Adaptación marginal de tres cementos biocerámicos / Marginal adaptation of three bioceramic-based sealers

Objetivo. Evaluar la interfase entre tres cementos biocerámicos y la pared del conducto radicular, comparándolos con un cemento de resina. Material y Métodos: Se seleccionaron 80 dientes unirradiculares, los cuales se dividieron en 4 grupos de acuerdo al cemento de obturación: 1 (MTA FillApex), 2 (EndoSequence BC Sealer), 3 (Bio Root) y 4 (AHPlus). Los dientes se decoronaron dejando una longitud estándar de 15 mm; se instrumentaron con el sistema Mtwo hasta la lima 35/.04. Se irrigó con hipoclorito al 5’25%, EDTA al 17% y se finalizó la irrigación con solución salina. La obturación se realizó con gutapercha 35/.04 y técnica de cono único. Las muestras fueron cortadas a 3, 5 y 8 mm del ápice y se observaron con un estereomicroscopio. Obtenidas las imágenes, se midió el perímetro del conducto en el que hubo adaptación del cemento (expresado como porcentaje respecto a la longitud total del perímetro del conducto) a tres niveles: apical, medio y coronal. Los resultados se analizaron mediante el test de Kruskal Wallis, con una significación de p < 0,05. Resultados: El grupo 1 presentó significativamente peor adaptación a las paredes dentinarias que el resto de cementos estudia-dos en todos los tercios (apical, 63,71%; medio, 69,53%; coronal, 50,82%). Aunque no se encontraron diferencias significativas, el tercio que mejor adaptación presentó fue el apical. Conclusiones: MTA Fillapex, globalmente, se comportó significativamente peor que los otros cementos evaluados. No existen diferencias significativas entre la adaptación a las paredes dentinarias del BioRoot y el Endosequence y el AHPlus

Objective: To evaluate the interface between three bioceramic-based sealers and the root canal wall, comparing them with a resin-based sealer. Material and Methods: 80 single-rooted teeth were selected and divided into 4 groups according to the sealer: 1 (MTA FIllapex), 2 (EndoSequence BC Sealer), 3 (Bio Root) y 4 (AHPlus). Crowns were sectioned at 15mm from the apex; all the roots were instrumented with Mtwo system until 35/.04 file. Canals were irrigated with 5’25% sodium hypochlorite, 17% EDTA and a final rinse with saline solution. The roots were obturated with 35/.04 gutta-percha and single-cone technique. The samples were sectioned at 3, 5 and 8 mm from the apex and were observed with a stereo microscope. The images taken were analyzed; the root canal perimeter where there was adaptation was measure (expressed as a percentage regarding to the root canal total perimeter) at three levels: apical, middle and coronal. The results were analyzed statistically by the Kruskal Wallis test with a p<0,05 significance level. Results: Group 1 presented significantly worst adaptation to the canal walls than the other studied sealers (apical, 63,71%; middle, 69,53%; coronal, 50,82%). The third with the worst adaptation was the apical, even though there were no statistical differences. Conclusions: MTA Fillapex, overall, behaved worse than the other sealers studied. There was no statistical difference between AH Plus, BioRoot and EndoSequence on the canal wall adaptation

Use of antibiotics by spanish dentists receiving postgraduate training in endodontics.

BACKGROUND: The incidence of endodontic infections is high. The contribution of Endodontics to the global problem of antibiotic resistance could be significant. The ESE, together with the World Health Organization, are promoting the World Antibiotic Awareness Week (13-19 November 2017) to promote the appropriate use of systemic antibiotics in Endodontics. The objective of this study was to determine the prescription pattern of antibiotics in the treatment of endodontic infections of Spanish dentists attending specialization programs in Endodontics. MATERIAL AND METHODS: Dentists from five Spanish endodontic postgraduate programs were requested to answer a one-page questionnaire surveying about antibiotics indications. Seventy-three dentists were required to participate in this investigation, and 67 (91.2%) fulfilled satisfactorily the survey and were included in the study. Data were analyzed using descriptive statistics and chi square test. RESULTS: The average duration of antibiotic therapy was 6.8±1.2 days. All respondents chose amoxicillin as first choice antibiotic in patients with no medical allergies, alone (40%) or associated to clavulanic acid (60%). The first drug of choice for penicillin allergic patients was clindamycin (72%). For cases of irreversible pulpitis, 22% of respondents prescribed antibiotics. For the scenario of a necrotic pulp, symptomatic apical periodontitis and no swelling, 37% prescribed antibiotics. A quarter of dentists prescribed antibiotics for necrotic pulps with asymptomatic apical periodontitis and a sinus tract. CONCLUSIONS: The results of this study show that postgraduate training in Endodontics provides greater awareness of the correct indications of antibiotics. Dentists who have received specialized training in Endodontics have a prescription pattern of antibiotics more adjusted to the guidelines recommended by international organizations and by scientific societies. Key words:Antibiotics, apical periodontitis, dental curriculum, endodontic infections, postgraduate endodontic training.

