渗透树脂与前牙美学树脂颜色稳定性的比较研究

目的 通过分析不同树脂材料对饮料色素的着色效果,比较渗透树脂与前牙美学树脂颜色稳定性的差异。方法 选择3种前牙美学树脂（Filtek Z250、Filtek Z350 XT、Beautiful Flow Plus F00）及人工早期龋渗透树脂（Icon）处理样本各20例,不同树脂样本分别分为2组（每组10例）分别置于咖啡溶液及蒸馏水中浸泡1、2、3周。应用Crystaleye分光光度比色仪进行样本颜色分析。结果 人工早期龋渗透树脂处理表面的着色明显高于其他前牙美学树脂（P<0.05）。所有实验树脂及渗透树脂处理表面的着色均随时间延长而增加,但第1周的着色最为显著,明显高于第2周及第3周的着色（P<0.05）。结论 人工早期龋渗透树脂处理表面较前牙美学树脂更易发生颜色改变。     

牙本质玷污层特性对自粘接树脂水门汀粘接强度的影响

目的 评价牙本质表面玷污层的特性对自粘接型树脂水门汀粘接强度和耐久性的影响。方法 将48颗新鲜无龋的人第三恒磨牙暴露出牙本质表面,分别用标准粒径（105~125 μm）金刚砂车针（A组）和标准粒径+细粒径（25 μm）金刚砂车针进行研磨（B组）。研磨后的牙齿分别与Clearfil SA Cement（CSA）和Multilink Speed（MS）两种自粘接型复合树脂水门汀粘接,制成微拉伸试件,试件分别在水中存储24 h和2年,进行微拉伸强度测试,断裂后的试件使用体视显微镜观察粘接界面并记录断裂模式。采用扫描电子显微镜（SEM）观察研磨后的牙本质表面及牙本质-树脂粘接界面。结果 A组SEM观察到研磨后牙本质表面粗糙,玷污层较厚,牙本质小管口未完全栓塞;B组牙本质表面粗糙程度降低,牙本质小管口完全栓塞,玷污层变薄。CSA和MS的B组初期粘接强度显著低于A组（P<0.05）;CSA和MS的粘接强度在水储存2年后出现显著降低（P<0.05）,CSA的B组粘接强度显著低于A组（P<0.05）,而MS的A组与B组间的粘接强度无明显差异（P>0.05）。结论 牙本质表面玷污层特点及自粘接型树脂水门汀类型都会对粘接强度及耐久性产生影响。     

单端全瓷树脂粘接桥在修复个别前牙缺失中的应用

目的 探讨单端全瓷树脂粘接桥在修复个别前牙缺失中的临床效果。方法 选择20例个别前牙缺失患者进行单端全瓷树脂粘接桥修复,并进行2年随访,采用美国公共健康协会（APHA）制定的修复体临床评价标准进行临床疗效评价分析。结果 20例单端全瓷树脂粘接桥在修复完成后6个月,APHA的6项评价指标均达到A级;修复完成后1年,1例修复体周围龋为B级,其余均为A级;修复完成后2年,1例修复体周围龋为B级,1例修复体折断为B级,其余均为A级。结论 对于个别前牙缺失,单端全瓷树脂粘接桥是可供临床选择的修复方式之一。     

