Impact of orthodontic correction of dental crowding with pre-molar extraction in the anterior mandible evaluated by cone-beam computed tomography.

INTRODUCTION: To evaluate, by cone-beam computed tomography (CBCT), the change in thickness and height of the alveolar bone and interdental septum in the anterior mandible after orthodontic treatment for dental crowding using tooth extraction. MATERIAL AND METHODS: The sample consisted of 48 mandibular incisors from adult patients who presented with Class I malocclusion and required orthodontic treatment with the extraction of mandibular premolars. CBCT images were taken before starting the treatment (T1) and three months after treatment (T2). The following measurements were evaluated: width and height of the alveolar bone and the interdental septum, the distance between the cementoenamel junction and the bone ridges (F-CEJ-MBC and L-CEJ-MBC), as well as the vertical positioning and inclination of the incisor, using the Lingual Plane as the reference point. The paired Student's t-test and Pearson correlation were used with a significance level of 5%. RESULTS: A significant increase was observed in the distance L-CEJ-MBC, which shows the appearance of bone dehiscence. The degree of dental crowding was not a risk factor for the development of dehiscence. The decrease in the incisor inclination and intrusion was related to the formation of dehiscence on the lingual surface. CONCLUSION: The variation in the incisor's inclination and intrusion during the treatment of dental crowding using tooth extraction are related to the formation of bone dehiscence on its lingual surface.

Bone changes in the mandibular incisors after orthodontic correction of dental crowding without extraction: A cone-beam computed tomographic evaluation.

PURPOSE: This study aimed to evaluate changes of the alveolar bone and interdental bone septum of the mandibular incisors through cone-beam computed tomography (CBCT) after orthodontic treatment of mandibular dental crowding without dental extraction. MATERIALS AND METHODS: The sample consisted of 64 CBCT images (32 pre-treatment and 32 post-treatment) from 32 adult patients with class I malocclusion and an average age of 23.0±3.9 years. The width and height of the alveolar bone and interdental septum, the distance between the cementoenamel junction (CEJ) and the facial and lingual bone crests, and the inclination of the mandibular incisors were measured. RESULTS: The distance between the CEJ and the marginal bone crest on the facial side increased significantly (P<0.05). An increased distance between the CEJ and the bone crest on the facial and lingual sides showed a correlation with the irregularity index (P<0.05); however, no significant association was observed with increasing mandibular incisor inclination (P>0.05). The change in the distance between the CEJ and the marginal bone crest on the facial side was correlated significantly with bone septum height (P<0.05). CONCLUSION: Bone dehiscence developed during the treatment of crowding without extraction only on the incisors' facial side. Increasing proclination of the mandibular incisor was not correlated with bone dehiscence. The degree of dental crowding assessed through the irregularity index was associated with the risk of developing bone dehiscence. The interdental septum reflected facial marginal bone loss in the mandibular incisors.

Evaluation of Different Heights of Prosthetic Crowns Supported by an Ultra-Short Implant Using Three-Dimensional Finite Element Analysis.

PURPOSE: To apply finite element analysis (FEA) to investigate the stress distribution in a 4-mm-high ultrashort implant when supporting crowns of different heights in order to test the possibility of using this implant unitarily in the posterior edentulous mandible. MATERIALS AND METHODS: Three models of atrophic mandibles were created (M1, M2, and M3). Each model contained a 4-mm-length implant of a titanium-zirconium alloy, screw-type with internal connection, supporting nonsplinted screwed-in crowns of 10, 12.5, and 15 mm in height. Axial and oblique loads were simulated in the three model crowns. RESULTS: In an oblique load, the stress tended to be concentrated in the lingual region. In the qualitative results of the axial load, peaks of tension occurred in the lower angle between the inner groove and the inner conical portion of the implant. Regarding the differences in crown height, the 15-mm height produced a higher stress peak due to the lever effect of the crown under an oblique load. CONCLUSION: Within the limits of this study, the results suggest the possibility of using single crowns of proposed heights with unitary ultrashort implants installed in the posterior edentulous mandible, so long as there is no oblique load on the crown.

Reproducibility of cone-beam computed tomographic measurements of bone plates and the interdental septum in the anterior mandible.