Orthokeratinized odontogenic cysts: a Spanish tertiary care centre study based on HPV DNA detection.

BACKGROUND: The role of human papillomavirus (HPV) in orthokeratinized odontogenic cysts (OOCs) has rarely been studied. The objective is to describe the clinicopathological findings in a series of OOCs from a Spanish population that were investigated in relation to the possible presence of HPV. METHODS: A clinicopathological retrospective analysis followed by a molecular analysis of 28 high- and low-risk HPV genotypes was performed in OOC samples of patients seen during the last 15-years in a Spanish tertiary care center. RESULTS: Of 115 odontogenic cysts with keratinization, 16 cases of OOCs were confirmed and evaluated. OOCs occurred predominantly in the mandible of males (mean age 36.06 ± 13.16 years). Swelling of the jaw followed by pain were the most common clinical symptoms, and 56.5% of the OOC cases were associated with an unerupted tooth. After a mean post-cystectomy follow-up of 3.8 years, only one recurrent case was observed, resulting in a verrucous cystic lesion that was considered premalignant after immunohistological examination. DNA extraction was successful from 14 of the 16 OOC cases. None of the primary OCCs or the single recurrent OOC were positive for HPV in the molecular analysis. CONCLUSIONS: OOCs show a very limited potential for recurrence. Our results suggest that neither high- or low-risk HPV subtypes are likely to play a role in the etiology or neoplastic transformation of OOC, at least in the Spanish population.

Los retos de la endodoncia / The challenges of endodontics

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Immunohistochemical expression of glucose transporter 1 in keratin-producing odontogenic cysts.

BACKGROUND: Keratin-producing odontogenic cysts (KPOCs) are a group of cystic lesions that are often aggressive, with high rates of recurrence and multifocality. KPOCs included orthokeratinised odontogenic cyst (OOC) and parakeratotic odontogenic cysts, which are now considered true tumours denominated keratocystic odontogenic tumours (KCOTs). GLUT1 is a protein transporter that is involved in the active uptake of glucose across cell membranes and that is overexpressed in tumours in close correlation with the proliferation rate and positron emission tomography (PET) imaging results. METHODS: A series of 58 keratin-producing odontogenic cysts was evaluated histologically and immunohistochemically in terms of GLUT1 expression. Different data were correlated using the beta regression model in relation to histological type and immunohistochemical expression of GLUT1, which was quantified using two different morphological methods. RESULTS: KPOC cases comprised 12 OOCs and 46 KCOTs, the latter corresponding to 6 syndromic and 40 sporadic KCOTs. GLUT1 expression was very low in OOC cases compared with KCOT cases, with statistical significant differences when quantification was considered. Different GLUT1 localisation patterns were revealed by immunostaining, with the parabasal cells showing higher reactivity in KCOTs. However, among KCOTs cases, GLUT1 expression was unable to establish differences between syndromic and sporadic cases. CONCLUSIONS: GLUT1 expression differentiated between OOC and KCOT cases, with significantly higher expression in KCOTs, but did not differentiate between syndromic and sporadic KCOT cases. However, given the structural characteristics of KCOTs, we hypothesised that PET imaging methodology is probably not a useful diagnostic tool for KCOTs. Further studies of GLUT1 expression and PET examination in KCOT series are needed to confirm this last hypothesis.

Microscopic assessment of the sealing ability of three endodontic filling techniques.

