Department of Pediatric Dentistry and Clinical Genetics, Faculty of Health Sciences, School of Dentistry, University of Copenhagen, Copenhagen, Denmark.
Dent Traumatol. 2012 Oct;28(5):379-85. doi: 10.1111/j.1600-9657.2011.01100.x. Epub 2012 Jan 11.
To analyze the influence of a crown fracture without pulp exposure on the risk of pulp necrosis (PN) in teeth with extrusion or lateral luxation.
The study included 82 permanent incisors with extrusion from 78 patients (57 male, 21 female) and 179 permanent incisors with lateral luxation from 149 patients (87 male, 62 female). A total of 25 teeth with extrusion and 33 teeth with lateral luxation had suffered a concomitant crown fracture (infraction, enamel fracture or enamel-dentin-fracture). All the teeth were examined and treated according to a standardized protocol.
The risk of PN was analyzed separately for teeth with immature and mature root development by the Kaplan-Meier method, the log-rank test and Cox regression (lateral luxation only). The level of significance was set at 5%. Risk factors included in the analysis were gender, age, crown fracture, and response to electric pulp test at the initial examination.
A concomitant crown fracture significantly increased the risk of PN in teeth with lateral luxation. For teeth with immature root development (hazard ratio: 10 [95% confidence interval (CI): 1.1-100] P = 0.04), the overall risk increased from 4.7% (95% CI: 0-10.8) to 40% (95% CI: 2.8-77.2). For teeth with mature root development [hazard ratio: 2.4 (95% CI: 1.4-4.2) P < 0.001], the overall risk increased from 65.1% (95% CI: 55.2-75.1) to 93% (95% CI: 85.5-100). In teeth with extrusion and mature root development, the overall risk of PN increased from 56.5% (95% CI: 37.7-75.4) to 76.5% (95% CI: 58.9-94) in case of a concomitant crown fracture, but the difference was not statistically significant (P > 0.05).
A concomitant crown fracture without pulp exposure significantly increased the risk of PN in teeth with lateral luxation. This risk factor may be used to identify teeth at increased risk of PN following lateral luxation injury.
分析无露髓的冠折对挤压或侧向脱位恒牙发生牙髓坏死（PN）的风险的影响。
本研究纳入了 78 名患者（男 57 例，女 21 例）的 82 颗挤压性恒切牙和 149 名患者（男 87 例，女 62 例）的 179 颗侧向脱位恒切牙。共有 25 颗挤压性和 33 颗侧向脱位性恒牙伴有并发冠折（不全折断、釉质折断或釉质-牙本质折断）。所有牙齿均按照标准化方案进行检查和治疗。
采用 Kaplan-Meier 法、对数秩检验和 Cox 回归（仅侧向脱位）分别分析未成熟和成熟根发育恒牙的 PN 风险，检验水准设为 5%。分析中纳入的危险因素包括性别、年龄、冠折和初始电活力测试反应。
并发冠折显著增加了侧向脱位恒牙发生 PN 的风险。对于未成熟根发育的恒牙（风险比：10 [95%置信区间（CI）：1.1-100] P = 0.04），总体风险从 4.7%（95%CI：0-10.8）增加至 40%（95%CI：2.8-77.2）。对于成熟根发育的恒牙（风险比：2.4 [95%CI：1.4-4.2] P < 0.001），总体风险从 65.1%（95%CI：55.2-75.1）增加至 93%（95%CI：85.5-100）。对于挤压性和成熟根发育的恒牙，并发冠折后 PN 的总体风险从 56.5%（95%CI：37.7-75.4）增加至 76.5%（95%CI：58.9-94），但差异无统计学意义（P > 0.05）。
无露髓的冠折显著增加了侧向脱位恒牙发生 PN 的风险。该危险因素可用于识别侧向脱位伤后发生 PN 风险增加的牙齿。
