Evaluation of dentin microroughness and composite bond strength after multiple uses of diamond burs / Evaluación de la micro rugosidad dentinaria y la resistencia adhesiva de composites tras múltiples usos de fresas de diamante

Abstract Using a bur multiple times to prepare dental structure may produce a smoother final surface on dentin than a new one. This superficial roughness may affect adhesion with resin-based materials by modifying the substrates' characteristics. The aim of this study was to evaluate the effect of multiple uses of diamond burs on dentin's superficial microroughness and bond strength with resin composite when using a self-etch adhesive. Diamond dental burs were used to simulate a preparation (dentin flat surface) on extracted third molars. Samples were distributed into groups according to burs' number of previous uses as follows: 0, 1, 5 and 10. Scanning electron microscopy images at 70x, 350x, and 1000x were used to illustrate burs' deformation. Each specimen's dentin microroughness was measured three times to compare between experimental groups and the micro-shear bond strength test (n=15) was performed for the 0 and 10 uses groups using a universal adhesive in a self- etching mode. Diamond crystals wear and dislodgements were evident among groups where the burs were used more times. As the number of uses increased the mean microroughness of the dentin surface decreased with significant differences between the 0 and 10 uses groups. No statistical differences between experimental groups resulted from bond strength tests. When using a universal adhesive in a self-etching mode, the number of previous uses of a diamond bur seems to have no significant effect on dentin/resin composite bond strength.

Resumen El uso de una fresa múltiples veces para preparar la estructura dental puede producir una superficie final más lisa en la dentina que una fresa nueva. Esta rugosidad superficial modifica las características del sustrato y puede afectar la adhesión con materiales resinosos. El objetivo de este estudio fue evaluar el efecto de los múltiples usos de las fresas de diamante sobre la micro rugosidad superficial de la dentina y la resistencia adhesiva con la resina compuesta cuando se utiliza un adhesivo de autograbado. Se utilizaron fresas dentales de diamante para simular una preparación (superficie plana de la dentina) en terceros molares extraídos. Las muestras se distribuyeron en grupos según el número de usos previos de las fresas de la siguiente manera: 0, 1, 5 y 10. Se utilizaron imágenes de microscopía electrónica de barrido a ×70, ×350 y ×1000 para ilustrar la deformación de las fresas. Se midió la micro rugosidad de la dentina de cada espécimen tres veces para comparar entre los grupos experimentales y se realizó la prueba de resistencia a la adhesión por micro cizallamiento (n=15) para los grupos de 0 y 10 usos utilizando un adhesivo universal en modo de autograbado. El desgaste de los cristales de diamante y los desprendimientos fueron evidentes entre los grupos en los que las fresas se utilizaron más veces. A medida que aumentaba el número de usos, la micro rugosidad media de la superficie de la dentina disminuyó, con diferencias significativas entre los grupos de 0 y 10 usos. En las pruebas de resistencia adhesiva no se observaron diferencias estadísticas entre los grupos experimentales. Cuando se utiliza un adhesivo universal en modo de autograbado, el número de usos previos de una fresa de diamante no parece tener un efecto significativo en la resistencia de la unión dentina/resina del composite.

Finishing and polishing effects of multiblade burs on the surface texture of 5 resin composites: microhardness and roughness testing

OBJECTIVES: The aim of this in vitro study was to test the effect of 2 finishing–polishing sequences (QB, combining a 12/15-fluted finishing bur and an EVO-Light polisher; QWB, adding a 30-fluted polishing bur after the 12/15-fluted finishing bur used in the QB sequence) on 5 nanotech-based resin composites (Filtek Z500, Ceram X Mono, Ceram X Duo, Tetric Evoceram, and Tetric Evoceram Bulk Fill) by comparing their final surface roughness and hardness values to those of a Mylar strip control group (MS). MATERIALS AND METHODS: Twelve specimens of each nanocomposite were prepared in Teflon moulds. The surface of each resin composite was finished with QB (5 samples), QWB (5 samples), or MS (2 samples), and then evaluated (60 samples). Roughness was analysed with an optical profilometer, microhardness was tested with a Vickers indenter, and the surfaces were examined by optical and scanning electron microscopy. Data were analysed using the Kruskal-Wallis test (p < 0.05) followed by the Dunn test. RESULTS: For the hardness and roughness of nanocomposite resin, the QWB sequence was significantly more effective than QB (p < 0.05). The Filtek Z500 showed significantly harder surfaces regardless of the finishing–polishing sequence (p < 0.05). CONCLUSIONS: QWB yielded the best values of surface roughness and hardness. The hardness and roughness of the 5 nanocomposites presented less significant differences when QWB was used.

