998 resultados para Dentition (tooth development)


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OBJETIVO: avaliar a influência da condição socioeconômica na prevalência de má oclusão na dentição decídua em uma população amazônica. MÉTODOS: esse estudo transversal compreendeu 652 crianças, de ambos os sexos, entre 3 e 6 anos de idade. Os indivíduos estavam matriculados na pré-escola na rede privada de ensino (alto nível socioeconômico; n = 312) ou, rede pública (baixo nível socioeconômico; n = 340), em Belém, no Pará. O teste chi-quadrado e estatística binominal foram usados para avaliar as diferenças entre os grupos socioeconômicos, com nível de significância considerado em p < 0,05. RESULTADOS: foi observada uma alta prevalência de má oclusão (81,44%) na amostra examinada. As meninas das escolas públicas exibiram uma prevalência significativamente menor (72,1%) em comparação às das escolas privadas (84,7%), principalmente com relação à prevalência da má oclusão de Classe II (p < 0,0001), mordida cruzada posterior (p = 0,006), sobremordida (p = 0,005) e sobressaliência (p < 0,0001). De maneira geral, a prevalência de má oclusão foi similar entre as crianças do sexo masculino dos dois grupos (p = 0,36). A perda precoce de dente decíduo foi significativamente mais prevalente no grupo com menor nível socioeconômico (20,9%) quando comparada à de crianças nas escolas privadas (0.9%), em ambos os sexos (p < 0,0001). CONCLUSÃO: a condição socioeconômica influencia a ocorrência de má oclusão na dentição decídua. Na maior metrópole da Amazônia, uma em cada cinco crianças do grupo com baixo nível socioeconômico perdeu, no mínimo, um dente decíduo antes dos sete anos.

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OBJECTIVE: To determine the prevalence of mesiodens in deciduous and mixed dentitions and its association with other dental anomalies. MATERIAL AND METHODS: Panoramic radiographs of 1,995 orthodontic patients were analyzed retrospectively, obtaining a final sample of 30 patients with mesiodens. The following aspects were analyzed: gender ; number of mesiodens; proportion between erupted and non-erupted mesiodens; initial position of the supernumerary tooth; related complications; treatment plan accomplished; and associated dental anomalies. The frequency of dental anomalies in the sample was compared to reference values for the general population using the chi-square test (c²), with a significance level set at 5%. RESULTS: The prevalence of mesiodens was 1.5% more common among males (1.5:1). Most of the mesiodens were non-erupted (75%) and in a vertical position, facing the oral cavity. Extraction of the mesiodens was the most common treatment. The main complications associated with mesiodens were: delayed eruption of permanent incisors (34.28%) and midline diastema (28.57%). From all the dental anomalies analyzed, only the prevalence of maxillary lateral incisor agenesis was higher in comparison to the general population. CONCLUSION: There was a low prevalence of mesiodens (1.5%) in deciduous and mixed dentition and the condition was not associated with other dental anomalies, except for the maxillary lateral incisor agenesis.

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The primary teeth are essential for bone development and establishment of the arches on occlusion. Thus, the congenitally absence of teeth may trigger a shift in the balance of the occlusion, promoting disharmony in the structures of the maxilla-mandibular system. However, some interventions are possible to be performed in these cases even in pediatric patients, to redirect growth, preventing growth deviations and reestablishing the aesthetic. The aim of this paper is to report the treatment of a 4-year-old child presenting congenitally absence of mandibular central and lateral incisors and maxilla lateral incisors, which consequently compromises aesthetics, occlusal function, and the development and the functional growth of the bones. The oral rehabilitation was performed with an adhesive partial denture, which was able to restore the aesthetic and the occlusal function, therefore being a viable alternative in the treatment of this patient of little age.

