Effect of Diabetes on Rotary Instrumentation of Dentin

Impact of Type 2 Diabetes Mellitus on the Occurrence of Vertical Root Fracture: A Case Control Study

INTRODUCTION

The aim of this case-control study was to examine the relationship between type 2 diabetes mellitus (DM) and the occurrence of VRFs. The crack extension, dentin sclerosis, and chemical characteristics of root dentin in teeth with VRF from patients with/without DM were also compared.

METHODS

One hundred and thirty-two patients diagnosed with VRF in crowned root filled posterior teeth were selected. The study was conducted in 2 parts. In Part-1: The cases were matched with control teeth (1:1) for age (±5 years), sex, tooth type, apical extent of root filling, time period after root filling to a diagnosis of VRF, presence or absence of intracanal post and abutment status. The presence or absence of type 2 DM (HbA1c > 6.5) was recorded. In Part-2: The extracted teeth with VRF from the case control study were used to evaluate the extension of VRF, presence of sclerotic dentin and isthmus using a microscopic analysis; while the levels of pentosidine, collagen cross-linking ratio and mineral-collagen ratio were determined by Fourier-transform infrared spectroscopy. The distribution of DM between cases and controls was analyzed using Pearson Chi-Square test and Odds Ratio estimated. Chemical composition data was analyzed using Mann-Whitney test. The extent of sclerotic dentin was analyzed using Pearson Chi-Square test.

RESULTS

When compared to patients without DM, patients with DM had 2.67 (95% CI: 1.6-4.45) folds higher odds for occurrence of VRF. Pentosidine (P = .014), collagen cross-linking ratio(P = .047), mineral-collagen ratio (P = .009) and sclerotic dentin extent (P = .0009) were significantly higher in patients with DM and VRF.

CONCLUSIONS

Type 2 DM was more often associated with VRFs in root canal treated teeth with crowns. Root dentin from patients with type 2 DM and VRF had higher levels of pentosidine, collagen cross-linking ratio, mineral to collagen ratio and sclerotic dentin.

Effect of Lipopolysaccharide-Induced Apical Periodontitis in Diabetes Mellitus Rats on Periapical Inflammation

OBJECTIVES

 To evaluate periapical inflammation through immunohistochemical analysis of interleukin 6 (IL-6) and tumor necrosis factor α (TNF-a) expression resulting from lipopolysaccharide (LPS)-induced apical periodontitis in diabetes mellitus rats, observed at 14, 28, and 42 days.

MATERIALS AND METHODS

 Diabetes model on rats was induced by streptozotocin (STZ). Fifteen rats were injected with low-dose STZ for 5 days and waited for 5 days until the blood glucose level was stable and measured above 300 mg/dL confirmed by a digital glucometer. LPS was used to induce apical periodontitis. After performing access cavity, pulpal and root canal extirpation was done on the right mandibular first molar's root canal space of rats, under anesthesia. LPS of 1 mg/mL dose was induced in the pulpal and root canal space. Apical periodontitis was expected 14 days afterward and then, the rats were randomly allocated to three groups. The first group was terminated 14 days after induction and used as control. The second group was observed 28 days after induction, and the third group was observed 42 days after induction. IL-6 and TNF-a expression was analyzed by immunohistochemistry on macrophages in the periapical area.

STATISTICAL ANALYSIS

 Data were analyzed using one-way ANOVA and continued with the post hoc Tukey HSD test. Significance was considered if p < 0.05.

RESULTS

 LPS induced apical periodontitis in diabetes mellitus rats at control (14 days), 28 and 42 days observation showed a significant increase in the expression of IL-6 and TNF-a. There were significant differences between the control and observed groups (p < 0.05). The expression of IL-6 in the apical area was not significant at 14 and 28 days (p > 0.05) but increased significantly at 42 days (p < 0.05). The expression of TNF-a in the apical area was significantly increased after 14 days (p < 0.05) and remained stable at 28 and 42 days (p > 0.05).

CONCLUSIONS

 The periapical inflammation of LPS-induced apical periodontitis in diabetes mellitus rats increased macrophages' expression of IL-6 at 42 days and TNF-a at 28 days.

Effects of Diabetes on Elemental Levels and Nanostructure of Root Canal Dentin

INTRODUCTION

This study evaluated the effects of diabetes mellitus (DM) on the nanostructure of root canal dentin using high-resolution transmission electron microscopy (HRTEM) and inductively coupled plasma mass spectrometry (ICP-MS).

METHODS

Twenty extracted human premolars from diabetic and nondiabetic patients (n = 10 in each group) were decoronated and sectioned horizontally into 40 2-mm-thick dentin discs, with each disc designated for a specific test. ICP-MS was used to determine the different elemental levels of copper, lithium, zinc, selenium, strontium, manganese, and magnesium in diabetic and nondiabetic specimens. HRTEM was used to analyze the shape and quantity of the apatite crystals in diabetic and nondiabetic dentin at the nanostructural level. Statistical analysis was performed using Kolmogorov-Smirnov and Student t test (P < .05).

RESULTS

ICP-MS revealed significant differences in trace element concentrations between the diabetic and nondiabetic specimens (P < .05), with lower levels of magnesium, zinc, strontium, lithium, manganese, and selenium (P < .05), and higher levels of copper in diabetic specimens (P < .05). HRTEM revealed that diabetic dentin exhibited a less compact structure with smaller crystallites and significantly more crystals in the 2500 nm2 area (P < .05).

CONCLUSION

Diabetic dentin exhibited smaller crystallites and altered elemental levels more than nondiabetic dentin, which could explain the higher root canal treatment failure rate in diabetic patients.

The effect of diabetes mellitus on the shear bond strength of composite resin to dentin and enamel

Diabetes mellitus might be linked to the deterioration of certain physical properties of dentin and enamel. This study aimed to determine the effect of two types of diabetes on the shear bond strength of enamel and dentin, by using the single bond universal bonding system. Sixty specimens [from 15 teeth; 5 from each group-non-diabetic (ND), Diabetic type I (D1), and Diabetic type II (D2)], were prepared with equal amounts of dentin (n = 5) and enamel (n = 5). Enamel specimens (E20) were etched with 37% phosphoric acid, for 20 s, and dentin specimens (D15) were etched for 15 s. A standard shear bond strength test was performed on all specimens. Their failure modes were also studied under a scanning electron microscope, and the data were analyzed by using ANOVA and Post Hoc Tukey's test (a = 0.050). For the enamel groups, significant differences were only noticed between the ND and D1 (P < 0.050) groups, and between the ND and D2 (P < 0.050) groups. In the dentin groups, there was a significant difference only between the ND and D1 (P < 0.050) groups. The micrographs showed that the ND group had the highest number of specimens with cohesive failure and D1 had the highest number of specimens with adhesive failure. It can be concluded that both types of diabetes reduce the shear bond strength of composite resin on dentin and enamel. However, it seems that the negative effect of diabetes on shear bond strength of dental composite resin is more drastic in individuals with type I diabetes as compared with type II.