Influence of Various Desensitizing Mouthrinses and Simulated Toothbrushing on Surface Roughness and Microhardness of Tetric N-Ceram Bulk-Fill Resin Composite: An In Vitro Study and Scanning Electron Microscope Analysis.

OBJECTIVES: Bulk-filled composite resins are popularly used for posterior restorations due to various advantages. Routine oral hygiene measures like toothbrushing and the use of various mouthrinses can influence the mechanical properties of composite resins. Desensitizing mouthrinses are widely used as well, to manage dentinal hypersensitivity. Studies on the influence of desensitizing mouthrinses on bulk-filled composites are limited. Hence, the objective of the present in vitro study was to evaluate the influence of toothbrushing and various desensitizing mouthrinses on the surface roughness and microhardness of Tetric N-Ceram bulk-fill composite resin. MATERIALS AND METHODS: Fifty Tetric N-Ceram bulk-fill composite resin disks were prepared and were randomly divided into five groups (n = 10). Group 1 (Control): no toothbrushing and no mouthrinse; Group 2: toothbrushing only; Group 3: toothbrushing + HiOra-K mouthrinse; Group 4: toothbrushing + Listerine Sensitive mouthrinse; and Group 5: toothbrushing + Shy-OR mouthrinse. The specimens were brushed with a soft bristle brush using a toothpaste slurry and immersed in respective mouthrinse twice daily for 1 month. The mean surface roughness (average roughness) and microhardness (Vickers Pyramid number) values were determined and the data were tabulated. Data were analyzed using one-way analysis of variance, Post-hoc Tukey test, and Pearson correlation test. A p-value less than 0.05 was considered statistically significant. RESULTS: Specimens treated with HiOra-K mouthrinse exhibited maximum surface roughness (p < 0.05) and specimens treated with Listerine Sensitive exhibited the least microhardness (p < 0.05). A weak negative correlation was found between surface roughness and microhardness for groups 1, 2, and 5, while a weak positive correlation was found for groups 3 and 4. CONCLUSIONS: It is suggested that desensitizing mouthrinses containing alcohol or essential oils can lead to increased surface roughness and reduction in microhardness of bulk-fill composites, which could have an undesirable effect on their clinical performance.

A comparative evaluation of Advanced Platelet-Rich Fibrin (A-PRF) and Platelet-Rich Fibrin (PRF) as a Scaffold in Regenerative Endodontic Treatment of Traumatized Immature Non-vital permanent anterior teeth: A Prospective clinical study.

BACKGROUND: Regenerative endodontic treatment (RET) is a promising treatment alternative for traumatized immature non-vital teeth. Advanced platelet-rich fibrin (A-PRF) contains significantly more growth factors than Platelet-rich fibrin (PRF) and has not been evaluated as a scaffold in RET. The aim of the present study was to evaluate and compare A-PRF and PRF as scaffolds in the RET concerning periapical healing, and root development of traumatized immature non-vital teeth. MATERIAL AND METHODS: In the present study, RET was performed on 30 traumatized immature non-vital maxillary incisors in 28 patients aged between 8-27 years. Minimal mechanical debridement and irrigation with 1.5% sodium hypochlorite and 17% ethylenediaminetetraacetic acid was performed. Canals were disinfected using modified triple antibiotic paste consisting of ciprofloxacin, metronidazole and cefaclor. Based on the type of scaffold, teeth were randomly assigned into A-PRF (n=15) and PRF groups (n=15). Periapical healing, apical response and quantitative root dimensions (length and thickness) were analyzed radiographically after 12 months follow-up. RESULTS: Nineteen patients with 21 teeth (A-PRF n=11, PRF n=10) completed the follow-up and 9 patients were excluded. Clinically, patients in both the groups were asymptomatic. The survival rates for A-PRF and PRF were 78.5% and 77.5%, respectively. No statistically significant differences were detected between A-PRF and PRF regarding periapical healing and type of apical response (p& 0.05). The difference in the pre-operative and follow-up root thickness and root length in both A-PRF and PRF groups were statistically significant (p< 0.05). CONCLUSIONS: Based on short-term results of 13 months, both A-PRF and PRF can be used as scaffold in regenerative endodontic treatment of traumatized immature non-vital teeth. A-PRF could be recommended in such cases since it yielded more root dentin thickness which is crucial for reinforcing immature teeth. Key words:Regenerative endodontic treatment, dental trauma, Non-vital teeth, immature teeth, platelet-rich fibrin, advanced platelet-rich fibrin.

