The Microbiota Profile Analysis of Combined Periodontal-Endodontic Lesions Using 16S rRNA Next-Generation Sequencing.

OBJECTIVE: The primary aim of this investigation was to analyze the microbiome in patients with combined periodontal-endodontic lesions. METHOD: Patients with loose and/or painful teeth referred for treatment from March 2020 to December 2020 in the First People's Hospital of Jinzhong were recruited. Samples were collected from teeth diagnosed as chronic periodontics (PE), ulcerative pulpitis (PU), and retrograde pulpitis (RE). Genomic DNA was extracted. The quantitative polymerase chain reaction, targeting the 16S ribosomal RNA (rRNA), was adopted for the quantification of bacteria. Then, the V3-V4 hypervariable regions of the 16S rRNA gene were amplified and subjected to next-generation sequencing. The statistical analysis was performed by R software (V3.5.1). RESULTS: A total of 57 qualified samples were collected from 48 patients and analyzed (7 PE, 21 PU, and 19 RE). By linear discriminant analysis effect size, Kingella and Barnesiella were significantly increased in the periodontal pocket of retrograde pulpitis (RE-PE), compared with PE. The relative abundance of Clostridiales Incertae Sedis XI, Fusobacteriaceae, Fusobacterium, Parvimonas, Micrococcaceae, and Rothia was significantly increased in the pulp of retrograde pulpitis (RE-PU) than PU and RE-PE. Prevotella, Leptotrichia, Porphyromonas, Streptococcus, and Fusobacterium are consistently at a high abundance, across PU, RE-PE, and RE-PU. CONCLUSION: The current study highlighted the evidence that a specific microbial community is associated with the occurrence of retrograde pulpitis. The microenvironment of the root canal and pulp chamber will select microbiota. This study offered insights into the pathogenesis of retrograde pulpitis.

Endodontic length measurements using cone beam computed tomography with dedicated or conventional software at different voxel sizes.

The aim of this study is to investigate the accuracies and the agreements of the 3D Endo software, conventional CBCT software Romexis Viewer at three voxel sizes, and the EAL ProPex Pixi in endodontic length measurements. Three hundred and twenty-nine root canals in 120 intact human extracted molars were accessed. The actual lengths (AL) and electronic lengths (EL) were measured using the ruler and electronic apex locator (EAL), respectively. Teeth were scanned using the CBCT at different voxel sizes (0.075, 0.10, and 0.15 mm). Root canal lengths were measured using 3D Endo with proposed length (3D-PL) by software, corrected length (3D-CL), Romexis Viewer. The Fisher's exact test, paired t-test and Bland-Altman plots were calculated to detect the agreements of the four methods with AL measurements. The ProPex Pixi measurements obtained the highest accuracy in the range of ± 0.5 mm. There was agreement between the 3D-PL and the 3D-CL with AL measurements at voxel size of 0.15 mm and at voxel size of 0.10 mm, respectively. The CBCT Romexis Viewer measurements agreed with AL at three voxel sizes. The conventional CBCT measurements using Romexis Viewer and dedicated software did not reach to the 100% accuracy in the range of ± 0.5 mm.

Clinical, Radiographic, and Histologic Outcome of Regenerative Endodontic Treatment in Human Teeth Using a Novel Collagen-hydroxyapatite Scaffold.

