Antimicrobial activity of Er, Cr: YSGG and Ultrasonic on E. faecalisbiofilm in the mesial root canal systems of lower molars / Atividade antimicrobiana de Er, Cr: YSGG e Ultrassônico no biofilme de E. faecalis nos sistemas de canais radiculares mesiais de molares inferiores

The internal topography of the root canal is complex, especially for the permanent molar's mesial root. In response to such issues, improved irrigation techniques have been created, which use laser pulses to agitate fluids and improve microbial deposit removal. Objective: To assess the effectiveness of the Er,Cr:YSGG laser with a wavelength of 2,780 nm via photon-induced photoacoustic streaming (PIPS) protocol which agitated of 2% chlorohexidine (CHX) in removing mature Enterococcus faecalis (E. faecalis) biofilm in root canal systems of lower molars. Material and Methods: The mesial roots of lower first and second molars were separated and inoculated with E. faecalis bacterial suspension for 30 days. The roots were irrigated with CHX, some of them were agitated with a passive ultrasonic device (PUI), while the other roots were agitated by an Er,Cr:YSGG laser in PIPS at 60 µs/pulse, 5 Hz, (0.25, 0.5, 0.75, and 1) W. An atomic force microscope (AFM) was used as a new method to get the results in the isthmus area; the obtained results from each group were compared with each other. Results: Based on the AFM and SEM analyses, laser and ultrasonic activation groups showed higher antimicrobial efficacy than the conventional syringe irrigation group (P<0.05). Conclusion: Based on the investigation's findings, the activation of 2% CHX solution by Er,Cr:YSGG laser in PIPS and PUI offers better mature bacterial biofilm removal in the mesial root of lower human molars than the same irrigant with the SI technique (AU)

A topografia interna do canal radicular é complexa, especialmente para a raiz mesial do molar permanente. Em resposta a esses problemas, foram criadas técnicas aprimoradas de irrigação, que utilizam pulsos de laser para agitar fluidos e melhorar a remoção de depósitos microbianos. Objetivo: Avaliar a eficácia do laser Er,Cr:YSGG com comprimento de onda de 2.780 nm via protocolo de streaming fotoacústico induzido por fótons (PIPS) que agitou clorohexidina a 2% (CHX) na remoção de Enterococcus faecalis maduro (E. faecalis) biofilme em sistemas de canais radiculares de molares inferiores. Material e Métodos: As raízes mesiais de 28 primeiros e segundos molares inferiores foram separadas e inoculadas com suspensão bacteriana de E. faecalis por 30 dias. As raízes foram irrigadas com CHX, sendo algumas delas agitadas com aparelho ultrassônico passivo (PUI), enquanto as demais raízes foram agitadas com laser Er,Cr:YSGG em PIPS a 60 µs/pulso, 5 Hz (0,25, 0,5, 0,75 e 1) W. Um microscópio de força atômica (AFM) foi utilizado como um novo método para obter os resultados na área do istmo; os resultados obtidos de cada grupo foram comparados entre si. Resultados: Com base nas análises de AFM e SEM, os grupos de ativação por laser e ultrassom apresentaram maior eficácia antimicrobiana do que o grupo de irrigação com seringa convencional (P<0.05). Conclusão: Com base nos achados da investigação, a ativação da solução de CHX a 2% pelo laser Er,Cr:YSGG em PIPS a (60 µs/pulso, 5 Hz, 0,75 W) oferece melhor remoção de biofilme (AU)

Effect of cavity disinfection protocols on microtensile bond strength of universal adhesive to dentin / Efecto de los protocolos de desinfección de cavidades en la fuerza de adhesión microtensil del adhesivo universal a la dentina

Abstract The purpose of this study was to compare the effect of different disinfection protocols of dentin on bond strength of an MDP-containing universal adhesive. Twelve extracted mandibular third molars were separated horizontally at the mid-coronal of crown to get smooth and sound dentin surfaces using low-speed diamond saw. The teeth were randomly fallen into four groups: chlorhexidine (CHX), ozone, Er,Cr:YSGG laser irradiation (LASER) and no treatment (control). After cavity disinfection application, a universal adhesive (G-Premio Bond) was applied to the surface of dentin according to self-etch mode as instructed by the manufacturer. After incremental built-up of composite resin (Charisma Smart), the specimens were immersed in distilled water at 37°C for 24h. Dentin/composite beams with 1 mm² cross sectional area were produced and micro-tensile bond strength (µTBS) was applied on these beams (n=20). Failure mods were determined under a stereomicroscope at ×40. The resin penetration of samples stained with Rhodamine B fluorochrome dye was examined with a confocal laser scanning microscope. Statistical analysis was performed with SPSS-22. Test results were analyzed using One-way Anova and Tukey HSD Post-Hoc tests (p0.5). All applications of cavity disinfection procedures decreased the µTBS of the resin-dentin interface.

