Micro-CT observation of rat dental pulp healing after pulpotomy in in vivo study

We report the newly developed Micro-CT, which allows us to observe the individual animal over a long experimental period and to compare changes in pulp tissue in relation to growth and aging without considering individual differences. Further, we used pathological examination to prove similar the result observing from Micro-CT. We have examined wound healing of teeth after pulpotomy in rats, and could clearly observe histopathological changes in the affected teeth and the absorption of temporary filling material and pulp capping agents. In cases with breakage of the dental crown, the CT images agreed with the pathological observations, and it was possible to estimate the time of breakage. In vivo Micro-CT is possible to apply in continuous recording of small experimental animals, such as rats, under anesthesia and the result is sufficiently high. High-quality image was obtained in of the entire head region of the rat. It was suggested that this method can be used for long-term continuous observation of changes in the teeth conditions after pulpotomy in experimental animals. We report the newly developed Micro-CT, which allows us to observe the individual animal over a long experimental period and to compare changes in pulp tissue in relation to growth and aging without considering individual differences.     

两种生物陶瓷材料用于乳磨牙牙髓切断术的随机对照研究

目的通过比较新型生物陶瓷材料iRoot BP Plus和三氧化矿物凝聚体(mineral trioxide aggregate,MTA)作为盖髓剂在乳磨牙牙髓切断术应用中的成功率,探讨iRoot BP Plus的临床应用价值。方法按照纳入和排除标准收集2018年8至12月于北京大学口腔医学院·口腔医院儿童口腔科行全身麻醉下治疗,口内至少有1对及以上同名乳磨牙龋坏须行牙髓切断术的3至8岁患儿,采用简单随机分组方法分别使用iRoot BP Plus(试验组)和MTA(对照组)行牙髓切断术,术后3、6及12个月随访,拍摄患牙根尖X线片,收集患牙治疗前后自觉症状、临床检查及影像学表现,计算两组的治疗成功率,并分析影响成功率的因素。结果研究共纳入患儿20例,男女各10例,共计28对、56颗乳磨牙(试验组28颗,对照组28颗),其中随访满1年者共23对、46颗乳磨牙。试验组3、6、12个月的治疗成功率分别为96%(25/26)、92%(22/24)和87%(20/23),对照组分别为100%(26/26)、96%(23/24)和96%(22/23),两组术后3、6、12个月的成功率差异均无统计学意义(P>0.05)。切髓后止血时间显著影响试验组的成功率(P<0.05)。结论iRoot BP Plus与MTA用于乳磨牙牙髓切断术1年随访期内均取得了较好的治疗效果,iRoot BP Plus在乳牙牙髓切断术中具有良好的临床应用前景。     

Success rate of three capping materials used in pulpotomy of primary molars: A randomized clinical trial

BackgroundCarious primary molars, symptomless, or with reversible pulpitis are most frequently treated with pulpotomy to maintain arch integrity, otherwise they would be extracted. The present study was conducted to assess clinically and radiographically the success rate of three capping materials: Nanohydroxyapatite (NHA), Mineral Trioxide Aggregate (MTA), and Formocresol (FC) in pulpotomy of primary molars.MethodsA clinical trial was carried out on healthy, four to eight years old children, with 72- second primary molars indicated for pulpotomy. Molars were divided into 3 equal groups (24 teeth each) designated to NHA (group 1), MTA (group 2), and FC (group 3) as pulp medicaments. Treated teeth were finally restored with stainless steel crowns. Subjects were monitored clinically and radiographically after three, six, and twelve months. Statistical analysis was presented as intended to treat analysis. Categorical data were analyzed using Fisher’s exact test. The significance level was set at p ≤ 0.05. Statistical analysis was performed using SPSS, version 26.ResultsBy the end of the twelve months, the number and percentages of successfully treated molars for Group (1), Group (2) and Group (3) were 10 (41.7%), 19 (79.2%) and 18 (75.0%) respectively; with (NHA) group showing a significantly lower rate of success, (p = 0.019).ConclusionsMTA is still the material of choice for pulpotomy in primary molars.Trial RegistrationThis trial was registered on Clincal.Trial.gov (https://clinicaltrials.gov), on February 8, 2019 (Retrospectively registered). The protocol ID is 181053. The Identifier is NCT03833557.     

