Recently, polyetheretherketone (PEEK) has been introduced to the dental market as a high-performance and chemically inert biomaterial. This study aimed to compare the wear resistance, abrasiveness, color stability, and displacement resistance of zirconia and PEEK milled crowns. An ideal tooth preparation of a first maxillary molar was done and scanned by an intraoral scanner to make a digital model. Then, the prosthetic crown was digitally designed on the CAD software, and the STL file was milled in zirconia (CaroZiir S, Carol Zircolite Pvt. Ltd., Gujarat, India) and PEEK (BioHpp, Bredent GmbH, Senden, Germany) crowns using five-axis CNC milling machines. The wear resistance, color stability, and displacement resistance of the milled monolithic zirconia with unfilled PEEK crowns using a chewing simulator with thermocyclic aging (120,000 cycles) were compared. The antagonist wear, material wear, color stability, and displacement were evaluated and compared among the groups using the Wilcoxon–Mann–Whitney U-test. Zirconia was shown to be three times more abrasive than PEEK (p value < 0.05). Zirconia had twice the wear resistance of PEEK (p value < 0.05). Zirconia was more color stable than PEEK (p value < 0.05). PEEK had more displacement resistance than zirconia (p value < 0.05). PEEK offers minimal abrasion, better stress modulation through plastic deformation, and good color stability, which make it a promising alternative to zirconia crown.

The radiographic examination is one of the principal diagnostic methods used in all fields of medical services and contributes to the promotion of the health. Accordingly, a certain amount of radiation is inevitably delivered to patients during normal radiographic procedures. Repeated radiation doses utilized in dental treatment might be harmful to the patients and thus a thorough knowledge on radiation protection protocols are mandatory for dental clinicians. The aim of this study was to investigate the knowledge, awareness and practice of general dentists practicing in the Chennai regarding radiation prevention protocols undertaken in their area of work. The study was a questionnaire based cross-sectional study. A total of 200 dentists were contacted to participate in the study. The target population entailed were general dentists practicing in Chennai. A Pretested questionnaire was mailed to the respondents following informed consent. The data were extracted from the responses and analyzed. The total response rate recovered was 75 % and the respondents comprised of 54 males & 96 females respectively. Only 49% of the general dentists followed the position & distance rule for radiographic procedures appropriately. The results showed that the knowledge, awareness of the general dentists regarding radiation prevention protocols in Chennai were satisfactory. However, the practice regarding radiation protection protocols were inadequate. To ensure the implementation of radiation prevention protocols, strict protocols must be followed by the licensing and monitoring authorities about the use of the equipment emitting radiation and rigorous health education programs should be initiated to sensitize the clinicians.