Mechanical behavior of different machinable ceramic crowns using vertical and horizontal preparations: an in-vitro study / Comportamento mecânico de diferentes coroas cerâmicas usináveis usando preparos verticais e horizontais: um estudo in vitro

Objective: the aim of this study was to compare the mechanical behavior of different ceramics when used in thin vertical preparations versus traditional horizontal preparation. Material and Methods: two stainless-steel dies were milled to simulate a minimally invasive vertical preparation (VP) and a traditional horizontal preparation (HP) for an all-ceramic crown of a maxillary first premolar. The stainless-steel dies were duplicated using epoxy resin. Eighty monolithic crowns were milled and divided into 2 groups according to preparation design. Each design group was subdivided into 4 sub-groups according to material (n=10): IPS e.max CAD (lithium disilicate), Bruxzir shaded zirconia (full contour zirconia), CeraSmart (resin nanoceramic) and CEREC Tessera (advanced lithium disilicate). The crowns were cemented on their relevant epoxy resin dies using self-adhesive resin cement. All specimens were subjected to 15,000 thermocycles and then loaded to fracture in a universal testing machine. Data were analyzed using two-way ANOVA and Tukey pair wise comparison test. Results: the fracture resistance mean values of the VP (1344 + 118 N) was significantly lower than the HP design (1646 + 191 N). Ceramic crowns made of full contour zirconia had higher fracture resistance mean values (2842 + 380 N) than advanced lithium disilicate (1272 + 125 N) followed by lithium disilicate crowns (983 + 52 N) and resin nanoceramic (882 + 61 N). Conclusion: both vertical and horizontal preparations, regardless the different ceramic materials, showed clinically acceptable fracture resistance values. (AU)

Objetivo: o objetivo deste estudo foi comparar o comportamento mecânico de diferentes cerâmicas quando utilizadas em preparos verticais finos ou preparos horizontais tradicionais. Material e Métodos: dois modelos de aço inoxidável foram fresados para simular um preparo vertical minimamente invasivo (PV) e um preparo horizontal tradicional (PH) para uma coroa totalmente em cerâmica de um primeiro pré-molar superior. As matrizes de aço inoxidável foram duplicadas usando resina epóxi. Oitenta coroas monolíticas foram fresadas e divididas em 2 grupos de acordo com o desenho do preparo. Cada grupo foi subdividido em 4 subgrupos de acordo com o material (n=10): IPS e.max CAD (dissilicato de lítio), zircônia Bruxzir (zircônia de contorno total), CeraSmart (resina nanocerâmica) e CEREC Tessera (dissilicato de lítio avançado). As coroas foram cimentadas em suas respectivas matrizes de resina epóxi usando cimento resinoso autoadesivo. Todos os espécimes foram submetidos a 15.000 ciclos térmicos e então carregados até a fratura em uma máquina de teste universal. Os dados foram analisados usando ANOVA com dois fatores e teste de comparação por pares de Tukey. Resultados: os valores médios de resistência à fratura do PV (1344 + 118 N) foram significativamente menores do que PH (1646 + 191 N). As coroas de cerâmica feitas de zircônia de contorno total apresentaram maiores valores médios de resistência à fratura (2842 + 380 N) do que dissilicato de lítio avançado (1272 + 125 N), seguido por coroas de dissilicato de lítio (983 + 52 N) e resina nanocerâmica (882 + 61 N). Conclusão: preparos verticais e horizontais, independentemente dos diferentes materiais cerâmicos, apresentaram valores de resistência à fratura clinicamente aceitáveis. (AU)

Correlación entre el Diagnóstico Clínico y Radiográfico de Sujetos Adultos con Erupción Pasiva Alterada

RESUMEN: El objetivo de este estudio fue determinar la correlación entre el diagnóstico clínico y radiográfico de sujetos adultos con erupción pasiva alterada. La muestra estuvo conformada por los incisivos centrales del cuadrante I de 30 sujetos adultos. Se registraron 2 mediciones clínicas: longitud de corona clínica y distancia del margen gingival (MG) a la unión cemento esmalte (UCE); y 2 mediciones radiográficas: longitud de corona anatómica y distancia del MG-UCE. Para diagnosticar EPA, se comparó el promedio de la resta entre corona anatómica y corona clínica; con el valor hipotético ( ³ 2,5 mm según Zucchelli). La muestra estuvo conformada por: 36,7 % incisivos de sujetos de sexo masculino y 63,3 % de sexo femenino; con la edad media de 25,17 años. Clínicamente, se obtuvo la media de 8,5 mm para longitud de corona clínica y 2,267 mm para sondaje MG-UCE. Radiográficamente, se obtuvo la media de 10,767 mm para longitud de la corona radiográfica y 2,47 mm para MG-UCE. Según la Rho de Spearman, el sondaje MG-UCE (clínico) con MG-UCE (radiográfico) no muestra una correlación estadísticamente significativa (p=0,227), sin embargo, al comparar la media (2,48 mm) con el valor hipotético (³2,5 mm) según la prueba t de una muestra, se determina que no existe diferencia estadísticamente significativa (p=0,864) entre ambos resultados. La radiografía con técnica paralela de Zucchelli es una excelente alternativa para un adecuado diagnóstico diferencial de la erupción pasiva alterada; de manera simple, económica y reproducible para el beneficio de clínicos y pacientes.

