Publications by authors named "João Miguel Santos"

16 Publications

  • Page 1 of 1

Influence of Preoperative Pulp Inflammation in the Outcome of Full Pulpotomy Using a Dog Model.

J Endod 2021 Sep 3;47(9):1417-1426. Epub 2021 Jul 3.

Institute of Endodontics, Faculty of Medicine, University of Coimbra, Coimbra, Portugal; Center for Innovation and Research in Oral Sciences, Faculty of Medicine, University of Coimbra, Coimbra, Portugal.

Introduction: This study aimed to evaluate the impact of preoperative pulp inflammation on the histologic outcome of full pulpotomy performed in mature permanent posterior teeth using 4 different biomaterials.

Methods: Five beagle dogs (providing a total of 120 roots) were selected. Dentin exposure was performed in teeth from the second and third quadrants. One week later, full pulpotomy procedures were performed using 4 different bioactive materials (ProRoot MTA [MTA], TotalFill BC Putty [BC], Biodentine [BIO], and an experimental cement [ie, pulp capping material]). The hemostasis time was registered. After 14 weeks, the animals were killed. Pulp-dentin tissues were histologically and radiographically assessed. The significance level was set at .05.

Results: Teeth with previously exposed dentin revealed a statistically significant increase in the time required to achieve hemostasis (P < .001), therefore confirming the pulp inflammation status induced by 1-week exposure of occlusal dentin before performing full pulpotomy. There was no radiographic evidence of root resorption, periapical radiolucency, or lamina dura alterations. No statistically significant differences were observed between normal and inflamed pulp regardless of the evaluated histologic parameters. Moreover, histologic data concerning calcified barrier formation and the pulp tissue response show better results for BIO without statistical differences compared with MTA or BC (P > .05). The pulp capping material presented a lower performance, with statistically significant differences being detected in regard to the remaining 3 tested materials (P < .001).

Conclusions: Radiographic and histologic outcomes of full pulpotomy are not jeopardized by short-term preoperative pulp inflammation. Moreover, BIO, MTA, and BC cements present suitable alternatives to be used as pulp capping agents.
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http://dx.doi.org/10.1016/j.joen.2021.06.018DOI Listing
September 2021

Vital Pulp Therapy in Permanent Mature Posterior Teeth with Symptomatic Irreversible Pulpitis: A Systematic Review of Treatment Outcomes.

Medicina (Kaunas) 2021 Jun 3;57(6). Epub 2021 Jun 3.

MSc Endodontics Program, Faculty of Dentistry, University of Toronto, Toronto, ON M5G 1G6, Canada.

: Symptomatic irreversible pulpitis in permanent mature teeth is a common indication for nonsurgical root canal treatment (NSRCT), but contemporary studies have reported on vital pulp therapy (VPT) applied in such teeth as a less invasive treatment. This systematic review assessed the outcomes of VPT, including partial and full pulpotomy performed with hydraulic calcium silicate cements (HCSCs) in permanent mature posterior teeth diagnosed with symptomatic irreversible pulpitis. : The PRISMA guidelines were followed. The search strategy included PubMed, EMBASE, Cochrane library and grey literature electronic databases. The quality assessment of the identified studies followed the Cochrane Collaboration Risk of Bias, ROBINS-I and Newcastle-Ottawa Scale tools. : The search of primary databases identified 142 articles, of which 9 randomized controlled trials and 3 prospective cohort studies were selected for review. The risk-of-bias was assessed as 'high' or 'serious', 'fair', and 'low' for three, seven and two articles, respectively. One to five years after VPT using HCSCs, the success rates mostly ranged from 78 to 90%. Based on two articles, the outcomes of the VPT and NSRCT were comparable at one and five years. Despite the necessity for the intra-operative pulp assessment in VPT procedures, the majority of the studies did not fully report on this step or on the time needed to achieve hemostasis. Small sample sizes, of under 23 teeth, were reported in three studies. : The reviewed 12 articles reported favorable outcomes of the VPT performed with HCSCs in permanent mature posterior teeth with symptomatic irreversible pulpitis, with radiographic success in the range of 81 to 90%. Two articles suggested comparable outcomes of the VPT and root canal treatment. Universal case selection and outcome criteria needs to be established for VPT when considered as an alternative to NSRCT. This evidence supports the need for further research comparing longer-term outcomes of both of the treatment modalities.
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http://dx.doi.org/10.3390/medicina57060573DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8228104PMC
June 2021

Regeneration of pulp-dentin complex using human stem cells of the apical papilla: in vivo interaction with two bioactive materials.

