Effect of access design on intracoronal bleaching of endodontically treated teeth: An ex vivo study.

OBJECTIVES: To determine the effect of access design on intracoronal bleaching with 35% carbamide peroxide on discolored teeth. MATERIALS AND METHODS: Forty-two intact maxillary central incisors were selected, sectioned and artificially stained using whole blood. Color measurements were performed with a spectrophotometer: before staining (T1), after staining (T2), at 7 (T3), and 14 (T4) days postbleaching. After T1, specimens were stratified and divided randomly into two groups according to access design (N = 20): G1: contracted endodontic cavity (CEC) access performed with a #848-010M bur and G2: traditional endodontic cavity (TEC) access done with a #1157 bur. Canals were obturated, a cervical barrier was placed and 35% carbamide peroxide was sealed in the chamber for 7 days and replaced at 7 days for an additional 7 days. Data were collected based on CIELAB-CIE1976 (L* a* b* ) system. Repeated measures SNK anova was used to evaluate the effects of access design and time on color change (ΔE* ) and luminosity (L* ) (α < 0.05). RESULTS: For CEC, L* was significantly different at all times points (P < .05). For TEC, L* values were significantly different at all time points (P < .05) except for T0 and T4, which were similar (P > .05). There was no statistical difference for ΔE* between CEC and TEC designs at any time point (P > .05). CONCLUSIONS: In general, teeth accessed with CEC or TEC designs showed statistically similar bleaching when using 35% carbamide peroxide. However, lightness values were only reestablished with bleaching through a TEC access design. CLINICAL SIGNIFICANCE: Despite the current trend to conserve tooth structure when performing endodontic access cavities, the use of conservative access designs for bleaching discolored maxillary central incisors affected the acceptability threshold when compared with a traditional access design. These smaller accesses might not be an alternative treatment option when internal bleaching in the esthetic zone is anticipated.

Removal of calcium hydroxide from Weine Type II systems using photon-induced photoacoustic streaming, passive ultrasonic, and needle irrigation: a microcomputed tomography study

ABSTRACT Objective This study compared the effectiveness of Er:YAG laser-activated irrigation (PIPS), passive ultrasonic irrigation (PUI) with EndoUltra and standard needle irrigation (SNI) in the removal of calcium hydroxide [Ca(OH)2] from the mesial roots of Weine Type II mandibular molars. Material and Methods Thirty mandibular molars were screened by µCT for the presence of mesial roots with complex intra-canal anatomy and a common apical foramen. The teeth were enlarged to a standardized 25/.06 preparation and filled with Ca(OH)2 paste. Specimens were divided into three groups (n=10) according to the technique used for Ca(OH)2 removal: PIPS, at 15 Hz and 20 mJ using a 9 mm long, 600 µm diameter tip; PUI using a 15/.02 tip; and SNI (30 Ga. side-vented needle). Equal volumes of 8.25% NaOCl and 17% EDTA were used in all groups. µCT was used to measure the initial amount of Ca(OH)2 present and to assess the residual volume of Ca(OH)2 following each irrigation protocol. Data were analyzed using Tukey HSD and Kruskal-Wallis tests (α=5%). Results The mean volume of Ca(OH)2 before removal was significantly higher in the coronal third than in the middle and apical third (p<0.001). Ca(OH)2 was similarly removed from the coronal and middle thirds with the three methods used (p>0.05). PIPS (median 0%; IQR: 0-0) showed significant higher Ca(OH)2 removal in the apical third than PUI (median 100%, IQR: 85-100) and SNI (median 47%; IQR: 16-72) (p<0.001). Conclusions PIPS laser-activation was more effective for the removal of Ca(OH)2 from mesial roots of mandibular molars with Weine Type II canal configurations than PUI with EndoUltra and SNI.

Removal of calcium hydroxide from Weine Type II systems using photon-induced photoacoustic streaming, passive ultrasonic, and needle irrigation: a microcomputed tomography study.

