Internal Adaptation of Composite Fillings Made Using Universal Adhesives-A Micro-Computed Tomography Analysis.

This study aimed to evaluate internal tooth-filling interfaces of composite fillings made using universal adhesives using micro-computed tomography (µCT). Sixty class V cavities were randomly assigned into six groups: Peak Universal etch and rinse (PER), Peak Universal self-etch (PSE), Adhese Universal etch and rinse (AER), and Adhese Universal self-etch (ASE). Two further adhesives considered gold standards were used as control groups: OptiBond FL (OER) for the etch and rinse technique and Clearfil SE for the self-etch technique (CSE). All teeth were subjected to thermomechanical loading and four-year water storage. Next, they were analyzed using µCT to investigate the internal tooth-filling interfaces. The proportions between the gap volume (GV) at the tooth-filling interface and the volume of applied composite filling (FV), between the gap and cavity volumes (CV), and between the gap volumes at the tooth-filling interface of the external (EGV) and internal (IGV) parts were calculated. Adhese Universal achieved the significantly lowest gap-to-filling- and gap-to-cavity-volume ratios for both types of etching techniques comparing to those of the Peak Universal and control groups. Significant differences between the gaps in external and internal parts of the tooth-filling interface were only noted in the control groups. Internal gap formation and development at the tooth-filling interface depend on the material as well as the type of its application.

Volumetric Assessment of Apical Periodontitis Using Cone-Beam Computed Tomography-A Systematic Review.

This systematic review aimed to investigate the scientific literature on volumetric studies concerning the diagnosis and treatment of apical periodontitis using CBCT. A systematic review protocol was written following the preferred reporting items for the systematic reviews and meta-analyses (PRISMA) checklist. Four electronic databases were searched for relevant publications in English, which were published up to 21 January 2023. The inclusion criteria and corresponding search keys were applied. The risk of bias was assessed using the Joanna Briggs Institute Meta-Analysis of Statistic Assessment and Review Instrument. The search strategy identified 202 studies, with 123 studies excluded during the title and abstract screening and 47 studies left for full text screening. A total of 17 studies met the inclusion criteria. The lesion volume was measured and classified according to different indices which compared the effectiveness of their diagnostics. Moreover, the volume of AP lesions increased with the thickness of the maxillary sinus mucosa in primary and secondary infections and decreased due to endodontic treatment. Volumetric measurements using CBCT are useful in the correct definition of periapical tissue pathosis using a CBCT periapical volume index and assessment of the dynamics of the treatment of apical lesions.

Effectiveness of Teeth Whitening after Regenerative Endodontics Procedures: An In Vitro Study.

Discolouration resulting from regenerative endodontic procedures may have a negative impact on the quality of life of treated patients; therefore, it is recommended to minimize this risk by selecting appropriate scaffolds and barrier materials, and if discolouration occurs, the use of a simple, cost-effective and minimally invasive technique, such as whitening, should be considered. This in vitro study aimed to evaluate tooth discolouration after two- and single-visit regenerative endodontic procedures and the effectiveness of subsequent whitening procedures with carbamide peroxide. Two hundred bovine incisors were included in this study and divided into twenty groups based on the tested material combinations. Two groups were control groups, one with saline and the other group with blood. In the 12 groups, the experiment was designed to be consistent with the two-visit regenerative endodontic procedures. Triple antibiotic paste or calcium hydroxide were placed in the root canal, and then scaffolds (e.g., blood or platelet-rich fibrin) and barrier materials (Biodentine, OrthoMTA or MTA Repair HP) were applied after rinsing the disinfectant pastes. In the six groups that corresponded to the single-visit regenerative endodontic procedure, the use of a disinfectant paste was omitted. Subsequently, the specimens were bleached twice with carbamide peroxide at a 7-day interval. Colour change measurements were performed using a spectrophotometer (VITA Easyshade Compact 5.0, VITA Zahnfabrik, Bad Säckingen, Germany). Statistical analysis was performed with the Kruskal−Wallis H test, the independent t-test and t-test for related samples. Tooth discolouration was noticed after two- and single-visit regenerative endodontic procedures, except for the platelet-rich fibrin+MTA Repair HP group. After the first and second whitening procedures, all of the tested two- and single-visit regenerative endodontic procedures groups showed a change in the colour of the crown, which was noticeable to the naked eye (∆E > 3.3). When analysing the ∆E value between the first and second bleaching procedures, no changes in the colour of teeth were visually noticed in the calcium hydroxide and platelet-rich fibrin +MTA Repair HP groups (∆E < 3.3). Single-visit regenerative endodontic procedures are suggested if possible; however, if two-visit regenerative endodontic procedures are performed, it is recommended to use calcium hydroxide as the disinfectant paste because of the lower staining potential. In the context of discolouration, platelet-rich fibrin is advisable for use as a scaffold. The whitening procedure is worth considering, but does not guarantee a return to the original tooth colour, especially when triple antibiotic paste is used.

