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Access Cavities (access + cavity)

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Medical Sciences	100%

Selected Abstracts

Effect of Aging on Coronal Microleakage in Access Cavities through Metal Ceramic Crowns Restored with Resin Composites

JOURNAL OF PROSTHODONTICS, Issue 5 2010
Ali Abdullah Alwan Al-Maqtari BDS
Abstract Purpose: The purpose of this in vitro study was to determine if packable resin composite with/without flowable resin composite has the ability to prevent coronal leakage in restored endodontic access openings following aging. Materials and Methods: Eighty simulated standardized access cavities of metal-ceramic crowns were fabricated and fixed on Vitrebond cavities filled with an epoxy resin. The specimens were randomly divided into two main groups: (1) Group A,Access cavities filled with only packable composite (Filtek P60); (2) Group B,Access cavities filled with Filtek P60 and a flowable composite (Filtek Z350) as liner. Each main group was further subdivided randomly into four subgroups according to water storage and thermocycling periods. All specimens were immersed in blue ink solution for 24 hours and then sectioned into quadrants. The extension of blue ink along the metal-ceramic crown/composite resin interface was measured linearly using image analyzer and then analyzed by three-way ANOVA and independent t -test with a Mann-Whitney test. The level of significance was set at p < 0.05. Results: All tested subgroups demonstrated different levels of microleakage. There was no significant difference related to restorative technique; however, there was a significant difference related to water storage and thermocycling. Conclusions: All tested techniques and materials in this study showed microleakage. Packable composite while a flowable liner showed a marginally better result than packable composite alone. Excessive thermocycling resulted in significant differences among the test groups. [source]

Root and canal morphology of permanent mandibular molars in a Sudanese population

INTERNATIONAL ENDODONTIC JOURNAL, Issue 10 2007
H. A. Ahmed
Abstract Aim, To investigate variations in the root canal systems of first and second permanent mandibular molar teeth in a Sudanese population using a clearing technique. Methodology, Two hundred extracted first and second permanent mandibular molars from three cities in the state of Khartoum were studied. Access cavities were prepared and pulp tissue was removed by immersion in 5% sodium hypochlorite under ultrasonication; Indian ink was then injected into the root canal systems assisted by a vacuum applied apically. The teeth were rendered clear by demineralization and immersion in methyl salicylate before evaluation. The following observations were made (i) number of roots and their morphology; (ii) number of root canals per tooth; (iii) number of root canals per root and (iv) root canal configuration. Results, Overall 59% of mandibular first molars had four canals with 3% having a third distolingual root. Seventy-eight per cent of second mandibular molars had two separate flat roots, whilst 10% were C-shaped. The most common canal system configurations were type IV (73%) and type II (14%). Inter-canal communications were more common in the mesial roots. The prevalence of inter-canal communications was 65% in first molars and 49% in second molars. Conclusions, In this sample of Sudanese teeth, 59% of the mandibular first permanent molars had four root canals whilst 10% of the mandibular second molars had C-shaped roots/canals. [source]

Assessment of a contrast medium as an adjunct to endodontic radiography

INTERNATIONAL ENDODONTIC JOURNAL, Issue 12 2004
J. M. Bedford
Abstract Aim, To assess if a contrast medium improved diagnostic yield of endodontic radiographs. Methodology, Forty-five extracted mandibular premolar teeth were radiographed in bucco-lingual and mesio-distal planes. Access cavities were prepared, pulpal tissue extirpated and Ultravist® contrast medium introduced under pressure. Radiographs were retaken and the teeth cleared following perfusion with India ink. Three examiners assessed all the films for: number of roots, number of root canals, curvature of root and/or root canal, presence of lateral canals, presence of a single foramen or apical delta and the presence or absence of canal obstructions. The examiners' interpretations were compared with the anatomy revealed by clearing. Results, Kappa scores were calculated for each of the examiners, for each set of radiographs, to assess the level of intra- and inter-examiner agreement. Only moderate agreement was found throughout (, = 0.40,0.61). For multiple root canals a false-positive result was significantly more likely with contrast (P < 0.05). The use of contrast did not significantly improve the sensitivity of diagnosis of lateral canals or a single apical foramen. Contrast significantly increased the risk of falsely perceiving lateral canals (P < 0.002). Overall there was no statistically significant difference in the overall assessment of the anatomy of the root canals using contrast or plain radiographs (P > 0.2). Conclusions, Plain film radiographs confidently predict the presence of root or canal curvature but apical anatomy was assessed accurately in only 46% of cases. Plain radiographs were insensitive in assessing the number of root canals present, the presence of lateral canals and the occurrence of canal obstructions. The use of Ultravist® contrast medium to improve diagnosis of root canal morphology of premolars is not supported. [source]

