Er∶YAG激光光子增强的光声流效应技术清理根管玷污层效果的体外研究

目的　观察不同Er∶YAG激光技术对根管内壁玷污层的清理能力,探究光子增强的光声流效应（shock wave enhanced emission photoacoustic streaming,SWEEPS）技术对根管内壁玷污层的清理效果。方法　示波器精确测定Er∶YAG激光不同工作模式的脉冲波形。收集人离体第三磨牙（85颗）,使用机用ProTaper Universal镍钛锉进行根管预备至30号（锥度0.09）,建立玷污层模型,并使用5.25%次氯酸钠在预备过程中进行冲洗。分别应用Er∶YAG激光SWEEPS技术与光子诱导的光声流效应（photon-induced photoacoustic streaming,PIPS）技术激活17%EDTA,清理离体牙根管内壁玷污层30 s和60 s。将激光激活荡洗后的样本沿牙体组织长轴纵向劈开,扫描电镜分别观察距离根尖孔1、4及8 mm的根管内表面并进行评分。红外热像仪记录两种不同Er∶YAG激光技术激活荡洗时离体牙外表面的温度变化。结果　SWEEPS技术是一种双脉冲Er∶YAG激光工作模式,该技术对距离根尖孔4 mm及1 mm的玷污层清理效果优于PIPS技术 （P < 0.05）。红外热像仪检测发现两种Er∶YAG激光技术在激活荡洗过程中对牙周膜的热负效应差异无统计学意义 （P > 0.05）。结论　与PIPS技术相比,应用Er∶YAG激光SWEEPS技术可对根中段及根尖段玷污层有更好的清理效果,同时不增加对牙周膜的热负效应。     

Er:YAG激光桩道荡洗技术对纤维桩微渗漏的影响

目的:研究Er:YAG激光桩道荡洗技术对纤维桩微渗漏的影响.方法:选取大小形状相似的30颗单根管离体上前牙,经常规根管治疗后,根管上段2/3行桩道预备.按照荡洗技术随机平均分成3组:生理盐水组、2.5％次氯酸钠溶液组、Er:YAG激光联合2.5％次氯酸钠溶液组.纸尖干燥桩道并完成纤维桩粘接.截取离体牙釉牙骨质界至下方6 mm牙体作为检测试件,采用葡萄糖氧化酶-过氧化物酶法测量其微渗漏情况.结果:生理盐水荡洗组的微渗漏为(0.941±0.096)mmol/L,2.5％次氯酸钠溶液荡洗组的微渗漏为(0.911±0.075)mmol/L,Er:YAG激光联合2.5％次氯酸钠荡洗组的微渗漏为(0.889±0.102)mmol/L.3种荡洗技术间的微渗漏程度比较差异有统计学意义(P<0.05).结论:Er:YAG激光辅助荡洗桩道能够减少纤维桩微渗漏.     

不同参数激光处理根管对纤维桩粘结强度影响的实验研究

目的:研究不同参数Er:YAG激光处理根管壁牙本质对纤维桩粘结强度的影响,为激光临床应用提供参考。方法:收集60颗人类上颌中切牙,根据不同处理方法随机分为5组;空白对照组;3 W-50 μs Er:YAG激光组;3 W-100 μs Er:YAG 激光组;4.5 W-50 μs Er:YAG激光组;4.5 W-100 μs Er:YAG激光组,每组12颗。离体牙根管预备,充填,桩道预备后,Bisco树脂加强型纤维桩通过RelyX^TM Unicem粘结树脂水门汀粘固于根管内。流水状态下慢速锯将纤维桩外周平行片切,再垂直粘结面片于试件1 mm、4 mm、7 mm处切成三段1.0 mm×1.0 mm的长方形柱状试件,进行微拉伸强度测试。不同根管处理方法与牙根不同区域微拉伸强度均数采用两因素方差分析(α=0.05)。电镜下进行断裂类型分析,组件不同类型断裂率采用χ²检验(α=0.05)。 结果:3 W10-100 μs Er:YAG组拉伸强度值最高(5.55±0.97) MPa,与对照组(4.06±1.22) MPa相比较差异有显著性(P＜0.05) 。根管上部和中部粘结强度高于根管下部,差异有显著性(P＜0.05)。结论:Er:YAG激光处理牙本质表面对其与纤维桩粘结强度的影响与激光功率大小和脉冲持续时间有关,3 W-100 μs Er:YAG激光处理表面可以显著增强纤维桩与根管牙本质的粘结强度。     