上颌单颗前牙位点保存后邻面牙槽嵴高度的早期变化

目的 探讨位点保存术对上颌单颗前牙拔除后邻面牙槽嵴高度早期变化的影响,为种植修复龈乳头美学效果提供参考依据。方法 选择需拔除上颌单颗前牙的30例患者为研究对象,将其随机分为试验组和对照组,每组15例。试验组在拔牙同时进行位点保存术（牙槽窝内植入 Bio-Oss骨粉,表面游离龈移植缝合固定）,对照组拔牙后未行其他处理。术后7 d及术后6个月,佩戴个性化数字化放射导板行锥形束CT检查,测量2组近远中邻面牙槽嵴及唇侧中央牙槽嵴高度的变化。结果 试验组近中、远中邻面及唇侧中点的牙槽嵴吸收高度分别为（0.358±0.151）mm、（0.322±0.180）mm、（0.826±0.307）mm,对照组近远中邻面及唇侧中点的牙槽嵴吸收高度分别为（0.653±0.260）mm、（0.667±0.274）mm、（1.510±0.625） mm。统计分析表明,试验组的牙槽嵴吸收高度小于对照组（P<0.05）,近中、远中邻面牙槽嵴的吸收高度均小于唇侧（P<0.05）。结论 位点保存术可以减少牙拔除后牙槽嵴高度的吸收,提高种植修复龈乳头美学效果。     

上颌单颗前牙位点保存后邻面牙槽嵴高度的早期变化

目的 探讨位点保存术对上颌单颗前牙拔除后邻面牙槽嵴高度早期变化的影响,为种植修复龈乳头美学效果提供参考依据。方法 选择需拔除上颌单颗前牙的30例患者为研究对象,将其随机分为试验组和对照组,每组15例。试验组在拔牙同时进行位点保存术（牙槽窝内植入 Bio-Oss骨粉,表面游离龈移植缝合固定）,对照组拔牙后未行其他处理。术后7 d及术后6个月,佩戴个性化数字化放射导板行锥形束CT检查,测量2组近远中邻面牙槽嵴及唇侧中央牙槽嵴高度的变化。结果 试验组近中、远中邻面及唇侧中点的牙槽嵴吸收高度分别为（0.358±0.151）mm、（0.322±0.180）mm、（0.826±0.307）mm,对照组近远中邻面及唇侧中点的牙槽嵴吸收高度分别为（0.653±0.260）mm、（0.667±0.274）mm、（1.510±0.625） mm。统计分析表明,试验组的牙槽嵴吸收高度小于对照组（P<0.05）,近中、远中邻面牙槽嵴的吸收高度均小于唇侧（P<0.05）。结论 位点保存术可以减少牙拔除后牙槽嵴高度的吸收,提高种植修复龈乳头美学效果。     

重庆市学龄前儿童乳牙龋状况及影响因素分析

目的 探讨重庆市3~5岁学龄前儿童乳牙患龋状况及相关影响因素,为学龄前儿童龋病的预防和干预提供相关资料。方法 参考第四次全国口腔健康流行病学调查,对重庆市4个区学龄前儿童进行抽样调查,同时对家长进行问卷调查。利用Epidata 3.1和SPSS 21.0软件进行结果录入和统计学分析。结果 共计1 350名学龄前儿童纳入调查分析,口腔检查相关数据显示乳牙龋好发牙位是上颌乳中切牙和下颌乳磨牙,乳牙患龋率为51.4%（694/1 350）,龋均为2.34,各年龄组间患龋率和龋均差异有统计学意义（P<0.01）,且二者随着年龄增长而上升（P<0.05）。除5岁组男、女龋均有统计学差异外（P<0.05）,其余患龋率和龋均在不同性别间差异均无统计学意义（P>0.05）。61.7%龋坏集中在36.1%个体口腔中。多因素Logistic回归分析显示年龄、家长的最高学历、甜饮料（包括碳酸饮料等）摄入频率、过去1年是否有牙痛或不适、是否看过牙、牙齿和口腔健康状况自评对乳牙患龋有重要影响（P<0.05）。结论 重庆地区3~5岁儿童超过半数患龋,多数龋齿集中发生在少数患儿口内。乳牙患龋与年龄、家长的最高学历、甜饮料（包括碳酸饮料等）摄入频率、过去1年是否有牙痛或不适、是否看过牙、牙齿和口腔健康状况自评有关。     

