Effect of different obturation techniques on sealer penetration into dentinal tubules after final irrigation with XP-Endo finisher file

The first objective of this research was to evaluate the effectiveness of XP-Endo Finisher on dentinal tubule penetration of irrigation solution using confocal laser scanning microscopy. The main purpose of this research was to compare the effect of cold lateral condensation, continuous wave obturation and core-carrier based techniques on sealer penetration. Sixty mandibular premolars were prepared and allocated into two experimental groups (n=30) as the final irrigation technique and obturation technique experiment. In the final irrigation technique experiment, final irrigation was performed with XP-Endo Finisher, passive ultrasonic irrigation (PUI) and conventional needle irrigation (CNI) (n=10). The roots in the obturation technique experiment were also assigned into 3 groups and obturated with cold lateral condensation, continuous-wave obturation and core-carrier techniques (n=10). The most effective activation method, which emerged as a result of the first part of this study, was used as the final irrigation method in the obturation technique experiment. Then, all roots were sectioned in 1-mm-thick slices at 3mm from the apex for scanning. In terms of depth and percentage of material penetration, CNI exhibited significantly the lowest values and no significant difference was found between others. Also, there was no significant difference among obturation methods. In conclusion, XP-Endo Finisher and PUI are more effective than CNI on irrigant penetration. Sealer penetration into dentinal tubules is independent of obturation techniques.

El objetivo principal de esta investigación fue evaluar la eficacia de XP- Endo Finisher en la penetración de la solución de irrigación en los túbulos dentinarios mediante microscopía de láser confocal. Se prepararon sesenta premolares mandibulares y se distribuyeron en dos grupos experimentales (n=30) según el tipo de método de evaluación utilizado. En el experimento de la técnica de irrigación final, la irrigación final se realizó con XP-Endo Finisher, irrigación ultrasónica pasiva (PUI) e irrigación con aguja convencional (CNI) (n=10). Las raíces en el experimento de la técnica de obturación también se asignaron en 3 grupos y se obturaron con técnicas de condensación lateral fría, obturación de onda continua y portador de núcleo (n=10). El método de activación más eficaz, que surgió como resultado de la primera parte de este estudio, se utilizó como método de irrigación final en el experimento de la técnica de obturación. Luego, todas las raíces se seccionaron en muestras de 1mm de espesor. En términos de profundidad y porcentaje de penetración del material, CNI exhibió significativamente los valores más bajos y no se encontraron diferencias significativas entre los demás. Además, no hubo diferencias significativas entre los métodos de obturación. En conclusión, XP-Endo Finisher y PUI son más efectivos que CNI en la penetración del irrigante. La penetración del sellador en los túbulos dentinarios es independiente de las técnicas de obturación.

Evaluation of the dentinal tubule penetration of an endodontic bioceramic sealer after three final irrigation protocols

Introduction: This study aimed to evaluate the dentinal tubule penetration of an endodontic bioceramic sealer, Sealer Plus BC, after three final irrigation protocols. Methods: Thirty distobuccal roots of maxillary molars were selected. Root canal preparation was performed up to an #40.06 instrument (X1 Blue) under 2.5% sodium hypochlorite irrigation. Specimens were randomly divided into three groups (n=10), according to the final irrigation protocol: G-NaOCl (2.5% sodium hypochlorite + PUI), G-SS (0.9% saline solution + PUI) and G-H20 (Deionized water + PUI). After final irrigation protocols, all specimens were irrigated with phosphate buffer solution. Root canal obturation was performed using the single cone technique and Sealer Plus BC, stained with a specific fluorophore. Specimens were transversely sectioned and each root third was evaluated in a confocal scanning laser microscopy. Images obtained were analyzed for sealer penetration in the dentinal tubules. Results: Dentinal tubule penetration of Sealer Plus BC was not observed in any root third, regardless of the final irrigation protocol investigated. Conclusions: Sealer Plus BC dentinal tubule penetration was not observed after none of the protocols tested. Dentinal tubule penetrability of Sealer Plus BC may be related to other factors rather than the final irrigation protocol.

