In vitro propagation and analysis of mixotrophic potential to improve survival rate of Dolichandra unguis-cati under ex vitro conditions.

An efficient and reproducible protocol for in vitro propagation of Dolichandra unguis-cati has been established for the first time from nodal segments. In order to enhance survival rate under ex vitro conditions, photosynthetic potential of in vitro grown plantlets was also studied through JIP test based analysis of polyphasic OJIP chlorophyll a fluorescence OJIP transients, density of active reaction centers, light harvesting efficiency, electron transfer rate, dissipation energy, maximum quantum yield of primary PSII photochemistry and photosynthetic performance index. The best morphogenetic in term of explants response (92.2 %), shoot number (3.43 ± 0.07) and shoot length (4.7 ± 0.31 cm) was obtained on Murashige and Skoog medium supplemented with 0.5 mg l-1 BAP and 1.0 mg l-1 TDZ. The shoots exhibited high frequency rhizogenesis on half strength medium augmented with 2.0 mg l-1 IAA. In vitro plantlets developed highest rate of photosynthesis on day 18 after the initiation of rhizogenesis. High survival rate (96.16%) under ex vitro conditions was observed when in vitro plantlets having high photosynthetic efficiency (Fv/Fm > 0.75) were subjected to hardening and acclimatization process. Plantlets with reduced photosynthetic performance exhibited low survival rate under natural conditions. The developed in vitro protocol will be useful for genetic improvement and multiplication of D. unguis-cati. The results of this study also show that photosynthetic screening of in vitro developed plantlets is highly essential after the rhizogenesis process to achieve higher survival rate under field conditions.

Comparative Evaluation of Remineralizing Effect of Novamin and Tricalcium Phosphate on Artificial Caries: An in vitro Study.

AIM: The aim of the present study was to compare the remineralizing efficacy of novamin and tricalcium phosphate (TCP). MATERIALS AND METHODS: Nail varnish was coated to a total of 30 sound human premolars except for 5 mm × 5 mm window. Baseline microhardness was measured for all test samples. Artificial carious lesions were created for all teeth by subjecting them to demineralization process. Then microhardness of demineralized lesion was measured. Later artificial caries teeth were equally divided into two groups to treat with remineralization solution for 10 days; group I: novamin and group II: TCP. After 10 days of pH cycling, microhardness was measured. The data were statistically analyzed using Statistical Package for the Social Sciences (SPSS) statistical software from Chicago SPSS Inc., version 21 and using analysis of variance (ANOVA) post hoc multiple comparisons test for intergroup and significant difference at p < 0.05. RESULTS: In the present study, group I indicated a higher value for remineralization compared with group II (p < 0.05). CONCLUSION: The present study showed that both novamin and TCP were effective in remineralizing the carious lesions. CLINICAL SIGNIFICANCE: This study evaluates the remineralizing potential of novamin and TCP on initial carious lesions.

Comparative Evaluation of Fracture Resistance of Different Post Systems.

AIM: The study was done to evaluate the fracture resistance of carbon, glass fiber, and zirconia posts. MATERIALS AND METHODS: Forty-five human premolars indicated for orthodontic extraction were subjected to root canal treatment and obturated with gutta-percha. All the teeth were decoronated and mounted in acrylic block. Then, teeth were equally divided into three groups: (a) carbon, (b) glass fiber, and (c) zirconia post group. Post space was prepared and particular post was cemented in post space. Core buildup was made with composite. A compressive load was applied using universal testing machine and fracture force was measured in MPa. The data were tabulated, and statistical evaluation was done using statistical software IBM SPSS Statistics for Windows, version 21.0., IBM Corp., Armonk, NY, USA, using one-way analysis of variance for analysis of difference and Bonferroni post hoc test. RESULTS: Zirconia endodontic post had good fracture resistance (489.2 MPa) when compared with carbon (258.4 MPa) and glass fiber-reinforced post (348.7 MPa). Fracture resistance was statistically significant between test groups P>0.001. CONCLUSION: The present study concluded that zirconia had good fracture resistance compared to glass fiber and carbon posts.

A Comparative Evaluation of the Retention of Tooth Coloured and Stainless Steel Endodontic Posts: An In-vitro Study.

AIMS: This in vitro study evaluated: a) the retention of stainless steel posts of 1.5 mm diameter which were cemented with Zinc Phosphate cement versus Glass fiber posts with 1.1 mm, 1.3 mm and 1.5 mm diameters which were cemented with resin cement and b) the effect of change in diameter on the retention of Glass fiber posts with 1.1 mm, 1.3 mm and 1.5 mm diameters. MATERIALS AND METHODS: Sixty extracted mandibular premolar teeth were endodontically treated and randomly assigned to four groups of fifteen teeth each. In Groups I, II and III glass fibre posts with diameters 1.1 mm, 1.3 mm and 1.5 mm were cemented by using resin cement. In Group IV, stainless steel posts with diameter 1.5 mm were cemented by using zinc phosphate cement. The specimens were tested for tensile loading at a cross head speed of 2.0 mm/min, on a universal testing machine. STATISTICAL ANALYSIS USED: One way analysis of variance and Tukey's (post-hoc) test. RESULTS: Mean tensile strength from highest to lowest was in the order of Group IV, Group II, Group III, Group I. Statistically significant differences were observed between the mean tensile strengths between Groups I and II, Groups I and III, Groups I and IV, Groups II and IV, Groups III and IV, while non significant differences were observed between Groups II and III. CONCLUSION: Stainless steel posts were more retentive than glass fibre posts. Glass fibre posts with 1.3 mm or 1.5 mm diameters provided significantly greater retention as compared to 1.1 mm diameter posts.

Protocol for Removal of Third Molar Root Tips from the Inferior Alveolar Canal-Crossing the line.

INTRODUCTION: The safe removal of third molars involved with the inferior alveolar canal (IAC) has been an area of concern since long. Many times we hesitate for the removal of third molars, fearing injury to the inferior alveolar nerve. MATERIALS AND METHODS: The authors here describe a simple technique which can be used to remove third molars showing evidence of proximity to IAC on presurgical radiographic evaluation, as well as those root tips which, during removal, accidentally enter the IAC space. CONCLUSION: A step-by-step protocol is presented along with necessary precautions during the operative procedure.