Comparative evaluation of treatment outcome of partial pulpotomy using different agents in permanent teeth-a randomized controlled trial.

AIM: To compare and evaluate the clinical and radiographic performance, post-operative pain, and anti-inflammatory intake after partial pulpotomy (PP) with calcium hydroxide (CH), mineral trioxide aggregate (MTA), Biodentine (BD), and Emdogain (EMD) as pulp capping agents in mature permanent molars with definitive diagnosis of reversible pulpitis. MATERIALS AND METHODS: As part of this prospective, randomized clinical trial with four parallel arms (CTRI Registration No.: CTRI/2020/11/029329 dated 24/11/2020), hundred and ten permanent molars with a clinical diagnosis of reversible pulpitis and normal apical tissues, from patients between the ages of 15 and 45 years, were recruited and randomly assigned to four groups-CH, MTA, BD, and EMD. Operative procedure was performed under local anesthesia and dental dam isolation. After carious pulpal exposure, 2 mm of superficially inflamed coronal pulp tissue was amputated and either of the four pulp capping materials was placed. The outcome assessment was carried out at 1, 3, 6, and 12 month(s) and was categorized as success (asymptomatic patients with PAI score = 1) or failure (symptomatic patients or PAI score > 1). RESULTS: There was a significant difference in post-operative pain and anti-inflammatory medication intake after partial pulpotomy with Emdogain vis-à-vis other three capping agents. No difference in both clinical and radiographic performances was observed among the four capping agents. CONCLUSION: Partial pulpotomy when performed following evidence-based guidelines results in high success rates regardless of capping agent employed. EMD can be considered a valid and suitable pulp capping agent in PP. CLINICAL RELEVANCE: Meticulous examination and removal of superficially inflamed pulp under magnification and complete asepsis lead to successful pulpal healing regardless of capping agent employed.

Spectrophotometric evaluation of color stability of novel composites following exposure to antioxidant beverages: An in vitro study.

Background: Color matching and stability are the essential considerations in restorative dentistry, as they contribute to the longevity and esthetic appeal of the restorations. Composites with nanoparticles and more filler content are anticipated to be more color-stable. Aim: The aim of the study was to assess and contrast the color stability of esthetic restoration materials following exposure to various antioxidant beverages. Materials and Methods: A Class V cavity was prepared on the buccal surface of 40 maxillary premolars. The specimens were divided into two groups: microhybrid (MH) and nanohybrid (NH) composite. The baseline color of each tooth sample was measured and then, the samples were categorized into four subgroups based on the immersion solution (pomegranate juice, beetroot juice, black plum juice, and distilled water) and evaluated on day 1, day 7, day 14, and day 21 using a spectrophotometer-based on CIE L*a*b* color scale. For spectrophotometer analysis, CIE XYZ data were obtained and converted to CIELAB. The samples mean difference in ΔE values before and after being immersed in various beverages. Statistical Analysis: The data were statistically analyzed using an independent t-test and one-way analysis of variance. Results: MH and NH composite materials showed color change after being exposed to the test beverages. Conclusion: MH composite causes more color change than NH composite at all-time intervals. Black plum showed the greatest discoloration in both composites.

Comparative evaluation of dentinal tubule penetration and push-out bond strength of new injectable hydraulic calcium disilicate based root canal sealer: A single blinded in vitro study.

Objective: To evaluate and compare dentinal tubule penetration and push-out bond strength of BIO-C ION+, AH Plus and NanoSeal-S using Confocal Laser Scanning Microscopy (CLSM) and Universal Testing Machine (UTM). Materials & method: Sixty human mandibular premolars were prepared using ProTaper Gold till F3. Samples were then divided into 3 groups: Group I (n = 20) BIO-C ION + sealer, Group II (n = 20) AH Plus and Group III (n = 20) NanoSeal-S sealer. Groups were then sub-divided into two sub groups: In Subgroup A (n = 10) samples were obturated using single-cone with 0.1 % Rhodamine B dye and in Subgroup B (n = 10) samples were obturated using single cone. The samples were then transversely sectioned into coronal, middle and apical segments, samples in subgroup A & B were then submitted to CLSM analysis and UTM respectively. Results: The Bond Strength data showed following means (MPa): Group I Subgroup B: (BIO-C ION+) coronal (1.64), middle (1.25), apical (0.93); Group II Subgroup B: (AH Plus) coronal (2.20), middle (1.85) apical (1.38) and Group III Subgroup B: (NanoSeal-S) coronal (1.26), middle (0.94), apical (0.58). The dentinal tubule penetration data showed following means: (µm) Group I Subgroup A (BIO-C ION+) coronal (1184.69), middle (997.03), apical (637.26); Group II Subgroup-A AH Plus (864.14) and NanoSeal-S (495.64). Statistical analysis (two-way ANOVA, Tukey's Post Hoc Test) showed significant difference among sealers (p < 0.001) and root canal thirds (p < 0.001). Conclusion: The results of the study concluded that BIO-C ION + sealer showed maximum dentinal tubule penetration and AH Plus demonstrated maximum push-out bond strength.