The Influence of New Bioactive Materials on Pulp-Dentin Complex Regeneration in the Assessment of Cone Bone Computed Tomography (CBCT) and Computed Micro-Tomography (Micro-CT) from a Present and Future Perspective-A Systematic Review.

The present paper is the first article providing a systematic literature review on the visualization of tertiary dentin influenced by modern bioactive materials in CBCT and micro-CT. Six database searches of studies on tertiary dentin visualization using CBCT produced 622 records in total, and the search of the studies on tertiary dentin using micro-CT produced 502 records in total. The results were thoroughly selected considering the inclusion criteria, and five research papers using CBCT and nine research papers using micro-CT for visualization of tertiary dentin were eventually qualified for the analysis. All the non-randomized and randomized studies presented good and high levels of quality evidence, respectively. Among the bioactive materials used, the most frequently analysed were: MTA, Biodentine dentin matrix hydrogel, Pro Root MTA, and EndoSequence root repair material. The highest thickness of the tertiary dentin was achieved after the use of MTA material in both imaging techniques. The remaining parameters had different results, taking into account the CBCT and micro-CT analysis. The possibilities of the qualitative and quantitative assessment of the particular parameters of tertiary dentin using CBCT and micro-CT techniques were presented and analysed. CBCT and micro-CT analyses can be useful in the assessment of tertiary dentin formed beneath the bioactive material applied during vital pulp treatment. The research argues that the presented results differ depending on the material applied to the pulp, the study duration (4-6 weeks), difference in teeth, species (rats, human), as well as the applied technique and differences in computer software used for the analysis.

Cytotoxic Potential of Denture Adhesives on Human Fibroblasts-In Vitro Study.

(1) In recent years, there has been a significant increase in the availability of denture adhesives for stabilizing removable dentures. The aim of the present study was to assess the cytotoxicity of three denture adhesives on human fibroblasts. (2) Methods: Three denture adhesives were analyzed. Fibroblast cultures were established for the study and control groups in order to assess the incidence of necrosis and to evaluate the microscopic intracellular alterations induced. Following incubation with (study groups) or without adhesives (control group), trypan blue dye exclusion assay was used to determine the number of viable and/or dead cells. Microscopic specimens were stained with haematoxylin and eosin, scanned, digitally processed and then analyzed by a histopathologist. (3) Results: All three denture adhesives analyzed demonstrated various toxic effects in vitro on human fibroblast: quantitative evaluation-45.87-61.13% reduction of cell viability (p = 0.0001) and slight to moderate cytotoxicity in qualitative evaluation. (4) Conclusions: Denture adhesive creams demonstrated a toxic effect on human fibroblasts in vitro in quantitative and qualitative evaluation. In vivo observations are needed to find out if denture adhesives present a cytotoxic effect in patients.

Vital Pulp Therapy in Aesthetic Zone-Identifying the Biomaterial That Reduces the Risk of Tooth Discolouration.

