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1.
Clin Oral Investig ; 2021 Mar 25.
Artigo em Inglês | MEDLINE | ID: mdl-33765193

RESUMO

OBJECTIVES: To evaluate the effect of ionizing radiation and cariogenic biofilm challenge using two continuous flow models, normal and reduced salivary flow, on the development of initial root-dentin caries lesions. MATERIALS AND METHODS: Microcosm biofilms were grown under two salivary flow rates (0.06 and 0.03 mL min-1) and exposed to 5% sucrose (3 × daily, 0.25 mL min-1, 6 min) dripped over non-irradiated and irradiated root-dentin blocks for up to 7 days. The vibration modes of root dentin, matrix/mineral (M/M), and carbonate/mineral (C/M) ratios were evaluated by FTIR. The mineral density was assessed by micro-CT. RESULTS: With normal salivary flow, FTIR revealed an increase in the organic matrix (amide III) and a decrease in the mineral phase (ν4, ν2 PO43-, AII + ν2 CO32-, C/M) in caries lesions. Irradiated dentin exhibited a reduction in the mineral phase (ν1, ν3 PO43-, ν2 CO32-, C/M). Differences in mineral densities were not significant. With reduced salivary flow, FTIR also revealed increased organic matrix (amide III) for irradiated caries lesions and decrease in mineral phase (v4, v2 PO43-, v2 CO32-, and C/M) in caries lesions. ν1, ν3 PO43- precipitated on the surface of irradiated dentin and a lower mineral density was observed. CONCLUSIONS: Initial caries lesions differed between non-irradiated and irradiated dentin and between normal and reduced salivary flow rates. Significant mineral loss with exposure of the organic matrix and low mineral density were observed for irradiated dentin with a reduced salivary flow rate. CLINICAL RELEVANCE: Ionizing radiation associated with a reduced salivary flow rate enhanced the progression of root-dentin caries.

2.
Braz. oral res. (Online) ; 35: e001, 2021. tab, graf
Artigo em Inglês | LILACS-Express | LILACS, BBO - Odontologia | ID: biblio-1132750

RESUMO

Abstract: Three-point bending test is the most common mechanical test used for quantifying the biomechanical quality of bone tissue and bone healing in small animals. However, there is a lack of standardization for evaluation of bone repair by cortical perforation. The aim of this study was to determine the influence of bone defect position in the proximal metaphysis of rat tibias during load application and different span configuration on the three-point bending test outcomes. Cortical defects with 1.6 mm diameter were created at a standardized location on the medial surface of 60 tibias of male Wistar rats. The animals were euthanized 7 days after surgery. Five specimens were used to create 3D models for finite element analysis using high-resolution micro-CT images. Two spans (6 and 10mm) and three positions of the bone defect in relation to the load application (upward, frontal and downward) were evaluated experimentally (n = 10) and in finite element analysis (n = 5). Maximum load (N) and stiffness (N/mm) were statistically analyzed with 2-way ANOVA and Tukey test (α = 0.05). The results demonstrated that span and orientation of the bone defect significantly influenced the fracture pattern, stress distribution and force versus displacement relation. Therefore, reliable outcome can be achieved creating the bone defect at 8 mm from the extremity of the proximal epiphysis; placing a 10 mm distance span and downward facing defect position to allow a better distribution of stress and more fracture patterns that reached the bone defect target area with less intra-group variability.

3.
Dent Traumatol ; 2020 Nov 20.
Artigo em Inglês | MEDLINE | ID: mdl-33217137

RESUMO

BACKGROUND/AIM: Little is known about the effect of dental trauma and mouthguards (MG) on teeth with ceramic laminate veneers (CLV). The aim was to evaluate the influence of CLV thickness and the presence of a MG with and without antagonist tooth contact on impact stresses during dental trauma. MATERIALS AND METHODS: Twelve 2D-finite element models of a head with maxillary structures and upper incisors, six with and six without antagonist tooth, were created in three CLV conditions: sound incisor (no CLV), 0.3 mm CLV, and 1.0 mm CLV. These were evaluated with and without a 4.0-mm ethylene-vinyl acetate MG, with and without an antagonist tooth. An impact analysis was performed in which the head frontally hits a rigid surface at a speed of 1 m/s (3.6 km/h). The results were analyzed using Critical modified von Mises (MPa). The mean of the 10% highest modified von Mises stresses in each structure was collected. RESULTS: MG presence substantially reduced impact stresses in the CLV and tooth structures. The contact of the antagonist tooth promoted better stress distribution and reduced the stress levels in the traumatized tooth. Critical stress areas were found in the palatal enamel, incisal enamel, labial cervical area, and enamel under the CLV for all models without MG. In the models with MG, the stresses reduced significantly. Critical modified von Mises stress showed that sound or prepared enamel experienced more critical impact stresses than 0.3 or 1.0-mm thick CLV. CONCLUSIONS: The use of 4.0 mm EVA mouthguard reduced the impact stress levels in models with 0.3-mm CLV and 1.0-mm CLV, similar to a sound tooth. The contact of an antagonist tooth and the MG better distributed the stresses and reduced the impact stress in the traumatized tooth.