INTRODUCTION: Histologic examination of teeth after regenerative endodontic treatment (RET) shows that the type, quality, and quantity of tissues formed in the root canal space are not predictable. The aim of this study was to examine clinically, radiographically, and histologically the outcome of RET in immature noninfected human teeth using SynOss Putty (Collagen Matrix Inc, Oakland, NJ) as a scaffold. METHODS: Three pairs of maxillary/mandibular first premolars in 3 patients scheduled for extraction were included. Sensibility tests confirmed the presence of vital pulps. After informed consent, anesthesia, and rubber dam isolation, the pulps were removed. RET was performed using the following scaffolds: SynOss Putty + blood in both teeth in patient #1, SynOss Putty with or without blood in patient #2, and SynOss Putty + blood or blood only in patient #3. After a follow-up period of 2.5-7.5 months, the teeth were clinically and radiographically evaluated, extracted, and examined histologically. RESULTS: Patients remained asymptomatic after treatment. Radiographic examination of the teeth showed signs of root development after treatment. In teeth treated with SynOss Putty + blood, histologic examination showed formation of intracanal mineralized tissue around the scaffold particles solidifying with newly formed cementumlike tissue on the dentinal walls. The tooth treated with SynOss Putty without blood showed the formation of a periapical lesion. The tooth treated with a blood clot only showed tissues of periodontal origin growing into the root canal space. CONCLUSIONS: SynOss Putty + blood showed a predictable pattern of tissue formation and mineralization when used as a scaffold for RET in human immature noninfected teeth. The newly formed mineralized tissue solidifies with newly formed cementum on the dentinal walls.

The Effect of Heating to Intracanal Temperature on the Stability of Sodium Hypochlorite Admixed with Etidronate or EDTA for Continuous Chelation.

INTRODUCTION: Tetrasodium etidronate (Na4 etidronate) and tetrasodium EDTA (Na4 EDTA) are chelators that can combine with sodium hypochlorite (NaOCl) as a 1-mix endodontic irrigant in a process called continuous chelation. The therapeutic window of these mixtures is determined by the chemical reaction between NaOCl and the chelator. At room temperature, this window is 60 minutes for Na4 etidronate and 30 minutes for Na4 EDTA. Because reaction kinetics are influenced by heat, this study assesses the influence of heating to an intracanal temperature of 35°C on the therapeutic window in continuous chelation. METHODS: The loss of free available chlorine (FAC) in NaOCl mixtures with Na4 etidronate or Na4EDTA was determined by iodometric titration at 23°C ± 0.7°C (23°C) and 34.6°C ± 0.3°C (35°C) at 1, 20, 40, and 60 minutes after mixing. The pH and temperature of the mixtures were measured. RESULTS: At 23°C, 18% Na4 etidronate/5% NaOCl solutions at 20, 40, and 60 minutes lost 4%, 9% and 18% FAC, and at 35°C, they lost 20%, 68% and 92% FAC; 5% Na4 EDTA/2.5% NaOCl solutions at 20, 40, and 60 minutes at 23°C lost 88%, 94%, and 97% FAC, and at 35°C, they lost 96%, 99%, and 100%. Decreases in FAC were accompanied by pH declines. CONCLUSIONS: The effect of heating to 35°C from a room temperature of 23°C on 18% Na4 etidronate/5% NaOCl solutions reduces its therapeutic window to 20 minutes. Solutions of 5% Na4 EDTA/2.5% NaOCl are not useful in the continuous chelation technique. Tracking pH changes could be used to estimate NaOCl degradation.

Characterization of the apical bridge barrier formed following amelogenin apexification.

BACKGROUND: Recombinant amelogenin protein (RAP) is reported to induce complete root apex formation in dog model when used as apexification therapy. It also induces pulp regeneration in 85% of the treated group. Thus, the aim of this study was to investigate the nature of the remaining regenerated calcified tissues of the RAP group that showed no pulp regeneration compared to the calcium hydroxide treated group (CH). METHODS: A total of 240 dogs' open apex root canals were used, after establishment of canals contamination. Canals were cleaned, irrigated, and filled with RAP as an apexification material and compared with CH. Treated teeth were assessed by H&E, trichrome staining, and/or immunohistochemistry technique, at 1, 3, and 6 months. RESULTS: A time-dependent increase in the calcified tissue barrier was observed in the apex of the RAP-treated group compared to the CH-treated group. The newly formed dentin in this RAP group was mainly tubular dentin and was functionally attached to the bone by periodontal ligament, while the CH group showed dentin-associated mineralized tissue (DAMT) associated with the newly formed apical barrier. CONCLUSIONS: Out results suggest that RAP can be used as novel apexification material, resulting in a thickening and strengthening of the canal walls, and achieving apical closure.

