Dental Pulp Cavity

A mandibular first molar with more than four canals is an interesting example of anatomic variations, especially when four of these canals are located in distal roots. This report describes a case of a mandibular first molar with six canals (two mesial and four distal canals in two distal roots). The canals were equipped with a K-file and irrigated with NaOCl (5.25%) and normal saline as the final irrigant. The canals were filled laterally with gutta percha and AH26 sealer (De Trey, Dentsply, Switzerland). This case shows a rare anatomic configuration and points out the importance of looking for additional canals.

The main issue to be faced to get size estimates of 3D modification of the dental canal after endodontic treatment is the co-registration of the image stacks obtained through micro computed tomography (micro-CT) scans before and after treatment. Here quantitative analysis of micro-CT images have been performed by means of new dedicated software targeted to the analysis of root canal after endodontic instrumentation. This software analytically calculates the best superposition between the pre and post structures using the inertia tensor of the tooth. This strategy avoid minimization procedures, which can be user dependent, and time consuming. Once the co-registration have been achieved dimensional measurements have then been performed by contemporary evaluation of quantitative parameters over the two superimposed stacks of micro-CT images. The software automatically calculated the changes of volume, surface and symmetry axes in 3D occurring after the instrumentation. The calculation ...

There are various techniques to study root canal morphology and diaphonization is one of them. There are various methods of decalcification and diaphonization, cited in literature and the main aim of this paper was to give a brief account of the various techniques and share our experience of the technique at a teaching institution in Karachi, Pakistan. Diaphonization is one of the oldest methods and is based on decalcification of teeth followed by clearing and dye penetration. The specimen is later studied under microscope without sectioning. After the process of clearing a three-dimensional (3D) structure of the internal canal anatomy was visible with naked eye. This paper entails a detailed historical background as well as the author's technique including percentages of various chemicals used and the timing of immersion of teeth into these agents. The read out is simple and can be subjected to interpretation by direct observation under microscope and can be helpful for student...

The aim of this study was to evaluate in vitro a possible mechanism involved in the antimicrobial action of calcium hydroxide, namely absorption of carbon dioxide from the roof canal.Twenty obligate and 20 facultative anaerobic bacteria isolated from infected root canals and identified to species level were used. For each bacterial species a standard concentration was achieved and 0.1 ml of the inoculum was spread on blood agar plates, which were consecutively incubated in an anaerobic chamber for 5–7 days.One experimental and one control group were studied: the experimental group included one plate with the bacterial species as well as one open plate containing 32 g calcium hydroxide paste at a mixing ratio of 6:4. Both plates were incubated in an anaerobic chamber for 72 h. The control group included only one plate containing the same bacterial species and was incubated under the same conditions. After a 72-h incubation, the number of the recovered bacteria were counted in both groups.Statistical analysis showed that the number of bacteria recovered from the control group was significantly lower than that of the experimental group, but no particular resistance of any bacterial species to calcium hydroxide could be detected. This finding strongly suggests that the ability of calcium hydroxide to absorb carbon dioxide may contribute to its antibacterial activity.

A radiographic recall evaluation of 894 endodontic cases treated by dental students at the University of Oklahoma College of Dentistry was conducted by faculty. The purpose of this study was to determine the success of standardized nonsurgical endodontic treatments by using radiographic techniques of determination and to compare the results to similar studies at other dental schools. Cases were labeled as successful, acceptable, questionable, and failing. Observations included time since treatment, age, gender, and tooth type. The combined percentage of successful and acceptable cases was 91.05%. Differences in percentage of success among recall time intervals were statistically significant (p < 0.01), as were the percentages of success between tooth types treated (p < 0.05). Success rate was not affected by age or gender (p > 0.05). The overall rate of successful and acceptable cases in this study was found to compare favorably with those from recall studies conducted at o...

To evaluate in a clinical case series the location of fractured instruments, how many of them could be removed and to compare these findings with the results of a similar study. Within an 18-month period all referred endodontic cases involving fractured instruments within root canals were analysed. The protocol for removal of fractured instruments was: create straight-line access to the coronal portion of the fractured instrument, attempt to create a ditched groove around the coronal aspect of the instrument using ultrasonic files and/or to bypass it with K-Files. Subsequently, the fractured instrument was vibrated ultrasonically and flushed out of the root canal or an attempt was made to remove the instrument with the Tube-and-Hedström file-Method or similar techniques. The location of the fractured instrument and the time required for removal were recorded. Successful removal was defined as complete removal from the root canal without creating a clinically detectable perforation. In total, 97 consecutive cases of instrument fracture were included in the time period. In all, 84 instruments (87%) were removed successfully. There was a significant correlation between the time needed to remove fractured instruments and a decrease in success rate. Curved canals had significantly more fractured instruments than straight canals (P < 0.05). Rotary instruments fractured significantly more often in curved canals (P < 0.05) compared with other instruments. Half of all instrument fractures occurred in mesial roots of lower molars and most often when using rotating instruments. There was no statistically significant difference in the success rate with respect to the location of the fractured instrument (tooth/root type), the type of fractured instrument or the different methods of instrument removal. Curved canals are a higher risk for instrument fracture than straight canals. In curved canals rotary instruments (including lentulo spirals) fractured more often than other instruments. In all, 87% of the fractured instruments were removed successfully. A decrease in success rate was evident with increasing treatment time. The use of an operating microscope was a prerequisite for the techniques used to remove the fractured instruments.