Outcome of novel pulp capping modalities after full pulpotomy in teeth diagnosed with irreversible pulpitis: A prospective randomized clinical trial.

Objective: The study aimed to compare and evaluate the effect of biodentine (BD) alone, BD along with Lyophilised freeze dried platelet rich concentrate (LPC + BD), and BD along with low-level laser therapy (BD + LLLT) after pulpotomy in mature permanent molars with irreversible pulpitis. Materials and Methods: The study was designed as a randomized, pragmatic, parallel, double-blinded clinical trial registered under the Clinical Trial Registry-India (CTRI/2020/02/023245). 120 permanent molars fulfilling the inclusion and exclusion criteria with symptoms of irreversible pulpitis were randomized after performing pulpotomy into three pulp capping groups: Group 1, BD; Group 2, lyophilized freeze-dried platelet-rich concentrate + BD (LPC + BD); and Group 3, Low level laser therapy + BD Group 3, LLLT + BD. The intergroup comparison was done using one-way analysis of variance followed by the Bonferroni test. The level of significance and confidence interval were 5% and 95%, respectively. Interobserver reliability was measured using Cohen's kappa analysis. Results: At 1 week, there was a significant difference (P < 0.005) observed in the mean postoperative pain levels between the three groups with Group 1 (BD) exhibiting the highest postoperative pain followed by Group 2 (LPC + BD) and least pain was exhibited by Group 3 (LLLT + BD). A similar pattern was observed regarding the analgesic intake with maximum frequency in Group 1 (BD) and least with Group 3 (LLLT + BD). No significant difference in success rates was reported among the groups. Conclusion: Pulpotomy as a treatment option for mandibular molars with irreversible pulpitis has an acceptable clinical success rate; however, long-term overall success rate remains questionable. The outcomes of incorporating adjunctive modalities with BD are remarkable and show tremendous potential for continued development and research.

Stress distribution in endodontically treated external cervical resorption lesions restored with MTA and biodentine - A finite element analysis.

Introduction: Root resorption poses a significant challenge in dental practice, with external cervical resorption (ECR) being a common manifestation. ECR is often asymptomatic until advanced stages, complicating its diagnosis and management. Various factors contribute to its etiology, ranging from trauma to orthodontic treatment. The classification system proposed by Patel et al. (2018) offers a comprehensive framework for characterizing ECR lesions based on location and extent. Treatment strategies for ECR involve a combination of endodontic intervention and restorative techniques, with bioactive materials like mineral trioxide aggregate (MTA) and Biodentine emerging as promising options. However, the biomechanical behavior of teeth restored with these materials in the context of ECR remains underexplored. Materials and methods: This study utilized finite element analysis (FEA) to assess stress distribution in teeth with simulated ECR lesions of varying sizes and locations, restored with MTA or Biodentine. Three-dimensional models of maxillary central incisors were generated based on CBCT scans, incorporating periodontal ligament and surrounding bone structures. Eight experimental models representing different ECR configurations were created and subjected to FEA using Optistruct software based on dimensional classification given by Patel et al., in 2018, A70 M & A70B: 1Ap, A130 M & A130B: 1Bp, B70 M & B70B: 2Ap, B130 M & B130B: 2Bp. All the models were tested for stress distribution by restoring the lesions with either M: MTA or B: Biodentine. Oblique load of 100 N was applied at 45°angle to the long axis 2 mm lingual to incisal edge. vonMises Stress distribution in enamel, dentine, restoration and at all the interfaces were observed. Results: The analysis revealed that both MTA and Biodentine restorations exhibited uniform stress distribution around ECR lesions, with no significant differences based on lesion location or size. Maximum stress concentrations were observed around the restorations, particularly in subcrestal lesions. However, overall stress levels were comparable between MTA and Biodentine restorations, indicating similar biomechanical performance. Conclusion: Finite element analysis provides valuable insights into the biomechanical behavior of teeth with ECR lesions restored with MTA and Biodentine. Both materials exhibit similar stress distribution patterns and offer adequate reinforcement against mechanical forces. Clinicians can confidently utilize MTA or Biodentine in the management of ECR, considering their favorable biomechanical properties and clinical outcomes. Further research is necessary to validate these findings and optimize treatment protocols for ECR.

