Three-dimensional dental arch changes of patients submitted to orthodontic-surgical treatment for correction of Class II malocclusion

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Immediate loading of implants installed in a healed alveolar bony ridge or immediately after tooth extraction: an experimental study in dogs

ObjectiveTo compare the sequential healing at immediately loaded implants installed in a healed alveolar bony ridge or immediately after tooth extraction.Material and methodsIn the mandible of 12 dogs, the second premolars were extracted. After 3months, the mesial roots of the third premolars were endodontically treated and the distal roots extracted. Implants were placed immediately into the extraction sockets (test) and in the second premolar region (control). Crowns were applied at the second and third maxillary premolars, and healing abutments of appropriate length were applied at both implants placed in the mandible and adapted to allow occlusal contacts with the crowns in the maxilla. The time of surgery and time of sacrifices were planned in such a way to obtain biopsies representing the healing after 1 and 2weeks and 1 and 3months. Ground sections were prepared for histological analyses.ResultsAt the control sites, a resorption of the buccal bone of 1mm was found after 1week and remained stable thereafter. At the test sites, the resorption was 0.4mm at 1-week period and further loss was observed after 1month. The height of the peri-implant soft tissue was 3.8mm both at test and control sites. Higher values of mineralized bone-to-implant contact and bone density were seen at the controls compared with the test sites. The differences, however, were not statistically significant.ConclusionsDifferent patterns of sequential early healing were found at implants installed in healed alveolar bone or in alveolar sockets immediately after tooth extractions. However, three months after implant installation, no statistically significant differences were found for the hard- and soft-tissue dimensions.

Calcium hydroxide root canal sealers - Histopathologic evaluation of apical and periapical repair after endodontic treatment

Eighty root canals of the premolars of 4 dogs, with vital pulp, were instrumented and filled during the same session with the Sealapex, CRCS, Sealer 26, and Apexit sealers, the animals were sacrificed 180 days after root canal filling and their maxillae and mandibles were removed and fixed in 10% formalin, After routine histologic processing, the sections were stained with hematoxylin-eosin and Mallory trichrome, Histopathologic analysis showed that Sealapex was the sealer that best permitted the deposition of mineralized tissue at the apical level and was the only sealer that provided complete sealing (37.5% of cases), With the use of Sealapex, no inflammatory infiltrate occurred and there was no reabsorption of mineralized tissues, In contrast, partial sealing and a moderate inflammatory infiltrate occurred with the use of CRCS, When Apexit and Sealer 26 were used the absence of sealing was frequent and active reabsorption of mineralized tissues occurred in most cases, the inflammatory infiltrate predominating with the use of Apexit was of the severe type, whereas with the use of Sealer 26 the inflammatory infiltrate was mild or absent.

Influence of occlusal contact area on cusp defection and stress distribution

The purpose of this study was to evaluate the effect of occlusal contact area for loading on the cuspal defection and stress distribution in a first premolar restored with a high elastic modulus restorative material. The Rhinoceros 4.0 software was used for modeling the three-dimensional geometries of dental and periodontal structures and the inlay restoration. Thus, two different models, intact and restored teeth with three occlusal contact areas, 0.1, 0.5 and 0.75 mm(2), on enamel at the occlusal surface of buccal and lingual cusps. Finite element analysis (FEA) was performed with the program ANSYS (Workbench 13.0), which generated a mesh with tetrahedral elements with greater refinement in the regions of interest, and was constrained at the bases of cortical and trabecular bone in all axis and loaded with 100 N normal to each contact area. To analysis of maximum principal stress, the smaller occlusal contact area showed greater compressive stress in region of load application for both the intact and inlay restored tooth. However, tensile stresses at the occlusal isthmus were similar for all three tested occlusal contact areas (60 MPa). To displacement of the cusps was higher for teeth with inlay (0.46-0.48 mm). For intact teeth, the smaller contact area showed greater displacement (0.10 mm). For teeth with inlays, the displacement of the cusps were similar in all types of occlusal area. Cuspal displacement was higher in the restored tooth when compared to the intact tooth, but there were no significant variations even with changes in the occlusal contact area. RELEVANCE CLINICAL: Occlusal contacts have a great influence on the positioning of teeth being able to maintain the position and stability of the mandible. Axial loads would be able to generate more uniform stress at the root presenting a greater concentration of load application in the point and the occlusal surface. Thus, is necessary to analyze the relationship between these occlusal contacts as dental wear and subsequent occlusal interferences.

