Microcirculation changes in gingival tissue after ultrasonic tooth preparation in beagle dogs

Abstract Ultrasonic wave technology is widely used during dental treatments. We previously demonstrated that this method protects the gingival tissue. However, the physiological change on the gingival microvasculature caused by this method remains unclear. Objective The aim of this study was to investigate the relationship between the morphological and physiological effects on gingival microcirculation when preparing teeth, using the conventional dental turbine or ultrasonic method. Methodology The lower premolar teeth of beagle dogs were prepared along the gingival margin by using a dental turbine or ultrasonic wave instrument. Gingival vasculature changes were investigated using scanning electron microscopy for corrosion resin casts. Gingival blood flow at the preparation site was determined simultaneously by laser Doppler flowmetry. These assessments were performed immediately (Day 0), at 7 days and 30 days after tooth preparation. Results At day 0, in the turbine group, blood vessels were destroyed and some resin leaked. Furthermore, gingival blood flow at the site was significantly increased. In contrast, the ultrasonic group demonstrated nearly normal vasculature and gingival blood flow similar to the non-prepared group for 30 days after preparation. No significant alterations occurred in gingival circulation 30 days after either preparation; however, the turbine group revealed obvious morphological changes. Conclusions Based on multiple approach analyses, this study demonstrated that ultrasonic waves are useful for microvascular protection in tooth preparation. Compared with a dental turbine, ultrasonic wave instruments caused minimal damage to gingival microcirculation. Tooth preparation using ultrasonic wave instruments could be valuable for protecting periodontal tissue.

Accurate extraction of outermost biological characteristic curves in tooth preparations with fuzzy regions.

BACKGROUND: The accuracy of extraction of biological characteristic curves in tooth preparations directly determines whether the tooth restorations and preparations are closely matched to allow appropriate adhesion. Ultimately, these will affect the success of the dental restoration surgery. In the process to obtain the tooth preparation, the dentist is required to grind the tooth manually and fuzzy regions may thus exist. Multiple feature curves with locally increased curvatures exist in these fuzzy regions, but only the outermost is preferred. The characteristic curve consists of points, some with and some without extreme curvature values. This study aims to extract an accurate biological characteristic curve. METHOD: This challenging problem is mapped to the search of the minimum cost path for a graph, and is solved using the well-known A* algorithm. To identify the mapped graph, the outward direction coefficient is first introduced followed by the extremality coefficient node. Both of these coefficients ensure that the biological characteristic curve can be accurately extracted. RESULTS: The conducted experiment demonstrated that the proposed algorithm can rapidly, accurately, and automatically obtain the outermost feature curve which passes through the fuzzy region of the tooth preparation. Additionally, the part of the biological characteristic curve related to the non-fuzzy region can also be accurately extracted. CONCLUSIONS: The proposed algorithm significantly improves the accuracy of the extraction curve and the quality of the restoration design.

Dentin pretreatment and adhesive temperature as affecting factors on bond strength of a universal adhesive system

Abstract Objectives: To evaluate the effects of dentin pretreatment and temperature on the bond strength of a universal adhesive system to dentin. Material and Methods: Ninety-six extracted non-carious human third molars were randomly divided into 12 groups (n=8) according to Scotchbond Universal Adhesive (SbU) applied in self-etch (SE) and etch-and-rinse (ER) mode, adhesive temperature (20°C or 37°C) and sodium bicarbonate or aluminum oxide air abrasion. After composite build up, bonded sticks with cross-sectional area of 1 mm2 were obtained to evaluate the microtensile bond strength (μTBS). The specimens were tested at a crosshead speed of 0.5 mm/min on a testing machine until failure. Fractured specimens were analyzed under stereomicroscope to determine the failure patterns in adhesive, cohesive (dentin or resin) and mixed fractures. The microtensile bond strength data was analyzed using two-way ANOVA and Tukey's test (α=5%). Results: Interaction between treatment and temperature was statistically significant for SbU applied in self-etch technique. Both dentin treatments showed higher bond strength for ER mode, regardless of adhesive temperature. When compared to control group, sodium bicarbonate increased bond strength of SbU in SE technique. Adhesive temperature did not significantly affect the μTBS of tested groups. Predominantly, adhesive failure was observed for all groups. Conclusions: Dentin surface treatment with sodium bicarbonate air abrasion improves bond strength of SbU, irrespective of adhesive application mode, which makes this approach an alternative to increase adhesive performance of Scotchbond Universal Adhesive to dentin.

