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1.
Biomed Mater Eng ; 30(2): 145-156, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30741663

RESUMO

BACKGROUND: Human dentin is a highly calcified tissue of mesenchymal origin with a heterogeneous structure. Its morphology is constantly remodelled throughout the life span of the tooth, as well as under the influence of external stimuli. OBJECTIVE: The aim of the present study was to obtain information about the thermal changes in the crown and root dentin specimens of vital and devitalized teeth. METHODS: The investigated samples were divided into 6 groups, depending on the patients' age and dentin location (crown, root). An additional group of endodontically treated teeth was created. The methods of choice were were combined thermal analysis (DTA-TG(DTG)-MS and gas chromatography-mass spectrometry. RESULTS: After heating up to 1200 °C, endo- and exothermal effects were observed. The effects' dynamic was the same for all samples. The differences were in the samples' weight after the experiment, with root dentin showing the greatest mass loss percentage. CONCLUSIONS: The observed mass loss differences could be attributed to the presence of impurities in the dentin, as well as alterations in the collagen matrix. Ageing and endodontic treatment could catalyse the accumulation of such changes and affect the microstructure of the mineralized tissue.


Assuntos
Envelhecimento , Dentina/fisiologia , Dentina/fisiopatologia , Dente não Vital/fisiopatologia , Adulto , Temperatura Alta , Humanos , Coroa do Dente/fisiologia , Coroa do Dente/fisiopatologia , Raiz Dentária/fisiologia , Raiz Dentária/fisiopatologia
2.
J Endod ; 45(2): 136-143, 2019 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-30711168

RESUMO

INTRODUCTION: Histologic examination of teeth after regenerative endodontic treatment (RET) shows that the type, quality, and quantity of tissues formed in the root canal space are not predictable. The aim of this study was to examine clinically, radiographically, and histologically the outcome of RET in immature noninfected human teeth using SynOss Putty (Collagen Matrix Inc, Oakland, NJ) as a scaffold. METHODS: Three pairs of maxillary/mandibular first premolars in 3 patients scheduled for extraction were included. Sensibility tests confirmed the presence of vital pulps. After informed consent, anesthesia, and rubber dam isolation, the pulps were removed. RET was performed using the following scaffolds: SynOss Putty + blood in both teeth in patient #1, SynOss Putty with or without blood in patient #2, and SynOss Putty + blood or blood only in patient #3. After a follow-up period of 2.5-7.5 months, the teeth were clinically and radiographically evaluated, extracted, and examined histologically. RESULTS: Patients remained asymptomatic after treatment. Radiographic examination of the teeth showed signs of root development after treatment. In teeth treated with SynOss Putty + blood, histologic examination showed formation of intracanal mineralized tissue around the scaffold particles solidifying with newly formed cementumlike tissue on the dentinal walls. The tooth treated with SynOss Putty without blood showed the formation of a periapical lesion. The tooth treated with a blood clot only showed tissues of periodontal origin growing into the root canal space. CONCLUSIONS: SynOss Putty + blood showed a predictable pattern of tissue formation and mineralization when used as a scaffold for RET in human immature noninfected teeth. The newly formed mineralized tissue solidifies with newly formed cementum on the dentinal walls.


Assuntos
Colágeno , Cavidade Pulpar/fisiologia , Dentina/fisiologia , Durapatita , Regeneração Tecidual Guiada Periodontal/métodos , Radiografia Dentária , Regeneração , Endodontia Regenerativa/métodos , Tecidos Suporte , Raiz Dentária/fisiologia , Dente não Vital/diagnóstico por imagem , Dente não Vital/patologia , Criança , Cavidade Pulpar/diagnóstico por imagem , Dentina/diagnóstico por imagem , Feminino , Humanos , Masculino , Raiz Dentária/diagnóstico por imagem , Dente não Vital/fisiopatologia , Resultado do Tratamento
3.
J Endod ; 44(10): 1517-1525, 2018 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-30144988

RESUMO

INTRODUCTION: A regenerative endodontic procedure (REP) is a biologically based treatment to functionally replace the pulp of infected immature permanent teeth. The purpose of this retrospective case series was to assess the outcome of REPs of infected immature permanent teeth in terms of periapical bone healing (PBH), root development (RD), and pulp vitality. METHODS: Five patients (1 tooth/patient) who had undergone a REP based on the cell homing concept were recalled 3, 6, 12, 24, and 36 months postoperatively. At each recall session, clinical and periapical radiographic (PR) investigations were performed. Cone-beam computed tomographic (CBCT) imaging was taken before and 36 months after REPs. Qualitative and quantitative PR assessments were performed on the teeth that underwent REPs. Quantitative CBCT analyses were performed on the teeth that underwent REP and contralateral teeth. RESULTS: At each recall session, all teeth were asymptomatic but reacted negatively on carbon dioxide snow and electrical pulp testing. All teeth that underwent a REP showed complete PBH and further RD on PR and CBCT assessments when comparing the baseline with the final recall radiographs. CBCT analyses indicated increases in root hard tissue volume and RL for all teeth that underwent a REP, but they were 5 and 3 times less, respectively, than the contralateral teeth. The postoperative CBCT images presented bone ingrowth inside the root canal, calcification, or nonuniform RD. CONCLUSIONS: Thirty-six months after the REPs (based on the cell homing concept), this RCS resulted radiographically and clinically in functional and asymptomatic teeth with complete PBH and continued reparative RD. CBCT quantitative measurements and qualitative root development observations are more reliable and accurate than PR analysis.