Capacidad de Penetración y Difusión de la Medicación, Intraconducto en Túbulos Dentinales, Conductos Laterales e Istmos. Una Revisión Sistemática

RESUMEN: El objetivo de la terapia endodóntica consiste en tratar o prevenir la periodontitis apical. La efectiva eliminación o disminución de microbiota es esencial para la reparación periapical. Debido a esto, se utiliza el empleo de medicamentos intraconductos para tratar químicamente el sistema de conductos radiculares, y cobra relevancia la capacidad de penetración y difusión de dicho medicamento para entrar en contacto directo con los microorganismos que penetren dentro de los túbulos dentinales, conductos laterales e itsmos. Se realizó una revisión de la literatura en bases de datos electrónicas con los buscadores "Pubmed, Scielo y Google Académico", utilizando palabras clave para identificar la literatura publicada relevante en inglés. El análisis y los criterios de elegibilidad se documentaron de acuerdo con los elementos de informe para revisiones sistemáticas y meta-análisis (Preferred Reporting Items for Systematic Reviews and Meta-Analysis, PRISMA). No se impusieron restricciones sobre la fecha de publicación. Se recogieron datos sobre capacidad de difusión de medicación intraconductos en túbulos dentinales, conductos laterales e itsmos radiculares y se sometieron a análisis descriptivo de datos. La búsqueda bibliográfica en bases de datos electrónicas según los criterios de inclusión arrojó 45 títulos y resúmenes. Entre ellos, 7 artículos fueron seleccionados. Se determinó un rango de penetración del medicamento muy variable, entre 27,7 - 2350 μm y rango de difusión de 200-500 μm. Hay pocos estudios publicados que reporten la capacidad de penetración y difusión de la medicación intraconductos. El vehículo empleado y diámetro de las partículas en la preparación del medicamento y la eliminación de la capa de desecho aumentaría la capacidad de penetración/difusión del medicamento intraconductos dentro del túbulo dentinal, conductos laterales e itsmo.

ABSTRACT: The objective of endodontic therapy is to treat or prevent apical periodontitis. The effective elimination or reduction of the microbiota is essential for periapical repair. Due to this, the use of intracanal drugs is used to chemically treat the root canal system, and the penetration and diffusion capacity of said drug becomes relevant to come into direct contact with the microorganisms that penetrate inside the dentinal tubules, lateral canals and isthmus. A literature review was carried out in electronic databases with the search engines "Pubmed, Scielo and Google Academic", using keywords to identify the relevant published literature in English. The analysis and eligibility criteria were documented according to the reporting items for systematic reviews and meta-analyzes (Preferred Reporting Items for Systematic Reviews and Meta-Analysis, PRISMA). No restrictions were placed on the date of publication. Data on intracanal drug diffusion capacity in dentinal tubules, lateral canals and root isthmus were collected and subjected to descriptive data analysis. The bibliographic search in electronic databases according to the inclusion criteria yielded 45 titles and abstracts. Among them, 7 articles were selected. A highly variable drug penetration range was determined, between 27.7 - 2350 μm and a diffusion range of 200-500 μm. There are few published studies that report the penetration and diffusion capacity of intracanal medication. The vehicle used and the diameter of the particles in the preparation of the drug and the elimination of the waste layer would increase the penetration / diffusion capacity of the drug within the dentinal tubule, lateral canals and isthmus.

Influence of root canal filling techniques on sealer penetration and gutta percha/sealer ratio: a confocal laser scanning microscopy analysis / Influência das técnicas de obturação do canal radicular na penetração do cimento e na relação guta-percha / cimento: uma análise por microscopia de varredura confocal a laser

Objective: The influence of four root canal filling techniques on the penetration of an endodontic sealer into dentinal tubules and the gutta percha/ sealer ratio (GP/SR) in root canals was evaluated using confocal laser scanning microscopy (CLSM). Material and Methods: Roots of the maxillary central incisors (n=40) were prepared with ProTaper Universal files up to file F5 and assigned to five groups: continuous wave condensation, lateral condensation, single cone, Thermafill®, and negative control group. After root canal filling with gutta-percha and AH26, along with the addition of 0.01% fluorescein, the roots were cut into 2-mm slices. Using CLSM, the specimens were transversely sectioned at 3, 6, and 10 mm from the apex. Results: Sealer penetration was deeper and more frequent at 10 mm than at the 6mm and 3mm for all obturation technique. Penetration was not significantly affected by obturation techniques except single master cone tecnique. Single cone technique demonstrated the lowest sealer penetration at all levels. However, sealer thickness was strongly dependent on obturation technique. Termafill® demostrated superior GP ratio followed by continuous wave condensation, lateral condensation and single cone. Conclusion: In conclusion, the single cone technique resulted in lower sealer penetration than the other techniques, which did not differ significantly from each other. However, sealer thickness was strongly dependent on obturation technique. Termafill® demostrated superior GP ratio followed by continuous wave condensation, lateral condensation and single cone. (AU)

