first to be tested in animals and clinically used. Because BPs may be administered to pregnant women or children during deciduous and permanent teeth development, it is expected that they might disturb tooth eruption and development. A review of current literature on pharmacokinetics, bioavailability, mechanisms of action, and clinical applications of BPs in children, and their effects on tooth eruption and development is presented.

Characterization of surface topography and chemical composition of mini-implants

Abstract Aim : To assess the surface topography and chemical composition of three brands of as-received mini-implants (SIN(r), Morelli(r), and Conexao(r)). Methods: Twelve mini-implants of each brand were analyzed by scanning electron microscopy and energy dispersive X-ray (EDX). Results: There was no significant differences among SIN(r), Morelli(r), and Conexao(r) mini-implants comparing their surface topography by visualization of SEM micrographs and analysis of scores. The EDX analysis showed statistically significant difference among them for the amount of Ti, Al and V. Miniimplants SIN(r)presented also N and O in their composition. Conclusions: In conclusion, the miniimplants Morelli(r), SIN(r) and Conexao(r) presented Ti as main component of the alloy. Remaining components, such as Al and V, were also observed in all the analyzed brands, with differences among them. Only SIN(r)mini-implants presented N and O. As far as surface topography is concerned, there are no differences among the three brands of mini-implants.

Coleta e cultura de células-tronco obtidas da polpa de dentes decíduos: técnica e relato de caso clínico / Collection and culture of stem cells derived from dental pulp of deciduous teeth: technique and clinical case report

INTRODUÇÃO: as células-tronco (CT) possuem capacidade de induzir a regeneração tecidual e, portanto, apresentam um potencial terapêutico. Assim como a medula óssea e o cordão umbilical, a polpa dentária é uma das fontes disponíveis de CT. O seu fácil acesso e o fato de os dentes decíduos não serem órgãos vitais, que normalmente são descartados após a esfoliação, provêm um atrativo para testes de segurança e viabilidade terapêutica dessas células. OBJETIVOS: descrever a coleta, o isolamento e o cultivo de CT obtidas da polpa de dentes decíduos, assim como a sua caracterização por meio de citometria de fluxo e da indução da diferenciação em linhagens osteogênica e adipogênica. MÉTODOS: as CT foram obtidas de forma relativamente simples e apresentaram boa capacidade proliferativa, mesmo a partir de pouca quantidade de tecido pulpar. RESULTADOS: a análise por citometria de fluxo confirmou as características de CT mesenquimais, com baixos níveis de expressão dos antígenos CD34 e CD45, que são marcadores de células hematopoiéticas, e altos níveis de expressão dos antígenos CD105, CD166, CD90 e CD73, que são marcadores de CT mesenquimais. A plasticidade das células foi confirmada pela identificação de depósitos de cálcio nas culturas que receberam meio osteogênico, e de acúmulo lipídico intracelular nas culturas que receberam meio adipogênico. CONCLUSÕES: as CT de dentes decíduos têm um potencial promissor de aplicação em regeneração tecidual. Sendo assim, é importante difundir entre os cirurgiões-dentistas o conhecimento sobre a existência e as características dessa fonte de CT, discutindo a técnica utilizada, suas limitações e possíveis indicações.

INTRODUCTION: Stem cells (SCs) are capable of inducing tissue regeneration and are, therefore, potentially therapeutic. Similarly to bone marrow and umbilical cords, dental pulp is one of the available sources of SCs. The fact that these cells are easily accessible and that deciduous teeth are not vital organs, and are normally discarded after exfoliation, make them particularly attractive for use in safety and viability tests. OBJECTIVE: To describe the collection, isolation and culture of SCs obtained from the pulp of deciduous teeth as well as their characterization by flow cytometry, and the induction of differentiation into osteogenic and adipogenic lineages. METHODS: SCs were obtained in a relatively straightforward manner and showed good proliferative capacity, even from a small amount of pulp tissue. RESULTS: Analysis by flow cytometry confirmed the characteristics of mesenchymal SCs with low expression of CD34 and CD45 antigens, which are markers for hematopoietic cells, and high levels of expression of CD105, CD166, CD90 and CD73 antigens, which are markers for mesenchymal SCs. Cell plasticity was confirmed by identifying calcium deposits in cultures that received osteogenic medium, and intracellular lipid accumulation in adipogenic cultures that received adipogenic medium. CONCLUSIONS: SCs collected from deciduous teeth show promising potential for application in tissue regeneration. Therefore, it is important that knowledge about the existence and characteristics of this source of stem cells be disseminated among dentists and that the technique, its limitations and possible indications are highlighted and discussed.