Er:YAG激光光子激活光声流技术对根管壁牙本质失水状况及牙根抗压强度的影响

目的探讨PIPS-Er:YAG激光技术(光子激活光声流)治疗后根管壁牙本质失水状况及对牙根抗压强度的影响。方法选取2018年7—9月南京市口腔医院口腔颌面外科门诊拔除的120颗健康正畸减数牙(单根牙)进行离体牙实验,按随机数字表法将其均分为A组(PIPS-Er:YAG激光冲洗组)、B组(注射器冲洗组)、C组(超声荡洗组)和D组(空白对照组,未治疗),比较治疗后各组根管壁牙本质失水状况和治疗前后牙根抗压强度的差异。结果 1) A~D组内各标本根管上、中、下段根管壁牙本质含水量依次递增,但差异无统计学意义(P>0.05);根管壁上段:A、C组低于B、D组(P<0.05),A组略低于C组(P>0.05),B组低于D组(P<0.05);根管壁中段:A组低于B~D组(P<0.05),A组略低于C组(P>0.05),B组低于D组(P<0.05);根管壁下段:A组低于B~D组(P<0.05)、A组略低于C组(P>0.05),B组低于D组(P<0.05)。2) A、B、C组与D组间的抗压强度差异无统计学意义(P>0.05)。结论使用Er:YAG激光PIPS技术能降低根管壁牙本质的含水量,且不会降低牙根的抗压强度,有良好的临床应用前景。     

不同根管动能冲洗方式冲洗效果的研究

目的 比较被动超声冲洗技术、EDDY声波冲洗技术和Er∶YAG激光冲击波增强型发射光声流（shock-wave enhanced emission photo acoustic streaming,SWEEPS）模式冲洗技术清除根管内粪肠球菌的效果。方法 本研究于2023年2—6月在上海交通大学医学院附属第九人民医院牙体牙髓科及口腔微生态与系统性疾病实验室进行。构建3D下颌第一前磨牙粪肠球菌根管感染牙齿模型15颗,将模型分为超声组、EDDY组、SWEEPS-Er∶YAG组,每组5颗。应用上述相应冲洗方式对3组牙齿模型进行根管冲洗,每颗牙齿模型冲洗3次,冲洗前及每次冲洗后用无菌纸尖采集主根管和侧支根管样本,用平板细菌计数法对样本进行检测分析。结果 SWEEPS-Er∶YAG组主根管在冲洗30、60 s后和侧支根管在冲洗60、90 s后菌落数均显著小于超声组和EDDY组,差异均有统计学意义（均P <0.05）;SWEEPS-Er∶YAG组主根管在冲洗30、60 s后和侧支根管在冲洗30、60、90 s后细菌载量的减少率均高于超声组和EDDY组,差异均有统计学意义（均P <0.0...     

Er∶YAG激光SWEEPS双脉冲模式激活荡洗在自由水域中的气泡动力学观测

目的:探究Er∶YAG激光光子增强的光声流(SWEEPS)技术在不同脉冲间隔参数条件下的蒸汽气泡动力学效应。方法:Er∶YAG激光手具连接工作尖放置于自由水域模型中,设置SWEEPS模式,150～600μs脉冲间隔激活。高速摄像机(200 000 Hz)摄录Er∶YAG激光激活荡洗引起空穴效应的过程,matlab逐帧分析蒸汽气泡间的相互作用关系,及蒸汽气泡消失时刻气泡残余与激光工作尖之间的距离。实验数据经SPSS 19.0统计软件进行统计分析。结果:在自由水域中,Er∶YAG激光SWEEPS模式下,脉冲间隔设置的改变会引起两次脉冲激发的蒸汽气泡形成不同的相互作用关系,包括双气泡融合、双气泡撞击及双气泡脱离。其中,脉冲间隔设置为360～440μs时,双气泡撞击现象会使蒸汽气泡消失时气泡残余与激光工作尖之间达到最远距离。结论:在自由水域中,Er∶YAG激光双脉冲SWEEPS模式在不同的脉冲间隔设置下引起双气泡间形成不同的作用关系,该现象可能可以增强Er∶YAG激光空穴效应,强化激光激活荡洗的临床应用效果。     

