Clinical and laboratorial performance of rehabilitation of endodontically treated teeth: A systematic review.

OBJECTIVE: This systematic review aimed to analyze the clinical (survival rate, failure risk, or fracture) and laboratory performance (fracture mode or failure) of rehabilitations of endodontically treated teeth, with and without posts. MATERIALS AND METHODS: A systematic search was conducted in the Pubmed, Scopus, Web of Science, Embase, Cochrane Library, and OpenGrey databases up to March 2023, according to PRISMA guidelines. In vitro and clinical studies that compared the clinical and laboratory performance of endodontically treated teeth with and without intraradicular posts were included. Studies selection, data extraction, and risk of bias analysis were performed. RESULTS: Thirty-one in vitro and 7 clinical studies were included. For in vitro studies, fiberglass post (n = 24) was the most mentioned. The follow-up time of the clinical studies ranged from 1 to 17 years, with the fiber-reinforced composite post (n = 3) being the most evaluated, and only failure risk proved to be more favorable for using intraradicular posts. CONCLUSION: Rehabilitations of endodontically treated teeth with and without intraradicular retainers showed no difference in fracture resistance and failure mode, evaluated by in vitro studies. Clinical studies showed no difference in survival rate, but failure risk proved to be more favorable for the use of posts. CLINICAL SIGNIFICANCE: This analysis revealed significant variability between results, however, most laboratory and clinical studies revealed no difference with using the post. Furthermore, it is important to emphasize the need to evaluate the coronary remnant and the general characteristics of the tooth in each situation.

Association between sleep bruxism, use of antidepressants, and obstructive sleep apnea syndrome: A cross-sectional study.

BACKGROUND: Sleep bruxism (SB) is a condition regulated centrally, with a multifactorial etiology, which can occur secondary to systemic disorders and the use of certain medications. OBJECTIVE: The aim of this study was to identify associations between SB, obstructive sleep apnea, and hypopnea syndrome (OSAHS) and the use of antidepressants. MATERIAL AND METHODS: In this cross-sectional study, 240 individuals underwent full-night polysomnography for medical reasons. Anamnesis was performed to collect data about the use of antidepressants and general health conditions. Polysomnography was performed to analyse sleep data and assess respiratory-related events and apnea and hypopnea index (AHI). The polysomnographic assessment of SB was performed, from electrodes placed on masseter muscles and chin. SB was defined by the presence of more than two events of rhythmic masticatory muscles activity per hour of sleep. Statistical analyses were performed to compare the presence of SB and AHI, the severity of OSAHS, and the use of antidepressants. RESULTS: There were statistically significant differences between bruxers and non-bruxers when comparing AHI (48.28 ± 25.84; p = .001) and severity of OSAHS (p = .015). Regarding the use of antidepressants, comparative analyses did not show correlations with bruxism (p = .072). However, logistic regression suggests that the use of these medications may represent increased odds for SB development (OR =2.387; p = .005). CONCLUSION: The relationship between the use of antidepressants and SB remains inconclusive. SB is associated with OSAHS, mainly in its severe form. Therefore, identifying SB can raise the suspicion of the occurrence of other systemic disturbances.

Viability of Maxillary Single Crowns Supported by 4-mm Short Implants: A Finite Element Study.

PURPOSE: Short implants are increasingly being used in posterior regions to avoid grafting procedures and their related risks, costs, and morbidity. However, studies focusing on implants measuring less than 6 mm long remain scarce, and the literature does not yet have a definition of the limits inherent with their use. This study attempts to investigate whether extra-short 4-mm implants are capable of receiving a maxillary single crown. MATERIALS AND METHODS: This study evaluates, through the finite element method, the stress distribution generated at implant lengths of 4 mm and 10 mm caused by different crown heights (10, 12.5, and 15 mm) in the posterior maxilla region when submitted to axial (200 N) and oblique (100 N) loads. RESULTS: The 4-mm implant showed a similar level of performance as that of the 10-mm implant when submitted to the axial load. However, the oblique load proved to be highly detrimental to both implants, inducing stresses of up to three times higher than those achieved in conjunction with the axial load, especially in the surrounding bone and the abutment. CONCLUSION: The use of 4-mm short implants to support single crowns in the posterior maxilla region may be feasible in habitual conditions; however, the risk associated with significant oblique loads should be mitigated by adopting a mutually protected occlusion approach and using acrylic occlusal devices if necessary.

