Exploring fiberglass post numbers for enhanced fatigue resistance in molars without coronary remnants.

This study aimed to assess the fatigue resistance of molars lacking a coronary remnant, using zero, one, two, or three fiberglass posts. Forty caries/crack-free human molars with coronal portions removed at the pulp chamber floor were randomly allocated into four groups (n=10). Following endodontic treatment, posts (Whitepost DC/DC.E 0.5, 1.0, FGM) were silanized (silane agent, Angelus) and cemented with a resin cement (RelyX U200, 3M ESPE). Resin composite cores (Z350, 3M ESPE) were built, and metal crowns were fabricated and cemented using the same luting system. Samples underwent cyclic fatigue testing at 45°, applying load in the occlusal surface at 10 Hz and 100 N initial load for 10,000 cycles, with 50 N increments every 10,000 cycles until failure. Fatigue failure load and cycles for failure data were recorded and subjected to survival analysis through Kaplan-Meier and Mantel-Cox post hoc tests, and Weibull analysis. Fractography patterns of failed crowns were qualitatively analyzed. The group without posts exhibited the lowest fatigue performance (p < 0.05) for both fatigue failure load and cycles to failure. Superior fatigue performance was observed in the three-post group, followed by groups with one or two posts, corroborated by the Weibull characteristic strength parameter. Weibull moduli were similar among conditions. All specimens exhibited failure involving detachment of the restorative set (posts/core/crown) with a portion of the dental remnant, without tooth fracture. Thus, when restoring mandibular molars without crown remnants, the use of fiberglass posts promotes greater fatigue resistance to oblique loads.

Assessing transparency practices in dental randomized controlled trials.

BACKGROUND: To evaluate transparency practices in randomized controlled trials (RCTs) in dentistry. METHODS: This meta-research study included RCTs in dentistry regardless of topic, methods, or level of detail reported. Only studies in English were considered. We searched PubMed for RCTs in dentistry published in English from December 31, 2016, to December 31, 2021. The screening was performed in duplicate, and data extracted included journal and author details, dental specialty, protocol registration, data and code sharing, conflict of interest declaration, and funding information. A descriptive analysis of the data was performed. We generated maps illustrating the reporting of transparency items by country of the corresponding author and a heat table reflecting reporting levels by dental specialty. RESULTS: A total of 844 RCTs were included. Only 12.86% of studies reported any information about data and code sharing. Protocol registration was reported for 50.36% of RCTs. Conflict of interest (83.41%) and funding (71.68%) declarations were present in most studies. Conflicts of interest and funding were consistently reported regardless of country or specialty, while data and code sharing had a low level of reporting across specialties, as well as low dissemination across the world. Protocol registration exhibited considerable variability. CONCLUSIONS: Considering the importance of RCTs for evidence-based dentistry, it is crucial that everyone who participates in the scientific production and dissemination process actively and consistently promotes adherence to transparent scientific standards, particularly registration of protocols, and sharing of data and code.

Endorsement of open science practices by dental journals: A meta-research study.

OBJECTIVES: This study evaluates the endorsement of open science practices by dental journals. MATERIALS AND METHODS: This was a meta-research study that included journals listed in the 2021 Journal Citation Reports under Dentistry. A comprehensive evaluation was performed by accessing journal websites to ascertain the availability of publicly accessible instructions to authors in Portuguese, English, or Spanish. A researcher extracted information from the "Instructions for Authors" section, encompassing the journal's impact factor, mention of any reporting guidelines, details on data sharing, acceptance of articles in preprint format, and information regarding study protocol registration. Descriptive data analysis was conducted using the Stata 14.0 program, and an Open Science Score (OSS) (ranging from 0 to 100 %) was calculated for each journal by considering five open science practices. Pearson's correlation test was conducted to determine the relationship between the OSS score and journal impact factor. RESULTS: Ninety journals were included in the study. Most journals (70 %) indicated the mandatory use of reporting guidelines, while 60 % recommended data sharing. Conversely, 46.7 % did not provide information on study protocol registration, and 44.4 % stipulated them as mandatory for authors. Regarding preprints, 50 % of the journals did not provide any information, but 46.7 % confirmed their acceptance. The mean OSS was 52.9 % (standard deviation 26.2). There was a weak correlation (Pearson's correlation coefficient of 0.221) between the journal impact factor and OSS (P-value=0.036). CONCLUSION: This study found varying degrees of endorsement of open science practices among dental journals. CLINICAL SIGNIFICANCE: Dental practitioners rely on high-quality, evidence-based research for informed decision-making. By assessing the endorsement of open science practices, our study contributes to improving the quality and reliability of dental research, ultimately enhancing the evidence base for clinical practice.