OBJECTIVE: This study compared the effectiveness of Er:YAG laser-activated irrigation (PIPS), passive ultrasonic irrigation (PUI) with EndoUltra and standard needle irrigation (SNI) in the removal of calcium hydroxide [Ca(OH)2] from the mesial roots of Weine Type II mandibular molars. MATERIAL AND METHODS: Thirty mandibular molars were screened by µCT for the presence of mesial roots with complex intra-canal anatomy and a common apical foramen. The teeth were enlarged to a standardized 25/.06 preparation and filled with Ca(OH)2 paste. Specimens were divided into three groups (n=10) according to the technique used for Ca(OH)2 removal: PIPS, at 15 Hz and 20 mJ using a 9 mm long, 600 µm diameter tip; PUI using a 15/.02 tip; and SNI (30 Ga. side-vented needle). Equal volumes of 8.25% NaOCl and 17% EDTA were used in all groups. µCT was used to measure the initial amount of Ca(OH)2 present and to assess the residual volume of Ca(OH)2 following each irrigation protocol. Data were analyzed using Tukey HSD and Kruskal-Wallis tests (α=5%). RESULTS: The mean volume of Ca(OH)2 before removal was significantly higher in the coronal third than in the middle and apical third (p<0.001). Ca(OH)2 was similarly removed from the coronal and middle thirds with the three methods used (p>0.05). PIPS (median 0%; IQR: 0-0) showed significant higher Ca(OH)2 removal in the apical third than PUI (median 100%, IQR: 85-100) and SNI (median 47%; IQR: 16-72) (p<0.001). CONCLUSIONS: PIPS laser-activation was more effective for the removal of Ca(OH)2 from mesial roots of mandibular molars with Weine Type II canal configurations than PUI with EndoUltra and SNI.

Influence of Hero Apical instruments on cleaning ovoid-shaped root canals.

The cleaning capacity of Hero 642 nickel-titanium files, complemented by the Hero Apical instruments in flattened roots, was determined by histological analysis, considering the area of action of the instruments on the coronal walls and the presence of remaining debris. Twenty-four single-canal, human mandibular incisors were divided into three groups and prepared as follows: GI, instrumented with Hero 642 NiTi files 30/.06, 25/.06, 20/.06, 25/.06, and 30/.06; GII, instrumented as GI followed by Hero Apical size 30/.06; GIII, instrumented as GI followed by Hero Apical sizes 30/.06 and 30/.08, then returning to 30/.06 with pendulum movements. The apical thirds were prepared for histological processing, analyzed at 40× magnification and the images were examined morphometrically. Statistical analysis showed that GIII presented the best results for removing debris (5.22% ± 4.13), with more contact between the instruments and the root canal walls (19.31% ± 0.15). This differed statistically from GI (14.04% ± 4.96 debris removal, with 42.96% ± 7.11 instrument contact) and GII (12.62% ± 5.76 debris removal, with 35.01% ± 0.15 instrument contact). Root canal preparation with Hero 642, complemented by Hero Apical instruments (30/.06 and 30/.08, then re-instrumented with Hero Apical 30/.06 using pendulum movements), was more efficient for debris removal and allowed more contact of the instruments with the root canal walls. GII presented the worst results.

Influence of Hero Apical instruments on cleaning ovoid-shaped root canals

The cleaning capacity of Hero 642 nickel-titanium files, complemented by the Hero Apical instruments in flattened roots, was determined by histological analysis, considering the area of action of the instruments on the coronal walls and the presence of remaining debris. Twenty-four single-canal, human mandibular incisors were divided into three groups and prepared as follows: GI, instrumented with Hero 642 NiTi files 30/.06, 25/.06, 20/.06, 25/.06, and 30/.06; GII, instrumented as GI followed by Hero Apical size 30/.06; GIII, instrumented as GI followed by Hero Apical sizes 30/.06 and 30/.08, then returning to 30/.06 with pendulum movements. The apical thirds were prepared for histological processing, analyzed at 40× magnification and the images were examined morphometrically. Statistical analysis showed that GIII presented the best results for removing debris (5.22 percent ± 4.13), with more contact between the instruments and the root canal walls (19.31 percent ± 0.15). This differed statistically from GI (14.04 percent ± 4.96 debris removal, with 42.96 percent ± 7.11 instrument contact) and GII (12.62 percent ± 5.76 debris removal, with 35.01 percent ± 0.15 instrument contact). Root canal preparation with Hero 642, complemented by Hero Apical instruments (30/.06 and 30/.08, then re-instrumented with Hero Apical 30/.06 using pendulum movements), was more efficient for debris removal and allowed more contact of the instruments with the root canal walls. GII presented the worst results.

