Flow characteristics and sealing ability of fissure sealants

This study evaluated the relationship between fissure sealant viscosity, leakage prevention and the incidence of void formation of five commercially available pit-and-fissure sealants. Seventy-two intact, caries free human pre-molars and molars were divided into six test groups of 12 teeth each. All teeth were cleaned with a flour of pumice prophylaxis followed by etching for 60 seconds with 37% H3PO4, rinsing for 30 seconds and drying with oil-free air. Five commercial, light-cured fissure sealants and an unfilled version of one sealant were applied following manufacturers' instructions. Teeth were thermal cycled for 5000 cycles from 5-50 degrees C with a one-minute dwell time at each temperature. Silver nitrate staining followed by mesiodistal sectioning was performed. Leakage and void formation were evaluated at X50 optical magnification. Viscosity was assessed by syringing the fissure sealants into short pipettes, allowing free flow for 30 seconds and then light curing for one minute. The length of unfilled capillary was measured with a Vernier gauge. All experimental data was subjected to a one-way ANOVA, and where differences were detected, they were identified by a post hoc Tukey hsd test at a priori alpha = 0.05. Based on the conditions of the study, viscosity and flow characteristics had no effect on sealing ability or void formation.     

The economic evaluation of pit and fissure sealants

This paper reviews the literature relating to the economic evaluation of sealants. Economic issues are commonly cited for lack of sealant utilization, although there are no adequate economic analyses on which to base this belief. The design of much of the existing economic literature regarding sealants is inappropriate, for example many analyses do not consider the advantages of a sound tooth in the calculation of budget. In general the recent literature supports the efficiency and the effectiveness of sealants. However, there is a need for well designed studies, examining modern materials and populations with current caries prevalence. In particular there is a need for well conducted cost–benefit analyses and cost-utility analyses, which should encompass discounting for time and sensitivity analyses. Results from such research would assist clinicians and policy makers alike, in decisions regarding the provision of care with regard to sealant provision at the individual and community level.     

Influence of salivary contamination on marginal microleakage of pit and fissure sealants

PURPOSE: To assess quantitatively the influence of salivary contamination in vitro on marginal microleakage of pit and fissure sealants. METHODS: Forty-eight sound human third molars were selected and assigned to three groups: 1) Fluroshield (F), 2) Single Bond + Fluroshield (SBF) and 3) Ketac-fil (KF). Each group was divided into two subgroups: control (C) and with salivary contamination (SC). The occlusal surfaces were etched with 40% polyacrylic acid for 10 seconds or 37% phosphoric acid for 30 seconds, for either glass-ionomer or resin-based sealants, respectively. Specimens were contaminated with 0.25 mL of fresh human saliva for 20 seconds and dried afterwards. The sealants were placed and samples were thermocycled, immersed in a 0.2% Rhodamine B solution for 24 hours, embedded in acrylic resin and serially sectioned. The sections were viewed under an optical microscope connected to a computer and a video camera, and the images obtained were digitized. The extent of dye penetration along buccal and lingual slopes was measured in millimeters, using specific computer software, and converted into percentage, according to the fissures extension. RESULTS: The microleakage means (%) were: F/C:0 (+/- 0); F/SC: 31.71 (+/- 31.69); SBF/C: 0 (+/- 0); SBF/SC: 0 (+/- 0); KF/C: 0.98 (+/- 2.79) and KF/SC: 11.82 (+/- 15.45). ANOVA and Tukey test showed that salivary contamination provided significant increase in microleakage. Under salivary contamination, only SBF provided complete marginal sealing. When F and KF were compared, the glass-ionomer cement yielded the best sealing.     

不同渗透时间对窝沟封闭边缘封闭性能的影响

目的 研究窝沟封闭剂渗透时间对窝沟封闭边缘微渗漏、渗透程度及超微结构的影响。方法 取离体牙50颗,随机分成5组,每组10颗,每个样本咬合面窝沟处行窝沟釉质成形术,然后酸蚀,冲洗干燥。组1~组5直接涂布封闭剂,组1即刻固化,组2~组5分别停留15 s、30 s、45 s和60 s后光照固化。采用1%亚甲蓝浸染法和体视显微镜观察封闭剂与牙面间的密合程度及封闭剂的渗透程度。用原子力显微镜（atomic force microscope, AFM）观察即刻组及30 s组窝沟封闭剂牙齿交界面的树脂形成情况。结果 窝沟封闭剂牙面停留30 s及以上组的窝沟封闭剂渗透程度显著优于其他渗透时间组,原子力显微镜观察显示即刻组及30 s组树脂突明显,排列密集,清晰规则。结论 光照前封闭剂涂布后可适当停留30 s。     

