自酸蚀粘结剂应用于年轻恒中切牙冠折修复的效果

目的评价自酸蚀粘结剂用于年轻恒中切牙冠折充填修复治疗的效果。方法选择年轻恒上颌中切牙牙冠牙釉质-牙本质折断而未露髓的患者106例137颗患牙,按抛硬币方法分为试验组和对照组。试验组的56例74颗患牙使用自酸蚀粘结剂处理牙面;对照组的50例63颗患牙常规间接盖髓、酸蚀剂和粘结剂处理牙面。2组用相同光固化复合体修复牙冠外形,调牙合抛光,观察2组修复后1个月、3个月、6个月、1年、2年的疗效。结果治疗后1个月、3个月、6个月、1年、2年,试验组成功率分别为97.30%、97.30%、94.59%、94.59%、94.59%,对照组成功率分别为95.24%、95.24%、90.48%、88.89%、88.89%,试验组成功率高于对照组,但差异均无统计学意义(P>0.05)。结论应用自酸蚀粘结剂粘结充填修复牙釉质-牙本质折断而未露髓的年轻恒中切牙效果良好。     

Combination injuries 2. The risk of pulp necrosis in permanent teeth with subluxation injuries and concomitant crown fractures

Abstract – Background: The reported risk of pulp necrosis (PN) is generally low in teeth with subluxation injuries. A concomitant crown fracture may increase the risk of PN in such teeth. Aim: To analyse the influence of a concomitant trauma‐related infraction, enamel‐, enamel–dentin‐ or enamel–dentin–pulp fracture on the risk of PN in permanent teeth with subluxation injury. Material and Methods: The study included 404 permanent incisors with subluxation injury from 289 patients (188 male, 101 female). Of these teeth, 137 had also suffered a concomitant crown fracture. All the teeth were examined and treated according to a standardized protocol. Statistical Analysis: The risk of PN was analysed separately for teeth with immature and mature root development by the Kaplan–Meier method, the log‐rank test and Cox regression analysis. The level of significance was set at 5%. Risk factors included in the analysis were gender, patient age, crown fracture type, mobility and response to an electric pulp test (EPT) at the initial examination. Results: Teeth with immature root development: The risk of PN was increased in teeth with a concomitant enamel fracture (log‐rank test: P = 0.002), enamel–dentin fracture (log‐rank test: P < 0.0001), enamel–dentin–pulp fracture (log‐rank test: P < 0.0001) and in teeth with no response to EPT at the initial examination [hazard ratio: 21 (95% confidence interval, CI: 2.5–172.5), P = 0.005]. Teeth with mature root development: the risk of PN was increased in teeth with an enamel–dentin fracture [hazard ratio: 12.2 (95% CI: 5.0–29.8), P < 0.0001], infraction [hazard ratio: 5.1 (95% CI: 1.2–21.4) P = 0.04] and in teeth with no response to EPT at the initial examination [hazard ratio: 8 (95% CI: 3.3–19.5), P < 0.0001]. Conclusion: A concomitant crown fracture and no response to EPT at the initial examination may be used to identify teeth at increased risk of PN following subluxation injury.     

Vitapex糊剂和氢氧化钙诱导年轻恒牙根尖形成疗效观察

目的：比较Vitapex糊剂和普通氢氧化钙2种材料诱导根尖成形的疗效。方法：选择76颗牙外伤或已有牙髓病变的年轻恒牙,随机分成两组,分别用Vitapex糊剂、氢氧化钙糊剂行根尖诱导术。结果：经2年的随访观察,根尖诱导成功率Vitapex组为94.73%、氢氧化钙组78.95%,结果经χ2检验差异有统计学意义（P〈0.05）。结论：Vitapex糊剂诱导年轻恒牙根尖成形较普通氢氧化钙糊剂效果更好。     

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骨性Ⅲ类错(牙合)是临床上较为复杂的错(牙合)畸形,严重影响牙齿、颌骨及面部的发育.近年来,随着正畸材料的发展与正畸技术的不断提高,固定矫治器及其矫治技术得到蓬勃发展.本文对恒牙期骨性Ⅲ类错(牙合)畸形的固定矫治研究进展做一综述.     

