Apical hard-tissue deposition in adult teeth of monkeys with use of calcium hydroxide

Alternative Antibiotics in Dentistry: Antimicrobial Peptides

The rise of antibiotic resistant bacteria due to overuse and misuse of antibiotics in medicine and dentistry is a growing concern. New approaches are needed to combat antibiotic resistant (AR) bacterial infections. There are a number of methods available and in development to address AR infections. Dentists conventionally use chemicals such as chlorohexidine and calcium hydroxide to kill oral bacteria, with many groups recently developing more biocompatible antimicrobial peptides (AMPs) for use in the oral cavity. AMPs are promising candidates in the treatment of (oral) infections. Also known as host defense peptides, AMPs have been isolated from animals across all kingdoms of life and play an integral role in the innate immunity of both prokaryotic and eukaryotic organisms by responding to pathogens. Despite progress over the last four decades, there are only a few AMPs approved for clinical use. This review summarizes an Introduction to Oral Microbiome and Oral Infections, Traditional Antibiotics and Alternatives & Antimicrobial Peptides. There is a focus on cationic AMP characteristics and mechanisms of actions, and an overview of animal-derived natural and synthetic AMPs, as well as observed microbial resistance.

The effect of maintaining apical patency on periapical extrusion

Thirty-three human maxillary incisors were secured in the openings of a glass vial. Root canals were instrumented to the apical constriction with a step-back technique and a patency file was not used throughout the root canal preparation. The irrigant, 1% NaOCl, was delivered by means of a plastic syringe with a 23-gauge needle and the overflow was suctioned with an aspirator. The total volume of irrigant used was 10 ml. Apically extruded debris and NaOCl were measured. The apical constriction was then deliberately enlarged. With a step-back technique a new 'apical constriction' was created, coronally to the original one. A patency file was again not used, and irrigation was identical to the that used during the initial root canal preparation. Extruded debris and NaOCl in each bottle were again measured. Results indicated that there was significant difference in the amounts of extruded material before and after the enlargement of the apical constriction with greater extrusion when the constriction remained intact.

Structure and chemical composition of an experimentally formed apical barrier after the application of calcium-glycerophosphate

Transformation in the structure and composition of calcium-glycerophosphate (Ca-GP) was investigated using a scanning electron microscope fitted with an energy dispersive X-ray microanalysis (EDX) system. Ca-GP was packed inside roots that were subsequently implanted into the mandibles of rats to stimulate the formation of an apical barrier. Scanning electron microscopic observations of packed Ca-GP revealed three types of structures: globular aggregates, plate or flake-like aggregates, and granular aggregates. The average Ca/P molar ratios of EDX by area mode--postoperatively obtained at days 1, 3, 5, and 7--were 1.300, 1.533, 1.472, and 1.495 (analytic area: 0.01 to 0.03 mm2) and those of EDX by point mode were 1.220, 1.451, 1.487, and 1.467 (analytic point: 0.05 micron 2). The magnesium (Mg) weight percentage was found to be approximately 1.9 at days 3, 5, and 7, similar to Mg-substituted whitlockite. These findings suggest that Ca-GP are transformed, over a period of 3 days into Mg-substituted whitlockite as a result of being hydrolyzed by tissue fluid.

Reaction of dogs' teeth to root canal filling with mineral trioxide aggregate or a glass ionomer sealer

This study was conducted to observe the reaction of apical tissues of dogs' teeth after root canal filling with gutta-percha and mineral trioxide aggregate (MTA) or a glass ionomer (Ketac-Endo) as a sealer. The root canals were instrumented and filled by the lateral condensation technique with the sealers studied. Animals were killed 6 months later, and the specimens were removed and prepared for histological analysis. Results showed no inflammatory reaction of apical tissue and total closure of the apical foramen of all the teeth sealed with MTA. The teeth sealed with Ketac-Endo showed two cases of partial closure and different degrees of chronic inflammatory reaction. In conclusion, MTA exhibited better biological properties than Ketac-Endo.

Periapical repair and apical closure of a pulpless tooth using calcium hydroxide

A case with a wide-open apex and a large cystlike periapical lesion in an adult is presented. The lesion formed as a result of necrosis from trauma to a maxillary central incisor 12 years ago. After nonsurgical endodontic treatment with calcium hydroxide paste and a calcium hydroxide-containing root canal sealer, apical closure and significant healing of the periapical lesion within 15 months were observed. This report suggests that even large periapical lesions (likely cystic) could respond favorably to nonsurgical treatment.

A clinical evaluation of one and two-appointment root canal therapy using calcium hydroxide

A clinical study using vital maxillary central incisors was performed to evaluate the incidence of postoperative pain after root canal treatment in one- or two-appointments using a calcium hydroxide-containing root canal sealer. No differences were observed between the two groups.

Apical closure of mature molar roots with the use of calcium hydroxide

Calcium hydroxide may induce apical root closure in affected mature teeth as well as in immature teeth. Once an apical hard tissue barrier is formed, a permanent root canal filling can be safely condensed. Two cases are described in which calcium hydroxide induced apical root closure in mature molar teeth where the apical constriction was lost because of chronic inflammatory process.

The effect of newly developed root canal sealers on rat dental pulp cells in primary culture

Cytotoxicity was compared between new root canal sealers (New A, New B, and New B-2) and conventional root canal sealers (AH26, Diaket, Canals, Tubi-Seal, and Sealapex). Dental pulp cells of rats, obtained through primary cell culture, were used. In the experiments with the freshly prepared sealers, the incorporation of [3H]thymidine into cellular DNA was analyzed. In the experiments with the set sealers, the morphological changes of cells were microscopically examined. In the experiments with the fresh sealers, AH26 and Diaket showed strong inhibitive effects on the DNA synthesis, whereas no such effects were noted with the new sealers and Sealapex. On the other hand, in the experiments with the set sealers, the new sealers and Diaket exerted little influence on the cells. However, other sealers had considerable toxicity. These results suggest that the new sealers were the least toxic in vitro, compared with five conventional sealers.