Push-out bond strength of fiber posts to root dentin using glass ionomer and resin modified glass ionomer cements

OBJECTIVE: The purpose of this study was to assess the push-out bond strength of glass fiber posts to root dentin after cementation with glass ionomer (GICs) and resinmodified glass ionomer cements (RMGICs). MATERIAL AND METHODS: Fifty human maxillary canines were transversally sectioned at 15 mm from the apex. Canals were prepared with a step back technique until the application of a #55 K-file and filled. Post spaces were prepared and specimens were divided into five groups according to the cement used for post cementation: Luting & Lining Cement; Fuji II LC Improved; RelyX Luting; Ketac Cem; and Ionoseal. After cementation of the glass fiber posts, all roots were stored at 100% humidity until testing. For push-out test, 1-mm thick slices were produced. The push-out test was performed in a universal testing machine at a crosshead speed of 0.5 mm/minute and the values (MPa) were analyzed by Kolmogorov-Smirnov and Levene's tests and by two-way ANOVA and Tukey's post hoc test at a significance level of 5%. RESULTS: Fiber posts cemented using Luting & Lining Cement, Fuji II LC Improved, and Ketac Cem presented the highest bond strength to root dentin, followed by RelyX Luting. Ionoseal presented the lowest bond strength values (P>0.05). The post level did not influence the bond strength of fiber posts to root dentin (P=0.148). The major cause of failure was cohesive at the cement for all GICs and RMGICs. CONCLUSIONS: Except for Ionoseal, all cements provided satisfactory bond strength values. .

Enxerto ósseo onlay autógeno de área doadora intraoral: relato de caso / Autogenous onlay bone grafts from an intraoral donor site: case report

A reconstrução óssea com blocos de enxertos tem sido utilizada na Implantodontia com o propósito de possibilitar a instalação de implantes quando o tecido de suporte é insuficiente ou não possibilitaria o posicionamento do implante na sua forma ideal. A técnica de enxertia realizada com o uso de osso autógeno é considerada a primeira opção de tratamento por esse material possuir características mais próximas do ideal como osteogenicidade e biocompatibilidade. Áreas doadoras intrabucais demonstram fornecer tecido suficiente, com menor morbidade e custo comparadas as áreas extrabucais. O presente relato de caso, associado à revisão de literatura, tem como objetivo analisar e discutir os diferentes aspectos de um tratamento com utilização de enxerto autógeno como: definição dos parâmetros que levam a opção pelo tratamento com enxerto ósseo, limitações do tratamento, escolha da área doadora, descrição da técnica e escolha pela colocação dos implantes simultaneamente ou não ao enxerto

Reconstruction with bone block grafts has been used in Implantology in order to permit the installation of implants when the alveolar ridge support is insufficient or can’t provide the positioning of the implant in its ideal form. The grafting technique accomplished with the use of autogenous bone is considered the first choice of treatment because this material has characteristics closer to ideal such as osteogenic potential and biocompatibility. Intraoral donor sites have proved to provide enough quantity of bone, with lower morbidity and cost compared to extraoral areas. The present case report, associated with a literature review, aims to analyze and discuss the different aspects of treatment using autograft such as: defining the parameters that lead to choosing treatment with bone graft, limitations of treatment, choice of donor area, description of technique and choice for placing implants simultaneously or not to graft

Utilização de implante estreito de TiZr em região de alta incidência de carga: relato de caso / The use of TiZr narrow implant in high impact load region: case report

