Rigidity of commonly used dental trauma splints

Abstract – Background/Aims: The stability of immobilization devices varies from flexible to rigid, depending on the trauma. We evaluated the rigidity of various commonly used splints in vitro Material and Methods: An acrylic resin model was used. The central incisors simulated injured teeth, with increased vertical and horizontal mobility. The lateral incisors and canines stimulated uninjured teeth. Tooth mobility was measured with the Periotest^® device. Vertical and horizontal measurements were made before and after splinting, and the difference between values was defined as the splint effect. We evaluated 4 composite splints, 3 wire‐composite splints, a titanium trauma splint, a titanium ring splint, a bracket splint, and 2 Schuchardt splints Results: For all injured teeth and all splints, there was a significant splint effect for the vertical and horizontal dimensions (P < 0.05). For injured teeth, the composite splints produced the largest changes in vertical tooth mobility; wire‐composite splints 1 and 2, using orthodontic wires, produced the smallest vertical splint effects. For uninjured teeth, the Schuchardt 1 splint and the bracket splint produced the largest splint effects; wire‐composite splints 1 and 2 produced only a slight change in tooth mobility. Composite splints 2 and 3 produced the largest horizontal splint effects for injured teeth, and the 4 composite splints produced the largest horizontal splint effects for uninjured teeth. The most horizontally flexible splints were the titanium trauma splint and wire‐composite splints 1 and 2. Conclusions: According to the current guidelines and within the limits of an in vitro study, it can be stated that flexible or semirigid splints such as the titanium trauma splint and wire‐composite splints 1 and 2 are appropriate for splinting teeth with dislocation injuries and root fractures, whereas rigid splints such as wire‐composite splint 3 and the titanium ring splint can be used to treat alveolar process fractures.     

Rigidity of various fixation methods used as dental splints

Abstract Horizontal and vertical rigidity of teeth fixed with seven types of denial splints were evaluated by two tooth mobility measuring devices. Altogether 21 dissected sheep mandibles including soft tissues were used for the experiments in which Fermit, flexible wire-composite, Kevlar, Fiber, Protemp, rigid wire-composite and Triad Gel splints were applied to four incisors. The mean rigidity of the central incisors within the splint was measured by means of Mühlemann periodontometer (horizontal mobility) and Periotest (horizontal and vertical mobilities). Mobility values of teeth before splinting were used as covariants and the values with the splints were illustrated as adjusted mobility. Statistical significance between the rigidity of various splints was analyzed by an unpaired t-test. It was shown that the most rigid splints both in horizontal and vertical directions were Triad Gel, rigid wire-composite and Fermit splints. Kevlar and Fiber splint allowed more horizontal movement than other splints. Protemp and flexible wire-composite splints proved to produce adequate lateral support for the fixed teeth and allowed vertical flexibility which is experimentally known to improve periodontal healing of luxated teeth.     

Rigidity of various fixation methods used as dental splints.

Horizontal and vertical rigidity of teeth fixed with seven types of dental splints were evaluated by two tooth mobility measuring devices. Altogether 21 dissected sheep mandibles including soft tissues were used for the experiments in which Fermit, flexible wire-composite, Kevlar, Fiber, Protemp, rigid wire-composite and Triad Gel splints were applied to four incisors. The mean rigidity of the central incisors within the splint was measured by means of Mühlemann periodontometer (horizontal mobility) and Periotest (horizontal and vertical mobilities). Mobility values of teeth before splinting were used as covariants and the values with the splints were illustrated as adjusted mobility. Statistical significance between the rigidity of various splints was analyzed by an unpaired t-test. It was shown that the most rigid splints both in horizontal and vertical directions were Triad Gel, rigid wire-composite and Fermit splints. Kevlar and Fiber splint allowed more horizontal movement than other splints. Protemp and flexible wire-composite splints proved to produce adequate lateral support for the fixed teeth and allowed vertical flexibility which is experimentally known to improve periodontal healing of luxated teeth.     

An evaluation of color stability of reinforced composite resin compared with dental porcelain in commonly consumed beverages

The effect of tea, cola, orange juice, and distilled water on the color stability of a porcelain (VITA VMK 95) and a reinforced composite rein (GC Gradia) was evaluated. Standardized specimens for each material was prepared. Specimens from each group were immersed in staining solutions at 50 degree Celsius for 30 days. Tea caused the most significant color change. DeltaE of all of the materials was changed after the immersion in all of the staining solutions during the experimental process.     

In vitro evaluation of the retention of composite fiber and stainless steel posts