Assuntos
Tomografia Computadorizada de Feixe Cônico , Imagem Tridimensional , Radiografia Dentária , Endodontia Regenerativa/métodos , Dente não Vital/diagnóstico por imagem , Dente não Vital/fisiopatologia , Criança , Polpa Dentária/fisiologia , Feminino , Humanos , Masculino , Estudos Retrospectivos , Ápice Dentário/fisiologia , Raiz Dentária/crescimento & desenvolvimento , Resultado do Tratamento
4.
Niger J Clin Pract ; 21(6): 795-800, 2018 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-29888730

RESUMO

Objective: This study aimed to evaluate the effects of different coronal restoration techniques on fracture resistance of root canal-treated mandibular premolars with mesio-occluso-distal (MOD) cavities. Materials and Methods: A total of 105 mandibular premolars were selected and randomly distributed into seven groups (n = 15). MOD cavities were prepared except the control group. Root canal treatments were performed. Each tooth was embedded in acrylic resin. Groups were classified as follows; G1: intact teeth (control), G2: unfilled MOD cavity, G3: MOD + composite resin, G4: 10-mm-long fiber post + composite resin, G5: 5-mm-long fiber post + composite resin, G6: Ribbond in the occlusal surface + composite resin, and G7: horizontal fiber post + composite resin. Specimens were loaded using a universal testing machine until fracture occurs. Fracture loads were recorded and statistical interpretations were made (α = 0.05). Results: In Groups 1, 6, and 7, the greatest fracture resistance was shown and there were no significant differences among these groups (P > 0.05). No significant differences were detected among the Groups 3, 4, and 5 (P > 0.05), whereas the fracture resistances of Groups 1, 6, and 7 were significantly greater than these three groups (P < 0.05). Group 2 had the lowest fracture resistance of all groups (P < 0.05). Conclusion: Usage of horizontal post or occlusal Ribbond usage increased the fracture resistance of root canal-treated premolars with MOD cavities.


Assuntos
Dente Pré-Molar/fisiopatologia , Materiais Dentários/química , Tratamento do Canal Radicular/métodos , Fraturas dos Dentes/fisiopatologia , Dente não Vital/fisiopatologia , Resinas Compostas/química , Cavidade Pulpar/lesões , Humanos , Polietilenos , Cimentos de Resina/química , Estresse Mecânico , Dente não Vital/terapia , Resultado do Tratamento
5.
Med Hypotheses ; 115: 35-41, 2018 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-29685193

RESUMO

The prognosis of endodontically treated teeth has traditionally been associated with the presence of the so-called ferrule effect that is generally related with the presence of a minimum of 1-2 mm of sound tooth structure at the cervical area of parallel axial walls that totally encircle the tooth. Even though all of these factors are well desired, one should question if their absence should condemn a tooth and compel extraction as the only logical treatment plan option. For this reason an hypothesis is being formed that associates the aforementioned factors not with the presence of the so-called ferrule effect, but rather with the resistance form of the preparation that is being provided by the sound tooth structure at the cervical area of the tooth. When the desired resistance form is provided by sound tooth structure of endodontically treated teeth, then less lateral forces are being transferred to the post & core and subsequently to the root of the teeth, thus minimizing the chances of decementation of the post & core or worst fracture of the root. Even more important, if this hypothesis may be further entertained, then even when the so-called ferrule effect is not present, the teeth may not be extracted, but alternative strategies for post & core restorations may be investigated, such a more flexible carbon- or glass-fiber posts & core build ups made from flowable resin composite that may accommodate for the increased lateral forced exerted to the post & core complex during function.


Assuntos
Modelos Dentários , Dente não Vital , Resinas Compostas , Humanos , Técnica para Retentor Intrarradicular , Prognóstico , Dente não Vital/patologia , Dente não Vital/fisiopatologia , Dente não Vital/terapia
6.
J Endod ; 44(4): 659-664, 2018 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-29459151