Implantes estreitos de titânio surgiram na Implantodontia com a indicação clássica de serem utilizados para substituição de incisivos laterais superiores, incisivos inferiores, espaços edêntulos pequenos e com baixa incidência de carga mastigatória. Porém, na literatura encontra-se relatos de falhas mecânicas e biológica desses implantes, quando utilizados em situações de maior incidência de carga mastigatória, como em caninos e molares. Para permitir uma ampliação das indicações dos implantes de diâmetro reduzido, uma nova liga foi desenvolvida com objetivo de compensar as deficiências relatada. Os novos implantes estreitos são confeccionados a partir de uma liga de titânio e zircônia (TiZr), com 13-17% de zircônia em sua composição e possuem 3,3 mm de diâmetro. A nova liga apresenta maior resistência do que os implantes de titânio grau IV e melhor biocompatibilidade que as ligas de Ti-6Al-4V. Assim, vem sendo uma alternativa viável para ampliar as indicações clássicas dos implantes estreitos convencionais. No caso apresentado, o implante estreito de TiZr foi utilizado em região de segundo molar inferior como pilar de uma prótese fixa de 4 elementos, a fim de permitir a reabilitação de uma paciente que possuía perda óssea vertical severa, necessitando o implante tangenciar do nervo alveolar inferior. O controle foi feito durante 15 meses sem apresentar qualquer complicação, sendo assim, concluiu-se que os implantes estreitos de TiZr podem ser utilizados em espaços edêntulos reduzidos e táboa óssea fina, independente do dente a ser substituído

Narrow titanium implants came with the classic indication for use for replacement of maxillary lateral incisors, lower incisors and small edentulous spaces with low incidence of masticatory load. However, the literature reports biological and mechanical failures of these implants when used in situations of higher incidence of masticatory load, such as canines and molars. To amplify the indication of small diameter implants, a new alloy was developed in order to compensate for the deficiencies reported. The new narrow implants are made from an alloy of titanium and zirconium (TiZr) with 13-17% of zirconia in their composition and have 3.3 mm diameter. The new alloy has higher resistance than the titanium implants grade IV and better biocompatibility than the alloy Ti-V-6Al4, therefore it has being a viable alternative to broaden the classical indications of narrow conventional implants. In the case reported, the Strait of TiZr implant was used in the region of the second molar as an abutment for a fixed prosthesis in the four elements in order to allow the rehabilitation of a patient with severe vertical bone loss requiring that the implant was tangent to lower alveolar nerve. The control was carried out for 15 months without any complications, and therefore, it was concluded that the narrow TiZr implants can be used in reduced edentulous spaces and thin bone, independent of the tooth to be replaced

Análise de resistência à tração de pinos de fibra de vidro cimentados com diferentes cimentos de ionômero de vidro através do teste pull-out / Evaluation of tensile strength of fiberglass posts cemented with different glass ionomer cements through pull-out-test

Para que se consiga resistência e retenção de pinos intrarradiculares é essencial a adequada seleção do agente cimentante. Objetivo: analisar diferentes tipos de cimento de ionômero de vidro utilizados na cimentação de pinos intrarradiculares de fibra de vidro, o método através do teste de resistência à tração pull-out. Métodos: Foram cimentados pinos de fibra de vidro em 50 caninos humanos, divididos nos seguintes grupos (n = 10): Grupo I ? Ionoseal (Voco), Grupo II ? Lining and Cement (GC), Grupo III ? Fuji II Improved (GC), Grupo IV ? Rely X Luting 2 (3M Espe), Grupo V ? Ketac Cem (3M Espe). Resultados: o teste Anova mostrou diferença significativa entre os grupos. O teste de Tukey mostrou que o Lining and Cement foi estatisticamente mais resistente que o Ionoseal (p < 0,05). Conclusão: assim, analisando-se os resultados, pode-se concluir que avaliando a resistência à tração dos pinos de fibra de vidro cimentados com diferentes cimentos de ionômero de vidro através do teste pull-out o cimento de ionômero de vidro convencional Lining and Cement se mostrou superior aos outros cimentos.