Resumen El propósito de este estudio fue comparar el efecto de diferentes protocolos de desinfección de la dentina sobre la fuerza de unión de un adhesivo universal que contiene MDP. Doce terceros molares mandibulares extraídos se quebraron horizontalmente en la mitad de la corona para obtener superficies de dentina lisas y sólidas utilizando una sierra de diamante de baja velocidad. Los dientes se dividieron aleatoriamente en cuatro grupos: clorhexidina (CHX), ozono, irradiación con láser Er,Cr:YSGG (LASER) y ningún tratamiento (control). Después de la aplicación de la desinfección de la cavidad, se aplicó un adhesivo universal (G-Premio Bond) a la superficie de la dentina según el modo de autograbado indicado por el fabricante. Después de la obturación con resina compuesta (Charisma Smart), las muestras se sumergieron en agua destilada a 37°C durante 24h. Se produjeron porciones de dentina/resina con un área de sección transversal de 1 mm² y se aplicó una fuerza de adhesión microtensile (µTBS) (n=20). Los modos de falla se determinaron bajo un microscopio estereoscópico a ×40. La penetración de la resina de las muestras teñidas con colorante fluorocromo rodamina B se examinó con un microscopio de barrido láser confocal. El análisis estadístico se realizó con SPSS-22. Los resultados de las pruebas se analizaron utilizando las pruebas post-hoc Anova unidireccional y Tukey HSD (p0.5). Todas las aplicaciones de procedimientos de desinfección de cavidades redujeron el µTBS de la interfaz resina-dentina.

Erbium laser in the debonding of ceramics: a literature review / Laser de érbio na remoção de cerâmicas: uma revisão de literatura

Background: The debonding of crowns and ceramic veneers with laser is already a reality in the clinic. It presents benefits in comparison to traditional removal with the use of a rotating instrument; however, there is still no consolidated protocol and many professionals use it without the necessary scientific basis. Objective: The aim of this work was to perform a literature review on the debonding of indirect ceramic restorations using the Er:YAG and Er,Cr:YSGG lasers to provide clinical professionals and the scientific community a careful analysis, and also to guiding the use of irradiation at laser for such procedures. Methods: Bibliographic searches were performed in the following databases: Pubmed, Web of Science and Google Scholar. According to the inclusion criteria adopted, twenty-seven clinical and in vitro studies were selected in the period from 2007 to 2021. In the present work, the composition of the crowns and facets, as well as the types of cement and the laser irradiation protocols adopted in the selected studies is detailed. Conclusions: It was concluded that the use of erbium lasers for debonding of indirect ceramic restorations proved to be more selective and conservative when compared to removal with a rotary diamond instrument. Furthermore, it was shown to be in more efficient in debonding different types of ceramics. However, there are great variations in the "debonding" protocols, which emphasizes the need for further studies that seek to standardize the irradiation protocols considering the different clinical situations (AU)

Antecedentes: A remoção de coroas e facetas cerâmicas com laser já é uma realidade clínica e apresenta benefícios em relação à remoção tradicional com uso de instrumento rotatório diamantado; entretanto, ainda não existe um protocolo consolidado e muitos profissionais o utilizam sem o embasamento científico necessário. Objetivos: O objetivo deste trabalho foi realizar uma revisão da literatura sobre a remoção de restaurações cerâmicas indiretas utilizando os lasers Er:YAG e Er,Cr:YSGG para fornecer uma análise cuidadosa aos profissionais clínicos e à comunidade científica, além de orientar o uso da irradiação a laser para tal aplicação. Métodos: As buscas bibliográficas foram realizadas, nas seguintes bases de dados: Pubmed, Web of Science e Google Scholar. De acordo com os critérios de inclusão adotados, foram selecionados vinte e sete estudos clínicos e in vitro no período de 2007 a 2021. No presente trabalho, a composição das coroas e facetas, bem como os tipos de cimento e os protocolos de irradiação laser adotados nos estudos selecionados foram detalhados. Conclusão: Concluiu-se que o uso dos lasers de érbio para remoção de restaurações cerâmicas indiretas mostrou-se mais seletivo e conservador quando comparado à remoção com instrumento rotatório diamantado, além de ser eficiente na remoção de diferentes tipos de cerâmicas. No entanto, existem grandes variações nos protocolos de "debonding", o que enfatiza a necessidade de novos estudos que busquem uma padronização dos protocolos de irradiação considerando as diferentes situações clínicas.(AU)

Bond Strength Evaluation of Bulk- fill Composites to Dentin Under Different Surface Treatments / Evaluación de la resistencia adhesiva de las resinas bulk-fill a la dentina con diferentes tratamientos de superficie

