Effect of endodontic sealer in young molars treated by undergraduate students - a randomized clinical trial

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.

Lateral luxation of incisor - a case report of using a new cone-beam computed tomography software and reposition guideline

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.

Biomechanical and morphological changes produced by ionizing radiation on bone tissue surrounding dental implant

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.

Effect of magnification during post space preparation on root cleanness and fiber post bond strength

Abstract 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.

Resumo Avaliar o efeito do método de visualização durante o preparo do espaço do pino sobre o remanescente de material obturador endodôntico e sobre a resistência adesiva do pino de fibra de vidro. Trinta incisivos centrais superiores humanos com canal radicular circular foram selecionados, foram desobstruídos a 15 mm e obturados. Os dentes foram divididos em 3 grupos (n=10), de acordo com o método de ampliação utilizado para inspeção do preparo: Controle, usando olho nu; lupa, usando uma lupa cirúrgica 3x cirúrgica; microscópio cirúrgico, usando um microscópio cirúrgico 6x. As raízes foram digitalizadas usando micro-CT antes e após a preparação do espaço para avaliação de resíduos remanescentes. Os pinos de fibra foram cimentados com cimento resinoso autoadesivo (RelyX U200, 3M-ESPE). Duas fatias de 1 mm de espessura dos terços cervical, médio e apical foram submetidas ao teste push-out (PBS). Os padrões de falhas foram classificados. Os dados de PBS foram analisados ​​usando análise de variância em dois fatores com medição repetida e o teste de Tukey. O nível de significância foi estabelecido em 5%. Resultados: O método de visualização não teve efeito no PBS (p=0,556). A região cervical apresentou valores maiores que a região apical, independentemente do método de inspeção (p=0,012). A falha adesiva entre o cimento resinoso e a dentina foi o modo de falha prevalente para todos os grupos. A análise de micro-CT não mostrou diferença na limpeza da raiz no canal radicular após a preparação do espaço do pino. Conclusão: O uso de dispositivos de ampliação como lupas e microscópios durante a realização de preparo não melhora o PBS e não afetou a permanência do material obturador remanescente de dentes anteriores.