RESUMEN

The aim of the study was to collect data about the prevalence and risk factors of apical periodontitis in a population of endodontically treated patients. The study group included 151 patients (52 males, 99 females; mean age 48.36 ± 15.708 yrs.) with 391 endodontically treated teeth (mean follow-up of 5.25 ± 1.759 yrs.). According to the initial tooth diagnosis, root-filled teeth were divided into Group A, root-filled teeth treated for pulpitis or for the purpose of prosthetic pulpectomies (vital pulp group), and Group B, root-filled teeth with non-vital pulp (necrotic pulp). Clinical and radiographic evaluation of the root and its periapical area were performed to establish the success/failure of endodontic therapy, the quality of the root canal fillings (length, density, taper), and coronal restoration. The presence of recurrent caries, periodontal pathology, or endo-periodontal lesions were also recorded. Univariate and multivariate analyses were used to determine the risk factors for apical periodontitis and calculate their odds ratios (ORs). For the root-filled vital pulp tooth group, the highest risks for apical periodontitis are associated with inadequate homogeneity (OR 30.938), periodontitis (OR 9.226), and over-filling (OR 8.800). For the root-filled non-vital pulp tooth group, the highest risks are associated with periodontitis (OR 4.235) and age over 60 yrs. (OR 4.875). For the necrotic pulp tooth group, multivariate analysis identified an age > 60 yrs., filled molars, intracanal posts, poor coronal restoration quality, under-filling, and periodontitis as significant combined risk factors. Inadequate root canal filling and periodontitis in both groups were risk factors associated with most cases of apical periodontitis. Other risk factors include age > 60 yrs., poor coronal restoration quality, and the presence of intracanal posts in root-filled teeth with necrotic pulp.

RESUMEN

Restoring extensively damaged endodontically treated teeth presents a challenging task due to the state of biomechanical deterioration affecting long-term prognosis. Therefore, the study aims to assess and compare the biomechanical performance of endocrowns and post core-crown restorations in anterior endodontically treated teeth with severe coronal structure loss. Following PRISMA guidelines, a systematic search was conducted using PubMed, Scopus, Web of Science, and Google Scholar for articles published from January 2014 to March 2024. Two independent reviewers screened and selected studies based on the predefined inclusion and exclusion criteria. The included studies were analyzed using the QUIN tool for risk of bias assessment in in-vitro studies. Additionally, the biomechanical outcomes were collected for qualitative comparative analysis. Twelve studies were included in this systematic review. In most studies, Endocrowns demonstrated comparable fatigue resistance under load to failure to post core-crown restorations. Endocrowns without ferrule exhibited a higher rate of debonding but had significantly more repairable failures. Conversely, post core-crown restorations demonstrated higher fracture resistance with the presence of ferrule, but were associated with more catastrophic failure patterns. Additionally, endocrowns generated lower stress levels in both the restorative material and the luting material compared to post core-crown restorations. Among the tested materials, lithium disilicate ceramics provided the best biomechanical properties. Overall, the studies included provided sufficient information for most evaluation criteria of the QUIN risk of bias assessment tool. Endocrowns are a viable and conservative approach for restoring endodontically treated anterior teeth, offering comparable biomechanical performance to traditional post core-crown restorations and less catastrophic failures. The findings of this systematic review suggest that endocrown restorations, especially with lithium disilicate ceramics and proper ferrule design, can improve fracture resistance and longevity of rehabilitated teeth, enhancing patient outcomes for severely damaged anterior endodontically treated teeth.

