Descoloração da coroa após obturação endodôntica com diferentes cimentos: estudo clínico / Crown discoloration after endodontic obturation with different cements: a clinical study

Objetivo: O objetivo do presente estudo foi avaliar clinicamente a descoloração da coroa dentária após obturação do canal radicular com diferentes cimentos endodônticos. Métodos: Trinta e dois dentes foram tratados endodonticamente e obturados com AH Plus (AHP), Endofill (END), MTA Fillapex (MTA) ou Sealer 26 (SEA), divididos em oito pacientes por grupo. O registro das cores foi realizado com um espectrofotômetro antes da intervenção (T0 ), aos 30 (T1 ) e aos 90 dias após a intervenção (T2 ). As avaliações foram feitas no centro da coroa dentária e a variação de cor (ΔE) foi calculada por meio da Commission International de l'Eclai- rage (CIE) L*a*b. Um operador, especialista em Endodontia, realizou os procedimentos clínicos. Os dados foram submetidos a medidas repetidas ANOVA e teste de Tukey (Δ=5%). Resultados: Não houve diferença estatisticamente significativa na variação de cores entre os cimentos (AHP ΔE=4,11; END ΔE = 6,34; SEA ΔE = 8,77 e MTA ΔE = 12,15), p>0,05. Porém, houve diferença entre os períodos analisados (T1ΔE= 5,65; T2 ΔE = 10,02). Conclusões: Dentro das limitações deste estudo, todos os cimentos endodônticos causaram alterações cromáticas clinicamente perceptíveis na coroa dentária. No entanto, o AH Plus promoveu menos alterações cromáticas na coroa dentária (AU).

Introduction: The aim of this study was to evaluate the crown discoloration after root canal filling with different endodontic cements clinically. Methods: Thirty-two teeth were endodontically treated and filled with AH Plus (AHP), Endofill (END), MTA Fillapex (MTA), or Sealer 26 (SEA), divided into eight patients per group. Color recording was performed with a spectrophotometer before the intervention (T0 ) and at 30 (T1 ) and 90 days post-intervention (T2 ). The evaluations were done in the center of the dental crown and color variation (ΔE) was calculated by means of the Commission International de IEclairage (CIE) L*a*b. The data were subjected to repeated measures ANOVA and Tukeys test (alpha=5%). Results: There was no statistically significant difference in color variation between the cements (AHP ΔE=4.11; END ΔE=6.34; SEA ΔE=8.77, and MTA ΔE=12.15), p>0.05. However, there was a difference between the periods tested (T1 ΔE=5.65; T2 ΔE=10.02). Conclusions: All tested endodontic cements altered the color of dental crowns (AU).

Effects of 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide on adhesion of posts in teeth obturated with different sealers

Abstract The aim of this study was to evaluate the effect of 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide (EDC) on bond strength of fiberglass posts in root canals obturated with different endodontic sealers. Seventy-eight mandibular premolars were obturated with three sealers (n=26): Endofill (END), AH Plus (AHP), and Endosequence BC Sealer (EBS). After preparation of the post space, two subgroups were formed according to the cementation of the posts (n=13): with EDC (EDC), and without EDC (control - CON). The specimens were submitted to a pull-out test, failure mode classification, and root canal surface evaluation by scanning electron microscopy after post displacement. Regarding the bond strength, a significant difference between the EDC and CON subgroups occurred only in the END (p=0.001). No difference was detected among the CON subgroups (p=0.339). However, among the EDC subgroups, AHP presented significantly higher values (END versus AHP: p=0.001; AHP versus EBS: p=0.016). Upon classification of failure modes, score 1 (≥ 50% of cement) was the most commonly observed, except for the END + EDC. Remains of endodontic sealers and resin cements were found in the cervical third, but without statistical difference (p=0.269), while in the middle third, difference occurred (p=0.004). In conclusion, EDC decreases bond strength when associated with END sealer, without changing the failure mode between the resin cement and fiberglass post. The best performance was observed when EDC was combined with AHP sealer.