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.

Biomechanical development and evaluation of a new framework for all-on-four rehabilitation / Desenvolvimento e avaliação biomecânica de uma nova infraestrutura para reabilitações "all-on-four"

Abstract Introduction For complete rehabilitation of fully edentulous mandibles, the option for immediate loading determines the use of temporary prostheses that splint the installed implants. Although temporary prostheses with reinforcement provide rehabilitations with biomechanical benefits, the non-adoption of this recommendation coexists in different studies on immediate restorations. Objective This study evaluates a type of prosthesis to restore jaws by the all-on-four concept. Material and method: The mechanical behavior of prostheses with the modified framework was evaluated in vitro, under a cantilever mechanical unilateral bending test. Two representative groups were included in the all-on-four concept, with a G1 test group (n = 10) containing modified frameworks and a G2 control group (n = 10) that included full acrylic prostheses. The samples were submitted to thermal cycling with 500 cycles (5° ± 2 °C for 30 s, and 55° ± 2° for 30 s) and to the mechanical bending test on the cantilever. Result The Mann-Whitney test revealed a significant difference between G1 and G2 (p <0.001). In the descriptive evaluation, G1 averaged 830.50 N until the initial resin fracture, while the control group presented a mean of 403.58N. The maximum resistance until complete fracture was recorded in G1, with a mean of 903.03N, while in G2, a mean of 435.20N was recorded. The linear vertical component of the flexion was 0.68 mm and 0.39 mm until the initial fracture of the bar, respectively for G1 and G2. Conclusion The modified framework for the all-on-four protocol determined better mechanical performance when compared to the same full acrylic prosthesis model.

Resumo Introdução Para reabilitação de mandíbulas totalmente edêntulas, a opção por carga imediata determina a utilização de próteses provisórias que esplintem os implantes instalados. Apesar de provisórias com reforço proverem as reabilitações com benefícios biomecânicos, a não adoção desta indicação coexiste em diferentes estudos sobre restaurações imediatas. Objetivo Este estudo avaliou um tipo de prótese para reabilitar mandíbulas pelo conceito "all-on-four". Material e método: Foi avaliado, in-vitro, o comportamento mecânico de próteses com a infraestrutura modificada, sob ensaio mecânico de flexão unilateral em cantilever. Foram avaliados dois grupos representativos para o conceito "all-on-four", sendo um grupo teste G1 (n = 10) contendo próteses com infraestrutura modificada e outro controle G2 (n = 10) que incluiu próteses totalmente acrílicas. As amostras foram submetidas à ciclagem térmica com 500 ciclos (5° ± 2 °C por 30 segundos e 55° ± 2 °C pelo mesmo tempo) e submetidas ao ensaio mecânico à flexão sobre o cantilever. Resultado O teste de Mann-Whitney revelou diferença significativa entre G1 e G2 (p<0,001). Na avaliação descritiva, G1 mostrou média de 830,50 N até a fratura inicial em resina e o grupo controle apresentou média de 403,58N. A resistência máxima até a fratura completa foi de 903,03 N para G1 e para G2 de 435,20 N. O componente vertical linear de flexão foi 0,68 mm e 0,39 mm até a fratura inicial da barra, respectivamente para G1 e G2. Conclusão A infraestrutura modificada para o protocolo "all-on-four" proporcionou melhor desempenho mecânico quando comparado ao mesmo modelo de prótese totalmente acrílico.