Metaresearch study highlights the gender gap in randomized controlled trials in dentistry.

BACKGROUND AND OBJECTIVES: This study aimed to assess the gender gap in randomized controlled trials (RCTs) in dentistry in terms of authorship, collaborations, metrics, funding and reporting of good research practice and transparecy. METHODS: The search was performed in PubMed for RCTs restricted to English texts in the dental field, indexed from 12/31/2016 to 12/31/2021. Two reviewers screened the studies in line with the eligibility criteria. A total of 844 articles were included. The name and gender of authors, citation metrics, funding, reporting of characteristics of good research practice and transparency were extracted. We considered "collaboration between authors" when the corresponding author was different from the first author. RESULTS: The proportion of women as first authors was 46.56% and 40.12% for corresponding authors. The analysis showed that when a woman is the corresponding author, the probability of the first author also being a woman is 57% higher compared to the first author being a man. For "protocol registration" and "data sharing," the prevalence of reporting was higher when women were first authors. CONCLUSION: A gender gap in dentistry RCTs was identified and related to the participation of women as first and corresponding authors and the collaboration between authors.

Reporting quality of scoping reviews in dental public health.

BACKGROUND: The study aimed to explore reporting characteristics of scoping reviews in dental public health and the impact of some factors on the reporting quality. METHODS: This study searched for dental public health scoping reviews in PubMed and Scopus without year restrictions and restricted to English-language publications. Study selection was undertaken by two reviewers independently. One reviewer, after training, extracted data from included studies considering general study characteristics and reporting characteristics. The impact of PRISMA-ScR publication, journal endorsement, and use of study protocol on the reporting was explored. RESULTS: Eighty-one scoping reviews were included. Five items presented rates of appropriate reporting higher than 80% considering the overall percentage. Related to the impact of PRISMA-ScR publication, six items were found more often in scoping reviews published after the publication of PRISMA-ScR than in scoping reviews published before the publication of PRISMA-ScR. With regards to journals endorsement, only two reporting characteristics were found more often in scoping reviews published in journals that endorse the PRISMA-ScR statement than in scoping reviews published in non-endorsers journals. Last, regarding the use of the pre-specified protocol, five reporting characteristics presented differences in studies reporting the use of pre-specified protocol than in studies that did not mention the use of a protocol. All differences were statistically significant. CONCLUSIONS: Important information is missing in the included scoping reviews demonstrating crucial reporting problems.

Factors associated with decision-making for replacing the temporary coronal restoration after endodontic treatment

Aim: This study aimed to evaluate the decision-making by patients to replace temporary restorations with permanent restorations after endodontic treatment and to verify the associated factors and evaluate the quality/integrity of the temporary restorative material within one month. Methods: This is a cross-sectional study using non-probabilistic sampling which analyzed patients after one month of endodontic treatment. The self-administered questionnaire contained sociodemographic, treatment decision-making and endodontic treatment questions. The restoration present in the mouth was evaluated in the clinical oral examination. The Poisson Regression test was used to verify the prevalence ratio. Results: The prevalence failure to perform permanent restorations was 61.1% of patients, and 42.7% reported not having adhered. The reasons are lack of time and not knowing the importance of replacing the restoration with a definitive one. The glass ionomer temporary restorative frequency was higher among those who chose not to replace the temporary restoration with a permanent one (PR=5.19; 95%CI 2.10-12.33). In addition, there was an association between the quality of the restorative material and the type of material, and the best clinical quality of the restoration was statistically associated with glass ionomer and composite resin. Conclusions: The findings show the importance of guidance by the dental surgeon in helping patients decide to replace their temporary restoration