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Aim: To evaluate the dental development of Brazilian children and adolescents with cleft lip and palate. Methods: The sample consisted of 107 panoramic radiographs of children and adolescents with cleft lip and/or palate (cleft group) and 107 panoramic radiographs of children and adolescents without cleft lip and/or palate (control group), with chronological ages ranging from 6 to 15 years, matched in gender and chronological age within 60 days. Radiographs were digitized and masked and dental age was assessed using the method described by Demirjian et al. (1973). Three trained examiners conducted the assessments. Each examiner evaluated the radiographs three times. Data were statistically analyzed using non-parametric tests and univariate linear regression (p<0.05). Results: The dental age was overestimated in relation to the chronological age in both groups (p<0.0001). Compared to the control group, there was a delay in the dental age in the cleft group of 0.17 years (2.1 months). However, no statistically significant difference in the dental age between the cleft and the control group was found even when considering the different cleft types (p=0.152). Conclusions: There was no statistically significant difference in the dental age between the cleft and the control groups. The evaluation of dental development in individuals with cleft lip and palate should be approached in the same way as in individuals without clefts, with a focus on the individualization of diagnosis and treatment planning.

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The report is about a case of total intrusion of a deciduous central incisor involving a male patient of 14 months of age. Repositioning of the intruded tooth was performed 20 minutes after the trauma, followed by placement with sutures. Clinical and radiographic monitoring performed after 1, 2, 4, 9, and 13 months showed normal characteristics. We emphasize the development of preventive programs promoting parental awareness of the importance of looking for prompt care, resulting in a better prognosis.

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The aim of this study was to evaluate the putative influence of diabetes without metabolic control in the loss of tooth structure as well as histological changes in dentin and pulp tissue in rats. Diabetes was induced in Wistar rats (n=25) by intravenous administration of alloxan (42mg/kg). Diabetic and non-diabetic control rats were evaluated at 1, 3, 6, 9 and 12 months of follow-up. In order to evaluate the presence and progression of dental caries and periapical lesions, hemimandibles were removed and submitted to radiographical, histological, and morphometrical procedures. Dental caries were detected after radiographical and histological evaluations in diabetic group from the third month of diabetes onset, increasing gradually in frequency and severity in periods. Diabetic rats dental pulps also presented significant reduction in volume density of collagen fibers and fibroblasts at third month, parallel with a trend towards the increase in inflammatory cells volume density. Diabetic rats presented a generalized pulp tissue necrosis after 6 months of diabetes induction. Moreover, periapical lesions were not detected in control group, while these lesions were observed in all rats after 3, 6, 9, and 12 months of diabetes induction. Uncontrolled diabetes seems to trigger the loss of tooth structure, associated to histological dental changes and mediates its evolution to progressive severe pulp and periapical lesions in rats. Therefore, diabetes may be considered a very important risk factor regarding alterations in dental pulp, development of dental caries, and periapical lesions.

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During tooth eruption, structural and functional changes must occur in the lamina propria to establish the eruptive pathway. In this study, we evaluate the structural changes that occur during lamina propria degradation and focus these efforts on apoptosis and microvascular density. Fragments of maxilla containing the first molars from 9-, 11-, 13- and 16-day-old rats were fixed, decalcified and embedded in paraffin. The immunohistochemical detection of vascular endothelial growth factor (VEGF), caspase-3 and MAC387 (macrophage marker), and the TUNEL method were applied to the histological molar sections. The numerical density of TUNEL-positive cells and VEGF-positive blood vessel profiles were also obtained. Data were statistically evaluated using a one-way anova with the post-hoc Kruskal-Wallis or Tukey test and a significance level of P ≤ 0.05. Fragments of maxilla were embedded in Araldite for analysis under transmission electron microscopy (TEM). TUNEL-positive structures, fibroblasts with strongly basophilic nuclei and macrophages were observed in the lamina propria at all ages. Using TEM, we identified processes of fibroblasts or macrophages surrounding partially apoptotic cells. We found a high number of apoptotic cells in 11-, 13- and 16-day-old rats. We observed VEGF-positive blood vessel profiles at all ages, but a significant decrease in the numerical density was found in 13- and 16-day-old rats compared with 9-day-old rats. Therefore, the establishment of the eruptive pathway during the mucosal penetration stage depends on cell death by apoptosis, the phagocytic activity of fibroblasts and macrophages, and a decrease in the microvasculature due to vascular cell death. These data point to the importance of vascular rearrangement and vascular neoformation during tooth eruption and the development of oral mucosa.