RESUMEN

AIM: To investigate what happens to cross-sectionally identified root-filled teeth over a 6-year period, regardless of the time that elapsed since primary root canal treatment, in a cohort of adult patients regularly attending a Public Dental Service. A secondary aim was to investigate how the cumulative events affecting root-filled teeth over the same time were associated with variables obtained from a baseline examination. METHODOLOGY: Adult patients with ≥1 previously root-filled tooth and regularly attending the Public Dental Service in Örebro County were enrolled for study participation in 2015. General dental practitioners examined all identified root-filled teeth in this cohort at baseline using a standardized protocol and were also responsible for further decision-making and treatments. After six years, information on events of the root-filled teeth was collected from dental records. The highest rating (most invasive treatment) on a 5-point ordinal scale was used in the analyses. Regression analyses with stepwise selection were performed for associations between patient- and tooth-related factors and events. RESULTS: A total of 445 patients with 1007 root-filled teeth were followed the entire observation time. Twenty (2.0%) of the root-filled teeth had endodontic retreatment and 150 (14.9%) were extracted over six years. Among teeth with periapical radiolucency or pain, the majority did not undergo retreatment or extraction; however, the multivariate analysis demonstrated that retreatment or extraction was associated with baseline recordings of teeth with periapical radiolucency (p < .0001), tenderness to percussion (p < .0001), and poor coronal restoration (p < .0001). CONCLUSIONS: This study corroborates the notion that in general dentistry, root-filled teeth with radiological signs of apical disease often remain untreated over time. Furthermore, it also reveals that root-filled teeth presenting with mild pain do not necessarily receive any intervention. However, teeth with baseline signs of apical periodontitis, pain, or inadequate coronal restoration were more likely to have received intervention during the six-year period.

Asunto(s)

RESUMEN

Purpose: This study investigated the fracture resistance and failure modes of custom-fabricated post- and core dental restorations using various CAD/CAM materials. Materials and Methods: Seventy-five mandibular second premolars were allocated to five groups (n = 15) and prepared for standardized post and core restorations. The groups included a control group comprising cast metal and four CAD/CAM materials: Vita Enamic, Shofu HC, Trilor, and PEKK. Fracture resistance was assessed using a compressive force at a crosshead speed of 1 mm/min until failure occurred. Data were analyzed using one-way analysis of variance (ANOVA) and chi-square tests. Results: The metal group had the highest fracture resistance (244.41 ± 75.20 N), with a significant variance compared to that in the CAD/CAM groups (p < 0.001). No significant differences were observed among the non-metallic groups. Conclusions: While several CAD/CAM materials displayed satisfactory flexural properties, cast metal posts showed superior fracture resistance in endodontically treated teeth but were mostly associated with catastrophic failure. The clinical application of CAD/CAM materials for post-core restorations presents a viable alternative to traditional metal posts, potentially reducing the risk of unfavorable fractures.

RESUMEN

PURPOSE: Non-vital teeth usually exhibit substantial loss of coronal and radicular tooth structure, and use of posts after root canal treatment is controversial. This review examined whether placement of posts influences clinical behavior and survival probability of endodontically treated teeth (ETT). METHODS: An electronic search, without time restrictions, for publications written in English was undertaken in PubMed, Scopus, and Web of Science. Terms related to four main components (endodontically treated teeth, fixed prosthesis, post restoration, and survival rate) were used for the database search strategies. RESULTS: 57 studies met the inclusion criteria and were included in the qualitative analysis. Of the publications chosen for qualitative analysis, 17 clinical studies (11 prospective and 6 retrospective studies) were found to be suitable for quantitative analysis. These studies included 7,278 patients (7,330 ETT), with a mean age ± standard deviation (SD) of 45.46 ± 12.1 years. There was a statistically significant difference in survival rate between ETT with or without posts (P < 0.001). CONCLUSION: As compared with teeth with no posts, post placement on ETT may improve clinical performance and survival probability of endodontically treated teeth.

RESUMEN

TRIAL DESIGN: This is a randomized, controlled, superiority, double-blinded, parallel-group, two-arms trial with an allocation ratio of 1:1. This study aimed to assess whether the cavity design could affect the clinical performance of the CAD/CAM generated indirect resin composite restoration in endodontically treated teeth (ETT) evaluated using the Modified USPHS criteria after a two-year follow up. METHODS: A total of 30 participants who underwent endodontic treatment for MOD cavities in permanent molars were divided randomly into two parallel groups (n = 30 restorations) according to the performed cavity design to group 1 in which there was no cuspal reduction (inlay) and group 2 in which cuspal reduction was performed (overlay). All pulp chambers were filled with bulk fill flowable composite, and the cavities were prepared following the criteria of the cavities for indirect restorations and restored using nano-hybrid composite resin blocks (Brilliant, Coltene, Switzerland). The restorations were evaluated using the modified USPHS criteria at baseline, six months, one-year and two years follow-up visits. For qualitative data, frequencies (n) and percentages (%) were used to display the data, while mean and standard deviation (SD) were used for quantitative data. The normality of the data was evaluated using the Shapiro-Wilk and Kolmogorov-Smirnov tests. For every test, P ≤ 0.05 was used as the significance threshold. RESULTS: Twenty-six individuals completed the follow-up period after receiving the assigned intervention.The inter-group comparison showed that, at the 6- months and 12- months observation points, the overlay design had significantly better marginal adaptation, less incidence of discoloration or tooth/restoration fracture, and similar marginal integrity and caries incidence to the inlay design. After 24- months, the overlay design still had better marginal adaptation, less incidence of discoloration or tooth/restoration fracture and less caries incidence in comparison to the inlay design, while there was no difference in the marginal integrity between either design. CONCLUSIONS AND CLINICAL RELEVANCE: Cuspal reduction in endodontically treated teeth showed better clinical performance than the cusp preservation thus, the former is more reliable.