ABSTRACT: The aim of the study was to determine the correlation between the clinical and radiographic diagnosis of adult subjects with altered passive eruption. The population consisted of the central incisors of quadrant I of 30 adult subjects. Two clinical measurements were recorded: length of clinical crown and distance from the gingival margin (GM) to the cementum enamel junction (CEJ); and 2 radiographic measurements: length of anatomical crown and distance from the GM-CEJ. To diagnose APE, the average of the subtraction between anatomical crown and clinical crown was compared; with the hypothetical value (³ 2.5 mm according to Zucchelli). The population were: 36.7 % incisors of male subjects and 63.3 % female; with the average age of 25.17 years. Clinically, the average was 8.5 mm for clinical crown length and 2,267 mm for GM-CEJ probing. Radiographically, the average 10.767 mm was obtained for the length of the radiographic crown and 2.47 mm for GM- CEJ. According to Spearman's Rho, the GM-CEJ (clinical) probing with GM-CEJ (radiographic) does not show a statistically significant correlation (p = 0.227), however, when comparing the average (2.48 mm) with the hypothetical value (³ 2.5 mm) according to the t-test of a sample, it is determined that there is no statistically significant difference (p = 0.864) between both results. The radiography with Zucchelli technique is an excellent alternative for an adequate differential diagnosis of altered passive eruption; in a simple, economical and reproducible way for the benefit of clinicians and patients.

Resistencia a la fractura de coronas dentales fabricadas análogamente vs tecnología cad-cam. Estudio In vitro / Fracture resistance of analogally made dental crowns vs cad-cam technology. In vitro study

Resumen Antecedentes. La resistencia a la fractura de las coronas puede tener influencia en su ocurrencia, de acuerdo con el método de fabricación usado, ya sea análogamente o por medio de tecnología Cad-Cam. Objetivo. Comparar la resistencia a la fractura de las coronas individuales realizadas por dos métodos de fabricación, bajo diseño asistido por ordenador y fabricación computarizada (CAD-CAM) e inyectadas. Método. Estudio in vitro. Tamaño de la muestra 20 coronas en dos grupos: 10 coronas bajo tecnología CAD-CAM y 10 coronas inyectadas. Fueron sometidas a cargas compresivas en una máquina de ensayos universal, con una velocidad de 1mm/min y una carga de celda de 5kN hasta obtener la fractura máxima de estas. Los datos se analizaron estadísticamente utilizando las pruebas Shapiro Wilk, Mann Whitney p=0,05. Resultados. Las coronas fabricadas por Cad-Cam obtuvieron un mínimo de 602,5 Newton y un máximo de 1093 Newton, mientras que las coronas fabricadas análogamente obtuvieron un mínimo de 525,2 Newton y un máximo de 1773 Newton en el experimento con la máquina de ensayo universal para lograr su fractura. Se obtuvo una diferencia significativa en la prueba de resistencia a la factura entre ambos métodos de fabricación (p <0,001). Conclusión. Las coronas de Disilicato de litio Prensadas obtuvieron una mayor resistencia a la fractura que las coronas fabricadas via CAD-CAM.

Abstract Background. The fracture resistance of the crowns may have an influence on their appearance, according to the method of making them, either analogously or by means of Cad-Cam technology. Objective. To compare the resistance to the fracture of the individual crowns made by two manufacturing methods, under computer-aided design and computerized manufacturing (CAD-CAM) and injected. Methods. In vitro study. Sample size 20 crowns in two groups: 10 crowns using CAD-CAM technology and 10 crowns injected. Crowns were subjected to compressive loads in a universal testing machine, with a speed of 1mm / min and a cell load of 5kN until obtaining the maximum bill for these. Data were statistically analyzed using the Shapiro Wilk tests, Mann Whitney p = 0.05. Results. Crowns manufactured by Cad-Cam obtained a minimum of 602.5 Newton and a maximum of 1093 Newton, while the crowns manufactured analogously obtained a minimum of 525.2 Newton and a maximum of 1773 Newton in the experiment with the machine Universal test to achieve their fracture. A significant difference was obtained in the invoice resistance test between both manufacturing methods (p <0.001). Conclusion. Pressed Lithium Disilicate crowns obtained higher fracture resistance than crowns under design and manufacturing by computer (CAD-CAM).

Resistencia a fractura de coronas elaboradas con disilicato de litio aplicadas en diferentes terminaciones marginales / Fracture resistance of crowns prepared with lithium disilicate applied to different marginal terminations

Resumen Evaluar la influencia del tipo de terminación marginal; filo de cuchillo (F) y chamfer (C) sobre la resistencia flexural de coronas de disilicato de litio CAD/CAM en espesores de 0,8 mm y 0,5 mm. Materiales y métodos: 40 premolares superiores sanos, en 2 grupos de acuerdo con el tipo de terminación G1=F y G2=C; 2 subgrupos referentes al espesor del material Sg1=0,8mm y Sg2 0,5 mm (5 coronas por cada subgrupo), se sometieron a fuerzas de compresión vertical (v) y horizontal (h). Se observó el tipo de fractura más frecuente; cohesivas en porcelana (cp), adhesiva en porcelana (ap), mixta pequeña (mp) y mixta larga (ml). Resultados: En preparaciones a 0,8 mm y 0,5 mm, existió diferencia significativa en relación con la mejor terminación, esta fue el C; sus valores fueron, Sg1 (h=1347,2 N / v=1402,0. F; Sg1 (h=965,6 N/ v= 794,8 N). F a 0,5 mm mostró mejor desempeño ante fuerzas horizontales. C; Sg2 (h=924,8 N /v=813,4 N) y para F; Sg2 (h=1217,0 N /v= 576,0 N). Conclusiones: Tipo de fractura más frecuente es cp y ap. Terminación chamfer y filo de cuchillo pueden ser utilizados con seguridad, pues muestran valores aceptables de resistencia flexural, al reducirse el grosor de la restauración en chamfer reduce su resistencia, el filo de cuchillo la aumenta.