铸瓷高嵌体修复牙体严重缺损的年轻恒磨牙的效果分析

目的 评价铸瓷高嵌体修复严重缺损的年轻恒磨牙的临床效果。方法 选取牙体严重缺损的第一恒磨牙60颗,随机分为2组,分别进行树脂直接充填（树脂组）和铸瓷高嵌体修复（高嵌体组）。在修复后3、6、12、24个月检查两组患牙的修复体状态及咬合情况。按照改良USPHS/Ryge标准对修复体进行评价,使用T-Scan Ⅲ咬合分析系统进行咬合分析,记录牙龈状况和邻接关系恢复情况。结果 治疗后12个月,两组边缘适合性评分的差异有统计学意义,高嵌体组的A级多于树脂组（P<0.05）。治疗后12和24个月,两组表面光滑度评分的差异有统计学意义,高嵌体组的A级多于树脂组（P<0.05）。树脂组的患牙与对侧同名牙力百分比的差异均有统计学意义,患牙平均力百分比低于对侧同名牙（P<0.05）;而高嵌体组的患牙与对侧同名牙力百分比的差异均无统计学意义（P>0.05）。两组的牙龈状况和食物嵌塞情况均无明显差异（P>0.05）。结论 在本研究条件下,高嵌体组在修复体边缘适合性和表面光滑度方面,成功率较树脂组高,咬合力恢复也较树脂组更佳。在修复牙体严重缺损的年轻恒牙时,铸瓷高嵌体修复可作为推荐方案之一,有较好的修复效果。     

通用型粘接剂和树脂水门汀对氧化锆 剪切粘接强度的影响

目的 研究通用型粘接剂和树脂水门汀对氧化锆陶瓷剪切粘接强度和耐久性的影响。方法 氧化锆陶瓷烧结制作20 mm×10 mm×10 mm和10 mm×10 mm×10mm两种尺寸的试件,实验分为12组,将这2种试件分别采用不同的树脂水门汀（RelyX Ultimate树脂水门汀、Clearfil SAC自粘接树脂水门汀）和通用粘接剂（无粘接剂、Scotchbond通用粘接剂、Clearfil SE One粘接剂）在不同的储存条件（水浴、水浴+冷热循环）下进行粘接。测试剪切粘接强度,分析断裂形态。结果 水门汀（F=8.41,P<0.01）和粘接剂（F=30.34,P<0.01）对氧化锆剪切粘接强度的影响有统计学意义;储存条件对剪切粘接强度的影响无统计学意义（F=1.83,P=0.18）。RelyX Ultimate树脂水门汀、无粘接剂、水浴+冷热循环储存时的剪切粘接强度最低（14.02 MPa±6.86 MPa）,RelyX Ultimate树脂水门汀、Scotchbond通用粘接剂、水浴+冷热循环储存时的剪切粘接强度最高（54.12 MPa±8.37 MPa）。结论 通用型粘接剂可提高树脂水门汀对氧化锆的粘接耐久性。非自粘接的树脂水门汀如不使用通用型粘接剂则其粘接耐久性下降。     

通用型粘接剂和树脂水门汀对氧化锆剪切粘接强度的影响

目的 研究通用型粘接剂和树脂水门汀对氧化锆陶瓷剪切粘接强度和耐久性的影响。方法 氧化锆陶瓷烧结制作20 mm×10 mm×10 mm和10 mm×10 mm×10mm两种尺寸的试件,实验分为12组,将这2种试件分别采用不同的树脂水门汀（RelyX Ultimate树脂水门汀、Clearfil SAC自粘接树脂水门汀）和通用粘接剂（无粘接剂、Scotchbond通用粘接剂、Clearfil SE One粘接剂）在不同的储存条件（水浴、水浴+冷热循环）下进行粘接。测试剪切粘接强度,分析断裂形态。结果 水门汀（F=8.41,P<0.01）和粘接剂（F=30.34,P<0.01）对氧化锆剪切粘接强度的影响有统计学意义;储存条件对剪切粘接强度的影响无统计学意义（F=1.83,P=0.18）。RelyX Ultimate树脂水门汀、无粘接剂、水浴+冷热循环储存时的剪切粘接强度最低（14.02 MPa±6.86 MPa）,RelyX Ultimate树脂水门汀、Scotchbond通用粘接剂、水浴+冷热循环储存时的剪切粘接强度最高（54.12 MPa±8.37 MPa）。结论 通用型粘接剂可提高树脂水门汀对氧化锆的粘接耐久性。非自粘接的树脂水门汀如不使用通用型粘接剂则其粘接耐久性下降。     