Real-time Intracanal Temperature Measurement During Different Obturation Techniques.

INTRODUCTION: The purpose of this study was to assess temperature development in endodontic sealers during different obturation techniques in a closed system simulating the surrounding biological structures at body temperature. METHODS: The root canals of 48 human single-rooted maxillary canines were instrumented with ProTaper Gold (Dentsply Sirona, York, PA) to size F3. On the buccal aspect of each root, artificial side canals with a diameter of 0.5 mm were drilled at a distance of 3, 6, and 9 mm from the apical foramen, and type K thermocouples were inserted via plastic pipes. The roots were positioned in plastic vials filled with alginate. The root canals were obturated by the continuous wave and warm backfill technique, Thermafil obturators (Dentsply Sirona), or single-cone obturation (n = 12) at body temperature using AH Plus sealer (Dentsply Sirona). Temperature measurement during the obturation procedure was assessed by thermocouples. Statistical analysis of the maximum temperature change was performed using the Kruskal-Wallis test (P = .05). RESULTS: The continuous wave and warm backfill technique caused significantly higher temperatures than Thermafil and single-cone obturation (P < .05). The continuous wave technique revealed significantly higher temperatures than the warm backfill technique at 3 mm and 6 mm from the apex (P < .05). CONCLUSIONS: In a closed system with simulated surrounding tissues at 37°C, the continuous wave technique produced higher increases in temperature than the warm backfill technique with a maximum of 19.1°C. The temperature increase during Thermafil obturation was negligible. The temperature increase in the endodontic sealer was markedly lower than expected from root surface temperature measurement studies.

Reacción pulpar frente a fuerzas ortodónticas: evaluación de la primera semana de tratamiento / Pulpal response to orthodontic forces: evaluation of the first week of treatment

Objetivos: Evaluar la correlación entre: (I) los niveles de fuerza aplicados a dientes anteriores en las etapas iniciales del tratamiento ortodóntico; (II) la percepción de dolor y (III) la sensibilidad pulpar. Universo y Muestra: Clínica de Especialización en Ortodoncia y Ortopedia MáxiloFacial de la Universidad San Sebastián en Santiago de Chile durante los años 2012 al 2014. Se obtuvo una muestra no probabilística por conveniencia de 136 dientes en 37 pacientes con brackets y Arcos de (TM)Nitinol termoactivados (35ºC) de 0.014 pulgadas. Material y Método: Estudio observacional prospectivo. Los dientes fueron evaluados con un dinamómetro siendo las fuerzas clasificadas en cuatro categorías: leves, óptimas, altas y extremas. El dolor fue medido con la Escala Visual Análoga al primer, segundo y séptimo día, después del comienzo de la aplicación de la fuerza y al séptimo día también se sometieron los dientes a test térmicos. Resultados: Después de unas horas del comienzo de la aplicación de la fuerza, el dolor comenzó a disminuir. Con el aumento de magnitud de las fuerzas, el dolor no varió en intensidad. El 39.1% de los dientes que recibieron fuerzas "óptimas" y el 22.4% de los que recibieron fuerzas "extremas", mostraron una respuesta aumentada al frío. El 1% de los dientes sometidos a fuerzas "extremas" presentó una respuesta aumentada al calor. Conclusiones: En los primeros siete días, no se observó daño pulpar irreversible independiente de la magnitud de la fuerza aplicada

Objectives: To evaluate the correlation between: (I) force levels applied to anterior teeth in the initial stages of orthodontic treatment; (II) pain perception, and (III) pulp sensitivity. Setting and Sample Population: Orthodontics and Maxillofacial Orthopedics Clinic at San Sebastián University in Santiago, Chile from 2012 to 2014. A non-probabilistic convenience sample was obtained of 136 teeth in 37 patients with braces and 0.014-inch heat-activated (35ºC) Nitinol(TM) arch wires. Material and Method: Prospective observational study. Teeth were evaluated with a dynamometer. Forces were classified into four categories: mild, optimal, high, and extreme. Pain was measured with the Visual Analog Scale (VAS) on the first, second, and seventh day after the force application, and thermal tests were applied on the seventh day. Results: A few hours after the beginning of the force application, the pain began to diminish. The pain did not vary in intensity with increasing force magnitude. 39.1% of the teeth which received "optimal" forces and 22.4% of those which received "extreme" forces exhibited an increased response to cold. 1% of the teeth subjected to "extreme" forces exhibited an increased response to heat. Conclusions: In the first seven days, no irreversible pulpal damage was observed regardless of the magnitude of the applied force

Effects of different resin adhesives on the microleakage in a new model with simulated subgingival condition and pulpal pressure.