Abstract Objective: To evaluate the influence of the type of shoulder margins; Knife edge (F) and Chamfer (C) on the flexural strength of CAD / CAM lithium disilicate crowns in thicknesses of 0.8 mm and 0.5 mm. Materials and Methods: 40 healthy upper premolars, in 2 groups according to the type of termination G1 = F and G2 = C; 2 subgroups referring to the material thickness Sg1 = 0.8mm and Sg2 0.5mm (5 crowns for each subgroup), were subjected to vertical (v) and horizontal (h) compression forces. The most frequent type of fracture was observed; cohesive in porcelain (cp), adhesive in porcelain (ap), mixed small (mp) and mixed long (ml). Results: In preparations with 0.8 mm and 0.5 mm thicknesses, there was a significant difference in relation to the best termination, this was C; their values were Sg1 (h = 1347.2 N / v = 1402.0.F; Sg1 (h = 965.6 N / v = 794.8 N) .F at 0.5 mm showed better performance against horizontal forces C; Sg2 (h = 924.8 N / v = 813.4 N) and for F; Sg2 (h = 1217.0 N / v = 576.0 N) Conclusions: The most frequent type of fracture is cp and ap finishing chamfer and knife edge can be used safely show acceptable values of flexural strength, by reducing the thickness of the chamfer restoration reduces its strength, the knife edge increases it.

Resistencia a la tracción diametral in vitro de cinco cementos dentales usados como cementantes de puentes y coronas en prótesis fijas / In vitro diametral tensile strength of five dental cements used as bridge and crown cement in fixed prostheses

RESUMEN Objetivo: El propósito de la investigación fue evaluar la resistencia a la tracción diametral in vitro de cinco cementos dentales: BisCem, Duolink, Ketac Cem, Meron, Allcem, cuatro adhesivos convencionales y un autoadhesivo polimerizado químicamente utilizados como cementantes de puentes y coronas en prótesis fijas. Materiales y métodos: Se prepararon 100 especímenes conformados por cementos: BisCem, Duolink, Ketac Cem, Meron, Allcem, los cuales se dividieron aleatoriamente en 5 grupos de 20 especímenes cada grupo sujetas a fotopolimerización y auto polimerización de 8mm de diámetro y 5mm de alto, con 2mm de distancia aproximadamente de la lámpara para la polimerización, se utilizó un formador de probetas de polietileno de alta densidad estandarizado, el tipo de muestreo es no probabilístico. Se sometieron a los especímenes de cada grupo a la prueba de tracción utilizando una máquina de ensayo universal (zwickiLine by Zwick/Roell), hasta lograr el fracaso del cemento, sometidas a una fuerza continua de 500 kg, con una velocidad de desplazamiento fija de 1 cm/min. Resultados: La resistencia promedio a la tracción diametral de probetas del cemento BisCem fue de 38,75 ± 11,56 MPa, del cemento Duolink fue 64,30 MPa, del cemento Meron 57,14 MPa, del cemento Ketac Cem es de 32,23 MPa, del cemento BisCem (38,753 MPa) y el cemento Ketac Cem (39,233 MPa). El cemento dental Duolink es aquel que presenta mayor resistencia a la tracción diametral de probetas en comparación a Meron (57,137 MPa) que es su similar. La tabulación y el análisis han sido sometidos a los test de Shapiro Wilk, análisis de varianza ANOVA y la prueba de Tuckey los valores de cada muestra se distribuyen normalmente existiendo diferencias significativas entre los grupos estudiados. Conclusiones: Las probetas del cemento de resina adhesiva Duolink evidenció una mayor resistencia a la tracción diametral con mejores valores significativos de resistencia a diferencia de los cementos Ketac Cem, Allcem, Meron y BisCem.

SUMMARY Objetive: The purpose of the research was to evaluate the in vitro diametral tensile strength of five dental cements: BisCem, Duolink, Ketac Cem, Meron, Allcem, four conventional adhesives and a chemically polymerized self-adhesive used as bridge cements and crowns in fixed dentures . Materials and methods : 100 specimens consisting of cements were prepared: BisCem, Duolink, Ketac Cem, Meron, Allcem, which were randomly divided into 5 groups of 20 specimens each group subject to photopolymerization and self-polymerization of 8mm in diameter and 5mm high, with an approximate distance of 2mm from the lamp for polymerization, a standardized high density polyethylene specimen was used, the type of sampling is not probabilistic. The specimens of each group were subjected to tensile testing using a universal testing machine (zwickiLine by Zwick / Roell), until the failure of the cement was achieved, subjected to a continuous force of 500 kg, with a fixed displacement speed of 1 cm / min Results: The average tensile strength of diametral tensile specimens of BisCem cement was 38.75 ± 11.56 MPa, Duolink cement was 64.30 MPa, Meron cement 57.14 MPa, Ketac Cem cement was 32.23 MPa, BisCem cement (38.753 MPa ) and Ketac Cem cement (39,233 MPa). Duolink dental cement is the one with the highest tensile strength of diametral specimens compared to Meron (57,137 MPa), which is similar. The tabulation and the analysis have been submitted to the Shapiro Wilk test, ANOVA analysis of variance and the Tuckey test. The values of each sample are normally distributed with significant differences between the studied groups. Conclusions : Duolink adhesive resin cement specimens showed a higher diametral tensile strength with better significant strength values unlike Ketac Cem, Allcem, Meron and BisCem cements.

Effect of Straumann implant on crown appearance in immediate implant restoration of maxillary anterior teeth / 南方医科大学学报

OBJECTIVE@#To investigate the effect of Straumann implant on crown appearance in the immediate implant restoration of maxillary anterior teeth.@*METHODS@#This study was conducted among 86 patients undergoing immediate implant restoration of maxillary anterior teeth between January and December, 2018. We randomized the patients into control group for treatment with immediate implant restoration and study group receiving additional Straumann implant. The effects of restoration, bone absorption at 6 months, implant length, implant diameter, root protrusion, gingival color, far and middle gingival papilla, lip side gingival height, near and middle gingival papilla, and lip side gingival curve were compared between the two groups.@*RESULTS@#The repair effect in the study group was better than that in the control group ( < 0.05). The implant length and implant diameter were significantly greater in the study group than in the control group. The root protrusion, gingival color, far and middle gingival papilla, lip side gingival height, near and middle gingival papilla, and lip side gingival curve were all better in the study group. The height of marginal bone in the study group was significantly higher than that in the control group ( < 0.05).@*CONCLUSIONS@#Straumann implant can be used in immediate implant restoration of maxillary anterior teeth to achieve a better aesthetic effect.

