Aim: The aim is to review and discuss the strategies available for the regeneration of tooth tissues based on principles of tissue engineering. Background: Tissue engineering is a multidisciplinary approach that aims to regenerate functional tooth-tissue structure based on the interplay of three basic key elements: Stem cells, morphogens and scaffolds. A number of recent clinical case reports have revealed the possibilities that many teeth that traditionally would be treated byapexification may be treated by apexogenesis. Materials and Methods: Electronic and hand search of scientific papers were carried out on the Entrez Pubmed, and the Cochrane Central Register of Controlled Trials databases using specific keywords. Specific inclusion and exclusion criteria were predetermined. The search yielded 1619 papers; out of which 65 were identified as conforming to the predetermined inclusion criteria and the remaining 1554 were excluded. Out of 65 papers, 34 papers were excluded again as different key words led to the same publications. Only 31 papers were selected, out of which 27 full-text papers were found and 4 papers were included based on only the abstracts. These 31 papers formed the basis of this review. The data were extracted from the selected studies. The data were synthesized by pooling the extracted data. Conclusion: The field of tissue engineering has recently shown promising results and is a good prospect in dentistry for the development of the ideal restorations to replace the lost tooth structure.

Background: Enamel demineralization resulting in White Spot Lesion (WSL) is one of the most common disease outcome associated with fixed orthodontic therapy with high prevalence rates in western countries. However, no such studies have been done on Indian population. Aim: The aim of this study was to evaluate the prevalence of WSLs in a section of urban Indian population between the age group of 12-20 years undergoing fixed orthodontic therapy for a period of 12-15 months. Materials and Methods: 180 patients who qualified for this study were examined and evaluated for WSLs: Group I (test group) comprised of 90 subjects who were undergoing orthodontic treatment for a period of 12-15 months; Group II (control group) comprised of 90 subjects who were in need of orthodontic treatment. Results: The result showed a high prevalence rate of 75.6% in Group I compared to 15.6% in Group II. Conclusions: The study elicited significantly higher prevalence rate of WSLs in Indian patients undergoing fixed orthodontic treatment.

Aim: The objective of the present study was to evaluate and compare the wetting behavior of three different root canal sealers on the root canal dentin surface treated with irrigants and their combination. Materials and Methods: Decoronation and apical third resections of 27 extracted single-rooted human mandibular premolars were done. The roots were then split longitudinally into two halves, and randomly assigned into three treatment groups (n=18). The root dentin surfaces in Group1, Group 2 and Group 3 were treated with 17% ethylene diamine tetra acetic acid (EDTA), 3% sodium hypochlorite (NaOCl) and combination of 17% EDTA and 3% NaOCl, respectively. Each group was subdivided into three subgroups of 6 specimens each, depending on the the sealer used, i.e. sub group A. zinc oxide (ZnOE), sub group B. AH plus, subgroup C. Guttaflow sealer, respectively. The contact angle was measured using First Ten Angstroms (FTA) 200 dynamic contact angle analyzer. Results: The contact angle values for AH Plus sealer were significantly lower when compared to the other two sealer groups. Conclusion: The wettability of AH Plus sealer on the root surface dentin was found to be better than Gutta-Flow and ZnOE sealer.

Background: The aim of this study was to investigate whether the smear layer influences the removal of calcium hydroxide from the root canal with manual or rotary instruments. Materials and Methods: The root canals of 48 freshly extracted single-rooted maxillary incisors were prepared to apical size 40 (n=40) and finally irrigated with sodium hypochlorite (group A), or ethylene diamine tetra acetic acid (EDTA) followed by sodium hypo chlorite (group B). 20 teeth were assigned to each group, while the remaining eight teeth served as positive and negative controls. Each group was divided into two subgroups of 10 teeth (subgroup I - calcium hydroxide was removed with master apical file; subgroup II - with profile file); and, in all removal procedures, citric acid was used for irrigation. The percentage of calcium hydroxide-[Ca(OH) [Ca(OH) ₂ ] coated surface area was calculated by image processing analysis. Results: Considering the root canal as a whole, the removal of Ca(OH) ₂ from the dentinal walls in group B showed significantly better results (P<0.05) as compared to group A. Conclusions: Under the conditions of this study, it can be concluded that the smear layer is important in the removal of calcium hydroxide.