RESUMO

INTRODUCTION: Pericervical dentin (PCD) loss may increase root fracture propensity in root-filled teeth. This study evaluated the impacts of bonding PCD with composite resin (CR) on radicular microstrain distribution and load at failure of root-filled maxillary premolars. METHODS: Ten single-canal maxillary premolars decoronated 2 mm coronal to the cementoenamel junction (CEJ) had canals enlarged with ProTaper Universal instruments (Dentsply Tulsa Dental Specialties, Tulsa, OK) to F3. They were root filled with gutta-percha (GP) to the CEJ and restored with Cavit (3M Deutschland GmbH, Neuss, Germany) (GP group, n = 5) or 6 mm apical to the CEJ and restored with bonded CR to simulate bonding of PCD (bonded PCD group, n = 5). Digital moiré interferometry was used to evaluate pre- and postoperative whole-field microstrain distribution in the root dentin under physiologically relevant loads (10-50 N). Another 30 premolars, similarly treated as groups 1 and 2 or left untreated as controls (n = 10/group), were subjected to cyclic loads (1.2 million cycles, 45 N, 4 Hz) followed by uniaxial compressive load to failure. Mechanical data were analyzed with 1-way analysis of variance and the post hoc Tukey test at a 5% level of significance. RESULTS: Microstrain distribution showed bending and compressive patterns at the coronal and apical root dentin, respectively. In the GP group, microstrain distribution was unaltered. In the bonded-PCD group, different microstrain distribution suggested stiffening at the PCD. The load at failure did not differ significantly for the GP, bonded PCD, and control groups (P > .05). CONCLUSIONS: CR bonding of PCD might impact the biomechanical responses in maxillary premolar roots at low-level continuous loads. The effect of this impact on root fracture loads when subjected to cyclic load warrants further investigation.


Assuntos
Dente Pré-Molar/fisiologia , Colagem Dentária/efeitos adversos , Dentina/fisiologia , Dente não Vital/fisiopatologia , Fenômenos Biomecânicos , Resinas Compostas/efeitos adversos , Resinas Compostas/uso terapêutico , Análise do Estresse Dentário , Humanos , Maxila , Tratamento do Canal Radicular/efeitos adversos , Tratamento do Canal Radicular/métodos , Fraturas dos Dentes/etiologia , Fraturas dos Dentes/prevenção & controle
7.
Braz Dent J ; 28(6): 715-719, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-29211127

RESUMO

This study evaluated the stress distribution in endodontically treated teeth, weakened (W) or not weakened (NW), restored with different materials of prosthetic crown using 3D-FEA. Models of a maxillary canine were constructed based on micro-CT images and divided into the groups: G1 (control) - sound tooth; G2 to G7 - endodontically treated teeth restored with glass fiber post (GFP); which G2 to G4 simulated NW root and G5 to G7 simulated W root. For crown material the teeth were restored with: G2 and G5: metallic coping and ceramic veneering, G3 and G6: zirconia coping and ceramic veneering, G4 and G7: alumina coping and ceramic veneering. Load of 180 N was applied at the incisal third of lingual surface at 45º. Models were supported by the periodontal ligament (x=y=z=0). The von Mises stress (VMS) values were calculated. The W teeth presented higher VMS at coping when compared to NW teeth and group G1 showed lower VMS value. For crown material, for both W or NW teeth, increasing VMS was found at metallic, zirconia and alumina coping, respectively. Metallic coping showed a better performance despite its unfavorable esthetics, suggesting as an appropriate material for prosthetic restoration of endodontically treated teeth.


Assuntos
Coroas , Análise do Estresse Dentário , Teste de Materiais , Dente não Vital/fisiopatologia , Análise de Elementos Finitos , Humanos , Dente não Vital/terapia
8.
Braz. dent. j ; 28(6): 715-719, Nov.-Dec. 2017. tab, graf
Artigo em Inglês | LILACS | ID: biblio-888707

RESUMO

Abstract This study evaluated the stress distribution in endodontically treated teeth, weakened (W) or not weakened (NW), restored with different materials of prosthetic crown using 3D-FEA. Models of a maxillary canine were constructed based on micro-CT images and divided into the groups: G1 (control) - sound tooth; G2 to G7 - endodontically treated teeth restored with glass fiber post (GFP); which G2 to G4 simulated NW root and G5 to G7 simulated W root. For crown material the teeth were restored with: G2 and G5: metallic coping and ceramic veneering, G3 and G6: zirconia coping and ceramic veneering, G4 and G7: alumina coping and ceramic veneering. Load of 180 N was applied at the incisal third of lingual surface at 45º. Models were supported by the periodontal ligament (x=y=z=0). The von Mises stress (VMS) values were calculated. The W teeth presented higher VMS at coping when compared to NW teeth and group G1 showed lower VMS value. For crown material, for both W or NW teeth, increasing VMS was found at metallic, zirconia and alumina coping, respectively. Metallic coping showed a better performance despite its unfavorable esthetics, suggesting as an appropriate material for prosthetic restoration of endodontically treated teeth.


Resumo Este estudo avaliou a distribuição de tensão em dentes tratados endodonticamente, fragilizados (F) ou não fragilizados (NF), restaurados com diferentes materiais para a coroa protética utilizando 3D-FEA. Modelos de um canino maxilar foram construídos baseados em imagens de micro-CT e divididos em grupos: G1 (controle) - dente hígido; G2 a G7 - dentes tratados endodonticamente com pino de fibra de vidro (PFV), sendo que G2 a G4 simularam raízes NF e G5 a G7 simularam raízes F. Para o material das coroas os dentes foram restaurados com: G2 e G5: coping metálico e revestimento cerâmico, G3 e G6: coping de zirconia e revestimento cerâmico, G4 e G7: coping de alumina e revestimento cerâmico. Carregamento de 180 N foi aplicado na superfície lingual em seu terço incisal com 45 graus de inclinação. Os modelos foram suportados pelo ligamento periodontal (x=y=z=0). Os valores da tensão de von Mises (VMS) foram calculados. Os dentes F apresentaram maiores valores VMS para o coping quando comparados aos dentes NF, sendo que o G1 apresentou menores valores VMS. Para o material das coroas, ambos F ou NF aumentaram VMS no coping metálico, zirconia e alumina, respectivamente. Copings metálicos apresentaram melhor comportamento mecânico apesar de não favorecerem a estética, o que sugere ser um material apropriado para a restauração de dentes tratados endodonticamente.