Arch parameters and dental discrepancy (crowding and spacing) in a sample of an Afro-Colombian population / Parámetros de arco y discrepancia dental (apiñamiento y espaciamiento) en una muestra de población Afrocolombiana

The aim of this study was to determine the differences in arch length, inter-canine distance, inter-premolar distance, intermolar distance and arch shape between dental discrepancies (crowding and spacing) in a sample of dental casts from the Afro-Colombian population of San Basilio de Palenque. An analytical, cross-sectional study was conducted on a convenience sample of 63 subjects aged 11 to 57years, of Afro-Colombian origin, with full dentition from first molar to first molar, without extensive caries or restorations, and excluding casts with defects due to loss. The differences between arch (upper and lower) variables were analyzed according to dental discrepancies. Plaster models digitalized with a TR1OS3 Mono scanner with exactitude (6.9 ± 0.9 pm) and precision (4.5 ± 0.9 pm) were analyzed with Orthonalyzer software. Statistical analyses were done on SPSS software (Version 20 for Windows) and Real Statistics. Spacing discrepancy of68.25% was found for upper arch and 66.66% for lower arch; crowding discrepancy of 19.04% for upper arch and 20.63% for lower arch, and an adequate ratio of 12.69% for both arches. No statistically significant difference (p>0.05) was found between arch parameters except for inter-premolar distance on the lower arch. The most frequent arch shape in the population was oval for both upper arch, with 76.19%, and lower arch, with 71.42%. Tooth size was larger in males than females but the difference was not statistically significant.

El objetivo de este estudio fue determinar las diferencias en longitud de arco, distancia intercanina, interpremolar, intermolar y la forma de arco entre discrepancias dentales (apiñamiento y espaciamiento), en una muestra de modelos dentales de la población afrocolombiana de San Basilio de Palenque. Se realizó un estudio analítico transversal, en una muestra por conveniencia de 63 sujetos con un rango de edad entre 11 y 57 años, de origen afrocolombiano, quienes tuvieron dentición completa de primer molar a primer molar, sin caries extensas, ni restauraciones; se excluyeron los modelos con defectos por el vaciado. Se analizaron las diferencias entre las variables de los maxilares (superior e inferior) con las discrepancias dentales. Se utilizaron modelos de yeso que fueron digitalizados con el escánerTR1OS3 Mono con una exactitud de (6.9 ± 0.9 pm) y una precisión de (4.5 ± 0.9 pm)y analizados con el software Orthonalyzer. Los análisis estadísticos se llevaron a cabo utilizando el software SPSS (Versión 20 para Windows) y Real Statistics. Se encontró una discrepancia de espaciamiento de un 68,25% para el arco superior y 66,66% en el arco inferior; y una discrepancia de apiñamiento en el arco superior de 19,04% e inferior de 20,63% y una relación adecuada de 12,69% para los dos arcos. No se encontraron diferencias estadísticamente significativas (p>0.05) en los parámetros de arco a excepción de la distancia interpremolar del arco inferior. La forma de arco más frecuente en la población fue ovalada tanto en el arco superior con un 76,19% como en el arco inferior con un 71,42%. En cuanto al tamaño dental, se presentó mayor tamaño en los hombres que en las mujeres, pero este no fue estadísticamente significativo.

CAD/CAM system influence marginal fit of different ceramic types?

Objective: This study aimed to evaluate the marginal fit of zirconia and lithium disilicate ceramic restorations processed by computer-aided design (CAD)/computer-aided manufacturing (CAM) system. Materials and Methods: Ten models were prepared from a metal die, on which scanning was carried out to obtain the virtual model for the processing of zirconia and lithium disilicate ceramics using the CAD/CAM technique. Gypsum models were fabricated and used for scanning the restorations. The infrastructures were designed using software, and CAD/CAM was used to fabricate the restorations (n = 10). The analysis of the marginal discrepancy was measured at 12 points of the margin using the original metallic die. For each crown, an arithmetic average of the discrepancy values was obtained. Results: The marginal fit of the copings of lithium disilicate was 133.10 ± 26.87 μm and zirconia was 127.34 ± 47.97 μm. There was no statistically significant difference (P = 0.7709) between the materials. Conclusion: The marginal fit is similar between lithium disilicate and zirconia ceramics milled in the CAD/CAM system used.

In vitro performance and fracture resistance of novel CAD/CAM ceramic molar crowns loaded on implants and human teeth