4.
Braz Dent J ; 31(6): 589-597, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33237229

RESUMO

The progression of caries in permanent molar teeth of young patients, frequently result in endodontic treatment. This randomized blinded clinical trial assessed the effect of two endodontic sealers (Sealer 26 and AH Plus) on the incidence of pain and apical repair after endodontic treatment of young molar teeth, and secondly identify factors associated with the outcomes. Endodontic treatment was performed by undergraduate students in molar teeth (n=69) of young patients (n=54) at the Endodontic and Restorative Public Extension Clinic Service. Protaper Next was used and the endodontic sealers were allocated which were restored with direct composite resin. Two primary clinical outcomes - apical repair and postoperative pain, were assessed after 12 and 24 months for blinded operators. Description of incidence rates and mixed-model regression using Generalized Estimation Equations (GEE). After 2 years 69 molar teeth of 54 patients were evaluated. No effect of the endodontic sealer was observed irrespective of period of evaluation. Apical repair incidences and asymptomatic teeth were, respectively, 90.5 and 89.3, 96.8 and 90.0% during 1 and 2 years of follow-up. Failed apical repair was associated with unsatisfactory pulpectomy (p=0.003) and periapical conditions (p=0.007) as well as their interaction (p=0.016). None of these independent variables was able to predict the occurrence of pain in both periods. Prognosis of apical repair is dependent on the initial conditions. Endodontic treatment of young molars associated with composite resin restorations performed by undergraduate students have satisfactory results after 2 years and was effective to prevent the risk of permanent teeth loss.


Assuntos
Cárie Dentária , Dente Molar , Selantes de Fossas e Fissuras , Resinas Compostas , Humanos , Estudantes
5.
Braz Oral Res ; 35: e001, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33206774

RESUMO

Three-point bending test is the most common mechanical test used for quantifying the biomechanical quality of bone tissue and bone healing in small animals. However, there is a lack of standardization for evaluation of bone repair by cortical perforation. The aim of this study was to determine the influence of bone defect position in the proximal metaphysis of rat tibias during load application and different span configuration on the three-point bending test outcomes. Cortical defects with 1.6 mm diameter were created at a standardized location on the medial surface of 60 tibias of male Wistar rats. The animals were euthanized 7 days after surgery. Five specimens were used to create 3D models for finite element analysis using high-resolution micro-CT images. Two spans (6 and 10mm) and three positions of the bone defect in relation to the load application (upward, frontal and downward) were evaluated experimentally (n = 10) and in finite element analysis (n = 5). Maximum load (N) and stiffness (N/mm) were statistically analyzed with 2-way ANOVA and Tukey test (α = 0.05). The results demonstrated that span and orientation of the bone defect significantly influenced the fracture pattern, stress distribution and force versus displacement relation. Therefore, reliable outcome can be achieved creating the bone defect at 8 mm from the extremity of the proximal epiphysis; placing a 10 mm distance span and downward facing defect position to allow a better distribution of stress and more fracture patterns that reached the bone defect target area with less intra-group variability.

6.
Dent Traumatol ; 2020 Nov 13.
Artigo em Inglês | MEDLINE | ID: mdl-33185332

RESUMO

BACKGROUNDS/AIMS: Traumatic dental injuries with bone fractures require rigid splinting. The degree of rigidity of the wire-composite splints can be challenging. The aim of this study was to evaluate the effect of the rigidity of different wire-composite splints on alveolar process displacement. MATERIAL AND METHODS: A model was created using polystyrene resin to simulate the anterior maxilla, bovine incisors to simulate maxillary incisors, and polyether impression material to simulate the periodontal ligament. An alveolar process fracture was created, while maintaining the labial bone connection with the PDL. Four wire-composite splints (0.3, 0.6, 0.9, and 1.2 mm in diameter) were compared with models without splints and with no fracture (n = 5). The alveolar process displacement was measured (3 times per model/per splint type) at the fractured and adjacent central incisor regions using a deflectometer (Instron) under functional cycling and static loading (100 N). Data (µm) were analyzed using RM ANOVA, followed by Tukey's HSD test (α = 0.05). RESULTS: The displacement at the region of the adjacent incisor was not influenced by the splint during static and cycling load (P > .05). The Tukey test demonstrated that the model without splints had significantly higher alveolar process displacement at the traumatized teeth than that of all other splint models (P < .001). Increasing the wire diameter from 0.3 mm to 0.9 mm significantly reduced the alveolar process displacement (P < .001). No difference was observed between the 0.9 mm (P = .123) and 1.2 mm (P = .219) wire-composite splints irrespective of the measured tooth regions. CONCLUSIONS: The rigidity of the wire-composite splint significantly influenced the mobility of the fractured alveolar process. The use of at least 0.9 mm wire was effective in reducing the fractured alveolar process displacement to a level that was similar to the adjacent teeth.

