Effects of the resin base and retention depth on fracture resistance of molars restored with nano-ceramic endocrowns / 北京大学学报(医学版)

OBJECTIVE@#To compare the effects of resin base and different retention depth on the fracture resistance of mandibular molars restored with nano-ceramic endocrowns.@*METHODS@#Forty mandibular molars selected and randomly divided into 5 groups: ① The control group which was consisted of intact teeth, ② the non-resin base group, ③ the 2 mm retention depth group, ④ the 3 mm retention depth group, ⑤ the 4 mm retention depth group, respectively. After tooth preparation, in vitro root canal therapy was conducted, which was followed by endocrown design, production and adhesive of groups ②-⑤. All the samples were under load (N) of the universal mechanical testing machine after embedding. The fracture pattern of each sample was observed under stereomicroscope. Then the microstructure of the fracture surface was observed by scanning electron microscopy.@*RESULTS@#The fracture loads of each group were respectively: the control group fracture load was (3 069.34±939.50) N; experimental groups: fracture load of (2 438.04±774.40) N for the group without resin base; fracture load of (3 537.18±763.65) N for the group with 2 mm retention depth. The fracture load of the retention depth 3 mm group was (2 331.55±766.39) N; the fracture load of the retention depth 4 mm group was (2 786.98±709.24) N. There was statistical significance in the effect of resin base and different retention depth on the fracture loads of molars restored with nano-ceramic endocrown (P < 0.05). Repairable fractures in each group were as follows: control group 2/8, non-resin base group 1/8, retention depth of 2 mm group 1/8, retention depth of 3 mm group 2/8, and retention depth of 4 mm group 0/8. The effects of the retention depth and the presence of resin base on the fracture resistance of the resin nano-ceramic endocrowns were statistically significant (P < 0.05). Scanning electron microscopy showed more arrest lines and small twist hackles on the fracture surface of the restorations with resin base (retention depths of 2 mm, 3 mm, and 4 mm), with cracks extending towards the root. In addition to the characteristics above, more transverse cracks parallel to the occlusal surface, pointing outwards from the center of the pulp cavity retention, were also observed on the fracture surface of the non-resin base restorations.@*CONCLUSION@#When molar teeth with nano-ceramic endocrowns are restored, resin base and the retention depth of 2 mm help the teeth to obtain optimal fracture strength.

Fracture Resistance of Anterior CAD/CAM Nanoceramic Resin Endocrowns with Different Preparation Designs / Resistência à Fratura de Endocrowns de Resina Nanocerâmica CAD / CAM Anterior Com Diferentes Projetos de Preparação

Objective: The aim of the study was to evaluate the effect of extension of endocrown in pulp space and the effect of ferrule on the fracture resistance of anterior endocrowns made of nano-ceramic resin blocks. Material and Methods: Twenty-eight freshly extracted human upper central incisor teeth were prepared to receive CAD/CAM nanoceramic resin endocrowns with four different designs. The specimens were divided into two groups (n = 14) according to the extension of the endocrown inside root canal (A:short and B:long), then each group was further subdivided into another two subgroups (n = 7) according to the presence or absence of ferrule effect (1:ferrule and 2: no ferrule). Endocrowns were then fabricated using CEREC in lab and nanoceramic resin blocks (DENTSPLY Sirona, Germany) and LAVA ultimate (3M ESPE, Germany) blocks size 14L. Results: Two-way ANOVA showed that the ferrule (p > 0.0001) had statistically significant effect on the fracture resistance. However, the extension of the endocrown into the canal had no statistical significant effect on the fracture resistance (p = 0.837). The interactions between the independent variables (extension into the canal and ferrule) had statistically significant effect on the fracture resistance (p = 0.029). Load to fracture for group 1A was 439.53 N, 1B was 306.46 N, 2A was 516.29 N and 2B was 242.04 N. Conclusions: Fracture resistance was not improved by the long or short extensions of the endocrowns in the pulp space, however, the ferrule effect shows significant improvement of the fracture resistance of the nanoceramic resin endocrowns. (AU)

