The effect of formalin storage on the apical microleakage of obturated canals

Awareness, Attitude and Practice Regarding Disinfection and Handling of Extracted Teeth among the Students in a Dental College in India

Objective:

The main objective of this study is to assess about the awareness, attitude, and practice regarding disinfection and handling of extracted teeth among the students of a dental college in Odisha, India.

Materials and Methods:

The survey was done with a self-designed questionnaire distributed among the students of a dental college in Odisha, India. Data analysis was done using the Statistical Package for the Social Sciences Software (SPSS for Windows, Version 16.0., Released 2007, Chicago, SPSS Inc.) and the results obtained.

Results:

Of the many methods available, the safest and practical methods to sterilize and disinfect the extracted human teeth could be autoclaving, submersion in 10% formalin and 5.25% sodium hypochlorite solutions. In addition, it was found that there is a significant need to educate the potential handlers of such extracted teeth about the latest statuary protocol and guidelines.

Conclusion:

Most of the participants in the study were aware of the established safety protocols regarding how to handle the pathogenic specimens and were putting in practice those standardized guidelines. But still another good number of handlers need to change their casual attitude while following the safety guidelines so as to protect themselves, others and the environment from the pathogenic clinical specimens.

Awareness and Knowledge of Undergraduate Dental Students about Sterilization/Disinfection Methods of Extracted Human Teeth

BACKGROUND

Dental undergraduate students work on extracted human teeth in preclinical practical's to learn technical skills before entering the clinics and delivering dental care to the patients.

AIM

The aim of the present investigation was to assess the awareness and knowledge toward sterilization/disinfection methods of extracted human teeth in a selected group of Indian dental students.

MATERIALS AND METHODS

In this descriptive cross-sectional study, the participants consisted of 2^nd-, 3^rd-, 4^th-, and 5^th-year dental students. Data were collected by questionnaires and analyzed by Mann-Whitney U-test and Kruskal-Wallis test using SPSS software version 16 for Windows (SPSS Inc., Chicago, IL, USA).

RESULTS

In this study, 235 dental students participated in the study. The average awareness and knowledge score was 7.27 (1.92). Based on the opinion of 57% (134/235) students, hydrogen peroxide was selected as the suitable material for sterilization and 24.6% (58/235) students believed that autoclave sterilization is a good way for the purpose.

CONCLUSION

The results of this investigation indicated that awareness and knowledge of undergraduate dental students in relation to sterilization/disinfection methods of extracted human teeth were good. However, deficiencies were observed in relation to teaching the material and methods suitable for sterilization.

The effect of protocol for disinfection of extracted teeth recommended by center for disease control (CDC) on microhardness of enamel and dentin

Background

According to the guideline of the United States center for disease control (CDC), the extracted teeth should be sterilized by autoclaving or storage in 10% formalin before using for educational or research purposes. The objective of this study was to evaluate the effect of this protocol on microhardness of dentin and enamel.

Material and Methods

Thirty extracted single-root teeth were used in this study. The crowns were resected, and the roots were longitudinally sectioned into two halves. The Vickers microhardness (VHN) of specimens was measured on polished canal dentin and buccal enamel surfaces. The crowns were randomly divided into three groups (n=10). Group 1 and 2 were sterilized using autoclave and formalin, respectively while group 3 (control) was stored in synthetic tissue fluid. The root halves were also randomly divided into 3 groups (n=20) which were treated as mentioned above for crown samples. Following sterilization, VHN of samples was measured again. ANOVA and paired samples t-tests were used to analyze the data.

Results

Autoclaving caused a significant reduction in microhardness of dentin (P <0.001, 12.04% decreases in VHN). However, there were no significant differences for before and after sterilization within other groups.

Conclusions

Based on the results of this study, the CDC protocol is recommended in studies related to enamel microhardness. However, Autoclaving is not an appropriate sterilization method in studies related to dentin microhardness. In these studies, two-week immersion in 10% formalin is recommended.

Key words:Autoclave, CDC, extracted teeth, formalin, microhardness, sterilization.

Comparative analysis of the effect of autoclaving and 10% formalin storage on extracted teeth: A microleakage evaluation

Aim:

This study compares the effect of formalin and autoclaving the tooth samples by evaluating microleakage in-vitro.

Materials and Methods:

Forty-five extracted human permanent incisor teeth were taken and randomly divided into three groups (with different methods of storage and disinfection) with 15 teeth each: Group 1: Control-extracted teeth in this group were stored in normal saline, Group 2: the extracted teeth in this group were stored in 10 % formalin for two weeks and Group 3: the extracted teeth were Autoclaved at 121°C, at 15 psi pressure for 40 minutes. In all the groups after the specified storage period, class V cavities were prepared on the labial surface and restoration was performed with Z100 restorative. Finished and polished samples were subjected to 500 cycles of thermocycling. All specimens were immersed in methylene blue for 24 hours. After sectioning, the margins of restoration were evaluated for dye leakage at 10 X magnification, using an optical microscope. Data were subjected to nonparametric Kruskal Wallis one way analysis of variance. Inter-group comparisons were performed using the Mann Whitney test (P < 0.05).