Er:YAG激光对弯曲根管内粪肠球菌灭菌效果的体外研究

目的:探究Er:YAG激光PIPS、SWEEPS与传统冲洗方法在多根牙的直根管及弯曲根管内的灭菌效果差异.方法:分别选取直根管和弯曲根管多根牙建立粪肠球菌感染模型.将离体牙随机分为8组,每组15例,做以下处理:A(PIPS+直根管);B(PIPS+弯曲根管);C(SWEEPS+直根管);D(SWEEPS+弯曲根管);E(PUI+直根管);F(PUI+弯曲根管);G(CI+直根管);H(CI+弯曲根管),选取同批次离体牙做空白对照.处理后提取培养细菌,24 h后菌落计数,并进行扫描电镜和激光共聚焦观察.结果:各组灭菌效果:直根管:PIPS/SWEEPS>PUI>CI;弯曲根管组:SWEEPS>PIPS/PUI>CI;SWEEPS组在根管在根尖部能达到更高的灭菌深度及玷污层去除效果.结论:与传统根管冲洗方法相比,Er:YAG激光PIPS、SWEEPS对弯曲根管内细菌及玷污层去除效果显著提高,且SWEEPS优于PIPS.     

利用SEM观察Er:YAG激光活化冲洗对根管内玷污层清理效果的体外研究

目的:通过扫描电子显微镜(scanning electron microscope, SEM)观察3%次氯酸钠联合Er:YAG激光活化冲洗对根管内玷污层的清除效果。方法:选择40颗离体前磨牙，采用机动ProTaper镍钛锉进行根管预备至F3后根据处理方案的不同随机分为4组(n=10)。A组：5 mL 0.9%生理盐水处理60 s; B组：5 mL 3%次氯酸钠溶液处理60 s; C组：5 mL 17%EDTA溶液处理60 s; D组：5 mL 3%次氯酸钠溶液+Er:YAG激光活化冲洗60 s。用SEM观察根管内玷污层的去除情况并进行评分。结果:D组玷污层清除效果优于A、B、C组，差异具有统计学意义(P<0.05);同组内根管内玷污层的清除情况为根上1/3>根中1/3>根尖1/3;D组在根尖1/3玷污层的去除效果显著优于A、B、C组；差异均有统计学意义(P<0.05)。结论:3%次氯酸钠联合Er:YAG激光活化冲洗可更有效去除根管内玷污层，相较于传统化学冲洗方法，在清理根尖1/3处玷污层时更具优势。     

奥敏清牙齿脱敏剂联合Er:YAG激光治疗青少年牙本质敏感症的临床观察及实验研究

目的:对奥敏清牙齿脱敏剂联合Er:YAG激光治疗青少年牙本质敏感症的疗效进行研究。方法:78例(共163颗患牙)青少年牙本质敏感症患者随机分为奥敏清组(n=54)、激光组(n=55)和联合组(n=54),奥敏清组患者给予单一奥敏清牙齿脱敏剂涂布治疗,激光组患者给予单一的Er:YAG激光照射治疗,联合组患者在Er:YAG激光照射后再涂布奥敏清牙齿脱敏剂治疗,比较治疗前、治疗即刻和治疗后1周、1月、3月、6月VAS值、总有效率。另将20颗新鲜离体牙随机分为4组,分别用生理盐水、奥敏清牙齿脱敏剂、Er:YAG激光及奥敏清联合Er:YAG激光处理,扫描电镜观察各模型样本形态。 结果:联合组在治疗即刻及治疗后各时间点的VAS值均显著低于奥敏清组和激光组(P<0.05);总有效率均显著高于奥敏清组和激光组(P<0.05);奥敏清组和激光组在治疗即刻、治疗后1周、1月、3月时的总有效率差异无统计学意义,但激光组在治疗后6月的总有效率却显著高于奥敏清组(P<0.05)。扫描电镜结果显示奥敏清、Er:YAG激光及奥敏清联合Er :YAG激光处理均可封闭牙本质小管,且奥敏清联合Er:YAG激光的封闭效果最佳。结论:奥敏清牙齿脱敏剂联合Er:YAG激光治疗青少年牙本质敏感症具有较好的临床效果。     