Avaliação da resistência de união de uma cerâmica de óxido de zircônia submetida a tratamentos de superfície por abrasão / Evaluation of the bond strength of a ceramics of zirconia oxide subjected to surface treatments by abrasion

Resumo Introdução A cimentação adesiva, com cerâmicas puras, é um passo relevante no estabelecimento da longevidade de trabalhos protéticos, sendo estes os melhores materiais utilizados para a reposição de dentes perdidos, de forma a reabilitar o sorriso. O sistema cerâmico de zircônia não se beneficia do tratamento com ácidos e necessita de diferentes métodos para tratar sua superfície, visando à efetividade na união adesiva. Objetivo Avaliar os resultados de diferentes técnicas de jateamento e aplicação de agente de união desenvolvidas para metais e cerâmica de zircônia (Ceramill ZI®), por meio de ensaio de tração, em dois diferentes tratamentos de superfície. Material e método Foram preparadas 20 amostras de Ceramill Zi® (n = 20), em forma de cilindro, e unidas entre si por meio do cimento resinoso (Multilink®), formando 10 espécimes (n = 10). Formaram-se sete grupos experimentais com os mesmos 10 espécimes e estes receberam dois tratamentos de superfície diferentes: abrasão e aplicação de agentes silânicos de união. Resultado A análise estatística mostrou diferenças significativas na resistência à fratura dos espécimes silicatizados com Rocatec®. Os valores de resistência de união à tração, mensurados em MPa, dos grupos 1 a 7, foram, respectivamente: 2,27; 4,48; 8,06; 8,32; 9,15; 10,56 e 10,70. As médias entre os grupos se apresentam estatisticamente significantes, exceto entre os grupos 3 e 4 e entre 6 e 7. Conclusão Os resultados mostraram que o tratamento da superfície cerâmica baseado no método de silicatização promoveu melhor união nos ensaios com Ceramill ZI® e cimentados com Multilink®.

Abstract Introduction Adhesive cementation, with pure ceramics, is a relevant step in establishing the longevity of prosthetic works. Being these, the best materials used for the replacement of lost teeth, in order to rehabilitate the smile. The ceramic zirconia system does not benefit from the treatment and planning needs for its surface, effectively in adhesive therapy. Objective Evaluate the results of different blasting techniques and application of bonding agent for metals and ceramics (Ceramill ZI®) by means of a tensile test in two different surface treatments. Material and method Twenty samples of Ceramill Zi® (n = 20), cylindrical and joined with resin cooling (Multilink®), were prepared, forming 10 specimens (n ​​= 10). The first 10 ingredients were formed by 7 experimental groups and they received 2 surface problems: abrasion and application of silane bonding agents. Result The research resulted in fracture resistance of Rocatec® silica specimens. The values ​​of tensile strength, measured in MPa, of groups 1 to 7, were: 2.27; 4.48; 8.06; 8.32; 9.15; 10.56 and 10.70. We observe how to enter the groups are statistically significant, except between groups 3 and 4 and between 6 and 7. Conclusion The results of the ceramic surface treatment were based on no silicate method, promoting the union of results with Ceramill ZI® and cemented with Multilink®.

Association Between In-Office And At-Home Tooth Bleaching: A Single Blind Randomized Clinical Trial.

This controlled randomized clinical trial evaluated the effect of associating at-home and in-office bleaching procedures on tooth sensitivity (TS) and bleaching effectiveness. Forty patients subjected to on session of in-office bleaching with 38% peroxide hydrogen. Subsequently, the patients were randomly allocated to receive a second session of in-office bleaching or to use a tray containing 10% carbamide peroxide delivered during 7 consecutive days. The worst TS score reported during or after each bleaching procedure was recorded using a verbal rating scale and TS risk (score different from 0) was calculated. Color changes were measured 7 days after each in-office session (for patients receiving in-office procedures only) or after the end of at-home bleaching (for the combined protocol), and 6 months after the last procedure for both bleaching protocols. Color was assessed by a spectrophotometer and by color match with the Vita Classical and Bleach guide scales. Statistical analyses were carried out to assess possible differences between the protocols regarding the outcomes and to analyze the effect of time of assessment on color changes. The bleaching protocol did not affect the risk for and the maximum level of TS reported, irrespective of the time of assessment. In the color evaluation, the bleaching protocol also did not affect the ultimate tooth color. In conclusion, after one in-office bleaching session, there was no difference in bleaching effectiveness and TS between performing a second in-office session and associating it with 1-week at-home bleaching.

Successful and stable orthodontic camouflage of a mandibular asymmetry with sliding jigs.