Influence of laser photobiomodulation upon connective tissue remodeling during wound healing.

The modulation of collagen fibers during experimental skin wound healing was studied in 112 Wistar rats submitted to laser photobiomodulation treatment. A standardized 8mm-diameter wound was made on the dorsal skin of all animals. In half of them, 0.2ml of a silica suspension was injected along the border of the wound in order to enhance collagen deposition and facilitate observation. The others received saline as vehicle. The treatment was carried out by means of laser rays from an aluminum-gallium arsenide diode semiconductor with 9mW applied every other day (total dose=4J/cm2) on the borders of the wound. Tissue sections obtained from four experimental groups representing sham-irradiated animals, laser, silica and the association of both, were studied after 3, 7, 10, 15, 20, 30 and 60 days from the laser application. The wounded skin area was surgically removed and submitted to histological, immunohistochemical, ultrastructural, and immunofluorescent studies. Besides the degree and arrangement of collagen fibers and of their isotypes, the degree of edema, the presence of several cell types especially pericytes and myofibroblasts, were described and measured. The observation of Sirius-red stained slides under polarized microscopy revealed to be of great help during the morphological analysis of the collagen tissue dynamic changes. It was demonstrated that laser application was responsible for edema regression and a diminution in the number of inflammatory cells (p<0.05). An evident increase in the number of actin-positive cells was observed in the laser-treated wounds. Collagen deposition was less than expected in silica-treated wounds, and laser treatment contributed to its better differentiation and modulation in all irradiated groups. Thus, laser photobiomodulation was able to induce several modifications during the cutaneous healing process, especially in favoring newly-formed collagen fibers to be better organized and compactedly disposed.

Células-tronco em odontologia / Stem cells in Dentistry

INTRODUÇÃO: existe um grande interesse no desenvolvimento de técnicas para a manipulação de células-tronco, no intuito de instituirem-se tratamentos restauradores de tecidos e órgãos. Para que a bioengenharia seja eficaz, faz-se necessária a presença de três fatores: as próprias células-tronco, uma matriz extracelular e fatores de crescimento. Existem inúmeros fatores de crescimento envolvidos no desenvolvimento do órgão dentário. Por isso pesquisadores ainda não foram capazes de formar um órgão completo, embora existam diversos estudos evidenciando a formação de esmalte e dentina a partir de células-tronco isoladas da polpa dentária. Recentemente, também foram isoladas células-tronco da polpa dos dentes decíduos. Sabe-se que estas células são altamente proliferativas, sendo de grande importância para o cirurgião-dentista o conhecimento do seu comportamento biológico e técnicas de obtenção. OBJETIVO: este estudo teve como objetivo realizar uma revisão de literatura acerca das atuais tendências das pesquisas com células-tronco na Odontologia, além de discorrer sobre os fatores implicados para o sucesso na utilização prática dessas células.

INTRODUCTION: there is great interest in developing techniques for manipulation of stem cells for the use in restoring organs and tissues. The effectiveness of bioengineering is based on the existence of stem cells, an extra cellular matrix and growth factors. Innumerous growth factors are involved in the development of dental organs, and this complexity of factors makes it extremely difficult to grow a complete organ, even though there are multiple essays reporting the formation of enamel and dentin from isolated stem cell, originating from dental pulp tissues. More recently, deciduous teeth have been used to extract stem cells from their pulp tissues. We know that these cells are highly proliferate. The recognition of the biological behavior of these cells and techniques used to isolate them is of great interest to dentists. AIM: the aim of this study was to review the current trends of research with stem cells in Dentistry and the factors implied for their practical and successful use.