Effect of post length on endodontically treated teeth: analyses of tensile strength

Aim: This study compared the tensile strength of endodontically treated teeth restored withdifferent posts and cores with different post lengths. Methods: Sixty extracted intact canines wererandomly divided into 6 groups. Groups CP1, CP2 and CP3 were restored with custom cast postand-core and groups PF1, PF2 and PF3 were restored with prefabricated post and compositeresin core, with different combinations of post length of 5,0 mm, 7.5 mm and 10 mm, respectively(n = 10). All teeth were restored with a total metal crown. A tensile loading was applied at a 180-degree angle to the long axis until failure. Results: The 2-way analysis of variance (á=0.05)showed statistically significant difference (p<0.001) among the groups. However, when the meanfracture forces for the groups were compared (Groups 1, 2, 3, 4, 5 and 6: 134.5 N (34.2), 178.9N(40.1), 271,5 N (55.9), 161.7 N (22.0), 216.1 N (42.0) and 257.9 N (41.0), respectively), nosignificant differences could be detected among the groups restored with prefabricated post andcast post-and-core. It was found significant differences when it was compared the different lengthsfor each type of post (p<.05). Conclusions: This study showed that increasing post lengthsignificantly increased the tensile strength of prefabricated posts and cast post-and-core used inendodontically treated teeth. On the other hand, significant differences were not found whencomparing endodontically treated teeth restored with custom cast post-and-cores or pre-fabricatedposts and composite resin cores with the same post length.

Avaliação da resistência ao cisalhamento por extrusão (push-out) de pinos de fibra de vidro cimentados com diferentes cimentos resinosos em um ambiente úmido: Estudo Piloto / Evaluation of shear bond strength (push-out) of glass fiber posts cemented with different resin cements in humid ambient. Pilot study

Objetivo: O objetivo deste trabalho foi analisar a resistência ao cisalhamento por extrusão de diferentes cimentos empregados na cimentação de pinos de fibra de vidro em ambiente úmido. Material e métodos: Para tanto, 21 caninos humanos tiveram suas coroas removidas, de modo que se obtiveram 15 mm de remanescente radicular. Depois de tratados endodonticamente, os dentes foram preparados para receber pinos de fibra de vidro. Os dentes selecionados foram divididos aleatoriamente em sete grupos: Grupo I - RelyX ARC, Grupo II - Enforce, Grupo III - BISCEM, Grupo IV - DUO-LINK, Grupo V - Cemente Post, Grupo VI - Variolink II e Grupo VII - RelyX U100. Cada dente foi seccionado perpendicularmente ao longo do eixo do pino com disco diamantado de alta concentração, obtendo-se uma fatia de cada profundidade com espessura de, aproximadamente, 1 mm, retiradas a partir de 1 mm, 5 mm e 9 mm do limite cervical de cada raiz, totalizando-se 63 espécimes. A análise microscópica foi realizada nesses três níveis: superficial, médio e profundo. Após análise, os espécimes foram avaliados pelo teste de push-out. Resultados: O teste Anova a dois critérios mostrou diferenças estatisticamente significativas entre os terços, cimentos e interação entre eles (p < 0,05). O teste de Tukey mostrou que os cimentos resinosos autoadesivos (Biscem e U100) e o terço cervical radicular apresentaram resultados significativamente superiores no teste de push-out (p < 0,05). As fotomicrografias mostraram que houve fendas maiores nas regiões médias e apicais do que nas regiões cervicais. Conclusão: Os resultados deste estudo mostraram que os cimentos autoadesivos apresentaram resultados superiores quando comparados aos cimentos adesivos. A região radicular cervical apresentou os melhores resultados no teste de cisalhamento.

A multidisciplinary approach for the management of hypodontia: case report

Hypodontia is the congenital absence of one or more teeth and may affect permanent teeth. Several options are indicated to treat hypodontia, including the maintenance of primary teeth or space redistribution for restorative treatment with partial adhesive bridges, tooth transplantation, and implants. However, a multidisciplinary approach is the most important requirement for the ideal treatment of hypodontia. This paper describes a multidisciplinary treatment plan for congenitally missing permanent mandibular second premolars involving orthodontics, implantology and prosthodontic specialties.