Ultra-structural changes at the apical stop irradiated with CO2 laser.

OBJECTIVE: This study evaluated ultra-structural dentine changes at the apical stop after CO(2) laser irradiation used during biomechanical preparation. BACKGROUND: Most studies evaluating the sealing efficiency of CO(2) lasers have been carried out after apical root canal resections and retro-filling procedures. METHODS: Sixty human canines were prepared with #1 to #6 Largo burs. The apical stops were established at 1 mm (n = 30) and 2 mm (n = 30) from the apex. Final irrigation was performed with 1% NaOCl and 15% EDTA followed by 20 ml of distilled and deionized water. Specimens were subdivided into three subgroups (n = 10 for each stop distance): GI- no radiation (n = 20); GII- 3W potency (n = 20), GIII- 5W potency (n = 20). After preparation, specimens were evaluated by scanning electron microscopy, with ultra-structural changes classified according to a scoring system based on six qualitatively different outcomes. RESULTS: Statistical analysis using the Mann-Whitney test confirmed more intense results for the specimens irradiated at 5 W potency than at 3 W (p < 0.0001). The Kruskal-Wallis test indicated that when using the same potencies (3 or 5 W) at 1 and 2 mm from the apex, there were no statistically significant differences in ultra-structural changes. CONCLUSIONS: Our results showed that ultra-structural changes ranged from smear layer removal to dentine fusion. As laser potency was increased from 3 to 5 W, ultra-structural changes included extensive fused lava-like areas sealing the apical foramen.

Dentin permeability of the apical third in different groups of teeth.

This ex vivo study evaluated dentin permeability of the root canal in the apical third of different human groups of teeth. Eighty teeth were used, 8 from each dental group: maxillary and mandibular central incisors, lateral incisors and canines, maxillary first premolars (buccal and palatal roots), mandibular first premolars, and maxillary and mandibular second premolars, totalizing 88 roots that were distributed in 11 groups. The root canals were instrumented, irrigated with 1% NaOCl and 15% EDTA. Roots were immersed in 10% copper sulfate for 30 min and then in 1% rubeanic acid alcohol solution for the same period; this chemical reaction reveals dentin permeability by the formation of copper rubeanate, which is a dark-colored compound. Semi-serial 100-µm-thick cross-sections were obtained from the apical third of the roots. Five sections of each apical third were washed, dehydrated, cleared and mounted on glass slides for examination under optical microscopy. The percentage of copper ion infiltration and the amount of tubular dentin were quantified by morphometric analysis. The penetration of copper ions in the apical third ranged from 4.60 to 16.66%. The mandibular central and lateral incisors presented the highest dentin permeability (16.66%), while the maxillary canines and mandibular second and first premolars presented the lowest dentin permeability (4.60%, 4.80% and 5.71%, respectively; p<0.001). The other teeth presented intermediate permeability. In conclusion, dye penetration into dentin tubules at the apical region is strongly dependent on the group of teeth evaluated.

Dentin permeability of the apical third in different groups of teeth

This ex vivo study evaluated dentin permeability of the root canal in the apical third of different human groups of teeth. Eighty teeth were used, 8 from each dental group: maxillary and mandibular central incisors, lateral incisors and canines, maxillary first premolars (buccal and palatal roots), mandibular first premolars, and maxillary and mandibular second premolars, totalizing 88 roots that were distributed in 11 groups. The root canals were instrumented, irrigated with 1 percent NaOCl and 15 percent EDTA. Roots were immersed in 10 percent copper sulfate for 30 min and then in 1 percent rubeanic acid alcohol solution for the same period; this chemical reaction reveals dentin permeability by the formation of copper rubeanate, which is a dark-colored compound. Semi-serial 100-µm-thick cross-sections were obtained from the apical third of the roots. Five sections of each apical third were washed, dehydrated, cleared and mounted on glass slides for examination under optical microscopy. The percentage of copper ion infiltration and the amount of tubular dentin were quantified by morphometric analysis. The penetration of copper ions in the apical third ranged from 4.60 to 16.66 percent. The mandibular central and lateral incisors presented the highest dentin permeability (16.66 percent), while the maxillary canines and mandibular second and first premolars presented the lowest dentin permeability (4.60 percent, 4.80 percent and 5.71 percent, respectively; p<0.001). The other teeth presented intermediate permeability. In conclusion, dye penetration into dentin tubules at the apical region is strongly dependent on the group of teeth evaluated.