Light and scanning electron microscopic evaluation of GlydeÔ File Prep in smear layer removal

INTERNATIONAL ENDODONTIC JOURNAL, Issue 5 2003
T. S. Lim
Abstract Aim, To evaluate the effectiveness of GlydeÔ File Prep used in conjunction with sodium hypochlorite irrigation in the removal of smear layer produced during root canal instrumentation. Methodology, Thirty-nine extracted human teeth with single root canals were used. Access cavities were prepared and the teeth divided into three groups of 13 teeth each. Each group was treated by one of the three different regimes of irrigation and conditioning during root canal instrumentation. Group A: 0.5 mL of 1% NaOCl irrigation after each file size with an additional final irrigation of 10 mL 1% NaOCl; group B: 0.5 mL of 1% NaOCl irrigation after each file size with an additional final irrigation of 10 mL 17% EDTA; group C: GlydeÔ File Prep coated on each instrumentation file used in conjunction with 0.5 mL 1% NaOCl irrigation after each file size and an additional final irrigation of 10 mL 1% NaOCl. The teeth were then longitudinally grooved and sectioned. Root canal cleanliness was evaluated with the aid of a Nikon light microscope (×40 and ×100) and scanning electron microscope (×1000 and ×3000). The debris scores obtained at three canal regions were compared statistically within the same group and among different groups using repeated measurements of analysis of variance (anova) with Bonferroni adjustments and anova with posthoc Tukey HSD, respectively. Results, The canals treated with EDTA and GlydeÔ File Prep were significantly cleaner than those treated with NaOCl alone. The apical region of the root canals generally displayed more residual smear layer, but the difference was not significant. Conclusions, Used in conjunction with NaOCl irrigation, GlydeÔ File Prep was effective in removing smear layer produced during root canal instrumentation. [source]

Effect of traditional and alternative intracoronal bleaching agents on microhardness of human dentine

JOURNAL OF ORAL REHABILITATION, Issue 8 2004
H. K. Chng
summary, The purpose of this study was to compare the effect of traditional and alternative bleaching agents on microhardness of human dentine when used intracoronally. Thirty-six premolars were divided into six groups and bleaching agents were sealed into the pulp chambers as follows: group 1 , distilled water (control), group 2,30% hydrogen peroxide solution, group 3 , sodium perborate mixed with distilled water, group 4 , sodium perborate mixed with 30% hydrogen peroxide solution, group 5,35% carbamide peroxide gel, group 6,35% hydrogen peroxide gel. Access cavities were sealed and the teeth were stored in distilled water at 37°C. After 7 days, each tooth was sectioned at the cemento-enamel junction level and microhardness testing was carried out on dentine. The results showed that treatment with 35% hydrogen peroxide gel, 30% hydrogen peroxide solution and 35% carbamide peroxide gel reduced the microhardness of outer dentine to a small extent while treatment with sodium perborate mixed with water and sodium perborate mixed with 30% hydrogen peroxide solution did not significantly alter the microhardness of dentine. [source]

Effect of Aging on Coronal Microleakage in Access Cavities through Metal Ceramic Crowns Restored with Resin Composites

Micro-computed tomography of tooth tissue volume changes following endodontic procedures and post space preparation