Asunto(s)

RESUMEN

The restoration of endodontically treated teeth (ETT) remains a significant challenge in modern dentistry. These teeth often suffer from substantial structural damage due to both the original pathology and the invasive nature of endodontic procedures. Consequently, ETT are more susceptible to fractures compared to vital teeth, necessitating restorative strategies that can effectively restore both function and aesthetics while minimizing the risk of failure. In recent years, advances in adhesive dentistry and the development of high-strength ceramics have further expanded the restorative options for ETT. Bonded restorations have gained popularity as they preserve more tooth structure and enhance the overall strenght of the tooth-restoration complex. The choice of restorative material and technique is influenced by numerous factors, including the amount of remaining tooth structure, the functional requirements of the tooth, and the aesthetic demands of the patient. Despite the plethora of available materials and techniques, the optimal approach to restoring ETT remains a topic of ongoing research and debate. In this comprehensive review, the current state of and recent advances in restoring damaged endodontically treated teeth are explored. Numerous therapeutic options exist, involving a wide range of materials. This article aims to present the biomaterial advancements of the past decade and their applications, offering alternative approaches to treating damaged ETT with the goal of prolonging their retention on the dental arch and serving as a valuable resource for dental practitioners who face this issue daily.

RESUMEN

Background/purpose: Recently, an effective core build-up system for teeth with flared root canals is needed. This research aimed to evaluate the effect of foundation restorations using a composite resin core with a fiber post reinforced with a zirconia tube for the surface strain at the cervical area and the fracture load of teeth with flared root canals. Materials and methods: Bovine teeth were shaped to mimic human premolars with flared root canals and restored using three types of composite resin foundation restorations with each materials described below: a fiber post (FC), a zirconia tube (ZC), a fiber post and zirconia tube (ZFC). Each specimen was restored with a zirconia crown. The surface strains of the specimens at the cervical area and fracture loads were analyzed using a one-way analysis of variance (ANOVA), followed by Tukey's honest significant difference test. Results: The surface strains of Groups ZFC and ZC were significantly lower than that of Group FC in the buccal root. The fracture strengths of Groups ZFC and ZC were significantly higher than that of Group FC. The strength of Group ZFC was significantly higher than that of Group ZC. Conclusion: The use of a composite resin core with a zirconia tube for the simulated premolar with flared root canals reduced surface strain at the cervical area and provided higher fracture strength compared to using a composite resin core with a fiber post. And the zirconia tubes provided even higher fracture strength when used with a fiber post.

RESUMEN

A high prevalence of post-treatment apical periodontitis associated to variables such as endodontic treatment quality and missed canals has been reported. AIM: The aim of this study was to evalúate the quality of endodontic treatment and the frequency of missed canals associated with teeth with apicalperiodontitis (AP) through CBCTin a Colombian sub-population. MATERIAL AND METHOD: This was a cross-sectional study assessing 318 cone beam computed tomography (CBCT) scans of endodontically treated teeth from Colombian individuals. The scans were taken using J Morita X550 (J Morita Corporation, Osaka, Japan), with voxel size 0.125 to 0.20 mm. All endodontically treated teeth were assessed for quality of treatment, presence of missed canals and AP. Allsamples were analyzed bytwo endodontics specialists and an radiology specialist. Chi-square or Fisher 's test and odds ratio were calculated to identify the association and risk relationship between the presence of AP and the study variables. RESULTS: Missed canals were found in 18.61% (86/462), and 95.3% were associated with AP. The frequency of AP was 62.34% (288/462) for all the evaluated teeth. AP was found in 27.43 % (79/288) of the teeth with adequate endodontic treatment, in contrast to 72.57% (209/288) of the teeth with inadequate treatment (P<0.01). The frequency of missed canals was highest in maxillary molars, with 55.23% (58/105), with 96.55% presenting AP. The second mesiobuccal canal wasthe most frequently missed canal, 88.52%o(54/61), with AP in 90.74% (49/54) of the cases. CONCLUSIÓN: There was a high frequency of teeth with missed canals and PA. More than half of the teeth with missed canals were maxillary molars, with MB2 being the most common canal, commonly presenting apical periodontitis.