Efeito de diferentes elastômeros na adaptação cervical de coroas totais metálicas / Effect of different elastomers on cervical fit of full metal crowns

Objective: The aim of this study was to evaluate the cervical fit of full metal crowns using four different elastomers. Methods: A stainless steel metallic die similar to a prepared first upper molar was obtained. Four di-fferent elastomeric impression materials were utilized: polysulfide (A), polyether (B), condensation silicone (C) and addition silicone (D). Forty molds were created, 10 for each group. It was obtained 40 gypsum abutments. After the end of this stage, it was performed complete metal crowns on all specimens. Crown displacement was measured through a comparative microscope, obtaining diametrically opposite points. Results: The re-sults were the following: Group D (31.97 um), Group B (49.57 um), Group A (51.12 um), Group C (61.12 um). The analysis of variance (ANOVA) test and a Tukey test for multiple comparisons were used to analyze the results. Conclusions: There were significant differences among all groups, except for Groups A and B. The major result of displacement was Group C. The best results were shown by Group D (p < 0.05).

Effect of post length on endodontically treated teeth: fracture resistance

Aim: This study compared the fracture resistance of endodontically treated teeth restored with posts and cores systems with different post lengths. Methods: Sixty extracted intact canines were randomly divided in 6 groups of 10 teeth each, as follows: groups 1, 2 and 3 were restored with custom cast post-and-core, and groups 4, 5 and 6 were restored with prefabricated post and composite resin core, with different post lengths (5.0, 7.5 and 10 mm, respectively). A compressive load was applied at a 45-degree angle to the long axis until failure occurred. Results: Two-way analysis of variance (á=0.05) showed statistically significant difference between the groups(p<0.001). However, when the mean fracture forces for the groups were compared (group 1:254.4 N; groups 2, 3, 4, 5, 6 – 331.7 N, 434.7 N, 405.4 N, 395.6 N and 393.8 N, respectively),no significant differences could be detected among the three groups restored with prefabricated post and group 3. Conclusions: This study showed that an increased post length in teeth restored with prefabricated posts does not significantly increase the fracture resistance of endodontically treated teeth. On the other hand, endodontically treated teeth restored with custom cast-post and core showed significant increase on fracture resistance when the post length is increased.

Linear dimensional changes in plaster die models using different elastomeric materials

Dental impression is an important step in the preparation of prostheses since it provides the reproduction of anatomic and surface details of teeth and adjacent structures. The objective of this study was to evaluate the linear dimensional alterations in gypsum dies obtained with different elastomeric materials, using a resin coping impression technique with individual shells. A master cast made of stainless steel with fixed prosthesis characteristics with two prepared abutment teeth was used to obtain the impressions. References points (A, B, C, D, E and F) were recorded on the occlusal and buccal surfaces of abutments to register the distances. The impressions were obtained using the following materials: polyether, mercaptan-polysulfide, addition silicone, and condensation silicone. The transfer impressions were made with custom trays and an irreversible hydrocolloid material and were poured with type IV gypsum. The distances between identified points in gypsum dies were measured using an optical microscope and the results were statistically analyzed by ANOVA (p < 0.05) and Tukey's test. The mean of the distances were registered as follows: addition silicone (AB = 13.6 µm, CD=15.0 µm, EF = 14.6 µm, GH=15.2 µm), mercaptan-polysulfide (AB = 36.0 µm, CD = 36.0 µm, EF = 39.6 µm, GH = 40.6 µm), polyether (AB = 35.2 µm, CD = 35.6 µm, EF = 39.4 µm, GH = 41.4 µm) and condensation silicone (AB = 69.2 µm, CD = 71.0 µm, EF = 80.6 µm, GH = 81.2 µm). All of the measurements found in gypsum dies were compared to those of a master cast. The results demonstrated that the addition silicone provides the best stability of the compounds tested, followed by polyether, polysulfide and condensation silicone. No statistical differences were obtained between polyether and mercaptan-polysulfide materials.