7.
Braz. dent. j ; 31(6): 589-597, Nov.-Dec. 2020. tab, graf
Artigo em Inglês | LILACS-Express | LILACS, BBO - Odontologia | ID: biblio-1132356

RESUMO

Abstract The progression of caries in permanent molar teeth of young patients, frequently result in endodontic treatment. This randomized blinded clinical trial assessed the effect of two endodontic sealers (Sealer 26 and AH Plus) on the incidence of pain and apical repair after endodontic treatment of young molar teeth, and secondly identify factors associated with the outcomes. Endodontic treatment was performed by undergraduate students in molar teeth (n=69) of young patients (n=54) at the Endodontic and Restorative Public Extension Clinic Service. Protaper Next was used and the endodontic sealers were allocated which were restored with direct composite resin. Two primary clinical outcomes - apical repair and postoperative pain, were assessed after 12 and 24 months for blinded operators. Description of incidence rates and mixed-model regression using Generalized Estimation Equations (GEE). After 2 years 69 molar teeth of 54 patients were evaluated. No effect of the endodontic sealer was observed irrespective of period of evaluation. Apical repair incidences and asymptomatic teeth were, respectively, 90.5 and 89.3, 96.8 and 90.0% during 1 and 2 years of follow-up. Failed apical repair was associated with unsatisfactory pulpectomy (p=0.003) and periapical conditions (p=0.007) as well as their interaction (p=0.016). None of these independent variables was able to predict the occurrence of pain in both periods. Prognosis of apical repair is dependent on the initial conditions. Endodontic treatment of young molars associated with composite resin restorations performed by undergraduate students have satisfactory results after 2 years and was effective to prevent the risk of permanent teeth loss.


Resumo A rápida progressão das lesões de cárie nos dentes molares permanentes de pacientes jovens, frequentemente resulta no tratamento endodôntico. Este ensaio clinico randomizado cego avaliou o efeito de dois cimentos endodônticos (Sealer 26 e AH Plus) na incidência de dor e reparo apical após tratamento endodôntico de dentes molares jovens e identificar fatores associados aos desfechos do tratamento. O tratamento endodôntico foi realizado por estudantes de graduação em dentes molares permanentes (n=69) de pacientes jovens (n=54) na Clínica de Extensão Endodôntica e Restauradora da Universidade Federal de Uberlândia, Brasil. Protaper Next foi usado e os dois cimentos foram distribuídos aleatoriamente nas amostras, as quais foram restauradas com resina composta direta. Dois desfechos clínicos primários - reparo apical e dor pós-operatória foram avaliados após 12 e 24 meses por operadores de forma cega. Análise longitudinal dos dados incluiu a descrição das taxas de incidência e modelo de regressão misto usando Equações de Estimativa Generalizadas (GEE). As incidências (%) do reparo apical e dos dentes assintomáticos foram respectivamente 90,5/89,3 e 96,8/90,0 nos períodos de 1 e 2 anos de acompanhamento. Ausência de reparo apical foi associada com pulpectomia insatisfatória (p=0,003) e condições periapicais (p=0,007), bem como sua interação (p=0,016). Nenhuma dessas variáveis independentes foi capaz de prever a ocorrência de dor nos períodos de acompanhamento. O tratamento endodôntico mostrou resultados satisfatórios após 2 anos. O prognóstico do reparo apical depende das condições iniciais. Nenhum efeito do cimento endodôntico foi observado. O tratamento endodôntico de molares jovens associado com restaurações em resina composta realizado por estudantes de graduação tem um papel relevante na redução do risco de perda do dente permanente.

8.
J Appl Oral Sci ; 28: e20200191, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32997090

RESUMO

OBJECTIVE: This study analyzed the effect of ionizing radiation on bone microarchitecture and biomechanical properties in the bone tissue surrounding a dental implant. METHODOLOGY: Twenty rabbits received three dental morse taper junction implants: one in the left tibia and two in the right tibia. The animals were randomized into two groups: the nonirradiated group (control group) and the irradiated group, which received 30 Gy in a single dose 2 weeks after the implant procedure. Four weeks after the implant procedure, the animals were sacrificed, and the implant/bone specimens were used for each experiment. The specimens (n=10) of the right tibia were examined by microcomputed tomography to measure the cortical volume (CtV, mm3), cortical thickness (CtTh, mm) and porosity (CtPo, %). The other specimens (n=10) were examined by dynamic indentation to measure the elastic modulus (E, GPa) and Vickers hardness (VHN, N/mm2) in the bone. The specimens of the left tibia (n=10) were subjected to pull-out tests to calculate the failure load (N), displacement (mm) up to the failure point and interface stiffness (N/mm). In the irradiated group, two measurements were performed: close, at 1 mm surrounding the implant surface, and distant, at 2.5 mm from the external limit of the first measurement. Data were analyzed using one-way ANOVA, Tukey's test and Student's t-test (α=0.05). RESULTS: The irradiated bone closer to the implant surface had lower elastic modulus (E), Vickers hardness (VHN), Ct.Th, and Ct.V values and a higher Ct.Po value than the bone distant to the implant (P<0.04). The irradiated bone that was distant from the implant surface had lower E, VHN, and Ct.Th values and a higher Ct.Po value than the nonirradiated bone (P<0.04). The nonirradiated bone had higher failure loads, displacements and stiffness values than the irradiated bone (P<0.02). CONCLUSION: Ionizing radiation in dental implants resulted in negative effects on the microarchitecture and biomechanical properties of bone tissue, mainly near the surface of the implant.