Sterilisation Of Rotary Cutting Instruments – A Survey On Current Practices

Aim: The aim of this study was to obtain the information regarding present sterilization procedures followed for sterilizing Rotary cutting instruments or burs in routine dental practices using a Questionnaire and to assess the effectiveness of those procedures in preventing cross infection, and to recommend an effective sterilization protocol to be followed while using rotary cutting dental burs. Materials and Methods: A questionnaire which was pre-validated was used to collect the information regarding the methods followed to sterilize the rotary cutting instruments in 100 dental clinics in and around Hyderabad and the effectiveness of those methods were analyzed using descriptive analysis. Results: The procedures undertaken by our clinicians in their day to day practice to resterilize rotary cutting burs are poorly effective, the risk of cross-infection is very high with those methods. Conclusion: The cleaning and resterilization procedures of rotary cutting instruments that were followed regularly in clinical practice were not adequate, and more rigorous procedures are needed. If such procedures cannot be devised, these instruments should perhaps be considered single-use devices.

Influence of reused dental burs on bond strength to dentin

AIM: this study evaluated the bond strength of an adhesive system to human dentin prepared with reused diamond burs. MATERIAL AND METHODS: five molars (G1) were prepared in a standardized way with five diamond burs. Flat deep dentin surfaces were etched, received adhesive and received composite build-ups. The same burs were cleaned and reused on another five teeth groups (G2 until G8). After 24-hours storage and thermocycling, 50 dentin-resin sticks per group were obtained and subjected to microtensile bond strength test (µTBS). RESULTS: analysis of variance (ANOVA) and Tukey test were applied to identify differences between groups (p<0.05). The reuse of a diamond bur for more than two preparations resulted in significantly lower µTBS values (G1 = G2 > G3 = G4 = G5 = G6 = G7 = G8). CONCLUSION: Reuse of diamond burs interfered on adhesion between dentin and resin.

Análise das dimensões padrões das macrogeometrias de pontas diamantadas de diferentes fabricantes e modelos / Analysis of the macrogeometry pattern dimensions of diamond burs of different manufacturers and models

Pontas diamantadas são instrumentos rotatórios abrasivos de uso rotineiro na prática clínica odontológica, com macrogeometria constituída de haste metálica, ponta ativa e eixo Intermediá- rio. Objetivo: avaliar as dimensões padrões dos componentes que constituem a macrogeometria das pontas diamantadas. Material e Método: a fim de padronização, considerou-se como ponta ativa a região do instrumental que possui granulação; como eixo Intermediário a região compreendida entre a primeira depressão presente na base até o início da ponta ativa; e como haste metálica toda região localizada entre a base da ponta diamantada até a primeira depressão. Realizou os testes com seis marcas comerciais: KG Sorensen, Option, Vortex, Microdont, Zeep e Fava. Foram selecionadas 120 pontas diamantadas tronco-cônicas, modelos 2200 (n=10) e 2135 (n=10). O diâmetro e comprimento foram analisados em sete regiões correspondentes à macrogeometria. O diâmetro do orifício de encaixe de pontas diamantadas em turbinas de alta rotação de cinco marcas (Gnatus, Kavo, Calu, Dx e Dabi) também foi mensurado. Para realizar as medidas, paquímetro digital (Mitutoyo, modelo número 6, C-B) foi utilizado por um único operador calibrado. Resultado: as dimensões de ambos os modelos de pontas diamantadas apresentaram variação, quando comparado os fabricantes, seja no comprimento total da haste metálica, eixo intermediário ou ponta ativa. A marca comercial KG Sorensen apresentou baixa alteração na dimensão entre seus instrumentos. Conclusão: a não padronização das pontas diamantadas pode prejudicar a confecção de preparos e também o aprendizado de estudantes de odontologia.

Diamond burs are abrasive rotary instrumental routinely used in clinical dentistry practice with macro geometry consists of metal stem, the active tip and intermediate shaft. Objective: evaluate the standardized dimensions of the components that constitute the macro geometry of the diamond bur. Methods: in order to standardize, it was considered as active tip the area of the diamond bur that has granulation; as intermediate the region between the first depression at the base until the beginning of the active tip; and as stem all region located between the base of the diamond tip to the first depression. The test was performed with six brand: KG Sorensen, Option, Microdont, FAVA, Zeep, Vortex. 120 trunk-conical diamond burs, models 2200 (n = 10) and 2135 (n = 10) were selected. The diameter and length were evaluated in seven regions corresponding to macro geometry. The diameter of the diamond bur orifice fitting on the high speed turbines of five brands (Gnatus, Kavo, Calu, Dx and Dabi) were also measured. A digital caliper (Mitutoyo, modelo número 6, C-B) was used for measurements by a single calibrated operator. Results: the dimensions of both models showed variation compared trademarks, either in the total length of the metal stem, active tip or intermediary. KG Sorensen trademark presented low alterations in size between their instruments. Conclusion: the non-standardized of diamond burs can hamper the confection of preparations and also the learning of dental students.