Sistemas cerâmicos atuais: revisão de literatura / Current ceramic systems: literature review

A fabricação de restaurações em cerâmica está se tornando cada vez mais popular, devido ao crescente avanço na qualidade desse material e na tecnologia empregada na confecção dessas restaurações. Essa evolução ocorreu graças, principalmente, à tecnologia CAD/CAM, que possibilitou o uso de cerâmicas de alta resistência na fabricação de próteses sem metal, com qualidade e uniformidade, padronizando os processos e reduzindo custos. O objetivo deste trabalho é realizar uma revisão da literatura dos sistemas cerâmicos existentes, bem como descrever os aspectos relacionados à estética, propriedades mecânicas, adaptação marginal, caracteristicas dos pônticos e conectores, e modo de cimentação, procurando mostrar as vantagens, desvantagens, indicações e contra-indicações da cada sistema.

Resolução estética com laminado cerâmico unitário: relato de caso / Aesthetics resolution with single ceramic veneer: a case report

A Odontologia Restauradora atual funde conceitos estéticos e conservadores. Assim, são preconizados tratamentos que apresentam bom prognóstico em longo prazo, preservação de estrutura dentária e alta satisfação estética do paciente. Inseridos nesse contexto, destacam-se os laminados cerâmicos. O objetivo deste trabalho é descrever, por meio de um relato de caso, os desafios do planejamento e da execução de um laminado cerâmico na reconstrução de um incisivo central esteticamente comprometido.

Avaliação da retenção de coroas totais metálicas cimentadas com diferentes cimentos provisórios / Evaluation of total metallic crowns retention cemented with different provisional cements

O objetivo deste trabalho foi avaliar a resistência à tração de coroas totais metálicas cimentadas com diferentes cimentos temporários. Para tanto, foram selecionados trinta molares superiores humanos, os quais foram preparados para receber coroas totais metálicase divididos aleatoriamente em três grupos de dez cada. As coroas do Grupo 1 foram cimentadas com hidróxidode cálcio (Dycal®); as do Grupo 2 (Temp-Bond®) e 3 (pasta Lysanda®), com cimento e pasta de óxido de zinco e eugenol, respectivamente. Decorridas 24h, submeteram-se os corpos-de prova à tração em máquina de ensaios universal. Terminados os testes, todas as coroas e dentes foram limpados e fez-se a recimentação, submetendo os espécimes novamente ao teste de tração após 21 dias. Os resultados foram avaliados por meio de análise de variância a um critério e a comparação entre as médias foi realizada pelo método de comparação de Student-Newman-Keuls. A análise estatística mostrou diferença significativa entre os grupos submetidos ao tracionamento um dia e 21 dias após a cimentação. A resistência à tração após um dia foi maior para o Grupo 1 (21,92 Kgf), seguido, respectivamente, pelos grupos 2 (12,95 Kgf) e 3 (3,64 Kgf). Após 21 dias, os resultados encontrados para o Grupo 1 (1,52 Kgf) e 2 (1,40 Kgf) foram inferiores aos anteriores, ao passo que o Grupo 3 (3,76 Kgf) se manteve semelhante, não havendo diferenças significativas entre si. Observando os resultados, pode-se concluir que o fator tempo pode ser determinante na diminuição da resistência à tração de diferentes cimentos temporários

Influence of intraradicular post and crown ferrule on the fracture strength of endodontically treated teeth