ABSTRACT: Purpose: The aim of this study is to compare the shear bond strength of three high-viscosity bulk-fill composite resins applied as single layers of 4mm thickness and of one microhybrid composite resin applied incrementally with a thickness of 2mm on dentin surfaces prepared with different surface preparation methods. Materials and Methods: A total of 132 caries-free human molars whose dentines had been exposed were used. Three groups, each containing 44 teeth, were formed. The acid group was etched with 32% phosphoric acid; laser group was etched with Er, Cr; YSGG laser and the control group was prepared with silicon carbid paper. Following the application of bonding agent, composite resin materials were applied on teeth using teflon moulds of 4x4mm. The samples were then subjected to shear bond strength tests. Two-way variance analysis and Tukey HSD multiple comparison test were applied on collected data. Results: There was a significant difference between surface treatment methods used regarding shear bond strength (P0.05). Conclusions: Laser etching of the dentin tissues is not as effective as acid etching. Bulk-fill composites had similar effects compared with conventional composite resins with regard to bonding strength. More in vitro studies supported with clinical data are required to investigate the performance of bulk-fill composites and laser.

RESUMEN: Propósito: El objetivo de este estudio es comparar la resistencia adhesiva al cizallamiento de tres resinas compuestas de relleno de alta viscosidad aplicadas como capas individuales de 4 mm de espesor y de una resina compuesta microhíbrida aplicada de forma incremental con un espesor de 2mm en superficies de dentina preparadas con diferentes métodos de preparación de la superficie. Materiales y métodos: Se utilizaron un total de 132 molares humanos sin caries cuyas dentinas habían sido expuestas. Se formaron tres grupos, cada uno con 44 dientes. El grupo ácido se grabó con ácido fosfórico al 32%; el grupo láser se grabó con Er, Cr; el láser YSGG y el grupo de control se preparó con papel de carburo de silicio. Después de la aplicación del agente adhesivo, se aplicaron materiales de resina compuesta en los dientes utilizando moldes de teflón de 4x4mm. A continuación, las muestras se sometieron a pruebas de resistencia adhesiva al cizallamiento. Se aplicó el análisis de varianza bidireccional y la prueba de comparación múltiple Tukey HSD a los datos recogidos. Resultados: Hubo una diferencia significativa entre los métodos de tratamiento de superficie utilizados en cuanto a la resistencia adhesiva al cizallamiento (P0,05). Conclusiones: El grabado láser de los tejidos de la dentina no es tan eficaz como el grabado al ácido. Las resinas de relleno bulk-fill tuvieron efectos similares en comparación con las resinas compuestas convencionales en lo que respecta a la rsistencia adhesiva. Se necesitan más estudios in vitro apoyados con datos clínicos para investigar el rendimiento de los composites de relleno y el láser.

Application research progress of Er，Cr：YSGG laser in root canal therapy / 口腔疾病防治

@#Erbium，chromium：yttrium scandium gallium garnet（Er，Cr：YSGG）laser is mainly used for root canal treatment，periodontal disease，tooth decay，dentin hypersensitivity，pulp amputation，etc in the field of dentistry.This paper mainly describes the research progress of Er，Cr：YSGG laser in root canal therapy from following four as⁃pects：root canal sealing，sterilization，cavitation effect and the effect on periapical tissue. The experimental results showed that when the operation parameters of Er，Cr：YSGG were 2 ~ 4 w and 20 Hz，it could effectively remove the stained layer of dentin tubules and improve the tightness between materials and dentin. The thermal effect produced by Er，Cr：YSGG energy has a sterilizing effect，while the optical conductivity of the tooth enables the rinse solution to enter deeper tissues，further improving the sterilizing effect. Er，Cr：YSGG also has a cavitation effect，which destroys the surface tension of the deep solution，removing the stain layer and bacteria in the deep layer. However，with the same operation parameters，if Er，Cr：YSGG is not used properly，the thermal effect of Er，Cr：YSGG will cause some damage to the periapical tissues. Therefore，reasonable use time of Er，Cr：YSGG and water cooling conditions are important.

Effect of Surface Treatment of Two Ceramic Materials by Er, Cr:YSGG Laser Irradiation on The Shear Bond Strength to Resin Cement: "a Comparative in-Vitro Study" / Efeito do tratamento de superfície de dois materiais cerâmicos por Irradiação de laser Er, Cr:YSGG na resistência ao cisalhamento a cimento Resinoso: "um estudo comparativo in-Vitro"