An automatic robotic system for three-dimensional tooth crown preparation using a picosecond laser.

BACKGROUND: Laser techniques have been introduced into dentistry to overcome the drawbacks of traditional treatment methods. The existing methods in dental clinical operations for tooth crown preparation have several drawbacks which affect the long-term success of the dental treatment. OBJECTIVE: To develop an improved robotic system to manipulate the laser beam to achieve safe and accurate three-dimensional (3D) tooth ablation, and thus to realize automatic tooth crown preparation in clinical operations. METHOD: We present an automatic laser ablation system for tooth crown preparation in dental restorative operations. The system, combining robotics and laser technology, is developed to control the laser focus in three-dimensional motion aiming for high speed and accuracy crown preparation. The system consists of an end-effector, a real-time monitor and a tooth fixture. A layer-by-layer ablation method is developed to control the laser focus during the crown preparation. Experiments are carried out with picosecond laser on wax resin and teeth. RESULTS: The accuracy of the system is satisfying, achieving the average linear errors of 0.06 mm for wax resin and 0.05 mm for dentin. The angle errors are 4.33° for wax resin and 0.5° for dentin. The depth errors for wax resin and dentin are both within 0.1 mm. The ablation time is 1.5 hours for wax resin and 3.5 hours for dentin. CONCLUSIONS: The ablation experimental results show that the movement range and the resolution of the robotic system can meet the requirements of typical dental operations for tooth crown preparation. Also, the errors of tooth shape and preparation angle are able to satisfy the requirements of clinical crown preparation. Although the experimental results illustrate the potential of using picosecond lasers for 3D tooth crown preparation, many research issues still need to be studied before the system can be applied to clinical operations.

Dental pulp dendritic cells migrate to regional lymph nodes.

Dendritic cell (DC) migration to regional lymph nodes (RLNs) is an essential step in adaptive immunity, and cell-surface antigens on migrating DCs greatly affect the quality and quantity of subsequent immune responses. Although MHC class II(+) DC-like cells exist in the dental pulp, the lineage and function of these cells remain unknown. Here, we identified migratory DCs from the dental pulp after cusp trimming and acid etching in KikGR mice, in which the photoconvertible fluorescent protein changed from green to red upon violet light exposure. Two major cell fractions from the dental pulp had migrated to the RLNs at 16 hrs after cusp treatment, which showed the following lineage markers in the main and second fractions: CD11c(high)CD11b(++)Ly6C(low) Ly6G(low) F4/80(+) and CD11c(med)CD11b(+++)Ly6C(++)Ly6G(+++)F4/80(-), respectively. These lineage markers indicate that the former cells were DCs that had migrated through afferent lymphoid vessels, and the latter were granulocytes recruited via blood circulation. Migratory dental pulp DCs were mature, expressing the highest levels of CD273 (B7-DC) and CD86 co-stimulators and MHC class II. Our results suggest that cariogenic-bacteria-exposed dental pulp DCs migrate to RLNs and there trigger adaptive immune responses.

[Minimally invasive method for the restoration of localized anterior tooth wear. A case report]. / Minimál invazív módszer alkalmazása frontfogak területére korlátozott fogkopás helyreállításakor. Esetismertetés.