Este estudo ex vivo avaliou a permeabilidade da dentina do canal radicular do terço apical de diferentes grupos de dentes humanos. Foram utilizados 80 dentes, sendo 8 de cada grupo dental superior e inferior: incisivos centrais, incisivos laterais, caninos, primeiros pré-molares superiores (raízes vestibulares e palatinas), primeiros pré-molares inferiores, segundos pré-molares superiores e inferiores, totalizando 88 raízes, as quais foram distribuídas em 11 grupos. Os canais foram instrumentados, irrigados com NaOCl a 1 por cento e EDTA a 15 por cento. As raízes foram imersas em sulfato de cobre a 10 por cento por 30 min e acido rubeânico a 1 por cento pelo mesmo período. Esta reação química revela a permeabilidade da dentina por meio da formação de um complexo escurecido denominado rubeanato de cobre. Hemi-secções de 100 µm de espessura foram obtidas do terço apical da raiz. Cinco secções do terço apical foram lavadas, desidratadas, diafanizadas e montadas em lâminas para análise em microscopia óptica. A porcentagem de infiltração de íons cobre e a quantidade de dentina tubular foram quantificadas por meio de análise morfométrica. A penetração de íons cobre no terço apical da raiz variou de 4,60 por cento a 16,66 por cento. Os incisivos centrais e laterais apresentaram a maior permeabilidade dentinária (16,66 por cento), e os caninos superiores e segundos e primeiros pré-molares inferiores as menores (4,60 por cento, 4,80 por cento e 5,71 por cento, respectivamente; p<0,001). Os outros dentes apresentaram permeabilidade intermediaria. Conclui-se que a penetração de corante nos túbulos dentinários da região apical é extremamente dependente do grupo de dentes avaliado.

Permeability of different groups of maxillary teeth after 38% hydrogen peroxide internal bleaching.

This study evaluated the influence of internal tooth bleaching with 38% hydrogen peroxide (H2O2) on the permeability of the coronal dentin in maxillary anterior teeth and premolars. Seventy teeth (14 per group) were used: central incisors (CI), lateral incisor (LI), canines (C), first premolars (1PM) and second premolars (2PM). Pulp chamber access and transversal sectioning at 2 mm from the cementoenamel junction were performed and the specimens were divided into 2 groups (n= 7): a) no treatment and b) bleaching with 38% H2O2. The bleaching agent was applied to the buccal surface and to the pulp chamber for 10 min. This procedure was repeated 3 times. The specimens were processed histochemically with copper sulfate and rubeanic acid, sectioned longitudinally, and digitalized in a scanner. The area of stained dentin was measured using Image Tool software. Data were analyzed statistically by ANOVA and Tukey's HSD test (alpha=0.05). There was statistically significant difference (p<0.001) among the untreated groups, CI (0.23 +/- 0.26) having the lowest permeability and LI (10.14 +/- 1.89) the highest permeability. Among the bleached groups, dentin permeability was increased in all groups of teeth except for 2PM. It may be concluded that bleaching with 38% H2O2 affected dentin permeability near the pulp chamber in maxillary anterior teeth and in first and second premolars.