Resumo O objetivo deste estudo foi avaliar o efeito da 1-etil-3- (3-dimetilaminopropil) carbodiimida (EDC) na resistência de união de pinos de fibra de vidro em canais radiculares obturados com diferentes cimentos endodônticos. Setenta e oito pré-molares inferiores foram obturados com três cimentos endodônticos (n=26): Endofill (END), AH Plus (AHP) e Endosequence BC Sealer (EBS). Após o preparo do espaço para pino, dois subgrupos formaram-se conforme a cimentação dos pinos (n=13): com EDC e sem EDC (controle - CON). Os espécimes foram submetidos ao teste pull-out, classificação do modo de falha e avaliação da superfície do canal radicular por microscopia eletrônica de varredura após o deslocamento. Quanto à força de resistência de união, uma diferença estatisticamente significativa ocorreu entre os subgrupos EDC e CON apenas no END (p=0,001). Não foi detectada diferença entre os subgrupos CON (p=0,339). Contudo, no subgrupo EDC, o AHP apresentou maiores valores (END versus AHP: p=0,001; AHP versus EBS: p=0,016). Acerca da classificação dos modos de falha, o escore 1 (≥50% de cimento) foi o mais comumente observado, exceto para END + EDC. Restos de cimentos endodônticos e cimentos resinosos foram encontrados no terço cervical, mas sem diferença estatística (p=0,269), enquanto no terço médio, houve diferença (p=0,004). Em conclusão, o EDC diminui a resistência de união quando associado ao cimento END, sem alterar o modo de falha entre o cimento resinoso e o pino de fibra de vidro. O melhor desempenho foi observado quanto o EDC foi usado com o cimento AHP.

Bond strength at the cement/dentin interface according to protocols for final irrigation of post space

Aim: The aim was to evaluate the bond strength at the cement/dentin interface in the post space, after specimens were treated with different final irrigation protocols, followed by cementation with a dual resin cement. Methods: Forty-eight extracted uniradicular human premolars were divided into four groups according to the irrigation (n = 12): control with distilled water; 2.5% sodium hypochlorite (NaOCl) + ethylenediaminetetraacetic acid (EDTA); 2.5% NaOCl + passive ultrasonic irrigation (PUI); and 2% chlorhexidine (CHX). The pull-out test was performed. The results were evaluated using ANOVA with Tukey's paired comparisons, with a significance of 5%. Results: When all groups were compared, significant difference occurred (p = 0.006), and in the paired comparison, NaOCl + PUI and CHX differed (p = 0.005). The CHX showed significantly higher adhesive defects between cement and dentin than other groups. Conclusions: The final irrigation protocol for cleaning after preparation for post space directly influences the bond strength at the cement/dentin interface

Long-term evaluation of crown and root discoloration induced by different endodontic sealers

Aim: To evaluate crown and root discoloration promoted by different endodontic sealers after root canal filling. Methods: Eighty bovine incisors were prepared and filled with: Endofill, Sealer 26, AH Plus, and MTA Fillapex. Color was recorded using a spectrophotometer before endodontic treatment (T0) and at 24 hours (T1), seven days (T2), 30 days (T3), and 90 days (T4) after treatment. Analyses were performed on the middle and cervical regions of the crown, and on the cervical third of the root, immediately below the cementoenamel junction. The color alterations (ΔE) were calculated using Commission International de I'Eclairage (CIE) L*a*b parameters, and data were analyzed by analysis of variance (ANOVA) and Tukey's test (p<0.05). Results: All sealers induced color alterations. Sealer 26 resulted in the smallest changes in color (E = 5.32). The other materials did not present statistical differences (AH Plus E = 6.98; MTA Fillapex E = 6.88; Endofill E = 6.41). Of the three regions analyzed, the largest discoloration was observed at the cervical third of the root (E=10.67). In terms of time, the largest ΔE values (E=7.72) were observed at T4. Color changes at T1 (E=5.88), T2 (E=6.10), and T3 (E=5.89) were statistically similar. Conclusions: All endodontic sealers promoted discoloration on the tooth crown and root

Effectiveness of different final irrigation techniques and placement of endodontic sealer into dentinal tubules