PURPOSE: To investigate the fatigue and fracture resistance of computer-aided design and computer-aided manufacturing (CAD/CAM) ceramic molar crowns on dental implants and human teeth. MATERIALS AND METHODS: Molar crowns (n=48; n=8/group) were fabricated of a lithium-disilicate-strengthened lithium aluminosilicate glass ceramic (N). Surfaces were polished (P) or glazed (G). Crowns were tested on human teeth (T) and implant-abutment analogues (I) simulating a chairside (C, crown bonded to abutment) or labside (L, screw channel) procedure for implant groups. Polished/glazed lithium disilicate (E) crowns (n=16) served as reference. Combined thermal cycling and mechanical loading (TC: 3000×5℃/3000×55℃; ML: 1.2×106 cycles, 50 N) with antagonistic human molars (groups T) and steatite spheres (groups I) was performed under a chewing simulator. TCML crowns were then analyzed for failures (optical microscopy, SEM) and fracture force was determined. Data were statistically analyzed (Kolmogorow-Smirnov, one-way-ANOVA, post-hoc Bonferroni, α=.05). RESULTS: All crowns survived TCML and showed small traces of wear. In human teeth groups, fracture forces of N crowns varied between 1214±293 N (NPT) and 1324±498 N (NGT), differing significantly (P≤.003) from the polished reference EPT (2044±302 N). Fracture forces in implant groups varied between 934±154 N (NGI_L) and 1782±153 N (NPI_C), providing higher values for the respective chairside crowns. Differences between polishing and glazing were not significant (P≥.066) between crowns of identical materials and abutment support. CONCLUSION: Fracture resistance was influenced by the ceramic material, and partly by the tooth or implant situation and the clinical procedure (chairside/labside). Type of surface finish (polishing/glazing) had no significant influence. Clinical survival of the new glass ceramic may be comparable to lithium disilicate.

Morfologia radicular da dentição permanente Cebus apella: morfometria e anatomia macroscópica / Root morphology of the permanent dentition Cebus apella: morphometry and gross anatomy

Introdução: as semelhanças filogenéticas entre primatas não-humanos e humanos estimulam estudos de seu sistema estomatognático, visando seu uso em pesquisas. Objetivo: assim, um estudo anatômico das características externas dos dentes permanentes do Cebus apella foi realizado, comparando-as com as características humanas, a fim de se normalizar como modelo experimental. Material e Método: dois animais adultos foram utilizados. Após a retirada do tecido orgânico, os dentes foram removidos e fotografados, sendo analisados com a lupa. Resultado: os resultados mostraram que os dentes apresentavam características semelhantes ao ser humano, mas com algumas peculiaridades, como: a presença do terceiro pré-molar; as raízes apresentam menor comprimento e volume; o terço apical dos incisivos centrais, laterais superiores e inferiores é mesiodistalmente plano; os pré-molares superiores têm duas raízes individualizadas; o primeiro e segundo molares superiores têm duas raízes e os terceiros molares superiores e inferiores têm apenas uma raiz. Conclusão: os autores concluem que o Cebus apella pode ser usado como modelo experimental em substituição aos humanos em pesquisas odontológicas.

Introduction: the phylogenetic similarities between non-human primate and human being stimulate studies of its stomatognathic system, aiming its use on researches. Objective: an anatomic study of the external features of the permanent teeth of the Cebus apella was accomplished, comparing with the human features, in order to normalize as experimental model. Material and Method: two adult animals were used. After the removal of the organic tissue, the teeth were removed and photographed, being analyzed with the loupe. Result: the results showed that the teeth presented similar features to the human being, but with some peculiarities, such as: the presence of the third premolar; the roots present smaller length and volume; the apical third of the central, lateral superiors and inferior incisors are mesiodistally flat; the superior premolars have two individualized roots; the 1st and 2nd superior molars have two roots and the 3rd superior and inferior molars have just one root. Conclusion: the authors conclude that the Cebus apella can be used as experimental model in substitution to the humans in dental researches.

Caracterización morfológica de la dentición permanente de un grupo de afrodescendientes de Istmina (Chocó, Colombia) / Morphological characterization of permanent dentition of a group of Afrodescendants at Istmina (Chocó, Colombia)

Objetivo: Caracterizar la morfología de la dentición permanente de un grupo de afrodescendientes de Istmina (Chocó, Colombia) Materiales y métodos: Estudio descriptivo transversal cuantitativo que determinó la frecuencia y variabilidad de 35 rasgos morfológicos dentales coronales (RMDC) de incisivos, caninos, premolares y molares mediante la metodología de la Arizona State University Dental Anthropology System en 100 individuos autoreconocidos como afrodescendientes (50 femeninos y 50 masculinos), con edades comprendidas entre los 5 y los 18 años. Resultados: Se identificaron frecuencias significativas de winging (99%), forma de doble pala de los incisivos centrales (86%), convexidad labial (41%), cresta msial (35%), cresta distal (entre 39% y 45%) surco vestibular (entre 95% y 98%), la cresta central (82% y 80%), surco mesolingual (79%), surco distolingual (81%), reducción del hipocono (86%), cúspide de Carabelli (33%) y cúspide 7 (64%). No se encontró dimorfismo sexual y asimetría bilateral en los RMDC estudiados. Conclusiones: La frecuencia y variabilidad de los RMDC incluidos en el dendograma, demostraron que el grupo de Istmina presentó una morfología dental típica de las poblaciones afrodescendientes que se distribuyen en el litoral pacífico colombiano, las cuales derivaron de grupos de la costa occidental africana incluidos en el complejo dental de África Sahariana. De igual forma, fue posible detectar la influencia de poblaciones mestizas e indígenas que ocupan el mismo espacio geopolítico.

Aim: Characterize the permanent dentition morphology of a group of Afrodescendants of Istmina (Chocó, Colombia) Materials y methods: This quantitative cross-sectional study determined the frequency and variability of 35 incisor, canine, premolar and molar morphological features of the Arizona State University Dental Anthropology System in 100 self-described individuals as Afrodescendants (50 Female and 50 male), aged between 5 and 18 years. Results: Significant frequencies of winging (99%), double blade of the central incisors (86%), convexity of the lips (41%), crest of the shoulder (35%), and distal crest (39% to 45%) were identified (95% to 98%), central ridge (82% and 80%), mesolingual groove (79%), distolingual groove (81%), hippocampus reduction (86%), Carabelli cusp ) And cusp 7 (64%). No sexual dimorphism and bilateral asymmetry were found in the MCDS studied. Conclusions: The frequency and variability of the MCDD included in the dendrogram showed that the Isthmian group had a typical dental morphology of the Afrodescendant populations distributed on the Colombian Pacific coast, which were derived from groups of the West African coast included in The dental complex of Saharan Africa. Likewise, it was possible to detect the influence of mestizo and indigenous populations occupying the same geopolitical space.