Objectives: The objective of this study was to evaluate the effectiveness of manual, sonic-air and ultrasonic instrumentation with varying irrigation protocols on removal of the smear layer from root canal walls. Study Design: Sixty extracted single rooted human teeth stored in 0.5% saline were used. Periodontal soft tissues were removed followed by crown separation at the cementoenamel junction (CEJ). All the teeth were randomly divided into three groups. Group I was manually instrumented and irrigated with 5.25% sodium hypochlorite (NaOCl) alone and 17% Ethylenediaminetetraacetic acid (EDTA) alternately, same as sonically instrumented Group II and ultrasonically instrumented Group III. The controls for all groups were irrigated with saline solution. Results: Ultrasonic over the sonic-air and manual technique, and the use of a combination of two different solutions (17% EDTA and 5.25% NaOCl) alternatively yielded better outcome. Conclusions: Ultrasonic, sonic-air and manual instrumentation of the root canal and irrigation with combined solutions is effective in removal of the smear layer from the instrumented walls of the root canal.

Aim: To compare push-out bond strength between self-cured and dual-cured resin cement using a titanium post. Background: Dual-cured resin cements have been found to be less polymerized in the absence of light; thus the bond strength of cements would be compromised due to the absence of light with a metallic post. Materials and Methods: Ten extracted teeth were prepared for cement titanium PARAPOST, of five specimens each, with Panavia F [dual-cured (PF)] and Rely×Luting 2 [self-cured resin-modified glass ionomer luting cement (RL)]; the push-out bond strength (PBS) at three different levels of the sectioned roots was measured. The failure modes were observed and the significance of the differences in bond strength of the two types of cement at each level and at different levels of the same type was analyzed with non-parametric tests. Results: The push-out bond strength of the RL group was greater at all the three levels; with significant differences at the coronal and middle levels (P<0.05). No significant differences in PBS at different levels of the same group were observed. Cement material around the post was obvious in the PF group. The failure mode was mostly adhesive between the post and resin cement in the RL group. Conclusion: Bond strength was greater with self-cured, resin-modified glass ionomer luting cement, using titanium post.

Aim: The purpose of this study was to clarify detection characteristics of the secondary mesio-buccal canal in maxillary first molars using various methods. Materials and Methods: The root canal system of 86 extracted human maxillary first molars was inspected using micro-focus-computed tomography to accurately determine the number of canals. Radiographs or floors of the pulp chamber for all samples were observed for the secondary mesio-buccal canal with computed tomography for dentistry, digital dental radiography, magnifier, or the naked eye. Sensitivity, specificity, positive, and negative predictive values and diagnostic accuracy for these four methods were investigated using the results from the micro-focus-computed tomography inspection as the gold standard. All samples of each method were observed by 10 endodontists. Using these results, the χ² test was used to compare and analyze differences between the various conditions (P<0.05). Results: The secondary mesio-buccal canal could be recognized in 60.9% of samples with the micro-focus-computed tomography. No significant difference was seen between efficiencies of the computed tomography for dentistry and the micro-focus-computed tomography. The computed tomography for dentistry was superior to the other three methods. Conclusion: Detectability of the secondary mesio-buccal canal in the maxillary first molar was superior using dental-computed tomography compared to digital dental radiography, magnification telescope, and the naked eye.