Abstract: The aim of this study was to compare two irrigation techniques and four devices for endodontic sealer placement into the dentinal tubules. Ninety-nine single-rooted human teeth were instrumented and allocated to either the control (CO) (n=11) or experimental groups according to the irrigation method: syringe and NaveTip needle (NT) (n=44), and EndoActivator (EA) (n=44). These groups were subdivided according to sealer placement into K-File (KF), lentulo spiral (LS), Easy Clean (EC), and EndoActivator (EA) subgroups. Moreover, the distances of 5 mm and 2 mm from the apex were analyzed. The teeth were obturated with AH Plus and GuttaCore X3. Analyses were performed by scanning electron microscopy associated to cathodoluminescence. The percentage and maximum depth of sealer penetration were measured. Data were evaluated by three-way analysis of variance (ANOVA) and Games-Howell test (p<0.05). EA was superior to NT in percentage of sealer penetration. EC was significantly superior to EA (subgroup) for sealer penetration, and both improved the percentage of sealer penetration when compared to LS. Better sealer penetration was observed at the distance of 5 mm from the apex. Sealer penetration into the dentinal tubules was significantly improved by sonic irrigant activation.

Resistance and Stress Finite Element Analysis of Different Types of Fixation for Mandibular Orthognathic Surgery

Abstract The aim of this study was to evaluate the stress and dislodgement resistance by finite element analysis of different types of fixation in mandibular orthognathic surgery. A 3D solid finite element model of a hemi-mandible was obtained. A bilateral sagittal split osteotomy was simulated and the distal segment was advanced 5 mm forward. After the adjustment and superimposing of segments, 9 different types of osteosynthesis with 2.0 miniplates and screws were simulated: A, one 4-hole conventional straight miniplate; B, one 4-hole locking straight miniplate; C, one 4-hole conventional miniplate and one bicortical screw; D, one 4-hole locking miniplate and 1 bicortical screws; E, one 6-hole conventional straight miniplate; F, one 6-hole locking miniplate; G, two 4-hole conventional straight miniplates; H, two 4-hole locking straight miniplates; and I, 3 bicortical screws in an inverted-L pattern. In each model, forces simulating the masticatory muscles were applied. The values of stress in the plates and screws were checked. The dislodgement resistance was checked at the proximal segment since the distal segment was stable because of the screen at the occlusal tooth. The regions with the lowest and highest displacement were measured. The offset between the osteotomized segments was verified by millimeter intervals. Inverted-L with bicortical screws was the model that had the lowest dislodgment and the model with the lowest tension was the one with two conventional plates. The results suggest that the tension was better distributed in the locking miniplates, but the locking screws presented higher concentration of tension.

Resumo O objetivo deste estudo foi verificar o estresse e a resistência ao deslocamento, pela análise de elementos finitos, de diferentes tipos de fixação em cirurgia ortognática mandibular. Um modelo 3D de elementos finitos sólidos de uma hemi-mandíbula foi obtido. Uma osteotomia sagital bilateral foi simulada e o segmento distal foi avançado 5 mm. Após o ajuste e sobreposição dos segmentos, foram simulados 9 diferentes tipos de osteossíntese com miniplacas e parafusos 2.0: A, uma miniplaca reta convencional de 4 furos; B, uma miniplaca reta lock de 4 furos; C, uma miniplaca convencional de 4 furos e um parafuso bicortical; D, uma placa lock de 4 furos e 1 parafuso bicortical; E, uma miniplaca reta convencional de 6 furos; F, uma miniplaca lock de 6 furos; G, duas miniplacas retas convencionais de 4 furos; H, duas miniplacas lock de 4 furos; e I, três parafusos bicorticais em um padrão L invertido. Em cada modelo foram aplicadas forças simulando os músculos mastigatórios. Foram verificados os valores da tensão nas placas e parafusos. A resistência ao deslocamento foi verificada no segmento proximal, uma vez que o segmento distal era estável. Foi medida a região com o maior deslocamento inferior e superior. O deslocamento entre os segmentos osteotomizados foi verificado por intervalos milimétricos. Parafusos bicorticais em L invertido foram o modelo que teve o menor descolamento inferior, e o modelo com a tensão mais baixa foi o de duas placas convencionais. Os resultados sugerem que a tensão foi melhor distribuída nas miniplacas do tipo lock, mas os parafusos de fixação apresentaram maior concentração de tensão.