Surface Nanohardness of Normal and Fluorosed Enamel Adjacent to Restorative Materials: An In Vitro Study and Polarized Light Microscopy Analysis.

AIM AND OBJECTIVE: To evaluate nanohardness of normal and fluorosed enamel in teeth restored with Cention N (CN), Equia forte (EF), glass ionomer cement (GIC), and resin composite using the nanoindentation test. MATERIALS AND METHODS: Eighty freshly extracted human premolars were selected. Standardized cavities were prepared on the buccal surface of normal (40) and fluorosed (40) teeth. Based on the type of the restorative material, the teeth were subgrouped into (n = 10): CN, EF, Type VIII GIC, and Tetric N-Ceram (TNC). The teeth were subjected to pH cycle (progressive caries test), which consisted of alternative demineralization (18 hours) and remineralization with artificial saliva (6 hours) for 3 consecutive days. Surface nanohardness was determined using a nanoindenter at distances of 100, 200, and 300 µm from the restoration-tooth margin. A polarized light Microscope was used to correlate the effect of remineralization on the enamel. Data were analyzed by one-way ANOVA with the Scheffe's post hoc and independent t-test. RESULTS: Nanohardness values of the fluorosed/normal enamel adjacent to various materials in descending order were as follows: EF 3.67/2.95 GPa, GIC 3.33/3.15 GPa, CN 3.13/3.23 GPa, and TNC 1.17/1.82 GPa, respectively. Statistically significant differences were found among various materials in both types of the enamel (p < 0.05). CONCLUSION: Based on the nanohardness test, EF can be a better choice for restoration in fluorosed teeth, followed by CN and GIC; GIC was better in normal enamel; however, this was not significant compared to CN and EF. Tetric N-Ceram composite resin had least influence on increasing the nanohardness of the adjacent enamel. CLINICAL SIGNIFICANCE: The surface nanohardness of normal and fluorosed enamel can be influenced by the type of restorative material used. The results of present study deserve clinician's attention while selecting restorative materials especially in dental fluorosis.

Evaluation of the remineralisation potential of bioactive glass, nanohydroxyapatite and casein phosphopeptide-amorphous calcium phosphate fluoride-based toothpastes on enamel erosion lesion -An Ex Vivo study.

BACKGROUND: Erosion, a dynamic process with periods of demineralisation and remineralisation, has become a common problem in modern societies, owing to changes in life style and dietary habits. Although fluorides have been included in toothpastes that claim to prevent demineralisation and aid remineralisation, their ability to remineralise is limited by low concentration of calcium and phosphate ions available in saliva. Hence, a new paste based on casein phosphopeptide-amorphous calcium phosphate fluoride (CPP-ACPF), nanohydroxyapatite and bioactive glass (BAG) were introduced. AIM: To evaluate and compare the effects of BAG, nanohydroxyapatite and CPP-ACPF pastes on surface microhardness of demineralised enamel. MATERIALS AND METHODS: 48 enamel specimens were randomly divided into five groups: Group I positive control - intact specimens and Group II - demineralised specimens. The test groups, Group III, IV and V, comprised CPP-ACPF, nanohydroxyapatite and BAG, respectively. The test specimens were demineralised with 0.1% citric acid followed by remineralisation using either of the three prepared slurries. The specimens were subjected to pH cycling regime for 15 times. The remineralisation potential of the specimens was studied by evaluating the surface microhardness. One specimen from each group was analysed under SEM. Data was tabulated and analysis performed by one way ANOVA and post hoc Scheffe test. RESULTS: Statistically significant difference was found between the negative control and three test groups based on microhardness evaluation. Nanohydroxyapatite had the least remineralising potential as compared to CPP-ACPF and BAG. CONCLUSION: Comparatively, BAG and CCP-ACPF paste showed better remineralising potential.