Assuntos
Humanos , Coroas , Análise do Estresse Dentário , Dente não Vital/fisiopatologia , Análise de Elementos Finitos , Dente não Vital/terapia
9.
Dent Mater ; 33(12): 1466-1472, 2017 12.
Artigo em Inglês | MEDLINE | ID: mdl-29126633

RESUMO

OBJECTIVE: To assess the effect of a ferrule design with specific post material-shape combinations on the mechanical behavior of post-restored canine teeth. METHODS: Micro-CT scan images of an intact canine were used to create a 3-D tessellated CAD model, from which the shapes of dentin, pulp and enamel were obtained and geometric models of post-endodontically restored teeth were created. Two types of 15mm post were evaluated: a quartz fiber post with conical-tapered shape, and a carbon (C) fiber post with conical-cylindrical shape. The abutment was created around the coronal portion of the posts and 0.1mm cement was added between prepared crown and abutment. Cement was also added between the post and root canal and a 0.25mm periodontal ligament was modeled around the root. Four models were analysed by Finite Element (FE) Analysis: with/without a ferrule for both types of post material and shape. A load of 50N was applied at 45° to the longitudinal axis of the tooth, acting on the palatal surface of the crown. The maximum normal stress criterion was adopted as a measure of potential damage. RESULTS: Models without a ferrule showed greater stresses (16.3MPa) than those for models with a ferrule (9.2MPa). With a ferrule, stress was uniformly distributed along the abutment and the root, with no critical stress concentration. In all models, the highest stresses were in the palatal wall of the root. Models with the C-fiber post had higher stress than models with the quartz fiber posts. The most uniform stress distribution was with the combination of ferrule and quartz fiber post. SIGNIFICANCE: The FE analysis confirmed a beneficial ferrule effect with the combination of ferrule and quartz fiber post, with tapered shape, affording no critical stress concentrations within the restored system.


Assuntos
Coroas , Dente Canino/fisiologia , Tratamento do Canal Radicular , Dente não Vital/fisiopatologia , Projeto Auxiliado por Computador , Dente Canino/diagnóstico por imagem , Dente Suporte , Materiais Dentários/química , Planejamento de Prótese Dentária , Análise de Elementos Finitos , Humanos , Imagem Tridimensional , Teste de Materiais , Técnica para Retentor Intrarradicular , Dente não Vital/diagnóstico por imagem , Microtomografia por Raio-X
10.
Oper Dent ; 42(6): 646-657, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-28976843

RESUMO

OBJECTIVES: To evaluate the effects of direct composite resin without a post or with one or two fiberglass posts on the restoration of severely compromised endodontically treated molars. METHODS AND MATERIALS: Forty-five molars with 2 mm of "remaining tooth structure" were divided into three groups: Wfgp, restored with Filtek Z350XT without a fiberglass post; 1fgp, restored with Z350XT with one fiberglass post in the distal root canal; and 2fgp, restored with Z350XT with two fiberglass posts, one in the distal root canal and the other in the mesial-buccal root canal. The teeth were load cycled. Tooth remaining strain was measured using strain gauges (n=10) at two moments: TrSt-100 N, during 100 N occlusal loading, and TrSt-Fr, at fracture load. Fracture resistance was calculated, and fracture mode was classified. The elastic modulus and Vickers hardness were calculated using dynamic indentation (n=5). Stress distribution was analyzed by three-dimensional finite element analysis. RESULTS: The use of two fiberglass posts resulted in lower fracture resistance than was noted in the groups with one fiberglass post and without fiberglass posts. The lingual surface of the remaining tooth had higher strain values than the buccal surface, regardless of the restorative technique and moment of evaluation. The absence of a fiberglass post resulted in significantly higher strain values and more irreparable fracture modes than were noted in the other groups. The use of one fiberglass post had a better strain/fracture resistance ratio. Stresses were concentrated in the occlusal portion of the post and in the furcation region. The presence of one fiberglass post resulted in better stress distribution in the entire distal root dentin, reducing stress on the critical areas. CONCLUSIONS: The use of one fiberglass post for restoring molars with direct composite resin resulted in higher fracture resistance than did the use of two fiberglass posts; it also resulted in better tooth remaining strain and stress distribution and more reparable fracture modes than were seen in the group without a fiberglass post.


