Pediatric & Preventive Dentistry, Centre for Dental Education and Research, All India Institute of Medical Sciences, New Delhi, India.
Electron Microscope Facility, SAIF, Department of Anatomy, All India Institute of Medical Sciences, New Delhi, India.
Dent Traumatol. 2023 Apr;39(2):157-164. doi: 10.1111/edt.12807. Epub 2022 Nov 21.
Fragment reattachment is the recommended treatment modality in uncomplicated crown fractures. There is a paucity of literature regarding the mechanisms responsible for increased resistance to fracture after fragment rehydration in such cases. Hence, the aim of this proof-of-concept study was to decipher the microscopic changes in the penetration characteristics of resin in tooth fragments after different rehydration protocols.
Sixty bovine incisors free of structural deformities were fractured as per a standard protocol and the fragments were stored in saline at 4°C. They were randomly allocated into three groups (n = 20)-Group 1: negative-control, no-rehydration, Group 2: rehydration by immersion in distilled water for 15 min, Group 3: rehydration by humidification for 15 min. They were subjected to the "experimental bonding protocol" using an eighth-generation bonding agent mixed with rhodamine-B dye. The samples were subjected to decalcification and sectioned into cubical blocks (2 × 2 × 2 mm ). They were embedded in paraffin wax, sectioned by an ultramicrotome and evaluated by using a confocal laser scanning microscope. The depths and width of the resin tags were assessed by image analysis software, and the number of tags was counted manually by blinded evaluators. Statistical analysis was done with Stata-14.
The depth of penetration of the resin tags was greatest in Group 2 (927.81 ± 280.38 μm) followed by Group 3 (902.03 ± 371.85 μm) and Group 1 (287.74 ± 124.80 μm). Similarly, the width of the penetrated resin tags was greatest in Group 2 (58.29 ± 21.15), followed by Group 3 (35.53 ± 22.15) and Group 1 (23.89 ± 6.88). The number of resin tags in the majority of the samples in Group 1 had less than 25 tags (65%), whereas there were more than 25 tags in Group 2 (70%) and Group 3 (75%). These differences were statistically significant (p < .05).
The resin penetration, as observed by the number of tags and their depth and width, was significantly affected by the rehydration of the fragments. The fragments rehydrated in the distilled water had greater penetration of resin tags than those rehydrated in a humidification chamber.
在无并发症的冠折中，推荐使用碎片再附着治疗。关于在这种情况下碎片再水合后骨折阻力增加的机制，文献很少。因此，本概念验证研究的目的是破译不同再水合方案后牙碎片中树脂渗透特性的微观变化。
60 颗无结构畸形的牛切牙按标准方案折断，碎片储存在 4°C 的盐水中。将它们随机分为三组（每组 20 个）-第 1 组：阴性对照，不进行再水化，第 2 组：用蒸馏水浸泡 15 分钟再水化，第 3 组：用加湿法再水化 15 分钟。使用混合有罗丹明 B 染料的第八代粘结剂对它们进行“实验粘结方案”处理。样品进行脱钙，切成立方块（2×2×2mm）。它们被嵌入石蜡中，通过超微切片机切片，并使用共聚焦激光扫描显微镜进行评估。使用图像分析软件评估树脂标签的深度和宽度，并用盲法评估者手动计数标签数量。使用 Stata-14 进行统计分析。
树脂标签的渗透深度最大的是第 2 组（927.81±280.38μm），其次是第 3 组（902.03±371.85μm）和第 1 组（287.74±124.80μm）。同样，穿透树脂标签的宽度最大的是第 2 组（58.29±21.15），其次是第 3 组（35.53±22.15）和第 1 组（23.89±6.88）。第 1 组中大多数样本的树脂标签数量少于 25 个（65%），而第 2 组（70%）和第 3 组（75%）中有超过 25 个标签。这些差异具有统计学意义（p<.05）。
通过标签数量及其深度和宽度观察到的树脂渗透，受碎片再水化的显著影响。在蒸馏水中再水化的碎片的树脂标签渗透深度大于在加湿室中再水化的碎片。