Comparative evaluation of remineralization potential of novel bioactive agents on eroded enamel lesions: A single-blinded in vitro study.

Objective: The escalating prevalence of noncarious tooth wear stands as a critical concern in the backdrop of evolving lifestyles and dietary patterns. Dental erosion, a progressive condition induced by both endogenous and exogenous acidic influences, directly impacts enamel integrity, resulting in surface loss. The contemporary surge in carbonated beverage consumption further exacerbates this erosive milieu, underscoring the urgency for dental practitioners to adopt meticulous treatment strategies. Existing literature underscores a noteworthy 94% reduction in tooth erosion risk for individuals abstaining from sweetened soft beverages, emphasizing the imperative for a well-devised remineralization protocol to counter demineralized surfaces. Methodology: Seventy-three enamel specimens were taken. Forty samples were subjected to pre-operative hardness testing, and five samples were subjected to baseline EDX evaluation followed by grouping of samples (Group 1 = control Group; Group 2 = casein phosphopeptide-amorphous calcium phosphate fluoride [CPP-ACPF] Group; Group 3 = Biomin F Group; and Group 4 = self-assembling peptide [SAP] P-114 Group). A demineralization-remineralization cycle was carried out for 5 days followed by testing through Vickers Microhardness Tester, EDX Evaluation, and Scanning Electron Microscopy (SEM) Imaging. Statistical analysis was performed using one-way analysis of variance followed by intergroup analysis using Tukey's post hoc test with SPSS software 25.0 version. Results: The mean percentage change in microhardness values was 30.05% in Group 1, 24.21% in Group 2, 18.85% in Group 3, and 12.08% in Group 4. The mean Ca/P ratio of samples tested through EDAX was 2.20 at baseline, 1.40 in Group 1 (Control Group), 1.62 in Group 2 (CPP-ACPF), 1.82 in Group 3 (Biomin F), and 2.01 in Group 4 (SAP-P114). Postintervention values were statistically significant from baseline values in both parameters. Conclusion: Curodont Protect exhibits superior efficacy, offering valuable insights for future in vivo studies and clinical applications. The multifaceted evaluation, encompassing microhardness testing, SEM analysis, and EDXS assessment, contributes to a nuanced interpretation of the agents' impact, paving the way for informed decisions in clinical practice and future research endeavors.

The effect of bioactive glass-based, bioceramic based and epoxy amine resin based root canal sealers on post-obturation pain: A double blinded randomized controlled trial.

Aim: The aim of this study was to compare the effect of two calcium silicate-based and an epoxy resin-based root canal sealers on postoperative pain and analgesic intake following single-visit root canal treatment. Materials and Method: Ninety patients with at least one first or second molar tooth diagnosed as symptomatic irreversible pulpitis and symptomatic apical periodontitis were selected and allocated into three groups (n=30) according to the sealer used. Root canals were prepared using Protaper Gold instruments (Dentsply Sirona) in a crown down technique and irrigated with 2.5% NaOCl (Calyx, India) and saline solution. Root canal filling was then accomplished with a single cone obturation technique and treated in a single visit by the same endodontist. Patients were told to use a Visual Analog Scale (VAS) to rate their postoperative pain severity as none, minimal, moderate, or severe after 6 h, 24 h, 48 h, 5 days and 7 days following obturation using the appropriate sealers. The need for analgesic intake was also recorded. The data were statistically analyzed. Results: Results showed a significant difference among the studied groups. Bio-C Sealer Ion+ reported the least pain score followed by Nishika Canal Sealer BG and AH plus sealer at all the time intervals recorded. The intergroup analysis, revealed was a significant difference in postoperative pain at 6 h (p=0.000) and 24 h (p = 0.028), but not at 48 h, 5 day or 7 days (P > 0.05). VAS ratings for all the three groups decreased over time. Also, there were significant differences between the means of analgesic intake among 3 groups (p=0.022). Analgesic intake in group BIO-C Sealer Ion+ is significantly lesser than AH Plus and Nishika Canal Sealer BG group. Conclusion: Calcium silicate-based sealer (Nishika Canal Sealer BG and Bio-C Sealer Ion+) resulted in significantly lower levels of pain as compared to epoxy resin-based sealer (AH Plus) at 6h and 24-h interval, there was no significant difference in postoperative pain occurrence at 48-h, 5 day and 7-day period. The analgesic intake in Bio-C Sealer Ion+ group is significantly lesser than Nishika Canal Sealer BG and AH Plus group.