Permeability of different groups of maxillary teeth after 38 percent hydrogen peroxide internal bleaching

This study evaluated the influence of internal tooth bleaching with 38 percent hydrogen peroxide (H2O2) on the permeability of the coronal dentin in maxillary anterior teeth and premolars. Seventy teeth (14 per group) were used: central incisors (CI), lateral incisor (LI), canines (C), first premolars (1PM) and second premolars (2PM). Pulp chamber access and transversal sectioning at 2 mm from the cementoenamel junction were performed and the specimens were divided into 2 groups (n= 7): a) no treatment and b) bleaching with 38 percent H2O2. The bleaching agent was applied to the buccal surface and to the pulp chamber for 10 min. This procedure was repeated 3 times. The specimens were processed histochemically with copper sulfate and rubeanic acid, sectioned longitudinally, and digitalized in a scanner. The area of stained dentin was measured using Image Tool software. Data were analyzed statistically by ANOVA and Tukey's HSD test (?=0.05). There was statistically significant difference (p<0.001) among the untreated groups, CI (0.23 ± 0.26) having the lowest permeability and LI (10.14 ± 1.89) the highest permeability. Among the bleached groups, dentin permeability was increased in all groups of teeth except for 2PM. It may be concluded that bleaching with 38 percent H2O2 affected dentin permeability near the pulp chamber in maxillary anterior teeth and in first and second premolars.

Este estudo avaliou a influência do clareamento interno com peróxido de hidrogênio (H2O2) a 38 por cento na permeabilidade da dentina coronária de dentes anteriores superiores e pré-molares superiores. Quatorze incisivos centrais (IC), incisivos laterais (IL), caninos (C), primeiros (1PM) e segundos (2PM) pré-molares foram seccionados transversalmente e distribuídos em 2 grupos (n=7) sendo: G1: não receberam tratamento e, G2: clareados com aplicação de gel na face vestibular e câmara pulpar por 10 min, repetido 3 vezes. Os espécimes foram processados histoquimicamente por meio de imersão em sulfato de cobre e ácido rubeânico e digitalizados em escaner. A área corada foi aferida (Programa Image Tool). Os dentes que não receberam tratamento, apresentaram diferença estatisticamente significante (p<0,001), sendo o ICS (0,23 ± 0,26) e o ILS (10,14 ± 1,89) os grupo com os menores e os maiores valores de permeabilidade, respectivamente. Quando clareados, a permeabilidade coronária dos grupos dentais foi aumentada, exceto no grupo do 2PM. Concluiu-se que a permeabilidade da dentina coronária nos dentes anteriores superiores e primeiros pré-molares foi alterada pelo clareamento dental interno.

Ultrastructural evaluation of radicular dentin after Nd:YAG laser irradiation combined with different chemical substances.

This aticle sought to evaluate the dentin morphology after irradiation by a Neodymium:Yttrium-Aluminum-Garnet (Nd:YAG) laser, using different chemical substances to irrigate radicular canals: distilled water, 17% ethylenediaminetetraacetic acid plus Cetavlon (EDTAC), 1% sodium hypochlorite, and 2% chlorhexidine. Groups were subdivided according to the protocol of laser application (n=9). The specimens were analyzed by scanning electron microscopy (SEM). No differences were found in dentin morphology when different root thirds were examined. Regardless of the chemical substance used, alterations were more evident in groups in which the surfaces were dried before laser irradiation. Fusion areas, craters, carbonization, and partially exposed tubules were verified. When the irradiation was performed in water, the smear layer was incorporated into the laser-modified surface. Among the specimens irrigated with EDTAC and laser-treated, partial obliteration of dentin tubules due to the laser action was verified; in addition, there was no remaining smear layer on the surfaces. Samples irrigated with sodium hypochlorite followed by laser irradiation demonstrated similar morphology to the samples in the chlorhexidine group, with some fusion areas present and no exposed dentin tubules or fissures. The irradiation from an Nd:YAG laser in the presence of EDTAC solution provided a more favorable surface pattern compared to the other experimental conditions, due to the removal of the contaminated layer and the posterior sealing of dentin tubules.

Coronal resistance to fracture of endodontically treated teeth submitted to light-activated bleaching.