Objetivo: A influência de quatro técnicas de obturação do canal radicular na penetração de um cimento endodôntico nos túbulos dentinários e a relação gutapercha / cimento (GP / CIM) em canais radiculares foram avaliadas por microscopia de varredura confocal a laser (MVCL). Material e Métodos: As raízes de incisivos centrais superiores (n = 40) foram preparadas com limas ProTaper Universal até a lima F5 e distribuídas em cinco grupos: condensação de onda contínua, condensação lateral, cone único, Thermafill® e grupo de controle negativo. Após o preenchimento do canal radicular com guta-percha e AH26, juntamente com a adição de 0,01% de fluoresceína, as raízes foram cortadas em fatias de 2 mm. Usando MVCL, as amostras foram seccionadas transversalmente a 3, 6 e 10 mm do ápice. Resultados: A penetração do cimento foi mais profunda e mais frequente em 10 mm do que nos 6 mm e 3 mm para todas as técnicas de obturação. A penetração não foi significativamente afetada pelas técnicas de obturação, exceto pela técnica de cone mestre único. A técnica de cone único demonstrou a menor penetração do cimento em todos os níveis. No entanto, a espessura do cimento foi fortemente dependente da técnica de obturação. O Termafill® demonstrou uma relação superior de GP, seguida por condensação de onda contínua, condensação lateral e cone único. Conclusão: Em conclusão, a técnica de cone único resultou em menor penetração do cimento do que as outras técnicas, que não diferiram significativamente uma da outra. No entanto, a espessura do cimento foi fortemente dependente da técnica de obturação. O Termafill® demonstrou uma relação superior de GP, seguida por condensação contínua das ondas, condensação lateral e cone único. (AU)

Effect of laser treatment of dentin hypersensitivity on pulp chamber temperature / 国际生物医学工程杂志

Objective To compare the pulp chamber temperature changes of Nd:YAP laser, Nd:YAG laser and semiconductor laser with the same power during dentin hypersensitivity treatment, and to evaluate the safety of these three laser treatments for dentin hypersensitivity. Methods 50 intact third molars were collected to prepare the dentin hypersensitivity model. The samples were randomly divided into Nd:YAP laser group (n=15), Nd:YAG laser group (n=15), semiconductor laser group (n=15), and blank control group (n=5). Each experimental group was divided into three subgroups (n=5) of 0.9 W, 1.4 W, and 1.8 W according to the laser power. The experiments were conducted with the corresponding laser parameters and thermocouple thermometer was used to record the temperature changes in the pulp chamber. The control group does not do any processing. After laser irradiation, one sample was randomly taken from each group and the morphology of dentin tubules was observed by scanning electron microscopy. Results When different power lasers were used to irradiate the samples, the temperatures of the pulp chamber in each group were increased. Among them, the temperature rise of the pulp chamber was smallest in the Nd:YAP laser group, followed by the semiconductor laser group, and the temperature rise was highest in the Nd:YAG laser group, but it was still lower than 5.5 ° C that could cause pulp necrosis. Scanning electron microscopy results showed that after irradiation with different power lasers, the diameters of most dentinal tubules in the Nd:YAG laser group and the semiconductor laser group were narrowed or even melted, and the effect was better than that of the Nd:YAP laser group. Conclusion The treatment using Nd:YAP laser, Nd:YAG laser and semiconductor laser for dentin hypersensitivity will increase the temperature of the pulp chamber. However, the temperature rise is less than 5.5℃and that will not cause irreversible damage to the pulp tissue. Nd:YAG laser and semiconductor laser have better dentinal tubule blocking effect, which is more suitable for laser dentin desensitization treatment than Nd:YAP laser.

