A study on the wear of enamel caused by monolithic zirconia and the subsequent phase transformation compared to two other ceramic systems.

PURPOSE: The purpose of this in vitro research project was to evaluate and compare the wear behavior of human tooth enamel opposing monolithic zirconia and other different ceramic restorative materials and also to observe the tetragonal to monoclinic phase transformation in zirconia-based ceramics that may occur while simulating wear occurring at room temperature in a wet environment. MATERIALS AND METHODS: A total of sixty samples were prepared for this study. Fifteen discs of glazed zirconia, 15 discs of polished zirconia without glaze, 15 discs of metal ceramic, and 15 discs of lithium disilicate were fabricated. Sixty extracted premolars were collected and randomly divided into four groups of 15 each. The discs and extracted human premolars were placed onto holders on a two-body wear machine under a constant load of 5 kg to simulate the oral wear cycle. A diffractometer was used to analyze phase transformation. One-way analysis of variance and Tukey's post hoc tests was used. RESULTS: The mean loss of height of tooth samples and its standard deviation for Group I (monolithic zirconia with glaze), Group II (mechanically polished monolithic zirconia without glaze), Group III (porcelain fused to metal), and Group IV (glazed monolithic lithium disilicate) was obtained as 0.2716 ± 0.1409, 0.1240 ± 0.0625, 0.1567 ± 0.0996, and 0.2377 ± 0.1350, respectively. The highest mean loss in height was observed in Group I and the least was observed in Group II. CONCLUSION: Mechanically polished zirconia showed the least amount of enamel wear followed by porcelain fused to metal and glazed monolithic lithium disilicate, whereas glazed monolithic zirconia showed the highest enamel wear.

Is advertising by dental professionals having a negative impact on consumers?: the perspectives of Indian consumers.

Advertising by dentists is a controversial issue. Many feel that advertising is necessary for creating dental awareness, whereas, many others feel that it should be banned to keep intact the ethical aspect of the profession, which aims at serving the community. This study explores consumers' ideas about advertising. A total of 562 respondents from various parts of India participated in this study. The response rate was 46.83%. The data were analyzed by applying the chi-square test of association and the Z test of difference between two proportions at 5% and 1% level of significance (i.e., p<.05 and p<.01).

Postural Assessment of Students Evaluating the Need of Ergonomic Seat and Magnification in Dentistry.

Dental students using conventional chairs need immediate change in their posture. Implementing an ergonomic posture is necessary as they are at high risk for developing musculoskeletal disorders. This study recommends the use of an ergonomic seat and magnification system to enhance the visibility and the posture of an operator. The aim of this study is to make a foray into the hazards caused by inappropriate posture of dental students while working. It also aims at creating a cognizance about the related health implications among the dental fraternity at large, and to understand the significance of adopting an ergonomic posture since the beginning of the professional course. In the present study, postures have been assessed by using rapid upper limb assessment (RULA). This method uses diagrams of body postures and three scoring tables to evaluate ones exposure to risk factors. Ninety students from II BDS (preclinical students in the second year of dental school) were assessed in three groups using three different seats with and without magnification system. The results recorded significantly higher RULA scores for the conventional seats without using the magnification system compared to the SSC (Salli Saddle Chair-an ergonomic seat) with the use of magnification system. A poor ergonomic posture can make the dental students get habituated to the wrong working style which might lead to MSDs (Musculoskeletal diseases). It is advisable to acclimatize to good habits at the inception of the course, to prevent MSDs later in life.

Three-Dimensional Analysis of the Anatomical Characteristics and Dimensions of the Nasopalatine Canal Using Cone Beam Computed Tomography.

AIM: Placement of implants in the maxillary anterior region needs to be preceded by careful analysis of the area as in addition to the functional aspect the esthetic outcome is of prime importance. This descriptive study evaluated anatomical characteristics and dimensions of the nasopalatine canal (NC) from coronal, sagittal and axial aspects using cone beam computed tomography (CBCT) giving it a three dimensional analytical approach. Also the dimensions of the corresponding buccal bone plate (BBP) of the alveolar process were evaluated. Additionally, the influence of age and gender on these characteristics was also analyzed. METHODS: A total of 81-CBCT scans of patients with one or no upper central incisors present were selected. Sagittal slices were used for measurements of the NC and BBP and to evaluate shape of the NC. Coronal slices were used to assess NC shape and axial slices to assess number of incisive foramina and foramina of Stenson. RESULTS: The most prevalent canal shape was: cylindrical (48.14 %) in sagittal aspect; Y-type (49.38 %) in coronal aspect; and one incisive foramen with two Stenson's foramina [1-(2-5)] (60.49 %) in axial aspect. Mean NC length was 11.13 ± 3.23 mm; statistically significant differences were detected between genders (p < 0.001). Mean nasopalatine angle was 69.32° ± 7.70. Mean BBP length was 17.12 ± 3.97 mm and mean BBP width was 5.71 ± 1.29 mm, significant differences were detected between genders (p < 0.001). CONCLUSION: The current study demonstrates variability of the NC in terms of anatomical characteristics and dimensions; hence, a thorough CBCT analysis is highly recommended for better surgical outcomes and to reduce the post-operative complications in implant dentistry.