Wear localized on front teeth is quite common; the restoration of the lost tissue is generally difficult due to the lack of vertical space between the upper and lower teeth. The traditional prosthetic method would include further tooth preparation for complete crowns and for increasing the occlusal vertical dimension. By applying the Dahl concept the necessary vertical space can be created with the preservation of the tooth tissue in a relatively short period of time. Definitive restoration can be made for the replacement of lost enamel and dentine with a direct or indirect method. Due to the Dahl concept the preparation of the teeth and its potentially harmful consequences can be avoided, the treatment is non- or minimally invasive. In the presented case the lost palatal and incisal tooth tissue was replaced with palatal E.max Press ceramic laminate. After cementing the laminate the patient was advised to wear a night guard, because of bruxism, to counteract the extreme load on the laminates.

Restauração unitária de cerâmica em dente anterior: relato de caso / Unitary restoration of ceramic in anterior tooth: case report

Laminados de cerâmica são recomendados para dentes que exigem alto padrão estético, como os dentes anteriores, recobrindo com material estético, dentes com alteração de cor, forma ou função. Este trabalho tem como objetivo descrever a sequência clínica dos procedimentos para confecção de uma restauração unitária cerâmica em dente anterior. Paciente H.D.C., sexo feminino, 24 anos, apresentou-se à clínica do Curso de Odontologia da UFMA com queixa estética no elemento 21. No exame clínico, verificou-se a presença de escurecimento dental, causado por traumatismo. Em uma primeira sessão clínica, foi realizado procedimento de moldagem para confecção de restauração provisória posteriormente à execução do preparo. Realizou-se a seleção de cor, o preparo dentário para faceta de cerâmica pura, a moldagem do preparo e, em seguida, confeccionou-se a restauração provisória à base de bis-acrilato, com o auxílio de uma matriz de silicone. Foi realizado o acabamento e polimento da provisória. Em uma nova sessão clínica, foi realizado o ajuste da restauração cerâmica e os procedimentos de cimentação adesiva. O resultado final alcançado possibilitou a restituição da forma, função e estética adequadas

Ceramic laminate veneers are prostheses recommended to teeth that require a good aesthetic, as anterior teeth, covering with aesthetic material teeth with color, shape or function alteration. The aim of this paper is to describe the sequence of clinical procedures for making a unitary ceramic restoration in anterior tooth. Patient H.D.C., female, 24 years old, presented herself to the clinic of the Faculty of Dentistry - UFMA with esthetic complaint of the element 21. On clinical examination, there was the presence of tooth darkening, caused by trauma. It was proposed as initial treatment the manufacture of a ceramic laminate. In a single clinical session, it was performed molding procedure for making temporary restoration after the execution of the tooth preparation. We performed the color selection, preparation dental ceramic veneering, the molding of the tooth preparation and, subsequently, was made the provisional restoration with bis-acrylate, using the technique of the silicone matrix. It was conducted the finishing and polishing of the provisional restoration. The result achieved enabled the restoration of form, function and aesthetics appropriate

Reemplazo de postes metálicos por postes de base orgánica reforzados con fibras de cuarzo: presentación de un caso / Replacement of metallic posts by organic-based quartz fiber posts: report of a case

Los postes de base orgánica reforzados con fibras opseen ventajas, no sólo mecánicas, sino también estéticas. Algunas situaciones clínicas nos permiten colocar un poste de base orgánica, mientras otras nos indican la necesidad de cambiar los postes existentes. En este último caso, la técnica de desgaste centralizada constituye una alternativa clínica posible. Cuando el conduccto tiene un diámetro mayor al del poste de mayor diámetro, utilizar postes accesorios y personalizar los postes en una técnica combinada, puede resultar una solución óptima, en casos de inexistente remanente dentario coronario.