The purpose of this paper is to present and discuss a simple and low-cost clinical approach to correct an asymmetric skeletal Class III combined to an extensive dental open bite that significantly compromised the occlusal function and smile aesthetics of an adult male patient. The patient did not accept the idealistic surgical-orthodontic treatment option, neither the use of temporary anchorage devices to facilitate the camouflage of the asymmetrical skeletal Class III/open bite. Therefore, a very simple and inexpensive biomechanical approach using sliding jigs in the mandibular arch was implemented as the compensatory treatment of the malocclusion. Although minor enhancements in facial aesthetics were obtained, the occlusal function and dental aesthetics were significantly improved. Furthermore, the patient was very satisfied with his new smile appearance. Some advantages of this treatment option included the small invasiveness and the remarkably low financial costs involved. Moreover, the final results fulfilled all realistic treatment objectives and the patient's expectations. Results remained stable 5 years post-treatment demonstrating that excellent results can be obtained when simple and low cost, but well-controlled mechanics are conducted.

Association between in-office and at-home tooth bleaching: a single blind randomized clinical trial

Abstract This controlled randomized clinical trial evaluated the effect of associating at-home and in-office bleaching procedures on tooth sensitivity (TS) and bleaching effectiveness. Forty patients subjected to on session of in-office bleaching with 38% peroxide hydrogen. Subsequently, the patients were randomly allocated to receive a second session of in-office bleaching or to use a tray containing 10% carbamide peroxide delivered during 7 consecutive days. The worst TS score reported during or after each bleaching procedure was recorded using a verbal rating scale and TS risk (score different from 0) was calculated. Color changes were measured 7 days after each in-office session (for patients receiving in-office procedures only) or after the end of at-home bleaching (for the combined protocol), and 6 months after the last procedure for both bleaching protocols. Color was assessed by a spectrophotometer and by color match with the Vita Classical and Bleach guide scales. Statistical analyses were carried out to assess possible differences between the protocols regarding the outcomes and to analyze the effect of time of assessment on color changes. The bleaching protocol did not affect the risk for and the maximum level of TS reported, irrespective of the time of assessment. In the color evaluation, the bleaching protocol also did not affect the ultimate tooth color. In conclusion, after one in-office bleaching session, there was no difference in bleaching effectiveness and TS between performing a second in-office session and associating it with 1-week at-home bleaching.

Resumo Este ensaio clínico controlado e randomizado avaliou o efeito da associação de procedimentos de clareamento caseiro e de consultório na sensibilidade dental (SD) e efetividade clareadora. Quarenta pacientes receberam uma sessão de clareamento de consultório com peróxido de hidrogênio a 38%. Em seguida, os pacientes foram aleatoriamente alocados para receberem uma segunda sessão de clareamento de consultório ou para usar uma moldeira com peróxido de carbamida a 10% por 7 dias consecutivos. O pior score de SD relatada durante ou após cada procedimento clareador foi mensurado usando uma escala verbal, e o risco a SD (escore diferente de 0) foi calculado. Mudança de cor foi mensurada 7 dias após cada sessão de clareamento de consultório (para paciente submetidos a apenas procedimentos de consultório) ou após o fim do clareamento de caseiro (para o protocolo combinado) e 6 meses após o último procedimento clareador para os dois protocolos de clareamento. A cor foi mensurada através de um espectrofotômetro e pelo uso das escalas Vita Clássica e Bleach guide. As análises estatísticas foram realizadas para verificar possíveis diferenças em relação aos desfechos e para analisar o efeito do momento da mensuração nas mudanças de cor. O protocolo clareador não afetou o risco e o nível máximo de SD relatado, independentemente do tempo de avaliação. Na avaliação de cor, o protocolo clareador também não afetou a cor final dos dentes. Como conclusão, após uma sessão de clareamento de consultório, não há diferença na efetividade clareadora e na SD em realizar uma segunda sessão de consultório ou associá-la com uma semana de clareamento caseiro.