Performance of Three Single Instrument Systems in the Preparation of Long Oval Canals

Abstract This study aimed to evaluate the performance of the Wave One, Easy ProDesign Logic and One Shape systems in the preparation of long oval root canals. Forty-two mandibular incisors were randomized into three groups: Group I, Wave One Primary (WO) (#25.08); Group II, Easy ProDesign Logic (EPL) (#25.06) and Group III, One Shape (OS) (#25.06). Micro-computed tomography scans were obtained pre- and post-preparation of the samples. Instrument fractures or loss of working length did not occur in any of the groups. There was a statistically significant difference in total root canal volume between the WO and EPL (p<0.05) and OS systems (p<0.05) The mean percentages of instrumented canal area in the middle thirds were 76.9% in the WO, 62.3% in the EPL and 71.8% in the OS (p>0.05). The OS system had the strongest correlation between volume increase and instrumented area (R=0.63). The WO, EPL and OS systems presented mean preparation times of 2.13 min, 0.54 min, and 2.21 min (p<0.05), respectively. All three systems enabled the safe preparation of long oval root canals. The WO system most effectively increased root canal volume, but it did not affect the instrumented areas. The OS system had the strongest correlation between volume increase and instrumented area, while the EPL system was the fastest.

Resumo Este estudo teve como objetivo avaliar o desempenho dos sistemas Wave One, Easy ProDesign Logic e One Shape no preparo de canais radiculares ovais. Quarenta e dois incisivos inferiores foram randomizados em três grupos: Grupo I, Wave One primary (WO) (#25.08); Grupo II, Easy ProDesign Logic (EPL) (#25.06) e Grupo III, One Shape (OS) (#25.06). As amostras foram submetidas a microtomografia computadorizada antes e após o preparo. Não ocorreram fraturas de instrumento ou perda de comprimento de trabalho em qualquer dos três grupos. Houve diferença estatisticamente significante no volume total do canal radicular entre o WO e EPL. A média do percentual de área instrumentada do canal no terço médio foi 76,9% no grupo WO, 62,3% no grupo EPL e 71,8% no grupo OS (p>0,05). O sistema OS teve a correlação mais forte entre o aumento de volume e área instrumentada (R=0,63). Os sistemas WO, EPL e OS apresentaram tempos de preparo médios de 2,13 min, 0,54 min e 2,21 min (p<0,05). Todos os três sistemas foram seguros no preparo canais radiculares ovais. O sistema WO foi mais eficaz no aumento do volume de canal, entretanto, isso não afetou as áreas instrumentadas. O sistema OS teve a correlação mais forte entre o aumento de volume e área instrumentada, enquanto o sistema EPL foi o mais rápido.

Epidemiological data and relevance of care provided in dental emergency service of a private hospital

Introduction and Objective: The aims of this study were to determine the etiology and prevalence of dental emergency visits in a private hospital in the period from July 2009 to July 2011 and the importance of this type of service in private hospitals. Material and methods: During the study period, we analyzed 795 charts from patients seeking emergency services. The emergencies were classified as trauma, odontalgia, prosthesis, periodontal diseases, and traumatic factors. Results: Women and men accounted for 61% and 39% of cases, respectively, and the most prevalent age group was individuals aged 20 to 49 years. The predominant types of dental emergencies observed were odontalgia (52.58%) and dental trauma (22.64%). Pulpitis was the most common pathology (67% of cases) and the most frequent type of trauma was enamel and dentin fracture (54% of cases). Conclusion: A high demand for dental emergency care exists in hospital settings. Most people seek emergency dental services for emergencies related to lack of prevention and dental traumas.

