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.

Evaluation of Different Agitation Techniques on Smear Layer Formation and Dentine Erosions- An In Vitro Study.

OBJECTIVE: This study was performed to assess smear layer formation and erosion after final irrigation protocols with metal and non-metal tips in the apical third of root canals. METHODS: Forty mandibular premolars were instrumented with ProTaper Gold files up to F3 and embedded in a closed silicone flask system. The teeth were subsequently cleaved and 4 sequential indentations (1 to 4 mm from the apical foramen) were prepared on the buccal root canal walls to standardize sites for environmental scanning electron microscopy (ESEM) imaging. The samples were cleaned in an ultrasonic bath and observed under ESEM (controls), reassembled and divided into four groups (n=10 each) and subjected to different final irrigation protocols; XPF Group (XP-endo Finisher) and PUI Group (passive ultrasonic irrigation) with metal tips; EA Group (EndoActivator) and MDA Group (Manual dynamic agitation) with non-metal tips. The smear layer formation and dentine erosion were evaluated using ESEM. The data were analyzed with Kruskal-Wallis test with Bonferroni correction. RESULTS: In comparison to the control groups, XPF group had significantly increased smear layer formation at 1 and 2 mm (P<0.05). PUI group had significantly higher smear layer (P<0.05) formation at 3mm while EA and MDA groups did not present with significantly higher smear layer at all levels. Erosion was significantly higher (P<0.05) in MDA, XPF and PUI groups at all levels when compared to controls while EA group presented with significantly more erosion only at 2 and 3 mm. CONCLUSION: Final irrigation protocol using EA and MDA with non-metal tips did not result in significant smear layer formation. Dentine erosion was observed after all experimental irrigation protocols. (EEJ-2021-12-194).

Clinical Outcome of Nonsurgical Root Canal Treatment Using a Matched Single-Cone Obturation Technique with a Calcium Hydroxide-based Sealer: A Retrospective Analysis.

INTRODUCTION: The aim of this retrospective study was to estimate the outcome of nonsurgical root canal treatment using matched single-cones with a calcium hydroxide-based sealer and to identify the various prognostic factors influencing the outcome. METHODS: This was a retrospective study that enrolled 272 patients who underwent routine endodontic therapy and were obturated with matched single-cones and Sealapex as sealer. This study involved 223 patients with 261 teeth meeting the selection criteria and recalled between 24 and 84 months. The outcome was categorized as success (healed/healing clinically and radiographically) or failure (not healed clinically and/or radiographically). Two calibrated examiners assessed the treatment outcomes. A binomial logistic regression model was performed to identify the effect of various prognostic factors. The χ2 test was used to find the association between sealer extrusion and the initial periapical index scores. RESULTS: The overall success rate was found to be 89.7% for a mean recall period of 39.18 (±11.05) months. An increase in age was associated with increased odds of success, whereas the success rates were reduced by an increase in the number of roots and negative pulp sensibility status. Initial periapical index scores, presence of preoperative sinus tract, number of visits, and sealer extrusion did not affect the outcome significantly (P > .05). CONCLUSION: Within the limitations of this study, it was found that teeth obturated with matched single-cone and Sealapex achieved substantial success rates. Sealer extrusion did not have any significant effect on the treatment outcome.

In Vivo Strain Alterations in Mandibular Molars after Root Canal Treatment Procedures.