Resin adhesive restorations are susceptible to oral fluid contamination and greatly influenced by dentinal tubule fluid because of pulpal pressure, especially when the restorative cavities are near gingival tissues. This study designed a novel model to evaluate the microleakage of self-adhesive flowable composite and traditional resin adhesives under simulated subgingival cavity preparations and pulpal pressure. We applied three different adhesive systems, include Vertise Flow, Optibond all-in-one, and Optibond S, on premolars with V-shaped cavity. All samples exhibited good marginal sealing at resin-enamel interfaces. At resin-dentin interfaces, microleakage in control group was similar among different adhesive systems. Microleakage in group pulpal pressure was greater than that in control group for all adhesive systems except Vertise Flow. All adhesive systems in pulpal pressure and simulated subgingival group exhibited significantly greater microleakage. In total, Vertise Flow exhibited better marginal sealing under pulpal pressure than other traditional adhesives.

Tubular dentin sealer penetration after different final irrigation protocols: A confocal laser scanning microscopy study.

The aim of this study was to evaluate tubular dentin sealer penetration, comparing different final irrigation protocols using a conventional needle (CONV), EndoActivator system (EAS), EndoVac system (EVS), and ultrasound (PUI). Initially, fifty-two first maxillary molars with a single canal in the palatal root, without abrupt curvatures, resorptive processes, or previous endodontic treatment were selected for this study. Then, the crowns were sectioned to obtain palatal roots 15 mm in length. The root canals were prepared with the ProTaper Universal System and irrigated with 5% NaOCl. Afterwards, the specimens were divided into four groups (n. 13), according to the final irrigation protocol: CONV, EAS, EVS, and PUI. After filling, slices at 3 mm and 5 mm from the apex were obtained for analysis by confocal laser scanning microscopy. Two-way comparisons between the groups and the levels were performed with Games Howell's test (p < .05). Tubular dentin sealer penetration was higher at 5 mm compared with 3 mm from the apex (p < .05). The EAS group showed a higher percentage of tubular dentin sealer penetration, compared with the CONV group, at both levels. At 3 mm, there was no statistically significant difference among EAS, EVS, and PUI; however, these groups showed better performance, compared with the CONV group. At 5 mm, there was no statistically significant difference between the EAS and EVS groups, but both showed higher sealer penetration than the PUI group (p < .05). The EAS and EVS groups achieved better degrees of tubular dentin sealer penetration, compared with the other groups.

The role of bone morphogenetic proteins 2 and 4 in mouse dentinogenesis.

OBJECTIVE: The bone morphogenetic proteins (BMPs) play crucial roles in tooth development. However, several BMPs retain expression in the dentin of the fully patterned and differentiated tooth. We hypothesized that BMP signaling therefore plays a role in the function of the differentiated odontoblast, the job of which is to lay down and mineralize the dentin matrix. DESIGN: We generated mice deficient in Bmp2 and 4 using a dentin matrix protein 1 (Dmp1) promoter-driven cre recombinase that was expressed in differentiated odontoblasts. RESULTS: The first and second molars of these Bmp2 and Bmp4 double conditional knockout (DcKO) mice displayed reduced dentin and enlarged pulp chambers compared to cre-negative littermate controls. DcKO mouse dentin in first molars was characterized by small, disorganized dentinal fibers, a wider predentin layer, and reduced expression of dentin sialophosphoprotein (DSPP), dentin matrix protein 1 (DMP1), and bone sialoprotein (BSP). DcKO mouse odontoblasts demonstrated increased type I collagen mRNA production, indicating that the loss of BMP signaling altered the rate of collagen gene expression in these cells. Bmp2 and Bmp4 single Dmp1-cre knockout mice displayed no discernable dentin phenotype. CONCLUSIONS: These data demonstrate that BMP signaling in differentiated odontoblasts is necessary for proper dentin production in mature teeth.