9.
Braz Dent J ; 31(3): 337-343, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-32667512

RESUMO

Lateral luxation injuries are one of the most severe periodontal injuries in dental trauma. The correct diagnosis followed by repositioning of the tooth on the right position is fundamental for the periodontal ligament healing. This study reported a clinical case of lateral luxation of maxillary central incisor involving a new cone beam computed tomography (CBCT) software for reconstruction (e-Vol DX) to confirm the lateral luxation after no conclusive dental trauma injury definition by using conventional exam. The lateral luxation injury was digitally reduced by insertion of tooth back to its alveolus, and at the same session, the tooth was stabilized with a rigid splint and further changed to a semi-rigid nylon splint. During the pulpal status monitoring, the pulp was diagnosed necrotic, then the root canal was treated to prevent root resorption. External office-bleaching and restorative procedure was performed. The 4-years follow up and new imaging exam and digital reconstruction confirmed bone healing and no complication. CBCT images analyzed by eVol DX can be used to determine and to guide lateral luxation treatment.


Assuntos
Reabsorção da Raiz , Avulsão Dentária , Tomografia Computadorizada de Feixe Cônico , Humanos , Incisivo , Tratamento do Canal Radicular , Software
10.
Braz. dent. j ; 31(3): 337-343, May-June 2020. graf
Artigo em Inglês | LILACS-Express | LILACS, BBO - Odontologia | ID: biblio-1132295

RESUMO

Abstract Lateral luxation injuries are one of the most severe periodontal injuries in dental trauma. The correct diagnosis followed by repositioning of the tooth on the right position is fundamental for the periodontal ligament healing. This study reported a clinical case of lateral luxation of maxillary central incisor involving a new cone beam computed tomography (CBCT) software for reconstruction (e-Vol DX) to confirm the lateral luxation after no conclusive dental trauma injury definition by using conventional exam. The lateral luxation injury was digitally reduced by insertion of tooth back to its alveolus, and at the same session, the tooth was stabilized with a rigid splint and further changed to a semi-rigid nylon splint. During the pulpal status monitoring, the pulp was diagnosed necrotic, then the root canal was treated to prevent root resorption. External office-bleaching and restorative procedure was performed. The 4-years follow up and new imaging exam and digital reconstruction confirmed bone healing and no complication. CBCT images analyzed by eVol DX can be used to determine and to guide lateral luxation treatment.


Resumo Lesões de luxação lateral são uma das lesões periodontais mais graves no traumatismo dental. O diagnóstico seguido do reposicionamento do dente na posição correta é fundamental para o reparo do ligamento periodontal. Este estudo relata um caso clínico de luxação lateral do incisivo central superior envolvendo um novo software de reconstrução (e-Vol DX) por tomografia computadorizada de feixe cônico (TCFC) para confirmar a luxação lateral após nenhuma definição de lesão por trauma dental conclusivo pelo exame convencional. A lesão de luxação lateral foi reduzida digitalmente pela inserção do dente de volta ao seu alvéolo e, na mesma sessão, o dente foi estabilizado com uma contenção rígida e posteriormente trocada para uma contenção de nylon semirrígida. Durante o monitoramento da condição pulpar, foi diagnosticada necrose da polpa e, em seguida, o canal radicular foi tratado para evitar a reabsorção radicular. Procedimento externo de clareamento e restauração foi realizado. O acompanhamento de 4 anos e o novo exame de imagem e reconstrução digital não confirmaram reparo ósseo e nenhuma complicação. Imagens de TCFC analisadas pelo e-Vol DX podem ser utilizadas para determinar e orientar lesão de luxação lateral.

11.
Radiat Oncol ; 15(1): 95, 2020 May 06.
Artigo em Inglês | MEDLINE | ID: mdl-32375798

RESUMO

BACKGROUND: Radiotherapy used in tumor treatment compromises vascularization of bone tissue. Hyperbaric oxygenation (HBO) increases oxygen availability and improves vascularization, minimizing the deleterious effects of ionizing radiation (IR). Therefore, the aim of this study was to evaluate HBO therapy effect on bone macroscopy, composition and biomechanical properties after IR damage. METHODS: Twenty male Wistar rats weighing 300 ± 20 g (10 weeks of age) were submitted to IR (30 Gy) to the left leg, where the right leg was not irradiated. After 30 days, ten animals were submitted to HBO therapy, which was performed daily for 1 week at 250 kPa for 90-min sessions. All animals were euthanized 37 days after irradiation and the tibia were separated into four groups (n = 10): from animals without HBO - right tibia Non-irradiated (noIRnoHBO) and left tibia Irradiated (IRnoHBO); and from animals with HBO - right tibiae Non-irradiated (noIRHBO) and left tibia Irradiated (IRHBO). The length (proximal-distal) and thickness (anteroposterior and mediolateral) of the tibiae were measured. Biomechanical analysis evaluated flexural strength and stiffness. Attenuated Total Reflectance Fourier Transform Infrared Spectroscopy (ATR-FTIR) was used to calculate the amide I ratio, crystallinity index, and matrix to mineral ratios. RESULTS: In the macroscopic and ATR-FTIR analysis, the IRnoHBO showed lower values of length, thickness and amide I ratio, crystallinity index and matrix to mineral ratios compared to noIRnoHBO (p < 0.03). IRnoHBO showed no statistical difference compared to IRHBO for these analyses (p > 0.05). Biomechanics analysis showed that the IRnoHBO group had lower values of flexural strength and stiffness compared to noIRnoHBO and IRHBO groups (p < 0.04). In addition, the noIRHBO group showed higher value of flexural strength when compared to noIRnoHBO and IRHBO groups (p < 0.02). CONCLUSIONS: The present study concluded that IR arrests bone development, decreases the collagen maturation and mineral deposition process, thus reducing the flexural strength and stiffness bone mechanical parameters. Moreover, HBO therapy minimizes deleterious effects of irradiation on flexural strength and the bone stiffness analysis.