PURPOSE: This study aimed to introduce a novel method to evaluate the alveolar bone and interdental septum in the anterior mandible using cone-beam computed tomography (CBCT). MATERIALS AND METHODS: Fifty-six CBCT scans from adult patients were selected. The CBCT scans were obtained before and after orthodontic treatment. The following measurements were taken: width of the alveolar bone and the interdental septum, height of the interdental septum, height of the bone plates, distance between the cementoenamel junction and marginal bone crests, and vertical positioning of the mandibular incisor, using the lingual plane as a reference. To test the reproducibility and the stability of the lingual plane, a triangle was traced in the anterior mandible. The intra-class correlation coefficient (ICC) was used to determine intra- and inter-examiner agreement. The paired Student t-test was used to evaluate the area of the triangle and the reproducibility of all measurements. RESULTS: The ICC was excellent for the alveolar bone and dental measurements (0.9989 and 0.9977, respectively), as well as for the interdental septum (0.9987 and 0.9961, respectively). The area of the triangles showed stability in the lingual plane (P>0.05). For the alveolar bone, mandibular incisor, and interdental septum measurements, no statistically significant differences were found between the 2 examiners (P>0.05), confirming the technical reliability of the measurements. CONCLUSION: The method used in this study provides a valid and reproducible assessment of alveolar bone dimensions in the anterior mandible measured on CBCT images.

Avaliação estrutural do braquete Roth Max ­ análise química, física e metalográfica / Structural assessment of roth max bracket ­ chemical, physical, and metallographic analysis

Introdução: As características ideais dos braquetes ortodônticos são alto potencial anticorrosivo, baixa concentração de níquel, boa dureza, curvatura da base adequada, paredes das canaletas lisas e ainda se constituirem em monobloco. O objetivo deste trabalho foi analisar as características químicas, físicas e metalográficas do braquete Roth Max, a fim de verificar os seus benefícios na clínica ortodôntica. Métodos: Foram utilizados dois conjuntos de braquetes ortodônticos. A análise química foi realizada através de três métodos: espectrometria, combustão e leitura por meio de infravermelho e nitrogênio total. A análise metalográfica foi realizada por meio de microscopia óptica, força atômica e magnética e ferritoscopia. A análise física foi realizada por meio de microdureza vickers. Resultados: A análise química mostrou a seguinte composição: Cr- 17%; Mn- 10.8%; Mo- 3.2%; C- 0.65%; N- 0.18%; Cu- 0.1%; Ni- 0.1%; Al- 0.1%; Co- 0.016%; Zn- 0.003%; Pb- 0.004%; Ti- 0.004%; Sn- 0.005% e V- 0.007%. Na análise metalográfica foi observada ausência de solda, presença de poros, estrutura duplex (ferrita e austenita). Na análise física, as médias das microdurezas na secção longitudinal foram de 242 HV1 (base), 213 e 212 HV1 (aletas). Na secção frontal foi de 217 HV1 (base). Conclusões: O teor de carbono excedeu o limite máximo indicado para os aços duplex. Os teores de nitrogênio e molibdênio elevaram o potencial anticorrosivo. A microdureza foi considerada eficiente para a clínica ortodôntica. A análise metalográfica não encontrou presença de solda, mas evidenciou uma grande quantidade de poros e heterogeneidade na microestrutura entre as frações volumétricas de ferrita e austenita.(AU)

Introduction: Ideal characteristics of orthodontic brackets include high anti-corrosive potential, high nickel concentration, good hardness, adequate base curvature, smooth channel walls, and their monoblock form. The present study aimed to analyze the chemical, physical and metallographic characteristics of the Roth Max bracket to verify its benefits in orthodontic clinic. Methods: Two orthodontic bracket sets were used. Chemical analysis was performed using three methods: spectrometry, combustion, and scanning through infrared and total nitrogen. Metallographic analysis was performed by optical microscopy, atomic and magnetic force and ferrite measurement. Physical analysis was conducted using vickers microhardness. Results: Chemical analysis showed the following composition: Cr- 17%, Mn- 10.8%, Mo-3.2%, C- 0.65%, N- 0.18%, Cu- 0.1%, Ni- 0.1%, Al- 0.1%, Co- 0.016%, Zn- 0.003%, Pb- 0.004%, Ti- 0.004%, Sn- 0.005%, and V- 0.007%. Metallographic analysis presented absence of welding, the presence of pores, and a duplex structure (ferrite and austenite). In the physical analysis, microhardness averages in the longitudinal section were 242 HV1 (base), and 213 and 212 HV1 (flaps). In the front section, it was 217 HV1 (base). Conclusions: The carbon content exceeded the maximum limit indicated for duplex steels. Nitrogen and Molybdenum raised the anti-corrosive potential. Microhardness was considered efficient for orthodontics clinics. Metallographic analysis found no evidence of welding, but it did find a large quantity of pores and heterogeneity in the microstructure between the ferrite and austenite volumetric fractions.(AU)