Comparison of the Antimicrobial Efficacy of Octenidine Dihydrochloride and Chlorhexidine with and Without Passive Ultrasonic Irrigation - An Invitro Study.

INTRODUCTION: Elimination of microorganisms from infected root canals is a complicated task. Numerous measures have been described to reduce the microbial load in the root canal system, including the use of various instrumentation techniques, irrigation regimens and intracanal medicaments. The drawbacks of few commonly used irrigants include toxic and harmful side effects, microbial resistance to antimicrobial agents and staining. Hence there is a need for alternative agents which are nontoxic, effective and safe. AIM: To compare and evaluate antimicrobial effects of 2% Chlorhexidine (CHX) versus 0.1% Octenidine Dihydrochloride (OCT) as root canal irrigant with and without passive ultrasonic irrigation against Enterococcus faecalis (E. faecalis) in vitro and to evaluate the depth of penetration of irrigant solution into the dentinal tubules at the junction of middle and apical third. MATERIALS AND METHODS: Forty eight freshly extracted, single rooted human mandibular premolars were decoronated and root specimen standardized to 14mm. Biofilm of E. faecalis (strain ATCC 29212) was grown for seven days and the specimens were divided into four groups (n=12) based on irrigation protocol : Group I- Conventional Syringe Irrigation (CSI) with 2% CHX, Group II- CSI + 0.1% OCT, Group III-Passive Ultrasonic Irrigation (PUI) + 2% CHX and Group IV- PUI+ 0.1% OCT. Dentin shavings were collected at two depths (200µm and 400µm) and total number of colony forming units were determined. The data were statistically analyzed using ANOVA, Scheffes multiple comparison of means and paired t-test (p<0.05). RESULTS: Group III and IV (PUI) showed significant difference compared to Group I and II (CSI) both at 200µm and 400µm (p=0.000). For Group III and Group IV no significant differences were found at 200µm and 400µm (p=1.000 and 0.363 respectively), however significant difference was found between data at 200µm and 400µm for all the four groups (p=0.000). CONCLUSION: Octenidine (0.1%) was more effective than 2% Chlorhexidine against E. faecalis both at 200µm and 400µm. Passive ultrasonic irrigation proved to enhance the antimicrobial action of the irrigants.

An in vitro evaluation of the accuracy of four electronic apex locators using stainless-steel and nickel-titanium hand files.

OBJECTIVES: The purpose of this in vitro study was to evaluate the accuracy of working length (WL) determination of four electronic apex locators (EALs), namely, Root ZX (RZX), Elements diagnostic unit and apex locator (ELE), SybronEndo Mini Apex locator (MINI) and Propex pixi (PIXI) using Stainless steel (SS) and nickel-titanium (NiTi) hand files. The null hypothesis was that there was no difference between canal length determination by SS and NiTi files of 4 EALs. MATERIALS AND METHODS: Sixty extracted, single rooted human teeth were decoronated and the canal orifice flared. The actual length (AL) was assessed visually, and the teeth were embedded in an alginate model. The electronic length (EL) measurements were recorded with all four EALs using SS and NiTi files at '0.5' reading on display. The differences between the AL and EL were compared. RESULTS: The results obtained with each EAL with SS and NiTi files were compared with AL. A paired sample t test showed that there was a statistical significant difference between EAL readings with SS and NiTi files for RZX and MINI (p < 0.05). The accuracy of RZX, ELE, MINI and PIXI within ± 0.5 mm of AL with SS/NiTi files were 93.3%/70%, 90%/91.7%, 95%/68.3%, and 83.3%/83.3%, respectively. CONCLUSIONS: The results of this study indicate that Root ZX was statistically more accurate with NiTi files compared to SS files, while MINI was statistically more accurate with SS files compared to NiTi files. ELE and PIXI were not affected by the alloy type of the file used to determine WL.