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. Keywords: Heat cure resins, Methyl methacrylacte, Polymethylmethacrylate, Percentage of cohesive, Failure, Shear bond strength. How to cite this article: Rao CS, Reddy SS, Prasad GM, Reddy KS, Rao NV, Naik MS. 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. J Contemp Dent Pract 2012;13(3):394-400. Source of support: Nil Conflict of interest: None declared.     

Exotic and indigenous problem plants species used,by the Bapedi,to treat sexually transmitted infections in Limpopo Province,South Africa

Background

The ethnic usage of exotics and indigenous problem plants is a highly debated topic, as legislative requirements over-shadow their potential medicinal value, particularly to treat sexually transmitted infections (STIs). Limited information exists regarding their medicinal value among the Bapedi.

Objectives

To ascertain the importance of exotics and indigenous problem plants in the treatment of STIs, a major global primary health care challenge.

Methods

A field observation and semi-structured questionnaire focussing on species diversity, types of STIs treated and medicinal preparation as well as application was used to collect data from 34 traditional healers.

Results

Seven exotics and three indigenous problem species were identified. These species were used to treat four STIs; with Catharanthus roseus illustrating its dominance in the treatment of gonorrhoea. Some medicinal species used by Bapedi traditional healers have been validated through scientific research or through their extensive use by various cultures in South Africa and other parts of Africa. To the best of our knowledge Alternanthera pungens, Caesalpinia decapetala, Cinnamomum verum, and Citrullus lanatus are reported for the first time in the treatment of the investigated STIs.

Conclusions

Exotic and indigenous problem species constitute an important component of the STIs treatment protocol. Their utilization by Bapedi cautions against the narrow-minded approach of indiscriminate eradication, as these species can play a significant role in the primary health care needs of socio-economic vulnerable people.     

Clinical Efficacy of Subgingivally Delivered 1.2% Atorvastatin in Chronic Periodontitis: A Randomized Controlled Clinical Trial

Background: Atorvastatin (ATV) is a specific competitive inhibitor of 3‐hydroxy‐2‐methyl‐glutaryl coenzyme A reductase. Recently, statins have shown pleiotropic effects such as anti‐inflammation and bone stimulation. The aim of the present study is to investigate the effectiveness of 1.2% ATV as an adjunct to scaling and root planing (SRP) in the treatment of intrabony defects (IBDs). Methods: Sixty individuals were randomized into two treatment groups: SRP plus 1.2% ATV and SRP plus placebo gel. At baseline and 3, 6, and 9 months, clinical parameters, which included modified sulcus bleeding index, plaque index, probing depth (PD), and clinical attachment level (CAL), were recorded at baseline. Radiologic assessment of IBD fill was done using computer‐aided software at baseline and 6 and 9 months. Results: Mean PD reduction and mean CAL gain were greater in the ATV group than the placebo group at 3, 6, and 9 months. A significantly greater mean percentage of radiographic bone fill was found in the ATV group (35.49% ± 5.50%) compared to the placebo group (1.82% ± 1.32%) after 9 months. Conclusion: ATV as an adjunct to SRP can provide a new direction in the management of IBDs.     

“GIOSAT”: a tool to assess CanMEDS competencies during simulated crises

Purpose

Our objective was to develop and evaluate a Generic Integrated Objective Structured Assessment Tool (GIOSAT) to integrate Medical Expert and intrinsic (non-medical expert) CanMEDS competencies with non-technical skills for crisis simulation.

Methods

An assessment tool was designed and piloted using two pediatric anesthesia scenarios (laryngospasm and hyperkalemia). Following revision of the tool, we used previously recorded videos of anesthesia residents (n = 50) who managed one of two intraoperative advanced cardiac life support (ACLS) scenarios (ventricular tachycardia or ventricular fibrillation). Four independent trained raters, blinded to the residents’ level of training, analyzed the video recordings using the GIOSAT scale. Inter-rater reliability was calculated using intraclass correlations (ICCs) for single raters (single measure) and the average of the four raters (average measure), and construct validity was investigated by correlating GIOSAT scores with postgraduate year of residency (PGY).

Results

Total GIOSAT scores for the ACLS scenarios had single measure ICCs of 0.62 and average measure ICCs of 0.85. Inter-rater reliability was substantial for both Medical Expert and intrinsic competencies (single measure ICCs 0.69 and 0.62, respectively; average measure ICCs 0.90 and 0.82, respectively). We found significant correlations between PGY level and total GIOSAT score (r = 0.36; P = 0.011) and between PGY level and Medical Expert competencies (r = 0.42; P = 0.003); however, correlations were not found between PGY level and intrinsic CanMEDS competencies (r = 0.24; P = 0.09).

Conclusion

Inter-rater reliability of the total GIOSAT scores using four trained raters was substantial. Significant correlation between PGY and (i) total GIOSAT score and (ii) Medical Expert competencies supports construct validity. Evidence of validity was not obtained for intrinsic CanMEDS competencies.     

Evaluation of treatment of calcaneal fractures with a modified approach in a peripheral setting: a cost-effective model

Background

We present the results of open reduction and internal fixation of intra-articular calcaneal fractures with Kirschner wires with some modifications.

Material and methods

A longitudinal study was done on 37 patients who had fallen from certain heights; the study subjects were predominantly construction workers. Forty-seven fractures of the study subjects were treated using a modified approach that includes incision and some tips in operative technique. Details of modification and their evaluation on the basis of restoration of heel shape with special attention to the lateral wall, radiological assessment of Bohler’s angle, varus and valgus movement of the heel, pain while walking, patient satisfaction assessment upon return to pre-injury work are elaborated in this paper. Duration of study was from January 2000 to May 2011.

Results

The fractures healed well with good radiological and functional outcomes, and patients returned to pre-injury work status in 4–6 months.

Conclusion

The need to change to the Kocher approach for the treatment of calcaneal fracture with right-angled incision and elevation of the lateral flap is not necessary if the surgical tips showed in this paper are followed meticulously to achieve a good soft tissue outcome initially and, eventually, a good bony radiological and functional outcome. As implants used are very cheap and affordable to workers of low socioeconomic status, the authors have developed this method and presently believe that this method is best for all classes of patients with the said problem.     

Bethlem myopathy: An autosomal dominant myopathy with flexion contractures,keloids, and follicular hyperkeratosis

Bethlem myopathy and Ullrich congenital muscular dystrophy form a spectrum of collagenopathies caused by genetic mutations encoding for any of the three subunits of collagen VI. Bethlem phenotype is relatively benign and is characterized by proximal dominant myopathy, keloids, contractures, distal hyperextensibility, and follicular hyperkeratosis. Three patients from a single family were diagnosed to have Bethlem myopathy based on European Neuromuscular Centre Bethlem Consortium criteria. Affected father and his both sons had slowly progressive proximal dominant weakness and recurrent falls from the first decade. Both children aged 18 and 20 years were ambulant at presentation. All had flexion contractures, keloids, and follicular hyperkeratosis without muscle hypertrophy. Creatinine kinase was mildly elevated and electromyography revealed myopathic features. Muscle imaging revealed severe involvement of glutei and vasti with “central shadow” in rectus femoris. Muscle biopsy in the father showed dystrophic changes with normal immmunostaining for collagen VI, sarcoglycans, and dysferlin.Key Words: Bethlem myopathy, collagen VI, contractures, immunohistochemistry, keloids