Influence of Class II Elastics on Centric Relation and Centric Occlusion Discrepancy after Orthodontic Treatment / Influencia de los Elásticos de Clase II sobre la Discrepancia de Relación Céntrica para la Oclusión Céntrica Después del Tratamiento Ortodóncico

ABSTRACT: The objective of this study was to verify the influence of the use of Class II intermaxillary elastics on centric relation (CR) to centric occlusion (CO) occlusal discrepancy. A total of 30 patients had been at the contention stage for at least three months were divided in two groups: G1 - 15 had been submitted to intramaxillary orthodontic mechanics only, and G2 - 15 had used Class II intermaxillary elastics. Distances of horizontal and vertical overlap and the distance or coincidence of the mandibular dental midline in relation to the maxillary midline were measured in CR and CO positions. Intergroup comparisons were performed using the Mann-Whitney test. No statistically significant differences (P>0.05) were found between G1 and G2. Both in the horizontal and vertical directions, these discrepancies were smaller than or equal to 1mm in 96.66 % of the patients. In the transverse plane, there was no discrepancy in 63.33 % of the patients, and in 33.33 % these discrepancies were equal to 0.5 mm. The use of Class II elastic didn't be capable of increasing the occlusal discrepancies between CR and CO.

RESUMEN: El objetivo de este estudio fue verificar la influencia del uso de los elásticos intermaxilares Clase II en la discrepancia oclusal entre la relación céntrica (RC) y la oclusión céntrica (OC). Un total de 30 pacientes que permanecieron en la fase de contención durante al menos tres meses se dividieron en dos grupos: G1 - 15 fueron sometidos solamente a la mecánica ortodóncica intramaxilar, y G2 - 15 habían utilizado elásticos de clase II intermaxilar. Se midieron las distancias de traslapo horizontal y vertical y la distancia o coincidencia de la línea mediana dentaria mandibular con respecto a la línea mediana maxilar en las posiciones RC y OC. Las comparaciones entre grupos se realizaron mediante la prueba de Mann-Whitney. No se encontraron diferencias estadísticamente significativas (P> 0.05) entre G1 y G2. Tanto en las direcciones horizontal como vertical, estas discrepancias fueron menores o iguales a 1 mm en el 96,66 % de los pacientes. En el plano transversal, no hubo discrepancia en el 63,33 % de los pacientes, y en un 33,33 % estas discrepancias fueron iguales a 0,5 mm. El uso de la clase II elástica no logró aumentar las discrepancias entre RC y OC.

Long-term Stability of a Camouflage Retreatment of an Asymmetric Class III/Posterior Open Bite Using Sliding Jigs.

This article reports the camouflage retreatment of an adult patient presenting an asymmetric Class III malocclusion and posterior open bite. Sliding jigs (SJs) associated with intermaxillary elastics were used. The long-term stability of the excellent results suggests that the use of SJs to correct asymmetric posterior occlusions may be effective.

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.

Hipoplasia condilar de provável origem otológica / Hipoplasia condylar of probable otologic origin

RESUMO: A articulação temporomandibular é uma das mais complexas do corpo humano sendo o processo condilar responsável pela expressão do crescimento mandibular. A hipoplasia condilar é caracterizada por uma formação defeituosa do processo condilar. A otite média aguda é um processo inflamatório, desencadeada a partir de infecções das fossas nasais, cavidades paranasais e rinofaringe, propagadas por meio da tuba auditiva. No caso apresentado, a paciente apresentava assimetria facial desde o primeiro ano de vida, além de recorrentes casos de otite justamente nos estágios iniciais do fechamento da sutura temporotimpânica e do forame de Huschke o que facilitaria a disseminação dessa infecção otológica o que comprometeria o desenvolvimento do côndilo resultando na hipoplasia identificada, somente do lado direito. Assim, os profissionais que atuam na região da articulação temporomandibular e ouvido devem ter o conhecimento da existência e das implicações clínicas do forame de Huschke para um diagnóstico precoce e evitar o desenvolvimento das assimetrias faciais nos casos em que esta apresenta associação com sinais clínicos de infecção das áreas afetadas, restabelecendo função, estética e o estado psicológico do paciente.