Objetivo: O objetivo deste estudo foi avaliar o efeito da extensão da coroa endocrown na câmara pulpar e o efeito férula na resistência à fratura de coroas endocrowns anteriores confeccionadas através de blocos de resina nanocerâmica. Material e Métodos: Vinte e oito dentes incisivos centrais superiores humanos recém-extraídos foram preparados para receber endocrowns de resina nanocerâmica CAD / CAM com quatro diferentes tipos de preparos. Os espécimes foram divididos em dois grupos (n = 14) de acordo com a extensão da endocrown dentro do canal radicular (A: curto e B: longo), então cada grupo foi subdividido em outros dois subgrupos (n = 7) de acordo com presença ou ausência do efeito férula (1: com férula e 2: sem férula). As endocrowns foram usinadas através do CEREC In Lab e blocos de resina nanocerâmica (DENTSPLY Sirona, Alemanha) e blocos de LAVA ultimate (3M ESPE, Alemanha) tamanho 14L. Resultados: ANOVA dois fatores demostrou que a férula (P> 0,0001) teve efeito estatisticamente significativo na resistência à fratura. No entanto, a extensão do endocrown no canal não teve efeito estatisticamente significativo na resistência à fratura (P = 0,837). As interações entre as variáveis independentes (extensão no canal e férula) tiveram efeito estatisticamente significativo na resistência à fratura (P = 0,029). A carga para fratura do grupo 1A foi de 439,53 N, 1B foi de 306,46 N, 2A foi de 516,29 N e 2B foi de 242,04 N. Conclusões: A resistência à fratura não foi melhorada pelas extensões longas ou curtas das endocrowns na câmara pulpar, no entanto, o efeito férula mostrou uma melhora significativa na resistência à fratura das coroas endocrowns de resina nanocerâmica (AU)

Indications and Success Rate of Endo Crowns - A Systematic Review

Endodontically treated teeth are most commonly restored using post-retained foundation restoration and a crown which has certain well-established drawbacks. Nowadays, the emergence of minimal invasive dentistry has led to increased use of endocrowns for restoring such teeth. However, their indications and success rates have not been explored widely enough to merit their full implementation in dental practice. This systematic review attempts to achieve this purpose by accumulating evidence from current literature that underscores endocrowns’ indications and success rates. METHODSThe electronic search strategy was performed in three databases (PubMed, Google Scholar, and EBSCO) using MeSH terms endocrowns, or endocrown success rates of endocrowns or endo crowns in dentistry or endodontically treated teeth or ceramic or monoblock or CAD-CAM, confined to articles published between 1st January 2015 and 20th November of 2019. All selected articles were evaluated to determine as to whether or not they could be included in the SR. Abstracts and titles were screened independently by 2 investigators and duplicates if any were removed. For possible inclusion after reading abstract, full-text assessment of the article was performed based on eligibility criteria. Manual extraction of data from the retrieved publications was done. RESULTSA total of 20 articles was found on related topic from electronic and manual searching, out of which, 2 were duplicates and hence removed. Further 7 articles were removed in screening and again 2 were removed after reading full-text, thus making the final count of 9 articles for the systematic review. Among the nine articles, 3 were clinical studies, 1 was a retrospective patient series study, while remaining were in-vitro studies. Out of 9, 7 articles (77 %) reported endocrowns to be successful and 2 articles (22 %) gave contrary outcomes. CONCLUSIONS Most of the articles included in this SR agree that endocrowns are a desirable restorative tool in dentistry. Other systematic reviews and meta-analyses with a significant number of included publications and studies should be conducted to expand the generalizability potential of such results

Influence of CAD/CAM Material and Preparation Design on the Long-term Fracture Resistance of Endocrowns Restoring Maxillary Premolars / Influência do material de CAD / CAM e tipo de preparo na resistência à fratura a longo prazo de coroas endodônticas adesivas na restauração de pré-molares superiores

Objective: To evaluate the effect of different occlusal preparation designs and CAD/CAM materials on the fracture resistance of maxillary premolars end crowns. Materials and Methods: sixty-four endodontically treated upper first premolars were randomly divided into four groups according to ceramic materials (Vita Enamic and IPS emax CAD) and occlusal preparation designs (Anatomical and horizontal butt joint). After teeth preparation, the restorations were all made by CAD/CAM system (Cerec MCXL). Half of each group had undergone cyclic fatigue testing of 105 cycles with 50N loading force at a frequency of 0.5Hz in a mechatronic chewing simulator machine, and then all samples were loaded to fracture using a universal testing machine with a cross head speed of 0.5 mm/min recording the fracture resistance values in N . The specimens were measured and statistically analyzed using using three-way analyses of variance (ANOVA), followed by serial two-way and one-way ANOVAs at each level of the study. P-values were adjusted for multiple comparisons using BENFORRONI correction and the significance level was set at P ≤ 0.05 for all tests. Results: Vita Enamic endocrowns showed higher fracture resistance values than IPS e max specimens. Conclusions: Vita Enamic endocrowns with anatomical preparations were found to be more favourable restoring endodontically treated maxillary premolars (AU)

