Evaluation of Bite Force in Teeth Restored with Zirconia and Porcelain-Fused-to-Metal Crowns

Abstract

Background: Mastication is a biomechanical process that involves the jaws and teeth working together to effectively break down food through the contraction of masticatory muscles. The efÏciency of this process is influenced by factors such as bite force, the integrity of the dental arch, and individual characteristics, including age, gender, and body weight. Previous research has investigated the bite force of natural teeth, comparing the differences between removable and fixed denture teeth. For instance, Gibbs et al. estimated the bite force of Eskimo individuals to be 348 lbs (138 kg), while Al-Zarea et al. reported a bite force of 580.9 N for fixed partial dentures. Additionally, J. Urangua estimated the bite force of first permanent molars to be 472 N. Although studies have explored the bite force of Mongolian individuals with removable dentures, there has been no investigation into the bite force of fixed partial dentures, highlighting a significant gap in the literature that the current study aims to address. Aim: This study aims to assess the bite force following the restoration of teeth with Zirconia and Porcelain-Fused-to-Metal crowns. Material and Methods: The study involved 20 individuals aged 18 to 34 years, each of whom had their mandibular molars restored with Zirconia and Porcelain-Fused-to-Metal (PFM) crowns on one side, while the other side retained their natural teeth, which had not undergone root canal treatment and exhibited no significant alveolar bone loss. A single-instance design was employed to measure occlusal force using the Occlusal Force Meter GM10. Statistical analysis was conducted using SPSS 26.0 software, with results considered statistically significant at a probability level of p < 0.05. Results: The cohort comprised 20 subjects aged 18 to 34 years, with 65% (13) male and 35% (7) female, yielding a mean age of 28.2 ± 3.5 years. The mean bite force for teeth covered with crowns was (393.2±0.3 N), compared to (445.5±70 N) for natural teeth. Notably, the bite force of the Zirconia crown (407.0±0.7 N) was higher than that of the Porcelain-Fused-to-Metal (PFM) crown 367.7±0.9N. When analyzed by gender, the bite force of natural teeth in men averaged 484.1±46.2N, while that of crowns was 445.3±43.7N. In women, the bite force of natural teeth averaged 373.7±15.4N, compared to 296.4±19.6 N for crowns. Conclusions: 1. The bite force of zirconia porcelain crowns was 407.0±76N, while the bite force of metal porcelain crowns was 367.7±97N. 2. When determining the bite force of crowns and natural teeth, the bite force of crowns and natural teeth was 296.4±19.6N, and the bite force of uncoated teeth was 445.5±70N, respectively. 3. When compared by gender, the bite force of uncoated teeth in men was 484.1±46.2N, the bite force of coated teeth was 445.3±43.7N, and the bite force of uncoated teeth in women was 373.7±15.4N, and the bite force of coated teeth was 296.4±19.6N, and the bite force was significantly related to gender (p<0.0001).