17%乙二胺四乙酸冲洗液对牙本质粪肠球菌黏附的影响

目的 研究17%乙二胺四乙酸（EDTA）冲洗液对促进牙本质粪肠球菌黏附的影响。方法 将48例半劈样本及12例牙本质片样本随机分为3个实验组和1个对照组,实验组分别经17%EDTA处理1、3、5 min,对照组经生理盐水处理5 min,接种粪肠球菌后通过扫描电子显微镜、激光共聚焦电子显微镜（CLSM）、菌落形成单位及组织学方法进行细菌黏附量的评价。结果 除组织学革兰染色显示,1 min组与对照组、3 min组的细菌侵入深度无明显差异（P>0.05）外,其余结果显示,实验组细菌生物膜厚度、侵入牙本质小管深度（CLSM测量）及菌落计数均大于对照组,差异具有统计学意义（P<0.05）;3个实验组之间比较,差异也具有统计学意义（P< 0.05）。结论 17%EDTA冲洗液可促进粪肠球菌对牙本质的黏附,且黏附量随处理时间的延长而增加。     

10种复合树脂颜色稳定性与吸水溶解性研究

目的 评价10种光固化复合树脂在不同溶液中的颜色稳定性及吸水溶解性能。方法 10种光固化复合树脂分别为：BeautifilⅡ(B2)、Ceram. X One Universal (CXU)、Charisma (CS)、Charisma Diamond (CD)、Denfil (DF)、DX. Universal (DXU)、Filtek Z250 (Z250)、Filtek Z350 XT (Z350)、FS-1 (FS)、Magnafill Putty(MP)。每种树脂材料各制作20个试件,随机分为4组(n=5),分别浸入蒸馏水(对照组)、咖喱、咖啡和红酒28 d,分光光度计测量试件浸入前及浸入后1、7、14、21和28 d的色度值(CIE L^*a^*b^*),计算染色前后色差值。根据ISO 4049:2019标准,每种材料制作3个试件,测量材料的吸水性和溶解性。采用三因素方差分析评估树脂材料、染液、染色时间对染色前后色差值(ΔE)的影响,采用单因素方差分析比较不同材料的吸水值和溶解值变化。结果 随着染色时间增加,所有试...     

The effectiveness of four methods for stain removal from direct resin-based composite restorative materials

Background/purposeFew studies investigated the best method for removing stains from different types of resin-based composite restorations and compared them to the more recently introduced nanocomposites. This study compared the effect of four methods for stain removal from composite resins; finishing with Sof-lex disks, using pumice and brush, bleaching with 10% carbamide peroxide and 38% hydrogen peroxide.Materials and methodsTwenty disk specimens were prepared. Specimens were immersed in a staining solution for 3 weeks. The stained surfaces of five specimens from each RBC material were treated with one of the treatment procedures. Colorimetric measurements were taken using spectrophotometer prior to and after staining, and then repeated after surface treatments. Color difference values were calculated.ResultsOne-way ANOVA indicated significant differences in color change of the three composite resin materials following staining. Filtek Z250 showed the least susceptibility to discoloration followed by Renamel, Filtek Supreme was the material most prone to discoloration. Two-way ANOVA and Tukey’s Post Hoc showed that all stain removing procedures except polishing with pumice, were able to return Filtek Z250 to clinically acceptable color difference. While bleaching with 38% carbamide peroxide was not effective with Renamel. Only pumice and 10% carbamide peroxide were able to return Renamel to clinically acceptable color difference.ConclusionCompositions of resin-based composite resins play an important role in their susceptibility to stain and their amenability to stain removal procedures. Home bleaching showed good results for the three materials, while office bleach was the least effective.     

