Effect of simulated pulpal microcirculation on intrapulpal temperature changes following application of heat on tooth surfaces

Aim  To evaluate ex vivo whether a simulated pulpal microcirculation inside a pulp chamber influenced intrapulpal temperature rise following application of heat on tooth surfaces.
Methodology  An ex vivo model that allowed the circulation of 37 °C warm water inside the pulp chamber of an extracted human tooth was designed. The experimental model resembled pulpal microcirculation. After application of specific thermal stimuli for 30 s to the external surface of 15 maxillary central incisors, lateral incisors and canines, temperature changes were measured in the pulp chamber. The Greenhouse–Geisser and Bonferroni tests were used for analysis of the data. The level of significance was set at 0.05.
Results  Significant differences were found in all three groups of teeth between temperature measurements with or without intrapulpal water flow. Additionally, temperature changes resulting from the application of different stimuli to the group of lateral incisors were significantly greater compared with the other groups of teeth ( P  < 0.05).
Conclusions  The importance of the cooling effect of simulated pulp microcirculation in the thermal behaviour of the dentine was established. Thickness of tooth tissue influenced significantly pulp temperature rise ex vivo .     

Effect of simulated pulpal microcirculation on intrachamber temperature changes following application of various curing units on tooth surface

Objective

The purpose of this study was to evaluate ex vivo the rise in intrachamber temperature induced by the application of various curing units on tooth surface, under conditions of continuous water flow inside the pulp chamber simulating pulp microcirculation.

Methods

Fifteen extracted intact human teeth were selected. Intrachamber temperature increases were induced by applying the following curing units to the buccal aspect of the tested teeth: a conventional halogen lamp, two high-intensity halogen lamps, a plasma arc curing light, a mercury/metal-halide lamp, and a diode laser. Temperature changes on the tooth surfaces were recorded using thermocouples connected to a data logger. The Greenhouse–Geisser and Bonferroni tests in the SPSS software package were used for analysis of the data. The level of significance was set at 0.05.

Results

Under conditions of water flow the average intrachamber temperature rise was less than 6 °C, for all curing units. Without water flow, the increase in pulp temperature exceeded 6 °C for all units except the conventional halogen lamp. The diode laser produced a significantly greater temperature increase than any other curing unit. Application of the diode laser and the two high-intensity halogen lamps to lateral incisor specimens produced significantly greater temperature increases than other teeth.

Conclusions

When the simulated pulp microcirculation was absent, the temperature increases produced by all curing units except the conventional halogen lamp were large enough to be potentially harmful to the pulp. On the contrary, with the cooling effect of water flow inside the pulp chamber, all units proved to be safe for use.     

��ͬ�׹ⷽ���������ܸ��Ͻ���������Ӱ���о�

目的比较不同抛光方法对钴铬合金离子析出的影响。方法本研究于2013年3—8月在福建医科大学附属口腔医院进行。制作30个钴铬合金试样,随机分为5组,分别为砂纸抛光组、镜面抛光组、橡皮轮抛光组、电解抛光组和化学抛光组,每组6个试样。根据ISO10271：201l标准采用浸泡实验检测试样Co、cr离子的析出情况。检测腐蚀前的表面粗糙度和腐蚀前后表面形貌。结果镜面抛光组co、cr析出量之和小于橡皮轮抛光组、电解抛光组和化学抛光组（P〈0．05）。化学抛光组表面粗糙度最大（P〈0．05）。化学抛光组co、cr析出量及其总和均大于砂纸抛光组、镜面抛光组、橡皮轮抛光组、电解抛光组（P〈0．05）。扫描电镜观察表明,砂纸抛光组、橡皮轮抛光组、化学抛光组表面有明显的腐蚀痕迹。结论钴铬合金经镜面抛光可获得最好的表面形貌和抗腐蚀性能,化学抛光对钴铬合金表面形貌改善不大,其抗腐蚀性能最差。     

Glutamate control of pulpal blood flow in the incisor dental pulp of the rat

Glutamate is present in primary sensory afferents innervating the dental pulp and is known to exert vasoactive effects. The aims of this study were (i) to assess pulpal blood flow (PBF) after glutamate infusion in the dental pulp and (ii) to observe the distribution of glutamatergic nerve fibers expressing the vesicular transporters of glutamate (VGluT). The PBF was monitored with laser Doppler flowmetry before and after glutamate (0.5 M) infusion in the dental pulp vs. saline infusion. Immunochemistry for VGluT1, 2, and 3 was performed in addition to immunochemistry for the vascular and neuronal markers smooth‐muscle actin (SMA), isolectin B4 (IB4), and calcitonin gene‐related peptide (CGRP). Glutamate infusion resulted in a PBF increase that lasted for 60 s. Positive immunolabeling was observed for the three glutamate transporters, but was more pronounced for VGluT3. Moreover, VGluT3 immunoreactivity was observed within nerve fibers entering the dental pulp and terminating at the periphery and at the vicinity of odontoblasts. Also, VGluT3 was colocalized with the vascular marker SMA, and in some nerve fibers with IB4, but not with CGRP. This study provides support for a control of dental pulp microcirculation by neurons expressing VGluT3.     