The effects of different Er: YAG laser parameters combined with dole fluorine on dentinal tubules / 口腔疾病防治

Objective@# To explore the effects of Er: YAG lasers with different pulse energies and of Er: YAG lasers combined with Duraphat on dentine surface morphology and the dentinal tubule exposure rate, thereby providing a theoretical basis and parameters for clinically treating dentine hypersensitivity with Er: YAG lasers.@*Methods @# Dentinal tubule exposure models were divided into five groups, namely, group A (single Er: YAG laser exposure), group B (Duraphat+ Er: YAG laser), and group C (Er: YAG laser+Duraphat), which were exposed to 6 levels of pulse energy (80 mJ/P- 250 mJ/P), and experimental control group D (Duraphat group) and blank control group E. Scanning electron microscopy was used to observe dentine surface morphology and dentinal tubule closure in these groups, and Image-Pro Plus 6.0 software was used for image analysis to measure the exposure rates of the five groups of dentinal tubules.@*Results@#The dentinal tubule exposure rates for the A-D groups were significantly lower than that of the E group (P < 0.001); when the Er: YAG laser pulse energy was less than 250 mJ/P, the dentinal tubule exposure rates for the A-C groups were all lower than that of the D group, but when the pulse energy was higher than 250 mJ/P, the dentinal tubule exposure rates for the A-C groups were higher than that of the D group, showing significant differences (P < 0.001); under the same handling method, when the pulse energy was 80~200 mJ/P, the dentinal tubule exposure rate decreased as the pulse energy increased. If the pulse energy reached 250 mJ/P, the exposure rate of the dentinal tubules increased instead. There were apparently no significant differences between 80 mJ/P, 100 mJ/P, 160 mJ/P and 200 mJ/P in the A and C groups or between 80 mJ/P and 100 mJ/P in the B group (P > 0.05), while significant differences existed among the other groups (P< 0.05). Under the same pulse energy, the dentinal tubule exposure rates were A group > C group >B group; under different pulse energies, there existed significant differences between the A and B groups (P < 0.05); when the pulse energy was 120~250 mJ/P, there were significant differences between the B and C groups (P < 0.05), while there were no significant differences among other groups (P＜0.05).@*Conclusion@#Er: YAG lasers can close the dentinal tubules and play a cooperative role if combined with Duraphat; the effects of laser exposure are better if fluorine is applied beforehand; and dentinal tubule closure is positively correlated with the pulse energy of Er: YAG lasers within a certain energy scope, but when the pulse energy reaches 200 mJ/P, the dentine surface is excessively fused and injured.

Impact of Dentinal Tubule Orientation on Dentin Bond Strength / 华中科技大学学报（医学）（英德文版）

This study aimed to determine the impact of dentinal tubule orientation on dentin bond strength to provide a reference for clinical cavity preparation in resin-bonded restoration.Patients aged 13-16 years were selected,including 18 males and 21 females.Forty-eight human maxillary first premolars from orthodontic extractions were chosen to prepare the test models with the dentinal tubule orientations perpendicular and parallel to the bonding substrate.The test models in the vertical and parallel groups were divided into three groups:total-etching with 20％ phosphoric acid,total-etching with 35％ phosphoric acid and self-etching,with the dentinal tubule surfaces bonded with composite resin blocks in each group.After the standard test models of dentinal tubule-composite resin blocks were placed in distilled water and stored at 37℃ for 24 h,shearing tests were performed using a universal material testing machine at a crosshead speed of 0.5 mm/min.The bond strength values in the vertical group were 19.33±1.59 MPa for the 20％ phosphoric acid group,21.39±2.34 MPa for the 35％ phosphoric acid group,and 16.88±1.54 MPa for the self-etching group.The bond strength values in the parallel group were 24.53±1.99MPa for the 20％ phosphoric acid group,25.16±2.88 MPa for the 35％ phosphoric acid group,and 20.83±1.99 for the self-etching group.After using same total-etching adhesive,the shear bond strength of the parallel group was higher than that of the vertical group,and the difference was statistically significant (P＜0.05).Regardless of vertical group or parallel group,the difference in the bond strength value between the total-etching groups and the self-etching group was statistically significant (P＜0.05).It was concluded that the dentin bonding substrate which was parallel to the direction of the dentin tubule achieved an improved bond strength;the total-etching adhesives achieved higher bond strengths in dentin bond than the self-etching adhesives.