12.
J Appl Oral Sci ; 28: e20190544, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32348440

RESUMO

Objective To evaluate the influence of three levels of dental structure loss on stress distribution and bite load in root canal-treated young molar teeth that were filled with bulk-fill resin composite, using finite element analysis (FEA) to predict clinical failure. Methodology Three first mandibular molars with extensive caries lesions were selected in teenager patients. The habitual occlusion bite force was measured using gnathodynamometer before and after endodontic/restoration procedures. The recorded bite forces were used as input for patient-specific FEA models, generated from cone-beam computed tomographic (CT) scans of the teeth before and after treatment. Loads were simulated using the contact loading of the antagonist molars selected based on the CT scans and clinical evaluation. Pre and post treatment bite forces (N) in the 3 patients were 30.1/136.6, 34.3/133.4, and 47.9/124.1. Results Bite force increased 260% (from 36.7±11.6 to 131.9±17.8 N) after endodontic and direct restoration. Before endodontic intervention, the stress concentration was located in coronal tooth structure; after rehabilitation, the stresses were located in root dentin, regardless of the level of tooth structure loss. The bite force used on molar teeth after pulp removal during endodontic treatment resulted in high stress concentrations in weakened tooth areas and at the furcation. Conclusion Extensive caries negatively affected the bite force. After pulp removal and endodontic treatment, stress and strain concentrations were higher in the weakened dental structure. Root canal treatment associated with direct resin composite restorative procedure could restore the stress-strain conditions in permanent young molar teeth.


Assuntos
Força de Mordida , Resinas Compostas/química , Resinas Compostas/uso terapêutico , Restauração Dentária Permanente/métodos , Dente Molar , Dente não Vital/terapia , Criança , Força Compressiva , Tomografia Computadorizada de Feixe Cônico , Análise do Estresse Dentário , Módulo de Elasticidade , Análise de Elementos Finitos , Humanos , Modelagem Computacional Específica para o Paciente , Valores de Referência , Reprodutibilidade dos Testes , Resistência à Tração , Dente não Vital/diagnóstico por imagem , Resultado do Tratamento
13.
Braz Dent J ; 31(1): 25-31, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32159701

RESUMO

The purpose of this study was to evaluate the presence of residues after post space preparation (PSP) and establish whether the apical displacement of the gutta-percha was affected by the moments and methods of PSP in teeth filled by the single-cone technique. The root canals of 20 bovine incisor teeth were instrumented with Reciproc and filled with single-cone and AH Plus. The specimens were divided into 4 groups according to the moment and method of PSP (n=5): immediate with drill, immediate with thermoplasticizer, delayed with drill and delayed with thermoplasticizer. Micro-CT scans were performed before and after the PSP for residues of the root canal filling (1) and analysis of apical displacement (2). Data were analyzed by using 2-way repeated measurement ANOVA (1) and 2-way ANOVA (2) followed by the Tukey's test (a=0.05). Significance effect on the residues percentage remaining for methods (p=0.044), for moments (p=0.006), for thirds repetition (p<0.001), and for interaction between methods and thirds (p<0.001), and moments and thirds (p=0.044). Significance effect on the apical displacement of root canal filing was detected for methods (p=0.008), however no difference was found between moments (p=0.617). In general, PSP using drill resulted in more homogeneous root canal preparation, mainly when made immediately. For all other combinations between methods and moments for PSP, the middle and apical thirds presented significant higher residues remaining. Thermo method performed in both moments and the drill method performed immediately had displacement in the apical direction, representing extrusion of the root filling material.