Histologic Findings of a Human Immature Revascularized/Regenerated Tooth with Symptomatic Irreversible Pulpitis.

INTRODUCTION: Pulp revascularization/regeneration in immature permanent teeth with necrotic pulp and/or apical periodontitis is an effective approach for inducing root maturation. Previous histologic studies showed cementoid/osteoid tissue and/or periodontal ligament-like tissue formed within the root canals. This case report describes the histologic findings of a human symptomatic irreversible pulpitis immature permanent tooth with most of the pulp removed after a revascularization/regeneration procedure. METHODS: A human immature permanent mandibular premolar (tooth #29) was diagnosed as symptomatic irreversible pulpitis with symptomatic apical periodontitis at the emergency department. Most of the pulp was removed. The tooth was treated with revascularization/regeneration. RESULTS: At the 12-month recall, the radiographic examination revealed thickening of the root canal wall, narrowing of the root apex, and lengthening of the root. The tooth was extracted at 12 months for orthodontic treatment. The specimens were processed for histologic examination. Histologically, the apical third of the root canal was filled with newly formed dentinlike and pulplike tissue. There was a layer of flattened odontoblastlike cells lining the dentinal wall. In the midportion of the root canal, the newly formed dentinlike tissue gradually changed to cementumlike tissue. In the upper third of the root canal, there was a presence of cementocytelike cells housed in the lacunae of cementumlike tissue around the loose connective tissue. CONCLUSIONS: In the present case, regeneration of the pulplike tissue and the periodontium existed after a revascularization/regeneration procedure in an immature permanent tooth clinically diagnosed as symptomatic irreversible pulpitis.

Second-generation Platelet Concentrate (Platelet-rich Fibrin) as a Scaffold in Regenerative Endodontics: A Case Series.

INTRODUCTION: The purpose of this case series was to report the clinical and radiographic results of a pulp regenerative procedure using platelet-rich fibrin (PRF), a second-generation platelet concentrate, in immature teeth with necrotic pulps. METHODS: Root canal revascularization using PRF was performed on 4 immature teeth with necrotic pulps. After access cavity preparation, the root canals were irrigated with low concentration sodium hypochlorite solution (1.5% sodium hypochlorite [20 mL/canal, 5 minutes]) and then irrigated with saline (20 mL/canal, 5 minutes). Equal proportions (167 mg) of ciprofloxacin, metronidazole, and cefaclor were mixed and diluted to a final concentration of 1 g/mL. Finally, the canal was sealed with 3-4 mm of a temporary restorative material, and patients were dismissed for 2 to 3 weeks. At the second appointment, 9 mL of the patient's whole blood was obtained and centrifuged to prepare a PRF clot. Canals were irrigated with 17% EDTA, and a sharp spreader was inserted beyond the apex. Then, the PRF clot was placed inside the root canals, and Biodentine (Septodont, Saint-Maur, France) was placed directly over the PRF. The teeth were restored permanently with glass ionomer cement and composite resin. RESULTS: Clinical examinations revealed that all cases were asymptomatic at the recall appointments at 1, 3, 6, 12, and 18 months. Radiographs revealed resolution of the periapical lesions, further root development, and apical closure in all cases. CONCLUSIONS: On the basis of the short-term results up to 12 months, PRF clots acted as successful scaffolds for the regeneration of pulpal contents in immature teeth with necrotic pulps.

Biological Evaluation of Implant Drill Made from Zirconium Dioxide.