INTRODUCTION: The aim of this investigation was to determine the coronal strain variations in mandibular molars under an in vivo bite load after root canal treatment procedures. METHODS: The coronal strain in carious mandibular first molars with symptomatic irreversible pulpitis (experimental group) was compared with that of intact contralateral teeth (control group) in patients 20-40 years old. Experiments were conducted in 2 stages. In stage 1, the maximum bite force on the first molar region was determined on the experimental and control teeth using a customized load cell. In stage 2, strain gauges were bonded to the buccal aspect of teeth, and the strain was recorded after the application of a bite load on the intact (control) teeth; and the experimental teeth before and after endodontic access cavity preparation, cleaning/shaping procedures, root filling, and composite core restoration. RESULTS: The mean maximum bite force on the experimental teeth (91 ± 48 N) and the contralateral control teeth (91 ± 49 N) was not significantly different (P = .989). The preoperative strain (microstrain) in the experimental teeth was significantly higher (125 ± 36, P = .001) than in the contralateral intact teeth (46 ± 17). Access cavity preparation significantly increased the strain (327 ± 98, P = .019) on the experimental teeth compared with the preoperative strain. Cleaning/shaping (355 ± 113) and root filling (346 ± 89) did not significantly increase (P = 1.00) the strain compared with the strain determined after endodontic cavity preparation. Composite core restoration in the experimental teeth (106 ± 41) resulted in a significant reduction in the strain compared with the values recorded after an endodontic access cavity (P = .002) and was similar to the preoperative strain values (P = 1.00) but was significantly higher than the strain values in contralateral intact teeth (P = .001). CONCLUSIONS: The coronal strain on the buccal surface of mandibular first molars significantly increased with access cavity preparation, which did not increase further after cleaning/shaping or root filling. A significant reduction in the strain induced by root canal treatment steps was evident after composite core restoration.

Coronal Bacterial Penetration after 7 days in class II endodontic access cavities restored with two temporary restorations: A Randomised Clinical Trial.

The aim of this in vivo randomised clinical trial was to assess coronal bacterial penetration after placement of Cavit G and IRM temporary restorations in Class II endodontic access cavities. After completion of endodontic treatment, placement of an orifice seal and disinfection of the operating field, sterile cotton pellets were placed in the pulp chamber and the cavities were restored with Cavit G or IRM. After 7 days, coronal and proximal restoration thickness was measured by digital radiographs. Cotton pellet was evaluated by culture methods and polymerase chain reaction assay and bacterial species identified. Bacterial growth was observed in 5 of the 27 (18%) Cavit G samples and in 11 of the 27 (40%) IRM samples which was not significant. Coronal restoration thickness of 4-5 mm and proximal restoration thickness of more than 2.15 mm for Cavit G and 2.35 mm for IRM are recommended to prevent bacterial penetration over 7 days. Adequate restoration thickness is critical to prevent bacterial penetration.

Esterase like activity of Enterococcus faecalis and Lactobacillus casei on microhardness and weight loss of resin luting cements.

INTRODUCTION: Gap-free/continuous cement margins have been considered important for the longevity of indirect dental restorations. Bacterial species have demonstrated esterase-like activity that can cause biodegradation of resin composites. AIM: The aim of this study was to evaluate the effect of the esterase-like activity of E. faecalis and L. casei on three resin luting cements. SETTINGS AND DESIGN: In-vitro study materials and three resin luting cements tested were: Variolink N, Rely X U200 and Panavia F2.0. E. faecalis and L. casei suspensions and supernatants were assessed for enzymatic activity by bacterial esterase activity assay. Circular samples of resin luting cements were exposed to suspensions of E. faecalis and L. casei for 7 and 28 days followed by testing for solubility, microhardness and bishydroxy propoxy phenyl propane (BisHPPP) release. RESULTS: E. faecalis and L. casei both demonstrated esterase-like activity. Bacterial suspensions had significantly increased enzymatic activity than supernatant solutions (P < 0.05). There was no significant reduction in microhardness or increased weight loss in all three cements after incubation in E. faecalis and L. casei for 7 and 28 days. BisHPPP release signifying resin degradation was seen after 7 and 28 days of incubation in E. faecalis and L. casei. CONCLUSION: Within the limitations of this in vitro study, E. faecalis and L. casei demonstrated esterase-like activity. BisHPPP release was evident in all three cements after 7 and 28 days. However, the bacterial strains did not significantly reduce the microhardness or cause weight loss of the tested resin luting cements (Variolink N, Panavia F2.0 and Rely X U200) after 7 and 28 days of incubation.

Root Canal Preparation Does Not Induce Dentinal Microcracks In Vivo.