Evaluating the Concentration of MMP-9 and TNF- α in Pulpal Blood at Various Stages of Pulpal Inflammation in Diabetics: A Cross Sectional Study.

OBJECTIVE: To investigate the concentration of Matrix metalloproteinases-9 (MMP-9) and Tumor necroses fac- tor-alpha (TNF- α) in pulpal blood at various stages of pulpal inflammation in diabetics and to establish the relationship between these two biomarkers. METHODS: 77 patients, each having a tooth with pulpal exposure due to caries presenting with distinct stages of pulpitis were grouped into 2 main study groups as based on the HbA1c Levels-Group 1: Non-Diabetics (Control Group) (HbA1c < 5.6%) and Group 2: Type 2 Diabetics (Experimental Group) (HbA1c>6.5%; Random Plasma Glucose > 200) and diabetes mellitus with less than 10-year history. Depending on the radiological and clinical diagnosis, these two groups were again sub-divided into 2 subgroups: Sub-group A: Tooth with Symptomatic Irreversible Pulpitis. Sub Group B: Tooth with Reversible Pulpitis. Thus, for comparison purposes, a total of 4 sub-divisions were formed: Sub-group 1A- Non-Diabetic, Symtomatic Irreversible Pulpitis, Sub- group 1B: Non-Diabetic, Reversible Pulpitis, Sub-group 2A: Diabetic, Symptomatic Irreversible Pulpitis, Sub- group 2B: Diabetic, Reversible Pulpitis. Blood sample was collected from pulp chamber after partial pulpo- tomy was done. The total levels of MMP-9 and TNF-α were assessed by enzyme linked immunosorbent assays (ELISA). Inter-group comparison in levels of MMP-9 and TNF- α were conducted using the Kruskal Wallis test and pairwise comparison was done Mann-Whitney U test. RESULTS: The inter-group comparison in levels of MMP-9 and TNF- α were conducted using the Kruskal Wallis test and pairwise comparison was done using Mann-Whitney U test. Pearson correlations were conducted in order to investigate correlations between the paired TNF-α and MMP-9 values and also their correlation with the blood sugar levels within the pulp diagnosis groups. MMP-9 and TNF-α levels were significantly higher (p<0.005) in irreversible pulpits than reversible pulpits and also in Type-2 diabetics than non-diabetics. High- est level of MMP-9 and TNF-α was found in Group 2A (Diabetic, symptomaticirreversible pulpitis) and lowest in Group 1B (Non-Diabetic, reversible pulpitis). There exists a very high significant positive correlation between MMP-9 and TNF-α (p<0.005). CONCLUSION: These findings show that the inflammatory mediators MMP-9 and TNF-α are significantly in- creased in pulpal blood samples of diabetic patients. Also, in diabetic patients diagnosed with reversible pul- pitis, higher levels of inflammatory pulpal biomarkers were reported that could compromise the success of Vital Pulp Therapy (VPT) and may necessitate endodontic intervention. MMP-9 and TNF- α were reported to have a positive correlation. (EEJ-2023-01-04).

Comparative evaluation of microleakage and hardness of newer posterior restorative materials.

Background: The physical properties of restorative materials are critical when restoring posterior teeth. Restorative materials are continuously evolving in the quest for creating long lasting restorations. Aim and objective: To compare and evaluate microleakage and hardness of three different posterior restorative materials: Cention N, Zirconomer Improved and Solare Sculpt. Materials and methods: For micro leakage evaluation, 40 extracted human third molars were randomly divided into three experimental groups of 10 teeth each and two control group of 5 teeth each. Standardized box shaped class II cavity preparation was done in Group I, II, III and V. In Group V, cavity was prepared but left unrestored. No cavities were prepared in Group IV. Cavities in Group I, II, and III were restored with Cention N, Zirconomer Improved, Solare Sculpt respectively. Teeth were thermocycled together for 500 cycles. All the samples were placed in 2% methylene blue for 24 h. Microleakage evaluation was done using stereomicroscope. For hardness evaluation ten standardized discs of each material were prepared and evaluated using vicker's hardness test. Results: All the groups showed some amount of microleakage. The mean micro-leakage score was significantly more among Group II compared to Group I. There was no significant difference in mean micro-leakage score between Groups I and III. The mean hardness value was significantly more among Groups I and II compared to Group III. Conclusion: No material was able to completely eliminate microleakage. Cention N showed high hardness among the materials tested.