Objective: The aim of this study is to assess the effect of Er,Cr:YSGG laser on the shear bond strength (SBS) and surface topography of two CAD/CAM ceramic materials bonded with self adhesive resin cement. Material and methods: sixty ceramic CAD/CAM discs were obtained, 30 lithium disilicate (IPS Emax) (Group LD), and 30 hybrid resin ceramic (Vita Enamic) (Group RC). The Slices were allocated into six groups (n=10) according to ceramic material and surface treatment; Group (LD-C): IPS Emax treated with 9% hydrofluoric acid (HF), Groups (LD-L1) and (LD-L2): IPS Emax treated with Er,Cr:YSGG, Group (RC-C): Vita Enamic treated with 9% hydrofluoric acid (HF), Groups (RC-L1) and (RC-L2): Vita Enamic treated with Er,Cr:YSGG laser. The laser parameters and irradiation protocol was 1.5 W (L1) and 2.5 W (L2). All samples were cemented with self-adhesive resin cement and thermocycled for 5000 cycles. The SBS was measured using a universal testing machine and the mean values (MPa) were analyzed using Two-way (ANOVA) (P ≤ 0.05) and Bonferroni's post-hoc test. Results: RC-C (16.55) showed highest SBS followed by LD-C (13.79), which revealed no statistically significant difference with RCP1 (12.33) and RC-P2 (11.2). The lowest SBS values were found with LD-P1 (2.7) and LDP2 (2.1). SEM analysis revealed Vita Enamic to have the highest surface roughness. Fracture pattern analysis showed adhesive failure with IPS Emax groups and mixed failure with Vita Enamic groups. Conclusion: Er,Cr:YSGG laser irradiation with the parameters used did not increase SBS of IPS Emax and Vita Enamic with composite resin compared to HF acid etching (AU)

Objetivo: O objetivo deste estudo é avaliar o efeito do laser Er,Cr:YSGG na resistência ao cisalhamento (SBS) e na topografia superficial de dois materiais cerâmicos CAD/CAM cimentados com cimento resinoso autoadesivo. Material e métodos: foram obtidos sessenta discos cerâmicos CAD/CAM, 30 de dissilicato de lítio (IPS Emax) (Grupo LD) e 30 de resina híbrida (Vita Enamic)(Grupo RC). Os discos foram alocados em seis grupos (n = 10), de acordo como material cerâmico e o tratamento de superfície; Grupo (LD-C): IPS Emaxtratado com ácido fluorídrico (HF) a 9%, Grupos (LD-L1) e (LD-L2): IPS Emaxtratado com Er,Cr:YSGG, Grupo (RC-C): Vita Enamic tratada com ácido fluorídrico (HF) a 9%, Grupos (RC-L1) e (RC-L2): Vita Enamic tratada com laser Er,Cr:YSGG. Os parâmetros do laser e o protocolo de irradiação foram de 1,5 W (L1) e 2,5 W (L2). Todas as amostras foram cimentadas com cimento resinoso autoadesivo e termocicladas por 5000 ciclos. A SBS foi medida usando uma máquina de ensaios universais e os valores médios (MPa) foram analisados usando (ANOVA) a dois fatores (P ≤ 0,05) e teste post-hoc de Bonferroni. Resultados: RC-C (16,55) apresentou maior SBS seguido por LD-C (13,79), que não revelou diferença estatisticamente significante com RCP1(12,33) e RC-P2 (11,2). Os menores valores de SBS foram encontrados comLD-P1 (2,7) e LD-P2 (2,1). A análise por MEV revelou que a Vita Enamic possui maior rugosidade de superfície. A análise do padrão de fratura mostrou falha adesiva nos grupos IPS Emax e falha mista nos grupos Vita Enamic. Conclusão: A irradiação com laser Er,Cr:YSGG com os parâmetros utilizados não aumentou a SBS de IPS Emax e Vita Enamic ao cimento resinoso em comparação com o condicionamento ácido com HF.(AU)

Influence of Er, Cr: Ysgg Laser Associated or not To 5% Fluoride Varnish in the Erosion Treatment of Bovine Enamel / Influência do Laser Er, Cr: Ysgg Associado ou não ao Verniz Fluoretado 5% no Tratamento da Erosão em Esmalte Bovino

The objective of this in vitro study was to evaluate the influence of the Er,Cr:YSGG laser associated or not to a desensitizing agent in the treatment of erosive lesions. Forty specimens with dimensions of 4mm x 4mm and 3mm thickness were divided into 4 groups (n = 10): G1- no treatment; G2- 5% fluoride varnish; G3- Er,Cr: YSGG; G4 - fluoride varnish + laser. The specimens were immersed in erosive drink 3 times a day for 1 minute with an average interval of 2 hours between cycles for a period of 10 days. The treatments were performed according to the groups and the surface roughness and the wear profile were analyzed by scanning confocal microscopy. The normality (Kolmogorov-Smirnov) and homogeneity (Levene's) of the tests were evaluated. After these analyzes, the surface roughness data were submitted to the statistical analysis of Variance Analysis (ANOVA). All tests adopted a significance level of 5% (α = 0.05). At the representative images of the wear profile, the morphology of bovine dental enamel in its control and eroded areas were compared and qualitatively discussed. As regard surface roughness, there was no statistically significant difference between the groups. The qualitative analysis of the loss of volume showed that all experimental groups showed significant superficial morphology differences. Considering the limitations of an in vitro study, it can be concluded that the treatments performed were not able to treat dental erosion satisfactorily, indicating the need for more treatment sessions. (AU)