Impact of Dentinal Tubule Orientation on Dentin Bond Strength / 华中科技大学学报（医学）（英德文版）

This study aimed to determine the impact of dentinal tubule orientation on dentin bond strength to provide a reference for clinical cavity preparation in resin-bonded restoration.Patients aged 13-16 years were selected,including 18 males and 21 females.Forty-eight human maxillary first premolars from orthodontic extractions were chosen to prepare the test models with the dentinal tubule orientations perpendicular and parallel to the bonding substrate.The test models in the vertical and parallel groups were divided into three groups:total-etching with 20％ phosphoric acid,total-etching with 35％ phosphoric acid and self-etching,with the dentinal tubule surfaces bonded with composite resin blocks in each group.After the standard test models of dentinal tubule-composite resin blocks were placed in distilled water and stored at 37℃ for 24 h,shearing tests were performed using a universal material testing machine at a crosshead speed of 0.5 mm/min.The bond strength values in the vertical group were 19.33±1.59 MPa for the 20％ phosphoric acid group,21.39±2.34 MPa for the 35％ phosphoric acid group,and 16.88±1.54 MPa for the self-etching group.The bond strength values in the parallel group were 24.53±1.99MPa for the 20％ phosphoric acid group,25.16±2.88 MPa for the 35％ phosphoric acid group,and 20.83±1.99 for the self-etching group.After using same total-etching adhesive,the shear bond strength of the parallel group was higher than that of the vertical group,and the difference was statistically significant (P＜0.05).Regardless of vertical group or parallel group,the difference in the bond strength value between the total-etching groups and the self-etching group was statistically significant (P＜0.05).It was concluded that the dentin bonding substrate which was parallel to the direction of the dentin tubule achieved an improved bond strength;the total-etching adhesives achieved higher bond strengths in dentin bond than the self-etching adhesives.

Clinical assessment on application of Er:Cr:YSGG laser in dentinal hypersensitivity reduction / 대한구강보건학회지

OBJECTIVES: We aimed to evaluate the effectiveness of Er:Cr:YSGG laser therapy on the reduction of dentinal hypersensitivity while taking into account the length and depth of the cervical abrasion. METHODS: We included adults (age, 20-60 years) with at least 2 hypersensitive teeth. The hypersensitive teeth were stimulated with a pressure-indicating probe and an air syringe. The response of the subjects to this stimulation was quantified using a visual analog scale (VAS) and Schiff air sensitivity score. The patients were treated at baseline, immediately after laser treatment, and at 1, 2, and 4 weeks after the Er:Cr:YSGG laser therapy. The results were analyzed by repeated measure analysis of variance (ANOVA) and Bonferroni's post hoc test. RESULTS: The values of tactile test and air blast test showed statistically significant differences between the following time points: baseline and immediately after laser treatment, baseline and first week after treatment, and immediately after laser treatment and first week after treatment (P0.05). The depth and width of the cervical abrasion was not statistically significant in dentinal hypersensitivity reduction (P>0.05). CONCLUSIONS: The use of Er:Cr:YSGG laser therapy reduced dentinal hypersensitivity, especially immediately after laser treatment. The depth and width of the cervical abrasion is not statistically significant in dentinal hypersensitivity reduction.

Calclum Sodium Phosphosilicate : A Promising Desensitizing Agent.

Dentinal hypersensitivity is a common and chronic condition affecting the teeth in a stable percentage of population. Success with treatment of this condition has been limited at best. A new dentifrice containing Calcium Sodium Phosphosilicate material has been developed that results in a significant amount of tubule occlusion reducing tooth hypersensitivity. In this article, Calcium Sodium Phosphosilicate containing dentifrice, which is showing promise is analyzed, based on evidences.

Development of nano-fluid movement measuring device and its application to hydrodynamic analysis of dentinal fluid / 대한치과보존학회지

This study was aimed to develop an instrument for real-time measurement of fluid conductance and to investigate the hydrodynamics of dentinal fluid. The instrument consisted of three parts; (1) a glass capillary and a photo sensor for detection of fluid movement, (2) a servo-motor, a lead screw and a ball nut for tracking of fluid movement, (3) a rotary encoder and software for data processing. To observe the blocking effect of dentinal fluid movement, oxalate gel and self-etch adhesive agent were used. BisBlock (Bisco) and Clearfil SE Bond (Kuraray) were applied to the occlusal dentin surface of extracted human teeth. Using this new device, the fluid movement was measured and compared between before and after each agent was applied. The instrument was able to measure dentinal fluid movement with a high resolution (0.196 nL) and the flow occurred with a rate of 0.84 to 15.2 nL/s before treatment. After BisBlock or Clearfil SE Bond was used, the fluid movement was decreased by 39.8 to 89.6%.