BACKGROUND: Several techniques have been proposed for root canal filling. New rotary files, with non-standardized taper, are appearing, so, points adapted to the taper of the last instrument used to prepare the canal can help in the obturation process. The aim of this study is to assess the sealing ability of different root canal filling techniques. MATERIAL AND METHODS: Root canals from 30 teeth were shaped with Mtwo and divided in three groups; A, standard lateral condensation with size 35 and 20 gutta-percha points; B, standard lateral condensation and injected gutta-percha; C, single gutta-percha point (standardized 35 Mtwo), continuous wave technique and injected gutta-percha. Root surfaces were covered with nail varnish, except for the apical 2 mm, and submerged in a NO3Ag2 solution; apical stain penetration was measured in mm. Data were compared using the Kruskal-Wallis test with a 90% confidence interval. RESULTS: A and B groups showed stain leakage in the 90% of the cases, whereas it was of 80% for group C. Stain leakage intervals were 1-5 mm for groups A and B and 1-3 mm for group C. There were no statistically significant differences between the three studied groups (p>.05). CONCLUSIONS: All the analyzed root canal filling techniques showed some apical stain leakage, without significant differences among them. KEY WORDS: Gutta-percha filling, microleakage, single cone, injected gutta-percha, warm gutta-percha.

NCAM (CD56) expression in keratin-producing odontogenic cysts: aberrant expression in KCOT.

OBJECTIVE: To investigate immunohistochemically the expression of neural cell adhesion molecule (NCAM), which has been identified as a signaling receptor with frequent reactivity in ameloblastomas (AB), in a series of keratin-producing odontogenic cysts (KPOCs). MATERIAL AND METHODS: Immunohistochemical expression of NCAM, using a monoclonal antibody, was determined in a series of 58 KPOCs comprising 12 orthokeratinized odontogenic cysts (OOCs) and 46 keratocystic odontogenic tumors (KCOTs), corresponding to 40 non-syndromic KCOT (NS-KCOTs) and 6 syndromic KCOT (S-KCOTs), associated with nevic basocellular syndrome (NBCS). RESULTS: NCAM expression was negative in all OOCs, but 36.45% of KCOTs exhibited focal and heterogeneous expression at the basal cell level, as well as in basal budding areas and the basal cells of daughter cysts. The latter two locations were especially applicable to S-KCOTs, with focal NCAM reactivity occurring in 66.66% of cases. CONCLUSIONS: Aberrant NCAM expression, in KCOTs but especially in S-KCOTs, together with its immunomorphological location, suggests that this adhesion molecule and signaling receptor plays a role in the pathogenesis of KCOTs, with a probable impact on lesional recurrence.

Differential expression of Cyclin D1 in keratin-producing odontogenic cysts

OBJECTIVES: The aim of the present study was to analyze the expression levels of Cyclin D1 (CCD1), a nuclear protein that plays a crucial role in cell cycle progression, in a series of keratin-producing odontogenic cysts. Study DESIGN: A total of 58 keratin-producing odontogenic cysts, diagnosed over ten years and classified according to the WHO 2005 criteria, were immunohistochemically analyzed in terms of CCD1 expression, which was quantified in the basal, suprabasal and intermediate/superficial epithelial compartments. The extent of immunostaining was measured as a proportion of total epithelial thickness. Quantified immunohistochemical data were correlated with clinic pathological features and clinical recurrence. RESULTS: Keratin-producing odontogenic cysts were classified as 6 syndromic keratocystic odontogenic tumors(S-KCOT), 40 sporadic or non-syndromic KCOT (NS-KCOT) and 12 orthokeratinized odontogeniccysts (OOC). Immunohistochemically, CCD1 staining was evident predominantly in the parabasal region of all cystic lesions, but among-lesion differences were apparent, showing a clear expansion of parabasal compartment especially in the S-KCOT, followed to a lesser extent in the NS-KCOT, and being much more reduced in the OOC, which had the greatest average epithelial thickness. CONCLUSIONS: The differential expression of CCD1 noted in the present study suggests that dysregulation ofcell cycle progression from G1 to the S phase contributes to the different aggressiveness of these lesions. However, CCD1 expression levels did not predict NS-KCOT recurrence, which is likely influenced by factors unrelated to lesion biology

Differential expression of cyclin D1 in keratin-producing odontogenic cysts.

