The combined effects of salivas and occlusal indicators on occlusal contact forces.

BACKGROUND: Some occlusal detection products are designed for use on dry teeth, but this is not always achieved. Others are suited for dry and wet applications. OBJECTIVE: The objective of this study is to assess the combined effects, on occlusal contact forces, of two previously studied affecting variables-occlusal detection products and saliva. METHODS: We used a full-arch dentiform with three occlusal detection products (an articulating film, an articulation paper and T-Scan) in combination with human (HS) and an artificial saliva. The maxillary arch assembly, weighing ~54 N (the maximum bite force), was lowered onto (occlusion) and lifted off (disclusion) of the mandibular arch through 10 cycles by a mechanical testing machine. The forces and moments acting on the mandibular arch were continuously recorded by a load cell that supported it. RESULTS: The maximum values of Flateral (the in-occlusal plane component of the occlusal contact force) were analysed by occlusion/disclusion separately using one-way ANOVA, with factor for group type to identify the significant effect of salivas on products, effect of products, effect of salivas with products, effect of human saliva. A difference in occlusion and/or in disclusion was considered different. Statistical differences (P < 0.0001) in Flateral were found in: dry product vs product + HS, dry product vs product + artificial saliva (with articulating film and T-Scan) and HS vs product + HS (with articulation paper and T-Scan). CONCLUSION: All products were affected by the salivas, except articulation paper by artificial saliva.

Thermal effects on pulp due to laser and handpiece usage.

OBJECTIVE: The study was designed to compare changes in pulpal temperature during ablation of dental hard tissue while using two established erbium dental laser systems, a new CO2 laser system, and a conventional high-speed handpiece. METHODS: Eighty non-carious human extracted molars were separated into four sample groups of 20 teeth each. Three laser systems were used, respectively, to ablate the occlusal surface of the teeth in three of the groups for 60 seconds each. The high-speed handpiece was used to drill the occlusal surface of the fourth group for 60 seconds. Pulpal temperatures were measured using thermocouples inserted into each tooth's pulpal chamber prior to ablation. RESULTS: None of the average temperature increases approached the threshold of 5.5°C at which pulpal damage begins. On average, the pulpal temperature of teeth ablated with the Waterlase MD system increased the most (3.56°C). The traditional handpiece caused the lowest average temperature increase (1.57°C), followed by the LightWalker DT system (3.20°C) and the Solea CO2 system (3.30°C).