PURPOSE: Zirconia is a good candidate material in the dental field. In this study, we evaluated biological responses against a zirconia drill using a bone cavity healing model. MATERIALS AND METHODS: Zirconia drills, stainless steel drills, and the drilled bone surface were observed by scanning electron microscopy (SEM), before and after cavity preparation. For the bone cavity healing model, the upper first and second molars of Wistar rats were extracted. After 4 weeks, cavities were prepared with zirconia drills on the left side. As a control, a stainless steel drill was used on the right side. At 3, 7, and 14 days after surgery, micro-CT images were taken. Samples were prepared for histological staining. RESULTS: SEM images revealed that zirconia drills maintained sharpness even after 30 drilling procedures. The bone surface was smoother with the zirconia drill. Micro-CT images showed faster and earlier bone healing in the zirconia drill cavity. On H-E staining, at 7 days, the zirconia drill defect had a smaller blank lacunae area. At 14 days, the zirconia drill defect was filled with newly formed bone. CONCLUSIONS: The zirconia drill induces less damage during cavity preparation and is advantageous for bone healing. (197 words).

Influence of Age and Apical Diameter on the Success of Endodontic Regeneration Procedures.

INTRODUCTION: Treatment of immature permanent teeth with necrotic pulp and apical pathosis constitutes a challenge for endodontists. The present study was done to evaluate the effect of age and apical diameter on the regenerative potential of young permanent immature teeth with necrotic pulps. METHODS: Immature necrotic permanent maxillary incisors (n = 40) of patients 9-18 years old were divided into 2 groups according to the treatment protocol: group Y (younger age group), 9-13 years and group O (older age group), 14-18 years. Each group was further subdivided into 2 subgroups according to apical diameter, subgroup (n) (narrower diameter) between 0.5 and 1 mm and subgroup (w) (wider diameter) equal to or greater than 1 mm. Revascularization procedures were performed for all patients. Follow-up was done for up to 12 months. Standardized radiographs were digitally evaluated for increase in root length and thickness and decrease in apical diameter. RESULTS: After the follow-up period, most of the cases demonstrated radiographic evidence of periapical healing. Group Y showed significant progressive increase in root length and width and decrease in apical diameter. Subgroup (w) representing wider apical diameter showed significant progress as well. CONCLUSIONS: It was found that revascularization procedures can be implemented in any age ranging from 9 to 18 years; however, younger age groups were better candidates for revascularization procedure than older ones. Regarding the apical diameter, regeneration procedures were successful with apical diameters as small as 0.5 mm. However, teeth with preoperative wider diameters (≥1 mm) demonstrated greater increase in root thickness, length, and apical narrowing.

Thermotransduction and heat stress in dental structures during orthodontic debonding : Effectiveness of various cooling strategies.

OBJECTIVES: Recent studies have indicated possible thermal damage to pulpal tissue during orthodontic debonding. This study aimed to analyze the thermal loads acting upon dental structures and their transfer to the pulp during orthodontic debonding. Specific goals were to analyze temperature changes in local dental tissues, thermotransduction to the pulp cavity, and the effectiveness of common cooling strategies and of simulated intrapulpal circulation. MATERIALS AND METHODS: Metal brackets were bonded to five extracted human molars and subsequently removed. While a carbide bur was applied to debond the residual composite from the tooth surface, various cooling strategies (no/air/water cooling) were employed with or without simulated intrapulpal circulation, accompanied by temperature measurements with a thermographic infrared camera on the enamel surface and with measuring probes in the pulp cavity. Appropriate evaluation software was used to calculate the enamel-to-pulp temperature gradients and for statistical analysis. RESULTS: Significant differences in temperature rise and heat development over time, both on the enamel surfaces and in the pulp cavities were found. The mean temperature rises associated with no/air/water cooling were 90.7/46.6/9.2 °C on the enamel surface versus 9/8/4.6 °C inside the pulp. However, thermotransduction from enamel to pulp remained below 10 % of the surface measurements in all groups. Simulated intrapulpal microcirculation was found to significantly reduce intrapulpal temperature levels. CONCLUSION: During debonding of residual bracket adhesives, provided that a carbide bur is properly used, our data indicate a low risk of reaching critical intrapulpal temperatures even in the absence of dedicated cooling and no risk if the instrumentation is accompanied by air or water cooling.