O objetivo desse estudo in vitro foi avaliar a influência do laser Er,Cr:YSGG associado ou não a um agente dessensibilizante no tratamento de lesões erosivas. Foram confeccionados 40 espécimes com dimensões de 4mm x 4mm e 3mm de espessura, divididos em 4 grupos (n=10): G1- nenhum tratamento; G2- verniz fluoretado 5%; G3- aplicação do laser Er,Cr:YSGG; G4- verniz fluoretado + laser. Os espécimes foram imersos em bebida erosiva, 3 vezes por dia, durante 1 minuto, com intervalo médio de 2 horas entre os ciclos, por um período de 10 dias. Os tratamentos foram realizados de acordo com os grupos e que foram analisados a rugosidade superficial e o perfil de desgaste por meio de microscopia confocal de varredura. Avaliou-se a normalidade (Kolmogorov-Smirnov) e homogeneidade (Levene's) dos dados. Após estas análises, os dados de rugosidade superficial foram submetidos ao teste estatístico de Análise de Variância (ANOVA). Todos os testes adotaram nível de significância de 5% (α=0,05). Através da obtenção das imagens representativas do perfil desgaste, a morfologia do esmalte dental bovino em suas áreas controle e erodida foram comparadas e qualitativamente discutidas. Quanto à rugosidade superficial, não houve diferença estatisticamente significativa entre os grupos. A análise qualitativa da perda de volume mostrou que todos os grupos experimentais apresentaram diferenças significativas na morfologia superficial. Considerando as limitações de um estudo in vitro pode-se concluir que os tratamentos realizados não foram capazes de tratar a erosão dentária de forma satisfatória, indicando a necessidade de mais sessões de tratamento.

Short-term clinical efficacy observation of adjunctive Er, Cr:YSGG laser application following subgingival scaling in patients with severe periodontitis / 上海交通大学学报（医学版）

Objective · To observe the short-term clinical efficacy of adjunctive Er, Cr:YSGG laser application following subgingival scaling in patients with severe periodontitis. Methods · In this parallel control design clinical trial, 46 patients with severe periodontitis were selected. Baseline examination was performed 2 weeks after supragingival scaling. Then the patients were randomly divided into the test group and the control group, with 23 cases in each group. After ultrasonic subgingival scaling, sites with probing depth (PD) ≥5 mm of patients in two groups received subgingival debridement with Er, Cr:YSGG laser and hand curettes, receptively. The changes in plaque index (PLI), PD, clinical attachment level (CAL), the percentage of bleeding on probing (BOP) positive sites, and the degree of subjective pain during treatment with visual analogue scale (VAS) were compared between two groups at baseline, 6 weeks after treatment, and 3 months after treatment. Results · For sites with PD≥5 mm, PLI, PD, CAL, and the percentage of BOP positive sites significantly reduced for both groups at 6 weeks and 3 months after treatment compared with baseline (all P=0.000). For sites with 5 mm ≤ PD ≤ 6 mm, the CAL of the test group was significantly lower compared with the control group at 6 weeks after treatment (P=0.036). For sites with PD ≥ 7 mm, the PDs of the test group were significantly lower compared with the control group at 6 weeks and 3 months after treatment (P=0.002, P=0.039). The PD reduction between baseline and 6 weeks after treatment was greater in the test group compared with the control group (P=0.015). The CAL of the test group was lower compared with the control group at 6 weeks after treatment (P=0.011). The VAS of the test group was significantly lower than that of the control group (P=0.005). Conclusion · Adjunctive Er, Cr:YSGG laser application following subgingival scaling can achieve similar short-term clinical efficacy compared with traditional hand curettes. Er, Cr:YSGG laser may be beneficial particularly on the reduction of PD and regain of CAL in deep pockets on a short-term basis, which can make the patients more comfortable. Subgingival scaling with adjunctive Er, Cr:YSGG laser application can be an effective way for the non-surgical periodontal therapy.