Comparative analysis of four cleaning methods of endodontic files

Introduction: Due to the size and design of endodontic files, these instruments have been considered one of the most difficult to clean among all dental instruments. The debris maintenance within the sulcus prevents the effective sterilization and may compromise the disinfection of root canal systems in endodontic therapy. However, there is neither a method nor technique that standardized the cleaning of these instruments. Objective: To evaluate the cleaning ability of four techniques used in dentistry. Material and methods: For this purpose, 30 new size #40 Flexofile were used for the preparation of the canals of mandibular molars of pigs. After instrumentation, the contamination and the presence of debris in the sulcus was confirmed and the files were randomly divided into four groups: control group (without cleaning), group 1 (enzymatic detergent + manual brushing with nylon bristle brush), group 2 (ultrasound + enzymatic detergent), group 3 (ultrasound + water) and group 4 (gauze embedded in 70% alcohol). Next, all files were photographed and photographs were printed at high quality. The spirals containing debris were counted. Results: Manual cleaning with enzymatic detergent and nylon bristle brush, ultrasound with either water or detergent showed the best cleaning capacity in which respectively 100%, 98.9% and 96.2%, of the spirals were free of debris. Cleaning with alcohol and gauze proved to be ineffective, showing debris in more than 40% of the spirals by visual analysis. In control group, 91% of the spirals presented debris. It can be concluded that the association between manual and ultrasound cleaning may be promising in ensuring a cleaning protocol for endodontic files cleaning.

Bacterial infiltration comparison of two root canal filling techniques

Introduction: Root canal system filling aims to the hermetic sealing of the space formerly occupied by the dental pulp. Objective: The aim of this study was to analyze the bacterial infiltration of Enterococcus faecalis in root canals filled through two techniques: single cone technique (group A) and thermoplasticized gutta-percha technique (group B). Material and methods: A total of 40 single-rooted human premolars were divided into two experimental groups (n = 15) and two control groups: positive (n = 5) and negative (n = 5). The root canals were prepared with ProTaper Universal system up to size F3 file and filled with the corresponding gutta-percha point. Teeth were mounted on a dual-chamber model, where the infiltration of E. faecalis was evaluated for a 30-day period by BHI turbidity indicating bacterial growth. Results: After the trial period all specimens in experimental and positive control groups showed turbidity of the culture medium. The average number of days until culture medium turbidity was 11.42 days for group A, 16.69 days for group B, and 5.5 days for positive control. By applying Anova test, there was no statistically significant difference between groups (p > 0.05). This allowed the observation that no difference between the obturation techniques in the infiltration of E. faecalis could be observed by the methodology used. Conclusion: It can be concluded that regardless of the obturation techniques, bacterial infiltration occurred.

Adhesion and formation of tags from MTA Fillapex compared with AH Plus® cement

Introduction and Objective: The aim of this study was two-fold: 1) to evaluate, in vitro, the shear bond strength of two sealers by push-out test and 2) to assess the failures after displacement. Additionally, the formation of tags was observed by SEM. Material and methods: Forty mandibular premolars were selected and the canals were subjected to biomechanical preparation with rotary instruments. These specimens were divided into two groups according to the sealer (n = 20): GI - MTA Fillapex and GII - AH Plus. All roots were filled with sealer only, without gutta-percha. After a period corresponding to three times the setting time of the sealer, the roots were sectioned transversely into slices of 1 mm thickness, to obtain one slice from the cervical third, to be used in the push-out test. Following, two slices of each group were randomly chosen for ultrastructural analysis by scanning electron microscopy (SEM). The data obtained in shear bond strength test were subjected to statistical analysis. Results: AH Plus cement exhibited higher shear bond strength values (1.332±0.75 MPa) than MTA Fillapex (0.071±0.07 MPa), with statistically significant differences. Conclusion: MTA Fillapex has a low bond strength with less formation of tags than AH Plus.

The relationship of a clinical protocol and emergency treatment success of dental trauma running head: clinical protocol in dental trauma

Introduction and Objective: The aim of this study was to investigate whether the sequelae arising from dental trauma in permanent teeth were influenced by the use or non-use of a clinical protocol, in emergency care treatment facilities in the city of Joinville/SC, Brazil. Material and methods: From 2008 to 2010, a total of 70 dental records were reviewed and evaluated 6 months after the completion of treatment. In addition to the data relating to gender, age, etiology, most affected teeth, and most prevalent traumas, the individuals were divided into 2 groups to compare the sequelae observed following either the use or non-use of a clinical protocol for dental trauma treatment. Results: There was a greater incidence of male patients, particularly in the age-range of 8 to 15 years. Falls were the most frequent cause of trauma. The total success rate of the emergency care was of 78.57%. In the group in which the protocol was used, the success rate reached 88.89% compared to 60.0% in the group in which the protocol was not used. Conclusion: The use of a clinical protocol positively influenced the sequelae arising after treatment for dental trauma.