The purpose of this study was to compare pulpal and periapical tissue reactions to electrosurgery versus formocresol pulpotomy techniques in the primary teeth of dogs. The study was conducted on 33 primary teeth of three mongrel dogs between the ages of one to three months. Each dog had three teeth treated by Formocresol Pulpotomy with Mechanical Coronal Pulp Removal (FC), three teeth treated by Electrosurgery Pulpotomy with Mechanical Coronal Pulp Removal (ES/MCPR), three teeth treated by Electrosurgery Pulpotomy with Electrosurgical Coronal Pulp Removal (ES/ECPR), and two teeth serving as untreated Controls. Dogs one, two and three were sacrificed performing the pulpotomies at two, four and six weeks, respectively. The pulp, periapical tissue and after surrounding bone were submitted to histological examination and the histological reaction was recorded. The results were fourteen out of 18 unfavorable and zero out of three favorable histological reactions occurred in the FC treate...

Aim To investigate the attitudes of general dental practitioners (GDPs) and endodontists in the UK towards management of fractured endodontic instruments.Methodology A questionnaire was sent to 330 systemically selected GDPs and all endodontists working in the UK (170). It was accompanied by a covering letter explaining the aims of the study and indicating that all the information given would remain confidential. Those who did not respond to the first mailing were sent another two mailings. Data were analysed using chi-square test at P ≤ 0.05.Results The overall response rate was 75%. Only 18.5% of respondents reported that they would retrieve instruments located in the apical third of root canals with a significantly higher proportion of endodontists (25.9%) compared with that of GDPs (14%) doing so. A significantly higher proportion of endodontists (98.5%) used ultrasonics for removal of fractured instruments compared with GDPs (75.8%). The most common complication of fractured instrument retrieval was thought to be excessive removal of dentine (67%). The majority of respondents (88.5%) reported that they would leave the unsuccessfully removed file in situ and obturate the root canal.Conclusion Both endodontists and GDPs were aware of the limitations of root canal anatomy when removal of fractured instruments was considered. Excessive removal of dentine, the most common complication associated with the removal process, suggests the need for more conservative techniques. Both endodontists and GDPs demonstrated a conservative approach when management of fractured instruments failed. Further studies regarding attitudes of GDPs and endodontists towards some specific aspects of fractured instruments management are required.

To evaluate the incidence of dentinal microcracks formation after root canal shaping procedures with HyFlex EDM and Vortex Blue rotary systems comparing with that of hand instrumentation using micro-computed tomography. Mandibular first molar teeth (n=60) having 50 to 200mesial root curvature were scanned using high resolution micro-CT imaging before root canal preparation to identify the presence of dentinal defects. Post-instrumentation cross-sectional images were taken and increased number and type of root defects were assessed and recorded. The data was statistically analysed by using chi-square test and McNemar's test at a significance level of 5%. HyFlex EDM has shown greater increase in post instrumentation dentinal defects. Both rotary systems exhibited increased dentinal defects formation at coronal, middle regions which is statistically significant (P=0.042) when compared to apical region. HyFlex EDM has shown greater increase in post instrumentation dentinal defects f...

The cross-sectional canal morphology and minimum widths of buccal and lingual canal walls were studied in 20 mandibular molars with C-shaped roots and canal orifices. The roots were mounted in clear resin blocks and sectioned transversely at 1-mm intervals. A total of 154 cross-sections were evaluated with an image analyzer. Twelve different longitudinal canal configurations were identified. The most prevalent were types 1-2 and 1-2-1 with each type occurring in four roots. Evaluation of the cross-sectional morphology showed that the configurations were complete "C" (27), incomplete C (64), and non-C (9). The mean value for the minimum width of the lingual canal wall was 0.58 ± 0.21 mm and the buccal wall was 0.96 ± 0.26 mm. This suggests that there is a higher risk of root perforation at the thinner lingual walls of C-shaped canals during shaping and post canal preparation procedures. Both buccal and lingual canal walls were frequently narrower at mesial locations.

The aim of this study was to examine the prevalence of C. albicans in the oral cavities and root canals of children. Twenty healthy and caries-free children and 13 children with caries, were screened. Imprint samples and sterile paper points were used to obtain the samples from oral cavities and root canals respectively. The production of germ tubes and the development of chlamydospores identified yeast cultures. Sixty-nine percent of children with caries and 5% of caries-free children were found to be Candida carriers. The difference in candidal prevalence between two groups was significant (p < 0.05). Sixty-one point five percent of children were positive for Candida in the root canal. Since, increase in the C. albicans in the oral cavity provides a potential source of the fungus particularly when resistance falls below a certain threshold, attention to strategies for the reduction of this pervasive and persistent pathogen becomes important. Therefore, reduction of caries and o...