Intracanal molar barometric pressure differentials at simulated altitude conditions - proof of concept study.

AIM: To evaluate whether objective data could be obtained regarding internal pressure conditions of a molar tooth with canals prepared but not filled exposed to reduced barometric pressures that could be experienced by aircrew. METHODOLOGY: The root canals of five mandibular molars were prepared but not filled. Root apices were sealed with a resin-modified glass-ionomer liner and root surfaces sealed with a dental adhesive. The sealed root surfaces were then coated with a polyvinylsiloxane (PVS) adhesive and the teeth inserted into cylinders of PVS impression material to the level of the cervical enamel junction. Barometric pressure transducers were placed in the pulp chambers with the endodontic access sealed with cotton and a provisional restoration. The specimens were then subjected to a manually controlled, atmospheric altitude challenge consisting of a slow ascent and descent to a simulated 25 000 feet above sea level followed by a rapid altitude climb and descent. The real-time difference between intracanal and simulated atmospheric pressures were recorded and correlated (Pearson's, P = 0.05). RESULTS: No tooth material fractured, and there was no failure of the provisional restorations. Barometric pressures inside the closed prepared molar canals and the ambient atmospheric pressure were found to correlate (r(2)  = 0.97-0.99; P < 0.0001), but pressure equalization lags were observed. However, no differences greater than six pounds per square inch (310 torr) were noted. CONCLUSION: This pilot study established a protocol that demonstrated that objective data regarding barometric pressures within the prepared canals of molars can be obtained at simulated altitude conditions.

Algunos indicadores bibliométricos referidos a la endodoncia, presentes en revistas médicas cubanas / Bibliometric indicators of endodontics in Cuban medical journals

Introducción: la comunicación científica se realiza a través de la publicación de artículos en revistas especializadas, por este motivo, el estudio cuantificado de las revistas conocido, como bibliometría, constituye un método que permite evaluar el desarrollo científico. Objetivo: determinar las características de la producción científica que trate el tema de endodoncia en las revistas médicas cubanas, hasta el presente. Métodos: se realizó un estudio observacional, descriptivo y transversal. El universo estuvo constituido por 22 116 artículos, y la muestra por todos los artículos relacionados con la endodoncia (25 artículos) publicados por autores cubanos en revistas cubanas de ciencias médicas hasta el año 2014. Se incluyeron todos los artículos sin establecer preferencia por el idiomaLa búsqueda se realizó a través de SciELO, Biblioteca Virtual de Salud, y servicio SCAD. Los descriptores emplearon fueron: endodoncia, tratamiento conducto radicular, terapia(s) pulpar(es) y combinaciones entre ellos. Resultados: de los 25 artículos referidos al tema endodoncia 4 eran de los últimos 5 años. Se halló 3 autores por artículo (32 por ciento). La mayoría de los autores (24 por ciento) pertenecía a la Facultad de Estomatología de La Habana. Entre los artículos, 83,3 por ciento eran originales. Predominan los artículos sobre terapéuticas (40 por ciento). Conclusiones: la producción científica cubana en la temática endodóntica es escasa. La revista que más ha publicado artículos referidos al tema es la Revista Cubana de Estomatología. Las terapéuticas han sido las temáticas más tratados. La institución que más ha aportado al tema es la Facultad de Estomatología de La Habana(AU)

Introduction: scientific communication materializes through the publication of papers in specialized journals. This is the reason why the quantitative study of journals, known as bibliometry, is a method allowing to evaluate scientific development. Objective: determine the characteristics of scientific production about endodontics in Cuban medical journals until the present moment. Methods: a cross-sectional observational descriptive study was conducted. The study universe was composed of 22 116 papers. The study sample was all the papers about endodontics (25 papers) published by Cuban authors in Cuban medical journals until the year 2014. All papers were included irrespective of the language in which they were written. The search was conducted in SciELO, the Virtual Health Library and the SCAD service. The search terms used were endodontics, root canal treatment, pulp therapy(ies) and combinations thereof. Results: of the 25 papers about endodontics, four had been published in the last five years. The number of authors per paper was three (32 percent). Most authors (24 percent) were from the School of Dentistry of Havana. 83.3 percent of the sample were original papers. There was a predominance of papers about therapeutics (40 percent). Conclusions: cuban scientific production on endodontics is scarce. The publication with the largest number of papers on the subject is the Cuban Journal of Dentistry. Therapies are the most common topic. The most productive institution is the School of Dentistry of Havana(AU)