Assuntos
Cavidade Pulpar , Materiais Restauradores do Canal Radicular , Animais , Bovinos , Guta-Percha , Retratamento , Obturação do Canal Radicular , Preparo de Canal Radicular , Microtomografia por Raio-X
14.
Braz Oral Res ; 34: e013, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32074213

RESUMO

This study evaluated the effect of a cyclopentenone-type PG, 15-Deoxy-Δ12,14-PG J2 (15d-PGJ2), and lectin (ScLL) on the viability of human gingival fibroblasts (HGFs), and on IL-6 and TGFß-1 release by these fibroblasts, stimulated with lipopolysaccharide (LPS). HGFs were stimulated with LPS 10 µg/ml and treated with 15d-PGJ2 1 and 2 µg/ml, and ScLL 2 and 5 µg/ml, for 1 and 3h, and then evaluated for viability by MTT assay. Supernatant was collected to detect IL-6 and TGFß-1 release, by ELISA. Positive control was cells kept in Dulbecco's Modified Eagle's Medium, and negative control was those kept in LPS. Data were analyzed by ANOVA and Dunnett's test (α = 0.05). No significant difference was found in viability among experimental groups at 1h (p > 0.05). Percentage of ScLL 5 µg/ml viable cells was similar to that of positive control at evaluated periods (p > 0.05), whereas the other groups had lower levels than the positive control (p < 0.05). IL-6 release was statistically higher for ScLL 5 µg/ml and 15d-PGJ2 2 µg/ml at 1h, compared with the other treated groups and positive control (p < 0.05). No significant differences were found among the groups at 3h (p > 0.05), except for ScLL 2 µg/ml and 15d-PGJ2 1 µg/ml, which showed lower IL-6 release compared with that of negative control (p < 0.05). No significant difference was found among the groups for TGFß-1 release (p > 0.05). Results indicated that ScLL 5 µg/ml did not interfere in viability, and ScLL 2 µg/ml and 15d-PGJ2 1 µg/ml demonstrated reduced IL-6 release. Tested substances had no effect on TGFß-1 release.


Assuntos
Fibroblastos/efeitos dos fármacos , Fibroblastos/metabolismo , Interleucina-6/metabolismo , Lipopolissacarídeos/farmacologia , Lectinas de Plantas/farmacologia , Prostaglandina D2/análogos & derivados , Fator de Crescimento Transformador beta1/metabolismo , Análise de Variância , Sobrevivência Celular/efeitos dos fármacos , Células Cultivadas , Ensaio de Imunoadsorção Enzimática , Gengiva/citologia , Humanos , Prostaglandina D2/farmacologia , Valores de Referência , Estatísticas não Paramétricas , Fatores de Tempo , Fator de Crescimento Transformador beta1/efeitos dos fármacos
15.
Braz. dent. j ; 31(1): 25-31, Jan.-Feb. 2020. tab, graf
Artigo em Inglês | LILACS-Express | LILACS | ID: biblio-1089263

RESUMO

Abstract The purpose of this study was to evaluate the presence of residues after post space preparation (PSP) and establish whether the apical displacement of the gutta-percha was affected by the moments and methods of PSP in teeth filled by the single-cone technique. The root canals of 20 bovine incisor teeth were instrumented with Reciproc and filled with single-cone and AH Plus. The specimens were divided into 4 groups according to the moment and method of PSP (n=5): immediate with drill, immediate with thermoplasticizer, delayed with drill and delayed with thermoplasticizer. Micro-CT scans were performed before and after the PSP for residues of the root canal filling (1) and analysis of apical displacement (2). Data were analyzed by using 2-way repeated measurement ANOVA (1) and 2-way ANOVA (2) followed by the Tukey's test (a=0.05). Significance effect on the residues percentage remaining for methods (p=0.044), for moments (p=0.006), for thirds repetition (p<0.001), and for interaction between methods and thirds (p<0.001), and moments and thirds (p=0.044). Significance effect on the apical displacement of root canal filing was detected for methods (p=0.008), however no difference was found between moments (p=0.617). In general, PSP using drill resulted in more homogeneous root canal preparation, mainly when made immediately. For all other combinations between methods and moments for PSP, the middle and apical thirds presented significant higher residues remaining. Thermo method performed in both moments and the drill method performed immediately had displacement in the apical direction, representing extrusion of the root filling material.


Resumo O objetivo deste estudo foi avaliar a presença de resíduos após o alívio do canal (AC) e verificar se o deslocamento apical da guta-percha foi afetado pelos momentos e métodos de AC em dentes obturados pela técnica do cone único. Os canais radiculares de 20 dentes incisivos bovinos foram instrumentados com Reciproc e obturados com cone único e AH Plus. As amostras foram divididas em 4 grupos de acordo com o momento e método de AC (n=5): broca imediato, termocompactador imediato, broca tardio e termocompactador tardio. Escaneamentos em micro-CT foram realizados antes e após o AC para análise dos resíduos da obturação (1) e do deslocamento apical (2). Os dados foram analisados empregando ANOVA em 2 fatores com medida repetida (1), ANOVA em dois fatores (2), seguidas do teste de Tukey (α=0,05). A porcentagem de resíduos remanescentes foi influenciada pelos métodos (p=0,044), momentos (p=0,006), pelo fator de repetição terços do canal (p<0,001), e pelas interações entre métodos e terços (p<0,001), e momentos e terços (p=0,044). Já para o deslocamento apical da obturação do canal radicular foi detectada influência significativa para os métodos (p=0,008), no entanto, nenhuma diferença foi encontrada entre os momentos (p=0,617). Em geral, AC usando brocas resultou em preparo mais homogêneo dos canais radiculares, principalmente quando realizado imediatamente após a obturação. Para todas as outras combinações entre métodos e momentos de AC, o terço médio e apical apresentaram significativamente maiores resíduos remanescentes. O método termo realizado nos dois momentos e o método broca de preparo realizado imediatamente resultaram em deslocamento na direção apical, representando a extrusão do material de obturação no canal radicular.