Evaluation of Bacterial Reduction at Various Stages of Endodontic Retreatment After Use of Different Disinfection Regimens: An In Vivo Study.

OBJECTIVE: The present study was conducted to evaluate the presence of aerobic bacteria, anaerobic bacteria, E. faecalis, F. nucleatum, Propionibacteria sp., Actinomyces sp., and their reduction at various stages of endodontic retreatment with the use of conventional protocol (5.25 % Sodium Hypochlorite (NaOCl) as the irrigant along with Calcium Hydroxide (Ca (OH)2) as intracanal medicament and advocated protocol (SmearOFF as the irrigant along with 2% Chlorhexidine (CHX) gel as intracanal medicament). METHODS: Twenty eight patients fulfilling the eligibility criteria were selected for root canal retreatment and randomly allocated into two groups. Group 1: Final irrigant as SmearOFF+Chlorhexidine 2% gelas intracanal medicament (n=14). Group 2: Final irrigant as 5.25% NaOCl+Ca(OH)2 as intracanal medicament (n=14). With aseptic environment, access opening was performed followed by Gutta Percha (GP) removal and sample S1 was collected for bacterial analysis. The biomechanical preparation was done by using Reciproc system with additional finishing with XP-Endo Finisher R. Sample S2 was then collected for bacterial analysis after the final irrigation protocol in the respective groups. Intracanal medicaments were placed for one week and sample S3 was collected. All the samples were subjected to qualitative analysis using PCR and quantification was done by Colony Forming Unit (CFU) analysis. RESULTS: Aerobic [28/28], Anaerobic [28/28], Propionibacterium sp. [20/28] and F. nucleatum [24/28] were the most frequently isolated in S1 sample followed by Actinomyces sp. [16/28] and E. faecalis sp. [19/28]. Chemico-mechanical preparation followed by irrigation (S2 sample) resulted in significant reduction of all types of bacteria in both groups. Group-1 (SmearOFF as the final irrigant) had significantly superior efficacy against aerobic bacteria, E. faecalis and F. nucleatum (P<0.05) as compared to Group-2 (NaOCl). After medicament placement, significant differences between the groups were noted only for the E. Faecalis group. For the S3 samples, the mean bacterial reduction was significant in Aerobic and F. nucleatum in S3 samples for Group 1 and Group 2. CONCLUSION: Chemico-mechanical preparation followed by irrigation resulted in significant reduction in bacterial load irrespective of the final irrigant. SmearOFF was significantly better than NaOCl in minimizing bacterial load of E. faecalis and F. nucleatum. 2% Chlorhexidine gel has superior antimicrobial efficacy against E. faecalis and may be recommended in secondary endodontic treatment.

Effect of dental acid etchant-mediated photodynamic therapy on bacterial reduction and microshear bond strength of composite to dentin - An in vitro study.

OBJECTIVE: The objective of this study was to assess the effect of dental acid etchant (DAE)-mediated photodynamic therapy on bacterial reduction and microshear bond strength of composite to dentin. MATERIALS AND METHODS: Eighty permanent third molars after sample preparation were exposed to a cariogenic challenge with Streptococcus mutans. After incubation, specimens were randomly divided into four groups (n = 20): Group I - DAE, Group II - low-level laser (LLL), Group III - diode laser + methylene blue (MB + L), and Group IV - diode laser + DAE (DAE + L). Half of the specimens from each group were selected for bacterial reduction assessment and the other half for microshear bond strength. All the samples for assessment of bacterial reduction (before and after intervention) were seeded onto the surface of mitis-salivarius-bacitracin medium. After incubation, the viable bacterial count was determined in colony-forming unit/mL. For microshear bond strength assessment, samples were subjected to various treatment modalities and then bonding and debonding procedure was performed for blocks of composite and values were recorded. RESULTS: Significant reductions in S. mutans were observed in all the groups - Group I (DAE) 68.50%, Group II (LLL) 55.90%, Group III (MB + L) 88.60%, and Group IV (DAE + L) 87% with comparable bacterial reduction between Group III (MB + L) and Group IV (DAE + L). Furthermore, a significant difference in bond strength values was seen in Group III (MB + L) 10.99 MPa and Group IV (DAE + L) 17.99 MPa whereas an insignificant difference was found between Group I (DAE) 20.74 MPa, Group II (LLL) 18.27 MPa, and Group IV (DAE + L). CONCLUSION: DAE caused a comparable reduction in bacterial count to MB-assisted PDT and also there was no adverse effect on bond strength values. PDT can be performed while acid etchant containing MB dye is being applied in the cavity, thus reducing operative time and enhancing cavity disinfection.

