Background: It has been suggested that fissures of the occlusal surface of equine cheek teeth may develop into crown fractures.

Objectives: To examine the evolution of fissures present on the occlusal surface of cheek teeth. Furthermore, to investigate the presence of a fissure as a risk factor for the development of a subsequent crown fracture.

Study Design: Observational longitudinal study.

Methods: Bi-annual dental examinations were performed on 36 horses for 3 years. Video-recordings were made to evaluate the evolution of detected fissures. The effect of possible predictors on the development of tooth fractures was investigated by regression analysis.

Results: The evolution of 785 fissures (467 type 1a, 271 type 1b, 47 type 2) was recorded. Fissure characteristics were observed to remain unchanged, disappear, become longer, shorter, change in configuration or change in color. Partial crown fractures (22 maxillary, 50 mandibular) were recorded in 52 cheek teeth in 22/36 horses. Fifty-nine of these fractures evolved from previously observed fissures (24 type 1a, 29 type 1b, 6 type 2). All fissure types proved to be a significant risk factor for the development of a crown fracture (p < 0.001), with the highest odds for type 2 fissures (OR = 14.27; 95% CI = 4.88–41.71). Other significant risk factors were the time of follow-up (p < 0.001), mandibular teeth (p < 0.001) and the lingual side of a tooth (p < 0.001). All fractures were non-complicated.

Main Limitations: Some horses were prematurely lost for follow-up, which perhaps influenced the results. A longer follow-up period would have also allowed an evaluation of the risk for pulp disease on the long term subsequent to partial crown fractures.

Conclusions: The presence of a fissure of any type, mandibular cheek teeth, the lingual side of cheek teeth, and time of follow-up proved to be significant risk factors for development of a cheek tooth crown fracture. Type 2 fissures showed the highest odds followed by type 1b fissures. The observed partial crown fractures demonstrated a low clinical impact whereby no tooth showed signs of development of endodontal disease.

背景： 已经表明马脸颊牙齿的咬合面裂痕可能发展为冠状骨折。

目标：检查脸颊牙合面裂痕的演变。此外，调查裂隙的存在是导致随后的冠状骨折发展的危险因素。

学习规划： 观察性纵向研究。

方法：每三年对36匹马进行一次牙齿检查，为期3年。进行录像以评估检测到的裂缝的演变。通过回归分析研究了可能的预测因素对牙齿发育的影响。

结果：记录了785个裂缝的演化（467型1a，271型1b，47型2）。观察到裂隙特征保持不变，消失，变长，变短，构型变化或颜色变化。在22/36匹马的52个脸颊牙齿中记录了局部冠骨折（上颌22个，下颌50个）。这些裂缝中有59处是由先前观察到的裂缝演化而来的（24型1a，29型1b，6型2）。事实证明，所有裂缝类型都是造成冠状骨折的重要危险因素（p <0.001），且2型裂缝的赔率最高（要么= 14.27; 95％CI = 4.88–41.71）。其他重大危险因素是随访时间（p <0.001），下颌牙齿（p <0.001）和牙齿的舌侧（p<0.001）。所有骨折均无并发症。

主要局限性：一些马匹因过早失踪而无法跟进，这可能会影响结果。较长的随访时间也可以评估冠冠部分骨折后长期发生牙髓疾病的风险。

结论：任何类型的裂痕，下颌颊齿，颊齿舌侧以及随访时间的存在均被证明是发生颊齿冠骨折的重要危险因素。2型裂缝显示最高几率，其次是1b型裂缝。观察到的部分冠状骨折显示出较低的临床影响，因此没有牙齿显示出牙髓疾病的迹象。