Zirconia single crowns and multiple-unit FDPs—An up to 8 -year retrospective clinical study

Abstract

The aim of this retrospective clinical study was to evaluate the survival and the occurrence of technical and biological complications of zirconia crowns and fixed dental prostheses made in the student clinic of Turku University, Finland, between April 2009 and September 2017. Materials and methods: Twenty-seven patients (19 female, 8 male), with zirconia crowns or FDPs, participated in the follow-up investigation. The mean age of patients was 64.6 years. Of the 40 restorations, 17 were single crowns and 23 FDPs. Twenty-seven restorations were anterior and 13 posterior. Restorations were investigated according to modified USPHS criteria. Results: The survival rate of zirconia restorations after 2-8 years (average 5.7 years) of clinical use was 95%. Survival rate of single crowns was 94.2% and of FDPs 95.7%, respectively. The overall complication rate was 26% for FDPs and 5.8% for crowns. One posterior crown was lost due to a vertical root fracture and one FDP showed a framework fracture. Veneering ceramic fractures were detected in 12% of all cases (0% for crowns and 22% for FDPs). Bleeding on probing was present in 38.1% of restored teeth and 13.9% of control teeth. Embrasure space was insufficient in 52% of zirconia FDPs and 81% of these restorations showed elevated BOP values. Conclusions: Zirconia crowns and FDPs survived well in this retrospective follow-up study. Chipping of veneering ceramic and bleeding on probing were the most common complications. Thick connector areas made according to material demands resulted in insufficient embrasure spaces and inflammation of marginal gingiva.

Periodontal Behavior Around Teeth Prepared with Finishing Line for Restoration with Fixed Prostheses. A Systematic Review and Meta-Analysis

“…Most research and meta-analyses of published literature have focused on the prostheses' mechanical complications, for example chipping, and have placed periodontal complications in the background. [10][11][12][17][18][19][20][21][22][23][24][25][26][27]. Only a few works have investigated gingival and periodontal health around crowns and FDPs exclusively [2,5,7,8,20,22].…”

“…As for periodontal probing depth, several articles reported significantly greater depth observed around restored teeth than untreated control teeth [18][19][20]. Suárez and Sax found greater insertion loss in teeth prepared with horizontal finishing line than untreated teeth [12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27]. Lastly, the parameter that most clearly pointed to periodontal disorders was gingival margin migration as reported in studies such as those by Peláez or Valderhaug [2,5,11].…”

“…Gingival migration is due partly to individual patient factors such as oral hygiene or periodontal treatment carried out prior to treatment [2,5,8,11,12,20]. According to various authors, the main reason for increased gingival bleeding and periodontal inflammation is poor marginal adaptation between the restoration and the prepared tooth [8,11,12,20,24]. In this context, the position of the margin is important, as subgingival dental preparation has been seen to affect periodontal health negatively [2,5,7,8,11,21,24].…”

“…At the same time, the plaque index was lower around teeth restored with complete coverage crowns, as ceramic materials have been shown to retain less plaque than natural teeth [8,24,25]. In articles that evaluated periodontal parameters in relation to the restoration material used, different levels of gingival bleeding were observed, which were sometimes contradictory.…”

“…According to Tanner and Sailer, this is due to the difficulty of hygiene maintenance around FDPs derived from the presence of connectors of large dimensions that may compromise interproximal spaces [9,10,24]. In the study by Peláez, who compared gingival margin migration, 77.7% of zirconia crowns were affected compared with 16.6% of metal-ceramic crowns, although no conclusion was drawn as to the cause of this difference [11].…”