Reporting characteristics of systematic review abstracts published in the proceedings of the SBPqO meeting

Aim: This study aimed to assess the reporting characteristics of systematic review abstracts published in the proceedings of the Sociedade Brasileira de Pesquisa Odontológica (SBPqO) meeting. Methods: We selected abstracts published in the SBPqO meeting proceedings of 2019 and 2020, mentioning that a systematic review was conducted in the title, objective or methods sections. One researcher performed the screening and the data extraction after a pilot test training. The following data were extracted: affiliation of the primary author, dental specialization, the term "systematic review" mentioned in the title, reporting of the objective, reporting of eligibility criteria, reporting of information sources, reporting of the number of included studies and if a meta-analysis was performed. A descriptive analysis of the data was performed with data summarized as frequencies. Results: We included 235 abstracts. A total of 20 studies were from the Universidade de Uberlândia (8.5%), and the main specialization was Restorative and Esthetic Dentistry, with 47 studies (20%). Most of the studies mentioned the term "systematic review" in the title (n=219; 93.2%) and reported the objective (n=231; 98.3%). A great majority of studies did not report the eligibility criteria (n=97; 41.3%) or it was classified as unclear (n=96; 40.8%). The great majority of studies only reported the databases searched (n=103; 43.8%) or databases and date of search (n=74; 31.5%). Most of the studies reported the number of included studies (n=204; 86.8%). Conclusion: Based on this study, the reporting characteristics of systematic review abstracts published in the proceedings of the SBPqO meeting are satisfactory. However, there is room for improvement

Factors influencing the clinical performance of the restoration of endodontically treated teeth: An assessment of systematic reviews of clinical studies.

STATEMENT OF PROBLEM: How best to restore endodontically treated teeth is still unclear because many types of material and techniques are involved. PURPOSE: The purpose of this overview of systematic reviews of clinical studies was to assess the available evidence-based literature on the influence of associated clinical factors on the clinical performance (survival, failure rate, or success) of restored endodontically treated teeth. MATERIAL AND METHODS: PubMed, Scopus, and Web of Science were searched from inception until September 27, 2021, to identify systematic reviews. Two reviewers independently screened titles, abstracts, and full-text articles, and each reviewer extracted the data of half of the included studies. A single reviewer with an independent verifier completed the quality appraisal. A descriptive analysis of the collected data was made. RESULTS: A total of 36 systematic reviews fulfilled the inclusion criteria. The factors most assessed were the type of coronal restorative technique (n=22) and type of post (n=22). The results indicated that metal and fiber posts seem to present similar clinical performance, endocrowns could be a suitable restorative option, there is no evidence to confirm whether single crowns are better or worse than direct restoration, the maintenance of the coronal structure is a fundamental factor, and the ferrule effect is still a controversial topic. Most of the studies (n=30, 81%) presented a final Grading of Recommendations, Assessment, Development and Evaluations (GRADE) rating of "critically low." CONCLUSIONS: The post type does not appear to influence the clinical performance of restored endodontically treated teeth. However, conclusive evidence to suggest how different materials or techniques for restoring coronal tooth structure affect the clinical performance of such restorations, as well as the impact of the ferrule effect, is still lacking.

There is room for improvement in the use of scoping reviews in dentistry.

OBJECTIVE: To evaluate the reporting of authors' justifications for choosing the scoping review methodology in oral health. STUDY SELECTION, DATA AND SOURCE: This is a meta-research study about scoping reviews in dentistry. This study searched for reviews in PubMed and Scopus without year restrictions and restricted to English-language publications. Study selection was undertaken by two reviewers independently. Each of these reviewers extracted data from half of the included studies considering general study characteristics and scoping reviews objectives, as well as data about whether or not the authors clearly explained why they chose the scoping review framework. RESULTS: We included 184 articles. Ninety-seven of the reports did not provide a rationale as to why they chose the scoping review method (52.7%). Regarding the reported aims of the studies, 29.9% (n = 29/87) of the scoping reviews presented more than one. When comparing studies reporting the use of the PRISMA-ScR to those not reporting the PRISMA-ScR, there is no difference in the reporting of a clear explanation of why the authors used a scoping review method. CONCLUSION: There is room for improvement in how authors report their justifications for choosing the scoping review method. CLINICAL SIGNIFICANCE: Scoping reviews may be used by researchers who are unaware of this method. Educational initiatives should thus be encouraged.

