Comparative study of Dimensional Accuracy of Three Conventional Denture Base Resins Processed By Conventional Method And Microwave Polmerization.

Statement of Problem: Poor adaptations of acrylic resin denture bases to the supporting tissues markedly decrease denture retention. Several denture base resin and processing techniques have been introduced to the profession, each claiming to produce a more accurate base. Microwave processing techniques has been introduced claims to minimize the dimensional changes. Purpose: The purpose of this study was to compare the dimensional accuracy of three denture base resins processed by conventional water bath method and by use of microwave energy. Material and method: Three Poly (MethylMethacrylate) heat cure resins were selected for this study.These resins were processed by (i) conventional water bath technique for 1.5 hours at 1650F and half hour at 2120F and (ii) microwave energy for 3 mins at 500W. A metal master die representing a maxillary arch with 4mm hole was prepared to evaluate the adaptation of the test resin denture base. A total number of 60 specimens were tested. The measurements of acrylic resin denture base specimens were compared with the measurements of master metal die dimension keeping it as a standard measurement. Results: The resin record bases processed by microwave curing method had slightly better dimensional accuracy than conventionally processed bases. There was no significant difference found in the dimensional accuracy when Resin record bases processed with a specially formulated resin for microwave curing was microwave cured and when conventionally available resins were processed by microwave technique. Conclusion: The resin record bases processed by microwave curing method had slightly better dimensional accuracy than the conventionally processed bases.

Visual outcome and complications of residents learning phacoemulsification.

The increasing popularity of phacoemulsification in our country raises important training issues. We prospectively analyzed the incidence of complications and visual outcomes in the initial 70 phacoemulsifications (70 patients) performed by the first two residents learning phacoemulsification in our training programme. Both were experienced in standard (manual) extracapsular cataract extraction. Postoperative follow up of 6 weeks or longer was available in 59 eyes. The 11 patients (11 eyes) lost to follow up did not have any intra-operative complications. The overall incidence of vitreous loss was 10%, similar to the frequency of this complication (determined retrospectively) in the first 70 standard extracapsular cataract extractions performed by the same residents. Intraocular lenses (IOL) were successfully implanted in 62 eyes, as planned. One IOL dislocated into the vitreous was successfully repositioned. Other complications encountered included superior corneal edema (3 eyes), iris damage inferiorly (7 eyes) and clinical cystoid macular edema (5 eyes). A best corrected visual acuity of 6/12 or better was obtained in 56 (94.8%) of the 59 eyes available for the six week follow up. In the eyes with vitreous loss, 6 out of 7 had visual acuity better than 6/12. No nuclei were lost into the vitreous. The rate of surgical complications for residents learning phacoemulsification in a supervised manner can be acceptably low.