Objetivo: Avaliar o efeito de diferentes tipos de preparo oclusal e materiais CAD/CAM na resistência à fratura de coroas endodônticas adesivas em pré-molares. Materiais e Métodos: Sessenta e quatro primeiros pré-molares superiores tratados endodonticamente foram divididos randomicamente em quatro grupos de acordo com os materiais cerâmicos (Vita Enamic e IPS emax CAD) e tipos de preparo oclusal (Recobrimento Incisal Anatômico e Horizontal). Após o preparo dental, as restaurações foram confeccionadas pelo sistema CAD/CAM (Cerec MCXL). Metade de cada grupo foi submetido a testes de fadiga cíclica de 105 ciclos com força de carga de 50N a uma frequência de 0,5Hz em uma máquina simuladora de mastigação mecatrônica, e então todas as amostras foram submetidas a fratura por uma máquina de teste universal com uma velocidade de 0,5 mm / min registrando os valores de resistência à fratura em N. As amostras foram medidas e analisadas estatisticamente usando análises de variância de três fatores (ANOVA), seguidas por ANOVAs de dois fatores e de um fator em cada nível do estudo. Os valores de p foram ajustados para comparações múltiplas usando a correção BENFORRONI e o nível de significância estabelecido foi de P ≤ 0,05 para todos os testes. Resultados: Coroas endodônticas adesivas da Vita Enamic mostraram maiores valores de resistência à fratura do que as amostras de IPS emax. Conclusões: Verificou-se que as coroas endodônticas adesivas da Vita Enamic com preparos com recobrimento incisal anatômico foram mais favoráveis para restaurar os pré-molares superiores tratados endodonticamente (AU)

Fracture load of nano-ceramic composite material for anterior endocrown restorations / Carga de fratura de material compósito nano-cerâmico para restaurações endocrown anteriores

Objective: to evaluate ability of Nano Ceramic Composite endocrown to withstand occlusal forces when used in the anterior region. Material and Methods: eighty endodontically treated maxillary central incisors teeth were randomly divided into two main groups according to the restoration type. Forty of these teeth were post, core and crown restorations and 40 were endocrown restorations. Then they were divided by halves into two subgroups according to the material used 20 were made with Lava Ultimate and the other 20 with IPS e.max. Each subgroup was then further subdivided into two divisions according to the remaining tooth structure above the CEJ (n = 10): 2 mm and 0.5 mm above the CEJ. After teeth preparation, the restorations were all made by CAD/CAM system (Cerec MCXL). All samples had undergone cyclic fatigue testing, and then loaded to fracture using a universal testing machine. The specimens were measured and statistically analyzed using Mann-Whitney test for comparing the mean changes between the groups. Results: Lava Ultimate showed higher mean fracture load values than IPS e.max specimens. Conclusions: endocrowns were found to be more favorable when used on endodontically treated teeth than the conventional post, core and crown restorations.(AU)

Objetivo: Avaliar a capacidade do compósito nanocerâmico endocrown para suportar forças oclusais quando usado na região anterior. Material e Métodos: Oitenta incisivos centrais superiores tratados endodonticamente foram divididos aleatoriamente em dois grupos principais, de acordo com o tipo de restauração. Quarenta desses dentes receberam restaurações com retentor intrarradicular, núcleo e coroa e 40 receberam restaurações endocrown. Em seguida, foram divididos pela metade em dois subgrupos, de acordo com o material utilizado, sendo 20 confeccionados com Lava Ultimate e os demais 20 com IPS e.max. Cada subgrupo foi posteriormente subdividido em dois, de acordo com a estrutura dentária remanescente acima da JEC (n = 10): 2 mm e 0,5 mm acima do JEC. Após o preparo dos dentes, todas as restaurações foram realizadas pelo sistema CAD/ CAM (Cerec MCXL). Todas as amostras foram submetidas a testes de fadiga cíclica e submetidas ao esforço até a fratura em uma máquina universal de testes. As amostras foram medidas e analisadas estatisticamente pelo teste de MannWhitney para comparação das alterações médias entre os grupos. Resultados: lava Ultimate apresentaram valores médios mais altos de carga até a fratura do que as amostras IPS e.max. Conclusões: as endocrowns mostraram-se mais favoráveis quando utilizadas em dentes tratados endodonticamente do que as restaurações convencionais com retentor intrarradicular, núcleo e coroa.(AU)

Assessment of clinical effect of IPS e. max press ceramic endocrowns in preserving endodontically treated molars / 中华医学美学美容杂志

Objective To evaluate the clinical effect of IPSe. max press ceramic endocrowns being used in preserving endodontically treated molars. Methods Forty-five endodontically treated molars were selected from 45 patients in this study. All the molars had been endodontically treated and performed with ultrasonic scaling. After 1-2 weeks, the crowns and pulp chambers were prepared. The impressions and master casts were gained and IPSe. max press ceramic endocrowns were fabricated in the lab. The endocrowns were cemented with resin cement. The further consultations were offered to these molars after 6 months and 1 year. The difference of sulcus bleeding index among these endodontically treated molars and the same teeth in the opposite sides was compared. Results In these cases, 100 % of endocrowns were