The accuracy of estimating chronological age from Demirjian and Nolla methods in a Portuguese and Spanish sample.

BACKGROUND: Age determination has great importance in many clinical decisions, being commonly used in odontopediatrics, orthodontics, pediatrics, and forensic medicine. The Nolla and Demirjian et al. methods have been used for these purposes. However, estimating chronological age by means of the dental mineralization stage is not a straightforward analysis, and it is fundamental to test the validity of these methods and their applicability to populations. In this article we intend to compare the accuracy of estimating chronological age from dental age measured with the Nolla and Demirjian methods in a Portuguese and Spanish sample, considering the variables of sex and age-group. METHODS: The sample was composed of 821 orthopantomographs of healthy Portuguese (n = 270) and Spanish (n = 551) subjects from 4 to 34 years old. For the Nolla and Demirjian methods, seven mandibular left teeth were examined, staged according to the dental maturity scale of each method. We obtained a good index of inter-rater agreement, a good internal consistency for the teeth assessment, and a good temporal consistency. RESULTS: Dental age was calculated for each method. The Demirjian et al. method tends to overestimate the real age of participants and the Nolla method tends to underestimate it. The accuracy of both methods varied between the sexes and age groups. Both methods were found to be more precise with males. As the age-group increases, the predictive capacities of both methods diminish. The Nolla method was more accurate than the Demirjian method in early and late childhood for both sexes. Neither method could predict chronological age in adults. CONCLUSIONS: We can estimate chronological age for early and late childhood, through the Nolla and Demirjian methods, with the former showing greater predictive capacities than the latter. The Demirjian method tends to overestimate age and the Nolla method tends to underestimate it, leading to the importance of forming regression equations adapted to the population studied. Nolla and Demirjian formulas adapted to our sample were created as a function of sex and age-group.

Adapting Demirjian Standards for Portuguese and Spanish Children and Adolescents.

Estimation of children's chronological age is highly important in human and forensic sciences. The Demirjian method has been reported as accurate for this purpose. The literature review shows some evidence that the accuracy of estimating chronological age via the Demirjian standards is not a straightforward process. The objective of this research is to analyze the reliability of the Demirjian standards in Portuguese and Spanish children and adolescents and adapt it to include sex and group age as contingent factors. METHODS: Orthopantomographs of 574 Portuguese and Spanish male and female children and adolescents were employed to test the reliability of the Demirjian method. After testing for inter-rater consistency and age estimation using the Demirjian standards, multiple regression analysis was performed controlling for sex and age group. RESULTS: The Demirjian standards overestimated chronological age for both sexes, mainly for females. Through the development of regression functions, more detailed dental age estimation was performed. The predictive capacities of the Demirjian method and the significant teeth varied as a function of children's age. The Demirjian global standard predicted over 65% of the variance of the chronological age. Taking a tooth-by-tooth approach, the predictive ability increased by over 70%. CONCLUSIONS: The accuracy of estimating chronological age via the Demirjian method is not as reliable as it might appear, judging from the results found according to age group and according to sex crossed with age group.

Fracture and deformation of ProTaper Next instruments after clinical use.

BACKGROUND: The aim of this study was to evaluate the fracture and defects observed in ProTaper Next files discarded after a normal clinical use. MATERIAL AND METHODS: 571 ProTaper Next rotary instruments were collected after clinical use from the clinic of endodontics over 12 months. The length of the files was measured using a digital caliper to determine any fracture, later all the files were evaluated under a stereomicroscope to observe defects such as unwinding, curving or fracture. The data obtained were analyzed using a chi-square and z test. RESULTS: 13.83% of the discarded files showed defects, the most frequent defect was fracture (7.53%). The highest rate of fracture was observed in the X1 (17.04) files (19.87%). The presence of deformations without fracture was also more frequent in the 17.04 file (11.8%). CONCLUSIONS: Because of the relatively high incidence of deformation of smaller files, these instruments should be considered as a single use. It is important not to exceed the maximum uses recommended by the manufacturer to reduce the risk of cyclic fatigue, the main cause of fracture of the files (79.07%). It is also important to observe each file after use to discard small defects or fractures. Key words:Clinical use, deformation, fracture, M-Wire, ProTaper Next.

Vertical Root Fracture initiation in curved roots after root canal preparation: A dentinal micro-crack analysis with LED transillumination.