Aim: This study assessed the effect of the dentin depth and the application mode on the hardness and elastic modulus of the adhesive layer. Materials and Methods: Occlusal surfaces of 48 caries-free human third molars were removed, at two levels: Superficial and deep dentin. For each type of surface, the test specimens were randomly divided into groups which underwent the application: A conventional two-step adhesive system (Adper™ Single Bond [SB]) and self-etch adhesives system (Adper™ SE Plus [SE] and AdheSE^® [AD]). The adhesives applied were active or passive. Composite build-ups were constructed incrementally. The teeth were sectioned, embedded, and polished. The nanoindentation test was performed in the adhesive layer. The results were analyzed by ANOVA and Tukey tests. Results: In the adhesive layer, the higher hardness (0.307 ± 0.006 GPa) and elastic modulus (4.796 ± 0.165 GPa) of SE were obtained in superficial dentin in passive application. The elastic modulus of SE (4.115 ± 0.098 GPa) was lowest in active application in superficial dentin. The active application significantly increased the hardness of the SB in the deep dentin (0.011 ± 0.314 GPa) compared the superficial dentin (0.280 ± 0.010 GPa). For the AD, only the mode of application was statistically significant (P=0.0041) for the hardness, active application (0.289 ± 0.015 GPa) being higher than passive application (0.261 ± 0.013 GPa) (P=0.0042) in deep dentin. Conclusion: The experimental results reveal that the mechanical properties were influenced for the application mode of adhesive systems and dentin depth.

Aim: The aim of this study is to evaluate the surface roughness of four flowable resin composites following exposure to acidic and alcoholic drinks. Materials and Methods: SureFil SDR flow, TetricEvoFlow, Esthet-X Flow and Amaris Flow HT samples were immersed in artificial saliva, Coca Cola and Chivas Regal Whisky. Each specimen was examined using a Leica DCM 3D microscope: Arithmetical mean height of the surface profiles was measured (Sa). Results: Kruskal-Wallis test showed significant differences among various groups (P<0,001). Mann Whitney test was applied and control groups showed significantly lower Sa values than other groups (P=0,008). Coca Cola groups showed highest Sa values (P<0,021). No significant differences (P=0,14) in surface texture were found among the specimens of the different materials. No significant differences were found among TetricEvoFlow, Esthet-X Flow and Amaris Flow under control conditions nor after Coca Cola application. Under control condition and after Coca Cola application SureFil SDR flow showed significantly higher Sa values. Moreover, after whisky application Amaris Flow showed significantly lower Sa values then the other three groups that showed no significant differences among them. Conclusions: Acidic and alcoholic drinks eroded the surface roughness of all evaluated flowable resin composites.

Background Aim: The purpose of this study was to compare and evaluate the dissolving capability of various endodontic solvents used during endodontic retreatment on resilon and gutta-percha at different immersion time intervals. Materials and Methods: 160 ISO no. 40 cones (0.06 taper), 80 each of resilon and gutta-percha were taken as samples for the study. Both resilon and gutta-percha were divided into eight experimental groups of 20 cones (four groups each of resilon and gutta-percha) for immersion in xylene, tetrachloroethylene, refined orange oil and distilled water. Each group was further divided into two equal subgroups (n=10) for 2- and 5-minute immersion time intervals at room temperature to investigate the potential of these solvents for clinical use in dissolving resilon and gutta-percha. Each sample was weighed initially before immersing in the solvent on a digital analytical scale. Distilled water served as a control. Samples were removed from the respective solvents after the specified immersion period and washed in 100 ml of distilled water and allowed to dry for 24 h at 37°C in a humidifier. The samples were then again weighed after immersion in the specific solvent on a digital analytical scale. The extent of gutta-percha or resilon removed from the specimen was calculated from the difference between the original weight of gutta-percha or resilon sample and its final weight. Means and standard deviations of percentage loss of weight were calculated at each time interval for each group of specimens. The values were compared by statistical parametric tests using SPSS 16.0 Software. The data was subjected to paired 't ' test, independent 't' test, one-way ANOVA test and multiple comparisons with Scheffe's test. Results: There was no significance in the amount of gutta-percha dissolved at 2- and 5-minute immersion time intervals in all groups (P>0.05) except the tetrachloroethylene group (P=0.00). There was a very high significance in the amount of resilon dissolved at 2- and 5-minute immersion time intervals in all groups (P=0.00) except the xylene and distilled water (Control) groups (P>0.05). Conclusion: The results showed that xylene, refined orange oil and tetrachloroethylene can be used for softening gutta-percha/resilon during retreatment with various techniques- xylene being the best solvent both for gutta-percha and resilon.