The aim of this study was to investigate the fracture strength of endodontically treated teeth restored with different posts and variable ferrule heights. Sixty freshly extracted human canines were treated endodontically and randomly assigned to 6 groups (n=10), being restored with custom-made cast post-and-core (CP0 and CP3 groups), prefabricated post and composite resin core (PF0 and PF3 groups), and composite resin (CR0 and CR3 groups). The CP0, PF0 and CR0 groups presented no ferrule and the CP3, PF3 and CR3 presented 3 mm of coronal structure. All teeth were restored with full metal crowns. The fracture strength was measured in a universal testing machine at 45o to the long axis of the tooth until failure. Data were analyzed statistically by 2-way ANOVA and Tukey's test (?=0.05). When the mean fracture strength values were compared (CP0 group - 820.20 N, CP3 group - 1179.12 N; PF0 group - 561.05 N; PF3 group - 906.79 N; CR0 group - 297.84 N; and CR3 group - 1135.15 N) there was statistically significant among the groups (p<0.05), except for the three groups with 3 mm of coronal remaining, which were similar to each other. The results of this study showed that the ferrule in crowns promoted significantly higher fracture strength in the endodontically treated teeth.

O objetivo neste estudo foi avaliar a resistência à fratura de dentes tratados endodonticamente restaurados com diferentes pinos e diferentes alturas de remanescente dentinário da coroa. Sessenta caninos recém-extraídos foram tratados endodonticamente, separados em 6 grupos (n=10) e restaurados com núcleo metálico fundido (CP0 e CP3), pino pré-fabricado e núcleo em resina composta (PF0 e PF3) ou resina composta (CR0 e CR3). Os grupos CP0, PF0 e CR0 não possuíam férula e os grupos CP3, PF3 e CR3 apresentaram 3 mm de remanescente coronário. Todos os dentes foram restaurados com coroas totais metálicas. A resistência à fratura foi medida em máquina universal de ensaios com o longo eixo do dente posicionado a 45 graus em relação ao carregamento axial, até que ocorresse fratura. A análise de variância 2 critérios (?=0,05) mostrou diferença estatisticamente significativa entre os grupos. Quando as médias das forças para fratura foram comparadas (CP0 = 820,0 N; CP3= 1179,12 N; PF0 = 561,05 N; PF3 = 906,79 N; CR0 = 297,84 N; e CR3 = 1135,15 N) não foram observadas diferenças significativas entre os 3 grupos com 3 mm de remanescente coronal. Os resultados mostraram que a presença de férula em coroas aumenta significantemente a resistência à fratura de dentes tratados endodonticamente.

Correlation between margin fit and microleakage in complete crowns cemented with three luting agents

Microleakage can be related to margin misfit. Also, traditional microleakage techniques are time-consuming. This study evaluated the existence of correlation between in vitro margin fit and a new microleakage technique for complete crowns cemented with 3 different luting agents. Thirty human premolars were prepared for full-coverage crowns with a convergence angle of 6 degrees, chamfer margin of 1.2 mm circumferentially, and occlusal reduction of 1.5 mm. Ni-Cr cast crowns were cemented with either zinc phosphate (ZP) (S.S. White), resin-modified glass-ionomer (RMGI) (Rely X Luting Cement) or a resin-based luting agent (RC) (Enforce). Margin fit (seating discrepancy and margin gap) was evaluated according to criteria in the literature under microscope with 0.001 mm accuracy. After thermal cycling, crowns were longitudinally sectioned and microleakage scores at tooth-cement interface were obtained and recorded at ×100 magnification. Margin fit parameters were compared with the one-way ANOVA test and microleakage scores with Kruskal-Wallis and Dunn's tests (alpha=0.05). Correlation between margin fit and microleakage was analyzed with the Spearman's test (alpha=0.05). Seating discrepancy and marginal gap values ranged from 81.82 µm to 137.22 µm (p=0.117), and from 75.42 µm to 78.49 µm (p=0.940), respectively. Marginal microleakage scores were ZP=3.02, RMGI=0.35 and RC=0.12 (p<0.001), with no differences between RMGI and RC scores. The correlation coefficient values ranged from -0.27 to 0.30 (p>0.05). Conclusion: Margin fit parameters and microleakage showed no strong correlations; cast crowns cemented with RMGI and RC had lower microleakage scores than ZP cement.