INTRODUCTION: This in vivo study aimed to evaluate the development of dentinal microcracks after root canal preparation of contralateral premolars with rotary or hand instruments using micro-computed tomographic technology. METHODS: Sixty contralateral intact maxillary and mandibular premolars in which extraction was indicated for orthodontic purposes were selected and distributed into positive (n = 6, teeth with induced root microcracks) and negative (n = 6, intact teeth) control groups as well as 2 experimental groups (n = 24) according to the instrumentation protocol: ProTaper rotary (PTR) or ProTaper hand (PTH) systems (Dentsply Maillefer, Ballaigues, Switzerland). After root canal preparation, teeth were extracted using an atraumatic technique and scanned at a resolution of 17.18 µm. A total of 43,361 cross-sectional images of the roots were screened for the presence of dentinal microcracks. The results were expressed as the percentage and number of root section images with microcracks for each group. RESULTS: All roots in the positive control group showed microcracks at the apical third, whereas no cracks were observed in the specimens of the negative control group. In the PTR group, 17,114 cross-sectional images were analyzed, and no microcrack was observed. In the PTH group, dentinal microcracks were observed in 116 of 17,408 cross-sectional slices (0.66%) of only 1 specimen. These incomplete microcracks extended from the external root surface into the inner root dentin at the area of reduced dentin thickness. CONCLUSIONS: Root canal instrumentation with PTR and PTH instruments of contralateral maxillary and mandibular premolars did not result in the formation of dentinal microcracks in vivo.

Effect of two desensitizing agents on dentin hypersensitivity: A randomized split-mouth clinical trial.

BACKGROUND: Clinical research is important to evaluate the effect of desensitizing agents. AIMS: This randomized clinical trial evaluated the immediate and 1 week desensitizing effect of two desensitizing agents Uno Topical Gel and Profluorid. MATERIALS AND METHODS: Thirtyfive patients with teeth presenting with dentin hypersensitivity were included in this clinical trial. Each quadrant in a patient was randomly assigned to one of two groups: Uno Topical Gel or Profluorid Varnish. A VAS score was used to assess tooth sensitivity at baseline, immediately after application of desensitizer and after 1 week. Additionally, 30 dentin discs were prepared, divided into Group 1(Control Group), Group 2 (Profluorid Varnish) and Group 3 (Uno Topical Gel) and examined using scanning electron microscopy (SEM) after 1hour and 24 hours to evaluate tubule occlusion. STATISTICAL ANALYSIS: Clinical data were analysed using Friedman's test and Mann - Whitney U test. SEM data was analysed using Student's 2-sample t-test. RESULTS: Uno group was significantly better to evaporative stimuli immediately (P=0.01) after application. After 1 week, Uno group was significantly better to tactile (P=0.000) and evaporative (P=0.000) stimuli than Profluorid. SEM images showed that 1 hour after application, Uno and Profluorid demonstrated more than 90% and 80% dentin tubule occlusion respectively. At 24 hours, Uno and Profluorid demonstrated more than 50% and 60% dentin tubule occlusion respectively. CONCLUSIONS: Uno Topical Gel was significantly better than Profluorid in reducing pain of dentin hypersensitivity due to tactile and evaporative stimuli after 1 week.

Remineralization ability of sodium fluoride on the microhardness of enamel, dentin, and dentinoenamel junction: An in vitro study.

AIM: Dental tissues such as enamel, dentinoenamel junction (DEJ), dentin, and root dentin can react differently to demineralization and remineralization. The aim of this study was to evaluate the remineralization ability of sodium fluoride on the microhardness of enamel, dentin, and dentinoenamel junction. MATERIALS AND METHODS: Ten extracted third molar teeth were sectioned mesiodistally to form control and test groups. For the test group, initial demineralization was done with acetic acid for 24 h followed by remineralization for 28 days by application of sodium fluoride (226 ppm) for 2 min twice a day. Vickers microhardness test was done to control and test groups at different sites after initial demineralization and on the 3rd, 5th, 7th, 14th, and 28th day of remineralization. STATISTICAL ANALYSIS USED: Data were analyzed with one-way analysis of variance and post hoc test with a significance level of P < 0.001 with SPSS (21) software. RESULTS: Microhardness values in the demineralization group were significantly lower than controls (P < 0.001). Evaluation of remineralization samples showed that microhardness similar to control values were achieved at the 3rd day in root predentin and on the 5th day in coronal dentin and coronal predentin. On the 7th day, remineralization coronal predentin was significantly higher than the control (P < 0.001). On the 14th day, DEJ axial zone and root dentin were similar to control and coronal dentin was significantly higher than the control (P < 0.001). Enamel was similar to control on the 28th day. Microhardness of DEJ-cusp tip and DEJ-center of the fissure was significantly lower than control even at the 28th day (P < 0.001). CONCLUSION: Long-term repeated application of sodium fluoride (226 ppm) can improve the microhardness of demineralized dental tissues on enamel, dentin, and DEJ-axial zone, except in the DEJ-cusp tip and DEJ-center of fissure.

