Recent studies suggest that Stem Cells being used for a number of regenerative diseases. Stem cells can self-renew and produce different cell types, thus providing new strategies to regenerate missing tissues and treat diseases. In the field of dentistry, adult mesenchymal stem/stromal cells (MSCs) have been identified in several oral tissues, which suggests that the oral tissues are a rich source of stem cells, and oral stem and mucosal cells are expected to provide an ideal source for genetically reprogrammed cells such as induced pluripotent stem (IPS) cells. Furthermore, oral tissues are expected to be not only a source but also a therapeutic target for stem cells, as stem cell and tissue engineering therapies in dentistry continue to attract increasing clinical interest. With appropriate biochemical signals stem cells can be transformed into desirable cells. The idea behind this article is to shortly review the obtained literature on stem cell with respect to their properties, types and advantages of dental stem cells. Emphasis has been given to the possibilities of stem cell therapy including regeneration of tooth and craniofacial defects.

Musculoskeletal disorders (MSD) represent an important occupational health issue in dentistry. Prolonged static postures, repetitive movements, excessive contraction of short muscles could cause musculoskeletal disorders. Even when the sitting posture is the one recommended by ISO, there is a high risk of developing musculoskeletal disorders. Each member of the dental team is predisposed to pain or injury in different areas of the body, depending on their tasks and position in relation to the patient. MSD is prevalent world over and is one of the commonest causes of long-term pain and disability affecting hundreds of millions of people. This article shows the causes and the mechanisms that lead to musculoskeletal disorders and some methods for prevention.

Objectives: This study was undertaken to evaluate the efficiency of two rotary nickel titanium instruments and hand instrumentation in removing gutta-percha and sealer from root canals. Study design: 63 extracted human single rooted premolars were instrumented with K-files and filled using lateral compaction of gutta-percha (GP) and three different sealers. The teeth were randomly divided into three experimental groups of 21 specimens each. Removal of gutta-percha was performed with R-Endo retreatment files, Mtwo retreatment files and Hedstrom files. Time to reach working length and to eliminate filling material was also recorded. The specimens were sectioned for evaluation of the area of the remaining gutta-percha/sealer under stereomicroscope at 6X magnification. Photographs were taken for further analysis using computer image analysis program. The results were statistically analyzed using Analysis of variance (ANOVA) and Tukey's honestly significant difference test. Results: The R-Endo retreatment system resulted in a smaller percentage of canal area covered by residual GP/sealer than in other groups, a significant difference was found between R-Endo and Mtwo group and between Hedstrom groups (P < 0.001). The Mean operating time was minimum with R-Endo group while it was found to be maximum with hand files. Conclusion: It was concluded that all test techniques left gutta-percha/sealer remnants within the root canal. The R-Endo retreatment files and Mtwo retreatment files system proved to be an efficient method for removing gutta-percha and sealer from single rooted premolars.

Fracture resistance of endodontically treated teeth restored with post. Aims: This study aims to compare the fracture resistance of endodontically treated teeth restored with resin fiber and stainless steel post. Commercially available prefabricated resin fiber post(Dentsply Maillefer Easy Post), prefabricated stainless steel post(Coltene/Whaledent Parapost) were used. Methods and Material: Forty five maxillary central incisors were obturated and divided into 3 groups: Control Group (Group I) without any post (n = 15), Resin Fiber Post Group (Group II) (n = 15) and Stainless Steel Post Group (Group III) (n = 15). In all Groups except control group, post space was prepared; a post was cemented, and a core build-up was provided. All the specimens were subjected to compressive force under a universal testing machine until fracture. Statistical analysis used: The results were analyzed using the variable analysis test (ANOVA). Results: One-way analysis of variance revealed significant difference among test groups. The control group demonstrated highest fracture resistance (925.2183 N), followed by the resin fiber post group (486.7265 N) and stainless steel post group (423.539N). Conclusions: Teeth restored with resin fiber post showed higher fracture resistance values than prefabricated stainless steel post.

To compare the condylar guidance values obtained from interocclusal records and the panoramic radiographs in both dentulous and edentulous subjects. Materials & methods: 20 dentulous and 20 edentulous subjects having specific criteria were selected for the cross-sectional descriptive in-vivo study. In the first method, the sagittal condylar guidance values for both the groups were recorded after obtaining protrusive records using HANAU articulator model Wide-Vue, U.S.A. In the second method panoramic radiographs were made of all the edentulous and dentulous subjects in the natural head position and tracings were done of the outline of glenoid fossa and the articular eminence. The angles formed by the lines drawn were measured and the values obtained were compared with those from the inter-occlusal record method. The condylar guidance readings of both dentulous and edentulous subjects obtained from the interocclusal records and those by tracing panoramic radiographic images were compared by Mann Whitney U test and Karl Pearson's coefficient of correlation test. Results: The condylar guidance values obtained from the interocclusal records were less when compared to the values obtained from tracing the panoramic radiographs. Significant correlation (r=0.9) between the condylar guidance values obtained for left and right sides in interocclusal record group and a moderate correlation (r=0.65) between the condylar guidance values obtained for left and right sides from panoramic radiographs. Conclusion: The results from this study showed that measurement of condylar inclination angles using panoramic radiographs gave higher values, as compared to the inter-occlusal record method. Also, panoramic radiographic method revealed less difference between the condylar guidance values obtained for left and right sides as compared to the articulator method. Although, significant amount of correlation was found between the two methods, variations due to different operators and better radiographic techniques should be further investigated.