Influence of caries infiltrant contamination on shear bond strength of different adhesives to dentin

Objectives

To analyze whether the contamination with a caries infiltrant system impairs the adhesive performance of etch-and-rinse and self-etching adhesives on dentin.

Materials and methods

Dentin contamination with the caries infiltrant system (Icon, DMG) was simulated by applying either hydrochloric acid (15 % HCl, Icon Etch, 15 s), the resin infiltrant (Icon infiltrant, 4 min), or both prior to the application of the respective adhesives (each group n?=?10). In the control groups, the etch-and-rinse adhesive (Optibond FL, Kerr) and the self-etching adhesive (iBOND Self Etch, Hereaus) were applied without former contamination with the infiltrant system. Additionally, the adhesive performance of the resin infiltrant alone was tested. Shear bond strength of a nano-hybrid composite was analyzed after thermocycling (5,000×, 5–55°C) of the specimens and analyzed by ANOVA/Scheffé post hoc tests (p?<?0.05) and Weibull statistics. Failure mode was inspected under a stereomicroscope at?×?25 magnification.

Results

Contamination with the resin infiltrant alone did not impair shear bond strength, while contamination with hydrochloric acid or with hydrochloric acid and the resin infiltrant reduced shear bond strength (MPa) of the adhesives (Optibond FL: 20.5?±?3.6, iBOND Self Etch: 17.9?±?2.6) significantly. Hydrochloric acid contamination increased the number of adhesive failures. The adhesive performance of the caries infiltrant system alone was insufficient.

Conclusion

The contamination with the caries infiltrant system impaired the shear bond strength of conventional dental adhesives.

Clinical relevance

Contamination of the caries infiltrant system on dentin should be avoided due to the detrimental effect of hydrochloric acid etching.     

Shear bond strength of orthodontic resins after caries infiltrant preconditioning

Objective:To investigate the influence of caries infiltrant preconditioning on the shear bond strength of orthodontic resin cements on sound and demineralized enamel.Materials and Methods:Stainless-steel brackets were bonded to sound or artificially demineralized (14 d, acidic buffer, pH 5.0) bovine enamel specimens using a resin cement or a combination of caries infiltrant preconditioning (Icon, DMG) and the respective resin cement (light-curing composite: Heliosit Orthodontic, Transbond XT, using either Transbond XT Primer or Transbond Plus Self Etching Primer; light-curing resin-modified glass ionomer cement: Fuji Ortho; or self-curing composite: Concise Orthodontic Bonding System). Each group consisted of 15 specimens. Shear bond strength was evaluated after thermo-cycling (10,000×, 5°C to 55°C) at a crosshead speed of 1 mm/min, and data were statistically analyzed by analysis of variance, Mann-Whitney test, and Weibull statistics. Adhesive Remnant Index (ARI) scores and enamel fractures were determined at 25× magnification and were statistically analyzed by regression analyses (P < .05).Results:The caries infiltrant system significantly increased the shear bond strength of Transbond XT Primer, Transbond Plus Self Etching Primer, and Fuji Ortho in sound specimens, and of all resin cements except for the Concise Orthodontic Bonding System in demineralized enamel. Overall, caries infiltrant preconditioning decreased significantly the number of enamel fractures, but it did not affect ARI scores.Conclusion:Preconditioning of sound and demineralized enamel with the caries infiltrant system did not impair but rather increased the shear bond strength of most orthodontic resin cements while decreasing the risk of enamel fracture at debonding.     