Preexisting Dentinal Microcracks in Nonendodontically Treated Teeth: An Ex Vivo Micro-computed Tomographic Analysis.

INTRODUCTION: This study evaluated the prevalence, location, and pattern of preexisting dentinal microcracks in roots of extracted teeth without endodontic treatment in patients from 2 age groups using micro-computed tomographic imaging. METHODS: Six hundred thirty-three nonendodontically treated teeth extracted using an atraumatic procedure because of reasons unrelated to this study were collected and divided based on the patient age. Teeth were scanned with micro-computed tomographic imaging (resolution of 26.7 µm) to examine the presence of preexisting dentinal microcracks in roots. The characteristic features of preexisting dentinal microcracks determined were location, extent, length, and coronoapical distribution. Chi-square bivariate analysis was performed to assess the association between various parameters. RESULTS: Forty-five of 633 nonendodontically treated teeth exhibited preexisting microcracks in roots with a prevalence of 7.1%. The prevalence of preexisting microcracks was found to be 8.3% in older patients (40-70 years) compared with 3.7% in younger patients (20-39 years) (P < .050). A significant association was found between the preexisting microcracks in mandibular teeth (10.3%) when compared with maxillary teeth (2.9%) (P < .001). All preexisting microcracks were located mesiodistally; 66% occurred in the cervical and middle thirds of root. Only 33% of the preexisting microcracks were complete in nature, showing canal involvement. Complete dentinal microcracks exhibited a mean length of 6.9 mm, whereas incomplete cracks had a mean length of 3.75 mm (P < .001). CONCLUSIONS: Preexisting dentinal microcracks in roots of nonendodontically treated teeth occurred more often in older patients (40-70 years) in the mesiodistal direction. They were predominantly found in the cervical and middle thirds of root and were more likely to be incomplete in nature.

Diagnosis of Vertical Root Fractures in Restored Endodontically Treated Teeth: A Time-dependent Retrospective Cohort Study.

INTRODUCTION: The purpose of this study was to examine different patient- and treatment-related factors associated with the time of presentation of vertical root fractures (VRFs) in endodontically treated teeth restored with crowns. METHODS: One hundred ninety-seven root-filled, crowned teeth with no post and suspected of VRFs were included in the study. Patient details with relevance to endodontic treatment and clinical signs/symptoms were documented, and radiographs were taken. A diagnosis of a VRF was confirmed after surgical flap elevation. Frequency distributions were determined, and statistical analyses were performed using Pearson chi-square analysis, Fisher exact test, cross tabulation, Pearson correlation, and multiple logistic regression. RESULTS: Mandibular molars (34%) and maxillary premolars (22.8%) were the most frequently affected teeth. The postoperative time to the diagnosis of a VRF was 4.35 (±1.96) years. Female patients, posterior teeth, overfilled canals, and patients older than 40 years were associated with the presentation of VRFs within 5 years of the postoperative period. Clinical findings most frequently observed were pain on percussion (60%), pain on palpation (62%), presence of a deep narrow pocket (81%), and sinus tract/swelling (67%). "Halo"-type radiolucency (48.7%) was the most common radiographic feature related to VRFs. CONCLUSIONS: Pain on palpation/percussion, deep narrow pocket, sinus tract, and halo-type radiolucency are characteristic features of VRFs. Posterior teeth, overfilled canals, female patients, and older patients (>40 years) presenting with the previously described clinical features in endodontically treated teeth restored with crowns are more likely to present with VRFs within 5 years postoperatively.