Algoritmo matemático para cuantificar directamente el ángulo de convergencia en preparaciones de dientes artificiales / Mathematical algorithm to directly quantify the convergence angle in tooth preparations dyes

El objetivo de este trabajo fue determinar un algoritmo matemático para cuantificar directamente el ángulo de convergencia (AC) en troqueles de preparaciones dentarias. El modelo experimental consistió en preparaciones coronarias simuladas sobre troqueles de yeso, en el cual el AC fue calculado por tres formulas trigonométricas. Las formulas fueron obtenidas de un modelo matemático en el cual la preparación coronaria representa una forma de pirámide truncada, la cual permite una proyección triangular en un plano. Fueron realizadas 60 mediciones in situ sobre las paredes de 15 troqueles. Se obtuvo una imagen de cada troquel usando una cámara digital (Schick® CDR). El AC fue medido usando la herramientas del software (Control). Los datos fueron analizados estadísticamente y se aplicaron test de propagación de errores. Los ángulos calculados con las tres fórmulas matemáticas ([F1], [F2] y [F3]) mostraron un alto nivel de correlación con el grupo control excepto para dos muestras. Dentro de las limitaciones de este estudio podemos concluir que a través de este algoritmo matemático, es posible cuantificar directamente el AC de las preparaciones coronarias en troqueles. Actualmente la evaluación de los AC tanto en preparaciones realizadas por alumnos de pregrado de odontología como por dentistas, se hacen de manera subjetiva. Las tres fórmulas presentadas en el algoritmo tiene una correlación alta para cuantificar el AC en troqueles. La [F3], es la que mas correlación logra en todas las muestras (0,89).

The aim of this study was to determine a mathematical algorithm to directly quantify the convergence angle (AC) dyes tooth preparations. The experimental model system consisted of crown preparations dyes simulated on plaster, which the CA was quantify by three trigonometric formulas. Formulas were obtained from mathematical models representing the crown preparation as a truncated pyramid shape, allowing a triangular projection on the plane. 60 direct measurements were made in situ on the walls of 15 dyes. An image was obtained from each dye using a digital camera (Schick ® CDR). The CA were measured using software tools (Control). The data were statistically analyzed and test data were applied to propagation of errors. The angles calculated with the three math formulas ([F1], [F2] and [F3]) showed a high level of correlation with the control except for two samples. Within the limitations of this study we can conclude that through this mathematical algorithm, it is possible to directly quantify the AC preparation coronary dyes. Currently the evaluation of AC in both preparations made by undergraduate students of dentistry as well as dentists, are made subjectively. The three formulas presented in the algorithm have a high correlation to quantify the AC dyes. The [F3], correlation is the most accomplished in all samples.

Preparos dentais para coroas totais anteriores cerâmicas / Dental preparations for anterior all-ceramic crown restorations

O objetivo deste trabalho é descrever, ilustrar clinicamente e discutir uma forma efetiva, simples e racional de preparos dentais para coroas totais anteriores cerâmicas. Essa técnica visa à confec-ção de preparos dentais por meio da utilização de número reduzido de etapas clínicas e pontas diamantadas. Os princípios biológicos, mecânicos, funcionais e estéticos são atingidos de maneira lógica, dentro dos requisitos regidos pela odontologia estética contemporânea. Ao final da leitura, espera-se que o cirurgião dentista compreenda a configuração das paredes axial e cervical dos preparos para coroas totais anteriores cerâmicas e realize o procedimento de maneira rápida e eficiente. Apesar da citação numérica específica das pontas diamantadas utilizadas, espera-se que o leitor as utilize como referência, lembrando ser mais importante a compreensão de sua configuração geométrica e volume. Outros fabricantes possuem pontas diamantadas com a mesma configuração geométrica das pontas recomendadas nesta técnica. Dessa forma, cabe ao profissional selecionar as pontas diamantadas de acordo com seu fabricante de eleição

The aim of this study is to describe, illustrate and discuss a simple, effective and rational method for preparing anterior all-ceramic restorations. This procedure uses a reduced number of diamond burs and a few clinical steps. The biological, mechanical, functional and aesthetic principles are obtained in a reasonable manner, regarding the requirements’ supported by the contemporary aesthetic dentistry. At the end of reading, it is expected that the professionals understand the design of the axial and cervical dental walls. Finally, the dental preparations will be made in a rapid and efficient manner. Despite the citation of specific diamond burs, it is expected that the reader use them as a reference. The understanding of their geometric configuration and volume are more important than their manufacturer’s reference number. Other manufacturers have diamond burs with the same geometric configuration of those recommended in this technique. Thus, the clinical professional must select the diamond points according to their manufacturer of choice

Conservative treatment of periodontal recessions with class V-defects using gingiva-shaded composite--A systematic treatment concept.