OBJECTIVES: The aim of the present study was to analyze the expression levels of Cyclin D1 (CCD1), a nuclear protein that plays a crucial role in cell cycle progression, in a series of keratin-producing odontogenic cysts. STUDY DESIGN: A total of 58 keratin-producing odontogenic cysts, diagnosed over ten years and classified according to the WHO 2005 criteria, were immunohistochemically analyzed in terms of CCD1 expression, which was quantified in the basal, suprabasal and intermediate/superficial epithelial compartments. The extent of immunostaining was measured as a proportion of total epithelial thickness. Quantified immunohistochemical data were correlated with clinicopathological features and clinical recurrence. RESULTS: Keratin-producing odontogenic cysts were classified as 6 syndromic keratocystic odontogenic tumors (S-KCOT), 40 sporadic or non-syndromic KCOT (NS-KCOT) and 12 orthokeratinized odontogenic cysts (OOC). Immunohistochemically, CCD1 staining was evident predominantly in the parabasal region of all cystic lesions, but among-lesion differences were apparent, showing a clear expansion of parabasal compartment especially in the S-KCOT, followed to a lesser extent in the NS-KCOT, and being much more reduced in the OOC, which had the greatest average epithelial thickness. CONCLUSIONS: The differential expression of CCD1 noted in the present study suggests that dysregulation of cell cycle progression from G1 to the S phase contributes to the different aggressiveness of these lesions. However, CCD1 expression levels did not predict NS-KCOT recurrence, which is likely influenced by factors unrelated to lesion biology.

Variabilidad morfológica clínica del sistema de conductos de la raíz mesial de los primeros molares mandibulares: análisis de 150 casos / Morphological-clinical variability of the duct system of the mesial root of the mandibular first molars. Analysis of 150 cases

Introducción: El conocimiento de la complejidad del espacio radicular es esencial para el éxito del tratamiento endodóncico. La raíz mesial del primer molar inferior presenta como variante anatómica la existencia de un istmo entre los conductos mesiovestibular y mesiolingual que puede pasar desapercibido o que puede ser trabajado como un conducto suplementario. Objetivo. Clasificar y mostrar el aspecto in vivo de las diferentes morfologías que puede presentar la raíz mesial del primer molar mandibular desde el punto de vista clínico y radiográfico, teniendo presente la permeabilidad del istmo. Material y método. Muestra de 150 primeros molares mandibulares fueron catalogados según los siguientes parámetros: exploración visual de la cámara y aspectos radiográficos durante el tratamiento endodóncico. Resultados. El 82% de los casos evidenció la presencia de dos conductos sin istmo canalizable, aunque visible(istmo rudimentario) en el 40% de los caos. El resto de la muestra (18%) presentó un istmo canalizable (tener conducto) siendo clasificados según el punto de su permeabilización en: lingual (6,7%), vestibular (6%), intermedio (4%) y más de un punto de permeabilidad (1,3%). Conclusiones. La identificación visual de un surco que relaciona los conductos mesiovestibular y mesiolingula obliga al clínico a buscar un espacio por el que permeabilizar, limpiar y obturar el istmo como si de un tercer conducto se tratara. La canalización del istmo se comprueba en la radiografía de conductometría y no en la radiografía final, ya que la superposición del material de obturación hace que no se evidencie frecuentemente la presencia de los tres conductos (AU)

Introduction. The knowledge about the complex anatomy of the radicular space is essential for the success of the endodontic treatment. The mesial root of the permanent mandibular first molar shows isthmus between the mesiobuccal and mesiolingual canals, with different morphologies, that can go unnoticed. Objective. Sort and show in vivo the clinical appearance of different morphologies that may have mesial root of the permanent mandibular first molar in radiographic images and photographs taken during the root canal treatment, taking into account the permeability of the isthmus. Material and methods. 150 mandibular first molar were classified according to visual exploration of the chamber and radiographic images during endodontic treatment. Results. The 82% of total showed the presence of two canals without isthmus channeling, but visible (rudimentary isthmus) in 40% of cases. The rest of the sample (18%) had as isthmus ducted (third canal) being classified according to the permeabilization point: lingual (6,7%), buccal (6%), intermediate (4%) and permeability of more than one point (1,3%). Conclusions. Visual identification of a path that links the mesiobuccal and mesiolingual canals obliges the practitioner to look for a space in order to get patency, cleaning, shaping and filing the isthmus as if it were at third canal. Cahnneling the isthmus is usually found in the working length radiograph and not on the final radiograph as the superposition of the filling material does not often show evidence of the presence of three canals (AU)