PURPOSE: This study compared the tensile retentive strength of composite fiber-reinforced dowels luted with a resin cement to stainless steel dowels luted with zinc phosphate cement. MATERIALS AND METHODS: The crowns of 40 extracted human mandibular premolars were removed with a separating disc 1-mm coronal to the cementoenamel junction. The teeth were randomly divided into 4 groups (n = 10). A post space was prepared in each specimen to a depth of 9 mm, using the drill supplied by the respective manufacturer. For the stainless steel post group, 1.25-mm-diameter posts were cemented with zinc phosphate cement. For the composite fiber reinforced groups, posts with diameters of 1.00, 1.25, and 1.50 mm were luted with a Bisphenol A-Glycidyl Methacrylate (BIS-GMA) resin bonding system (Jeneric/Pentron, Wallingford, CT) according to manufacturer specifications. The specimens were stored in a sealed container with a moist environment for 24 hours, placed in a fixture in an 801 Materials Test Systems (MTS) machine (MTS Systems Corp, Minneapolis, MN), and loaded in tension at a rate of 5.0 mm/min until failure. Differences among the 4 groups were determined using a one-way analysis of variance and Tukey-B post-hoc tests (alpha = 0.05). RESULTS: The mean loads to failure ranged from 43.9 +/- 10.4 kg for the stainless steel dowel group to 19.9 +/- 5.7 kg for the composite fiber-reinforced 1.00-mm-diameter group. The stainless steel post luted with zinc phosphate cement provided significantly greater tensile resistance than all composite fiber dowel groups. The retention of the 1.00-mm composite fiber-reinforced post was significantly less than the remaining groups. CONCLUSIONS: Under the conditions of this study, the stainless steel dowel luted with zinc phosphate cement provided significantly greater retention.     

Management of sleep‐time masticatory muscle activity using stabilisation splints affects psychological stress

To treat sleep bruxism (SB), symptomatic therapy using stabilisation splints (SS) is frequently used. However, their effects on psychological stress and sleep quality have not yet been examined fully. The objective of this study was to clarify the effects of SS use on psychological stress and sleep quality. The subjects (11 men, 12 women) were healthy volunteers. A crossover design was used. Sleep measurements were performed for three consecutive days or longer without (baseline) or with an SS or palatal splint (PS), and data for the final day were evaluated. We measured masseter muscle activity during sleep using portable electromyography to evaluate SB. Furthermore, to compare psychological stress before and after sleep, assessments were made based on STAI‐JYZ and the measurement of salivary chromogranin A. To compare each parameter among the three groups (baseline, SS and PS), Friedman's and Dunn's tests were used. From the results of the baseline measurements, eight subjects were identified as high group and 15 as low group. Among the high group, a marked decrease in the number of bruxism events per hour and an increase in the difference in the total STAI Y‐1 scores were observed in the SS group compared with those at baseline (P < 0·05). No significant difference was observed in sleep stages. SS use may be effective in reducing the number of SB events, while it may increase psychological stress levels, and SS use did not apparently influence sleep stages.     

自制光固化型可塑性纤维桩材料生物安全性的初步评价

目的:初步评价自制光固化型可塑性纤维桩材料的生物安全性.方法:分别通过溶血试验、口腔黏膜刺激试验和短期全身毒性试验(经口途径),评价自制材料的生物安全性.结果:材料溶血率为1.76%,小于中华人民共和国医药行业标准(YY)规定的5%,认为该材料未引发溶血现象,对凝血功能无影响;与材料接触的黏膜未见异常反应,其组织切片观察总评分≤4,根据标准(YY)认为该材料无黏膜刺激性;短期全身毒性实验的受试小鼠无一死亡,其体质量相对增长率和食物利用率与对照组无统计学差异(P＞0.05),心、肾、肝等重要器官肉眼观察无异常改变,其组织切片未见病理改变.结论:自制光固化型可塑性纤维桩材料具有较好的生物安全性.     

Viscoelastic properties of low-shrinking composite resins compared to packable composite resins

The aim of this study was to evaluate the viscoelastic properties of novel low-shrinking composites and compare them to those of packable composites. Six materials were tested: Clearfil Majesty Posterior (CM), ELS Extra Low Shrinkage (EL), Filtek P60 (FP), Filtek Silorane (FS), Prodigy (PR) and Surefil (SU). Static and dynamic testing was performed and materials were tested dry and wet at different temperatures (21°C to 50°C). Shear and flexural modulus, loss tangent, dynamic viscosity, Poisson's ratio and creep recovery were calculated among others. Significant differences were found both between the two groups and between materials belonging to the same group. CM presented the highest shear and flexural modulus and EL the lowest. All materials were softened by an increase of temperature, while FS was the least affected by water and PR showed to be the most susceptible. Different approaches used to overcome polymerization shrinkage lead to materials with different properties.     

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咬合板治疗口颌系统的功能紊乱已有100余年历史,并且至今仍在广泛使用.虽然各种假说一直用来解释其作用,但科学证据不多.普遍认为,咬合板具有保护牙齿不被磨耗的作用,但咬合板在颞下颌关节紊乱痛(TMD)处理中的功效始终很难确定.尽管许多研究认为咬合板减少了夜磨牙发生的频率,但并不表明这会消除磨牙症.戴用咬合板会使咀嚼肌和关节疼痛减少,但也可能是安慰剂效应和症状随时间而自然回归的结果.最新的系统回顾和Meta分析显示,合理调改硬质稳定咬合板对治疗TMD疼痛有效,有证据表明其他类型的咬合板包括软质稳定咬合板、再定位咬合板、松弛咬合板也有一些减少TMD疼痛的功效,但其潜在的副效应也存在,建议在密切监测下使用.本文对目前临床上使用的咬合板的种类及其作用机制进行了评述,重点对咬合板特别是稳定咬合板的作用、治疗价值、应用和注意事项等进行了介绍.强调合理选用和调改咬合板是治疗口颌系统功能紊乱能否成功的关键因素.