ABSTRACT: The temporomandibular joint is one of the most complex of the human body and the condylar process is responsible for the expression of mandibular growth. The condylar hypoplasia is characterized by a defective formation of the condylar process. The acute otitis media is an inflammatory process, triggered from infections of the nasal cavity, paranasal sinuses and, nasopharynx, propagated through the Eustachian tube. In the presented case, the patient had facial asymmetry since the first year of life, and recurring cases of otitis just in the early stages of closing the temporal tympanic suture and in the foramen of Huschke, which would facilitate the dissemination of this ear infection which would undermine the development of condyle resulting in hypoplasia identified, only in the right side. Thus, professionals who work in temporomandibular joint and ear regions must have knowledge of the existence and clinical implications of the foramen of Huschke for early diagnosis and prevent the development of facial asymmetry where this association presents with clinical signs of infection of the affected areas, restoring function, aesthetic and, psychological state of the patient.

Avaliação dos níveis de pressão sonora emitidos pelo aparelho de ressonância magnética / Study about the consequences of different sound pressure levels emitted by magnetic resonance imaging equipment

RESUMO Objetivo: mensurar o nível de pressão sonora emitido pelo aparelho de ressonância magnética em funcionamento e verificar as sensações auditivas descritas pelos indivíduos submetidos a este exame após a realização do mesmo. Métodos: foi realizada a mensuração do ruído produzido, durante a aquisição das imagens, por meio de um medidor de nível de pressão sonora (decibelímetro) e a aplicação de um questionário com a finalidade de verificar as sensações auditivas apresentadas por estes indivíduos após a realização do exame. Tal procedimento foi aplicado a 60 indivíduos submetidos ao exame de ressonância magnética do crânio. Resultados: o nível de pressão sonora média apresentada durante a realização do exame foi inferior ao nível de intensidade considerado como risco para lesões auditivas. No entanto, sensações como zumbido, ansiedade, plenitude auricular e alívio após o término do exame foram citados pelos indivíduos após a execução do mesmo. Conclusão: é pertinente o uso de protetores auriculares como medida preventiva para o controle do nível de ruído que atinge a cóclea do indivíduo, minimizando desta forma os efeitos físicos e psicossociais decorrentes da exposição ao ruído.

ABSTRACT Purpose: to measure the sound pressure level emitted by the magnetic resonance imaging in operation and check the auditory sensations described by individuals submitted to this examination after it has been carried out. Methods: the measurement of the deep noise was conducted during image formation in this examination, by means of sound pressure level meter (decibel meter) and the application of a questionnaire for the purpose of checking the hearing sensations presented by those individuals after the exam has been carried out. This procedure was applied to sixty individuals submitted to a magnetic resonance imaging of the skull. Results: it was found that the average of sound pressure level presented while the examination was carried out was lower than the level of intensity considered being a risk for auditory damages. However sensations like tinnitus, anxiety, auricular plenitude and relief after the end of the examination were mentioned by the individuals after it had been carried out. Conclusion: the use of hearing protectors is relevant as a preventive measure for controlling the level of noise that affects the individual's cochlea, thus minimizing the physical and psycho-social effects resulting from noise exposure.

Morse taper internal connection implants: would abutment reseating influence retention?

Abstract Aim: To investigate whether the removal and reseating of the abutment influences the retention of Morse taper implant system. Methods: Two Morse taper implant systems were selected: Bicon Dental ImplantTM system (Bicon, LLC, Boston, MA, USA) and Kopp Implant(r) system (Kopp(r), Curitiba, PR, Brazil). In both systems, the abutment is connected to the implant with a locking taper. To seat the abutment, the same vertical force was applied in both systems. It was measured the compressive force necessary to engage effectively the locking taper connection and the tensile force to displace it. Results: The compressive force was determined by four activations in each abutment-implant set, and the sum of these forces was 21 N and 17 N in the BiconTM and Kopp(r) systems, respectively. Next, a tensile test was performed, revealing that the BiconTM system presented a 208 N resistance, whereas it was 194 N in the Kopp(r) system. Other three rounds of compression and tensile loads were applied, removing and reseating the abutment. We obtained the following tensile values: 367 N, 500 N and 756 N in the BiconTM System and 336 N, 360 N and 420 N in the Kopp(r) system. Conclusions: When the sets were subjected to repeated rounds of compressive and tensile forces, displacing and reseating the abutment, the tensile value increased.

