Influence of concentration, irrigation method, and root canal third on intratubular penetration of sodium hypochlorite - a broad statistical analysis.

Background: The permanence of microorganisms in the root canal system represents the main cause of endodontic failure. Considering the impossibility of effective action of the endodontic files in ramifications of the main canal and mainly inside the dentinal tubules, a better understanding of the irrigation dynamics to enhance endodontic prognosis is essential. Objective: To evaluate the depth of intratubular penetration values of sodium hypochlorite (NaOCl) (dependent variable) by comparing different concentrations, methods of irrigation, and root canal thirds (independent variables) and to investigate the existence of interactions among them, capable of influencing the dependent variable. Material and Methods: 40 roots from extracted human maxillary central incisors were stained and instrumented according to four irrigation protocols (n. 10): conventional irrigation (CI) at each use or change of instrument, and final irrigation with 5ml of 2.5% or 5.25% NaOCl, with or without passive ultrasonic irrigation (PUI), respectivelly. Measurements based on stereomicroscopic images were obtained, and the data were subjected to statistical analysis (p< 0.05). Results: The highest depth values of intratubular penetration of NaOCl were observed in the cervical third, at 5.25%, and by PUI. When only two independent variables were analyzed in association, the highest penetration depth values of NaOCl were obtained at 5.25%, regardless of irrigation method, at 5,25%, in the cervical third, and; in the cervical third, despite of irrigation method. Considering the three independent variables simultaneously, the highest depth values of intratubular penetration of NaOCl were observed in the cervical third, at 5.25%, no matter the irrigation method. The interaction between the independent variables on the penetration depth values of NaOCl was only confirmed considering the irrigation method and root canal third. Conclusions: Intratubular penetration of NaOCl was influenced by the three independent variables individually and when the irrigation method and root canal third were considered simultaneously. Key words:Dentinal tubules, Depth, Disinfection, Irrigation, Root canal system, Sodium hypochlorite.

Postoperative pain after endodontic treatment of necrotic teeth submitted to large apical preparation using oscillatory kinematics.

BACKGROUND: Regardless of the technique applied for chemomechanical preparation, postoperative pain is a very relevant matter in endodontics. Objective: To evaluate postoperative pain after endodontic treatment of necrotic teeth submitted to large apical preparation (LAP) using oscillatory kinematics. MATERIAL AND METHODS: The sample included 60 asymptomatic necrotic teeth with or without apical radiolucency, and with normal periodontal status, referred for endodontic treatment. Following initial procedures, the position and approximate size of the apical constriction were determined by using an apex locator and K Flexofiles, respectively. The chemomechanical preparation was conducted using oscillatory kinematics and 2.5ml of 2.5% NaOCl at each file change to achieve LAP, and the filling was done with Tagger's hybrid technique and EndoFill sealer. Phone calls were made to all the patients at 24, 48 and 72 hours after treatment to request their classification of postoperative pain, and data were submitted to statistical analysis. RESULTS: Only 3 patients (5%) reported severe pain after 72 hours. Moderate pain was reported by 17, 9 and 1 patient after 24, 48 and 72 hours, respectively (P = 0.000). However, paired analyses showed a statistically significant difference only between 24 and 72 hours (P = 0.001), and 48 and 72 hours (P = 0.014). Age and tooth type did not influence the postoperative pain, regardless of time (P> 0.05). After 72 hours, women experienced significantly more pain than men (P = 0.012), and teeth without periradicular lesion were more sensitive that teeth with perirradicular lesion (P = 0.027). CONCLUSIONS: Acute or moderate postoperative pain was uncommon after endodontic treatment of necrotic teeth submitted to LAP using oscillatory kinematics. Key words:Endodontic treatment, oscillatory kinematics, postoperative pain, pulp necrosis.

Validation of 3d metric and superimposition tools in three software packages for the morphological comparison of laser scanned anterior dentition models / Validação de ferramentas tridimensionais de três softwares para mensuração e sobreposição tridimensional de modelos odontológicos visando à comparação morfológica

Introduction: Few studies succeeded on demonstrating that dentitions are unique. Methodological limitations may have influenced these outcomes. Objective: The present study aims to validate software packages for comparing human dentitions. Material and methods: A pool of 40 dental casts were laser scanned (XCAD 3D®, XCADCAM Technology®, São Paulo, Brazil) and implemented in Geomagic Studio® (GS) (3D Systems®, Rock Hill, USA), Cloud Compare® (CC) (Telecom Paris Tech® and EDF®, Paris, France), and Maestro 3D Ortho Studio® (MS) (AGE Solutions®, Pontedera, Italy) software packages to evaluate metric and superimposition tools. Results: Software performances did not significantly differ (p>0.05) considering cropping, landmarking and superimposition functions. GS was more precise for detecting identical models (p>0.05. Inter and intra examiner reproducibility reached optimal outcomes. Calibration was assured for software measuring tools and scanning process. Conclusion: Both GS and CC may be used for comparing 3D anterior dentitions. However, more practical and less operator-depending procedures are available in GS.

Introdução: Poucos estudos obtiveram êxito em demonstrar a unicidade da dentição humana. Falhas metodológicas podem ter influenciado os resultados destes estudos. Objetivo: O presente estudo objetivou validar ferramentas contidas em pacotes de software existentes para comparar dentições humanas. Material e método: Uma amostra de 40 modelos odontológicos digitalizados (XCAD 3D®, XCADCAM Technology®, São Paulo, Brazil) foi selecionada e analisada utilizando os seguintes softwares: Geomagic Studio® (GS) (3D Systems®, Rock Hill, USA), Cloud Compare® (CC) (Telecom Paris Tech® and EDF®, Paris, France), and Maestro 3D Ortho Studio® (MS) (AGE Solutions®, Pontedera, Italy). Resultados: Os softwares não apresentaram performances com diferença estatisticamente significante (p>0.05) considerando os procedimentos de recorte, colocação de pontos de referência (landmarks) e sobreposição de modelos. O software GS apresentou maior precisão para detectar modelos idênticos ((p>0.05). Testes intra e interexaminador resultaram em ótima concordância. Os softwares apresentaram ótima calibração de ferramentas métricas. Conclusão: Ambos os softwares GS e CC podem ser utilizados para comparar modelos odontológicos digitalizados. Contudo, performances mais práticas e independentes do operador podem ser alcançadas por meio do software GS.