OBJECTIVES: The aim of this study was to assess the fracture resistance of endodontically treated teeth submitted to bleaching with 38% hydrogen peroxide activated by light-emitting diode (LED)-laser system. METHODS: Fifty maxillary incisors were endodontically treated, received a zinc phosphate barrier and were embedded in acrylic resin until cemento-enamel junction. The specimens were distributed into five groups (n=10) according to the number of bleaching sessions: GI, no treatment (control); GII, one session; GIII, two sessions; GIV, three sessions and GV, four sessions. The whitening gel was applied to the buccal surface of the tooth and inside the pulp chamber for three times in each session, followed by LED-laser activation. Specimens were submitted to the fracture resistance test (kN) and data were submitted to the Tukey-Kramer multiple comparisons test. RESULTS: No significant difference (p>0.05) was found between GI (0.71+/-0.30) and GII (0.65+/-0.13), which presented the highest strength values to fracture. Groups III (0.35+/-0.17), IV (0.23+/-0.13) and V (0.38+/-0.15) showed lower resistance to fracture (p<0.01) when compared to GI and GII. CONCLUSIONS: The fracture resistance of endodontically treated teeth decreased after two sessions of bleaching with 38% hydrogen peroxide activated by LED-laser system.

Ultrastructural analysis of root canal dentine irradiated with 980-nm diode laser energy at different parameters.

OBJECTIVE: The purpose of this in vitro study was to investigate using the scanning electron microscope (SEM) the ultrastructural morphological changes of the radicular dentine surface after irradiation with 980-nm diode laser energy at different parameters and angles of incidence. BACKGROUND DATA: There have been limited reports on the effects of diode laser irradiation at 980 nm on radicular dentin morphology. MATERIALS AND METHODS: Seventy-two maxillary canines were sectioned and roots were biomechanically prepared using K3 rotary instruments. The teeth were irrigated with 2 mL of distilled water between files and final irrigation was performed with 10 mL of distilled water. The teeth were then randomly divided into five groups (n = 8 each) according to their diode laser parameters: Group 1: no irradiation (control); group 2: 1.5 W/continuous wave (CW) emission (the manufacturer's parameters); group 3: 1.5 W/100 Hz; group 4: 3 W/CW; and group 5: 3 W/100 Hz. Laser energy was applied with helicoid movements (parallel to the canal walls) for 20 sec. Eight additional teeth for each group were endodontically prepared and split longitudinally and irradiation was applied perpendicularly to the root surface. RESULTS: Statistical analysis showed no difference between the root canal thirds irradiated with the 980-nm diode laser, and similar results between the parameters 1.5 W/CW and 3 W/100 Hz (p > 0.05). CONCLUSION: When considering different output powers and delivery modes our results showed that changes varied from smear layer removal to dentine fusion.

Effectiveness of root canal debris removal using passive ultrasound irrigation with chlorhexidine digluconate or sodium hypochlorite individually or in combination as irrigants.

AIM: The aim of this in vitro study was to evaluate the cleaning capacity of different auxiliary chemical substances energized with ultrasound in radicular dentin using morphologic analysis. METHODS AND MATERIALS: Twenty-eight single-canal, mandibular incisors were prepared with the Hero 642 canal preparation system following the sequence: 25/12, 30/06, 35/02, and 40/02, 1 mm from the apex. The specimens were then divided into four groups of seven teeth. During biomechanical preparation the teeth were irrigated with 2 ml of distilled water between files. Each group of specimens (n=7) received a final irrigation with 100 ml of the following irrigants that were activated with ultrasound for 3 minutes: Group 1- distilled water; Group 2- 0.2% chlorhexidine digluconate (CHX); Group 3- 2.5% sodium hypochlorite (NaOCl); and Group 4-the filtrate obtained after combining 0.2% CHX and 2.5% NaOCl. The apical portions of the root canals from each group were then submitted to histological processing and analyzed using optical microscopy. RESULTS: Results showed statistical differences between the groups (p<0.01). Groups 1 and 2 (distilled water and 0.2% CHX respectively) were statistically similar in terms of a greater amount of debris, whereas 2.5% NaOCl and the filtrate were more efficient in removal of debris. CONCLUSION: There is no additional benefit in terms of debris removal from root canal walls by irrigating with the filtrate obtained from the combination of NaOCl and CHX when compared to using NaOCl alone. CLINICAL SIGNIFICANCE: The findings of this study suggest the time and expense of preparing and using a combination of NaOCl and CHX is not warranted compared to using NaOCl alone for root canal irrigation.