Assuntos
Resinas Compostas/uso terapêutico , Restauração Dentária Permanente/métodos , Dente Molar/fisiopatologia , Técnica para Retentor Intrarradicular , Dente não Vital/fisiopatologia , Falha de Restauração Dentária , Restauração Dentária Permanente/efeitos adversos , Análise do Estresse Dentário , Humanos , Técnicas In Vitro , Técnica para Retentor Intrarradicular/efeitos adversos , Fraturas dos Dentes/etiologia , Fraturas dos Dentes/prevenção & controle
11.
J Appl Oral Sci ; 25(5): 465-476, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-29069143

RESUMO

Tissue repair is an essential process that reestablishes tissue integrity and regular function. Nevertheless, different therapeutic factors and clinical conditions may interfere in this process of periapical healing. This review aims to discuss the important therapeutic factors associated with the clinical protocol used during root canal treatment and to highlight the systemic conditions associated with the periapical healing process of endodontically treated teeth. The antibacterial strategies indicated in the conventional treatment of an inflamed and infected pulp and the modulation of the host's immune response may assist in tissue repair, if wound healing has been hindered by infection. Systemic conditions, such as diabetes mellitus and hypertension, can also inhibit wound healing. The success of root canal treatment is affected by the correct choice of clinical protocol. These factors are dependent on the sanitization process (instrumentation, irrigant solution, irrigating strategies, and intracanal dressing), the apical limit of the root canal preparation and obturation, and the quality of the sealer. The challenges affecting the healing process of endodontically treated teeth include control of the inflammation of pulp or infectious processes and simultaneous neutralization of unpredictable provocations to the periapical tissue. Along with these factors, one must understand the local and general clinical conditions (systemic health of the patient) that affect the outcome of root canal treatment prediction.


Assuntos
Tecido Periapical/fisiopatologia , Tratamento do Canal Radicular/métodos , Dente não Vital/fisiopatologia , Dente não Vital/terapia , Cicatrização/fisiologia , Cimentos para Ossos/uso terapêutico , Hidróxido de Cálcio/uso terapêutico , Humanos , Periodontite Periapical/terapia , Materiais Restauradores do Canal Radicular/uso terapêutico , Irrigantes do Canal Radicular/uso terapêutico , Resultado do Tratamento
12.
J. appl. oral sci ; 25(5): 465-476, Sept.-Oct. 2017. graf
Artigo em Inglês | LILACS | ID: biblio-893653

RESUMO

Abstract Tissue repair is an essential process that reestablishes tissue integrity and regular function. Nevertheless, different therapeutic factors and clinical conditions may interfere in this process of periapical healing. This review aims to discuss the important therapeutic factors associated with the clinical protocol used during root canal treatment and to highlight the systemic conditions associated with the periapical healing process of endodontically treated teeth. The antibacterial strategies indicated in the conventional treatment of an inflamed and infected pulp and the modulation of the host's immune response may assist in tissue repair, if wound healing has been hindered by infection. Systemic conditions, such as diabetes mellitus and hypertension, can also inhibit wound healing. The success of root canal treatment is affected by the correct choice of clinical protocol. These factors are dependent on the sanitization process (instrumentation, irrigant solution, irrigating strategies, and intracanal dressing), the apical limit of the root canal preparation and obturation, and the quality of the sealer. The challenges affecting the healing process of endodontically treated teeth include control of the inflammation of pulp or infectious processes and simultaneous neutralization of unpredictable provocations to the periapical tissue. Along with these factors, one must understand the local and general clinical conditions (systemic health of the patient) that affect the outcome of root canal treatment prediction.


Assuntos
Humanos , Tecido Periapical/fisiopatologia , Tratamento do Canal Radicular/métodos , Cicatrização/fisiologia , Dente não Vital/fisiopatologia , Dente não Vital/terapia , Periodontite Periapical/terapia , Materiais Restauradores do Canal Radicular/uso terapêutico , Irrigantes do Canal Radicular/uso terapêutico , Cimentos para Ossos/uso terapêutico , Hidróxido de Cálcio/uso terapêutico , Resultado do Tratamento
13.
J Endod ; 43(6): 871-875, 2017 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-28359663

RESUMO

INTRODUCTION: Decreased sensitivity to occlusal load could lead to a greater risk of damage to endodontically treated teeth. Therefore, this study aims to test whether root canal treatment reduces the sensitivity of the treated teeth to occlusal load. METHODS: This is a comparative cross-sectional study of 124 patients who received root canal treatment. Treated teeth were compared with vital teeth on the contralateral side. After interviews with participants, their maximal bite forces (MBFs) of their root canal-treated and contralateral untreated teeth were measured using a digital bite fork force transducer. Data were analyzed by comparing the mean MBF of root canal-treated and control teeth. RESULTS: The mean MBF (± standard deviation) was 226.6 N (±168.7) for root canal-treated teeth and 207.93 N (±158.08) for control teeth. Root canal-treated teeth had a significantly higher difference in the mean MBF than the control group (P < .0001) using the paired sample t test. A univariate analysis test showed that differences in the MBF were affected by molar relationship, overbite, and the quality of root filling. CONCLUSIONS: The difference in the MBF was significantly higher in root canal-treated teeth, which is consistent with the function of dental pulp as a highly sensitive sensor. Therefore, the reduction in the sensitivity of teeth to an applied load after pulp removal may increase the risk of overloading. This may, in turn, increase the frequency of tooth damage after root canal treatment.