Calcium silicate-based cements are biocompatible materials for vital pulp therapy. However, they discolour the tooth tissue, which is important for the aesthetics of the anterior teeth. The aim of this study was to investigate the effect of calcium silicate-based cements on tooth discolouration. The study included 70 extracted bovine incisors. The crown of the tooth was cut off from the root, 2 mm below the cement-enamel junction. The pulp tissue was removed via a cervical cut with a barbed broach. The teeth were randomly divided into five experimental, one positive, and one negative control groups. The evaluated materials included Biodentine, Ortho MTA, Retro MTA, MTA Plus, MTA Repair HP, and in the positive group, ProRoot MTA. A VITA Easyshade Compact 5.0 spectrophotometer was used before the application, after 1 week, 1 month, 3 months, and 6 months. The significance levels were set at p < 0.05. All materials significantly changed the teeth colour (p < 0.05). However, Ortho MTA, ProRoot MTA, MTA Plus, and Biodentine (ΔE > 6) caused maximum colour change after 6 months. While the ProRoot MTA, Ortho MTA, and MTA Plus caused grey discolouration, Biodentine darkened the shade of the base colour. Thus, Retro MTA and MTA Repair HP can be safely used in the aesthetic dentition zone. According to these clinical results, the possibility of using Biodentine, due to its lack of gray discoloration, can be considered.

New Bioactive Calcium Silicate Cement Mineral Trioxide Aggregate Repair High Plasticity (MTA HP)-A Systematic Review.

Bioactive calcium silicate cement Mineral Trioxide Aggregate (MTA) has been used for years as a gold standard in intravital pulp treatment and specialist endodontic procedures. Owing to flaws of the material, the manufacturers have been trying to enhance and produce materials showing improved physical, chemical and biological parameters. One of the new calcium-silicate cements based on mineral trioxide aggregate, however without some flaws exhibited by the cement, is Mineral Trioxide Aggregate Repair High Plasticity (MTA HP). The aim of the present paper was a systematic literature review concerning the MTA HP material used nowadays in dentistry, as a review of its specific features. The present paper is the first article providing a systematic literature review on MTA HP. The aim of the present article is the better understanding of MTA HP properties, which can aid the decision-making process in endodontic treatment.

Efficiency of Teeth Bleaching after Regenerative Endodontic Treatment: A Systematic Review.

The aim of this review is to evaluate of effectiveness of bleaching procedures used to treat discolored teeth subsequent to regenerative endodontic procedures (REPs) based on the review of in vitro and in vivo studies. This literature review was carried out according to the PRISMA guidelines. Four databases (PubMed, Scopus, the Cochrane Library, and Web of Science databases) were searched electronically, until 30 January 2020 without a year limit. The quality of studies was assessed using a modified methodological index for non-randomized studies. After analyzing 1405 studies, 6 in vitro and 9 in vivo studies were eligible for this review. In in vitro studies, effectiveness of bleaching was assessed in teeth discolored by antibiotic pastes, blood, and barrier materials in various combinations. In all analyzed studies, bleaching was effective in teeth discolored by antibiotic pastes as well as by blood and barrier materials. Of 26 treated teeth in the in vivo studies, 17 teeth were bleached successfully. In six cases, there was improvement of the shade. In three cases, bleaching was not sufficient. Bleaching material, techniques, and times differed between studies. Whitening of discolored teeth after REPs is achievable. However, to establish precise guidelines, further long-term clinical studies should be performed.

The influence of age, sex, and tooth type on the anatomical relationship between tooth roots and the mandibular canal.