Porosity and sealing ability of root fillings with gutta-percha and BioRoot RCS or AH Plus sealers. Evaluation by three ex vivo methods

To investigate the ability of BioRoot RCS, a tricalcium silicate-based root canal sealer and AH Plus to effectively fill the root canals of contralateral teeth using three evaluation methods, and to investigate also the correlation between the methods. The prepared root canals of ten pairs of contralateral mandibular premolar teeth were filled with gutta-percha and sealer using lateral compaction. The percentage of voids within the root canal was assessed by micro-computed tomography, whilst sealing ability was investigated by fluid transport and leakage of fluorescent microspheres. The interaction of sealer with dentine, and sealer penetration were assessed by confocal microscopy. The void volume, fluid flow, microsphere leakage and sealer interaction with dentine for both materials were compared. Nonparametric (Mann-Whitney) tests were used to compare the % void and fluid transport of the two sealers. Spearman correlation was used to assess the pairwise relationships between the techniques. The level of significance was set to 0.05. BioRoot RCS exhibited significantly more percentage of voids than AH Plus. There was no difference in fluid flow and microsphere penetration. BioRoot RCS exhibited a different pattern of sealer penetration and interaction with the dentine walls compared to AH Plus. For both materials, the pairwise correlations between the three techniques were close to zero, indicating weak relationships. MicroCT analysis revealed a higher void volume for BioRoot RCS. The other techniques did not show a difference between the sealing ability of the sealers. The correlation between the three ex vivo methods of assessment was weak demonstrating their complementarity rather than their concordance.

Estudo da erupção dos dentes caninos, primeiros e segundos premolares dos lados direito e esquerdo, pelo método radiográfico

The tooth eruption have been studied for many years about the knowledge of its variations. From these variations the difference between the eruption of the superior and inferior archs, and also the right and left sides have been poorly analysed. The author compared the alveolar eruption of the permanents canines, first and second premolars between the right and left sides of the superior and inferior archs, from 7 and 11 years of age, in males and females, by radiographic method. By the Discipline of Radiology of the Diagnosis and surgery Departament of the School of Dentistry of São José dos Campos - UNESP, observed that: there is early eruption in female; the alveolar eruption sequence in maxillar and mandibular was: first premolar, second premolar e canino. There wasn't statiscally significant difference of the alveolar eruption between the right and left sides of maxillar and mandibular archs

Processamento digital de imagens de radiografias periapicais sub-expostas aos raios X

The aim of this study was to evaluate whether digitized images obtained from periapical radiographs taken with low dose of radiation could be improved with the aid of a computer software (PhotoStyler) for digital treatrnent. Serial and standardized radiographs of molar and premolar areas were studied. A total of 57 images equivalent to the radiographs taken with reduced exposure time ( 60 and 80% of the time considered normal), digitized and treated, were submitted to the evaluation of seven exanúners which compared them with those images without treatment. lt was verified that about 80% of the images equivalem to lhe radiographs taken with 60% reduction of ordinary exposure time were considered to having quality for supporting diagnosis. As for the images taken with 80% reduction of ordinary exposure time, about 50% of them were considered suitable for the sarne purpose

Avaliação da perda óssea alveolar em pacientes encaminhados à especialista em periodontia: estudo radiográfico

The aim of this study was to evaluate the mean of alveolar bone loss (%) in radiographies of patients referred to specialist for periodontal treatment. Full mouth series of periapical radiographies (paralelism technique) were used. A total of 9808 proximal surfaces in 4804 teeth of 213 patients (90 males and 123 females), mean age, 44.3 years, were assessed. The alveolar bone loss was measured in relation to root lenght expressed as an average similar to Schei 's technique (1959) without the use of ruler. The references used were the distances cement-enamel juntion (CEJ) - alveolar crest (AC) and CEJ- dental apex taken with a digimatic caliper. The results showed that the mean values of alveolar bone loss (%ABL) was 22.39%. Men showed higher mean values of %ABL than women; the %ABL increased with the age, but the difference among age groups was no statistical significant (p>0.05); the mean values of %ABL of distal surfaces was higher than mesial surfaces (p<0.01), ríght quadrants exhibited higher %ABL values than left quadrants (p<0.01); maxillary sites showed mean values of %ABL higher than mandibular sites; the highest mean values of %ABL was found in molar group, followed by incisor groups, and premolar group; the canine group exhibited lower mean values of %ABL; the differences among the groups was considered statitistically significant (p<0.01). lt was suggested the usage of this technique in the dentistry offices and radiological services for the patient 's documentation and assortment and for later comparison about alveolar bone level