Assuntos
Força de Mordida , Dente não Vital/fisiopatologia , Dente/fisiologia , Adolescente , Adulto , Estudos Transversais , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Tratamento do Canal Radicular/efeitos adversos , Adulto Jovem
14.
J Endod ; 43(5): 791-795, 2017 May.
Artigo em Inglês | MEDLINE | ID: mdl-28343925

RESUMO

INTRODUCTION: In order to understand the mechanical behavior of a weakened incisor, this study aimed to evaluate the stress distribution caused by different alveolar bone heights and cement layer thickness. METHODS: A finite element analysis was conducted for this investigation. An intact maxillary central incisor was initially modeled, and the bone of the models was modified in order to simulate 4 levels of bone height: BL0 (no bone loss), BL1 (1/3 bone loss), BL2 (1/2 bone loss), and BL3 (2/3 bone loss). These teeth models were remodeled with a fiber post at 2 different cement thicknesses and restored with a ceramic crown; "A" refers to the well-adapted fiber post (0.3 mm) and "B" to the nonadapted fiber post (1 mm), resulting in 12 models. RelyX ARC (3M ESPE, St Paul, MN) cement was simulated for the cementation of the crowns and fiber posts for all groups. Numeric models received a load of 100 N on the lingual surface. All materials and structures were considered linear elastic, homogeneous, and isotropic. Numeric models were plotted and meshed with isoparametric elements, and results were expressed in maximum principal stress. RESULTS: For fiberglass posts, cement, and dentin, the highest stress concentration occurred in the groups with increased bone loss. For cortical bone, the highest values were for the groups with 1/3 bone loss. A greater thickness of cement layer concentrates more stress. CONCLUSIONS: More bone loss and greater CLT were the influential factors in concentrating the stress.


Assuntos
Perda do Osso Alveolar/cirurgia , Cimentos Dentários/uso terapêutico , Incisivo/cirurgia , Dente não Vital/fisiopatologia , Perda do Osso Alveolar/fisiopatologia , Fenômenos Biomecânicos , Força Compressiva , Cimentos Dentários/efeitos adversos , Análise do Estresse Dentário , Análise de Elementos Finitos , Humanos , Imagem Tridimensional , Incisivo/fisiopatologia , Maxila , Resistência à Tração
15.
Aust Endod J ; 43(3): 115-122, 2017 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-27885743

RESUMO

The aim of this study was to investigate (i) the effect of direct or indirect polymerisation of adhesive-impregnated ribbon fibre under 4-mm bulk-filled composites on fracture strength; (ii) to compare polyethylene ribbon fibre-reinforcement composites with short fibre-reinforced composite; and (iii) the effectiveness of polyethylene ribbon fibre according to the restorative materials used (low-viscous bulk-fill composite, high-viscous flowable composite or conventional paste composite). Seventy molars were divided into seven groups; (groups 1-2) Ribbond-reinforced Surefil-SDR; (group 3) Ribbond-reinforced G Aenial Flo; (group 4) Ribbond-reinforced G Aenial Posterior; (group 5) short fibre-reinforced composite everX Posterior; (group 6) unfilled cavity; (group 7) intact teeth. Ribbond was adopted to cavity walls by impregnating an adhesive and using a flowable composite. In group 1, adhesive-impregnated Ribbond was polymerised directly using a light-curing-unit, and indirectly in group 2 under 4-mm bulk-filled composite. Direct or indirect polymerisation of adhesive impregnated ribbon fibre under 4-mm bulk-filled composite did not change the fracture strength results. Polyethylene ribbon fibre-reinforced groups (groups 1-4) and short fibre-reinforced composite group (group 5) displayed similar results. Polyethylene ribbon fibre can be used safely under 4-mm bulk-filled composites. Ribbond-reinforced low-viscous bulk-fill, high-viscous flowable, and conventional paste composite exhibited similar fracture strength results.


Assuntos
Materiais Dentários/química , Análise do Estresse Dentário , Fraturas dos Dentes/fisiopatologia , Dente não Vital/fisiopatologia , Resinas Compostas , Restauração Dentária Permanente/métodos , Resistência à Flexão , Humanos , Microscopia Eletrônica de Varredura , Dente Molar/patologia , Dente Molar/ultraestrutura , Polietilenos , Tratamento do Canal Radicular/métodos , Fraturas dos Dentes/patologia
16.
Acta Odontol Scand ; 74(5): 411-5, 2016 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-27140658

RESUMO

OBJECTIVE: Evaluation of pulp vitality is an important diagnostic procedure in dentistry. Conventional techniques for measurement of pulp vitality, including thermal stimulation, electrical stimulation, or direct dentin stimulation, are frequently associated with false positive or false negative results. Recently, oxygen saturation from pulse oximetry has been utilized in the evaluation of pulp vitality. Perfusion index (PI) data calculated from photoplethysmography have been widely used to evaluate peripheral perfusion. The combination of oxygen saturation and PI may aid in the accurate measurement of pulp vitality. We aimed to investigate the baseline values of oxygen saturation and PI using pulse oximetry in adult volunteers. MATERIAL AND METHODS: Fifteen adult volunteers with viable incisors were tested. To measure PI, a fabricated oxygen sensor was applied to an incisor without a pulp lesion while oxygen saturation was simultaneously measured in the finger. Oxygen saturation and PI were continuously measured with customized software. The normal reference values of oxygen saturation and PI were obtained by analyzing the recorded data. RESULTS: Pulse oximetry showed relatively stable, objective, and accurate oxygen saturation results. The tooth oxygen saturation ranged from 97% to 100%. The PI ranged from 0.3% to 0.5%, and PI and oxygen saturation showed relatively consistent values across subjects. CONCLUSIONS: Although there are some limitations to our study, these results may prove useful for detecting teeth with impaired vitality and non-invasively differentiating between necrotic and vital pulp.