Periodontitis and its associated factors in patients at the faculty of southern Brazil: a cross - sectional study

To verify the presence of periodontitis, its severity, and their association with associated factors based on medical records of patients who attended the Dental Clinic of the Faculty of Southern Brazil over 4 years. This is a cross-sectional study, which included 422 medical records of patients aged ≥ 18 years. The clinically analyzed data were: plaque index (PI),bleeding on probing (BOP), probing pocket depth (PPD), and clinical attachment level (CAL). Sociodemographic data, dental hygiene, harmful habits and chronic systemic diseases were described. Statistical analysis of binary logistic regression was used to verify the relationship between the severity of periodontitis and the exposure variables. The older adults [odds ratio (OR) = 2.36; 95% confidence interval (CI): 1.23-4.54 ­41 to 55 years and OR = 3.0; 95% CI: 1.49-6.09 ­56 to 87 years], and men (OR = 1.9; 95% CI: 1.18-3.14) showed higher chances of periodontitis severity. Smokers (OR = 3.54; 95% CI: 2.05-6.12), those with hypertension (OR = 2.11; 95% CI: 1.23-3.63) and with diabetes (OR = 2.10; 95% CI: 1.08-4.12) showed higher chances of developing advanced periodontitis. Advanced or severe periodontitis occurred in one-third of the patients. The findings showed that men, older adults, with systemic arterial hypertension, diabetes mellitus, and smokers are more susceptible to severe periodontitis.

How are meta-analyses being conducted and reported in dentistry? A meta-research study

Aim: This study aimed to evaluate how meta-analyses are conducted and reported in dentistry. Methods: We conducted a search to identify dentistry-related Systematic Reviews (SRs) indexed in PubMed in 2017 (from January 01 until December 31) and published in the English language. We included only SRs reporting at least one meta-analysis. The study selection followed the 4-phase flow set forth in the Preferred Reporting Items for Systematic Reviews and Meta-Analyses Statement (PRISMA), and it was independently conducted by two researchers. Data extraction was performed by one of three reviewers, and data related to conducting and reporting of the meta-analysis were collected. Descriptive data analysis was performed summarizing frequencies for categorical items or median and interquartile range for continuous data. Results: We included 214 SRs with meta-analyses. Most of the studies reported in the title that a meta-analysis was conducted. We identified three critical flaws in the included studies: Ninety (90) meta-analyses (43.1%) did not specify the primary outcome; most of the meta-analyses reported that a measure of statistical heterogeneity was used to justify the use of a fixed-effect or random-effects meta-analysis model (n=114, 58.5%); and a great part did not assess publication bias (n=106, 49.5%). Conclusion: We identified deficiencies in the reporting and conduct of meta-analysis in dentistry, suggesting that there is room for improvement. Educational approaches are necessary to improve the quality of such analyses and to avoid biased and imprecise results

Layering of discolored substrates with high-value opaque composites for CAD-CAM monolithic ceramics.

