Expression of matrix metalloproteinases 2 and 9 in replanted teeth with external root resorption: A cross-sectional study.

OBJECTIVE: To evaluate matrix metalloproteinase (MMP) expression in replanted permanent teeth with external root resorption (ERR). DESIGN: The present cross-sectional study included 42 patients with replanted permanent teeth, presenting with progressive forms of ERR, and referred for extraction according to the rehabilitation treatment plan or due to root fractures. The control group consisted of 12 healthy premolars, from 5 patients with good periodontal health and no radiographic evidence of root resorption, referred for extraction for orthodontic reasons. Root fragments were processed soon after extraction, and the supernatant was collected to measure matrix metalloproteinase 2/tissue inhibitor of metalloproteinase 2 (MMP-2/TIMP-2) and matrix metalloproteinase 9/tissue inhibitor of metalloproteinases 2 (MMP-9/TIMP-2) complexes through a double-ligand enzyme-linked immunosorbent assay (ELISA). RESULTS: Case groups with external inflammatory root resorption (EIRR) or external replacement root resorption (ERRR) showed significantly higher levels of MMP-2/TIMP-2 and MMP-9/TIMP-2 complexes than the control group. Additionally, comparisons between the case groups demonstrated that the MMP-2/TIMP-2 complex also had significantly higher levels in the ERRR group (p < 0.001). CONCLUSIONS: Our results suggest that MMP-2 and MMP-9 participate in the pathobiology of both types of ERR. In addition, the higher levels of MMP-2/TIMP-2 complex in the ERRR group support common modulation mechanisms with physiological bone turnover.

Pulp healing in immature replanted permanent teeth: A competing risk analysis.

BACKGROUND/AIM: Tooth displacement during avulsion causes total rupture of the pulp's neurovascular supply. Revascularization and pulp healing may occur in immature teeth, which gives rise to the recommendation that root canal treatment may not be required. The aim of this study was to evaluate the prognostic factors for the pulp's response after replantation of young permanent teeth. METHODS: Records from 117 patients with 133 replanted permanent immature teeth were reviewed, and pulp outcomes were classified as healing (hard tissue deposition on the dentinal walls followed by narrowing of the pulp lumen or ingrowth of bone-like tissue inside the pulp canal) or non-healing (pulp necrosis with infection). The effect of clinical and demographic co-variates on the hazards of both outcomes was assessed performing a competing risk model. RESULTS: Pulp necrosis with infection was diagnosed in 78.2% of the teeth, and healing was observed in 12.8% of the teeth. A total of 12 teeth (9.0%) were censored due to prophylactic removal of the pulp or severe external root resorption caused by eruption of adjacent canines. The cs-Cox model demonstrated that the hazards of pulp healing increased in teeth with extra-alveolar periods <15 min (csHR: 7.83, 95% CI 1.76-34.80, p = .01), while the hazards of pulp necrosis with infection decreased (csHR: 0.31, 95% CI: 0.10-0.92, p = .04). Teeth replanted with Moorrees' stages 4 and 5 of root development had higher hazards of pulp necrosis with infection than teeth with stage 2 of root development (csHR: 2.23, 95% CI 1.11-4.50, p = .03; csHR: 2.89, 95% CI: 1.40-5.95; p = .01). CONCLUSIONS: Pulp healing rarely occurred after replantation of young permanent teeth being associated with short extra-alveolar periods <15 min. Early stages of root development decreased the hazards of pulp necrosis with infection.

Survival of Replanted Permanent Teeth after Traumatic Avulsion.

INTRODUCTION: Tooth replantation is the treatment of choice for avulsion, even though its long-term prognosis shows great variability and few studies have adopted survival analysis to evaluate the fate of such teeth. The present study aimed to evaluate both the survival rate of replanted permanent teeth after traumatic avulsion as well as its clinical and demographic determinants. METHODS: Records from 576 patients treated at the Dental Trauma Clinic at the Federal University of Minas Gerais, Brazil, were analyzed to collect clinical and radiographic data. Kaplan-Meier curves and a multivariate Cox regression model were used to estimate the probability of replanted teeth remaining functional in the mouth and to determine prognostic factors. RESULTS: The post-replantation survival rate was 50% after 5.5 years. Immature teeth presented an increase of 51.3% in the loss rate (P = .002). Each additional year in the patient's age at the time of trauma, up to the limit of 16 years, reduced the loss rate of replanted teeth by 15% (P < .001). The storage of the avulsed teeth in milk decreased the loss rate of replanted teeth by 56.4% (P = .015) when compared with those kept dry. CONCLUSIONS: The overall survival rate after replantation of permanent teeeth was 50% after 5.5 years. Advanced stages of root development, together with the increase in the patient's age at the moment of trauma, up to the limit of 16 years, were good prognostic factors for tooth survival. The storage of avulsed teeth in milk was also associated with enhanced tooth survival after replantation.