辛伐他汀凝胶盖髓剂初步研究Ⅰ

目的:制备辛伐他汀温敏性凝胶缓释系统,初步探索辛伐他汀促进牙髓修复的作用。方法:制备辛伐他汀壳聚糖温敏性缓释凝胶,紫外分光光度法检测缓释效果并绘制释放曲线。大鼠磨牙行活髓切断术,分别以载有辛伐他汀的壳聚糖缓释凝胶(简称辛伐他汀缓释凝胶)、壳聚糖/甘油磷酸钠凝胶(简称空白凝胶)、氢氧化钙盖髓,并设对侧为空白对照组,术后1、3、7、14、28 d处死,拍摄X线片,HE染色观察牙髓情况。结果:37℃下,空白凝胶15 min内凝固,辛伐他汀缓释凝胶8 min内凝固。48 h辛伐他汀快速释放,60 d后达到溶质梯度平衡,凝胶内的辛伐他汀持续平稳释放,累计释放率为61.5%。活髓切断术后,氢氧化钙组28 d受试牙根管口见高密度钙化屏障,辛伐他汀缓释凝胶组术后7、14、28 d的根管口见高密度钙化屏障,空白凝胶组未见高密度影像。HE染色结果显示,辛伐他汀组术后7 d盖髓断面牙髓结构正常,成牙本质样细胞向断面聚集并形成早期钙化团块,28 d形成早期钙化桥;氢氧化钙组术后7 d表现为盖髓剂下方断面和髓腔内牙髓组织凝固性坏死现象,失去正常结构,与周围组织界限明显。结论:辛伐他汀缓释凝胶缓释性能良好。作为盖髓剂,其组织相容性好,有促进修复性牙本质形成的潜能。     

Efficacy of Alternative Medicaments for Pulp Treatment in Primary Teeth in the Short Term: A Meta-analysis

ObjectiveThis systematic review and meta-analysis aimed to evaluate the overall, clinical, and radiographical success rates of alternative pulpotomy medicaments in primary teeth.MethodsA systematic search of five databases was conducted following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Prospective clinical trials using alternative pulpotomy medicaments in children were included. The outcome measures were overall, clinical, and radiographic success, expressed in percentages and converted to odds ratios. Fifteen articles were included in the meta-analysis.ResultsCombined odds ratios for overall, clinical, and radiographic success was 0.55 (95% confidence interval [CI]: 0.12-2.41; P = .42; I² = 76%), 1.03 (95% CI: 0.57-1.86; P = .92; I² = 0%), and 0.84 (95% CI: 0.54-1.47; P = .66; I² = 34%), respectively. The results suggest an inconclusive outcome in the success rate of alternative medicaments.ConclusionsThere is insufficient evidence to support the efficacy of alternative pulpotomy medicaments for use in primary teeth. Further robust studies are required before such alternative medicaments should be used in clinical practice.     

新型生物陶瓷材料用于乳磨牙牙髓切断术的临床疗效

目的: 对新型生物陶瓷材料iRoot BP Plus和三氧化矿物凝聚体(mineral trioxide aggregate, MTA)作为盖髓剂应用于乳磨牙牙髓切断术的疗效进行评价,比较两者成功率,并分析影响因素。方法: 通过检索北京大学口腔医院电子病历数据库,筛选2017年1月至2018年12月期间于北京大学口腔医院儿童口腔科门诊就诊、有乳磨牙诊断为慢性牙髓炎、行牙髓切断术的患儿,选择符合纳入标准且盖髓剂为iRoot BP Plus或MTA的患牙,盖髓剂为iRoot BP Plus的患牙全部纳入实验组(iRoot BP Plus组),使用倾向评分匹配法选择性别、年龄、牙位、医生级别、牙髓状态、冠部修复方式和随访时长作为协变量进行1 ∶ 1匹配盖髓剂为MTA的患牙纳入对照组(MTA组)。收集各组患牙治疗前自觉症状、临床检查、影像学表现、治疗情况、随访情况,比较两组治疗成功率,并分别分析影响因素。结果: 共纳入132例患儿,178颗患牙,每组各89颗,平均随访时间(462±99) d,截止至2019年12月,iRoot BP Plus组和MTA组成功率分别为89.9%、93.3%,iRoot BP Plus组成功率稍低于MTA组,差异无统计学意义。通过Cox比例风险模型进行分析发现,牙髓状态的好坏显著影响iRoot BP Plus组的治疗成功率,而年龄、牙位、医生级别、冠部修复方式对成功率均无显著影响。结论: iRoot BP Plus作为盖髓剂应用于乳磨牙牙髓切断术可以取得与MTA相似的治疗效果,牙髓状态是影响治疗效果的主要因素,其远期疗效及影响因素仍需进行更大样本、更长随访时间的研究。     

