Regenerative Endodontic Treatment of Necrotic Primary Molars with Missing Premolars: A Case Series.

The endodontic treatment of necrotic primary teeth with missing successors presents a unique clinical challenge. The purpose of this report was to describe the clinical and radiological outcomes of regenerative endodontic treatment (revascularization) of necrotic primary molars. Four infected necrotic primary second molars with missing premolars were treated with a two-visit revascularization protocol. The crowns were restored with amalgam or acid-etch composite resin. The teeth were followed-up clinically and radiographically for 18 months. At six months, all teeth demonstrated radiographic evidence of complete periradicular healing and positive response to cold test, and remained symptomless thereafter.

Effects of different irrigation regimens on the sealing properties of repaired furcal perforations.

OBJECTIVE: The pulp chamber is inevitably exposed to irrigants during endodontic therapy. This study aimed to investigate whether different irrigation regimens would alter the sealing ability of repaired furcal perforations. STUDY DESIGN: Pulp chambers of 90 extracted human molars were accessed, after which standardized diamond bur-cut perforations were created in the center of the pulp chamber floor. The canal orifices and the apical end of roots were sealed with acid-etch composite resin. Eighty teeth were randomly divided into 2 groups (n = 40/group) according to the material used for repairing the perforation defects: (1) Mineral trioxide aggregate (MTA), (2) Super-EBA. The remaining teeth (n = 10) served as controls. The specimens were further subgrouped according to the irrigation regimens applied over the repair site (n = 10/group): (a) 5.25% NaOCl, (b) 5.25% NaOCl + EDTA, (c) 5.25% NaOCl + MTAD, and (d) No irrigation. Coronal leakage was measured by the fluid-filtration method at 1 day and 1 week. RESULTS: Fluid conductance was not affected by the type of repair material (P = .964) or time (P = .726), but was affected significantly by the irrigation regimens in the following ranking: (P < .001): NaOCl < or = No Irrigation < NaOCl + MTAD < or = NaOCl + EDTA. CONCLUSION: The sealing ability of furcal perforations repaired with MTA or Super-EBA were differentially affected by exposure to the tested irrigation regimens.

The effect of EDTA, EGTA, EDTAC, and tetracycline-HCl with and without subsequent NaOCl treatment on the microhardness of root canal dentin.

OBJECTIVE: The purpose of this study was to evaluate the effect of single and combined use of ethylenediamine tetra acetic acid (EDTA), ethylene glycol bis [b-aminoethylether] N,N,N',N'-tetraacetic acid (EGTA), EDTA plus Cetavlon (EDTAC), tetracycline-HCl, and NaOCl on the microhardness of root canal dentin. STUDY DESIGN: The crowns of 30 single-rooted human teeth were discarded at the cementoenamel junction and the roots were bisected longitudinally to obtain root halves (N = 60). The specimens were embedded in autopolymerizing acrylic resin, leaving the root canal dentin exposed. Dentin surfaces were prepared for microhardness test by grinding and polishing. The reference microhardness values of untreated specimens were recorded using a Vicker's microhardness tester at the apical, midroot, and cervical levels of the root canal. Thereafter, the specimens treated with single (test solution only) or combined (test solution, followed by 2.5% NaOCl) versions of the irrigants for 5 minutes. Posttreatment microhardness values were obtained as with initial ones. Statistical comparisons between the test groups and among single and combined treatments were carried out using 2-way ANOVA with repeated measures (P =.05). Comparisons within each group with respect to application regions were made with Friedman's nonparametric 2-way analysis of variance at the same level of significance. RESULTS: All treatment regimens except distilled water significantly decreased the microhardness of the root canal dentin (P < . 05). The single and combined use of EDTA decreased the microhardness of the root canal dentin significantly more than all other treatment regimens (P < .05). Compared with their single-treatment versions, all combined treatment regimens decreased the mean microhardness values significantly (P < .05). A comparison of single and combined treatment regimens revealed significant decreases only for EDTA and EDTA + NaOCl in the coronal region and for EDTAC and EDTAC + NaOCl in the apical and middle regions of the root canal (P < .05). CONCLUSIONS: The use of EDTA alone or prior to NaOCl resulted in the maximum decrease in dentin microhardness. The softening effect of subsequent NaOCl treatment was both material and region dependent. However, for combined treatment regimens, subsequent use of NaOCl levels the statistical differences between the regional microhardness values obtained after treatment with EGTA, EDTAC, and tetracycline-HCl.

Calcium loss from root canal dentin following EDTA, EGTA, EDTAC, and tetracycline-HCl treatment with or without subsequent NaOCl irrigation.

The aim of this study was to determine the extent of calcium removal on root canal dentin after 17% EDTA, 17% EGTA, 15% EDTAC, and 1% tetracycline-HCl treatment; with or without subsequent use of 2.5% NaOCl. Extracted single-rooted human teeth were bisected longitudinally and the root halves (n=100) were isolated with nail varnish, leaving the root canal exposed. The samples were immersed in the test solutions for 1 and 5 minutes, after which the amount of calcium ion (Ca(2+)) release into the solutions was determined by flame photometry. Regardless of treatment time, all single (treatment solution only) and combined (treatment solution with subsequent NaOCl application) irrigation regimens removed significantly more Ca(2+) than control treatment (distilled water). Compared with other groups, treatment with 17% EDTA and 17% EDTA + 2.5% NaOCl resulted in the maximum amount of Ca(2+) removal from root canal dentin (p<0.05). All combined-treatment groups except 17% EGTA + 2.5% NaOCl removed significantly more Ca(2+) than their single-treatment versions (p<0.05). Within each test group, extending the treatment time to 5 minutes resulted in significantly more Ca(2+) removal (p<0.05).