BACKGROUND: One of the causative factors of root defects is the increased friction produced by rotary instrumentation. A high canal curvature may increase stress, making the tooth more susceptible to dentinal cracks. The purpose of this study was to evaluate dentinal micro-crack formation with the ProTaper NEXT and ProTaper Universal systems using LED transillumination, and to analyze the micro-crack generated at the point of maximum canal curvature. MATERIAL AND METHODS: 60 human mandibular premolars with curvatures between 30-49° and radii between 2-4 mm were used. The root canals were instrumented using the Protaper Universal® and Protaper NEXT® systems, with the aid of the Proglider® system. The obtained samples were sectioned transversely before subsequent analysis with LED transillumination at 2 mm and 8 mm from the apex and at the point of maximum canal curvature. Defects were scored: 0 for no defects; and 1 for micro-cracks. RESULTS: Root defects were not observed in the control group. The ProTaper NEXT system caused fewer defects (16.7%) than the ProTaper Universal system (40%) (P<0.05). The ProTaper Universal system caused significantly more micro-cracks at the point of maximum canal curvature than the ProTaper NEXT system (P<0.05). CONCLUSIONS: Rotary instrumentation systems often generate root defects, but the ProTaper NEXT system generated fewer dentinal defects than the ProTaper Universal system. A higher prevalence of defects was found at the point of maximum curvature in the ProTaper Universal group. Key words:Curved root, Micro-crack, point of maximum canal curvature, ProTaper NEXT, ProTaper Universal, Vertical root fracture.

Alternating versus continuous rotation: Root canal transportation and centering ratio with the ProTaper Next.

BACKGROUND: The technique of alternating rotation has been used with NiTi rotary instruments to increase the resistance to fracture compared with conventional continuous rotation. However, it is still not clear what type of instrumentation could provide better results in the preservation of the original canal anatomy. AIM: The aim of this study is to determine the influence of the type of rotation on canal transportation and centering ability using cone-beam computed tomography (CBCT) imaging. MATERIALS AND METHODS: In total, 50 mesial canals of mandibular molars with curvatures between 30° and 60° were divided into two experimental groups (n = 25 each) according to the type of movement employed with the ProTaper Next (PTN) instruments: Group A (alternating rotation) and Group B (continuous rotation). Canals were scanned before and after instrumentation using a CBCT scanner to evaluate root canal transportation and the centering ratio at 3, 5, and 7 mm from the apex. Data were analyzed statistically using Student's t-test; the significance level was set at P < 0.05. RESULTS: There was no significant difference between the groups in canal transportation or the centering ratio at any of the three studied cross sections (3, 5, and 7 mm). CONCLUSIONS: PTN instruments promoted minimal apical transportation and remained relatively centered within the root canal, with no significant difference between alternating and continuous rotation.

Continuous Apical Negative-Pressure Ultrasonic Irrigation (CANUI): A new concept for activating irrigants.

BACKGROUND: Irrigation of the root canal system is an essential step in the endodontic treatment. The aim of this article is to introduce continuous apical negative-pressure ultrasonic irrigation (CANUI), a new irrigation concept, and compare the characteristics of this new technique with current devices for activating the irrigant. MATERIAL AND METHODS: CANUI is designed for cleaning and disinfecting the root canal system. The device consists of a tube inside another tube that allows the continuous ultrasonic exchange of fresh irrigant, as the irrigant is simultaneously aspirated apically. The coronal and apical tubes are 0.75 and 0.3 mm in diameter, respectively. It is composed of a nickel-titanium microcannula suitable for the working length of curved canals. RESULTS: The CANUI technique has the advantages of apical negative pressure (to avoid apical extrusion of the irrigant) and continuous ultrasonic irrigation (continuous refreshment of the irrigant and forced introduction into the canal ramifications). CONCLUSIONS: The CANUI technique could improve the irrigation technique of dentists to reach more disinfection in endodontic treatments. Key words:Apical negative pressure, continuous ultrasonic irrigation, irrigation in curved canals, irrigation systems.

Management of large class II lesions in molars: how to restore and when to perform surgical crown lengthening?

The restoration of endodontic tooth is always a challenge for the clinician, not only due to excessive loss of tooth structure but also invasion of the biological width due to large decayed lesions. In this paper, the 7 most common clinical scenarios in molars with class II lesions ever deeper were examined. This includes both the type of restoration (direct or indirect) and the management of the cavity margin, such as the need for deep margin elevation (DME) or crown lengthening. It is necessary to have the DME when the healthy tooth remnant is in the sulcus or at the epithelium level. For caries that reaches the connective tissue or the bone crest, crown lengthening is required. Endocrowns are a good treatment option in the endodontically treated tooth when the loss of structure is advanced.

In vitro comparison of passive and continuous ultrasonic irrigation in curved root canals.