16.
Clin Oral Investig ; 24(8): 2763-2771, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31732880

RESUMO

OBJECTIVES: Evaluate the effects of ionizing radiation on microarchitecture, the osteocyte lacunar network, and collagen maturity in a bone repair site. MATERIALS AND METHODS: Bone defects were created on tibias of 20 New Zealand rabbits. After 2 weeks, the animals were randomly divided into (n = 10) NoIr (nonirradiated group) and Ir (irradiated group). In the Ir, the animals received single-dose irradiation of 30 Gy on the tibia and were euthanized after 2 weeks. Bone microarchitecture parameters were analyzed by using micro-CT, and the osteocyte lacunar network, bone matrix, and collagen maturation by histomorphometric analysis. The data were analyzed using unpaired Student's t test (α = 0.05). RESULTS: Trabecular thickness in Ir was lower than that in NoIr (P = 0.028). No difference was found for bone volume fraction and bone area. Lacunae filled with osteocytes were more numerous (P < 0.0001) in NoIr (2.6 ± 0.6) than in Ir (1.97 ± 0.53). Empty lacunae were more prevalent (P < 0.003) in Ir (0.14 ± 0.10) than in NoIr (0.1 ± 0.1). The mean osteocyte lacunae size was higher (P < 0.01) in Ir (15.4 ± 4.41) than in NoIr (12.7 ± 3.7). Picrosirius red analysis showed more (P < 0.05) mature collagen in NoIr (29.0 ± 5.3) than in Ir (23.4 ± 4.5). Immature collagen quantification revealed no difference between groups. CONCLUSIONS: Ionizing radiation compromised bone formation and an impairment in bone repair in irradiated woven bone was observed. CLINICAL RELEVANCE: Before radiotherapy, patients usually need surgical intervention, which may be better performed, if clinicians understand the repair process in irradiated bone, using novel approaches for treating these individuals.


Assuntos
Osteócitos , Animais , Osso e Ossos , Colágeno , Humanos , Coelhos , Radiação Ionizante , Microtomografia por Raio-X
17.
J. appl. oral sci ; 28: e20200191, 2020. tab, graf
Artigo em Inglês | LILACS-Express | LILACS, BBO - Odontologia | ID: biblio-1134799

RESUMO

Abstract Objective: This study analyzed the effect of ionizing radiation on bone microarchitecture and biomechanical properties in the bone tissue surrounding a dental implant. Methodology: Twenty rabbits received three dental morse taper junction implants: one in the left tibia and two in the right tibia. The animals were randomized into two groups: the nonirradiated group (control group) and the irradiated group, which received 30 Gy in a single dose 2 weeks after the implant procedure. Four weeks after the implant procedure, the animals were sacrificed, and the implant/bone specimens were used for each experiment. The specimens (n=10) of the right tibia were examined by microcomputed tomography to measure the cortical volume (CtV, mm3), cortical thickness (CtTh, mm) and porosity (CtPo, %). The other specimens (n=10) were examined by dynamic indentation to measure the elastic modulus (E, GPa) and Vickers hardness (VHN, N/mm2) in the bone. The specimens of the left tibia (n=10) were subjected to pull-out tests to calculate the failure load (N), displacement (mm) up to the failure point and interface stiffness (N/mm). In the irradiated group, two measurements were performed: close, at 1 mm surrounding the implant surface, and distant, at 2.5 mm from the external limit of the first measurement. Data were analyzed using one-way ANOVA, Tukey's test and Student's t-test (α=0.05). Results: The irradiated bone closer to the implant surface had lower elastic modulus (E), Vickers hardness (VHN), Ct.Th, and Ct.V values and a higher Ct.Po value than the bone distant to the implant (P<0.04). The irradiated bone that was distant from the implant surface had lower E, VHN, and Ct.Th values and a higher Ct.Po value than the nonirradiated bone (P<0.04). The nonirradiated bone had higher failure loads, displacements and stiffness values than the irradiated bone (P<0.02). Conclusion: Ionizing radiation in dental implants resulted in negative effects on the microarchitecture and biomechanical properties of bone tissue, mainly near the surface of the implant.

