Monolith Dental Bridge by Soft Machining of Dried Ceramic Dough

All-ceramic fixed restorations are gaining popularity because of increased esthetic consciousness in the younger population. Monolith ceramic crowns and bridges are preferred to withstand masticatory loads where the availability of occlusal height is limited. Machining green blanks of ceramic with organic binders have been studied to reduce loss of final strength, cost, and wastage associated with milling partial sintered and sintered blanks. Notches on the surface/edge associated with green milling will disappear after sintering in contrast to sintered state machining where diamond polishing is essential. In this study, we explored a novel ceramic dough process to form a green body of alumina or 3 Mol% yttria-stabilized zirconium oxide (YSZ), and computer numerical control (CNC) machining was performed on the dried dough. Micro Computer Tomography analysis of the bridges after sintering revealed a negligible void volume, 0.06–0.08% of the total volume, with randomly dispersed voids. Precision analysis of the sintered bridges with respect to the reference file resulted in a deviation range of +0.56 to −0.79 mm, with negligible deviation on the cementation surface. The green machined surface had a roughness profile of 1.2–1.7 μm after machining and 2.2–2.4 μm after sintering, as revealed by 3D profilometry.

The Role of Using Motorized Diamond Burr Polisher Instrument in Minimizing the Recurrent Rate of Pterygium Excision

To compare the effects of using motorized diamond burr polisher in pterygium excision versus manual polishing of the corneoscleral bed in reducing the recurrent rate. A prospective, comparative and interventional study of 90 consecutive patients with different grads of primary pterygium, who underwent pterygium excision at Shahid Aso teaching eye hospital in Sulaimani city, between August 2018 till September 2019, which was performed by single surgeon. In group A (45) eyes polishing of the corneoscleral bed done using motorized diamond polishing burr, and in group B (45) eyes using manual crescent blade for polishing. Recurrent rate was evaluated after about (8±2) months postoperatively. Ethical consideration of the risks and the benefits of the procedure was observed for each individual patient. A 90 patients with the mean age of group A (48.84±12.7) years and group B (49.67±12.3) years, complained of different grads of primary pterygium, group A had 31(68.9%) male and 14(31.1%) female, while group B had 22(48.9%) male and 23(51.1%) female. Each individual factors like age, gender, visual acuity, BCVA pre and postoperatively, IOP measurement, dryness of the eye and risk factors like smoking and UV exposure affecting the recurrence were assessed. In both groups the main indication for surgery was sign of irritation. The mean surgical time was calculated and the difference between two groups were significant. After follow-up of average six months the outcomes and recurrent rate were checked, recurrent rate was in group A 1(2.2%) while in group B was 6(13.3%) patients. it significantly decreased. Corneal scar happens in only 1(2.2%) case of group A while in 11(24.4%) cases in group B, Corneal scar was statistically significant. In both groups the change of BCVA was significant but the visual change was more significant in group A in compare to group B. Motorized diamond burr is a safe instrument for polishing the cornea during pterygium excision, it is easy to handle, low price, need lesser operative time, its effect on recurrence postoperatively is significant and beside it leaves lesser corneal scar and early visual recovery postoperatively.