BACKGROUND: The efficacy of endodontic irrigation procedures can be compromised by the complexity of the root canal system. Delivering irrigants to the apical third of curved canals presents a particular challenge to endodontists. This study compared the effects of two ultrasonic irrigation techniques on the penetration of sodium hypochlorite into the main canal and simulated lateral canals of curved roots in extracted teeth. MATERIAL AND METHODS: Two sets of simulated lateral canals were created at 2, 4, and 6 mm from the working length in 60 single-rooted teeth (6 canals/tooth, n = 360 canals). The teeth were randomly divided into three experimental irrigation groups: group 1 (n = 20), positive pressure irrigation (PPI); group 2 (n = 20), passive ultrasonic irrigation (PUI); and group 3 (n = 20), continuous ultrasonic irrigation (CUI). To assess the irrigation solution penetration, 20% Chinese ink (Sanford Rotring GmbH, Hamburg, Germany) was added to a 5% sodium hypochlorite solution and delivered into the curved root canals. The penetration of contrast solution into the simulated lateral canals was scored by counting the number of lateral canals (0-2) penetrated to at least 50% of the total length. RESULTS: The CUI group showed significantly higher (P < 0.05) irrigant penetration into the lateral canals and into the apical third of the main canals. The PPI group showed significantly lower sodium hypochlorite penetration (P < 0.001) into the main and lateral canals compared with that in the CUI and PUI groups. Significantly higher irrigant penetration was observed in the PUI group than the PPI group. CONCLUSIONS: Using CUI as the final rinse significantly increased the penetration of irrigant solution into the simulated lateral canals and apical third of curved roots. Key words:Continuous ultrasonic irrigation, curved root canals, passive ultrasonic irrigation, positive pressure irrigation, root canal irrigation.

Comparative study of root canals instrumented manually and mechanically, with and without Er:YAG laser.

OBJECTIVE: The aim of this study was to compare the scanning electron microscopic (SEM) morphology of root canal walls instrumented manually and mechanically with and without the application of Er:YAG laser. METHODS: Single-rooted, human, extracted teeth were cut at the cementoenamel junction. The teeth were divided into four groups: teeth that were simply instrumented manually, those that were instrumented manually and laser treated, a group that was mechanically instrumented, and a fourth in which the teeth were mechanically instrumented and laser treated. After instrumentation, the teeth were split longitudinally to facilitate their evaluation by SEM. RESULTS: The results show that the use of the Er:YAG laser is effective in removing the smear layer from root canal walls. CONCLUSIONS: The removal of the smear layer is essential to the success of endodontic treatment; the use of the Er:YAG laser combined with rotary and manual techniques improves the cleanliness of root canals.

Combined Endodontic-Periodontal Treatment of a Palatogingival Groove.

A palatogingival groove is a developmental anomaly that predisposes the involved tooth to develop a severe periodontal lesion. These grooves often present a clinical challenge because diagnosis and treatment planning require an interdisciplinary approach. This case report describes the successful management of a right maxillary lateral incisor with a deep palatogingival groove in combination with an extensive periodontal pocket and pulp necrosis of the involved tooth. Collaborative management used a combination of endodontic treatment, periodontal therapy, odontoplasty, and a periodontal regenerative procedure using protein complex derived from enamel matrix (Emdogain; Straumann, Basel, Switzerland). Despite a predicted poor prognosis, the tooth lesion healed. This report also discusses the rationale behind the treatment modalities.

Unusual root morphology in second mandibular molar with a radix entomolaris, and comparison between cone-beam computed tomography and digital periapical radiography: a case report.

INTRODUCTION: Radix entomolaris presents with an unusual morphology and is a rare occurrence. It is mainly observed in mandibular first molars. The incidence varies in different populations but it is far from common. This is especially true for mandibular second molars which possess the lowest prevalence. Some case reports have shown the presence of this finding in mandibular second molars; however, cases of patients of a white background have not been reported. CASE PRESENTATION: The diagnosis and treatment of an infected radix entomolaris in a mandibular second molar in a 45-year-old white man is presented. The diagnosis was made with standard endodontic techniques. Conventional radiographic imaging was augmented with cone-beam computed tomography scans and three-dimensional images which were constructed with dedicated software. The endodontic treatment was done using accepted endodontic procedures. Clinical and radiographic evidence of healing was seen after a 14-month follow-up. CONCLUSIONS: The implications of complex and unpredictable root anatomy are discussed in this report. The clinician should consider the possibility of encountering a mandibular second molar with a radix entomolaris. Cone-beam computed tomography is a useful tool in the diagnosis and improvement of root canal therapy.

Ultramicroscopic study of the interface and sealing ability of four root canal obturation methods: Resilon versus gutta-percha.