Clin Oral Investig 2021 Sep 25;25(9):5317-5329. Epub 2021 Feb 25.

Institute of Endodontics, Faculty of Medicine, University of Coimbra, Coimbra, Portugal.

Objectives: To compare the regenerative properties of human stem cells of the apical papilla (SCAPs) embedded in a platelet-rich plasma (PRP) scaffold, when implanted in vivo using an organotypic model composed of human root segments, with or without the presence of the bioactive cements - ProRoot MTA or Biodentine.

Material And Methods: SCAPs were isolated from third molars with incomplete rhizogenesis and expanded and characterized in vitro using stem cell and surface markers. The pluripotency of these cells was also assessed using adipogenic, chondrogenic, and osteogenic differentiation protocols. SCAPs together with a scaffold of PRP were added to the root segment lumen and the organotypic model implanted on the dorsal region of immunodeficient rats for a period of 4 months.

Results: Presence of SCAPs induced de novo formation of dentin-like and pulp-like tissue. A barrier of either ProRoot MTA or Biodentine did not significantly affect the fraction of sections from roots segments observed to contain deposition of hard material (P > 0.05). However, the area of newly deposited dentin was significantly greater in segments containing a barrier of Biodentine compared with ProRoot MTA (P < 0.001).

Conclusions And Clinical Relevance: SCAPs offer a viable alternative to other dental stem cells (DSCs) in their regenerative properties when enclosed in the microenvironment of human tooth roots. The present study also suggests that the presence of bioactive materials does not hinder or impede the formation of new hard tissues, but the presence of Biodentine may promote greater mineralized tissue deposition.
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http://dx.doi.org/10.1007/s00784-021-03840-9DOI Listing
September 2021

Subcutaneous Implantation Assessment of New Calcium-Silicate Based Sealer for Warm Obturation.

Biomedicines 2021 Jan 1;9(1). Epub 2021 Jan 1.

Coimbra Institute for Clinical and Biomedical Research (iCBR) and Institute of Biophysics, Faculty of Medicine, University of Coimbra, 3000-548 Coimbra, Portugal.

Calcium silicate-based sealers were recently introduced as a new class of endodontic sealers, with potential further benefits due to their bioactivity. The aim of this study was to evaluate the biocompatibility of two new hydraulic calcium silicate-based sealers, TotalFill BC Sealer (FKG, La Chaux-des-Fonds, Switzerland) and TotalFill BC Sealer HiFlow (FKG, La Chaux-des-Fonds, Switzerland) through subcutaneous implantation in connective tissue of rats. Subcutaneous implantation was performed in 16 young Wistar rats. Four polyethylene tubes were implanted in each animal, one empty to serve as a control, and three filled with tested sealers: AH Plus as reference (Dentsply DeTrey, Konstanz, Germany), TotalFill BC Sealer (BC) and TotalFill BC Sealer HiFlow (HiFlow). Eight rats were euthanized at 8 days and the remaining eight at 30 days. Hematoxylin-eosin staining was used to score the inflammatory reaction, macrophage infiltrate and to measure the thickness of the fibrous capsule. von Kossa staining was performed to evaluate the mineralization level. Kruskal-Wallis test followed by Dunn's test was used to analyze non-parametric data. To analyze the influence of the implantation time within each material, a Mann-Whitney U test was performed. At eight days post-implantation, AH Plus induced a more intense inflammatory reaction when compared both with the control ( ≤ 0.001) and BC ( ≤ 0.01). HiFlow presented a higher score of macrophage infiltrate than control ( ≤ 0.01) and BC ( ≤ 0.05). The fibrous capsule thickness in this period was significantly higher for the BC group when compared to control ( ≤ 0.01) and AH Plus ( ≤ 0.05). The mineralization potential was higher for the HiFlow group when compared with the control ( ≤ 0.001) and AH Plus ( ≤ 0.001). At 30 days post-implantation, the score for the inflammatory reaction remained higher for the AH Plus group when compared both to control ( ≤ 0.01) and BC ( ≤ 0.001). The macrophage infiltrate of the HiFlow was significantly higher than control ( ≤ 0.001) and AH Plus groups ( ≤ 0.01), additionally, the fibrous capsule of the BC ( ≤ 0.001) and HiFlow ( ≤ 0.01) groups were both thicker than control. Mineralization potential was observed only on BC ( ≤ 0.05) and HiFlow groups ( ≤ 0.001), when compared to control). BC exhibited the best biocompatibility performance of all tested sealers and HiFlow provided the greatest induction of mineralized tissues. Both TotalFill BC Sealer and TotalFill BC Sealer HiFlow are biocompatible and show potential bioactivity when implanted in the subcutaneous tissue. Bioactivity was not found in AH Plus.
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http://dx.doi.org/10.3390/biomedicines9010024DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7824331PMC
January 2021