Uma alta prevalência de periodontite apical pós-tratamento associada a variáveis como qualidade do tratamento endodôntico e fracasso do tratamento é relatada na literatura. O objetivo deste estudo foi avaliar a qualidade do tratamento endodôntico e a frequência e fracasso do tratamento associados a dentes com periodontite apical (PA) por meio de tomografia computadorizada de feixe cônico (TCFC) em uma subpopulação colombiana. MATERIAL E MÉTODO: Este foi um estudo transversal que avaliou 318 tomografias computadorizadas de dentes tratados endodonticamente de indivíduos colombianos. Os exames foram realizados utilizando o tomógrafo J Morita X550, com tamanho de voxel de 0,125 a 0,20 mm. Todos os dentes tratados endodonticamente foram avaliados quanto à qualidade do tratamento, presença de canais não localizados e AP. Todas as amostras foram avaliadas por dois especialistas em endodontia e um especialista em radiologia. Foram calculados o teste qui-quadrado ou de Fisher e a razão de chances para identificar associação e relação de risco entre a presença de PA e as variáveis do estudo. RESULTADOS: Foram encontrados canais não localizados em 18,61% (86/462) e 95,3% estavam associados à PA. A frequência de AP foi de 62,34% (288/462) para todos os dentes avaliados. AP foi encontrada em 27,43% (79/288) dos dentes com tratamento endodôntico adequado, em contraste com 72,57% (209/288) dos dentes com tratamento inadequado (P<0,01). A frequência de canais não localizados foi maior nos molares superiores, com 55,23% (58/105), sendo que 96,55% apresentavam PA. O canal mésio-palatino (MB2) apresentou maior frequência de canal não localizado (88,52% - 54/61), com PA em 90,74% (49/54) dos casos. CONCLUSÃO: Houve alta frequência de dentes com canais não localizados e com PA. Mais da metade dos dentes com canais não localizados eram molares superiores, sendo o MB2 é o canal com a maior frequência, comumente apresentando periodontite apical.

Asunto(s)

RESUMEN

OBJECTIVES: The purpose of the present study was the radiographic evaluation of endodontically treated teeth presenting periapical radiolucency and unintentional overfilling with gutta-percha or sealer on treatment outcome and persistence of the extruded materials. METHOD AND MATERIALS: After assessment using periapical index (PAI), 202 roots filled with gutta-percha and zinc oxide-eugenol sealer (Roth 811, Roth International), exhibiting unintentional overfilling and periapical radiolucency were selected. All cases had at least 1 year of follow-up. Type of extruded material, periapical status, and removal/persistence of the extruded material were evaluated by two independent observers. Data were statistically analyzed using logistic and linear regression analysis. RESULTS: Tooth location (P .001), follow-up period (P .001), and type of extruded material (P = .004) significantly influenced treatment outcomes. Specifically, posterior roots exhibited better outcomes compared to anterior, and cases with overfilling of sealer showed superior healing potential compared to those with gutta-percha overfilling. Additionally, longer recall periods were associated with improved treatment success. The type of extruded material (P .001) and follow-up period (P .001) significantly affected the presence of extruded material in the follow-up radiograph. The persistence of extruded material was greater when gutta-percha was extruded, and extruded materials were less detected when the follow-up period was longer. CONCLUSION: Teeth with periapical radiolucency and unintentional overfilling require longer follow-up intervals for effective monitoring of healing. Treatment outcome was associated with the type of extruded materials used in the present study. The persistence of those materials in the periapex did not affect healing.