STATEMENT OF PROBLEM: Severely discolored substrates have been shown to limit the use of computer-aided design and computer-aided manufacturing (CAD-CAM) ceramic blocks because they provide insufficient color masking. PURPOSE: The purpose of the in vitro study was to evaluate the effect of a layer of high-value opaque composite resin over discolored substrates to determine its masking ability with CAD-CAM ceramics. MATERIAL AND METHODS: Six ceramic groups (n=10) were tested. A bilayer group of zirconia and porcelain served as the control. The CAD-CAM monolithic groups were translucent zirconia, zirconia-reinforced lithium silicate, lithium disilicate, leucite-reinforced glass-ceramic, and feldspathic ceramic. Five substrates were used: A1 (used as reference), A3.5, C4, and coppery and silvery metals. The substrates were separated as nonlayered or layered (with flowable or restorative opaque composite resins). The tested luting agents were white, opaque, and A1. Color differences (ΔE00) were assessed with the CIEDE2000 formula. A 2-way ANOVA (α=.05) was used to detect significant differences in ΔE00 among the groups for each substrate. The results were compared with acceptability (1.77) and perceptibility (0.81) thresholds. RESULTS: The flowable composite resin layer associated with A1 luting agent ensured ΔE00 lesser the than perceptibility thresholdwith the use of CAD-CAM monolithic ceramics, with the lowest values for zirconia-reinforced lithium silicate in substrates A3.5 (0.53) and C4 (0.32) and for leucite-reinforced glass-ceramic for coppery (0.49) and silvery (0.81) substrates (P<.001). The same benefit was observed when zirconia and porcelain was tested over the silvery substrate. The absence of substrate treatment only provided ΔE00 lesser than the acceptability threshold with CAD-CAM ceramics for the A3.5 background. CONCLUSIONS: The application of a flowable opaque composite resin and the use of a shaded luting agent ensure masking with CAD-CAM monolithic ceramics.

The mass production of systematic reviews about COVID-19: An analysis of PROSPERO records.

OBJECTIVE: This study aimed to assess the characteristics of different designs of systematic reviews (SRs) registered in the International Prospective Register of Systematic Reviews (PROSPERO) about COVID-19. METHODS: The search was performed in the PROSPERO database using the strategy proposed by the database and considered only human studies. The last date of the search was April 27, 2020. Full text of all records was accessed, and data were extracted by a single researcher, which was further double-checked by another researcher. A descriptive analysis was performed considering record characteristics using tables. RESULTS: We included 564 records from which the vast majority were registered as SRs (n = 513, 91%). In general, we found poor reporting and missing or confusing information, since 84% of the records (n = 474) did not report the full search that would be adopted, 16% (n = 90) did not report clearly the databases that would be used, and 49.1% (n = 277) did not report the number of primary outcomes. The main focus of most of the records involved clinical, epidemiological, complication, and laboratory characteristics (n = 173, 30.7%) or the treatment of COVID-19 (n = 138, 24.5%). CONCLUSION: A large number of SRs about COVID-19 have been conducted, and many of the assessed records were poorly reported and would be difficult to replicate. Besides, collected data points to an epidemic of redundant reviews on COVID-19.

Restorative preferences and choices of dentists and students for restoring endodontically treated teeth: A systematic review of survey studies.

STATEMENT OF PROBLEM: The best protocol to restore endodontically treated teeth is still unclear, with many factors to be considered, including the selection and necessity of a post, the type of coronal restoration, the amount of remaining coronal structure, and the type of luting agent. PURPOSE: The purpose of this systematic review was to assess the restorative preferences for endodontically treated teeth between dentists and dental students. MATERIAL AND METHODS: Survey studies, written in English, of dentists and dental students, which evaluated the use of intracanal posts and other restorative options for endodontically treated teeth, were selected. Searches were performed in the PubMed and SCOPUS databases without time restriction. Screening and data extraction were performed by 2 researchers independently. A standardized outline was used to extract the data (questions related to the theme and the response rate of each question on the survey), and the risk of bias was assessed. Descriptive analysis was performed of the collected information. RESULTS: Twenty-five articles were included. Most dentists who answered the surveys reported the time since graduation as 1 to 20 years (40%), and 44% were specialists. The most reported choices concerning the type of posts used were prefabricated posts (45.8%), cast metal posts (16.7%), and both posts (16.7%). The cast metal posts were cited more frequently in surveys published between 1994 and 2010, whereas prefabricated posts, both metal and glass fiber ones, were cited between 2006 and 2019. The preferred luting agent for intracanal posts was resin-based (47%). These choices seem to have been influenced by time and by the level of postgraduate training. CONCLUSIONS: Restorative preferences related to posts have changed over time, from the use of cast posts to prefabricated ones or the use of both posts and seem to be influenced by experience and postgraduate training.

Decontamination of N95 respirators against SARS-CoV-2: A scoping review.