Effect of 980-nanometer diode laser on root canal permeability after dentin treatment with different chemical solutions.

This study evaluated the effect of 980-nm diode laser at different parameters on root canal dentin permeability associated with different irrigants. Seventy-five canines were sectioned at 15 mm from the apex, prepared mechanically up to #40 .02 instrument, and irrigated with 2 mL distilled water. Final irrigation (10 mL) was used as follows: (1) distilled water; (2) 1% NaOCl; (3) 17% ethylenediaminetetraacetic acid + a cationic surfactant cetyltrimethylammonium bromide (EDTAC). Laser was applied at 1.5 or 3.0 W as either continuous wave or pulsed wave (100 Hz). The teeth were then processed histochemically, the percentage of copper ion penetration into the dentin of the canal walls was counted, and the data were analyzed statistically with the Tukey-Kramer test (alpha < .01). When laser was associated with water, an increase in permeability was found, whereas permeability decreased when associated with EDTAC. Dentin permeability after laser irradiation was directly dependent on the solution used for final irrigation.

Tratamento de dentes traumatizados com rizogênese incompleta: apicificação / Treatment of traumatized teeth with incomplete apex: apexification

Introdução e objetivo: Buscou-se apresentar dois casos clínicos de dentes traumatizados cujos ápices se apresentavam radiograficamente abertos e cujos elementos dentais estavam sem fratura. Relato de caso: Nesses casos, a instrumentação deve ser realizada com leve pressão do instrumento contra as paredes, em virtude da pequena espessura delas. Sendo assim, a escolha da solução irrigante torna-se fundamental, uma vez que suas propriedades químicas específicas suprirão a deficiência do preparo mecânico. Curativos à base de hidróxido de cálcio e propilenoglicol foram feitos e trocados em períodos de 7 dias, 15 dias, 3 trocas a cada 30 dias e uma troca após 3 meses, até a formação de barreira apical calcificada, período no qual se obturou o canal com a técnica de cone único e cimento Grossman. Conclusão: A conduta clínica utilizada proporcionou a formação de barreira apical calcificada, restituindo o equilíbrio biológico e funcional da estrutura dental e garantindo o sucesso do tratamento.

Introduction and objective: Two cases reports of traumatized teethwith incomplete apexes and no tooth fracture. Case report: In these cases, instrumentation should be performed with no pressure to the walls due to the decreased thickness, therefore, the irrigating solution is fundamental to achieve ideal biomechanical preparation. Calcium hydroxide intracanal dressings between sessions were applied at 7 days,15 days, 3 changes every 30 days and a change after 3 months, until apical barrier formation, and sealing of the root canal with the single gutta-percha point technique with Grossman´s cement. Conclusion: The used clinical protocol efficiently formed the calcified root barrier and biological and functional equilibrium was achieved guaranteeing the treatment success.

Oral undifferentiated high-grade pleomorphic sarcoma: report of a case.

The current World Health Organization classification considers the existence of an undifferentiated unclassifiable category of pleomorphic sarcomas, defined as a group of pleomorphic high-grade sarcomas. Undifferentiated high-grade pleomorphic sarcoma represents about 5% of all soft tissue sarcomas in adults and occurs more commonly in the extremities. In the oral cavity, undifferentiated pleomorphic sarcoma is extremely rare. We report a case of undifferentiated high-grade pleomorphic sarcoma located in the floor of the mouth in a man 56 years old. Microscopically, spindle-shaped cells with accented pleomorphism arranged in a storiform pattern, several bizarre giant cells, and frequent atypical mitoses were observed. The tumor cells were positive only for vimentin, with focal positivity for CD68. The patient was treated by surgery and postoperative radiation therapy, and after 25 months, no recurrence was observed.