The effect of smear layer treatment on the microleakage / 대한치과보존학회지

The purpose of this study was to compare the sealing ability of root canal obturation with or without the treatment of smear layer. Eighty extracted human teeth with one canal were selected. Instrumentation was performed with crown-down technique. After instrumentation, root canals of the NaOCl group and NaOCl-6 group were irrigated with 3% NaOCl. EDTA group and EDTA-6 group were irrigated with 17% EDTA. Then all teeth were obturated using continuous wave obturation technique. NaOCl group and EDTA group were immersed in methylene blue solution for 84hours. NaOCl-6 group and EDTA-6 group were immersed in methylene blue solution for 6months. The teeth were sectioned at 1.5 mm (Level 1), 3.0 mm (Level 2) and 4.5 mm (Level 3) from the root apex. The length of dye-penetrated interface and the circumferential length of canal at each level were measured using Sigma-Scan Pro 5.0. 1. The mean leakage ratio was decreased cervically. 2. NaOCl group showed higher mean leakage ratio than EDTA group at each level. But there was significant difference at level 1 only (p < 0.05). 3. NaOCl-6 group showed higher mean leakage ratio than EDTA-6 group at each level. But there was significant difference at level 1 only (p < 0.05). 4. NaOCl-6 group showed higher mean leakage ratio than NaOCl group at each level. But there was significant difference at level 1 only (p < 0.05). 5. EDTA-6 group showed higher mean leakage ratio than EDTA group at each level. But there was no significant difference. 6. In NaOCl group and NaOCl-6 group, scanning electron micrographs of tooth sections generally covered with smear layer. In EDTA group and EDTA-6 group, tooth sections showing the penetration of sealers to opened dentinal tubules. The results suggest that removal of smear layer was effective to reduce the apical microleakage of the root canal.

A SEM study of dentinal tubule sealing effect of desensitizing agent applicated after root planning / 대한치주과학회지

The purpose of this study was to observe the degree of surface obliteration of dentinal tubule using Gluma(R) desensitizer and MS coat(R) with 15 specimens made out of 15 extracted lower incisors. They were divided into Root planning group(control), Gluma(R) desensitizer group(testI) and MS coat(R) group(testII). Degree of obliteration was examined under the scanning electron microscope(x2000). The following results were obtained : 1. In the root planning group(control), the complete open of dentinal tubule surface was accounted for 73.8%, the partial obliteration for 17.2% and the complete obliteration for 9.0%. 2. In the Gluma(R) desensitizer group (test I), the complete open of dentinal tubule surface was accounted for 23.6%, the partial obliteration for 42.8% and the complete obliteration for 33.6%. 3. In the MS coat(R) group (test II), the complete open of dentinal tubule surface was accounted for 19.2%, the partial obliteration for 45.6% and the complete obliteration for 35.2%. 4. The average number of open dentinal tubules in the control was significantly higher than in the testI and II(P<0.05), but there were no statistically significant differences between the test I and II. 5. The average number of the partially obliterated and the completely blocked dentinal tubules in the control was significantly lower than the testI and II(P<0.05), but there were no statistically significant differences between the test I and II. The results of this study suggest that Gluma(R) desensitizer and MS coat(R) is significantly effective on dentinal tubule obliteration, therefore they were effective on hypersensitivity caused by periodontal treatment

The Effect of EDTA, Tetracycline-HCl, and Citric Acid on Diseased Root Surfaces: The SEM Study / 대한치주과학회지