Evaluation of the temperature of different refrigerant sprays used as a pulpal test

The temperature of different refrigerant sprays (Endo‐Ice, Endo‐Frost, Coolermatic and Sprayon Contact and Tuner Cleaner) used as pulpal tests were evaluated in vitro. A thermocouple placed inside the pulp chamber of a maxillary central incisor was used to register the temperature changes when the refrigerant sprays were applied with a cotton swab, for 10 s. Results indicate that Endo‐Ice and Endo‐Frost presented the lowest temperatures among the refrigerant sprays tested. Temperatures measured inside the pulp chamber, however, were statistically similar in all groups.     

Effects of cooling and heating of the tooth on pulpal blood flow in man

Abstract Laser Doppler flowmetry (LDF) was used to study the changes in pulpal blood flow (PBF) evoked by application of cold or heat to the palatinal surfaces of teeth 11 or 21 in nine young subjects. Switching from a thermode temperature of 33° to 5° G on average induced a slow decrease of PBF to about 80% of control, and also warming to 39°C evoked a small reduction in most subjects. Inter individual differences were large, however, and both cooling and warming sometimes triggered a rise in PBF. In contrast, skin blood flow, as recorded with LDF in the forearm, invariably rose during warming and fell during local cooling. The results suggested a more complex interaction between local and nervously mediated effects of moderate changes in temperature in the tooth pulp than skin, and that the previous held view of cold and heat decreasing and increasing PBF, respectively, is wrong.     

Effect finishing and polishing procedures on the surface roughness of IPS Empress 2 ceramic

Abstract

Objective. To evaluate the surface roughness of IPS Empress 2 ceramic when treated with different finishing/polishing protocols. Materials and methods. Sixteen specimens of IPS Empress 2 ceramic were made from wax patterns obtained using a stainless steel split mold. The specimens were glazed (Stage 0–S0, control) and divided into two groups. The specimens in Group 1 (G1) were finished/polished with a KG Sorensen diamond point (S1), followed by KG Sorensen siliconized points (S2) and final polishing with diamond polish paste (S3). In Group 2 (G2), the specimens were finished/polished using a Shofu diamond point (S1), as well as Shofu siliconized points (S2) and final polishing was performed using Porcelize paste (S3). After glazing (S0) and following each polishing procedure (S1, S2 or S3), the surface roughness was measured using TALYSURF Series 2. The average surface roughness results were analyzed using ANOVA followed by Tukey post-hoc tests (α = 0.01) Results. All of the polishing procedures yielded higher surface roughness values when compared to the control group (S0). S3 yielded lower surface roughness values when compared to S1 and S2. Conclusions. The proposed treatments negatively affected the surface roughness of the glazed IPS Empress 2 ceramic.     

抛光方法对钴铬合金铸造全口义齿密合度的影响

［摘要］ 目的 探讨5种抛光方法对钴铬合金铸造全口义齿密合度的影响。方法 铸造上颌钴铬合金全口基托板30个,随机分为6组,1组作为对照,5组分别用光整、电解、打磨、打磨后电解、打磨后光整等5种方法抛光。在相当于上颌第二磨牙远中部位切断义齿基托与标准模型,数字万能工具显微镜分别测量上颌全口义齿基托组织面与标准模型齿槽嵴顶点、腭中缝点及其两者的中点之间共5个部位的间隙,并用电子数显卡尺测量5个点的基托板厚度。结果 6组铸造基托板的厚度,除了光整组试样的厚度与抛光前试样厚度无统计学差别外(P>0.05),其余各组均与抛光前试样厚度有统计学差别(P<0.01)。抛光前、后5点间隙值没有组间统计学差别(P>0.05)。结论 5种抛光方法对上颌铸造全口基托的密合度无影响。     

An evaluation of the use of tooth temperature to assess human pulp vitality

AIM: To evaluate change in tooth surface temperature following a thermal stimulus as a simple and reliable method to assess the presence and the extent of blood flow through teeth. METHODOLOGY: Miniature thermometers were used to measure the relationship between surface temperature of teeth and internal flow of 37 degrees C water (in vitro) or blood (in vivo). In addition, thermal stimuli were applied to the external surface of the teeth, and the rate of temperature recovery was related to internal flow. RESULTS: Under in vitro conditions, the surface temperature of teeth and rate of temperature recovery were related to the rate of internal water flow. However, in vivo neither standing surface temperature (P = 0.47) nor rate of temperature recovery (P = 0.19) were significantly related to evidential pulp vitality. CONCLUSION: Change in the surface temperature of teeth is not suitable as a simple clinical means to assess pulp vitality.     