Porosity of pit and fissure sealants

The aim of this study was to investigate the bulk porosity of a range of pit and fissure sealants. The following materials were included in the study: Concise White Sealant and Delton (chemically cured); Delton (visible light-cured); Helioseal, Visioseal and Prolite (visible light-cured with delivery from the bottle via cannule); Delton, Luma Seal and Prisma Shield (visible light-cured with syringe-type direct delivery systems). Five cylindrical samples, 7 mm in diameter and 1 mm in thickness, were prepared from each sealant and the following parameters were analysed in a computer-controlled mercury porosimeter: (i) total cumulative pore volume; (ii) specific surface area of pores; (iii) percentage total porosity (iv) bulk density; and (v) pore radius distribution. According to the results, the chemically cured sealants exhibited total cumulative pore volume, specific surface area of pores and total porosity. Significant differences were detected within the group of visible light-cured materials. The visible light-cured sealants with syringe-type delivery exhibited the lowest porosity.     

光固化封闭剂与光固化流体树脂窝沟封闭临床效果评价

目的:比较光固化流体树脂与光固化封闭剂在实施窝沟封闭方面防龋成本及保留率的差异。方法:选择上海市7～10岁儿童256名,口腔内至少有1对第一恒磨牙无龋。每名儿童一侧的恒磨牙用光固化流体树脂进行窝沟封闭,另一侧用传统光固化封闭剂进行窝沟封闭,使用便携式牙科椅吸取唾液,并用棉卷隔湿。使用2种方法操作时记录每个牙封闭所用去的棉卷数和操作时间。1a后,检查2种材料在牙面上的保留情况。所有操作均在学校内施行,检查由2名医师用镰形探针进行,采用SPSS10.0软件包对数据进行统计学分析。结果:使用传统光固化封闭剂进行窝沟封闭操作时间每牙需3.53min,而光固化流体树脂组需3.32min(P<0.05)。在封闭剂的保留率方面,光固化流体树脂组显著高于传统的窝沟封闭组(P<0.05)。结论:应用光固化流体树脂进行窝沟封闭,能用较短操作时间达到防龋目的,适合在学校推广应用。     

Utilization of electrical conductivity as an alternative method of assessing marginal leakage of pit and fissure sealants

The electrical conductivity readings of extracted human teeth uere taken: prior to placement of pit and fissure sealants; immediately after placement of the pit and fissure sealants; 2 weeks after immersion of the specimens in distilled water at 37 degrees C; and after 7200 strokes on a toothbrushing machine. The specimens were then immersed in dye for 24 h, sectioned and evaluated for evidence of dye penetration. The electrical conductivity readings were then compared to dye penetration results to determine if a correlation existed. A positive correlation existed between the electrical conductivity readings and dye penetration. Threshold values of electrical conductivity existed (which varied for each sealant) - readings above these threshold values indicated sealant failure or leakage. The possibility of using electrical conductivity as a diagnostic tool is definitely worthy of further research - particularly its potential as an in vivo method of assessing leakage.     

Noninvasive pit and fissure sealing: microtensile bond strength to intact bovine enamel of different pit and fissure sealants in a simplified fissure model

PURPOSE: To measure the microtensile bond strength of different pit and fissure sealants in a simplified fissure model. MATERIALS AND METHODS: Twenty extracted bovine mandibular permanent incisors were randomly divided into 4 groups for treatment: G1: 35% phosphoric acid/Clinpro Sealant; G2: 35% phosphoric acid/Delton; G3: Non-Rinse Conditioner/Dyract Seal; G4: 20% polyacrylic acid/Fuji IILC. Each tooth was sectioned into 6 pieces (4 x 6 mm) of buccal enamel. SEM examination was used to confirm the presence of aprismatic enamel on each tooth. Using a spacer, two pieces of etched enamel were secured to a glass slide at a mean distance of 0.6+/-0.1 mm. The space between enamel substrates was then etched/conditioned and sealed with different materials according to the tested groups. By serially cutting each double-bonded sample, multiple beam-shaped specimens about 0.8mm(2) in cross section were obtained and tested in tension (0.5 mm/min) until failure occurred at either one of the two stressed interfaces. Failure modes were classified by stereomicroscopy. RESULTS: G1 and G2 showed statistically higher bond strengths than G3 and G4. G4 demonstrated the significantly lowest bond strength. Failures were mostly adhesive in G1, G2, G3, and mainly cohesive/mixed in G4. CONCLUSION: According to this model, resin-based materials (Clinpro Sealant, Delton) showed better microtensile bond strength than compomer (Dyract Seal) or resin-modified glass ionomer (Fuji IILC).     