Multidisciplinary approach for crown-root fracture treatment after trauma: case report

The development of an accurate diagnosis and appropriate treatment plan can be a complex task, especially in cases of dentoalveolar trauma. The authors present a case report of crown-root fracture caused by trauma and highlight the importance of a multidisciplinary approach for the treatment. An eighteen year-old boy had a bicycle accident resulting in dental trauma. The upper right first molar showed a complicated crownroot fracture and the lower left second pre-molar showed an uncomplicated crown-root fracture. Endodontic treatment, controlled tooth extrusion, periodontal surgery for recovery of biological width, and porcelain crown and onlay restorations were performed. Esthetic and functional results were achieved. At the two-year follow-up it was observed that the tooth/onlay interface of the upper right first molar was stained and the onlay of the left lower second pre-molar was fractured. Therefore, the interface stained was repaired and a porcelain crown was made for the lower second premolar. The clinical case presented herein leads to the conclusion that a multidisciplinary treatment plan is extremely important for a proper resolution in cases of dentoalveolar trauma.

Tumor odontogênico queratocístico: relato de caso

Introduction: The odontogenic keratocyst tumor (OKT) derived from dental lamina rests with particularities and specific histological features, with high rates of relapse and aggressive clinical behavior. Presents certain predilection for males, affecting the mandible of 60% to 80% of cases may be related to impacted tooth 25 to 45% of cases. Objective: To highlight the clinical, histopathological and imaging procedures of the OKT, as well as discuss the treatment of this injury. Case Report: To report a case of 10 years of age to look for the orthodontist to correct anterior open bite was observed in panoramic radiography radiolucent area in the region of the body of the mandible associated with pathological inclusion of the lower premolar. It was performed an incisional biopsy of the lesion and the histopathologic diagnosis was odontogenic keratocyst tumor. It was performed a CT scan to assess the extent of the injury and its relation to anatomic structures. How to conduct, we opted for the extraction of the deciduous molar and enucleation of the lesion, preserving the premolar included. The same goes on clinical and radiographic control 18 months, after removal of OKT obtaining the eruption of premolar that was involved in the injury. Final Comments: It is necessary to adopt protocols that include dental care knowledge of oral diagnosis, medical history and careful clinical evaluation without forgetting the need for histopathological confirmation.

Avaliação do uso de uma estrutura de nylon modificada como reforço de prótese totalmente acrílica implantossuportada

Pós-graduação em Odontologia Restauradora - ICT

Role of teeth adjacent to implants installed immediately into extraction sockets: an experimental study in the dog

Aim: To evaluate the influence of the presence of both adjacent teeth on the level of alveolar bony crest at sites where implants were installed into the socket immediately after tooth extraction. Material and methods: Six Labrador dogs were used. Extractions of all teeth from the second premolar to the first molar were performed in the right side of the mandible, after full-thickness flap elevation. In the left side of the mandible, an endodontic treatment of the mesial root of the third and fourth premolars was performed. Full-thickness flaps were elevated, the teeth hemisected, and the distal roots removed. Immediately after, implants were bilaterally installed with the margin flush to the buccal bony crest. The implants were placed in the center of the alveolus at the third premolars and toward the lingual bony plate of the alveolus at the fourth premolars. After 3 months of healing, the animals were euthanized. Results: All implants were integrated in mature bone. More bone resorption was observed at the test compared to the control sites. At the buccal aspect, a resorption of 2.8 +/- 0.5 and 1.6 +/- 0.4 mm at the third premolars and of 2.4 +/- 0.6 and 0.8 +/- 0.7 mm at the fourth premolars were found, at the test and control sites, respectively. At the lingual aspect, the bony crest was apically located in relation to the implant shoulder 1.5 +/- 0.3 and 0.5 +/- 0.5 mm at the third premolars and 1.6 +/- 0.6 and 0.3 +/- 1.1 mm at the fourth premolars, at the test and control sites, respectively. A lower buccal bone resorption was found at the control implants placed lingually. Conclusion: Multiple extractions of teeth adjacent to a socket into which implants were installed immediately after, tooth extraction induced more alveolar bone recession compared to sites where the adjacent teeth were preserved. Moreover, an implant placed more lingually yielded less recession of the buccal aspect of the implant.