Subcutaneous emphysema related to air‐powder tooth polishing: a report of three cases

Subcutaneous emphysema is a rare complication of dental procedures and can occasionally give rise to potentially life‐threatening complications. We describe three cases of subcutaneous emphysema diagnosed in the same dental clinic. All cases occurred during tooth or implant cleaning using air polishing (KavoProphyflex^®) with a sodium bicarbonate powder (Air‐N‐Go Classic^®). The diagnosis was based on clinical findings and was confirmed radiologically. The cervical and facial regions were affected in all three cases, and spread to the mediastinum occurred in one case. All the episodes resolved within 3–5 days. Tooth cleaning using air polishing combined with an abrasive powder is a risk factor for subcutaneous emphysema, especially when the powder and device are from different manufacturers. Radiological assessment must be performed to rule out involvement of deep tissue planes.     

Effects of mandibular nerve block on heat- or cold-induced changes in pulpal blood flow in man

Abstract – Laser Doppler flowmetry (LDF) was used to study the effect of mandibular nerve block, using 3% mepivacain, on heat-or cold-induced changes in pulpal blood flow (PBF) evoked by application of cold or heat to the lingual surfaces of teeth 33 and 43 in nine young subjects. PBF on average showed a 7% increase in response to heat (48°C) and a 20% decrease when exposed to cold (3°C). Neither response was affected by mandibular block. From this we concluded that the effects on PBF of the presently applied heating and cooling of the tooth were solely due to direct thermal influences on the blood vessels, without involvement of vasomotor or sensory nerves.     

三种抛光系统对不同光固化复合树脂表面粗糙度影响的实验研究

目的：采用临床上常用的3种充填用光固化复合树脂,经过3种不同抛光系统处理后,观测其表面粗糙度的变化。方法：选择3种临床常用的前后牙通用光固化型复合树脂（FiltekZ250,SpectrumTPH,CHARISMA）,分别用3种抛光系统（sof—lex,Enhance,Super—Snap）修整、抛光,应用表面粗糙度仪测定其粗糙度,扫描电镜观察抛光后的表面形貌,然后对检测结果进行统计学分析。结果：3种复合树脂经不同抛光系统处理后,两因素析因设计方差分析检验树脂材料和抛光系统之间的相互关系,结果显示,二者之间具有交互作用。用Sof—lex处理FiltekZ250树脂可获得最低的Ra值,但Super-snap抛光套装处理各种复合树脂组间无显著差异,均能达到较低的粗糙度值。结论：（1）临床上常用的3种光固化复合树脂材料中,FiltekZ250与SpectrumTPH、CHARISMA相比有更好的抛光性能,可形成比较平整光滑的表面;（2）不同抛光系统和不同树脂之间存在交互作用,Sof-lex和Super—snap最适宜处理FiltekZ250树脂,抛光后的表面光滑;Super-snap抛光系统对3种不同复合树脂进行处理后,均能达到较低的粗糙度值,明显优于其它2种抛光系统。     

5种抛光方法对钴铬烤瓷合金抗腐蚀性能的影响

目的 研究5种抛光方法对钴铬烤瓷合金抗腐蚀性能的影响.方法 制作30个钴铬烤瓷合金试样,随机分为5组,分别采用砂纸、金相布轮、橡皮轮、电解和化学方法进行抛光,测量试样的表面粗糙度.用浸泡实验检测试件在腐蚀液中浸泡后Co、Cr离子的析出量,并用扫描电镜观察试样浸泡前后的表面形貌.结果 电解抛光会破坏钴铬烤瓷合金试样,终止后续浸泡实验;化学抛光组表面粗糙度最大,为(0.35 ±0.09) μm,与其他组差异有统计学意义(P＜0.05).腐蚀液浸泡7d后,金相布轮抛光组试件Cr析出量最小,为(0.47 ±0.17) μg/cm2;化学抛光组试件Cr析出量最最多,为(2.34 ±0.76) μg/cm2,差异有统计学意义(P＜0.05).扫描电镜观察腐蚀液浸泡前的试件,金相布轮抛光和橡皮轮抛光可获得光滑表面,砂纸抛光和化学抛光后表面划痕明显;腐蚀液浸泡后各组表面划痕没有显著变化.结论 钴铬烤瓷合金采用金相布轮和橡皮轮抛光可获得较好的表面形貌和抗腐蚀性能,化学抛光对钴铬烤瓷合金表面形貌改善不大,其抗腐蚀性能最差.     