Asunto(s)

RESUMEN

Background: Dentists utilize various techniques and materials for post and core restoration of endodontically treated teeth, which remains a noteworthy health concern and can be addressed through interdisciplinary strategies to enhance outcomes. Therefore, this study aimed to evaluate the technical quality of the residual gutta-percha (GP) and posts by analysing the periapical radiographs of endodontically restored teeth. Methods: A total of 594 periapical digital radiographs were evaluated for tooth type, post material, post shape, design, diameter, length, residual GP, GP length, GP tapering, GP homogeneity, and final restoration. Frequency distribution and cross-tabulation of the variables were performed. Results: Maxillary molars had the highest frequency of restorations, including posts, accounting for 27.4 %, followed by maxillary premolars (25.4 %) and maxillary anterior teeth (19.2 %). The prefabricated metallic posts were most commonly used (81.0 %), among these, 50.4 % were screwed posts. Tapered posts were the most commonly used (65.6 %). The percentage of posts with an acceptable length was 58.2 %. The most commonly used posts exhibited a width of one-third of the root diameter, accounting for 87.0 %. Suitable GP lengths were observed in 61.1 % of the restorations, and 62.8 % demonstrated adequate GP homogeneity. The findings of this study revealed that crown restoration accounted for 42.6 % of the studied sample. Conclusions: The technical quality of the remaining GP after restoration was comparable to that of previous epidemiological investigations. However, the technical quality of the post was deemed suboptimal.

RESUMEN

The outcome of an endodontic procedure determines the clinical success of the treated tooth. A post-endodontic restoration will restore the tooth's form, function, and aesthetics while preserving and safeguarding its existing tooth structure. To restore endodontically treated teeth with the best possible tissue preservation, the least invasive preparation is the aim. Full-coverage crowns are still more popular than partial-coverage crowns. Conservative dental procedures such as inlays, overlays, and endocrowns maximize the amount of tooth structure that is intact while minimizing the amount of tooth structure that is removed. Compared to posts, cores, and crowns, endocrowns offer several advantages in terms of ease of preparation, application, and reduced clinical visits and time. Endocrown is a simple, minimally invasive preparation usually given when margins are supragingival, which makes it self-cleansable and maintains natural tooth contact, preventing interference with periodontal tissue. This case report focuses on managing endodontically treated teeth with the fabrication of endocrown using computer-aided design (CAD) and computer-assisted manufacturing (CAM) techniques.

RESUMEN

PURPOSE: To evaluate the fracture resistance of zirconia overlays, considering various preparation designs and the presence of endodontic access. MATERIALS AND METHODS: Ninety translucent zirconia (5Y-PSZ) overlay restorations were divided into six groups (n = 15/group) based on different preparation designs, with and without endodontic access: chamfer margin 4 mm above the gingival level without (group 1) and with endodontic access (group 2); margin 2 mm above the gingival level without (group 3) and with endodontic access (group 4); overlay with no chamfer margin without (group 5) and with endodontic access (group 6). Restorations were bonded to mandibular first molar resin dies, and the groups with endodontic access were sealed with flowable resin composite. All restorations underwent 100,000 cycles of thermal cycling between 5°C and 55°C, followed by loading until fracture. Maximum load and fracture resistance were recorded. ANOVA with Tukey post-hoc tests were used for statistical comparison (α < 0.05). RESULTS: Fracture resistance significantly varied among overlay designs with and without endodontic access (p < 0.001), except for the no-margin overlays (groups 5 and 6). Overlays with a 2 mm margin above the gingival margin with endodontic access (group 4) exhibited significantly higher fracture resistance compared to both the 4-mm supragingival (group 2) and no-margin (group 6) designs, even when compared to their respective intact groups (groups 1 and 5). There were no significant differences between the no-margin and 4-mm supragingival overlays. CONCLUSION: The more extensive zirconia overlay for mandibular molars is the first choice since the 2 mm margin above the gingival level design withstood considerable loads even after undergoing endodontic access. A no-margin overlay is preferred over the 4-mm supragingival design as it preserves more tooth structure and there was no outcome difference, irrespective of endodontic access. Caution is warranted in interpreting these findings due to the in vitro nature of the study.