桩道牙本质壁的不同处理对纤维桩粘接强度的影响

目的：比较使用自粘接型树脂水门汀粘接纤维桩时,经3种不同方法处理桩道牙本质壁后对纤维桩粘接强度的影响。方法：收集30颗因正畸需拔除的健康下颌单根管前磨牙进行截冠、常规根管治疗、桩道预备后随机分为3组,每组10颗;使用不同方法对桩道牙本质壁进行处理：Ⅰ组(对照组)：手动注射器冲洗;Ⅱ组(超声组)：超声冲洗;Ⅲ组(激光组)： Er： YAG激光冲洗。使用自粘接桩核树脂水门汀将纤维桩粘接完毕后切片进行薄片推出实验。采用双因素方差分析检验桩道牙本质壁的不同处理方法及桩道的不同深度(根颈部,根中部,根尖部)对纤维桩粘接强度的影响,并用万能显微镜观察试件的破坏方式,对结果进行Chi-Square检验。设定检验标准α=0.05。结果：各组粘接强度差异有统计学意义,Ⅱ组和Ⅲ组的粘接强度显著高于Ⅰ组(P<0.05),桩道不同深度纤维桩的粘接强度差异无统计学意义(P=0.082);各组破坏方式以混合破坏为主,但Ⅱ组和Ⅲ组中桩道牙本质壁—树脂水门汀破坏比例较Ⅰ组明显降低。结论：使用自粘接型树脂水门汀时,经超声或激光处理预备后的桩道可显著提高纤维桩的粘接强度。桩道深度对纤维桩的粘接强度无影响。     

Effect of Er:YAG laser on removal of fibre posts from root canal

The aim of this study was to evaluate the efficiency of Er:YAG laser in translucent fibre post removal. 60 human single-rooted anterior teeth were divided into three groups (n = 20) according to post diameters (Exacto1-E1, Exacto2-E2, Exacto3-E3) and subdivided according to laser application. Fibre posts were cemented to endodontically treated teeth, and the specimens were sliced with a thickness of 1.0 ± 0.2 mm. Er:YAG laser was applied and the push out bond strength test was performed. Two-way analysis of variance was used to perform the statistical analysis. Push out bond strengths at apical area were significantly lower in all test groups (p < 0.05). Laser application caused increase in all radicular thirds, but it was significant for E1 and E3 groups. Laser application to the post-dentine interface enhances the connection between post and dentine.     

Efficacy of Photon-induced Photoacoustic Streaming in the Reduction of Enterococcus faecalis within the Root Canal: Different Settings and Different Sodium Hypochlorite Concentrations

Introduction

The purpose of this study was to determine the effectiveness of laser-activated irrigation by photon-induced photoacoustic streaming (PIPS) in the reduction of Enterococcus faecalis in root canal disinfection, varying laser energy output, and sodium hypochlorite (NaOCl) concentration. For effective removal of the smear layer, the sequence and resting time of the final irrigation steps were modified compared with the standard PIPS protocol.