Estudio comparativo in vitro de la filtración apical de tres sistemas de obturación radicular / An in vitro comparative study of apical infiltration of three radicular obturation systems

Objetivo: El propósito de este trabajo fue medir y comparar in vitro la microinfiltración apical del colorante de nitrato de plata en conductos radiculares obturados con tres sistemas diferentes: gutapercha normalizada/ AHPlus (GN/AHP); gutapercha de conicidad aumentda /AHPlues (GCA/AHP) y Resilon/Epiphany (R/E). Material y Métodos: Se utilizaron 40 raíces de dientes humanos extraídos. Las raíces se dividieron aleatoriamente en tres grupos experimentales y dos grupos de control. Los conductos fueron preparados biomecánicamente y obturados mediante la técnica de condensación lateral en frío con los 3 sistemas a estudio. Después de estar en una estufa durante 7 días (37ªC, 100% humedad), los especímenes fueron inmersos en nitrato de plata al 50% y sus cortes transversales de 1mm. De grosor, fueron observados a 40x aumentos. Resultados: El grupo I (GN/AHP) infiltró una media de 3mm; el grupo II (GCA/AHP) 2,3 mm y el grupo III (R/E) 2,1 mm. El estudio estadístico basado en el test de Anova indica que no hubo diferencias significativas en la infiltración apical entre los 3 sistemas estudiados (AU)

Objective: The aim of this study was to evaluate and compárate in vitro the apical microleakage of the silver nitrate colorant in root canal with three different obturation systems; Standardized gutta-percha/(AYPlus (SG/AHP); great taper gutta-percha/AHPlus (GTG/AHP) and Resilon/Epiphany (R/E). Materials and Methods: forty roots of extracted teeth were selected. The roots were randomly divided into three experimental groups and two control groups. The root canals were biomechanical prepared and filled with cold lateral condensation with the three study obturation systems. After seven days in an oven (37ºC, 100% humidity), the roots were immersed in 50% silver nitrate, and the transversal cross-section at 1mm, were observed at 40x magnification. Results: Group I (SG/AHP) leakage a mean value of 3mm; group II (GTG/AHP) 2,3 mm, and group III (R/E) 2,1 mm, Styatistic study Based on Anova test, there were no significative difference. Conclusions: R/E was the system with less apical leakage and SG/AHP obtained the higher value. There was no statiscally significant difference in apical leakage among the three obturation systems (AU)

Premolars restored with posts of different materials: fatigue analysis.

Previous works studied the effect of the material and the dimensions of the post on the biomechanical performance (fracture strength and stress distribution) of restored teeth, under static loads. The aim of this work was to study the effect of the post material (glass fibre and stainless steel) on restored teeth, which have the final crown, under dynamic conditions. The use of a biomechanical model, including a fatigue analysis from FEA, is presented as a powerful method to study the effect of the material of the intraradicular post. The inclusion of the fatigue analysis allows for a more realistic study that takes into account the dynamic nature of masticatory forces. At the same time, the results obtained are easier to interpret by both dentists and mechanical engineers. No differences were found, with the load and number of cycles considered, between glass fibre and stainless steel as material for the intraradicular post used in premolars restorations.

Shaping ability of nickel-titanium rotary instruments in simulated S-shaped root canals.

OBJECTIVE: The aim of this study was to compare the shaping ability of 4 nickel-titanium rotary techniques and 1 hand technique in simulated S-shaped curved root canals. STUDY DESIGN: Seventy-five simulated double-curved resin root canals were divided into 5 groups (n = 15). The canals were compared at 12 different levels and at 3 different times: before preparation and after preparation to master apical 25 and 35. Data were statistically analyzed by performing 2-by-2 comparisons with the Tukey parametric test of variance analysis using a confidence interval of 95%. RESULTS: All of the 75 resin blocks presented transportation of the root canals by transforming the apical curvature into a straight zone and straightening the first curvature. When increasing the diameter from 25 to 35, both curvatures were straightened. CONCLUSIONS: Based on the conditions of this study, we can say that the flexibility of the instruments is inversely related with the transportation of the root canals, and that in the double-curved root canals, the apical curvature is always straightened.