INTERNATIONAL ENDODONTIC JOURNAL, Issue 12 2009
O. H. Ikram
Abstract Aim, To compare the volume of hard tooth tissue lost after caries removal, access cavity preparation, root canal preparation, fibre post space and cast post preparation in carious premolar teeth. The null hypothesis tested was that there is no difference between the volumes of hard tooth tissue lost expressed as a percentage of the preoperative hard tooth tissue volume, after each operative procedure. Methodology, Twelve extracted human premolars with mesial or distal carious cavities penetrating into the pulp chamber were selected. Teeth were scanned using a microCT scanner. After each operative procedure the loss of hard tooth tissue volume was measured. The data were statistically analysed using one-way analysis of variance and Fisher's PLSD test with statistical significance set at , = 0.01. Results, The percentage of preoperative hard tooth tissue volume lost after caries removal was 8.3 ± 5.83, after access cavity preparation the loss of volume reached 12.7 ± 6.7% (increase of 4.4%). After root canal preparation, fibre post space and cast post preparation the hard tissue volume lost reached, 13.7 ± 6.7 (increase of 1%), 15.1 ± 6.3 (increase of 1.4%) and 19.2 ± 7.4 (increase of 4.1%) respectively. Each procedure performed after caries removal significantly increased (P < 0.01) the amount of hard tissue volume lost with the exception of the root canal preparation. Conclusions, Access cavity and post space preparation are the procedures during root canal treatment which result in the largest loss of hard tooth tissue structure. Cast post space preparation causes a larger loss of tooth structure than fibre post space preparation. This should be taken into account when planning root canal treatment and restoration of root filled teeth that are to be restored with cuspal coverage restorations. [source]

Radicular peroxide penetration from carbamide peroxide gels during intracoronal bleaching

INTERNATIONAL ENDODONTIC JOURNAL, Issue 7 2008
O. Gökay
Abstract Aim, To evaluate and compare radicular peroxide diffusion from different concentrations of carbamide peroxide bleaching gels. Methodology, Fifty maxillary premolar teeth were separated into five groups (n = 10). Standardized endodontic access cavities were prepared in the occlusal surfaces, and the root canals were prepared using a step back technique and filled using the lateral compaction technique. The gutta-percha filling was removed 4 mm short of the cemento-enamel junction (CEJ) and a 2-mm-thick glass,ionomer cement base was placed. Outer root surfaces were sealed with wax and nail polish, leaving the coronal third of the tooth and the CEJ exposed. All teeth were immersed in a plastic tube containing 2 mL of distilled water, and the experimental groups were treated with a bleaching agent of either 10%, 17% or 37% carbamide peroxide (CP) or a mixture of 30% hydrogen peroxide (HP) and sodium perborate (SP) placed into the coronal pulp chamber of teeth and left for 24 h. Peroxide penetration was measured using the ferrothiocyanate method. Statistical analysis of data was conducted by using the Kruskal,Wallis Analysis of Variance and Mann,Whitney U test. Results, Higher peroxide penetration occurred with the 30% HP-SP mixture than with the CP bleaching gels, and the 37% CP group also promoted greater peroxide penetration than the other CP groups (P < 0.05). There was no statistically significant difference between 10% and 17% CP groups (P > 0.05). Conclusion, Peroxide penetration of CP gels was significantly lower than that of a HP-SP mixture. [source]