PURPOSE: Cone-beam computed tomography (CBCT) reconstructions were analysed to elucidate factors affecting the anatomical relationship between tooth roots and the mandibular canal(MC). MATERIALS AND METHODS: Images of 300 volumetric tomography scans of patients aged between 20 and 79 years old (167 women and 133 men) were analysed. The mean distances between 2,053 dental root apices and the internal border of the MC were obtained by measuring the horizontal and vertical distances on coronal CBCT images. The actual distance was then calculated mathematically with the Pythagorean formula. The statistical significance of differences between men and women was assessed using the Mann-Whitney test. Correlations with patient age were evaluated with the Spearman rank correlation coefficient. RESULTS: The mean distances ranged from 2.17 mm, for single right third molar roots in women, to 8.02 mm for single left third molar mesiolingual roots in men. The mean distances measured for the mandibular right second molar mesial roots and the right second premolar roots were larger in men than in women. Age showed a significant positive correlation with the measured distances for mesial and distal roots of the first and second molar on both sides and the right third molar, mesiolingual roots of the left third molar, and single roots of the right third molar. CONCLUSION: The root-to-mandibular canal distance depended on age and the type of tooth. In 2 root types, this distance was impacted by sex.

In Vitro Infrared Thermographic Assessment of Temperature Change in the Pulp Chamber during Provisionalization: Effect of Remaining Dentin Thickness.

Interim crowns and partial fixed dental prosthesis materials generate exothermic heat during polymerization. The amount of heat transmitted to the pulp chamber can be a function of several factors, including the thickness and quality of the remaining dentin after crown preparation. The aim of this in vitro study was to measure with infrared thermography the temperature changes on the adjacent surface of the chamber roof of premolar teeth extracted from young and old patients (having different thicknesses of remaining dentin after crown preparation) during fabrication of provisional resinous restorations. Twenty extracted human first and second maxillary premolar teeth (10 from young patients, with a relatively large pulp chamber, and 10 from older patients, with a relatively small pulp chamber) were used. The roots were sectioned to expose the inner side of the chamber roof, and the crowns were provisionalized after preparation for a metal-ceramic crown. Two provisional materials, Turbo Temp 2 and Luxatemp Fluorescence, were used. Temperature changes on the inner side of the chamber roof were measured at 2-second intervals using an infrared thermal imaging camera. After completion of the temperature recordings, the teeth were sectioned and the remaining dentin thickness was determined. The older group (mean thickness: 2.82 mm) and younger group (mean thickness: 1.9 mm) differed significantly in dentin thickness (P < 0.014). The mean greatest temperature increases recorded on the chamber roof of teeth with less remaining dentin were 4.07°C for Turbo Temp 2 and 3.94°C for Luxatemp Fluorescence, while increases in the premolars with greater dentin thickness were 1.69°C for Turbo Temp 2 and 1.64°C for Luxatemp Fluorescence. Significant interactions were found between tooth groups (P < 0.000001for Turbo Temp 2 and for Luxatemp Fluorescence). No significant differences were found between assessed materials regardless of the thickness of the remaining dentin (P > 0.38for the older group and P > 0.29 for the younger group). Dentin had a significant effect in limiting the temperature increase generated during polymerization of provisional materials, indicating good thermal insulating properties of this tissue. A remaining dentin thickness of 1.9 mm or more is sufficient to protect the pulp from any temperature increase during provisionalization using tested materials.

Root Surface Temperature Increases during Root Canal Filling In Vitro with Nd:YAG Laser-Softened Gutta-Percha.

The aim of this in vitro study was to measure the temperature increases produced on the mesial and vestibular root surfaces of premolar teeth during a laser-softened gutta-percha obturation technique. We studied 12 extracted human premolar teeth with a single canal. After root canal cleaning and shaping, the teeth were obturated with gutta-percha that had been softened with a neodymium-doped yttrium aluminium garnet (Nd:YAG) laser (CTL 1503) at a wavelength of 1.064 nm. The laser setup parameters included a 30 Hz frequency and a 200 mJ/pulse with optical fiber tips of 0.320 mm diameter. A sectional warm gutta-percha condensation was used. Temperature changes on the whole mesial and vestibular outer surfaces of the roots were measured at approximately 2 s intervals with an infrared thermal imaging camera. A significantly higher increase in temperature was observed for the mesial root surface (7.5°C) compared to the vestibular surface (3.7°C) (p ≈ 0). The findings suggested that root canal filling with Nd:YAG laser-softened gutta-percha in premolar teeth is not likely to damage the surrounding periradicular tissues. To obtain valid temperature results, the measurement should be performed on the surface with the thinnest root wall.

