Prognosis of Traumatized Permanent Teeth Affected by Multiple Injuries (Combination Injuries): A Systematic Review and Meta-Analysis.

BACKGROUND/AIMS: The prognosis of traumatic dental injuries (TDI) of permanent teeth depends on several factors related to the injury, patient characteristics, management, and follow-up protocols. When such injuries affect both hard dental tissues and the periodontium ("combination injuries"), the risk of adverse healing complications increases. However, a significant knowledge gap exists regarding the factors associated with their etiopathogenesis. Therefore, this systematic review aimed to evaluate the prognosis of traumatized permanent teeth affected by combination injuries.

METHODS

An a priori protocol was registered in PROSPERO. A search strategy based on the research question was prepared, and the search was performed on PubMed, EMBASE, Web of Science, and Scopus on December 4, 2026. An additional grey literature search and reference search were also performed. Clinical studies reporting outcomes of permanent teeth with combination injuries and a follow-up greater than six months were included. Data extraction, risk of bias assessment, and meta-analysis were performed. The certainty of evidence was evaluated using GRADE.

RESULTS

The electronic search of databases revealed 8190 records. Titles and abstracts of 4445 of them were evaluated, resulting in 177 studies for full-text screening. Finally, 10 of them could qualify for inclusion in the systematic review, and one more study was identified from reference searching. The incidence of pulp necrosis was high, with a pooled incidence of 42% (95% CI: 33%-52%, I2 = 87%) in teeth with crown fracture and luxation and 33% (95% CI: 26%-41%, I2 = 16.2%) in teeth with the combination of uncomplicated crown fracture and subluxation. Teeth with mature root development had a significantly higher risk of pulp necrosis (risk ratio = 1.70; 95% CI: 1.15-2.48). Other complications were less frequently reported. The overall certainty of evidence was very low.

CONCLUSIONS

The pooled incidence of pulp necrosis among permanent teeth with combination injuries was 39%. Greater severity of luxation injury in any combination and mature status of the root showed a significantly higher risk of pulp necrosis and healing complications. The evidence base for the prognosis of combination injuries showed very low certainty, indicating the need for future studies addressing the limitations observed in the review.