Aim: The aim of this study is to compare the occurrence of enamel fractures, sealant fractures and marginal fissures after placement of three sealants: Helioseal F, Conseal F and Clinpro. Materials and Methods: Thirty individuals between 13 and 15 years of age, diagnosed with pit and fissure caries by visual and DIAGNOdent examination, were chosen for sealant placement on their mandibular molars. The sealants were placed at random, after which, impressions were made with polyvinyl siloxane and casts were fabricated. Dies were prepared, each of which were sputter coated with gold in order to be examined under a scanning electron microscope. The following morphologies were analyzed from dies from each of the sealant groups: Continuous margins, sealant fractures, marginal fissures and enamel fractures. After six months, they were recalled for impression making. Dies were prepared and microscopically analyzed as mentioned. Based on the time of evaluation, there were two groups: Initial group (soon after placement) and final group (after six months). Statistical analysis was done using the paired 't' test and One-way analysis of variance (ANOVA). Results and Conclusions: Clinpro had the greatest fracture resistance, followed by Conseal F and Helioseal F. The occurrence of marginal fissure was found to be least with Clinpro.

Aim: The purpose of this study is to evaluate the resin-dentin interface, quality of the hybrid layer of total-etching and self-etching adhesive systems under scanning electron microscopy (SEM). Materials and Methods: Class V cavities were prepared in 40 extracted human molars. In Group I XP bond (Dentsply), in Group II Adper Single Bond II (3M ESPE), in Group III Adper Easy One (3M ESPE), and in Group IV Xeno V (Dentsply) were applied. Teeth were restored with resin composite, subjected to thermocycling, and sectioned in Buccolingual plane. The samples were demineralized using 6N HCl, for 30 sec, and deproteinized with 2.5% NaOCl for 10 min, gold sputtered, and viewed using a scanning electron microscope. Results: Among the total-etch systems used, the XP Bond showed a clear, thick hybrid layer, with long resin tags and few voids. Among the self-etch adhesive systems, the Xeno V did not show a clearly recognizable hybrid layer, but there were no voids and continuous adaptation was seen with the dentin. Conclusion: The adaptation of self-etch adhesives to the resin-dentin interface was good without voids or separation of phases; showing a thin, continuous hybrid layer.

Introduction: The purpose of obturation of the prepared root canal space is to prevent coronal leakage and bacterial contamination and to seal the apex from the periapical tissue fluids. Cold lateral technique has been considered to be a gold standard, however considering its limitations various thermoplasticized gutta-percha techniques have been recommended. This study compares radiographic quality of obturation in molar teeth, obturated with cold lateral condensation and thermoplasticized injectable gutta-percha technique (Obtura II system). Materials and Methods: Sixty patients were equally divided into two groups, Group A obturated with Cold lateral condensation technique and group B with Obtura II. Periapical radiographs were obtained immediately after the obturation using paralleling device method. The radiographs were examined by an observer, who was blinded to the group allocation. Data was compared using χ² (Chi square) test and Independent sample t test was used to compare the mean ages. Results: Both groups were comparable in all respects such as tooth type, preoperative diagnosis and preoperative pain (P>0.05); however, more pre-operative radiolucency cases were allocated to Obtura II (P<0.05). There was no difference between the two groups, both in terms of postoperative voids as well as apical termination of the obturation (P>0.05). Conclusion: Within the limitations of the study, it was found that statistically there was no significant difference between cold lateral and obtura II technique, in terms of post obturation voids and apical termination, as observed in radiographs.