不同抛光方法对钴铬合金铸造义齿表面粗糙度及精度的影响

目的研究不同抛光方法对钴铬合金铸造义齿表面粗糙度及精度的影响。方法(1)制作30个30mm×10mm×1.5mm钴铬合金试件,选择1组作为对照组,其余各组分别用5种方法抛光光整技术、电解、打磨、打磨后再电解、打磨后再光整,测量其表面粗糙度;(2)铸造钴铬合金基托30个,选择1组作为对照组,其余各组用5种方法抛光,在相当于上颌第二磨牙远中部位切断义齿基托与标准模型,测量基托组织面与标准模型间5个部位的间隙。用SPSS13.0软件对数据进行方差分析。结果(1)抛光前,试件表面粗糙度值最大(Ra3.38μm),手工打磨后再光整组粗糙度值最小(Ra0.19μm)。除光整组、电解组试件之间的差别无统计学意义外(P>0.05),其余各组差别均有极显著统计学意义(P<0.01)。(2)各组试件的精度值在抛光前、后无统计学差异(P>0.05)。结论手工打磨后再进行光整的铸件表面粗糙度最低,光整抛光方法对上颌铸造基托的精度无影响。     

Effect of restorations on pulpal blood flow in molars measured by laser Doppler flowmetry

Aim  To: (i) compare laser Doppler pulpal blood flow (PBF) signals from restored and unrestored first molar teeth, (ii) investigate PBF in teeth with large and small restorations, and (iii) to relate PBF to pulp chamber dimensions on radiographs.
Methodology  Bitewing radiographs of young adults with restored first molars were obtained and pulp chamber dimensions measured. Subjects were divided into 2 groups: group A with a restored tooth and an unrestored contralateral (43 subjects) and group B, those with a molar with a small (usually occlusal) restoration whilst the contralateral tooth had an extensive occlusal restoration (or restorations) or restored proximal surface(s) and/or cuspal overlay (31 subjects). The 148 teeth responded to electric pulp testing, and their PBF was recorded using a laser Doppler flowmeter. Data were analysed using Student's t -test.
Results  In group A the PBF in the restored teeth was significantly lower than in unrestored contralaterals ( P  =   0.028) and the total pulp chamber area and that in the clinical crown were smaller ( P  =   0.039 and 0.021 respectively). The group B molars with large restorations had significantly lower PBF than contralaterals with small restorations ( P  =   0.001), and their total pulp chamber area and pulp chamber width at cervix were reduced significantly ( P  =   0.003 and 0.032 respectively).
Conclusions  In molars the size of the pulp chamber was influenced by the presence of restorations and the PBF was reduced when restorations were present. Size and extent of restorations had a significant effect on PBF.     

Studies on polishing of Ti and Ag-Pd-Cu-Au alloy with five dental abrasives

Titanium (Ti) and Ag-Pd-Cu-Au alloy were examined for their polishing behaviour by conducting manually controlled polishing tests using five dental abrasives [carborundum point (CR) and silicone points (R1 and R2)] driven by a high torque micromotor with rotational speeds ranging from 2000 to 15 000 r.p.m. Polishing of Ti resulted in less volume of removal upon polishing, a rougher surface and larger loss of abrasives, compared with polishing of Ag-Pd-Cu-Au alloy. Polishing of Ti with a rotational speed of 15 000 r.p.m. led to the largest volume of removal upon polishing, whilst that of 10 000 r.p.m. produced the optimal volume for Ag-Pd-Cu-Au alloy. It was concluded that Ti was much more difficult to polish, requiring special care (e.g. frequent exchange of abrasives). Development of new abrasives for polishing Ti is required.     

Effect of luxation injuries on permanent teeth

Abstract Trauma to the supporting tissues of the teeth are among the most common dental injuries, leading to such complications as pulp canal obliteration, necrosis and root resorption. The aim of this investigation was to study the outcome for young permanent teeth subjected to luxation injuries. From 108 dental records 171 teeth with injuries to the supporting tissue were selected. The material comprised 130 subluxated, 15 extruded, 9 intruded, 15 exarticulated and 6 laterally luxated teeth in children aged 6–19 years. Apart from luxation, 59 teeth (35%) had additional crown and root fractures. 65% of the teeth recovered without complications. 78% of the subluxated teeth and 24% of the luxated teeth showed uneventful posttraumatic healing. Concomitant uncomplicated crown fractures or root fractures without displacement of the coronal fragment did not interfere with the healing. Of 60 teeth with healing complications, 52 (87%) were subsequently recorded as healed, the remaining 8 were extracted or had progressive root resorption. Loss of pulp vitality and external root resorptions were the most often recorded complications (28% and 17% of the total material respectively). Pulp canal obliteration was noted in 3% of the cases. Extent of injury and degree of tooth maturity were found to be related to healing compliations.