目的:(1)比较以聚乙烯硅氧烷印模材料为基质,在前后区域制作临时固定局部义齿时,不同树脂材料在牙髓腔中的温升。(2)根据适合前后临时固定局部义齿制造的散热量,确定一种优良的预备材料。
方法:临时牙冠和牙桥是固定修复的组成部分。已经观察到,常规的固定假体时间化材料由于放热聚合反应而释放热量。当这种临时材料直接放在重要的牙齿上时,根据变化的程度,热传递会导致牙髓组织发生不可逆的变化。因此,这项研究观察了在时间化过程中各种材料的发热量,通过模拟类似的条件。
方法:制作了两个模型,一个模拟缺失的侧切牙(模型A),另一个模拟缺失的第一磨牙(模型B)。选择模型A的完整上颌中切牙和犬齿以及完整的下颌第二前磨牙和第二磨牙作为基台。这些邻接齿在其牙髓腔内装有K型热电偶的尖端,并将其连接到数字温度计。通过直接技术选择了五种临时材料来制造临时牙冠。(1)聚甲基丙烯酸甲酯(自固化丙烯酸),(2)双丙烯酸复合材料(Protemp4),(3)可见光固化聚氨酯二甲基丙烯酸酯(RevotecLC),(4)钡玻璃和气相二氧化硅浸渍的甲基丙烯酸酯(Dentsply完整性)和(5)纳米杂化复合材料(VOCO结构3)。对每个模型上的每种临时材料进行了十次观察。每次观察,从应用时间起,以30s的间隔记录温度上升,通过峰值,直到观察到温度下降。聚乙烯基硅氧烷被用作除光固化树脂外的所有基体,其中使用聚丙烯片材。
方法:用于统计学的方差分析。
结果:ANOVA检验表明,与使用的临时修复材料相关的温度变化存在显着差异。在这五个人中,聚甲基丙烯酸甲酯(自固化树脂)显示出最大的温度上升,其次是双丙烯酸复合材料(Protemp4),可见光固化聚氨酯二甲基丙烯酸酯(RevotecLC),钡玻璃和气相二氧化硅注入的甲基丙烯酸酯(DentsplyIntegrity)和纳米杂化复合材料(VOCO结构3)。模型A和模型B之间没有可比的差异,但在模型B中观察到温度升高的总体降低。
结论:VOCO结构3显示纸浆室中温度升高最小,模型B的整体温度升高较小,这可归因于残余牙本质厚度。
OBJECTIVE: (1) To compare the temperature rise in the pulp chamber with different resin materials used for making provisional fixed partial dentures in anterior and posterior region while using Polyvinylsiloxane impression materials as matrix. (2) To identify a superior provisionalization material based on the amount of heat dissipated suitable for anterior and posterior provisional fixed partial denture fabrication.
METHODS: Temporary crowns and bridges are integral to Fixed Prosthodontics. It has been observed that conventional fixed prosthesis temporisation materials release heat due to the exothermic polymerisation reaction. When such a provisional material is directly let to set on a vital tooth, the heat transfer causes irreversible changes in the pulp tissue depending of the degree of change. Hence, this study observes amount of heat generation in various materials during temporisation procedure, by simulating similar conditions.
METHODS: Two Models were fabricated, one simulating missing lateral incisor (Model A) and another simulating missing first molar (Model B). Intact maxillary central incisors and canine for Model A and intact mandibular Second Premolar and Second Molar were selected to act as abutments. These abutment teeth were fitted with the tip of a K-type Thermocouple inside their pulp chambers and these were connected to a digital thermometer. Five temporisation materials were chosen for fabrication of temporary crowns through Direct technique. (1) polymethy methacrylate (Self Cure acrylic), (2) bisacryl composite (Protemp 4), (3) visible light cure urethane dimethacrylate (Revotec LC), (4) barium glass and fumed silica infused methacrylate (Dentsply Integrity) and (5)nano-hybrid composite (VOCO Structur 3). Ten observations were made for each provisional material on each model. During each observation, temperature rise was recorded at 30s interval from the time of application, through the peak and till a decrease in temperature is observed. Polyvinyl siloxane was used as matrix for all except light cure resin, where polypropylene sheet was used.
METHODS: Anova test used for statistical.
RESULTS: ANOVA test revealed that there was a significant difference in the temperature changes associated with the provisional restorative materials used. Among the five, polymethy methacrylate (self cure resin) showed the maximum rise in temperature, followed by bisacryl composite (Protemp 4), visible light cure urethane dimethacrylate (Revotec LC), barium glass and fumed silica infused methacrylate (Dentsply Integrity) and nano-hybrid composite (VOCO Structur 3). There was no comparable difference between Model A and B but an overall reduction of temperature rise was observed in model B.
CONCLUSIONS: VOCO Structur 3 showed the least temperature rise in the pulp chamber, and overall temperature rise was less for model B which can be attributed to the residual dentin thickness.