Objectives: This study was conducted to evaluate stress pattern distribution in the periodontal ligament during various orthodontic tooth movements. Methods: A 3 dimensional FEM model of upper central incisor was developed from C.T scan images of the skull excluding the mandible. The principal stress obtained on the periodontal ligament due to various orthodontic loadings (tipping, bodily movement, intrusion, extrusion and rotations) were tested. Results: Intrusion, extrusion and rotation produced stresses concentrated at apex of root. Bodily movement and tipping forces produce stress concentrated at the alveolar crest and not at the root apex. Conclusion: Clinical implications of this study suggests that if the clinician is concerned about placing heavy stresses on the root apex then vertical and rotational forces must be applied with caution.

Microleakage is the clinically detectable passage of bacteria, fluids, molecules or ions between a cavity wall and the restorative materials applied to it. This study was conducted to evaluate and compare the microleakage in Class II nanocomposite restorations, with resin-modified glass ionomer liner(group I), nanofilled flowable composite liner(group II) & without liner(group III). Thirty six non carious upper premolar teeth extracted for orthodontic purposes were selected. Standard class II cavities were prepared. The teeth were then randomly & equally divided into three groups with 12 teeth in each group. The teeth were subjected to thermocycling. After that apex of each tooth was sealed with acrylic resin and the teeth were painted with two coats of nail varnish, except for the area of 2 mm from the periphery of the restorations. The coated teeth were immersed in buffered (Ph 7) 0.5% methylene blue dye for 48 hours. Teeth were sectioned & observed under stereomicroscope of 10X magnification. At gingival level, Group I exhibited slightly lesser microleakage than group II but was not statistically significant. Group I showed no significant difference between microleakage at occlusal and gingival level (Z=1.732; P=0.083). However, in Group II and Group III, there was significantly greater microleakage at the gingival level (Z= 2.162 and 3.162; P=0.002 and 0.002, respectively). Both resin-modified glass ionomer and flowable composite can be used as liners under nano composite restorations as reduction in microleakage was comparable.

Objective: To compare and evaluate the fracture resistance of endodontically treated molars reinforced with various bonded restorations and to study the type of fractures in various restorations. Methods: Forty extracted mandibular molars were endodontically treated. MOD (Mesio-Occluso-Distal) cavities were prepared and Mesio-Buccal cusp was reduced in all to provide cuspal coverage. All the teeth were then divided into 4 groups. The cavities in group 1(control) were filled with high copper amalgam. Group 2 was restored with direct resin composite. In group 3 after the priming and bonding procedures as in group 2, cavity surfaces were coated with flowable resin composite. Before curing a piece of polyethylene ribbon fiber was cut and coated with adhesive resin and was embedded inside the flowable composite. The resin composite was cured with visible light cure (VLC) gun. For group 4, restorations were done according to the recommendations provided by the manufacturers of SR Adoro (Ivoclar-Vivadent, Schaan, Liechtenstein) composite material. Compressive fracture strength test was performed after at least 24 hours of the fabrication of the specimens, by application of compressive loading in a Universal testing machine, applied on the occlusal aspect of each specimen with a steel bar. The mean loads necessary to fracture were recorded in Newton and the results were statistically analyzed. Results: Group 4 (indirect composite inlay) had the greater fracture resistance and group 1(Amalgam) had the poorest. Difference between group 1 and 3, group 1 and 4, group 2 and 4 were statistically significant. No statistically significant difference was found between group 1 and 2, group 2 and 3, group 3 and 4. Predominant type of fracture in group 1 and 3 was fracture of tooth below cemento enamel junction at tooth restoration interface without mesio buccal cusp involvement. In group 2 and 4, predominant fractures were of tooth below cemento enamel junction through center of restoration without mesio-buccal cusp involvement.

The breakthrough for dental laser systems came in the mid 1990's. Among the various laser types with corresponding wavelengths, diode laser systems quickly began establishing themselves as compact, competitively priced and versatile additions to the dentist's repertoire, predominantly for performing soft tissue applications. The advantages of laser use include a relatively bloodless operating field, sterilization of the wound site, minimal swelling and scarring, reduction of surgical time and less postoperative pain to the patient. It should appeal to dental professionals seeking to optimize the procedures they currently perform and expand the number of services they offer.

Aberrations in the root canal anatomy are a commonly occurring phenomenon. A thorough knowledge of the basic root canal anatomy and its variations is necessary for successful completion of the endodontic treatment. The maxillary molars has fascinated researchers and clinicians for a variety of reasons. Endodontically, these are the most misunderstood teeth, and presents a variety of considerations for the treating practitioner. This case report presents the endodontic management of a maxillary first molar with five roots and five canals and another case of maxillary third molar with four canals. The clinical detection of the five canals was made using loupes and confirmed using computed tomography (CT) scanning. This report serves to remind clinicians that such anatomical variations should be taken into account during endodontic treatment of the maxillary molars.