Vinkenborg, C. (Carolien) (2015) De ‘survivalrate’ van indirecte lithium disilicaat restauraties na 5, 10 en 17 jaar. thesis, Dentistry.
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Abstract
Introduction Nowadays, the demands for dental materials are increasing regarding esthetics, strength, bio compatibility and durability. Because of better strength, hardness and durability complete ceramic restorations have become a good alternative for the conventional metal-porcelain crown. E.Max Press and IPS Empress2 (Ivoclar Vivadent) are monolithic glass-ceramics made of lithium disilicate (LDS). Short term research shows good results for LDS as restorative material with survivalrates >94% after 5 to 8 years of function. Long term results are wanted because survival of 15 years is regarded an important standard. Materials and Method In this clinical research 55 indirect LDS restorations (e.max Press of Empress2) that were placed in the period 1997-2008 by 9 patiënts, have been evaluated. It concerned 47 conventional LDS restorations and 8 ‘endocrowns’ for the endodontically treated teeth. The patients were asked to participate in the clinical research which consisted of the making of bitewings and intra-oral photographs. Also intra-oral inspection of the LDS restorations was carried out by using a list of criteria provided by Hickel, which had been transformed to a Dutch format. Each criterium could be given a score 1-5. Scores 1-4 were classified as ‘good’ or ‘repairable’. Score 5 was classified as failure. A second assessor also evaluated each patient. A Kaplan-Meier survival analysis was carried out to determine the cumulative survivalrate of the LDS restorations. The interreliability score was calculated by using a Spearman’s Rho coefficient. Results After 7.9 years the cumulative survival proportion was 98% (Kaplan-Meier). The survivalrate was 93% after 8.9 and 78% after 17.3 years. The percentage of survival after 17 years was 90.9%. The mean time that a restoration was regarded as survival was 16.7 years. 5 out of 55 LDS restorations were classified as failure. For 4 restorations, the cause of failure was secondary cariës. In 1 case the crown had debonded. None of the failures were ‘endocrowns’. A high interreliability score was found for the following criteria: surface lustre, fracture/retention, radiographic examination and patient’s view. The lowest scores were found for anatomical form, sensitivity/vitality, cariës/erosion/abfraction and periodontal response. Conclusion LDS can be regarded as a strong and fracture-load resistant material. Secondary cariës was in this clinical research the main reason for failure of LDS restorations. Low sugar intake and good oral hygiene are beneficial for the longevity of restorations. ‘Endocrowns’ are a good restorative option for molars and possibly premolars. Regarding the assessment of restorations, a high level of subjectivity exists despite the use of a format.
| Item Type: | Thesis (Thesis) |
|---|---|
| Supervisor name: | Pelt, Dr. A.W.J. van |
| Faculty: | Medical Sciences |
| Date Deposited: | 25 Jun 2020 10:47 |
| Last Modified: | 25 Jun 2020 10:47 |
| URI: | https://umcg.studenttheses.ub.rug.nl/id/eprint/857 |
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