大块复合树脂联合透明预成冠美学修复乳切牙的临床评价

目的探讨大块复合树脂联合透明预成冠用于患儿乳切牙美学修复的临床评价。方法预先设计临床前瞻性随机对照研究方法,选取入组患者90例(患牙123颗),随机数表法分为A、B、C三组,试验组A组为SF(SonicFill)大块复合树脂联合透明预成冠(30例,患牙41颗),对照组B组为Tetric N-Ceram Bulk Fill大块复合树脂联合透明预成冠(29例,患牙39颗)和C组为3M Z350 XT通用纳米树脂联合透明预成冠(31例,患牙43颗),采用视觉模拟评分法量表(VAS)和改良USPHS标准于术后12个月进行临床效果评价。结果术后12个月,A组的评价指标均优于2B、C组,差异均具有统计学意义,包括:边缘完整性(χ2=10.847,P=0.028),边缘台阶(χ2=7.799,P=0.020),边缘变色(χ2=10.391,P=0.034),表面状态(χ2=11.476,P=0.021);继发龋(χ2=10.447,P=0.034)。A组家长对整体轮廓(χ2=10.238,P=0.037)、形态质地(χ2=11.521,P=0.021)的满意度评价均优于B、C组,差异均具有统计学意义,3组家长对颜色满意程度评价无显著性差异(χ2=0.990,P=0.610)。结论 SonicFill大块复合树脂联合透明预成冠用于乳切牙美学修复短期效果较好,患儿家长满意度较高。     

Protection of sound enamel and artificial enamel lesions against demineralisation: Caries infiltrant versus adhesive

Objective

To compare the protective potential of a conventional adhesive, a caries infiltrant and a combination of both against acidic challenge in vitro.

Methods

One-hundred-and-fifty discs from bovine lower central incisors were fabricated. Seventy-five samples remained untreated, whereas the other half was subjected to a demineralisation process (14 days, acidic buffer, and pH 5) to create artificial enamel lesions. Specimens were then radioactively irradiated, and each 15 sound and demineralised specimens were treated with a caries infiltrant (Icon, DMG), an unfilled adhesive (Heliobond, IvoclarVivadent) or a combination of infiltrant and adhesive. Specimens treated with the adhesive followed by a flowable composite (TetricEvoFlow, IvoclarVivadent) served as positive control, while untreated specimens served as negative control. All samples were then subjected to lactic acid for 3 weeks at pH 4. Loss of apatite was determined using the radiochemical method of liquid scintillation. Data were statistically analysed by Kruskal–Wallis-test, one-way ANOVA and Scheffe's post hoc tests (p ≤ .05).

Results

In both sound enamel and artificial caries lesions, untreated specimens showed the highest rate of apatite loss, whereas enamel treated with the adhesive and the flowable composite showed almost complete protection surface against dissolution. The caries infiltrant, the adhesive and the combination of both were able to decrease enamel dissolution, but the adhesive and the combination of adhesive and infiltrant were more effective than the infiltrant alone.

Conclusion

Within the limitations of this in vitro study, the application of an adhesive (alone or in combination with the caries infiltrant) is more effective to protect enamel dissolution than the infiltrant alone.     

Diametral tensile strength of composite resins submitted to different activation techniques

The aim of this study was to evaluate the diametral tensile strength (DTS) of composite resins submitted to different curing techniques. Four composite resins were tested in this study: Targis (Ivoclar), Solidex (Shofu), Charisma (Heraeus-Kulzer) and Filtek Z250 (3M Espe). Sixty-four cylindrical specimens were prepared and divided into eight groups according to each polymerization technique (n = 8). The indirect composite resins (Targis and Solidex) were polymerized with their respective curing systems (Targis Power and EDG-lux); Charisma and Filtek Z250 were light-cured with conventional polymerization (halogen light) and additionally, with post-curing systems. Specimens were stored in artificial saliva at 37 degrees C for one week. DTS tests were performed in a Universal Testing Machine (0.5 mm/min). The data were statistically analyzed by ANOVA and Duncan tests. The results were (MPa): Z250/EDG-lux: 69.04 feminine; Z250/Targis Power: 68.57 feminine; Z250/conventional polymerization: 60.75b; Charisma/Targis Power: 52.34c; Charisma/conventional polymerization: 49.17c; Charisma/EDG-lux: 47.98c; Solidex: 36.62d; Targis: 32.86d. The results reveal that the post-cured Z250 composite resin showed the highest DTS means. Charisma composite presented no significant differences when activation techniques were compared. Direct composite resins presented higher DTS values than indirect resins.     