唾液污染后再处理对窝沟封闭边缘封闭性能影响的研究

目的研究窝沟封闭唾液污染后再处理的操作因素对窝沟封闭剂微渗漏、渗透程度及其超微结构的影响。方法取离体牙50颗,随机分成5组,每组10颗,每个样本咬合面窝沟处行窝沟釉质成形术,然后酸蚀,冲洗干燥。A组直接涂布封闭剂,停留30 s后光照固化。B～E组均经人工唾液污染牙面后,分别干燥、冲洗后干燥、冲洗干燥后再酸蚀和冲洗干燥后自酸蚀粘结剂处理,涂布封闭剂,停留30 s后光照固化。采用1%亚甲蓝浸染法和体视显微镜观察封闭剂与牙面间的密合程度及封闭剂的渗透程度。用原子力显微镜(atomic force microscope,AFM)观察各组窝沟封闭剂牙齿交界面的树脂形成情况。结果未污染组和污染后再酸蚀组的微渗漏情况与渗透深度低于唾液污染后其他处理组(P<0.05)。原子力显微镜观察显示封闭剂-釉质交界面自酸蚀组树脂突稀疏不清晰,树脂突之间有混合层,唾液污染组树脂突较稀疏,长短不一,排列不规则,这2组的扫描结果差于未污染组。结论唾液污染后应重新酸蚀处理,而使用自酸蚀粘结剂处理其密合性较差,临床不建议使用。     

2种光固化窝沟封闭剂的防龋效果评价

目的:探讨光固化窝沟封闭剂预防窝沟龋的临床疗效。方法:选择162例6￣8岁儿童的416颗健康恒牙,分为2组,分别采用窝沟釉质成形封闭术和窝沟杯刷清洗封闭术对窝沟进行封闭,比较2种封闭术封闭剂保留率和龋病发生率,并通过自身对照,观察2种封闭术的临床效果,采用SPSS10.0统计软件包进行χ2检验。结果:窝沟釉质成形封闭术3年封闭剂保留率和龋病发生率分别为85.4%、0.9%,窝沟杯刷清洗封闭术3年封闭剂保留率和龋病发生率分别为63.8%、6.7%,2组封闭剂保留率和龋病发生率均有显著性差异(P<0.05)。结论:2种封闭术均有良好的临床疗效,窝沟釉质成形封闭术的防龋效果优于窝沟杯刷清洗封闭术。     

Thermocycling of pit and fissure sealants.

Both sealants experience early thermocyclic failure, which is manifested as marginal breakdown or separation. From the 20 to 70% failure range (Fig 5) Nuva Seal was three times as resistant to thermocyclic stressing as was Epoxylite 9075. That is, the Nuva Seal-sealed teeth had to be cycled three times more than the Epoxylite 9075-sealed teeth to effect the same failure rates. Both Epoxylite and Nuva Seal reach the same failure rate at 7,000 cycles (75% failure rate). Extremely careful visual examination is required to detect marginal separation failures of pit and fissure sealants.     

The use of pit and fissure sealants

This paper reviews key issues of sealant use and methodology and poses recommendations to inform the discussion toward a consensus statement by participants. A comprehensive review of sealant literature, including policy recommendations from previous conferences that reviewed best practices for sealant use, was completed. Building on previous review papers and on previous policy statements by dental and public health groups, this paper discusses key questions about sealant use in light of contemporary caries data and cost-benefit analyses. In addition, newest material advancements are reviewed to establish the next step in sealant improvement for young patients.     

The use of pit and fissure sealants

This paper reviews key issues of sealant use and methodology and poses recommendations to inform the discussion toward a consensus statement by participants. A comprehensive review of sealant literature, including policy recommendations from previous conferences that reviewed best practices for sealant use, was completed. Building on the review paper by Simonsen and on previous policy statements by dental and public health groups, this paper discusses key questions about sealant use in light of contemporary caries data and cost-benefit analyses. In addition, newest material advancements are reviewed to establish the next step in sealant improvement for young patients.