Effect of restorative timing on shear bond strength of composite resin/calcium silicate-based cements adhesive interfaces.

Clin Oral Investig 2021 May 12;25(5):3131-3139. Epub 2020 Oct 12.

Center for Innovation and Research in Oral Sciences (CIROS), Faculty of Medicine, University of Coimbra, Coimbra, Portugal.

Objectives: The aim of this study was to evaluate the shear bond strength inherent to immediate and delayed definitive composite resin restorations, over three different biomaterials.

Methods: Fifty-four aluminum blocks were randomly assigned to six experimental groups (n = 9) according to the biomaterial (Biodentine, TotalFill BC Putty, or PCM) and restoration timing (immediate or 7 days delayed). Regarding the restorative procedures, a two-step self-etch bonding system (Clearfil SE Bond) was applied and subsequently restored using a flowable composite resin (SDR). After shear bond strength testing, fracture pattern analysis was performed. The significance level was set at α = 0.05.

Results: Within the immediate groups, Biodentine showed the highest mean shear bond strength value, with no statistically significant differences (P > 0.05) being detected when compared with both TotalFill (P = 0.072) and PCM (P = 0.232) groups. Regarding the delayed restoration groups, Biodentine and TotalFill presented the highest mean shear bond strength value, with statistical differences when compared with PCM (P = 0.002 and P = 0.043, respectively). No statistically significant differences (P > 0.05) were verified between both immediate and delayed groups for each tested biomaterial. Also, a statistically significant association was found between the fracture type and the biomaterial (P < 0.001).

Conclusions And Clinical Relevance: Our findings suggest that all tested biomaterials present suitable alternatives which allow to perform restorative procedures immediately after pulp capping biomaterial placement (3 or 12 min, depending on the bioactive cement), therefore requiring one single appointment to complete the procedure. Biodentine and TotalFill BC Putty have shown superior shear bond strength results when compared with PCM, within a delayed timeframe (7 days).
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http://dx.doi.org/10.1007/s00784-020-03640-7DOI Listing
May 2021

Evaluation of Root-End Preparation with Two Different Endodontic Microsurgery Ultrasonic Tips.

Biomedicines 2020 Sep 28;8(10). Epub 2020 Sep 28.

Institute of Endodontics, Faculty of Medicine, University of Coimbra, 3000-075 Coimbra, Portugal.

The aim of this study is to compare root-end preparation performed with two different ultrasonic tips-CVDentus and NSK-and respective time requirements. After root-end resection, 32 teeth were randomly divided in two groups, according to the ultrasonic tip used for root-end preparation. Preparation time was recorded. Photomicrographs were taken to assess the following parameters: root surface microcracking, marginal integrity and presence of debris. One ultrasonic tip from each group was analyzed through scanning electron microscopy before and after root-end preparation. The significance level was set at α = 0.05. Incidence of microcracks in both groups was 12.5%. Solely intracanal microcracking was found, consistently positioned within the widest side of the remaining dentine. No statistically significant differences were verified between both experimental groups regarding marginal integrity ( = 0.102) and preparation time ( = 0.780), whereas statistical differences ( = 0.003) were found concerning the presence of debris (the minimum registered score was mostly verified in CVDentus group). NSK tips showed major morphological changes, with extensive surface wear and noticeable loss of particles, which was not verified on CVDentus tips. Our findings suggest significant differences regarding root-end preparation walls quality, with CVDentus tips showing better results. Concerning microcracking, as well as preparation time and marginal integrity, both ultrasonic tips showed similar results. Qualitative analysis exposed NSK tips major morphological changes and wear after use, which was not verified on CVDentus tips.
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http://dx.doi.org/10.3390/biomedicines8100383DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7601836PMC
September 2020

Long-Term Prognosis of Endodontic Microsurgery-A Systematic Review and Meta-Analysis.