Real-Time Analysis of Temperature Changes in Composite Increments and Pulp Chamber during Photopolymerization.

OBJECTIVE: The aim of this study was to evaluate the temperature change at various sites within the composite and on the pulpal side of dentin during polymerization of two composite increments. MATERIALS AND METHODS: Class I cavities prepared in third molars were restored in two composite increments (n = 5). Temperatures were measured for 110 s using eight thermocouples: bottom center of cavity (BC), top center of 1st increment (MC), top center of 2nd increment (TC), bottom corner of cavity (BE), top corner of 1st increment (ME), top corner of 2nd increment (TE), pulpal side of dentin (PD), and center of curing light guide tip (CL). RESULTS: Maximum temperature values (°C) measured during polymerization of 1st increment were MC (59.8); BC (52.8); ME (51.3); CL (50.7); BE (48.4); and PD (39.8). Maximum temperature values during polymerization of 2nd increment were TC 58.5; TE (52.6); MC (51.7); CL (50.0); ME (48.0); BC (46.7); BE (44.5); and PD (38.8). CONCLUSION: Temperature at the floor of the cavity was significantly higher during polymerization of 1st increment compared to 2nd increment. Temperature rise was higher at the center than at the corner and at the top surface than at the bottom surface of each increment.

Current Applications and Future Prospects of Stem Cells in Dentistry.

Stem cells are defined as clonogenic, unspecialized cells capable of both selt-renewal and multi-lineage differentiation, contributing to regenerating specific tissues. For years, restorative treatments have exploited the lifelong regenerative potential of dental pulp stem cells to give rise to tertiary dentine, which is therapeutically employed for direct and indirect pulp capping. Current applications of stem cells in endodontic research have revealed their potential to continue root development in necrotic immature teeth and transplanted/replanted teeth. Successful application of pulp revascularization is highlighted here with support of a clinical case report. This article also discusses the role of dental stem cells as a promising tool for regeneration of individual tissue types like dentine, pulp and even an entire functional tooth.

Effect of 1-piece post and core fabrication techniques on fracture strength.

PURPOSE: The purpose of this in vitro study was to evaluate and compare the fracture strengths of post and core systems produced with different fabrication techniques and materials. METHODS: Forty extracted human single-root premolars were used in this study. After root canal treatment, the teeth were randomly divided into 4 groups of 10 each as follows: group C: metallic 1-piece posts and cores fabricated by casting, and serving as the control; group CM: metallic posts and cores fabricated with the copy milled technique; group LS: 1-piece posts and cores fabricated with the laser sintering technique; and group ZR: 1-piece zirconia posts and cores fabricated with computer-aided design and computer-aided manufacturing (CAD-CAM). The posts and cores were cemented to the teeth with adhesive resin cement; then, the specimens were mounted to acrylic resin blocks, attached to an Instron Universal Testing Machine, and loaded with a crosshead speed of 1 mm/min, until fracture. Data were statistically analyzed using 1-way analysis of variance (ANOVA), followed by the post hoc Tukey test (α = 0.05). RESULTS: The highest fracture results were found in group ZR (315.4 ± 53.4 N), which showed significant differences from all other groups (p<0.05). The lowest test values were found in group C (230.2 ± 29.8 N). Group LS (250.9 ± 29.0 N), group CM (253.0 ± 22.4 N) and group C did not show any significant differences (p>0.05). CONCLUSIONS: Custom-made zirconia 1-piece posts and cores, fabricated using the CAD-CAM procedure, can be an alternative treatment method when compared with other techniques.