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Results for “Tooth Apex”

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At least 595 records · Page 33Linked to original sources

PubMed1998

Evaluation of the apical seal of root canal fillings with different methods.

The purpose of the study was to compare dye penetration methods conducted passively, under negative pressure, or under high pressure conditions. Ninety human maxillary incisors were instrumented and obturated with either the lateral condensation or single cone technique. India ink was used as a dye for passive and negative pressure (60 Torr) penetration methods. For dye penetration under high pressure conditions (200 MPa), a colored epoxy resin was used. Apical leakage was linearly measured evaluating both the root surface that showed the highest degree of penetration and all four surfaces of each root. The results revealed no significant difference between passive and negative pressure penetration methods. The amount of apical leakage obtained using dye penetration under high pressure conditions was significantly lower. Lateral condensation and single cone techniques yielded similar sealing abilities. It is concluded that there is no need to use negative pressure for evaluating the sealing ability of root canal fillings in vitro.

Carbon↗

PubMed1998

Ultrasonic root-end preparation: influence of cutting angle on the apical seal.

Apical resection is fundamental in obtaining a correct apical seal. The purpose of this study was to evaluate how the apical root resection angle and the cavity made by ultrasonic retrotips may influence the apical seal. A total of 48 extracted teeth were endodontically treated and sealed by guttapercha vertical compaction: 24 were resected with a 45 degrees angle and 24 with a 90 degrees one. An ultrasound source (P.M. 400 EMS) and a CT5 Scaler were used to make the retrograde cavity that was filled afterwards with EBA-zinc oxide-eugenol alumina-added cement. Apical leakage was determined using fuchsin and assessed after the roots were sectioned longitudinally. Linear dye penetration in dentin and at the interface between dentin and cement was measured with a stereomicroscope (x 12 magnification), and the results were statistically analyzed. Results showed that there was less infiltration both in dentin and in the space between the filling and the dentinal wall in the group with the 90 degrees angle, but this difference was statistically significant (p < 0.0001) only for the dentin. None of the samples showed leakage greater than the depth of the preparation. An apical cavity of 3 mm or more along the vertical axis can produce a safe and effective seal.

Bicuspid↗

PubMed1998

Apical leakage of a new glass ionomer root canal sealer.

A new glass ionomer root canal sealer (Ketac-Endo) has been developed. The purpose of this study was to compare the apical leakage of Ketac-Endo and AH26 using two different filling techniques and a controlled vacuum procedure. Sixty-four extracted human maxillary anterior teeth were instrumented and divided into four groups of 15 roots each. The groups were obturated as follows: group 1, a single cone technique and Ketac-Endo; group 2, a lateral condensation technique and Ketac-Endo; group 3, a single cone technique and AH26; and group 4, a lateral condensation technique and AH26. After storage in 100% humidity at 37 degrees C for 1 wk, the root surfaces were coated with two layers of nail polish and sticky wax. All specimens were immersed in a vacuum flask containing 2% methylene blue dye solution. The air was evacuated with a vacuum pump. The roots were sectioned longitudinally, and the linear extent of dye penetration was measured. Statistical analysis revealed that there were no significant differences between any of the groups.

Bismuth↗

PubMed1998

Apical extrusion of debris using two hand and two rotary instrumentation techniques.

The purpose of this study was to investigate the quantity of apical debris produced in vitro using two hand and two rotary instrumentation techniques. Sixty minimally curved, mature human mandibular premolars with single canals were divided into 4 groups of 15 teeth each and prepared using step-back instrumentation with K-files, balanced force with Flex-R files, Lightspeed nickel-titanium instruments, or .04 taper ProFile Series 29 rotary nickel-titanium files. Debris extruded through the apical foramen during instrumentation was collected on preweighed filters. The mean weight of extruded debris for each group was statistically analyzed using a Kruskal Wallis one-way analysis of variance and a Mann-Whitney U rank sum tested. Although all instrumentation techniques produced apically extruded debris, step-back instrumentation produced significantly more debris than the other methods (p < 0.0001). There was no difference between balanced force hand instrumentation and the two rotary nickel-titanium instrumentation methods (p > 0.05). Hand or engine-driven instrumentation that uses rotation seems to reduce significantly the amount of debris extruded apically when compared with a push-pull (filing) technique. Decreased apical extrusion of debris has strong implications for a decreased incidence of postoperative inflammation and pain.

Bicuspid↗

PubMed1998

Comparison of debris extruded apically in straight canals: conventional filing versus profile .04 Taper series 29.