Medicina (Kaunas) 2020 Sep 3;56(9). Epub 2020 Sep 3.

Institute of Endodontics, Faculty of Medicine, University of Coimbra, 3000-132 Coimbra, Portugal.

The long-term outcome of endodontic microsurgery (EMS) performed on root-filled teeth affected by post-treatment apical periodontitis (AP) has been a matter of debate, re-launched by the introduction of novel root-end filling materials which have been proven to improve the short-term outcome of EMS. The purpose of this systematic review and meta-analysis is to evaluate the clinical and radiographic long-term outcome of endodontic microsurgery in teeth diagnosed with secondary AP through radiographic evaluation. This systematic review and meta-analysis followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Inclusion and exclusion criteria were defined a priori to select the best longitudinal evidence. Only randomized clinical trials (RCT) and prospective clinical studies (PCS), with a follow-up ≥ 2-year, and exhibiting well-established clinical and radiographic outcome criteria, were selected. A total of 573 articles were obtained, from which 10 fulfill inclusion criteria: 6 PCS and 4 RCT. Meta-analysis showed a pooled proportion of success rate of 91.3%, from an overall amount of 453 treated teeth included in RCT; from overall 839 included teeth in PCS, a pooled success rate of 78.4% was observed, with the follow-up time ranging from 2 to 13-years. Survival rate outcomes varied from 79 to 100% for the same follow-up period. Five prognostic factors with influence on the outcome were disclosed: smoking habits, tooth location and type, absence/presence of dentinal defects, interproximal bone level, and root-end filling material. High success rates and predictable results can be expected when EMS is performed by trained endodontists, allowing good prognosis and preservation of teeth affected by secondary AP.
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http://dx.doi.org/10.3390/medicina56090447DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7558840PMC
September 2020

An Insight into Advanced Approaches for Photosensitizer Optimization in Endodontics-A Critical Review.

J Funct Biomater 2019 Sep 30;10(4). Epub 2019 Sep 30.

Institute of Endodontics, Faculty of Medicine, University of Coimbra, 3000-075 Coimbra, Portugal.

Apical periodontitis is a biofilm-mediated disease; therefore, an antimicrobial approach is essential to cure or prevent its development. In the quest for efficient strategies to achieve this objective, antimicrobial photodynamic therapy (aPDT) has emerged as an alternative to classical endodontic irrigation solutions and antibiotics. The aim of the present critical review is to summarize the available evidence on photosensitizers (PSs) which has been confirmed in numerous studies from diverse areas combined with several antimicrobial strategies, as well as emerging options in order to optimize their properties and effects that might be translational and useful in the near future in basic endodontic research. Published data notably support the need for continuing the search for an ideal endodontic photosensitizer, that is, one which acts as an excellent antimicrobial agent without causing toxicity to the human host cells or presenting the risk of tooth discoloration. The current literature on experimental studies mainly relies on assessment of mixed disinfection protocols, combining approaches which are already available with aPDT as an adjunct therapy. In this review, several approaches concerning aPDT efficiency are appraised, such as the use of bacteriophages, biopolymers, drug and light delivery systems, efflux pump inhibitors, negative pressure systems, and peptides. The authors also analyzed their combination with other approaches for aPDT improvement, such as sonodynamic therapy. All of the aforementioned techniques have already been tested, and we highlight the biological challenges of each formulation, predicting that the collected information may encourage the development of other effective photoactive materials, in addition to being useful in endodontic basic research. Moreover, special attention is dedicated to studies on detailed conditions, aPDT features with a focus on PS enhancer strategies, and the respective final antimicrobial outcomes. From all the mentioned approaches, the two which are most widely discussed and which show the most promising outcomes for endodontic purposes are drug delivery systems (with strong development in nanoparticles) and PS solubilizers.
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http://dx.doi.org/10.3390/jfb10040044DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6963755PMC
September 2019

Six-Month Color Stability Assessment of Two Calcium Silicate-Based Cements Used in Regenerative Endodontic Procedures.

