Outcome of Er,Cr:YSGG laser-assisted treatment of teeth with apical periodontitis: a blind randomized clinical trial.

OBJECTIVE: As clinical studies conducted to explore the safety and efficacy of new procedures are considered an important focus in endodontic research, the aim of this controlled clinical study was to compare a laser-assisted endodontic treatment using an erbium, chromium:yttrium-scandium-gallium-garnet (Er,Cr:YSGG) laser and radial firing tips (RFT) versus the conventional use of 3% sodium hypochlorite and interim calcium hydroxide paste, in teeth with chronic apical periodontitis. METHODS: Forty-three single-rooted and premolar teeth were randomly assigned. In group 1, teeth were prepared and irrigated with 3% sodium hypochlorite and calcium hydroxide inter-appointment dressing was applied; in group 2 teeth were prepared with saline solution and irradiated with Er,Cr:YSGG laser using RFT2 (140 µs, 37.5 mJ, 20 Hz) and RFT3 (140 µs, 62.5 mJ, 20 Hz) at the first and second appointments, respectively, four times each, moving at 2 mm/sec(-1) from apical to coronal. The primary outcome measure was change in apical bone density at 12 months, using the periapical index (PAI) for blind radiographic assessment. RESULTS: Thirty teeth were examined and subjected to statistical analysis, 12 in the control group and 18 in the test group. There were two treatment failures in the control group that were not included for analysis; both groups exhibited statistically significant decreases in PAI scores. CONCLUSIONS: The present findings suggest that for single-rooted and premolar teeth, this laser-assisted protocol can achieve predictable endodontic outcomes, comparable to conventional strategies in 1 year of follow-up.

Behaviour of co-cultured human osteoclastic and osteoblastic cells exposed to endodontic sealers' extracts.

OBJECTIVES: Bone tissue is constantly being moulded and shaped by the coordinated action of bone-resorbing osteoclasts and bone-synthesizing osteoblasts. This study addresses the long-term effects of endodontic sealers' extracts (AH Plus™, GuttaFlow™, Tubliseal™, Sealapex™ and RealSeal™) on co-cultures of human osteoclastic and osteoblastic cells. METHODS: The sealers were mixed according to the manufacturer's instructions, freshly extracted with culture medium (1.3 cm(2)/ml; 24 h; 37 °C, 5% CO2/air) and diluted (1:20-1:2,500). Co-cultures of osteoclastic and osteoblastic cells, established from precursors present in human peripheral blood mononuclear cells and bone marrow cells, respectively, were exposed to the extracts for 21 days. Co-cultures were characterized for the osteoclastic and osteoblastic response. RESULTS: The sealers caused a dose-dependent decrease on TRAP and ALP activities, respectively, an osteoclastic and an osteoblastic marker. The resorbing ability of the osteoclastic cells and the expression of osteoclastic and osteoblastic genes were also decreased; in addition, the extracts affected several intracellular signalling pathways. Inhibition was higher during the two first weeks, followed by adaptive cell responses. Osteoblastic response was more sensitive to the extracts' toxicity and showed lower adaptive ability. SIGNIFICANCE: A correlation to the clinical situation cannot be predicted; however, the results suggest that the sealers' eluents might disrupt the highly regulated interaction between osteoblastic and osteoclastic cells, compromising the local bone metabolism. Also, the higher susceptibility of the osteoblastic response might be particularly relevant in the initial stages of the healing of periapical lesions, due to the significant role of the bone formation events.