Avaliação da resistência à fadiga e modo de falha de coroas de dissilicato de lítio com aplicação de carga nas cristas marginais / Fatigue lifetime and failure mode of lithium disilicate crowns during load application in marginal ridges

As cerâmicas à base de dissilicato de lítio apresentam propriedades mecânicas, resistência química, biocompatibilidade, baixo índice de acúmulo de placa e resultados estéticos favoráveis. Entretanto, sua resistência à fadiga e probabilidade de sobrevida (confiabilidade) em sua forma estratificada e monolítica ainda é pouco conhecida. Este estudo tem como objetivo investigar a confiabilidade e o modo de falha das coroas estratificadas de dissilicato de lítio com e sem modificação do desenho da infraestrutura e de coroas monolíticas quando submetidas ao ensaio de fadiga por intermédio da ciclagem dinâmica em água. Trinta coroas foram divididas em 3 grupos: IEC (coroas estratificadas com infraestrutura convencional), IEM (coroas estratificadas com infraestrutura modificada) e MON (coroas monolíticas). Para os grupos IEC e IEM as infraestruturas apresentavam espessura de 0,8 mm. No entanto, no desenho modificado era adicionado uma cinta lingual de 2 mm de altura conectada a postes proximais de 3,5 mm de altura, ambos com 1,3 mm de espessura. As MON eram compostas inteiramente de dissilicato de lítio e apresentavam espessura oclusal de 1,5 mm. As coroas foram cimentadas em troqueis de resina composta e submetidas a ciclagem dinâmica em água (30-300 N). Um endentador monolítico de dissilicato de lítio aplicava carga axial sobre a crista marginal mesial até a fratura, e posteriormente na crista distal. Ao final, as coroas eram analisadas em estereomicroscópio e no microscópico eletrônica de varredura (MEV) para caracterização e classificação dos danos. As falhas encontradas nas coroas foram registradas a cada 125.000 ciclos. A distribuição Weibull a 2 parâmetros (Synthesis 9, Weibull ++; Reliasoft, Tucson, AZ, USA) foi utilizada para calculo da probabilidade de sobrevida em 1, 2 e 3 milhões de ciclos. Comparações entre os grupos também foram realizadas com o módulo de Weibull e a resistência característica (número de ciclos decorrido até a fratura)...

Lithium disilicate glass-ceramic provides desirable mechanical properties, chemical resistance, biocompatibility, diminished plaque accumulation, esthetics, and favorable esthetic results. However, the fatigue life and probability of survival (reliability) of lithium disilicate in its monolithic or layered form is still poorly understood. This study aimed to investigate the reliability and failure modes of porcelain veneered lithium disilicate crowns with and without core design modification, and of monolithic crowns when subjected to cyclic fatigue in water. Thirty lithium disilicate molars crowns were made and divided into 3 groups: IEC (bilayer crown with even thickness coping, i.e. conventional core), IEM (bilayer crowns with modified core design) and MON (monolithic crowns). For groups IEC and IEM, copings presented an even thickness of 0.8 mm and the modified design consisted of 1.3 mm thickness with a lingual margin of 2.0mm height connected to full contour proximal struts of 3.5 mm height. Monolithic crowns had an occlusal thickness of 1.5 mm. Crows were luted on composite resin abutment replicas and subjected to cyclic fatigue in water (30-300 N). A monolithic indenter of lithium disilicate was used to deliver the load on the mesial marginal ridge until failure, then the same procedure was performed in the distal ridge. For failure characterization crowns were analyzed in stereomicroscope and scanning electron microscope (SEM). Failure inspection was performed every 125,000 cycles. The 2-parameter Weibull distribution (Synthesis 9, Weibull ++; Reliasoft, Tucson, AZ, USA) was used calculate the probability of survival at 1, 2, and 3 million cycles. Comparisons between groups were also made for Weibull modulus and characteristic strength (number of cycles elapsed until failure). At both 1 and 2 million cycles, reliability was significantly lower for IEM relative to MON and IEC showed no difference between the IEM and MON. At 3 million cycles...

Avaliação da resistência à fadiga e modo de falha de coroas de dissilicato de lítio com aplicação de carga nas cristas marginais / Fatigue lifetime and failure mode of lithium disilicate crowns during load application in marginal ridges

As cerâmicas à base de dissilicato de lítio apresentam propriedades mecânicas, resistência química, biocompatibilidade, baixo índice de acúmulo de placa e resultados estéticos favoráveis. Entretanto, sua resistência à fadiga e probabilidade de sobrevida (confiabilidade) em sua forma estratificada e monolítica ainda é pouco conhecida. Este estudo tem como objetivo investigar a confiabilidade e o modo de falha das coroas estratificadas de dissilicato de lítio com e sem modificação do desenho da infraestrutura e de coroas monolíticas quando submetidas ao ensaio de fadiga por intermédio da ciclagem dinâmica em água. Trinta coroas foram divididas em 3 grupos: IEC (coroas estratificadas com infraestrutura convencional), IEM (coroas estratificadas com infraestrutura modificada) e MON (coroas monolíticas). Para os grupos IEC e IEM as infraestruturas apresentavam espessura de 0,8 mm. No entanto, no desenho modificado era adicionado uma cinta lingual de 2 mm de altura conectada a postes proximais de 3,5 mm de altura, ambos com 1,3 mm de espessura. As MON eram compostas inteiramente de dissilicato de lítio e apresentavam espessura oclusal de 1,5 mm. As coroas foram cimentadas em troqueis de resina composta e submetidas a ciclagem dinâmica em água (30-300 N). Um endentador monolítico de dissilicato de lítio aplicava carga axial sobre a crista marginal mesial até a fratura, e posteriormente na crista distal. Ao final, as coroas eram analisadas em estereomicroscópio e no microscópico eletrônica de varredura (MEV) para caracterização e classificação dos danos. As falhas encontradas nas coroas foram registradas a cada 125.000 ciclos. A distribuição Weibull a 2 parâmetros (Synthesis 9, Weibull ++; Reliasoft, Tucson, AZ, USA) foi utilizada para calculo da probabilidade de sobrevida em 1, 2 e 3 milhões de ciclos. Comparações entre os grupos também foram realizadas com o módulo de Weibull e a resistência característica (número de ciclos decorrido até a fratura). Tanto em 1...