J Funct Biomater 2019 Feb 28;10(1). Epub 2019 Feb 28.

Institute of Operative Dentistry, Faculty of Medicine, University of Coimbra, 3000-075 Coimbra, Portugal.

Aim: The purpose of the present study is to assess the color stability of two calcium silicate-based cements (CSCs) used in regenerative endodontic procedures (REPs).

Methods: A total of 40 acrylic single-rooted transparent teeth, with immature apex, were used. Root canals were filled up to 3 mm below the level of the cementoenamel junction, with either saline solution (Mineral Trioxide Aggregate (MTA)/saline and Biodentine/saline) or blood (MTA/blood and Biodentine/blood). Subsequently, ProRoot MTA or Biodentine was placed in the root canal to create a cervical barrier. Color measurement was carried out at four different evaluation periods (3 h, 72 h, 7 days, and 6 months). Shade analysis within the L* a* b* color space was performed and color variation (∆E) calculated. The significance level for statistical analysis was set at < 0.05.

Results: The four groups showed a significant decrease in L* values over time. The ΔE value increased over time for all groups but was not statistically significant for the Biodentine/blood group. Two-way ANOVA showed no interaction between the CSC and treatment (contact with saline solution or blood). CSC used was the factor responsible for ΔE over time, inducing statistically significant color variations from T to T ( = 0.04) and T to T ( < 0.01). After 6 months, MTA/saline had 5.08 ( = 0.001) higher ΔE than Biodentine/Saline and the MTA/blood had 3.65 ( = 0.009) higher than Biodentine/blood.

Conclusions: After 6 months, regardless of blood exposure, Biodentine exhibits superior color stability compared to MTA. Biodentine might be a suitable alternative to MTA as a cervical barrier material in REPs.
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http://dx.doi.org/10.3390/jfb10010014DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6462979PMC
February 2019

Effects of a New Bioceramic Material on Human Apical Papilla Cells.

J Funct Biomater 2018 Dec 16;9(4). Epub 2018 Dec 16.

Institute of Endodontics, Faculty of Medicine, University of Coimbra, Coimbra 3000-075 Portugal.

Background: The development of materials with bioregenerative properties is critically important for vital pulp therapies and regenerative endodontic procedures. The aim of this study was to evaluate the cytocompatibility and cytotoxicity of a new endodontic biomaterial, PulpGuard, in comparison with two other biomaterials widely used in endodontic procedures, ProRoot Mineral Trioxide Aggregate (MTA) and Biodentine.

Methods: Apical papilla cells (APCs) were isolated from third molars with incomplete rhizogenesis from patients with orthodontic indication for dental extraction. Cultured APCs were incubated for 24, 48, or 72 h with different dilutions of eluates prepared from the three materials. Cellular viability, mobility, and proliferation were assessed in vitro using the Alamar Blue assay and a wound-healing test. The cells were also cultured in direct contact with the surface of each material. These were then analyzed via Scanning Electron Microscopy (SEM), and the surface chemical composition was determined by Energy-Dispersive Spectroscopy (EDS).

Results: Cells incubated in the presence of eluates extracted from ProRoot MTA and PulpGuard presented rates of viability comparable to those of control cells; in contrast, undiluted Biodentine eluates induced a significant reduction of cellular viability. The wound-healing assay revealed that eluates from ProRoot MTA and PulpGuard allowed for unhindered cellular migration and proliferation. Cellular adhesion was observed on the surface of all materials tested. Consistent with their disclosed composition, EDS analysis found high relative abundance of calcium in Biodentine and ProRoot MTA and high abundance of silicon in PulpGuard. Significant amounts of zinc and calcium were also present in PulpGuard discs. Concerning solubility, Biodentine and ProRoot MTA presented mild weight loss after eluate extraction, while PulpGuard discs showed significant water uptake.