Assuntos
Teste da Polpa Dentária/métodos , Polpa Dentária/irrigação sanguínea , Incisivo/irrigação sanguínea , Oximetria/métodos , Adulto , Temperatura Baixa , Teste da Polpa Dentária/instrumentação , Estimulação Elétrica/métodos , Humanos , Oximetria/instrumentação , Oxigênio/sangue , Fotopletismografia/métodos , Valores de Referência , Fluxo Sanguíneo Regional/fisiologia , Dente não Vital/fisiopatologia , Adulto Jovem
17.
Am J Orthod Dentofacial Orthop ; 149(1): 84-91, 2016 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-26718382

RESUMO

INTRODUCTION: There is a lack of research to support the belief that root canal treatment can be considered for stopping or decreasing external apical root resorption (EARR). There is conflicting evidence as to whether root-filled teeth are more or less likely to experience EARR after orthodontic treatment. The purpose of this study was to compare the degree of EARR of root-filled teeth with that of contralateral teeth with vital pulp after fixed orthodontic treatment. METHODS: The study sample consisted of 35 patients aged 25.23 ± 4.92 years who had at least 1 root-filled tooth before orthodontic treatment. Digital panoramic radiographs of each patient taken before and after orthodontic treatment were used to measure the EARR. The Student t test for matched pairs and the Pearson correlation analysis were applied. RESULTS: The mean EARR values were 0.22 (0.14, 0.35) for root-filled teeth and 0.87 (0.59, 1.31) for contralateral teeth with vital pulp, indicating significantly less EARR for root-filled teeth compared with the contralateral teeth with vital pulp after orthodontic treatment. EARR was influenced by the patient's age, treatment duration, treatment type, and periapical pathosis, but not by tooth type and sex. CONCLUSIONS: Root-filled teeth appear to be associated with significantly less EARR than are contralateral teeth with vital pulp. This study suggests that the possible complication of EARR in root-filled teeth may not be an important consideration in orthodontic treatment planning, and root canal treatment can be considered for stopping or decreasing EARR when severe EARR occurs during orthodontic treatment.


Assuntos
Polpa Dentária/fisiologia , Ortodontia Corretiva/efeitos adversos , Reabsorção da Raiz/etiologia , Ápice Dentário/patologia , Dente não Vital/fisiopatologia , Adolescente , Adulto , Fatores Etários , Feminino , Humanos , Incisivo/diagnóstico por imagem , Masculino , Dente Molar/diagnóstico por imagem , Doenças Periapicais/complicações , Radiografia Dentária Digital/métodos , Radiografia Panorâmica/métodos , Estudos Retrospectivos , Fatores de Risco , Reabsorção da Raiz/diagnóstico por imagem , Fatores Sexuais , Fatores de Tempo , Ápice Dentário/diagnóstico por imagem , Coroa do Dente/diagnóstico por imagem , Extração Dentária , Raiz Dentária/diagnóstico por imagem , Dente não Vital/diagnóstico por imagem , Adulto Jovem
18.
Clin Oral Investig ; 20(3): 433-41, 2016 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-26159778

RESUMO

OBJECTIVES: To evaluate the influence of restorative materials used on the rehabilitation of MOD cavities and loading type, on biomechanical behavior of wedge-shaped (WS) lesions in endodontically treated maxillary premolars. The investigation was conducted by 3D finite element analysis (FEA) and strain gauge test. MATERIALS AND METHODS: Six models were generated, with MOD cavities and endodontic treatment: A (MOD amalgam restoration), R (MOD composite restoration), AL (A + cervical lesion (L)), RL, ALR (A + cervical lesion restored with composite (LR)), and RLR. Each model underwent two compressive loading (100N): axial and oblique-45° angle to the long axis on the buccal cusp. The models were analyzed by von Mises criteria. For strain gauge test, 14 standardized maxillary premolars were treated according to the groups described for FEA. Two strain gauges were bonded on each sample submitted to compressive loading in a mechanical testing machine. RESULTS: A presented higher stress concentration and strain values than R. Oblique loading promoted highest stress concentration and strain rates for all groups. ALR and RLR presented similar stress-strain distribution pattern when compared to A and R. CONCLUSION: The interaction between MOD cavity restored with amalgam and oblique loading propitiated the highest stress concentration and strain values on cervical region and WS lesion. CLINICAL RELEVANCE: The MOD cavity restored with composite resin is a better option than amalgam to improve the biomechanical behavior of wedge-shaped lesion, avoiding dental failure. In addition, the occlusal interferences must be removed, allowing homogeneous contact distribution and preventing WS lesion progression.