The experiment study of several resin-removal methods on enamel surface / 重庆医学

Objective To observe the effect of several residual adhesive methods on the enamel surface ,and conduct lab evalua-tion .Methods Sixty premolars extracted because of orthodontic treatment .And all the teeth were randomly divided into 3 groups . Group 1:tungsten carbide burs + silicon particles ;Group 2 :ultrasonic scaling + silicon particles ;Group 3:silicon particles ,each with 20 premolars .After underwent several methods ,the surface roughness differences ,operation time were determined and ob-served with the scanning electron microscope .And the result was statistically analyzed .Results There were significant differences in the surface roughness and operation time among the three groups (P<0 .05) ,The scanning electron microscope after polishing showed that the teeth surface had different degrees of injury ,the silica particles group had less superficial scratch .Conclusion The tungsten carbide burs and ultrasonic instrument for debonding before the silica particles had less superficial scratch .

Comparison of different wear burs after cavity preparation and sterilization methods / Comparação do desgaste de diferentes pontas após preparo cavitário e diferentes métodos de esterilização

Objetivo: Avaliar a perda estrutural e alteração morfológica da superfície de diferentes instrumentos de corte após preparo cavitário e diferentes métodos de esterilização. Material e Método: Cavidades padronizadas na superfície vestibular de incisivos bovinos foram realizadas na região do limite cemento-esmalte usando cinco diferentes tipos de instrumentos de corte (n= 4): Ca- broca cilíndrica Carbide #56 (KG Sorensen), Kg- ponta diamantada cilíndrica #1093 (KG Sorensen), Mi- ponta diamantada cilíndrica #1093 (Microdont), Fa- ponta diamantada cilíndrica #1093 (Fava) e Cv- ponta diamantada cilíndrica artificial #8,2137 (CVDentUS). Cada ponta foi submetida a um ciclo que envolveu a realização de microscopia eletrônica de varredura (MEV) inicial, preparo cavitário (PC), limpeza com ultrassom (US), três métodos de esterilização: glutaraldeído a 2% (Gl), estufa - calor seco (DH) ou autoclave - calor úmido (WH), e MEV final. Resultados: Foram encontradas diferenças significativas para a interação entre os fatores. Conclusão: O método de esterilização modifica estruturalmente os instrumentos de corte de modo diferente entre os tipos de instrumentos testados. O glutaraldeído foi o método que apresentou pior resultado para as brocas carbides. As pontas diamantadas apresentaram grande variabilidade de resultados para a interação dos fatores desgaste de instrumentos de corte e processos de esterilização.

Objective: evaluate the loss of mass and the morphologic surface alteration of different cutting instruments after cavity preparation from dental structure and different methods of sterilization. Material and Method: standardized cavities in the buccal surface of bovine incisors had been carried through in the region of the limit enamel-cementum using five different types of cut instruments (n=4): Ca- cylinder carbide bur #56 (KG Sorensen), Kg- cylindrical diamond bur #1093 (KG Sorensen), Mi- cylindrical diamond bur #1093 (Microdont), Fa- cylindrical diamond bur #1093 (Fava) and Cv- cylindrical artificial diamond bur #8.2137 (CVDentUS). Each tip was submittes to a cycle that involved: Initial Scanning Electron Microscopy (SEM), cavity preparation (PC), clean-up ultrasonic (US), three methods of sterilization: glutaraldehyde 2% (Gl), dry heat (DH) or wet heat (WH) and final SEM. Results: significant difference for the interaction between factors was found. Conclusion: the sterilization method modifies structurally the cut instruments in different way among types of the instruments tested. Glutaraldehyde proved to be the worst method for sterilizing carbide bur. The diamond instruments showed great variability of results for the interaction of wear of cutting instruments and sterilization processes.