Conclusions: PulpGuard displayed a good in vitro cytocompatibility profile and did not significantly affect the proliferation and migration rates of APCs. Cells cultured in the presence of PulpGuard eluates displayed a similar profile to those cultured with eluates from the widely used endodontic cement ProRoot MTA.
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http://dx.doi.org/10.3390/jfb9040074DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6306901PMC
December 2018

Cyclic fatigue resistance of three rotary file systems in a dynamic model after immersion in sodium hypochlorite.

Odontology 2019 Jul 12;107(3):324-332. Epub 2018 Dec 12.

Institute of Endodontics, Faculty of Medicine, University of Coimbra, Coimbra, Portugal.

To evaluate the effect of immersion in 3% sodium hypochlorite solution in the resistance to cyclic fatigue of three nickel-titanium (NiTi) rotary file systems, ProTaper Next (PTN), Hyflex CM (CM), and Hyflex EDM (EDM), in a mechanical model featuring axial movement. Ninety instruments of three different NiTi rotary file systems, PTN (size 25, 0.06 taper), CM (25, 0.06), and EDM (25/~, variable taper), were randomly divided according to a 3 × 3 factorial design and tested under dynamic immersion in a 3% NaOCl solution (1 or 5 min) or without immersion, making a total of 9 groups (n = 10). Files were tested in an artificial root canal with 45° angle and 5 mm radius apical curvature being submitted to back-and-forth movements until fracture. Statistical analysis was performed using two-way factorial ANOVA with Bonferroni post-hoc tests, at a significance level of 5%. Instruments were evaluated for reliability using a Weilbull approach. Regardless of the immersion treatment, PTN had on average 1200 ± 178 cycles to fracture, CM had 1949 ± 362, and EDM had 5573 ± 853, which was a significantly different (P < 0.01). The NaOCl immersion promoted a significant reduction in the mean number of cycles to fracture (P = 0.01), and was reflected in a significant reduction of the characteristic life of the instruments of the CM end EDM groups. Within this study conditions, EDM instruments performed better to cyclic fatigue followed by CM and then PTN. Immersion in NaOCl decreased the resistance to cyclic fatigue of all tested instruments, but affected more those manufactured from CM wire.
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http://dx.doi.org/10.1007/s10266-018-0401-2DOI Listing
July 2019

Root Resorption Classifications: A Narrative Review and a Clinical Aid Proposal for Routine Assessment.

Eur Endod J 2018 21;3(3):134-145. Epub 2018 Nov 21.

Department of Dentistry, Faculty of Medicine, University of Coimbra, Portugal.

Root resorption (RR) refers to noninfectious damage related to the loss of hard and soft dental tissue that results from clastic cell activity. It is observed as a pathologic process that is predominantly asymptomatic in the permanent dentition and physiological during the shedding of primary teeth. Roots are protected by unmineralized organic cementoid and predentine. RR occurs because of the inability of the clastic cells to adhere to unmineralized surfaces. Since the first RR classification was described by Andreasen in the 1970s, several classifications have been proposed with diverse terminology. A narrative literature review was undertaken on the current classification, diagnosis, pathophysiology, and treatment of RR. A bibliographic search resulted in 434 titles and abstracts, and from those, 17 articles were obtained that alluded to 15 RR classifications. A total of 28 articles that met the inclusion criteria were included. Results showed that Andreasen's classification is the most widely used for classifying RR. In terms of epidemiologic data, studies are scarce, although RR pathophysiology is well described in the literature. Overall clinical guidelines are summarized in a new RR classification diagram. The choice of RR treatment application should be in line with the RR type and the dentist's experience. However, an earlier and correct diagnosis will significantly improve final outcomes and long-term prognosis, especially with the current evolution of advanced imaging techniques, such as cone-beam computed tomography and bioceramic-based endodontic sealers.
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http://dx.doi.org/10.14744/eej.2018.33043DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7006572PMC
November 2018

Does Delayed Restoration Improve Shear Bond Strength of Different Restorative Protocols to Calcium Silicate-Based Cements?

Materials (Basel) 2018 Nov 8;11(11). Epub 2018 Nov 8.

Department of Dentistry, Faculty of Medicine, University of Coimbra, 3000-075 Coimbra, Portugal.