Fracture resistance of weakened roots restored with composite resin and glass fiber post

This study evaluated the fracture resistance of weakened roots restored with glass fiber posts, composite resin cores and complete metal crowns. Thirty maxillary canines were randomly divided into 3 groups of 10 teeth each: teeth without weakened roots (control); teeth with partially weakened roots (PWR) and teeth with and largely weakened roots (LWR). The control group was restored with glass fiber posts and a composite resin core. Teeth in the PWR and LWR groups were flared internally to standardized dimensions in order to simulate root weakness. Thereafter, the roots were partially filled with composite resin and restored in the same way as in the control group. The specimens were exposed to 250,000 cycles in a controlled chewing simulator. All intact specimens were subjected to a static load (N) in a universal testing machine at 45 degrees to the long axis of the tooth until failure. Data were analyzed by one-way ANOVA and Dunnett's test for multiple comparisons (p=0.05). There were statistically significant difference differences (p<0.01) among the groups (control group = 566.73 N; PWR = 409.64 N; and LWR = 410.91 N), with significantly higher fracture strength for the control group. There was no statistically significant difference (p>0.05) between the weakened groups. The results of this study showed that thicker root dentin walls significantly increase the fracture resistance of endodontically treated teeth.

Este estudo avaliou a resistência à fratura de raízes fragilizadas restauradas com pinos de fibra de vidro, núcleos de resina composta e coroas totais metálicas. Trinta caninos superiores foram aleatoriamente divididos em 3 grupos. Dentes sem enfraquecimento (grupo controle); grupo de raízes parcialmente enfraquecidas e amplamente enfraquecidas. O grupo controle foi restaurado com pinos de fibra de vidro e núcleo em resina composta. Os dentes dos grupos de raízes parcialmente e amplamente enfraquecidas foram internamente preparadas de maneira padronizada simulando enfraquecimento. Após isto, as raízes foram parcialmente preenchidas com resina composta e restauradas como no grupo controle. Os espécimes foram expostos a 250.000 ciclos em uma máquina de ciclagem mecânica. Todos os dentes intactos foram submetidos à carga estática (N) em uma máquina de ensaio universal a 45 graus ao longo eixo do dente até a sua falha. Os resultados foram analisados através do teste ANOVA a 1 critério e teste de Dunnett para comparações múltiplas (p=0,05). A análise estatística revelou diferenças significantes (p<0,01) entre os três grupos (grupo controle = 566,73 N; RPE = 409,64 N; e ERA = 410,91 N). Quando as três médias de resistência a fratura são ranqueadas as duas menores não se diferem. Os resultados deste estudo mostraram que uma maior espessura de paredes dentinárias aumenta significantemente a resistência à fratura de dentes tratados endodonticamente.

Surgical crown lengthening: a 12-month study - radiographic results

OBJECTIVE: The purpose of this study was to perform a radiographic follow-up evaluation after a 12-month healing period, following crown lengthening surgery. MATERIAL AND METHODS: Twenty-three periodontally healthy subjects (mean age 32.5 years) that required crown lengthening surgery in premolars were recruited. In a total of 30 premolars, full thickness flaps, osseous resection, and flap suturing were performed. The restorative margin was defined in the pre-surgical phase and maintained unaltered during the healing period, serving as a reference point. Standardized bitewing radiographs were taken before and after osseous reduction, and at 2, 3, 6, and 12-month healing periods. RESULTS: Intact lamina dura was observed at both mesial and distal alveolar crests only from the 3rd month. At 12-months, all alveolar crests presented lamina dura. The overall mean distance from the restorative margin to the alveolar crest achieved after osseous resection was 3.28±0.87 mm at mesial and 2.81±0.51 mm at distal sites. No significant radiographic changes in the bone crest were observed during a 12-month healing period. CONCLUSION: The findings of this study suggest that the radiographic proximal bone level observed on bitewing radiographs following crown lengthening surgery can be used as a reference to predict the future level of the healed alveolar crest.