OBJECTIVES: This scoping review aimed to map and compile the available evidence regarding the effectiveness of decontaminating N95 respirators against the novel coronavirus (SARS-CoV-2). DATA: We selected studies written in English assessing or discussing the decontamination strategies of N95 respirators against SARS-CoV-2. Two independent researchers performed the search and study screening. A descriptive analysis was carried out considering the study design of the included studies. SOURCES: PubMed, SCOPUS, and Preprint platforms (bioRxiv and medRxiv). STUDY SELECTION: We included 55 reports from PubMed and SCOPUS. Nine articles were letters to the editors, 21 were in vitro studies, 16 were literature reviews, and 9 were classified as other study designs. We included 37 preprints. Two articles were letters to the editors, 24 were in vitro studies, 3 were literature reviews, and 8 were classified as other study designs. In general, vaporized hydrogen peroxide and ultraviolet irradiation were the strategies most cited and most promising. However, there is a lack of evidence and consensus related to the best method of N95 respirator decontamination. CONCLUSION: The evidence regarding decontamination strategies of N95 respirators against SARS-CoV-2 remains scarce. Vaporized hydrogen peroxide and ultraviolet irradiation seem to be the current standard for N95 respirator decontamination. CLINICAL SIGNIFICANCE: Vaporized hydrogen peroxide and ultraviolet irradiation appear to be the most promising methods for N95 respirator decontamination.

The use of solvents for gutta-percha dissolution/removal during endodontic retreatments: A scoping review.

This scoping review study aimed to map the evidence about solvents' use for gutta-percha dissolution and removal during endodontic retreatments. The study protocol followed the Joanna Briggs Institute guidelines, available online (https://osf.io/5vy8n/). Reporting was based on PRISMA Extension for Scoping Reviews. We selected dentistry studies that considered the effectiveness of solvents in gutta-percha dissolution in endodontic retreatments and compared their performance to the use of instrumentation techniques without solvents. The search and study screening were performed in PubMed and Scopus databases by two independent researchers. A descriptive analysis considered the study design, method/technique used for obturation, method/technique used for instrumentation during retreatment, solvent solutions tested, exposure time, and main findings. A total of 41 studies were included. Despite that, most studies suggested that solvents' use may complicate root canal cleanliness, regardless of the type of instrumentation used, and facilitate the presence of gutta-percha remnants in the root surface. Thus, the use of solvents should be avoided and its use should only be considered if the previous working length was not possible to access without it. Despite that, high heterogeneity was observed, further studies are still encouraged comparing the performance and effects of different solvents in different clinical scenarios.

Novas perspectivas para reabilitação de dentes tratados endodonticamente / Novel perspectives for the rehabilitation of endodontically treated teeth

Vários fatores podem influenciar o desempenho clínico de dentes com tratamento endodôntico (DTE). Além disso diversas são as opções restauradoras indicadas em respeito a este cenário, em especial com o notório avanço de novas técnicas e tecnologias para uso clínico. Dentre estas corriqueiramente envolvem-se o uso de restaurações diretas (confeccionadas com resina composta), pinos metálicos ou de fibra de vidro, pinos pré-fabricados ou fresados, assim como restaurações indiretas compostas de coroas cerâmicas, inlays, onlays ou endocrowns; sempre com o foco na reabilitação funcional e estética do caso em tela. Neste trabalho, através de uma revisão narrativa, foram expostos conceitos relativos às modalidades restauradores que se advêm do uso de novas tecnologias na reabilitação de dentes tratados endodonticamente(AU)

Several factors may influence the clinical performance of endodontically treated teeth (ETT). In addition, there are several restorative options indicated regarding this scenario, especially with the notable advance of new techniques and technologies for clinical use. These routinely involve the use of direct restorations (made of composite resin), metal or fiberglass posts, prefabricated or milled posts, as also indirect restorations composed of ceramic crowns, inlays, onlays or endocrown; always focusing on functional and aesthetic rehabilitation of the case in hand. In this study, through a narrative review, concepts related to the restorative modalities that were introduced with the use of new technologies in the rehabilitation of endodontically treated teeth were discussed(AU)

Influence of Root Canal Preparation on Formation of Dentinal Microcracks: A Systematic Review.