Evaluation of Apical Contamination in Teeth with Prefabricated Posts Fixed with Different Dental Cements

To assess the sealing capacity of different dental cements regarding apical microleakage on teeth with prefabricated posts. Material and Methods:Forty-eight single-rooted teeth were selectedand, after having their coronal part removed at 10mm standard, underwent endodontic cleaning and preparation. The space for the post was prepared with # 3 Largo bur at 7 mm standard value. The study included the following groups: Group I, post prefabricated with # 1 intracanal glass fiber cemented with zinc phosphate cement (n = 12); Group II, post prefabricated with # 1 intracanal glass fiber cemented with conventional glass ionomer cement, Vidrion C (n = 12); Group III, post prefabricated with # 1 intracanal glass fiber cemented with chemical action resin cement, Multilink (n = 12). Two groups of six teeth each were also included, one as negative control group and the other as positive control. After cementing, teeth were tested through a dual-chamber experimental model, using Enterococcus Faecalis for apical contamination. Results:The control groups behaved as expected: positive control group with total contamination in 11 days and negative control group without any contaminated specimen within observation time of 60 days. Group I showed microleakage in all specimens for up to 29 days (100%)...

Group II and Group III showed microleakage in 50 and 49 specimens (83.33% and 75%) respectively along the research time of 60 days. Group 1 showed microleakage in all specimens for up to 29 days (100%). Group 2 and Group 3 showed microleakage in 50 and 49 specimens (83.33% and 75%) respectively along the research time of 60 days. The Log-Rank test showed differences between Groups 1 and 2 (p<0.05) and between Groups 1and 3 (p<0.05). However, there was no difference between Groups 2 and 3 (p> 0.05). The results showed higher delay in bacterial infiltration in Groups 2 and 3 when compared to Group 1.Conclusion:No cement completely prevented infiltration during the experimental period. Zinc phosphate cement had the lowest apical sealing capacity while glass ionomer cement and resin cement showed similar results...

Utilização da tomografia computadorizada para o diagnóstico da articulação temporomandibular / Use of CT for diagnosing temporomandibular joint

A tomografia computadorizada desempenha um papel importante no diagnóstico de anomalias e condições patológicas da ATM, permitindo a visualização completa da região articular, fornecendo um diagnóstico mais preciso. Para avaliação das imagens tomográficas é necessário que o profissional tenha o conhecimento da anatomia seccional da região articular, para que o mesmo reconheça as alterações estruturais. Assim, foi exposto e descrito neste trabalho as características tomográficas de normalidade, alterações morfológicas e condições patológicas mais encontradas na região da articulação temporomandibular. Sendo a tomografia computadorizada um exame de imagem superior aos métodos convencionais de imagem para ATM, pois permite uma visualização tridimensional adequada e apurada de todos os detalhes ósseos sem a limitação das sobreposições, fornecendo o tamanho e formato real das estruturas anatômicas, alterações morfológicas e condições patológicas.

The computed tomography plays an important role in the diagnosis of anomalies and pathological conditions of the TMJ, providing a complete visualization of joint region, providing a more accurate diagnosis. For evaluation of the images is necessary to the professional the knowledge of sectional anatomy of the joint region, so he can recognize the structural changes. Therefore, it was explained and described in this study the characteristics of normal CT, morphological and pathological conditions commonly found in the region of the temporomandibular joint. The Computed tomography is an imaging exam superior than the conventional imaging exam for TMJ, because it allows an adequate and accurate three-dimensional visualization of all details of the bone, without the limitation of overlap, providing the real size and shape of the anatomical structures, morphological changes and pathological conditions.

Tooth displacement in shortened dental arches: a three-dimensional finite element study.

STATEMENT OF PROBLEM: Some patients may opt for a prosthetic rehabilitation without replacing all missing teeth, finishing treatment with a reduced dental arch. This choice may be due to biologic reasons or financial restrictions. It is unclear if a reduced dental arch functions as well as a complete dental arch. PURPOSE: The purpose of this study was to analyze whether shortened dental arches could result in tooth displacement. MATERIAL AND METHODS: Four different 3-dimensional maxillary and mandibular arches with different levels of arch length reduction were created. In all models, anatomic structures that represent the temporomandibular joint, cortical and cancellous bone, enamel, dentin, and periodontal ligament were modeled. Mechanical properties were attributed to each anatomic component, and a total occlusal load of 100 N on masseter, temporal, and medial pterygoid muscles was simulated for each model. The MSC. Patran software was used for the preprocessing and postprocessing of the biomechanical analysis of the models. One complete dental arch was used as the control. RESULTS: The simulations showed that shortened dental arches presented greater tooth displacements than those found in a complete dental arch. The changes in mandibular tooth position were greater than those observed in the maxillary arches. In finite element models 1 and 2, the largest maxillary displacements were found for posterior teeth. CONCLUSIONS: Decreasing numbers of occlusal units resulted in increasing amounts of displacements of the remaining teeth, which may compromise dental stability in patients with shortened dental arches.