The purpose of the present study was to assess the proper time to perform a restoration (immediately or delayed) after placement of two calcium silicate-based cements (CSCs) and to test the performance of two different restorative protocols regarding shear bond strength (SBS). Seventy-five acrylic blocks were randomly divided into five groups ( = 15). Specimens were filled with either ProRoot MTA (Dentsply Tulsa Dental) or Biodentine (Septodont). The restoration was performed at an immediate (12 min) or delayed (seven days) timeframe, using a resin-based flowable composite (SDR) (bonded to the CSC using a universal bonding system) or glass ionomer cement (GIC) as restorative materials. SBS was measured using a universal testing machine. Fractured surfaces were evaluated, and the pattern was registered. Statistical analysis was performed using the Dunn⁻Sidak post hoc test ( < 0.05). Biodentine/immediate SDR showed the highest mean SBS value (4.44 MPa), with statistically significant differences when compared to mineral trioxide aggregate (MTA)/GIC (1.14 MPa) and MTA/immediate SDR (1.33 MPa). MTA/GIC and MTA/immediate SDR did not present significant differences regarding SBS. No statistical differences were verified concerning mean SBS between both CSCs within the 7 day groups. MTA/delayed SDR (3.86 MPa) presented statistical differences compared to MTA/immediate SDR, whereas no differences were observed regarding Biodentine performance (Biodentine/immediate SDR and Biodentine/delayed SDR (3.09 MPa)). Bonding procedures directly on top of MTA might be preferably performed at a delayed timeframe, whereas Biodentine might allow for immediate restoration.
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http://dx.doi.org/10.3390/ma11112216DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6265959PMC
November 2018

Is the chlorophyll derivative Zn(II)eMe a good photosensitizer to be used in root canal disinfection?

Photodiagnosis Photodyn Ther 2018 Jun 21;22:205-211. Epub 2018 Apr 21.

FMUC, Faculty of Medicine, University of Coimbra, Portugal; FMUC, Department of Dentistry, Faculty of Medicine, University of Coimbra, Portugal; CNC, Centre for Neuroscience and Cell Biology, University of Coimbra, Portugal. Electronic address:

Background: The aim of this study was to assess antimicrobial efficacy and cytotoxic outcomes of a chlorophyll based photosensitizer (PS) Zn(II)chlorin e methyl ester (Zn(II)eMe), when applied to human dentin discs and root blocks infected with 48 h biofilms. The results were compared with the ones obtained with FotoSan® (commercial Toluidine Blue O formulation) and 3% sodium hypochlorite (NaOCl).

Methodology: Dentin and root blocks were infected with mixed biofilms of Enterococcus faecalis and Candida albicans; exposed for 15 min to 0.1 mg/mL of Zn(II)eMe or Fotosan and then irradiated with red light (627 nm, 75 mW, 3150 J/cm) for 90 s or treated with NaOCl. Biofilm removal was calculated with safranin red assay and biofilm cells viability with XTT® assay. The PSs cytotoxicity was evaluated over human apical papilla primary cell line (hAPCs) with AlamarBlue® assay and cell morphology assessed with widefield fluorescence microscopy.

Results: At dentin discs, the chlorophyll derivative performed better in biofilm removal (59.1%) than FotoSan® agent (57.5%), however, with lower efficacy than NaOCl (68.1%) (P = 0.0185). Conversely, at the root block, the chlorophyll Zn(II)eMe (79.7%) present better antimicrobial efficacy than NaOCl (75.5%) and the disinfection pattern was more consistent at inner and outer samples for the former. No dark or photoinduced cytotoxic outcomes were detected for Zn(II)eMe over human cells at 24 and 48 h when compared with other PSs (FotoSan, Rose Bengal and 5,10,15,20-tetrakis(1-methylpyridinium-4-yl)porphyrin - TMPyP).

Conclusions: The chlorophyll derivative Zn(II)eMe showed adequate antimicrobial efficacy, performing better in mixed biofilm removal than FotoSan in both experimental conditions. No cytotoxic effects over human apical papilla cells were identified for this chlorophyll derivative, subsequently it deserves further evaluation to assess its potential use in endodontic therapy.
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http://dx.doi.org/10.1016/j.pdpdt.2018.04.009DOI Listing
June 2018

1-year In Vitro Evaluation of Tooth Discoloration Induced by 2 Calcium Silicate-based Cements.