Classification of bifid mandibular canals using cone beam computed tomography

The objective of this study was to classify the morphology of bifid mandibular canals and to evaluate their relationship with the roots of third molars, using cone beam computed tomography (CBCT) scans. The CBCT scans of 75 patients were analyzed and the bifurcations were classified according to Langlais et al. (1985). The relationship of bifurcation and third molars was established according to the following classification: class A - uninvolved, class B - close relationship, class C - intimate relationship and class D - absence of third molars. Data were submitted to descriptive statistics, and the results indicated that the patients' mean age was 48.2 (± 13.2) years. Unilateral bifurcation (Type 1) was the most frequent type (72.6%), followed by unilateral Type 2 (19.3%). Class D was the most frequent (57.33%), followed by class C (21.33%), class B (13.33%) and class A (8%). It could be concluded that most cases presented unilateral bifid mandibular canals extending to the third molar or adjacent regions, and when present, the roots seemed to be a continuation of the bifid mandibular canal.

Effect of water storage and hydrophobic adhesive layer application on the bond strength of allll-in-one adhesives

Introduction: To prevent the rate of water absorption and degradation of exposed collagen and the resin matrix on the hybrid layers, the use of an additional layer of hydrophobic resin on all-in-one adhesives is one of the approaches to improve the bond strength and infiltration of monomers in demineralized dentin. Objectives: To compare the microshear bond strength of different self-etching adhesive systems, and to evaluate the effect of the application of a hydrophobic adhesive layer on all-in-one adhesive systems after a storage period of 48 h and 30 days in distilled water at 37oC. Material and methods: Bovine incisor crowns were polished to expose flat dentin surfaces. The crowns were randomly distributed into 14 groups (n = 12) according to the adhesive system [Clearfil SE Bond (CSEB), AdheSE (ASE), Adper Scotchbond SE (SSE), Adper Easy Bond (EB), and Go! (GO)], and storage time. In two groups (indicated as GO+B and EB+B), a layer of a hydrophobic adhesive was applied on all-in-one adhesive systems. After 48h and 30 days of storage in distilled water at 37oC, microshear bond strength was determined. The data were statistically analyzed by ANOVA and Tukey's test (α = 5%). Results: After 48h, EB, EB+B, CSEB, and GO+B showed higher bond strength values. The application of a hydrophobic layer did not influence EB and increased GO bond strength values. After 30 days, CSEB, SSE, and EB+B showed the highest bond strength values. Comparing groups of all-in-one adhesives with and without a hydrophobic adhesive-resin layer, the bond strength values showed no significant difference. Conclusion: The application of a hydrophobic adhesive-resin layer increased bond strength values only at 48h. With respect to bond degradation over time, only EB showed a statistically significant decrease of bond strength after 30 days.

Apicoectomy after conventional endodontic treatment failure: case report

Introduction: Paraendodontic surgery is a safe and adequate alternative when teeth are not responding to conventional treatment and endodontic re-treatment. It must only be applied in specific situations. Endodontic treatment failures can be related to: extraradicular infections such as periapical actinomycosis; to foreign body reactions that can be caused by endodontic material extrusion; to endogenous cholesterol crystal accumulation in apical tissues; and unresolved cystic lesion. Paraendodontic surgery comprehends a set of procedures recommended in periapical diseases treatment, when traditional endodontic therapy does not obtain favorable outcomes. Objective: To report a clinical case where an apicoectomy was indicated due to failure in conventional endodontic treatment. Case report and Conclusion: Clinical case report of a tooth with unsatisfying conventional endodontic treatment history, due to lack of treatment in fourth root canal and an unsuccessful apicoectomy, since the lesion and the fistula had persisted. It was chosen to retreat tooth #26 and perform a new apicoectomy in the mesiobuccal root. The treatment was successful due to absence of fistula and painful symptoms and due to periapical bone repair.