Evaluation of the effect of natural versus synthetic matrix metalloproteinase silencers in preservation of dentin collagen and long-term bond strength of total etch adhesive.

AIM: This study investigated the effect of various synthetic (galardin [Gal] and benzalkonium chloride [BAC]) and natural agents (hesperidin [HES] and epigallocatechin gallate) on the stability of dentin collagen matrix to resist collagenase degradation and improve long-term microtensile bond strength. MATERIALS AND METHODS: Ten sound-impacted third molars were collected and manual removal of pulp, periodontal ligament, cementum, and enamel was done. Remaining dentin fragments were pulverized under liquid nitrogen to obtain dentin powder. 2 mg aliquot of dentin powder was allocated to each of the test solutions and subjected to hydroxyproline assay. Another 60 sound human third molars were collected and occlusal enamel was ground flat to reach dentinoenamel junction. Class I cavities were prepared in dentin, followed by etching using 37% phosphoric acid for 15 s. Samples were then subjected to surface treatment with different agents for 60 s, followed by application of Optibond S and restoration with P 60 composite resin. Samples of all groups except control were subject to thermocycling. Samples were sectioned to 1 mm thick slabs which were subject to universal testing machine to determine ultimate tensile strength. One-way analysis of variance and Bonferroni post hoc test with a significance level of P < 0.05 were used to analyze data. RESULTS: HES resulted in maximum resistance to collagen degradation, followed by epigallocatechin gallate (EGCG), Gal, and BAC with a significant difference among the groups. Samples of Gal group showed the highest microtensile bond strength values, followed by HES, EGCG, BAC with a significant difference between the groups except HES and EGCG where the difference was nonsignificant. CONCLUSION: The use of matrix metalloproteinase silencers could improve the mechanical properties of collagen and resist enzymatic degradation, leading to an improved long-term intimate restoration.

Influence of type of cement and their thickness on stress distribution at dentin-cement interface of computer-aided designed glass fiber post: A three-dimensional finite element analysis.

AIM: This study aims to evaluate the effect of type of cement, and their thickness on stress distribution at dentin-cement interface of computer-aided designed glass fiber post using three-dimensional finite element analysis. MATERIALS AND METHODS: Nine 3D models of endodontically treated maxillary second premolar were divided into three groups according to the adhesive cement used PermaCem (Group I), Variolink II (Group II), and ParaCore (Group III). Each group was further divided into subgroup a, b, and c on the basis of the thickness of the adhesive cement 50 µm, 200 µm, and 300 µm, respectively. All the models were simulated to be cemented with computer-aided designed glass fiber post and core followed by zirconia crown. The core was modeled with incomplete ferrule. The load of 200N at 45° at lingual and central fossa was applied. Maximum von Mises stresses distribution was calculated. RESULTS: Maximum and minimum stresses in dentin were seen in the Ic and IIIa, respectively. Maximum and minimum stresses in cement were seen in IIIc and Ia, respectively. CONCLUSION: The von Mises stresses in dentin can be minimized by keeping the cement thickness minimum and selecting the cement whose modulus of elasticity is closest to that of dentin.

Evaluation of the effect of calcium hydroxide and endodontic irrigants on the push-out bond strength of fiber post - an in vitro study.

BACKGROUND: In recent years, fibre-reinforced composite posts have been proposed for the restoration of root filled teeth as an alternative to pre-fabricated posts or metal dowels. AIMS AND OBJECTIVES: The aim of the study was to analyze the effect of endodontic irrigants used for removal of calcium hydroxide on the push-out bond strength of fiber posts to root canal dentin. METHODS: Forty human permanent single-rooted mandibular premolars with relatively straight roots were taken and access cavities were prepared and biomechanical preparation done using Rotar Y protaper file till size F2. The samples were divided into Experimental group and Control group. In Experimental groups Intracanal dressing of calcium hydroxide was removed by 2.5% NaOCl and 17% EDTA (Group1), MTAD (Group II) and Qmix (Group III). Control group did not receive Intracanal calcium hydroxide dressing. Canals were obturated using size F2 protaper gutta-percha points and AH plus sealer. After storage for 24 hours, post space was prepared. Forty Tenax fiber post (Coltene) were cemented with Rely X U200 resin. The roots were then transversally sectioned into 3 slices of 1mm thickness corresponding to cervical, middle and apical third. The slices obtained were subjected to micro-push-out bond strength test using a universal testing machine. The data obtained was subjected to statistical analysis using One-Way ANOVA test. P value of .05 was considered as statistically significant level. RESULTS: The mean push-out bond strength values for controls, NaOCl/EDTA, MTAD and QMIX group at cervical third were 10.17, 15.84, 20.39 and 20.98 whereas at apical third 4.78, 8.85, 11.66 and 12.10. CONCLUSION: Qmix showed higher push-out bond strength values followed by MTAD and NaOCl/EDTA. All the groups showed lowest push-out bond strength values in the apical third followed by middle and the maximum in the cervical region.

