A comparative evaluation of the dimensional accuracy of heat polymerised PMMA denture base cured by different curing cycles and clamped by R S technique and conventional method - An In-vitro study.

BACKGROUND: The aim of this study is to evaluate the dimensional accuracy of heat polymerized PMMA denture base clamped by the conventional method and by R.S technique and cured by a different curing cycle. MATERIALS & METHODS: In this study, a total of 40 standardized maxillary record bases were fabricated with seven reference points: Point A - Incisive papilla, Point B & C - Canine region on either side, Point E & G - Midpoint of tuberosities on either side, Point F- Midpoint of the line joining the two tuberosities, Point D- Midpoint between the line joining A and F. Group A: Ten maxillary record bases were fabricated by conventional clamping method and cured by long curing cycle. Group A1: Ten maxillary record bases were fabricated by R.S tension clamping method and cured by long curing cycle. Group B: Ten maxillary record bases were fabricated by conventional clamping method and cured by short curing cycle. Group B1: Ten maxillary record bases were fabricated by R.S tension clamping method and cured by short curing cycle. The distances between the reference points i.e. A-B, A-C, A-D, D-F, B-E, C-G, E-F, F-G, B-D, D-G, CD, D-E of all three thermoplastic denture base plates were measured and recorded with the help of a travelling microscope and were used for comparison with the measured and recorded readings of processed acrylic denture bases. The data obtained was analyzed by using the One Way Analysis of Variance. RESULTS: The overall results of the in vitro study indicate that among all the PMMA bases cured by the two clamping systems and the different curing cycle, group A` was the most dimensionally stable, followed by control group A, then followed by B` and B was most unstable. CONCLUSION: The study concluded that the denture bases fabricated by the R.S Technique using the long curing cycle would produce the most dimensionally stable PMMA denture bases. How to cite the article: Babu MR, Rao CS, Ahmed ST, Bharat JS, Rao NV, Vinod V. A comparative evaluation of the dimensional accuracy of heat polymerised PMMA denture base cured by different curing cycles and clamped by R S technique and conventional method - An In-vitro study. J Int Oral Health 2014;6(2):68-75.

DiaTreat: a new method of communication for better diagnosis and treatment of dental problems.

AIM: The aim of this article is to present a simple method of communication between two oral health professionals so that the problem can be conveyed easily and treatment options obtained equally easily and quickly, using current electronic communication technologies. BACKGROUND: Treatment of dental problems involves a thorough understanding of the underlying dental and medical conditions. The arena of dentistry being ever changing, with new specialties arising each year, it has become virtually impossible for an average dentist to keep track of all the treatment modalities available for various problems at a given time. It is the duty of a dentist, however, to treat his patients to the best of his ability. Professional ethics bind the other health professionals to render their opinion to the dentist so that the patient will ultimately get the best possible treatment. Method of communication is the only problem remaining in the path to achieving a total oral health care. TECHNIQUE: DiaTreat is a unique method of clinical charting by which a dentist can incorporate all the ailments affecting his patient, and by withholding the patients name and address, can communicate with any of his colleagues for their opinion on the best treatment option for his patient. CONCLUSION: It is a new and innovative method of communication between a dentist and specialist. Even though it has some shortcomings of its own, on a wider range, the advantages far outweigh the drawbacks of the system. CLINICAL AND ACADEMIC SIGNIFICANCE: This can also be used by educational institutes for easy communication during interdisciplinary exchanges. Improvements need to be made yet to incorporate all the ailments known in dental discipline and make communication a comprehensive one.

A study to evaluate and compare the shear bond strength of resilient liners with heat cure denture base resins, with and without the effect of saliva: an in vitro study.

AIM: To evaluate and compare the shear bond strength of resilient liners with heat cure denture base resins in the presence or absence of saliva. MATERIALS AND METHODS: Two commercially available heat polymerized acrylics and three commercially available denture liners were immersed in artificial saliva for 7 days and 14 days, respectively. A total of 180 (Acralyn-H, No.90 and Lucitone - 199, No.90) specimens were prepared. Total of 90 overlapping joint specimens were prepared, 45 of them using Acralyn H (AGroup) and rest 45 using Lucitone-199 (L-Group). The specimens were tested for flexural strength with a 3-point bending test on an Instron universal testing machine. The results were analyzed with a one-way analysis of variance (ANOVA). RESULTS: The mean difference in shear bond strength (SBS) at different time intervals was found to be statistically significant (p < 0.001). Lucitone-199 recorded a significantly higher mean SBS compared to Acralyn H (p < 0.001). Further, significant differences between GC and Densply, GC and Aswin liners, and between Dentsply and Aswin were noted (p < 0.001). Difference between baseline and 7 days time interval, as well as, between baseline and 14 days time interval with respect to the mean SBS of these materials were significant (p < 0.001). Also, the mean difference in SBS between 7 days time interval and 14 days time interval was statistically significant (p < 0.001). Among the three different liners, GC yielded a higher mean SBS compared to Aswin and Dentsply at all the three time intervals. The mean SBS recorded in Dentsply and Aswin was almost same at 14 days time interval, but at baseline and 7 days, it was higher in Aswin compared to Dentsply. CONCLUSION: Lucitone-199 recorded a higher mean SBS compared to Acralyn H. As the time interval increases, the mean SBS recorded in both the denture base materials decrease. Among the three different liners, GC yields a higher mean SBS compared to Aswin and Dentsply at all the three time intervals. CLINICAL SIGNIFICANCE: The most common reason for failures of resilient linings in removable dentures is the separation of these linings from the denture base. Therefore, poor adhesive bond properties are one of the serious defects of the material in clinical practice.