Recently, filling materials have been introduced based on the dentine adhesion technologies used in conservative dentistry in an attempt to seal the root canal more effectively. The purpose of this study was to investigate the interface between the canal and root-filling material. Sealing ability of four root canal obturation methods was analysed by means of scanning electron microscopy. Extracted single-rooted teeth were endodontically treated and filled with gutta-percha/Pulp Canal Sealer using the Thermafil (TH) technique, gutta-percha/Pulp Canal Sealer using the System B (SB) technique, Resilon points/RealSeal (RS) and RealSeal 1/RealSeal (RS1). Specimen interfaces were analysed using field-emission scanning electron microscopy. The adhesive groups RS and RS1, formed hybrid layers but showed areas of separation (gaps) similar to those in the conventional obturation groups. The RS and RS1 groups showed less separation in the coronal third, but the separation was similar to that in the TH and SB groups in the middle and apical thirds. The sealing ability of Resilon is not superior to that of existing materials.

In vitro comparison of passive and continuous ultrasonic irrigation in simulated lateral canals of extracted teeth.

INTRODUCTION: Complete endodontic system disinfection requires the removal of vital and necrotic pulp tissue, microorganisms, and toxins. The purpose of this study was to compare the effects of 2 ultrasonic irrigation techniques on the penetration of sodium hypochlorite into the main canal and simulated lateral canals of extracted teeth. METHODS: Two simulated lateral canals each were created 2, 4, and 6 mm from the working length in 60 single-rooted teeth (6 canals/tooth, n = 360). To resemble the clinical situation, a closed system was created in each tooth. The teeth were randomly assigned to 3 experimental irrigation groups: group 1 (n = 20), positive pressure irrigation (PPI); group 2 (n = 20), passive ultrasonic irrigation (PUI); and group 3 (n = 20), continuous ultrasonic irrigation (CUI). Samples were evaluated by direct observation of still images recorded under a dental operating microscope. To examine irrigating solution penetration, 20% Chinese ink (Sanford Rotring GmbH, Hamburg, Germany) was added to a 5% sodium hypochlorite solution and delivered into the root canals. RESULTS: The results showed a significantly higher (P < .05) penetration of irrigant into the lateral canals in the CUI group. PUI and CUI did not differ significantly in solution penetration into the apical thirds of the main canals. The PPI group showed a significantly lower penetration of sodium hypochlorite into the main and lateral canals compared with the CUI and PUI groups. CONCLUSIONS: CUI as a final rinse significantly increased the penetration of irrigating solution into simulated lateral canals.

Identificación de microorganismos por reacción en cadena de la polimerasa en necrosis pulpar y periodontitis apical / Identification of microorganisms by polymerase chain reaction in pulp necrosis and apical periodontitis

Objetivos: identificar, mediante la técnica de reacción en cadena de la polimerasa, diez especies bacterianas procedentes de conductos radiculares necróticos, así como analizar su asociación con signos y síntomas de la periodontitis apical (dolor, exudado y movilidad), dentro de un área geográfica específica, Santiago de Compostela (noroeste de España). Métodos: se realizó un estudio descriptivo, en un plazo de recogida de muestras de un año. Se extrajeron 43 muestras de los conductos radiculares necróticos, a razón de una muestra por pacientes, quienes fueron examinados previamente para determinar la presencia de periodontitis apical radiográfica, de la cual fueron descritos sus signos y síntomas. Se utilizaron puntas de papel absorbentes estériles y se procedió a extraer de dichas muestras el ADN por medio de la técnica del fenol-cloroformo. El producto se amplificó por medio de la reacción en cadena de la polimerasa, usando cebadores específicos para diez microorganismos. El resultado se visualizó por medio de electroforesis, utilizando un transiluminador UV. Los resultados se analizaron estadísticamente, para así establecer qué microorganismos estaban presentes de forma individual y cuáles se presentaron formando asociaciones como el llamado red complex, en relación con los signos y síntomas presentes en la periodontitis apical. Resultados: Fusobacterium nucleatum fue el microorganismo con presencia de forma individual más frecuente (83,72 por ciento de las muestras). En cuanto al estudio de la asociación de los microorganismos con los signos y síntomas, Porphyromonas endodontalis presentó una asociación significativa con respecto al exudado (p< 0,05) y movilidad (p< 0,05). En cambio, Enterococcus spp. y Treponema denticola (p< 0,01) presentaron ambos una asociación significativa con respecto al dolor. En cuanto a la incidencia del red complex fue de 6 casos en total. Conclusiones: Fusobacterium nucleatum y Streptococcus spp. son los microorganismos identificados con mayor porcentaje en comparación a los restantes estudiados. Porphyromonas endodontalis es el microorganismo con mayor asociación estadística con respecto a los signos y síntomas de la periodontitis apical(AU)