Efficacy of different irrigation regimes on the push-out bond strength of various resin-based sealers at different root levels: An in vitro study.

AIM: This study aims to evaluate and compare the efficacy of various irrigation regimens on push-out bond strength of AH Plus/gutta-percha, Real Seal/Resilon, and MetaSeal/gutta-percha at three different root levels. MATERIALS AND METHODS: Single-rooted mandibular premolars (n = 120) were prepared and divided into four groups (n = 30) based on irrigation regimen used: I: 5.25% sodium hypochlorite (NaOCl)-17% ethylenediaminetetraacetic acid (EDTA); II: 5.25% NaOCl-2.25% Peracetic acid (PAA); III: 5.25% NaOCl-18% 1-hydroxyethylidene-1, 1-bisphosphonate (HEBP) (Etidronic Acid); and IV: Distilled Water. Each group was further divided into three subgroups (n = 10); A: AH Plus/gutta-percha; B: MetaSEAL/gutta-percha; C: RealSeal/Resilon. After obturation, roots were sectioned at 3 levels and push-out tests were performed. One-way ANOVA with post hoc Tukey-honestly significant difference tests were applied to assess the significance among various groups. RESULTS: Among irrigants, 2.25% PAA showed significantly lower values when compared with rest of the irrigants. There was no significant difference found among EDTA and HEBP. The push-out bond strength of AH Plus was significantly higher among all sealers. The bond strength values were significantly decreased in apico-coronal direction. CONCLUSIONS: There was superior efficacy of EDTA and HEBP on the bond strength of AH Plus at apical root level when compared with other irrigants and sealers at various root levels.

Effect of different antioxidants on reversing compromised resin bond strength after enamel bleaching: An in vitro study.

OBJECTIVE: The effect of 10% sodium ascorbate, 10% α-tocopherol, 10% grape seed extract, and 10% guava seed extract solutions on the shear bond strength (SBS) of composite resin to bleached enamel was evaluated. MATERIALS AND METHODS: Labial enamel surfaces of 72 extracted maxillary central incisors were bleached using 37.5% hydrogen peroxide. Sixty-four specimens were divided into four experimental groups (Group I-IV) comprising 16 specimens each and remaining eight specimens were placed in Group V. Groups I-IV were further divided into 2 subgroups: A (10 min) and B (120 min) comprising 8 specimens each. Eight unbleached specimens served as control (Group VI). Immediately following bleaching, Groups IA-IVA and IB-IVB specimens were treated with respective antioxidants for 10 min and 120 min. All specimens were then bonded with composite resin. Specimens were stored in distilled water for 24 h. SBS testing was done. Data were tabulated and subjected to statistical analysis using ANOVA and Tukey's honest significant difference test. RESULTS: Group VI (unbleached) showed the highest SBS followed by Group IV (10% guava seed extract). CONCLUSION: Use of antioxidants effectively reversed the compromised bond strength of bleached enamel. About 10% guava seed extract application after bleaching showed best bond strength.

Effect of potential remineralizing agent and antioxidants on color stability of bleached tooth exposed to different staining solutions.

AIM: The aim of the study was to evaluate the effect of staining solutions, remineralizing agent, and antioxidant on color stability of tooth during and after bleaching. MATERIALS AND METHODS: Ninety human central incisors were bleached using 35% hydrogen peroxide (Pola office) and allocated to three groups (n = 30). Group I stained with cola-based soft drinks, Group II stained with pomegranate juice, and Group III stained with turmeric. The groups were then divided into three subgroups (n = 10): subgroup A - control (artificial saliva), subgroup B - remineralizing agent (Vantej), and subgroup C - antioxidant (grape seed extract [GSE]). Specimens were bleached according to the manufacturer's recommendations. Color variation measurement was performed using a photoreflectance spectrophotometer before bleaching, during each bleaching session (2-times/week), and after (7 and 15 days) the cessation of bleaching. Artificial saliva was used as the storage medium for the specimens except when measurements were to be recorded. The results were then subjected to statistical analysis. RESULTS: Freshly bleached teeth exposed to Vantej and GSE and significantly lowered the stain absorption. CONCLUSION: Among the experimental agents, Vantej performed statistically better at all time intervals.