Performance of RaCe Instrumentation System in Curved Root Canals: A Comprehensive Analysis by Three Study Methods

In this study, curved maxillary molar root canals were instrumented with RaCe rotary system to evaluate: 1. the occurrence of canal transportation using a radiographic platform; 2. the action of the instruments on the dentin walls, centering ability and canal enlargement by analysis of digital images; and the percentage of regular dentin surfaces and debris within the canal by histological analysis. Ten mesiobuccal roots of extracted human maxillary molars were embedded in acrylic resin and sectioned at the middle and apical thirds. Root canal shaping was performed using the RaCe rotary system at 250 rpm and 1 Ncm torque. Each instrument set was used five times according to a crown-down technique in the following sequence: 40/0.10, 35/0.08, 25/0.06, 25/0.04, 25/0.02 (working length - WL), 30/0.02 (WL) and 35/0.02 (WL). Each instrument was inserted until resistance was felt and then pulled back, followed by brushing movements towards all canal walls. Each specimen was assessed by three study methods: radiographic platform, digitized image assessment and histological analysis. The radiographic platform showed lack of apical transportation. No statistically significant difference (Wilcoxon test, p>0.05) was found between the middle and apical thirds regarding instrument action on dentin walls, centering ability, area of root canal enlargement, percentage of regular dentin surfaces and debris within the root canal. It may be concluded that RaCe system is a suitable method for the preparation of curved root canals, regarding the maintenance of root canal original path, action on dentin walls, canal enlargement and removal of debris from the root canal lumen.

O objetivo do presente estudo foi verificar a presença de desvio apical por meio da plataforma radiográfica, avaliar a ação dos instrumentos, centralização do preparo e ampliação por meio de imagens digitais do canal e calcular a porcentagem de superfícies regulares e presença de debris por meio da análise histológica. Dez raízes mésiovestibulares de molares superiores extraídos foram incluídos em blocos de resina e seccionados no terço médio e apical. O preparo do canal foi feito empregando o sistema RaCe, a 250 rpm e torque de 1 Ncm. Cada sistema rotatório foi usado 5 vezes no sentido coroa-ápice na seguinte sequência: 40/0.10, 35/0.08, 25/0.06, 25/0.04, 25/0.02 (comprimento de trabalho - CT), 30/0/02 (CT) e 35/0/02 (CT). Cada amostra foi avaliada por 3 métodos de estudo: plataforma radiográfica, imagem digital e análise histológica. A plataforma radiográfica mostrou ausência de transporte apical. Em relação à ação dos instrumentos sobre as paredes dentinárias, centralização do preparo, ampliação, porcentagem de superfícies regulares e presença de debris, o teste estatístico de Wilcoxon não mostrou diferença significativa entre os terços apical e médio. O sistema RaCe se mostrou adequado para o preparo de canais radiculares curvos em relação à manutenção do trajeto original do canal, ação sobre as paredes dentinárias, ampliação e remoção de debris da luz do canal radicular.

The challenges of treating a fused tooth

This paper describes and discusses the multidisciplinary treatment involving a permanent maxillary lateral incisor fused to a supernumerary tooth, both presenting pulp necrosis and periapical lesion. A 15-year-old male patient sought treatment complaining of pain, swelling and mobility on the maxillary right lateral incisor. After clinical and radiographic examination, root canal preparation was performed according to the crown-down technique and a calcium hydroxide dressing was placed for 15 days. The patient returned and the definitive endodontic filling was done with thermomechanical compaction of gutta-percha and sealer. After 18 months, clinical and radiographic examinations were carried out and no pain or swelling was reported. Two years after endodontic treatment, the patient returned for periodontal and cosmetic treatments. Nine months later, a cone-beam computed tomography (CBCT) revealed that the previously detected periodontal defect and periapical lesion were persistent. Apical endodontic surgery was indicated. The supernumerary tooth was removed, the communicating distal surface was filled and the surgical site received bioactive glass and demineralized bovine organic bone. The pathological tissue was submitted to histopathological examination and the diagnosis was periapical cyst. One year after the apical endodontic surgery, CBCT showed bone formation at maxillary lateral incisor apical area. Two years after the surgery, the restoration was replaced due to aesthetic reasons and periapical radiograph showed success after 5 years of treatment. A correct diagnosis and establishment of an adequate treatment plan resulted in a successful management of the case.

