Aim: To evaluate the antimicrobial potential of irreversible hydrocolloid impression material manipulated using chitosan impregnated solution at various time intervals. Setting and Design: Evaluative invivo study design. Materials and Methods: Maxillary impressions made for 20 dentulous volunteers using irreversible hydrocolloid impression material manipulated using distilled water as control and using 1% chitosan impregnated solution as test group using stock metal trays with one-week interval. Bacterial samples were collected using dry sterile cotton swab in the mid-palatal region at the time intervals of 0, 10, 20 minutes. Bacterial swabs were inoculated on nutrient agar media and incubated at 37° C for 24 hours. Bacterial colonies were counted with the aid of colony counter. Statistical Analysis Used: The resultant data was subjected to statistical analysis using repeated measures ANOVA and independent t test. Results: Adding water soluble chitosan to irreversible hydrocolloid impression material resulted in superior antimicrobial activity. With the passage of time there was a significant decrease in the microbial colony count upto 10min (p=0.016). However, the rate of decrease of microbial colony count was statistically insignificant between the samples collected at 10 and 20 min. Conclusion: Incorporation of water soluble chitosan to irreversible hydrocolloid impression material showed significant antimicrobial activity in 10 minutes.

Aim:A study has been undertaken to evaluate the changes in occlusal force dynamics after conventional prosthetic rehabilitation.Materials and Methods:In Phase I, the preprosthetic phase, force distribution of 50% ± 10% on either sides of arch in maximum intercuspation and disclusion time (DT) <1 s during mandibular excursions was attained in all patients using Tekscan before starting prosthetic treatment. Conventional procedures to replace missing tooth by fixed dental prosthesis were carried out. Occlusal corrections were performed using articulating paper to the satisfaction of operator and patient. In Phase II, postprosthetic phase, 1 week after cementation of the fixed partial dentures, the occlusal force dynamics were rerecorded and evaluated using Tekscan. Any corrections required were done to restore the equilibrium. Occlusal perception of patient before and after equilibration was recorded by means of a standard questionnaire both in pre- and postprosthetic phase. Twenty patients requiring replacement of a single posterior missing tooth were selected. The obtained values were statistically analyzed using Student's t-test.Results:Subsequent to rehabilitation, the right–left balance of occlusal load was lost and DT was significantly increased. However, the subjective evaluation revealed no significant decline in occlusal comfort.Conclusion:Null hypothesis was rejected. Operator's assessment of articulating paper marks and patient's occlusal perception is not reliable in restoring occlusal equilibrium.

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Aim: Use of silicone fit-checking material during cementation of fixed restoration has shown to leave residual silicone film after peeling off of fit checker (FC). This residual film reduced bond strength of cement to the inner surface of restoration. Silicone residue effect on tooth surface needs to be studied. The aim of this study was to evaluate the effect of residual silicone film on shear bond strength (SBS) of glass ionomer cement (GIC) to dentin surface and the efficacy of different surface treatments (STs) on dentin in the removal of silicone residue. Materials and Methods: Fifty freshly extracted human molars were individually mounted on acrylic blocks and occlusal surfaces were ground flat until dentine surface was exposed. Specimens were divided into five groups as follows: Group I: without application of FC ( n = 10) as control group; Group II: without any ST after peeling off FC ( n = 10); Group III: ST using wet pumice after peeling off FC ( n = 10); Group IV: ST with 37% phosphoric acid after peeling off FC ( n = 10); and Group V: ST with 10% polyacrylic acid after peeling off FC ( n = 10). GIC was placed on the dentinal surface using polyvinyl mold and subjected to SBS test using universal testing machine. The debonded specimens were observed under stereomicroscope for the mode of failure. Selected debonded dentinal surfaces from each group were examined under scanning electron microscope. One-way analysis of variance and Tukey's test. Results: Group II (1.083 MPa) showed significantly lower SBS. Among the STs, Group III (2.047 MPa) was comparable to the control group whereas Group IV (1.376 MPa) and Group V (1.63 MPa) were significantly lower. There was no significant association between failures and groups at P = 0.257. Conclusion: The residue of silicone was demonstrable on dentin surface after peeling off FC and caused a significant reduction in SBS between GIC and dentin. ST with wet pumice is found to be beneficial in removing silicone residue and improving SBS, followed by phosphoric acid and polyacrylic acid.