Mauro Juvenal Nery

Reaction of rat connective tissue to implanted dentin tubes filled with mineral trioxide aggregate or calcium hydroxide

This study was conducted to observe the rat subcutaneous connective tissue reaction to the implanted dentin tubes filled with calcium hydroxide or mineral trioxide aggregate. The animals were sacrificed after 7 and 30 days, and the specimens were prepared for morphological study. Some undecalcified specimens were prepared for histological analysis with polarized light and Von Kossa technique for calcium. The results were similar for both studied materials. At the tube openings, there were Von Kossa-positive granules that were birefringent to polarized light. Next to these granulations, there was an irregular tissue like a bridge that was Von Kossa-positive. The dentin walls of the tubes exhibited in the tubules a structure highly birefringent to polarized light, usually like a layer and at different depths. It is possible that the mechanism of action of both materials has some similarity.

Reaction of human periapical tissue to pulp extirpation and immediate root canal filling with calcium hydroxide

The purpose of this study was to carry out a histologic investigation of apical human teeth after vital pulp extirpation and immediate root canal filling with calcium hydroxide. The findings showed that the healing process of human apical tissues in teeth filled with calcium hydroxide was similar to the pulp healing process when the same material is used, and that calcium hydroxide as a root canal filling material induced apical closure by hard-tissue deposition.

Rat tissue reaction to MTA FILLAPEX

The aim of this study was to evaluate the rat subcutaneous tissue reaction to implanted polyethylene tubes filled with mineral trioxide aggregate (MTA) FILLAPEX® compared to the reaction to tubes filled with Sealapex® or Angelus MTA® . These materials were placed in polyethylene tubes and implanted into the dorsal connective tissue of Wistar rats for 7, 15, 30, 60, and 90 days. The specimens were stained with hematoxylin and eosin or Von Kossa or left unstained for examination under polarized light. Qualitative and quantitative evaluations of the reaction were performed. All materials caused moderate reactions after 7 days, which decreased with time. The reactions were moderate and similar to that evoked by the control and Sealapex® on the 15th day. MTA FILLAPEX(®) and Angelus MTA caused mild reactions beginning after 15 days. Mineralization and granulation birefringent to polarized light were observed with all materials. It was concluded that MTA FILLAPEX® was biocompatible and stimulated mineralization.

Root canal treatment with calcium hydroxide

Root canals of dog premolar teeth were negotiated and overfilled with calcium hydroxide paste. After 30 days, half of the treated teeth were refilled up to the apical limit. Root canals not filled were considered as the control group. Ninety days after the first treatment, histologic analysis showed more favorable results in the refilled root canals. The overfilling elicits calcium hydroxide resorption and the ingrowth of periapical connective tissue into the root canal.

Sealability of MTA and calcium hydroxidecontaining sealers

Objectives The aim of this study was to evaluate the apical sealability of Fillapex®, Endo-CPM-Sealer® and Sealapex®. Material and Methods Ninety-four freshly extracted single-rooted teeth were selected and decoronated. All teeth were radiographed to confirm the existence of a single and straight root canal, which was prepared using Protaper Universal and 2.5% sodium hypochlorite. The teeth were randomly divided in groups of 10 specimens each according to the sealer, and the canals were filled using the single cone technique and one of the sealers. Four additional teeth were used as controls. The teeth were submitted to dye leakage with Rhodamine B for 24 h but using vacuum on the initial 15 min. Thereafter, they were cut longitudinally and the leakage was measured in a linear fashion from apex to crown. Data were analyzed by ANOVA and Tukeys tests at 5% significance level. Results Fillapex® and Sealapex® showed significantly less dye leakage than Endo-CPM-Sealer® (p<0.05). Conclusions It was concluded that Fillapex® and Sealapex® were able to prevent apical dye leakage differently from Endo-CPM-Sealer®.

Evaluation of alveolar socket response to Angelus MTA and experimental light-cure MTA

OBJECTIVE The aim of this study was to evaluate the rat alveolar socket response to implanted polyethylene tubes filled with a light-cured MTA or Angelus MTA. STUDY DESIGN Fifty-seven Wistar rats received an implant filled with one of the materials in the dental socket of the right central incisor. After 30, 60, and 90 days, animals were killed, and the right hemimaxillas were removed and processed to be analyzed on light microscopy. After embedding in paraffin, 6-μm-thick sections were obtained and stained with hematoxylin and eosin. Qualitative and quantitative analyses of the reaction were performed. RESULTS It was observed that the light-cured MTA presented a similar response compared with Angelus MTA, characterized by the reduction of the chronic inflammatory response and organization of the alveolar bone close to the materials, especially at the 90th day of observation. CONCLUSIONS It was concluded that both materials were well accepted by the alveolar tissue of rats, with the formation of mineralized tissue close to the materials.

Root canal treatment with calcium hydroxide: II. Effect of instrumentation beyond the apices

Root canals of dog premolar teeth were instrumented beyond the apices and enlarged up to the size of a No. 40 or 80 file and filled with calcium hydroxide up to the foramen. Ninety days later the histologic data showed more favorable results with the root canals instrumented until file No. 80.

Root canal treatment with calcium hydroxide. III. Effect of debris and pressure filling.

Root canals of dog premolar teeth with or without debris were filled with calcium hydroxide with or without pressure. The histologic results, 90 days after treatment, showed better results in the specimens without debris. More favorable results were obtained with the pressure filling when debris was present in small amounts.

Reaction of rat connective tissue to a new calcium hydroxide–based sealer

The aim of this study was to histopathologically examine the reaction of the connective tissue of rats to 2 calcium hydroxide-based sealers, Acroseal and Sealapex. Dentin tubes containing the materials and empty control tubes were implanted into the dorsal connective tissue of 36 Wistar albino rats. The animals were killed after 7 or 30 days, and the specimens were prepared for histologic analysis with hematoxylin and eosin, Von Kossa technique, and polarized light. Results were statistically analyzed using Kruskal-Wallis test. Both materials caused mild or moderate inflammatory reactions on the 7th day, but these reactions decreased by the 30th day with no significant difference at any time (P > .05). Mineralization of the subcutaneous tissue of the rats was observed only with Sealapex.

Effect of MTA-based sealer on the healing of periapical lesions.

Some manufacturers have recently added specific components to improve the ease of handling and insertion material properties of MTA in order to create MTA-based sealers. Objective: The aim of this study was to evaluate the healing of periapical lesions in canine teeth after a single session of endodontic treatment with MTA Fillapex® compared with Sealapex or Endo-CPM-Sealer®. Material and Methods: Sixty-two root canals were performed on two 1-year-old male dogs. After coronal access and pulp extirpation, the canals were exposed to the oral cavity for 6 months in order to induce periapical lesions. The root canals were prepared, irrigated with a solution of 2.5% sodium hypochlorite and filled with gutta-percha and different sealers, according to the following groups: 1) Sealapex; 2) Endo-CPM-Sealer®; and 3) MTA Fillapex. Some teeth with periapical lesions were left untreated for use as positive controls. Healthy teeth were used as negative controls. After 6 months, the animals were sacrificed and serial sections from the roots were prepared for histomorphologic analysis and stained with hematoxylin and eosin and the Brown and Brenn technique. The lesions were scored according to pre-established histomorphologic parameters and the scores statistically analyzed using the Kruskal-Wallis test. Results: All 3 materials produced similar patterns of healing (p>0.05); in particular, persistent inflammation and absence of complete periapical tissue healing were consistently noted. Conclusions: Preparation of the infected root canals followed by filling with the materials studied was insufficient to provide complete healing of the periapical tissues.