The goal of periodontal therapy is the periodontal regeneration by the removal of microorganisms and their toxic products from the periodontally diseased root surface. To achieve periodontal regeneration, root conditioning as an adjunct to root planing has been done. There are low pH etchants such as citric acid, tetracycline-HCl, and EDTA solution which is a neutral chelating agent. The purpose of present study was to examine the effect of root conditioning by citric acid, tetracycline HCl, and EDTA. Total 35 root specimens(6x3x2mm) were prepared from the periodontally diseased teeth, scaled and root planed. The specimens were treated with normal saline for 1 minute, saturated citric acid(pH 1) for 3 minutes, 50mg/ml tetracycline-HCl(pH 2) for 5 minutes, 15% EDTA(pH 7) for 5 minutes using rubbing technique. The specimens were examined under scanning electron microscopy at 1000, and 3000 magnification. On the microphotographs taken at 1000 magnification, the numbers of opened and patent dentinal tubules per unit area(10,640micrometer2) were counted. And the diameters of opened dentinal tubules per unit area(10,640micrometer2) were measured. The differences of number and diameter among all groups were statistically analyzed by Kruskal Wallis Test. The results were as follows; 1. In the specimens applied with normal saline(control group), the root surface was finely cracked, and was covered by irregular smear layer. Neither exposed dentinal tubules nor any patent dentinal tubules could be seen. 2. In the specimens applied with saturated citric acid(experimental 1 group), the globular collagen fibers were exposed around the peritubular space, and many dentinal tubules were revealed. 3. In the specimens applied with tetracycline-HCl(experimental 2 group), the process-like collagen fibers were exposed around the peritubular space, and some dentinal tubules were revealed. 4. In the specimens applied with 15% EDTA(experimental 3 group), the root surface was covered by the collagenous fibrillar network, and many dentinal tubules were revealed. 5. The numbers of opened and patent dentinal tubules were significantly more in exp. 1 group and exp. 3 group than in exp. 2 group(P<0.05). But there was no significant difference between exp. 1 group and exp. 3 group. In control group, the number of opened and patent dentinal tubules could not be counted because any dentinal tubules couldn't be seen. 6. The diameter of opened dentinal tubules was significantly smaller in exp. 1 group and exp. 3 group than in exp. 2 group(P<0.05). But there was no significant difference between exp. 1 group and exp. 3group. In control group, the diameter of opened dentinal tubules could not be measured because any dentinal tubules couldn't be seen. The results demonstrate that root conditioning with citric acid, tetracycline- HCl, and EDTA is more effective in periodontal healing than only root planing, and 15% EDTA solution can replace low pH etching agents such as citric acid, tetracycline-HCl for root conditioning.

Study on the Changes of Dentinal Hypersensitivity and Surface Characteristics Following the Various Root Treatment / 대한치주과학회지

Exposure of the root surface due t o gingival recession after periodontal surgery, elicit pain response when exposed to mechanical, heat, chemical o r osmotic irritation. Especially patients treated with periodontal surgery, show high frequency. There have been reports that the 1 out of 7 patients complains of dentinal hypersensitivity. There have been many studies on the clinical effects of various materials on the treatment of dentinal hypersensitivity. The purposes of this study were to evaluate die effect of sodium chloride and potassium oxalate and to observe the relationship between the dentinal hypersensitivity and surface characteristics such as dentinal tubule size and number. This study included 20 teeth which were scheduled for extraction and had no pulpal disease. These teeth were divided into Root planing group, EDTA group, NaCl group and Oxalate group. Dentinal hypersensitivity is measured by tactile, pressured air and cold water using NRS (Numerical Rating Scales). Teeth were extracted under local anesthesia and each specimen was sectioned to a size about 3 X 5 mm and was examined under the scanning electron microscope (X2,000) The results were as follows, 1. The EDTA group exhibited significantly increased dentinal hypersensitivity comparing with the other groups. 2. The NaCl and Oxalate groups showed significantly reduced dentinal hypersensitivity comparing with the EDTA group. 3. As a method for dentinal hypersensitivity measurement, it was presumed that tactile sensitivity test was not sensitive method but air blast test and cold water test were adequate method. 4. In a SEM study, the root planing group exhibited amorphous smear layer and showed no dentinal tubule orifice, but the EDTA group showed the large number of dentinal tubules. On the other hand, the NaCl and Oxalate groups did not show exposed dentinal tubules. The NaCl group showed more rough root surface than the EDTA group, anti the Oxalate group showed many participates to be presumed as calcium oxalate particle. As the results from this study, root planing couldn't expose the dentinal tubule and NaCl and potassium oxalate occluded exposed dentinal tubule effectively. Dentinal hypersensitivity has close relationship with the exposure of dentinal tubules, especially with it's size and number.