The histological effects of four endodontic sealers implanted in the oral mucosa: submucous injection versus implant in polyethylene tubes.

AIM: The aim of this study was to evaluate pigmentation and tissue response to four endodontic sealers placed in the oral mucosa of rabbits by either submucous injection or implant in polyethylene tubes. METHODOLOGY: Thirty white New Zealand rabbits were divided randomly into two groups of eight for N-Rickert and AH-26, and two groups of seven for Fillcanal and Sealer 2 6. On the right side of the filter, corresponding to the gingivo-labial sulcus in humans, the sealer was injected; on the left side the sealer was placed within a polyethylene tube and implanted. Direct clinical observations were made at 30, 60 and 90 days. The animals were then sacrificed for histological analysis. RESULTS: After 60 days of observation N-Rickert and AH-26 produced tattoos that became larger by 90 days. Submucous injection produced larger and more numerous pigmentation, when compared to implant in polyethylene tubes. N-Rickert sealer displayed larger and more numerous tattoos when compared to AH-26. Histological analysis showed no differences between the two methods of implantation. All sealers elicited some kind of inflammatory response; the most irritant was Fillcanal, followed by N-Rickert and AH-26. Sealer 26 elicited a mild reaction only. CONCLUSIONS: Under the conditions of this study there was no relationship between the method of implantation and the tissue response; the silver-containing sealers produced pigmentation, and the concentration of silver influenced the quantity and size of the tattoos. The sealers elicited various responses when in direct contact with the surrounding tissues: the calcium hydroxide-containing sealer had enhanced healing when compared to the other sealers.

A comparative study of the pulp chamber preparation in maxillary canines.

The effectiveness of three methods of lingual dentin edge removal was evaluated in maxillary canines: Batt burs (group I), Gates-Glidden burs (group II) and manual reamers, Batt burs and Gates-Glidden burs (group III). The results showed better dentin edge removal and degree of conicity in group III.

Chemical analysis of the formation of calcium carbonate and its influence on calcium hydroxide pastes in connective tissue of the dog--Part II.

The objective of this research was to chemically analyze calcium hydroxide pastes added to three hydrosoluble vehicles having different acid-base characteristics by implanting polyethylene tubes in subcutaneous connective tissue in dogs, evaluating the formation of calcium carbonate over a period of 7, 30, 45, and 60 days. The three vehicles were saline, anesthetic, and polyethylene glycol 400. Determination of the formation of calcium carbonate was evaluated by volumetry of neutralization using hydrochloric acid for titration.

SEM analysis of smear layer removal after manual and automated handpiece root canal preparation.

Scanning electron microscopy was used to analyze the smear layer removal after root canal preparation by a manual technique and by an automated handpiece, the Canal Finder System (CFS). When 1% sodium hypochlorite was used as the irrigating solution, both manual and CFS techniques showed root canal walls with a dense smear layer obscuring the dentinal tubules entrance plus a large amount of debris. Root canal walls of the group of teeth treated with a chelating agent (EDTA) for 5 min and a final flush, after the preparation, with 1% sodium hypochlorite as an irrigating solution showed the cervical, middle and apical thirds extremely smooth and clear.

Chemical analysis of the liberation of calcium and hydroxyl ions from calcium hydroxide pastes in connective tissue in the dog--Part I.

The objective of this research is to chemically analyze calcium hydroxide pastes added to three hydrosoluble vehicles having different acid-base characteristics using polyethylene tubes implanted in subcutaneous connective tissue in a dog, evaluating the liberation of calcium and hydroxyl ions over a period of 7, 30, 45 and 60 days. The three vehicles were saline, anesthetic, and polyethylene glycol 400. Chemical analysis of the liberated calcium ions was done by means of conductimetry using EDTA for titration. Liberation of hydroxyl ions was determined by analogy of calcium ions liberated, which are in direct proportion to the molecular weight of calcium hydroxide.

A clinical evaluation of 2% buffered glutaraldehyde in pulpotomies of human deciduous teeth: a 24-month study.

The purpose of this study is to evaluate the clinical results obtained with the use of glutaraldehyde in pulpotomies performed on deciduous teeth, in a recall of 24 months. Our results showed a success greater than 90%, similar to other clinical studies.

Dentinal diffusion of hydroxyl ions of various calcium hydroxide pastes.

The aim of this study was to analyze in vitro the dentinal diffusion of hydroxyl ions of calcium hydroxide pastes, prepared with different acid-base vehicles, in an inert nitrogen atmosphere. Sixty maxillary incisors with mature apexes were selected and after access and root canal preparation each root was filled with calcium hydroxide pastes prepared with different vehicles: saline solution, anesthetic and polyethylene glycol 400. The roots were then sectioned 2 mm from the apical vertex and the teeth mounted in the center of a round platform, filled with saline solution up to 2 mm from the root tip. The platforms remained inert in an atmosphere of nitrogen, completely sealed, in the absence of light and with a constant temperature of 36.5 degrees C. Diffusion analysis of the hydroxyl ions was carried out by a colorimetric method on days 7, 15, 30, 45 and 60. Calcium hydroxide pastes prepared with saline solution and anesthetic showed a pH change of 5-7 to 7-8 after 30 days, remaining at this level at 60 days. In the polyethylene glycol 400 group, the same alteration occurred at 45 days, and continued at 60 days.

The choice of the master cone: a comparative study.

The aim of this study was to evaluate the choice of the gutta-percha master cone during root canal filling. A total of 258 root canals were instrumented according to standard techniques and master cones were selected. The root canals were divided into two groups: group I, in which the master cone was of the same number as the instrument used for apical preparation without any additional operative procedure, and group II in which the master cone did not correspond in number or if additional operative procedures were performed. Group I consisted of 162 root canals and group II consisted of only 96, a larger but not statistically significant result.

Quality analysis of the root canal filling employing gutta-percha thermoplasticized at a low temperature (Ultrafil system).

The objective of this study was the investigation of the sealing properties of gutta-percha thermoplasticized at a low temperature by either employing or not N-Rickert cement and vertical condensation. Methylene blue at 0.5% was used to demonstrate the apical leakage. Results demonstrated that minor penetration indexes were attained when cement was not employed and vertical condensation was accomplished.

[Determination of the apical limits of instrumentation by subtraction using the paralleling radiographic technic. (Study contribution)]. / Determinação do limite apical de instrumentação por subtração através da técnica radiográfica do paralelismo. (Contribuição ao estudo).

The objective of the present work was verifying the apical position of the file when a technique based on subtraction and parallelism principle is used for determining the actual length of instrumentation. For this purpose, 24 natural teeth, in a total of 51 root canals, were used from patients under treatment in Endodontics Course of the Fundação para o Desenvolvimento Científico e Tecnológico da Odontologia. The teeth were previously radiographed with the parallelism technique. For each canal it was subtracted 3 mm in cases of vital pulp and 1.5 mm in necrotic form the length seen in X-ray. This measure was transferred to the endodontic instrument and with the file in the interior of the canal another X-ray was taken. The distance between the tip of the instrument and the root radiographic apex was measured. The results showed the presence of distortion in the original value with the greatest index to those teeth with necrotic pulp.