Histological evaluation of MTA as a root-end filling material

INTERNATIONAL ENDODONTIC JOURNAL, Issue 10 2007
P. F. E. Bernabé
Abstract Aim, To assess the histological response associated with grey mineral trioxide aggregate (GMTA) and zinc oxide eugenol (ZOE) as root-end filling materials in teeth where the root canals were not filled and the coronal access cavities were not restored. Methodology, Periapical lesions were developed in 24 premolar teeth in three dogs. The root canals were prepared and half of them were dried, filled and the coronal access restored (closed). The remaining teeth were not root filled and no coronal restoration was placed (open). Apical root-end resections were performed 3 mm from the apex, and root-end cavities were prepared with ultrasonic tips. These were randomly filled with either ZOE or GMTA in the same number of specimens using MAPSYSTEM device. After 180 days the animals were killed and blocks of tissues removed and processed for histological examination. Periradicular tissue reaction was evaluated, including severity of inflammation and cementum formation. Statistical analysis was performed using anova analysis and Tukey's test. Results, A significant difference was found between the levels of inflammation in the periradicular tissues of the GMTA/closed group, compared with the ZOE/open and ZOE/closed groups (P < 0.05) but not between GMTA/closed and GMTA/open groups. Cementum formation was not found over any ZOE specimens but over MTA in all specimens. No microorganisms were found in the interface between the material and the dentinal walls. Conclusions, GMTA was associated with less periapical inflammation and tissue response when used as a root-end filling material, even when no root filling or coronal restoration was present. [source]

Influence of cervical preflaring on apical file size determination

INTERNATIONAL ENDODONTIC JOURNAL, Issue 7 2005
J. D. Pecora
Abstract Aim, To investigate the influence of cervical preflaring with different instruments (Gates-Glidden drills, Quantec Flare series instruments and LA Axxess burs) on the first file that binds at working length (WL) in maxillary central incisors. Methodology, Forty human maxillary central incisors with complete root formation were used. After standard access cavities, a size 06 K-file was inserted into each canal until the apical foramen was reached. The WL was set 1 mm short of the apical foramen. Group 1 received the initial apical instrument without previous preflaring of the cervical and middle thirds of the root canal. Group 2 had the cervical and middle portion of the root canals enlarged with Gates-Glidden drills sizes 90, 110 and 130. Group 3 had the cervical and middle thirds of the root canals enlarged with nickel-titanium Quantec Flare series instruments. Titanium-nitrite treated, stainless steel LA Axxess burs were used for preflaring the cervical and middle portions of root canals from group 4. Each canal was sized using manual K-files, starting with size 08 files with passive movements until the WL was reached. File sizes were increased until a binding sensation was felt at the WL, and the instrument size was recorded for each tooth. The apical region was then observed under a stereoscopic magnifier, images were recorded digitally and the differences between root canal and maximum file diameters were evaluated for each sample. Results, Significant differences were found between experimental groups regarding anatomical diameter at the WL and the first file to bind in the canal (P < 0.01, 95% confidence interval). The major discrepancy was found when no preflaring was performed (0.151 mm average). The LA Axxess burs produced the smallest differences between anatomical diameter and first file to bind (0.016 mm average). Gates-Glidden drills and Flare instruments were ranked in an intermediary position, with no statistically significant differences between them (0.093 mm average). Conclusions, The instrument binding technique for determining anatomical diameter at WL is not precise. Preflaring of the cervical and middle thirds of the root canal improved anatomical diameter determination; the instrument used for preflaring played a major role in determining the anatomical diameter at the WL. Canals preflared with LA Axxess burs created a more accurate relationship between file size and anatomical diameter. [source]

An in vitro investigation of the bulk flow of fluid through apical foramina during simulated tooth extraction: a potential confounder in microbiological studies?