UNLABELLED: Periodontal recessions can cause aesthetic and functional problems, especially in the anterior region or when combined with exposed crown margins. A combination of periodontal disease, recession with exposed root surface, hard-tissue defects and age emphasizes the need for treating these defects. If crown margins are exposed and surgical treatment is not possible, aesthetics and function can only be improved by replacement of the restoration. The restorative treatment option with a gingiva-shaded composite is especially valuable for dental fear patients or older patients with general or local risk factors, surgical contra-indications or Class III and IV recessions with questionable prognosis of surgery. The step-by-step-approach described in this article is an alternative, minimal-invasive treatment concept for cervical lesions in combination with all kinds of periodontal recessions, that is especially suitable for wedge-shaped defects next to exposed crown margins. CLINICAL RELEVANCE: With this treatment concept, the reader should be able to use gingiva-shaded composite for different indications, such as exposed root surfaces or crown margins in combination with recessions.

Comparison of the effect of three mechanical surface treatments on the repair bond strength of a laboratory composite.

OBJECTIVE: This study compared the effects of three mechanical surface treatments, including diamond bur, air-abrasion, and Er, Cr: YSGG laser on the repair bond strength of a laboratory composite resin. BACKGROUND DATA: A proper bonding must be created between the existing composite and the new one for successful repair. MATERIALS AND METHODS: Sixty cylindrical specimens of a laboratory composite resin (Gradia) were prepared and randomly divided into four groups (n = 15). Groups 2-4 were treated with diamond bur, air-abrasion, and Er, Cr: YSGG laser, respectively; group 1 was the control group, without any mechanical surface treatment. The topographical effects of different mechanical surface treatments were characterized by atomic force microscope. Silane and a bonding agent (Single Bond) were used in all of the groups before adding a direct resin composite. Then, the specimens were subjected to a shear bond strength test. Failure modes were evaluated under a stereomicroscope. All data were analyzed by one-way ANOVA and Tukey test at a significance level of p < 0.05. RESULTS: There were statistically significant differences in bond strengths between the groups (p < 0.0005). Differences in bond strengths between group 1 and the other groups were significant (p < 0.0005). Furthermore, there were significant differences in bond strengths between group 2 and groups 3 and 4 (p < 0.0005), while the bond strength differences between groups 3 and 4 were not significant. CONCLUSION: Based on the results of this study, Er, Cr: YSGG laser was confirmed to be as effective as air-abrasion for laboratory composite repair.

Nd:YAG laser improves biocompatibility of human dental root surfaces.

OBJECTIVE: Our goal was to compare the in vivo biocompatibility of dental root surfaces submitted to four different treatments after tooth avulsion followed by implantation into rat subcutaneous tissue. BACKGROUND DATA: Dental root surface preparation prior to replanting teeth remains a challenge for endodontists. Root surface changes made by Nd:YAG irradiation could be an alternative preparation. METHODS: Forty-eight freshly extracted human dental roots were randomly divided into four treatment groups prior to implantation into rat subcutaneous tissue: G1, dry root, left in the environment up to 3 h; G2, the same treatment as G1, followed by a soaking treatment in a 2.4% sodium fluoride solution (pH 5.5); G3, root soaked in physiologic saline after avulsion for 72 h; G4, the same treatment as G1, followed by Nd:YAG laser irradiation (2.0 W, 20 Hz, 100 mJ, and 124.34 J/cm(2)). The animals were sacrificed 1, 7, and 45 d later. Histological and scanning electron microscopy analyses were done. RESULTS: All dental roots were involved and in intimate contact with connective tissue capsules of variable thicknesses. Differences were observed in the degree of inflammation and in connective tissue maturation. In G3 the inflammatory infiltrate was maintained for 45 d, whereas the Nd:YAG laser irradiation (G4) led to milder responses. The overall aspects of the root surfaces were similar, except by the irradiated roots, where fusion and resolidification of the root surface covering the dentinal tubules were observed. CONCLUSION: Nd:YAG laser irradiation improves the biocompatibility of dental root and thus could be an alternative treatment of dental root prior to replantation.