Analysis of the Activity and Expression of Cyclooxygenases COX1 and COX2 in THP-1 Monocytes and Macrophages Cultured with BiodentineTM Silicate Cement.

BiodentineTM is a material based on hydrated calcium silicate with odontotropic properties. However, from the clinician's perspective, every material used to fill a tooth-even those showing the optimal biochemical parameters-is in fact a foreign body introduced to the organism of the host. Therefore, apart from the chemical parameters of such materials, equally important is the so-called biocompatibility of such materials. The aim of the study was to investigate whether BiodentineTM, used in the regeneration of the pulp-dentine complex, may affect the expression of the enzymes cyclooxygenase 1 (COX1) and cyclooxygenase 2 (COX2) in THP-1 monocytes/macrophages and the amount of prostanoids synthesized by these enzymes-precursors of biologically active prostanoids such as prostaglandin E2 (PGE2) and thromboxane (TXB2) which are mediators of inflammation. An original aspect of this research is the use of the THP-1 monocyte/macrophage cell model and the use of biomaterial in direct contact with cells. In this way we tried to reflect the clinical conditions of regenerative pulp and periodontal tissue treatment using BiodentineTM. The results of our study showed a lack of macrophage activation (measured by flow cytometry) and a lack of stimulation of the expression of the studied cyclooxygenase enzymes (measured by Western blotting and fluorescent microscopy), as well as a lack of increase in the concentration (measured by ELISA method) of their inflammatory mediators (PGE2 and TXB2) in vitro incubated with BiodentineTM.

Marginal integrity of flowable and packable bulk fill materials used for class II restorations -A systematic review and meta-analysis of in vitro studies.

This systematic review evaluates the marginal integrity of flowable and packable bulk fill composite materials placed in class II cavities. Electronic databases inclusive of MEDLINE, Scopus, and Web of Science were searched without restriction to date. The titles and abstracts of publications gathered from database searches were screened by reviewers according to the inclusion and exclusion criteria. From as initial yield of 142 articles ten studies were subject to qualitative analysis. The authors emphasized that marginal integrity in enamel and dentin does not significantly differ between flowable and packable bulk fill composites used for class II restorations. Moreover, their marginal integrity was comparable to conventional resin composites with incremental techniques. The adhesive system used with a total etch technique and assessed margin located in enamel resulted in better marginal integrity.

The anatomical relationship between the roots of erupted permanent teeth and the mandibular canal: a systematic review.

PURPOSE: This study reviewed the literature on the position of the mandibular canal (MC) relative to the root apices (RA) of neighbouring teeth using cone beam computed tomography (CBCT). METHODS: The authors searched the PubMed, Scopus, EBSCO Dentistry and Oral Sciences Source, Cochrane and Lilacs databases for relevant English-language articles with no year limitations published through January 25, 2018. RESULTS: The search identified 888 articles, 12 of which met the inclusion criteria. Three groups were found based on the measuring method: the shortest distance from the RA to the MC, the vertical distance from the RA to the MC, or the distance from the RA to the superior cortical bone of the MC. In the first and second groups, the shortest distances to the canines, first premolars, second premolars, first molars, second molars, and third molars were 3.8 mm, 4.76 mm, 1.65 mm, 1.23 mm, 0.64 mm, and 1.28 mm, respectively. In the third group, the shortest distances to the second premolars, first molars, and second molars were 2.71 mm, 3.82 mm, and 1.4 mm, respectively. CONCLUSIONS: The distance from the MC to the RA was generally shorter in females and younger people, with decreasing distances in patients over 60 years old, and depended on the tooth type. TRIAL REGISTRATION: The protocol for this systematic review was registered on PROSPERO (CRD42018085478).

Multidisciplinary Management of a Double Immature Permanent Tooth: A Case Report.