Bond strength of self-adhesive resin cement to root dentin. Comparison of photon-initiated photoacoustic streaming technique with needle and ultrasonic irrigation

Abstract

Objective. The aim of this study was to investigate the effects of photon-initiated photoacoustic streaming (PIPS) with various irrigating solutions on the bond strength of a self-adhesive resin cement to root dentin. Materials and methods. Seventy-two mandibular premolar roots were divided into six groups after post space preparation and treated with a needle irrigation with distilled water and NaOCl, ultrasonic irrigation with NaOCl, PIPS with NaOCl, PIPS with EDTA and PIPS with distilled water at 0.3 W, 15 Hz and 20 mJ per pulse for 60 s. Fiber posts were cemented with a newly marketed, self-adhesive resin cement. The data obtained from the push-out tests were analyzed using analysis of variance (ANOVA) and LSD post-hoc tests (p = 0.05). Results. PIPS with distilled water resulted in higher push-out values than those of needle (with both distilled water and NaOCl) and ultrasonic irrigation (p < 0.05). Conclusions. The use of PIPS may provide higher bond strength of self-adhesive resin cement to root dentin than needle and ultrasonic irrigation techniques.     

Disinfection efficacy of photon-induced photoacoustic streaming on root canals infected with Enterococcus faecalis: An ex vivo study

BackgroundIn 2010, one of the authors proposed that lasers could be used to enhance the decontaminating action of sodium hypochlorite (NaOCl). The authors conducted a study to compare the disinfection efficacy of laser-activated irrigation (LAI) by using a photon-induced photoacoustic streaming (PIPS) tip with conventional irrigation and specifically LAI's ability to remove bacterial film formed on root canal walls.MethodsThe authors shaped 26 human anterior teeth to a master apical file size of International Organization for Standardization 25/06 (size 25 tip and size .06 taper) and then sterilized the teeth, infected them with Enterococcus faecalis and incubated them for four weeks. The authors used two irrigation protocols. Group A received two cycles of 30 seconds each of 5 percent NaOCl laser activation and one cycle of 30 seconds with laser activation involving the use of 17 percent ethylenediaminetetraacetic acid (EDTA). The erbium:yttrium-aluminum-garnet (Er:YAG) laser's settings were 20 millijoules, 15 hertz, 50-microsecond pulse duration, and it had a 600-micrometer PIPS tip. Group B received two cycles of 30 seconds each of 5 percent NaOCl and 17 percent EDTA irrigation alone, delivered via a syringe with a 25-gauge needle.ResultsThe authors found that group A had significantly better disinfection compared with group B (P < .05). The results of cultures obtained after 48 hours showed that disinfection was maintained better in group A compared with group B (P < .0001). Scanning electron microscopic images showed absence of bacterial biofilm remaining after LAI using PIPS.ConclusionsEr:YAG laser activation of 5 percent NaOCl and 17 percent EDTA was more effective than conventional irrigation for eradicating E. faecalis and preventing new bacterial growth ex vivo. Additional clinical studies are needed to clarify the effect on endodontic treatment outcomes.Practical ImplicationsPIPS appears to be effective in enhancing the effect of the irrigants commonly used in endodontics.     

Evaluation of surface roughness and bond strength of quartz fiber posts after various pre-treatments

Purpose. Debonding at the post-adhesive interface is a major problem for quartz fiber posts. The objective of this study was to evaluate surface roughness and bond strength of quartz fiber posts after various surface treatments. Materials and methods. Sixty-six quartz fiber posts were randomly divided into six experimental groups (n = 11) including group C, untreated (control); group SB, sandblasted; group SC, silica coated; group HF, hydrofluoric acid-etched; group N, Nd:YAG laser irradiated; group E, Er:YAG laser irradiated. Surface roughness of the posts was measured before and after pre-treatment. They were then bonded to resin cement and tensile bond strength was determined in a universal testing machine. Furthermore, two-way ANOVA and post hoc comparison tests (α = 0.05) were performed on all data. Results. The highest mean force value was observed in group SB and followed by group E. Tukey’s HSD test showed that there was no statistical difference between group SB and group E (p = 0.673). The highest mean roughness value was observed in group SB and a significant difference was found between group SB and all other groups (p < 0.001). This study reveals that sandblasting and Er:YAG laser irradiation provided a significant increase in bond strength between quartz fiber posts and resin cement. Conclusions. Sandblasting or Er:YAG laser-irradiation of the surface of the quartz fiber post before cementation is recommended for increasing retention.     