RESUMEN

PURPOSE: The study aims to investigate the influence of the ferrule effect and types of posts on the stress distribution in three morphological types of the maxillary central incisor. MATERIALS AND METHODS: Nine models were created for 3 maxillary central incisor morphology types: "Fat" type - crown 12.5 mm, root 13 mm, and buccolingual cervical diameter 7.5 mm, "Medium" type - crown 11 mm, root 14 mm, and buccolingual cervical diameter 6.5 mm, and "Slim" type - crown 9.5 mm, root 15 mm, and buccolingual cervical diameter 5.5 mm. Each model received an anatomical castable post-and-core or glass-fiber post with resin composite core and three ferrule heights (nonexistent, 1 mm, and 2 mm). Then, a load of 14 N was applied at the cingulum with a 45° slope to the long axis of the tooth. The Maximum Principal Stress and the Minimum Principal Stress were calculated in the root dentin, crown, and core. RESULTS: Higher tensile and compression stress values were observed in root dentin using the metallic post compared to the fiber post, being higher in the slim type maxillary central incisor than in the medium and fat types. Concerning the three anatomical types of maxillary central incisors, the slim type without ferrule height in mm presented the highest tensile stress in the dentin, for both types of metal and fiber posts. CONCLUSION: Post system and tooth morphology were able to modify the biomechanical response of restored endodontically-treated incisors, showing the importance of personalized dental treatment for each case.

RESUMEN

Background: The aim was to quantify the time elapsed between tooth reconstruction and the end of endodontic treatment, and to assess differences according to sex, age, and tooth group. Material and Methods: A retrospective study was conducted with patient clinical records. Data relating to patient characteristics, treated teeth, endodontic treatment, and subsequent restorative treatment were recorded. Results: For this study, 355 endodontically treated teeth by undergraduate students during 2019 were included. 24 teeth (6.76 %) were not restored, more direct (86.4 %) than indirect (13.6 %) restorations were performed, and the most frequent type of restoration was complex filling. The mean elapsed time from endodontic completion to direct restoration was 7 days, with a minimum of 0 and a maximum of 90 days. For indirect restorations the mean elapsed time was 21 days. Conclusions: The median elapsed time for endodontic tooth reconstruction was 7 days (IQR = 7), however, treatment should not be considered completed until the tooth has been properly restored. In cases where an indirect restoration was also necessary, the median elapsed time was higher (21 days; IQR = 31.5).

RESUMEN

OBJECTIVE: The purpose of this systematic review was to assess the impact of the incomplete ferrule on the fracture of endodontically treated teeth (ETT). DATA: The keywords such as "incomplete ferrule," "ferrule," "ferrule effect," "residual dentin," "remaining dentin," or "remaining coronal dentin" were used for searching, and only in vitro studies investigating the incomplete ferrule effect on natural teeth were included. SOURCES: PubMed, Medline, Embase, Cochrane Library, and Science Direct databases, and manual-searching. STUDY SELECTION: The search strategy yielded 1633 hits, and a total of 19 in vitro studies closely related to the effect of incomplete ferrule on ETT were included. CONCLUSION: The presence of an incomplete ferrule may significantly increase the fracture resistance of restored ETT, compared with restored ETT without ferrule. The number of residual axial walls of the incomplete ferrule may have an impact on the fracture resistance and fracture mode. The location of residual axial walls of the incomplete ferrule may affect the fracture resistance but not the fracture mode. CLINICAL IMPLICATIONS: Limited data suggest that the presence of incomplete ferrule has a positive effect on the fracture resistance of restored ETT. An incomplete ferrule can be an alternative for restoring ETT when a complete ferrule is not present. Nevertheless, further high-quality studies are still needed to offer more robust evidence and to take potential confounding factors into account.

Asunto(s)

RESUMEN

Purpose: The aim of this work is to conduct a literature review to highlight all the parameters involved in sub-prosthetic radicular fractures of teeth supported by metallic dental core. Materials and Methods: The following research was performed among published studies over the last 10 years in two PubMed/Medline and Scopus and supplemented by manual searching within the bibliographies. The search was restricted to publications in English and French. Results: Out of the 1464 articles initially identified, 18 studies met our inclusion criteria and were subsequently included in the literature review. These consisted of eight Finite Element Analysis Studies, two Retrospective Studies and one Randomized Controlled Trial. The results of this review show that radicular fractures are influenced by several variables, including predisposition, with maxillary premolars and mandibular molars being the most commonly affected teeth. Intracanal preparation can induce crack formation, leading to localized high stress concentrations. Increased ferrule height to 2 mm significantly enhances dental fracture resistance. Using high modulus of elasticity alloys results in nearly complete stress transmission to dentin due to their limited deformability and absorption capacity. The highest fracture resistance is achieved when posts are sealed using resin-modified glass-ionomer cement. Longer posts may be preferable to prevent vertical fractures. Additionally, occlusal factors, through repetitive stresses, contribute to crack propagation from surface defects, a phenomenon termed fatigue fracture. Conclusion: These findings have significant implications. Practitioners should be aware of the predisposition of certain teeth, the importance of preserving the ferrule effect, the choice of root post materials, post Cement Material and the role of occlusal forces in managing and preventing vertical root fractures.