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牙髓再生治疗的一个重要操作步骤是刺破根尖周组织,使血液进入根管内,这将使根尖周的干细胞也同时进入根管,血凝块为干细胞的聚集提供基质和支架;此外,血液内含有丰富的生长因子,可促进干细胞的增殖和分化,对年轻恒牙牙髓再生治疗后根管内硬组织的沉积和牙根的继续发育起到关键作用。本文就牙髓再生治疗相关机制的研究进展做一综述。     

A randomized double-blind clinical trial of posterior composite restorations with or without bevel: 1-year follow-up

Objective

This randomized double-blind clinical trial compared the performance of posterior composite restorations with or without bevel, after 1-year follow-up.

Material and Methods

Thirteen volunteers requiring at least two posterior composite restorations were selected. Twenty-nine cavities were performed, comprising 14 without bevel (butt joint) and 15 with bevel preparation of the enamel cavosurface angle. All cavities were restored with simplified adhesive system (Adper Single Bond) and composite resin (Filtek P60). A halogen light curing unit was used through the study. Restorations were polished immediately. Analysis was carried out at baseline, after 6 months and after 1 year by a calibrated evaluator (Kappa), according to the FDI criteria. Data were statistically analyzed by Mann-Whitney test (p<0.05).

Results

Beveled and non-beveled cavities performed similarly after 1 year follow-up, regarding to fractures and retention, marginal adaptation, postoperative hypersensitivity, recurrence of caries, surface luster and anatomic form. However, for surface and marginal staining, beveled cavities showed significantly better performance (p<0.05) than butt joint restorations.

Conclusions

It was concluded that the restorations were acceptable after 1 year, but restorations placed in cavities with marginal beveling showed less marginal staining than those placed in non-beveled cavities.     

The effect of temperature changes on adaptation of resin fillings. II

In earlier laboratory investigations of thermal percolation at resinous fillings the duration of the heating periods was too long to be realistic. The aim of the present work was to investigate the effect of repeated heatings of realistic duration on the formation of marginal gaps between filling and tooth during a subsequent cooling below the minimum value in the temperature cycling process. Fillings made in extracted human teeth were studied. The brands investigated were Adaptic, Blendànt, Concise, Opotow, Sevriton Simplified, and Swedon. After closure of the initial gaps by water absorption expansion the fillings were polished and subjected to thermal cycling. The specimens were cycled between either 37° and 50° C or 37° and 60° C, the duration of each immersion in the warmer bath was 2 or 5 seconds, and the number of cycles was 1, 10, 100 or 1000. The effect of the cycling was investigated by measuring the width of marginal gaps appearing at a temperature lower than 37° C. It was found that the width of the gaps was only little affected by thermal cycling between 37° and 50° C. Cycling between 37° and 60° C increased the gap widths only with Opotow, Sevriton Simplified, and Swedon. The data indicate that thermal percolation for a number of brands may be of no clinical importance.     

预防性使用MTA控制外伤恒前牙牙根外吸收的临床疗效观察

目的:探讨牙根发育完成的外伤冠折露髓恒牙使用MTA预防性控制根吸收的临床疗效。方法:对109颗牙根发育完成的冠折露髓恒牙随机分为预防性使用MTA治疗组(55颗)和常规治疗组(54颗),完成根管治疗。2年后,通过临床症状及X线根尖片判断疗效。结果:预防性使用MTA治疗组控制根吸收成功率为98.07%,对照组成功率为86.00%,两组间比较差异有统计学意义(P<0.05)。结论:外伤恒前牙使用MTA预防性控制根吸收临床疗效好,值得临床应用。     

Management of maxillary alveolar bone fracture and severely intruded maxillary central incisor: report of a case

Abstract –  An 11‐year‐old male who injured his maxilla and right maxillary central incisor and lip during a fall was presented to our hospital. His lower lip and upper gingiva were lacerated with swelling and epistaxis, and he had a maxillary alveolar bone fracture and severe intrusion of the right maxillary central incisor, which had penetrated the floor of the nasal cavity with avulsion. Under local anesthesia, we repositioned the incisor and bone segment and fixed them with a titanium micromesh plate and self‐tapping screws and splints. The incisor was also treated by root canal 3 days after the operation and was restored with a crown. We performed root canal filling 1 month later. Five months later, the plate and screws were removed. In prognosis of our case, no symptoms of inflammatory root resorption or ankylosis have observed for more than 1 year and 6 months of follow up based on both clinical and radiographic findings.