Modification of the working length after rotary instrumentation. A comparative study of four systems

Objective: To determine variation in post-instrumentation working length and root area in the following rotary systems: ProTaper, RaCe, Mtwo and K3. Study design: A sample of 40 resin blocks with double curvature (at 14 and 16 mm) and a 33o angle was used. Working length was verified with a digital measure using a number 10 K file. The specific sequence for each rotary system was followed. The canal was measured between each file, and the variation noted to determine which file showed the greatest variation within a same system and the different systems were compared. 1.5 X pre and post-instrumentation microscopic photographs were taken and measurements of the area were taken with an im- age analysis programme. Results: The area was found to increase by the following amounts: ProTaper: 21.85 mm2; Mtwo: 20.16 mm2; K3: 17.24 mm2 and RaCe: 16.09 mm2. The differences in variation of the working length were: ProTaper: 0.81 mm; Mtwo: 1.07 mm; K3: 0.31 mm and RaCe: 0.81 mm Conclusions: The values for the variation in working length are clinically not very significant. All the rotary systems analysed showed a tendency to straighten the canal and eliminate the apical curvature, and the ProTaper system was found to produce the greatest modification to the canal area and structure (AU)

Modification of the working length after rotary instrumentation: a comparative study of four systems.

OBJECTIVE: To determine variation in post-instrumentation working length and root area in the following rotary systems: ProTaper, RaCe, Mtwo and K3. STUDY DESIGN: A sample of 40 resin blocks with double curvature (at 14 and 16 mm) and a 33 degrees angle was used. Working length was verified with a digital measure using a number 10 K file. The specific sequence for each rotary system was followed. The canal was measured between each file, and the variation noted to determine which file showed the greatest variation within a same system and the different systems were compared. 1.5 X pre and post-instrumentation microscopic photographs were taken and measurements of the area were taken with an image analysis programme. RESULTS: The area was found to increase by the following amounts: ProTaper: 21.85 mm2; Mtwo: 20.16 mm2; K3: 17.24 mm2 and RaCe: 16.09 mm2. The differences in variation of the working length were: ProTaper: 0.81 mm; Mtwo: 1.07 mm; K3: 0.31 mm and RaCe: 0.81 mm. CONCLUSIONS: The values for the variation in working length are clinically not very significant. All the rotary systems analysed showed a tendency to straighten the canal and eliminate the apical curvature, and the ProTaper system was found to produce the greatest modification to the canal area and structure.

Cutting efficiency evaluation of Quantec Series 2000 orifice openers with computed tomography (CT).

INTRODUCTION: Orifice openers or orifice shapers are used to shape the coronal part of the root canals during endodontic treatment. OBJECTIVES: The aim of this work was to analyse the cutting efficiency of Quantec Series 2000 system orifice shapers by means of computerised tomography (CT). MATERIALS AND METHODS: Mandibular molars were selected, preoperative CT was performed and the cross-sections and surface area of the root canals were measured. Following access opening and preparation of the coronal part of the canals with Quantec Series 2000 orifice shapers, a further CT was obtained of all the teeth, the previous measurements were repeated and the two sets of measurements were compared. RESULTS: Although the canals suffered modifications due to the action of the instruments, they remained centred and retained their original morphology; the changes were greater in the most coronal part of the canals. CONCLUSIONS: the orifice shapers of the system under study kept the canals centred on their original position, so they do not present great aggressiveness during endodontic treatment; the canals that were initially the widest were those that showed the greatest modification; the CT system employed in the study showed itself to be an effective, non-invasive system for studying the changes that had taken place inside the root canals.