[Dental fluorosis in schoolchildren 12 and 15 years of age in Salvador, Bahia, Brazil, in 2001 and 2004]. / Fluorose dentária em escolares de 12 e 15 anos de idade. Salvador, Bahia, Brasil, nos anos 2001 e 2004.

This article compares the results of two surveys in Salvador, Bahia State, Brazil, on prevalence and severity of dental fluorosis in 12 and 15-year-olds. The article discusses the survey methodologies in relation to their sampling process, calibration of examiners, and data collection procedures, comparing the resulting differences using chi-square and 95% confidence intervals obtained with the Dean index. A total of 3,313 adolescents 12 and 15 years of age were analyzed in 2001 and 1,032 in 2004. Both surveys used examiner calibration, and the samples were population-based. In the second survey there were a higher proportion of students from public schools for both ages, as compared to 2001 (p < 0.001). There was no significant difference in the fluorosis rate at 12 years, with a prevalence of 32.64% in 2004 and 31.4% in 2001. For 15-year-olds, the prevalence in 2004 (16.83%) was lower than in 2001 (27.6%). No increase was observed in the prevalence or severity of fluorosis in Salvador from 2001 to 2004.

Fluorose dentária em escolares de 12 e 15 anos de idade. Salvador, Bahia, Brasil, nos anos 2001 e 2004 / Dental fluorosis in schoolchildren 12 and 15 years of age in Salvador, Bahia, Brazil, in 2001 and 2004

O objetivo deste trabalho foi comparar os resultados de dois estudos populacionais, conduzidos em Salvador, Bahia, Brasil, sobre a prevalência e severidade da fluorose dentária nas idades de 12 e 15 anos. Discutiram-se as metodologias dos estudos em relação ao processo amostral, calibração dos examinadores, sistemática de coleta, comparando-se as diferenças obtidas por meio do teste do qui-quadrado e intervalo de confiança (95 por cento), obtidas pelo índice de Dean. Foram examinados 3.313 adolescentes de 12 e 15 anos, em 2001, e 1.032, em 2004. Nos dois períodos, procedeu-se à calibração dos examinadores, e as amostras foram de base populacional. No segundo estudo, houve maior proporção de alunos de escolas públicas nas duas idades em relação ao ano de 2001 (p < 0,001). Não existiu diferença na ocorrência da fluorose aos 12 anos, com uma prevalência de 32,64 por cento, em 2004, e 31,4 por cento, em 2001. Já aos 15 anos, em 2004 observou-se uma prevalência inferior a do ano de 2001 ­ 16,83 por cento e 27,6 por cento, respectivamente. Não pode se observar, neste período, tendência de incremento da prevalência ou severidade da fluorose em Salvador.

Fluorose dentária em escolares de 12 a 15 anos de idade, Salvador-Bahia, Brazil, 2004 / Dental fluorosis in schoolchildren from 12 to 15 years-old, Salvador-BA, Brasil, 2004

Este trabalho objetivou, através de um estudo transversal com 2.110 escolares de 12 a 15 anos de idade, verificar a prevalência e severidade da fluorose dentária em Salvador-Ba, testando a diferença de prevalência entre idade e tipo de estabelecimento de ensino. Os dados foram obtidos através de umquestionário semi-estruturado e exame clínico, aplicando o índice de Dean, segundo orientação da OMS. Os resultados mostraram uma prevalência de22,47 por cento das alterações, com predomínio dos graus muitoleve e leve. Houve uma associação significativa coma idade, onde os indivíduos mais jovens apresentaram maior prevalência, sendo esta de 32,4 por cento e 16,8 por cento para as idades de 12 a 15 anos,respectivamente. Não foi encontrada associação entre a presença de fluorose e escolas públicas e privadas. Apesar de neste grupo a fluorose não parece se constituir um problema de saúde pública, vê-se a necessidade de continuada igilância da mesma.