RESUMEN

PURPOSE: This research aimed to investigate fracture resistance of endodontically treated maxillary premolars restored using preheated thermo-viscous and fiber-reinforced bulk fill resin composite, in vitro. METHODOLOGY: Sixty sound human maxillary premolars were selected and divided randomly into 6 groups of ten teeth each (n = 10). Group 1; is the positive control with sound unprepared teeth (P), Group 2; is the negative control in which Mesio-occluso-distal (MOD) cavities were left unrestored (N), Group 3; includes the teeth restored by incremental packing with conventional nanohybrid composite (ChP), Group 4; includes teeth restored with short fiber reinforced bulk fill composite (EF), Group 5; includes teeth restored with preheated thermo-viscous bulk fill composite (VB), and Group 6; includes teeth restored using packable bulk fill composite (XF) Tested restorative materials were bonded with a universal adhesive in self-etch mode. Teeth were kept in distilled water for 24 h at 37 °C proceeded by thermocycling (5- 55 °C, 1200×). Teeth were then exposed to compressive load till fracture at a crosshead speed of 1 mm/min. One-way ANOVA followed by Tukey post-hoc test was implemented to compare between more than two groups in non-related samples. The significance level was established at α = 0.05 for both tests. RESULTS: Intact teeth significantly recorded the highest fracture resistance values among all groups. A significant difference was recorded among all the tested groups, with the EF recording the highest values, followed by the VB group then the XF group and ChP that recorded the lowest data. Negative control premolars significantly recorded the lowest fracture. CONCLUSIONS: After thermocycling, endodontically treated maxillary premolars restored with pre-heated thermos-viscous composite did not exhibit an increase in fracture resistance. Notably, our findings indicate that short fiber-reinforced composite demonstrated significantly higher fracture resistance compared to other types of composites assessed in this study. This suggests the potential superiority of short fiber-reinforced composite in enhancing the overall structural integrity of endodontically treated teeth subjected to occlusal forces.

Asunto(s)

RESUMEN

OBJECTIVE: This study was conducted to assess the influence of combining different forms of fiber-reinforced composites (FRC) on the mechanical behavior and bond strength of compromised endodontically treated teeth (ETT). MATERIALS AND METHODS: Eighty extracted human premolar teeth were randomly divided into five experimental groups according to the type of intra-radicular restoration and the canal preparation design which was either non-flared (Group 1), flared (Groups 2-5), closed-apex (Groups 1,3,5) or open-apex (Groups 2,4). Standard prefabricated fiber posts were used as intra-radicular restoration for Groups 1-3 while Groups 4-5 were restored with anatomically customized relined fiber posts. After composite core fabrication, all samples were sent for an artificial aging process. Fracture resistance and push-out bond strength tests were then carried out through a universal testing machine followed by mode of failure analysis via a stereomicroscope and scanning electron microscope. RESULTS: Pairwise Log-Rank comparisons revealed that the survival rate of Group 2 and Group 3 was significantly lower than all other groups after artificial aging. The highest fracture resistance value (1796 N) was recorded in Group 5 and was significantly higher than that of the other groups (p < 0.05), while Group 2 exhibited the lowest fracture resistance (758 N), which was significantly lower compared to the other groups. Group 5 and Group 4 demonstrated a significantly higher push-out bond strength, at all root thirds, than Group 3, Group 2, and Group 1 (p < 0.05). The most frequently observed failure mode in the tested groups occurred between the resin cement and radicular dentin. CONCLUSION: The use of short fiber-reinforced composite (SFRC) to reline the prefabricated FRC post has been proven to have superior fracture resistance with favorable failure patterns and increased push-out bond strength values compared to standard prefabricated FRC posts.

Asunto(s)