Cutting efficiency evaluation of Quantec Series 2000 orifice openers with computed tomography (CT)

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Introduction: Orifice openers or orifice shapers are used to shape the coronal part of the root canals during endodontic treatment. Objectives: The aim of this work was to analyse the cutting efficiency of Quantec Series 2000 system orificeshapers by means of computerised tomography (CT). Materials and methods: Mandibular molars were selected,preoperative CT was performed and the cross-sections and surface area of the root canals were measured. Followingaccess opening and preparation of the coronal part of the canals with Quantec Series 2000 orifice shapers, a further CT was obtained of all the teeth, the previous measurements were repeated and the two sets of measurements were compared. Results: Although the canals suffered modifications due to the action of the instruments, they remainedcentred and retained their original morphology; the changes were greater in the most coronal part of the canals.Conclusions: the orifice shapers of the system under study kept the canals centred on their original position, so they do not present great aggressiveness during endodontic treatment; the canals that were initially the widest were those that showed the greatest modification; the CT system employed in the study showed itself to be an effective, noninvasive system for studying the changes that had taken place inside the root canals (AU)

Evidence concerning the medical management of caries.

Caries is an infectious, chronic and cumulative disease. It seriously affects quality of life and creates considerable expense for individuals and communities. The disease can be managed by acting on biofilm formation and maturation, by modifying the kinetics of apatite solution or with a combination of the two processes. This can be achieved by mechanical and chemical control of plaque, appropriate use of fluorides, controlling diet and salivary flow, when possible. Many of these factors depend on the patient's co-operation. Decisions concerning treatment are influenced by two questions: the scientific evidence for the different alternatives available and each patient's individual caries risk. The use of different fluoride regimes, depending on the individual risk, remains the most scientifically proven method for avoiding the appearance of new lesions and curbing the speed at which existing ones progress. Chemical control of plaque using chlorhexidine is indicated for patients at high microbiological risk; it is more effective at controlling caries when used in combination with fluorides. Fissure sealing is an effective means of controlling occlusal caries of the molars when the patient's caries risk and the eruptive age of the tooth are taken into account.

Evidence concerning the medical management of caries

Caries is an infectious, chronic and cumulative disease. It seriously affects quality of life and creates considerable expense for individuals and communities.The disease can be managed by acting on biofilm formation and maturation, by modifying the kinetics of apatitesolution or with a combination of the two processes. This can be achieved by mechanical and chemical control ofplaque, appropriate use of fluorides, controlling diet and salivary flow, when possible. Many of these factors depend on the patient’s co-operation.Decisions concerning treatment are influenced by two questions: the scientific evidence for the different alternatives available and each patient’s individual caries risk.The use of different fluoride regimes, depending on the individual risk, remains the most scientifically proven method for avoiding the appearance of new lesions and curbing the speed at which existing ones progress. Chemical control of plaque using chlorhexidine is indicated for patients at high microbiological risk; it is more effective at controlling caries when used in combination with fluorides. Fissure sealing is an effective means of controlling occlusal caries ofthe molars when the patient’s caries risk and the eruptive age of the tooth are taken into account (AU)

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Diagnostic performance of radiovisiography in combination with a diagnosis assisting program versus conventional radiography and radiovisiography in basic mode and with magnification.

OBJECTIVE: To evaluate and compare the diagnostic efficiency of a digital radiographic system (RadioVisioGraphy -RVG-) in combination with a diagnostic assisting program (Logicon) with RVG in basic mode, magnification and conventional radiography (Kodak). STUDY DESIGN: A study was made of 384 proximal surfaces corresponding to 192 posterior teeth. The diagnostic techniques employed comprised Kodak DF-58 Ultraspeed X-rays and a Trophy RVG system used in normal mode, magnification, combination with a caries diagnosis assisting program by Logicon; Kodak DF-58 Ultraspeed radiographs were used. The same X-ray source was used in all cases. The images obtained were compared to histological sections of the teeth used. These were brewed by abrasion and observed using a light microscope. A single operator made all observations. Sensitivity, specificity, the positive and negative predictive values, and the probability ratio were calculated. RESULTS: Application of the Logicon program increased sensitivity, specially in lesions with caries extending into the dentin. In contrast, conventional radiography yielded a higher specificity and positive predictive value. The negative predictive values were similar for both techniques. CONCLUSIONS: The RVG digital radiography and the Logicon assistance program was effective in diagnosing caries.