INTERNATIONAL ENDODONTIC JOURNAL, Issue 4 2001
A. Kapalas
Aim,The ,pumping action' induced during tooth extraction may cause bacteria suspended in tissue fluids to be transposed from one anatomical compartment to another. Apart from causing bacteraemia, this may lead to inaccuracies in studies evaluating the presence and distribution of bacteria in and around tooth apices. The aim was to investigate the bulk flow of fluid through apical foramina during simulated extraction of teeth in an in vitro model. The influence of the presence or absence of a coronal restoration was also evaluated. Methodology,Twenty extracted single-rooted, human, mature, permanent teeth were used. Standard access cavities were prepared and the root canals located. Standardized micrographs of the apical foramina were obtained and their area (µm2) was calculated by image analysis software. The teeth were then set and sealed into polyvinylsiloxane (rubber base) impression material. Crystal violet dye was inoculated into the coronal half of the root canal system. Tooth extraction movements were simulated in the impression matrix and the leakage of dyes with and without the presence of a coronal restoration was examined. The procedure was repeated, following application of safranin dye in a coronal trough within the simulated rubber base gingival margin at the CEJ. The results were analysed statistically with the independent-samples t -test and the McNemar test. Results,In the absence of a coronal restoration crystal violet leaked out of the apical foramina in 18/20 teeth; conversely safranin leaked into the teeth through the apical foramina in 11/20 cases when applied to the external root surface. In the presence of an intact coronal restoration crystal violet dye leaked out in 6/20 teeth and conversely safranin leaked into 7/20 teeth. The presence of a coronal restoration significantly reduced (P = 0.002) dye leakage out of the root canal system. No associations were found for leakage of dye into the root canal system when applied externally. In addition, the amount of dye leakage was positively correlated with the area of the apical foramen in the presence of a coronal restoration (P = 0.009). Conclusion,The presence of a coronal restoration significantly reduced leakage of dye out of the apical foramen. Microbiological studies on root canals and periapical lesions using extracted teeth should take potential contamination from this source into account. [source]

Effect of access cavity location and design on degree and distribution of instrumented root canal surface in maxillary anterior teeth

INTERNATIONAL ENDODONTIC JOURNAL, Issue 3 2001
G. Mannan
Abstract Aim The null hypothesis tested in this study was that in single-rooted anterior teeth with simple root canal anatomy, different access cavity designs (,lingual cingulum', ,lingual conventional', ,incisal straight-line') do not influence the ability of endodontic files to plane the walls of the root canals. Methodology, Thirty extracted human maxillary anterior teeth were divided randomly into three groups for each access cavity. The access cavities were prepared according to predefined criteria and the roots embedded in individual polyvinyl-siloxane putty matrices. The matrices allowed these teeth to be split into buccal and palatal halves and to be reassembled. The split teeth enabled removal of pulpal remnants from the root canal system and the walls to be stained with an even layer of permanent black ink. Once dried, the split roots were reassembled in the putty matrices and a step-back filing technique was used to prepare the canals with water irrigation. The canal walls were examined for residual ink staining and scored by three independent assessors using an index devised for the purpose. Results There was good agreement between the assessors. None of the access cavities allowed file contact with the entire root canal wall. The overall (palatal and buccal sections) scores showed significant differences (P < 0.01) between the access cavity groups in the extent to which the canal walls could be filed. The straight-line incisal access cavity had the greatest proportion of instrumented root canal surface. The lingual cingulum access cavity was the worst in this respect. The differences in residual ink scores between the access cavity types were significant for the buccal halves (P < 0.01) but not for the palatal halves (P > 0.05). Conclusions The null hypothesis was proven. Regardless of access cavity design, mechanical preparation did not allow instrumentation of the entire root canal wall. Straight-line access allowed the greatest proportion of the root canal wall to be instrumented and the lingual cingulum access the least. [source]

Effect of Aging on Coronal Microleakage in Access Cavities through Metal Ceramic Crowns Restored with Resin Composites

In vitro evaluation of the accuracy of five different electronic apex locators for determining the working length of endodontically retreated teeth

AUSTRALIAN ENDODONTIC JOURNAL, Issue 1 2007
Aqeel Khalil Ebrahim bds
Abstract The aim of this study was to evaluate the accuracy of five electronic apex locators (EALs) in determining the working length (WL) of teeth after removal of the root canal obturation materials. A total of 32 extracted straight, single-rooted teeth were used. The actual canal length (AL) was determined and the WL was established by subtracting 0.5 mm from the AL. The root canals were instrumented and divided into two groups. One group (n = 6) served as control, while the other group (n = 26) was the experimental group. In the experimental group, the root canals were obturated using vertically compacted gutta-percha with AH 26 sealer. In both groups, the access cavities were restored with a provisional restoration and stored for 15 days at 37°C and 100% humidity. The root canal obturation material was removed, and the teeth were then mounted in an experimental apparatus. Five EALs were used: Dentaport ZXTM®, ProPex, Foramatron D10, Apex NRG and Apit 7. For the electronic measurement of canal length, a size 25 K-file was used. During measurement, the canal was irrigated with 2.5% sodium hypochlorite. The difference (D) between the AL and the electronically determined length (EDL), AL,EDL, was calculated and recorded for each measurement. Data were analysed by two-way anova and Fisher's PLSD test. In both groups, statistically significant differences were found among the EALs (P < 0.01). In conclusion, the Dentaport ZXTM®, ProPex and Foramatron D10 were more accurate than the other two EALs in determining the WL in teeth after removal of the root canal obturation materials. However, the Apex NRG and Apit 7 were also reliable for determination of the WL in the majority of the cases. [source]