Aim: The aim of this study is to evaluate the residual monomer content and polymerization shrinkage of a packable composite (Surefil) and an ormocer (Admira). Materials and Methods: The study was conducted in two parts. In Part I, 10 samples of each material were prepared in a standardized split brass mould, using incremental curing technique. The residual monomer content was measured by observing change in weight before and after Soxhlet Extraction procedure. In part II, the volumetric polymerization shrinkage was calculated by measuring the difference in specific gravities of 10 uncured and 10 cured samples of each material using a modified version of ASTM D-792 method. The data obtained was put to statistical analysis using student's 't' test. Results: Part I - The percentage change in weight for Surefil was 0.525% while that for Admira was 0.374%, which was found to be statistically significant. Part II - The volumetric percentage shrinkage for Surefil ranged between 1.04-3.42% and that for Admira between 1.01-2.31%, which was not found to be significant statistically. Conclusion: Admira may be considered more biocompatible than Surefil due to the lower residual monomer content in the former; however, both are comparable with regards to their polymerization shrinkage.

Aims/Objectives: To evaluate the effect of glass and polyethylene fiber inserts and flowable composite as a liner on the microleakage of Class II composite restorations with gingival margins on root surfaces. Materials and Methods: Class II slots were prepared on both the proximal sides of thirty freshly extracted mandibular molars and were divided into six groups, according to the type of fiber insert and use of flowable composite (Filtek Z350) as a liner. Filtek P-60 (3M/ESPE) posterior composite was used to restore all cavities. The specimens were thermocycled and stained with 2% Basic Fuchsin dye, and sectioned to evaluate the dye penetration under Stereomicroscope. Statistical analysis was done using Kruskalwallis test and Mann whitney U test. Results and Conclusion: This study showed that, fiber insert groups, with or without flowable liner, had reduced microleakage scores as compared to the control groups. However, statistically no significant difference was found between the groups with fiber inserts. Less microleakage was seen in Group IV (With flowable liner and without Fiber inserts) as compared to Group I (Without flowable liner and Fiber inserts).

Context: Evaluation of microhardness of root dentin provides indirect information on the change in mineral content of root dentin thereby providing useful information on the bonding quality of resin-based root canal sealers. Aims: This study evaluated the effect of 17% EDTA, MTAD, and 18% HEBP solutions on the microhardness of human root canal dentin using the Vickers microhardness test. Materials and Methods: Forty human single-rooted teeth were decoronated at the cementoenamel junction and sectioned longitudinally into buccal and lingual segments. Eighty specimens were divided into four groups (n=20). Group I was treated with distilled water (control), groups II, III, and IV were treated with 1.3% NaOCl as a working solution for 20 minutes followed by 17% EDTA, MTAD, and 18% HEBP respectively. The surface hardness of the root dentin was determined in each specimen with a Vicker's hardness tester. The values were statistically analyzed using the one-way ANOVA and post hoc Tukey multiple comparison tests. Results: There was a statistical significant difference among all the groups (one-way ANOVA; P<0.001). Among the experimental groups, HEBP showed the highest dentin microhardness (53.74 MPa, P<0.001). Least microhardness was found with MTAD (42.85 MPa, P<0.001). Conclusions: HEBP as a final rinse appears to be a promising irrigation protocol with less impact on the mineral content of root dentin.

Aim: The purpose of this in vitro study was to evaluate the ultrastructural changes of dentin induced after exposure to different intracoronal tooth bleaching agents. Materials and Methods: Dental discs of 1 mm thickness were prepared from coronal dentin of sixty-four human maxillary premolars. Experimental specimens were divided into four subgroups: 45% carbamide peroxide, 35% hydrogen peroxide, sodium perborate + 30% hydrogen peroxide, sodium perborate + water. The specimens were then evaluated under scanning electron microscope to determine diameter of dentinal tubules and chemical analysis. Results: There was significant difference between dentinal tubule diameter of all test and control groups with the exception of sodium perborate + water. Chemical analysis revealed that there was no significant difference between experimental subgroups regarding calcium and sulfur wt%. Conclusions: All bleaching agents increased dentinal tubule diameter and promote alterations in mineral content of dentin with the exception of Sodium perborate mixed with water.