Ewing's Sarcoma: imaging findings of a patient with primary tumor in the femur and mandibular metastasis / Sarcoma de Ewing: achados imaginológicos de um paciente com tumor primário no femur e metástase mandibular

ABSTRACT Ewing's Sarcoma, a common primary bone malignancy that usually occurs in childhood and young adults, has a predilection for males and occurs mostly in the diaphysis of long bones and pelvis. This tumor rarely affects the head and neck. Histologically, this neoplasm is a small round cell tumor and there is evidence of a neuroectodermal origin. Radiographic findings of ES show an osteolytic lesion, that is not a pathognomonic feature for this neoplasm. The association of conventional imaging methods such radiography, Computed Tomograph (CT), magnetic resonance imaging (MRI), combined with scintigraphy or Positron Emission Tomography/ Computed tomography PET /CT), is essential for a correct diagnosis and treatment. Therefore, the aim of this report was to present image findings of a patient who presented with ES in the femur, and a metastasis in the mandible after eighteen months, and discuss the importance of imaging methods for a correct diagnosis, treatment and consequently, prognosis.

RESUMO O Sarcoma de Ewing é uma malignidade óssea primária comum que usualmente afeta crianças e adultos jovens. O Sarcoma de Ewing tem predileção por homens e acomete na maioria das vezes a diáfise dos ossos longos e a pelve. Raramente esse tumor afeta a região de cabeça e pescoço. Histologicamente essa neoplasia é composta por células redondas e há evidências de uma origem neuroectodérmica. Os Achados radiográficos do SE mostram uma lesão osteolítica que não é característica patognomonica. A associação dos métodos convencionais, como radiografia, tomografia computadorizada, ressonância magnética combinadas com cintilografia ou tomografia por emissão de positron são essenciais para o correto diagnóstico e tratamento. Desta forma,o objetivo desse trabalho é apresentar os achados imaginológicos de um paciente que apresentou Sarcoma de Ewing primário no femur e uma metástase mandibular após dezoito meses e discutir a importância dos métodos de imagem adequados para um correto diagnóstico, tratamento e consequentemente o prognóstico.

Enamel pearl diagnosed by cone beam computed tomography: A clinical case report.

Little research has been performed on tomographic observations of the dental development anomaly known as enamel pearl. This article presents a clinical case report in which enamel pearl was detected through cone beam computed tomography (CBCT). In this study, a patient was referred to undergo a CBCT of the left maxillary molar region, due to the patient's pain symptoms in this region. The CBCT showed the existence of an enamel pearl in tooth 27. A precise diagnosis made it possible for the patient to begin the preventive treatment against periodontal disease in tooth 27.

Accuracy of various imaging methods for detecting misfit at the tooth-restoration interface in posterior teeth.

PURPOSE: The present study aimed to evaluate which of the following imaging methods best assessed misfit at the tooth-restoration interface: (1) bitewing radiographs, both conventional and digital, performed using a photostimulable phosphor plate (PSP) and a charge-coupled device (CCD) system; (2) panoramic radiographs, both conventional and digital; and (3) cone-beam computed tomography (CBCT). MATERIALS AND METHODS: Forty healthy human molars with class I cavities were selected and divided into 4 groups according to the restoration that was applied: composite resin, composite resin with liner material to simulate misfit, dental amalgam, and dental amalgam with liner material to simulate misfit. Radiography and tomography were performed using the various imaging methods, and the resulting images were analyzed by 2 calibrated radiologists. The true presence or absence of misfit corresponding to an area of radiolucency in regions subjacent to the esthetic and metal restorations was validated with microscopy. The data were analyzed using a receiver operating characteristic (ROC) curve, and the scores were compared using the Cohen kappa coefficient. RESULTS: For bitewing images, the digital systems (CCD and PSP) showed a higher area under the ROC curve (AUROC) for the evaluation of resin restorations, while the conventional images exhibited a larger AUROC for the evaluation of amalgam restorations. Conventional and digital panoramic radiographs did not yield good results for the evaluation of resin and amalgam restorations (P<.05). CBCT images exhibited good results for resin restorations (P>.05), but showed no discriminatory ability for amalgam restorations (P<.05). CONCLUSION: Bitewing radiographs (conventional or digital) should be the method of choice when assessing dental restoration misfit.