Objectives: identify by polymerase chain reaction technique ten bacterial species obtained from necrotic root canals, and analyze their association with signs and symptoms of apical periodontitis (pain, exudate and mobility) in a specific geographic area: Santiago de Compostela (northwestern Spain). Methods: a descriptive study was conducted based on a one-year sample collection period. Forty-three samples were taken from necrotic root canals, at a rate of one sample per patient, who had been previously examined for radiographic apical periodontitis, of which the signs and symptoms were described. Sterile absorbent paper points were used to extract the DNA samples, applying the phenol-chloroform technique. The product was amplified by polymerase chain reaction, using specific primers for ten microorganisms. The result was visualized by electrophoresis using a UV transilluminator. Outcomes were analyzed statistically to determine which microorganisms were present individually and which formed associations such as the so-called red complex, according to the signs and symptoms present in the apical periodontitis. Results: Fusobacterium nucleatum was the most common individual microorganism (83.72 percent of the samples). As to the association of microorganisms with signs and symptoms, Porphyromonas endodontalis was found to be significantly associated with exudate (p< 0.05) and mobility (p< 0.05), while both Enterococcus spp. and Treponema denticola (p< 0.01) had a significant association with pain. Incidence of the red complex was 6 cases in all. Conclusions: Fusobacterium nucleatum and Streptococcus spp. were the microorganisms identified as displaying the highest percentages. Porphyromonas endodontalis showed the greatest statistical association with signs and symptoms of apical periodontitis(AU)

Colorimeter and scanning electron microscopy analysis of teeth submitted to internal bleaching.

INTRODUCTION: This in vitro study compared the tooth color and the ultrastructure of internal dental tissues before and after internal bleaching. METHODS: Sodium perborate was placed in the pulp chamber of endodontically treated molars and sealed with intermediate restorative material. The test samples were stored in a physiologic solution, and the bleaching agent was replaced every 7 days. A control group was used. After 1 month, the colors of the test and control samples were measured with a colorimeter, and the internal surfaces were observed under field emission scanning electron microscopy (FESEM). RESULTS: Statistically significant differences were found between the test and control sample colors. The FESEM ultrastructure analysis of the internal enamel and dentin surfaces did not show any changes after the internal bleaching. CONCLUSIONS: The results of the present study show that sodium perborate is effective in bleaching nonvital teeth and does not produce ultrastructural changes in the dental tissues.

Alternating versus continuous rotation: a comparative study of the effect on instrument life.

INTRODUCTION: Rotary nickel-titanium instruments have multiple advantages but with the risk of more fractures because of flexure or torsion. Alternating rotation appears to be an alternative to continuous rotary movement. The objective of this study was to determine the influence of the type of instrument rotation on the frequency of fractures or deformation. METHODS: Instrumentation was performed on 120 molar root canals with an angle of curvature greater than 30 degrees using alternating rotation (group A: 60 degrees clockwise, 45 degrees counterclockwise) and continuous rotation (group B). RESULTS: The results indicate that instruments used with alternating rotation have a higher mean number of uses (13.0) compared with the continuous rotation group (10.05); this difference was statistically significant (p < 0.05). CONCLUSIONS: The ProTaper shaping instruments (S1 and S2) are those that achieved the greatest difference in use with alternating rotation, with S2 being the most resistant to fracture or deformation with the two types of movement used.

A comparative study of microleakage through enamel and cementum after laser Er:YAG instrumentation in class V cavity obturations, using scanning electron microscopy.

OBJECTIVE: The purpose of this study was to use scanning electron microscopy (SEM) in order to compare the surfaces of cavities prepared using laser with those prepared conventionally, and to measure the degree of leakage through both enamel and cementum. MATERIALS AND METHODS: We prepared 135 class V cavities and divided them randomly into three groups: laser-treated (group A), laser-treated, and acid-etched (group B) and rotary instrumented (group C). RESULTS: On analyzing the tooth enamel, the amount of leakage was found to be similar in groups A and B, whilst the samples in the group C were more prone to leakage. On analyzing the cementum, the group C samples appeared to display surfaces that were more conducive to the adhesion of the materials used in obturation (although this difference was not strictly significant), and this might have provoked the relatively low levels of leakage. CONCLUSION: The use of acid etching in conjunction with both conventional and laser cavity preparation improves the adhesion of the materials used in obturation to enamel surfaces.