Evaluation of the marginal microleakage of CAD-CAM compared with conventional interim crowns luted with different types of cement: An in-vitro study.

BACKGROUND: Temporary stage in crowns and bridgework plays an important role in the success and failure of the final restorations. Lack of marginal seal of the temporary restorations can lead to further complications. Recently, digital dentistry has been improved in terms of marginal integrity. AIMS: The aim of this study was to evaluate and compare the marginal leakage between CAD/CAM and conventionally made Polymethyl methacrylate (PMMA) interim crowns cemented with different temporary luting cements. MATERIALS AND METHODS: Sixty resin dies of a maxillary right first premolar were prepared according to the protocol of the tooth preparation for all-ceramic crown. Interim crowns were then fabricated and assigned to two main groups according to the fabrication technique (CAD/CAM technique and conventional technique). Furthermore, the samples were sub-grouped (n = 10) according to the type of the luting cements: Zinc oxide eugenol (RelyX temp E), Zinc oxide non-eugenol (RelyX temp NE), and Zinc polycarboxylate cement (pentron). The specimens were then subjected to thermocycling at 5°C and 55°CC for 30 sec and transfer time of 15 seconds for 1500 cycles. After that, the specimens were immersed in a 2% methylene blue solution for 24 hours. The cemented specimens were sectioned buccolingually and the amount of marginal leakage was evaluated under digital microscope at magnification 50x. The scores of dye penetration were recorded and analyzed using one-way ANOVA at P < 0.05 for all tests. RESULTS: For the fabrication technique, CAD/CAM-made interim crowns had significantly better performance in terms of lower microleakage in comparison to conventionally built interim crowns (P < 0.001). Overall, Zinc Oxide non-eugenol also showed significantly least microleakage as a luting cement then Zinc Oxide Eugenol and the most microleakage was found with Zinc Polycarboxylate regardless of the fabrication method. CONCLUSION: Interim crowns fabricated by CAD-CAM system are better suited for temporization. Zinc-oxide non-eugenol cements showed the least amount of microleakage in both types of crown.

Evaluation of the causes of failure of root canal treatment among patients in the City of Al-Kharj, Saudi Arabia.

BACKGROUND: Endodontic treatment failure is one of the most common problems encountered in dentistry. AIMS: This study aimed to evaluate the causes of failure of endodontic treatment among patients in the Saudi Arabian city of Al-Kharj. SUBJECTS AND METHODS: A total of 250 patients of both genders were involved in the study. Criteria confirming the failure of the endodontic treatment were pain, tenderness on pressure, periapical radiolucency, and sinus tract. Patients were selected by convenience sampling methods. A diagnostic chart was prepared to complete the investigation in three different hospitals, during a six-month period (October 2018 - March 2019). The results were analyzed statistically using Chi-square test and use of simple arithmetical methods to determine percentage and frequencies. RESULTS: The main cause for endodontic failure was poor quality adjunctive treatment. 147 out of 179 male patients and 53 out of 71 female patients received poor quality treatment. There was a statistically significant difference between gender versus adjunctive treatment (P = 0.009) and between hospital versus adjunctive treatment (P = 0.005), and quality of adjunctive treatment between private hospital as compared to government hospital which was also statistically significant (P = 0.008). In quadrant wise distribution, first molars were the most commonly involved teeth. Inadequate filling of the root canal was (36.8%), missed canals (14.4), over-extension root canal fillings (12.8%), perforations (9.6%), instrumentation related (8.8%), and endodontic access preparation related (2.4%) in the decreasing order of frequency were seen as the most common causes of failure of endodontic treatment. CONCLUSION: First molars were the most commonly affected tooth in the failure of endodontic treatment. Poor adjunctive treatment and inadequate filling of the root canals were the most common causes of endodontic failure, more commonly seen in male than female patients and in private clinics/hospitals than government hospitals.