Clinical, Imaging, and Laboratory Findings in Sjögren's Syndrome.

Sjögren's syndrome (SS) is a rare condition characterized by structural damage and secretory dysfunction of the lacrimal and salivary glands that leads to dryness, particularly xerophthalmia (eyes) and xerostomia (mouth). No cure is known; however, the effects of the disease are manageable and symptoms may be reduced. Although the salivary damage is irreversible, the dental decay and oral infections may be prevented, which highlights the importance that the clinician plays in the diagnosis and management of SS. The cardinal features of this disease are summarized through the case report of primary SS in a 23-year-old woman who received an early diagnosis based on clinical features, laboratory investigations, lower lip biopsy, and imaging findings.

Dentinogenesis imperfecta type II: A case report with 17 years of follow-up.

Dentinogenesis imperfecta is a dominant autosomal hereditary disorder of dentin formation that affects the deciduous and permanent teeth. Its etiology is characterized by inadequate cell differentiation during odontogenesis. The clinical characteristics of dentinogenesis imperfecta are discolored teeth with a translucency that varies from gray to brown or amber. Radiographically, the teeth exhibit pulp obliteration, thin and short roots, bell-shaped crowns, and periapical bone rarefaction. The aim of this report was to present a case of dentinogenesis imperfecta type II that was followed up over a 17-year period. This report also presents scanning electron microscopy images of the enamel and dentin, showing that both were altered in the affected teeth. The disease characteristics and the treatments that were administered are reported in this study to guide dentists with respect to the need for early diagnosis and adequate follow-up to avoid major sequelae.

Uso da radiografia transcraniana para detectar alterações morfológicas no côndilo mandibular / Use of transcranial radiograph to detect morphological changes in mandibular condyles

RESUMO Objetivo: o objetivo deste estudo foi avaliar a acurácia das radiografias transcranianas (TRANS) convencionais na identificação das alterações morfológicas nos côndilos mandibulares. Métodos: a amostra consistiu em 36 côndilos mandibulares, obtidos a partir de 18 crânios secos humanos, aleatoriamente selecionados, sem identificação de idade, gênero ou etnia. Três especialistas em radiologia oral examinaram as TRANS para identificar possíveis alterações nos côndilos. Um quarto examinador realizou o exame macroscópico, que foi considerado o padrão ouro do estudo. As imagens das TRANS e os exames macroscópico foram classificados como (1) côndilos com alteração ou (0) côndilos sem alteração. A análise estatística foi realizada através do teste X 2 e da curva ROC (receiver operator characteristic). O teste Kappa intra e interexaminadores foi realizado para os examinadores 1 a 3. Resultados: o teste X2 mostrou uma associação estatisticamente significativa entre as alterações no côndilo vistas nas imagens TRANS e a presença de alterações macroscópicas (p ( 0,05). A área sob a curva ROC foi de 0,83, com 96% de sensibilidade e 70% de especificidade. O valor Kappa para a concordância intraobservador foi de 0,78, enquanto que a concordância interexaminador foi de 0,71. Conclusão: o uso de radiografias transcranianas apresentou-se como método eficaz para a detecção de alterações morfológicas no côndilo mandibular.

