Adverse outcomes of dental trauma splinting as related to displacement injury and pulpal blood flow level.

Splinting of traumatically displaced permanent teeth has been described as an effective modality in the treatment of patients with dental injuries. The purpose of this study was to (i) investigate whether dental injury diagnosis may predict adverse outcomes occurring 96 weeks after splint removal, and (ii) evaluate whether the severity of adverse outcome is related to laser Doppler flowmetry (LDF) measurements of pulpal blood flow (PBF). In 206 trauma patients, 273 permanent maxillary incisors treated by repositioning and splinting, and the respective contralateral homologous control teeth were investigated clinically and radiographically, and by LDF to assess local PBF values. Dental displacement injuries were classified as grade I (subluxation), grade II (lateral or extrusive luxation) and grade III (avulsion or intrusive luxation). Outcomes were classified as 'absence of loss of sensitivity, periapical radiolucency, and/or grey discolouration of crown', type I (loss of sensitivity), type II (loss of sensitivity and periapical radiolucency or grey discoloration of crown) and type III (loss of sensitivity, periapical radiolucency and grey discoloration of crown). An adverse outcome was defined as the presence of 'periapical radiolucency and/or grey discoloration'. A multiple logistic regression analysis was used to compute the odds ratio (OR) for dental displacement injury for adverse outcome (n = 69) vs non-adverse outcome (n = 168). An ordinal stepwise regresssion was completed to assess the degree of association between PBF measurements and outcome groups. Significant increase in risk of an adverse outcome occurred with a grade II dental displacement injury (OR 14.3) (P = 0.000) and a grade III dental displacement injury (OR 19.9) (P = 0.000). PBF measurements that were significantly associated with more severe outcome were PBF levels of < or =3 perfusion units (PU) (OR 399.4) (P = 0.000), those of >3 PU and < or =6 PU (OR 100.5) (P = 0.000), and those of >6 PU and < or =9PU (OR 6.2) (P = 0.000). Diagnoses of displaced teeth predicted dental injury patients who went on to show adverse treatment outcomes of splinting. PBF measurements were related to the severity of adverse outcome.