Alberto Consolaro

Cone-beam computerized tomographic, radiographic, and histologic evaluation of periapical repair in dogs' post-endodontic treatment.

OBJECTIVE To evaluate the periapical repair after root canal treatment in the teeth of dogs using CT and conventional radiography and to compare these findings with the gold standard microscopic evaluation. STUDY DESIGN The animals were divided into three groups according to endodontic treatment performed: Group 1, single-visit endodontic treatment in teeth without apical periodontitis; Group 2, single-visit endodontic treatment in teeth with apical periodontitis; and Group 3, endodontic treatment in teeth with apical periodontitis using calcium hydroxide as a root canal dressing. Group 4 consisted of teeth with apical periodontitis not submitted to root canal treatment and Group 5 consisted of healthy teeth without periapical disease. Radiographic, tomographic, and microscopic evaluations were performed by blind examiners. At 180 days experimental time, CT and radiographic measurements of periapical disease were compared with the gold standard microscopic measurement using intraclass correlation coefficient. Intergroup comparisons considering different methods of periapical lesions measurement or different clinical protocols of root canal treatment were performed by Kruskal Wallis test followed by Dunn. Integrity of lamina dura, presence of radiolucent areas, and presence of root resorption were analyzed by Fishers exact test. RESULTS There was discontinuity of the lamina dura and CPD in all teeth from Groups 2, 3, and 4 evaluated by tomography and radiography 45 days after CPD induction. Radiographically, 180 days after root canal treatment, there was no periapical lesion in teeth from Groups 1 and 3, different from groups 2 and 4 (p < .05). The highest reduction in the CPD size was observed on Group 3 (p < .05). According to the tomographic results, there was decrease of the size of the CPD on Group 3 but not on Groups 2 or 4. However, in all groups the periapical lesions presented larger mesio-distal extension if compared with radiography, both 45 days after CPD induction and 180 days after root canal treatment. At 180 days, CT measurements were closely related to microscopic results (ICC = 0.95) differently from radiographic evaluation (ICC = 0.86). CONCLUSION CT Scan evaluation of periapical repair following root canal treatment provided similar information than that obtained by microscopic analysis, whereas radiographic evaluation underestimated the size do periapical lesion.

Cementoenamel Junction: Microscopic Analysis and External Cervical Resorption

There is a lack of data regarding the shapes and distribution of the mineralized tissue that composes the cementoenamel junction. A sample of 198 permanent human teeth was analyzed by optical microscopy and scanning electron microscopy. Scanning electron microscopy showed three types of tissue interrelations: enamel overlapped by cementum; enamel and cementum edge-to-edge; and a gap, revealing a strip of exposed dentin. Using optical microscopy, a fourth type of cementoenamel junction was observed: cementum overlapped by enamel. The distribution of the hard tissues found at the cementoenamel junction is unpredictable and irregular both for any tooth type (e.g. on cuspids) and on any one individual tooth. Based on these results and on analysis of the mechanisms involved in cervical root resorption, it is possible to consider the cervical region as prone to external resorption.

Mineral Trioxide Aggregate with or without Calcium Chloride in Pulpotomy

The aim of this study was to evaluate the reaction of the pulp tissue against mineral trioxide aggregate (MTA) with or without 10% calcium chloride (CaCl(2)). Pulpotomies were performed in 4 canines and 8 premolars of two 8-month-old dogs. MTA with or without CaCl(2) was applied on the pulp tissue. The animals were killed after 90 days, and the specimens were processed for the microscopic analysis. Pulp tissue response was similar for MTA with and without CaCl(2). Pulp vitality was present in all specimens, along with pulp repair with formation of mineralized tissue bridging. The addition of CaCl(2) to MTA did not change its biologic properties in formation of mineralized barrier after pulpotomy.

Periradicular repair after two-visit endodontic treatment using two different intracanal medications compared to single-visit endodontic treatment

The number of appointments necessary to treat infected root canals is one of the most controversial issues in endodontics. This study evaluated, in dogs, the response of the periradicular tissues to the endodontic treatment of infected root canals performed in a single visit or in two visits, using different interappointment dressings. Periradicular lesions were induced by inoculating Enterococcus faecalis in the root canals. After confirming that a periradicular lesion developed, the root canals were treated within one or two visits, using either ozonized oil or calcium hydroxide in camphorated paramonochlorophenol (CMCP) as an intracanal medication. After 6 months, the animals were sacrificed and the specimens were processed for histological and histobacteriological analysis. The root canals treated in a single visit showed a success rate of 46%. When a calcium hydroxide/CMCP-based interappointment intracanal medication was used, 74% of the cases were categorized as success. In cases where ozonized oil was used as the intracanal medication, a success rate of 77% was observed. These results of the present study demonstrated that the two-visit treatment offered a higher success rate compared to one-visit therapy. In addition, ozonized oil may potentially be used as an intracanal medication.

Secondary caries around amalgam restorations

Secondary caries is one of the greatest causes for replacement of amalgam restorations. This study verified whether marginal defects in class I restorations could be a determining factor in the development of secondary caries. Fifty-five extracted premolars and molars whose occlusal surfaces were already restored with amalgam were selected. A macroscopic examination of these teeth was carried out to see whether there was a difference in the prevalence of caries beneath ditched and nonditched margins. To assess the presence of caries, a section was ground in each tooth so that the cut passed through a ditched margin and a better margin. This permitted assessment of the two types of margins that had been exposed to the same oral environment. Macroscopic examination revealed caries in 3.6% of the nonditched margins and caries in 20% of the ditched margins. Microscopic examination revealed caries in 47.06% of the nonditched margins and caries in 58.82% of the ditched margins. Statistical analysis supports the conclusion that the marginal defect itself is insufficient to determine the presence of secondary caries that surround the amalgam restoration on the occlusal surface.