ABSTRACT Purpose: to evaluate the accuracy of conventional transcranial radiographs (TRANS) to identify morphological changes in mandibular condyles. Methods: the sample consisted of 36 mandibular condyles, obtained from 18, randomly selected, dried human skulls, without the identification of age, gender, or ethnicity. Three experts in dental radiology examined the TRANS to identify possible changes in the condyles. The fourth examiner performed the macroscopic examination, which was considered the gold standard of the study. The condyles in both TRANS images and macroscopic examinations were classified as mandibular condyles with change (1) or no change (0). Statistical analyses were performed using the X 2 and the receiver operating characteristic (ROC) curve. Kappa intra- and interobserver tests were performed for examiners 1 to 3. Results: the X2 test showed a statistically significant association between changes in the condyle in the TRANS images and the presence of macroscopic changes in the condyle (p ( 0.05). The area under the curve was 0.83, with 96% sensitivity and 70% specificity. The weighted kappa value for intraobserver agreement was 0.78, while the interobserver agreement was 0.71. Conclusion: the use of TRANS proved to be an effective method to detect morphological changes in the mandibular condyle.

The use of digital periapical radiographs to study the prevalence of alveolar domes.

PURPOSE: In the present study, we coined the term 'alveolar dome' and aimed to demonstrate the prevalence of alveolar domes through digital periapical radiographs. MATERIALS AND METHODS: This study examined 800 digital periapical radiographs in regard to the presence of alveolar domes. The periapical radiographs were acquired by a digital system using a photostimulable phosphor (PSP) plate. The χ(2) test, with a significance level of 5%, was used to compare the prevalence of alveolar domes in the maxillary posterior teeth and, considering the same teeth, to verify the difference in the prevalence of dome-shaped phenomena between the roots. RESULTS: The prevalence of alveolar domes present in the first pre-molars was statistically lower as compared to the other maxillary posterior teeth (p<0.05). No statistically significant difference was observed in the prevalence of alveolar domes between the maxillary first and second molars. Considering the maxillary first and second molars, it was observed that the palatal root presented a lower prevalence of alveolar domes when compared to the distobuccal and mesiobuccal roots (p<0.05). CONCLUSION: The present study coined the term 'alveolar dome', referring to the anatomical projection of the root into the floor of the maxillary sinus. The maxillary first and second molars presented a greater prevalence of alveolar domes, especially in the buccal roots, followed by the third molars and second pre-molars. Although the periapical radiograph is a two-dimensional method, it can provide dentists with the auxiliary information necessary to identify alveolar domes, thus improving diagnosis, planning, and treatment.

Accuracy of Digital Versus Conventional Periapical Radiographs to Detect Misfit at the Implant-Abutment Interface.

PURPOSE: Misfit is a risk factor for rehabilitation with implants, and its detection is of fundamental importance to the success of treatment with implants. The use of appropriate radiographic imaging is key for a good prognosis. The aim of this study was to compare the efficacy of film and digital radiographs for the detection of misfit at the implant-abutment interface. MATERIALS AND METHODS: Digital and conventional (manual and automatic processing) radiography was performed in seven test specimens, each one with a different vertical misfit between the abutment and the platform of the implant. Scanning electron microscopy was used to confirm the misfit and to measure it. Five dental radiologists independently and blindly evaluated the images. Cohen's kappa with linear weighting was calculated to determine interexaminer and intraexaminer concordance. Statistical analyses were performed using the Cochran's Q test and the receiver operating characteristic curve (ROC). RESULTS: Interexaminer analysis showed that the kappa value was equal to 0.74, whereas the average kappa value in the intraexaminer evaluation was 0.90. Digital imaging showed the largest area on the ROC graph, and conventional images with manual processing showed the smallest area. The images obtained through conventional radiography with both manual and automatic processing showed statistically significant differences from the measurement of the gold standard (P < .05). CONCLUSION: Digital imaging can be used to evaluate misfit at the implant-abutment interface. Conventional systems of radiographic imaging do not provide sufficient information to evaluate misfit at the implant-abutment interface.

Formation of ghost images due to metal objects on the surface of the patient's face: A pictorial essay.

Panoramic radiographs are a relatively simple technique that is commonly used in all dental specialties. In panoramic radiographs, in addition to the formation of real images of metal objects, ghost images may also form, and these ghost images can hinder an accurate diagnosis and interfere with the accuracy of radiology reports. Dentists must understand the formation of these images in order to avoid making incorrect radiographic diagnoses. Therefore, the present study sought to present a study of the formation of panoramic radiograph ghost images caused by metal objects in the head and neck region of a dry skull, as well as to report a clinical case n order to warn dentists about ghost images and to raise awareness thereof. An understanding of the principles of the formation of ghost images in panoramic radiographs helps prevent incorrect diagnoses.

