PubMed · 284462
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M Scholzen. 1978. [Working with cements].. https://pubmed.ncbi.nlm.nih.gov/284462/
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The purpose of this study was to evaluate the capacity of penetration of four endodontic sealers (Endo Fill, Sealapex, AH Plus and Pulp Canal Sealer) into dentinal tubules. Seventy-two extracted human maxillary anterior teeth were utilized in this study. The teeth were cleaned and shaped by means of the balanced-forces technique. The work length was established at 1 mm beyond the apex. Copious irrigation with 10 ml of 5.25% sodium hypochlorite was carried out. The teeth were divided in 8 groups - 4 had the smear layer maintained, and 4 had it removed. The smear layer was removed with a commercial solution of 17% EDTA, and the root canal system was flushed for 3 min. Finally, the roots were irrigated with 3 ml of 5.25% sodium hypochlorite. All teeth were sealed by means of the technique of the condensation wave with a medium nonstandardized cone. After filling, the roots were grooved, longitudinally split and examined under a scanning electron microscope (SEM). The focus of observation was the interface between the dentin and the sealing material. The Rickert sealer (Pulp Canal) presented the maximum penetration depths into the dentinal tubules, and Sealapex, the minimum. The Spearman test was used to determine whether there were significant differences between the groups. The removal of smear layer allowed significant penetration of the sealers (p <= 0.01).
BACKGROUND: Bonding of orthodontic brackets to teeth is important to enable effective and efficient treatment with fixed appliances. The problem is bracket failure during treatment which increases operator chairside time and lengthens treatment time. A prolonged treatment is likely to increase the oral health risks of orthodontic treatment with fixed appliances one of which is irreversible enamel decalcification. OBJECTIVES: To evaluate the effectiveness of different orthodontic adhesives for bonding. SEARCH STRATEGY: Electronic databases: the Cochrane Oral Health Group's Trials Register, the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE and EMBASE. Date of most recent searches: August 2002 (CENTRAL) (The Cochrane Library Issue 2, 2002). SELECTION CRITERIA: Trials were selected if they met the following criteria: randomised controlled trials (RCTs) and controlled clinical trials (CCTs) comparing two different adhesive groups. Participants were patients with fixed orthodontic appliances. The interventions were adhesives that bonded stainless steel brackets to all teeth except the molars. The primary outcome was debond or bracket failure. DATA COLLECTION AND ANALYSIS: Data were recorded on decalcification as a secondary outcome, if present. Information regarding methods, participants, interventions, outcome measures and results were extracted in duplicate by pairs of reviewers (Nicky Mandall (NM) and Rye Mattick (CRM); Declan Millett (DTM) and Joy Hickman (JH2)). Since the data were not presented in a form that was amenable to meta-analysis, the results of the review are presented in narrative form only. MAIN RESULTS: Three trials satisfied the inclusion criteria. A chemical cured composite was compared with a light cure composite (one trial), a conventional glass ionomer cement (one trial) and a polyacid-modified resin composite (compomer) (one trial). The quality of the trial reports was generally poor. REVIEWER'S CONCLUSIONS: It is difficult to draw any conclusions from this review, however, suggestions are made for methods of improving future research involving orthodontic adhesives.
A modified silicate cement has previously been developed as a dental retrograde filling; it has great sealing ability, good biocompatibility, and anti-bacterial properties. However, its clinical application is limited by a long setting time and poor handling property. In the present study, the setting time has been shortened by raising the preparation temperature of the cement and adding transition elements into the partial-stabilized cement (PSC) to increase the rate of hydration reaction of the cement. The rate of the hydration was evaluated by micro-hardness measurement. Phase transformation and micro-structure were examined by an X-ray diffractometer and a scanning electron microscope, respectively.When the preparation temperature increased (1400 degrees C), the phase content of Ca(2)SiO(5)(C(2)S) and Ca(3)SiO(6)(C(3)S) increased but the CaO decreased. The setting time was shortened and the micro-hardness increased because the increased amplitude of vibration of the atoms about their equilibrium resting positions increased by increasing the heating temperature. When the transition elements were added to PSC, crystal defects were effectively created and monoclinic structure of C(3)S was favored to form, which would increase the hydrated reaction of PSC and shorten the setting time. Co addition is the most effective due to its ability to create more defects and stabilize the monoclinic structure. The micro-hardness of the PSC with Co 5 wt% addition was about 66 in the Vickers scale. It also exhibited an early setting within 20 min. We believe that the modified PSC will have a great potential in its application to perforation repair and retrograde filling in endodontic surgery.