Interdisciplinary treatment of a class III patient with congenitally absent maxillary lateral incisors.

UNLABELLED: The purpose of this paper is to present a case report of an adult Class III patient presenting bilateral congenitally missing maxillary lateral incisors that compromised occlusal function as well as smile and facial esthetics. After the interdisciplinary diagnosis, spaces for prosthetic substitution were opened with the help of miniscrews. The orthodontic therapy achieved a better dental relationship, and the final interdisciplinary treatment results represented a significant improvement in function and both dental and facial esthetics. CLINICAL SIGNIFICANCE: The interdisciplinary treatment of orthodontics and restorative dentistry is very important because the two complement each other in search of the best for the patient. This case demonstrates very well that where orthodontics provided the best tooth position prior to implant placement and restorations.

Análise de tensões em prótese fixa dentoimplantossuportada com pilar intermediário / Stress analysis in tooth-implant-supported fixed prosthesis with pier abutment

Em algumas situações clínicas em que pacientes parcialmente edêntulos apresentam a indicação para prótese fixa de cinco elementos dentoimplantossuportada, o implante pode se tornar algumas vezes o pilar intermediário dessa prótese. Esse tipo de prótese deve ser feito com cautela, tendo em vista possíveis complicações biomecânicas, pelas diferenças de mobilidade entre dente e implante e pela diferença na absorção e na distribuição das cargas funcionais. O objetivo desse trabalho foi analisar, por meio do método dos elementos finitos (MEF), as tensões geradas em uma prótese fixa dentoimplantossuportada de cinco elementos, modelada pelo programa computacional Ansys Revisão 5.7, sendo composta por dois dentes como pilares terminais, dois pônticos e um implante como pilar intermediário unidos de forma rígida. Foi aplicada uma carga vertical com valor nominal de 100 Newtons (N), distribuída uniformemente nas superfícies oclusais dos dentes posteriores. Pôde-se observar em uma análise qualitativa que o maior deslocamento da prótese no sentido oclusogengival foi na região dos pônticos, com valor máximo de deslocamento de 6,4 micrometros (µm). A tensão equivalente de Von Mises SEQV foi de 77,4 Megapascal (MPa) notando uma distribuição de tensões semelhante por toda infraestrutura metálica, na região entre as coroas protéticas. Concluiu-se que a infraestrutura metálica rígida exerce papel fundamental na distribuição e absorção das tensões e no deslocamento do conjunto protético e o implante intermediário não atua como fulcro de uma alavanca Classe I.

In some clinical situations, partially edentulous patients can have indication for a five-element implant-supported prosthesis, with one of those implants being the pier abutment. This type of prosthesis should be constructed with caution, because of possible biomechanical uncertainties, due to different displacement behaviors and the distribution of the functional loads involved in the process. The aim of this work was to analyze by Finite Element Method (FEM) the global behavior of stresses and displacements involved in a tooth-implant-supported fixed prosthesis with five elements, having two teeth as terminal abutments, two bridges and an implant working as an intermediate abutment. The Ansys 5.7 program has been used as a computational tool. A nominal vertical load of 100 N has been applied, uniformly distributed, on the occlusive surfaces in the posterior teeth. It is possible to conclude, in a qualitative analysis, that the prosthesis showed a higher displacement in the occlusion-gingival direction of the bridges, with a value around 6,4 µm. The equivalent Von Misses stresses (SEQV) showed a maximum value of 77,4 MPa in the metallic bar among the prosthetic crowns. It can be concluded that the infra-structure has an important function in the distribution and absorption of stresses and displacements of the whole prosthetic set and the implant did not work as pier abutment.