The purposes of this study were to determine quantitatively the amount of debris and irrigant forced in an apical direction, the frequency of apical plug development, and the time required to prepare canals when a step-back technique using K-files was compared with the .04 Taper system. Sixty-nine extracted teeth with straight canals were divided into four statistically similar groups. Two groups were instrumented either 1 mm short of the apical foramen or to the apical foramen with K-files. The other two groups were instrumented to the same levels using .04 Taper files. The extruded debris and irrigant were collected in preweighed vials. The weight of the debris and volume of irrigant extruded using both techniques were compared and analyzed using paired t test and one-way ANOVA. Tukey's Multiple Comparisons Procedure showed K-files used to the apical foramen extruded significantly more debris than the other three groups (p < 0.01). The .04 Taper files used 1 mm short extruded less debris than the other groups. Significantly more irrigant was extruded when filing was performed to the apical foramen (p < 0.007), regardless of the technique used. More apical plugs were created in teeth filed short of the apical foramen, but the difference between the two preparation techniques was not statistically significant. It took significantly less time to instrument canals with the .04 Taper system than with K-files (p < 0.002).

Analysis of Variance↗

PubMed1998

Immunohistochemical study of apical periodontal cysts.

Periapical lesions, as well as periodontal disease, seems to have cyclic patterns of evolution. Periods of burst may be intercalated with periods of quiescence. Because keratinocyte division must occur during cyst growth, it is presumed that epithelium status could indicate the biological activity of radicular cysts (RCs). Th1 and Th2 are important heterogeneous stages of lymphocyte differentiation. Delayed-type hypersensitivity immune reactions are mediated by Th1 lymphocytes, whereas Th2 populations mediate some types of humoral immune response. Th2 lymphocytes are characterized by high expression of CD30 glycoprotein. Th1 and Th2 lymphocytes have not been evaluated in periapical inflammatory lesions. The purpose of this study was to evaluate CD30+ cells in RCs with atrophic and hyperplastic epithelium. A biotin-streptavidin amplified system was used for identification of CD30 receptor. Results demonstrate increased proportions of Th2 cells in cysts with hyperplastic epithelium. Our results suggest that Th2 cells could be associated with RC growth.

Analysis of Variance↗

PubMed1999

Reaction of dogs' teeth to root canal filling with mineral trioxide aggregate or a glass ionomer sealer.

This study was conducted to observe the reaction of apical tissues of dogs' teeth after root canal filling with gutta-percha and mineral trioxide aggregate (MTA) or a glass ionomer (Ketac-Endo) as a sealer. The root canals were instrumented and filled by the lateral condensation technique with the sealers studied. Animals were killed 6 months later, and the specimens were removed and prepared for histological analysis. Results showed no inflammatory reaction of apical tissue and total closure of the apical foramen of all the teeth sealed with MTA. The teeth sealed with Ketac-Endo showed two cases of partial closure and different degrees of chronic inflammatory reaction. In conclusion, MTA exhibited better biological properties than Ketac-Endo.

Aluminum Compounds↗

PubMed1999

Leakage in roots coronally sealed with different temporary fillings.

This study was aimed at determining the ability of different coronal temporary fillings to prevent corono-apical penetration of bacteria. A total of 103 human teeth, including three controls, were instrumented, obturated with gutta-percha, coronally sealed with either Cavit, Intermediate Restorative Material (IRM), glass-ionomer cement, Cavit/glass-ionomer cement, or IRM/glass-ionomer cement, respectively. Each root was fixed with wax between two chambers: the coronal chamber harboring soy broth with 10(8) colony-forming units of Streptococcus mutans/ml, the apical chamber containing sterile soy broth. The latter was checked daily for turbidity, indicating corono-apical penetration of bacteria. The Cavit group, the IRM group, and the Cavit/glass-ionomer cement group showed significantly more leakage than the glass-ionomer cement group of the IRM/glass-ionomer cement group. If a sample leaked, all except one (IRM/glass-ionomer cement) leaked before day 12. This in vitro study seems to indicate that only glass-ionomer cement and IRM combined with glass-ionomer cement may prevent bacterial penetration to the periapex of root-filled teeth over a 1-month period.

Calcium Sulfate↗

PubMed1999

Comparison of the cleaning efficacy of passive sonic activation and passive ultrasonic activation after hand instrumentation in molar root canals.

The purpose of this study was to compare the cleaning efficacy of passive ultrasonic activation with that of passive sonic activation after hand instrumentation. Sixty curved molar canals were hand-instrumented to size 35 and divided into three groups. Group 1 received no further treatment. Group 2 received 3 min of passive sonic activation. Group 3 received 3 min of passive ultrasonic activation. The roots were split and photomicrographs (x20) were made of the apical 6 mm of canal. A transparent grid was placed over projected images, and the total number of squares covering the apical 6 mm of canal space and the number of squares containing debris were counted. A debris score was calculated for each specimen by dividing the number of squares with debris by the total number of squares. The mean debris scores were 31.6% for hand instrumentation only, 15.1% for the sonic group, and 16.7% for the ultrasonic group. The debris scores for the sonic and ultrasonic activation groups were significantly lower than that for the hand instrumentation only group (p < 0.01); however, there was no significant difference between the sonic and ultrasonic activation groups. Passive sonics after hand instrumentation produces a cleaner canal than hand instrumentation alone and is comparable with that of passive ultrasonics.