Short-term clinical efficacy observation of adjunctive Er,Cr:YSGG laser application following subgingival scaling in patients with severe periodontitis / 上海交通大学学报（医学版）

Objective • To observe the short-term clinical efficacy of adjunctive Er,Cr:YSGG laser application following subgingival scaling in patients with severe periodontitis. Methods • In this parallel control design clinical trial, 46 patients with severe periodontitis were selected. Baseline examination was performed 2 weeks after supragingival scaling. Then the patients were randomly divided into the test group and the control group, with 23 cases in each group. After ultrasonic subgingival scaling, sites with probing depth (PD) ≥ 5 mm of patients in two groups received subgingival debridement with Er,Cr:YSGG laser and hand curettes, receptively. The changes in plaque index (PLI), PD, clinical attachment level (CAL), the percentage of bleeding on probing (BOP) positive sites, and the degree of subjective pain during treatment with visual analogue scale(VAS)were compared between two groups at baseline, 6 weeks after treatment, and 3 months after treatment. Results • For sites with PD ≥ 5 mm, PLI, PD, CAL, and the percentage of BOP positive sites significantly reduced for both groups at 6 weeks and 3 months after treatment compared with baseline (all P=0.000). For sites with 5 mm ≤ PD ≤ 6 mm, the CAL of the test group was significantly lower compared with the control group at 6 weeks after treatment (P=0.036). For sites with PD ≥ 7 mm, the PDs of the test group were significantly lower compared with the control group at 6 weeks and 3 months after treatment (P=0.002, P=0.039). The PD reduction between baseline and 6 weeks after treatment was greater in the test group compared with the control group (P=0.015). The CAL of the test group was lower compared with the control group at 6 weeks after treatment (P=0.011). The VAS of the test group was significantly lower than that of the control group (P=0.005). Conclusion • Adjunctive Er,Cr:YSGG laser application following subgingival scaling can achieve similar short-term clinical efficacy compared with traditional hand curettes. Er,Cr:YSGG laser may be beneficial particularly on the reduction of PD and regain of CAL in deep pockets on a short-term basis, which can make the patients more comfortable. Subgingival scaling with adjunctive Er,Cr:YSGG laser application can be an effective way for the non-surgical periodontal therapy.

Research progress on the bonding strength of primary teeth after Er, Cr: YSGG laser irradiation / 口腔疾病防治

@#With many advantages such as safety, effective cutting of enamel and dentin, Er, Cr: YSGG laser has gained more and more attention in recent years. After irradiation, the morphology, composition, and structure of tooth surface has changed, yet, the effect of these alterations to the bonding strength of the subsequent material is controversial. The paper has made a review from the following four aspects: Mechanism for tooth hard tissue cutting with Er, Cr: YSGG laser; The structure characteristics of primary teeth; The enamel bonding strength of primary teeth after Er, Cr: YSGG laser treatment; Safety, superiority and expectation for the application of Er, Cr: YSGG laser in primary teeth.

Effect of Laser Pre-Drilling on Insertion Torque of Orthodontic Miniscrews: A Preliminary Study

PURPOSE: To evaluate the effect of different-sized drill tips and laser irradiation times on the initial stability of orthodontic miniscrews placed in Er,Cr:YSGG-laser pre-drilled holes in an animal model. MATERIALS AND METHODS: Laser pre-drilled holes were made in dog mandibular bone with an Er,Cr:YSGG laser using irradiation times of 5, 7, 9, 11, and 13 seconds, and tip diameters of 0.4 and 0.6 mm. The maximum diameter and depth of the pre-drilled holes was measured with micro computed tomography. The maximum insertion torque was measured during placement the miniscrew. RESULT: Laser pre-drilled holes were conical shaped. The maximum diameter of pre-drilled holes increased with longer laser irradiation times (P>0.05) and larger tip diameters (P < 0.05). The depth of pre-drilled holes increased with longer laser irradiation times and larger tip diameters (P < 0.05). When the 0.4 mm tip, but not the 0.6 mm tip, was used, the insertion torque decreased significantly with longer laser irradiation times (P < 0.05). CONCLUSION: Tip diameter impacted insertion torque more than irradiation time. It takes at least 9 seconds using a 0.6 mm tip to create a 0.8 mm diameter and 1.0 mm depth hole in thick cortical bone.

The effect of Er, Cr∶YSGG laser irradiation on the acquired acid resistance of enamel and dentin in vitro / 实用口腔医学杂志

Objective:To investigate the acid resistance of tooth hard tissues irradiated by different power outputs of Er,Cr∶YSGG laser.Methods:Samples in laser groups were irradiated using Er,Cr∶ YSGG laser with the power outputs of 2.5,3.5 and 5 W for enamel and 2 W,3 W and 4 W for dentin,respectively.The calcium and phosphate ion dissolved was measured after decalcification in lactate buffer solution for 24 h.The atomic percentage of calcium and phosphate on the surface of samples was examined by X-ray energy dispersive spectroscopy and the morphological changes were investigated by SEM.Results:In all laser groups of enamel samples except 2.5 W group calcium and phosphate ion dissolved less than in control group and block group (P＜0.05).There's no statistic difference between different power groups.Compared with control group and block group,Ca/P ratio increased(P＜0.05).There's no statistic difference of the atomic percentage of Ca and P on the surface of dentin samples between each 2 groups.SEM observation showed that the surface of the laser irradiated samples was rouph,the space among enamel fibers was increased,the dentin around dentinal tuble orifice was protruded and looked like collar flange.Conclusion:Er,Cr∶YSGG laser irradiation with a range of power is effective in increasing acquired acid resistance of dental hard tissue.There was no relationship between laser power outputs and acid resistance.