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Introductions: A supernumerary tooth is one that is additional to the normal series and can be found in almost any region of the dental arch. Its etiology is not fully understood. With regard to its prevalence, it occurs more commonly in permanent dentition and twice as often in men than in women. Supernumerary teeth are classified according to their morphology and location. Their presence can cause problems such as failure of eruption, displacement of teeth, crowding and odontogenic cysts and tumors. The diagnosis is usually by routine radiographs, for the majority of such teeth are impacted and asymptomatic. Objective and Case report: The purpose of this study was to make a brief review of the relevant literature and report one clinical case of the female patient, 23 years, melanoderma, featuring three quarters molars. Final considerations: The early diagnosis proved to be important for the resolution of the case in order to minimize or even prevent the development of complications and thus establish a proper plan of treatment.

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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The aim of this article is to present the pediatric dentistry and orthodontic treatment protocol of rehabilitation of cleft lip and palate patients performed at the Hospital for Rehabilitation of Craniofacial Anomalies - University of So Paulo (HRAC-USP). Pediatric dentistry provides oral health information and should be able to follow the child with cleft lip and palate since the first months of life until establishment of the mixed dentition, craniofacial growth and dentition development. Orthodontic intervention starts in the mixed dentition, at 8-9 years of age, for preparing the maxillary arch for secondary bone graft procedure (SBGP). At this stage, rapid maxillary expansion is performed and a fixed palatal retainer is delivered before SBGP. When the permanent dentition is completed, comprehensive orthodontic treatment is initiated aiming tooth alignment and space closure. Maxillary permanent canines are commonly moved mesially in order to substitute absent maxillary lateral incisors. Patients with complete cleft lip and palate and poor midface growth will require orthognatic surgery for reaching adequate anteroposterior interarch relationship and good facial esthetics.

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Objectives: To verify the thickness and level of alveolar bone around the teeth adjacent to the cleft by means of cone beam computed tomography (CBCT) in patients with complete bilateral cleft lip and palate prior to bone graft surgery and orthodontic intervention. Method: The sample comprised 10 patients with complete bilateral cleft lip and palate (five boys and five girls) in the mixed dentition. The mean age was 9.5 years, and all subjects showed a G3 interarch relationship according to the Bauru index. The thickness of alveolar bone surrounding the maxillary incisors and the maxillary canines was measured in CBCT axial section using the software iCAT Xoran System. The distance between the alveolar bone crest and the cement-enamel junction (CEJ) was measured in cross sections. Results: The tomography images showed a thin alveolar bone plate around teeth adjacent to clefts. No bone dehiscence was observed in teeth adjacent to clefts during the mixed dentition. A slight increase in the distance between the alveolar bone crest and the CEJ was observed in the mesial and lingual aspects of canines adjacent to cleft. Conclusion: In patients with BCLP in the mixed dentition, teeth adjacent to the alveolar cleft are covered by a thin alveolar bone plate. However, the level of alveolar bone crest around these teeth seems to be normal, and no bone dehiscence was identified at this age.