Analysis of Variance↗

PubMed1999

In vitro sealing ability of dentin bonding agents and cavity varnish with amalgam as retrofills.

The aim of this study was to test the effect on the seal produced by an amalgam retrofill of two dentin bonding agents (Amalgambond and All-Bond) and a cavity varnish (Copalite). The three materials were tested when placed before the retrofill (group I) and before and after the retrofill (group II). Ninety teeth distributed into three groups were prepared for the retrofilling. Each group was divided into subgroups of I and II. Linear apical leakage was measured by a stereomicroscope after 1 month in dye. All materials permitted dye leakage around the retrofill, regardless of the application type. No statistical difference was found between the Amalgambond subgroups or between the All-Bond subgroups. There was less leakage in varnish group I than group II. Amalgambond group I leaked significantly less than All-Bond group I.

Analysis of Variance↗

PubMed1999

Results of endodontic retreatment: a randomized clinical study comparing surgical and nonsurgical procedures.

Information of "success" rates after surgical or nonsurgical endodontic retreatment is abundant but inconclusive. Reported healing frequencies vary between 45% and 90%. The present study was designed to find any systematic difference between the methods. Nonsurgical and surgical retreatment was randomly assigned to 95 endodontically "failed" cases. The outcome of the procedures was clinically and radiographically recorded, and followed for 4 years. At the 12-month recall, a statistically significant (p < 0.05) higher healing rate was observed for cases surgically retreated. At the final 48-month examination, no such difference was found. These findings may be explained by (a) slower healing dynamics in the nonsurgical group and (b) the event of late "failures" in the surgical group. Within the latter category, four cases classified as healed after 1 yr failed at the final follow-up. Conclusively, this study failed to show any systematic difference in the outcome of surgical and nonsurgical endodontic retreatment. Surgical retreatment seems to result in more rapid periapical bone fill, but also may imply a higher risk of "late failures." From a scientific point of view, the length of the follow-up period is very important and may strongly influence the conclusions made.

Adolescent↗

PubMed1999

A comparative study of apical leakage of Apexit, Ketac-Endo, and Diaket root canal sealers.

The purpose of this study was to compare the apical leakage of Ketac-Endo, Apexit, and Diaket. Fifty freshly extracted human maxillary anterior teeth were used. The anatomical crowns were removed at the amelocemental junction, and step-back preparation of the roots canals was performed with K-type files to size 40 using 2 ml of 5.25% NaOCl irrigant after each file change. The roots were randomly divided into five groups of 10 roots each: three experimental and two control groups. The experimental groups were as follows: group 1, Apexit; group 2, Ketac-Endo; and group 3, Diaket. Root canals were filled with one of the sealers and gutta-percha using lateral condensation. After the specimens were stored in 100% humidity at 37 degrees C for 2 wk, the roots were covered with two layers of nail polish and immersed in 2% methylene blue for 7 days. Each tooth was split into two sections, and dye penetration was evaluated independently by three examiners using a stereomicroscope at x20 magnification. Mann-Whitney U analysis showed that there was no significant difference between Apexit and Diaket (p > 0.05). However, there was significantly more leakage with Ketac-Endo (p < 0.05).

Analysis of Variance↗

PubMed1999

Evaluation of apical seal in straight canals after obturation using the Lightspeed sectional method.

This study evaluated the sectional gutta-percha obturation technique advocated by Lightspeed Technology, Inc. Single relatively straight-canaled teeth were prepared with rotary instruments and divided into three groups. Groups A and B served as controls and were obturated using laterally condensed gutta-percha and either Roth's 801 or Ketac-Endo sealer. Group C was obturated using the Lightspeed technique that included placement of a 5-mm apical section of gutta-percha, followed by backfill with Ketac-Endo sealer and a single gutta-percha cone. All teeth were suspended in India ink for 14 days then cleared. Four additional teeth, which were obturated as in group C then sectioned, revealed a tightly adapted apical section of gutta-percha with a very thin layer of sealer. However, voids were noted in the middle and coronal areas. There was no significant difference in apical microleakage among the three groups. The sectional method was significantly faster than lateral condensation and seems to offer promise as an effective obturation method.

Chi-Square Distribution↗

PubMed1999

Apical canal diameter in the first upper molar at various ages.