Occluding effect of two kinds of Er laser on dentinal tubules:An in vitro study / 实用口腔医学杂志

Objective:To evaluate the occluding effect of 2 kinds of Er laser on dentinal tubules.Methods:27 dentine discs were prepared,etched with 0.5 mol/L EDTA and then divided into 3 groups(n =9).The samples in group A without treatment were used as the controls,in group B treated with Er:YAG laser irradiation and in group C treated with Er,Cr:YSGG laser irradiation.The occluding effect was examined by scanning electron microscopy (SEM).Results:Micrographs of SEMshowed obvious occluding effect in group B and C.The dentinal tubule exposure rates of group A,B and C were 33.61 0% ±7.545%,4.1 86% ±0.723% and 3.798% ± 0.843% respectively(among 3 groups,P 0.05).Conclusion:The 2 kinds of Er laser can block dentinal tu-bules.

Microshear bond strength according to dentin cleansing methods before recementation

PURPOSE: The aim of this study was to determine the efficiency of Erbium, Chromium: Yttrium-Scandium-Gallium-Garnet laser in different output powers for removing permanent resin cement residues and therefore its influence on microshear bond strength compared to other cleaning methods. MATERIALS AND METHODS: 90 extracted human molars were sectioned in 1 mm thickness. Resin cement was applied to surface of sliced teeth. After the removal of initial cement, 6 test groups were prepared by various dentin surface treatment methods as follows: no treatment (Group 1), ethylene diamine tetra acetic acid application (Group 2), Endosolv R application (Group 3), 1.25 W Erbium, Chromium:Yttrium-Scandium-Gallium-Garnet laser irradiation (Group 4), 2 W Erbium, Chromium:Yttrium-Scandium-Gallium-Garnet laser irradiation (Group 5) and 3.5 W Erbium, Chromium:Yttrium-Scandium-Gallium-Garnet laser irradiation (Group 6). The topography and morphology of the treated dentin surfaces were investigated by scanning electron microscopy (n=2 for each group). Following the repetitive cementation, microshear bond strength between dentin and cement (n=26 in per group) were measured with universal testing machine and the data were analyzed by Kruskal Wallis H Test with Bonferroni correction (P<.05). Fracture patterns were investigated by light microscope. RESULTS: Mean microshear bond strength +/- SD (MPa) for each group was 34.9 +/- 17.7, 32.1 +/- 15.8, 37.8 +/- 19.3, 31.3 +/- 12.7, 44.4 +/- 13.6, 40.2 +/- 13.2 respectively. Group 5 showed significantly difference from Group 1, Group 2 and Group 4. Also, Group 6 was found statistically different from Group 4. CONCLUSION: 2 W and 3.5 W Erbium, Chromium: Yttrium-Scandium-Gallium-Garnet laser application were found efficient in removing resin residues.

Morphological analysis of irradiated dentin by scanning electron microscope under anhydrous condition / 国际生物医学工程杂志

Objective To observe the surface morphology of dentin irradiated by Er,Cr∶YSGG laser under anhydrous conditions and discuss the possible clinical applications of the laser.Methods 11 freshly extracted specimens (approximately 1.5 mm thick) taken from the first premolars were selected.One was regarded as the control group without any treatment and the remaining ten were divided into 5 groups whose dentin surface was irradiated by Er,Cr∶ YSGG laser with different energy (1,2,3,4,6 W) under anhydrous condition.The specimens were routinely prepared for electron microscopic scanning observation.Results As the output power increased with Er,Cr∶YSGG laser irradiation,the dentin surface was observed of the constriction of tubular lumen,and part of the tubules closed.The dentin surfaces with 3 ～6 W laser irradiation were observed thermal injury alters such as micro crack and carbonization.Conclusion 1 ～2 W anhydrous Er,Cr:YSGG laser irradiation play a more ideal and safe constriction and sealing role to dentinal tubules,and the laser is expected to be used for the treatment of dentin hypersensitivity.