Fused or geminated teeth require complex and multi-faceted treatment to maintain their health, functionality, and appearance. The current paper describes the multidisciplinary/minimally invasive treatment of fused immature permanent teeth. A 9-year-old-girl with an abnormally large left permanent maxillary lateral incisor was referred to the Paediatric Outpatient Clinic. The treatment plan of the referring orthodontist included the extraction of left maxillary lateral incisor, which was fused to a supernumerary tooth, followed by subsequent orthodontic and prosthetic treatments. In the paraclinic evaluation, cone-beam computed tomography (CBCT) showed two separate roots and two root canals, with communication between the pulp chambers of the double teeth. The modified treatment plan was to section the geminated tooth, remove the supernumerary and save the lateral incisor. During the sectioning procedure, the pulp of the remaining tooth was inevitably exposed. Direct pulp capping with Biodentine™ was performed. Next, glass-ionomer cement was applied as a temporary restoration and the supernumerary tooth was removed. The distal surface of the tooth was restored two weeks later so as to re-establish the original shape of the lateral incisor. Clinical and radiographic control examinations revealed that the tooth was symptom-free. Follow-up appointments after 3, 6, 12 and 18 months included standard clinical examinations and sensivity tests including electric pulp testing, which showed a fully functional, healthy tooth with apical maturation. Careful clinical and radiographic evaluations/examinations are essential for determining the correct treatment of a double tooth. The proposed multidisciplinary and minimally invasive treatment of the double tooth using a bioactive cement may facilitate the maturation of immature teeth and result in a desirable aesthetics and function.

Pulp sensibility to electric stimuli in the Caucasian population.

The aim of the study was to determine electric sensibility of the pulp in the Caucasian population depending on tooth morphotype, age and sex. Dental pulp sensibility was determined in 279 patients (2640 teeth). The study group consisted of 226 patients (1296 teeth), 110 men and 116 women aged 55-101. The control group consisted of 53 patients (1344 teeth), 23 men and 30 women aged 20-30. A statistically significant lower sensory threshold and increased pulp sensibility in the study group were noted. These affected the lower incisors, the second upper premolars and the first and second upper molar. The differences in the pulp sensibility were found in the region of maxillary central incisors, maxillary premolars, mandibular lateral incisors and mandibular premolars. The pulp sensibility threshold was lower for the aforementioned groups of teeth in the study group. The correlation between sensibility of the pulp and sex was not confirmed.

Evaluation of gap formation at the composite resin-tooth interface after using universal adhesives: In vitro SEM study using the replica technique.

The aim of this study was to evaluate gap formation after using two universal adhesives, Peak Universal Bond (P), which contains chlorhexidine and Adhese Universal (A), which contains 10-MDP monomer, and to compare them with two gold standard adhesives. The adhesives were tested in different etching modes, etch-and-rinse (ER) or self-etch (SE), and under thermomechanical loading (TML). Two identical Class V cavities were prepared in each of 30 human third molar teeth, and resin-composite restorations were made. Before and after TML, replicas of the restorations were prepared. Gap formation and their frequency according to the modified classification of Blunck and Zaslansky and the width of the maximum marginal gap (MG) were separately evaluated in enamel and dentin. Gap frequency did not differ significantly only in the enamel before TML, despite the use of different adhesives or etching modes. At both timepoints, the highest MG values were obtained with the Peak Universal Bond self-etch (PSE) group in enamel (6.2 µm before TML, 12.2 µm after TML) and the Peak Universal Bond etch-and-rinse (PER) group in dentine (21.3 µm before TML, 35.5 µm after TML). After TML, there was a significant increase of gap frequency for Adhese universal self-etch (ASE) group and MG values for PER, PSE, ASE groups at the resin-enamel interface, and gap frequency and MG values for all groups at the resin-dentin interface. Universal adhesive with 10-MDP monomer have beneficial effect on the resin-dentin interface, while chlorhexidine may reduce the resistance of the universal adhesive system to oral cavity conditions.

Materials used in regenerative endodontic procedures and their impact on tooth discoloration.