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Direct composite resin restorations have become a viable alternative for patients that require anterior restorative procedures to be integrated to the other teeth that compose the smile, especially for presenting satisfactory esthetic results and minimum wear of the dental structure. Technological evolution along with a better understanding of the behavior of dental tissues to light incidence has allowed the development of new composite resins with better mechanical and optical properties, making possible a more artistic approach for anterior restorations. The combination of the increasing demand of patients for esthetics and the capacity to preserve the dental structure resulted in the development of different incremental techniques for restoring fractured anterior teeth in a natural way. In order to achieve esthetic excellence, dentists should understand and apply artistic and scientific principles when choosing color of restorative materials, as well as during the insertion of the composite resin. The discussion of these strategies will be divided into two papers. In this paper, the criteria for color and material selection to obtain a natural reproduction of the lost dental structures and an imperceptible restoration will be addressed.

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Background: Initially described by Gorlin et al. in 1962, the calcifying cystic odontogenic tumor (CCOT) may be associated with unerupted teeth, ameloblastomas, adenomatoid odontogenic tumors, and, in many cases, with odontomas. It is rare in patients in the first decade of life, particularly involving deciduous teeth. Surgery is the treatment of choice, with low recurrence rates. Case report: We present a clinical case of CCOT associated with odontoma and a missing deciduous tooth in a 3-year-old female patient. The lesion was removed under general anesthesia. The patient has been followed up for 1 year, and no recurrence was found. This appears to be the first report in such a young age

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In the present study, pterosaur skull constructions were analysed using a combined approach of finite element analysis (FEA), static investigations as well as applying classical beam theory and lever mechanics. The study concentrates on the operating regime „bite“, where loads are distributed via the dentition or a keratinous rhamphotheca into the skull during jaw occlusion. As a first step, pterosaur tooth constructions were analysed. The different morphologies of the tooth construction determine specific operational ranges, in which the teeth perform best (= greatest resistance against failure). The incomplete enamel-covering of the pterosaur tooth constructions thereby leads to a reduction of strain and stress and to a greater lateral elasticity than for a complete enamel cover. This permits the development of high and lateral compressed tooth constructions. Further stress-absorption occurs in the periodontal membrane, although its mechanical properties can not be clarified unambiguously. A three-dimensionally preserved skull of Anhanguera was chosen as a case-study for the investigation of the skull constructions. CT-scans were made to get information about the internal architecture, supplemented by thin-sections of a rostrum of a second Anhanguera specimen. These showed that the rostrum can be approximated as a double-walled triangular tube with a large central vacuity and an average wall-thickness of the bony layers of about 1 mm. On base of the CT-scans, a stereolithography of the skull of Anhanguera was made on which the jaw adductor and abductor muscles were modelled, permitting to determine muscular forces. The values were used for the lever mechanics, cantilever and space frame analysis. These studies and the FEA show, that the jaw reaction forces are critical for the stability of the skull construction. The large jugal area ventral to the orbita and the inclined occipital region act as buttresses against these loads. In contrast to the orbitotemporal region which is subject to varying loading conditions, the pattern in the rostrum is less complex. Here, mainly bending in dorsal direction and torsion occur. The hollow rostrum leads to a reduction of weight of the skull and to a high bending and torsional resistance. Similar to the Anhanguera skull construction, the skulls of those pterosaur taxa were analysed, from which enough skull material is know to permit a reliable reconstruction. Furthermore, FEA were made from five selected taxa. The comparison of the biomechanical behaviour of the different skull constructions results in major transformational processes: elongation of rostra, inclination of the occipital region, variation of tooth morphology, reduction of the dentition and replacement of teeth by a keratinous hook or rhamphotheca, fusion of naris and antorbital fenestra, and the development of bony and soft-tissue crests. These processes are discussed for their biomechanical effects during bite. Certain optional operational ranges for feeding are assigned to the different skull constructions and previous hypotheses (e.g. skimming) are verified. Using the principle of economisation, these processes help to establish irreversible transformations and to define possible evolutionary pathways. The resulting constructional levels and the structural variations within these levels are interpreted in light of a greater feeding efficiency and reduction of bony mass combined with an increased stability against the various loads. The biomechanical conclusive pathways are used for comparison and verification of recent hypothesis of the phylogenetic systematics of pterosaurs.