Apexogenesis after initial root canal treatment of an immature maxillary incisor , a case report

INTERNATIONAL ENDODONTIC JOURNAL, Issue 1 2010
S. R. Kvinnsland
Abstract Aim, To present a case where a traumatized, immature tooth still showed capacity for continued root development and apexogenesis after root canal treatment was initiated based on an inaccurate pulpal diagnosis. Summary, Traumatic dental injuries may result in endodontic complications. Treatment strategies for traumatized, immature teeth should aim at preserving pulp vitality to ensure further root development and tooth maturation. A 9-year-old boy, who had suffered a concussion injury to the maxillary anterior teeth, was referred after endodontic treatment was initiated in tooth 21 one week earlier. The tooth had incomplete root length, thin dentinal walls and a wide open apex. The pulp chamber had been accessed, and the pulp canal instrumented to size 100. According to the referral, bleeding from the root made it difficult to fill the root canal with calcium hydroxide. No radiographic signs of apical breakdown were recorded. Based on radiographic and clinical findings, a conservative treatment approach was followed to allow continued root development. Follow-up with radiographic examination every 3rd month was performed for 15 months. Continued root formation with apical closure was recorded. In the cervical area, a hard tissue barrier developed, which was sealed with white mineral trioxide aggregate (MTA). Bonded composite was used to seal the access cavity. At the final 2 years follow-up, the tooth showed further root development and was free from symptoms. Key learning points, ,,Endodontic treatment of immature teeth may result in a poor long-term prognosis. ,,The pulp of immature teeth has a significant repair potential as long as infection is prevented. ,,Treatment strategies of traumatized, immature permanent teeth should aim at preserving pulp vitality to secure further root development and tooth maturation. ,,Radiographic interpretation of the periapical area of immature teeth may be confused by the un-mineralized radiolucent zone surrounding the dental papilla. [source]

Anatomic Endodontic Technology (AET) , a crown-down root canal preparation technique: basic concepts, operative procedure and instruments

INTERNATIONAL ENDODONTIC JOURNAL, Issue 8 2005
F. Riitano
Abstract Aim, To illustrate the conceptual basis and the operative procedure of the Anatomic Endodontic TechnologyTM (AET) technique and to illustrate the specific instruments used in each phase. Summary, The basic characteristics of the AETTM technique are reported. The instruments and procedure are described in three phases: coronal access, coronal-middle preparation and apical preparation. In the first phase, correct cavity design is described. In the coronal-middle phase, the use of four stainless steel shaping instruments, powered by a reciprocating handpiece is described, incorporating a brushing-milling action against canal walls. During the apical phase, dedicated apical stainless steel and NiTi hand instruments are used to complete the preparation. The stainless steel apical files are used with a 1/4 turn and withdrawal movement whilst the NiTi are used in 360° rotary motion. Key learning points ,,Most current canal shaping techniques do not prepare all the canal walls and can result in over-enlargement in some areas. ,,AETTM defines three regions of the canal: coronal (from the cavo-surface of the access cavity), coronal-middle, and apical. ,,Coronal-middle instrumentation is undertaken with four mechanically driven stainless steel shaping instrument used in brushing-milling action against canal walls. ,,Apical preparation is completed by hand and with the formation of a stop. [source]