Evaluation of cell culture cytotoxicity of five root canal sealers

The cytotoxicity of four calcium hydroxide-based root canal sealers (Sealapex, CRCS, Apexit, and Sealer 26) and one zinc oxide-eugenol-based sealer (Fill Canal) was evaluated microscopically for morphological changes in rat peritoneal macrophages. The least cytotoxic sealer was Fill Canal, followed in increasing order of cytotoxicity by CRCS, Sealer 26, Apexit, and Sealapex.

Comparative study of tissue response to polyglecaprone 25, polyglactin 910 and polytetrafluorethylene suture materials in rats

The authors evaluated the biocompatibility of three suture materials, polyglecaprone 25, polyglactin 910 and polytetrafluorethylene, implanted into subcutaneous tissue in the dorsal region of 20 Wistar albinus rats. After periods of 2, 7, 14 and 21 days, the rats were sacrificed and the specimens were processed for routine histotechnical analysis and stained with hematoxylin and eosin. The rate of fibrosis, angioblastic and fibroblastic proliferation, and also the intensity of inflammation were observed with the optic microscope. The results showed that polyglecaprone 25 suture material induced a mild inflammatory reaction, followed by polyglactin 910 and polytetrafluorethylene, respectively. Such biological behavior must be considered during the selection of the suture material to be used in oral surgery.

A scanning electron microscopic study of hypercementosis

The purpose of this study was to evaluate morphological characteristics of teeth with hypercementosis that are relevant to endodontic practice. Twenty-eight extracted teeth with hypercementosis had their root apexes analyzed by scanning electron microscopy (SEM). The teeth were divided according to tooth groups and type of hypercementosis. The following aspects were examined under SEM: the contour and regularity of the root surface; presence of resorption; presence and number of apical foramina, and the diameter of the main foramen. The progression of club shape hypercementosis was directly associated with the presence of foramina and apical foramen obstruction. Cases of focal hypercementosis presented foramina on the surface, even when sidelong located in the root. Circular cementum hyperplasia form was present in 2 out of 3 residual roots, which was the highest proportion among the tooth types. The detection of a large number of foramina in the apical third of teeth with hypercementosis or even the possible existence of apical foramen obliteration contributes to understand the difficulties faced during endodontic treatment of these cases.

Subcutaneous connective tissue response to primary root canal filling materials

This study evaluated the response of the subcutaneous connective tissue of BALB/c mice to root filling materials indicated for primary teeth: zinc oxide/eugenol cement (ZOE), Calen paste thickened with zinc oxide (Calen/ZO) and Sealapex sealer. The mice (n=102) received polyethylene tube implants with the materials, thereby forming 11 groups, as follows: I, II, III: Calen/ZO for 7, 21 and 63 days, respectively; IV, V, VI: Sealapex for 7, 21 and 63 days, respectively; VII, VIII, IX: ZOE for 7, 21 and 63 days, respectively; X and XI: empty tube for 7 and 21 days, respectively. The biopsied tissues were submitted to histological analysis (descriptive analysis and semi-quantitative analysis using a scoring system for collagen fiber formation, tissue thickness and inflammatory infiltrate). A quantitative analysis was performed by measuring the area and thickness of the granulomatous reactionary tissue (GRT). Data were analyzed by Kruskal-Wallis, ANOVA and Tukeys post-hoc tests (?=0.05). There was no significant difference (p>0.05) among the materials with respect to collagen fiber formation or GRT thickness. However, Calen/ZO produced the least severe inflammatory infiltrate (p<0.05). The area of the GRT was significantly smaller (p<0.05) for Calen/ZO and Sealapex. In conclusion, Calen/ZO presented the best tissue reaction, followed by Sealapex and ZOE.

Anti-dentine antibodies with root resorption during orthodontic treatment

The aim of this study was to analyse serum IgG levels and salivary secretory IgA (sIgA) levels in human dentine extract (HDE) before (T0) and 6 months after (T6) orthodontic treatment and to correlate anti-HDE autoantibodies to root resorption. Fifty orthodontic patients were selected, 19 males (15.6 ± 8.5 years) and 31 females (21.4 ± 11.2 years), 19 in the mixed dentition (10.3 ± 1.9 years) and 31 in the permanent dentition (24.6 ± 9.9 years). Fifty individuals not undergoing orthodontic treatment matched by gender and age were selected as the controls. Periapical radiographs of the upper central incisors and saliva sampling were obtained of all patients at T0 and T6. Serum samples were collected from the permanent dentition patients (n = 31). Antibody levels were determined by means of immunoenzyme assay. At T6, root resorption was classified as grade 0 (no resorption), grade 1 (slight resorption), and grade 2 (moderate to severe resorption). Differences between antibody levels at T0 and T6 and among different grades of resorption were determined by paired t- and Kruskal-Wallis tests, respectively. Spearmans rank correlation coefficient was applied to detect correlation between sIgA and IgG levels, and logistic regression to determine the association of root resorption grade and the studied variables. Differences were considered significant at P < 0.05. Serum anti-HDE IgG levels decreased (P < 0.01) in grade 2 root resorption patients during treatment and was not correlated to salivary sIgA levels or other variables. Patients who had grade 2 root resorption at T6 showed higher levels of anti-HDE sIgA (P < 0.001). Anti-HDE sIgA levels at T0 and root shape were the main factors associated with the degree of root resorption. The results suggest that variations to systemic and local humoural immune response to dentine antigens may occur during orthodontic treatment. High levels of salivary sIgA before treatment were associated with more advanced lesions after 6 months of treatment.