A starter's guide to preclinical teeth arrangement: simplified clinometer.

UNLABELLED: Arrangement of artificial teeth in a bilaterally symmetrical fashion with proper inclinations of teeth had been a challenging task for beginners. A variety of tools and guiding equipment have been developed to help students to learn teeth arrangement. Unfortunately, those tools were either costly or unsuitable for use with mean value articulators. This article attempts to introduce a simplified clinometer which can be attached to mean value articulator and can be used as a guide to arrange teeth in a bilaterally symmetrical manner by the undergraduates in both clinical and preclinical set-up. CLINICAL SIGNIFICANCE: Training of the future dentists in sound esthetic principles in a preclinical environment, using this device, will increase the final clinical efficacy of their work. AIM: The aim of this article is to provide a simple but effective device to undergraduate students to help them learn teeth arrangement easily and systematically.

A comparative evaluation of the dimensional accuracy of heat polymerized acrylic resin denture base clamped by the conventional method and by new-press technique and cured by long curing cycle: an in vitro study.

AIM: The aim of this study is to evaluate the dimensional accuracy of heat polymerized acrylic resin denture base clamped by the conventional method and by new-press technique and cured by long curing cycle. MATERIALS AND METHODS: In this study, a total of 60 standardized maxillary record bases were fabricated with seven reference points as follows: Point A: Incisive papilla, Point B and C: Canine region on either side Point E and G: Midpoint of tuberosities on either side Point F: Midpoint of the line joining the two tuberosities Point D: Midpoint between the line joining A and F. GROUP A: Ten maxillary record bases were fabricated by conventional clamping method and cured by long curing cycle. GROUP A': Ten maxillary record bases were fabricated by New Press or RS tension clamping method and cured by long curing cycle. The distances between the reference points, i.e. A-B, A-C, A-D, D-F, B-E, C-G, E-F, F-G, B-D, D-G, C-D, D-E of all three thermoplastic denture base plates were measured and recorded with the help of travelling microscope and were used for comparison with the measured and recorded readings of processed acrylic denture bases. The data obtained was analyzed by using the one-way analysis of variance and HSD Multiple Comparison Test. RESULTS: The overall results of the study indicate that among all the denture bases cured by the two clamping systems and the long curing cycle, group A' were the most dimensionally stable, followed by control group A. CONCLUSION: The study concluded that the denture bases fabricated by the New Press method using the long curing cycle would produce the most dimensionally stable denture bases.

Effect of trichloromethane on the bond strengths between acrylic teeth and different heat-cured denture bases: a comparative study.

AIM: This study is to evaluate the role of 1:1 v/v 30% trichloromethane and monomer solvent in enhancing the durability of bonding between cross-linked acrylic teeth and different heatcured denture bases with or without mechanical preparations made on ridge lap portion of the artificial teeth. MATERIALS AND METHODS: Two high impact denture base resin materials (Trevalon HI, DeTrey, UK, and DPI Tuff, Mumbai) and one nonhigh impact denture base resin material (DPI Quick Set, Mumbai) were selected to form three groups. Each group contains 30 specimens prepared by five different methods. A mixture of 30% trichloromethane and monomer, mixed in the ratio of 1:1 and applied for 1 minute on the ridge lap area of experimental specimens of methods--B, C, D and E (Specimens of method--A being control group, where no alterations were made at the ridge lap portion of acrylic teeth) before curing. Hounsfield universal testing machine is employed to evaluate the comparative bond strengths. RESULTS: No significant difference was seen in bond strengths between specimens of experimental methods in all groups. When each group was assessed separately method B specimens in group 1 (739.2 N), group 2 (758 N) and method D specimens in group 3 (729 N) showed highest mean bond strengths. Control group specimens showed the least bond strength (400-460 N) in all groups with more adhesive failures. CONCLUSION: Ridge lap portion of the specimens treated with chemical solvent as in method B showed increased bond strength in groups 1 and 2. Hence, this is a preferred method. CLINICAL SIGNIFICANCE: Evaluation of effect of different chemical and mechanical preparations at the ridge lap areas of acrylic teeth before acrylization helps the clinician and technician to overcome the problem of debonding of teeth from denture bases and in turn provides better quality prosthesis to the patient.