Results:

The authors found that the microleakage in the formalin group was considerably lower than that in the control group. The autoclave group showed slightly higher mean microleakage, but the difference was not statistically significant.

Conclusion:

Both autoclaving and formalin storage affect, to a varying degree, the microleakage values in vitro. The results in the autoclaving group matched those of the control group more closely, with only a slight difference.

Sealing ability, marginal adaptation and their correlation using three root-end filling materials as apical plugs

Objective

This study used dye leakage assay and scanning electron microscopy to evaluate, respectively, the sealing ability and marginal adaptation of three root-end filling materials used as apical plugs, as well as the possible correlation between these properties.

Material and Methods

Ninety-eight single-rooted human teeth were prepared to simulate an open apex. The teeth were allocated to three experimental groups (n = 30), which received a 5-mm thick apical plug of (1) gray MTA Angelus^TM, (2) CPM^TM and (3) MBPc, and two controls groups (n = 4). After immersion in 0.2% Rhodamine B solution for 48 h, the teeth were sectioned longitudinally and analyzed by Image Tool 3.0 software. The marginal adaptation between apical plugs and the root canal walls were analyzed by SEM.

Results

MBPc had significantly less (p<0.05) apical leakage than the other materials. Regarding marginal adaptation, CPM^TM showed the best numerical results, though without statistical significance from the other materials (p<0.05). There was no correlation between the two properties.

Conclusions

When used as apical plugs, the tested root-end filling materials had similar marginal adaptation to the dentin walls, but MBPc had the best sealing ability, as demonstrated by the least apical leakage from all tested materials.

Chronologic comparison of root dentin moisture in extracted human teeth stored in formalin, sodium azide, and distilled water

This study quantified in vitro the root dentin moisture when 10% formalin (group A), 3% sodium azide (group B), and distilled water (group C) were used as teeth storage media. The root dentin moisture of 66 extracted human mandibular single-rooted teeth was measured at baseline (day 0) and at 1, 3, 7, and 14 days using a digital grain moisture meter. The baseline dentin moisture value was used as covariate in the generalized estimating equation (GEE) analysis. The mean dentin moisture values (%) +/- SD on days 0, 1, 3, 7, and 14 were, respectively: 10.6 +/- 0.64, 14.3 +/- 0.71, 14.6 +/- 0.84, 14.4 +/- 0.64, and 14.7 +/- 0.75 in group A; 11.4 +/- 0.94, 14.6 +/- 0.95, 14.6 +/- 0.76, 14.6 +/- 0.93, and 14.8 +/- 0.81 in group B; and 10.2 +/- 0.95, 12.8 +/- 0.90, 13.3 +/- 0.95, 13.0 +/- 0.91, and 13.2 +/- 0.89 in group C. The dentin moisture increased in all 3 groups; however, there was no overall significant difference in moisture between the formalin and sodium azide groups.

Apical Leakage of Root-End Placed SuperEBA, MTA, and Geristore Restorations in Human Teeth Previously Stored in 10% Formalin

The purpose of this study was to determine if storage of extracted teeth in 10% formalin affects microleakage of MTA, Geristore, or SuperEBA root-end fillings. There were 130 freshly extracted single-rooted teeth collected, immediately placed in phosphate buffered saline (PBS) and stored for less than 24 hours. Teeth were divided and either placed in 10% formalin for a 4-weeks immersion or immediately prepared. Preparation for all teeth consisted of canal instrumentation, obturation, apical resection, retrograde preparation, and placement of a root-end filling material. After 72 hours, the apical portions were immersed in India ink under vacuum pressure for 30 minutes, and then stored in ink for 1 week. Negative controls and positive controls performed as expected. In general, there was significantly less dye leakage of root-end restorations in teeth stored in 10% formalin when compared to the freshly extracted teeth (p < 0.0001). No difference in dye leakage was observed between Geristore restorations placed in teeth stored in formalin as compared to fresh teeth (p = 0.892). Less dye leakage was noted in teeth restored with Geristore as compared to MTA and SuperEBA, regardless of storage medium (p < 0.0001). No difference was observed between MTA and SuperEBA root-end restorations (p = 0.157). The results of this study provide evidence that storage of teeth in 10% formalin over a 4-week period may significantly influence dye leakage as compared to leakage in freshly extracted teeth.