Is there an association between crown discoloration and pulp necrosis in traumatized permanent teeth? A meta-analysis

Abstract The present study aimed to identify the scientific evidence regarding the association between crown discoloration and pulp necrosis in traumatized permanent teeth. A systematic literature search was conducted in the PubMed/Medline, Lilacs/BBO, Scopus, Web of Science, Cochrane Library databases, and grey literature. Quality assessment and bias control were carried out according to the Fowkes and Fulton guidelines. Meta-analysis was performed, and the odds ratio was calculated with a 95% confidence interval. The quality assessment of the evidence was determined for the meta-analysis outcomes using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach. From 2,702 studies identified, five articles met the inclusion criteria. One among these showed no methodological soundness and was excluded from the meta-analysis, and the remaining four studies were included in the meta-analysis. The total number of traumatized permanent teeth evaluated in the meta-analysis was 367. The results showed a positive association between crown discoloration and pulp necrosis in permanent teeth. Teeth with crown discoloration showed 23 times more chance to present pulp necrosis than teeth without crown discoloration (OR 23.82 [1.25, 452.87]; p = 0.03), with a very low certainty of evidence. There is a significant association between crown discoloration and pulp necrosis of traumatized permanent teeth. Due to the very low strength of evidence according to GRADE, this result should be viewed with caution.

摘要 本研究旨在明确外伤恒牙冠部变色与牙髓坏死之间关联的科学证据。研究系统检索了PubMed/Medline、Lilacs/BBO、Scopus、Web of Science、Cochrane Library数据库及灰色文献，并依据Fowkes与Fulton指南开展质量评价与偏倚控制。随后进行Meta分析，计算比值比（odds ratio, OR）及95%置信区间；同时采用推荐分级、评估、发展与评价（Grading of Recommendations Assessment, Development and Evaluation, GRADE）方法，对Meta分析结果的证据质量进行分级。初检共获得2702篇文献，其中5篇符合纳入标准。其中1篇研究方法学严谨性不足，被排除出本次Meta分析，剩余4项研究纳入分析。本次Meta分析共评估367颗外伤恒牙。结果显示，恒牙冠部变色与牙髓坏死呈正相关：冠部变色的恒牙发生牙髓坏死的风险为无冠部变色恒牙的23.82倍（OR=23.82，95%置信区间[1.25, 452.87]，p=0.03），但证据质量极低。综上，外伤恒牙冠部变色与牙髓坏死存在显著关联；鉴于GRADE分级显示证据强度极低，解读该结果时需谨慎。