Comparison of 64-Detector-Multislice and Cone Beam Computed Tomographies in the Evaluation of Linear Measurements in the Alveolar Ridge.

This study compared the accuracy of linear measurements of the alveolar ridge in images obtained using 64-detector-multislice computed tomography (CT) and cone beam CT (CBCT). Eight sites were selected corresponding to the regions of molars, premolars, canines, and incisors in six dry human jaws. After the completion of multislice CT and CBCT, the jaws were sectioned into specific regions. Results showed there was no statistically significant difference between the measurements obtained from the CT images and those obtained from dry jaws (actual measurements) for all the evaluated sites (molars, premolars, and anterior teeth). There was also no statistically significant difference between the measurements obtained by the two CT methods.

Amelogênese imperfeita: relato de caso clínico / Amelogenesis imperfecta: clinical case report

Objetivos: ilustrar as alterações da Amelogênese Imperfeita no esmalte dentário e suas possíveis causas, com base na história clínica apresentada; determinar um diagnóstico preciso, segundo o exame clínico e radiográfico, assim como um plano de tratamento adequado para o caso. Relato de caso: paciente com 10 anos de idade apresentando alteração de cor (amarelo acastanhado) e superfície rugosa em todos os dentes, além de mordida aberta anterior. Na radiografia panorâmica, foram observadas coroas mais quadrangulares nos incisivos e cúspides de molares e pré-molares baixas, não bem-definidas, além de imagem radiolúcida nas coroas de todos os dentes permanentes, inclusive os que estão em formação, compatível com amelogênese imperfeita do tipo hipocalcificada. Considerações finais: alterações durante a amelogênese podem acarretar distúrbios no desenvolvimento do esmalte dentário, promovendo quantidade e qualidade deficiente. Clinicamente, podemos ter tanto um comprometimento estético (alteração de cor e superfícies rugosas dos dentes) como funcional (mordida aberta, alteração da dimensão vertical, etc.), além da possibilidade de sensibilidade aumentada. O diagnóstico precoce da Amelogênese Imperfeita é de suma importância para um tratamento mais conservador e com enfoque na prevenção dos efeitos dessa patologia.

Stylohyoid syndrome: surgical approach.

The best-known cervicopharyngeal pain is Eagle syndrome, in which symptomatic elongation of the stylomandibular process occurs and may be accompanied by stylohyoid ligament calcification. Among the causes of elongation of the styloid process, the following may be mentioned: history of trauma, styloid ligament calcification, and formation of bony tissue in the insertion of the styloid ligament. When there is no history of trauma or surgery, it is called the stylohyoid syndrome. In the current study, the clinical case of 34-year-old woman is reported, complaining of pain in the region of the neck, without any history of neck surgery or trauma. A panoramic radiograph and computed tomographic scan showed bilateral elongation of the styloid process. Extraoral surgical intervention was the treatment of choice. It is important to point out that dentists should be aware of this condition to contribute to a better diagnosis and therapeutic procedure.

Tomografia computadorizada no diagnóstico de perfuração radicular

Introdução: a perfuração é uma comunicação entre o canal radicular e a superfície externa do dente e, normalmente,ocorre durante o tratamento endodôntico, induzida por iatrogenia.Existem algumas condições que favorecem a ocorrência das perfurações. Pode-se citar a morfologia irregular dos canais radiculares, a dilaceração radicular, o erro durante o preparo da câmara pulpar, o desgaste excessivo das paredes dos canais radiculares e o preparo inadequado para colocação de pinos intrarradiculares. O diagnóstico definitivo desse tipo de iatrogenia é muito difícil devido à capacidade limitada da radiografia periapical, pois ela oferece imagem bidimensional e sobreposição de estruturas, principalmente se essa perfuração ocorrer no sentido vestibulolingual. Devido a isso, deve-se utilizar métodos de imagens que permitam avaliar todas as faces radiculares, como a tomografia computadorizada,a fim de diagnosticar e informar com maior precisão a localização das perfurações radiculares. Conclusão:por meio da apresentação de três casos clínicos, demonstrou-se a importância da tomografia computadorizada por feixe cônico no diagnóstico de perfurações radiculares