Este caso descreve o tratamento multidisciplinar de um incisivo lateral superior permanente fusionado a um dente supranumerário, ambos apresentando necrose pulpar e lesão periapical. Paciente compareceu ao consultório se queixando de dor, edema e mobilidade do incisivo lateral superior. O preparo endodôntico foi realizado no sentido coroa-ápice e foi colocada pasta de hidróxido de cálcio como medicação intra-canal por 15 dias. A seguir, a obturação foi realizada pela termoplastificação da guta-percha. Após 18 meses, foram realizados exames clínicos e radiográficos indicando ausência de dor e edema. Dois anos após o tratamento endodôntico, o paciente retornou para o tratamento periodontal e estético. Nove meses depois, foi realizada tomografia computadorizada e observou-se presença de defeito periodontal e lesão periapical. Foi então indicada e planejada a cirurgia paraendodôntica. O dente supranumerário foi removido e a área de comunicação com o canal radicular do incisivo lateral foi preenchida; a loja cirúrgica foi preenchida com vidro bioativo e osso orgânico bovino desmineralizado. O tecido patológico da lesão periapical foi submetido à análise histopatológica sendo diagnosticado como cisto periapical. Um ano após a cirurgia parendodôntica, uma nova tomografia computadorizada mostrou neoformação óssea na região periapical do dente em questão. Doi anos após a cirurgia, a restauração foi trocada devido à motivos estéticos e uma radiografia periapical mostrou sucesso do tratamento (5 anos após o tratamento inicial). Um correto diagnóstico e plano de tratamento multidisciplinar é essencial para o sucesso do tratamento de dentes fusionados à dentes supranumerários.

Aplicação de membrana experimental de PTFE em defeito cirúrgico periodontal de ratos / Experimental PTFE membrane in a surgically periodontal defect in rats

Objetivo - Avaliar a influência do uso de membrana alternativa de PTFE (politetrafluoretileno) na regeneração tecidual guiada em defeitos periodontais de ratos. Métodos - Foram utilizados 20 ratos, machos, divididos em grupos controle e teste. Foi criado um defeito ósseo em mandíbula no periodonto de suporte do incisivo inferior direito. O grupo teste recebeu a membrana de PTFE; o grupo controle foi preenchido por coágulo. Os resultados foram avaliados por microscopia de luz e microscopia eletrônica de varredura, aos 7 e 21 dias. Resultados - Ocorreu neoformação óssea parcial em todos os casos analisados; no grupo teste ocorreu separação entre a membrana e os tecidos circundantes, e houve diferença no sentido tanto das fibras colágenas quanto da deposição óssea. Conclusão - A membrana experimental de teflon foi eficaz como barreira física e separou o ambiente do defeito da mucosa e submucosa; no entanto, alterou a biologia do reparo, mudando o padrão de deposição de matriz óssea em relação à fisiologia normal.

Objective - To assess the influence of an experimental PTFE membrane in guided tissue regeneration in rats. Methods - Twenty male rats were divided in control and test groups. A surgical defect was created in the mandible, at the periodontium of the right lower incisor. The test group received the PTFE membrane and in the control group the defect was filled with blood clot. The results were assessed by light microscopy and scanning electron microscopy at 7 and 21 days. Results - Partial bone neoformation was shown in all cases; in the test group it did not joined the surrounding tissues. There was a microscopic difference between the groups regarding the direction of the collagen fibersand osseous neoformation. Conclusion - The experimental PTFE membrane worked efficiently as a physical barrier, separating the defect environment from the mucosa and submucosa; however it changed the repair biology and the pattern of bone matrix deposition in relation to the normal physiology.