The effect of root canal preparation technique on microcrack initiation is a controversial issue. This systematic review aimed to assess the role of root canal preparation techniques with different kinematics (manual, rotary, reciprocating, adaptive, self-adjusting file) on microcrack initiation. In vitro and in situ studies comparing the influence of at least two different root canal preparation techniques on the initiation of dentin microcracks were searched in PubMed/MEDLINE and SCOPUS up to June 5, 2018 without language and period restriction. Two authors independently reviewed all identified titles and abstracts for eligibility. Tables were generated to summarize the included studies, and the included studies were assessed for bias. Fifty-four (n=54) articles met the eligibility criteria. The results were classified according to the method used for microcrack evaluation, and most studies that used micro-computed tomography showed no formation of new cracks after root canal preparation. In general, the instrumentation techniques induced microcrack formation when the methods were destructive, irrespective of kinematics. In relation to the apex region, when the preparation working length was set as the root canal length subtracted of 1 mm, the risk of microcrack initiation reduces. The majority of the included studies had low risk of bias for all assessed domains. Our results seem to indicate that the various root canal preparation techniques considered in this study will not cause damage to the dental structure when adequately employed and the proper methodology is applied.

Influence of root canal preparation on formation of dentinal microcracks: a systematic review

Abstract The effect of root canal preparation technique on microcrack initiation is a controversial issue. This systematic review aimed to assess the role of root canal preparation techniques with different kinematics (manual, rotary, reciprocating, adaptive, self-adjusting file) on microcrack initiation. In vitro and in situ studies comparing the influence of at least two different root canal preparation techniques on the initiation of dentin microcracks were searched in PubMed/MEDLINE and SCOPUS up to June 5, 2018 without language and period restriction. Two authors independently reviewed all identified titles and abstracts for eligibility. Tables were generated to summarize the included studies, and the included studies were assessed for bias. Fifty-four (n=54) articles met the eligibility criteria. The results were classified according to the method used for microcrack evaluation, and most studies that used micro-computed tomography showed no formation of new cracks after root canal preparation. In general, the instrumentation techniques induced microcrack formation when the methods were destructive, irrespective of kinematics. In relation to the apex region, when the preparation working length was set as the root canal length subtracted of 1 mm, the risk of microcrack initiation reduces. The majority of the included studies had low risk of bias for all assessed domains. Our results seem to indicate that the various root canal preparation techniques considered in this study will not cause damage to the dental structure when adequately employed and the proper methodology is applied.

Resumo O efeito da técnica de preparo do canal radicular na iniciação e/ou propagação de microfissuras dentinárias é um tema controverso. Essa revisão sistemática teve como objetivo avaliar o papel das técnicas de preparo do canal radicular com diferentes cinemáticas (manual, rotatória, reciprocante, adaptativa e self-adjusting file) na iniciação e/ou propagação de microfissuras dentinárias. Estudos in vitro e in situ comparando a influência de pelo menos duas técnicas diferentes de preparo do canal radicular foram identificados no PubMed/MEDLINE e SCOPUS até 05 de junho de 2018 sem restrição de idioma e tempo. Dois autores revisaram de maneira independente todos títulos e resumos para elegibilidade dos estudos. Tabelas foram criadas para sumarizar os estudos incluídos e os estudos foram avaliados quanto ao risco de viés. Cinquenta e quatro (54) estudos enquadraram-se nos critérios de elegibilidade. Os resultados foram classificados de acordo com o método utilizado para avaliação das microfissuras. A maioria dos estudos que utilizaram micro-tomografia não demonstraram formação de novas microfissuras após preparo do canal radicular. Em geral, técnicas de instrumentação induziram formação de microfissuras quando os métodos de avaliação foram destrutivos, independente da cinemática. Em relação a região do ápice, quando comprimento de trabalho foi definido como o comprimento do canal menos 1 mm, o risco de indução de microfissuras é reduzido. A maioria dos estudos incluídos apresentaram baixo risco de viés para todos os domínios apresentados. Nossos resultados parecem indicar que as diferentes técnicas de preparo do canal radicular não causam danos a estrutura dental quando adequadamente utilizadas e a metodologia adequada é utilizada.