Effect of mineral trioxide aggregate cements on transforming growth factor beta1 and bone morphogenetic protein production by human fibroblasts in vitro.

The aim of this study was to evaluate and compare the effects of two commercial mineral trioxide aggregate (MTA) cements (ProRoot MTA and MTA Angelus) on transforming growth factor (TGF)-beta1 and bone morphogenetic protein (BMP)-2 levels produced by cultured human gingival fibroblasts (HGFs). Human gingival tissues were obtained from individuals with healthy periodontium. HGFs were grown at 37 degrees C in humidified atmosphere of 5% CO(2) in Dulbecco's modified Eagle's medium, supplemented with 10% fetal calf serum, penicillin, and streptomycin. After 24 and 72 hours of exposure to the MTA products, HGF viability was determined by using 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl tetrazolium bromide assay. TGF-beta1 and BMP-2 levels in cell-free culture media were determined by enzyme-linked immunosorbent assay. Cell viability of the test groups was significantly lower than that of control at 24 and 72 hours (p < 0.05) but showed an increase at 72 hours (p < 0.05). Both test groups showed increased TGF beta-1 levels at 72 hours (p < 0.05), whereas the MTA Angelus group displayed higher TGF beta-1 levels than control and ProRoot MTA groups at 24 and 72 hours (p < 0.05). At 24 hours, BMP-2 levels of the ProRoot group were significantly higher than that of MTA Angelus (p < 0.05). Both test materials increased the BMP-2 levels within time (p < 0.05) and displayed similar levels at 72 hours (p > 0.05). These results suggest that both MTA products are capable of stimulating HGF to produce BMP-2, whereas the stimulatory effect for TGF beta-1 is material dependent.

Ultramorphological and histochemical changes after ER,CR:YSGG laser irradiation and two different irrigation regimes.

The purpose of this study was to evaluate the ultramorphological and chemical changes in Er,Cr:YSGG laser-treated radicular dentin in comparison with two different irrigation regimes. Extracted human premolars were assigned into three experimental groups. Group 1: After each file size, root canals were irrigated with 5.25% NaOCL, followed by a final irrigation with 5.25% NaOCL. Group 2: At each file size, biomechanical preparation was performed in conjunction with Rc-Prep, followed by 5.25% NaOCL irrigation; and 5.25% NaOCL for the final flush. Group 3: 5.25% NaOCL was used after each file size, followed by Er,Cr:YSGG laser irradiation; and a final flush with 5.25% NaOCL. Scanning electron microscopic (SEM) evaluations revealed failure of smear removal in NaOCL-irrigated specimens. RC-Prep + NaOCL-treated dentin revealed moderate-to-total presence of the smear layer with distinct areas of exposed collagen. Er,Cr:YSGG laser irradiation of radicular dentin also resulted in partial or total removal of the smear associated with a few small regions of thermal injury, including carbonization and partial melting. Energy dispersive X-ray analysis (SEM-EDX) showed no significant difference between the Ca/P ratios of the test groups, suggesting absence of changes at the molecular level.

Comparison of conventional, rotary, and ultrasonic preparation, different final irrigation regimens, and 2 sealers in primary molar root canal therapy.

PURPOSE: The aim of this study was to compare the shaping effectiveness rotary nickel-titanium (Profile .04 ISO), ultrasonic (K-Type/Satelec), and stainless-steel hand file (K-file/Maillefer) instrumentation and to assess tubular penetration of 2 gutta percha sealers (AH Plus and Sealite-Ultra) following 4 different final irrigation regimens in primary molar roots. METHODS: Distal roots of extracted human primary second molars were prepared with 1 of the 3 instrumentation techniques. Direct digital radiographs were obtained on a custom-made platform before and after instrumentations. The amount of dentin removal, canal transportation, centering of preparation, changes in root curvature and working length, and zip formation were evaluated using image analysis. RESULTS: While no significant differences were found between the 3 preparation techniques in regards to dentin removal (P > .05), ultrasonic instrumentation significantly increased the incidence of zip formation (P < .05) and decreased working length (P < .05). Following final irrigation with 2.5% sodium hypochlorite (NaOCL), 10% ethylenediaminetetraacetic acid (EDTA), 17% EDTA, or distilled water (control), tubular penetration of the tested sealers were investigated under scanning electron microscope. Use of AH Plus after 17% EDTA irrigation exhibited the best tubular penetration. CONCLUSIONS: Root canal preparation with Profile .04 ISO nickel titanium instruments can be a viable alternative to manual instrumentation in primary teeth. When used as a gutta percha sealer, AH Plus exhibits good tubular penetration when 17% EDTA is used for final flush.