Assuntos
Dente Pré-Molar/fisiopatologia , Resinas Compostas/química , Amálgama Dentário/química , Preparo da Cavidade Dentária/métodos , Materiais Dentários/química , Falha de Restauração Dentária , Restauração Dentária Permanente/métodos , Dente não Vital/fisiopatologia , Fenômenos Biomecânicos , Bis-Fenol A-Glicidil Metacrilato/química , Análise do Estresse Dentário , Módulo de Elasticidade , Análise de Elementos Finitos , Guta-Percha/química , Estresse Mecânico
19.
Rev. ADM ; 72(5): 272-274, sept.-oct. 2015.
Artigo em Espanhol | LILACS | ID: lil-775337

RESUMO

Durante muchos años se han utilizado los postes colados, considerados como un estándar en la odontología protésica, pero presentan limitantes técnicas y mecánicas, ya que exhiben altos módulos de elasticidad y, por lo mismo, imposibilitan la capacidad de disipar las fuerzas con efectividad, lo que significa concentrar tensiones dentro del conducto radicular. Literatura basada en evidencia científica describe a los postes de fibra de vidrio con módulos de elasticidad semejantes o próximos a la dentina, presentando propiedades anisotrópicas, en comparación con los postes tradicionales, que presentan propiedades isotrópicas. Se propone un concepto restaurador que involucra el poste, el cemento y la dentina, constituyendo un complejo homogéneo denominado ®monobloque¼ que permite un mejor comportamiento mecánico benéfico para el remanente dentario


For many years now, cast posts have been regarded as standard in prosthetics despite the technical and mechanical limitations caused by their high moduli of elasticity, which prevent the forces involved from being effectively dissipated and, therefore, concentrate stress within the root canal. Scientifi c evidence-based literature describes fi berglass posts with moduli of elasticity similar to or approaching that of dentin as having anisotropic properties, as opposed to the isotropic properties of traditional posts. We propose a restorative approach that involves the post, the cement, and the dentin, forming a homogeneous complex known as a ®monobloc¼ that enables enhanced mechanical behavior that benefits the remaining tooth structure.


Assuntos
Humanos , Fenômenos Biomecânicos , Dentina/fisiologia , Restauração Dentária Permanente/tendências , Técnica para Retentor Intrarradicular/tendências , Vidro/química , Cemento Dentário , Dente não Vital/fisiopatologia , Módulo de Elasticidade , Materiais Biocompatíveis/classificação , Resistência à Tração
20.
J Dent ; 43(9): 1106-1115, 2015 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-26149065

RESUMO

OBJECTIVES: To evaluate the fracture strength and the mode of failure of endodontically treated molars restored with CAD/CAM overlays with fiber reinforced composite build-up of the pulp chamber. METHODS: 40 Devitalized molars were cut over the CEJ and divided into five groups (n=8). The pulp chamber area was filled with: group 0 (control), no resin build-up; group 1, hybrid composite build-up (G-aenial posterior, GC); group 2, as in group 1 but covered with 3 nets of bi-directional E-glass fibers (EverStickNET, Stick Tech Ltd.); group 3, a FRC resin (EverX posterior, GC); group 4, as in group 3 but covered by the bi-directional fibers. The crowns were restored with CAD-CAM composite restorations (Lava Ultimate, 3M ESPE). Maximum fracture loads were recorded in Newton and data were analyzed using Kruskal-Wallis test (p<0.05). Fragments were analyzed using SEM. RESULTS: The mean static loads in Newton were: group 0: 2448 (546); group 1: 2817 (873); group 2: 2128 (952); group 3: 2429 (1091); group 4: 2577 (833). No significant differences were found between the groups (p>0.05). All specimens fractured in a catastrophic way, under the CEJ. The main crack evolved in the corono-apical direction. In groups 2 and 4 secondary fracture paths with apico-coronal direction were detected close to the bi-directional fibers' layer. CONCLUSIONS: For the restoration of endodontically treated molars, the incorporation of FRCs did not influence the load-bearing capacity of the tooth-restoration complex. The SEM analysis showed a low ability of the bi-directional fibers net in deviating the fracture but this effect was not sufficient to lead more favorable fracture patterns, over the CEJ. CLINICAL SIGNIFICANCE: The use of FRCs to reinforce the "core" of devitalized molars against vertical fractures under static loads seems useless when the thickness of the CAD/CAM composite overlay restoration is high.


Assuntos
Resinas Compostas , Falha de Restauração Dentária , Restauração Dentária Permanente/métodos , Dente Molar , Resinas Sintéticas , Dente não Vital , Humanos , Microscopia Eletrônica de Varredura , Dente Molar/lesões , Dente Molar/fisiopatologia , Dente Molar/ultraestrutura , Distribuição Aleatória , Fraturas dos Dentes/patologia , Fraturas dos Dentes/fisiopatologia , Dente não Vital/patologia , Dente não Vital/fisiopatologia , Suporte de Carga
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