Shear bond strength of resin cement to an acid etched and a laser irradiated ceramic surface

PURPOSE: To evaluate the effects of hydrofluoric acid etching and Er,Cr:YSGG laser irradiation on the shear bond strength of resin cement to lithium disilicate ceramic. MATERIALS AND METHODS: Fifty-five ceramic blocks (5 mm x 5 mm x 2 mm) were fabricated and embedded in acrylic resin. Their surfaces were finished with 1000-grit silicon carbide paper. The blocks were assigned to five groups: 1) 9.5% hydrofluoric-acid etching for 60 s; 2-4), 1.5-, 2.5-, and 6-W Er,Cr:YSGG laser applications for 60 seconds, respectively; and 5) no treatment (control). One specimen from each group was examined using scanning electron microscopy. Ceramic primer (Rely X ceramic primer) and adhesive (Adper Single Bond) were applied to the ceramic surfaces, followed by resin cement to bond the composite cylinders, and light curing. Bonded specimens were stored in distilled water at 37degrees C for 24 hours. Shear bond strengths were determined by a universal testing machine at 1 mm/min crosshead speed. Data were analyzed using Kruskal-Wallis and Mann-Whitney U-tests (alpha=0.05). RESULTS: Adhesion was significantly stronger in Group 2 (3.88 +/- 1.94 MPa) and Group 3 (3.65 +/- 1.87 MPa) than in Control group (1.95 +/- 1.06 MPa), in which bonding values were lowest (P<.01). No significant difference was observed between Group 4 (3.59 +/- 1.19 MPa) and Control group. Shear bond strength was highest in Group 1 (8.42 +/- 1.86 MPa; P<.01). CONCLUSION: Er,Cr:YSGG laser irradiation at 1.5 and 2.5 W increased shear bond strengths between ceramic and resin cement compared with untreated ceramic surfaces. Irradiation at 6 W may not be an efficient ceramic surface treatment technique.

New innovative technology: waterlase in periodontics.

The Waterlase ™ is a revolutionary tool for dentists which is a unique combination of laser energy and water, a process called Hydro Photonics™, to perform many traditional dental procedures with less need of anesthesia. Since the Waterlase laser cuts hard and soft tissue without heat, vibration or pressure, the dentist may be able to perform the procedure without anesthesia. Also, using the Waterlase laser reduces bleeding, post-operative pain and swelling and the need for pain medication in many cases. It is extremely versatile. It can be used for a wide range of hard and soft tissue procedures including decay removal, cavity preparation, root canals, smile design, frenectomy, gingivectomy, gingivoplasty, curettage, vestibuloplasty, operculectomy, crown lengthening, flap surgery, removal of granulation tissue and bone surgical procedures and many others.

A comparison of bone bed preparation with laser and conventional drill on the relationship between implant stability quotient (ISQ) values and implant insertion variables

PURPOSE: The aim of this study was to investigate a comparison of implant bone bed preparation with Er,Cr:YSGG laser and conventional drills on the relationship between implant stability quotient (ISQ) values and implant insertion variables. MATERIALS AND METHODS: Forty implants were inserted into two different types of pig rib bone. One group was prepared with conventional drills and a total of 20 implants were inserted into type I and type II bone. The other group was prepared with a Er,Cr:YSGG laser and a total of 20 implants were inserted into type I and type II bone. ISQ, maximum insertion torque, angular momentum, and insertion torque energy values were measured. RESULTS: The mean values for variables were significantly higher in type I bone than in type II bone (P or = .05). The ISQ values were correlated with maximum insertion torque (P < .01, r = .731), total energy (P < .01, r = .696), and angular momentum (P < .01, r = .696). CONCLUSION: Within the limitations of this study, the effects of bone bed preparation with Er,Cr:YSGG laser on the relationship between implant stability quotient (ISQ) values and implant insertion variables were comparable to those of drilling.

The effect of Er,Cr:YSGG irradiation on microtensile bond strength of composite resin restoration / 대한치과보존학회지

The purpose of this study was to evaluate the effect of Er,Cr:YSGG laser irradiation with hypersensitivity mode on microtensile bond strength of composite resin. Twenty extracted permanent molars were randomly assigned to six groups, according to the irradiation of Er,Cr:YSGG laser, adhesive system (Optibond FL or Clearfil SE bond) and application time of etchant (15 sec or 20 sec). Then composite resin was build up on each conditioned surface. The restored teeth were stored in distilled water at room temperature for 24 h and twelve specimens for each group were prepared. All specimens were subjected to microtensile bond strength and the fracture modes were evaluated. Also, the prepared dentin surface and laser irradiated dentin surface were examined under SEM. The results were as follows: 1. The microtensile bond strength of laser irradiated group was lower than that of no laser irradiated group. 2. Regardless of laser irradiation, the microtensile bond strength of Optibond FL was higher than that of Clearfil SE bond. And the microtensile bond strength of 20 sec etching group was higher than that of 15 sec etching group when using Optibond FL. 3. The SEM image of laser irradiated dentin surface showed prominent peritubular dentin, opened dentinal tubules and no smear layer.

An experimental study on the effect of LASER on soft tissue healing