To evaluate and compare the effect of different light-curing modes and different liners on cuspal deflection in premolar teeth restored with bulk filled or incrementally filled composite measured at different time intervals.

AIM: The aim of this study is to evaluate and to compare the effect of different light-curing modes and different liners on cuspal deflection in premolar teeth restored with bulk filled or incrementally filled composite measured at different time intervals. MATERIALS AND METHODS: The study was divided into two parts (Part 1-different curing modes, Part 2-different liner) each with sixty extracted human upper premolar teeth with standardized large mesio-occlusal-distal cavities prepared. Each part was divided into two groups according to the composite used (Group A-Filtek Z350 XT, Group B-Sonic fill). Each group was then divided into three subgroups according to the light-curing modes (soft-start, pulse, and continuous curing mode) and liner (Filtek Z350 XT Flowable, Vitremer) used. The cuspal deflection was then measured with a digital micrometer gauge and subjected to statistically analysis using analysis of variance and Tukey's post hoc test. RESULTS: Sonic fill composite, resin-modified glass ionomer cement (RMGIC) liner and curing with soft-start/pulse curing mode had significantly lower cuspal deflection compared to Filtek Z350 XT, flowable liner, and continuous curing mode, respectively. CONCLUSION: Sonic fill composite, RMGIC liner under the restorations and composites cured with soft start/pulse curing mode resulted in reduced cuspal deflection.

Effect of saliva and blood contamination on the shear bond strength of fifth-, seventh-, and eighth-generation bonding agents: An in vitro study.

AIM: To evaluate the bond strength of different adhesives after contamination with saliva and blood at various steps of application. MATERIALS AND METHODS: Buccal surfaces of 180 human premolars were sliced to expose dentin. The specimens were randomly divided into six groups (n = 30), in which saliva and blood were used as contaminants in three groups each. The groups were further divided according to the generation (fifth - OptiBond Solo Plus Kerr, USA; seventh - OptiBond All-In-One Kerr, USA; eighth - Futurabond DC, Voco, Germany) of the adhesive used. Effect of contaminant application both before and after polymerization of the adhesive was evaluated. Composite cylinders were fabricated on exposed dentinal surfaces and were subjected to shear bond strength test. The results were subjected to one-way analysis of variance and t-test. RESULTS: The eighth-generation adhesive showed the highest mean shear bond strength, followed by fifth- and seventh-generation adhesive. Salivary contamination resulted in greater decrease of bond strength when contaminated before polymerization. However, the results were vice versa when blood contamination was done, except in the case of fifth-generation adhesive. Blood contamination produced the lowest shear bond strength in all conditions. CONCLUSION: The eighth-generation adhesives showed the highest and blood contamination the lowest bond strength in all conditions.

Effect of ceramic type, thickness, and time of irradiation on degree of polymerization of dual - cure resin cement.

AIM: The aim of the study is to evaluate the effect of ceramic type, thickness, and time of irradiation on degree of polymerization of dual-cure resin cement. MATERIALS AND METHODS: Dual-cure resin cement (SoloCem) was used to prepare disk-shaped samples (0.5 mm thick × 5 mm diameter). Study group samples (n = 5) were light-cured for 40, 60, and 80 s through all ceramic leucite-reinforced (Cergo Kiss), lithium disilicate-reinforced (IPS e.max), and monolithic zirconia-reinforced (Ziecon) of three thicknesses (2, 3, and 4 mm). Negative control group samples were cured through metal disks and positive control samples were cured without the presence of ceramic. The degree of conversion (DC) was evaluated by Fourier transform infrared spectrometer. The recorded data were subjected to one-way analysis of variance, followed by post hoc analysis (Tukey HSD). RESULTS AND CONCLUSION: Greatest light transmission and DC were seen through Cergo Kiss, followed by IPS e.max Press and Ziecon, with insignificant difference between the latter two. The attenuation of light irradiance increased with increasing thickness of ceramic disks, with statistically significant values between 3 and 4 mm. Increasing time of irradiation to cure dual-cure resin cement did not always result in greater degree of polymerization.