Lithium disilicate glass-ceramic provides desirable mechanical properties, chemical resistance, biocompatibility, diminished plaque accumulation, esthetics, and favorable esthetic results. However, the fatigue life and probability of survival (reliability) of lithium disilicate in its monolithic or layered form is still poorly understood. This study aimed to investigate the reliability and failure modes of porcelain veneered lithium disilicate crowns with and without core design modification, and of monolithic crowns when subjected to cyclic fatigue in water. Thirty lithium disilicate molars crowns were made and divided into 3 groups: IEC (bilayer crown with even thickness coping, i.e. conventional core), IEM (bilayer crowns with modified core design) and MON (monolithic crowns). For groups IEC and IEM, copings presented an even thickness of 0.8 mm and the modified design consisted of 1.3 mm thickness with a lingual margin of 2.0mm height connected to full contour proximal struts of 3.5 mm height. Monolithic crowns had an occlusal thickness of 1.5 mm. Crows were luted on composite resin abutment replicas and subjected to cyclic fatigue in water (30-300 N). A monolithic indenter of lithium disilicate was used to deliver the load on the mesial marginal ridge until failure, then the same procedure was performed in the distal ridge. For failure characterization crowns were analyzed in stereomicroscope and scanning electron microscope (SEM). Failure inspection was performed every 125,000 cycles. The 2-parameter Weibull distribution (Synthesis 9, Weibull ++; Reliasoft, Tucson, AZ, USA) was used calculate the probability of survival at 1, 2, and 3 million cycles. Comparisons between groups were also made for Weibull modulus and characteristic strength (number of cycles elapsed until failure). At both 1 and 2 million cycles, reliability was significantly lower for IEM relative to MON and IEC showed no difference between the IEM and MON. At 3 million cycles, only...

Development and application of automatic dental crown remover / 医疗卫生装备

Objective To develop a dental crown remover with the strength provided constantly and adjusted freely.Methods The remover was composed of a shell, a crown hook, a conduction mechanism, a strength generating mechanism and a percussion mechanism. The spring had the explosive force formed in the crown head to destruct the cohesion of the cement.Results The remover could remove the crown, with one hand freed for the protection of abutment and mucous membrane.Conclusion The remover has simple structure and easy operation, and is worth popularizing clinically.

Evaluation of a photographic method to measure dental angulation

Objective: To analyze the reliability and reproducibility of a simplified method for analysis of dental angulation using digital photos of plaster dental casts. Methods: Digital and standardized photographs of plaster casts were performed and posteriorly imported to an angle reading graphic program in order to have measurements obtained. Such procedures were repeated to evaluate the random error and to analyze reproducibility through intraclass correlation. The sample consisted of 12 individuals (six male and six female) with full permanent dentition orthodontically untreated. The analyses were bilaterally carried out, and generated 24 measurements. Results: The random error showed variation of 0.77 to 2.55 degrees for teeth angulation. The statistical analysis revealed that the method presents excellent reproducibility (p < 0.0001) for all teeth, except for the upper premolars. In spite of that, it is still considered statistically significant (p < 0.001). Conclusion: The proposed method presents enough reliability that justifies its use in the development of scientific research as well as in clinical practice. .

Objetivo: analisar a confiabilidade e reprodutibilidade de um método simplificado para análise da angulação dentária que faz uso de fotografias digitalizadas de modelos de gesso. Métodos: foram realizadas fotografias digitalizadas e padronizadas de modelos de gesso, posteriormente transportadas para um programa gráfico de leitura de ângulos, para a obtenção das medidas. Tais procedimentos foram repetidos para avaliação do erro do método casual e para a análise da reprodutibilidade por meio da Correlação Intraclasse. A amostra constituiu-se de 12 indivíduos com dentição permanente completa e não tratados ortodonticamente, sendo seis do sexo masculino e seis do feminino. As análises foram feitas bilateralmente, gerando 24 medidas. Resultados: o erro casual mostrou uma variação de 0,77 a 2,55º para a angulação dos dentes. A análise estatística revelou que o método apresenta uma excelente reprodutibilidade (r = 0,65 - 0,91; p < 0,0001) para todos os dentes, exceto para os pré-molares superiores, mas ainda assim estatisticamente significativa (p < 0,001). Conclusão: o método proposto apresenta confiabilidade suficiente para justificar seu uso no desenvolvimento de pesquisas científicas, bem como na prática clínica. .