There is some evidence of tooth discoloration after regenerative endodontic procedures. The aim of this review is to determine which materials used in regenerative procedures induce tooth discoloration. The authors searched six digital databases in February 2018: PubMed, Google Scholar, the Cochrane Library, Scopus, Web of Science, and Lilacs. As a result, 353 studies were found. Eleven studies that met the established criteria were selected. Analysis of the selected studies showed that most materials used in regenerative endodontic procedures have the potential to stain tooth tissues. To decrease tooth discoloration, sealing dentin with a dentin-bonding agent before the placement of a disinfectant paste and barrier materials should be considered. Only a small number of in vitro studies have been performed; therefore, further studies on this topic are warranted.

SEM and EDS study of TotalFill BC Sealer and GuttaFlow Bioseal root canal sealers.

BACKGROUND: Recently, a new generation of calcium silicate-based root canal sealers has been developed. These new types of sealers have the ability to set in wet environment, have high alkalinity and present potential antimicrobial activity. OBJECTIVES: The aim of this study was to determine the chemical composition and microstructure of 2 novel calcium silicate-containing root canal sealers - TotalFill® BC Sealer and GuttaFlow® Bioseal. MATERIAL AND METHODS: The tested sealers were prepared according to the manufacturers' instructions. Sixteen cylindrical dishes (inner diameter: 4 mm; height: 3 mm) were placed on a glass Petri dish and packed with the materials. The Petri dish was transferred to an incubator. After the sealers set, excess material was removed with diamond discs and polishing paste. The materials were assessed using scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) X­ray microanalysis. RESULTS: Both TotalFill BC Sealer and GuttaFlow Bioseal contained calcium, zirconium, oxygen, carbon, silicon, and a trace of sodium. In the case of TotalFill BC Sealer, trace amounts of copper and technetium were also present, and for GuttaFlow Bioseal, iron, zinc, and a trace of magnesium and hafnium were noted. No bismuth was found. Both of the assessed sealers contained fine particles embedded in the matrix; however, GuttaFlow Bioseal also had larger particles with a diameter of 2-10 µm. CONCLUSIONS: TotalFill BC Sealer represents a higher degree of purity in comparison with GuttaFlow Bioseal. The clinical implications of heavy metals present in GuttaFlow Bioseal need to be investigated. Both materials have a fine particle structure, which is desirable for root canal sealers.

Histological evaluation of hard tissue formation after direct pulp capping with a fast-setting mineral trioxide aggregate (RetroMTA) in humans.

OBJECTIVES: To histologically evaluate the morphology of the newly formed mineralized tissue and of the adjacent cells, in intact human teeth subjected to mechanical pulp exposure and capping with a fast-setting mineral trioxide aggregate (RetroMTA). MATERIALS AND METHODS: Seven caries-free third molars from three adults were subjected to pulp exposure, direct capping with RetroMTA, and restoration with a composite resin. Seven months later, the teeth were clinically and radiographically evaluated, extracted, and subjected to histological processing and evaluation. RESULTS: All teeth were clinically and radiographically inconspicuous and showed no presence of severe inflammatory reactions. Bacteria were absent in all teeth. All cases exhibited some degree of mineralized tissue in the area of exposure to varying extent. This newly formed mineralized tissue was mostly atubular and did not display the features of regular dentine in any of the cases. No cells exhibiting the features of odontoblasts or odontoblast-like cells were observed. Instead, the cells exhibited a flat or cuboidal shape, resembling fibroblasts. CONCLUSIONS: When the exposed pulps were directly capped with RetroMTA, the new calcified hard tissue was not "regular dentine," and did not seem to be the product of genuine odontoblast differentiation. These results suggest that the formation of calcified tissues after direct pulp capping with RetroMTA may be more appropriately regarded as a reparative process than as a genuine regeneration response. CLINICAL RELEVANCE: This is the first histological study on humans showing that regular dentine was not regenerated when a bioactive pulp-capping material (RetroMTA) was placed over exposed pulp tissue. TRIAL REGISTRATION: NCT03631511.