Clinical evaluation of flowable resins in non-carious cervical lesions: two-year results

This study evaluated the two-year clinical performance of one microhybrid composite and three different types of flowable resin materials in non-carious cervical lesions. A total of 252 noncarious cervical lesions were restored in 37 patients (12 male, 25 female) with Admira Flow, Dyract Flow, Filtek Flow and Filtek Z250, according to manufacturers' instructions. All the restorations were placed by one operator, and two other examiners evaluated the restorations clinically within one week after placement and after 6, 12, 18 and 24 months, using modified USPHS criteria. At the end of 24 months, 172 restorations were evaluated in 26 patients, with a recall rate of 68%. Statistical analysis was completed using the Pearson Chi-square and Fisher-Freeman-Halton tests (p < 0.05). Additionally, survival rates were analyzed with the Kaplan-Meier estimator and the Log-Rank test (p < 0.05). The Log-Rank test indicated statistically significant differences between the survival rates of Dyract Flow/Admira Flow and Dyract Flow/Filtek Z250 (p < 0.05). While there was a statistically significant difference between Dyract Flow and the other materials for color match at 12 and 18 months, no significant difference was observed among all of the materials tested at 24 months. Significant differences were revealed between Filtek Z250 and the other materials for marginal adaptation at 18 and 24 months (p < 0.05). With respect to marginal discoloration, secondary caries, surface texture and anatomic form, no significant differences were found between the resin materials (p > 0.05). It was concluded that different types of resin materials demonstrated acceptable clinical performance in non-carious cervical lesions, except for the retention rates of the Dyract Flow restorations.     

Micro-hardness and mineral loss of enamel lesions after infiltration with various resins: Influence of infiltrant composition and application frequency in vitro

Objectives

The aim of this in vitro study was to evaluate the influence of infiltrant composition and application frequency on micro-hardness and lesion progression after resin infiltration of artificial enamel lesions.

Methods

In each of 100 bovine enamel samples, three artificial caries lesions were created (pH = 4.95, 50 days). After etching two of the lesions (37% phosphoric acid) specimens were randomly allocated to five infiltrants (four experimental infiltrants with different monomer and solvent compositions and penetration coefficients, and one commercial infiltrant [Icon, DMG]). Lesions were then infiltrated and light-cured, and infiltration repeated afterwards for one of the lesions. Infiltrated samples were cut into halves, with one half being demineralised for further 50 days. Micro-hardness (VHN) and integrated mineral loss (ΔZ) were evaluated at baseline and after second demineralisation. Repeated measures ANOVA and paired t-tests were used to analyse influence of material composition and application frequency on micro-hardness and lesion progression (integrated mineral loss difference ΔΔZ).

Results

Resin infiltration significantly increased micro-hardness and reduced lesion progression compared to untreated artificial lesions (p < 0.05, t-test). Neither micro-hardness nor lesion progression were significantly influenced by material composition (p > 0.05, ANOVA). In contrast, twice application resulted in significantly increased micro-hardness and demineralisation resistance of infiltrated lesions (p < 0.05, ANOVA).

Conclusion

Resin infiltration significantly improves micro-hardness and demineralisation resistance of enamel lesions; these effects are significantly enhanced if resins are applied twice. Experimental resins did not outperform the commercial infiltrant.

Clinical significance

This in vitro study demonstrated that resin infiltration significantly increases both micro-hardness and demineralisation resistance of enamel caries lesions. Twice application of the infiltrant seems to increase these effects. In contrast, the composition of the infiltrant had no significant influence on investigated parameters.