Método para la generación de modelos de elementos finitos de dientes / Method to generation of finite element models of teeth

El objetivo del estudio fue realizar una modelación 3D con la características morfológicas de un primer premolar superior a partir de su morfometría. Teniendo como referencia un diagrama anatómico de un primer premolar superior y sus variables morfométricas, se realizó el trazado de su contorno (software Catya) considerando al menos tres cortes transversales de la figura: vista oclusal, mesio-distal (AP) y uno vestíbulo-palatino (L). El modelo 2d obtenido se completó mediante extrapolación para obtener una imagen tridimensional en malla que, posteriormente, se transforma a elementos triangulares, quedando el modelo de premolar listo para ser importado al software de análisis de elementos finitos (Ansys). Aquí, estos elementos son transformados a su vez en elementos placa, unidos por haces, lo que le confiere un comportamiento lineal e isométrico. A éstos, se ingresan los valores de las propiedades mecánicas correspondiente a cada tejido para proceder al análisis. La figura así obtenida, permite reproducir la morfología del premolar y las relaciones entre sus componentes. Además, la linealidad e isometría conferida permite estudiar el comportamiento mecánico en cualquier sección del modelo. El diseño computacional de estructuras anatómicas, a partir de un dibujo de contorno en base a su morfología y morfometría con la técnica descrita, resulta un alternativa complementaria para estudiar la morfología y realizar análisis mecánicos de dientes u otras estructuras anatómicas.

The aim of this study was making a 3D modeling with the morphological characteristics of a first premolar from its morphometry. With reference to an anatomical diagram of a first upper premolar and morphometric relationships, it performs its contour plot (software Catya) considering at least three cross-sections of the figure seen occlusal, mesial-distal (AP) and one vestibulo-palatal (L). 2d obtained model is completed by extrapolation to obtain a three-dimensional mesh which subsequently transforms triangular elements premolar model being ready to be imported into the software of the finite element analysis (Ansys) where these elements are transformed into the once plate elements connected by beams which gives a linear and isometric to which also inputs values ??of mechanical properties for each tissue for the analysis. Thus the figure obtained allows us to reproduce the morphology of the premolar and the relationships among its components, including linearity and isometry conferred allows us to study the mechanical behavior in any section of the model. Computational design of anatomical structures from a contour drawing based on their morphology and morphometry using the technique described results in a complementary alternative to study the morphology and mechanical analyzes of teeth or other anatomical structures.

Effect of the shades of background substructures on the overall color of zirconia-based all-ceramic crowns

PURPOSE: The objective of this study was to determine the effect of the color of a background substructure on the overall color of a zirconia-based all-ceramic crown. MATERIALS AND METHODS: Twenty one posterior zirconia crowns were made for twenty subjects. Seven premolar crowns and six molar crowns were cemented onto abutments with metal post and core in the first and second group. In the third group, eight molar crowns were cemented onto abutments with a prefabricated post and composite core build-up. The color measurements of all-ceramic crowns were made before try-in, before and after cementation. A repeated measure ANOVA was used for a statistical analysis of a color change of all-ceramic crowns at alpha=.05. Twenty four zirconia specimens, with different core thicknesses (0.4-1 mm) were also prepared to obtain the contrast ratio of zirconia materials after veneering. RESULTS: L*, a*, and b* values of all-ceramic crowns cemented either on a metal cast post and core or on a prefabricated post did not show significant changes (P>.05). However, the slight color changes of zirconia crowns were detected and represented by DeltaE*ab values, ranging from 1.2 to 3.1. The contrast ratios of zirconia specimens were 0.92-0.95 after veneering. CONCLUSION: No significant differences were observed between the L*, a*, and b* values of zirconia crowns cemented either on a metal cast post and core or a prefabricated post and composite core. However, the color of a background substructure could affect the overall color of posterior zirconia restorations with clinically recommended core thickness according to DeltaE*ab values.

Factors related to Bolton’s anterior ratio in Brazilians with natural normal occlusion

Aim: To verify whether some factors could be related to Bolton’s anterior ratio: buccolingual thickness of upper incisors, mesiodistal tipping of upper incisors, overjet and overbite, and if there is gender dimorphism. Methods: Thirty-five pairs of dental casts with natural normal occlusion were evaluated, proceeding from 27 females and 8 male Caucasian individuals, aged between 13 years old and 17 years and 4 months (mean age: 15y8m). A digital caliper and a ruler were used to make the measurements. Results: The anterior ratio was 77.48% ± 2.22, being statistically similar to Bolton’s, 77.20% ± 1.65. Based on Pearson’s correlation test, only the overbite presented relation to the anterior ratio. It was not found gender dimorphism. Conclusions: Overbite was inversely proportional to Bolton’s anterior ratio, hence, when the anterior ratio is increased, the overbite could be decreased and vice-versa.

Antropología dental y periodoncia: relación entre los rasgos morfológicos dentales y la enfermedad periodontal / Anthropology dental and periodontics: relationship between dental morphological traits and periodontal disease

En esta revisión de la literatura se evidencia la relación entre la antropología dental y una de las especialidades de la odontología como lo es la periodoncia, en donde la primera contribuye con base a la evidencia científica al diagnóstico y tratamiento clínico de las enfermedades periodontales cuya etiología implique un rasgo morfológico dental coronal y/o radicular

This review demonstrate the relation between dental anthropology and periodontology. Dental anthropology contribute with the diagnosis and clinical treatment of the periodontal diseases whose aetiology implies a non-metric dental traits at crown or root

Crown removal and endodontic drainage as a last method in active gingival bleeding with liver cirrhosis and periodontitis: a case report

The most common local cause of active gingival bleeding is the vessel engorgement and erosion by severe inflammation. Abnormal gingival bleeding is also associated with the systemic disturbances. Hemorrhagic disorders in which abnormal gingival bleeding is encountered include the following: vascular abnormalities (vitamin C deficiency or allergy), platelet disorders, hypoprothrombinemia (vitamin K deficiency resulting from liver disease), and other coagulation defects (hemophilia, leukemia). There are many conventional methods for gingival bleeding control, such as, direct pressure, electrocoagulation, direct suture, drainage, application of hemostatic agents and crushing and packing. If the active continuous gingival bleeding is not stopped in spite of the application of all conventional bleeding control methods, the life of patient is threatened owing to upper airway obstruction, syncope, vomiting and hypovolemic shock. Therefore, the rapid and correct hemostatic method is very important in the emergency dental care.