Possibility of application of calcium carbonate in pulpotomy of rat molars

We investigated restitution processes in mechanically exposed rat molar pulp during pulpotomy with calcium carbonate (CC). The results of the CC treatment were then compared with Calvital^®-containing calcium hydroxide (CH). Micro-computerized tomography (micro-CT), hematoxylin and eosin (H&E) staining and immunoreactivity for nestin, dentin matrix protein-1 (DMP-1) and osteopontin (OPN) were also analyzed. The increment of dentinlike calcified tissue in the pulp was observed by micro-CT. Both CC and CH groups induced pulpotomy resulted in changes associated with inflammation followed by progressive odontoblasts differentiation, dentin matrix secretion and dentin-like bridge formation. Necrotic layer formation and moderate to severe inflammation occurred during the early stages in the CH group. Necrotic layer formation was not observed in the CC group and only associated with mild to moderate inflammation. Immunoreactivity of nestin was observed earlier in the CC group than the CH group. In the CC group, immunoreactivity of DMP-1 was identified beneath the amputated site after 7 days, before increasing until 28 days, and immunoreactivity of OPN was observed in the dentin-like bridge at 28 days, which was also similar to the CH group. These findings suggested that the primary processes of reparative dentinogenesis after pulpotomy with CC may involve natural pulpal wound-healing mechanisms that are similar to the restitution processes observed during pulpotomy with CH. However, CC may prove to be less irritation and more calcified tissue formation than traditional CH-based materials when used as a pulpotomy agent.     

The efficacy of Portland cement as a pulpotomy agent in deciduous teeth

PurposeThe objective of this study was to compare the efficacy of Portland cement (Pc) in comparison with Mineral Trioxide Aggregate (MTA) as a pulpotomy agent in primary molars.Materials and methods64 Deciduous Mandibular Second Molar of children aged between 6 and 8 years were randomly distributed to either PC or MTA groups which was treated by a conventional pulpotomy technique. The teeth were restored with resin modified glass ionomer cement and stainless-steel crowns. All teeth were assessed clinically and radiographically for success and followed at 3, 6 and 12 months.ResultsAt 12 months follow-up, the Clinical success rates of MTA and PC were 100% and 93.3% respectively. The radiographic success rate of MTA after 12 months was 96.7% while PC was 93.3% respectively. However, the results showed no significant difference between the two groups.ConclusionThis study finding showed that PC can be used a as pulpotomy agent with high clinical and radiographic success rates similar to MTA. PC may serve as a good alternative to MTA for pulpotomies of primary teeth.     

活髓切断术应用于龋源性露髓恒牙的初步研究

［摘要］目的 将活髓切断术应用于牙根已经发育完成的龋源性露髓恒牙,随访观察其临床疗效,为其应用于临床提供一定的理论指导。方法 收集龋源性露髓且牙根发育完成的患牙63例,其中行活髓切断术组为实验组（30例）,行根管治疗术组为对照组（33例）,术后分别于3、6、12、24个月进行复诊,通过临床评估及影像学评估来评价治疗效果,并进行比较,采用SPSS 18.0软件进行统计分析。 结果 观察3、6、12、24个月,活髓切断术组的成功率分别为100%、 96.67%、96.67%、93.33%,根管治疗术组的成功率分别为100%、100%、96.97%、96.97%,两组成功率无统计学差异（χ2=0.010, P=0.601）。 结论 活髓切断术可以应用于龋源性露髓的成熟恒牙并取得较高的成功率,是除根管治疗术以外可供选择的另一种较好的治疗方法。     

年轻恒前牙冠折活髓切断术的临床及组织学研究

目的通过临床和组织病理学研究探讨年轻恒前牙活髓切断术的愈后。方法临床上观察11例露髓冠折的上颌年轻恒中切牙活髓切断术后的牙根形成情况，牙根形成后，行根管治疗术，并对取出的根髓进行常规组织学研究，观察其病理变化。结果所有病例牙根均正常形成，根髓的组织学表现为与正常牙髓相比，出现根髓的退行性变，即成纤维细胞减少，胶原纤维增多，且有的牙髓出现玻璃样变性、钙变和细胞间质的颗粒样变性。结论活髓切断术是年轻恒前牙露髓冠折的首选治疗方法，但在牙根形成后，根髓会出现退行性变，因此，需及时改做根管治疗，为进一步的永久修复做准备。