Evaluation of dentinal crack propagation, amount of gutta percha remaining and time required during removal of gutta percha using two different rotary instruments and hand instruments - An In vitro study

Background

One of the most important goal of non surgical endodontic retreatment is the successful removal of gutta percha and sealers from the root canal system. A variety of techniques have been recommended for retreatment procedures for the removal of gutta-percha and sealers with or without the help of adjunctive chemical solvents, by using stainless steel hand files or nickel-titanium rotary files, gate glidden burs, heated instruments, ultrasonic instruments, and lasers 1,3. The current advancements in the design of NiTi instruments have proved efficacious in the removal of filling materials from the root canal wall and various studies have also confirmed their cleaning ability and efficacy 4,5. Nevertheless, the use of rotary instrumentation can lead to the formation of dentinal cracks in the root canal dentin. Many researchers have reported the incidence of crack formation and propagation after the procedure with manual, rotary and reciprocating instruments. The behavior of rotary instruments in the generation of defects have been the point of greatest interest during many years 6. These dentinal cracks can be defined as defects with a complete crack line extending from inner root canal space up to the outer surface of the root when the tensile stress in the root canal wall exceeds the tensile stress of dentin 7.

Aim

This study was conducted to investigate and to compare the amount of dentinal microcracks formation with various new instrumentation methods and conventional hand filing method. It also looks into amount of gutta-percha removed after retreatment from the canal and the time required for all the instrumentation technique.

Methodology

Sixty extracted human maxillary first molars with curved roots were mounted on addition silicone impression material incorporated in an aluminium hollow block, then instrumented using step-back preparation with 35 size K files. Obturation was done using gutta-percha with AH plus sealer. These were stored for 14 days and divided into three groups Mani GPR, Endostar Re Endo and H file and were subjected to retreatment procedures. Retreatment was considered complete when no filling material was observed on the canal wall and the canal was smooth and free of visible debris. The samples were examined under scanning electron microscope and the number of cracks were calculated. The percentage of root canal filling material and time taken was recorded.

Statistical Analysis

The data obtained were analyzed by using descriptive statistics, ANOVA (Analysis of Variance), chi-square test and Scheffe's post hoc test through SPSS for window (version 22.0).

Result

All the techniques showed similar amount of crack propagation, with no statistical difference between the group. Retreatment done using H Files required more time and removed less material. The coronal third showed less amount of gutta-percha remnants than the apical third in all groups.

Conclusion

All the groups showed a similar amount of crack propagation. Less number of cracks were observed in the coronal one third and more amount of cracks were found at the apical third. Endostar RE Endo rotary instrument proved to be most effective and least time-consuming. Hedstrom Files required more time and removed less material.

Prevalence of urinary tract infection and renal scars in patients with diabetes mellitus

In a case control study, we assessed the prevalence of bacterial urinary tract infections (UTI) and renal scarring in 155 consecutive type 1 (n=102) and type 2 (n=53) diabetic individuals and 128 healthy controls. Subjects who received antibiotics during the past 6 months, pregnant women and those with overt renal failure were excluded. In all subjects, urine culture and 99m Technetium (Tc) dimercapto-succinic acid renal scan was performed. UTI was diagnosed if two consecutive urine cultures grew the same organism with at least 10(5) colony forming unit (cfu)/ml in asymptomatic and at least 10(4) cfu/ml in symptomatic subjects, respectively. Renal scan was considered abnormal if focal or multiple tracer uptake defects and/or break in cortical outline were observed. The prevalence of UTI in diabetes mellitus was higher, when compared to that in controls (9% vs. 0.78%, P=0.005). Escherichia coli was the most commonly grown organism (64.3%), followed by Staphyloccocus aureus (21.4%) and Klebsiella pneumoniae (14.3%). Prevalence of renal scarring was higher in patients with diabetes (28/155, 18.0%), when compared to that of controls (7/128, 5.4%, P=0.002). Fifty percent of patients with diabetes and UTI had renal scarring. The prevalence in diabetics with no UTI was also higher, when compared to controls (14.8 vs. 5.5%, P<0.01). The prevalence of UTI as well as renal scarring was significantly higher in females, when compared to male diabetics. No significant difference in vascular events, hypertension, proteinuria, renal function tests and HbA1 was observed in patients with and without renal scar. Thus, patients with diabetes mellitus have 10- and 3-folds increased risk of UTI and renal scarring, respectively. The results could help prioritize protocols for management of UTI among patients with diabetes mellitus.

Species-specific prevalence of vaginal candidiasis among patients with diabetes mellitus and its relation to their glycaemic status

OBJECTIVES

Non- C. albicans Candida species are increasingly being recognized as the cause of vulvo-vaginal candidiasis. These species are often less susceptible to antifungal agents. Patients with diabetes mellitus are at risk for vulvo-vaginal candidasis. We assessed the species-specific prevalence rate and risk of candidiasis in patients with diabetes mellitus and healthy controls.

METHODS

Genital tract examination, direct microscopy and fungal cultures of discharge collected by high vaginal swab were undertaken among 78 consecutive patients with diabetes mellitus (mean (+/-sd) age 32+/-12 years and body mass index (BMI) 22.3+/-5.5kg/m(2)) and 88 age- and BMI-matched healthy females. Glycaemic control in the diabetic cohort was assessed by measuring total glycosylated haemoglobin.

RESULTS

Candida species were isolated in 36 of 78 (46%) subjects with diabetes mellitus and in 21 of 88 (23%) healthy subjects (Chi-squared 9.11, P=0.0025). The predominant Candida species isolated in diabetics with vulvo-vaginal candidiasis were Candida glabrata (39%), C. albicans (26%) and C. tropicalis (17%). In contrast, in the control group, C. albicans, C. glabrata and C. hemulonii comprised 30% each, with none having C. tropicalis infection (for C. tropicalis: diabetic vs. control; 17% vs. nil, P=0. 05). Among the diabetic group, subjects with vulvo-vaginal candidiasis had significantly higher mean HbA1 when compared to those who had no such infection (12.8+/-2.6% vs. 9.7+/-1.7% respectively, P=0.001). The overall accuracy of direct microscopy and clinical examination for predicting vulvo-vaginal candidiasis was only 77% and 51%, respectively, in the diabetic group, and 83% and 65% in the control group.

CONCLUSIONS

Patients with diabetes mellitus had a high prevalence rate (46%) of vulvo-vaginal candidiasis with relative risk of 2.45. The non- C. albicans species such as C. glabrata and C. tropicalis were the predominant species isolated among them. There seems to be a significant link between hyperglycaemia and vulvo-vaginal candidiasis.