Wear of Rotary Instruments: A Pilot Study

The aim of this study was to assess the wear of tungsten carbide burs and round rotary diamond instruments through measurements of rake angle and visual observations respectively under a f ield emission scanning electron microscope. Sixty short and long head pear-shaped tungsten carbide burs and 18 round rotary diamond instruments that had been used to complete 5 and > 10 cavity preparations (n=10/ group) were selected from the 3rd and 4th year dental students, Faculty of Dentistry, University of Malaya. There were two control groups consisting of long and short tungsten carbide burs of ten each. Two-way ANOVA was used to analyse the rake angle data. The data from the two control groups were collectively analysed following multiple paired t-test (p > .05) which showed no significant difference between the two types of tungsten carbide bur (short and long head). The mean rake angle of the control group was significantly higher (p 5 and > 10 cavity preparation groups. The rake angle of the > 10 cavity preparation group was significantly lower than the other two test groups (p 5 and > 10 cavity preparation groups showed blunt diamond particles. In conclusion, wear of tungsten carbide burs and round rotary diamond instruments were evident after repeated use. Wear was more pronounced when instruments were used to prepare more than ten cavities.

Effect of cutting instruments on the dentin bond strength of a self-etch adhesive / 대한치과보존학회지

The purpose of this study was to compare the microshear bond strength of a self-etching primer adhesive to dentin prepared with different diamond points, carbide burs and SiC papers, and also to determine which SiC paper yield similar strength to that of dentinal surface prepared with points or burs. Fifty-six human molar were sectioned to expose the occlusal dentinal surfaces of crowns and slabs of 1.2 mm thick were made. Dentinal surfaces were removed with three diamond points, two carbide burs, and three SiC papers. They were divided into one of eight equal groups (n = 7); Group 1: standard diamond point(TF-12), Group 2: fine diamond point (TF-12F), Group 3: extrafine diamond point (TF-12EF), Group 4: plain-cut carbide bur (no. 245), Group 5: cross-cut carbide bur (no. 557), Group 6 : P 120-grade SiC paper, Group 7: P 220-grade SiC paper, Group 8: P 800-grade SiC paper. Clearfil SE Bond was applied on dentinal surface and Clearfil AP-X was placed on dentinal surface using Tygon tubes. After the bonded specimens were subjected to uSBS testing, the mean uSBS (n = 20 for each group) was statistically compared using one-way ANOVA and Tukey HSD test. In conclusion, the use of extrafine diamond point is recommended for improved bonding of Clearfil SE Bond to dentin. Also the use of P 220-grade SiC paper in vitro will be yield the results closer to dentinal surface prepared with fine diamond point or carbide burs in vivo.

CVD (Chemical Vapor Deposition) - solução para controle de temperatura durante preparo cavitário? / CVD (Chemical Vapor Deposition) - solution for control of temperature during cavity preparation?

Os procedimentos restauradores em Odontologia utilizam brocas, turbinas de alta rotação, laser e novas tecnologias, como as pontas diamantadas obtidas pelo processo de deposição química a vapor (CVD). O uso incorreto desses métodos pode gerar aquecimento excessivo e agredir o complexo dentinopulpar, provocando lesões que variam de leve à grave e até mesmo a necrose da polpa. O objetivo deste trabalho foi revisar e discutir o aumento de temperatura no complexo dentinopulpar durante o preparo cavitário, causado pelas brocas diamantadas convencionais usadas em turbina de alta rotação, pelo laser e pelas pontas diamantadas CVD acopladas ao ultrassom. Treze estudos foram encontrados após busca na base de dados PubMed no período de 1998 a 2009, sendo quatro relacionados a brocas diamantadas em turbinas de alta rotação, sete acerca de sistemas a laser e dois sobre as pontas CVD. De acordo com a literatura científca pesquisada, pode-se concluir que nenhum dos métodos aumenta a temperatura a ponto de causar injúria pulpar irreversível. Porém, não há estudos suficientes publicados para se afirmar que as pontas diamantadas CVD apresentam-se como a solução para controle do aumento de temperatura durante o preparo cavitário.

The restorative procedures in dentistry use burs, high-speed handpieces, laser and new technologies such as diamond burs obtained by the process of chemical vapor deposition (CVD). The misuse of these methods can generate excessive heat, and harm the pulpodentin complex, causing injuries ranging from mild to severe and even necrosis of the pulp. The objective was to review and discuss the temperature increase in pulpodentin complex during cavity preparation, caused by conventional diamond burs used in high-speed handpieces, laser and the CVD ultrasound diamond burs. Thirteen studies were found after a search on PubMed database from 1998 to 2009, and 4 were related to diamond burs at high-speed handpieces, 7 about laser systems and 2 about the CVD burs. According to the researched literature, we can conclude that none of the methods increases the temperature to the point of causing irreversible injury on the pulp. However, there are not enough published studies that confrm CVD diamond burs as the solution to controlling the temperature increase during cavity preparation.