J Endod 2016 Sep 3;42(9):1403-7. Epub 2016 Aug 3.

Dentistry Department, Faculty of Medicine, University of Coimbra, Coimbra, Portugal.

Introduction: The purpose of this study was to compare tooth discoloration that occurs in teeth filled with ProRoot MTA (DENTSPLY Tulsa Dental Specialties, Tulsa, OK) or Biodentine (Septodont, Saint Maur des Fossés, France) over the course of 1 year.

Methods: Twenty-eight intact premolars were resected 2 mm apical to the cementoenamel junction and the pulp tissues extirpated via the cervical cut. After the preparation of occlusal access to the pulp chamber, specimens were assigned into 4 groups according to a stratified randomization sampling process: group 1, negative control (dry sterile cotton pellet); group 2, positive control (blood-moistened cotton pellet); group 3, ProRoot WMTA (DENTSPLY Tulsa Dental Specialties); and group 4, Biodentine. The experimental materials were condensed into the crowns and the access sealed with glass ionomer restorative cement. Color was assessed at baseline (before placement of the materials), immediately after material filling, after 6 weeks of storage, and after 1 year using the Commission International de I'Eclairage L*a*b* system. Change in color, ΔE, was compared among groups and over time using analysis of variance.

Results: The 4 groups showed a significant decrease in L* values over time. Differences between Biodentine and WMTA were detected after 1 year, with the greater variation associated with WMTA (P = .001). The 4 groups presented a significant increase in ΔE from baseline to 1 year. All groups revealed perceptible color changes (ΔE > 2.3) between immediately after material filling and after 6 weeks and after 6 weeks and 1 year. After 1 year, no differences could be detected between Biodentine and WMTA.

Conclusions: Delayed tooth discoloration was detected for the 2 materials at the 1-year evaluation, but it was more evident for ProRoot MTA than Biodentine. Luminance was the most affected parameter, with a higher decrease for ProRoot MTA.
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http://dx.doi.org/10.1016/j.joen.2016.06.012DOI Listing
September 2016

In vivo biocompatibility of Resilon compared with gutta-percha in a pre-clinical model.

Dent Res J (Isfahan) 2013 Sep;10(5):652-8

Department of Dental Medicine, Stomatology and Maxillofacial Surgery, Faculty of Medicine of the University of Coimbra, Av. Bissaya Barreto, 3030-005, Coimbra, Portugal.

Background: The aim of this study was to investigate in vivo biocompatibility of Resilon, compared with gutta-percha, at short and long-term following implantation in a rat subcutaneous implantation model.

Materials And Methods: Male Wistar rats were implanted subcutaneously with either Resilon or gutta-percha or were sham controls. Tissues were harvested at 8 days or 60 days after implantation and were evaluated histologically for inflammation and fibrous encapsulation. The severity of histologic injury, scored on a scale of 0-4 and quantitative analysis of the capsule wall thickness were determined for statistical analysis. Data were analyzed by Student t-test, one-way analysis of variance, Kruskal-Wallis or Mann-Whitney's tests as appropriate. A value of P ≤ 0.05 was considered statistically significant.

Results: No behavioral changes or visible signs of physical impairment were observed at 8 days or 60 days post-implantation. Histopathologic observation of the implanted sites at each time-point showed that both Resilon and gutta-percha implants induced foreign body reaction, showing minimal to mild inflammatory reactions in most cases, which diminished significantly with time. Compared with gutta-percha, the capsule wall was thinner (P < 0.05) after Resilon implantation at day 8 and significantly (P = 0.01) thicker at day 60. In addition, capsule wall thickness showed a trend to increase with time after implantation in the Resilon groups (P < 0.05), opposed to the significant decrease (P = 0.016) observed after implantation in the gutta-percha groups, suggesting lesser long-term biocompatibility of Resilon.

Conclusion: Our findings validate Resilon as an in vivo biocompatible material. However, our data suggest that long-term biocompatibility of Resilon, despite validated, is inferior to that of gutta-percha control.
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http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3858742PMC
September 2013
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