Finite element analysis of bonded model Class I 'restorations' after shrinkage

Objectives. The C-Factor has been used widely to rationalize the changes in shrinkage stress occurring at the tooth/resin-composite interfaces. Experimentally, such stresses have been measured in a uniaxial direction between opposed parallel walls. The situation of adjoining cavity walls has been neglected. The aim was to investigate the hypothesis that: within stylized model rectangular cavities of constant volume and wall thickness, the interfacial shrinkage-stress at the adjoining cavity walls increases steadily as the C-Factor increases. Methods. Eight 3D-FEM restored Class I 'rectangular cavity' models were created by MSC.PATRAN/MSC.Marc, r2-2005 and subjected to 1% of shrinkage, while maintaining constant both the volume (20 mm(3)) and the wall thickness (2 mm), but varying the C-Factor (1.9-13.5). An adhesive contact between the composite and the teeth was incorporated. Polymerization shrinkage was simulated by analogy with thermal contraction. Principal stresses and strains were calculated. Peak values of maximum principal (MP) and maximum shear (MS) stresses from the different walls were displayed graphically as a function of C-Factor. The stress-peak association with C-Factor was evaluated by the Pearson correlation between the stress peak and the C-Factor. Results. The hypothesis was rejected: there was no clear increase of stress-peaks with C-Factor. The stress-peaks particularly expressed as MP and MS varied only slightly with increasing C-Factor. Lower stress-peaks were present at the pulpal floor in comparison to the stress at the axial walls. In general, MP and MS were similar when the axial wall dimensions were similar. The Pearson coefficient only expressed associations for the maximum principal stress at the ZX wall and the Z axis. Significance. Increase of the C-Factor did not lead to increase of the calculated stress-peaks in model rectangular Class I cavity walls. (C) 2011 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

In vitro effects of Er,Cr:YSGG laser on dentine hypersensitivity. Dentine permeability and scanning electron microscopy analysis

The aim of the present study was to determine clinical parameters for the use of Er,Cr:YSGG laser in the treatment of dentine hypersensitivity. Two antagonist areas were determined as control and experimental areas for irradiation in 90 premolar roots. Each surface was conditioned with 24% EDTA (sub-group 1) and 35% phosphoric acid (sub-group 2) and irradiated with the following settings: 1) Er:YAG, 60 mJ, 2 Hz, defocused; groups 2 to 9: irradiation with Er,Cr:YSGG laser, 20 Hz, Z6 tip, 0% of air and water: 2) Er,Cr:YSGG 0.25 W; 3) 0.5 W; 4) 0.75 W; 5) 1.0 W; 6) 1.25 W, 7) 1.50 W, 8) 2 W; 9) 2 W. After irradiation, samples were immersed in methylene blue solution and included in epoxy resin to obtain longitudinal cuts. The images were digitalized and analyzed by computer software. Although the samples irradiated with Er:YAG laser showed less microleakage, sub-group 1 showed differences between the groups, differing statistically from groups 3, 6, and 9. The results of sub-group 2 showed that the mean values of Er:YAG samples showed a negative trend, however, no differences were detected between the groups. For scanning electron microscopy analysis, dentine squares were obtained and prepared to evaluate the superficial morphology. Partial closure of dentinal tubules was observed after irradiation with Er:YAG and Er,Cr:YSGG laser in the 0.25 and 0.50 W protocols. As the energy densities rose, open dentinal tubules, carbonization and cracks were observed. It can be concluded that none of the parameters were capable of eliminating microleakage, however, clinical studies with Er:YAG and Er,Cr:YSGG lasers should be conducted with the lowest protocols in order to determine the most satisfactory setting for dentine hypersensitivity.

Effect of electromagnetic field on bone regeneration around dental implants after immediate placement in the dog mandible: a pilot study

Background: Accelerating bone healing around dental implants can reduce the long-term period between the insertion of implants and functional rehabilitation. Objective: This in vivo study evaluated the effect of a constant electromagnetic field (CEF) on bone healing around dental implants in dogs. Materials and methods: Eight dental implants were placed immediately after extraction of the first premolar and molar teeth on the mandible of two male dogs and divided into experimental (CEF) and control groups. A CEF at magnetic intensity of 0.8 mT with a pulse width of 25 mu s and frequency of 1.5 MHz was applied on the implants for 20 min per day for 2 weeks. Result and conclusion: After qualitative histological analysis, a small quantity of newly formed bone was observed in the gap between the implant surface and alveolar bone in both groups.