Ocorrência de traumatismo dental e uso do protetor bucal em praticantes de pólo aquático / Dental trauma and the use of mouthguards by water polo players

O presente estudo verificou a ocorrência do traumatismo dental e o uso de protetores bucais de jogadores de pólo aquático. Cinqüenta e dois atletas responderam a questionário auto-aplicável. A análise dos resultados mostrou que 57,8% dos cirurgiões-dentistas dos atletas sabiam da prática do esporte, mas apenas 26,3% destes indicaram seu uso, apesar de 50% já terem sofrido traumatismo dental durante o esporte. O teste de Dunn demonstrou que com o aumento do tempo da prática do esporte aumentava a prevalência de traumas dentais e de estruturas de suporte (p<0,001); 96,6% dos atletas conhecem o protetor bucal e sabem de sua importância, porém nenhum faz uso do dispositivo (p<0,001). Conclui-se que o uso do protetor bucal não é disseminado entre estes atletas e que a orientação do cirurgião-dentista é essencial para mostrar que o dispositivo protege e dá segurança.

The present study verifyed the prevalence of dental trauma, and use of mouthguards in water polo players. Fifty-two athletes answered an auto-applicable survey. Results showed: 57.8% of the athletes dentist knew that they practiced the sport but only 26.3% indicated the use of mouthguards, although 50% had already suffered dental trauma during practice. Statistical analysis with the Dunn test showed that an increase in years of practice increased the prevalence of dental and surrounding structure trauma (p<0,001); 96.6% of the athletes knew of the existence of mouth guards and their importance, however, no one used them (p<0,001). We can conclude that mouthguards are not used among water polo players, and the dentists' orientation is essential to stimulate use and show that they protect during the practice of sport.

Chemical analysis of the flocculate formed by the association of sodium hypochlorite and chlorhexidine.

OBJECTIVE: The association of chlorhexidine (CHX) and sodium hypochlorite (NaOCl) to enhance their chemical properties during root canal biomechanical preparation can lead to a brown flocculate being formed. Therefore, this study evaluated the metals present in their association by atomic absorption spectrophotometry, and evaluated a possible reagent that could dissolve the flocculate, allowing its clinical use. STUDY DESIGN: Five concentrations of CHX and NaOCl were mixed (2.5% NaOCl + 0.2% CHX, 2% CHX + 0.5% NaOCl, 2% CHX + 5% NaOCl, 0.2% CHX + 0.5% NaOCl, and 0.2% CHX + 5% NaOCl). Methanol and hexane, acetic acid, and vinegar were evaluated to dissolve the flocculate. RESULTS: A flocculate was formed with all proportions and concentrations. Spectrophotometry analysis showed the presence of Ca, Fe, and Mg. CONCLUSION: It can be concluded that the association proposed led to the formation of brown flocculate regardless of concentration and proportion.

Effect of eugenol-based endodontic cement on the adhesion of intraradicular posts.

The present study evaluated, in vitro, the influence of an eugenol-based endodontic sealer (EndoFill) on the adhesion of intra-radicular posts cemented with a resin-based cement (Enforce) ou a zinc phosphate cement. Twenty-four single-rooted maxillary canines were divided into 2 groups (n=12) and obturated with either gutta-percha points plus EndoFill or gutta-percha points alone (no cement). In each group, half of intracanal posts (n=6) were cemented with Enforce resin-based cement and half with zinc phosphate cement. Specimens were submitted to pull-out test in an Instron machine and tensile force was applied at a crosshead speed of 0.5 mm/min until post dislodgement. The maximum forces required for post removal was recorded (N) and means were submitted to statistical analysis by Kruskal-Wallis test (p<0.01). Posts cemented with zinc phosphate cement were significantly more retentive (353.4 N) than those cemented with Enforce (134.9 N) (p<0.01). Regarding the influence of the eugenol-based cement (EndoFill) on post retention, there was statistically significant difference (p<0.01) only between the groups cemented with Enforce, i.e., in the canals filled with EndoFill + guta-percha there was lower bond strength than in the canals filled with gutta-percha points alone (101.5 and 168.2 N, respectively). In conclusion, the zinc-phosphate-based cement showed greater post retention than the resin-based cement. The findings of this study suggest that the eugenol-containing sealer interfered with the adhesive properties of the resin-based cement.