Aim: This study was designed to compare the accuracy of Root ZX and SybronEndo Mini, electronic apex locators (EALs), in the presence of various irrigants. Materials and Methods: Sixty extracted, single-rooted human teeth were decoronated and the root canals coronally flared. The actual length (AL) was assessed visually and teeth mounted in the gelatin model. The electronic length (EL) measurements were recorded with both EALs in the presence of 0.9% saline; 1% sodium hypochlorite (NaOCl); 2% chlorhexidine digluconate (CHX), and 17% EDTA solution, at "0.5" reading on display. The differences between the EL and AL were compared. Results: The accuracy of EL measurement of Root ZX and Sybron Mini within±0.5 mm of AL was consistently high in the presence of NaOCl and found to be least with EDTA. Conclusion: EL measurements were shorter with 1% NaOCl, whereas longer with 2% CHX for both the devices. Sybron Mini was more accurate with 1% NaOCl and 2% CHX than Root ZX.

Aim: This study was designed to comparatively evaluate the effect of cyclic loading on the retention of custom-fabricated fiber-reinforced composite (CF-FRC), prefabricated metal, and glass fiber posts. Materials and Methods: Thirty mandibular first premolars decoronated at the CE junction were divided into three groups (n=10). Groups A, B, and C were restored using Para Post (Whale dent), Reforpost (Angelus), and CF-FRC post (Ribbond-THM), respectively. Five specimens from each group were subjected to cyclic loading. Tensile bond strength (TBS) was evaluated. Results: Pre-loading TBS values were statistically, significantly higher for all posts (P<0.05). Before and after loading, there was a significant difference between group C as compared to groups A and B. Conclusions: Cyclic loading reduced the retention of all posts but was comparatively lesser for the CF-FRC post. This system provides sufficient retention required for clinical success.

The second premolars have the highest incidence of congenital absence, after the third molars. The problem resides not in the prevalence of congenitally missing premolars but in the selection of a treatment plan that will yield the best results over the long term. The present study reports a case of a 14 year old female patient with bilaterally congenitally missing second mandibular premolars with associated crowding of teeth. The case has been managed using a multi-speciality approach, in which both deciduous mandibular second molars were sectioned and the distal half retained. The retained half was prepared to receive a full coverage restoration which was contoured as a premolar. The space created was then utilized to correct the crowding by fixed orthodontics. A two year follow up shows retained distal half of the deciduous mandibular second molar with correction of crowding and space closure.

The aim of this study is to present a report of a case where forced orthodontic extrusion and computer-aided design and computer-aided manufacturing (CAD/CAM) technique was used for reconstruction of right maxillary central incisor with grossly destructed crown. Aesthetic rehabilitation of a fractured maxillary right central incisor was performed employing a multidisciplinary approach i.e. conventional endodontic treatment followed by orthodontic extrusion and final restoration using CAD-CAM and one piece milled zirconia post and core with full coverage zirconia crown. After the procedure being completed, periapical radiographs taken at 3 month follow up period demonstrated that the post and core remained well adapted to post space and there was a complete healing of periapical lesion. This technique can provide a complete aesthetic rehabilitation of a grossly destructed tooth without hampering the biological width and thus has a better prognosis.

Immature teeth with necrotic pulp and periapical lesion are difficult to treat via conventional endodontic therapy. Numerous procedures and materials have been utilized to induce root-end barrier formation. Traditionally, calcium hydroxide has been the material of choice for the apexification of immature permanent teeth; however, Mineral Trioxide Aggregate holds significant promise as an alternative to multiple treatments with calcium hydroxide. One of the technical problems associated with the placement of the restorative materials used as artificial barrier is to prevent overfill and underfill. Using a matrix avoids the extrusion of the material into the periodontal tissues. This case report presents the successful healing and apexification with combined use of Mineral Trioxide Aggregate as an apical barrier, and autologus platelet rich fibrin membrane as an internal matrix.