The shape of root canals cross-sectioned through their roots at 2 mm from their apices and its correlation with the D0 diameter of endodontic instruments was evaluated in 40 first upper molars. The molars were grouped according to age: under 13 yr (children), 18 to 20 yr (adolescents), 30 to 40 yr (adults), and over 50 yr. Evaluation of the root canal diameters revealed that the shapes were predominantly circular in the palatal canal, mostly flat in the mesiobuccal canal, and circular or flat in equal proportions in the distobuccal root. Age does not seem to affect the shape of the canals. Narrowing with age was statistically significant (p < 0.05) for palatal and mesiobuccal canals only. Correlation between the maximum diameter of the canals and the instruments was varied. Even in old age, diameters were observed that would require instruments of a size that would be impossible to use, because one internal diameter would exceed the root's external diameter in a different direction (i.e. intimal buccolingual diameter of #80 and external mesiodistal diameter of #70).

Adolescent↗

PubMed1999

A comparative study of root-end induction using osteogenic protein-1, calcium hydroxide, and mineral trioxide aggregate in dogs.

Calcium hydroxide has been the material of choice for apexification. The purpose of this study was to compare the efficacy of osteogenic protein-1 and mineral trioxide aggregate with that of calcium hydroxide in the formation of hard tissue in immature roots of dogs. Sixty-four roots of premolars were used. After induction of periradicular lesions, the canals were debrided and filled with calcium hydroxide for 1 wk. After the removal of calcium hydroxide, the root canals received one of the treatment materials in a balanced design. The animals were euthanized 12 wk later. The degree of hard tissue formation and amount of inflammation were evaluated histomorphically. Data were statistically evaluated using ANOVA, chi 2, and Kruskal-Wallis. Mineral trioxide aggregate produced apical hard tissue formation with significantly greater consistency. The difference in the amount of hard tissue produced among the three test materials was not statistically significant. Furthermore, the degree of inflammation was not significantly different between the various test groups.

Aluminum Compounds↗

PubMed1999

Intraoral widening and lengthening of the mandible in baboons by distraction osteogenesis.

PURPOSE: The purpose of this study was to analyze the skeletal and dental positional changes and histomorphology of the distraction regenerates and mucogingival periosteal tissues that occurred after simultaneous widening and bilateral lengthening of the mandible in baboons by a miniaturized intraoral bone-borne distraction appliance. MATERIALS AND METHODS: Distraction appliances were activated 5 days after vertical ramus and symphyseal osteotomies at a rate of 0.9 mm/d for 10 days. The appliances were then stabilized for 8 weeks, after which the animals were killed. The distraction gaps and gingival tissues were analyzed clinically, histologically, and by standardized radiographic studies. RESULTS: Positional changes of the canines and incisor apices were proportional to the skeletal movements. Tipping of both incisors toward the center of the distraction gap was observed. Proportionate movement of the superior and inferior portion of the distracted segments was noted. Newly formed longitudinal trabecular columns parallel to the vector of distraction originated from the intact margins of alveolar bone contiguous with the adjacent teeth. Active histogenesis occurred in the stretched mucogingival periosteal tissues located in the distraction gaps. CONCLUSIONS: The results of this investigation support the clinical use of the miniaturized intraoral bone-borne distraction appliance to selectively widen and lengthen the mandible. The orientation of the mandibular distractors must be parallel to the common vector of distraction, which should be parallel to the maxillary occlusal plane. The formation of a bone regenerate in the alveolar region depends on the presence of an adequate bone interface on either side of the distraction gap.

Alveolar Process↗

PubMed1999

Are dental anomalies risk factors for apical root resorption in orthodontic patients?

Regression analyses suggest a weak prediction power of identified risk factors for apical root resorption in orthodontic patients, indicating the presence of etiologic or causative factors that have not yet been disclosed. To investigate the possible significance of dental anomalies as risk factors, pretreatment and posttreatment periapical radiographs of 84 patients with presence of at least one dental anomaly and of 84 patients without such anomalies were compared. The patients in the two groups were matched according to age, gender, Angle Class, extraction therapy, overbite, and treatment time. Apical root resorption was calculated by subtracting posttreatment tooth length measurements from the corresponding pretreatment measurements. Two sample t tests revealed no differences in mean root resorption between the patients in the two groups (P = .88). Stepwise regression analyses did not identify any of the individual anomalies as risk factors. In addition, patients with more than one anomaly did not appear to be at increased risk.

Adolescent↗

PubMed1998

Etiology and sequelae of root resorption.

This article reviews the current status of investigation into apical root resorption within the context of orthodontic treatment. Treatment and patient factors that have traditionally been investigated are discussed, along with the results of current research in this area. The need for rethinking traditional research strategies in the quest for identifying both control and causative mechanisms is explored. Finally, proposals for key areas of future interest are highlighted.

Animals↗