Optimizando la estética en el tratamiento de diastemas / Optimizing aesthetics in the treatment of diastemas

Los parámetros de estética dictados por la sociedad obligan a las personas a buscar cada vez más, armonía dentofacial. En consecuencia, se incrementó el número de tratamientos estéticos relacionados a cambios de forma, posición y color de los dientes. Una alteración estética de etiología múltiple, encontrada frecuentemente en la clínica odontológica, y que a menudo afecta la composición dentofacial, es el diastema anterior. La evolución...

Pinos intrarradiculares estéticos: caso clínico / Esthetics root posts: clinical case

O objetivo desse estudo foi demonstrar a técnica de utilização de pinos intrarradiculares em fibras de vidro translúcido. Foi selecionado um elemento dentário (incisivo lateral superior) de uma paciente do gênero feminino, 36 anos de idade atendida na disciplina de Dentística Restauradora da Universidade Estadual de Ponta Grossa (UEPG). O elemento dentário foi tratado endodonticamente e possuía restauração provisória deficiente. Esse procedimento foi realizado com o intuito de gerar retenção ao material restaurador definitivo e reforçar a porção coronária remanescente do elemento dentário, minimizando, assim, a probabilidade de fratura. A utilização do pino intrarradicular em fibras de vidro contribui para a manutenção da estética do elemento dentário, além de promover uma melhor distribuição das tensões nas estruturas dentárias e a retenção do material restaurador. Pinos em fibras de vidro contribuem para a estética natural dos elementos dentários.

The aim of this study was to demonstrate the technique of use of translucent glass fiber root posts. It was selected a teeth (maxilar lateral incisor) of a female patient, 36 years old assisted in the discipline of Dentistry of the State University of Ponta Grossa (UEPG). The dental element sufferred endodontics treatment and it has deficient temporary restoration. That procedure was accomplished with the intention of to generate retention to the definitive restoring material and to reinforce the remaining coronary portion of the dental element, minimizing, like this, the fracture probability. The use of the glass fiber root posts contributed to the maintenance of the aesthetics of the dental element, besides promoting a better distribution of the tensions in the dental structures and the retention of the restoring material. Glass fiber posts contribute to the natural aesthetics of the dental element.

Acid resistance of dentin after erbium:yttrium-aluminum-garnet laser irradiation.

The purpose of this study was to evaluate the acid resistance of erbium:yttrium-aluminum-garnet (Er:YAG) lased sub-surface dentin using a scanning electron microscope (SEM). Dentin disks were exposed to a single pulse of Er:YAG laser irradiation at 80 mJ/pulse under water spray, with the contact sapphire tip vertical to the dentin surfaces (n = 15). Five specimens from the laser-ablated dentin surfaces were observed. Ten specimens were crosscut, exposing the center of the lased point. For five of the specimens, the sub-surface of the lased dentin, with or without 10% phosphoric acid treatment, was evaluated. We used the remaining five specimens to analyze the degree of acid treatment on crosscut surface by observing the re-crosscut surfaces at the lased point. The irradiated dentin surfaces were irregular, scaly or flaky. Three sub-layers were observed in the sub-surface: a superficial, less decalcified layer; an intermediate most decalcified layer; and a deep, normal shade layer. Er:YAG laser irradiation affected the acid resistance of sub-surface dentin.