18.
J. appl. oral sci ; 28: e20190544, 2020. tab, graf
Artigo em Inglês | LILACS, BBO - Odontologia | ID: biblio-1101250

RESUMO

Abstract Objective To evaluate the influence of three levels of dental structure loss on stress distribution and bite load in root canal-treated young molar teeth that were filled with bulk-fill resin composite, using finite element analysis (FEA) to predict clinical failure. Methodology Three first mandibular molars with extensive caries lesions were selected in teenager patients. The habitual occlusion bite force was measured using gnathodynamometer before and after endodontic/restoration procedures. The recorded bite forces were used as input for patient-specific FEA models, generated from cone-beam computed tomographic (CT) scans of the teeth before and after treatment. Loads were simulated using the contact loading of the antagonist molars selected based on the CT scans and clinical evaluation. Pre and post treatment bite forces (N) in the 3 patients were 30.1/136.6, 34.3/133.4, and 47.9/124.1. Results Bite force increased 260% (from 36.7±11.6 to 131.9±17.8 N) after endodontic and direct restoration. Before endodontic intervention, the stress concentration was located in coronal tooth structure; after rehabilitation, the stresses were located in root dentin, regardless of the level of tooth structure loss. The bite force used on molar teeth after pulp removal during endodontic treatment resulted in high stress concentrations in weakened tooth areas and at the furcation. Conclusion Extensive caries negatively affected the bite force. After pulp removal and endodontic treatment, stress and strain concentrations were higher in the weakened dental structure. Root canal treatment associated with direct resin composite restorative procedure could restore the stress-strain conditions in permanent young molar teeth.


Assuntos
Humanos , Criança , Força de Mordida , Resinas Compostas/química , Dente não Vital/terapia , Restauração Dentária Permanente/métodos , Dente Molar , Valores de Referência , Resistência à Tração , Reprodutibilidade dos Testes , Resultado do Tratamento , Resinas Compostas/uso terapêutico , Dente não Vital/diagnóstico por imagem , Força Compressiva , Análise de Elementos Finitos , Análise do Estresse Dentário , Tomografia Computadorizada de Feixe Cônico , Módulo de Elasticidade , Modelagem Computacional Específica para o Paciente
19.
Braz. oral res. (Online) ; 34: e013, 2020. graf
Artigo em Inglês | LILACS-Express | LILACS | ID: biblio-1089379

RESUMO

Abstract This study evaluated the effect of a cyclopentenone-type PG, 15-Deoxy-Δ12,14-PG J2 (15d-PGJ2), and lectin (ScLL) on the viability of human gingival fibroblasts (HGFs), and on IL-6 and TGFβ-1 release by these fibroblasts, stimulated with lipopolysaccharide (LPS). HGFs were stimulated with LPS 10 μg/ml and treated with 15d-PGJ2 1 and 2 μg/ml, and ScLL 2 and 5 μg/ml, for 1 and 3h, and then evaluated for viability by MTT assay. Supernatant was collected to detect IL-6 and TGFβ-1 release, by ELISA. Positive control was cells kept in Dulbecco's Modified Eagle's Medium, and negative control was those kept in LPS. Data were analyzed by ANOVA and Dunnett's test (α = 0.05). No significant difference was found in viability among experimental groups at 1h (p > 0.05). Percentage of ScLL 5 µg/ml viable cells was similar to that of positive control at evaluated periods (p > 0.05), whereas the other groups had lower levels than the positive control (p < 0.05). IL-6 release was statistically higher for ScLL 5 μg/ml and 15d-PGJ2 2 µg/ml at 1h, compared with the other treated groups and positive control (p < 0.05). No significant differences were found among the groups at 3h (p > 0.05), except for ScLL 2 µg/ml and 15d-PGJ2 1 µg/ml, which showed lower IL-6 release compared with that of negative control (p < 0.05). No significant difference was found among the groups for TGFβ-1 release (p > 0.05). Results indicated that ScLL 5 μg/ml did not interfere in viability, and ScLL 2 µg/ml and 15d-PGJ2 1 µg/ml demonstrated reduced IL-6 release. Tested substances had no effect on TGFβ-1 release.

20.
Braz Dent J ; 30(5): 491-497, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31596334

RESUMO

The aim of this study was to evaluate the effect of magnification during post space preparation on root cleanness and on fiber post bond strength. Methods: Thirty human central upper incisors with similar root canal in size and shape were selected, decoronated to 15 mm and endodontically filled. The teeth were assigned into 3 groups (n=10), according to the method of magnification during post space preparation inspection: Control, using naked eye; loupe, using a dental surgical 3x magnifying glass; surgical microscope, using a 6x surgical microscope. The roots were scanned by using micro-CT before and after post space preparation for residue remnants evaluation. Fiber posts were cemented using self-adhesive resin cement (Rely X U200, 3M-ESPE). Two 1-mm-thick slices from the cervical, medium and apical thirds were submitted to a push-out test (PBS). Failures modes were classified. PBS data were analyzed by using two-way ANOVA with repeated measurement and the Tukey test. The significance level was set at 5%. The method of visualization had no effect on PBS (p=0.556). The cervical region had higher values than apical region irrespective of the inspection method (p=0.012). Adhesive failure between the resin cement and dentin was the prevalent failure mode for all groups. Micro-CT analysis showed no difference on root cleanness into the root canal after post space preparation. The use of magnification devices as loupe and microscope while performing post space do not improve the PBS and did not affect sealer remain of decoronated anterior teeth.


Assuntos
Colagem Dentária , Técnica para Retentor Intrarradicular , Cavidade Pulpar , Dentina , Adesivos Dentinários , Humanos , Teste de Materiais , Cimentos de Resina
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