Potential applications of Erbium:YAG laser in periodontics

OBJECTIVES: Since lasers were introduced for the treatment of oral diseases, there has been considerable advancement in technology. As a result, numerous laser systems are currently available for oral use. Neodymium:Yttrium-Aluminum:Garnet (Nd:YAG), carbon dioxide (CO(2)) laser and the semiconductor Diode lasers have already been approved by the US Food and Drug Administration for soft tissue treatment in oral cavity. The Erbium:YAG (Er:YAG) laser was approved in 1997 for hard tissue treatment in dentistry and recent studies have reported positive results. This suggests that the Er:YAG laser system is a promising apparatus, which will be able to revolutionize and improve dental practice, in particular periodontal treatment. In this mini-review, we would like to describe the positive characteristics of the Er:YAG laser which indicate its potential as a new treatment modality in periodontics. MATERIALS AND METHODS: Recent findings are summarized briefly to evaluate the potential of the Er:YAG laser for clinical application in periodontics. RESULTS: The Er:YAG laser possesses suitable characteristics for oral soft and hard tissue ablation. Recently, it has been applied for effective elimination of granulation tissue, gingival melanin pigmentation and gingival discoloration. Contouring and cutting of bone with minimal damage and even or faster healing can also be performed with this laser. In addition, irradiation with the Er:YAG laser has a bactericidal effect with reduction of lipopolysaccharide, high ability of plaque and calculus removal, with the effect limited to a very thin layer of the surface and is effective for implant maintenance. CONCLUSION: The Er:YAG laser seems to be an effective tool for periodontal therapy, however, further clinical and basic investigations are required to confirm its clinical application.     

The effect of the application of gaseous ozone and ND:YAG laser on glass‐fibre post bond strength

The aim of this study was to investigate the effects of the application of gaseous ozone and Nd:YAG laser on glass‐fibre post bond strength. Forty‐two madibular premolar roots were cut, endodontically instrumented and irrigated with 2.5% NaOCl. Post spaces were prepared and roots were divided into three groups (n = 14). The antimicrobial pretreatment was conducted as follows: gaseous ozone, Nd:YAG laser and control (no additional disinfection methods). Scanning electron microscope analysis was made for each group (n = 2). A resin cement was used for luting the posts. For push‐out test, each root was cut horizontally (two cervical, two middle and two apical). Statistical analyses were performed with one‐way anova (α = 0.05). Fracture types were observed. There was no statistically significant difference between the groups (P > 0.05). There were statistically significant differences in cervical and apical segments of laser and control groups (P < 0.05). The disinfection of the post spaces with Nd:YAG laser and ozone had no adverse effects on bond strength of glass‐fibre post.     

Effect of different laser-assisted irrigation activation techniques on apical debris extrusion

Abstract

Objective: The aim of this study was to compare apical debris extrusion when neodymium-doped yttrium aluminium garnet (Nd:YAG) lasers, erbium-doped yttrium aluminium garnet (Er:YAG) or photon-induced photoacoustic streaming (PIPS) are used for irrigation activation.

Materials and methods: A total of 60 extracted human mandibular premolar teeth have similar dimensions were included and the samples were split into four groups according to the irrigation technique (n?=?15): conventional needle irrigation, PIPS, Er:YAG and Nd:YAG. ProTaper Universal system up to F4 was used for root canal instrumentation. Bidistilled water was used as an irrigation solution during instrumentation and irrigation activation. Apically extruded debris was collected into preweighed Eppendorf tubes during instrumentation and irrigation activation procedures. The tubes were then kept in an incubator at 70?°C for 5?days. The initial weight of the tube was subtracted from the final weight and the result was recorded as the weight of dry extruded debris. The data were evaluated statistically using a one-way ANOVA test followed by least significant difference post hoc test (p?<?.05).

Results: Conventional needle irrigation caused significantly less debris extrusion than laser-assisted irrigation activation groups (p?<?.05). Laser-assisted irrigation activation groups caused statistically similar debris extrusion (p?>?.05).

Conclusion: Laser-assisted irrigation activation techniques caused more debris extrusion when compared to conventional needle irrigation.