Effect of acidic environment on color and translucency of different indirect restorative materials.

PURPOSE: The aim of the current study was to evaluate the effect of simulated gastric acid on the color and translucency of different indirect restorative materials. MATERIALS AND METHODS: A total of 36 disc-shaped samples were cut by using an isomet saw and divided into four equal groups (n = 9) according to the material type: Group Z: translucent zirconia (Ceramill® Zolid ht.+ preshade, Amann Girrbach, Koblach, Austria); Group E: lithium disilicate (IPS e.max CAD, Ivoclar Vivadent AG, Schaan, Liechtenstein); Group C: resin nanoceramic (Cerasmart, GC, Tokyo, Japan); Group P: polyether ether ketone (PEEK) (Bettin Zirconia Dentale Italy) veneered with indirect high impact polymer composite (HIPC) (breCAM HIPC, Bredent GmbH & Co. KG, Germany). The samples were immersed in simulated gastric acid (HCl, pH 1.2) for 96 hours at 37 °C in an incubator. The color change (ΔE00) and translucency (RTP00) were measured every 9.6 hours (one-year clinical simulation) of immersion in simulated gastric acid. RESULTS: For color change (∆E00) and translucency (RTP00) among the tested materials, there was a highly statistically significant difference (P < 0.001) after every year of follow-up. The color change in both Z and G groups was the lowest after 1 year of acid immersion, followed by that in group H, and the highest change in color was recorded in group P. CONCLUSION: High translucent zirconia is recommended in patients who are concerned about esthetic, especially with acidic oral environment.

Prevalence of malocclusion, its association with occlusal interferences and temporomandibular disorders among the Saudi sub-population.

AIMS: This Study was conducted to determine the incidence of malocclusion, occlusal interferences, temporomandibular Disorder (TMD) among the Saudi population and to evaluate the possible existence of an association between malocclusion, occlusal interferences and TMD. METHODS: 250 patients attending dental clinics in Abha city, Saudi Arabia for treatment was clinically examined for the degree of malocclusion. Patients were further evaluated for the presence of occlusal interferences and TMD. Data was evaluated by person's correlation and logistic regression to evaluate the association between malocclusion, occlusal interference and TMD. RESULTS: The results of the study indicate 42.8% of the evaluated subjects had a definitive degree of malocclusion. Among the occlusal interference observed, balancing side interferences were high (47.6%), followed by protrusive interferences (41.2%). The prevalence of TMD among the evaluated subjects was 41.6%, with mandibular deviation and joint sounds were most prevalent. Statistical Analysis (Pearson's correlation) showed the statistically significant correlation between malocclusion and centric slide (p-0.030), posterior missing teeth (p-000). The statistically significant correlation was observed between TMD and balanced side interferences (p-0.000), slide RCP-ICP (p-0.001), reduced occlusal contacts (0.033). Logistic regression analysis showed the strong association of TMD with anterior open bite, increased maxillary overjet, balanced side interferences, and centric slide. CONCLUSION: The prevailing malocclusion and TMD among studied population is significantly higher. The preventive dental treatment and community dental education need to be more emphasized.